NOTICES OF MINING MACHINER~ AND VARIOUS MECHANICAL APPLIANCES IN USE CHIEFLY IN TIlE PACIFIC STATES AND TERRITORIES FOiR MINING, RAISING AND WORKING ORES WITH COMPARATIVE NOTICES OF FOREIGN APPARATUS FOR SIMILAR PURPOSES. BY WILLIAM P. BLAKE. NEW HAVEN, CONN. CHRALES C. CHATFIELD & Co 1871. PRE FACE. The letter of instructions from the Secretary of the Treasury, in 1868, to the Commissioner of Miling Statistics, indicated as one of the most important subjects for inquiry,' the relative merits of the various inventions, machines, and mechanical contrivances in use or projected for the reduction of the precious metals, and for all other purposes connected with the business of mining and metallurgy." At the request of Commissioner Raymond, the writer undertook the preparation of a report upon the subject, and notices of the principal mechanical appliances in use were submitted, and printed as Part IV of the Commissioner's report to Congress for the year 1870. The present volume is a reprint of that part, with some modifications. Under the circumstances, it was not possible to prepare a systematic and comprehensive treatise upon the machines used in mining, and this was not attempted. The time and means were limited, and only the intervals between other daily duties could be devoted to the work. The notices were written in the winter of 1869-770, and since the delivery of the manuscript there have been notable advances in the construction and use of mining machinery. The activity and enterprise of the miners of the Pacific slope is shown in the rapid succession of improvemnents. It is not possible in the ordinary course of publication of reports of this kind to keep pace with the march of improvement and discovery. However fresh and recent a description nmay be, before it can be published some new advance needs to be chronicled. For ex-:ample, the diamond drill, described and commended to the attention of miners in these pages, las since been put into successfuld operation by prospecting in advance some of the. gold mines of California. There has also been a fine example of subaqueous mining and blasting in the removal of Blossom Rock, one of the obstructions to the navigation of the harbor of San Francisco. Other blasting operations upon a large scale have been carried on at the Blue Point Tunnel, at Smartsville, California. Hydraulic nozzles, so constructed as to be readily adjustible to any angle, alid under easv control, have been introduced. The new Stephens and iRawlings budldle is reported as being used with great success in concentrating the battery sands at Grass Valley. A 60-stamp mill, remalrkable for its completeness and admirable arrangement, has recently been built by the UTnion Iron Works, of San Francisco, for the Eberhardt and Aurora Mining Company, at White Pine. The sixty stamps are grouped in six double batteries. There are twenty-two grinding and amalgamating pans, eleven settlers, and three agitators. IV PREFACE. It is built upon a hill-side, so that the ore descends by its gravity from one machine to another, and is not handled at any stage of the treatIent. The stamps are fed automatically, and even the quicksilver, strained from the amalgam, is returned by m echanism to its reservoir above the amalgamators. Automatic operation of machines is of great importance where labor is so scarce and high. Increased attention has of late been given to improvements in this respect. WILLIAM P. BLAKE. NEW HAVEN, CONN., Noveqmlber, 1870. CONTENTS. INTRODUCTORY. Page. THE MiANUFACTURE OF MINING MACHINERY IN CALIFORNIA... 1 SECTION I. B1REAKING DOWN ROCKS AND ORES. CHAPTERP I.- W-ATER -HYDPRAULIC MINING5.. —--—. ——...... 5 1I. -HAND TOOLS............. 10 HII. -EXPLOSIVES ---------—. —---------------------- 15 SECTI 0 ON I I. BORING AND EXCA VATING BY M1$ACHINERY. CHAPTER IT-..TACHINES FOR DRILLING ROCKS............... 34 V.-BORING DEEP AVELLS FOR WVATER OR OIL...... 57 VL. —BORING LARGE MINING SIAFTS................. 68 VII. — IACHIINES FOR CUTTING OUT COAL. —. ——.-. 76 SECTION II1. TRAN SPORTATION, VENTTILATIOXN, ETC. CHAPTER VIiI. -TRAMWTAYS AND WAGONS-. —..- ---—.. 87 IX*. —HOISTING 3ikACHINERY AND AND APPARATUS.- - - - - 99 X.-SABETY CATCHIES OiR PARACHUTES ---------- 121 X AI.-RAIxSING WATER... —------—. o —------- 130 XII. —RAISING AND LOWVERING 31INTERS ---- --—. —-- 143 XIII.-V ENTILATION ----—. —.. —-.-.-....1.. ------- i53 XIV.-SAFETY LAMPS AND FIRES IN M{INES -. —-o-.- 162 SECTION IV. BREAKING, CR USHING A ND GRITNDING ORES. CHAPTERI XV. -BREAKIING AND CRUSHING....-................- 177 XVI.- STAMPS AND STAMP MILLS...-.............. 187 XVII.-PANS FOR GRINDING AND AbMALGAMATING-.... 213 SECTION V. SElPARATION AzND CONCENTRATIOgN. CHAPTER XVIII.-THE CONCENTRATION OF GOLDEN ALLUVIA.. 223 XIX.- THE CONCENTRATION OF VEIN STUFF........ 224 INTRODUCTORY. THE MANUFACTURE OF MINING MACHINERY IN CALIFORNIA. The great demland for mining' implelments of all kinds which attendued the suddeu developmlent of gold mining in California was at first supplied fromr the Atlantic States and fromn Europe. Some of the first quartz mills erected in the State were imported fromn England. Relics of them mlay still be found in Grass Valley and on the Malriposa Estate. But this dependence upon eastern and foreign workshops did not long continue; founderies and machine-shops were started in San Francisco, ancd their extent and number has been increased to keep pace with the rapid enlargement of the mining field oC the Pacific slope. Wivith the constantly increasing discoveries of new districts, and the opening of new sources of gold, silver, and copper, the clemand for malchinery has been enormous and peremptory. But it has been most succesifully met by the mechanical engineers of the Pacific slope. Their work is characterized by great boldness, independence of precedent, ingenuity and originality; and they to-day furnish some of the best machlinery in the world for certain departments of the art of mining. The directions in which the greatest adlvanc: has been made are: 1. The improvements in breakers, staimp-batteries, &ce., ali-nd the substitution of iron for wood in stamps and ore-dressing and concentratioing machines. 2. The malnufiacture of ptans for grinding land algllamlaating. 3. The introduction of silvered and anaalgamated copper-plates for saving gold and quicksilver. 4. The art of placer mining' has been revollutionized; cunbrous andl slow w orking hand machines lhave given way to gigantic operations which in their extent and effect approachl those of iNatnre. The under current sluice is but one of the imlprovemlents to which the development of this art has led. The effects of the discoveries, and of the ilmprovenments following tllhemll have been wide-spread. In)ventiolL and pro(luction hlave everywhere been stimulated. Attention has been steadily directed to the invention of machines to be substituted for hand labor, especially in rock-drlilling', and to the improvemelnt of explosives, all tenlling to diminish the cost of moving rocl and extracting the precious ore. tock-drllilling mnachilles have passed through a great variety of modifications in the United States, and the Lesehot diamond drill, which originated in Fraanee, here finds its greatest development and its imost general and successful practical a.pplication. The iron founderies and machine-shop)s of Sani Francisco have been sustained chiefly by the demanud for mining macllinlery, and were most nuimerous and successful in 1865 and 1866S during thle leriod l of greatest expan siom in prospecting and miino':, and thle formation of companies to develol claims and mining groundl in (all directions. Th'e value of tlle castings produced at these founderies iii the year 1866 is estimated at little less than two millions of dollars, the greater portion beilong for 2 MECHANICAL APPLIANCES OF MINING. quartz mills ancld maining machinery. There were then thirteen establishmenrts in full operation, emlploying about 13000 men. The number of large esta'blishlents now in operation is somnewhat less. In aCddition to the works in San Francisco, there are founderies in the othter large cities, as Sacramento, Stockton and Marysville, Nevada City, and -at nearly all the chief mining centers, where mills are built, shoes and dies cast, aLnd repairs made. The principal establishments in San Francisco at which mi-ning Imachinery is manufacturcd are ie i Union Iron Works, the Pacific Ironi Works, the Vulcan Iron WVorks, the ~iliners' Foundery, and the Golden S't-ate Iron Works. The first unamed is the pioneer establishment,i having been founded in the ycear 1849, by the Meessrs. Donahuhe Brothers, upon a very limited scale, from Awhich it has grown to be the largest a1nd best appointed oin the coast. At the, commencen-leent, the blast for melting was produced by a blacksmith's belowIs, 7and the tools allnd materials were few and implerfect. At present, there are in the machixe-shop twenty-five lathes, eight planers, and much powerful drilling, cutting, gearing, and shapling maclhinery. One of the planers is the lalargest in the State. The smnithery. is provided with a fifteen-ton steam hamnller for forginlg large wAork, and the boiler department has automatic punchiIng a nd rivetillg machines. The mainl buil(lin-g is of brick, three stories high, with a frontage of 1871S feet, allnd at depth of 120 feet. Abont 300 men are employed. Thlle Pacific W~orks were started in 1850. In 1867 they worked up 700 tons of pig iron, 350 tons of bar and plate iron., with 700 tons of coal; and the value of the product wais $3000,00. The Vulcan, in 1867, worked up 1,200 tons of pig iron and 200 tons of bar and round iron. This brief mlzention of some of the more important of the mlachine making establishments will serve to gi-ve a genieral idea of the oap)acity of the coast fior the production of mining nlaclhinery. California not only manufactures mills aild nmachinery for the Pacific slope, for Nevada, Idalho, Oregon, Washinlgton and Arizona, but exlports to British Columbia, Mexico, Clentral America, South America, Colortido, North Carolinla, and, to solne extent, to Australia. Its stamnp-mills for gold quartz crushing are superior to aniy other, and are regarded as models to be followed. There is no country where so much monoey and efifort has been expended in so short a time in experimenting with, and perfecting: thle various machines nsed in mining; a]nd aRtlthough1 it may be said that there has been a great waste of material and money in the headlong, blunllering wa y in wllich the progress has been imade, it muIst be cltadmlitted t-hat thlle resulnt enl the whole is more satisfactory, than it would probably hlave been by tlhis time, if every problem had been the subject of slow and careful deliberation. The great value of time and labor in these inew and rapidly expandilng muetalliferous regions is to be consideredl and likewise thle enormous rates of interest, ranging from twelve to thirty-six per cent. per annum; the great cost of transportation, rangingo~ fioIm five to tA7ellty-fi-e 0celts per pound; and other conditions very different firom those in older mining regions, so thLat it is not possib)le to nallae any just comlalriso(m between the one and the other without giving a thir considerationl to thlese peculiar and difficult circunlstaiices under which the developmllent has been made. Ini the followingi notices o-f the mechanical appliances of mining the attempt has not been made to give a, complete description of thllemt all. ~Neither time inor the space allowed permitted this; but it has been the endeavor as far as possible to describe the matchinery and apparatus of MINING MACHINERY IN CALIFORNIA. 3 mininig now in use on the Pacific slope, and to add such notices of machines used abroad for similar purposes, and to make such comparisons as would be likely to interest and instruct those engaged in minillllg and to furnish the data fior a general reply to the natural inquiry, what is the position of the JUnited States in this respect, compared with that of European countries. The writer desires to make special acknowledgment to the t Union Iron Works of San Francisco for drawinlgs of stamp-mills, hoisting works. and other machinery, fromn which many of the illustrationls have been reducled for these pages. IHe is also indebted, for -valuable information, to Mr. Irving M. Scott, to AMr. Moore, of the Vulcan Foundery, and A. S. Hallidie, esq., president of the 3Mechanics' Institute. For informall tion concerning the machinery lnow in use abroad, he has consulted his own notes upon the machinery at the Pari~sExposition, and elsewhere, and the works of Burat upon the machinery of the Belgian and French collieries. Having recently, in part, rewrittenl the report upon mnining~ in the series of reports upon the Paris Exposition, lie has felt at liberty to make free use of those pages and of imany of the illustrations, electrotyped copies of Awhich had been secured for the purpose.'* Report, on mininlg alnd the mechanical preparation of ores, by HI-ellry F. Q. D'Aligny. and Alfi:ed Huet, F. Geyler, and C. Lepainteur. Washington: Government Printing Office. 1870. SECTION I.-AGENCIES AND INSTRUMENTS OF BREAKING DOWN ROCKS AND ORES. CHAPTEIR I. WAATE R-HYDRAULI C MINING. The placer miner avails himself of the results of forces which have been acting for unnumbered ages. Frost, ice, and mountain torrents, aided by the decay of rocks, have broken dow n the veins and liberated the gold, leaving it distributed under the gravel and sand in the beds of ancient andl existing streams. The force required for breaking up the rocks and veils has been expended and the work of the placer miner is rather to clean up, or harvest, what nature has already mined for him. But the operations of nature have been so vast, and so gigantic have been the deposits made by rivers and floods, that the pick, shovel, and pan are inadequate for the profitable collection of the gold, and other mechanical appliances are brought to bear. Powder and nitro-glycerine are used to blow up and disintegrate the deep and consolidated deposits; water under pressure is tade to undermine and w ash away igh y hih anks of gravel; powerful cranes and hoisting appara. tus, and for some of the harder cemented gravels -massive stamp-lmills, are required. As water was Nature's principal instrumnent in preparing these earth deposits, so, also, is water the surface miner's grea't agent for breaking down and reassorting them. It is broughlt to bear directly upon the materials, either with the momentuml it acquires in falling from a considerable elevation, or with the gentler force of a shorter fall as it runis down a sloping channel. The first is the hydIra'flic pSrocess, and the second is s8licing. The operation of the first is to break and disintegrate, and of the second to separate, assort, and concentrate. In hydraulic milninlg, the two are necessarily eonnected and form one continuous operation. Water falling through pipes fronm a height of from 100 to 200 feet is (lelivered through nozzles in continionus streams against the base of a bank of earth. It undermines the bank; the overhanging masses ftll to the base and are broken apart and loosened; the water penetrates every crack and pore; large boulders are thrown aside like pebbles; the whole mass is stirred lmnd mingled, while the accumulated waters flow away dclown the slope thick with salnd and earth, leaving the larger boulders and the gold restin, eleanl-washed upon the surface of the bed-rock. This process is applicable wherever deposits have accumulated to such a deptl- upon the lower stratlum holding the gold that they cannot be economically removed by digging. 7For its successful operation there are two essential conditions: first, sufficient hLead or height and quantity of water; second, a rapid fall or slope from t-he base of the bank, so that the water will flow sw-iftly away and carry the loosened gravel, sand, and earth with it. In Ca-lifornia there is comparatively little difficulty in attaining these conditions by an adequate expenditure of money. The high mountains give numerous streaIms flowing toward and across the gold region, and the deep valleys and ravines permit of alple fall and 6 MMECHANICAL APPLIANCES OF MINING. drainage. But the streams have to be diverted from their courses andc carried in ditches and fillumes for many miles along the hillsides, while in most, cases the best gold deposits are in troughl-like or basin-sha-ped depressions, hemmed in by rocky walls, through which artificial outlets mlust be cut, so as to give the requisite drainage. Thus, when the positionl, depth, and riclhness of a deposit are ascertained, and it is decided to work it by the hydraulic methodl the first operation is to provide an outlet for the water. This is done by cuttiilg a tunnel through the rinl-rock from an adcjoining raville or valley, so as to tap the lowest part of the basin, and, if )possible, to secure a vertical fall of fifty to one hundred feet front the base of the delposit. Suchi tunnels are usually costly and-laborious undertakings; they require great, engineering skill for their proper projection, and oftein manSy 5 ears of time. In driving some of the longer tunnels, friom five to seven years have been consumed and an expenlditure of fiom'10 to 860 1per lilneamri foot incurred. They vary in length from a few lulldred feet to a inile, and are usually fronm six to eight feet in width by seven in height. MIINING DITCHES IN CALIFORNIA. In the year 1867 there were 5,328 miles of artificial water-courses for mn-ing purposes in the State of California, besides the subsidiaIry branches, estimated at over 800 miles imtore. These water-courses are ditches cut, wherever possible, into the earth of the hillsides, alnd crossing rocky points and d(eep valleys by means of flumes, or, better, in iron pipes. The ditches are usually about eight feet witde at the top, six at the bottom, and three feet deep. The grade varies from twelve to eighteen feet to the mile. Forinerly flumes were conlstructedl on a large scale and at great cost; but now large sheet-iron pipes are substituted with great advantage ill durability and economy. Sone of the flumles were of great length and height; onle lnear Big -o0k Flat, in Tuolunllle County, being 1,300 feet long and a part of it 2586 feet above thle sutlrfalce adlc supported upon wooden towers. Upon the Truckee ditch there were, at one time, 13 miles of finie, eight feet eet ide and four feet deep, hung upon the side of a deep) cation. Upon the Pilot Creek ditch there was onle piece of flume 300 feet long and 9,5 feet highll, The boar'ds used for makingflumes are usually friom one and a quarter to one andc a half inch thick. rThey are laid down rough and thenl battened. Sills are placed at intervals of two and a half feet, with posts aindl a cap for the su)pport of the flume-box. The sills are four inlches squ:are, the posts three by four, and the caps one and a half by four inches. In addition to the first cost of a flume, it is expensive to keep in repair, and is liable to a great many accidents. It may be burned or blowni down, and if it is left dry for several months, all the boards curl up and split so that they cannuot be used again. It is said that the repairs of a flume cost 90 per cent. more tha1n those of a ditchll. For all these reasons, flumtnes are not now constructed -where they can possibly be avoided and ironl pipes are substituted. These pipes are made of stout sheet-iron or boiler-iron, and va!ry in size from 10 to 40 inches ini diameter, according to the quantity of water to be carried. From 7 to 11 inches is a coimitmo1n diameter for the smaller pipes, aind these are made of No. 20 ironm. A sheet two feet wide and six feet long will make two joints of 11-inchl pipe. These joints are put together to form. sections 20 feet long, and these sectionls are unitedcl upon the ground and secured by n:eans of strong wire wound around two projecting ears or hooks of iron, one upon each section. The whole pipe is also firmily fastened to the surface HYDRAULIC MINING. 7 by posts securely set in the ground, to prevent its AwTeight from carrying it down the steep slopes. The examples of the successful use of pipes for carrying water across depressions a1nd ravines are numlelerous. TUpon the South Fork Canal, in Eldorado County, a, pipe is used to carlry 5_0 inches of water across a valley 1,600 feet wide and.190 feet deep. Th:lis pipe is 10 inches in diameter? the iron about one-sixteenth of an inch thlick, and the supply end is ninety feet higher than the delivery. On the Excelsior Company's ditch, near Smartsville, there are five miles of low flume, 6,000 feet of 40-inch pitpe, 3,000 feet of 20-inclh pipe, alnd half a mile of 38-inch pipe. The 40-inch pipe crosses a depressionl 150 feet deep, and with a head of thirty-two feet carries 2,500 inches of water. Upon the Dutch Flat ditch there are 3,500 feet of 3-incll iron pipe and 837 feet of 32-inclh pipe. The aggregalte cost of the ditches in California for the supply of water is reported as $15,57 5,400.* They are generally built by complanies alnd owned distinct fromn the mining companies; and the water is sold to the miners at so much per inch per day of ten hours. THE MIINER'S INCH OF WATER. The miiner's inch of water is not a very definite and fixed quantity, for the methods of delivering it diffelr in different places. It varies according to the pressure or head and the leight of the aperture. Usually the pressure is six inches, and the aperture is a. horizontal slit one inlch high and about twenty-four inchles long, which can be closed to any desired degree so as to leave anI opening one inch long, giving; one inch of water, or ten or twelve incelhes long, giving correslpondling numbIlaers of inchles of water. It is thus usual to consider the niillners inc h as that quantity which Awill pass throug'h an opening of one square iuch area -under a tlean pressure or hlead of six incltes. The quantity dise:ha rged friom such an opening (one mLiner's inch) in twevity-four hours is equclal to 2,274 cubic feet. A cubic foot is equall to 7.49 United States gallos,01: or thirty-eight Iminer's inches. The Eureka Lake and Canal Company deliver water through an aperture two inches high and under a pressure of six inclles. The zamountm delivered by them through anl aperture twenty inches long and two inclles high is conlsidlered to be forty inches. Upon the Excelsior ditch, a;nd also upon the Sear's ditch, water is delivered ulnder a pressure of ten inch.es, measured from the center of the orifice. Upon the il okelulmne Hill and Campo Seco ditch, water is delivered under a pressure of four inches. The Plucenix ditch Compalny deliver it tlhrough an orifice three inches high and under a pressure of four inches over thle orifice. Upon the Gold Hill dlitch, E1 Dorado County, a miner's inch has been measulred out through an orifice two inches high and an inch wide under a four-inch pressure. Another ditch in E1 )orado County has sold for an1 inch of watter the amount that escapes through ani orifice three inches high and an inch. wide without pressure. At Smartsville water is sold with a head of' ine inches with a fourinch opening 125 inches long, giving 11.8 per cent. for an " inch"1 more than is Lsually given. Thle qualntlity (lischlarged thlrough an opeing bur inches deep, with a nine-inch hleald over the middle of the openlig with the coefficient of dlischarge:.0615 is 10)6.6 cubic feet per hour, or 1.7767 cubic feet per minute. A " head of water" is 500 inches daily for ten hours, aild is the qtuantity required for a first-class hydraulic operation. *Langley's Directory, 1867. 8 MECHANICAL APPLIANCES OF MINING. The distribution of the water to the hose-pipes-is generally by a side iron pipe leading froimn the main pipe or reservoir, and connecting at the bottom with a strong cast-ironl box. This box is provided with openings in different directions, to which the smaller pipes are fitted; and these again connect -with flexible canvas hose strongly made aindr covered with netting and bound at intervals with iron. They terminate in brass nozzles with orifices from two to three inches in diameter. ECONOM3Y OF THE HYDRAULIC PROCESS. It is not easy to estimiate the average cost of washing by the hydranlic process. It requires not only -very careful measuremlents of the bulk of the materials removed, and of the amount and pressure of the water used, but the nature of the material must be taken into the accou1nt, whethller hard or soft, cemented or loose gravel, sand or stiff clay; for the rate of progress will vary greatly according to the resistance of the materials to the disintegrating or imoving action of -the water. The following, from a report made by the writer in 1859, mlay here be cited as showing the estimlsate at that time of the value of the hydraulic method compared with hand labor: As a labor-saving process the results of this metllhod compare favorably with those attained by machinery in the various dcepartments of hunla industry where manual labor has been superseded. With one pipe of an inch and a half or two inches aperture 1andl a pressure or head of ninety feet, a boy ce'n excavate. anld wash as much auriferous elarth in one day as could ten or fifteen men without its aid. It is co1011on to estilmate the vwor of a pipe as equal to the labor of ten men; in some locations a pipe of the size mentioned miglit effect more than twenty mlen in the samle tiime. The Lwater is ever active and mltiring, and works as as rapidly in inaccessible places as upon an exposed l bnk. The quantity of earth lio oved -wiill, of course, vary greatly at different, places, depending clliefly upon its character; whether sandy, a mixture of clay and sand, or clay alone. The amount of gravel allnd bolders also varies greatly in all gold plcers. FIrom measurements made last yea r in lNorth 1aro'1ina, wher e pipe) of medium size head been in use at the Wilkersorl placer, I estilmated that wNrith a head of sixty feet, anld a ilpe of one and a half or two inches in dimlleter, over a thousand blushels of earth couldl be moved and v-\ashed in a day. If -this est.imate is correct, earth whicll contains only the twenty-fifth part of a glrain of gold, or about two mnills woroth in a bulshel, will pa.y about two dollars a (lay to a pipe. In washing by this process it is ezssenltial that t:he fall or descent of the bed-rock fiom the point being washed should be sufficiently rapid to inlsure a swift curreint in the waste wnater, so that it will carry the loosened sand and clay away in suspension or force it alon1g the sluice boxes.': In California, at Gold Runi, upon the railroad divide between Bear River and the North Fork of the American, the gravel is very soft and deep; there is abundance of water under great pressure, and all the conditions are extremely favorable for the hydraulic process. It is not necessary to spend timlle in blasting the hard cemented gravel, as at Smnartsville or to puddle as at La Porte or at Dutch Flat, to remove large boulders; the washing continues without interruption. Two men can do all the work in a claim that uses 300 incehes of water. It is estimated there that one pipe will break down as mnuch gravel as the water from three pipes can wash away; while at Dutch Flat three pipes are required to break down as much gravel as the water of one pipe can wash away. Estimatinlg, as is there done, an inch of water to be equivalent to a supply of 145 pounds per minute, or 8,700 pounds per hour, it iollows that 300 inches supplies 15,000 tons in a day of twelve hours. Estimating the qualltity carried a. way by this water as equal to one-tenth of its weight'(although one-fifth is generally allowed) it follows that 1,00 tons are moved, or 7530 tonis per day to each of the two Lmen. It is not, The gold placers of the vicinity of Dahllonegra, Georgia. HYDRAULIC MINING. 9 supposed that this result is uniformly attained, but that it has been attained under favorable circumstances..Mr. Laur, during his visit to California, in the service of the French government, estimated that with miners' wages at thle uniformn rate of twenty francs per day, the expense of the nmanual labor iecessary for working one cubic m11etre of gravel by the several methods usually employed was:* Francs. Centinles. By the pan (about).......- -.......-...-..-......... 75 00 By the rocker (about) --................ 20 00 By the long tom (about).................... 5 00 By the sluice (about).-.........................o 1 71 By the hydraulic washing (about).................... 28 Being twenty-eight centimes, or about six cents per cubic yard for mllining gravel by the hydraulic method. Aiind this appears to inelule the cost of the water, foir he states that during ten days 28,080 cubic metres of gravel were worked over with an'expense for:, Francs. WNater. -- 5...-................................... --- - 5 000 Manual labor...........8.......... 864 Sundries (about)....................-...... —..- --—..- 500 Total..-.........................-........ 6, 764 From examinations made by Professor Silliman of the quantity of water used and of g-ravel washed upon the Blue Gravel Company's claim near Smartsville, it appears that 17,074,758.15 cubic yards of water were used to wash 989,165 cubic yards of gravel; hence, one cubic yard required 17.2618 cubic yards of -water, equal to 3,486 gallons. t The whole amount paid out for water during' 43 months was 857,2617 at the rate of fifteen cents per miner's inch. The cost of water per cubic yard of gravel moved is five cents and seven-tenths, deduced floml tihe foregoing; and it is stated by Black that in the JMiddle Yuba district, with the cost of water twenty cents an inch, the cost of mining a cubic yard of gravel is seven and a half cents. TAIL SLUICING. As an example of tail-sluicing upon a large seale, the Teaff sluice, Dutch Flat, probably the largest in Californila, may be cited. The total length of this sluice is 5,500 feet; of this, 2,500 feet are 51} feet wide and 26 inches deep, in a tunnel; and 3,000 feet of its length is six feet'wide. It cost $55()000, and was four years building. Several companies deliver their tailings into it, with an aggregate of 15509 inches of water. The bottonm is paved with boulders, 14 inclles deep, and the grade is ten inches in twelve feet; but it is believed tlhat eight inches would have been better. The descent is broken at intervals of 12.0 feet by drops, or dumps, two aLlnd a half feet high in the tunnel and five feet outside. These serve to break up the masses of cemented pebbles, and thus liberate the gold. The force of the current in this sluice is such. that boulders of rock ten and fifteen inches, and even twenty inches in diameter, are swept along at the rate of nearly ten miles an hour. This * De la Production des M6taux Pr6cieux en Californie, &c. t Report upon the Blue Gravel Gold Mining and Water Coml-pany. Inedited. 10 MECHANICAL APPLIANCES OF MINING. constant pounding and attrition of the paved bottom of the sluice by the rolling rockls and gravel wear it rapidly away, this wear being as great as two inches of depth inr three imonthls; and half of the paving stories become broken, so as to be unfit for use. Froim fifteen to twenty pounds of quicksilver are put into the sluice daily, in the evening; but as the sluice continually catches quicksilver, swep)t from- the claims above, the owner is never obliged to buy any. He takes out more than he puts in. Rock suitable for paving is seleceted from the round boulders swepit down the sluice. They are stopped by means of a strong iron grating placed across the sluice in an inclined position. The spaces between the bars measure eight inches, so that only the larger boulders are arrested. A Chinaman, standing by the grate, examines every boulder that stops, and saves those suitable for thie pavement. Among other notable sluicing operations, the following may be, mentioned: Hoskins's tail-sluice, at Indiana I- Hill ravine, in sections, tlJe longest twenlty-four feet in lenegth, with intermediate abrupt pitches over rocks. There are fifteen boxes, six or eight feet wide andl two or two and a half fiet deep, with a grade of eight inche inches in twelve feet. M~oody's tail-sluice, in Ca11on Creek, double, two thousand feet, long, each eight feet wide and about four feet dceel. Kinder and White's tail-sluice, in the same cation, has two sluices, eight feet wide and sevenhundred feet long, grade three inches in twelve feet. CHAPTER II. HAND TOOLS. It may at first;, to many, seem trivial to devote much space to te form and peculiarities of tools used daily by miners; but this view will not be held when we reflect upon the imllportance, in the aggregate, of the proper construction of even the simplest and most comlnmon imple'ment. NWith light, strollg, and well-proportioned tools, the skillful miner can accomplish -muclh more work in the same time than lie possiblly could with clumsily and roughly made ones. The American shovel and the American axe may be taken as familiar examples. No one who has sufficient manual clexterity to use theml properly can fail to appreciate how -far superior they a.re to other formus for the same purposes. MBINING PICKS. There are three principal types of pickls in use amllong the miners of the Pacific slope, the "1 surface l)ick " or ordinary excavating pick; the d lrifting" or " quartz pick,".and the' poll pick,s" and a pick for coal-mrining. Of each of these formls there are several sizes and different weighlts, there being not less than 31 in all manufLctured by Johln Wright, of San Francisco, who has made mlany improvements in the form and quality. I have received froom him the following table showing the weight of each size from No. 1 to No. 31: HAND TOOLS —MINING PICKS. 11 Picks lclanufactured i-n California. Description. Description. S 1 Roulnd-eye surface..-...-.............. 4 17 Drifting-........... 4t.'2- do — d..o.... 4o....do_ —....-. - __.. 3 -- d. do...........19..-_ o ------------- ------- 19.-.....do.... 4.- dd.. o -. --- ---- ---------------- 5-! 20 do. - —.. —---- - - - 6 5- cldo.Poll....l.. --? — 6 2..P.o......... 4 7 -- do 7 23 do... 5'r.~~_-. -—..-.-. do. —.-.. ——.. - -—.. ——. r i.-......do - - - - - - - - - - -..51.... 8 Flat-eyAe snlrface-4 4.. - —............ 24 d...o...l...........-. l 9 -. —..do -....4'. —--—.. —--—..... 4i 25 -.-.do......-.-.-......... 6 10. —--— do -—... --.-.. —..- -. —----—....... 5..26 do.-... 611 -.-.. do. ——... ------—..........-.-..........-.. —---- —.................. 7 12......do.-............................6 28 Coal..........-..-..-..-..... 2 13 - do.-....-............ 61. 29 -. do -.- 14- d- (lo ---.-.. 7 7 30 -...do -----------.... 15 Drifting-3...do.....-.....-do......-... -....-.-.-.-...... 16..-. o.. —-..-....- -... 4....... Smtrface p ick.-Of the surface pick there are two different styles, the round eye and the flat eye. The first is tile com on round-ll eyed excavating pick, lNos. 1 to 7, weighing from 4 to 7 ponnds, each sueceedling niumber being half a pound heavier than the precediglg. The 5-pound pick, No. 3, is;about thie llediuml anld sual size, and is 27 incihes lou lo; No. 4 pick is 27- inches long; No. 5 pick is 28 illlces, and so on1. The next numibers, from No. 8 to No. 14, are made witil fith eyes, 3 inlches by 1 i nch, while the round eye a-re 2 inches by 3 inches for tlhe lleiulm size, varyiln t trifle with the size aund weirght of tle pick. The lelogthls a(reatibout the sa1ie il botll styles of eye. Tile roud-eyedl picl is gellerally used ill sulrf'lt e or pi lace r lining, goad is plo;:bably tille l0C i teo: riekt fll si rI ieaCile iCil tk fo that work. The, e~ye being large, it is easy to fit a halldle atnd it is less liable to break. Thle eye7 a(s llade by MrAr. Wrioght beino len lthened or raised upon thle handle firoll 2 to 3 inches, gives a firt bear:ing to the Ilandlle, an1l(d is a great improvenelen t upon the old style which merely has a lip on each sidle of the eye. Th'le fiat-ey-ed plicks la-e the satne advanta~ge; aicd tlhe i 0tvoid all necessity for strtlpping thle ln:tldle. This style is preferred for sluicillg, as they do lno, spaltter the w auter so muclh as those nith the round alnd thicker eye. The heavcier picks of these styles are used chiefly in g(Trading and lheavy digging in bed-rock. Surface Pick. The formI of the surface pick is indicated by the figure, giving a side view of the medium-sized pick, dtrawn to a scale of one-eightli. DrijXtimfg or qa?rtZ 2,)ic7'.- The five lulllbers, frnom No. 1o to iNo. 20, Ccolrn prise the different weights of thle " driftiiglg or 1 quartz pick' ilad8 81shn1arp at each end. The medium size (No. 17) is 24 inches lonlg Aith an eye 3 inches by 1. inch. The form is shown by the wood-cut. Drifting or Qnartz Pick. The weight of this form of pick ranges from 3,- to 6 pounds. The 12 MECHANICAL APPLIANCES OF MINING. smallest size (No. 15) is used chiefly in contracted, narrow drifts, where there is not much room to swing the tools, and also in working out the gouge or selvage from quartz veins. The sizes 16, 17, and 1S are mostly used in drifts where there is plenty of roomi and in pulling downl rock.'These picks also have the raised eye, and are a great improvement upon thie old style. The latter are raised at each side, and have a bearing of only 1- to 1- inch; while in this construction the eye is lengthened from 21 to 3 inches, and thus gives a firm support to the handle. This is very important for the drifting picks, since they are much used in prying, and in the ordinary construction the handle is apt to become loose. Tlhepoll pic7l. —The "poll pick" is a favorite form with miners, since it combines the long, sharp point for drifting and a hammer-head for striking and breaking the rock or driving gads. It is a pick and haummner combined. The form, with the raised or socket eye, as manIufactured by iMr. WVriglht, is shown in the figure. Poll Pick. The medium size, (No. 23,) weighing 5 pounds, and about 16- inches long, is most ill se; but the weight varies iromi 4 to 7 pounds, some miners!)referring the largest size. It is a forin common in most quartz mines, and especially liked by Cornishmlen. Stuch picks are im-ade stout and strong. The hammer end or head in the medium size is 3~ inches long and the point about 10 inches, the eye being 3 by 1 inches. These various styles of picks are made of the best quality of ironl and steel, and for excellence and beauty of' finish are unsurpassed. Tlhe handles are made of white hickory, are usually 36 inches long for the surface picks, and 34 inches for the drifting and poll-picks. The poll-pick is evidemitly made upon the Cornish pattern. In Cornwall the head is usually about 15 inches long, and the handle from 24 to 26 inches. It varies in weight according to the ground to be worked; but 3 or 4 pounds are the Lmost comnion weights- occasionally 5 pounds. For working downwards a 10-pound head is often used. The poll-pick is the most alproved form for workinlg in vein —mines throughout Cornwall, IDerbyshire, and the north of EnIgla'nd. The double-pointed pick is more used in collieries. Those used for under-cutting coal, caled the "' holing pick,"1 have handles froml 27 to 30 inches long, and in South Wales 34 inches. Picks with handles of unusual length are used ini England at the Box Tunnel stone quarries, where the stone is soft and canl be cut like coal, and has to be cut out in great blocks. The handles are from five to six feet lmong1. WVhlen the mu1en lhave strucki tlhe blow they drop the picia anti then draw it out. In thle extreme west of Cornwall, where the lodes are very narrow, only 3 or 4 inches wide, the anllers u$se whalt is knlowrn an2ionLg thelm as a " 6packer7"o 0' Ipoker." It is nothing more than a, long werdgc, and is co1mmon at St. Ives and at St. Just, and the peninsula of La.nd7s End. For purposes of comlparison, the following table will be useful. It is compiled partly from tile measurements of mining tools exhibited in the AMluseLumu of Practical Geology, attached to the Royal School of Mines, in London, as enumerated in the descriptive catalogue of that institution: HAND TOOLS —MINING PICKS. 13 Dinmensions of minig picks of sevecral countries. 4Z seb s G Description. Inches. linches. lbs. oz. 1 26. 0 17. 7 4 8 Cornish poll-pick for hard ground: Length over eye, 2.2inches; of poll-end 3 inches; of picki-end, 12.5 inches; thickness (depthll) t poll-end, 1.2 inchi at pick-end, 1.1 inch; width over eye, 3.1 inches; at poll-end, 1.2 incli; at pick-end, 1.1 inch; poll-end 8-sided; point set at 85~ to handle. 2 26. 5 22. 6 2 10 Cornish poll-pick for soft ground: Length over eye, 2.1 inches; of poll-end, 3 inches; of pick-end, 17.5 inches; thicklness at poll-end, 0.8 inch; at pickend, 0.9 inch; width over eye, I inch; at poll-end, 0.8 inch; at pic.k-end, 0.8 inch; point set at 83~0 to hnsdle. 3 29. 0 15. 4 4 6 Derlbyshire doable pick, use d in rock or vein, with short points. 4 29. 0 15. 7 3 10 D)erlshire "slitter," doluble, one side pointed, the other horizontal edge, 0.4 inch swide. 5 28. 0 10. 7 4 6 Deri)yshirne )oll-pick, (mandrel,)short, bluff point; for hard veins and rock, whllere "slitter" is too slight. 6 25. 0 18. 9 4 6 Nortllnhul berland, double, straight-armed; arms thickellned in the middle, like two lgads. 7 29. 0 15. 2 5 2 Flintshire, single-pointed, owithl short 8-sided poll. 8 29. 0 21. 0 5 14 Flinltsllilre, (louble; one wedge-poinit arm, tile other with horizontal, chisel edge, 0.1 isnch wide. 9 19.1 17. 0 2 12 Mi111oniloutlhshire (coal) cutting niandriels; straight, taper directly fron 10 20. 4 17.0 2 14 cell-ter to points. 11 33.3 19.0 3 5 12 33. 8 19. 0 3 5 MIoniouthshire holing mandrel, stronger and bluffer. 13 33.3 18.0 3 8 14 30. 0 22. 3 6 6 Meoninoutlihshire bottom mandrel; curved, double-pointed. 15 30. 5'21.3 7 3 Alonmonthshlire bottomlll iandrel; curved, 2 chisel arnls-1 horizontal, 1 vertical. 16 30. 7 24. 0 9 5 Mionmoliothshlire rock mandrel; curved, 8-sided arslis-1 wedge-pointed, 1 chisel end. 17 27. 6 17. 2 3 10 Flilitshire (coal) mnetal-driving picdk; tapered V chleek-pieces. 18 28. 3 18. 0 2 10 Flinitshlir e (coal) holing pick; tapered V cheek-pieces; chisel-edged arms, 0.1 inchl wide, awitll strongly curvedi top surface. 19 27. 5 16. 3 3 0 Flintshire (coal) headingd pick; tapered V check-pieces; slightly curved; arnims talper reg"larly. 20 32. 0 17. 8 4 5 North of Eng land,, (cool;) lower elge hlorizontal; top, 2 inclined planies; in plan, a lozenege, diminishing filom celiter. 21 32. 0 18.0 4 5 North of Enlllandl; like the foregoing, except that the arlms are bent or anlcholred, meetingo at 155~0. 22 30. 0 19. 7 7 0 North of lEnilanld stone pick; slioitly anchorled; taipering V cheek-pieces; allrms bovetle(i to 8-sided sections, w;ith 4-sided pyramidi' at poinlts. 23 30. 0 23. 0 8 0 Ntortll of iEngland stonle pick; like the foreegoing, but strongler anld Ioroe alncllored. 24 27. 7 13. 6 5 6 Saxon pick; singlec armed; tapered octagonal sectiol; no poll; greatest thicklness, 1.5 inch; breadth over eye, 2.12 inches; head set at 85" to lhandle. 25 20. 5 15. 4 4 3 Russiasn poll-pick; slender curved arn l; lengt-lh of pick-eind, 12.8 inlches grseatest dliamleter, 0.7 inch; eye circiular. 26 20. 5 12. 5 3 6 Riussia; gravel pick; sinlgle curved arm; blade broadens to a spoonbill near the point. It is curious to notice how great are the variationls in this apparently trivial tool among dlifferent nations. Yet the proper foram of a pick is not unimportalnt. If it only affected by a sInall fraction (and it does more than that) the amount of woirk wTiilch a laborer can pertforml daily, its aggregate importance to the effective daily labor of tlle world could scarcely be estimated in mlloney. Our Am-ericaln patterns ard so excellenlt that there is little excuse for those who do not select the' tool best suited to the n-orlk. The Saxon gad reselnbles a long slender hammer. It is furnished with a nairrow rectangular eye. When inl use, it is lhel(l by a handle inserted into this eye, a:Lnd is driven by striking the poll-end. A comlon111011 size is, length of tile iron, 6.2; of the eye, 0).86; of the handle, 14.0; breadth across the eye, 0.95; greatest depth, 0.7 —all ill inches. The point is formed by a snmall bluff pyrcalnid, and the poll-end also contracts suddenly. Weight, 10 ounces. As the Saxon ininers are enabled, friom the fissured character of the rock, to make considerable use of these gads, they carry them under-groundc in sets of a dozen or fifteen, strung 14 MECHANICAL APPLIANCES OF MINING. by the eyes upon iron stays, with a joint or yoke in the middle, so that the whole imay be slung over the shoulder, the gads being equally distributed before and behind. The gad passes over, as it were, by degrees into the pick. Tihus the.itae1el is a large hammlller-like gad, weighingl with handle, 2 pounds, 8 ounces, antd havsing a head 10.2 inches and a handle:12.6 inches long. The small heavy poll-pick, weighing 7 pounds, 12 ounces, is very similar in form, but has a head 13.5 inches, and a h(andle 19 inches long. The ordinary German gads, and those of Huanga;ry, are stronger and more hatmmer-like than those of Saxonyl. The Hiung(arian steel gads weigh 13 or 14d ounces, and the common gad 2 poIunds 6 ounces. HAND -DRILLS. The hand-drills in California are made of English octagon steel, gelnerally one inch in diameter for ordinary powder; sometimes, but rarely, 1- inch; and the striking hammers weigh from 8 to 10 pounds. For the new II giant powder " a three-quarter-inch dirill is used, and the striking ham-mers weigh froml 3 to 5 pounl s. The use of proper copper-tipped tamping bars is rare, but safety-fuse is universally employed, so that the risk inr using iron bars is somlewhat dlilinished but is by no means remrovetl. The following pertinent observations upon blasting altd hand-drilling are from notes of a lecture by Mr. Wa~rrington Smyth, of the RIoyal School of lines, Englaind: The introduction of gunpowder has been aD irlmense boon to mining uudertaklinigs.. It not only eni ables the miniers torork upon reocks of great hardness at an economical rate, but it has led to the enlargement of such exc[avations as drifts and levels, and so placed the workmen in a better position as to ventilation, confort, and health. Formerly the minlers, when cuttillg the rock, were eompelled, by the lnarrowness of the levels and smallness of the wrorkinSg places, to inhiale the dust made by themnselves in piercing' the rock, andc their lives were shortenedl in a frightful degree. The mines, since the use of gunpowder, have had to be arranged with greater regarl for ventilation, and the cylindrical holes ori thei gunpowder are now often, while beiong bored, kept full of water, and the old injury to the breathiino faculties are for the most part avoided. There are, of course, occasions and places where gunpowder could not or ought not to be used. Where, for instamce, fire-damp is common, and it is inecessary to use safety-la-aps, the lightinig of a fuse w itlh ain open nlatch wvill be most dcangerous. In nmatny collierieos a certain man is employedcl to fire the shots, whose diuty is to test the places befoirehanld, and see that no g'ases are present in quantities sufficient to take fire; but, as Ae all kinow, accidents do oceur very often, and it is much to be clesired that the practice should be greatly restricted, if not done away with altogrether. Another case in whlich gunlpowder should not be used is where the seamn is much firactured alld fissured inaturally, so thalt a shot wrould result in so lare a proportionll of smlall coal as to nmake the -working unremunerative. Again, its use is inadnlissible in qularryiLg nmarble, or other stonie, where it is an object to obtain the rock in large and perfect masses. The methods of employilg gunlpowder clre, to a great extent, the salne in principle in all the minini districts of the world. At first in this country, as elsewhere, boringm the holes proved a slow and imperfect work, but, nevertheless, it soon came to be observed that )by cutting anway undcerneath, anid then blowving the rock or seamn down by gunpowder, one man'n could do as mulch as six \witll a hammer and gad alone. This, then, at starting renders it possible for a mine to be taken up and worked to profit wlhich could not formerhly hcave been done. Tihe hole is bored, the powder placed in it, either loose or in a cartricd(e, it is then filled up, or " tamped," to the surface, aud a fuse havilig been arranged, it is ired, calcd the result is thlat; a portion of the rock is blowTn down. The hole is bored with whal-lt is called in different places ~a " junmper," a'" drill," (Fr. pistolet,) or an " anger " —a piece of iron wAxith a sharp steel ending called " a bit," whliChl nay be slhsaped in various forms, ancd then struck in the hole with considerable force anmd dexterity by the workmlan, ciuntil gradlly a suffiCient depth is pounded out. In miiost cases it is struclk with a hamlireer wielded by tle borer sille-hanldedc, but sometimes one main holds the juliper, a nd turns it after every stroke, wrhile two men strike alternate blows, anlld thus r greatlxy a.cceliate the wnork. The lacroer aulgers are usually from onie anld one-half inch to tw o and one-half inlches in dianmeter, and in Germany it has been proved by experiment snialler bits are not advisable. The ulaterial of which HAND TOOLS-DRILLS. 5 these borers are made has been a question of great importance. Ab)out eighteen years ago, the blar of the auger was almnost falways ia.lde of ti e b1est fil)lols iron, the head being of steel, and the bit or edge of the best shear steel. In Derlyshlire, however they were accustomed to use ea st steel, which in the flnor-splars usual there, of very m-odcerate hardness, did ve arxy well, and lasted so lolg th bor.-t is eltcqiaIthed ithi ir augers to their sons; a very differett staite of things hfieoi that l f f other di vic::,:'.i auger often -would be eorn outt in a day. Ca st steel, oe ver 11. s tn1 si -l if i ted generally for iron; alnd th at becauset it, is not o1l mlore ecollmlica:l but the 1i,{)e,N'iv\'cn on the head of an ailoeer of cast steel is transmitted so lnmuch quicker to thie ed: (: as to give it a decided advantane over iron agiiers wxith steel bits. It hla(l lon hwell elbserved that -when the borers hadl \woriked for soinie timle iwith the ir(on1 tll!;:ello change. in the metal was produced, aintd the blow became miore efifective. tl:1- ait liist. Since 1852 steel augers hlave, however, become greneral, in spite of -lle i rcatler tlirst cost. In a case i No rth WaTiles, where very accurate accounts w \tere kept, it w(aIS f'ullid that the use of steel borers decreasesd the cost of workilli nlearlyi tenl Ire' ellt. hile forll of the cutting edge varies l good deal. W'henl the ground is l:n1od'at:cly- si;ef't -.ilc ortlinary chisel-shalped edge prevails. In the IHartz it is ofteil clrviilinelr. I ttly the borers have two edles at riu-ht anles, while i MIexico they are swallow\-tailed. In all cases, 1ho ever, the borer niust be turnled after evTely blow tlrough a small pertion of the circle, so that the edge never falls upon exactly the suale plahet. ATN lie the bottom of the hole is cloggedl -wxith the lebris proiluc l by the cutter, the hole is filled with water, whrliceh w'ashles oat a good deal, aid a scraiper talkes out whliat is left. There are ma.uy circnmstances under which it is nleceissary to put down 1 holes; of a larg'er character and then the augiers are made larg1er and longer anid the lhaminiier(s to strike it heavier. Stuageis are erected in such instanlces, so that on. eaclh stia;e severIal men nlay be placed to raise the auger, and thus a dozen 1ien iiiy am it a wordl of commnand all lift and let go together. A jumlper of this kiind nmay wei(gh from two to three hunndred-twleiglht. In cases of this kindl the sprinlg pole may be used to advantagiLi e. This brinogs us to the question xwhilether or not mIlachiinery may be emiploye(l for the p)urpose of boring, ancd whether it caInnot be dlone at a less expenliture e of human latbor, and more r1apidly. Among the mining tools that attracted some attention at the KParis Exposition, was an alpparatus for enlarging thle holes in rock lmade by an ordinary drill. the object being to secure an enlarged space or chainber at the bottom of' the hole for the reception of the powder. The apparatus is described in full detail in the Exposition Reports; but as it does not appear to be of any practical value, it is not repeated here. It is, however, well to mention that, in 1864, a milner from Humboldt County, Nevada, made a drill for the same purpose anll in a similar mllannler. It was known as Liinscott's Patenlt Chamber Drill, and was nade, and tested upon granite blocks, at San Francisco. It consisted of a bar of steel or iron, about two and a half feet long, with movable cutters, or steel blades, about two inches long, fi-tted into recesses, one on each side. These, when passed to the bottoln of the hole, would:fly out and cut upon the sides of thle hole when the drill-bar was struck nponl the top with a sledge. t11 this way, a chamber some three inches in cliameter could be ncmade at the bottom of an ordinary one or two inch hole. The various forms of apparatus for drilling -by steam-power or com-llpressed air are described in another chapter. CHAPTER III. E X PLO SI V ES. " Nothing is more surprising, considering how early g'unpowder was invented and used for the purpose of piercing and shattering the bodies of men, that so great a le.ngth of time should lave elapsed before its application to the purpose of blastig rocks in iilhing. The discovery of gunpower for warlike purposes took place in 1354, but it was not introduced into mininlg until the last century. In a curious old book. published in 1700, entitled'sFamliliar Discourse Concerning the M3ine 16 MECHANICAL APPLIANCES OF MINING. Adventure,' which, among other things, compares the use of gunpowder as a newly introduced system. of blasting with the old method of wedging down the material in mines, its Luse for mining purposes is supposed to have been first proposed at Freiberg, by Martin WXeigal, in 1613, but the idea met with little countenance, and it was not till 1631 that it began to be generally employed throughlout Saxony, the Ha.rtz, and North Germainy. The practice waTs first adopted i1 Englllund in. 16707 at tihe Ecton Mines, in North Staffordshire, but the blasting at that time was but a clumsy process, and was used to blow in pieces masses of rock which had already been freed from their beds by other agencies. We Inust nltt, however, be led astray by statements in books respecting the earlier use of gunpowder in mines, as the older references to' firillg' lbelong to the still rmore ancient practice of' fire-setting,' which dates froim a very early period, and was, no doubt, employed by the RomLlalr s."-x EvenT so late as the year 1862, gunpowder had not been introduced in mining in Japan, and it was introduced there fbr the first time by Mr.i Pumlpelly and the writer, acting in the capacity of mining enlgineers to the Japanese government. Up to that time the miners of Nipon and Yesso had cut their way through the rocks by means of the pick and gad, aided sometimes by fire, and they were very greatly astonished when they saw the hard rock at the end of a drift, abandoned by them because it was too hard to cut, thrown dcown by means of a few onunces of pow der. The colnsumnlption of powder for mining purposes upon the Pacific Coast and in our mnining Territories has always been large. A part of this is of course used in tile construction of roads and grading for railways, but of late the conlsumption for breaking up the hard cemented conglomerates of the deep placer deposits has greatly increased. For this purpose very heavy charges are employed. Tunnels are driven inwards for 40 to 70 feet froln the face of the lbanlk, and cross-tunnels run for 100 feet each way, so that the excavatioii has the formn of the letter T. A cllarge of fromn 100 to 50)0 kegs of powder is placed in the crosstunnel, anId the whole is simultaneously ignlited by electricity. The efeect is to lift the whole deposit, and to shatter and loosen it to such a degree that the rest of t-he disintegration is readily effected by vwater. Two companies, with adequate capital, are organized for the manuficture of porcwder ilnCaliforlia. The demland for powder for tllose regions which usually draw their supply fiom. California, is reported to considerably exceed 200,000 lkegs annually. The works of the California Powder Company are the only olles nlow in operation. At the millts of tlhis company, situated at Santat Cruz, there w-,ere mlanufactured as stated in the following table: Polwder matfalfchted ill Califo)iCa. BlSporting, canllnon,all Yeanr.' m 1u1t lblnsket powder; Total. s. equivalent to kegs. 1867-....... 150, 454 7,269- 157, 7231 1868......63,033 6, 871 69, 904: — 1869-.........-.... 130, 151 2, 439 132, 590 343,638 16,580 360,218 Pr From notes of a lecture by Mr. Warrington Smytll, at thle Royal School of Mines, London Mining Journal, January, 1870. POWDER, NITRO-GLYCERINE, ETC. 17 Besides the above there has been some powder made at the Marin Mills, probably not exceeding 30,000 kegs of blasting powder, in the years 1867 and:1868. With the facilities now possessed by the California Company, they can turn out 640 kegs of powder daily. The kegs contain 25 pounds each. The materials for making powder are abundalnt and accessible in California, with the exception of niter, which is to a great extent replaced by nitrate of soda from Peru. The peculiar dryness of the air in California for the greater part of the year permits this more deliquescent salt to be successfully used; and, with proper precautions in the manunfacture, it makes excellent powder. The capacity of the two mills is over 1,)000 kegs of powder daily. A recent modification of the manufacture promises important results. Glycerine is added to the grains in some way not yet made known, and it is said to greatly increase the strength. Works for the mnanufacture of safety-fuse have recently been erected in San Francisco, so that the miners can now obtain an article superior to that which is imported.:Notwithstanding the famililarity which all who use powder nmust gain with the many causes of accident, it is extraordinary that there should contille to be so much carelessness and recklessness in its use. One of the British mining inspectors says that in blasting an iron instead of a wooden or copper ralimmer is still too often used in getting the wadding and first part of the stelmuing fairly bedded upon the powder, and shots which have maissed fire are still drawn, although experience shows that, even with water in the hole, the drill goes in advance and fires the powder. Accidents are also frequently caused by driving the pricker down into the powder. The mineral statistics of Victoria, Australia, give exact returns of the quantities of gunpowder issued at each of the imining districts where there are magazines. In the year 1867 the quantity in stock, at the comnlecement of the year, in all the districts was 71 tons 16 hundredweigit; the quantity issued during the year, 196 tons 13 hundredweight; the quantity received during the year, 186 tons 12 hundredweight; and the quantity in stock at the end of the year, 61 tons 15 hul-ndred-weight. In many parts of the colony, however, there are no magazines, and great quantities of blasting powder are used there, of which there is no accurate return. NEW EXPLOSIVE COMPOUNDS. In introducing the subject of the new explosive compounds, which are now attracting much attention from engineers and miners, I cannot do better than to cite from the authority imentioned at the commencement of this chapter: Of all explosives used for blasting powder is the most largely usedl, and continues to be the most popular. It has been, however, proposed, and that many years ago, to mingle with it various subst.ances, and it has been tolerably well made out on the Continent that the effects of powder have not been deteriorated by a moderate proportion of sawdust being minglecl with it,. Within comparatively a very few years propositions have been made to completely change our explosive, agents-as, for instance, by guncotton, which seemed to be peculiarly adapted for blasting purposes. It is difficult to enter upon the comparative merits of different classes of explosives on account of the great jealousies which are indulged in respecting them. This is the case even with powder, every separate manufacture of which has its advocates. Gun-cotton has, however, been most successfully employed in many places, among which may be mentioned the important quarries of the Austrian government up the Danube. In England an improvement in its manufacture was made some time ago, by which it is produced in the 2 _ 18 ~ ~ I~MECHANICAL APPLIANCES OF MINING. form of a tope, anId can tthus be Cut off into convenlient lengtlhs. i By tile newer Iethod, mnanufactured on a considerable scale by Messrs. Prelntice, of Stowmarket, it is miade into a pulp, anid then compressed so as to take up less space. IBut even in its rope form gnn-cotton has an aidvwutage over gunpowder, as, takling weight -for wxeight, it wxill do five or six times thle w ork of gunpowder. Besides this, six ounces of powdere ill occupy eight inches of a bore-hole of given dianlieter, while one ollnce oi gunl-cotton, which has the same explosive poxweri, will take np onlly five and a half inches. Then, iun-cottonl makies little or no snlolke, althoulgh the small valpor it leaves is deletorions, if it may be judged by the sensation of heaidache and dimnness of eyes, xwhich it produces. Another iinportant explosive is nitro-gllycerine. year or two a(o limiht ha-ve saidm a good deal as to its cominl into play witlh t advantage, and its general adoption in this country, particularly in Northl Wailes, whereit w-as mulch used. Indeed, in somne mlines and quarries, wihen it wNas left optional with the men (who for tle imost part are a careful race, and to be trustedl in such matters) to use either gunpowrder, nitro-glycerine, or gun-cotton, a considerable proportionl preferecld itro-glycerine. They lnot only found that its explosive force was tremendously greater, but that it was more convelnient. Thus, when the bore-hole was comlpleted it had only to be filled fnll of- w-ater, and the initro-glycerine poured in. By its greater specific gravity the latter sinks to the bottom, and then the introduction of the fuise, in connection with a coopper cap at the bottom, was attended -with no difficulty or dauger, and the results of the explosions iwere tenfold. Unfortunately, the carelessness of those -who had charge of nitro-glycerine gave rise to fearful accidents la.st sunmer, and in a sudden panic, as it seems, an act of Parliament was passed, which has practically made its use penali. It is true those who want to use it are allowred to inake it on the spot, but every one kinows that that permission is of little value, since its ma'nufact, ure requires a good knowlvedge of chelllistry. Mining dgents alnd managlers, therefore, very naturally get rid of the difficulty by giving np its use, and for the present, therefore, in this country it may be said to be tabooed. If, however, the risk attendant upon its conveyance can be got over, it seems a grea+t pity to shut out from linining operations a blasting agent of such enormlous power and utility. It has, therefore, been prepared in the form of a powder, called "' dynamite," the invention of M. Nobel, of Hanmburg. Before giving a description of this new material, now largely used upon the Pacific coast, the nature and properties of nitro-glycerine will be briefly noticed. NITRlO-GLYCERINE. Nitro-glycerine was (liscovered in 1847 by AI. Sobrero in the laboratory of Professor Pelouze; but public attention was not directed to it as an explosive until the labors of 3M. Nobel, a Swedish mining engineer, were made known. This liquid is obtained by the, actionl of concentrated nitric acid, or of a mixture of nitric acid of 400 strength and sulphuric acid of 660, upon glycerine. It is formed like pyroxyline, and is, in fact, a trinitrate of glycerine; the reaction being represented by: CG HI 06 + 3 NO5 HO = 6C H5 O3 3 ~OT5 + 6 6HO. It is a yellow liquid, resembling olive oil, without odor, and possessing a sweet, slightly fragrant taste. Taken into the stomach or absorbed through the skin, as of the hands, it is poisonous, and its vapors give violent headaches. It is soluble in alcohol and ether, but not in water. It can be heated up to 2120 Fahrenheit without decomposition; but at about 360~ it detonates with extraordinary violence. It dcletonates when struck by a hammer on a hard surface or even upon wood, and the mere opening of a wooden box in whichl tinl cans of the oil were packed has been known to explode it. Pure nitro-glycerine does not appear to be liable to explode spontaneously, but if impure and acidl it changes into a mixture of oxalic acid and glycerine, and may explode. Of gunpowder, according to theory, only 50 per cent. is converted into gas, one volume giving 260 volumnes of cold gas, deduction being made for the expansioin produced by heat. Practically, however, the combustion is never so complete, and 200 volumes of the cold gas are, therefore, in all probability, above the average result. NITRO-GLYCERINE-GIANT POWDER. 19 In the combustion or eSxplosiol of nitro-glycerine seventee equivalents of oxygell out f the eighteen are absorbed by conibininig with the carbon and hydrogenl, thus leavin g one equivalent of oxygen free. Each one hundred parts of the oil when exploded produee by,weight: Wlater.-........- —................ 20.0 )arts. Carbonic( acid.... —...- -... 0 parts. Oxygenl.......-.......-.....-.........- -.- -. 3.5 parts. Nitrogenl... - - - - - - -... 18.5 parts. 1t)0.0 d1 as the specitic weight of the bitig oils 1.6 Steam-n.-.-.-.-. r__- __55___. v olumes. —-- --- j olm-neS. Carbonic acid..-.......... 469 volumes. Oxygen gas-.....-.-. —. 39 39volunes. Nitrog'en gas..................... — 236 volumes. A total of-.-....- 1, 298 volumes It is assumed that thle heat generated by the explosion of nitro-glycerine is at least twice that generated by gunpowder; consequently, if a volume - of powder gives 200 volumes of cold gas, expanded by heat four times = 800; a volume of nitro-glycerine gives 1,300 volumles of cold gas, expanded by heat eight times, producing 10,400 -volrumes; so that nitroglycerine possesses about thirteen times the powert of gunpowder when volumes are compared, and eight times its power for equal weights, the specific gravity of powder being taken at 1.0. It is claimed by the agents for the article in San FErancisco that one pound of the blasting-oil will pIroduce effects equal to ten pounds of gunpowder. The first requires but one bore hole, whereas for the powder about ten holes of the same dimensions will be required. But the sad experience with this dreadful explosive has been such as to prevent its general introdlction in mining. Californians will never forget the destructio.n of life and property which a single box of it wrought in an instant at the office of WVells, Fargo, & Company in San Francisco. This, and the destruction of a vessel at Aspinwall, and several other dreadcful accidents in various parts of the worldcl, have been a practical refitation of the theories of the comparative safety and harmlessness of the oil under ordinary circumnstances of storage and transportation. These accidents, showing the iimpossibility of controlling this agent of such wonderful power, led to the introduction of a modification of it in the mixture now known as dCynamite, or "g'iant powder.;" GIANT POWDER OR DYNAMITE. The invention of this compound dates fronm 1867, and it has been in use for nearly two years at some of the mines upon the Pacific coast. It is formed by mingling nitro-glycerinle with infusorial earth, and it resembles moist sawdust in appearance. A company has been organized for its manufacture in San Francisco, an61 the consumptioo of it is steadily increasing. The following descriptions of the powder, its properties, and the methods of using it have been supplied to me by the general agents for the Pacific coast, Messrs. Bandmann, Nielsen & Co., of San Francisco: Genelral propemrties.-It is an ungrained powder, of a grayish brown colorl with a specific gravity of about 1; insoluble in water, and not affected by tinme or exposure to air or moisture. It congeals at about forty-two degrees Fahrenheit. It sometimes 20 MECHANICAL APPLIANCES OF MINING. produces a temporary headache when taken into the mouth or stomach. The same effect also follows its continued handling. In the open air, or in ordinary packing, it burns without exploding. Its combustion produces carbonic acid, oxide of carbon, hyponitrous acid, and water. There are three, and only three, methods of exploding it: 1st. By a violent explosion either in it or into it. 2d. By confining it in a very strong and tight vessel, and setting it on fire, or heating the vessel sufficiently. 3d. By a percussive shock so intense as to produce heat and violence equivalent to an explosion. Unlike gunpowder, its explosion is instantaneous-the entire mass of powdrer explodes as if it were a single grain. This quality, il connection with its extraordinalry evolution of gases, causes its explosive effect to be especially great in solid substances, so mnlch so that, the powder cannot be used in ordnance or fire-arnis, the gunll beino blown to pieces instead of being discharged. Its explosion produces carbonic acid, nitrogen, oxygen, and water. Packing, tlransportCltio,, acd slo rale. —-The powdler may be packed, stored, and conveyed in all the ordinary ways. The fact tllat the powder is explosive, nmaturally suggests the idea that it is dangerous; but it is in reality no more so thlal corn l meal. Practically, it cannot be exploced by accident. It requires design' and careful lpreparation to explode it. The only practical caution necessary is to keelp other explosives away from it. Fire alone w ill not explode it, nor heat ill nly form —they will burn it to ashes, like saltpetre paper, without exploding it. Nor will any amount of mlere weight upon it, or simple pressure of any kind, explode it. It cannot be exploded by any of the ordinary movemlents, accidents, or incidents whllich attend its hanclling, transportation, or use. The pressino it into cartridges, or ramminin it into bore-holes with a wooden rod, however hard, throwing it about, or jostlinlg it in transportation, or even the crushinlg or violence of overturning wagolls, collisions of cars, or explosions of boilers, will never explode it. But heat and pressure combined will explode it, provided they are of the proper kind anti degree. It is exploded by any violent explosion either in it or into it, Twhether of gunpowder, fulminate, nitro-glycerine, giant powder, or other violent explosive. Such an explosion involves the peculiar percussive pressure and heat necessary. The burning or flashing of gunpowider lunconfined is not sufficient. Another metllod of exploding it is to set it on fire while under confinemlent ill some tight and strong vessel. The burning of the porwder produces gases which, finding no escape, at length cause a pressure so great as to produce, with the heat of the burning, an explosion of the unburned powder. By tight and strong vessels is meant iron retorts, quicksilver flasks, gas-pipe, with caps screwed to its ends, and the like. A vessel of the strongest tin has not the requisite strength; this, like cartridges of paper, ordinary packing-boxes, barrels, casks, &c., will be burst asunder by the gases before the pressure is sufficient to cause explosion. These are the only known fmeans of causing an explosion proper, but a partial explosion can be produced by causing a very thin layer of powder to be struck with great force between hard and smooth surfaces, as, for example, striking a mninute quantity with a hlammer on an anvil, or driving anl iron plug upon it in a hole drilled in the iron. In these cases, a slight explosion andt detonation follow, but not of sufficient force to explode any part of the powder present, except the few particles in immlediate contact with the impinging surfaces. Utenisils for blastind.-Except in special cases, it is better to use the powder in the fornm of cartridges. It is more economical in both tilne and powder, and the explosion is more certain. Cartridges of various sizes are prepared and sold by the conmpany. Should others make them, let it be done with strong material, well glued or pasted together, and let the powder be very firmly pressed into them. Cartridges mnay be cut into such lengths as may be required, care being taken to prevent the loss of powder by rolling the sections in additional paper, or otherwise. Ordinary blasting fuse may be used, but to make sure of a discharge in all cases, and to keep the powder from being burned by fire fromn a leaky fuse the best gutta perchla fuse is recommended, and of a size to fit the caps precisely. Caps manufactured for the special purpose of exploding giant powder are furnished by the comlpany. Common percussion caps cannot be used. As these special caps are more heavily charged with fulminate than ordinary.ones, corresponding care should be taken in their handling and use. A pair of cutting nippers, with their edges blunted, used in securing the caps tightly and firmlly to the fuse. A tube with a fuinnel mouth will be nseful in charging with loose powder. Tin tubing in sections may be useful in guiding cartridges into submarine bores. Drill 7oles, chlarges, 4-c.-As to the dinmeter and depth of holes, and where they should be made, and the direction they should take, and also as to the quantity of powder to be used, and many other matters, no definite or arbitrary rules can be laid down for blasting with any explosive. In these things there lmust be variation according to the location, character of the material to be blasted, the purpose of the blast, and other circumstances too numerous and complicated to anticipate. Much must, therefore, be left to the good sense and experience of the blaster. The following observations and examples will afford some assistance to a beginner:'As a general rule, the drill holes and charges for giant powtder can be, and should be, USE OF DYNAMITE. 21 comparatively small. Experience has proven that ~ inch octagon steel with 3- pound ha1mm1ers, used by single hand drillers, are best adapted to use the powder to the greatest dvantag.e. H1oles one inch in diameter are abundantly large for all ordinary heavy work; for light work, correspondingly smaller ones should be made. A small quantity in a deep hole, whether the hole is large or small; also, a small quantity in a large hole whether the hole be deep or shallow; also a large quantity in a small but deep hole; also, a large quantity in a large but shallow hole, are all examples of misapplications; they are all violations of the general rule applicable to all explosives-that the quantity of powder should not only be proportionate to the resistance, but the hole should be proportionate to the powder. As by reason of its quickness giant powder in bore holes is nearly as effectual without tamping as with it, it can be exploded with great advantage without any tamping at all in natural fissures and artificial cracks. It is therefore urged that advantage be taken of this extraordinary quality as often as practicable. Owing to the great difference in the cipacity betw-een the old and new powder, tihe tendency will be to overcharge; it is therefore recommended that each blaster experiment on this point, so f ri at lea st as to ascertain the minimum quantity of powder which will answer Ihis particular pnrpose. 1Exampjles.-A solid cast-iron ball, seven inches in diameter, clarged with half an ounce of giant powder, in a three-qcarter inch hole, three inches deep, without tamping, will be blown into small firagnients. The same result will follow the explosion of three-quarters of an ounce at the center of a wrought iron anvil. A six foot cube of solid granite charged with an ounce of giant powder in a three quarter inch hole, nine inches deep, will be cracked into several pieces. Boulders three or four feet in diame-' ter, and particularly flat ones, can be cracked in pieces by explQding an- ounce or two of powder on their surfaces. An ordinary rifle will be blown to pieces by a charge of giant powder of one-half of the weight of an ordinary charge of gunpowder. A charge of f'rom one to two pounds of powder in an inch hole from five to ten feet deep, placed ten or fifteen feet back from the face of the wall, in hard rock, will crack off or shatter the whole intervening mass. Charging. —The charge in the forin of cartridges must fit and fill'the bottom of the bore, and be packed solid. Thlis is an essential prerequisite to an effective blast. The best way to secure it is this: Take a cartridge, as near as possible, of the same size of the bore and cut it into sections front one to two inches long' With a hard wood ramier, as longc as will run freely in the hole, press these sections into the bore hole one by one with suficient force until each section is driven to the bottom and expanded laterally, so as to fill the hole solidly in every direction. Any sized ceartridge may be used, provided it is thus put in. Metallic ramimers must not be used. In wet holes the sections of carltridge should be rolled in additional paper, and the ends closed to prevent the powder fi'on getting mixed with water. In many mines the giant powdcr is used loose in downward holes. It is poured through the funneled tube into the tdrill hole. Economiy requires that the tube should reach to near the bottom of the hole. The charge should be rasmeimed d own in divisions, substantially as directed as to cartridges. Prhimfing.-After chargino the bore, cut off' a proper length of fuse and insert its end into one of the speicial capis up to the fulminate. If the fuse is too large for the cap pare it to a fit; if too small, iwrap it with paper. But the difference between the size of the fuse and the caps should be very slight. Then place the edge of the nippers.across the cap near its edge, and iiinlenit it firmly into the fise. Never do this with the teeth. Now cut off about one inchs of the smallest sized cartridge, and roll it in additional paper, and insert the cap with the fuse attached into the powvder about the length of the cap, and press the powder firmly about the cap. Then c:lose the neck of the cartridge about the fuse, and fiasten it there by a strong string, or soume other mea-ns, in such a mainner as to prevent the cap from bing x withdrawn from the powder. To make sure that the cap and cartridgoc do not get apart, it is better, in all cases, not only to tie the cord ibont the niieck, but also to tie the ends afterwards around the naked filse lose to tthe moith of the cartridge. This is called the primer. Thus prepared, plaie tile primner in the drill ho(e, and press it with the hand o: a, wooden rod into contact xw ith the cliarce. In using loose pow(der, if it is within reach of the hand, instead of usings a primer a capped fuse can be used to explode it, taking care to press the powder around the cap, and secure the fuse in place by putting a stone upon it, or otherwise. T'acnWing. — After prilming, fill the bore hole with xwater whenever it can be done, and when it cannot, blast wi. h1out tamnping. Considering the slight advantage of any other than water tamping, the time taken to apply it, the danger of disturbing or exploding the cap, and the inconvenience of repriming in case of miniss-fire, it is better not to use it. Explosion of blasts. —The burning of the fuse explodes the cap; the explosion of the cap explodes the priner or chargei in which the cap may be. All the other cartridges, or charges in the sane hole're exploded by the first explosion of powdcr. 22 MECHANICAL APPLIANCES OF MINING. In case the blast misses fire, put inl another primer. A space of several inches, either vacant or filled, between several charlges or cartridges in the same hole, will not prevent the simultaneous explosion of all. In case the blast is not effective, it will be because our directions have not been followed, or because the blaster has erred in some matter left to his discretion. Tile most comnilon causes of failure are deficiency of powder and defective ramming. It may be stated here that the great advantage claimled for this powder consists not so lmuch in diminishing the cost of powder as an item of expense as in diminishing the cost of using it. The difference in the cost of powder is trifling in comparison with the difference in the cost of drilling, charging, talllping, convenience in wet work, anti effectiveness of blasts. Giant powder, as a general rule, throws rock less and b)reaks it more, and extends its effects mluch deeper than ordinary blasting powder; and those who ruse it soon learn not to judge of a blast by first appearances. It frequently ha]ipens that a blast which seems to have had no effect proves to hllave done renarkable execution in cracking and loosening the rock, and preparing the way for subsequent blasts. This is especially the case in tunnels and shafts. Blastin/g lcder water.-Cartridges to be rused in water should be mnade of such paper as will not be destroyed or materially weakened by the water. Tlley should also be weighted with sand ii their bottoms, or in sonle other way, so as to sink. To use suche as are not thus weighted, in water, they mlust be forced to their places, and fastened there by pouring sand upoiin them or otherwise. In submariiie worki, whelle the bIore is at a considerable distance below the surface of the water, the tubing, in sections, call be used to guide the weighted cartridge to its place. If submerged rocks have to be removed, all that is required is to take a large or small box of giant powder, in bulk, as the case may be; bore with a gimlet a hole into tile box; fasten, as before mentioned, the cap well to the fuse, and push the cap through the hole its length into the powder, never further; tighten the gillllet hole with some grease or wax; tie additional weight to the box, light the fuse, which only requires sufficient length to allow the box time to reach the rock when sunkl, and drop the same on the rock to be blasted. Somie use special submarine fuse, which withstands tile pressure of the water to any depth. In this way the entrance to the great San Francisco dry dock has been cleared firoir rocks, under the superintencdence of the late efficient enginieer, IMr. Pollock. As mulch as one hundred and twenty pounds of black powder at one blast were lowered, nmore than once, on a certain rock near or in front, of tihe dry docek and exploded, and nothing was effected but throwing up a beautiful colulmn of water. Mr. Pollock sunk onI the saine rock a box with ten pounds of giant powder, and the first blast shattered the rock to pieces. Six-pound -boxes were then used, Mr. Pollock fearing the enornous effect of larger blasts might injure the dry dock proper; even these blasts proved too powerful, and at last only twvo-pound boxes were nsed, which siccessfully removed all thle rocks. Temjlleratrle.-Below 42 degrees Fahrenheit giant powder freezes, land above 212 degrees (thlle boiling point of water) it throws off' noxious fuimes, anld becomes weakened and finally destroyed. It should, therefore, be kept in somle place halriir a toeimperaturre between these extremes. When frozen, it can be thawed by beingl kept; foir, time ii this proper temperature. When it becomies soft to the touch it is enady for use. As it fieezes very slowly, no inconvenient haste is required in its application. If the powder in boxes or cartridges has front accidental causes becomee wet, if dried agotail slowly its usefulnress is not impaired. Effect of the gianlt powder o01 tthe heactlh.-Somue -i-iners snlifered frolm hleacidichle ilienii tliis powder first came into use; but this was caused by the imnpossibilitny of procurrilg the raw material at the beginning of the business in a pure state. This has lon1g ago been obviated, and since that time we hear of no complaints of headache, except produced by some of the following causes. We have numerous affidavits from millnes tlhat it never affected them, and that they inever suffered any headache fronl its use. The causes which can produce a temporary headache are thie followilng: Either froism handling the powder too much, tasting it and rubbing it between the fingers, and afterward unconsciously rubbing tile face with the hands, when nlot used to it, or from going immediately after a blast into a badly ventilated tunnel or shaft, which is invariably done by new consuimers, to see the effect produced by this new blasting agent. The enormlous power of thie giant powder in its explosion1 drives away iOr a short while the little good air which is at the end of a tunnel; thie space is then partially filled with gases. In case the charge is not entirely exploded, but part of it burnt, this burning of the p1owder creates the noxious furmes. which cause h1eadacrhe; or t1he fumes are caused by improperly securing the cap to the fuse, and the cap and1 fise to the primary cartridge. It is of very great importance that this should be done proFserlv. Those who are familiar with its use never experielnce any inlconivenienc firom its.use when the whole clharge is properly exploded. A little quicklime placed near the hole to be blasted, or some nmnunia placed in a vessel near the blast, will absorb these.gases in a few minutes. If inen not accustomeil to this powdcler will stay out of the:shafts or tunnels wlich are badly ventilated, after tle blast is exploded, only one-half USE OF1 DYNAMITE. 23 of the time they do after black-powder explosions during the first few days, no conlplaints of headaches w7oulcl evrer arise. It may not be generally known, but it is nevertheless a fact, that if black powder producecd no smoke, (whichl forces men to stay out a certain time,) and they should go in immediately after a blast, they would experience the same headache. This is sufficiently proved by persons of science. The gases liberated by exploding giant powder are carbonic acid gas, oxygen, nitrogen, and steam, and those from gunpowder are the same; but gunponwder, in addition, has carbonic oxide. Pipe-clay baltk blasting.-It has so far been a very expensive operation for the mliners to break up pipe-clay and cement banks to enable them to extract the goldl by sluicing. Long tunnels had to be run, with a T at the end, in which were placed from fifty to one thousand kegs of comlmon powder; the tunnel was then filled -up again and the blast fired. The bank was always thrown over in large pieces of clay or cement, which'were afterwards broken to pieces by picks and gads, and often \with small blasts-a very laborioeus and expensive proceeding. Recently, in this kind of work, giant powder has been introdluced, which overcomes all difficulties, and shows itself so far superior to the old process, and saves so enorlmously in cost, that it cannot fail to be speedily introducedl in all bank blasting, work. In a bank of pipe-clay about seventy feet high a hole six inches in diamleter was bored horizontally, with an auger, twenty-six feet deep and a few feet above the ground. Into this hole one hundred pounds of giant powder, in cartridges six inches in diameter, was introduced and well ra.mmed, and the blast fired. The result was surprisingly successful. The blast did not throw the bank over into enormous pieces to be broken up again, as is always the case where black powder is used; but the blast crushed and crumnbled the entire bank, seventy-five feet on each side of the blast, in'such a manner that when the water is turned on it can all be washed down without additional work. Use ia v~eit m~nininq. —Th e giant powder has been in use for nearly two years at the Oakes and Reese mine, in Hunter's Valley, near the Manriposa Estate. A letter from there, January, 1869, is as follows: We have ulsed the powder entirely since last April. In its use thle steel consumed is of uniform size-three-quarter inch octagon. Hammers (short handles) weighing three and a half pounds. The country rock is hard and tenacious. The veins of quartz are narrowv, varying from ten inches to three feet, generally running from one foot to twenty inches in width, with little or no gouge. The system which Mr. Cassel, superintendent of the mine, has introduced, (and which can only be used to advantage with giant powder,) is to pay the ininers by the foot in depth of hole drilledl-the minler doing no blasting, nor does he handle any rock, his simple duty being' to drill holes where instructed. The underground superintendent or head blaster-one for each shift-instructs the miner where to drill a hole. When the hole is drilled to the depth required the superintendent measures it and takes a memorandum of the same, and sets the miner at work elsewhere. As soon as the hole is measured the blaster loads it with from two to two and a half ounces of loose powder, fills the hole with water, covers it, and leaves it until the men leave it at time of shift. As soon as the men have left the mine, the blaster with his fuses, with cap or exploder attached, makes his round, and, removing the cover from the hole, drops the fuse into the hole, works the exploder into the powcler, which is quite soft, fires the fuse, and in a few minutes will explode all. the holes drilled during the working shift. As soon as the explosions are made the rock men and skip men clear away the debris which may be in the way of drilling new holes, and when the men again come into the mine there is work for them ahead in drilling. A blast is only fired when the men are at work on the mine when it becomes necessary to remove material. Thus it will be seen no time is lost in blasting. My experience since April last leads ime to know the following facts in the use of giant powder as against gunpowder: First. The amount of work which can be performed in a given space in a mIine is nearly double. Second. The consumnlption of steel is about one-half. Third. The consumption of hammers is about one-half. Fourth. The consumption of candles is about one-half. Fifth. The width of the drifts or stopes is only about one-half; requiring so mulch less material to be removed or hoisted from the mline. Sixth. The mining timbers are shorter. Seventh. The ore raised froml the Illine is broken by the force of the powder so as to require less spalling for the mill. Eighth. The progress of the work in the mine is expedited at least forty per cent., and in wet mines the progress is increased fully fifty per cent., if not more. So far as the miner is concerned, lie can earn more money with a three-quarter-inch 24 MECHIANICAL APPLIANCES OF MINING. steel and small hammuer, than in any other -way. It is true lihe mst earn his mlloney, and is not paid by the lay. The price paid in the Oakes & Reese imine is 371 cents per foot of hole drilled. In October, there was drilled 6,4768 feet of hole, costing $2,429 03. The following list will exlhibit the amounts earned by miners most expert in the use of single-hammer drills in October, twenty-seven working days. P. Beicai.. —..$ —-. — -...... --- -$130 20 H. Laity ---—. $ —------—. —----'97 36 L. Boivin ------ ------ - 124 33 F. Gill.-.......-.. —. —-—.. 94 62 J. A. WVilson --—. —--------— 1. 131 77 P. Lastrade ------------—. ---- 90 70 B. Kendall. —------------------ 103 77 J. Fortuna ---------- 94 56 S. Cox1.....2 122 5 1H. Boyle-.91 77 S. Uran —----- 130 74 J. 3Martin - 90 49 B. Picardl..-.. r............. 104 50 L. Battiola --------------------- 84 93 and many others ranging below the above amounts, falling short either because not working full time, or from not being expert in use of the single hammer. Still, any system of mining where a miner willing to work can earn as high as $131 77 per month of twenty-seven working days, must inure to the benefit of the miner, and particularly so when the mine owner is willing to pay such wages. One thing is certain, that with giant powder and the use of small steel and hammers, the miner lmust earn his money, and cannot shirk his work, as is too often the case under the old system of mining. Mr. L. L. Robinson, the president of the Giant Powder Company, writes under date of January 25, 1869, to the Mining and Scientific Press, as follows: EDITORS PRESS: Noticing in your paper of the 16th a communication having reference to the use of giant powder in the Oakes & Reese mine, belonging to Mr. McAllister and myself. I beg to state that during the past week our superintendent, Mr. Cassel, has let the following contracts for work on the mine: 1. Sinking the main shaft 50 feet from the 278-foot level, at $60 per foot-contracting parties furnishing everything. 2. Drift west, on Oakes & Reese vein, 50 feet, at $13 per foot-contractors furnishing everything. 3. Drift south, 50 feet, at $10 75 per foot. The same work has heretofore cost us, with the use of black powder, as follows: 1. Sinking nmain shaft, $90 per foot. 2. Drift west, Oakes & Reese vein, $30 per foot. 3. Drift south, blue lead, $25 per foot. Thus it will be seen that in these three contracts tIhe mine owners save as follows: 1. Sinking 50-foot shaft, at, $30.-$ —-.-... —-—..-... $1, 500 00 2. West drift, 30 feet, at $17-...-............ 850 00 3. South cdrift, 50 feet, at,14 25.-. ----------—... 712 50 Total savinag......, 062 5( In addition to the saving in dollars and cents, is also the important itenml of saving in time, as the time occupied in finishing contracts with giaont powder is only about one-* half the time required with use of ordinary powder. The contractors, even at these low rates, are better satisfied with the prices than under the old prices with the common powder. Giant porwder for railroad iwork.-The Central Pacific Railroad Company, in running their long " Summit Tunnel,"/ commenced the use of nitro-glycerine, and found it so very effective and advantageous that they were enabled to complete the tunnel in over one year less time than if ordinary powder had been used. How much this saving of time of over one year has been worth to the Central Pacific railroad can hardly be estimated. It is well known that giant powder possesses abolut the same strength as nitro-glycerine,. withlbut any of its daingerons qualities. At the time the above work was done, giant powder had not been invented, otherwise it would undoubtedly have been preferred to initro-glycerine. The Western Pacific Railroad Comnpany, the Oregon Railroad Company, and the Virginia and Truckee Railroad Company have used, and are using, the giant powder. In conclusion, Messrs. Bandamaann Nielsen & Co., give the annexed recapitulation of the chief advantages attencding the use of the giant powder: 1. A great economny in labor for boring. 2. The rapidity of blasting operations, which is of vital importance, especially for mines and railway tunnels, can be made with giant powder in one-half the time, or less, than with black powder. USE OF DYNAMITE. 25 3. Perfect safety in carrying, storing, and handling it. 4. A complete combustion, which leaves no smoke or noxious gases. 5. The quickness of explosion is so great that fissured rocks and clay are easily blasted with it. 6. Great saving in wear and tear of tools, and in consumption of steel and fuse, fewer bore-holes being needed. 7. No talmping but water or loose sand being required, the loading is attended with no risk, but with a saving of time and expense. 8. In boulder blasting in gravel claims it is very superior, as in all ordinary boulders, too large to be easily removed by manual labor, a small charge of giant powder in a hole made with a half-inch drill and three-pound hammer, will shatter the boulders so they can easily be handled. 9. Its use under water or in water-bleeding rock is very simple and the effect very oreat. 10. It is very useful for blasting heavy blocks of iron, steel, or metal, which cannot be blasted by gunpowder, but easily yield to small charges of giant powder. 11. For military purposes, in springing mines and removing palisades. A fair trial never fails to prove a complete success. The first blasts are conclusive as to the great superiority of giant powder over gunpowder, but its full economical value can only appear when those who use it use single-handed drills, and at the same time gain experience enough not to waste its power by overcharging or requiring impossibilities of it. The consumption of giant powder in California is reported (1869) to vary from 12,000 to 15,000 pounds per month, and to be increasing. EXPERIMEINTS WTITH GIANT POWDER.-In offering the giant powder to the several steamship, steamboat, railroad, and express companies to be transported, some doubts were expressed as to its safety; invitations were therefore given to several officers of these companies to witness a few experiments with the powder, designed to test its qualities in this respect and satisfy such doubts. Accordingly, on the 27th day of AMarch, l1868, near the company's works in San Francisco, the powder was subijeted to the following tests, in the presence of Charles E. AfeLane, of gWells, Fargo & Co.; C. J. Brenham, of the California, Oregon and 3Mexico Steamship Comzpany; B. M. Hartshorne, of the California Steam zNavigation Company; W. 3M. Hughes, of Hughes & Keys, of Stockton, and several other gentlemen. The following is the record of results:!First Exlerintel.t.-A box strongly made of 41-inch pine boards, and filled with about 3 lbs. of giant powder, firmly packed, was thrown from a perpendicular height of 30 feeupon a rock. The end upon which the box struck was broken in and the powder cont siderably displaced and compressed, but not exploded. Second Expcriunent.-At the suggestion of Mr. McLane, 8 cartridgoes, each containing 4 ounces of powder, awere firmly bound together with a strong cord and thrown repeatedly from the same height upon the rocks below. Several of the cartridges were indented, bent and bruised, but not broken. Finally the cord was cut by the rocks and the cartridges separated. No explosion. Third Expeerilment.-A similar bundle of cartridges was placed upon a large rock, with a rough surface, and heavy stones, weighing from 10 to 30 lbs. each, thrown fiom the same height upon it. The cartridges were flattened and broken open, and some of the powder spilled and ground into the rock. No explosion. Fomulth Experiment.-A box of the saime size as in the first experiment was filled partly with cartridges and partly -with loose powder. A common fnse, without any ca p, was inserted in the loose powder, and the cover of the box screwed on and the fuse lighted. The loose powder was set on fire, causing a formation of gases, which forced the boards apart, and escaped with a hissing noise like steam. There was no explosion. The loose powder was burned while the cartridges were unaffected except by being scorched. In this state one of the cartridges was taken from the box and exploded in the ordinary manner, with terrific effect. Fifth7 Exp2eriment.-A similar box was now filled with cartridges, fiom which Captain Brenham selected one at random, for the purpose of testing it. The box was then closed tightly, and placed upon an open fire and consumed, powder and all, without exploding. During the burning, slight noises were heard from time to time, indicating the bursting of the cartridges. The cartridge selected by Captain Brenham was now exploded in the usual mnanner, with the usual effect. Sixth, Experimelt.-A heavy tin cylinder, 1 inch in diameter and 8 inches long, was packed full of loose powder, a fuse without a. cap inserted, and the end of the cylinder 26 - MECHANICAL APPLIANCES OF MINING. then tightly plugged. A small portion of the powder about the fuse wats burned, the plug forced out with a noise like the drawing of a cork, and the fire extinguished. The cartridge was then thrown into a fire and consumed without exploding. Seventh Experimnentt..-Six cartridges, each containing 4 ounces of powder with a. capped fuse in one of them, were placed 2 or 3 inches apart in a horizontal crevice in a cliff of hard rock, without tamping or other means of confinement. The cartridges were all exploded together; there was but a single report. The bluff above the crevice, to the extent of many tons, was completely shaittered. Eig7ht7.E xlei Exeriezt.-The box of powder used in the first experiment was now placed on a flat, hard stone, about 9 square feet surface, and fifteen inches thick, and exploded in the proper manner. The rock was broken into fragments, none of which was larger than a man's fist, and the ground was torn up and blown out to a considerable depth. Xinlth Expeinmenlt.-Two handfuls of loose powder were exploded lupon a rock similar to that in the eighth experiment, but imbedded in the earth. The portion of the rock above ground was crumbled into small pieces, while that below was cracked and shivered in every direction. Tenth EL peaeerimnet.-A section of 2-inch comlmon gas pipe, about 4 feet long-, was placed npon the ground, a 2-ounce cartridge inserted loosely in each end, leaving the tube between the cartridges —a space of about 3~- feet-entirely empty. In one of the cartridges was placed the usual fuise and cap and nothing in the other. No tamping was used, or other filling or fastening. The ends of the tube were not more than half filled by the cartridges. Both cartridges exploded at once. Each end of the pipe for about a foot was blown off, and into small fragments, leaLving half of the remainder split open and flattened out as by a hammner, and the other end flaring and jagged. DUALIN. Another powerful explosive colmpounid has recently been brought before the public and patented in the United States. It is known as duain aindcl appears to be a mixture of nitro-glycerine and nitrogenized cellulose, made from sawdust. It was first introduced into Germuany in April, 1869. In many mllining districts, especially in milnes belonging to the Prussian government, it is now used in the place of common powder, and has taken the place of nit ro-glycerine and dlyna,mlite, (giant powder.) Lieutenant Dittmnar, the inventor, and the lmanufacturer of the article at Bost;on, describes dualin as a powder: It is fabricated in six different degrees of strength, the use of which will depend oin the degree of hardness and toughness of the material intended to be subjected to the action of the powder. Dualin will, if lighted in the open air, burn without exploding; but, if confined, may be made to explode in the same way as common powder. It is not sensitive to concIssion; will not decompose by itself, nor cake or pack together, and may be readily filled into cartridges or blast-holes, requiring no other than watertamping. It matters not whether the place where it is stored be warm or cold, dry or damp. Dualin has from four to fifteen times the strength of common powder, and is, therefore, stronger than nitro-glycerine or dynlamite. The advantages claimed for dualin over other explosive agents areFirst. It may be stored, transported, mlanipulated, and -applied with less rislk thlan common powder. Second. It may be used in cold weather without first requiring the warming process,,which nitro-glycerine and dynamite require, as they frequently become inexplosive' at a low temperature. Third. Its explosion does not develop any noxious gases. Fourth. Absolutely cheaper than either nitro-glycerine or dynamite, dualin is also relatively cheaper than common powder, for, possessing four to fifteen times the strength of the latter, its use will proportionably reduce the labor and cost of mininog and blasting operations. Fifth. The effect of a dnalin explosion is to tear and rend the material exposed to its action, less than to pulverize it, as is the case with nitro-glycerine when applied to mining and blasting operations in coal and rock. Sixth. DuaLlin, when confined, does not necessitate the application of an exploder, but may be exploded by a blasting fuse, like common powder. Seventh. Its great want of sensitiveness to concussion, renders dualin a suitable material for the bursting charge of shells. Eighth. Dualin may be stored for long periods without losing any of its strength. Ninth. Dualin may for days be subjected to the action of water without losing any of DITALIN. 27 its strength. Tin cartridges are, therefore, never required, not even for submilarine blasting or blasts where water-tamping is used; and in shipping dualin packed in paper or thin wooden cartridges, ready for use, the only object is to save the consumer time in charging his blast. Dir'ectioIs fo0r tuse. —Dualin is shipped in boxes containing the cartridges, all ready for use; the degree of the powder, the number of cartridges contained in each box, the weight, diameter and length of each cartridge being plainly marked on the box. 1. The common blasting fuse may be used whenever rock, sand, brick or clay is used for tamping. In this case the treatment of dualin is entirely analogous to that of common blasting powder. 2. Exploders are required for firing charges. A. When no blast-hole having been drilled, the powder is simply placed on the surface of a boulder, &c., which it is intended to break. B. When submarine blasts are to be made, or water is used for tamping, or the blast,holes contain water. C. When electricity is employed as a means of igniting the charge. For heavy charges it will be well to use more than one exploder. The effect of the explosion depends greatly on the cartridge exactly fitting the blast-hole. Whenever ordinary tamping is used it should be packed as compactly as commontpovcer repuires. Blast-holes that will hold water require no other but water-tamping). i MBr. F. Shanly, the contractor upon the Hoosac Tunnel, has had some experiments tried with dualin at the tunnel, and certifies that he has used about 20 pounds, mnanufactured by Lieutenant Dittmar, and, so far as an opinion could be formed upon so limited a quantity, he considered it fully equal to nitro-glycerine in its results, while for safety in handling, it was proved by the most severe tests to be vastly superior. In several of the blasts water-tamping was used. The charges were fired by means of electricity, using aMr. H. Julian Smith's battery. The same battery has been il service for some time past, in, the operations of the Hoosac Tunnlel, and it is but just to state that in regard to the density of the spark developed, as well as to simplicity of construction and compactness, a more serviceable battery could hardly be recomrmended to the attention of all engaged in mining or blasting operations. Tlhis battery will be described in a future chapter. Another coinpound l called xyloidine is mlanufactured at the same establishment. The Journal of Applied Chemistry observes as follows in respect to the qualities and strength of (lualin: This compound, whbich, according to its inventor, Mr. Dittmar, possesses the explosive power of nitro-glycerine, together with the slow combustibility of ordinary gunporwder, consists principally of nitrate of ammonia and fine sawdust, that has been acted upon by nitro-sulplhuric acid. Thils material, according to Fuchs, is undoubtedly endowed with a greater explosive force than ordinary powder; it is also considered as being less dangerous in regard to spontaneous explosion. In its composition it is similar to that of gun-cotton. being also subject to gradual decomposition in moist air. In regard to the efficacy of the dualin, as compared with dynamnite, (which is a mixture of nitro-glycerine and infusorial sand,) the inventor states that they are both equal in this respect. However, it is extremely difficult to get at comparable resultrs in blasting experiments; in most instances, the experimenter must be satisfied with the average results of a great number of trials undertaken under various conditions. But it is nevertheless easy, in one respect, to fix a difference between the two materials, which leaves no doubt as to the superiority of the dynamite. If equal quantities of dynalnite and dualin, provided with primers, are allowed to explode upon air plates of equal strength, the effect indicates such an evident difference that one must adjudge to the former a much more rapid and violent action. This will certainly be recognized in blasting rocks. In price dualin is cheaper than dynamite. When coming in contact with fire, it will certainly cause explosion, as it burns quite as rapidly as ordinary powder. Of the dynafnite, however, it is sufficiently established that it will never explode on holding a flamue near it, but simply burn quietly, even if inclosed in strong wooden boxes. Against pressure and concussions, both blasting materials are equally inert, and, finally, dualin possesses the advantage over dynamite that it does not freeze, while the latter, when in a frozen state, cannot be directly exploded. But as blasting is mostly suspended during frost, this circmnstance is not of very great importance; moreover, the use of dynamite is not excluded at all, if frozen, as it will readily yield by the explosion of a small cartridge containing non-solidified dynamite. The great superiority of dynamite, above all, consists in its non-liability to become 2 8 MECHANICAL APPLIANCES OF MINING. moist; this property allows its direct application under water and in bore-holes, while dualin, like gunpowder, does not bear contact with water. The objection thus urged aggainst dualin is contradicted by the inventor, who declares it to be insensitive to moisture. PYlROXYLINE, XYLOIDINE, GUN C(OTTON. The name pyroxyline is given to the very inflamimable and detonating compound produced by the act.ion of concentrated nitric acid upon cellulose, or substances such as cotton, linen, hemp, paper, and, sawdust. The name xyloidine was given by Braconnet, in 18337 to the wAhite, pulverulent, and very explosive substance he had obtained by treating starch with many times its weight of concentrated nitric acid. The preparation of gun cotton for imining purposes has been greatly improved. It is now made into pulp, and then compressed into solid cylinders, which burn harmlessly when ignited in the open air, but explode with intense violence when confined and ignited by a detonating compound. In its old form, it was experimented with at the Gould & Curry mine, in Nevada,, with apparently good results. A report of these experiments states that a 11-inch hole, twenty-eight inches deep, in hard and tightlybound rock, charged withl six inches of cotton and exploded, threw down as munch rock as an ordinary charge of gunpowder, without producing any snmoke. OLIYERIS POWDER. A new powder-, Iunder the above name, has been manufactured near Wilkesbarre, Pennlsylvania, for some months past, by the Luzerne Powder Company, a corporation organized by some of the principal coa1 operators of that region. It is believed that the invention is calculated to be of great public benefit, by reducing the risk and danger in the manufacture of powder, and by producing, at the samne time, a safe and powerful explosive. General Oliver's patents refer to both the ingredients used and to the machinery employed in the manufacture of the powder. In composition, the principal difference between this and otherpowders is the substitution of peat for charcoal; and this, together with the method of manufacture, produces an article which, it, is claimed, has invariably shown, in the "' powder prover," a strength from twenty to thirty per cent. greater than that of Dupont's, Hazard's, Smith & landcl's, or any other powder now in use in the coal region. The sporting powder of the Luzerine Powder Company, as compared with the finest brands of rifle powder, is stated to give a much higher velocity, and consequently a greater penetration to the ball; to foul the gun. less; ancd like the blasting powder, to produce less smonke than do the powders now in use. The machinery used in the nmanufacture is very simple and inexpensive, and only a very snmall quantity of powder is at, any one time in the mill, and that, while unconfined, is inexplosive. The success,attending the manufacture by the Luzerne Powder Compa ny has been suffic(ient to induce the company to determine on building' a second mill near 1Hazleton, Pennsvylvania. Another substitute for charcoal, which has been tried with favorable results in the manufacture of gunpowder, is the mineral known as Grahamite, and occurring in WTest Virginia. Its application for this purpose has been paltented by Dr. Van der Weyde, of New York. FIRING CIIARGES BY ELECTRICITY. 29 CHLORATE OF POTASH POWDER. A so-carlled " safety explosive compound," has been patented in England, by Mr. Percy A. Blake, of Aberdeen Park. The constituents of this compound are sulphur and chlorate of potash, in the ratio of one of the former to two of the latter. These substances are kept separately anlc dry, and are mixed when required. The powder burns slowly when ignited, but explodes under percussion. This explosion is effected by means of a detonating tube of metal, about an inch long and - of an inch in diameter, partly filled with the coinpound and with fullninating mercury, and lastly with powder. This powder may be ignited by any ortdinary ignition apparatus. The first attempts to makle powder with chlorate of potash, sulphur, and carbon, were those of Berthollet, in 1788. In 1792, experiments in its manufacture were made at the works of Essonne under his direction; but they were stopped by a terrible explosion which (destroyed the lives of the director of the works, his daughter, and four workmen. Berthollet, who was with the director, had a wonderful escap)e. The explosion was caused by the end of the director's cane striling some of the powder upon the floor. It has also been attempted to use various mixtures of the chlorate with. white sugar and prussiate of potash and with charcoal and sulphulret of antimony and starch; but all these compounds are exceedingly dangerous to manufacture or transport, and it does not appear probable that they can ever come into general use. For mining purposes a mixture of tan-bark, chlorate of potash and sulphur has been made at Plymouth, England. The tan is soaked in a warm solution of the chlorate, and afterward covered with a fill or layer of powdered sulplhur. This preparation is said to burn but slowly in the open air, but when confined, as in the hole of a boring, it explodes with great energy. Picrate of potash has also been experimented with, and used for torpedoes, but its preparation has led to some frightful accidents; that at the Sorbonne, in 1869, killing five persons and wounding imany more. EXPLODING CHARGES BY ELECTRICITY. Franklin, in 1751, and Priestley, in 1761, suggested the possibility of -applying the electric spark for the ignition of gunpowder charges; but electricity was not practically applied until about thirty years ago, by the French military engineers, since which its use has become genera]. It was employed to ignite the great blasts that destroyed the PRound Cliff at Dover, and to remove the wreck of the Royal George; and has been largely used in heavy blasting with powder and nitro-glycerine in California and for exploding torpedoes -under water. The variety of contrivances is very great. Many exploclers have been devised to act either by heating a piece of thin wire, introduced in the circuit of. a battery and placed in the charge, or by the passage of a spark produced by an electro-ma, gnetic miachine or Ritchie coil through a sensitive explosive compound, thus causing a local explosion sufficient to ignite the whole charge.' Among those who have given great attention to this subject, Baron Von Ebner, of the Austrian military engineers, may be specially mentioned, and Mr. Abel, of the British war department, who has devised one of the best explodlers known. A spark generated by revolving magnets is made to pass through a mixture of subphosphide and sub 30 MECHANICAL APPLIANCES OF MINING. sulphide of copper and chlorate of potash-lmaterials of high conductinog power and extremely sensitive to the spark. One of the great difficulties in the w ay of making such exploders is the liability of the nmaterials to be rmerely thrown aside and not exploded by the passage of the spark. In th-e United States inventors have been active in devising different forms of apparatus for igniting explosives. They all depend npon either the direct passage of a spark or the heating up of an imperfect conductor, immersed in an explosive mixture. This mixture and the arrangement of wires are inclosed in a, small cartridge of paper or wood, which can be readily placed in the midst of the powder in the hole to be exploded. AIr. Stowell patented, in 1862, a, peculiar form of cartridge containing the ends of the conducting wires and a strip of platina. Beardslee, in 1863, patented a very simple mnode of making an imperfect conductor between the ends of two wires, by drawing a pencil mark, of graphite, upon the surface of a piece of dry wood. Mowbray, in July, 1869, patented an improved electrical fuse for exploding charges of nitro-glycerine. It consists of a small cartridge of powder, in the top of which is placed a small quantity of a composition, like that used by Mr. Abel, made of sulphide of copper, 9 parts; subphosphide of copper, 2 parts; chlorate of potash, 3 parts, the whole intimately mixed. The ends of the wires are immersed in this mixture. It is designed especially to be inserted in cans of nitro-glycerine, to be exploded inl oil wells. The dealers in the new explosive compounds, such as nitro-glycerine, dynamite, and dualin, furnish exploders especially designed for the several preparations. These various explolers may be fired either by the voltaic current or by a spark from a suitable electrical machine, or the Page coil. An electrical machine has recently been invented and patented by Mr. 1H. J. Smith. The following is a description and the claim': The object of tlis invention is the production of an electrical machine constructed with especial reference to portability, and to working in all conditions of the atmosphere. It is designed more especially for igniting charges of powder by means of thle electric spark which it evolves. It is well known that the electrical machine, as commonly constructed of glass, becomes wholly inefficient in a damp atmosphere, such as prevails in tunnels and mines. This is due to the fact that glass so very readily condenses moisture upon its surface, in the form of a continuous film. Vulcanite, on the contrary, does not so readily co-ndlense moisture. Nor does it condense moisture in the form of a film, but rather in the form of detached drops. The machine consists of an outer covering or shallow box, containing a frame plate, a Leyden jar or condenser, a generating plate of vulcanite, and devices for operating the generating plate and condenser in connection. The frame plate, the condenser, and the generating plate are placed parallel to each other, and parallel to the sides of a box about a foot in diameter. The condenser is connected to the frame plate by four posts, 1, 2, 3, and 4. The generating plate of vulcanite lies between the condenser and frame plate, and is revolved on its axis by means of a handle or crank. The axis of the generating plate passes tightly through a stuffing box, wrhich may be made to grasp the axis more or less tightly, by means of a paicking screw. The outer end of the axis has its bearing in a small hole sunk in the outer vulcanized plate of the condenser. The generating plate of vulcanite revolves between two cushions, the surfaces of which atre coated with an amalgam, as is usual with electrical machines. The cushions are provided with flaps, which flaps serve to prevent the electricity from escaping from the generating plate until the excited portion of its surface arrives in the neighborhood of the collectors, which are serrated strips of metal, placed one on each side of the generating plate, and both collectors are attached to and in metallic' Vide letters patent, No. 93,563, August, 1869. FIRING CHARGE1S BY E LECTRICITY. 31 connection with the frame post 4, and by it are brought illto coinnection with the inner plate or surfice of the Leayden jar or condenser. Tlhe two outer plates or snreaces of the condenser irc in mletallic colnnetion with the post 2, and al.so with thle cushions by means of post 3. The inner plate connects with post 1, as well as w-rith post 4. The condenser is constructed in the following Launerr: When the vunlcanit is in a plastic state, upon a layer of lvucmllite is placed a layer of tin-foil. Over the layer of tin-foil there is placed a second layer of plastic vualcanitc,,m[id then a secoind layer of tin-foil. A third layer of plastic -vulcanite, a third of tinl-foil, and a fourth of vrulcanite, complete thle jar or condenser. The first anid third layers of tin-foilfoidin the o(nter sulrfi es of the condenser, the middile layer forming the inner surface. Care amust be takeln that the diameter of thle tin-foil plates be less thain that of the layers of plastic rubber, excepting a small projection from each tin-fobil plate, intended to connect -with the posts of the framlie. The condenser, thus made iup, is then submitted to the baking- or vulcanizing process, at the end of which it becomes hard and rigid. Its surfaces will forever remailnn a perfectly dry condition. The posts 1, 2, 3, a nd 4, are now sci ewed into the condeniser, posts 1 aliid 4, as before stated, connecting with the inmer surface, while posts 2 and 3 connect withl the outer surfaces. To the outer casing are attached two knobs. Thlese knobs are electrodes, or paths tor the discharge of the electricity -when they are brought into contact with the inner and outer surfaces of the condenser, vhich is done by turning the handle of the machine backward a little, -until the post 1 comes into contact witl a projection from one knob, and the post 2 cornomes iito contact with the projection fiom another kniob. There is a stop, which serves to prevent the framework of the mnachine fiom revolving by the action of the crank, except through a small arc. The post 1 is limited in its forward motion by the stop, and in its backward motion by the projection from the knob. The casing is made of vulcanite. Two forins of casing are imade: one, a box in halves, which are screwed together-, with a packing of soft rubber or other air-tight material between themn; the other, a box with a cover, having 2 rubber band placed over and around the outer edge. The operation of the machine is as follows: By turning the crank the generating plate is revolved betwveen the cushionis. The electricity generated is collected by the collectors, and from them carried by post 4 to the inner surface of the condenser. The opposite electricity appearing at the rubbers, is conducted from theim by post 3 to the outer surface of the condenser. By continued turning of the crank, the condenser may be charged sufficiently to give a spark of three-eighths or one-half ani inch in small machines of five or six inches in diameter. The first motion of the crank turns the fraime, as well as the generating plate, luntil post 1 strikes the stop. Turning the crank backward brings posts 1 and 2 in contact with the knobs, when the condenser may be discharged. It is desirable that the con(lenser be discharged by the posts 1 and 2, rather than by posts 3 and 4, which are used for charging, as the tendency to escape during accumulatioln is thereby avoided. The framlre plate a:ld the generating plate are both made of plastic rubber, and vulcan ized. The capacity of a Leyden jar or condenser constructed of plastic rubber and metallic plates, as above directed, may be increased by adding successive layers of metal and vulcanite. Such a condenser will be of use for electrical purposes independently of the generating apparatus herein described. The inventor claims: 1. A generating plate and a flat condenser, placed parallel to each other within the same casing, substantially as described. 2. A Leyden jar or condenser constructed of vnllcanized rubber and metallic plates, substantially as described. 3. So arranging the jar or condenser that the forward motion of the crank, to generate electricity and charge the jar, moves the jar forward through a small arc, whereby its terminals are moved away fiom the discharging knobs. 4. The device for discharging the jar by the retrograde motion of the crank b'ringing the posts 1 and 2 into contact with the projections from knobs V aIld W. 5. Placing the firing points of the condenser at a distance from the collecting points, substantially as described. 6. The stop X, limiting the forward movement of the jar, substantially as described. 7. The combination of a generating plate, a condenser, and a casing, made air-tight, as described, by packing or a rubber band, together with knobs in the casing, and their projections, by which the condenser is discharged, substantially as described. SECTION II.-BORING AND EXCAVATING BY MACHINERY. CHAPTER IV. MACHINES FOR DRILLING ROCKS. 1Iachines for rock-drilling originated in the United States, where one was put into practical operation as early as 1838. The attentionl of mnechanicians and inventors being thus early directed to this great desideratum, a machine that could be economically and easily substituted for hand labor, so great a variety of contrivances and forms have been proposed alnd experimented with, that their number renders it difficult even to enumerate them. Our Patent Office and the patent offices of Eulope contain many models of machines; but most of. them are of the class known as "' drop drills,' where the tool cuts by percussion. There are other forms of machines, fitted with revolving disks or cutters, and designed to bore out the drift or tunnel to its hill size at one operation; and others, again, in which a nunmber of drills are mlounted in a, fralne, so as to cut an annular space around a central core of rock, Nlwhich can afterward be broken out with powder or otherwise. There is still another type, in which diamonds are mcade to- do the cutting by priessure alnd rotation, without percussion. IRock-clrilling imnachines may therefore be grouped in two great classes: 1. Those that bore by percussion; 2. Those that bore by constant pressure and rotation. The drop drills belong to the first class, and will be first considered. In these mac-hines the drill or bar of iron or steel-,either a siungle rod or provided with a steel bit, or point at the lower end —is raised by means of a crank, cain, or other mechanism, and then allowed to fabll by its own weight lupon the rock to be bored. There are also numerous contrivances to accelerate the speed of the fall and increase the force of the blow. Metallic and ru7bber springs have been used, ancd, in somne cases, the elasticity of air; but in all these modifications but little has been gained over thle for in which gravity, acts unaided. WXith springs, the greatest compression and force is exerted when the drill is at its higlhest or furthest from its striking point, and as the drill descends this force becomes less and less-the reverse of the most desirable condition given by gra vity. It is desirable to note a few of the more important of these inventions which have been in use practically during the past thirty years, and which, by successive rmodifications and illnprovemlents, have led to the present y ery considerable degree of perfection of rock-drilling machines. As early as 1838, Messrs. J. N31. and John IN. Singer experimented with a large drop drill on section 64 of the Illinois and Michigan Cainal, about thirty miles below Chicago. This machinle-was patented in M'Iay, 1839, and some ten or twelve machines were built for, and used upon, the canal until the suspension of that work in 1841-'42. They were also used in the Mount WTashington cut, near Hinsdale, for the WVestern railroad of Massachusetts. Two machines were built at Lochport, in 1840, and used upon the enlargement of the Erie Canal. Modifica3M 34 MECHANICAL APPLIANCES OF MINING. tions of these machines are even now in use in various parts of the country. They are all drop drills, and' their operation is restricted to vertical holes. The original Singer drill, as applied in Illinois, is considered to have been the first successful -machine for its purpose. It w-as extensively copied, and many improvements upon it were claimed from time to time. The first substantial departure from it was made by J. J. Couch, aided by Josepht W. Fowle, of Boston, in the year 1848. They constructed a steam drilling machine, in which the drill-bar passed directly through the piston of the engine and was alternately caught, drawn back, and thrown against the rock. It was only used a short time in experimenting, and was finally taken apart and sold at auction. Although not a success, this machine marks the second phase of the rock-drilling machines, and was the first attempt that approached success in the direct application of steam-power to rock-drilling. From the time of this experience the two inventors separated, MIr. Couch following up the general idea of a hollow-piston drill, while Mr. Fowle, discarding the idea of the hollow piston, conceived that success would!:e gai:ned by placing the drill directly upon the end of a solid piston-rod. During a period of five years M3ar. Couch produced a iunimber of drilling engines, wtariously constructed: but all -upon the hollowpiston plan. Some of these were in a, measure successful, but not sufficiently so to insure their general adoption. They required very nice adjustment and presented practical difficulties; and finally this style of machines was abandoned. Mr. Fowle, adhering to his plan of attaching the drill directly to to the piston-rod or cross-head of an engine, experimented and struggled against many obstacles for several years. He built, in all, some five machines, but did not succeed in carrying his plan to perfection, until, discouraged and disabled by sickness, he suspended his efforts. In the year 1861 machine drilling was experimentally begun by Somlmeiller, at Mont Cenis, with machines virtually upon the principle of Fowle's, though different in construction. To AM. Sommleiller belongs the credit of driving such machines with compressed air, a very important application of this power for all tunnel or mining work, especially where artificial ventilation is required. The magnitude of the undertaking to tunnel the Hoosac Mountain, in Massachusetts, upon the line of the Troy and Greenfield railroad, prompted the commissioners having it in charge to seek all means of accelerating the work, and their attention was naturally directed to the reports of rapid progress by machine drills at Mont Cenis. The report being favorab)le as to the results, while the machine of Sommneiller was not regarded as specially adapted to the work on the Hoosac Tunnel, it was decided to devise and perfect a drill for the purpose. As a first step, Couch's patent of the hollow piston-rod was purchased for New England, and scientific mechanics were employed to work upon it. One of these machines, constructed by Mr. Hanson, is known as the HANSON MACHINE DRILL, which promised some success, but on trial proved a failure. It had a cylinder and valve-motion, similar to those of a steam-engine. The piston was hollow, with the drill-bar, of any required length, passing through it and moved by the piston, by means of four wedges or cams at each end. These cams were pressed upon the drill-bar by means of sliding collars, forced upon them by a complex arrangement of mechan MACHINES FOR DRILLING ROCKS. 35 is5l, acting alternately upon one and the other, for the purpose of catching and throwing the drill-bar. The rotation of the bar was effected by means of a ratchet, worked by a spiral groove in the shield of the machine. There were 120 pieces in this machine, and it weighed 590 pounds. It did not work well horizontally. The main difficulty was with the canms and collars for seizing the drill-bar. A second machine, called the' BROOKS, BURLEIGHI, AND GATES MACHINE, made under the direction of the commissioners at Fitchburg, was put upon the works and used for several months. This machine also had a hollow piston, the drill-bar or holder being a screw, passing through. the piston and imoving with it. The feed was given by means of a nut on the end of the piston-rod, held by means of a cap or union nut, the latter being screwed OLL to the coupling, and the coupling-nut screwed to the piston-rod. The feed nut turns in the union nut, and protrudes from it. A ra'tchet, moving with the piston, works upon this feed nut, and is governed in its action upon the nut by a spiral groove in a shield attached by screws to the cylinder. On the ratchet band there is a pawl, with two springs, one under the other; one serves to hold the pawl in gear, the other to hold it out of gear. As' the piston descends7 the outer spring comes in contact with a trip on the shield, aLnd is lifted up, allowing the under spring to throw the pawl into the ratchet; and as the piston returns, the outer spring turns the nut round, and thus feeds the screw, or the drill-bar, foreward. At the end of the back stroke, the pawl strikes another trip on the shield alnd is thrown out of gear, and is held so by the outer spring, made with a catch. The rotary motion of the drill-bar is given by a ratchet on the coupling-nut, covered by a ratchet band, the arm of which. moves in a spiral groove in the shield, similar to the other. The crosshead is held between two check-nuts, on the coupling-nut. It carries a bar, governing a valve which opens the port when the piston and drill-bar move back, and shuts it when they move forward; the air is always pressing during the backward stroke. The area of the back of the piston being greater than the front, the forward pressure preponderates and carries the piston forward, and when cut off the backward pressure returns the piston. The piston-head of this machine has a diameter of 4~- inches and the diameter of the piston-rod is 4 inches at the large end and 2;} at the small end. There are, therefore, 12.87 square inches of area on the back, upon which the compressed air acts to drive the drill forward against the rock, and 4.23 inches area on the forward end upon which the air acts to throw the drill back out of the hole. As the pressure was not removed froml the front of the piston the motion forward was due to the difference of area between the back and front of the piston, viz: 12.87 - 4.23 = 8.64 square inches. This machine was automatic, and it generally continued to work until some part gave way. No part of it was found to be strong enough to withstand the shocks for any considerable portion of time. The union nut was its weakest point; and the breaking of this nut generally destroyed the part of the piston to which it was attached. The springs of the feed ratchet-band were also almost continually breaking. This machine had 80 pieces; of these 23 were screws, 15 pins, and 7 pieces of cast iron. It weighed 240 pounds, made about 200 strokes per minute, and cost about 8400. Its longest run, without breaking, 36 MECHANICAL APPLIANCES OF MINING. was five days. To run for two days without breaking some part of the machine was considered fortunate. More than one breakage a dtay was the average. The experience with these machines at. the Hoosac tunnel was discouraging. About forty machines were used there, and of tlese eight or ten were originally vertical, and iltended for use in sinking the central shaft. Owing to the many breakages it was difficult to keep up a supply, and the progress of the work dcilminished in proportion to the giving out machines. It was the opinion of the engineer that if a constant, su)ply of machines could have been furnished the progress would have been much greater than that attainable'by hand labor. The average'iif'e" of one of these machines was about eighty hours, and it is said by those familiar with the operations at the tunnel at that time, that soon after starting them at work the tunnel seemed to be a highway, along which a crowd of people was continually passing, each person carrying a portion of a drilling machine, or tools and imaterials for repairs. This unsatisfactory experience led to the gradual abandonment' of the lBrooks, Burleigh, and Gates machine, and the substitution for it of a new and simpler machine, made by Mr. Charles Burleigh. THE U13URLEIGHI- ROCE DRILL. Abandoning the idea of constructing a machine upon the Couch or hollow piston principle, MAr. Burleig'h purchased the Fowle patent2 and. conmmenced the construction of machines with solid pistons, arranoginng the details of construction so that the parts should be few in nulmber, and strong enough to bear the great shocks of working. In this lhe claims to have been successful; and it is stated that sixteen out of the twenty machines furnished for use at the east end of the tunnel were still in operation at the close of the stummer of 1869, some of them having been in use since November, 18G63. According to a report made by a joint committee of the MIassachusetts legislature, the construction of this drilling machline, in 1867, wavts substantially as follows: It has a solid (so-called) cast-steel piston, to one end of which the drill or bit is attached, while the other end within the cylinder, by means of suitable m1echanism, operates the valves. The piston-head has a diamneter of 4.25 ilches; the piston at the 1:r-1ge end 3 inches, and at the small end, 2.75 inches. The number of inches of air area is thus 8.20 when the drill is thrown out upon the rock, and 7.07 when returning. On the back end of the piston is a section of a ball used as a canm, which worlks the valve and the feed motion. The movement of the piston brings the ball into contact with these Carns11S ad,1 by rocking themn back and forth, opens and closes the valve. The cylilnder is supported upon parallel ways or a bed-plate, upoon which it slides up and down as miovedl by the feed-screw. This feed-screNw passes through a gallows frame, attached to the upper end of the ways, and the lower end of the screw, passing through a feed-nut, enters the cylinder. The end of the piston is drilled out, so that the feed-screw is not struck during the oscillations. The feed-nut is secured between two collars, so that it turns easily, and its outer edge is cut into a ratchet, into which works a pawl, operated by the piston, turning the nut upon the fixed feed-screw, and moving the cylinder, drill, &c., forward. This machine weighed 372 pounds, including the ways or bed-piece; without the ways the weight was 212 pounds. It comprised eighty pieces, and had the same number of screws and pins as the Gates, Brooks, and Burleigh machine. Its number of strokes was 300 a minute. They MACHINES FOR DRILLING ROCKS. 37 stood the work much better than the former nm2a1chines, and their average'li-fell in the tunnel without repairs was about fivee dals. Onle worked for fourteen days without repairs. The external appearance of the Burleigh drilling-machine as now mlaude is shownI by the figure. it is simpler and stronger than the imachi3ne of 1866. It has 27 pieces less than that maclhine. Five sizes are mnade, drilling from i - inch to 5k —inch holes, and feeding' from thirty inches to eighty-four inelhes without change of drill-points. Thepistonbar, to which the drillpoint is directly attached, is made of solid cast-steel. The machiaine is so constructed tliat the piston-bar is the onily' part of the inachine which receives the shock resulting fromz the blow uponl the rock. WYith a / pressiure of 50 pounds to the square inch, the drill strikes f rom 250 to 300f 2 blows per minute. It _ w(eighs from 150 to 1 000 __pounds, accordino to __ gm size, and can be operated _:e_ either by steam or by i_-'_ complressed air. The size i recommended for ge,,n-. erali mining is the tunnel-size, weighing aront Burleigh Durlling-ma chine 400 pounds, drilling 1 to 21-ilnchl holes, and feeding 36 inches without chang ye of drill-points. It will drill firom 2 to 6 inches a minute accoiding to the hardness of the rock. Besides being in operation at the Hoosac Tunnel, these machines are or have been in successfnl wrorking operation in New Yorl, Chlicago, J,ersey City, Hell Gate, Scranton, Lake Superior, Color ado, Tova Scotia, Union Pacific railroad, Bostoni and Hartford railroad, &c., and in deepening the beds of the Illinois and Michigan Canals at the Des Moines Ilapids. In Colorado, Mr. Burleigh is running a tunnel to intersect several lodes at a considerable depth. It is found advantageous to mnake this tunnellarger than is usual, in order to have room for the machines,and two tracks. It is, therefore, cut eight feet high and nine feet wide. A double track is laid with iron rails as the work advances. Two inside shifts of men, four in each, are worked regularly; and with the drilling machines the progress in a hard crystalline rock has been, of late, as 38 MECHANICAL APPLIANCES OF MINING. great as 60 feet per month. In one week, 15 feet of advance was made, and at a cost per foot of' 837 50, including all expenses. The tunnel has now penetrated 415 feet in the solid rock, and the average rate of progress for solne months before the machines were carried to their present degree of perfection was 40 feet per month, which was at least four timnes as great as could be accomplished by hand labor. The expenses of running a tunnel in Colorado, near Georgetown, are much greater than at the East. Miners' wages are $4 per day; blacksmlliths', $6; powder, $8 per keg,; wood from $5 to $6 per cord, and all supplies are costly. The cost of driving the tunnel up to March, 1870, had been $62 per running foot; which is much less than it would have cost by hand labor alone. The Baltimore Tunnel, in the vicinity, is being driven with three shifts, of three imen in each, at a rate of 50 feet per month. Another tunnel, worked by hand labor alone, is advancing only 8 feet per month. lr. Burleigh thinks that he can drive the large sized tunnel more rapidly and cheaply than one of thle ordinary dimenlsions. At Hallett's Point, near New York, these drills have been advantageously used; and it is believed that they accomplish from three to four times as much as can be done by hand for the same cost, and in lmuch less time. At the Hoosac Tunnel, (Jaluary, 1.870,) the Bnurleigh drills are used in driving the "b headings " only at both ends of the tunnel-nille machines at the eastern end and eight at the western end. The heading or advanced opening is 8 feet high a nd 24 feet in width; and in the easternl end is nmalde on the floor, and in the western end, next the roof. The enlargeiment is at present carried forward entirely by manual labor; but arrangements are making for the use of the muacine drills for the enlargemnent of the eastern end. The rock is a compact mica slate, in which, at the western end, veins of quartz, sometimes mnany feet in thickness, are of frequent occurrence. In the eastern end, hownever, the mica slate is comparatively free froml these veins or bands, and the rate of progress there is munnch greater. In the western end eight drills are kept constantly at work. Four drills are mnonted upon a carriage, whicll with its load of drills, tools, &c.x weighs, by estimate, about five tons. There are two carriaoges, xwhich are brought into position upon parallel railvways, laid as the wvork progresses. The holes are commenced withl 2-inch drills, and finishled itth 1 —inlch drills, or drills which cut holes of those diameters. The average depth of the holes is about 50 inlches. At thel western end, where the quartz veins are so frequenit and harcd the working of the drills is so constantly interruptled by stoppages that it would require very extended observation of one machine to determine the work it is capable of performing. Oine of-the m achines, in the presence of 1Xmy brother, drilled about twelve inches iin ten minutes, almakig, as nearly as lie could estimate, sometlhing over 200 strokes per minute. The rock consisted largely of quartLz. In boring a hole 5 feet in depth in such rock, the drills are ofteen changed as many as tenl tiles. Accordinlg to Mr. toscoe, Imanager of the western end of the tunnel, onle of thle new drills had drilled a hole 5 feet in depth in quartz rock, such as frequently ocenurs there, in 25 minutes. At the easternL end, where the rock is mlica slate without thle heavy quartz veins, a hole of equal depth is of'ten drilled in friom 10 to 12 minuites. According to Mr. Shatley, froml 800 to 900 inches are drilled in the western headingg dluring every shift of eight hours; and the daily progress of the tunnel is aboutt 4 feet. In the eastern end, however, with nine drills, from 1,600 to 1,800 MACHINES FOR DRILLING ROCKS. 39 inches are drilled every shift, and the daily rate of progress is about 6 feet. Blasting is done twice in every shift. It is the opinion of the superintendent that in the eastern end the cost of drilling by the Burleigh drill is to the cost of drilling by hand, as 41 to 7. In the western end, however. it is believed that the machine drilling, owing to the numnerous stoppages, is as expensive as it would be by hand. Each drill requires the constant attendance of two men. In hard rock it is foundc necessary to feed the drill by hand instead of employing the automatic arrangement provided for that purpose. Hence, at the western end, where the rock is so highly quartzose, the feeding is done entirely by hand; but in the eastern end, where the rock is less hard and of more uniforml character, the feed is automatic. At both ends the wear alnd tear on the machine drills is necessarily great; bnt in the western end particularly so-so great, in fact, that on an average two drills are in the shop for repa.irs to one at work in the "heading.' But this end had not beemn fully supplied with the new Burleigh drills. As before stated, these drills mnay be operated by either compressed air or by steam. For all underground operations the former is used. At the western end of the Hloosac Tunnel four of Burleigh's air-coinpressers are used for the compression of air to work the drills. The compression is rapidly effected 1y pumps, worked by a steam engine. 7;, The reservoir at that place consists of two cylindrical vessels of boiler iron, 25 feet long and 5 feet in diameter~ in which i the compression is carried to fiom 50 to 60 pounds to the. _____ inch, or three and one-third to four atmospheres. The air is conveyed in iron pipes 8 inches in in.terior diameter., COMPRESSED AIR AS A! "OT"'! IN MINING. The annexed fignre shows the form of the new miachines used by the Burleigh Drill ilI Company for compressing the air by which the drills are worked in the end of a tunnel, 1 or for other purpose's Whi.ere i/i/lI.u~\ 37 -: compressed air can be used to It is obvious that for under-: 1 [..I shafts, and in tunnels, steam... cannot be used as a motor._ Aside from the difficulty of conveying it great distances in pipes without great loss by con- Burleigh Air-compressor. 40 MECHANICAL APPLIANCES OF MINING. densation, its discharge in the confined galleries of a mine would rencler Yworking imlpossible. Coimpressed air, on the other hand, whenl conveyed from the exterior to the interior of a mine, and discharged there, gives a constant supply of fresh, pure air, promoting the health and comfort of the miners. The compressors now used with great success, consist of a steam-engine connecting by means of a crank shaft with two single air plumps, arranged as seen in the figure. It is very compactly and strongly built, and, by a nice adjustment of the cranks, the greatest power of the engine is applied at the point of greatest resistance. These compressors are mnade of three sizes, rated as Nos. 1, 2, and 3, and with the following dimensions: Di3mensions of air compressors. N'umber Oine. Number Two. ~Number Three. Steam cylinder.-.................6. 6+-inch diameter.- 9-inch diamneter.. 10-inch dianmeter. 15-inch strolke. —. - 18-inch stroke 1. -inch stroke. Air cylinders, each —.............. 10-1-inch diameter _12-ilch diameter... 14}-inch diameter. 10-illnch stroke. 15-inc stoke -. 15-inch stroke. Size of base-45.. -...... 45 X 35 inches...- 45 X 56. inches.. 48 X 64+- inches. Extreme height.fee 5......inches- 79 feet 535 incch es.-. 9 feet 31 ilnches. Weihlt -3,800 pounds -... —.. 7,600 pounds.... —-- 11,000 pomlls. Cubic feet of free air com)pressecd per illnute at 90 revolutions.-... 90.19 cubic feet.. —-- 176.70 cublic feet- 266.97 cublic feet. Size of discharge pipe.-... —-------- 2 inches...-.... 21 inches -... —-.- 3 inches. The air, when compressed, is taken into a tank, or air-chamber:, a nd thence carried to any desired point in pipes, in the same malnner that steam is carried. Connection between the permanen t pipes and the rock drills upon the carriages is made by flexible rubber pipe, which is uncoupled Nwhen the carriage is irun back for a bast. The constructors of these compressors claim that, with eighty pounds of steam, they have compressed Gair to an equal degree, so as to protluce an equilibrimn between the condensed air in the receiver and' the steamu in the boiler. un regard to the economy of transmlission of power to a distance by me-eanis of comnpressed air, the practical results at the IHoosac Tunil,,c ae, e extremely favorable, and show, as already mentioned, but a shligtd d-iference of pressure-about two -olonds-betw, een thle two extremes of a pipe 7,150 feet long and eight inches in diameter. The itllowingo tible shows the result of soime experimlents made while from five to 1ilne drills w-ere in olperatioln,esmtlls of experlments supon the loss of presssure by the flow of air in catn 8-inch pipe. Timle.' _ Pou;ds. lPounds. -i'ouLnds. 1.10 p.......... —-------------------------------- 2 90 9'2 9 63 G2 i 1 1.20 P. m............... ----------------—.. —-------------- 2 104 96 7 64 62 2 1.30 I). 1. —--------------------------------- 2 112 104 6 65 62 1 3 1. 50 1). I. ----------------------------------- 2 9t 96 5 66 63; P 1 2 p. Il ----------------- --------------- -- 94 4 67 C)4 3; 2. 10 P. il.................. —-----------—... —---------------... 2 8 92 66 64[ 22. - n,. l. III. —------- -.-..- -..-. — 2 86i 92 6 67 66 i 1 1p.-2 6 980 p8 6 s 6.). I 2. 40 p. ----------------------------------- 2 s 91 5 67 6 I 2. 50. ---------------------------------- 9 90 6 65 64 1 3 p. 1n m- 2 92 0 65 63 Average loss of pressure, 2 poulndls. Average numnber of drills rulling, G. Length of 8-inch,air-pip-e from comipressors to heading, 7,150 feet. MACHINES FOR DRILLING ROCKS. 41 These results are in accord with those obtained by the engineers at Mt. Cenis, where, at the date of the report of progress of the work in the year 1863, the air was conveyed a distance of nearly 2,000 metres, and worked nine drilling machines with a force of two and a half horsepower each. The tube, like that at the Hoosac, was nearly eight inches in diameter. The air was compressed to six atmospheres, and its velocity in the tube was about three feet per second. The transulission under these conditions was not attended by any sensible loss, and the pressure was the same when the drills were all in operation as when they were at rest. A series of experiments were made at Coscia by order of the Italian government in 1857, Upon the resistance of tubes to Ithe flow of air through them, and the following conclusions were deduced: 1. The resistance is directly as the length of the tube. 2. It is directly as the square of the velocity of the flow. 3. It is inversely as the diameter of the tube. The whole subject of the transmission of power by compressed air is most thoroughly and ably discussed by Professor F. A. P. Barnard, in his report upon the Paris Exposition* of 1867, to which reference is made for further details upon this most important subject. The compression of the air at the eastern end of the I1oosac Tunnel is effected by water-power. Four 24-horse turbines operate 16 air-pumps, each of 131j-inch bore and 20-inch stroke; but these are not all used totogether. The use of the machine drill in sinking the central shaft, now down over 800 feet, has been discontinued. Directions for runding the B? rleivq. dr-ills.-Before attempting to start a drill the palrts, should be thoronughly oiled by introdulcinlg oil through -the pltlg markecd oil," and also behind the "feed lever," beneath the-" lonmentum1n piece," be)tweell rotating ratchet and friction ring, and between rotating ratchet and inside sleeve. In setting the drill carriage preparatory to drilling, the rear part of the same should be raised three to four inches above a level by turning down the back jack-screws. The machine is now ready to receive the drill point. This is done as follows: Raise the piston sufficiently to admit of the drill point entering the chuck. In doing this be carefnl to observe that the c" momentum piece" is knocked back so as to clear the ball on the end of piston which moves the " lmolmentum piece" and valve. Now let tile piston drop dowin on the drill point and firmly secure the same by tightening the bolts in the chuck. Now feed clown the cylinder by the cryank on feed-screw, until the drill point touches the rock, and then feed it down three-quarters of an inch more if a " Tunnel pattern," or one inch if a "New York pattern," so that the piston will not strike the lower cylinder head when the drill is at work. The drill is no-w ready for Twork. Let on steam, and if it does not at once start, knock the " momelntum piece" (with a mallet or stick of wood at the knob upon the same) forward and back. If the piston raises and strikes one blow and stops, the valve gland must be tightened a little to prevent the valve from falling back over the port and cutting off the steam. Nov strike the "' Imomentunm piece" as before, and the drill will start, unless the valve gland has been tightened so much as to prevent the full throw of the valve. (Experience will guide il this matter.) Again, if the cylinder is fed down imore than three-quarters of an inch, as above dlescribed, it will not start, in which case turn back -the feed-screw a little. Having once started, if the drill rotates more than one tooth at a time, the lower "C stuffer" should be screwed up sufficiently to increase the friction on the piston rod to reduce the rotation. In case the drill -will not rotate, screw up the set-screw in the friction padl, which will cause rotation. Observe that the spring over the rotating pawl is of sufficient strength to cause the pawl to throw into the notch, as the drill rotates. The same care should be used with the spring over " qualifier," for if too weak, or fromI any cause broken, the drill will feed itself down, cutting off tlhe stroke, and in consequence stop. By carefully following the above directions, the successful working of the drill is secured. Great care should be taken to prevent the piston from striking the lower cylinder head. This occurs if for any cause it does not feed fast enough, which -will be X Malchinery and Processes of the Industrial Arts, &c., pp. 137-150. 42 ~MECHANICAL APPLIANCES OF MINING. the case if the spring over feed lever is not of sufficient strength, or a soft place in the rock is reached, or if the drill strikes through into a seam or cavity. This will be immediately detected by the difference ill sound of the blows, and when it occurs [the steaml should be at once shut off, or the drill rapidly fed down by the crank on end of feedscrew. To change drill points.-Ha-ving drilled the length of the first drill point, if a greater depth is desiredl, the drill, points will be changed by following these directions: Loosen the bolts in the chuck, allowing the drill point to dirop out. Bring the fralme or carriage to a level by turning the back jack-screws, which will allow the passage of the longer drill down past the cylinder; raise the piston as before described, until the drill enters the chuck —then raise the rear of carriage to its former position-secure the drill and proceed as before. Shawpelinzg thle drill paoints.-In sharpening the drills, care should be taken. to form the points in the shape of a letter X, and not square like a +-. On the two-inch (tunnuel or:miining bit) there should be a differenlce of at least ~ inch between the lips of same. On the three-inch or New York pattern there should be } inch. If these directions are not followed the hole will be five-sided and cause the drill to bind. In drilling, water should be occasionally fed into the hole to keep the point cool and wash out the debris. In case the drill binds from running off or any cause, the bolts in the clamp which holds the drill should be loosened to relieve the same. The above directions for runining a drill aplply more particularly to vertical drillilng, but are generally applicable to various kinds of drilling. To take the 7machise apcrt. —Take out the bolts in the lower cylinder head; all the setscre ws on the side of cylinder, feed-lever, momentume piece, rotating pawl, and friction pad; then pull11 the piston down with a jerk and it will start the inside sleeve. lBy continuinig this operation the inside works can be removed. In putllting the drill together, wvhen the inside works are put in observe that the upper end of inside sleeve is flush with the lower end of rotating pawl, and that the -back ring is opposite to the back set-screw. Turn the set-screws down firmly and replace the other parts as befiore. SO-M:IMEILLER'S ROCEK-BgRILLIN'G MACHINES. The following notice of rock-drilli-ng by machinery at Nl ont Cenis is comzpiled front the report by Messrs. Geyler and dlAligny. It is gen1erally known that these i machines are worked by co mpressed air: On the Italian side of the Alps, at Bardonneche, (the Piedmont ent-rance,) the air compressors are a kind of hydraulic ram, the valves of which are arranged in such a way that, at each lift of the valve admlitting water, a certain quantity of air, at a pressure of five atmospheres, is forced into a reservoir 10 mletres long and 17 cubic metres capacity. The air compressors at iModane (north side) are comaposed of a horizontal cylinder full of water, in which a piston works, and of two vertical cylinders receiving the air, and provided with vatlves in their unlper part. 13y the motion of the piston a quantity of air, equal to that of water displaced by the movement, is introduced and expelled at each stroke. The air is conducted to the boring ma'llchine by cast-iron pipes of m1.20. It has beenl ascertained that the loss due to friction is about one-tenth of an atmiosphere. The boring machines of M1Ar. Sommeiller are essentially composed of:a cylinder in which the compressed air works. The piston rod traverses the heads of this cylinder, and carries on one side a screw which coulmmands the distributer. A machine similar to a steam-engine commlands -the slide valve of this distribLter. This arrangement w-as adopted inasmu1ch as the strokd of the piston woich carries the drill varies with the hardness of thle rock and the position of the drill in the hole, and no reliance could be placed upon the introduction of the compressed air by means of the percussion alone. The whole apparatus weighs 200 kilogranmmles. It rests upon a firame open in the center; the sides are 0111.03 wide by 0111.05 hitg)h, and 011.09 apart; their length is 21n.70. They are cut upon their inside faces with MACHINES FOR DRILLING ROCKS. 43 a screw thread, in which a screw moves, and the edge of their lower faces is cut with rack teeth, in which a pawl works. The cylinder of the distributing machine is 0111.06 in diameter. The stroke of the piston is 0m.10. It is furnished with a connecting rod and a crank, an(d by means of gearing gives a, rotary movement to a square steln, upon which is fixed, first, a pawl, which advances tooth by tooth a ratchelt wheel provided with sixteen teeth, and fixed invariably on the prolongation of the piston rod in such manner that, after sixteen blows of the drill, the ratchet, the piston, and the drill have made a comrplete revolution; second, a plate furnished with a cam which moves the slide rotd, and if we suppose that the slide valve, pushed by this cam, advances and stops the aperture for admission, the air which acts escapes througah the opening which communicates with the atmosphere by the hollow passage in the slide valve, and the piston is carried to its origincal position by the constant pressure which is exerted on its front face. At tlis instance the valve, abanudoned by the cam, is pushed back suddenly to its initial position, by the'difference of pressure which is exerted upon1 the two faces, and thus opens the inlet port. The diameter of the piston of the boring machine is 01m.06; its stroke, 0111.20; and it gives 200 blows per minute. This nmachine is single-acting. The compressed air enters by the opening in constant comnlmunication by the conduit with the front part of the cylinder; when the piston is at the end of. the stroke, the slide opens the inlet port, and the piston only advances in consequence of the difference of the pressure of air on its back face fitted with a slender rod, and on its internal face, of which the area is reduced by the large shaft of the tool-carrier. The impulsive force upon the piston is, for some of these machines, 95 kilogramnmes, and for others, 150 kilogratmmes. We have before explained how the drill is made to rotate. It remains to show how it is made to advance, and how it can be rapidly takeen out in case of need. If the screw, constantly geared into its nut formed by the internal filleted faces of the beds, were fixed permanently upons the shaft, it would follow that in each rotation of the drill it would advance the cylinder by a length equal to the pitch of the thread; but it should, on the contrary, only advance at the same speed that the drill enters the rock; therefore the screw works loosely upon the shaft, and only turns when a clutch box catches it, this clutch being continually pushed by the action of a spiral spring, which is retuined by a rod connected with the clutch, and carrying at its front extremity1. A fork, the teeth of which rest against those of the rack on the lower part of the bed plate. 2. A prolongation terminated by a semicircular appendage. If we now suppose that the piston is reaching the end of its stroke, with the drill scarcely touching the bottom of the hole, a tappet fixecd upon the shaft of the tool-carrier strikes the above-mentioned appendage, forces it to drop, and detaches the tooth from the rack. Then the clutch box, impelled by the spring, catches and turns the screw, and the striking cylinder advances till the fork is caught by the following tooth of the rack, and thus disengages the clutch. It may be conceded that Mr. Somumeiller has constructed an ingenious machine which fulfills the following conditions: 1. It strikes hard and rapid blows upon the rock. 2. It transmits a self-acting rotary imotion to the drill, required to prevent it from becoming fixed in the hole. 3. It imparts also a progressive, self-acting, and regular advance to the drill as the hole deepens in working. 44: MECHANICAL APPLIANCES OF MINING. 4. And lastly, it can be rapidly drawn back to change the tools. The tool is a drill, with the cutting-edge ill the form of a Z. It makes a hole of 0.09 and 0111.04 in diameter; but in the first case it is furnished for 0n.20 behind its head, with a bulge which tri-ms or reamis the holes to full size. The stroke of the machine is but 0m.)80, but it can nmake a hole to a depth of 0m11.90, by reason of the length of the drills, which vary from Om.50 to 2m. The apparatus placed before the breast of the gallery to be attacked carries 8 drills, which cover a section 4 metres wide by 3 metres high, equal to an area of 12 square mietres. Eighty holes are bored, 6 of 0111.09 and 74 of 0111.04 diameter, and 011.90 deep. The daily work has varied evidently according to the hardness of the rock. In March, 1863, it was 1111.10 ill twenty-four hours; in April, 111.40, and in some parts of the strata even 2r11.50; but when the bank of quartz was met, which was 3308 metres thick, the advance was hardly Om.50 per day. During the month of:March, 1863, it was shown that each explosion of 0U1.70 to 01.80 required six hours for boring the holes, and four hours for the miners carrying away the rubbish. Th1e staff employ ed for the boring of the holes during twenty-four hours was as follows: TwO shifts ------------ - 16 fwo shifs.................................................... 16 M iners -- - - - - - - - - - - - - - - - - - - - - - - - - - 2 Laborers for taking away the debris.....-...-.................... 8 Superintendents..-... o... —-..o....... --—.... — 2 Total -...2.... -.-..-......-............................ 8 The compressors required.........- -.................. 9 Totall-. -........-.................................. -- 37 In 1863 for 8 machines workinl, there were 60 in the shop. In1 1867 when the work was carried oin both from the French Cand Italian sidles the nnmber of machines worlking was 16, and of those in the shop for rep)airs 200. Int 1863, for repairing 8 perforators working in a coarse sandstonle, (/-res grotos gra-i0s,) the staff attached to the workshops consisted of 24 mlen. InI 1867 the number wafs mPuch greater, but exact information Could not be obtained. The work had, ihowever, been offered to a company ant 6,000 francs per running metre, the company takinga all the apparatus an4d agreeing to repair the tools and clear away the debris. This was refused, although the price was equal to 500 fralncs per cubic metre. The enormous shocks which the machine was subjected to obliged them to change the iron beds for Krupp steel ones; the springs often broke, and the (Crills did not advance 011L.20 or 0m.30 without requiring repairs. DIORING'S DRILLING MACHINE. Mr. DMring, of iRuhrort, in Westphalia, has constructed a drilling machlline that has been used to great advantage in the zinc llines of the Vieille MAontagne Comlpanly at MoIresinet near Aix-la-Ch1,apelle. The director of these mines stated in 1867 that 11 of these machines, two of theml of a recent construction, had been in actual use there, a nd thlat in one of the levels, where the rock was a very hard qlartzose dolonmlite, they had made an advance, of 3 Inetres in 14 days, where by h11and drivig 1~ mnetres only could be achieved. 8omnetimes the machine could advauce MACHINES FOR DRILLING ROCKS. 45 4 metres in that time, and with only 2 ml-en instead of 6. A six horsepower engine is required to work 2 machines; the air is compressed to 1U atilospheres. For one working machine it requires 2 in reserve. The speed per muinute is 01.03, including replacing the drills. Each drill will not bore mlore than 0Om.20 to 0m.30 without being replaced. Its speed of advance at Vieille -Miontagne over ordinary borers may be considered to have been treble in hard rock, but only double in soft rock. This apparatus of DTring weighs 45 kilogrammnncs, and constitutes the borer, properly so called. It is erected upon a special carriage, which allows any direetion to be given to the drill that is desired. The pressure of the air varies from 3- of an atmosphere to 1~. This machiine is composed of a cylinder Om.400 in diameter, and 011m.300 long. In this cylinder a piston moves, to which is fixed the stemi of the drill. The compressed air is distributed by means of a slide valve, and, after acting freely, escapes into the air. Two ratchet wheels, fuirnished with dogs, are placed at the back of the cylinder, and are plut in action by the prolonged rod of the piston by means of a fork which comemands the dogs. One of the ratchet wheels serves to give to the drill a rotary movement on its axis; the other ratchet, which is nearest to the cylinder, by means of a toothed wheel advances the tool upon the support. The arrangement is such that the drill advances only when the piston has run its stroke. A jet of water is Constantly thrown into the hole for the removal of the dclebris. The drill most used is pointed in the form of the letter Z; aund it is found that when worked in the machine it does not blunt as rapidly as when worked by hanid. Mr. IDoring has put his machines into operation in a very deep minethe Tincroft, in Cornwall-where the rock is the hardest in that country, and one is to be introduced at the Dolcoath mine. It is represented as miaking good headwa.y in the hard rock of the Tincroft. BERGSTROMl'IS DRILLING MACHINE. Bergstrom's drilling machine originated in Sweden, and has been in use there at the Persberg imine. A machine exhibited at Paris in 1867 was said to have worked for 700 days under ground, and to have bored in the aggregate 1,000 metres. Upon hard granite, ia trianls with the drill, it bored 2 metres in 1 hour. The drill is impelled by compressed. air, in a cylinder similar to that of Doiring's machine, but without an automatic advance movement. It gives frono 300 to 400 blows per miinute, and the diameter of the drills varies from 0111.018 to 0nm.025. The weight of the whole apparatus is only 120 pounds, and it is supported upon a steel bar, which must be fixed in a direction parallel to that of the intended bore-hole. The cylinder is made to travel along tUhis bar. It may here be mentioned that in 1856 Karl Schumann, of Freiberg, Saxony, constructed a, boring machine, to which those above described and the drill of General Haupt are similar in some respects. HAUPT'S DRILL. This percussion borer differs essentially in its construction from those described. It works by means of steam. The drill passes down a hollow piston rod, to which it is fixed by the extremity which is before the workman. The reciprocating movement is communicated directly to the drill, and by a special arrangement of the slide valve the introduction of the steam into the cylinder is avoided until the piston has arrived at the end of its forward stroke. 46 MECHANICAL APPLIANCES OF MINING. The force of the blow of the drill upon the rock depends on the pressutre of the steam upon the piston. It will be observed, besides, that the useful effect of the drill depends much more upon the section of the piston and the pressure of the steam, than on the length of the stroke of the piston, and that the consumption is proportioned to this last dimension. The length of the stroke of the piston is Ol.102, and the number of blows per minute is 375. The movement of rotation is given to the drill in the following way: The box in which the shaft of the drill is held, and which turns with it, carries a ratchet wheel on one part of its circumference, an d around this wheel is a ring furnished with a pawi, which catches in the teeth of the ratchet wheel. This ring also carries a projecting tappet, whllich passes in an inclined groove left in the outer envelope of sheet iron which surrounds the steam cylinder. The tappet participates in the movement of the piston and drill, and by sliding in the inclined groove turns a screw with which it is combined, arid by means of the pawl gives the ratchet wheel and the drill a rotary motion. This arrangement woulcd be insufficient alone, since the tappet imoving in both directions in the groove destroys, to a certain extent, during the forward stroke, the useful effect produced during the back stroke. To obviate this imperfection, and to maintain the rotation transmitted to the drill, there is a second ratchet wheel placed at the" front end of the box that carries the drill., A steel spindle placed in a recess formed by the cylinder jacket locks into the teeth of this second ratchet wheel, so that the movement of rotation only takes place one way. The first ratchet wheel allows the transmission of the rotating movement to the tool; the second forces this movement) to be always effected one way. Mr. Haupt has contrived a special arrangement which causes the drill to always strike upon the rock with the same force, an(d to vary its advance according to the hardness of the rock. If the drill is put into the drill-carrier in such manner that at any given time the mlotion of this latter can be suddlenly arrested while the tool itself continues to moveW it is clear that each stoppage of the tool-carrier will be followed by an advance of the tool; but as this stoppage would diminish the force of the blow upon the bottom of the hole, it is only allowed to talke place at intervals. TIr. Haupt estimates that three horse-power is required for each borer, and that the rate of progress in rocks of ordinary hardness is Om.05 per minute. BEAUMONT AND LOCOCK'S DRILLING ENGINE. This machine is worked by compressed air; its object is to pierce a gallery of two metres diameter entirely by the machine, aided by powder for disengaging the core of rock which is left in the middle of the anutlar trench cut by the drills. This machine is composed of a cast-iron plate which carries on its circumference thirty-six drills made of cast steel, and in its center a similar drill. The diameter of the plate is about two metres, and is the same as that of the gallery to be driven. It is fixed on a hollow iron shaft, about two-thirds of its length being a piston, which imoves in a cylinder. The stroke of the piston is about 0m.30. A slide valve introduces the air (compressed to two atmospheres) to each ftce of the piston, and gives it an alternate movement of 250O blows per minute. A worm, worked by a special mechanism, turns the axle with the drills by means MACHINES FOR DRILLING ROCKS. 47 of a screw wheel combined with the axle. The carriage on rTwhich the piston shaft is mounted receives a forward motion by a specialf arrangelnent. The water which is thrown into the groove formed by the drills enters the interior of the shaft, and by pipes branched upon this axle is conducted to the circumference of the plate. This is evidently one of those machines that cannLot long withstandc the extreme violence of the impact essential to rapid drilling. If it is almost impossible to construct a -machine with one drill that will work long enoughl without repairs to make it an economical success compared with hand labor, how much can we expect fron an engine armed with thirty-seven drills, all rigidly attached to one piston? FORD'S DRILLIN G MACHINE. A power-drilling machine has been constructed atnd put into operation in one of the mines at Sandhurst, Australia, and is said to effect a very considerable saving over the ordinary process of drilling by hand. Mr. Joseph Millin, the manager of the Hustler's Reef Company, states that drilling in ground that would cost forty shillings per foot with, hand labor can be wrought with the machine for thirty shillings; or, if with hand labor at sixty or eighty shillings, with the machine for forty shillings. The harder the ground the greater the saving. The machine appears, from the description given, to be similar in construction to the Burleigh drill. The constructor,,Mr. R1. G. Ford, of Sandhurst, describes the drill as follows: In Ford's rock-boring machine the motion of the roek-boring tool is reciprocating, and the motive power is compressed air or steam, at a pressure of sixty pounds per square inch, acting on a piston in a cylinder. It presses constantly on a small annular space in front of the piston, and intermittingly on the whole area of the back of thepiston; a percussive action is thus given by the borer carried by the piston rod. The ports for the alternate admission of the compressed air behind the piston, and for the exhaust, are opened and closed by a valve worked by a small piston, thus securing the.full pressure on the back of the piston, and giving a free blow and a clear exhaust for the return stroke. The air-ports and the mlovement of the valve are so arranged that the piston cannot strike the front and back of the cylinder. The rotation of the boring tool is self-acting7 and is caused by the piston rod working a ratchet and click round a cylinder attached to the front of the working cylinder, and as the piston reciprocates it carries itself round the cylinder and makes a complete revolution every twenty-one blows, by which means the machine bores a perfectly round hole, and the drill cannot move more or less. than a twenty-first part of a revolution at each stroke. The feed is self-advancing and self-adjustable and variable, feeding with precision as fast as the tool has power to penetrate the rock, but no faster, varying its feed in the same hole with the varying hardness of the rock or sharpness of the tool. This is effected by the working cylinder being provided with an exterior cylinder in which it can slide, and the compressed air is constantly tending to propel the worlking cylinder forward, but is retained by a screw, which is prevented from turning by a pawl, which the piston strikes when it makes a full stroke, thus releasing the screw and permitting the working cylinder to advance forward as the hole increases in depth. An ordinary drill is used; the only alteration required is the head, which is made to fit the mnachine. The drills can be made to bore holes from three-quarters of an inch to two inches in diameter. The weight of the blow struck by the machine can be varied from 1 pound to 510 pounds, and the number of blows from 20 to 600 per minute, by the attendant simply moving the handle of a small air-cock. The air-compressor used at this mine with Ford's machine is very simple, consisting of a cylinder nine inches in diameter, bent like the letter U, with a piston working in one leg only, tihe other being filled with water. The piston has a stroke of two feet, and as it moves up and down in one leg the water rises and falls in the other, thus making it double-acting. The piston works through a stuffing-box atthe bottom, and the inlet and outlet valves are placed at the top. A small supply 48 MECHANICAL APPLIANCES OF MINING. of water is admitted at the inlet valve with each stroke, and is thrown into the receiver at each return stroke, thus circulating through the apparatus, and carrying off. the heat given out by the air when comnpressed. An old boiler is used as the receiver, and the compressed air is conveyed to the drilling lmachine in iron gas-piping. LESCHIIOTS ANNULAtR DIAMIOND DRILL. (fl ii~ll~!ii EiN Diamond Drill for testing or prospecting. The drills about to be described work upon an entirely different principle from those noticed in the preceding pages. The latter are all of the MACHINES FOR DRILLING ROCKS. 49 class of percussion drills, and cut by the force of the blow concentrated at the point of the drill. The diamond drill, on the contrary, is not used percussively7 but by virtue of its extreme hardness it is made to cut away the rock by contact and pressure. The drill is pressed firmly, and is rapidly rotated against the rock to be bored. The application of rough black diamonds to boring and cutting into rocks was made in 1860, by Mr. Rodolphe Leschot, a civil engineer residing in Paris, and formerly a student in the Rcole Centrale. He found by experimenting that such diamond(s, firmly set in the end of an iron or Steel tube or cylinder, could be made to bore holes in rock to great depths and with a rapidity before unknown. A short section of a cylinder of soft steel is used for the purpose. It varies from one to three or more inches in diameter, according to the size of the hole to be drilled, and is only about one-quarter of an inch thick. Cavities are drilled in the end of the cylinder, and into these cavities black diamonds of the commlon or bort variety are firmly set, by hammering up the soft metal around them. They are allowed to project about half a millimetre in frollt alnd slightly beyolnd the outer and inner surface of the cylinder or ring. This ring is secured by means of a bayonet joint or screw thread upon the end of a long hollow rod or drill bar, to which a rapid rotation is given. By pressing or feeding this revolving diamond-mounted ring against the rock to be cut, and at the same time supplying it freely with cold water, the rock, whether of soft or hard materials, of clay, slate, or of flint, is rapidly worn away, and an annular cutting' results, leavinlg a central core of rock, which lpasses into the center of the drill and drill holder, and may be broken out when the drill is withdrawn, thus leaving a truly cylindrical hole with smootth sides. The rapidity with which this apparently delicate ring cuts its way into the hardest syenite, quartz, or granite is surprising. The first experinents showed that two men with a machine like an ordinary ifeed drill could bore 0'11.025 in depth per hour. The cylindrical core left in the center was OUn.031 in dianeter and the annular groove 0m.043 in diameter; consequently the p)art cut out was equal to a cylinder 0.n.012 thick. But this method of feeding or advan1lcing the drill was clearly very defective, no allowance being imade for the varying hardness of the rock. Since tlhat tiue very great improvemlents in the way of mounlting, operating, and feeding the drills have been made. The wood-cut represents the drill and its mounting, as manufac-tred by Messrs. Severance & Holt, the assignees of the patent for the United States. This formL is known as the " testing or prospecting drill," and it is designed chiefly for testing the character and value of mineral deposits, although it is adapted to a variety of other work, such as drilling holes in quarries for blasting, and for well-boring. It consists of a small, upright boiler, to one side of iwhich is firmly bolted the casiiron frame which supports the engine andcl swivel, drill-head, gears, and screw shaft, as shown in the engraving. The engine —an oscillator of froln five to sevell horse pow eris shown`at A. B is the screw sliaft with drill passing through it. This sh`ft is nmade of hydraulic pipe from five to seven feet in len(lth, with ar coarse -thread cut on thle outside. This thread, a portion of which is shown in the cut, runs the entire lengtth of the shaft, -which`also carries a spline by which it is feathered to its upper sleeve-gear. This gear is double, and connects by its lower teeth -with the beveled driving-gear, and by its unpper teeth -with the release-gear (E.) This release-gear is fe athered to the feed shaft, (F,)at the bottom of which is a frictional gear fitting the lower gear on the scre-w shaft, which has one or more teeth less than the frictional gear, wllherebl-y'a differential feed is produced. This frictional gear is attached to bottom of feed shalft (F) by a friction nut, thus prodncing a combined differential and fiictional feel whlich rendcers the drill perfectly sensitive to the character of the rock th-oughi which it is 4 M ,50 MECHANICAL APPLIANCES OF MINING. passing, and maintains a uniform pressure upon the same. The severe and suddenr strain upon the cutting points incidental to drilling through soft into hard rockl with at positive feed is thus avoided. The drill proper (passing through the screw shaft B) consists of a tubular bar, made of lap-weld pipe, with a steel bit or borilng-head (D) screwed on to one end. This bit is a steel thimble about foui inches in length having three rows of black diamonds in their natural rough state firnmly imbedled therein, so that the edges of those in one row project forward from its face, while the edges of those ill the other two rows project fromI the outer and imler peripheries respectively. The diamonds of the first-mlentioned row cut the path of the drill in its forriward progress, while those upon the outer and inner periphery of the tool enlarge the cavity around the same, and actdmlllit the free ilngress and egress of the water as hereafter described. As the drill passes into the rock, cutting an annular channel, that portion of stone en-6 circled by this channel is of course undisturbed, and passes up into the drill in the form of a solid cylinder. This core is drawn out with the ldrill in sections sometimes of froil 8 to 10 feet in length. Thle sides of the hollow bit are one-fourth of an inch thick, and the diamonds of the inner row project about one-eighth of anl inch, so that the core or cylinder produced by a tw-o-inch drill (the ordinary size for testing) is one and a quarter inches ill diameter. Inside the bit (D) is placed a self-adjusting wedge which allows the core to pass up illto the drill without hinderance, but which impinges upon and holds it fast when the action of the drill is reversed —thus breaking it off at the bottoim and brinoino it to the surface when the drill is -withdrawn. In order to withdraw thle drill it is only necessary to throw out the release-gear (E) by sliding it up to the feed shaft, (F,) to which it is feathered, when tle drill runs up wnith tile saLie lmotion of the enginle whichl carried it doTwn, but with a velocity sixty times greater; that is, the speed withr which the drill leaves the rock, bringinfg the core with it, is to the speed -with which it penetrates it as sixty to one-the revolving velocity in both cases being the samle. The drill rod may be extended to ally desirable length by simply adding fresh pieces of pipe. Common gas-plipe, or, better, lap-welded iron tube, is found to serve adnlirably for this purpose, the successive lengths being quickly coupled together by -air inside coupling four inches long, with a hole through the center of each to adllit tire iwater. The drill is held firmly in its place by tile ch-uck (G) at thie bottomll of the screw shaft. The small steami pumnp (C C) is connected by rubber hose -with any convenient stream or reservoir of water, and also with the outer end of the drill pipe by a similar hose having a srwivel-joint, as shown in the picture. Through this hose a steady streaml of water is forced by the pumlp into the drill from which it escapes between the diamilond teeth at tile bottom of the bit, (D,) and passes rapidly out of thie hole at the surface of the rock, carrying away all the grit and borings produced by the drill. Where iw ater is scarce or difficult of access, a spout is laid from the mnouth of the hole to the tank or reservoir and a strainer attached to the connecting hose, so that thie same water mIay be used over and over again with but little loss. This pulnp also supplies the boiler. The same parties manufacture another style of prospectinlg drill, simrilar in its construction to that just described, but larger and ml ore powerful. It has a horizontal tubular boiler 3~ by 7 feet, with flunes three inches in diameter, and steatmn capacity equal to twelve horsepower. The engines are two oscillators of 4`-inch cylinder, five-inch stroke, and both attached to tle same crank shaft. The whole is molunted upon wheels so as to be portable. It is geared to runl with twice the speed of the first-described nmachine. Its construction and general appearance, is shown by the cut. The pump P and water hose H fill the same offices as those in the upright machine. This pattern is mounted on large wheels with broad felloes for easy transportation in rough mining districts, and, like No. 1, is all complete in itself. It is especially adapted to well boring, draining, and prospecting, and will bore holes fromn two (2) to five (5) inches ini diameter, as desired, and to any required depth. The total weight is about 3,800 pounds. An open cut or quarry drill is also made. It is similar in its constrection to the last-described machine without the boiler, and has two oscillating engines, B B, of five horse-power each, and is geared three to one. This machine gives to its drill rod 900 to 1,000 revolutions per minte,l and drills in ordinary rock at the rate of fifteen to twenty MACHINES FOR DRILLING ROCKS. 51 feet per hour. It is adapted to either compressed air or steam. A powerfil plunger pump is representecl at A. Severaliace &. Holt's3 Portabule Prospe~.ti'C,; Drill. ~he speedl of boring1t of coulrse depLendls uplion thle charact~etr of' th0 r~ock, ranlging from:t fie feet per hlour i1 verey hard rock to fifteen feet per hlorn iLL limnestone, sand1 rock, ande shale. rThe rate of speed inl drilling' app~ears to be limited 0n~ly by thle -velocityT with w-hichl i~ is p~ossible to r otalte theX clril l. it is claimlned th1a t w^ith onle tho cusan rl l1evo1lution1s perl m~inult e the haridest rock muay be clrilled irom ei2,lt, to ten feet per houvr, the diamlond~s cuttinlg only- the one-four-hun~dred~th part of an1 inich at eachI reTolut~ion~ ~u-~d thle drill thlus adv ancinlg one inchl for evrery tbulr hunldredl revolutionls. This is the, finest or slowvest " iXedl," and~ is ulsed only in flinlt or rock-s ofc greqatest hardnlless; ~while inl ordinlary rock the dri~ll is fedl ait the rate of thrlee h1undfred rev~olutions to the incGh —the dliamllonds~ of courlse, cutt~ing the onle-three-hunldredthl part of anl inch1 at each revolution; andc in mlarble~ sa~nsldtole~ &e.~ at the r)ate o~' >an inchl fbr evrey twvo hundr~ed rSevolultionls. The pressure of the bit or dlrill hecad algainlst the rock; dogs Ilot dlependl upon the lenlgthl andc w~eighlt of thle drlill rodlv andc is no grwea~ter (at the3 depth of,% hulndredl feet thlan w-hen enterinlg the rock at. thle surifhce. The v~ariationls in thle i~ed are effected by simlylul changing one gearwhleel, requliring les~s tha. n five m~inultes' timle. Th-e saime mlachline will bxose holes fromt onle to four inches inl diamxeter, a!s desiredl. Th]e dliamondl teethl axe the only parts of thae tool whlich comte in con — tact with the rock, andi thleir) hardness is suchl thatt mtore thlan tw~ao thou — sanld feet hlave beenl drilledl by the sa~me poinlts w7ith but little aIppreciable wear. Thle cost of: resetting thle dliamondes so as to prescott nlew points is vrery slighlt, ~mdc n]o special skill is requliredl for thle op eration.. ~Il~ jfiB ~1iiii;~iiii1~ I I,~'I_____ ( Severance &~ Hrolt's Portable Prospctcing~ Drill. The speed of b~oring of course depeendls upon thne charlacter~ of the~ rockl, ranging fr~om five feelt per hlour il very. harad rncki to fifteen feet per: hlour in limestone, sandl rocki, and shrale. The ra~te of syPeed irn drilling apllpears~ to be limuited only by thze velocity w-ith w\Thichr it is p~ossible to r~otate the dirill. It is clarirmed th-nat wTithl one thouBsandi revoilntlons per mirnute the hanrdpest rock Inay be drilled fr~om eight to ten fLeet per hour, the diamond~rs cutting ornly the one-four-hundred~th par~t o~f a~n inrch at each revolut'rion, anld the drill thus adv\ancing one. inchn for every fonr~ hundred revolutions. Thris is the finest or slowest " a~~cl",nd is used only in flint or rockrs of greatest hlardiness; while in ordina~ry rock the drill is fed at thle rate of three hnundrved revolutions to the inch —the dliamuonds, of course, cuttingc~ the cne-threeii-hu~ndrcdth part of an1 inch at each revolution; and~ in marble, sandstone, &cC., at the rate of' an inch. for every twio hundiredl rev~olutionls. Thme pre~ssu~re of thre bit or drill head a:lgainst thle rock does nlott dependl uponz the length aLnd weight of the drill r~od, andc is no greater at the depath of a hundcredl feet than w~hen entering the rock aLt the snrfhace. The variationis in the feed are e~ffected by shuply changing one gear~wheel, requnirinhg less tha~n five mHinutes' tu~ne. The same mabchine wrill boure holes fr~om one to four inches in diametei, a~s desired. Th~e dii~amond tee~th are, the only parts of the tool wrhich come in contact, with thre rocki, aiid their hardlness is suc-h that more thanL1 two tlou — sand feet have been drilled bny the sa~me points writh buat little appreciatble w-ear. The cost of resetting. the dliamondls so as to l~rese~lt neor poi;~t5 is very~ slight, and no speciatlb skill is required for th~e operation. 52 MECHANICAL APPLIANCES 01F MIRING. Other re)lairs are seldom needed. The diamonds vary in prlice from six to seven dollars per carat, gold. Some of them are light-colored, translutcent stones, nearly one-quarter of an inch in diameter. The usual diamleter of bits for drilling blast holes inl mines is one and a half inch, carrying -ix diclinonds. _ _ _ i-l il _ _ _ _;'I l__i____ Open Cut or Quarry Drill. The peculiar slhape of the boring bit prevtents the drill fromn ruinning out of line; hence the hole bored, however deep it may be, is perfectly straight alid there is no firiction of the drill against the rock. The manufacturers have made another boring head of simnilar const-ruction, but having the annular opening pIartially closed and the diamlloalds so arranged as to bore out tlhe entire hole instead of producing the core. This formu of bit, however, is n ot desirable, as it requires far inore power to drive it, consumes niore diamonds, and is not available MACHINES }'OR DRILLING ROCKS. 53 for boring deep holes on account of its tendency to deviate from a true line. The annular diamond drill has been used for testing the nature of the rocks at considerable depths in many places, and it is evidently destined to be of very great service to mining industry. Rock-cylinders or cores have been repeatedly taken out from a depth of 300 to 400 feet, and they give a perfect record of the succession of the rock deposits, or veins passed through. At the lead mines in St. Francis County, Missouri, test holes have been bored at several points from sixty-five to one hundred and fifty feet in depth, and have proved the existence of deposits of ore not before known. At the Portland, Connecticut, sandstone quarries, a test hole has been bored and cores obtained to a depth of 312 feet. In Essex Coilnty, New York, the drill has been used upon the ore-bed of WVitherbees, Sherman & Co., and gave a continuous core to a depth of 340 feet in very hard rock, and in the compact iron ore, thus showing the nature of the forumation to that depth. In Pennsylvania, at the William Penn Colliery, the drill has been used to prospect for the " Mammoth Vein." The drills were put into operation at the bottom of a shaft already sunk 170 feet. In six hours and forty-seven minutes, actual running time, the drill penetrated to an additional depth of 104 feet 11 inches. Of this, 46 feet and 1 inch was through slate and coal alternating and mixed, and 58 feet 10 inches through anthracite coal, the bed dipping at about 45 degrees. The average rate of boring was 3.06 inches per minute for the whole depth, or about 15~ feet an hour. The proprietors write: We are satisfied that wre could I-ave bored through hard rock at the same uniform rate, for the slate bored through contains 1" sulphur balls " of the size of a goose egg, and upward, of sulphuret of iron, of intense hardness, but which formed no more serious obstrnctions to the drill than the conglomerate rock. With the exception of one imlperfect diamlond, we could not perceive the least effect or abrasion on the surface of the diamonds, even with a magnifying glass. We afterward tried the same machine for boring blast holes in the coal at bottom of shaft with equally satisfactory results. The coal was such as experienced miners could drill five feet per hour in by hand; the machine bored it at the rate of twenty-two inches per minute, to the no small surprise of our veteran miners. It is found to work well upon hard trap rock, in which it is almost irmpossible to drill a hole of uniform size with hand drills, or to drill more than about ten feet in depth. In this rock, upon the New Haven and Williman,-tic railroad, it is found by experience that where only from 8 to 12 feet of drilling could be made by hland in one day by three men, working by the foot, a machine will drill from 30 to 36 feet. Two mnachines are used and they give holes two inches in diameter and uniform throughout their depth-from 18 to 30 feet. It is found very advantageous to drill from two to four holes and to explode the charges in them simultaneously. By boring five holes to the depth of the grade, and exploding the charges all at once by the battery, it is possible to remove twenty-four feet in length of the rock in the cut at one blast. Some interesting results have been obtained with the drill in submarine boring at Hell Gate. The reef of rock to be removed lies from twelve to twenty feet below the surface of the water at high tide. The nmachine was so placed, just above the water, upon a trestle-work or staging, that the drill could be placed in contact with the rock twelve feet below. The drill penetrated at the rate of 61 feet per hour, and two holes 32 feet deep and 2~ inches in diameter were drilled in a short time. Its performance at that place has given great satisfaction. The annexed figure shows the construction of a machine for drilling in mines or tunnels varying from. four to sixteen feet! high. It is ope MECHANICAL APPLIANCES OF MINING. rated by steam anld is portable, being nearly balainced upon the two wheels. By depressing the handcle H it call be trundled about. Vi )jII) llI DilX -ies jq! _________ _i'.,All IDianiond Drill for mines. The upright framle (E E) which supports the swivel drill-head with its gears and c(hill, is attached by hinge-l)lates to the top and bottoim of the driving shaft (F) and may be swung to the right or left, clescril)bing a seImIi-Ci'rcle. This permits drilling at.my angle of the horizontal arc thus described without moving the machine, and also Splacing the drill-rod close up to the side wall of the tunnel. The drill-head also slides up and downr this adjustable framue (E E) and can be secured at any point so as to bore a erpenlldicular row of horizontal holes, -without incurring' more than three or four minutes' delay in adjusting the drill to each successive hole. The drill itself with its feed-gears and sliding guide (0) may )be turned completely round by simply loosening a nut on the back of the swivel head so that the point of the drill shall describe a vertical circle, at any angle of which it will bore equally well. The two uprights (G G) are used to support the driving shaft, (F.) They are made of commlon hydraulic plipe, an(l may e lengthelnel or shortened at pleasure, accordiing to the heillht of the tunnel. The driving shaft (F) has a sliding gear attached by feather and spline adjustable at any positionl as shown in the cut. The sliding brace just beneath this gear is used to steady the driving shaft. Motion is communicated to this shaft by means of the gear at the bottom, (D.) The hollow framle posts (E E) are set firmly against the upper wall by means Of extension screws (N N) \which -may be run up two or three feet if desired. The engine, water apparatus, feed-gears and bit, are the same as in the prospecting drill, and the mode of operation is essentially the same. When it is desired to produce holes less than one or one and a quarter inches diameter, it is usual to set the diamonds so as to cut out all the rock, but otherwise the MACHINES FOR DRILLING ROCKS. 55 annular bit is preferable. The steam or compressed air is brought through rul)ber hose from any convenient, distance and introduced into the engine by pipe, (L.) (AI) is the exhaust pipe. This drill being used to' bore shorlt holes, may be run nluch falster than the other, 900 revolutions per minute being a fair rate of speed. The feed may be varied at pleasure, and according to the hardness of the rock from 90 to 340 revolutions per inch, which gives froi two to ten inches per minute. The same advantages are secured by friction feed in this drill as in the larger one. The Leschot drill has recently been introduced in California and is in practical operation in Colorado Territory, at Clinton Gulch, in a tttlnel belonging to the Consolidated Bullion and Incas Mining Company. It was desired to prove the ground in advance of the end of the prospecting tunnel, 6(}0 feet long, and by means of the drill a hole was made 4171 feet, horizontally, in advance, and a core brought out so as to show the nature of the rock for the whole distance. The machine was placed inl the tunnel 600 feet from the outer air anld was moved by compressed air, supplied fromn a compressdr outside. At Shenandoah, Schuylkill County, Pennsylvania, the drill hlas bored a hole 274 feet deep, through shale, sandstone, and coal, at the rate of fromn 20 to 25 feet a dtay, including the time occupied inl taking out the core. Where it is not essential to obtain a test core, a much more rapid rate of progress may be attained. DE LA ROCdHE-TOLLAY AND PERRET'S BORING APPARATUS. In France considerable attentionI has been givenI to perfectinll ma. chinery for supporting in the proper positions and giving motion to the di-amond drill, a nd at the Paris Universal Exposition of 1867 the drill couldl be seen daily in operation, driven by water power and boring holes into the hardest granite. The motor was a small water-pressure engine, contrived llby Mr. Perret, of Bordeaux. This consists of a brass cylinder, 0'm1..055 inside diameter, in whiclh a piston works back and forth by the alternate pressure of the water onl the faces. The length of stroke was 0ill.120, and the motion was changed from reciprocating to rotary by a connecting ro(l and crank. It was run with nwater, the pressure of which varied fronm 3 to 9~ atmospheres; and it is claimed that under the maximum pressure from 47 to 57 per cent. of the theoretical effect was realized. The drill-bar consists of a six-sided cast-steel shaft, 11'1.45 long, bored throughout its entire length with a hole 0'1.016 in diameter. The diamlond-armeed ring is mounted upon one end of this hollow hexagonlal drill-bar, anld at the other end is a brass piston, 01'.11 in diameter, 1u)o01 which the water is allowed to press, so as to keep the ring firmily against the face of the rock to be bored. This pressure is varied with the harldness of the rock. A pressure of eight atmospheres is sufficient for a:ltrd roe ks, such as quartz and granite. For calcareous rocks, such as 1hiestones and marbles, five or six atm1ospheres is sufficient. The tool mnalkes about 200 revolutions a minute. By the injection of water through the hollow drill-bar the powder of the rock is washed out as fast as formed and the drill is kept cool. The drill-bar receives its mlotion -)Sbyr means 0of bevel gearing. The following are some of the results of the experimenlts made during the progress of the Exposition. The pressure upon the feedinlg or advancing pistolL, forcing the drill forward, was equal to eight atmlospheres, and tlhe speed of rotation varied from 200 to 280 revolutions per minute. The rate of advance was as follows: In solid Mount Cenis quartz.................. 01".054 per minute. In Morvan porphyries........................ 0-m.042 per uminute. 56 MECHANICAL APPLIANCES OF MINING. In granite......-........................ m.050 per minute. In hard calcareous dolomite...................... Om.080 per minute. The holes were cylindrical, and the sides were left quite smooth, and were thus very well adapted to the use of cartridges. The weight of the aplparatus is equal to that of the percussive drilling machines used at Mont Cenis-about 200 kilograms —and its price, inleludindg the engine but not the support, is 2,500 francs. It bores holes 0O.035 to 01'.06 in diameter and from 0m1.90 to 1%.00 deep. The ring used was 0'1.035 outside diameter and the core left was 0"'.014 in diameter. In regard to the cost of the diamond drill or the cost and wear of the diamond, it is stated in -the reports upon the Exposition: It is true that when the ring was first used a difficulty existed in the selection of the diamonds, as to which, from the nature of their cleavage, would be the most serviceable. The setting was not always performed as solidly as could be desired; but these difficulties have disappeared. We have examined two rings which were worked for seven months at the Exposition, and which have perfectly resisted. We believe that we can affirm that in a hard stone like granite, a ring properly worked will cut holes to an aggregwate depth of 150 metres. A rilng for boring holes 0"'.036 diameter costs about 150 francs, but as the black and opaque dliamonds used in its construction are ordinarily employed in the shape of (Iust for polishinll transparent diamonds, an(d as their wear dnlring the act of perforation is very slight, they can be extracted from the socket in which they are set, andl be returned to the trade Awith a odepreciation proportionate only to the diminution of weight. The diamonds extracted from a -\worn-out ringl generally feitch from seventy to eighty francs-that is to say, about one-half of their first cost. It is the opinion of Messrs. Huet and Geyler, who, with Mr. D'Aligny`, reported upon this drilling machine, that it must, in time, supersede the percussion drills; and they are confident that it could be used mIlost advantageously to replace the percussion drills at Miont Cenis. They remark: We cannot refrain from mIaking a comparison between this perforator and the one emnployed at Monlt Cenis. Its solidity, proved by seven mionths' work, gives the assulrance thact twenty to twenty-two of these perforators would be sufficient for the heads of both galleries, including duplicates, instead of at least two hundred and twenty actually existingr. Mr. Somnleiller's perforators cost the same as those of Messrs. IDe La Roche-Tollay and Perret. The staff would be four times less, for one man can1 easily attend four perforators; thnus four men instead of sixteen would suffice for twentyfour hours at the two galleries. The repairs to the rings require neither forfges, lathes, nor workshops; and we are coInvinced that a workman to each gallery would be sufficient for the repairs of all the perforators. WTe have stated that the rate of advance in the Molt Cenis quartz wasl 0.0v54 per linlute, under a pressure of 874 kilogralumes on the propelling piston; therefore a hole Omr.90 could have been driven in 16 minutes, say 20, and as each perforator slloldlil niake 10 holes, say 3~ hours, even doubling this time for preparing the work, it will be seen that five stopes can be done in two days, includilng the tiime for blasting and clearing awa, y the debris, which is equivalent to an advance of 2m1.25 per dieml, instead of barely 0Dm.50, the actual rate of advance. Thle apparatus of Messrs. De La Roche-Tollay and Perret is not subjected to any shock; thlle pressure is exerted on the rock irrespective of the speed of the tool, and such pressure can be regulated as may be desired; and when water power is obtainable, which is generally the case in mines and tunnels, the motive power actually costs nothilln Mr. Perret's machine can also be worked by compressed air, and for this it would be sulfiqcielt to add:a hydraulic accumulator to the perforator carriage. Such an accumulator would be but small, since the volunme of water i'equired for advancing the piston one meter is 9~ litres, it would be sufficient to add two or three litres per hole one, mneter deep for washing out the holes. VALUE OF THE ANNULAR DRILL. A conviction of the very great value of the diamond drills, especially as now made and worked by Messrs. Severance & Holt, imust be the excuse, if any is necessary, for giving so much space to the description BORING DEEP WELLS. 57 of themn. After ihaving seen the operation of the drills, and the great variety of samples of cores of the hard rocks, such as syuenite, granite, trap, compact quartz, magnetic iron ore, marble, &c., which have been taken out by their nse, andl after reading many of the letters from various parts of the country, giving the most satisfactory reports of the operation of the drill in prospecting and in quarrying, I anm satisfied that it should be commended to the attention of miners and prospectors everywhere, as one of the greatest aids they can have in ascertaining the nature of veins and beds at considerable distances, either from the sutrface or from the deepest or remotest points reached in their mines. The prospective value of many mines may, by means of this drill, be very closely and economically ascertained. It may be made of immense service not only in mines where the veils are pinclled and of doubtful value, butt in those veins that have always been of good size and vstlue. It would, for example, be important and highly satisfactory to ascertain whether the rich vein of the Eureka Miine, at Grass Valley, California, continues to have nearly the same character and gold-bearing value for 400 or 500 feet below the present workings. The shafts and preparationls for working could thlle with grea~t propriety be projected tupon a scale comnmensurate with the work evidently to be done. So, also, in respeet to the Amnador Mine, Sutter Creek, the Sierra Buttes, and other noted mines of California, and the Comstock lode inl Nevada. There is atleast one promlinent case where this testing drill could be made of great service-at the Princeton vein, on the AMariposa Estate. The shoot of ore in this vein plunges at an angle of about 170 to the southeast, andcl has been worked about as far as it can be economically in that direction; and it is very dcesirable to know whether the shoot continues with the same inclinationm and richness far beyond the present excavations. If it does, it will be advisable to sink another shaft to intersect that part of the lode. A test hole could be sunk in a few weeks by means of this drill, and a core, showing the thickness and nature of the vein at that point obtained at trifling expense, compared with the cost of sinking a shaft or running a tunnel. It is probable that the annular diamond drill may be advantageously used for cutting shafts of large diameter, inasimuch as the ratio of the quantity of material cut away to the size of the hole bored becomes less and less as the diameter of the bore increases. A large core would be left, but this could be readily broken out by blasting in a central hole. Among the great advantages of such shafts would be their truly cylindrical form and smooth sides. CHAPTER V. BORING DEEP WELLS FOR WATER OR OIL. Within ten years seventy-five artesian wells have been bored in the desert of Sahara, yielding in the aggregate 45,000 litres of water per minute, or 64,800 cubic metres in twenty-four hours. A part of this desert has been made fertile; two -villages have been created in the midst of the former solitudes, and 150,000 palm trees have been planted in more than a thousarnd new gardens. This is an indication of the great results in store for those who may undertake the work of supplying water to the marvelously rich soil of the Colorado desert in California. The strong arml of the government should be reached out in the initia-. 58 MECHANICAL APPLIANCES OF MINING. tive to restore fertility to such a broad area of the public lands, now not only worthless but a positive barrier to the settlement of that part of the country, and to transportation between the coast region and tlie interior. Artesian well-boring has been practiced in California since about 1852, when several wells were pierced in the recent strata overlying tile rock formations of San Francisco. Since then a great number of borings in the Santa Clara and Sanll Jose valleys, and in other portions of the State, have been very successful. At Stockton a well has been pierced to a great depth, and an abundant supply of potable water obtained, whiclL rises above the surftace and supplies the city. The great trough'-like valleys and basin-shaped depressions throughout California, Nevada, and iudjoining regiols present conditions favorable to the success of artesian borings; and although an overflowing fountain cannot in all cases be,xpected, yet there is little reason to doubt that an abundant supply may be obtained from the borings by pumping. The Sacramlento, San Joaquin, and Tulare valleys, all invite a resort to artesian borings for water to irrigate their lower and more, arid, portions, where in mnid-sunminer the drought is excessive. The Colorado desert, already mentionedl, is another region where artesian borings may supply the only requisite for extreme fertility. The most simple and the most ancient form of ap11paratus for piercing the earth to great depths is that adopted by the Chlinese. It consists of a rope arnied at the lower end with a tool of iron or steel. W~e are indebted for some of the earliest infor-mation in detail upon this subject to the missionary, hnbert, in 1827, who reported that in the Province of Ou-Ton2g —Kiao there were many thousand borings within an area of four leagues by ten, carried to a depth of nearly 1,800 feet in search of saline water and petroleum. Some of these borings, after the exhaustion of their brine, had been pierced to the depth of 3,000 feet, and had reached sources of earbureted hydrogen gas, which was used to produce the heat necessary for the concentration of the saline water. A simple derrick, with a pulley above, and reel below fronm which the rope is unwound as the hole deepens, is nearly all that is required besides the perforating tools. Cords are attached by mleans of clamps to the rope between the pulley and the reel, and by pulling' upon these cords the dcrill is alternately raised and dropped. The vertical nmovement of the drill ranges fron one to two feet or more. The drills are made in various formls accordinlg to the nature of the rock to be penetrated. A French engineer, M. Jobard, uses a heavy cylindrical head of chilled cast iron attached to a long iron rod, as shown in section by the figure. The extremity of this rod is armed with a steel point, which projects below thle cutting face of the cylinder, and serves to center the hole like the point of a carpenter's cellter-bit. The surface of this cylindrical drill-head is channeled, so as to give room for the powder formed by the cutting to rise around it, and the upper part is provided with a conical cavity, c c, inlto 1 which the loosened materials fall, and are removed from the hole when the drill is drawn out. The small figure, d, below the seetion, is a view of the end of the drill, and shows the arranlgemlent of the cutting edges and grooves. Th'1e rod a ay be several yards long, and is provided at the top with cross-bars of steel, b, intended to act as guides to keep the tool vertical. If it is deiy sired to make the hole larger, in order to introduce tubing, it is BORING DEEP WELLS. 59 only necessary to suspend the tool a little to one side of the axis, it will then hang with more less inclination in the hole, and cut out the sides in its descent. This would not be safe in loose rock. Another form of drill was designed and has been most snecessfully used by M. Goulet-Collet, of Rheims. It consists of U a cylinder of heavy sheet-iron, two metres in length, suslpenlded by a chain, and armed at its lower end with an annular cutting head of steel, a, in which two knives or chisels are placed across the opening, as shown in the end view at b. These chisels serve 7r to cut the rock, while the water and sand are free to rise through fl the cylinder. The removal of the debris is effected by another tool, although this cylinder may be provided with valves like a sand-pump, and thus serve the double purpose of drill and pulmp. When the rocks are not too hard for this forlml of tool they may be pierced with great rapidity. According to M. Debette, from whose description the foregoing is compiled, 1V. Goulet-Collet, with two workmen, could borefrom eight to eleven metres a day in the chalk of the cretaceous formations of Champagne. He would also contract to bore wells to any required depth for nine francs per metre. He had made in the course of several years nearly one hundred borilgs, and each ha'd given good water, for a total cost ranging from 150 to 300 francs. The apparatus did not cost over 500 francs. The methods of boring employed in California are substantially the same as those for oil wells, to be hereafter described. The rope, is used in preference to rods, and there is no peculiarity in the method worthy of special notice. In Europe boring with rods rather than rope is preferred. These rods are made of elastic wood, or of the best quality of iron. In the latter case the sectional area depends upon the depth to which the hole is to be bored, varying as shown by the annexed table: Diamleter of Sectional,area| Depth of hole. hole of rods. Mefetres. ilief'es. etretres. 0 to 50 0.05 to 0. 6 0.025! 1 50 to 100 0.06 to 0.10 0.030 1 100 to 200 0.10 to 0.15 0.032 200Cl and beyond. 0.15 to 0.25 0.045 At Cessingen a well has been bored to a depth of 535 metres, with. rods of 011.025 section. The length of rods is limited only by the height of the derricks. It is usually between four and eight metres. As already remarked, great inmprovements have of late been made in the apparatus for boring to great depths, and especially for sinking wells several feet in diameter. The success attending the boring of the celebrated well at Grenelle, Paris, has led to the sinking of still larger ones, in order to give a more abundant supply of water and meet the necessities of a rapidly increasing population. In 1867 two wells were in progriess-one in the suburb of La Chapelle, in the northern portion of the city of Paris, by MM. Degousee and Laurent, and the other at; Butte-aux-Cailles, in the extreme south of the city, by MI. Drmu, forinerly 3Mulot & Dru. These new wells were to be, the one five feet in dialmeter, and the other about four feet. The following are the depths and dimensious of the older wells: Height above tile sea, at Grenelle, 60 MECIIANICAL APPLIANCES OF MINING. 121.3 feet; at Passy, 305.2 feet; depth of bore-hole, at Grenelle, 1800.7 feet; at Passy, 1923.7 feet: internal diameter of tube, or lining of hole, at Grenelle, approximately, 9 inches to 6 inches at bottom; at Passy, 2.4 feet. The full diameter of the Passy bore-hole was one metre, or 3.28 English feet. The Universal Exposition of 18679 at Paris, contained fine illustrative specimens of the tools and apparatus now used by MTessrs. Degousee and Ch. Laurent. In the notice of them, and of the operations of boring which follows, I hav e used not only my own notes, made upon the spot, but portions of the report of the United States commissioner to the Exposition. The apparatus, doubtless, does not present, for the most part, the interest of a new invention; but in examining the details of its construction, it is easy to see that the novel and diversified condition in which tle sinkings have been executed, and the unforeseen accidents which these have prodnced, have been studied with great care and intellicence by- these able engineers, and that all the teachings of practice have been profited by and have led to many important modifications and simplifications of the forms of the tools. The boring rods applicable to artesian wells, before the wells of Passy were sunk, (lid not exceed 01".30 in diameter. The two wells undertaken by the city of Paris —one at La Chapelle, by Messrs. Degousee and Ch. Laurent, the other at La Butte-aux-Cailles, near the Ivry station, by Messrs. Drau Brothers —have been comnlenced at a diameter of 1111.80. The boring apparatus comprises two essential parts-the tools which serve to excavate the earth, and the appliances at the surtace for working or handling the tools, which become much more important as the diameter of the wells or shafts is increased. The following are some of the details of the construction and dimensions of the tools used by MIessrs. Degousee and Ch. Laurent at the artesian wells of La Chapelle: The machine is worked by a horizontal steam-engine of 15 horsepower. The fly-wheel shaft makes 50 revolutions per minute. It carTies, first, a pinion of 0"1.30 diameter; secondly, two brakes; thirdly, two clutches; fourthly aind lastly, a pulley of 1'11.50 diameter. The pinion of 0111.30 diameter drives a toothed wheel fixed on the axle of the drumI of the capstan, upon which the chains for lifting the shafts of the borers are wound, and also the percussion amld clelansing apparatus. The diameter of the drum of the capstan is 0'11.55; its length -is 11.60. It has a, spiral groove which guides the chains and causes themn to wind regularly upon it. The pulley of 1111.50 diameter is belted to another pulley of 1111.00 diameter, fixed at the extremity of an axle which carries at the other end a pinion 0111.40 diameter. This pinion is geared with a wheel of 2111.00 diameter, fixed on a second axle, where is also fixed the crank-plate which, by means of a connectiig rod, gives a reciprocating motion to the striking beam. This beam is supported at a point about two-thirds of its whole length distant from the connecting-rod end. The two clutches mentioned serve, on one part, to throw into gear the pinion of 0111.30 "with the driving wheel of the drum of the capstan, and, on the other part, to drive the pulley of lm11.50 diameter, keyed on the fly-wheel shaft, by which motion is given to the striking beam, at the end of which the boring tools a-re attached. The two brakes placed upon the fly-wheel shaft are for the purpose of regulating the speed of the descent of the tools, the weight of which BORING DEEP WELLS. 61 might cause a great acceleration of speed, and, conseqLently a fratere, which is always to be dreaded. The timber framing which forms the derrick or tower for the sinking of the wells is more simply arranged than that adopted by Mr. Kind in, his construction for sinking large shafts. The tools, in place of being received upon a platform about ten metres above the surface, are upon the surface itself, and it is, consequently, munch more easy to work them.l The linked chain for lifting the tools has stood the wear of ten years without any accident; while the breaking of the cables employed in the system of Messrs. Kind and Chaudron have occasioned serious accidents and delays. At the boring of the wells of Passy, undertaken by Mr. Kind, there were two machines of 25 horse-power, one of 10 horse-power working the striking beam, and one of 15 horse-power working the capstan drumn The trepan, at the shank, did not weigh more than about two tons. Messrs. Degouse and Ch. Laurent used an engine of only 15 horse-power to work their trepan, which weighed about four tons, and to bring the broken or bored earth to the surface. This engine did not require any repairs, except such as are ordinarily necessary during a service of two years. BORING TOOLS OF DEGOUSIBE AND LAURENT. The construction of the trepan employed at the artesian well of La Chapelle differs completely from that of Mr. Kilnd. It is composed of six branches, so arranged as to break up the earth in an annular belt or zone, leaving a central core. The six teeth, which are keyed into the blade-holder, are 0n.35 wide, and the mode of fixing them into the six branches is so secure and solid that, up to this date, no accident has, happened. Even when a tooth becomes unkeyed it cannot get out of the blade-holder, while at the shaft of the Hopital there have been twenty-three teeth out of their sockets, all of which fell into the slaft. One of these accidents caused a sto)page of a month. The percussion of the trepan with the regular rotating lmovement cut:-t out an annular channel of 0'1.45 to 01'.50 large, leaving in the celnter of the shaft an unworked piece of earth, or core, of 0111.80 or 011.90 diameter. This mass, when in slightly coherent earth, crmnbles cdown and formls an irregular cone. In this case they bolt on one side of the center of the tool a radial or a trmlsverse blade, which triturates the core. This trepan weighs about four tons. Its first cost is greater than that of Mr. Kind's, but it proves in practice to be much more solid and durable, andcl it works better. )Messrs. Degouse', and Ch. Laurent have been very successful in givin g a free fall or drop to their trepan. WVith more than ten thousand blows, thel trepan has not once failed to be caught again upon the descent of the rods, and its fall has always worked with the greatest regularity, while at the shaft of the Hapital eighteen fractures of pieces of the slide have occasioned a stoppage of more than a month. The contrivanice for the free fall of the trepan is constructed as follows: A movable piece surrounds the shaft above the hooks and terminates in a fork, of which the two branches extend below the cutters and touch the bottom of the bore. This piece is not lifted, unless the borer is raflsed more than tIle stroke allowTed by the collar which attaches around the hooks. The upper part of the hooks lifted by the boring rod slides, therefore, in the collar, and, meeting a striker whllich makes them open, the tool immuediately falls with all its weight on the bottom of the bore. 62 MECHANICAL APPLIANCES OF MINING. The boring rod, being lowered, dcatches the tool again by the hooks, and:this action is repeated so as to obtain a succession of blows. The suspension rods employed by Mtessrs. Degousee and Ch. Laurent are of iron. They have a section of 0111.045 square, and are 12'11.00 long. These rods have worked for two years without accident, and they are better thain those made of wood, for the following reasons: It is evident that wood alt a great dcepth w ill acquire from the pressure of the water a density at least equal to that of the water; and, moreover, the iron fittings add to the weight in a certain proportion; and if we compare the sections of the shafts or wooden rods of the wells at the H10pital with those of iron at the wells of La Chapelle, it is seen that the metre in length of the first weighs at least 3i5 kilograms, (70 pounds,) while that of the second does not exceed 16 kilogramls, (32 pounds.) It is true that, as the wooden rods displace a greater quantity of water. their weight is diminished; but this small (advantage is largely overbalanced by their rapid deterioration, whether in store or at work. The wood in drying heats and loses its qualities. Well made, their construction appears sufficiently costly to make the matter of renlewing them at each sinking rather an important item; they augment sensibly the cost of work to be done. On the other hand, the iron shafts that can be balanced, as practiced by MAessrs. Degousee and Laurent, require for their descent and elevation but a little iore force, and witIt steam-engines this increase of expense is so little that'it may be disregarded. The draining and cleaning tools of the wells at La Chapelle differ equally from those of iMr. Kind, and they are, perhaps, superior. The modification of the trepan intended to work out the annular groove or zone led to a modification of the auger, which is annular and composed of nine augers joined together, of 0111.35 diameter. The sloon or bucket which lifts the detritus in the mniddle of the wells is a cylinder 1111.00 in diameter, and 2111.50 in height. The bottom, in place of carrying two valves, is pierced with seven round holes, which are closed by hemispherical hollow valves, carrying in. their axis a shaft which traverses the whole length of the spoon. This shaft is teraminatedc by a handle which permits the workmlen to lift up the valve in order to empty out the mud when the bucket is withdrawn fromn the well. This arrangoment is intended to obviate the inconvenience of the hinged valves, which often, by not completely closing, let the ma.tter in the bncket escape duri ng the ascent of the dredge. The bucket at La Chapelle is emptied with great ease, it being lifted one metre above the surface and placed on a little truck, which carries it immediately under a crane placed at the side where the contents are to be emptied. The recovering tools are composed sitlmply of the ordinary screw bell, (cloche i( vis,) a grapnel, and a new form of pincers, withll four branches. These four branches are arranged in a parallelogram a n d one of their ends is fixed to a single piece bored and tapped in its center. It is easy to understand the part this plays: in raising or lowering the nut in the screw, which is attached to the boring rods, the four branches expand or contract at will, and, resting on the bottom of the well, they seize the objects which may be there. TUBBING. The artesian well of La Chapelle traverses the Tertiary strata of the Paris basin, and penetrates the chalks and mlarls of the Secondary. According to the agreement between the contractors and the city, the BORING DEEP WELLS. 63 boring is expected to be 600 metres deep before it reaches the waterbearinlg bed of the green sand formation. After working two years, the well has already (1867) reached a depth of 337 metres, but it has been found necessary to tub or line the shaft to avoid the caving which would inevitably happen without it. A first column of sheet-iron lining, lm.80 dianeter, 34111.50 high, and weighing about thirty-six tons, was put in immediately below the preparatory pit, which last was lined with masonry to a distance of about six metres below the surface, where the working platform was placed. A second column, 1111.70 diameter, 135 metres high, and weighing 11 tons, was next put in; and lastly, a third column was put down jllst to the chalk. This column has a height of 139 metres, its diameter 11u.37, and its weight about 110 tons. The columns are made of sheet iron of a mean thickness of 0m.02; the height of each section being determined by the breadth of the iron plates. These plates were fastened together by rivets with countersunkl heads, so that the interior and exterior surface of the lining were quite smooth. To form one of these cylinders, two sheets of iron of the thickness of 0111.01 are taklen and riveted together in such a manner that one of them, the inner one for example, projects slightly beyond the other, and thus forms a shoulder to which the next section above can be riveted. By this arrangement it will be seen that each column of tubbing presented the same diameter throughout its length. When the sections of the column are thus prepared, they are lowered and put together as they descend into the well. This operation is performed in the following manner: A wooden frame is made and supported upon a wheeled truck. This frcame is composed of two strong vertical walls of a height of fout or five metres, connected at their upper part by a cap or top, to which four nuts are fixed to receive four screws intended to sustain the pipe in its descent. Each of these screws is worked by two men by means of a crank and bevel gearing conveniently arranged. The lower part of these four s1rews is fixed to a strong circular wooden plate, about 111.50 thick, and equal in diameter to the inner diameter of the columni that is to be lowered. Upon the working platform a species of tubbing in wood is placedl, the interior diameter of which is equal to the exterior of the iron tlbbing or cylinder. The height of this tubbing is two metres; the segments of which it is composed are united together, and can be drawn together or expanded by means of screws, so as to squeeze the column and act as a clamlip or support during its descent. When this kind of tubbing is put in place, and the friame which carries the screws is put in the axis of the well, the first section of pipe is brought forward and placed over the well. Previously several iron ears are bolted upon the interior face of the tulb, and about a imetre below its upper edge, the use of which will be presently explained. Other projecting ears are fixed in the inside of the tub, and on these ears the lower part of the wooden plate is allowed to rest, and is then bolted to them. When the work is thus prepared, this first tub is lowered until the outer ears rest upon the upper edge of the wooden tubbing which surrounds the column on the outside. The inside ears are then remloved and the pipe is supported upon the outer tub. The inner plate of wood is then lifted up by the aid of the screws, and the rivet holes of the ears are closed up by hot rivets with countersunk heads. The second cylinder is then placed in the axis of the well. This second cylinder has inside and outside ears like the first, and the circu 64 MECHANICAL APPLIANCES OF MINING. lar plate is introduced and bolted to the ears. These hold it at its upper part, and it is then lowered regularly, with the aid of the screws, until the lower part fits into the first cylinder. The two sections are then riveted together by hot rivets. The tub is then lifted a little in order to remove the outside ears of the first section of the cylinder, and the whole is allowed to descend by its own weight till the outer ears of the top cylinder rest in their turn npon the upper part of the wooden tubbing. They proceed in the same way for all the other sections of the column or tubbing of the well until it is finished. The lowerin.g screws are each calculated to withstand a strain of fifty:tons; but to prevent a too rapid descent of the lining when it has attained a considerable weight, Messrs. Degouse an(l Ch. Laurent make use of the species of tubbing upon the surface of the working pits already noticed. This tubbing not only serves to guide the column and to make it descend vertically, but also, and above all, to act as a powerful brake, mand thus enable the workmen to control the velocity of the descent at will. Tightening the segment screws gives a strong compression and friction over a height of two metres, sufficient to control the descent of the tubbing. The three columns of sheet-iron lining, which have been mentioned, were put in place by this system of operating with the greatest ease, at the rate of four metres a day, including the time spent in riveting the sections of the tubbing. When the artesian well of La Chapelle is sunk to the depth of 600 metres, a tub in one column will be lowered to the satue depth. MIessrs. Degousee and Ch. Laurent propose to employ the same method of lowering, and there is no doubt that these able engineers will succeed completely in this magnificent work. The false bottom bfor the tubbing, which is used by Messrs. Kind and Chaudron, would not answer in this case, because it would prevent the water from rising in the well. The work carried folrward at La Chapelie proves that by the system 5 niveau plein, of sinking from the surface, large shafts for mines can be executed by the tools and method of Messrs. Degous6e and Ch. Laurent with great success in similar formations. At the well bored by the Messrs. Drin, the depth at the end of April, 1_867, was nearly 500 feet. The weight of the boring tool was over 2 tons 18 cwt. The rods were, for the most part, of wood, with iron conneetions, and 10 metres long; two rods, or a length of 201', were raised and lowered together. BORING FOI, COAL. One great use of boring apparatus abroad is, to ascertain the thickhess and nature of the strata that over-lie coal [eds, and thus to know the position of the coal and the probable difficulties and expense of sink-'ing shafts to reach the beds. Itis also employed to ascertain the nature of the faults and dislocations of the beds; the extent of ancient pits and workings, and to drain such places by piercing to them in advance of the new galleries. In the coal district at Zwickau, Satxony, mining concessions are not granted until coal has been discovered by a bore hole or other means. The Briickenberg company prospected their ground by boring to a depth of 363 fins. before they found coal. The following are the dimensions of the hole in Saxon measure: Diameter. 1st 24 feet ----- -.................... 6 feet. 265 feet.-2......-........................ 20 inches. 180 fet... —...... 18 inches. 28}inhs BORING FOR PETROLEUM. 65 Diameter. 315 feet...........-........... 171 inches. 440 feet......................................... 15, inches. 360 feet -........................................... 14 inches. 250 feet -1................... - -. -.. 124 inches. 122 feet —-----.11.. —------ inches. 198 feet......in...c............................. 10 inches. 73 feet.................................................. 8 inches. 47 feet................................................ 7 inches. 50 feet-.........6................... G inches. For many such operations, the diamond drill, already fully discussed, may be found superior to the apparatus ordinarily employed. BORING FOR OIL. The discovery of petroleum in quantities in Western Pennsylvania, West Virginia, Ohio, Canada, and other localities, has given a great development to the art of wellboring in the United States. The cumlbrous pole-tools htve been rejected, and the cable, upon the ancient Chinese systemr, substituted. The great advance has been in the construction of the tools, and in the adoption of simple apparatus for giving mnotion to the drill by means of steam-power. For prospecting and for sinking to moderate depths of 50 to 150 feet, the spring-pole, worked by hand, is frequently employed. This was the apparatus chiefly used in California a few years since, when the oil regions were prospected. The constructions in common use in Pennsylvania at the oil-wells and -used for a time during the oil excitement in, California, consists of a derrick, bullwheel, band-wheel, sansom-post, and walking-beam, and a portable steam-engine. The descriptions and g dimensions given below represent the average as determined by experience. The derricks are usually constructed of plank and boards, when they can be obtained. or of unhewed poles. They rise to a height of 50 to 60 feet, and taper upward from a base about 15 feet square. dN i The standards are of two-inch plank, 8 inches wide, and the cross-braces 8 inlches wide and 1 inch thick. The tools are suspended by the cable, which, passing over the pully at the top, descends at the side, and is wound upon the drum of the i bull-wheel, the shaft of which rest on bearings in the standards. The drum of the bull-wheel is I about 10 inches in diameter. The walking-beam, of wood, 26 feet long, is supported at the center upon the top of the sansomn- it post. One end is connected by a pitnman, with a crank of 22 inches radius, upon the end of a shaft receiving imotion by a belt from the engine; the Rope other end, projecting within the derrick and diSocket. rectly over the well, carries, suspended, the tem- Temper Screw. 5M 66 MECHANICAL APPLIANCES OF MINING. per-screw, to nThiclh is attached a clamlup for seizing -uponl the rope. IThe rotation of the crank-shaft givies a reciprocatillg motiolI to the end of the beamn, and this is imparted to the rope, carrying the tools at its lower end. I' The form. of' the tenmper-screw is shown by the figure. By this the drill imay be lowered! or "fed out" to a certain extent during the progress of boring. The rope is seized and I length of the screw is fed out the position of the clamp is changed. The drilling tools consist of center-bits, realmers, an anger-stem, sinker-bar, and the il [t',!'l jar" besides a socket for attaching them to the lower end of the rope, and wrenches, l land other accessories to aid in attaching l ai nuin sllcIISC rewilg the bits. There are, besides il a variety of tools for recovering broken bits i 1or othter parts of the apparatuts lost in the w 111vell, and saind pumps fo)r removing the ddbris. The bits are represented by the aunexedi and the' rearLners are 4,t inches. They are i mil|mlade, however, of various sizes, and all lhave i!strong square shanks, so that they mlay bei,ifirtmly screwed into the auger-stem, made ofi 22 inch iron anrd 20 feet long. The " jar" is a contrivance by which the auger-stem and bit is, in a measure, dieIItaclhed from the rope. By it a blow or sud-'den jerk may be given upwards so as to The Wyrenchles. l same device serves to give a blow downward 1upon the auger, l after the bit strikes the bottom, thus doubling the efficiency of YUU1liIThe Jar. 1111II['Il', i13ts andl Reamer for drilling. each stroke. It serves also to maintain the tension of the rope drilng the stroke. These jars are made of 1-inchll iron on the sides7 with 12inch heads, and 18-inch stroke. The sinker-bar, 10 feet lolg, is attached by a screw to the upper end BORING FOR PETROLEUM. 67 of the jar, and above this is the rope-socket, securely united by means of rivets to the end of the rope. The bits and other parts of the drilling tools are connected and clP disconnected by means of two large wrenches, 3 feet 9 inches long, with broad flat heads, shaped as showni1 in the figures. The drilling ropes or cables vary froml 14- inch to 1a inch diameter, and weigh from 48 pounds to 86 pounds per 100 feet. The sand pumips made of heavy sheet-iron, or of galvanized iron, sometimes of copper; are: about 5 feet long, and from 3 inclhes to 4 I I inches in ciameter, and are fitted with leather valves resting upon iroi seats as idlcicated at the lower eind of the figure. i i:lri}} These tools, and the iron fittings for the 1i oalkinr-le, amid eels, alld other prts of Ip s I1I!i the apparat-us for wvell-boring, are mlanuface- li0 i tured by- Messrs. Hart, Ball & Hart, of Buf-, i fll' ojl, New York, to whom I am indebted for 1iltI the illustrations. The steam-engines in use Fill 1l{i'l~ are portable~ and generally fronm 8 to 10 ll horse-power. A 900-foot well canl be drilled with an 8 horse-power engine. Rope for wf ell 900 feet deep, with thle tools, wrill weigh!!il?!0 ~aborut 800 pounds. i Before colmmencing to drill it is usual to ill | 1t dlrive down a cast-iron pipe tllrouglh thle F Wi loose soil and alluvial dep)ositS unltil the' l i firm bedl-rock is reached. These pipes are aI adle in lengths of eight feet, ancd are fiom i, f oeive to si ilnches in diamleter. Thev are',i!i I 7 I1] rou 0ght-iron batnds catrefill welded and 3!'?!t i! Ilj~il sized to shhitlk 011 to a siouldcler tulrnecld upo eacll en d of the pipe in a lathe, so tlhat a flush joint is formled by the band. iit!I Time lower end is made sharp, andl the band i l is ecdged. with steel. This -form of jointl has b eenl paitenle by Mr. B elles, whlose namie it ll |bears, andl it gives great satisfactiom. The five-inch lenagt.hs weigh 55 pounds per foot, I i i or 440 poundIls iln all; andt the six-inclh 69 pounds per foot, or 552 pouinds per lengtlh. For lininlg the wrells wroughlt-iron tublillg is FF iiIused, made with screws aud sockets or with flush joints, but always smooth-finished in- Iii1 side. The sizes vary. For the light kinds, froF m one and a half to four inches for the Ji}'l inside diamleter, and firon 1.66 pound to 6 poi tm' peounds per foot. The heavier tubing ra1gtes Sand from one and a half inches in diamneter, anid StufEng Box. Oil Pump. Pump. 2.70 pounds per foot, to 6 inches, -weighinig 18.7 pounds per foot. These large sizes are seldom used for oil wells. Pumps are made of wrought-iron pipe lilled with heavy seamless brass tubes bored perfectly true, or of heavy brass tube alone. One of the last-mentionedl construction, five feet long-, is shown by the annexed 68 MECHANICAL APPLIANCES OF MINING. figure, in wY'lich a portion of the interior is seen with the two valves and boxes. These valves are made of gun-metal, and are fitted with great care. The packing is made of the best oak-tanned leather. Ball valves are generally used. The pump here represented is nmanufactured by the Messrs. Hart, and they have made an improvement upon the ordinary construction, by which the lower ball valve may be loosened from the top of the guard over the valve seat, to which it sometimes becomes attached by the accumulation of a deposit. A projecting point at the bottom of the upper box enters the hole in the top of the lower box, and thus forces down the ball. The portion of this projection nearest to the box has a screw thread cut upon it, and may be screwed into the box below, so that they may both be drawn out together. The pump barrels are usually five feet in length. At the top of the well a stuffing box and elbow pipe is fitted. The construction of this box and the form of the joint for attaching to the sucker rods is shown in the figure. The stuffing is kept in place and is pressed firmlny upon the pllunger-rod or piston by means of the follower, made of brass. The plunger-rods are five feet long, are made of oneinch d-i:i:-eter cold-rolled iron, and are perfectly polished. One other important adjunct of a complete oil well is the seed-bag, the use of which is to form a water-tight joint or packing around the tube or lining of the well, and thus shut off all communication between the water of the upper strata and the oil-bearing crevices or chambers below. This bag is made of leather, and is filled with flax-seed. It is put around the tube and is pushed down to the proper place, and soon becomes so much swollen by the absorption of water, that it fills the space between the tube and the walls perfectly, and shuts off all comlmunication around the tubing for either water or oil from above or below. THE A3MERICAN TUBULAR WELL. A very expeditious and simple apparatus for obtaining water, where it is not at very great depths below the surface, and in alluvial soil, is here worthy of mention. It is known as the tubular pump, or tubular n-ell, and consists merely of a wrought-iron tube an inch or two in diameter, which forms the pump barrel. This is fitted with a valve near the bottom, and tipped at the end by a sharp-pointed steel plug. This sharp point permits the whole tube to be driven down into the soil until the watery ground is reached, when, by raising the pipe a few inches, the plug, is detachedl, and the lower end of the pipe is left open, while, at the same time, a small water chamber is formed. By inserting a pump-rod, with a lift-box, water may be pumped to the surface inl a continuous stream. This simple pump has worked well in sandy and gravelly soils, and is said to have been of great service to the British forces in Abyssinia. It could doubtless be used to great advantage in many places throughout the Great Basin and in California. CHAPTER VI. BORING LARGE MINING SHAFTS. The methods of boring shafts of large diameter have of late years been carried to great perfection abroad, especially inl France and Belginum, and there is little doubt that they might be introduced with advantage BORING LARGE MINING SHAFTS. 69 in some sections of the western coal-fields; and perhaps, also, in the metalliferous regions among the harder metamorphic rocks. It is therefore deemled appropriate to give a short description of these methods and of some of the great results which have been achieved. Probably the most important advance in the art of inining, of late years, is in the sinking of large shafts by boring. Boring into the earth to great depths is no longer confined to explorations in search of water or oil, liquids which will freely flow out in quaintity through small openings, but it is now resorted to for the construction of deep shafts through which solids, such as coal and metallic ores, are to be hoisted. Even artesian borings have been increased in size until they resemble rather mining shafts than the former borings, only a few inches in dialneter. The art of boring has received a great impetus from the necessity of boring larger and deeper wells for the supply of the city of Paris with water. Several wells have been commencel with a diaimeter of mnore than three feet, accounts of which were given in a former chapter. In order to bore shafts and wells of such great diaimeter it is necessary to use tools of imlense size, weight, and strength, and steam-power to move and work them. The great improvements are due chiefly to M1essrs. Fantet, Dru, Degousee and Mulot, in France; Sello, Kind, and Oeynhausen, in Germany; Jobard, Guibal, and Chaludron, in Belgium. The most striking feature, next to boring, of this system of shaftsinking, is that the work is executed and the shaft is lined without pumping the water out of the excavation. The sinking proceeds under water, and the shaft is not drained or entered by miners until it is completed and lined from top to bottom. The method thus finds the most useful application in regions where the strata to be passed through are highly charged with water, andl, in fact, it owes its perfection to the necessity of penetrating through watery and difficult ground in the northern French coal-fields. The expense and extreme difficulty attending such operations in the ordinary way is well known. Burat estimates that a capital of upwards of 8600:000 is expended in opening a coal mine with a productive capacity of 100,000 tons annually. Examples of a still greater outlay are not wanting. WVarrington Smytlh, the great British professional authority upon mining, states that, in consequence'of the difficulty of piercing through the strata overlying the coal in Durham, England, sumns of ~40,000, ~60,000, and, it is even said, ~100,000, have been expended on a single shaft. As early as 1860 M. Chandron succeeded in sinking an air-shaft at Peronnes, where the watery beds extended from the 43d metre to 105 metres in depth; and'M. de Vaux, inspector general of mines, Belgium, reported in 1861 that the work had been executed for less than onequarter of what it would have cost if sunk in thle ordinary way. In the coal basin of Sa.arbruck, in the north of France, at L'H6pital, the Saint Avold Company desired to sink two shafts, one for ventilation, and the other for extraction. There were 150 metres in thickness of Avaterbearing strata to be passed through. After numerous unsuccessful efforts before the year 1858, and an expenditure of more than 21,000,000 francs, about $4,200,000, the attempt to execute the work in the ordinary manner was abandoned, and recourse was had to the engineers Messrs. Kind and Chaundron, who, by the boring process c nivceaulzein, succeeded in sinking and lining the two shafts in the mlost satisfactory manner in less than thirty months, and at a, cost of less than 700,000 francs, which includes the cost of installation anld the tools-nearly one 70 MECHIANICAL APPLIANCES OF MINING. seventh of the whole sum. The tools used in this work, and sections of the cast-iron lining or tubing, were exhibited at the Exposition of 1867, and have been reported upon in the series of reports by the UnVited States commissioners. They are also described in the reports of the international jury, and I amn indebted for many of the figulres here given, supplementary to my own notes at the Exposition, to the report of M. Gernaert.* The tools consist of enormnous trepans, one of which weighed no less than 14,000 kilogrammes, about 15 tons, so large and ponderous that it was hardly possible to conceive of its being suspended in a shaft, and made to rise and fall upon the rocks at the bottom. The general construction of the trepans will be understood from the annexed figL ures. The massive framewnork is armed at the bottom with stout chisel-like teeth of steel, securely attached in conical sockets, and, in the most approved forms of the apparatus, bolted in, or so strongly keyed that they cannot be loosened and lost out in the Massive Treit during, the violent ssive Trepals. shocks of working. The annexed figure shows the form of a full-blade trepan, (ct lame pleine,) as used by Messrs. Dru Brothers, successors to Messrs. Mulot, in boring at the Butte-auxCailles. One of the preceding figures shows the construction of a trepal with a guide rod at the bottom, as used by M. -: ind, for enlarging holes already bored by a smaller tool. This form is imade with - a detaching apparatus at the top, (not shown in the figure,) so that it can be raised and. dropped in the hole. It cuts by the percussive force of the blow. The notable example of boring large shafts by the method indicated, was, as already mentioned, the construction of two shafts in the department of the Moselle, France, at L'Hopital, for the St. Avold Company. Two borings were made; one for an air-shaft (No. 1) with a diameter of 1lm.80 within the tubbing, and 2m.56 in- its greatest diameter; the other (or No. 2) forz a, windhillg or hoisting shaft was bored with a diameter of 4m.10, and was 3m.40 when finished. The operations, according to this methodl,'succeed in the following Dru's Trepan. order: lReport of M. Gernaert in the jury reports. BORING LARGE MINING SHAFTS. 71 1. Construction upon the surface-buildings and dlerricks, 2. Boring the pits. 3. Lowering the tubbing. 4. Puddling or packing. 5. Packing at the base of the tubbing. 1. Su'lface preparations. -The preliminary operations consisted in the construction of the necessary buildings for the engines and tools, and the erection of a derrick over the site of the pit. All these were of temporary construction, intended to be used merely during the progress of the work. The derrick was made of four suypports strongly framled together, and sustaining a platform about thirty feet above the surface of the ground. Upon this a railway or tram-road was laid for the trucks, which carried the boring tools and rods. The engines for sinking comprised the cuapstacn, the jumper, and the donlcey-engine. The capstan was used for lowering and hoisting the boring tools in the pits, and for lowering the tubbing or lining of the shaft. The engines had a nollninal force of 25 horse-power. The diameter of the cylinder was 0m.56, and the length of the stroke 0m1.70. The respective diameters of the gearing were 1m.70 and. Om.35. Admitting an effective pressure of three atmospheres, the initial force upon the driving shaft was 48,513 kilogranimes. The first rope used at the air-shaft had a section of 54 square centimnetres, capable of sustaining a stinain of 5,400 kilogrammlles. It was made of good hemp; but after working for one year, it broke in lifting a trepan weighing 3,858 kilogramumues. The tool fell from a height of 86 metres, taking with it 17 metres of the rope. This accident occasioned a stoppage of nine days. The cable was replaced by another having a section of 85 square centimetres, and after using it for fourteen months the work was suspended for three days in order to make a new splice. The second machine-the jumper-was made of an engine cylinder, open at the bottom and closed at the top. The piston-rod was connected directly with the wooden beam, carrying the tool for cutting and boring at its other end. By the alternate lifting and falling of this tool -with the attached beam, the rock was cut arway. The diameter of the piston of the jumper was Om.60, and the greatest length of stroke was one metre. The jumnper dlid not require any repairs during the whole operation of sinking the shaft. The third machine —the donkey-engine —was used to work a pump for hot and for cold water. It is indispensable for the supply of the boiler, as the capstan and the jumper work irregularly. Experience has shown that the feed-paumps should be in duplicate, so as to avoid the necessity of stopping for repairs. The preparations for sinking the air-shaft were commenced in October, 1862, and were finished in the following month of April. The expense was as follows: Francs. Buildings.............. 28, 302. 65 Machines and tools........................... 37, 326. 91 Total-.... 65................. 6, G29. 56 Boring the pits.-Before commencing the sinking with the special tools, a preparatory pit was sunk to a depth of 21m.40, and WVas lined with masonry to a diameter of 2m.80 up to within 5 metres of the sur 72 MECHANICAL APPLIANCES OF MINING. face, where the diameter was increased to 4 metres. This shoulder in the stone lining afforded a foundation for a platform. The sinking was accomplished by two different operations. First, a central pit of lm.37 was sunk and then enlarged to 2m.26. The debris of this enlargement fell into the first pit. The tubbing was inserted in the enlarged pit. The boring tools employed in these operations will now be described: the scraper, the scrape-hook, and other apparatus was used indiscriminately inl the two pits. The little trepan first employed weighed 2,085 kilogrammes, and was formed of two principal parts-the fork and the blade. The blade was lm.26 long, and had teeth of cast-steel, or of iron faced with steel. These teeth increased the diameter of the trepan to 1m.37. The blade was joined by means of keys to two strong iron arms, which were united above with a central shaft, which was connected by a slide with the suspension apparatus. This trepan worked easily through the sandstone of the Vosges —f/res des Vosges. The fall given was Om.30. The progress per day was at first Om.79, and it diminished to 0n.52, and then to 0m.28 at a depth of 121 metres; but at 135 mletres in depth, in a stratuml of strongly aggregated silicious red sandstone, the progress was only 0111.15 and 0m.11. It was soon found that this trepan was too light to stand the shocks of the blows, and three successive ruptures of the stemn made it necessary to procure a stronger trepan, weighing 3,858 kilogrammnes, divided among the various parts, as follows: Kilos. Body of trepan...................................... 2, 700 Guide................................................... 340 Blade........................... 230 Four teeth of the head. —........-............-. - - 148 Four intermediate teeth............-.................... 88 Plates and keys-3.......................-.................... 352 Total weight................................. 3, 858 The teeth are fixed upon this mass of iron by means of keys. The sockets for the reception of the tenons are conical, and are 0'm.10 in diamneter at the base and 01.09 at the top. The progress in the work made by this trepan, fiom the commencement, was from 0m.28 to 0m.32, and even as high as om.83, giving a mean of 01'.39, being three times as munch as made by the first trepan. This shows clearly that the heavy trepans are best for the hard strata. The trepan whichl was first, used for the enlargement of the pit to the diameter of 2111.56 had a blade 2111.46 in length; it was formed like the little trepan first used, and had a blade fixed upon a fork, and weighed in all 3,980 kilogramnles, divided as follows: Kilos. Fork................. 2, 500 Blade.-................................... 906 Six teeth of the head -......................... O........... 102 Three intermediate teeth.. —................. —.-.......- 48 Two plates.....-................................. 430 Total weight......................................... 3, 980 BORING LARGE MINING SHAFTS. 73 In order to avoid the frequent breaking out of the teeth, this trepau was lifted only m011.20. The progress imade with it daily was from 1n.110 to 0'.18 at the last, when a stratum of hard sandstone was encountered and the weight of the trepan was found to be insufficient. Two blades, one above the other, were then united to the fork by rings and bolts. Each of these blades carriod the teeth so as to cut the strata in two steps. This new tool weighed about 5,000 kilogranimes. It worked four months, and required frequent re-pairs. The rate of progress per day was only 0111.11. It was then decided to replace this trepan by a more massive one, weighing 8,000 kilogrammles, and 2111.50 in diameter. With this the progress was increased to 0111.34 a day, thus showing a second time that in hard rock heavy trepans are required. The diamneter of the pit at the beginning was 211m.56; at 134m depth it was reduced to 2111.45; at 155m depth itwas reduced to 2111.40; from 155"1.00 to 1551".50 depth it was reduced to 2111.33; from 155111.50 to 1581'.00 depth it was reduced to 21.25. At this depth the little pit was continued for a depth of seven metres, and a circnlar curb of 01.40 was fixed to receive the base of the tubbing. The work of sinking this air-shaft lasted about twenty-eight months and a half. The central pit required 392 dlays, including 46 days during which work was stopped, so that only 346 of actual work were necessary. The enlarging operations to a diameter of 211'.56 occupied 469 days, including 14-8 days of no work. The depth of the central pit being 143'1.70, (equal to 471.46 feet,) the mean progress for each working day was 4111.15, (13 feet,) and the enlarging to 2m.40 gave a daily mlean of 4m.25 for a depth of 13611160. The expenses of boring were as follows: Francs, Salaries and wageas.....-...-....55........-..... 55, 039. 81 Fuel.-.-........................................ 12, 513. 11 Oil and grease.-......................-......... 2, 381. 71 Rlopes..... 98........... -............... 2 20 Iron steel, and repairs to tools........................ —... 12, 530. 90 Cartage and sundries 5............................i 60. 66 Total..... e............. -- 93, 013. 39 TUBi3ING.-Before entering upon a description of the operation of tubbing the air-shaft, it w-\ill be best to explain the system adopted by Messrs. Kind and Chauldron. The tubbing of the pits is accomplished by lowering into them a metallic cylinder, which finally rests upon a proper seat or foundation, carefully cut for it at the bottom. This cylinder is made smaller than the bore of the pits, and the space between the cylinder and the walls is afterward puddled or filled in with concrete, so as to make a solid continuous lining. The mnetallic cylinder or tubbing is formed in sections of a cylinder, made of cast iron, and provided with flanges projecting inward, by which they are securely bolted together. One section or length is added after another to the top as the whole descends in the pit, so that at the completion of the work the whole pit is lined with iron from the top to the bottom. The outer surface of all these sections of the cylinder is quite smooth; but in the inside, besides the flanges for the bolts, there are horizontal ribs or -webs cast with each segment, and intended to strengthen them. The thickness of the tubbing will evidently vary with the diamneter of 74 MECHANICAL APPLIANCES OF MINING. the pits and that of the different segments, according to their position in the pit. Messrs. Kind and Chaudron determine the thickness by the following formula: RxP E O- 0m.02 x 500 E represents the thickness of the tub, R the radius, and P the pressLre expressed in kilogrammes upon the square. M. Gernaert, of the International Jury of the Paris Exposition, says that the principal merit of the success at LI'Hopital should be given to the inventors of the method of lining the shafts while full of water. Tihe jury awarded the highest order of prizes under the title of co-operators to the engineer, M. Kind, of the kingdom of Saxony, and to A1. Chaudron, of the mining corps of Belgium, particularly for the iimprovements in lining or tubbing, which form an indispensable complement to the process of boring shafts in watery strata, and without which the perforations, however large, would not have any great practical value. The operation of boring was not new. Many engineers had succeeded in. excavating shafts of large diameter in this manner, but the great difficulty was to secure a firm and water-tight lining for them. MT. Kind had proposed to lower tubbings made of wooden staves held by metal hoops. Many shafts were lined in this way, but all or nearly all were:failures. A shaft was finished in this manner at Dalbuch, in West1< phalia; but when the wal-.... x)b I \ e ter was pumped out, lown 6 b~ h b h _-= to a certain level the pressure displaced the staves and it became necessary to insert very heavy iron rings throughout the _ whole extent of the tubbing. But notwithstand-. ing these expensive efforts < k - -the quantity of water N + G % / v which forced its way through the vertical joints was sufficient to supply a /_____________ " 6 - -- -powerful pump. Cast-iron tubbing made in segments of a cylinder and bolted together was o};/ Ilbt; llm >16 next employed; but even these notwithstanding the,1 great care used in fitting and placing themg allowed T, water to penetrate, especially along the vrertical joints. But at L'll6pital, 1[~ M. Chaudron avoided' these difficulties by casting sections of the cylintdrical tubbing in one piece. These sections were made about Im.50 high and 3m.40 Cylinder and Moss Box. in diameter and varied in thickness from Om. 060 to Om.028, but were strengthened by ribs and flanges on the inside, which served also for bolting one section to another. BORING LARGE MIINING SHAFTS. 75 The opposing faces of these cylindrical sections were truly turned or planed down at right angles with the axis, so that they fitted accurately one upon another. The joint was made more perfect and tight by a packing of heavy sheet lead. The shaft having been bored to the proper depth through the watery ground, and a firm seat or socket secured at the bottom in solid and comparatively impermeable rock, the next operation was to lower the cast-iron tubbing to its place. This was accomplished in the most ingenious manner by AI. Chaudron, by tightly closing the bottoml segrment of the cylinder with a hemispherical cap, so secured that it could be afterward removed, and then floating the cylinder in the water of the pit. But in order to secure the desceut as section after section was added at the top a central open column or tube e e was bolted to the bottom, and through this, by means of holes drilled at proper distances, water was allowed to enter the inside of the cylinder for the purpose of sinking it, and to aid in keeping it in a vertical position. The annexed woodcut shows, in section, the cylinder, the convex bottom, the cenltral or equilibrium column, the moss-box, and the suspending rods b b and b' b'. The moss-box is a contrivance similarin its objects and application to the seed-bag used by the borers of petroleum wells to cut off the ingress of water froim strata around the pipe. By means of the imoss, expanded laterally whenl the cylindrical column of cast-iron tubbing is allowed to rest upon it, a tight joint is formed between the firm rock at the bottom and the cast-iron tubbing, thus effectually shutting out the water. The entire cost of sinking the first shaft (or shaft No. 1) at L'HlOpital through the watery strata to a depth of 140 metres, the internal diamter being 11m.80, amounted to 255,041.27 francs, divided thus: Francs. Preliminary works....................-................ 65,629.56 Sinking the pit.... o.. 93,013.39 Tubbing.................................... 78,577.53 Concreting -11...............811.2.0 Packing............. -............................ 6,009.59 Total.... — 255,041.27 Which gives an expense of 1,600 francs per running hmetre. The cost of shaft No. 2 is estimated as follows: Francs. Preliminary workls......... -..... -. -........... 104,571.77 Boring the shaft-......-..-...-......... 141,659.31 Piping- -...................-................... 169,220.07 Concreting................... —-cp........... wu.... 15,00,000 Packing.............. I............................. 10,000.00 Total.........................440,451.15 or at the rate of 3,100 francs per running metre. The preliminary workl commenced in September, 1863, and on the 6th of April the concreting was finishedl; the work lasted three years and a half 76 MECHANICAL APPLIANCES OF MINING. CHAPTER VII. MACHINES FO R CUTTING OUT COAL. Before proceeding to throw down coal from its place in the bed it. is necessary to undercut it, that is, to excavate a space at the floor of the seam, partly in the floor and partly in the coal, thus underinining the coal so that its gravity assists in bringing it down. This undercutting operation is known as holing, baring, kirving or undercutting, and is one of the imost laborious and difficult duties which the miner is called upon to perform. It; is often effected under the greatest disadvantages, especially when the seam of coal is very thin, and is cut on the end, to imlprove its salable qualities. The work is usually accomplished by means of a pick in the hands of a mniner, while he rests extended upon his side. An experienced miner makes about forty blows a minute with a pick and cuts from three to four feet under the coal, at the rate of one to one andcl. a half linear yards per hour. In order that the miner may have t he necessary space for his body in morking so far under the coal,,much of the coal has to be cut away and destroyed..It is estimated that the miner under sueh circumstances exerts about one-sixth of a horse-power, which is applied percussively. He works into the coal as a mechanic with a hammer and. cold-chisel used to cut away iron before planing and slotting machines were invented. The proposition to substitute machines for manual labor in cutting out coal was made some twenty years ago, by Mr. Peace, of W~igan. He invented a machine called the iron-mlan, but it met with ridicule and contempt. Much attention has of late been given to the construction of machines for the purpose alnd a very considerable degree of success has been attained; but it cannot be said that any of the machines yet put into operation give entire satisfaction under all conditions. Most of the efforts in this direction have been made in England, where several machines have been brought prominently before the public by means of descriptions and advertising, and by the exhibition of the machines or models at the Paris Exposition of 1867. The following observations upon the value and importance of mlachines for excavating coal are taken from the Colliery Guardian, November, 1869: s How to win andl work coal most, economically, is a problem the satisfactory solution of which is of the highest moment to the colliery owner, the mining engineer, and the publlic at large. In this matter producers and consumers are alike interested, and the question is one the growing importance of which is becoming daily more evident. In these times of keen competition, the most successful man in any branch of industry'will generally be the one who has at his command the most efficient appliances in the way of improved machinery andcl skillful modes of operation. To this rule-applicable to trade and manufacture generally-coal-mining is no exception. A saving of a very insignificant admounit-say but a few farthinigs-per ton, upon the whole of the out-put of a large colliery, will make a marvelous difference in tIle financial prosperity of the concern, and will present a very satisfactory result in the profit and loss account. To this fact colliery owners and managers are fully alive. Hence, in the meetings of the North of England Institute of Miningr Engineers, and other kindred associations established in the several miningr districts of Great Britain, attention is perpetually directed to this one point, and a patient and painstaking examination is given to every proposal, the professed object of which is to facilitate any of the numerous operations connected with mining industry. Any improvement in boring or sinking-in coalgetting or nnderground conveyance-in winding or shipping the produce of the mine, need only be fairly brought under the notice of the mining community to insure for it careful consideration and impartial judgment. Special attention has of late years been directed to the subject of coal-getting by machinery. More than a century has elapsed since the first apparatus designed for the effecting this object was patented, and since that time " iron men" and coal-getters in great numbers, and almost equally COAL-CUTTING MACHINES. 7 7 great variety, have been presented to the mining public. Additional impetus was given to inventive genius by the appointment of a committee of the North of Ellgland Institute. commissioned to investigate the sublject, and to report upon the value of existing patents; by the prizes offered by the South Lancashire and Cheshire Coal Association for the best coal-cutting machine; and by the encouragemen:t afforded by mining engineers, both in their individual capacity and when incorporated into associations. It was felt that, looking at the success which in other departments of industry has attended the substitution of machinery for hand labor, there was good ground for the belief that machinery mlight also be advantageously applied to the cutting of so uniform a substance as coal, and the driving of airways throLgh it. The purely mechanical operation of cutting, by means of a light pick, a groove of from 2~ feet to 4 feet deep along the face of coal which is to be removed, is not only slow and laborious, but also wasteful, inasmuch as a considerable amount of the seaml is necessarily cut into slack; and forming, as this process does, the chief item of expense in the excavation of coal, it has of late been more seriously forced upon the attention of coal owners by the irregularities and strikes of the workmen, which have so often brought the operations of coal mines to a ruinous stand-still. The introduction of efficient machinery is also calculated to have an important bearing on the safety of mines, enabling them to be more rapidly opened out, and the seam to be intersected or the winning to be surrounded by air-ways so as to drain off the dangerous gases. It is not to be wondered at, therefore, either that an efficient machine for getting coal should'have become an acknowledged want, or that so many ingenious inventors should have applied themselves to the production of apparatus to meet that want. It is true that many of the inventions have been crude, and some of them designed without much regard to some of the first requisites to extended application, but others have been tested in actual working, and found to give satisfactory results. Machines for coal-cutting may be classed under two distinct types, being, like the machines for rock-drilling, made upon two very different principles. One type is percussive, and imitates the cutting operation of the pick as swung by the miner; the other concent rates and applies the power continuously through cutters which are pressed against the coal and shave it off little by, little. Prominent among the machines of the second type is that of Carret, Marshall & Co., of Leeds, England. CARRET, MARSHALL & COMPANY'S COAL-CUTTING MACHINE. This machine works like at hand-plane; and it is claimed that it has the power of eighteen men, that it can work effectively in a space only two feet high, and cut into coal as a scoop cuts into cheese, accomplishing more in one minute than 700 blows from a pick can in the same tinme. It is about two feet high, weighs one ton, has four legs of adjustable length, and is provided with a holding piece adjusted so as to touch the roof of the drift and hold the machine firmly to its work. The motor is water, under a pressure of about 20 atmospheres or 300 pounds, and supplied through a 2-inchl pipe at the rate of 30 gallons per minute. This water pressure acts vertically on a 5-inch piston pressing against the roof, and horizontally on one about the same size, reciprocating 18 inches and 15 to 20 times in a minute. There is a pressure of 5,000 pounds against roof, and the same pressure acting horizontally, forcing three steel cutters shaped like cheese scoops into the coal. These cutting tools are 3 inches wide, and penetrate 4 feet, with a power equal to 3 horses or 18 men; and this is effected by a consumption of 50 pounds of coal per hour to feed the boiler of the engine, which makes the water pressure, and pumps the same over and over again. The construction in detail is shown by the figures,* which embrace a front elevation, a ground plan, and an end view, all drawn to a scale of three quarters of one inch to one foot, or one-sixteenth the real size. The machine in operation fixes itself dead fast upon the rails during the cutting stroke, and releases itself at the back or return stroke,, and traverses forward the requisite amount for the next cut without any. Supplied for this report by Messrs. Carrett, Marshall & Co., the manufacturers. 78 MECHANICAL APPLIANCES OF MI'NING. manual labor. Should the tools be prevented malking the full stroke at one cut, they will continue to make mlore strokes at the same place, until the miaximuml depth is attained, wrhen, the machine will mnove itself forward the required,,'ezg amoulnt for the next cut.,@,. alThus, at one opaeation, a NA/: uniiform straight depth is? /i~ ~' ~ a attained, parallel with the railsn iducing an even fracture when the coals are rought down,and _____ / therby a straight lhie for _ the new coal fiace. There'11 ~': is no percussive acti.oni' " 1! 4 geither ag~ainst the roof or / I'' i''~ f into the coal, but simply iI ___ __'~ ~ a concentrated pressure, /I,, i: producing a steady recip-'~1~ __~~!,, rocating motion at fifteen 4 strokes per minute. There __:____ 1t; l zF,'!~ 4I is, consequently, no dust t.1i ~ ~ ~ ~ ~ ~ ~ i~, F or noise, and little wear i.1 ~,.......andtear uFor tthe sania. reason, _____";;~ g whdllen cutting pyrites, the tools thro W out no 8spta rks, IQfr and the -workman al canl h. [ear /XXII~~~ 2 tul. o-any movemenit in tlIe coal t t ~,'- ~ ~ The required height I7~~ i.w alpfrom the line of rails in /i o mt or " baring," varies in 1O I' -iff e'Sisrent uiillnlles it'fllows ___ck a I 5~~ that the bydraulic cutting:'~7._... cylinder, and its direct EL~f —: action cutting tools, have required,_ /1en e lsomletime es to be rratllged AAAM _ above the carriage, aBnd -;~~_;~a ~.. asometiDmes benteath the Cmain carriage, or close d cl own upon the rails, as is illustrated in the elevations. Thefirst figure is the main carriage, with four wheels flr enough. apart to allow the ma,chine to be placed longitudinally when being transported from place to place. The screws YY are for raising and lowering the carriage and its cylinder and cutting tools. The pinion Z and the segmental rack H regulate the desired angle of the tools cutting' into the coal face, and the two nuts xx at each end of carriage regulate the aJngle required, when necessary that it shall not be in the same plane as the rails. XAA are the cutting tools, B the cutter bar, N a guide roller for the same; D is the main cylinder, with its self-acting hydraulic valve iano PAGE 78 A 8~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~mm~- -.,./ / 11 d~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /'1 * Fol ~ ~ ~ ~ ~ ~ L I m I,, 2. / 1 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~iII iII'I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~, 9 / I A I T MARSHALL". CO. is COALA, / /. ____ - - I____ _ ~r,~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~, 0k~~~k ~~~8~~~~~~1 1)11~ ~,,;. ~,,, - _ _ __ IA/LIh~g'Sf'r CARl I MARSH \LL& Co S COAL CUTTER-PLAN 1' I /,">2..,, rI ~ — ~. )"~-,,'!. \\\\\\'~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~C- -"' (*~ ~ ~ ~ Z~~~~~~~~~~~<, ~ C:'"~~~~~~~~ CARRETT, ~[ARSHAL~L &; CO~~-_LI.'S II~ICOA UTER-PRN COAL-CUTTING MACHINES. 79 tion, which passes a portion of its water alternately above and below the piston of the holder-on, which thus rises aiid falls without percussion, and follows the uneven line of the roof of ( ~// the mine, so that the rerequired stability is oivT en to the machine for the time being, an instant before the cutters enter the coal. The " holder-on piece" can be any length neces- sary to bridge over gaps in the roof; it is loose on the pin F and droops at its leading end to enable it to ride over the vary- ing projections in roof. The traverse motion is actuatedl by the pin b, ~ which connects the cut- ter bar with piston rod. and at the termination of ai each end of its stroke actuates the lever d in / both directions, which operates on the pawl e, which causes the chain? pully to revolve on the / chain i, made fast ahead? by an anchor-prop be-' tween floor and roof. Although the length c of stroke of each cntting 9. tool is eigbteen inches the practical cutting. len:gth. is sixteen inches ~ and, consequently, the' " - --- three cutters jointly give a total effective depth of four feet at each strolike of the machine finish- i ing th'e work as it goes along. The mechanism employed consists of a hydraunlic reciprocating engine, adjustable to any height and angle, havilng g a self-acting valve ino. tion. The cylinder is i four and a half inches diameter, and lined with brass, and the piston made tight with ordinary hydraulic leathers, whicb can easily be renewed. Within the piston rod is attached the cutter-bar of steel, carrying the tools or cutters. These 80 MECHANICAL APPLIANCES OF MINING. can be varied in number to suit the depth to be holed at one operation. The cutting tools are of double sheer steel, can be easily Fmade, and are very strong, and can be removed and replaced in a few moments; -they can be readily sharpened on an ordinary grindstone. The cutter-bar is also nmoveable, when transporting the machine fronm place to place, for which purpose the main cylinder is, for the tiume being, placed longitudinally with the rails. (See dotted lines in Fig. 1.) The machine is about three horse-power, and weighs one ton, and will work either right or left. (See dotted lines on ground plan.) It is selfacting in all movements, and will ascend steep gradients; being simple in all its parts, it is not liable to get out of order, and is easily managed by an ordinary miner, and can be transported from place to place, on the ordinary rails, about the mine, The machine undercuts "holes," or okirvTes," with a man and boy as attendants, and completes the work with once going over, at the rate of fifteen yards per hour, and at any angle and height from floor rails, being suitable for either "dip" or "rise"7 workings, and is capable of cutting the thinnest seams. The pressure of water which actuates this apparatus can be obtained either from the stand pipes in the pits, or from pumlps attached to any existing engine, or from a~n engine and pu-mps specially made for the purpose. The quantity necessary is only what is sufficient to fill the circuit of the pipes, using it over again when desirable, aas in the Bramah press. Each machine uses thirty gallons- per minute, at about 300 pounds pressure, according to the hardness of the coal or mineral to be operated -upon. In cutting the shale of the Cleveland ironstone bandl, a somewhat greater pressure is found to be necessary. There is no limit to the pressure of water that may be used, nor the distance it may be forced without loss of power, beyond that due to its friction along the pipes. The same water pressure is also applicable to work pumps and rotary engines for hauling, &c., and other requirements in the mine, at a distance from the engine power. In cases where there is a fall of water, say of 100 pounds pressure, it can be "intensified"1' by a self-acting machine to 400 pounds pressure, to work the coal-cutter, but sacrificing three-fourths of its bulk, which is set free. In arranging the engine and pumps required to make a " continuous stream"n' of water pressure for working these machines, it is preferable to have two steam cylinders, so that there be no dead center. They are constructed to work one, two, or four machines. Pipes, if for one machine, are of 2-inch bore, wrought iron, a superior quality of gas pipes strong enough to stand 500 pounds pressure, and are supplied at 3s. 6d. per yard. These pipes are screwed together in the ordinary manner, and adapt themselves readily to the irregularities of the floor of the mine. A flexible pipe 11-inch bore, suitable for the same pressure, allows the machine to traverse. The cost of each self-acting coal-cutting machine as here described, without its anchor-prop, traverse chain, or pipes, is ~125. This self-acting, hydraulic`, coal-CUttinlg machine, or "' iron man," which has now been two years at work, does not dispense with the labor of the miner, but performs for him the nundercutting, which is a most laborious operation, either in the end or face of coal, and in. a more efficient and economic manner than he can do it himself. The coal so operated on by the machine does not fall forward when becoming detached from the roof; but settles oni the lower bed, thereby avoiding serious accidents. It is claimed that the saving in coal alone more than pays for the outlay; COAL-CUTTINGx MACHINES. 81 and that it is practicable to cut with the most perfect ease into the floor of the line, thus preventillg all w-aste of coal whatever. The size of the coal is improved, the amount of slack is considerably reduced, and a single sea.m, it is said, will yield more by one thousand tons of coal per acre than when worked by hand labor in the usual manlllner. COAL-CUTTING MIACHINE OF iMESSRS. JONES AND LEVICOi. This machine imay be described as a contrivance. for holding and(l swinging a miner's pick so as to unidercut a coal-seaml nearly as it is lolne by hand. It is actuLated by compressed air, and is mlouanted oil a. carriage or truck with four lwheels, with an exteilded cast-iron platforiu in the rear for the man who works the machine. A crank-piin on, lywheel actuates two bevel-wheels for moving the machline back or iorward on the rails of the gallery. The handling of this machine is very simple. The workmanlln on the platform turns a wheel so as to bring-the pick into the prol)er direction; he then opens a cock,adlmitting compressedl air into the cylinder by workinig the slide with a lever. The mlacline beinii thus set in motion, it is merely requisite to move it forward to follow -up tphe work done by the pick. The air, on leaving the cylinder, escapes freely into the gallery. We subjoin the reported results of experiments made by this machine in two mines in England: In the High lRoyd colliery, in a, hard coal, and in a gfallerv in which the rails were inl a' bad state; withll'al air prelssure of folorno 2 to atmospheres and 70 to 80 blows per minute, the avera-ge hour's work of the machine was a channel froil 8mS.'20 to 9ll.15 long and fiiom 0 ".9() to 11lm.00 deep, including stoplpages. The width at the bottom wacs 0(),.03 7 and on the face OmO.0$. During 10 hlotrs' consecutive work the work produced by this mabcine was elqual to that of 20 minlers during the same time; and it appears that the consumption of air is equal to about 3 horse-power. FIIRTHS PATENT COAL-CUTTIN.G IMACHIINE. This is also a percussive machilne, aind is worked by conmpressed air. It is mounted upon wheels,Which 1run upon r'ails on the floor of the mine. A pick is attached at the forward end of the machine to the lower end of a -vertical shaft, anld a horizonta.l swing or sweep is givetl. to it by means of arms and levers connected with the piston-rod. In its formn and mode of operation, this machine solmewhat resembles the preceding. Some inmprovements in this Mlchine have been reported( recently. It is stated to be worlki-lg in the seaml known as the;" Little Coa.l," which is 2 feet 8 inches thick, and to ha've under cut a face of 500 yards in leongth to a depthl of 3 feet, using a new form of theo pick which removes thie 6dirt as it proceeds. Mir. Firth has also recently invented a method of fitting picks xWith movable cuttingt points. It is tIle general custom: to work picks with points solid; that is, the point and pickl in one piece. By this arrang-emuent it becomes necessaltry to take the whole pick out of the pit whenever blllted, in order that it nmay be sharpened. The ilip)rove1ellt consists in nmaking' a boss on that part of the pick nearest, the point. In this boss is a socket of any suitable shape, by preference a circuiar taper socklet, the loose point beig cottered into the socket against a piece of 6 82 MECHANICAL APPLIANCES OF MINING. India-rubber, or other suitable substance, at the bottom of the socket or around the outer edge of the socket, so that when the blow is given soime part of the strain is taken off the point. The edge of the socket is brought as close as possible to tile point, for as the socket must enter tihe groove made in the coal, and must be clear of the top a.nd bottom of the groove, and as in some cases the groove is not more than one and three-quarter inches in height, it will be readily seen that the closer the socket is to the point the greater the resisting strength of the point. HIURD'S COAL-CUTTING MACHINE. Mr. F. Hurd, of Rochdale, England, has invented another formn of coalcutting nmachine, in which a number of steel cutters or teeth are placed on an endless chain or band moving longitudinally arouncl a long arm. The invention is claimned to consist- in cutting horizontal, longitudinal, ralial, ancd diagonal grooves in the coal or other mineral to be excavated, by imeans of a series of link stocks containing the cutters, which are jointed together in such a mlanner that no rivets or connecting pins are required. This series of cutters passes round a pulley mounted in a radical arm, and around a toothed wheel fixed to a shaft which fits in a telescope framne to increase or reduce its length; tile radial arnm is provided with grooves which support the back of the cutter stocks, and prevent theml from being dra wn out of the groove in the radial arm. The toothed wheel may be driven to give motion to -the cutters by an improved motive-power engine, or it may be driven in any other convenient manner. The position of the radial arm is chlanged so as to give the required cut by a w-ormn hxed to the outer shell of the telescope shaft, and a caul fixed to the d(ivinlg wheel; this cal, by a lever and catch, turns the wormI at intervals, al d thus a(ldvances the cttters to the extent required. The engine consists of an oscillating cylinder to wlich the compressed air or other elastic fluid is admitted, and ifron which it is exhausted through two or more ports, tile oscillation of.tle cylinder causing the ports to be opened anzd close(l at the proper times without the aid of eccentrics or valves for giving the requisite to-and-fro motion to the piston and piston rod, which latter is connected to the crank pin inl the fly-wheel. The engine can be reversed by two double taps placed in the passages leading to and fromn the ports, -which taps are connected and worked simultaneously by levers or gearing. The cutting apparatus, aind the engine by which it is drivenD, are connected to a bracket which fits on a screwed l)illar, and it is raised or lowered by gearing connIected to the engine, and which gearing reverses the direction of motion up or down by changing the position of the wheels. The bracket also supports two shafts with two eccentrics for acting on surface clips, one to secure the bracket in the lposition requiredl, and the other to secure the radial arm. An_ apparatus for colmpressing air is' also included in the invention. It consists of a series of pump barrels, the pistons of which are worked by a diagonal disk or other equiv alent; this disk, or its equivalent, is driven by steaml or other power, and the pump barrels are all united to the air receiver. As the pressure increases in the receiver, the piston rods are disconnected in succession fi'om the elriving disk, or its equivalent, until the final coinpressioni is obtained by the last pump barrel. The pumping apparatus is placed in a water course to keep the barrels cool. An idea of the form and operation of the cutting machine may be ob- *Described with dranings complete in the Colliery Guardian, November 19, 1869. COAL-CUTTING MACHINES. 83 tained fronl the annexed figures, showing a machine designed for working in very narrow seams. The first is a plan, and shows the principal Hurd's Coal-cutting inaclhine. part of the fraine jj of the machine with its long arm e4 reaching forward and carying the cutters e e, by which the groove is cut in the coal. Steam or compressed air is admitted through the pipe w to the cylinder b, in which a piston moves back and forth and gives motion to the fly-wheel c. The arm is controlled by a tangent screw working in a segmlent.of a wheel, the Outlines of which are shown between i and i'. By means of this screw, moved by a crank at the side of the cylinder b, the arm can be thrown to one side or the other. It has a horizontal sweep of three feet or more, carrying the cutters with it, as shown in the figure, each tooth in succession cutting or scraping off a little of the coal. Alternate teeth are different, one cutting a double groove and leaving a little ridge or tongue which the next tooth cuts away. The cutter stocks, into which the cutters e e are set and held by a screw, are linked together in a peculiar manner without rivets or pins, as indicated in the figure, which shows only two of the teeth in the sockets. One socket, by means of the hook-like or curvedl connections, holds to the next, anld thus formn a chain which slides in the groove of the arm. The figure also shows a portion of one /......'', side of the end of the arm, holding the pul l. /. ley upon which the chain of cutters turns.: -'By means of a screw and lock-nut this pulley may be thrown outward to take up the slack of the chain. This apparatus is reported to be working in a 20-inch seam, and alking a semi-circular sweep'of 6 feet 6 inches in four minutes, with only 25 pounds pressure on a 6-inch cylinder with six inches stroke, cutting a groove of 1I inch. The weight of the machine is nearly four hundred pounds. Mr. Hurd has also made a machine to be worked by hand, which is much lighter. BREAKING DOWVN COAL BY HYDRAULIC PRESSURE. As it is exceedingly difficult, if not impossible, to secure perfect ventilation in all parts of coal mines so as to effectually dilute the combustible gases alnd render them inexplosive, it becomes very important to dispense with the use of gunpowder, the explosion of which not only fills the workings with smoke and vitiates the air, but frequently ignites the fire-damp. It is the opinion of one of the inspectors of mnines in England that half the explosions of fire-damp are traceable to firing shots, and that a vast number of accidents from falls of roof are caused by the shattered condition of shale-roofs, after blasting to the extent, now prac 84a jMECHANICAL APPLIANCES OF MINING. ticed. In dangerous coal-seanms it is clearly wrong to use gunlpowder, acnd it is perhaps a mistake under any circumstances. The excepItiolls are thought to be rare, while the accounts of fata;l accidents are nulnerous.* WVherever much powder is used in getting down the coal, the value of the coal is much lessened. It is a well-known fact in England that the least capable men in any colliery use tle jmost powder, an.id as a consequence the coal which the;y mline is less valuable than that thrownT down with less consumption of powder, by skillful and experienced mlinrers. Again, in some cases, coal-seams themselves have been ignited by thle use of powder. All these objections to the use of powder have rendered a substitute very desirable. Mr. Samuel P. Bidder, jr., of England, proposes to use the force of a hydraulic press, and has explerimented with a machine constructed for the purpose. The machine that lie exhibited ill model at the Institution of Civil Engineers is described as follows:f The principal machine consists of a small hydraulic press, weighing about 60 lbs., a.and of 15 tonlls power. To this press is attached a, pair of steel tension straps, bent in. the form of a tuning-fork, and \\which are connected with the press by a collar. At the end of these straps is first placedl a clearance box, about 4 iclles loig, and upon each side of the stiraps expanding pieces, (also made of steel,) whiclh exert a pressure at the sides of the hole, and are 15 inches long. The points of a pair of twin Awledges, 15 inches by 3 inches, coinstituting one wedge, are tlheii inserted ill the expanding piece, aiind the iiachliine is fixsed in the liole. The lldlndraulic press, (liaviin- been already cllharged with about three pints of water, wxhich may be used over and over e again without loss,) is then worked by a iman by ineals of a small handle, anl the ram fi'om the cylinder is forced out, thus dlriviin up the pair of wedges betwxeen thle expandillg pieces, givilng a lateral extension of about 3 inches. This not beingl in all cases smufficient to bring down the coal, the press is withdrawn, anid the relief-valve opened, thllereby allowinlg tlhe water to rettril to the reservoir. A seconid wedge is thenl inserted betw ee tell two t++win wedges lby imeanls of a sn ill rlod five-eight1hs of an inch iit (li.l eter, alid, the lpress being again connlected, tlis ege is driven home in thle nlla erlbeffre described. By this meains an iadditional expalsioll of 3 inlclles is obtaiincied, inalkid a total eIxp)lsion of 6 inches, whichl in most cases is found sufficient; but a third m wedle cal be aplied, if necessary1', and the expansion t.lus increacsedC to any reasonable extenlt. In this ni I1ner as lmuch as 10 or 12 ewts. of coal have beein bronolht clovwn in ten inminiUteS. The idrillinc apparatuls, tlle principal part o:f the llachine, econsists' of a. slcrew 4 fe(3t by 1L inches in diameter, to the end of whicll is attaclhed the drill..i Tlhe fulcrumin for taking the resistance of the screiw is obtained by inserting a ba1r of' iron in tfhe coal at the side of the place selected for the hole mwm hich the Illnchiane 11as to drill. This small aperture is made by punchllirg with tlhe odi'ilary instrlmlllelt a bole 10 inches d(eep.nid 1 inlch in dialmeter, alncl the tiime occupied in making thllis pirearation is usually about four niinut-les. The small bar for talking the resist1ance of the screw is then inserted, and it iiay either be fixed at the side or in the face of the coal, as the case may require. The screw is then adjusted to this bar, andcl the drill driven in the coal by a mian tilurling the handle at the end of the screw. The tilie occupied inl drillig this hole for the mrnachine, 3 inches in diamleter and 3 feet 6 inclles deep, i firoomn 10 to 15 ilminlteis, according to the hardness of the strata,; and if it is necessary to dcill the hole in such a position that the rotary lmotion of the hlancle by whllich thle screwr is propellecl cannlot be obtained, a ratchet Illay be used, so that, under aly circulnistances, no difficulty can be felt in procuring the required motion. Another sad illustration of the carelessness of some iminers, Ilotx withstandiiing tlle knowledge they have of the perils to which theyr alre subjected in thie pursnit of their daily avocations, is furnished by a shlockinog calmlity wilhichi occurred at the Astley Deep Pit, Duklhnfield, onl Thursday evening last week, and the cause of whicih has since been ascertained. Certain parts of the pit are lknowAii to be stollongly charged with gas, and the colliery regulations very prolerly prohibited blasting in consequence. In spite of the rule, however, and wvell knowing,' as they iinmst have donle, the awful. risk to -which they wvere subjectilig both themselves and their fillox-w-orlkmen, tiwo miners fired a shot in one of the highly dlangeros "brows." They have paid the penalty of their hardilloocl alnd reclklessness by the, loss of their own lives; but alongl with them seven others have also been hurried into eternity. One of these men had been iwarned before the magistrates of the consequence of neglecting the precautions prescribed in the rules onlly a fewr mionthis go. The inquest wvas on Saturday formally opened and adjournedl.-Co11ier y Gualcrdlia, Ia rch 11 1870. t Mining Jonrnail, June 12, 1869. BREAKING DOWN COAL BY HYDRAULIC PRESSURE. 85 The first trial of the machine was made at a pit belonging to the North Staffordshire Coal and Iron Company, (Limited,) at Talke-o'-th'-Hill, in a heading in what is called the Eight-feet Banbury seanm of coal, at a depth of 359 yrrds from the surface, and under ordinary \working circumlstanuces, so far; as the place selected wras concerned. Considerable difficulty is always found in fairly testino a nmachine under such circunmstances as these, but, notwithstandcing every disadivantage, the hole for the machine was drilled and about 4 tons of coal brolught down in 25 miiniutes. Mr. Higson asked a workman in charge of the place how long it would have taken himn to have drilled the hole and fired the shot according to to the presen system of blasting, and he considered that an hour vwolld be required for the purpose, andcl a pounnl of gunllpowder -used, at a cost of 5d. The superiority of the machine was, thcerefore, evidenced by the saving of 35 minutellls in tile a. nd 5d., the cost of 0powder, ancd the work was done without the smallest danger to anyT one. Two further trials of the niachine were made in other parts of the workings. in both the Seven and Eight-feet seams, with results equally satisfactory. The mode of using the machine in the workiong of coal would be to provide each set of colliers with a pIair of steel tension straps, and the emachine could easily be carried about by a manll like a double-barrelled gun under his arm frolm place to place. It would thus be. necessary to have only one press for a, 1airgee juruber of these places; thle etire cost of th,~e mUtchinel -ry is very semll, SECTION III.- TRANSPORTATION, VENTILATION, ETC. CHAPTER VII1. TRAMWAYS AND WAGONS.'As mines increase in depth and extent, the cost of sinking and maintaining shafts is much increased, and it is no longer economically possible to keep several hoisting-shafts in operation. It is therefore necessary to confine the hoisting to one central shaft, which thus becomes the only outlet of a constantly extendling system of underground tramlwaVys, over which the minerals or debris are conveyed to the shaft in order that they may be raised to the surface. As the work of extraction of the ore or coal progresses, the distance of the mineral from the shaft, especially in collieries, is constantly increasing, being in some of the European collieries as much as 4,500 feet or more, andcl it is thus become a very imnportant item in the expense of mining to move the inineral to the shaft. So, also, when, as is comlllon in California and Nevadla, veins are reached by longy tunnels, the tramming or underground transportation fornns a serious item of the cost of getting the mineral to the surface, and it is important to determine the best forms and sizes of the wagons and tracks to be used. TRAISMMING AND TRA3M1 WAGONS IN CALIFORNIA. Very little attention has been given in the mines of the west to this subject of tram ming. The formls of wagons, or " cars," as they are usually called, are almost as numerous as the mines in which they are used. In general, they are made of wood (there are some of iron) banded with iron, and are supported upon small cast-ironwheels, runninlg upon axles of the simplest form. The size varies with the size of the tunnels, but is never larger than a main can manage with ease when loaded, except when, as at the Mount Diablo coal mines in California, horses are employed for the haulage. These coal mines perhaps present the best examples of underground tramming upon the Pacific slope. The average distance of underground hauling at these coal mines, is now perha.ps not far from one-third of a mile. This distance varies, of course, in the different mines, and in different parts of the same mine. The maximum. distance of underground haulage is in the old or u-pper Black Diamond gangway, which, friom its face to the mouth of the tunnel, is now about 4,200 feet. This tunnel is about 400 feet long, before reaching the coal, and extends for the remainder of the distance on the coal and is constantly being worked further. The haulage upon the horizontal tramnways is done by horses at an average cost of not less than fifteen cents, and probably as great as twenty cents, per ton per mile. The sizes of cars, tracks, &c., vary considerably in the different mines, but the tracks are all alike in their construction, being made by spilking a tight strap-iron rail upon wooden stringers supported on wood cross-ties. A light 1-rail would be a decided improvement. The cars at most of the 88 MECHANICAL APPLIANCES OF MINING. mines have to be made so that they cau be used not only on a, horizontal roadwcam y, b1ut also upol an ilnclinle. They are thereforle built highler belind thallin front, in ordler to prevent the coal fromu falling lback out of the full cars as they ascend the slope. At the iount Hlope slope, le'adii-ig to the loNwNest level of the Blalck Diamond m ines, and pitching at all angle of 37~ 1a5 to the south, the cars, Iuilt of wood andl sometimes of sheetiron, have the following interior dimensions: Length, 6 feet 6 inches; width, 2 feet 5 inches; depth in fionut, 2 feet 5 inches; delpth at rear end, 2 feet 11 inches. The iwxidth of tra ck is about 36 inches.. These cars hold about a, ton of coal amnd they are drawn up the slope by a stean winding engione. Soime details concerning this hoisting will be given beyond. TRAMMiING UPON THE COM3ISTOCK LODE. The annexed figure, drawn to one-twentieth of the full size shows the colstruction of a dumping car, made of wood, designed to run equally well on a horizontal track, upon a steep incline, or upon the surface. It is the form used sonlle ye. Sars since at the Ophir nm-ine, on the Conustock lode. The body of the car is supported a, little forward of its center upon the extreme end of a strong frame which i. o [>....~' turns upon a central pivot fand rests upon a1 IoAlr fr<7,nle or tluclk Dunmping Car for inclined shaft or gallery. alo franie. or trlulo carrying the low wheels. This arrangement for turniln, the car upon a p)ivot allows its load to be dumped on either side of the raised trac:l at the (lump-pile of ore, or at the attle-heap. The forward end is closed by a flap-door opening outward, suspended on an iron rod, extendinlg from one side of the car to the other. The back elnd of the car and half its length on top are closed with pla, nks, secured by strong iron strap:s. UJINDERGROUND TRAMlM3ING AB1ROAD. The next figure represents the tunlnel car used at Freiberg, Saxony. The load is sustained upon the axles by a vS0 0oE tiDmber extenduing longitiudinally in thle centers under the car. U-M@M~l1-SU 1:I -itZ l! IliltC K0 Thle wheels are of ___ ~I~ zd5 S LI good size, anl the outer endls of their axles are, zz —W1z = oO j84 0} 0supporited by the heavy iron bands depending fiom the side of the box. I, The next figmure will recall to the minds of those who have visited the Freiberg mines the; lund," or dog, so conmmnonly employed in that district. It is of wood, bound with iron, and TRANSPORTATION UNDERGROUND. 89 constructed of such a size as to be managed, when loadled, by a single man. The axles are fixed, and the car is turned, when necessary, bT tilting it so as to lift the forward axle and leave the weight resting on tle two larger wheels only. These dogs are particularly useful Gl in milles nvwhere tracks have not -' been laid. Their broad wheels ena- ----— l ble theml to go through ordinary galleries, or over the inequalities of the surface. They are gene.an however, run on Strips of boards, == ___ ______ or ways otherwise prepared, to diminish the labor of the mliers propelling them. The rapi-dly increasing production of the coml mines of Great Britain and the Continent has necessitated great impriovemelints in the Inethods of transportation underground. Tile wagons used for the p)urpose and their running gear are no longer roughly aLind rudely constructed, but are mna.de with great care. The wheels alre aicenrately malde, well bored, and fitted with carefully turned axles, and these are kept w ell lubricated by grease-boxes, so as to prevent loss of power, wear, and friction. Iii France and Blelgilum a. few years since a plain flat rail, set on edge and tightly wedged. into the cross-ties or chairs, was preferred to any other. The size of the iron depellded upon the weight to be susta.ined. For cars carrying 500 kilogramines, 0.055 by 0m).011 was sufficient; but if the track was to be used for,a long tile, heavier iron was preferred. The widt.h of track was, and is, in general, froml 0m.60 to 0lll.80. At the Blanzy collieries, where the cars carry about 1,000 ktilograumnes, (one ton,) the width is 0m.80, and the flat-bar rails measure 0ml1.07 by 011.02. At the Anzin collieries it is found advantageous to use iron cross-ties, with chairs welded or riveted to the enlds, in preference to cross-ties of wood. Rails with a rounded summit, and thicker at the base than the top, were in -use there in preference to the square-edged rail. but these have in turn given place to a light I-rail. It was calculated by Burat in 1861 that the tramways at Anzin, 0lll.60 wide, and with cross-ties of iron at distances of 0111.80, did not cost over five fanlcs per lineal mletre. But great improvements have been Inmade silce that time, and in the Supplenment an Mattriel des Houilleres, Professor Burat states that the conclusions arrived at, after very caretul investigations of the methods, are: 1. That the narrow-gauge tracks, those, for example, of 01.1150, are the most desirable. 2. That the fiat rails and bar rails o1 edlge should be abandoned for rails presenting at least two centimetres of bearing surface to the wheels..That the chllares for the cars should not be grea.eter than 400 kilogranimes, net wTeight,. in order that the attendant may easily turn the car on curves of short radius, or put it upon the track in case of' its running off. Light I-rails are in use in some of the collieries, as well as the imrethod of oiling known as IEvrard's, by mealls of an oil-box placed in a hollow axle. SELF-LUBRICATING AXLES. l]vrardl's contrivance is described in the reports upon the Paris Exposition. Itis d esig nel to supply oil in molderate and regular quantities to the journals or bearings of the wheels of wagons for -underground trammining, 90 MECHANICAL APPLIANCES OF MINING. and for excluding all grit and dirt from the bearing surfaces. The wheels are supported by journals J J, working in a hollow cylinder or box a extending across the bottom of the car. This cylinder is calibered at each end, for one-third of its length, for the reception of the journal. The middle third of the cylinder is left rough, and receives an oil-box, which may be filled through a hole in the cylinder, closed by a screw s, with a conical point, which enters the oil-box and nearly closes the hole in it, leaving only a small opening, through which oil can exude in small quantities whenever a bubble of air enters. The journals are retained in their places by caps c c, fixed to the truck and fitting over the ends of the cylinder and c-atching upon a shoulder left upon the journal. r _ -:vrard's Self-lubricating Axle. Axles of this kind used upon wagons at the mines of the Vicoigne Compalny consume a decilitre of oil in running an aggregate distance of i50 kiloinetres-about 62 miles. Oil is renewed every fortnight. MI. Evrard, in his description in detail, * states that a car with its two axles did not consume more than three decilitres of oil in 22 days' running, the total distance run having been 448 kilometres. Since the Exposition of 1867 a commission of mining engineers has been organized in Belgiuml for the purpose of studying the different forms of cars and tramways in use in the coal basins of the north of France and in Belgium. The car lesigined by M. Parent has been introducedl in many of the mines of the Anzin company, and appears to give great satisfaction. The body is rectangular, 1".10 long, 0mn.778 wide, and m0.57 deep; capacity, five hectolitres. The body is mlade of iron, two millimletres thick for the sides and four milimetres for the bottom. The total weight of the car, with wheels of wrought iron, is 190 kilogramlmes, and with cast-iron wheels, 210 kilogrammlnes. They cost 96 francs each, with cast wheels, and 102 francs with the wrought-iron wheels. These wrought wheels are stamped from a single piece of iron, are 0.28 in diameter, and weigh 8 kilogramines each. They are much lighter and less liable to break than the cast-iron wheels. At the Chazotte collieries, M. Max +rvrard has adopted the Pagat wheel and axle. This is a broad-faced wheel of small diameter, the form anld constructioni of which may be'best / f, munderstood by referenlce to the annexed figure, which is a section through the center, showing the end of the axle and the oil-box. This oill I box appears to be the chief merit of this wheel. The end of the axle protrudes w7ithin it, and the wheel is held in place by a simple spring linchpiu inserted through one of the large holes made in the hub to permit the introdcluction of the grease from time to time. These Pagat Wheel and Oil-box. two openings are closed by corks c c only. A' In Burat's Mat6riel des Houillbres-suppldmlent, 1865, pp. 12-14. TRANSPORTATION UNDERGROUND. 91 hard grease or tallow is used, and is inserted by means of an injector. When by movement of the wheel the axle warms a little, the grease slowly melts and runs into the bearing so gradually that it need not be renewved oftener than twice a week. According to M. EPvrard this box once filled with grease is sufficient for running a distance of sixteen kilometres. It holds 128 grammes; the grease costs 52 francs per 100 kilogrammes, and the expense per ton, per kilometre, is, consequently, for the four wheels of a car, O f.0455. These wheels are used under an oval tub car, the capacity of which is limited to 340 kilograminmes. At Blanzy, the cars are rectangular, expanded over the wheels; carry a charge of 600 kilogrammues and weigh 230 kilogrammlles. The wheels turn upon the axles, and the axles turn in boxes fixed to the body of the car. USE OF SMIALL TRAM-WVAGONS. In South Wales it has been argued that small tramn-wagons are more economlical than large ones, since they permit less height of the drifts,7 less cost of tralmways, and the use of ponies and boys instead of horses. At a meeting of the Institute of Engineers it was stated that at a colliery in the Aberdare Valley there had been effected, by the introduction of small trains, a saving of is. a ton. The vein was 3 feet 8 inches thickl and the old principle was to cut as much as 6 feet 6 inches for head-way and horse- road. But upon the introduction of the small trains the whole depth to be cut was 4 feet 6 inches; and, consequently, there was a saving of two feet in top or bottom —the top being a hard cliff. In getting out 150 tons a day with e large the large tram, fourteen horses were employed, at a cost of t4 12s. Sd.; with small trams, the same an-mount of horse work was done for ~1 Ils. Scd.-that was the cost of ponies, boys, and jiggermen-so that there was a saving of nearly Gd. a ton on that itelm alone. On the other hand, it was asserted that it is certainly possible to devise a large traml with a smaller tare in proportion to the load than would attend a tramn with a capacity of only six or ten hundred-weight; and further, that it is very doubtful whether a saving of one-third could be made in the cost of hauling by the use of.ponies rather than horses. The following figures were given as showing the comparative cost of working with large and small trains in the same colliery-No. 3 vein, which varied from 2 feet 6 inches to 3 feet 6 inches or 3 feet 9 inches. Tram of one Tram of ten hulnton. dclred weight. s. d. s. d. Cost of cutting coal................... 2 0 per ton. 2 0 per ton. Cutting bottom for horse height..... —. 0 3 per ton. 0 l per ton. Hauling underground..-............... 0 4 perton. 0 32 per ton. Carting coal in stalls.....0 2 per ton. nil. per tonl. Banking, screening, &c -..-.-0 -l —per ton. 0 1 per ton. Total........ -......... 2 11 2 6 Showing a saving of 5d. per ton in favor of the small tralm. But it was admitted that with a thick vein these items might be altered materially. This is a matter upon which no general rule can be established; the miner will of necessity be governed in the choice of the form and size of wagons by the peculiar local conditions of thlle colliery. 92 MECHANICAL APPLIANCES OF MINING. PORTABLE TRAMWVAYS. In coal cutting or drilling by machinery, or in any mining work where rapid advances are made, it becomes important to be able to quickly extend the tramway or track so as to keep the nachine well up to the face. To facilitate this, dMr. Firthll, of England, who has made and patented several improvements in coal-cutting machines, proposes to make the ties or sleepers in such a form that the rails can be twisted or sprung into them. His plan is described in an English journal as follows: It is -the present custom in fixing the railroad for coal-cuttinog machines, to use rails about four yards in length, having one sleeper for each joint a'id one or more interinediate sleepers for eacl pair of rails, The kind of sleeper hitherto used has been of such a formn that the interumeliate sleepers have to ble hammluered on and off' each time the roadc has to be removed nearer to the face of the coal. The improvement consists in making the intermediate sleepers of such a formn that rails can be twisted out of and into them, instead of haLummering the sleepers off andl on to the rails, which imlprovenlent tends to a great saving of labor and tinle in nmaking thle railroad for coal-cutting nmachines, andcl subsequently in takding it to pieces and putting it togetller again whenever it has to be removed. At the outer end of the sleeper is a lug under which the outer flange or edge of the foot of the rail enters, and the foot of the rail then drops below a stop on the sleeper, Awhich prevents the rail escaping laterally until its inner edge is intentionally raised. The sanme form, or a modification of the samle form, can be applied to the tramnroads of mines generally, also to sidings and railroacds of other descriptions, and by this means no wooden wedges or keys are required to keep the rails in their places. TRAMMING BY STATIONARY ENGINES. In Belgiuml the formations through which the galleries of the mines are cut are so soft, and undergo such continual change by swelling, that it is not practicable, except in rare cases, to establish a system of hauling the coal by stationary steam power such as has been successfully introduced in the English collieries. ILn most of the coal mines of England the regularity of the strata is such that a shaft may be used for a long time for the extraction of an enormous amount of coal brought to the shaft from great horizontal distances below. It is not unusual to see in Great Britain shafts from which 600, 1,000, 1,200, and even 1,500 or 1,600 tons are extracted in twenty-four hourIs. Such an amount of work, extending over great periods of time, requires all the parts of the shaft to be constructed in a solid and p)ermanent imanner. For the conveyance of such immense quantities of coal to the shafts it is necessary to use power greater than is afforded by men trundling the wagons in the usual way. The coal is loaded into wagon'; containing fromn 350 to 450 kilogramimes each, alnd five or six of these wa.gons are then formed into trains, which are drawn by horses to the mlain tramTways, which vary in length from a few hundred yards to evenl a mile. Tramways may be divided into three classes: first, those in which the slope toward the shaft is sufficient for trains to descend by their own gravity, and, in descending, to draw up the empty tyrains; secondc, those in lwhich the grade is reversed, and sufficient to permit the empty trains to descend from the shaft to the end of the road by their own gravity; third, those ili which the bled or grade is horizontal, or nearly so, necessitating power for the movement of the trains either way. n1 the second class the loaded trains are usually drawn up toward the shaft by means of a cable wound upon a druml by a steam engine, while the empty cars are lowered by a cable unwindingl from the saime drum. TRANSPORTATION UNDERGROUND. 93 In the third class an. endless rope or cable, which traverses the gallery along the track between the rails, is mnoved by an engine, and the trailns a.re couplled to this moving rope and so carried to their destination. A few details upon this third class of tra.m-roads may be desirable., It is understood,., that a double track is laid on / / the levels where this method of, moving the trains is used. The general arrangement of the Gca- N bles, the enlginie, &c., are shown *r by the figure in plan showing - hl two tracks, the engine, &e. The driving engine is gen-' \ erally placed in a recess cut at F one side of the gallery,. anlld near an air-shaft, by which the smoke froln the fulrnaces canll escape. The cable is wound upon a drum, and is supportedl - l, tllroulghout its course by hori- zontal rollers, and in the curves - is gunied ec y vertical rollers. At the ends of tlhe route tlhe | cable turns tuponl drums placed i between the tracks, the diame-ll 1 I ter of which is equal to the dis-' tarnce friom center to center of;i ) the roads. In somle cases the cables run for a piart of the distanlce undergrondll. Iin order', }' to secure a proper tension of \. the cable, it is passed over a pulley uponl a movable frame, counterpoised in such a way as to takle up the slack of the cable and give a constant tension. Trhe cable travels constantly in one direction, and'thus moves Tramming by steam- power mdlergl'round. opposite ways'upon the two traclks. Trains of twenty or thirty wagons can be mloved by this arrangement. Formerly in some mines the engine was established at the surface, a.nd the cable was guided to the bottom by pulleys and shleaves; this was the first planL adopted, bnt it occasions too mullch friction and wear of the rope, and now the engine is always placed underground. To start or stop the trains it is not necessary to stop tl)e cables. There is a conductor in the first waoon of each train. Whelle-i hIe wants to put the train in imotion he lifts up the cable with a hook, mkecs, it pass alomng a wooden block fixed unuder the wagon, and by melans of a lever he brings forward a wooden wedge, which squeezes the cable aogaillnst tile woo7den block. Cable and wagon, being then connected, move together. By maneuvering his lever the other way, the conducnetor disconnects the rope and stlops the train. Wlhen the train arrives opposite the macllipe, or where the cable runs under ground, the conductor loosens the rope and the train runs alone. The momldntul.i carries the train up to the !94 MECHANICAL APPLIANCES OF -MINING. point where the cable reappears; the conductor then again connects the rope to the train as before. In the coal mlines of Pelton tlhe principal road is 1,500 metres in len gth. It is partly horizontal and partly on a slope of five degrees. The driving cable is 0".022 in diameter, its running speed is 6m.00 per second, and it carries a train of 30 wagons; the widlth of the rail is 01'1.60; the strength of the motive power is 40 horse-power; and the cable transports 52 trains in 12 hours, representing a duty of 560 tolls of coal. Francs. The labor costs -........................................... 13.50 Coal (refuse) for fuel, 6 tons at 3 francs....................... 18.00 Repairs, interest, &c-...................76.50 Total...........................................- - --...... 108.00 W;hich represents a cost of 0.137 franc per ton per kilometre. Under the most favorable conditions transportation by horses costs 0.21 franc per ton, and by tralmmers, 0.67 franc. GRIP PULLEYS. In hauling heavy loacds up inclines in mines or elsewhere, the grip pulleys may be used with great advantage. Mr. A. S. 1Hallidie, of Sanl Francisco, has recently invented a pulley of this description, which is noticed as follows in the Scientific Press of that city: Its novelty consists in so arranging the two gripping jaws or clips, that they will be operated by the strain upon the rope, without the necessity of bolts, rivets, screws, or other device for holding them in place. The rim of the wheel is made in two parts, one of which is formed solid with an arm, and of only half the desired thickness of the riml, so that it forms a shoulder. This is then bolted or riveted to the other part, thus forming a rim of the required thickness. The flanges, between which the gripping jaws or clips are placed, are simply spread apart in the ordinary manner of forming the groove in pulleys. At intervals around the entire grooved periphery of the wheel are cavities or recesses, placed opposite one another in the two flanges. These are made widest at the lower part. The clips or jaws are made with spreading arms, so as to admit the rope easily, and the corners extend into the cavities just mentioned, thus preventing their dropping out, while alllowing of a slight motion to and from one another. A groove or space is made just below the point of meeting of the clips, so that when the strain comes on the rope or chain, which rests on the bottom of the groove between the two jaws, the central part of each clip will be depressed, thus camising the jaws to grip the rope and prevent its slipping, while the strain is on, but as soon as this is removed, the jawrs -will work freely in their sockets and allow the rope to open them, and thus free itself from the pulley. This invention, in which the jaws are operated automatically by the strain on the rope and their own weight, is exceedingly simple and effective, has no complicated parts to get out of order. or break, and is cheaper than other kinds. TRAMMING BY MINING LOCOMOTIVES. Many efforts have been made to substitute small locomotive engines for animal power in undergrounnd haulage, especially where the amount to be moved is constant and large. In some of the Pennsylvania collieries such locomotives are now successfully enmployed. The first machine of this kind wTas built for the Lehigh Coal and Navigation Company by M-1essrs. Grice & Long', of Philadelphia. It is a locomotive of peculiar construction, measuring 12 feet in length by about 4 feet 4 inches in width, and 6 feet in height from rail to top of stack or roof. It weighs 11,000 pounds, with water and fuel. The wheels are about 2 feet diameter, are four in number andcl are all drivers. Distance between the wheels, 5 feet 6 inches; gauge of track, 3 feet 6 inches; rails, 40 pounds per ya-rd. TRANSPORTATION UNDERGROUND. 95 The work to be done is to draw the wagons or "cars" from a " coal breaker" into the mine, a distance of about 7,500 feet, 5,500 feet of which is in what is known as No. 5 Tulnnel, near Summit Hill. A great part of the road is in a gangway in the coal of a seam overlauying that worked. As the coal is a hard anthracite, there is no danger to be feared firom fire. The working expenses of the engine for two months are known with accuracy. In order to compare theml with the cost of doing the same amount of work by mnles, we will assume the mline to be working to its fiull capacity, 600 tons of cleanl coa.l per:day. To (lo this work with mules would require the handling of 300 1"1cars" of two tons each (99 cubic feet) per day, and about 40 cars of " slate,%" " waste," etc. To haul these over 7,500 feet of roadl, requires three teams of seven mules each, drawing 20 cars in a train; there are needed, therefore, three sidings to pass trains on, and 60 cars are on the roacd at a time; there will at the saame time be 20 in the mines, and 20 outside; in all, 100 cars will be required to do the work. The wear of the roads by mules, requires the constant work of one man to keep theim in repair. To do the same amount of work with the locomotive requires but 50 cars, since the engine talkes in a train of 15 cars in less than half the time required by the mules; 15 cars in the mine and 15 outside, or say 50 in all, suffice to I"handle" 600 tons of coal per clay. There is but one'"siding " required by the engine; it is at the end of the road, andll is arranged with an air shaft to carry off the steaml and gases from the combustion of the coal. The engine has abundantly proved itself capable of draswing 15 to 18 cars, the road being so graded as to make the work of dralwing the loaded wagons out, no greater than that of taking the light ones in. Its maximnum speed is 9 miles per hour, though it does not run at that rate'uniderground "-it draws a train with ease rounld a curve of 75 feet radius. The following comparison of the expenses attending working with the locomotive and by mules has been nade: * Locornotimve pe day. Mdles er cl day, 1 engineer.. —. —. —--—.. — --- $3 50 21 mlles, at $1 per day ---- $21 00 1 boy -- 1 25 3 drivers ----- ---------------- 6 30 Repairs, oil, fuel, &Gc. —----------- 1 55 Extra cost of keeping road in repair. —--------------------—. 2 00 Total-. 6 30 Total.-.-.. —---. — ---—. O — 29 30 Leaving a balance of $23 per day in favor of the locomotive. The maen are sent in to their work on the wagons. When these are drawn in by the engine, there is a saving of 15 minutes, morning and evening; and as one miner cuts, on ail average, 14 tons of coal (clean and prepared br lmarket) per day, and has one laborer to load the same, it will effect a savillg of 30 minrutes a day for eighty-six men, or four days, at $2 — 8 per day, by using the engine for this work. The average of 14 tOllS per day is above that performed by the miners, generlly, tllroughout the anthracite mines, owing to the high inclination and great tlliekness-fitom 20 to 50 feet-of the seams in the Panther Creek Valley. In the Wyoming coal-fields, the average amount of coal mined per man per day, is about 10 tons. If we consider the first cost of the motors referred to, w e lind: Locomotive ——.. — —. -—. —--.$3, 000 21 mules, at $200................ $4, 200 50 mine wagons.-. —.. -----..- 6, 250 100 mine cars, at $:125. —------ 12, 5001 sicling, say.-................... 1,000 3 "' sidings" for passing trains... 3, 000 Total.. —-. -. —... 10,250 Total. 19, 700 Showing a balance of $9,450 in favor of the engine. R. P. Rotlhwell, mining engineer, in the American Journal of Mining. 96 MECHANICAL APPLIANCES OF MINING. Taking tile interest on the above at 10 per cent., and allowing 200 working days per year, since these minles are not worked during the winter, anid countilng twenlty cents per day for.keepin each mu-le 100 days in winter, we obtain a total saving of $7,5,65 per annum, or more thanl six cents a ton upon the coal minedl, effected by the introduction of the locomotive. The constructors state that this comparison of a few of the principal items of cost and working expenses nlay be accepted as substantially correct for tile location referred to. The actual working of the locomlotive justifies the conclusions deduced, yet its introduction is still too recent to warrant a very positive assertion that the results will always show so large a balance in its thvor. Since the data were obtained for the foregoing estima.tes, another and an improved muining locomotive has been put into the mines, and the mlanager of the colliery reports that both have proved eminently successful. Two more have since been. added to the list, aind the saving efLected by their substitution for mules is so great that it will soon cover, the first cost of the machinles. The general appearance of these locoimotives is shown by the figure. --- -'; -- -u |0.] They are built very low and compact, so ase t to pass the togh thie galleries of the heiiilllighllFt to thne stac. These loolmoti ies ll h al f to s12 uit gross loal tle capacity of the eange eig otro byreq gauge ____________' 1nfrom 2 feet 6J inclhes _tracl cand t he3 upheard-room. Tlhe mlinle-oar. Totive heigh fom 9 to _______ ___ i ____ sometimes does not!'200 po -unds eahand: work" w-ell upon pou xceed 5 -fleet f outsi _worlk_ taking _ t _he __coal to the trackde to the toly s; a Mbiting Locoalotive. of the soipke-stack. It is of course desirable, where there is ltead roon f to give greater heighlt to the stck. These locomotives will haul fron 50 to 120 tons. gross load, thes capacity of the engine being controlled by the gange of treriack and the head-ry liomite Tspae affine-locootive weigh fgan 9,000 to costr000 tornds each, and woro wotiell aponre ee r-poun rail. For outside work, taking the coailer anto th iner y so as rto eur tin ay the empty cars; atebituiniemeus coal pits for convethe coal to the point o shipment air furnaces, uarries, ake., they are built fereom fouralso to line tons in Weight, each size increasing by, one ton. All these engines are remarkably open and accessible for cleaning anto reairs, there being o part tht callo. Bu t be readily reaclied. Consir' the veri' limited space afforded by the minel gangways, the constructors of these loco y otives ave be con remarsbly surccessful in combining the boiler and machinery so as to eftcttially meet the requirermenrts of the uwork. SURFACE TRANSPORTATION. At two st of t able mines in California and Nevada, the cars sed in the hile are taken to the sPi urace anTrd se there also to convey their load the ump-ra ila or in fro the mill. t he s to the point o f (lelivery is far remnoved from the mouth of the mine, the mineral is either thrown. into enormnous wagons, to be hilau ed by horses over the common roads, or into larger cars, runnincg -upon. rail. The two mnost notable examples of mining railways in California are the road at the Pine Tree and Josephine mines, in Mariposa County, and the railway leading from the Mount Diablo mines to the point of ship TRANSPORTATION OF MINERALS ABOVE GROUND. 97 ment of the coal at Anltioch, upon the San Joaquin IRiver. The road at the former place is built froln the montil of the mines to the mill on the Mlerced River, and has a zigzag course alollg the almost precipitous slopes of Hell's Hollow. The cars, loaded with quartz, are formed into trains and descend by gravity along the steep incline, the speed of movement being controlled by brakes; the empty cars are drawn up by lmules. On the road frion the Mount Diablo collieries, the haulage of the cars is effected by locomotives of peculiar con struction, very collpact and'small, so as to pass readily through a low and narrowr tunnel. These engines work on a grade of 275 feet to the mile for one and a half miles, and on an eight-degree curve, carrying 30 tons, at the rate of twelve miles per hour. They are coal-burning; cylinders 14 by 18 inches; six driving-wheels, three feet in diaumeter; and each locomotive weighs 25 tons. These, the first mining locomotives built in California, ere designed and constructed at the Union Iron Vorks, Sall Francisco, by 11. J. Booth & Co. In Nevada a, road has recently been built fiom Virginia city, upon the Comnstock lode, to the Truckee River. In the annual report of the Gould alnd Curry Mining Company, President Bull alludes to the advantages, present and prospective, of this Virginia and Truckee railroad, toward which the trustees - had advancd $40,000. In a previous report, it was estimated that these advaintages would result in a saving of 34 per cent. in the annual expenses of the mine. Though the railroad -was at that time not yet conmpleted,. there hand been already a imarked reduction in the cost of -wood and timber. There had also been a considerable saving in the amount of supplies necessary to be on handl. At the close of 1868, the supplies at the mine amounted to over 880,00. - To have provided for such supplies for the winter of 1869-'70 would ha.rve rendered an assessment of $7 per share necessary. The railroad will permit the company to drawr their supplies as needed throughout the year, and hence the value of the supplies at present on hand a. ggyregates only about 830,000. Instead of paying I15 per cord for woodl the price has been reduced to $11 5f), whlile for spring delivery contracts were offered at $9 per cord. At the mines of the Red MIounltain Comipany, Silver Peak, Nevada, there is a fine surface railway, albolt a mile and a half long, and remarkable for the boldness of its curves and grades. The loaded cars descend upon it by g'ravity, and the empty cars are drawn up b)y mules. The road winds along the mountain side, "' eading" the numnerous canfons, untltil it arrives at a point above the larger dumps, lwhere the ore is to be d(eposite(l to be removed in wagons. The remaininog descent to the -lllumps could not be traversed by the road, even with such curves as h ad been employed above, except by enormnosly expensive trestle-work or masonry. The only practicable route required an acute angle in the road, and this was in fect introducecd by means of a back switelh the suogestionl I believe, of 1Mr. J. E. Clayton, the superintendent. The track runs past the point of turning, and, for a few yards, up hill. The car, rrapidly descending', shoots by the switch, and its velocity is diminishied by the lup grade. It is stopped with the brakes, the switch is changed, the brakes are opened, aindl the car starts again by gravity, and runs back to the switch, where it is deflected upon the next descent at an acute angle to the last. The whole operation is perforLmed in a few monlelmts by one man. By the use of such back switches, a surface tramway may surmount great difficulties of groulcl at smaill cost land trouble. The dumps of this company are like those of the Comstock mines. The ore is taken from them by large "back-action" wagons, 7 in 98 MECHANICAL APPLIANCES OF MINING. and hauled six and a half miles further, to the mill, over anl excellent wagon road, constructed at great expense, and presenting so uniform a down grade that fifteen or twenty tons or upwards can be hauled on it by a team of eight or tenl mules. It is my impression that the wagonroad cost about $20,000, and the railroad about 815,000. TR'ANSPORTATION UPON WIRE ROPE. Mr. Charles HEodgson is the author of a, system of transporting by suspending the load lupon a moving endless wire rope. This rope is supported on pulleys sustained by posts about seventy yards apart on the average, passes arounid a clip-drum at the end, and is worked by an ordinary portable engine. The rope moves at a speed of about five or six miles an hour, andl the boxes suspended from it carry friom one to five hundred-weight each. They are so attached that they pass the pulleys with ease. The full boxes hang on one side of the supports, and the empty ones on the other side. About thirty-five miles of line have been completed, and about one hundred nmiles in length are constructing. The cost of a line capable of transporting one hlndred tons a day is about ~400 per mile, and the average cost of transportation, includinog maintenance, is about twopence per ton per mile. TRAI3MIING UPON A FIXED ROPE. An interesting example of transportation upon a stationary wire rope, used as a track, stretched tightly upon posts, is found at the Brown. mine, Colorado. This mine is on a steepl) mountain slope, about sixteen hundred feet from the mill below it, andcl the rope is used to convey the ore froll the mouth of the mine ____ ct__- a to the muill. Two one-and-a-quar-> di ~ - 3 ter inch wire cables are stretched between the two points, one for the descent of the loaded cars, the \ iother for the ascent of the empty cars. The cable is sustained upon the projecting end of a horizontal beam, d, tipped with an iron bar, e e, as shown in the annexed figure. Its upper surface thus forms anr unbroken track. The cars f are suspended -upon it by means of a curved frame-work of iron, y, in which there are two wheels, with hollow faces to fit the curvature of the cable. The descent of the loaded car, draws up the empty ones on the other track by means of a small iron rope, half an inch in diameter, by which also the speed is reguTransportation of ores upon Wire Rope. lated. AUTOMIATIC DUMIPING. At the Mount Diablo mines, California, there is, at the Hope colliery, an automatic arrangement by which the mine cars empty themselves HOISTING MACIIINERY AND APPARATUS. 99 into the bunkers. The forward end of each car is closed by a flap-door, hung upon a rod. at the top in the usual manner, and secured by a latch. As the cars come to the surface, each one is switched off upon a separate branch trackl leading to a little platform at the head of the screen, over which the coal runs fromT the cars into the bunkers. This platform is just wide and long enough to receive and hold one car, and is hulng upon trunnious at the side of the tra ck, and about two feet higher than the rails. The T-rail'is usedl upon the platform, and at the front end of the latter the rails are curved upward and backward for eighteen inches or two' feet, so as to fit and receive the forward wheels of the car, and hold it upon the platform while the whole tips forward. As the loaded car runs on the platform the wheels strike the curve of the rails, alnd the car is stopped; but as the centre of gravity of the loaded car is somewhat higher thali the trunnions of the platform, the momentum tips the platform and car forward and the load is discharged. As the car tips forward, the latch strikes against a bar of iron and is withdrawn, so that the door drops open. The larger cars, in which the coal is transported to the vessels at the river, are discharged by a similar device, excelpt that the platformn is tipped by a hand crank and gearing. The arrangemnent of the small cars for automatic dumping is similar to that at Blanzy, except that there the rail is re-curved backwardls far enough to includle both wheels, and the forward wheel, instead of striking the rail, abuts upon a piece of timber by which the shock is deadened. The trunnions are bolted to a vertical plate of iron, which supports the track below, and is prolonged above so as to overhang the body of the car, and help to retain it whenl inverted. OILING THE AXLES OF TRA-i WAGONS. A contrivance, known as Halliday's, for oiling the axles of tram wagons or cars, which has been in use for some timue at Mlesne Lea colliery, England, consists of an1 open vat, or tulb, placed under the track and fitted with a small force puinp in the center. This pump has two spouts or jets, drawn to a point, like the tube of an oiling cup, and then rising to the level of the axle-bearings. Oil being placed in the vat, and the car having been ruln over it into the proper position, so that the jets are opposite the bearings, the attendant presses with his foot upon a lever, which moves the piston of the pump and throws the oil into the bearings. The excess drips back into the vat, and is not wasted upon the ground, as is ordinarily the case. CHAPTER IX. HOISTING MACHINERY AND APPARATUS. The simplest form of hoisting apparatus is the common hand-windlass, with a bucket made of the half of a barrel, familiar to every miner. In Mexico, and frequently in Arizona and Nevada, the bucklet is represented by a rawhide sack, which has the great advantage of being light, strong, durable, and cheap. There are no hoops to fall off when it is dry, aR.nd it cannot be stove by falling down the shaft. Experiments have been made with the windlass in Great Britain and on the continent. WVeisbach says that two men can raise a weight of 17 pounds 2.4 feet per second in a pit 120 feet deep throughout a period 100 MECHANICAL APPLIANCES OF MINING. of eight hours. This is equal to about 8 tons 12 hundred-weight per day. Mr. Walker, in England, supposes two men raising coal from a depth of 150 feet. One man can exert a force of 12 pounds at a speed of 220 feet per minute. To convert into foot-pounds, we have: 12 x 220=2,640 foot-pounds. Then, 2,640 x 60 minutes x 8 hours x 2 men x 150 feet=7 tons 10 hundred-weight 96 pounds, raised by tihe two men in a day. This shows theoretically what can be done. Practically, such results are not attained. As the depth of the pit or shaft increases, a horse-whim is substituted for the windlass, and this in turn is displaced by water-power or a steaml engine and hoisting gear, with horizontal winding druimis. Horse-whims. of good construction have drunis from eight to twelve feet in dialzeter, but they are often larger. The arms attached just below the druml are from 30 to 36 feet in length. In AMexico xwhims of enormous dimensions are constructed for hoisting froim the large and deep shafts, and they, require ten or twelve horses. As the strength of the hoisting apparatus is increased, the size and weight of the buckets are made to correspond, and iron is substituted for woodl, or the tubs are made of plank and are heavily ironed. ITI13B3LES. Probably the best form of mining bucket, andcone which is more or less in use in California, is the Cornish kibble, a cylindro-conicald vessel, made of iron, in plates one-quarter of anl inch thick, and strongly riveted together, as shown in thle figure. A kibble of nmediumn size weighs three hundred-weight, and has the following dimensions: height, 34 inches; dianieter at the top, 22 inches;'it the bulge, 24 inches; at the bIottom, 15 inclles. Tme charge is seven lChundredC-weight. But this weight is too great for horse-whims; and for these the kibbles are mlade smaller, weighing fromn one to one and three-quarters lhundred-wreight, and holding a. mean charge of two hundred-w xeighlt. k \ V'"'i,>~ At Dralkewell's Cornwall, some years ago, libbles were'uin use weighing 41 hunldred-lweight; charge 1-5 thundredi weight; height, 36 inches; diameter, 33 inches.' When a loaded kibble is brought to thle surface it is CornIish Kibble inlverted and dcischargedl by inserting a hool, at thle end of a hanging chail, in the loop at the bottom; the kibble is then loweredl and becomles suspended by the bottom rwhile the load falls ott. SIKIPS. Kibbles or bulckets swinging freely in the air call only be ulsed in large and vertical shafts, where there is room for themli to ascend and descend without striking the sides. In narrow shai-fts, and particularly ill those, which for a part of the way are not perpelndicular, but inclinled, it becomes necessary to confine the b-uckets to a certain path, and this is done by means of guides placed along the sides of the shaft. Buckets or boxes so guided are known as skips, aldlc have been much used in Cornwall and in some of the gold mines of California. Thle annexed drawing of a skip usedc at the Princeton mine, Mariposa Estate, will serve to show the construction. It corisisted of a rectangular box, made of boiler-iron, one-quarter of an inch thick, and strongly riveted with angle-irons in the corners. It was 5 feet 5 inches in its greatest length, and two feet square in section. The wheels, one foot in, diameter, ran HOISTING MACHINERY AND APPARATUS. 101 upon short axles bolted to the side of the box, and served to support it when passing along the inclines, and to keep it in place when rising between the vertical guides. These guides were of wood, 5 by 6 inches square, and faced with a straprail. Short bars of iron, or "rubbers," projecting fromn the skip behind these guides, together with the wheels in frontl, served to keep the skip in position. The bottom was made inclined, at an angle of about 45 degrees, as shownT in the figure, and the load was discharged through a flap-door, secured by massive hinges inl front. On rising to the top of the shaft, it throws open two oaken trap-doors, which fall back arnd close the opening as the skip passes, and in the descent of the skil) for dclumping, its inclined bottom rests upon one of these doors, inclined at a similar angle. The door serves also as a chute to direct the load into a car placed to receive it below. Whenl the Princeton mine was in its best conditionl and worked with most vigor, the hoisting was effected through three shafts, all within a distance of about 500 feet, and with three engines. They took out an average of 180 tons a day, working one shift of eight hours only, for a long period, and sometimes 200 tons a day, hoisting in skips, a ton at a time in one, andc 900 pounds in the other. The main shaft, where the largest amount was hoisted, was at that time 330 feet in depth. Skip —Princeton mine. The skips in. Cornwall weigh from 6 cwt. to 94- cwt., and the charge varies from. 11 cwt. to 124 cwt. Skips are applicable, especially in mines with inclined or crooked shafts, where for a part of the course the hoisting is upon a slope and in. another portion is vertical. At the Amador mine, (Hayward's,) instead of skips, cylindrical iron tubs, guided along the slope of the shaft by two strong stringers of timber faced with iron, were in use for several years. The cylindrical form of the tubs perinitted them to rest in the angle between the two guides, and a rounded rimn at the top and projectionl at the bottom were the only points of contact with the guides; the body of the tub was thus kept from wearing. These tubs were about six feet long' and twenty inches internal diameter. By this arrangement of the two tubs, one descending while the other was ascending, both the ore and water of the mine were brought to the surface. Pumps have siince been introduced for raising the water, but I believe the ore is hoisted as before. COST OF HOISTING IN CORNWALL. Some interesting data in detail have been published by Aons. M1. L. Moissenet* in regalrd to the cost of hoisting at several of the most prominent mines of Cornwall, England. He finds it to range from one shilling and twopence to one shilling and elevenpenlce per ton for depths ranging from 150 to 250 fathoms. Four examples are cited: Dolcoath, where the hoisting is by kibbles and chains in inclined and elbowed shafts; United mines, where skips with flat ropes work inl a vertical shaft; Levant, where skips, with flat and wire ropes, work in an elbowed shaft; and Carnbrea, wnhere kibbles, witIh chains and skilps, with * Doe 1' Extractionl dllarsls mines u Cornwall, etc., par M. L. Moissenet, Ingenieur -des mines. Annales des Mines; II, 1862. 102 MECHANICAL APPLIANCES OF MINING. fiat and wire ropes, work in various kinds of shafts. The particulars in each case extend over a period of twelve motnths, and tables are given for each mine, showing the quaitity hoisted and the cost of nmaterials used, not only in the shaft but at the engines, and in filling and landing. Froml the various tables I have compiled the following, showing the mean depth, the quantity extracted in tons, the cost per ton, and the cost per ton per 100 metres at the four different mines. Name of Illine. M3ea.n depth. ulantity exs- Cost p rer tolnper tracted, tons. er 100 minetres. Fathomns. Metres. Tozs. s. cd. Ircacs. Fraics. Dolcoath...-....-......-..... 250 -- 457. 19 20, 166 1 11= 2. 3981 0. 5212 United Mlines -.....2............ 240 = 438. 96 19, 200 1 7 = 1.9440 0. 4418 Levant -----—... — 190 = 350. 00 16, 800 1 2 = 1. 4313 0. 4089 Carnbrea.................-... 150 = 274. 00 36, 000 1 6-= 1. 8857 0. 6977 At Dolcoathl a little over 42 per cent. of the cost was in the shaft, 37 per cent. at the engine, and 21 per cent. (nearly)for for filling and landing. HOISTING M3iACHINERY IN CALIFORNIA AND NEVADA. The simplllest form of steam hoist, and the one usually employed in California and Nevada, for depths of a few hundred feet, especially if used in connection with. pumps, is a steam engine with eight to tenl inches diameter of cylinder and sixteen inches stroke, with or without link-motion to the valves, the engine only requiring to run one way. Upon the crank shaft is a pinion, grooved generally with a large V, the inner faces having an inclination toward each other of 60 to 90 degrees. This pinioi. gears by friction into a large V-wheel, proportioned to the size of the other, so as to hoist in the shaft from 200 to 3)00 feet per minute. This large V-wheel usually forms one flange of the windinig drum and upon the opposite end of the druml is a second flange of the same diameter as the V-wheel, but with its periphery broadly recessed to receive a friction strap. The winding drnuln is mlade of boiler-ironl, and is riveted securely to a projecting rim cast on the inner side of each of these wheels. The dimensions of this drum are usually 2 feet 6 ilches diameter by 2 feet 6 inches long. The diameter of the large-fiiction Vwheel is 4 feet, and of the bralke-wheel the slame. The whole is keyed upon a shaft 31 to 4 inches iln dia.meter, anld is lotnllted upoin a xwooden framne swinging lnupon a hinge. BIy means of a, lever the large V-wheel is pressed firmnly into contact with the fixed piinon on the engine shaft while hoisting. While lowering, it is thrownr out of contact, and being perfectly detached froml the engine, is free to unwind, its movement being controlled by the application of the fi'iction band. The motion of the engine is controlled by the throttle-valve, and continues aIll the time in one direction, it beingl used onlyl dluring the hoistinog. This construction for a hoisting eng'ine is simple, d(urable and conlparatively safe for small loads an(d shafts that do lnot exceed two or three hundred feet in dlepth. For deeper mines andl heavier vwork the drum-shaft, is supported upon a frame which slides uponl a secure bedl, and can be pressed up to the V-pinlion by levers, anid the friction sIurface is increased by making several V-grooves instead of one, and giving themtl an acute angle. Where two or umore shafts are to be worked HOISTING MACHINERY AND APPARATUS. 103 from the same engine, a man is placed at each brake. Some engines dri-ve as many as four winding drums from one crank-shaft. One of the disadvantages of this mnethod is the unequal wear of the V-wheels, which require turning off as often as twice a year, and somnetimes once in two months. Hoisting cgear of the kind just described is manufactured by the Union Iron WVorks. By imeans of long levers the engineer can control the engine while standing at the mouth of the shaft. The piston of the engine has two-feet stroke, andcl the fly-wheel is eight feet in diameter. The winding drulm is three feet in diameter and three feet in length. Tlhis construction is characterized by extreme simplicity andllgreat strength. Another form of hoist much in use for the mines of the west ris-:the common link-motion engine, with a light fly-wheel fitted with a good -/:.- -.- - -.....'n _ u. -"'. W, Booth & Co.'s Hoisting apparatus-pelevation. _ s / \...,,_ t! 1112R ilt I' 1 ____ _y =.s. /'.__. __. Booth & Co.'s Hoisting applaratuLs-plah. brake, and a strong flanged pinion upon the end of the crank shaft, This pinion gears into a spur-wheel, keyed upon the shaft of the wind. ing drum or reel. WTith this construction the engine and tihe win diinp 104 MECHANICAL APPLIANCES OF MINING. drum canr be turned either way, and if two skips or cages are worked at the same time and froml the same level in the mine, the cables are wound so that one unwinds -while the other is winding up, one thus balancing the other. But where the points of depar.Lure in the hoisting change, one reel or drum is miade with a hub-flange or clutch, so that it can be easily adjusted to wind frolll a greater or less depth, as required. In mining requiring a sudden chalnge of distance of hoisting, (from either an upper or a lower level,) each reel and wheel should run independently and have a separate friction band. The pinions on the crankshaft are fitted with a clutch, which can be thrown in or out of gear when required to lower. The engine is ucnder the control of one man, and each brake and reel under the control of another. When the bell strikes for either reel to hoist, the engine-man slows the engine to allow the clutch of the pinion to be put into gear. The brakemlan then releases the brake and the hoisting commences. For stopping, the clutch is thrown out and the reel is held by the friction brake. In this way two or four shafts can be worked from one engine, and to any number of levels. The above-described form of hoisting apparatus is illustrated by the annexed cut, giving a vertical and a side view of the machine with its foundation', as made by H. J. Booth & Co. It is here shown with a single bobbin for a fiat cable; the spokes of this bobbin are of wood, and are not joined together by iron segments. HOISTING AT THE?IMOUNT DIABLO COAL MINES. At the Mount Diablo collieries the coal is hoisted in cars up a slope of 370 and 327 feet long, by an engile with a 14 by 30-inch cylinlder. The crank-shaft carries a fly-wheel 12 feet in diameter, and a I)inion 2 feet in diameter, geared into a spur-wheel 6 feet in diameter, which forms the end or flange of thle winding drum. There are two drums, so connected by a clutch gearing that they can be easily discolnected at a:ny time if desired. These drums are of iron, covered with wood, and are about 19 feet in circumference. A powerful brake, worked by the foot of the engineer, is fitted to the circumference of the fly-wheel, anltd is capable of stopping the engine very quickly. The engine makes 120 double strokes in a minute, and the usual time of hoisting a car carryilng about one ton of coal is thirty seconds. Only one car is hoisted at one time, and about 200 are drawln iup in the course of tenl hours. But this is not the limit of the working capacity. As many as 2'70 have been taken out in that time, and the num1ber could be exceeded if desired. }Round iron wire rope, - of an inch in diameter, is used, anld passes over rollers about 3 feet in diameter. In some of the pits a flat wire rope, winding upon a reel, has been substituted. At the Pacific Coal Mining Companiy's mines, near Mount Diablo, a very well constructed shalft was sunk verticall7 to a depth of 4500 feet, and was provided with excellent hoisting works firol thle establishment of H. J. Booth & Co. The engine of 75-hoise piower was geared to a bobbin-shaft. There were two bobbli3s, wadinl(nig inversely; fiat iron cable, balanced; a link lmotion, and an ordinary bralike, o)erated by the foot of thle ellginleer. Thle pmnlling was t)erforml'ld by a, separaete engine of 150-hllorse lower 135-ilclt I)lunt'er, aclnd a lift-pumtlp. IIOIS TING- UPON THI-E COMIS"TOCIK LODE. Upon the Coinstock lode, in -Nevada, prf.(eli1rtc: is given to one heavy, HOISTING MACHINERY AND APPARATUS. 105 short-stroke engine, with balance valves anid link motion; a pinion upon the crank-shaft; heavy spur-wheel, and flat winding cable. The mines on the Comlstock lode which have large hoisting works and wire cables include the Chollar-Potosi, Empire, Gould & Curry, Hale & Norcross, Imperial, Lady Bryan, Savage, and Sierra Nevada. An engine recently put up by the Risdon Iron and Locomotive WVorks, of San Francisco, has a 20-inch cylinder with 40-inch stroke, with 3 feet 6 inch pinion, 12-feet spur-wheel, 14-;inch face by 3-inch pitch, a single winding reel for flat cable, 5 feet in diameter, sheave, or shaft pulley, 8 feet in diameter. WTith this it is intended to work fromn a depth of 2,000 feet. HOISTING IN GUIDED CAGES. In each of the methods described the mineral, having been taken to the shaft, is either dumped in a pile and then shoveled into the bucket or skip, or is ndumped through a chute directly into the skip, and the empty car is returned to the face. But this necessitates a rehandling of the mineral, which, whenll it reaches the surface, must be again dumped into a car or wagon, by which it can be delivered at the proper point away from the shaft. These and other considerations have led to hoisting the car and loadcl together to the mlonth of the shaft. This effects a great saving in time, labor, and wear and tear of apparatus. It is the method adopted in the mines upon the Comstock lode, and in all well-appointed vertical shafts of any considerable depth elsewhere. To effect this, a compartment of the shaft is fitted with vertical stringers, or 1" guides" of wood or iron, extending fiom the top to the bottom, whlich serve to guide the movement of a platform cage, into which thle car can be placed. The 1platform is fitted with rails of the same gauge as the track, aind the car is rolled upon these and securedl by bolts. The platform is a little smaller than the conlpartmnent of the shaft, and forms the bottom of a framework of ironl, by which it is suspended. The frame rises above it on ea;ch side and connects with a cross-piece above the car, to which the hoisting cable is attached. The platform and the framework together form the "cage." By means of projecting ears or bars of iron or steel rubbers on each side, at the top and bottom, which partly embrace the guides, it is kept from contact with the sides of the shaft, and thus glides freely up and down. The only friction is between the rubbers and the guides, andl this friction, in truly vertical shafts, is very slight. The shaft becomes, in fact, a vertical railway, and is a continuation of the tramways below, uniting them with the distributing tracks above. Tramming antd hoisting thus become a connected and continuous operatioin. A carload of minera.l is rolled to the bottom of the shaft and placed upon the platform, the signal is given to the enginemnan above, and the load starts upon its vertical journey. Miost of the mines at Virginia City and Gold Hill, upon the Comstock lode, and in other parts of Nevada,, and the principal deep mines in California, with vertical shafts, now use the cage. It is single, large enough for one car only, but the hoisting is very rapid, from 500 to 1,200 feet per minute, (S ft. to 20 ft. per second,) and with heavy loads weighing fromn 5,000 to 8,000 pounds. The construction of the cage, as I have remarked, is very simple, being usually a squarve planku platform with a track, npon which the car stands, and suspendled by a kind of stirrup-friame of iron at each side to an arched cross-bar of iron at the topl, througlh the center of which the rod of suspension passes freely, anid is firmly bolted just below to a 106 MECHANICAL APPLIANCES OF MINING. i i Side view and plan of one end of the Safety Cage in nse in Nevada. HOISTING MACHINERY AND APPARATUS. 107 second iron cross-bar, free to move up and down in slots made in the framne on each side. This second cross-bar is connected at its two ends by arms on the outer side of the framze with the lever ends of dogclamps or safety catches. The construction will be more readily understood by reference to the figure, giving a side view of the most approved jU-U ~ -0 o o o0 oo 0 0 0 o:o 11 0','o o d~t. A _'t: 0-:::q:: I X. 0 /.,o0 0 ( 11'11' - - - - -. a 0 f C/q 0 — o. rrn ~ i~lo o / / 0 0 / / forlm of tle cage ancl catch, nov inluse i-1the m-ines of the ComDstock lode. Tlhe platforml P P is five feet loig aind1 -ltree feeteight iiel-les wvide. It is surmnountecl by a hood, H 1I, of boiler-iron, firmlly secured /20 form~~~~~ ~ oftecgInIac, lwi s ntemie fteCmtc lode.~~~~~~~ Th/ltom PPi iefe on n he etegtice wide.It i suroutdbahodIIIobolriofmyserd 108 MECHANICAL APPLIANCES OF MINING. by hinges to the top of the frame, and designed to protect the miners from falling bodies. The height of the cage from the top of this hood to the bottom of the platform is eight feet. The ends of the rubbers are seen at R IR and R' R/; the clamps, or safety catches, at C C; and the arms A A, connecting these with a cross-piece above, B' B'. A safety hook, S, for detaching the cage in case of overwinding, is placed at the top and turns in the head of the suspending rod. When the cage is at rest at the bottom of the shaft, or whenever it is not suspended by the winding cable, the cross-bar B B, and cross-piece B' B7, are pressed downward by a long and powerful steel plate spring, and this throws the points of the catches C C into the sides of the guide-timber, and not into the face, as is the case with Fontaine's and other safety catches. The construction of the upper part of the cage, including the spring and the suspension rod, is not shown in the side view of the cage, but will be seen in the second figure, giving a front view. During hoisting or lowering the spring is compressed, and this serves to relieve the cage and load from the shock which attends a sudden commencement of hoisting. The hand-lever just above the platform controls iron rods which rise through the floor of the cage and hold the cars securely in place during the ascent and descent of the cage. The whole construction is light and simple, and has given general satisfaction. It is not closed in at the top and sides as closely as in the foreign mining cages, and is high enough to allow miners to stand upright as they ascend and descend. The hood is hinged to prevent the imprisonment of miners in case of accident, or drowning, if, as sometimues happens, the cage is lowered into water. EUROPEAN GUIDED CAGES. In Europe cages are made in a much more substantial and cumbrous manner, and they are generally arranged to receive several cars, either one above another upon separate platforms or. when the shaft is wide enough, two or three abreast. At Mons, in shaft No. 12 of Grand Hornu, eight wagons have been put into one cage of four stories. When the wagons are large, as, for example, those of twelve hectolitres at Blanzy, the cages are only two stories high. They are usually made of iron, on account of both lightness and strength; and the angle irons and T-irons are found to be well adapted to the purpose. The cage of four stories was the form in use a few years since at Anzin. It is made of angle'iron, strongly riveted, and weighs as follows: Kilogrammes. Plate and angle irons.....- - - -..... - 655 Sheet iron.-.....-.......... —-. 220 Cast iron...-....................... 32 The safety catch, (parachute) -.........-......... 218 Total weight of the cage.-1.............. 1, 125 This cage will carry 2,000 kilogrammes of coal in the four wagons, which themselves weigh 720 kilogrammes, thus making the dead weight as much as 1,845 kilogrammes. The cage used at Charleroi holds four wagons, like those at Anzin; HOISTING MACHINERY AND APPARATUS. 109 but tlley are here placed end to end upon two floors only, and the cage weighs 900, the four wagons 780, and the charge 1,600 kilogrammes. At the Paris Exposition of 1867 Nicholas Libotte, constructor, of Silly, near Charleroi, exhibited some cages intended for the collieries of (Charleroi, Belginnl. These cages are remnarkable for their extreme lightness and strength, and for the perfection of the forging. They are made of steel, are intended for a narrow shaft, and are capable of talking six wagons, one above another. The cage weighed as follows: Kilogrammes. Cage...........1..........................-.-. 1, 434 Parachute.-12.....8.....-.... —-.. 128 Total1....................... -..... 1, 562 Another cacge, similarly constructed, was made in two stages only, but was also designed to receive six wagons, three on each stage: Kilograinmles. Weight of cage.................... 17 268 Weight of parachute. ------- - - -------- 164 Total. —.-....... —.. — - - - 1, 432 This cage was made for a shaft near Liege, Belgium. In order to dcliinish the shock which results from the sudden descent of aI cage upon the platform at the bottom of a shaft, especially when the cage is used for the descent of miners, caoutchonc springs have been placed -under a false platform or landing, so as to prevent violent concussions when the motion of the cage is not sufficiently arrested in season to avoid a shock. So also, in order to avoid the sudden shock at the commencement of hoisting, spiral springs have been placed between the end of the cable and the top of tlhe cage, so that the spring would be compressed before the cage began to move. Blut such springs require to be very strong and( heavy to be of any service where such great weighlts are to be lifted; and this has led to the plain of placing large steel plate springs under the axle bearings of the great pulleys at thle top of the shaft. But it is also desirable to have an elastic form of attaclllert to the eages; and this is secured to a certtain extent by the use of the sflfety-catch, which requires a spring. CABLES, ATiIRE TIOPE, WVINDING DRUMIS, & C. Tile leading mines upon the Comstock lode extend froml 1,000 to 1,300 feet below the surfice. In nearly every one the companies have changed their lhoisting works severial times, increasing their power and improving their construction to suit the increased duty of winding from constantly augmenting depths. Hemp cables have given way in part to rounnd wire ropes, and these in turn to flat wire cablles, some of them made of steel wire. The dimllensions of these flat cables are 3 by 1 inch to 6 by 1- inches for iron, and 21 by T inch to 4 by ~ inch for steel. The length is usually 1,500 feet. The manufacture of wire cordage and flat winding cables for mines is carried on in San Francisco upon an extensive scacle at the works of A. S. Hallidie, erected in 1857. Their capacity of production is now over 1,200 tons of rope and cable annually. Their manufactures embrace 110 MECHANICAL APPLIANCES OF MINING. every description of wire cordage, from the delicate bell and signal cord to those of a single piece 3,000 feet long and weighing nearly 40,000 pounds..Most of the hoisting works upon the Coinstock lode have been supplied withl winding cables from this establishment. This firm has recently made a cable for the Imperial mine 1,600 feet long, 6 inches wide, and - inch thick, weighing 8,400 pounds. This cable is wound upon a 6-foot drum, but as generally several layers of the cable remain on the drum, not being unwound, the diameter is increased to 6~ to 7 feet. The sheaves for flat cables are usually only 7 feet in diameter, but this is too small; they should not be less than 12 feet. DTAMETER OF WINDING DRUMIS. It is a common defect in all the hoisting works of California and Nevada that the winding drunis and pulleys are too small. In Europe the diameter of winding drunms has been greatly increased, and there are many exaimples of drums 20 feet in diameter. At the Casilir Perier colliery at Somaiin the round wire rope is used upon a druml. with a diameter of 7111.14, or 25 feet. Twenty-five turns of this drum winds up 600 metres of cable. The weight of cable is four kilograms per metre. These large drums are particularly desirable for wire ropes, which are dlestroyed very fast by a short bend. On these large cirumferences the turns are fewer, and the cable need not be coiled several timnes over itself, which causes great wear and destruction of the strands. Each turn of a drum 22 feet in diameter represents 66 feet of length of cable, and 25 rounds will reach 1,650 feet deep. With a rope one and a, half inch thick the drmn would have to be a little over three feet in length. In such a case the radius of the drum in winding would remain the same whein wire rope is used; but this is not the case with hemp rope, which has a much greater diameter, and whenl winding up around the druml it must coil upon itself several times, and thus increase considerably the radius of the drum, and, on the other hand, in unwintdindg or lowering into the shaft the radius of the drum is rapidly reduced. The difference of radius is insufficient to compensate for the weight of the unwound cable, and sLch an arrangement requires powerful engines to lift up the dead weight of cable at the start. From that moment less andl less power is required until the two buckets or cages meet in the shaft; then the descending cable gradually takes the advantage of the ascending one, and the steam-engine, instead of driving, is soon drivenl with an increased velocity by the increasing weight of the descending cable. To avoid these inconveniences a system of counterpoises is used. Ropes carrying a counterpoise are wound around sheaves placed on the shaft of the drum; these counterpoises play up and down thle shaft for about fifty or sixty metres; the cable unrolls as it goes lown, and the radius of the sheaves diminishes. It is so arranged that whenl the entire cable is paid out and the counterpoise is down the two buckets or cages pass each other in the shaft. At that time the strain upon the hoisting drum changes, as also the action of the couiterpoise. Therotary motion of the hoisting drum continues in the same direction, as also that of the sheave, which now winds up the rope of the counterpoise in the opposite direction. The force required to raise up this counterloise counterbalances the weight of the descending cable. Another way, which gives better results, consists in using a very heavy cast-iron chain as ai counterpoise. MI. Quillacq, a Belgian engineer, after having visited the hoisting HOISTING MACHINERY AND APPARATUS. 111 worlks of England, and examined the system of counterpoises used there, proposed to place the winding bobbin directly over the shaft, and thus to dispense with the sheaves. Drums seven metres in diameter are placed on the top of the shaft, instead of the sheaves, and are driven directly by a double-cylinder engine. This system, which is fully described in " Le lfateriel des Houilleres," by Professor A. Burat, has not been entirely successful so far; but it has shown, however, that an economy of fifty per cent. can be realized on the wear and tear of cables. Although difficult to do away entirely with the sheaves, it is quite easy to increase their diameter so as to avoid giving a short bend to the cables. It has been suggested that a series of rollers or small sheaves, placed on a curve of large radius, might advantageously be used instead of very large sheaves. STEEL-WIPRE CABLES-WVEIGHT AND STRENGT-H OF CABLES. The use of cables mlade of steel-wire has been highly recommended on account of their superior strength and lightness. In practice abroad the high hopes entertained of the value of these cables have not been realized. The wire undergoes rapid changes, and has been found after five or six months' use to become brittle, so that the cable could no longer be relied upon. Some of the fiat cables now in use in Nevada are made of steel; but no data regarding their weight and wear have been received. The following table exhibits the size in inches of flat cables, their weight in pounds per fathom, their working' load and breaking strain.*I have added also a valuable table which has recently been publishedl, giving the comparative strength of iron, steel, copper, and hemp cables, expressed in dimensions and weights of the metric system.f From HiunLt's edition of Ure's Dictionlary. t From Etudes sur les Arts Textiles, &c., per Michllel Alcan:, p. 34. Aplproxinutte dintensions, weiyht, t~and strength of round and fiat cables of iron, steel, copper, and hemp.. ROUND CABLES. FLAT CABLES. STRANDS. II-oi. Steel. Copper ]reain, IIroil. Sel Copper. Breaki n Iron1-. Steel. Coper.ii strain o I I strain and strain an-d ofr the sam liees cables L i~ emip'strand: d Laiameter.11 ~ o' th /aie ~ 4I 4- ~ of the same. 7Z ~ ~ ~~~~~~~~~~~~dimensions. e.. 4 ~ ~~ ~ ~.4 ~ diameter. C~ ~ ~~ ~' C; CZ -C'.) C- ct5' a.,-,~'a,., =.. aa' / ~~~~~~~~~~~~- ~ C,.~~~~ t~ to tE to CE~~~~~~~~~~~~~~~~~~~~~~~~ 4. 4. 4~~~~~~~1 4-Z Q., 4~~~~~~ x~ 1= C) 7, 4-,~~' ti t C to to~~~~~~~~~~ k. 7e. 7e. g. L k- g le 7~~~~~~~~~~~~~~~.. j./7.g i?,. /k. k. k. Ig.. Ie k. q c.g k. k. k. Lg. 7.1k 0. 005I 0. 10 7' 4~ 0. II /C,19. 1 8 6 6 0.I k2. 0/.6 - - - - - -- - - - - - - - - - - -- - - - -.I 00c. 016 19.l 01 9k. I1 99 P..00. O. 007 O1853 1,12 0. 16 2,31O20 07 179/ 0. 0015/0 ---- ------- ------ -------.02.0128 21/ 0. 011 1352 0. 032 169: 0. 004 ~~~~~~[0.1005,19 O. 4o o: O. 2OO894 0.0418 41194 0.01761 19080 o.A. 018 —--------— / —-- -— 9 —-! —----— t/036 0 61472:06.006.01 9 4'. 2 0. 016O563,906;dU 6~2.623,-9 4 0.1/ 13 7 O.00 —- -------------- --- ----—:.0420 8 4.08, 070 07 59 61 3 0. 0 13 95[ 0.61 4 4,64,3] 0. 10 6533 0349410.01 7.3317,813 7.843 29630' 2.921455]178 0. 0161 0.021- 381161 701.796,S. 02131, 23 6691 1 05 0. 0:?,74-.081 3. 1 351 15:00. 035 o. 014~1 o. 74~1, t460/. 743l 5 210, 0 0 10.0539 4, 30......... 7.1.............. 0. 8 ---------------------— 0.00248 0.028 2114 0.01$[ 35'407 0.0326 1704/ 0. 040 O. 00t 6[ 0.9341 6, 5213 0.2935 0-j8 265] l, 344/ 90570. 27 017::6. 001~412, 260 6/ 03. 076 33, 77831 3.418/1, 891"2.79315. 593 7 o. 0034 0.10 69 o. 0341 45 78o. 060 891 I5N 0. 012 0. 0 IS(! 1. 158 8,04 621331.3tC) 2 J - L 200 0987 —--— / —- ------- --- ------ O. 000". 73139 0. 1074'3190.18i 09 P40.02 o. oo0 o. 89 21, 010/ o. 6038 19,60 070.6: /1........]...]....1...[... / 3 0. 024~~~~~3,2 3 3014 6o.. o1 o] o 2,~24. 003892 0 o., 0 43 330/ 1 0. 043 15 1.8871 50 O0. 90418 521.39,91 37'5 o0 6.560. 0815.362 0.374 OS0 O2 0 -2, 1 O. 0 1.65I,099[ 2O64~9 )S2.395009 2, 4369 O. 3592 4, 0948 O. 3`146 2, 474 28 330.':40,i O.,03~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~050.34 233 2:3 3.3807138, 6501 3. $23[4',97119 4.6 33312126 35'5 809 88. 0033', H O%,5St.15.- 306. 0477,251,513.18000 2 /0 5 3,8139 O. 5053 636;50.7 030 178 359 O. 101 O. O048 [ O. 4397 8 62 0 S.4. 4701 9, 0964 9. 55 49,/o o,01 8,,~ o. 07, NW.,~ -- -- -- - -- - -o - - -- - - --- - -- - - - - -- - -. 016.2 4 9 1.2 91, 3.4 1 8 q 6 9 7 0 5 5 7~~~404 O. 43C — - - - -- - - - -- - - - - -- - - ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~0. 0531110. 074169 5579 0. 11.1,991.4073/ 49629,0 07,1501148.111-13 1.70893 464 52O 0. 541 Th imninsi ti abeaesatdi Iatin f itr te-eijtsi ilaainsan rl-nes n tebeai~gsrini hlgaois HOISTING MACHINERY AND APPARATUS. 113 Table showing the size, iweight, and strength of flat cables for mining pu1poses of hemp, iron, 1antd steel. HEMP. IRON. STEEL. EQUIVALENT STRENGTH. Size in Size in Size in Working Breaking inches. eit per inches. wn inches. eit per lad. strain. WfeaAthoniI. fithoii. fathom. Cwy-t. Tons. 4 by 1 I 20 2t by 1 11......-...-..-......... 44 20 5 y 1-1 24 2 by - 13 -1-........... 52 23 5.-by 11 i 26 2 by 1 5....... _ 6 23 53- by 11 28 3 by - 16 2 by 10 64 28 6 by 1- 30 3 by 18 2 by - 11 72 32 7 3 by -- 20 - by - 12 80 36 81 by 2 40 3 by 11-16 22 | 2-1 by 13 88 40 8- by 2_ 4,) 4 y - 25 2- by 15 110 45 9 by2 1 a0 4-b 28 3 by - 16 112 50 92 by 2 by - 32 3- by - 18 128 56 10 by21 60. 4 - ) 34 3 by - 20 136 60 PRECAUTIOINS IN U SING WVIRE-ROPE. In winding with round wire rope upon conlical drums it is important to make sure that tle angle of inclination of the surface of the drum is not too great, as otherwise the coils of the rope are apt to slip off and cause serious accidents. Several fatal accidents have occurred in England from this cause. They are mentioned beyond in connection. with the notice of the various forms of safety cages. Mr. WVales, a government mining inspector, (Great Britain,) in his exanmination upon the cause of olne of the accidents referred to, said: " In his opinion, what most affected the proper and safe working of the spiral drum was the angle which the rope formed between the pulley over the shaft and certain portions of the drumn. In the present case the angle was fifteen degrees, and in his opinion the accident was principally due to that fact, and not to ansy defect in the rope, which was broken by the jerk caused by the rope falling from the drum. In conclusion he remarked that in erecting spiral drums care should be taken to have the rope at as easy an angle as possible, and in no case ought it to exceed frolm ten to eleven degrees." Professor Warrington Smlyth, of the British Royal School of Mines, in one of his lectures directs attention to the precautions necessary in the use of conical drmuns. He mentions the case of a very serious accident a few years ago, by which the lives of a number of men were sacrificed, simply, he believes, in consequence of the cage having been wound up at too great a velocity, and then allowed to slacken too suddenly, the result being that the laps got loose, some part slipped off; the rope went over the edge of the drum, and was snapped. Mr. Smyth then points out how this danger may be obviated by an ingenious contrivance of M. Lemielle, which consists of an endless rope passed down the shaft, and over a pulley at each extremity. The rope is thus kept constantly stretched out, and motion is communicated to it by a, direct-acting cylinder, which sets one of the pulleys in motion. It is found to be very dangerous to allow wire ropes to wind over any inequality or projection by which the wires are subjected to repeated bending back and forth. At the Cannock Chase Colliery, England. in 1867, the flat-wire cable suddenly snapped and precipitated eight men and boys to the bottom of the shaft, killing five. The inspector found that at the point of fracture the cable had been covered for about 8 -m 114 MECHANICAL APPLIANCES OF MINING. eighteen inches with hemp, which had become hard and solid, and formed a bolster or projection on both sides of the cable, three-fourths of an inch thick. The object of placing this hemp upon the cable was to show the engine man when the cage was opposite a certain drift, where it had to stop. In. passing to and fro over a pulley five feet in diamleter, and ucnder a drulm of the same diameter, the constant bending broke off the wires. This effect was probably gradual, since it appeared on examination that only twenty-five or twenty-six wires, one-seventh of the nunmber in the cable, were whole when the cable -finally parted. The covering also prevented the condition of the cable from being known, and it was believed that the breakling of the wires had been going on for three weeks or a mlonth before the accident. EXAMIPLES OF HOISTING WORKS ABROAD. As the depth of our imines increases the importance of improving our hoisting works becomes more and more apparent, and it will, therefore, be appropriate to notice iin detail some of the best specimens of hoisting engines now in use abroad, particularly at the collieries of Belgium, France, and Great Britain, where we find the -most perfect types and exhibitions of mining upon the most extended scale. At present onr best hoisting works are only approximations in construction and in magnitude to those abroad. The extent of our mines has not required us to carry our machinery to such a degree of perfection; but the day is not distant when for the Comlstock lode alone we shall not only have to avail ourselves of the fruits of experience in deep mining in foreign countries, but even to improve upon their most admirable and beautiful machines. There is nothing to prevent, indeed there is much to encourage, us to push our explorations of the Comstock lode to a depth of 3,000 feet or more; and for this purpose very powerful engines and hoisting apparatus will be required. The wise provision which should characterize all large undertakings, especially ill ininiag, requires us to take this subject into careful consideration. The engineers of BelgiumI and France have for some years past been discussing the best methods of carrying the exploitationL of their coal beds to a depth of at least 1,000 metres; and soiice of the opinions expressed upon this subject will be mentioned at the close of this division of the report, after somie details concernino' the existing conditions of hoisting have been given. There are two principal types of hoisting apparatus: the single elgine, acting upon the drum or bobbin-shaft, through the muedium of gearing, and the double engine, acting directly uponl the bobbin-shaft by cranks set at righlt angles with each other. Of these two types, the double direct-acting engines are preferred for large collieries, where rapi ( hoisting is essential. Professor Burat, in remlarkini-g upon the use of engines acting directly lupon the shaft of the winding drum, states substantially that w-helever the conlditions of hoisting do not require a greater force thamn 80 horse-,power, gearing should be used; andcl that the direct-acting engines withl two cylinders should actually exert at least 100 horse-power. Ift the cages are not required to move withl a velocity of at least four to five metres a second the gearing is evidently preferable to placilng tlhe winding drunis upon the craink-shaft. This opinion is confirmed by comparisons between the consumption of coal in hoisting works upon the two plans, wvhich are in f'avor of the machines with gearing. For hoisting with great rapidity, the direct-acting machines are the best, and are now generally used. PAGE 114 A (i, r!/_ / / VERTICAL HOISTING ENGINE-QUILLACQ'S CONS'TrRUCTION. HIOISTING MACHINERY AND APPARATUS. 115 Many establishments, alnd especially those of Haine-Saint Pierre, of Couillet, and of Seriang, in Belgium, and of Quillacq, at Anzin, have produced hoisting apparatus of this type which appear to leave little to be desired. Such machines are made either vertical or horizontal. In the fornmer the winding reels are raised high in the air, and the only advantage appears to be that the inclination of the cable is lessened, so that the angle it makes with the surface of the sheave is increased. A disadvantage is the instability of the machine, owing to the little breadth of foundation, and to its great height. The horizontal engines are much mlore firm and substantial. The accompanying illustration, printed upon a sepalrate sheet and inserted, (page 114 A,) represents an engine of Quillacq's construction of the vertical type. This figure is reduced by Bien's photo-relief process from one of the beautifully engraved plates in Burat's Atlas. It does not require much explanation-. One cylinder is shown in section with the piston at tile lower end. The brake-wheel is between the two bobbins. Thlle engineer stands upon an elevated platform on a level with the bobbin-shaft, and controls the valves by means of let ers. Three inches and three-eighths of aln inch upon this reduced drawing representsa distance of about five metres. In all of these modern engines a very great improvement has been made by the additio.n of a powerful brake, worked by steamln. Instead of the attendant exerting a large part of his strength upon the lever of a brake, it is now only necessary for him to open a valve by a hand lever, and thus admit steam to one side of a piston in a short cylinder, and the brlake is instantly applied with greater force than a man could possibly exert. For such powerful engines as are now in use, and worked as they are at a high rate of speed, a brake of this kind is indispensable. Mr. (Quillacq, constructing mllechanical engineer at Anzin, appears to have been a l)ioneer in the construction of large direct-acting doublehoisting elngines. He published a description of one of these engines in 185)9.7 The cylinders were each 0111.600 in diameter, and the pistons had a stroke of lm.800; bobbin-shaft 3r11.400 long' and 0111.290 in diamneter; two bobbins 6l'.()500 in diamleter; Stephenson slide nmotion; a steam brake, witll the cylinder 0m1m.350 in diamleter, drawing the two bramkes of woo(t powerfully upon the periphery of a wheel 31n.300 in diameter. Tlhis machine was l)rovided withl signal indicators, and apparatus fol arresting the motion of the enlgines and cages after the cages passed a certain point above the muouth of the sllaft. The whole machine, with feed-pulinmps and fisxtres, weighed 42,000 kilogralmues and cost less than 40,000 francs. The sameu constructor exhibited a very beautiful hoisting apparatus at the Paris Exposition in 1867. It was a double engine of about 200 horse-power. The cylinders were vertical and connected directly with the bobbin-shllaft, supported high in the air above the engines. Cylinders about 3 feet in diameter and 6 feet stroke. Link motion upon both. Bobbibns for flat wire or hemp cable, and 22 feet in diameter. Steamz brake, siglnal indicators, and apparatus for preventing overwinding were all included in this beautiful machine, for 38,000 francs. It appears from a bulletin that fromn 1856 to March, 1867, inclusive, the firm hmad supplied 67 machines of 7,012 horse-power in the aggregate, varying from 6 to 500 horse-power, the latter for pumping. in a machine exhibited by A. Aucldry, engineer of the establishment of AMr. F. Dorzee, near Mons, the bobbin-slhaft is placed below on a iAnnales des Mines. 116 MECHANICAL APPLIANCES OF MININING. level with the floor, and the cylinders rise vertically above it and act downward, instead of upward, as in the engine by Quillacq. The cylinders of this machine are 011".90 in diameter and the stroke m111.40. Five machines have been made upon this model at different times from 1853 to 1867, varying in capacity from 80 to 150 horse-power. A very beaLtiful machine of the direct-acting horizontal type was exhibited at Paris in 1867, by the establishlment of M. I. Schneider & Co., of Creuzot. Its strength, proportions, aind convenient arrangement of the various parts were admirable. The cylinders, 2111 long and 011.550 in diameter, are placed 5111.60 apart from centre to centre. The rods are connected directly with cranks of 1111, placed at right angles upon the opposite ends of a mlain shaft, 011'.3 in diameter, which carries the two bobbins and the friction-wheel, to which the brakes are applied by means of steaml, acting upon a piston in a small cylinder below the floor of the engine-roomn. The diameter of this wheel is 3m1, anid the length of each of the two w-ooden blocks wh-llich bear upon its periphery is 111.2. The diameter of the drumn of the bobbins is 212m.04, and total diacmleter along the arms is about 5111.5. The arms of the bobbins are of wood, and the extremities are not conllected by segmn-ents, as in many of the BIelgian and French machines. The length of the lever controlling tile brakes is 11n.9, the diameter of the cylinder 011.34, the length 0111.47. The engineer stands midway betweein the forward ends of the cylinders, with both the bobbins in full view, and by means of conveniently placed levers and hand-wheels controls the movelnents of the engine and the operation of the steam-brakle. The details of construction of a portionl of this engine are shown by the accompanying figur-le, reduced by the photo-relief process fiom the larger working clrawings pnublished in the Portefeuille des Iney'ietcrs, by the Messrs. Armengand. The figure gives a longitudinal elevation of the bobbin, the brake-wheel, and brakes, together with the steamc cylincler for operating the brake, and the levers by which the engineer controls the movements of the engine. The cylinders of the horizontall engines and their valves are not shown. B is the bobbin-shaft, carrying the bobbin with wooden spokes D D 1) and a ca.st-iron brake-wheel P P. The spokes, eight in nnllber, are not united by segmiental rims at their extremities, as in some machines, but are disconnected, the cable winding truly between the two opposite sets of slpokes without catclling upon their ends. These spokes are firmly bolted by their inner ends to a cast-iron socket plate, 2m.040 in. dianmeter. This plate and the brakewheel P P are securely keSed to the shaft B. An arm, IK 11'.90 in length, works loosely upon the shaft' B, and by means of the connecting rods J J controls the brake pieces I I, faced mith blocks of wood 1111.20 long, which fit into the hollow face of the brake-wheel P P. The brake-pieces, as will be seen, are supported in an upright position 3.230 apart by the prolongation of their frames to the foundation below, to which they are united by hinge joints. The und-ue separation of these brake-pieces is prevented by set screws placed behind each, and their approximation and pressure upon the brake-wheel is controlled by means of the rod IK, extending froml the end of the arm K to the steam cylinder AI. By means of the hand-lever O N steam can be instantly admitted to one side or the other of the piston in MI, and thus operate the brakes with great force. The engineer stands upon a platfornm just above the steam cylinder 3l, and controls the link-motion by means of the horizontal hand-wheel RI. The dimensions and distances of the mnost imlportant parts are indicated upon the figure in metres andl in fractions of a metre. I ~ ~ ~ ~ ~ \ 41/I -:: loi -i -~ ___'._x__ —-'.~____ b.-:i.: —_ —_ - _~ ~~~~~~~~~~~_ _ - j Ui J-~ ~ ~~~~~~~~~~~~~. i.,:?~l.J~' ~'f.. /III, I,/ /~~~~~~~~~~~~~, 7/~ ~~~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ jy - \ jK/n. The Crenzot Direct-acting 1-Jorizoiltal Winding rEnin s b~~~~~~~~~~~~~~~~~ o o~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.-'~-'-' "." c s,i~~~~~~~~~~~~~~~~~~~~~~~~~~~~~r~:,,! ~: ""~':'"">'~"~'~'~~~ The Creuzot Direct-acting Horizonta~IlWindnnin —scioa e l evation. 118 MECHANICAL APPLIANCES OF MINING. At the mines of Sainte-Barbe, at Bezenet, the extraction from a depth of 161iG to 18511 is effected by a double horizontal engine, the two cylinders being connected directly with the bobbin-shaft. The pistons are Om.7 in diameter, and 1111.9 stroke. The drum or center of the )bobbins is 3111.5 in diameter, and the mnininmunl radius of winding space is therefore lm.75 for one of the bobbins, and greater for the other, which winds from the greatest depth. The brake is controlled by a separate steamcylinder. A contrivance for preventing accidents in case of over-winding closes the throttle-valve of the engine and puts on the steam-brake. This apparatus once prevented a very serious accident, by arresting the cage before it reached the sheaves. The cages weigh 1,900 kilogrammes, (1,600k iron, and 300k of wood,) and are made to receive six cars. Four sheet-iron cars weigh, when empty, 960 kilogrammes, and contain 20 hectolitres of coal, weighing 16,00 kilogralnmes. The dead weight is therefore 1,900 + 960 - 2,860 kilogrammes. in ordinary working the time of ascension of the cage and load is 27 seconds. The landing and returning the cars require a meall of 18 seconds; total time, 45 seconds. Practically, they take out four cars a mlinute, or 240 cars per hour, and 2,400 in ten hours of effective work. Experience has shown that they can extract reg ularly 2,000 cars, containing 10,000 hectolitres, in ten hours. The two cables are adjusted to hoist from two levels, 24m1 apart. The drainage is effected with a single trip, and occupies only a part of the night. The quantity of water extracted varies between 6,000 and 10,000 hectolitres. The cables are 23 centimetres wide and 42 millimetres thick, made of iron wire covered with hemp." As an example of the dimensions and cost of mnodern hoisting engines in Saxony, the following from the notes of WV. Fairley, mining engineer ancl surveyor, is interesting: The mine is at Zwickan, the Briickenberg colliery, 444 English fathoms in depth. The shaft is rectangular in section, 28 feet long by 8 feet broad; one-half of it is used for winding with two cages, the other half for a ladder-shaft and return air. The ventilation is effected by a Guibal's ventilator, measuring 7111 by 31l11 and driven by a 50-horse engine. The hoisting works consist of a palr of horizontal engines, built at the WVilhelm's Hiitte, Sprottan, Schleswig, at a cost of ~2,850. The cylinders are 42 incles diameter, stroke 8 feet, wincling-drum for flat ropes 12 feet diameter, ropes tapered. The time required for hoisting from the 444 fathoml level is two and a half iiinutes, a speed of about 20 feet, on an average, per second. Tlle cage carries two wagons of 10 hundred-weight side by side, and is furnished with a safety apparatus for its arrest in case of the breakage of' tlhe rope. GENERAL OBSERVATIONS PON I-OISTI1NG: ENGiNEIS. In all these engines for collieries, where coal is so abu-ndant and cheap, very little attention has been given to the question of economy of fiuel, a very important one for regions like that of the Comstock? d(lependent upon wood brought from a distance at considerable expense. Condensing- engines are too complex for hoistil ng purposes, whIere it is so often necessary to reverse the motion; and the only dlirection ill which it appears possible to effect a great saving of ste111n is i worlkillo it expansively as inmuch as possible by the use of suitable cu(t-ofif valves. Tlhe Exposition of 1867 contained a( double engine on W\oolfT's plsan, nd(l collnsequently withlr tol cylinders, which coull be ulsed a-dvanta1'eously as a' Front dacl:t supplied bly Mhl. Lan and LBaur to ItProtssor: Burat7, 1'57. HOISTING MACHINERY AND APPARATUS. 119 hoisting-engine, if the necessary apparatus for changing the direction of rotation were supplied. It is an interesting fact that English colliery, owners find it for their advantage to contract for their hoisting-engin es'and machinery with the French constructor Quillacq, at Anzin. This eminent maker astonished the British members of the international jury by the statement that he had supplied both pumping and winding engines to an important Newcastle colliery. It is admitted by the British reporter upon that class in the exposition, that the order was given to the French manufacturer simply in consequence of his lower price and better finish, as compared with the tenders from English houses; and he observes:;" Here we have, then, one of our Newcastle imLines actually working by means of French-made machinery, fairly brought in, by open competition, to the midst of'our machine shops and foundries; and when we look at the inland position of Anzin, and the unquestionable disadvantages which have to be combatted in a district where coal and iron are com!paratively dear, I cannot but think these results redound to the credit of French engineering, and inculcate on ourselves an important lesson." Opinions upon the relative value of the two methods of mounting hoisting works, whether they should be vertical or horizontal, are still divided. The English generally prefer the vertical form. There is not only the advantage in regard to the inclination of the cables upon the pulleys, a very considerable advantage when one of the cables is wound on the lower surface of the bobbin, but the engineer can be placed much nearer to the landinig-place of the cages, and thus, having their movements directly under his eye, will avoid many accidents that would otherwise happen, notwithstanding any system of signals. It has been supposed that the vertical machines *are much more costly than the horizontal; but AM. Parent, director of the Anzin works, who has used both, holds an opposite opinion. There is so much doubt in regard to this matter that the Anzin company, having two shafts to provide with hoisting works, decided, in 1868, to place a vertical engine over one shaft, (IHavelnuy,) and a horizontal one over the other, (St. Mark.) The question of the relative advantages is still undecided; but it is agreed that in all cases it is best to place the engineer as near to the landing of the cages as possible; and to secure this, the position of the horizontal engine has been changed. The engine has been turned end for endl, so as to place the cylinders toward the shaft, and bring the engineer within five or six metres of-it. In order further to illustrate the general form of large hoisting works abroad, one of the engraved plates in Burat's Atlas has been reduced, and is printed u1)on a separate sheet to accompany this chapter. It represents the construction at the colliery of Bezenet, and shows not only the large derrick supporting the great pulleys over the shaft, but the two-story iron cages, the cars, and the arrangemeent for automatic lowering of the loaded cars to a track upon the general level while the empty cars are hoisted. The engine-house and engine, with the large bobbin for fiat cable is seen at the right-hand end of the plate. A rod with an ram l)rojecting over the cage is so arranged as to stop the engine in case of over-windin The boilers are set outside of the building upon the extreme righllt. IIOISTING FRO-M GREAT DEPTIIS. The Academy of Sciences of Brussels in 1856 proposed the subjoined question for discussion, and the minister of public works offered a special prize for a satisfactory answer: [Transltation.] " Indicate a 120 MECHANICAL APPLIANCES OF MINING. complete plracticable method for extending the exploitation of collieries to a depth of at least 1,000 metres, without sensibly increasing the cost of working beyond that in Belgium at the present time." Among the most renmarkable of the memoirs presented was that of AM. Devillez, professor of mechanics at the school of mines of Hainault. He concludes that, without any new invention, but with a judicious use of the best meaims of exploitation then employedl, it was quite possible to succeed in working at such great depths. He proposes to use, instead of hemp, flat cables of iron wire, weighing, on an average, 7k.33 per running metre, or a total for each of 733 kilogrammes. Cables of the same lengthl of hemp would weigh more than 9,000 kilogrammes. With such wire cables, he could raise, at a mean velocity of six metres per s.econd eight wagons containing together 2,700 kilogrammes of coal. The dead-weight of the cage and wagons would reach 2,150 kilogrammnes. The whole could be brought to the surface in three or foulr minutes, and he thinkls that a 200 horse-power engine would be sufficient for the service. The initial radius of the bobbins, according to calculation, should be 0m.72 for tapering cables of iron wire and 11m.00 for those made of hemp. Another mnethod proposed for hoisting froml great depths, and already put to a test in practice. deserves mention. It is the contrivance of the ellgineer, M. lehu, and was experimented with in one of the shafts at Anzin. It consists of two vertical oscillating rods moving up and down in the shaft, as in the man engine, and attached to the extremities of a hydraulic balance. One rod raised the full wagons, and the other carried down the empty wagons. But after being tried successively at the mines of Anzin and of Bonchamp it has been abandoned. TURNING OR STAPRTINTG GEAR. An apparatus has recently been constructed andcl applied in England for rendering uniform the driving power of single cylinder steam-engines used for winding or other purposes. It is well known that the driving power of single engines is far firom being uniform throughout the revolutions of the crank. -At the end of the strolke dead-centers exist, anld there is no tangential pressure a aall; and from these points the!pressure upon the crank pin in the clirection of its motion gradually reaches a maximum at about the middle part of the stroke, and as gradually diminishes to nothing. The object of the apparatus, which the inventors- call " turning-gear," is to enable single engines to be started, reversed, or to work with the facility and regularity of double engines, with their cranks at right angles to each other. The advantages claimed for the apparatus over double engines are its great cheapness and the possibility of its application to existing engines as well as to new ones. It consists of a small supplemental oscillating steam cylinder, placed below and a little back of the main crank, and connected with it by the middle of a jointed connecting rod, one end of -which turns upon a fixed bearing in the foundation. A toggle-joint is thus formued. and the piston connects at the joint. This toggle is so pltaced as to operate tangentiallly uponi the crank when near its dead-points. The inventor claims that by such means the engine possesses equal driving power during every part of the crankl s revolution, so that upon the dead-centers all the work is done by the turning gear, but during the rest of the revolution it is done by the crank alone, or in combination with the turning gear. With this transfer of pressure fiomn one part of the revolution to * WTilliaim Macgeorge, London, and ArthIur Rigg,. Chester. HOISTING MACHINERY AND APPARATUS. 121 another no steam is consumied; there is no loss of power, except the mere friction of the apparatus; neither is there any direct gain. He says: For winding purposes at collieries or miles, single engines are objectionable, although frequently used, and doduble engines are preferable on account of their haldi: ness and safety from overwtininng acnd the uniformity of their power at e-very part of their revolution. Now, as this turning gear oives to single engines all the advantages belonging to double engines, there is manifestly a savinll in first cost, and to this mLust be added less expensive foundlations and a smaller engine-house. It is equally applicable wherever the use of a fly-wheel is inconvenient, and ias been,applied to a coimpound marine screw engine of 100-horse power. With its use there is. not the slightest hesitation or uncertainty in starting or reversing, anud the engine can either revolve at full speed or be made to crawl slowly round, with the regula[rity of clock-work. It would be almost superfluous to point out the peculiar advantages of this latter capability in doing pit work at collieries. The inventor claims to acconmplish the same result for engines which revolve in one direction only, by placing a large double cam upon the end of the crank shaft, in such a position with respect to the position of the crank that it is acteld upon by a roller forming the heaed of a short piston, working in a cylinder directly under the shaft. This is a very simple and cheap forul and can be applied to any engine. Drawings of this apparatus accompainy the Colliery GIuardian for Janiuary 28, 1870. CHAPTER X. SAFETY-CATCHES, OR PARACHUTES. The great depths to which mining operations are now carried; the increased rapicity of movement of the ca.ges, (often as great as thirty and forty feet; in a secon(l,) and the paramount obligation to protect the lives of the miners who often ascend and descenld by the cages, has led to the adoption of a variety of contrivances for arresting the fall of cages il the eveant of the breakage of the cables by which they are suspended. Such colltrivances are known as paccrachutes or safety catches. The goreat velocity of hoisting requires the cages to be guided inl the shafts by vertical tracks, which are commllonly constructed of wood, though of late they are being replaced by iron and steel; these tracks, called guides, being continuous andcl equidistant along the path of the cage, furnish a foundation upon which the various parachutes canl act to sustain the cage in the event of breakage. A large 1 number of patents relating to this important and indispeinsable apparatus have been taklen out, but it may be said that there are only three types, and that these originate from the saume principlelevers drawnr1 up aLnd away from the guide by the traction of the cable, and in an opposite direction by the tension of a spring which tends to throw the levers outward upon the guides, so as to press upon or into them with a force capable of stopping the fall of the cage in. case of the rupture of the cable. One of the forms of safety catch now in use in the Savage silver mine upon the Comstock- lode has already been described and shown by a figure in connection with the description of the ordinary form of cage. This description and figures will be founcd upon pages 576, and 571. In 1845 -M. Machecourt published a description of a parachute which he had applied to the cages in the shaft of a coal imine at Decize. This parachute consisted of two pointed bars or arms of iron crossed and 122 MECHANICAL APPLIANCES OF MINING. turning upon a rod like the two blades of a pair of shears. While the cage remained suspended by the cable the points of these arms were drawn inwardl, away from the sides of the shaft, but in the event of the rupture of the cable, the arms were thrown outward and downward by springs. and penetrating the timbers of the shaft, held the cage suspended. In 1849 AM. Fontaine, of Anzin;' constructed a parachute for the Tinchon shaft upon this principle, but in a better form, and at the time of the publication of Professor Burat's 1Materiel des Houilleres, in 1861, the form nost in favor and indeed the only form with which sufficient experience had been acquired to justify a recommendation of its general use, was the Fontaine parachute, then in use in more than fifty shafts in France and Belgium. It is considered as having originated with tlhe Anzin company, and owes its introduction and success to the careful attention with which all its details were studied and modified by long experience. All parachutes combined and constructed on this principle have given satisfactory results, and it may be said that, if the security obtained is not complete and absolute, they have, nevertheless, rendered such great services that their application has become a question of humanity, which cannot be ignored. The following figures will speak in a stronger and more peremptory manner than any description to persuade miners and engineers to adopt parachutes in their mines. At the mines of Anzin, from 1851 to 1859, in fourteen shafts supplied with parachutes, twenty-nine cable ruptures occurred, and the parachutes saved the lives of one hundred and fifty men. What can be more eloquent and more persuasive than this fact? At the mines of Blanzy the experience has been similar, and it is probable that if an account had been taken of all the accidents by the rupture of cables in Europe since parachutes came into use, it would show that the men who have been saved from. certain death by parachutes can be nimbered by thousands. In order that a parachute should act well, it is necessary that the strength of the spring should be equal to 150 kilogramlmes, (300 polunds,) and then the weight of the cage makes the rest; and the heavier that weight the more energetic is the grasp on the guides. The three types are1. The parachute with claws, which acts by a pressure exerted upon the guides tending to penetrate them longitudinally. 2. The parachute with eccentrics, which acts by a pressure exerted laterally on the sides of the guides, and perpendicularly to the plane which passes through both of their axes. 3. The wedge parachute, which acts by means of a set of metallic jaws taking hold of the guide, which is made wedge-shaped. This parachute gives a lateral pressure exercised upon the faces of each guide, and perpendicularly to the plane of the parachute. These several types will be considered one after the other. FONTAINE'S CLAnW PARACHUTE. The annexed figure represents Fontaine's parachute with claws. It is the oldest, and was constructed and put in use at the mines of Anzin, and may be said to have originated with,this company, At first this parachute was supplied with only one spring, but two are now used, as shown by the drawing. It was the type exhibited upon the two-story cage sent by the company of Anzin to the Paris Exposition, in 1867. IOISTING MACHINERY AND APPARATUS. 123 The two stout diagonally placed arrms in the drawing are armed with sharp steel points, and are so placed in the frame of the head of the cage that when it is suspended in the shaft by the cable, these claws 0 Q Guide. Fontaine's Parachute. Guide. are drawn up so as not to touch the guides. Two strong, spiral springs, replaced in somle parachutes by steel elliptic springs, are placed below, and in the event of the breaking of the cable they draw down the upper ends of the claws, and the lower and steel-armed ends are forcedt- outward into contact with the wooden guides, penetrating and sometimes splitting them. The cage is thus arrested in its fall, and is sustained entirely by the wedging of these claws against the guides and timbers of the shaft. Each claw can work independently, the double hook at the top permitting either one or both to be thrown out together or to different distances, so that inequalities in the size of the shaft or of the distance between the guides may not prevent a perfect contact of both arms. The projections beyond the guides upon each side are intended to represent a part of the framework at a point where the guides are perforated for the reception of a bolt intended to prevent the cage from being hoisted prematurely. This is a contrivance introduced by the engineer Cabany, and is placed at the bottom of the shaft. The Fontaine parachute has given satisfactory results in saving the lives of Ien, but the claws injure or destroy the guides. It also necessitates the use of very heavy timbers for the guides and their supports, inasmuch as presstire from the claws is exerted in one direction, and if the guides should yield or bend outward the effect would be lost. The first cost of such heavy guides a-nd timberilng is very gre at, and any accident, by (lestroying a portion of the guides, requires a great expenditure for repairs. 124 MECHANICAL APPLIANCES OF MINING. AUDEMIAR'S PARACHUTE. In order to avoid these difficulties other constructions have been devised. One by Mr. Aucldemar, engineer in the servrice of the mining company at Blanzy, is shown by the annexed figures. It consists of four 1 1 Andemar's Parachlte. eccentric wedges, two on each side, and placed on opposite sides of the guides; the release of the springs by the breaking of the cable causes these eccentrics to turn and to powerfully squeeze the guides and thus stop the descent of the cage. This parachute is as certain in its action as that of Fontaine, and does not split the guides. The guides and the framework may also be made nmuch lighter, for there is no outward thrust or pressure tending to bend or break the tinmber. It will be noted that the action of the c dog-clamp" safety catch upon the cage used in:Nevada (see p. 56) is similar to that of this eccentric catch. The sides not the face of the guide are acted on in both cases. The spiral springs used by Mr. Acldemar are made of steel wire 0111.01 in diameter. When filly expanded they are On.39 long, (nearly 10 inches,) and they may be condensed to a) length of 0111.25: but in order to preserve their fill elasticity the springs are condensedc from 0111.09 to 0m.11 only. A compression of 0111.09 is sufficient, and this gives a resistance of 180 kilograinmes, (about 360 pounds.) Motion is communicated from the springs to the eccentrics by means of arms and levers, as shown in the figures. The first figure shows the position of these arms and the eccentrics when the cage is suspended by the cable; and the second their position when the strain from the cablle is released and the springs are expanded. The spiral springs are contained in cylin HOISTING MACHINERY AND APPARATUS. 125 drical boxes, one part sliding over the other. One of these boxes and the spring are shown in section in the second figure. Aundenar's Parachute-section showing one of the springs. The experience of more than fourteen years with parachutes of this type has been most satisfactory. In this construction the springs are kept in constant use by being compressed and they thus relieve the shock when the cage is started. MICHAT'S PARACHUTE. A variety of the same type 1as the Blanzy construction, 0 designed by AMr. Miclhat, is shown with sufficient clearness by the appended figure, and a description is ulnneces- i sary. It is evident that it I does not differ essentially (,.[, from the parachute just de- -' scribed. BRAUNE'S PARACIHUTE. __ Q This is a third variety of the same type, but it differs from the others by its extreme simplicity and the nature of the spring. This form originated with Mr. Braune, chief engineer of the mines of the Michat's Parachute. 126 MECHANICAL APPLIANCES OF'MINING. Vieille Miontagne Company. A simple India-rubber band spring is all that is used to draw the eccentrics in upon the guides. It is said to have given satisfaction for a period of three years or mlore; but it is doubtful if a spring of this nature can long remain active and reliable w, hen under constant tension. PARACHUTE WITI-I VEDGES. The third tyle of parachute is known as INyst's, and is constructed to. act like a wedge. (0 It has arms like a parachute with claws, but B S. /g the latter are replaced by a metallic jaw, in the form of a hollow wedge, fitting to the form of! 1'?.li t:,9 J"'X the guide, which is nmade wedge-shaped. When I,,;.I the parachute with the cage is sustained by the 0.S/'NG cable, the jaw moves along the guide without touching it; but if a rupture occurs, it then presses upon the guide and wedges -powerfully, so as to arrest the descent of the cage within a Braune's Parachute. distance of only 0m.25 or 0111.30. The action is thus very prompt, but it is so gradual that there is no perceptible shock. This construction does not injure the guides, and it has the advantage over the parachutes of the second type that iron guides may be used, the reduced size of which is nmuch less cumbersome in shafts than heavy timbers. It, however, requires the guides to be made with great accuracy, and uniform in size andc angle of the wedge, and the difficulty of obtaining them has prevented this parachute from conling into general use. TIHE VALUE OF SAFETY-CATCHIES IN SAVING LIFE. Althouglh the construction of parachutes has not by any mleans reached perfectionu, there being some cifficnlties attending- their use, they have renderedl the greatest service in mining operations, repeatedly preventing great losses of life and property; and llo excuse can be received for allowing a single mining- cage to be without one wherever iliners are permitted to ascend anld (lescenl in it. Accidents from the unaccountable breaking of the strongest cables are not infrequent; and when it is well known to mining engineers that pararnchutes of the proper construction have repeatedly been the means of saving life, it is strange that there should be any hesitation in adopting them. Even while writin g this chapter the report of a recent accidenlt (January, 1870) at one of the shafts of the DIowlais Comlpany has been handed to me, and a condensed accounlt of it is inserted as appropriate in tlis colnnection: A fatal accident happened at the Deep Pit, Vochrihiw, the property of the Dowlais Company, on Saturday afternoon,l about 5 o'clock, by which five persons lost their lives. It appears five men were ascending the pit, and when within 27 yar'ds of the top the rope broke and the poor fellows were precipitated to the bottoml, a depth of 500 yards. The bodies were smashed to pieces, and death imust have been instantaneons. This is the sa.me pit where a similar accident occurred a. nionlth ago, wh11-n two men lost their lives. It harppened in the slIle lanner as tihe one on Saturday, and apparently fromn the saole canse. The Vochrhiw pit is a very large colliery, employing about 600 hands. It is 400 yards deep, and is worked by two shafts, Nos. 1 and!2; the No. 2 being the shaft, generally used for the passage up and. down of men and horses, the other shaft being reserved for inineral alone. But, as. these accidents show, the rule adopted by the company has not been kept by their leln HOISTING MACHINERY AND APPARATUS. 127 The pits are worked by spiral draum-an invention which has called forth on several occasions the approval of the government inspector, as they enable tile engines to raise heavy weights as well as the cage and rope of a pit 400 yards deep with ease, and without any extra power. But then safel;y depends chiefly, we may say, upon the angle formed between the rope and the pulley above the shaft with certain portions of thile drumn. It ought not to exceed tell or eleven degrees, though the anglle at the time of the first accident was als much as fifteen degrees, and to that Mr. Wales ascribed the accident, as it prodclced tile overlap of coil which led to the accident. Onl that occasion the coil overlapped when the umen were two huilcndred and fifty yards from the bottonm, and the jerk caised by its falling into its place snapped the rope and precipitated the cage to the bottom. Onl Saturday night the No. 2 pit was busy between 6 and 7 o'clock in bringing out the colliers, and there were then at the bottom of the No. 1 shaft four hitchers an:d the oyerman of the pit. In their anxiety to get out without walking through the workings to the other shaft,, it is conjectured the whole of them got into the cage of No. 1 shaft, and signaled to the banksman to set the enloine inl motion. The engine started, andcl the cage was brought to within 27 yards of the bank when the fatal overlap of coil againu occurred, and the jerk which followed snapped the rope and brought about the drceadfl catastrophe. Here we have the particulars of two fatal accidents fiom tlhe same cause, and in the same mine, within about a month; and it does not appear that any effort was made after the first accident to prevent a second, nor does it appear that the cage in either case was provided with aly forlm of safety-catch. At the inquest after the first accident at Dowlais, it was testified by the engineer's foreman that a similar accident, but to an empty cage, had previously occurred in the same pit. In the Colliery Guardiau of September 16, 1869, there is an account of a slhockinlg accident which occurred at the Kirkless colliery, Wigan. The men were leavinig the pit early il the afternoon, and while eight of the nrumber were being drawn. to the surface the wire rope on one side of the drum sliplped as it was being wound on, thle loose coils fell over the flange at tihe end, became entangled in thle eccentrics at the side, and, weakened by the chaffing which it had received by being pressed between those revolving parts, parted by the sudden jerkl given by thle cage as it took out the slack in descending. The cage, containing eight persons, fell, of course, to the bottom of the shaft, a distance of 2 70 yards, and several men were instantly dashed to pieces. At the inquest upon the bodies, the government inspector said the dr1ml was rather too conical, and, in his opinion, some sliglit deflection of the pulley had caused the rope to coil back, and so led to the slip. A drum of that shape required the nicest nianagenlent, anl care in- keeping the pulleys straight. Here is alnother accou-nt, of an accident in Pennsylvania, reportecl in the daily papers; since this chapter was written: S1i1wEANnDO1A CITy-, SCHUYLKILL COUNTY [, ael'ch 29, 1870. A terrible accident occurred at the coal minlle of Richard Hecksher, a few miles from this place, at lan early hour this morning. While four men were clescendlin the shllft to commence the day's work, the rope broke, precil)itating thell to the bottom, over 60 feet. All were instantly killed. There appears to be great opposition on the part of English miners to the introduction of any forlm of the parachute. Iin some observations by a " lniner," upon the above-described accidents, the following passages occur: Are any of the safety-cag.es, which have froml time to time beell invented, really suitable and efficient; arid, if so, why are they Lnot adopted? Now, the fact is, a really suitable and efficient saftety-ca ge has still to be discovered; all that have yet been brought forward being objectionable for one reason or anlotller. That many of thle contrivances a:re hiohly ingenious canlnot be questioned, but in practice they have, withou-t exceptionl, beell found w-ainting; either they are too firagile, damage the guides, or require such continumal attention to keep them in order that it is dangerous to place relialce upon tllem; and it is.generally felt that if reliance be placed upon an apparatnus of thie failure of mwhich there is a remlote probability, it is better to depend upon the rope alone. The various safety-cages which lla;ve been proposedl are readily refera 128 MECHANICAL.APPLIANCES OF MINING. ble to two classes, and the great question is, which class is the best? OIle class of catch —for really the safety-caoe is merely a safety-catch applied to air ordiinalry cageis so arranged that it is brouight into plaly ait the end of each journey np and down tihe pit, the object being to prevent the apparatus becoming worthless from disuse. The idea is doubtless good, but the objection is, that the.wear aLnd tear are so great that the apparatus is worn out and useless before it is required to ayert calamity, the consequence being that whenl the accidelnt'happeins it is fatal, as usual. In the othller class the apparatus is ilever brought into play until the accident occurs, the object being to avoid the danlngers inseparable froml tlle former; the wear and tear are, of course, prevented, but frequently, when the accident happens, it is found that the whole concern has become fixed from disuse. Perhaps the only arrangements not open to these objections are those soimewhat like Aytoun's and Nyst's, each of xwhich depeLnds for its safety upon the nmere cllanire of position of a metal fork, or its equialent, so as to become fixed againlst the guide-rods. Both of these catches are extemnely silnmple, have no springs, or similar contrivanices to get out of order, andl would ol t cost mllore than'r few shillings to apply them. It has been said that they knock the guide-rods to pieces when they are brorught into iaction, but as the daimage can only occur wriheln in naccideilt h11s lhappened,.nd a calamity beell averted, surely this should not plrevent their adloltionl. As neither are protected by patent, every colliery proprietor call have them imallde by his own simith. It is a very common opinion apIong plractical inni tira thlt tlise of saf ety l.ppanratus begets carelessness on tile part of those engaged about tlle shaft, bult ierhlaps the ground for this comiplaint is miore apilparent than real, aind as the cage is withLout question as safe with' the apparatLus as without it, it nlight be dlesirable to accept reliance on the catch as imore than equal to tile dilllinished attention of thle r-len. The last paragraph of this extract is a good answer to the general cdrift of the opinion expressed by the British jury upon the safetty-cages exhlbited in the International Exhibition of 1862: " Thle jury gave careful attention to all the varieties of this applaratus, and were strongly impressed witll the mlerits of several of them, and with the desirableness of enlistingl in this cause the interest of the intelligent -mlechanician. But they share in the repugnance of colliery viewers to trust to the action of a spring on which most of them depend, and which, of whatever substatnce it is made, is sure by degrees to lose its elasticity, and is thus liable, unless frequently looled after, to fail at the moment when required. They are also aware tllat a great inconvenience, not to say danger, has been introduced by all those hitherto employed, in consequence of the apparatus l)eing brought into play by a plunge durinlg the rap)id descent of the cage, allnd that hence several of these inventions, after being fairly tried for one, two, or three years, have been ultimately removed. SNor is it too imLuch to say, although an insufficient argument if taklen alone, that the employment of this apparatus has a; tendency to make I)eople careless about the exam-lination and renewal of ropes.?'" In -view of the very satisfactory experience with parachutes in the large colleries upon the continentl, and above all, the thet that they have repeatedly saved many lives, thle writer trusts that their use will not be neglected in the mines of the West; and it is gratifVing to know that they are now attached to most of the cages in tle mines upon the Comistock lode. It would not be difficult to collect many accounts of fatal accidents in those mines, which probably could have beent avoided it properly constructed parachutes had beeil used. There is one remarkable c;se on record, showing the usefiuiless of another precautionl though it providentially failed to be another of the terrible warnings which call for the use of parachutes: A cage in tile Hale and Norcross Mline was precipitatedL to the fifth level, a distance of 230 feet, without breaking any bones of a 1nan who was upon it. The entire steel-wire cable fell down the shaft a.nd coiled upon the roof of the cage. Thle roof protected the miner from being crushed by the cable; and this shows the importance Reports of tile British jury Exllibition of 1862. HOISTING MACHINERY AND APPARATUS. 129 of placing a hood upon every cage in which miners are conveyed. The form of such a hood is of some consequence. There is a case on record in England of a miner, standing in a drift near the bottom of a shaftt being killed by a pebble which, falling from the surface upon the domeshaped roof of the cage, glanced off and struck him. Examples are not wanting of the utility of safety attachments to cages in mines upon the Comstock lode. In February, 1869, a steel-wire cable was broken in the Imperial-Empire shaft; but, owing to the safety attachment to the cage, no other damage was done. The Mining and Scientific Press of San Francisco, in September, 1865, reports that in one of the mines (the Sierra Nevada, it was believed) a safety cage, heaAvily laden with ore, had nearly reached the top of the shaft when the rope parted. The safety catch prevented a free fall, but the load was so heavy that the descent of the cage was not completely checked, andl it went to the bottom so slowly tlhat not a bolt or timber was broken. Frequent experiments made in the Comstock mines, by cutting the cable above a loaded cage suspended in the shaft, have proved the efficiency of the parachute. SAFETY HOOKS. With the modern powerful and rapidly winding engines, the least inattention on the part of the engineer as the cage nears the surface may permit it to ascend to the sheaves and produce great destruction. Numerous and fatal accidents from this cause are reported in the mining journals. Even while this report is printing, accounts of an accident at a colliery near 1Wigan * show the fearful results of over-winding, and the importance of some means of prevention. Various contrivances have been proposed and adopted to prevent this over-winding. Safetyh ooks, which open and leave the cage free to rest upon spring-catches. below it, are the most commonu; but it would seem that the best contrivance of all is the very simple one of placing one arm of a lever, a bent bar of iron, in the path of the cage, so that if it passes that point the supply of steam to the engine is shut off, and the valve of the steamn-brake is opened. Thus, by one blow upon this bent lever, the engine is stopped, the brakes are applied, and the windining of course ceases. This has been rendered possible by the additiomn of the powerful brakes operated by steam. Among the many forms of detaching-hooks which have been pro%Effixtrhlaordiary colliery aceideet tear I7Vigan.-Shortly before 10 o'clock on Tuesday -night a shocking colliery accident, by which one man was killed and four others received iinjuries more or less serious, occurred at Messrs. Blundell's No. 1 Sinking Pit, situated in the township of Pemberton, near Wigan. The shaft has been in course of construntion for nearly a couple of years; it is of mlore than the ordinary diameter, and the work has hitherto progressed without serious impediment. The men employed work in eighthour " shifts," and at a quarter to 10 on Tuesday preparations were made for bringing one of these working parties to bank. Four men entered the hoppett to ascend, and they were drawn to the surface; but here the engineer, Thomlas Ackers, found hle was unable to reverse the engine or to apply the brake, owing -to some derangement of the machinery. The consequence was that the hoppett was drawn at great speed over the pulley, and then throngh the roof of the engine-house into the building itself, which was a perfect wreck in a few seconds. Two of the men, fearing, from the speed at which they approached the surface, that they were about to be " pulleyed," made a desperate leap for life as they reached the bank, and one of them escaped, COpllparatively speaking, unlinjured, while the other, fearfiully shaken, was falling into the pitshaft, when he was saved by the banlksmian. A third, named Butler, kept his place until the hoppett arrived at the engine-house, when he was flung a distance of forty yards over the building, and he, too, escaped wvithl his life; but the fourth was. not so fortunate, as lie was dragged into the house and killed instantaneously. The engine tender was also seriously hurt by the falling d6bris.-Eroim the Colliery Guardiatn, March 11 1870. 130 MECHANICAL APPLIANCES OF MINING. posed, there is one which is advertised in the English journals as extensively used in collieries. Its construction will be seen from the figure. It consists of two plates, placed face to face, and turning upon a central bolt. It forms a part (a link) of the winding cable or chain, and is so made that if drawn up through )A a hole in a cross-beam, bushed with a heavy cast iron lining, E, E, the expanded wedge-shaped sides, H, H. are pressed together, by contact with E, E, so as to liberate the bolts of the cable, A and B, at D and D. At the same time a square shoulder a upon each plate of the link catches upon the upper __edge of the hole, and sustains the weight of the: cage. This is said to be extensively used. A form 0< _of safety-hook used in Nevada is shown upon a > previous page, in the drawing of the cage now in use upon the Comstock lode. The safety-hook by S. Bailey, proposed in 1860, B consists of a fixed ring between the guides over H the shaft, through which the cable passes. WVhen the cage is drawn up too far this ring acts upon two projecting arms, which detach the cable, while, at same time, hooks are thrown outward over the ring, and by these the cage or kibble remains susSafety Detaching-hook. pended.* SIGNAL INDICATORS. Carefully made indicators are now attached to winding engines, in such a manner that the position of the cage in the shaft is shown to the engineer by the movement of an index or pointer along a horizontal scale, and as the cage approaches the top a bell is sounded once or twice, and if it ascends too far the apparatus shuts off the steam and stops the engine. CHAPTER XL RAISING WATER. It is un-necessary here to do more than mention the very common method of raising water from mines of small extent by means of the tub and windlass, precisely as ore is raised, or by a barrel fitted with a large valve in the bottom, which opens and allows the barrel to fill automatically when it reaches the sump. This method was in use at the Amador mine to a depth of at least eleven hundred feet, the buckets being of iron and cylindrical, like the tubs for ore, and sliding like them upon the guides along the inclined shaft. Guided skips fitted with valves are similarly used. In Virginia City, Nevada, along the Comstock lode, many of the shafts were kept drained by these simple means, and the only apparatus worthy of further note was the method of delivery of the water into movable launders. When the barrel of water reached the surface, a launder, running upon rails laid on each side of the shaft, was pushed under it. The barrel was then allowed to descend and rest upon cross-bars, and, by raising the valve, the water was discharged into the head of * Joiur. Mining, 1860, and Rev. Universelle, May and June, 1860, p. 511. RAISING WATER FROM MINES. 131 the launder and conveyed away without the necessity ofmoving the barrel out of the line of the shaft. Cylindrical watertubs have been used to a considerable extent in the French collieries. They are usually made with a capacity of 20 hecto- litres, equal to five:j.?: hundred and twenty-eight gallons, and weigh about 700 kilogrammes. The water enters by a large valve at the bottom, and is discharged through a side orifice. Witlh this form of appa-' - ratus for hoisting water, it is neces- " sary, in order to avoid loss of time to provide guides in the shaft, so that the tub may be drawn up and lowered rapidly. It has also been' found highly advantageous to corn- mence discharging the water as soon as the tub reaches a sufficient height above the pit, without bringing it to rest. An arrangemenit for this pur-,) pose is shown by the accompanying plate, reduced from ii a figure given by Burat in his atlas of Le Mat'riel des HouillBures. Instead' _. of bringing the tub i ii of water to a com- plete rest upon catches at the top of the shaft, it is kept slowly ascending, and strikes a * movable knocker or Apparatus for hoisting water. 132 MECHANICAL APPLIANCES OF MINING. frame-work, which throws open the discharge valve and lets the water escape. The motion may be stopped as soon as the valve is open, and as soon as the tub is emptied it may be lowered without any loss of time. The practical value of this improvement is shown by the results obtained with it at the Lucy pits, near Montceau-des-Mines. At these shafts, 200 metres in dlepth, 30 tubs of water, containing 25 hectolitres each, were raised per hour, being a total of 750 hectolitres of water; but this being insufficient, the automatic discharge apparatus was added, and the number of deliveries of tubs of water at the surface was easily increased to 50 or 60, discharging from 1,200 to 1,500 hectolitres per hour. The lift and plunger pumps used in California and Nevada are generally of small size, and have no special peculiarities. They are generally connected with either the engine used for hoisting or with that for running the mill. CHINESE UPIUMP In placer mining the " Chinese pump " is much used for draining the pits where the water does not require to be raised to a great distance. This is essentially a chain-pump. A continuous belt of canvas 5 or 6 inches wide has cleats of wood firmly secured to it at intervals, and is made to pass continuously through a rectangular box, the lower end of which is fitted with a roller over which the belt passes, and is inserted: in the water to be raised from the pit. The upper end delivers the waiter into a launder or trough, by which it is conducted away. The belt passes over a wheel at the top, and motion is given either by the hand or by a belt from- a water-wheel near by. DRAINAG]E BY SIPHONS. The siphon has often been brought into use for draining in mines, pits, and quarries,, where it was not necessary to raise the water to a great height, and where the necessary fall for the delivery end could be conveniently had. There has been a notable example of the successful use of a siphon on a large scale during the past year at a deep placer claim in Gravel Range, Tuolumne County, California, where Mr. George A. Treadwell employedi one a little over 1,000:feet long and 4 inches in diameter. This pipe was made of No. 24 galvanized iron, in joints 30 inches long, riveted and soldered together. The water was raised 18 feet, and the discharge end had a fall of 40 feet, so that thce delivery was 22 feet lower than the receiving end, or shorter leg of the siphon. The two ends of the pipe were furnished with large 4-inch brass, cocks, which were closed when the siphon was to be filled. The filling was easily accomplished in about two hours by means of a 3-inch Douglas force-pump, throwing water in at the highest point through a vent. cock, through which, also, smaller quantities of water could be supplied from time to time to displace air that gradually aceinulated through leaks. An air-chamber at the bend was projected, but was not made, inasmuch as it was found to be but little trouble by shutting' the 4-inch cocks at each end to fill up the siphon with the pump in a short time when the men were at their meals. The flow at both ends was easily controlled by the cocks, the lower or delivery cock being usually left fully open, while the receiving cock was partly closed. The velocity of the current was, sufficient to carry out tons of coarse sand and gravel, some df the latter as coarse as English walnuts; and sluice-boxes set at the usual slope were kept half ful RAISING WATER FROM MINES. 133 of water. There was no trouble in keeping the water within 2 inches of the receiving end, and this was plunged to within 5 inches of the bottom of the shaft. PUMPING ENGINES IN THE EUROPEAN MINES. There are.three principal types of pumping engines for mines: 1. The single-acting balance-beam engine, known as the Cornish engine. 2. The single-acting engine, working the pump-rods direct, without a balance beam. 3. The double-acting engines placed in the interior of mines. As explanatory of the construction and working of the first type, I insert a very clear and interesting description of a Cornish engine of the largest class: * CORNISH PUMPING ENGINE. The engine called Taylor's engine was erected in the year 1840, at the United Mines in Gwennap, now included in the Clifford Amalgamated AMines, and is worked with high-pressure steam, with expansion and condensation. It is single acting; that is, the steam is only employed for lifting the pump-rods and filling the pump-barrels in the shaft; the return stroke, which drives the water out of the pumpl-barrels into the rising pipes being effectecd by the fall of the shaft rod, as soon as an equilibrium is established in the cylinder, by opening a communication between the two faces of the piston. The steam piston moves vertically in a, cylinder formed of two concentric tubes, the inner one forming the cylinder, and the outer one a protecting case, or jacket; the small annular space between the two is constantly filled with steam at the maxizmum pressure produced in the boilers, in order to keep the walls of the inner cylinder at a uniform temperature. In practice, it is customary to surround the cylinder with other non-conducting envelopes; thus, a shell of brickwork inclosing an air space is first placed round the jacket, which is further inclosed with coatings of felt, lagged with awood. These outer envelopes are not shown in the model. The piston-rod is attached by Watt's parallel motion to the end of a beam oscillating about a horizontal axis, whose bearings are carried on the outer wall of the engine-house. The beam is formed of two parallel cast-iron plates bolted together, the two plates being kept a fixed distance apart by wrought-iron pins. The two arms of the beam are of unequal length; the steam piston and mechanism for working the valves are attached to the longer arm., which wor-ks within the engine-house; the main pumoprod and rods of the air and feed-pumps are attached to the shorter arm, which works in the open air; a gallery projecting from the wall of the engine-house gives access to the bearings on the out-door side of the beam. The engine has four valves for the distribution of the steam; three of these are placed near the top of the cylinder, and the other one is at the bottom. One of them is a plain disk valve, with a single conical beating face, and is independent of the engine; the other three are of the kind known as the double beat, or Hornblower's valve, a construction in which the bearing faces opposed to the pressure of the stealm are reduced to a pair of narrow conical rings, the valve and its seat being X This description is extracted from Bauerman's Descriptive Catalogue of the Mining Models, &c., in the Museum of Practical Geology,.attached to the London School of Mines. 134 MECHANICAL APPLIANCES OF MINING. so formed as to present a very large steam passage when open. Of the three upper valves, that on the right-hand side (as seen when facing the cylinder from the outside) is the governor, or regulator valve. It is a plain disk valve, which is maintained at a fixed opening by means of the setting screws on the rod attached to the right-hand pillar of the valve gear framing. By this valve the steam is adclmittedcfrom the main steamn-pipe through the large hollow column on the right into the top steam-chest. The central valve is the admission valve; it commands the passage whereby the steam at fnll pressure, enters and leaves the cylinder above the piston, and is governed by a system of levers attached to the uppermost of the three horizontal shafts, which are attached to the two vertical pillars or standards in front of the valve cases. The left-hand upper valve is the equilibriunm valve; it is placed at the top of a hollow column, through which the steam passes from the upper to the lower face of the piston, in order to establish an equality of pressure at the end of the steam-stroke; the movement of this valve is effected by the central arbor. The bottom, or exhaust, valve, which controls the passage of the exhaust steam from the cylinder to the condenser, is attached to the lower horizontal arbor. The valves are opened by falling weights, and closed by the action of tappets on the plug-rod, acting on curved handles projecting frojecting the front of the horizontal shafts. The sector-shaped calms and catch levers ontside the bearings of the horizontal arbors keep the valves locked in position during the repose of the engine. The engine is intermittent in its action, a pause being made after the descent of the main rod in the shaft, varying in duration according to the amount of water to be lifted; this is effected by a simple hydraulic regulator, known as the cataract. The cataract, which is placed in the well below the floor of the engine-house, is a square wooden plunger box, ol)en above and closed at the bottom, with the exception of a small conical hole, which can be stopped by a plug attached to a vertical rod; the plunger moves in a square cistern of water, a little larger than itself, and is attached to a vertical rod passing through a collar projecting from the right-hand frame pillar; it is further attached by a chain rolling on a sector-head to a double-armed lever, which oscillates about a horizontal axis; the shorter arm of this lever is pressed down by a roller at the lower end of the plug-rod, during the upstroke of the eingine, a balance weight being fixed to the end of the opposite arm, which raises the shorter arm when the pressure of the rod is taken off. The actionl of the cataract is as follows: When the in-door side of the beam makes its down stroke, during the lifting of the main rod in the shaft, the cataract plunger is driven down in its cistern, displacing the water in bottom of the latter, which consequently rises above the open top of the plunger box and fills it up; this water afterward flows out through tie small hole in the bottom of the box with more or less rapidity, according to the position of the conical plug; and deluring this time the valves are closed and locked by their catches, the steam piston is at the top of its stroke with a slightly compressed cushion of steam above it, and the expanded steam of the preceding stroke below it. As soon as sufficient water has flowed out of the cataract plunger to establish the preponderance of the balance weight on the longer horizontal arm of the lever, the box rises, and the rod attached to it opens the exhaust valve by striking against the catch lever and releasing the balance weight. The steam below the piston flows away to the condenser, and a vacuum is formed in the cylinder.. The catch on the steam valve is formed by the vertical arm of an angle lever, whose horizontal arm is parallel to RAISING WATER FROM MINES. 135 the exhaust-valve catch, and is connected to it by a parallel bar with a slotted link at the top, which works on a pin at the end of the horizontal armn of the upper catch. When the bottom of the link strikes the pin, the steam valve is opened in a similar mhanner to that already described for the exhaust valve. The piston descends under the full pressure of the steam in the cylinder until the link frame at the back of the plug-rod closes the valve, by pressing against the handle which projects from the top arbor, the sector on the arbor, in turning, gradually lifting the catch lever, which falls into its place as soon as the end of the cam has passed the notch. The steam is now cut off. and the remainder of the stroke is effected by the expansion of the steam already in the cylinder. The length of the full steam stroke is determined by the position of the link frame on the plugrod; the proportion of expansion is diminished or increased by raising or lowering the link by the setting screw on the front of the rod. The exhaust valve is closed by the plug on the right-lhanld side of the rod,,shortly after the closing of the steam valve. The equilibrium valve is opened at the end of the stroke by its balance weight; this establishes a communication between the upper and lower faces of the piston, equalizing the pressure on both sides, when the piston is drawn up in the cylinder by. the excess weight on the outer side of the beam. The equilibrium valve is closed by the left-hand plug during the rise of the rod. This confines a small quantity of steam above the piston, which forms a cushion by compression, and brings the moving mass to a state of rest. The condenser and air pump are connected with the out-door side of the beam. The latter is surmounted by an open hot well of large capacity. The feed pump draws its supply directly fromithe hot well, and forces the water through a double U tube, passing four times through the exhaust pipe, where it is heated by the waste steam on its passage from the cylinder to the condenser. The feed water is further heated by circulation through a system of horizontal pipes in a flue at the back of the boilers. The steam from the six boilers is collected in a cylindrical steam chest, with hemispherical ends, cast in two pieces, which are united by a wrought-iron expansion joint. The main steam-pipe passes from the chest under the floor of the engine-ho-use, and terminates in the right-hand vertical column, at the top of which the governor valve is placed. The main rod which works the pumps in the shaft is formed of two square balks of timber placed side by side, and united by wroughtiron fish plates and bolts. The excess weight of the rod above that necessary to drive the water out of the pump barrels is balanced off by five balance bobs, of which three are placed under ground and two are at the surface. The latter are cast iron beams, constructed in a similar manner to the beam of the engine, one end being connected by a wooden rod with the main rod on the shaft; the other carries a wooden box, which is loaded with masses of rock, acting as a counterbalance. Catch pieces, or stops, are fixed to either side of the beam to prevent it going beyond its proper distance in case of breakage on either side. The in-door catch is formed by an iron cross-piece fixed above the beam which is received on a pair of spring beams carried on horizontal balks crossing the upper part of the engine-house. The out-door catch is formed by two pieces of timber strapped on to the front of the main rod. The lower ends of these beams, which are of the same size as the main rod, are caught by a mass of timber formed of horizontal balks piled one above another in the shaft. This bed of timber is not shown in the model. 136 MECHANICAL APPLIANCES OF MINING. The large capstan and shear frame over the shaft lead the rope by which the pump barrels, &c.. are lowered in the shaft. It is worked by manual power. The following are the dimensions of the more important parts of the engine: Diameter of steam cylinder................ 85 inches. Length of stroke of piston....................... 132 inches. Diameter of regulator valve............. 10.8 inches. Diameter of admission valve-............-... 15.0 inches. Diameter of equilibrium valve................... 18.5 inches. Diamneter of exhaust valve....................... 25.0 inches. Diameter of main steam pipe.......... 18.0 inches. IDiameter of exhaust pipe........................ 24.0 inches. Diameter of condenser.............' 30.0 inches. Diameter of air-pump piston..................... 37.0 inches. Diameter of air-pump valve....................... 30.0 inches. Diameter of hot well........................ 55.5 inches. Diameter of feed pumlp..6................ 6.0 inches. Length of main beam............................ 34 feet 2-t inches. Height of main beam at centre.................... 7 feet ljj inches. Length of beam steam side...................... 17 feet 10 inches. Length of beamn out-door side.................... 16 feet 4 inches. Length from centre of beam to point of attachment of air-pump rod..-.....-....-. -......- 9 feet 7~ inches. Length of feed-pump rod.............- 6 feet 8 inches. Length of stroke of main rod. 1................ 10 feet. breadth.... 24 inches. Section stroke of main rod......... breadth... 24 inhes. depth...... 12 inches. Diameter of piston rod......... 7 inches. D)iameter air-pump rod.. -........................ 3 inches. Diameter of feed-pump rod..................... 21 inches.' Diameter of axis of main beam.................... 20 inches. Diameter of journals........................ 16 inches. Boilers: 4 of 30 feet length, 5 feet diameter of outer shell. 3 feet 4 inches diameter of inner tube. 2 of 34 feet length, 5 feet 10 inches external diameter. Steam chest, 30 inches diameter. Feed-pipe, 5- inches diameter. The engine was started in December, 1840; its performance was continuously reported in' Lean's Engine IReporter" up to the end of 1851. The most economical condition of working was reported in September, 1842. The mine was then 201.2 fathoms deep; the load on the piston amounted to 75,362 pounds, or 12.05 pounds per square inch of surface. The engine, making five strokes per minute, developed a quantity of work equal to 114.2 horse-power. The quantity of fuel consumed showed an effect of 107,494,580 foot pounds per bushel of coal of 94 pounds, equal to 1.74 pounds per horse-power per hour. The last return, in December, 1851, shows a duty of 62,000,000 of foot pounds per bushel, or 2.9 pounds per horse-power per hour. The depth had increased to 239 fathoms; the load per square inch tb 15.8 pounds, giving a duty of 165 horse-power, at a speed of 5.5 strokes per iminute. The greatest working speed attained appears to have been in December, 1849, when the engine made 7.5 strokes per minute, showing RAISING WATER FROM MINES. 137 221 horse-power, with a consumption of 2.4 pounds per horse-power per hour. The method by which the above duties s icomputed consists in comparing the amount of coal burned with the theoretical volume of water discharged by the pumps during the period of observation. The actual volume is, however, somewhat smaller, the dischalrge of the best mining pumps being from 24- to 2 per cent. less than the theoretical amount for each lift. DIRECT-ACTING PUMPING ENGINES. The models earliest imported from Englandl, or constructed in France or Belgiumn, were all of the first type; but they were gradually replaced by those of the second, or the direct-acting engines, so that the use of the beam engine became exceptional. The two types, though so different in form, do not differ much in the details of construction. They are both single-acting and are provided with the same kind of apparatus for the distribution of the steam; and the Hornblower valves, used in both, are controlled by one or two cataracts. In some cases, where there is very little space in which to place an engine, they are made without the condenser, and the cylinder is placed over the shaft, the piston-rod being connected directly with the pumprod. This is the simplest and least costly form of pumping engine to erect, but the expenses of working with it are of course much greater than with condensing engines. Instead of the consumption of one and a half kilogramme of coal per horse-power per hour, as in the Cornish engine, the high-pressure engines consume four to five kilogramnies. For this reason condensing engines of the Cornish type are generally used, and of these the direct acting form has been generally preferred, but with the addition of the beam, for the purpose of counterbalancing the rods and for working the condenser. Burat, in his Macteiriel des Houilleres, sums up the relative advantages of the two types of construction, the balance-beam engines and the direct-acting engines, substantially as follows: The balance-beam engines are especially adapted to pumping where great diameters of cylinder are required, because they do not obstruct the mouth of the shaft; because their foundations, being at some distance beyond the sides of the shaft, are much firmer and more secure; and because the different parts of the apparatus are more accessible for cleansing and repairing. The direct-acting machines are the best, when the cylinders do not exceed Im. 50 in diameter and the pumps? Om. 45. Their installation is more simple; they occupy less space, and can, in most cases, be placed over one compartment of a shaft used for hoisting, and without a special building; and the conditions throughout are much more simple than can be secured with the other type. A failure to obtain as great an economy of steam in many of the French and Belgian engines as is claimed for the Cornish engines has led their engineers to think that the statements of the performance of the latter are exaggerated. In reality the average consumption in Cornwall is lkil.50 of good coal per hour per horse-power. It is but rarely that the collsumption has been reduced to one kilogramme, when every part of the apparatus is in the most favorable conditon, depending upon the depth and diameter of the column, the size of the rods, and the proper relation of the force to the work to be done. 138 MECHANICAL APPLIANCES OF MINING. BLEIBEIlRG LIFTING PUMJP.' X -- ~The annexed figure reduced by U....... i7~ i~~ tle photo-relief process from Plate I'X 11 LXII of the Atlas of Burat's Materiel des Uouillbres, gives a seeIj l g /E:., I tional view of the pump barrel and t he two vales of a lifting pump at Bleiberg. It is one metre in dii I / -'~ ameter, and is made for a height of column of 22 metres. The pis-', a~1i, i"- I 11 Lrton can carry a charge of 17,000 E; B~~kilogrammes. The valve clham-'i'l'1 0ber B B is provided with a manhole E, securely closed by a cast l plate held in position by a bolt and nut ggy, passing through the cross-bar ff. The barrel of the ]'~~ ~lll:][[!pump is lined with bronze. It is 3m.45 high, and the piston has a stroke of 21118. The piston is pierced with eight triangular openings. The placking consists of a 4i circle leather firmly secured to the piston by a ring of iron j. The.lower valve is one of Hiornblower's 01iii'0 n j construction. EXPERUIMENTS AT BLEIBERG. In the year 1850 a commission was formed to investigate the 4a'1 1performance of the pumping ma1 chinery at the mines of lead and had exerted themselves to produce the most perfect specimens, ~~ zo. ^'l' with all the latest improvements /A of the best Cornish en oines. |%ttl0I8 i} J \ t of The steam-cylinder of the engine at Bleiberg was 2lm.67 in Yi diameter; (surface, 5n2.5990;) the olli jmean stroke rn3.65; the relation of -fI,1 ~ the tarns of the beam 6.4: 5; the'khA. stroke of the pumllp-rods 2111.85. / p s~The steam being at a pressure of 2.90 atmospheres in the boilers, the initial pressure in the cylinders was 2.42 atmospheres. The steam wvas cut oft at Om.70 of the stroke, and the resmainder of the movement was performed by the ic expansion and the condenser, so ~. ii w iIthat at the end of the stroke the steam occupied a space equal to Bleiberg Liftfno PuRump five times its primitive volume. RAISING WATER FROM MINES. 139 The commission continued the observations from the 9th to the 15th of January, and reported them in detail.* The engine having worked during 127 hours 15 minutes, gave 50,043 pulsations, and 43,118 kilogrammes of coal were consumed. This coal was the stone-coal of Seriang, broken to the size used in Cornwall. The stroke of the pumlps was maintained uniformly at 2n1.85, and the effective height of the column of water at 71m.50. The result of these figures was that the machine gave a mean useful effect of 234 horse-power, and the consumption of coal per horse-power per hour was an average of lkil.448. Burat finds the relation of the force exerted to the effect produced to be as 377:234-1: 0.621; and observes that this remarkable economy of fuel in a work which is far from being advantageous to tthe motor since at each stroke it must overcome the inertia of an enormous mass, results from a series of favorable conditions in which the zmachines are established and work. These favorable conditions may be stummed lup as follows: 1. Generation of steam in boilers with large heating sur. faces; good coal and good raking. 2. A steam chest of great capacity, and pipes and openings of large diameter for the admission and emission of steam. 3. Condensation as perfect as possible. 4. Expansion developed as much as possible, favored by the conditions of single action and the inequality of speed of the piston, which are coincident with the best conditions of movement for a column of water. PUMPING ENGINE AT GRAND HIORNU. The great pumping engine of Grand Hornu was constructed at the works of Seriang, for a shaft 460 metres deep. It works a series of eight plunger-pumps and two lifting-pumps of Om.50 in diameter, and four metres stroke. These pumps are placed one above the other, at distances varying fromn 30 to 60 metres. The upper plunger-pump, 60 metres from the surface, is worked by a double rod, each arm having a square section of 0mn.484 x 0m.242, and being formed by the juxtaposition of two pieces of 0 2.242. These rods are completely enveloped in iron 0m'.024 thick. The double rods gradually diminish in size toward the bottom of the shaft, but in each section the weight exceeds that of the column of water to be thrown out. The total weight to be counterpoised is 200,000 kilogrammes; and this is effected by two balance beams mounted upon opposite sides of the master-rod, directly below the engine. The engine is direct-.acting, the cylinder being mounted directly over the shaft. It has three floors or stages: 1. The cylinder; 2. The condensers, with their air-pumps; 3. The balance beams. The cylinder is jacketed to prevent condensation. It is 0m.05 thick and is made in two pieces, each 111.60 high. There are three valves: the admission valve, 0m.42 in diameter and rising 0m.06; the equilibrium valve, 0m.51 in diameter and rising 0nl.08; the exhaustion valve, Om.60 in diameter and rising Om.85. The condensers have a diameter of Im.20, and are 2n1.50 high. The air-pulmps are 0Q.95 in diameter, and have a, stroke of 2m.10. The balance beams are 1111.40 long, and each carries 90,000 kilograimmes of counter-weights, formed of plates of cast iron. QUILLACQ'S PUMPING ENGINE. At the Paris Exposition of 1867, M. Quillacq, who has already been mentioned as the constructing engineer of hoisting machines, exhibited the drawings of a very perfect specimen of pumping engine recently Proces-Verbaux de la Commission contradictoire. 140 MECHANICAL APPLIANCES OF MINING. erected by him at the mines of Fiennes, in theBotnlonnais, France. This was a single, direct-action engine, without the beam, as in the Cornish type. The cylinder is provided with ajacket of cast iron, inclosing a space in which steam circulates. The distribution is made by three valves of admission, equilibrium, and exhaustion, controlled by a double-acting cataract, which determines the time of rest at each extremity of the stroke. The cylinder, 2mn.65 in diameter, is 4m long, and supported by two wrought-iron girders lm.35 high, placed in the walls of the building. The steam is admitted in the cylinder under a pressure of 3.75 atmospheres, and is cut off at half-stroke. The condenser has two air-punps of 0".90 diameter, and 2m stroke. The water is injected through two valves, one of which opens at the same time with the introduction of the steam, and the other at the same time with the iscape-valve, so that at the beginning of the stroke the two valves are open, while at the end one of them is closed. This machine is designed to raise water from a depth of 400 metres, by means of six plunger-plLumps, and a lift-punp at the bottom. The (diameter of the pumps is 0m.60 and the stroke 4m.00. The principal rod which transmits the movement to the pumps is of iron and weighs 200,000 kilogramnmes. The following are the weights of some of the principal parts of the engine in kilogrammes: Steam-cylinder....................... 40000 Iron girders....................................... 12,000 Piston -rod............... I............. 4,000 Cross-head....................0..................... 1600 Two equilibrium balances.....-............................ 40,000 The total weight of the engine and fixtures, without the counterpoise, is 175,000 kilogrammes. The other elements areSix plunger-pumps........-........................ 70,000 O1ne lift-pump....7... -7................................ 7,500 Main rod.-......................................... 200,000 Counterpoise attached to the rod....................... 75,000 Counterpoise attached to counterbalances.............. 140,000 The total weight of the masses put in motion, including the piston and the beams, is 465,000 kilogrammes. DOUBLE-ACTING PUMPING ENGINES-STEAM PUMPS. The double-acting pumping engines placed in the interior of mines have been applied at depths of 100 to 150 metres, and for quantities of water reaching 10,000 hectolitres a day. The Blanzy coal companies have applied this system in their mines. They have erected a 300 horsepower engine at a depth of 340 metres, to throw 25,000 hectolitres of water to the surface daily. The drawings of this engine were exhibited at Paris, in 1867. The apparatus consists of two horizontal steam.-cylind(ers. working four horizontal plunger-pulmps, which force the water into an air-chamnber with which) the delivery column, 300 metres high, is connected. The apparatus is placed 40 metres above the bottom of the mine, and the water is lifted to that point by four lift-pumps, so that in case of accident or stoppage the pumnps will not be covered with water. There are many different forms of the double-acting steam pumps in the United States, and some of them have been successfully used in mines upon the Pacific slope. It is not possible here to describe all of RAISING WATER FROM MINES. 141 the varieties offered to the public, and to discuss their relative mnerits. To single out one or two for description would not be just to the many inventors who have carried these pumps to great perfection. PUMIPING AT THE SAXON COLLIERIES. The following is cited from the notes of Mr. ~W. Fairley, as an example of pumping at the Saxon collieries: The Pumping Engine Company at Zwickau, which drains the water from the Bockwa. Manor, is worthy of notice. This mlanor is about 180 acker, or about 190 Englislh acres area, and the company pumps the water for the different coal companies for the payment of a tax of 21 groschen per 10 centner, or 6d. per toll English, of coal worked. The water does not exceed altogether more than 200 cubic feet per nminute, and for lifting this they have two engines, one 84 inches (Saxon) diameter, 11 feet in the cylinder, andlc 9 feet stroke in the pump, working seven strokes per minute as the maxilurnm. The pumps are two 23 inches diameter, forcing 250 feet long each, and one 23 inches diameter, lifting 100 feet long; the other engine is direct-acting, 68 inches (Saxon) diameter, with 10-feet stroke, working a 174-inch set. For supplying these engines with steanm, there are seven egg-ended boilers, each 7 feet diameter and 40 feet long. WATER-PRESSURE ENGINES FOR MINES. In mountainous regions, where water under a considerable head or pressure can be hadl, it may be advantageously utilized for pumIping, hoisting, or other mining operations requiring power, by means of hydraulic engines and surface or underground wheels. There are many places on the Pacific coast where such engines can be introduced with advantage. They are usually constructed for pumping only, and are singleacting, with long cylinders placed vertically over the pumll) shaft, the pumnp-rod being simply a prolongation of the piston-rod. The water is adnlitted to the under side of the piston, and when it has run its upward stroke the water is allowed to flow out and the piston descends. The absence of any sensible elasticity in water renders the lmotions resulting froml its use under pressure in engines susceptible of perfect control: but the same inelasticity causes sudden shocks and blows to the moving parts if the inlets and outlets are made as in engines operated by the elastic fluids, steam or air. It is therefore necessary to use valves of peculiar construction, by which the flow of the water mlay be gradually increased or slackened, and to provide other means for preventing impact and securing smoothness of action. Many such engines have been constructed for pumping mines abroad, and have operated successfully for long periods with very little expense or attention. One was erected by the engineer Trevithick at the Alport mines, in the year 1803, anud worked continuously for forty-seven years, until 1850, when work upon the mines ceased. In this engine the water was admitted first upon one face of the piston and then upon the other, alternately, and the inlets and outlets were opened and closed by two pistons at the side. An engine erected by Mr. Darlington at these mlines had a, cylinder 50 inches:in diameter and a stroke of 10 feet. The cylinder was placed directly over the shaft and the piston and pumnp-rod were continuous. The column of water was 132 feet high and gave a pressure upon the piston of about 58 pounds to the square inch, or more than fifty tons upon its area. Waiter was raised fiom a depth of 22 fathoms by means of a plunger 42 inches in diameter, and when the mine was very wet, nearly 5,000 gallons of water per minute were discharged into the adit. The water under pressure was admitted under the piston only; cylindrical valves admitted a ftll flow for seven-eighths of the stroke only, and then 142 MECHANICAL APPLIANCES OF MINING. commenced closing, while a small valve opened and allowed enough water to pass in to complete the stroke. The largest engine erected by Mr. Darlington was similar in its general construction to that just described. It had a cylinder 35 inches in diameter; stroke 10 feet; pressure column 227 feet high. Its average speed was 80 feet per minute, and its greatest speed 140 feet per minute. The pressure of the water was 98 pounds per square inch, giving a total weight of 40 tons upon the piston. This engine was automatic, the motion was certain and regular, and the cost of maintenance was trifling. Sir William Armstrong has made use of water pressure obtainedi from natural falls to produce rotary motion by means of a, pair of cylinders and pistons, with slide valves, in some degree resembling those of high-pressure steam-engines, but provided also with relief valves. TWater-pressure engines of this description were erected at the lead mines at Allenheads, in Northumberland, and are used for the various operations of crushing the ores, hoisting, pumping, and driving the machinery of the concentrating works. Small streams of water which flowed down the slopes of adjoining hills were conducted into reservoirs at elevations of a-bout 200 feet, and from thence by pipes to the engines. In a mining district upon the river Allen, in Englandcl, where the fall of the water is not sufficient to work water-pressure engines, overshot wheels have been used to force water into accumulators, from which it could be conveyed in pipes to the required points. Table showing the locality, engineers, and dimensions of some of the principal water-press,,re engines. [Fronm Ure's Dictionary, edited by Robert lunt.] Locality. Engineer. In's. Feet. Rev's. Northunmberland.................w........ Westgarth-.-..............-.,,, 1. 10..... Ems U..-..-.......................... Tnknown............................. 13 4 8 Bleiberg.-...Unk........ Unknownm.-..-.....-........ 7 6. 100 clhemlitzU. -...................... Unknown —i.i................. 17 84 48 Ebensee, Salzsburg... Unknown..-.... ---.. —......... 91 1 5-12 17 Clausthlal..-.-................ Unknown..-.............. 164 6 48 Alte Mordgrube, Saxony................. Unknown.................18 8 64 Alport mines, Derbyshire -................ Trevithick2........................... 25* 10 120 Do.-..-.................... Fairbairn.-. —---........... 36 5 70 Do..-. —...- -..I —..... ]Darlin gton........................... 50 10 140 Do..............................d.. o............................... 18 7 154 Do.-........-............ do. —..-. —-----------—. —----- 24 f 10 120 Do..-d.......................-...... - o.. —.-.-.-.-.-.-.-..- 24t 10 120 Lisbn1rn —------------- d —-- (o --------------------------- 20 t 6 96 Cwmystwyth.-..... —.... do.. -—..... ----- 241 10 140 Talargoch-.-..*............- do - 50 10 140 Minera.-................ —. do. —------------—. 35 10 140 Wildberg...............-..... do. ---------------------- 3 5 80 South Helton colliery. -..A.......-..... A rmstrong................... 3 + 12 200 Allenheads do-6 18 180 " Double. 1 Two cylinders. + Four cylinders. Underground water-wheels are used in various parts of Germany, when the circumstances permit. Where a system of mines is drained through a deep adit, the water caln be transferred from one mine to another, and its fall utilized by such wheels, until it finally reaches the level of the adit by which it escapes. Instances of this may be observed in the district of Freiberg, Saxony. RAISING AND LOWERING MINERS. 143 WVATER-W ORKS AT WVHITE PINE. There is a very interesting exhibition of hydraulic engineering at the White Pine mines, due to the skill and enterprise of the distinguished engineer A. Von Schmidt. Water is there pumped a height of 900 feet in round numbers, in two lifts of 450 feet each. There are four large steam engines, two at each station, and each engine of 177 horse-power. The cylinders are 22 inches in diameter and they have a stroke of five feet. They can be worked together or independently. The water is forced through 12-inch pipes of boiler iron, and the capacity of the works is reported as 2,500,000 gallons daily. CHAPTER XII. RAISING AND LOWERING MINERS. The ascent and descent of miners in the mines of the West, when of depths not exceeding 200 feet, is' usually by ladders in one compartment of the hoisting shaft; but in all guided shafts where cages are used it is customary to descend and ascend in these cages. This is not only dangerous, but it interferes with the work of hoisting ore; and in all deep mines, especially in vertical shafts, it becomes ilmportant to provide some other safe and rapid means of hoisting and lowering the men. This necessity has been met abroad, and in some of our mines upon Lake Superior, by the introduction of the man-engine, known in Germany as the Fahrkunst and in France as echelles imobiles. They are all alike in principle, and consist essentially of two strong beanms or rods hung side by side in the shaft of a mine. Each beam has platforms or landings large enough for a man to stand upon placed at equal distances from the top to the bottom. Handles to be grasped by the hands of the men are attaiched at a convenient height above each platform. They are not a modern invention, having been known in Germany during the last century; but they did not become generally used, and were almost forgotten, until about forty years ago. Since then they have been used extensively in Germany, Belgium, and Cornwall. In the year 1833, when the deep George adit was opened in the mines of the Harz, two water-wheels were thrown out of work, and the idea was suggested of using the pump-rods attached to them for the ascent and descent of the miners. The experiment was tried. The rods were strengthened, stages or platforms were attached at suitable distances, and a regular alternate up-and-cldown motion was given to them by means of the wheels. It was a great success; the miners were relieved from most of the arduous labor of climbing, and even invalids, who before could not reach the lower parts of the mine, were enabled to resume their work. The principle of the man-engine will be made more clear by reference to the: annexed diagram. RI R and iR' R' represent portions of two heavy rods or beams, extending from the top to the bottom of a shaft, and suitably guided and supported throughout their length. To these rods, and at equal distances, small stages or platformls, A B C, and A' B' C', are securely fixed. An alternate upward and downward. movement is given to each of these rods; while the rod IR. with its stages is ascending, the opposite rod R! is descending. This movement brings the platform A on the rod 144 MECHANICAL APPLIANCES OF MINING. R opposite to the platform B' on rod R', and the platform B opposite the platform C'. The motion is then arrested for a moment, and is immediately afterward reversed, and the platforms return to r D their original position. If miners are standing upon the R platforms of R, they will all be raised by the upward movemelit a distance equal to half the distance between the platforlns. At this point, the motion ceasing, the miners step from the platforms of the rod Rt to those upon the rod RI, and by the next movement are again lifted, when they step across as before, and so on until the top of the shaft is reached. The descent is similarly accomplished. -. In some mines only one of the rods moves, and the other / remains stationary, or rather the second rod is omitted, and stages are fixed to the side of the shaft in the rock itself; in such cases the single rod has to move the whole distance between two stages instead of half that distance, as when two rods are used........ When a single rod is used in connection with fixed stages, the miners pass alternately from the stage on the rod to the'stage fixed in the rock. They then wait until the half-stroke brings a freshi stage opposite to them, on which they place themselves, and so on. The distance between two stages on the same rod generally varies from 4m.50 to 8m.00. The stroke of the apparatus with two movable rods is always half the distance between the stages, consequently it varies fiom 2m.25 to 41n.00. There are from folur to eight double strokes per minute. The single-rod man-engine is the one most used in Cornwall. It makes three strokes of 12 feet each per minute..... - The rods are generally about seven or eight inches square, decreasing in size toward the bottoml. The weight is counterbalanced by levers or by balance-bobs, attached at different levels. Motion is imparted to the rods of the mlan-engine by AA. means of water-wheels with cranks, steam-engines with cranik-imotion, or direct-acting steaml-engines, the two rods being connected by balance-beams in such a way that their R t'fi motion, though inverse, is equal and simultaneous. M. Warocqu-t substituted for the cumbrous balance-beams a column of water, contained between the pistons of two cylinders side by side, and connecting freely below the pistons, and made other improvements so important that the echelles imobiles are described in some publications as TIVrocqueres. The crank motion is particularly well suited to the movenment of the man-engine, inasmluch as the velocity of the movement decreases gradually at the beginning and end, and becomes almost nothing as thecrank passes the centre, thus giving time for the miner to step from one beam to the other, or from the beam to the stage fixed to the side of the shaft. When direct-acting engines are used, there is a stoppage after each stroke to give the mIiners time to pass from one stand to the other. This stop varies from two to eight seconds, which is ample, as the passage from one stand to the other does not talke more thatn one second. This would be a very good system if the stop were always rigorouslythe same. But all who have worked the mnachitne with direct single action and cataract know that it is impossible to obtain this regularity. The RAISING AND LOWERING MINERS. 145 irregularity luay indeed cause accidents. The miner, relying on the nor mal time of the stoppage, may be surprised in the midst of the nmovement he is making, and as the single-action engine starts suddenly, and very quickly acquires a great velocity, he may have one leg roughly taken up while the other remains on the stage which rapidly goes down. When the man-engines receive their reciprocal motion firom a crank: on a revolving shaft, there is, so to speak, no stoppage. The stages which approach each other are hardly on the same level when they separate again; but by taling care to have the machines provided with regulators and heavy fly-wheels, the movement is regular, and there is no change to surprise the miner at the moment of his passage fronm one stage to the other. It must not be forgotten that the mlovemnelt of the mnachine being uniform, that of the connecting-rod which colmmands the man-engine is variable. It is very slow at the commencement of its stroke, is accelerated at the middle of the stroke, and becomes slow at the end. The ~miner, thanks to the regularity of the movement and the slowness of speed, when the stages approach the same level and separate from each other, can begin his passage from one rod to the other a little before the stroke, and continue it a little after. Experience proves that this second method is the safest. The persons who go down for the first time on these machines do not experience any disagreeable sensation. It is not so with the single-actinlg mlachines; when, after the stoppage, the stagfe lifts or lowers a person suddenly whlo is not accustomed to theme, he experiences a disagreeable sensation, (a sinling at the stomach,) which is increased by the sudden stop at the end of the stroke. This feeling is similar to that experienced when one is lowered or " dropped" suddenly in a cage; and, with some persons, produces sickness and fainting. In the Saxon mines, at Freiberg, the movement is given by water-wheels and cranks; and there is nothing about it unpleasant or awkward to any one accustomed to life underground. The writer, after watching the movement of the rods for a few moments in one of the shafts, stepped upon and used themn without difficulty. There is altways tlhis advantage to one unlacctustomed to them, that if, froml any cause, tile step from one stage to the other is not taken in tilme, it is perfectly safe to remain upon the rod and be lowered and hoisted again. Man-engines worked by direct-acting engines, in order to raise the salne number of men in a given time, must move more rapidly than when the motion is communicated by a crank. Let us suppose two man-enugines, worked by these different engines, having a stroke of 3111.00 and making 6 double strokes per minute. The speed per minute is equal to 311 x 12 strokes single: 36m1. Therefore, while the crank machine will take 60 seconds to go over these 361n.00, or a mean velocity of' 0ll.60, the single-acting engine will take 60 seconds diminished by 12 stoppages, which are generally of 2~ seconds =30 seconds; its speedl must then be double —llr.20. The diagramns annexed clearly indicate the difference that exists between the working of these two methods. In these curvees the abscisses represent the nlumber of seconds fro-m the beginnipng of an oscillation, and the ordinates the corresponding spa!ces passed over by a stage. The machine with single action predominates in Belgiumn, while the crank machine is more used in Germany and England. The single-acting machines are generally placed directly over the shaft. These engines are composed of two steam cylinders joined together; 1) M IN 146 MECHANICAL APPLIANCES OF MINING. the piston-rods are attached directly to the man-engine. The steam acts directly and alternately underneath or above one or the other of the pistons. < Ascending. > < Descending. >;Vorking curve of the stage of a Man-engine when actuaited by a double-acting engine. Ei Bit i. I; \ 91, < Ascending. > < Stoppage.> < Descending. > < Stoplpage. > WA*orking curve of the stage of a Single-acting engine. IBut there is an important condition to be observed, which coniplicates this arrangement a little. The platforms of the man-engines mnst have exactly the same v-elocity, and the strokes must terminate at exactly the same moment, so that both sets of platforms will be connected. This problem has been solved in two principal ways. One method, designed by AM. Hanrez, is to connect the rods by a piniolln, as shown in the annexed fignre.A strong rack is placed on each ro(l, and these work into opposite sides of the same pinion, steadied by an intermediate guide-rod. Unifortnity of motion has thlus been secured, for it is evident that when one rod descends the other must move simultaneously and equally. Every precaution has.been taken bythe constructor to prevent breakage. The teeth of the pinion and the racks are strong and carefully cut; and very few accidents have occurred. The other method consists in extending the piston-rods through the upper cover of the cylinders, so that these two rods may be connected by a chain working over a pulley. They then necessarily move silmulltaneously. As a pulley working between the cylinders would have too From Plate L, l Mate'riel des Houilleres, Burat. RAISING AND LO'WERING MINERS. 147 smlall a cdiameter, two leading pulleys are p)laced over the cylinders surmiountedl by a larger one. MI. Hanrez hnas also proposed to do away with the racks and pinion by the substitution of two balance-beamis connected with a; third and central balance. The plani of rolling up and unrolling chains over pulleys is credited to M:. Colson. W\Then the motion is impart-' e(dl not by a direct-acting engine, as we have just been considering, but from the rotation of a crank, it is also U necessary that the two rods should bl e connected together ill or(ler to secure a. eqlal ]. amplitude and speed of move-, 1 rnent. Some of the principal - methods will be briefly noticed. -.':, In gener al, balance-beams and: -. varlets are worked together by a connecting rod, moved by _' _ _ another connectiing rod, taking its motion fri'om a gearing, the pinion of which is placed on the main shaft of tile steamengine.' = The annexed figure, will give an idlea of this arrangement. To avoid- the great expense in- r curred by these balances, -Mr. asrfdl). sulspeynds thle rolds to;Gelaring of Man-en-iune Rods. flat cables, which pass over leading pulleys, and are attached to the two extremities of a wagon rolling on rails and worked by a connecting rod mloved by the engine. An ingenious arrangement by Messrs. Vaux and Guibal has been tried, but its utility has not yet been established by practice; but it is, nevertheless, worthy of being noticed. Two cylinders are placed above the rods, as in the direct-acting engines. The engine gives motion to a strong pump witho:t valves, which alternately forces and draws water from the cylinders over the shaft of the mine, thus alternately raising and lowering the pistons attached to the rods of the man-engine. The result is an alternate and opposed action of the rods. This plan would be excellent if the loss of water could be prevented. MI. Colson, at one of the reunions of engineers at Hainault, AIons, described some improvements which lie had made inl the form and construction of the rods.? Instead of making the rods of a continuous piece for the whole depth of the mine shlaft, ~which requires them to be strong enough at the top to carry the whole wvte:t of the apparatus, MI. Colson divides them into a certain number of small shafts, suspended by chains to pulleys, balancing themselves two and two. These isolated rods are much lighter than in the other construction. The principal rod, extending clown the - Burat: Matiriel des Houirii&es. 148 MECHANICAL APPLIANCES OF MINING. /~~~~~~~~~~ ODLL,4~~~~~~~~~~L Aagn f ) Ca Co CtoCD Ct Co o a Arrangement for com-municatting motion to the rods of a Man-engine. RAISING AND LOWERING MINERS. 149 whole depth of the mine, binds the small shafts together without supporting them; therefore its strength must be proportioned only to the strain it has to overcome, which is very little compared with the strain in the man-engines with continuous rods. M. Colson gives a stroke of 10 metres, -which he obtains by the alternate winding and unwinding of two cables. The velocity of movement until now, except in the Colson machine, has never exceeded 50 metres per minute. The cost of construction varies considerably according to the construction, and, above all, according to the price of materials and labor in different countries. It varies between'75 to 200 francs a metre. for a depth of 200 to 500 inetres. The engines made recently are nearer the lesser price, and hardly exceed the sunm of 100 francs per mnetre. The power required for the movement of the man-engine varies from ten to fourteen horse-power for 100 metres of height. The amplitude of motion, as already stated, varies from 2m.25 to 4m.00, but in Colson's form it is from 10m.00 to 15mn.00. In Cornwall, it is about twelve feet. The rods.-The rods are either made of wood or of iron. Iron is liglter, with the same power of resistance, and requires less room. Whether the rods are made of wood or of iron, they are all made with a decreasing section from the top to the bottomI of the apparatus. The wooden rods are made in two ways-either of beams adjusted end to end, like the rods of liftin g pumps, or they are made with planks, the ends of which are stepped together, as indicated in the annexed figure. Gradually, as the load to be carried allows of it, a plank is left out, so as to reduce the weight as much as possible, and yet retain all the necessary solidity. Iron rods have been im-ade in various forms, but generally in the shape of angle iron. The round or flat iron has the inconvenience of allowing too much vibration, especially at the bottom. The number of rods for each side of the man-engine may be one, two, three, or four. The single rod is generally used in the inclined shafts. It is composed of a piece of wood running on rollers at about six or eight lmetres apart. These rollers of wood or castiron are laid on sills of wood fixed in the rock. The staPges or l)latforms are made of planks large enough to receive both feet, and are firmly supported by iron brackets below; iron handles are securely fixed by bolts to the rods, at a height of about 11.00 to 1m.30 above each stage, to enable the miner to keep his balance. WNhere the rods are separated by fixed ladders, as in some instances, the distance required to pass over from one stage to the other varies from 0m.65 to 0llm.75, which renders the apparatus in commodious and even dangerous. The stages are sometimes made large enough to carry two men at once, which permits the miners to pass each other with ease in going up and down, some ascending while others are descendcling; but in Freiberg the ininers pass each other without much difficulty on the small and single stages. The laending places or stages.-The stages are made of the lightest wood possible, and their dimensions vary according to the space at command; they should not be less than 01n.50 to Om.60 square; but some are made which are only nm.40. But with these small dimensions they are dangerous. These stages are generally put in iron frames, which serve at the same time to bind the rods. When two stages, one on the ascending, the other on the 150 MECHANICAL APPLIANCES OF MINING. descending rod, are level with each other, the distance which separates them varies from 0'1m.03 to 011.25, and'even to 01nm.30. When the space is wide, there is danger in crossing froml one stage to the other, for the miner may step into the empty space and. be precipitated to the bottom. But if, on the contrary, the space is very narroTw, the passage is very easy, but there i:; danger that the miner imay imprudently let his head or his shoulder lproject beyond the stage ol which he is, so as to be struck or caughtlby the stage of the opposite rod during the movement. This difficulty is avoided in two ways-either by imaking the stage in two pieces, one fixed and the other hingedl, so that it rises when it meets withll an obstacle, or in fixingl under each stage inclined planks, well dressed and smoothed, wThich push against an obstacle and f'oree it back within the limits of the opposite stage. This last plahn can only be used where the movement of the man-engille is not too rapid; if the motion is rapid, the first is preferable. The hinges of the stages are made either of copper or of very strong leather to avoid oxidation. In the mines of Freiberg, Saxony, the stages are not placed opposite each other, but side by side. Balacnce weights and pulleys. —The rods and stages work itn guides at distances which vary froml twenty to fifty lnetres from-l each others. But this is not sufficient. It would not be pruldelnt to leave such a mass, 200 to 500 metres long, suspended without any other support. The whole weight is therefore balanced by what are called balance pulleys. They are placed two and two alongside the rods. The opposite rods are then connected by chains, w-hich pass over these pulleys and thus sustain aI part of the weight of the rods. The weiglht of one rod al so counterbalances the weight of the other. Adjust__ | | ing screw rods at the ends of the -i-t1 jchal n-s g ive the ___ i- I -1 1 —-i + tlhe lengt.h of the "_ -"~ [ I' i!, lchail so ils to secure the proper strain on each suptohr i e central ladder-way, aiidt portorl-mlley. Tell, arra n t ge Ill tpO f tle leys ad chains,.~ < 1511'-W Iare shown in the ""' i ill. II __]_'P7'The hydraulic'' ~tbalance has been 2i ttried for the samne ~__ J)urpose. Itis corn-,~~iii~ll- \- F Posed of two pistons: oel is l)laeed -____I1 onl the first set of I rods, the otlier on tile second. To Support of the rodis of the,Maii-engile ill anl ilcliled stlaft. these l)istu1ls two RAISING AND JOWERING MINERS. 151 pump-barrels correspond, connected with each other by a pipe giving free communication. The deseending set of rods, taking the piston with it, forces the water into the other pum-p-barrel, and as the water has no outlet, it forces up the other piston, lifting the other set of rods with it. The hydraulic balance would be very good if the packing of the piston could be kept tight. Unfortunately it cannot; water is lost, and then the descending piston does not transmit its pressure to to the rising piston before some part of the stroke is lost, so that the balance is disturbed. It has been abandoned for this reason. When the luma-engine is single-acting-that is to say, where there is not mnore than one rod and the other rod is replaced by a line of fixed stages —the rod must be balanced to p)revent the shock it would receive at the bottom by the impetus gained during its descent. This balance call be obtained by chains attached at different heights of the lift, passing them over pulleys attached to the rock and attaching to their ends counterpoises of sufficient weight. Such an arrangement is very dangerous fromn the liability of the chains to breakage. In England such pulleys are replaced by beams carrying balance weights; but although this arrangement is safer, it is much more expensive. The stroke, always a long one with a man-engine, requires beams of large dimensions, and they cannot be lodged in the shaft without making very large excavations in the rock, which are very expensive. Hydraulic regulators.-To regulate the descent, a hydraulic regulator or brake is also used. It is a pump furnished with a suction-valve, and the outlet of the pump is furnished with a tap. The piston of this pump is fixed to the. shaft of the lift; when this latter rises the pump fills with water; when the piston falls the water can only escape by the small opening, and the issue can be regulated by the tap. The rapidity of descent may thus be varied at will. Operation of the tman-engine.-We may now compare the different methods for the ascent and descent of miners, and note the great saving of time and strength resulting from the use of the man-engine.* To go down 100 metres of ladder requires about 15 minutes, (900 seconds,) equal to 9 seconds per metre. If we suppose that the men follow each other at 2 metres distance, after the first man has arrived at the bottom of the shaft it will be 18 seconds before the second man gets to the bottom, and so on; so that, if the shift is composed of 200 men, it will require 900 seconds + (200 x 18 seconds) = 900 + 3,600 seconds - 4,500 secondsj or I hour 15 minutes, for them all to descend to the bottom. If the shaft is 400 metres deep, 15 minutes per 100 metres must be added for the descent of the first man, which makes altogether 2 hours for 200 men. With this basis for calculation it is easy to find the time required for the descent of any number of men to any given depth. The ascent of 100 metres of ladder requires about twice as much time as the descent; then, if we take the depth of 400 mletres, and the number of men 200, we have for the descent by ladders 2 hours, and for the ascent 4 hours-in all 6 hours, which, added to 8 hours' work per shift, makes 14 hours, during 6 hours of which the work in ascending and descending is much harder than the actual mining. It is implossible for men to continue to perform such labor, so that in most mines over 250 metres dceep the hours of real work are shortened and the balance of the time is set apart for the work of ascending and descending. This comparison as well as other details respecting the man-engine are taken from the Exposition reports. 152 MECHANICAL APPLIANCES OF MINING. The Polytechnic Society of Cornwall, in comparing the rate of mortality among men working at different depths, (accidents deducted,) estimates that in works of 400 to 500) metres in depth, where ladders are used, the lives of the men are shortened by twenty years. However this may be, it is certain that the prolongedl use of ladders gives rise to serious derangements of the orgains of respiration, and renders a certain nuniber of men unfit for work before they are thirty years old. The time required for lowering and raisingl a shift of men by cables is not as easy to estimate as that required where ladders alone are used. It depends, in fact, on two variable elements-the rate of speed, and the number of mean that can be lifted at each time. The rate of speed varies according to the importance of the workings; in shafts without guides it is often froml one to two metres per second; in shafts provided with guides and cages, it is from three to twelve metres per secondl; but when the men are taken up and dowin in the cages, the speed is often slackeneed, keeping it about three to six metres per second. The, nutmber of men carried at once is from two to three in the small workings, and sixteenl to twenty, or more, in mines of greater extent. A comparison of the time required for the descent by ladders and by lowering iil cages may be made as follows: Assuming' that there are 200 men in a shift and that the depth is 400 metres, the rate of speed, averaging, say five metres, and that eight men are carried at once-at five metres per second, to ascend or descend 400 metres requires 4~ ~-80 seconds. To this must be added about two mlinutes (120 seconds) for the stepping in and out of the men, and the starting adcl stopping of the engine, wnhich nakes altogether 120 + 80=200 seconds. Lowering 8 men at once, we have 2. -0-25 journeys in all for the shift the time will therefore be 25 x 200 secondls —5,000 seconds-1 hour 24 minutes. Doubling this for the entire time in going into and out of the mine, will be 2 hours 458 minutes, which is hIalf the time taken for the ascent and descent of the sanme number of men by ladders. But these figures are not absolute; they may vary widely, either more or less, according to the extenit of the workinigs. The advantages and disadvantages of the rope are inversely to those of the ladders; the health of the men does not suffer, but there is less security, and accidenlts are much mIlore serious. Accidents by ropes and by ladders are as 3 to 2; but this ratio is still increased by the fact that of 100 accidents to men, 94 are killed and 6 injured. These deplorable consequences fromn this method of transportation of miners caused the Prussian government to prohibit the lowering or raising of mnen by tIle cages in. the mines of Prussia. In order to estimate the time required for the ascent and descent of miners.by the uman-engine, let us take our standard examiple, 400 metres of depth, and 200 men to send down or lift up for each shift. Allowing the stages to be 6 metres distant firom each other, and the man-engine to make 6 double strokes per minute, in one minute a man will then have passed upon and from 6 stages; he will then have been lifted 6m.00 x 6 —36m.00, and consequently will rise the 400 imetres; in 4 -- 0-12 ilinutes, in round numbers. Each double stroke thereafter will (leliver another man at the surface, or, which is. the same thing, the machine will lift 6 men per' minute; the 200 men will therefore arrive at the surface in 2 O__ 34 minutes in round numbers, which, added to the 12 minutes required for the whole ascent of the first man on the stages, gives in all 46 minutes; doubling this for the lowering aindcl lifting of one shift of men, and we have 92 minutes (1 hour and 32 minutes) for the VENTILATION OF MINES. 153 whole. and that without either danger or fatigue. So that for 200 men and 400 metres of depth, the ascent by ladders requires 6 hours; by hoisting, varying friom 1L to 4 hours; by the mal n-engine, only 1b hour. The fitting up of a man-engine is doubtless a considerable expense, but it is soon repaid by the time saved, and the prevention of muuscular fatigue of the miner. For further details respecting the construction and Aworking of manengines reference may be made to the followilng-named works, fronll which a part of the information here presented has been compiled: Burat's Materiel des Honlilleres; Portefeuille de Cocklerill; Zeitsclhrift des csterreichischen Ingenieur-Vereins, 10te Jahrgang; Annales des Travaux Publics de Belgique, vols. 4 and 6; Ainnales des MIines de France, 5me, vol. xv; Rtevue Universelle, vols. iv, v, vi, xiv, xvi. CHAPTERL XIII. VrENTILATION. Very few of the mines of the West are so deep and extensive as to require any elaborate and extensive contrivances for their proper ventilation. In most cases, their position and construction are such that a current of air circulates spontaneously through them by reason of one of the openings being at a greater altitulde than some other, as, for example, one or more shafts with tuunels leading to them from the hillside. If the air in the mine is warmer than that outside, it rises in the shaft, and is replaced by the influx of the colder air through the tunnel. But the conditions essential to ventilation in this way are not always found, and it becomes necessary to resort to artificial mneans to supply the miners at the extreme points of the nine with fresh air. In driving long tunnels, especially where powder is used, the, air is rapidly vTitiatedl, and soon becomes unfit to breathe. There are two ways illa which ventilation may be effected, either by drawingl the impure air out, or by forcing pure air in. A good example of the first-named method was presented at the Latrobe tunnel, Virginia City, which was driven for the greater part of the distance without a ventilating shaft, one ouly having been sunk not far from the entrance. Tin pipes were first, used to convey the air and were placed along tile top of the tunnel extending from a few yards back of the face to the bottom of the air-shaft. But it was found difficult to mrainltain a good draiught, and the metal pipe was replaced with one of wood, made of boards about eight inches wide, and rabbeted so as to form. tight joints. With this arrangement nlo difficulty was experienced; the heated air at the end of thle tunnel escaped constantly through this tube and rose in the shaft, while the pure air from the outside flowing in at the mouth of the tunlnel took its place. In this instance it was evident that the non-conducting quality of the wood prevented the air from becoming cooled in its passage before it reached thie shaft. The method of producing a draught by means of a fire or by connecting the ventilating pipes with the ash pit of the fulrnace fires is well'known and is often resorted to on a small scale in California. The only example of mlechanical ventilation worthy of special muention which came under the writer's observation in California was at the Princeton gold mine, Mariposa Estate. Foul air was generated to such ~an extent in the southern part of the mine that it could not be entered. A simple centrifugal fan-wheel, about ten feet in diameter and two feet 154 MECHANICAL APPLIANCES OF MINING. wide, was erected over the nearest shaft. This fan-wheel was not inclosed, but revolved between two vertical temporary walls of boards, thus leaving the arms and fans fully exposed to view. The mouth of the shaft was tightly closed, excepting two openings connected by box tubes with large openings in the walls of boards, around the axis of the fan-wheel. When this wheel was put in motion by a band from the engine, it produced a strong current of air up the shaft, and cleared the workings of foul air in a short time. It was evident that a much smaller blower would have answered the purpose. For forcing pure air into tunnels and drifts of slight extent an ordinary wind-sail or a faln-wheel driven by hand or attached to the horsewhim is usually employed; but these, of course, from their want of forcing power, are not very effective. The object in using them in most cases is not so much to supply pure air as to give a cooling current or blast of air near the workmen. In several of the mines upon the Comstock lode, the " Indiana Blowers Root's rotary compression blower, is used with great success in ventilating. Mr. James G. Fair, superintendent of the Hale and Noreross Silver Mlining Company in MIarchll, 1869, had the blower in constant use, day- and night, since its adoption by the company in August, 1868. Although of only medium size, it supplied sufficient airto enable them by the use of branch pipes and dampers to prospect simulltaneously at different depths, and at considerable distances apart upon the same level. It furnished air to two gangs of miniers in separate drifts on the 1,030-foot level, and partially ventilated the level 100 feet above that, and with but a portion of the power the blower could have utilized. The Potosi Company have had a No. 2 blower for ventilating the levels below the 900-foot station; and they have been successfully used upon the Yellow Jacket mine since the great fire. Mr. Winters, the superintendent, in August last, in a letter to the agents, said, " I have great pleasure iin stating that they work admirably. If we had been without them, it would have been quite impossible to work our mine since the great fire in this and the adjoining mines." This blower gives a " positive" or force-blast, taking in and forcing forward a definite quantity of air at each revolution. Its construction is shown by the figures annexed. Rooffs/ot, aryCompresioBowr-teio Root's Rotary Compression Blower-exterior. VENTILATION OF MINES. 155 The first figure shows the external form. of the case, and pulleys at each end for the reception of driving-belts. The cross-section of the interior shows the illlet and outlet and the form of the arlms or wings. The case is usually made of eastiron, with the cylindrical parts bored out, and the head-plates MM M11 faced off truly upon a boring- iil' Th imill, arranged for the purpose. i1]' The friction is confined to the journals and cog-wheels. The running, but move as closely to- s B -, gether as possible without being actually in cotacet. They are about two feet long and makee E froml 100 to 300 revolutions a minute. A omachine exhibited I I " iI ~' at the Paris Exposiation was saa id R to produce a pressure equal to oots Bloer coss seo one-third of an atmosphere, or five pounds to the square inch, when driven at the rate of 250 turns per inmute. lit the coal mines of Pennsylvanin muore and more attention is now given to ventilationl as Dot only the ordinary difficulties of working, but also the liability to accumulations of dangerous gases increase with the depth of the mines. The different systems of natural and artificial ventilation, including the use of the furnace, steam;jet, and blower, have been vigorously discussed during the past year or two by Messrs. Rothwell and Harden, mining engineers of Wilkesbarre, in the columns of the New York Engineering and Mining Journal. The latter gentlelnan.seemls to esteemn the furnace more highly than the former, who in most cases lprefers fans. The arguments on both sides were interesting and valuable; and those directed against the furnace were emphasized.shortly afterward by the terrible catastrophe at Avondale, where apparatus of this kind set fire to a column of gas and burned the brattice of the shaft land the breaker over it, closing the only entrance to thlee mine and sacrificing a laroge number of lives. A fan has been substituted for the furnace at Avondale; yet under some circumstances a fan is inferior. For instance, when a fan is disabled or interrupted its effect,ceases at once. Thus, at some critical moment in a mine, or in some very fiery mine, where every moment is a critical one, the fan ventilation might instantly and totally cease, while a furnace, though neglected or interrupted, would continue to act, though with diminishing effect, for hours.. The precaution of maintaining a! duplicate fan always in reserve is calculated to remove the objection. MECI-ANICAL VENTILATION OF MINES ABROAD. For the extensive collieries of Great Britain and the continent of Europe powerful means of ventilation are required, and the subject receives great attention among mining engineers and constructors. The miners not only have to contend with the air vitiated by their own respiration, by the animals employed, and by the lamps, but the coal beds themselves give off large volumes of deleterious gases, and the dreaded fire-damp, the collier's great destroyer. Coal mines therefore require more elaborate and costly preparations for ventilation than any other. The mean depth of the English coal mines is 180 metres; of those in Belgium, at Cllarleroi, 360 metres; at Centre, 350 metres; and at Mons, 416 metres. 156 MECHANICAL APPLIANCES OF MINING. A few years ago nearly all the important collieries of England were ventilated by Ineans of furnaces placed near or at the bottom of ventilhating shafts, by which the air was rarefied and made to ascend. In such furnaces, fromt ten to twenty tolls of coal were burned daily. This required large furnaces and costly excavations, and galleries of large size for the air-courses. In Belgiuml and France mnechanical ventilation has been carriecl to a great degree of perfection. Thlis systern is said to be well established by exl)erience as mLuch cheaper and less dangerous than the use of furnaces, and is gradually replacing the furnace ventilation. Mechanical ventilators may be grouped in three classes: 1, centrifugal ventilators, or fans; 2, rotary pumps, or force-blowers; 3, piston machines, with reciprocating motion. Ventilators of the first class are of great dimensions, capable of delivering imnmense volumnes of air. They have been in use for about thirty years, and have undclergone many changes and improvements. Like most other ventilators, they act by aspiration, producing to a certain extent throughout the mine a lower barometric pressure than is found in the external air. This depression varies in general fronm five to seven centimetres of water. Guibal's euntilactor.-Guibal's ventilator, after having undergone many * I.....b:.._......:..............a t s: eo n. Guibal's Ventilator-section. VENTILATION OF MINES. 157 changes and improvements through a series of years, is now most in favor. It is made with a diameter of 7 to 9 metres, and is inclosed for three quarters of its circumference. The other quarter has a lmovable valve, so that the size of the delivery openilg can be varied at will. The air of the mine is received by a central opening, of whichl the diameter is equal to that of the shaft, and it is thrown out through a vertical chilney, the sectional area of which increases as it ascends, in order that the current may enter the outer air with a progressively reduced velocity. These ventilators are also used to throw air into the mine by reversing the current. The construction shown in the section is that of the ventilator established by M. Guibal at the Blanzy minles. It has two chimneys, one for delivering the air froml the mine upward, and the other for a reverse movement wh-en it is required to take the air from the surface and force it downward into the mine. In this case a valve or door at the top of the chimnley closes the opening, and when the fan is used to throw the air out of the mine the reversed chimney is closed by a similar door. This form of ventilator was formerly made open without an envelope or outer case; but it was soon found that much of the power was lost by re-entering currents of air. In 1862, AM. Gnibal sent to the London Exhibition the plan of a ventilator capable of displacing 100 cubic metres of air per second. Tllis required a fan nine lmetres in diameter anlc four metres wide. Thel engineers of the Blanzy mines, guided by a long experience with Dunvergier's ventilator, have adopted a machine with the axis vertical. Tlhe fan turnt s in a pit lined w\vith masonry andI coveied over. The air is drawn in frioil below and is thrown out thlroughl an opening to a chimlney at the side. It is about 30 feet inl diameter, and is known as the Audemar ventilator. FAN-BLOWERS. To this same class of ventilators belong the great variety of the ordinarv fan-blowers, and it will be sufficient for the oljects of this ilotice to mention only one or two of these, which have been used to some extent in mining. Lloyd's noiseless.fic.-Lloyd's noiseless fian, anl end view of which is shown in the figure. consists of a hollow drum, made of two cones of thin metal, and divided radially by curved partitions, extending from,I lil Lloyd's Noiseless Fan. 158 MECHANICAL APPLIANCES OF MINING(. the axis of revolution to the periphery. Its construction n.uchl resetmbles that of Appold's pump. The air is tlaken in by openings at the centre arouncd the shaft, and discharged between the partitions at the circ;umference. It is nmade of various sizes, from thirteen inches to four feet in diameter; the smallest are run with the velocity of 1,800 to 2,000 feet per minute, and the largest 800 or 1,000. WVhen used as an aspirator in mines, the surrounding box is not required. Schiele's Jfan.- Sehiele's compounl d blowing fan consists of two fans resembling Lloyd's, and acting successively upon the same air. The first fan drives it into a chamber between the fais at a pressure of about six ounces; the second compresses the air still more, so that at the delivery pipe it has a pressure of about twelve ounces per square inch. A ventilator upon this principle was used in the ventilation of the Exposition building at Paris, 1867. It is well to note here that for the purposes of aspiration of air from mines, where great volunles of air are to be moved at a low velocity, and through large galleries and crifts, the large centrifugal blowers or fans al:re well adapted; but forfcing air in through narrow pipes or condluits, where large volrues cannot pass, velocity and pressure are required, and for this purpose the compression or force-blowers of the second class are preferable. ROTARY C1OMPRESSION VENTILATORS ABROAD. Of the second class, the rotary compression ventilators, Fabry's and Lemielle's appear to be the most used. Fabry's consists of two interlockiing wheels, with three arms, the extremities of which are in the form of a, cross, with epicycloidal arcs, the surfaces of which, coming in close proximity or contact with each other, carry forward a volume of air equal to the inclosed spaces at each revolution. These ventilators are generally lm.70 in diamneter, and from 2m'.00 to 31m.00 long. Lenmielle's ventilattor.-Lemielle's ventilator revolves horizontally. For 20 to 25 revolutions per minute, aind a delivery of 30 to 40 cubic metres of air a second, the diameter should be 7 Inetres and the height 5 metres. Cooke's ventilator. —Mr. Cooke, of England, has recently proposed a velltilator of the same class. It is described in " Engineering," from which I condense the following description: The machine is of a size suitable for a 1,000-feet pit, and it is intended to yield, per minutle. 180.000 cublic feet of air, w-ith an oxhaustion etqual to 3 inchles of wa'ter; or 150,000 cubic feet, wTith aln exhnustion of 4 inches; or 120,000 cubic feet if the dlrag is increased to 5 inchles of wa ter. It consists of two drunms, l, each 8 feet in dianleter alaid 16 feet ii lengtlh, these s drus beingo moulnted eccentrically on the shafts 1. The amnount of eccentricity of each drunl is 2 feet, alid each as it revolves thus moves in contact-or almhost in contact-witlh a cylindrical casiing, c, of 6 feet' / radius. The casings, c, are closed at the r K' 4 N e /, _ /| - ends by the brick walls whichi forin the side of the apparatus, these walls being coated with plaster over those portions ag ainst which the ends of the dlrums, C work, and bleing connlected att the top by the covering. The casinls are not coinplete cylinders, each beinr open for a portion of its circm-ference, c e. The air froml the ione is led to the aplparatuls by the slihaft, wliich conilmuiiceates with the Cooke's Ventilator. space surroundinlg the casings, and it is VENTILATION OF MINES. 159 drawn into these casings, and finally discharged at openings by the action of the revolvingr drums, a, in a manner wlich -w\e shall now proceed to explain. The portion of the casing left often is closed by a vibrating armi or "shutter," s, hnmg by the upper edge atj, anld the lower edge of wnhich is kept closely in contact with the surface of the revolving eccentric cylinder by means of all arm keyed upon a prolongation of the shaft i, beyond the side of the machine. Each arml is 6 feet long' between centers, this length corresponding to the distance between the center of the shaft, j, anld the center, m, from which the curve of the lower part of the shutter, j k, is struck. In fact the center of each arm agrees exactly in positioin with the center, m11, to which it corresponds. On one end of each of the main axles, b, is fixed a crank, each crank having a 2-foot throw, and the center of its crankpin exactly corresponding in position with the center of the eccentric idrumn on the same shaft. Each of these cranks is connected by a link to the end of the corresponding rocking arm, and as the length of this link is equal to the radius of the drnumr, a, added to the radius mn o, of the lower part of the corresponding shutter, j 7k, it follows that each shutter is kept in constant contact Avith the drum to which it belongs. The lower edge, k, of each shutter sweeps over a curved surface of plaster, e f, this plaster, which is held in a hollow casting as shown, enabling a sufficiently tight joint to be mrade very readily. The action of the apparatus, which we call best describe by considering the niotion of one driun oinly, is as follows: When the moving parts are in the position directly opposite to that shown in the section, the coniimlunication between the inlterior of the casing, c, and the space suirrounding it is closed by the shutter, j 7c; but as the drumn, a, moves round il the direction of the arrows, the lower end of the slhutter, j k, gradually aplproaches the shaft, b, and a space is thus opened between its lower edge, k7, and the edge, e, through which ILe air call enter the casing, c this openling reaching its maxinllul area when the parts are in the positions shown. As the dlrun continues its motion, the shutter, j kc returns a(galin toward the position, j kI, and the air which has entered the casing is swept round to the discharge opening, g. The curved surface, e f, is mnade of such length that the lower edge, k, of the shutter keeps in contact with it during the tinre that the point, p, of the druiln, a, (the point of greatest ecceintricity,) is passing between the points d and e of the circulferenrce of the casing —and in fact somlewihat longer —thus preventillg any back leakagie. The two drul-ls, a, re so connected to the engine as to be mioving always in contrary directions. One reason for this is, that the air contained between each cdruil anld the interior of its cylindler is nearly a complete crescent, and consequerntly munch smlaller at the horns than in the middle. By having a second drunl workiing at the horns when the first is -working at the middle of its crescenlt of air, the two drumin are made together to give ani equacble stream of air in the shaft. A second reason for a(dopting this plain is, that convenielnt sizes for mine vemntilators are apt to be too long, asrnd if the weight is to b)e divided tis plan acdmlits of thlle convenient dispositionl of the engine, while, at the samLe time, doublilng thle bearings of the imachinle. A third reason is, thart altholugh the dlrains are perfectly bala:nced ais respects their own rotation, there remrains the reciprocation of the shutters and their levers and cOlncrcting rods, whlich, instead of introducing vibration into the machine, are by this rne'aurs illade to collmpensate each other through the girders ulponl which they respectively act. A fourth reason, Ilot lulirimportant il large rnachines, is, that the shutter as adopted in the plan (thell simall weight of this shutter being as lanch as possible concentrated inear the axis, so as to assist its penldulous actiomn, cnd dirilisl as isnl ch a s possible the trav-el of its center of oscillation) has the pressure of the air ol o1ne sidle only, a'ld consequently lputs a certain strain nuponr its connlecting rod, wlich, by this duplicate arraenllger nt, exactly counlterbalanlces that uponi the connIectin rod of the other mnachine, the strainl of course passing throulogh the side rods from one drumn to the other. When the n-machine is not duplicated it is proposed to place a balance weight near the axis of the shutter, at the salnie time partially balancing the pressure of the air, and making the shutter vibrate mnore in harmlony with the revolutions of the drumn. The next thinlg to be observed is that the openinig onI the top of each mllachine is equal to the extremne opening of the shutter into the cylinder internally. The mlachine whose shutter is in this position is at its greatest work while the sllutter of the other machinie is closed, and consequently no work is for a nmomlent going on there. It will also be noticed that the openings which have been spokern of are Intch greater than half the area of thle shaft to which the machine is applied. This is to avoid giving tihe air a higher average velocity iii ally part of its passage throngh the machine than thlat prevailing in the shaft. The machine acting on the thick part of the crescent doing mulch inore than half the whole work then going on, the opening has been proportioned, so as to realize the required velocity. The shafts, b, are provided nit one end with cranIlks, which are coupled to a crank of equal throw fixed at the end of the cranlk shaft of a horizontal engine placed by the side of the apparatus. The mlnotion is thus communicated froml the engine to the drllns in the salnre nmannrer as thle coupled wheels of a locomotive are driven, 1a simple arrangement which will no doubt be found to work well. The arrangement also allows either 160 MECHANICAL APPLIANCES OF MINING. drum to ble discolnected, lwhen it requires to be stopped, without ulecessitating the continned stoppage of the other. This advantage is sufficient in fiery miines, at least, to justify the precaution.i We think that the particulars we have given of Mr. Cooke's ventilator will show that the machine possesses imauny features that render it entitled to the carefill attention of those interested in line ventilation. The apparatus consists of but few parts, andc those are all of silmple coustruction, and are slibjected to nothing more than very ordinary wear and tear. The eccentric drumls are of sheet iron,.:-inch thick, supported by cast-iron eccentrics, which also form the balance weights. The casiings in which the drums work are also of sheet iron ~-inch thickl stiffened by ribs; while the side walls of the apparatus are of brick, and halve east-iron columns built into thenm to support the pllnmer blocks. As the druims revolve barely in contact with the casing and flaps they will be subjected to little or no wear so long as the bearings of the shafts, &c., are kept properly adju lsted, and these bearings being all fully exposed to view there is no reason why they sholuld be neglected. Indeedcl, one of the great practical advanltages of the arrangement is that all the -wearing plarts are completely olpen for inspection. Upon the performance of this blower in model, "Engineering" remarks: This imodel represented, to the scale of 1 inch to the foot, the venltilator we illustrate, and it was testested aainst a 25-iichl Lloyd's fan, by elploying an enlgine to drive the model an11d fan alltrnately, full steam being admitted to the enlgines and tile boiler being kept blowing off in each case. Unler these circulmlstanlees the inaximuim pressure against whllicl tie fan. was found to leliver air wa'Tis equsal to 9~ inchlles of water, while Mr. Cooke's ventilator blew well against a p)ressure of 22 inlches, beyond which the engine power was isnsufficient to dri've it. In ianother elxperiment the model, although clriven thronligh a belt amnd gearing: was foundl to utilize 78 per cent. of the indicatedc power of ellgine lwhen exllausting aainst a drag' of 6 inches of water. This is a very high duty, all thilgs considered, but at the sanit time we see ino reason-judging froim the construction of the a)pparatus —why all eqiually goocl result should Lnot be obtained from the trial of tihe ilaclline on a larte scale. The flans which hiave beeIi alppliecl for ventilating purposes have been forulld to yield an effective duty of froum 40 to 55, or in some cases n1early 60 per cent. of the power applied; but tile efficienlcy, eveni of thie best failS, varies very materially at different speeds and unclder different circnumstances, and, imoreover, unless used on the duplex system —tlatt is, one for receiving and conildensilg the air delivered by anotller —they cannot be convenienltly worked a-rainst high pressures. Mr. Cooke's ventilator, ol thle other lhand, alppeiarls well aildaptedl for working against much hilgher pressures than are ever wainted for miie venlltilationl and \we believe that in a slightly modified forim it might be advaintageounsly emllloyedl for s-upplying blast to cupola furnaces alnld for similar lpurposes. Root's conmpression blower. —Root's compression rotary blowers, in use ill our 1mines, and already described, belong to this class, and for simplicity ancd effectiveness compare favorably with either of the above. Evrcard's blower.-Evrard's compression blower may also be noticed here. It is constructed upon the same principle as the rotary steamn-engine of Breval. Two cylinders of equal length. and whose radii are as two to one, revolve in contact, one rolling upon the other, except where two cycloidal indents in the slimaller cylinder receive in succession each of four projections or pallets upon the larger. Thirion's hydraulic pnresscure blower.-Of the third class —lmachines -with a reciprocating m loveme nt-Thirion's hy draulic pressure blowver is worthy of special mention; and this notice I extract firom the report of President Barnardl: * Still a third conipression ventilator apipeared ill the Exposition, which, for its sinlplicity and its originality, seems to imerit notice. It is called by tile exhibitor, Mr. ThliriOI of Mirecourt, Franlce, a machbiee soclaltce ci colomic d'cta,. but the water referred to ilL the name served no other plurpose lbut to pack the Imovillg lparts and(l prevent friction. The figure annexed will serve to renlder the constructionl intelligible. Three cylinders are here seen, side by side. The two lateral ones are the complressors, and the micddle one the reogulator. One of the compressors is shorwn in section. A is a cylinder of wood or sheet metal, as may l)e colnvenienlt, bolted to the base which sustains the wh-llole. WTithin this is anlother cylinder, and between the two is ain iimmlar space which imay be filled to anly level desired with water. The water level in the figure is showal at O. Between these two cylinders is suspended an inverted cylindcer,?iMachinery'aid Processes of the Incldustrial Arts, pp. 193-196. VENTILATION OF MINES. 161 or cylinder open downward but closed at top, which enlters the ainnular space between the two cylinders first naml-ed, without touching either. In the top of this suspended cylinder a-re two valves, E and E, which open inward. A cap is placed on the central _-.P~ m k.L Thirion's Hydraulic Pressure Blower. cylinder within, and in a valve-box beneath this are two other valves, F and F, which open outward as shown. From the closed space into which these valves open descends'a pipe D, which communicates beneath the base by means of the recurved and rising tube H, with the regulator. The action of the machine will now be easily understood, it being observed that the regulator. is constructed on the plan of the compressor so far as that the cylinder B, which is closed above and open below, descends into all annular space containing water, like the suspended cylinder of the compressor. The cylinder B, however, is not suspended, but is simply kept in an upright position by a guiding rod proceeding from the centre of its crown. It has also a scale pan above it to receive pressure weights, and should have a safety valve, though none is shown in the figure. The movable cylinder of the compressor is suspended frorn a crank or eccentric on the dlriving shaft of a prime mover. As in the revolution of the shaft the cylinder is lifted, air enters by the valves E, which spontaneously open. As the cylinder descends the valves E close, and the valves F are opened by the pressure of the contained air which is condensed by the force of the motor. The condensed air then filnds an escape through D and enters the regulator through H. At the top of H is a valve which is represented as raisedl thle ellterinl currents. Tile eylinder B rises to give roollm for tle entering air, the pressure remainingj constant and being dependent on the weight with which the scale pan is loaded. Tile second compressor acts alternately with the first; so that -a stream of air is constantly entering the reservoir froml one or the other. A tube P, from the centre of the regulator, descending below the base, conducts tle blast to the:11 II 162 MECHANICAL APPLIANCES OF MINING. point where it is needed, andcl here it is delivered through a tuyere, P. A siphon galnge, attached to this tuyere shows the pressure of the air -at, the efflux. Of colurse, as the pressure is illcreased, the level of the water within and without the movable cylinders, both of the compressors and of the regiulator, -will become unequsal; and the imaximlun pressure attainable will be only equal to the vertical height between the top of the fixed cylilnder A and the bottomi of the movable cylinder when at its highest point. If the water in A is in too great quantity to admcit of such a pressure it will run over until the pressure is attained. If it is in deficiency, the maxiimum cannot be attained, but the,air at soime pressure inferior to the maxilmum will begin to escape from beneath the bell. These statemllents are fiounded on the supposition that the suspended cylinder, or bell, divi(des the annllar space into which it enters equally. Greater pressure nmay be obtainecl by the use of a liquid heavier than water; and, for powerful blasts Mr. Thirion proposes to employ mercury. With water he obtains a pressure of ninetyfive celtimnetres, (about three feet,) or say a pound and a half to the square inch. Substituting mercury, there might be obtained, n ith half the difference of level, twothirds of an atnosi)here. The pressure of a pomd amidcl a half, however, is about four times that which is furnishedl by a good ventilating fan, and higher than is commonly used in cupola furllaces. This machine has four very decided recommendations. It works allnost without friction or leakage; the deterioration by wear is inappreciable; the perfect and exact regnlation of the pressure is easy; and finally, the excellence of its performance de — peals in no degree upon precision of worknlanship. It is a machine, therefor e, which is especially ada.pted to the exigencies of furnaces in new countries and among the mlloulitains, since it can be easily constructed on the spot, and will give no trouble in consequlence of derancgements. CHAPTERI XIV. SAFETY LAMI PS, AND FIR1ES IN M: INES. As connected witll the sul)ject of ventilation, thle followilng notices of the principles upon which safety hlmps depend for their efficacy, and of the construction of those most, used, have been I)repare: In the common Davl l:mllrtlhe flame is surrounded by a cylinlder of black iron-wire gauze, with 28 apertures to the linear inch. This cylinder is firmly set iltLa brass riln wlhi(h s(rews ul)on thle top of the oil vessel. The welglht of this oil vessel is held by threestout uprightl Awires, outside of the gauze cylinder, alid brought togetller at the top for the recepltion of the ring by whichll the whole can be'carried. Thle n)pper portion of thle wire-gauze cylinder is mande double to secure greater dubility under the, corroding eftects of the air oil the hot wire. The two Davy lampns fitst used in a codal minie are still in existence in the collection of the IMuseum of Practical Geology, London, and are described as of small size, xith. cylindlrical oil-vessels of copper. The wire-gal ze enveloes or cylilnders are of very fine brass wire, and the ]mesh is very snmall. Three iron-wire standardls extend from the oil vessel below to a- flat brass cap or roof, to which the carrying ring is attached'by a swivel joillt. The original safety lamp of Sir Hllumphrey I)avy is in the possessiol of the Royal Iiistitution. Varitlus modifications of the Davy lamp have been made from time to timen, and there is a, great variety of lamlps in use, but those best known, beside the simplle Davy, are the Stephenson, Clanny, Mueseler, and Boty. Stephenson's safety lamp was invented by the celebrated engineer George Stephen)son, at about tIle same time that Davy designed his. In this laml) the xwire-gaiize cylinl(er is lined with a close-fitting glass chimney. The air is adliitted below, tlhrough a nlumber of small holes in the brass ring. It has a cap of perforated sheet copper. It is considered sabfer thaln the common Davy lamp, since the gauze, being kept from contact with the flame by the glass lining, cannot become red hot. SAFETY LAMPS. 163 The Miners' safety laml, invented by Struve, of Sw.ansea, which has been extensively introduced in the fiery collieries of South WVales, is similar to the Davy lamp, differing chiefly in this, that the wire-gauze cylinder is expanded at the bottom and made longer, so as to reach halfway down the sides of the oil box and include half of it. This enlargement of the gauze cylinder at the base gives it a conical form and a much broader surface than at the top. The advantages of the construction are the free admission of air through the numerous meshes of the enlarged base, the greater cooling surface of the gauze, and less obstruction to the diffusion of the light downward and in other directions. In the Clanny lamp a part of the cylinder of wire gauze is replaced by a cylinder of thick glass, the object being to secure more light from -the flame than canll pass through the wire gauze in the usual construction. The glass cylinder has a larger diameter than the gauze cylinder,.and is supported in a frame made of two brass rings, one above and the other below, and united by six vertical wires. The wire-gauze cylinder is secured to the upper ring, and the air for the supply of the combustion enters through the gauze above the glass, and has to descend to -the wick. This construction does not give much more light than a conllmon Davy lamp, owing to the absorption of the light by the thick glass. Mueseler's safety lamp also has a thick glass cylinder over the light, with a conical gauze chimney above it. It is so constructed that the feed-air is made to descend along the inner surface of the glass, keeping it cool, before being deflected upon the flame. This lamp is much used in the collieries of Belgium and the north of France. Eloin's lamp has a short, thick glass cylinder around the flame, and the outer surface is curved, so as to diffuse the light. Instead of a wiregauze chimney, there is a brass tube covered with wire gauze at the top. The air enters through a short vertical wire-gauze cylinder, and is distributed upon the flame by an argand cap. Boty's lamp also has a short glass cylinder, but above it there is an ordinary gauze chimney. The air is admitted through a perforated copper ring placed a, little below the level of the flame. ILLU3IINATING POWPER OF SAFETY LAMPS. All safety lamps differ greatly in their illuminating power owing to their various forms and the positions of the parts, and to the varied conlitions under which the air for the support of the flame is admitted. It is estimated that it requires eight lamps of Davy's construction to give out as much light as a wax candle, six to the pound. Taking such a candle as a standard for comparison, the illuminating power of some of the principal lamps is indicated by the figures which follow, showing the number of lamps required to produce a light in each case equal to one candle.Davy7s lamp, with gauze........................8............ 8.00 Stephenson1 s lamp........................ —......... —--- ----- 18.50 Upton anqT Roberts............................ 24.50 Dr. Clanny's, (glass)............................... 4.25 AlMeseler's, (glass)............ - - - -- - - - - -- -........... 3.50 Waiish's lamp with gauze....2.75 Davy's lamp, withoUt gauze-............................ 2.5 -Common miner's candle, 30 to the pound...............:..... 2.00 * From Hunt's edition of Ure's Did'ti6:nay. 164 MECHANICAL APPLIANCES OF MINING. In order to prevent miners from opening their lamps, and thus bringing the naked flame in direct contact with the combustible gases, various plans have been devised, the most common being to lock the lamp by means of a screw attached to the body of the lamp, the point of which, may be made to enter and hold the brass ring by which the gauze cylinder is held to the oil vessel. This is done by a key which fits the squarehead of the screw. Lamps are also so made that the light is extinguished as soon as they are unscrewed, and before the body of the lamp and the protecting gauze are completely separated. iDubrulles' self-extinguishing lamp is contrived so that the wick is turned down within the tube as soon as the lamp and the wire-gauze cylinder are disconnected. LAMP UNLOCKED BY MAGNETISM. One of the methods recently proposed for so locking the wire-gauzecylinder to the body of the lamp that the miners cannot disconnect the two parts, consists in p)lacirg a spring' bolt or catch in the interior, without any opening or other means of reaching it from the outside. When the two parts are put together they cannot be separated by mechanical means without cutting into the outer casing. But these spring boltsmay be withdrawn by the attraction of a powerful magnet applied to the outside of the lamp. The efficacy of all safety lamps depends, as is generally known, upon the resistance offered by wire gauze to the passage of flame due to the cooling of the gases. Combustible gases pass freely through the meshes, and may ignite and burn inside of the gauze-cylinder, but ordinarily the temperature of the gauze does not become sufficiently raised to permit the flame to ignite the gas on the outside. Under some conditions, however, the gauze becomes red-hot, and the flame will then pass through.*: It has also been found by experiment (September, 1867) that nearly every lamp in use will explode a mixture of carburetted hydrogen gas and atmospheric air, if placed in a current of this mixture. In these experiments the gas was taken from a 9-inch pipe at the Oaks Colliery, England, where a, current of gas flows upward at the rate, of three and a quarter miles per hour. An ordinary Davy lamp, with the sheath outside, exploded in 31 seconds, and again in 7 seconds. With the sheath inside it fired the gas in 63 seconds. The Clanny exploded in 13 seconds; a Belgian lamp (Meuseler?) had the glass broken. at the end of 55 seconds; several Stephenson lamps gave different re — sults: the flame was extinguished in a few seconds, or continued burning for over a minute. Three of Morrison's lamps were tested, and were extinguished in 7, 5~, and 60 seconds, respectively, the velocity of the current of gas passing at the time being, according to an anemometer,, 700 feet per minute. These experiments, or the reports of them, are very unsatisfactory, inaslnuch as the composition of the gas is not stated, nor are details given of the maulner in which the lamps were exposed to its action. But similar experiments have been continued, from time to time, and one of the latest reports of them is herewith presented. The resmlts will be seen at a glance by examining.the table:t -.-:' ~It is the opinion of Robert Hunt, F. R. S., that the hypothesis of cooling will not explain the phenqoenon of non-transmission.of the flames.,He conceives the "impermneability of wire.ggaze to flame- to be due to a rep.ulsive powe'i established beteN een'the hlot metal andlt'he ignited gas, similar in character, altlonighdiffering in condition,: -jlat which prevails between water and a white-hot metal." t From the Loudomn L dhg Jopurnal, December 4, 1869. SAFETY LAMPS. 165 Experinments with mining lampls at Eppleton. Colliery, November 25, 1869.. No. Lamp used.' T Resl.lt. 1 Davy.-........-..-..S........ —------------- - 8 41 Exploded. Dlavy.. —S — -.- ---- ------ --------- 8 3 Exploded. 3 Stephenson's, (original).-......-...........8 2 Wenlt ont.... 4 Stephenson's S. W. C., (solid tube)............... -.............. 8 9 WVent out. 5 Steplhenson's S. W. C., (perforated) ----------- ----- 8 2 Went out..6 Stephenson's, (original).-.......... —--- ----—..- 8 2 Exploded.++ 7 Stephenson's S. WV. C., (perforated).-... —--—. -.... -. - 8 3 Went out. S Stephenson's, (original)..... —....-......5. —.. —- - - 8 5 Went out. ~ 9 Stephenson's, (original) ----------- ---— 5 —- - - 8 3 Went out. 1 Davy ---- --- --------------------- 11.3 2 Exploded. 2 Stephenson's, (original).....1..............1... 3 10.Wen.lt oult. 3 Stephenson's S. WV. C., (solid). 11.3 3. Still barning. 4 Stephenson's S. WV. C., (perforated).....-......... 11. 3 -..... Still burning. 5 Stephenson's S. WV. C., (perforated).. — -. —----------—. —- 11. 3 30 Out..6 Stephenson's S. W. C., (solid). - ----- 11. 3 4 O t. 7 Stephenson's S. WV. C., (perforated)...... --...-. 11. 3 3 Out. 8 Davy.11. 1. 3 Exploded. 9 Stelphenson's, (original). 11. 3 5 Ont.'10 Stephenson's, (ordinary). —......... —---. —.i.i.... — -. 11.3 5 Out. 11 Stephenson's S. W. C., (solid)................. 11. 3 6 Out. 12 Stephenson's, (ordinary).-.-.-.-.-.-... 11-. 3 8 Exploded. 13 Stephenson's S. W. C., (perforated).......... --—... 11.3 10 Out. 14 -Stephenson's S. TW. C., (solid)..... 11.3 30 Out. 15 Davy...........i-.... —... ——. —-- 11.3 9 Exploded. 16 Stephenson's S. W. C., (perforated) -- 11. 3 9 Out. 17 Stephenlsonl's S. WT. C., (perforated)...-......... - 11. 3 3 Exploded.ll 18 Stephenson's S. W. C., (perforated)..-........... 11; 3 4 Expllodedl. I9 Stephenson's S. V. C., (solid)...... 11.3 3 Out..20 Stephenson's S. r. C., (perforated). —-—.....-. —-—...... 11.3 5 Out. 1 Da-vy. ------------------- --------------------------------- 14. 3 2 Exploded.:2 Stephelnson's S. W. C., (solid)....-.-.-.-.......... —. 14. 3 18 Went out. 3 Stephenson's S. WT. C., (perforated) -............ 14. 3 7 Went out. 4 Stephenson's, (original)......-................. 14. 3 6 Went out. 5 Stephenson's S. TV. C., (solid)......... —....- 14.3 36 Went out. 6 Stephenson's, (original)................... - - 14. 3 60 W WVent outt. 7 Stephensol's S. W. C., (solid)..........-...-...... 14. 3 2 El xploded.*;-. 8 Stephenson's S. W. C., (solid).......................... 14. 3 17 [Went out. 9 Stephenson's. (solid) -------------------------- 14. 3 20 W ent out..10 Stephenson's, (solid) --------------------------------- --- 4. 3 60 Went out. 1 Davy.................... —..-.... 23 1 Exploded..2 Stephenson's S. W. C., (solid)........ —-.- - -...... 23 60 Wrent out. 3 Stephenson's S. WV. C., (perforated).-.....-....... 23 7 Went oit. -4 Stephenson's S. W. C., (original)......-........- - 23 19 Went out. * This lamp wa'is used in the years 1815 to 1835. f Made after the same principle as the above lamp. +Exploded throlllugh gauze not being in its place. ~ Glass cracled. IThis is the lamp left with Mr. Hann on September 30, and which was very inuchl onu of order. lT Not a distinct explosion —a double relport. - - ** Exploded through a broken glass. The results of the experiments will *be foun-d to correspond very nearly with those'obtained on Septemlber 30 last, (see Mining Journal, Oct. 16,) the Davy laimp havinrg explodedl, as before, with a speed of 8 feet per second. It will be seen that only the Davy and Stephensol lamps were tried, but the Stephenson lamps tried are divided into f)ur classes: 1. The original Stephenson lamp, which was in use from the year 1815 alp to the' year 1835. 2. The improved( Stephenson lamp then introduced. This lamp was only imnp-roved ain order to mnake it mIore iportable, the weight being considerably reduced, allnd perhhaps a little mlore light got, but it was not intended to alter the principle of the lamp:in any respect. It appears, however, that this was. done unintentionally to a certain:extent, as a close examination of the two lainmps, and a careful study of these valuable experiments, will clearly show. The original Stephenson lamp tried in the last ex1periments has a very short copper tube on the top of the glass, arnd this tube is only perforated at the top, and not at the sides, while the improved Stephenson has a tube 166' MECHANICAL APPLIANCES OF MINING. rather longer than-that of the old lamp, and this tube is perforated both at the top and sides; awld this slight difference in construction has been shown by these experiments to be of some importance. 3. The Stephenson lamp was tried Aith a. tube not perforated at the sides, thus restoring the lamnp very nearly to its present state. And, 4. The lamp -which was left with Mr. Hanir, described as an ordinary Stephenson, and stated to be very Imneh out of order. It will be seen that in the first series of experiments shown in the table the speed of the inflammable current was 8 feet per second, and the Davy lamp was readily exploded, but the other lamps were extillgnished with one exception when the galuze exploded, "through the ganuze not being in its place." In the second series of experiments a speed of 11.3 feet per second was used, llen the Davy, of course, exploded, and the Stephenson lamps stood the test, and, wihat ist remarkable, were not extinguished, but remained burning in some cases. But there is one exception to this, as the la-mlp described as the ordinary Stephenson (experilents No. 12 and No. 17) exploded, although the other Stephenson stood the test, and the cause of this apparent anomlaly appears to be obvious enough. In the third series of experiments a speed of 14.3 feet per second was used, and the trials varied from 2 up to 60 seconds, the results being that the Stephenson lamps weree extin gnuished with one exception, where " the la1mp exploded through a broken glass." In the fourth series of experimenits the speed employed was 23 feet per second, and the three Stephenson lamps experimented upon were simply extingiished. These -were the original Stephenson lamp, aind the improved lamp, one wTith a solid tube on the top of the glass, and another with a tu1be perforated at the sides as well as at the top. The experiments, on the whole, must be regarded as very satisfactor y, as they confirm in every essential particular those formerly mande on September 30, and the result. ought to inspire the public xwith confidence as to the safety of the Stephenson lamp ulnmder any circnumstances likely to occur in mines. The experilents, however, show that great caulntion and care ought to be used in the construction of those lamps, as a very slight variation in the form may interfere with the principle of the lanip. The copper tube referred to, which is placed oil the top of the glass, requires great care, and there is no doubt that it ought only to be perforated at the top; aind it (the copper tube) ought also to be very carefully fitted to the sides of the wire gauze anl the top of the same, so as to prevenlt any current passing between the glass cylinder and the wire gaunze. From these and other well-known facts, it will be seeln that safety lamps, in mines containing explosive gases, afford a relative security only. This wa9s, perhaps, never more strikingly (and harmlessly) shown than ini an incident which occurred some years ago, in Zwickau, S axony. A lecturer* had been explaining the principle of the safety lamp to a considerable aundience, and proposed to illustrate his remarks with an experiment. For this purpose he had prepared a simple apparatus, consisting of a large glass jar and a rnbber pipe -with a glass elbow at one end. The other end of the pipe was connected with a gas fixture; a safety la-mp was set insid. e the jar, and the bent glass nozzle was introduced to the bottom of the lamp. The lecturer remarked, that, upon turning on the gas, an. explosive mixture of carbnuretted hydrogen, and commonol air would be formed in the jar; the flame of the lamlp would be elongated, and a long blne tip would be seen; then the whole interior of the wirie-gauze cylincler would be filled with flalme; but, though the gauze lig'ht become red hot, the flame could not, in any case, strike through to the outside-all of which phenomena, positive andi negative, would be clearly visible through the transparent jar. The gas-cock was thereupon opened, but instead of the peaceful demonstration looked fori' a prompt contradiction of the theory was the result. The flame was conmmunlicated almost instantly to the gas outside of the lanmp. In some confusion, the lecturer repeated the experiment, but with the same result; and he finally gave it up, confessing his inability to explain the disappointment, except on the hypothesis of some unknown imperfection in the lamp. The occurrence made a good deal of stir, particularly as there are many coal mines in the Zwickau district troubled with fiery M ir. A. Mezger, mining engineer. SAFETY LAMPS. 167 gases, and at that time recent accidents had been occasioned by explosions in spite of safety lamlps. The test was therefore repeated, still more publicly, upon some sixty lamps of various patterns, and it was found th-at only the old-fashioned Davy, and one other, the narme of which escapes ns, would retain the flame. Those lamps were found to be particularly dangerous which possessed. separate openings below for the admission of air to support the flame. These experimlents indicate the same conclusion as was lately arrived at by English investigators, nalsmely, that the strength of the draught of inflammable gases through a safety lamp has much to do with the degree of its security. The Zwickau lamp may have been unusually faulty in construction, rather thain principle; but this fact, though it might lessen the importance of these special experiments, could not alter the general bearing of both practice and theory on the question of the safety of all lamps. The principle involved is that of the rapid conduction and radiation of heat by the wire of the gauze surrounding the flame. Before the burning gas can pass through the meshes, it is said, so munch of its heat will have been abstracted, and radiated away in all directions, that it will fall below the temperature of ignition or explosion. Now, this depends upon the amount of heat communicated to the wire in a given time. The wire may get hot faster than it can grow cool again, and if this increase of temperature is carried to a white heat, the gas outside will be set on fire. But the aimount of heat given to the wire in a certain time depends again on the amount of burning gas that passes through it in that time, and helnce it is clear that a strong current of gas may overheat the wire and cause an explosion. The Davy lamp is not con structed to favor a strong current. Indeed, one complaint of it has been the feebleness of the light, fromn insufficient air. It appears, however, that attempts to remedy this deficiency are fraught with peril. We desire to call the attention of engineers to the great simplicity and conclusiveness of the test above described, and to urge that it be at once applied to the lamps of every mine. There can be no harim in knowing whether the lamps will do whalt is claimed for them. It is true that colmmon illuminating gas forms with common air a more explosive mixture than does the fire-damp of mines; but the severity of this test ought to be nothing against it, so long as any lamp can be found to bear it. In the general dissatisfaction with the use of safety lamps, which spread through the Zwickau district after the experiments alluded to, a new and bold plan was suggested, and has been carried out in several.cases with the best success. This was nothing more nor less than to burn nalked lights in gsieat ntebers wherever inflammable gases made their,appearance. Somle of tIhe workings presented, under this system, an unwonted appearance. In one case, the fire-damp could be heard streaming out of the fissures of the coal, lwith that peculiar humming sound which the mainers know so well and fear so greatly; the innumerable lights carried each a long blue tip-the usual signal of danger-yet no harm occurred. The gases were quietly consuimed as fast as they entered the mine, aind the illumination was carefully kept up, night and day, Sundays and between shifts, that no opportunity was given for an accumulation of explosive material. Tihe great difficulty of this plan is its direct injurious effect on ventilationi. The stationary lights with which. the mine is crowded, in addition to those carried by tile workmen themselves, must necessarily use up a good deal of oxygen, and produce a good deal of carbonic acid. But this is an evil which can be combated in other ways and, at all 168 MECHANICAL APPLIANCES OF MINING. events, it is preferable to the danger of explosion. Perhaps it might be an improvement to use safety lamlps instead of naked lights, hanging them in great numbers along the walls, so as to secure the complete, quiet combustion of the gas. But it must be confessed that, even under circumstances of the greatest danger, the naked lights have done very well, and no accident, so far as we are aware, has ever resulted from their use in this way. Propositions have been made to explode the accumulated gas in workings before the workmen are allowed to enter it. In a rude way, this has frequently'been done in fiery mines; and to remove all personal danger, it is now suggested that the explosion be effected by means of a battery. But this whole system of allowing the fire-damp to accumulate while the workmen are absent, and then firing it off all at once, strikes us as much inferior to the simple expedient of burning it gradually, as above described. FIRES IN MINES, AND THE MEANS OF EXTINGUISHING THEM. In spite of all precautions in the way of proper ventilation and the careful use of safety lamps, fires will sometimes occur, as many mining communities have had terrible opportunities of knowing. The methods employed for extinguishing them are therefore worthy of notice. On this subject I cannot do better than quote the excellent essay of Mr. IR. P. Rothwell, of 7Vilkesbarre, Pennsylvania, which appeared last summer in the New York Engineering and Mining Journal: Taking account of the nature of the mineral, we are not surprised that fires should be nluch more frequent and dangerous in coal than in ore mines; they are, however, by no means confined to coal or lignite deposits, but may and (do occur in all kinds of underground workings where timber is used. In the great majority of cases fires originate, below as above ground, through carelessness or imprudence. A mliner will lean his lighted candle or lamp in such a position that it can ignite a prop or other piece of timber. Such appears to have been the case in the recent disastrous fire in the Crown Point, Kentuck, and Yellow Jacket mines. The careless or imprudent hanging of a grate or fire-pot near the coal at the foot of our downcast shafts or slopes (where it is placed in winter to prevent the pumps and rods from being covered with ice) has been the cause of fires in several of our anthracite mines. Ignoramnce of, or inattention to, the proper manner of constrnuctinlg ventilating furnaces has also been a freqtlent cause of fires in. coal mines, but probably the imost fruitful cause of these disasters is the ignition of fire-damp, or carbureted hydrogen in coal mines; the ignition first produces explosion, and in mines yielding an inflammable coal it frequently ignites the fine particles blown about in a burning atmosphere, and these communicate the fire to the solid coal of the pillars; or the gas may continue to burn at some "blower" till it has ignited the coal in which the fissure or vent occurs. These so-called " accidents' are generally due to carelessness in the use of *'open" 1 lights, or in the opening of safety lamps in places where the gas exists in quantity. The practice of blasting in coal mines, which produces large quantities of the dangerous gas, has also caused a great number of deplorable explosions and fires; and the question of substituting some other ageint, such as water, wedges, &c., for powder in mines of this kind, is now receiving much attention amiong European mining enlgineers. "Fiery" mines, such as those ill the Richmond (Virginia) bituminous basin, would be greatly benefited by the successfil substitution of a safer agent for the powder now used, where rock or hard coal has to be mined. In our anthracite mines the hardness of the coal Awould render the use of powder more necessary, -while the smaller quantity of fire-clamp found in it would, a.t the same time, make tl.e substitution of a safer agent less desirable. The exercise of greater vigilance in the inspection and use of safety lamps wouldl, dcoultless, greatly diminish the unlumber of explosions and fires in coal mines. Many bituminous coals, and bituminous shales w-hich are found among the coal beds, are, under certain circumstances, sublject to " spontaneous comnbustion." This always occurs where the coal or shale is crushed in a confined space with an exceedingly feeble ventilation; indeed, spontaneous heating of the coal, accompanied as it is by an abundant production of carbonic-acid gas, was generally attributed to the decolmposition of iron p}yrites (sulphuret of iron) under the influence of the moisture in the air, and a circulation of air so languid as inot to dissipate the heat generated, while sufficient to EXTINGUISHING FIRES IN MINES. 169 supply the oxygen necessary to support combustion. It has, however, been observed that the coals producing the greatest quantity of pyrites are not always the most subject to heat spontaneously, while it has also been noticed that the most inflammable coals are those containing the largest proportions of oxygen; it has, consequently, been suggested that the more probable cause of spontaneous combustion may be the combin.ation of oxygen with the carbon, under the influence of mlloisture, andl which is accompalnied by the generation of carbonic acid and a considerable amount of heat. In the coal mines of Silesia, where cases of spontaneous combustion are of frequent occurrence, numerous observations have denm-onstrated that this class of accidents need not be feared where the "roof" of the vein is either sandstone or conglomerate, nor near the outcrop, whatever the nature of the top rock may be; on the other hand, beds worked at a considerable depth, or even when moderately near the surface, but covered by a shale capable of being softened by moisture, are the most liable to spontaneous combustion. It was long considered in Silesia that the only means of preventing fires from this cause, consisted in sending all the fine coal," " waste," or " gob," out to the surface. This was often impracticable, expensive, and not always effect-ual; hence other means of attaining the same end were sought for. Since it is well knlown. that combustion cannot exist when deprived of oxygen or air, one means of preventing spontaneous combustion consisted in isolating the working places, or goaf, by means of a heavy dry wall, or by two parallel -walls filled in between with clay or other material packed hard, and sometimes a heavy pillar of coal was left for the same purpose. In each case, however, the. weight of the superincumbent rocks almost invariably crushes the walls or pillars, and produces cracks or fissures, through which air, sufficient to sustain the slow combustion of the coal, call pass. This method has been employed with greater or less success in some of the mines in the centre of France, and in the thick seanm of Staffordshire. It is evident that whlln used the greatest possible care must be taken to keep the fissures closed, -which are found friom time to time, so as to seal hermetically the space inclosed. But besides the practical difficulty in effecting this, the fact that these inclosed spaces generally fill with fire-damp, and therefore forln veritable magazines of a substance far 1more dangerous than powder, and which, through the crushing of a wall or pillar, or the fall of a portion of the roof; may at any luorment be brought in contact with the lights of the men working in fancied security in the neighboring roads or chamblers, is a sufficient reason for condemningl so dangerous a systeml as that of isolation of the " goaves" by 1" pack walls." The spontaneous heating of coal is so slowr a process that the increment of temperature is easily carried off by a moderately rapid current of air; we can thus prevent the temperature firom ever rising to the point of ignition, by simply ventilating the " goalves;" this, then, is the exact opposite of the last mlethod, and though much safer and fully as practical, yet very serious objections can be made to it. It is all but impossible, owing to falls, &c., to keep the' goaves " sufficiently open to maintain the necessary circulation of air, and the expense of clearing up falls and opening the old workings, where obstructed, is so great as to Tender this Inethod impracticable in many cases. The systemn is, howeven', mlore or less successfully used in many mining districts in England, Silesia, &c. There now remllains but one other method to descri)be, and it is by far the safest and 1most efficient in the prevention of danger by spontaneous combustion. It consists in filliing or packing witll earth and other material sent down from the surface the spaces from which the coal has been removed, and which the waste of the rminle does ilot fill. This method, though somewhat expensive inL large seanms which mIake but little waste, is assuredly the most effectual remedy, since it not only prevents the admlission of air to the old workings, and therefore does away with the expense of ventilating thenm, but it, prevents the falls of the roof, in which "'I)lowers" are frequently opened, and rendclrs ilpossible any caccumulation of fire-damp, which is the great source of danger in the method of isolation by pack-walls, &c. Thus tliis mlethocl not only procures perfect imlnnnnity froim danller by spoltaneous combustlion, but the systemn of miining of awhich it is the principal feature enables us to obtailm all the coal of the vein. It is, therefore, not only the safest, but also, as regards the amount of coal obtained, the most econolical, method no-w in use, and it is deservedly popular in. Europe, aind more especially in France, Belgium, anld Germany, where it has been employed for a number of years, and lias now talken the place of every other system in.imost of the coal mines. Whatever precautions may lhave b)eetl talken to prevent fires, yet the carelessness, ignorance, and som1etimes the nmalice of imenl are causes which cannot always be effectually guarded against; hence we must be prepared to mieet thie dalnger of fire when it occurs, and to apply p1omnlptly the umost suitable mealns for its extinction. When a fire originates in coal or timlber, every effort should -be immueddiatcly made to extinguish it by throwing water on it either with buckets, or, better, with a fire engine; or where practicable, by tapping the cohlunn-pipe of the pump and leading the water through hose to the seat of the conflagration. In some cases the use of portable "fire extinguishers," (which generate carbonic acid gas,) such as are now found in every villa.1ge of the land, may prove of great service. If the fire originates by the ignition 170 MECIIANICAL APPLIANCES OF MINING. of a blower of fire-damp, efforts should be made with wet cloth, water, &c., to put out the flame; in some cases where these mealns failed, the flame has been extinguished by the concussion of the air, caused by discharging a cannon in the gallery where tihe fire exists. When the coal suLrrounding the " blowverl" has already become ignitedit i ill immediately re-ignite the fire-damp; so that this method canll only be applied either where the lblower is in- rock or where it has 110ot had time to thoroughly ignlite the coal. While these means are being applied, preparation should be made for erecting stoppings or dams, in view of the failure to extinguish the fire by the direct mIeans; yet these shoul-dl not be abandoned till there is no further possibility of success. When it is no longer possible to approach the fire near enough to throw water on it-that is, when the fire call no longer be kept under control-it becomes necessary to resort to other methods of extinction, viz: By isolating the part of the mine onl fire, and thenI applying extinguishing agents to the part inclosed. When thlis ftils or becoles impiracticatble, there remlains but one other method, viz: By closing the entire mine, and applying the samle extinguishing agents. These agents are water, carbonic acid, and nitrogen gases, steam, or any other gas incapable of sustaining combustion; those mlentioned being adopted on account of their effectiveness and small cost. The isolation of a fire in a mine is effected by constructinlg walls or stoppings across all the galleries or other openings which connect this p.ortion with tle remainder of the mine. These stoppings are sometimes walls of brick or masonry, varying in thickness fro-m twelve inches to six or eight feet; at other times two lighter parallel walls are built, and a current of air allowed to circulate between them in order to keep the inner wall cool, or else the space betw veen the walls is filled inh with clay and mlinewaste; while still another method. is to make a stopping, several yardls in thicklness, entirely of clay, wAaste, &c. Iin cases Twiere it can be done without danger, a timber stopping or even a simple board bratticing can be adopted; the kind of stopping as well as its strength will depend onl the position of the fire, its extent, the presence or absence of fire-damp, whether the stopping is intended to dlain back water or not, and suchr like considlerations, which iullder the enunciations of fixed dimension, are impracticable. The esselntial in every case is that the stopping should be air-tig1ht, and that it should be cornstruccted with the least possible delay, and at such a distance from the fire as to allow time for its completion, before the smoke arid irrespirable gases produced by the fire caLn prevent the men froml working. Notwithstanding that the ventilation of the part on fire has been reduced to a minimum by the erection of temporary bratticing, &c., yet the combustion of the coal and wood produces sulch enormous volumes of irrespirable gases that the work of building tihe stoppings is ole of great difficulty and danger, more particularly in mines proclucing fire-danmp, where the danger froml explosion is still greater than that fromr the gaseous products of combustion. It is evident that the stoppings can be constructed with least difficulty by commencillg witll those on the "outside" of the fire, or the side frorm which the air plroceeds to the fire, and afterward building those "inside" the fire, or where the air conmes froom the fire; yet in mines yielding fire-damp this mlethod.of proceeding is attended witlr great danger; the fire-damp mixing with the air confined betweenl the stopping and the fire makes ani explosive coumpound, which is carried forward toward tire fire, -rwhere it ignites, and thoulgh it umay not ecause a fatal accident, yet it allost invariably throws clown the stoppings by which it was soughrt to isolate the fires. As fromr one-tenth to one-seventh of its volume of carbonic acid, added to an explosive mixture of air and fire-damnp, renders the latter entirely inexplosive,(a larger quantity renders it incapable of sustaining combustion,) and as the products of coilbustilo n are carbonlic acid and ilitro gell it follows that by closing first the galleries onl the side toward which the air from the fire goes, we prevent the da'nger of explosion by mixing carbonic acid with the air contained betweein tile stopping and the fire, and by throwing the smoke and irrespirable gases back or the fire, Awe oo far toward extinguishing it. It is true it is a matter of great dainger and difficulty to build stoppings between a fire andcl the " returns," but by the use of temporary bratticing and by commencing at a sufficient distance from the fire, it is often practicable, amud it is always desirtable. Where it is impossible to build the stoppings in this order then.l whein practicable, it wou-ld be advantageous to inject carbonic acid gas, or choke-dlamp, (through a pipe in thie stopping,) from the moment the latter comes near completion, so that the air contained between the stopping and the fire may not becoule explosive. We speak, of course, of mines yielding fire-danmp. Where carbonic acid is not available, it will sometimes be possible to inject steat, whllich will not only deadcen the fire, but wvill, at least, diminish the intensity of the explosiolls. The stoppings completed- and where there is no danger from explosion or need of inundating with water the part on fire, there is no necessity for makilng them heavywe proceed to fill the part inclosed withr carbonic acid gas, with clhoke-damp, with steam, or with water. In the first case the carbonic acid can be malnufactured either cI__* ~ N (i'"{'~~ it GoldlswortLhy Gurney's apparatus for manufacturifng After-damp, 1849. A.-Furnace. 1B.-Water-tank. C.-Downcast stopping. D. —Ulcast stopping. E, 2, E.-Three steam jets. F, F.-C-alle'ies from shaftto shaft. 172 MECHANICAL APPLIANCES OF MINING. pure, or nearly so, by the use of any strong acid, such as snlphl ric or nmlriatic acid and chalk, or limestone, or any of the carbonates of low price and easily decomposed. This gas is easiest prepared in a lead vessel, which is not attacked by tile acid. Where the space to be filled is not great, some of the numerous patent fire-extinguishers might be found of service, as being quickly and easily brought into action. These methods have the advantage of supplying the gas at a low temperature, and thereby facilitating the cooling of the rocks after the flalme is extinguished. If the circumstances are such as to make the use of choke-damp-that is, a mixture of carbonic acid and nitrogen-advisable, it can be produced in one of the furnaces of which drawings and particulars are given below. In either case, as carbonic acid and choke-damlp are both heavier than air, it follows that the tube through which we admit these gases should be at the lowest, and that through which the'air from the.inclosecl space is allowed exit should be at the highest attainable point of the isolated workings, and the admission of the gases should be c:ontinue till it is evident they have completely filled these works. This is easily proved by their instantly extinguishing lamps, burning tow, &c., at the outlet tube. The tubes should then be closed, leaving only a siphon or water-gange to mark the difference in pressure between the inside and outside of the stoppings, and a place for the introduction of a thermometer used to note the variations in temperature, so as to know when it will be safe to open the stoppings. The greatest care should be taken to' keep the stoppings air-tight; they shonuld be frequlently inspected, and where from any reason it is found desirable to " drown out " or inundate the part on fire, they should have a thickness proportionate to'the head of watter they will have to retain. When the fire has assumed greater dimensions, or when its position is such that it becomes dangerous or impossible to confine it by stoppings such as we have described, it becomes necessary to abandon the entire mine and to resort to closing the shafts. Even when it is decided to inndate the mine, it is aliways advisable to close the pit, whether the mine produce carburetted hydrogen (fire-damp) or not, since by so doing e dealen, at least, the combustion, cand prevenlt, in a great measure, the damage always caused by the high temperature produced by a ralpid comb-ustion,. The shaft should, therefore, be immediately closed hermetically, provision being made for open-. ings through -which a registering thermnometer can be introdulced, and a bent pipe, or.siphon, containing water, to show the pressure behind the stoppilng, andl prevent its becoming excessive, while at the same time it prevents the admission of fresh air. The closing of the shaft may be effected by hanging heavy pieces of timber, by means of chains, somne distance down the shaft. On the platform thus made clay is thrown, and packs itself by the force of the fall, thus rendering the stopping perfectly air-tight. The tubes above mentioned should be inserted, andt one siphon should be so arranged as to allow the water to flow down the shaft, instead of' accumulating above the stopping. Wh.ere the pit is divided into a number of compartments, it be-comes difficult to close it perfectly in this way. The mouth of the pit is then covered over with planks or iron doors, and clay, sand, &c., packed on this, every crevice being.carefully closed. Great attention nmst be paid to this, more particularly in the case where it is desired to "'smother out" the fire with.out the injection of steam or carbonic acid, otherwise a quantity of air may enter, which, tllough inslfficiet to maintain an active combustion, mayv yet suffice to support a slow fire, or, at least, greatly increase the time necessary for its complete extinction. Where the mine does not lroduce fire-damp, there is no great danger in closing the pit, but if that gas is givent off in any considerable quantity, the closing of the pit is "sometimes attended' writh great dlallger, there being a, certain time after the closing when the quantity of atmospheric air is sufficient to make an explosive mixture with the gas from the mine. After a tilne, the quantity of air, or rather oxygen, is diminished by that constlned by the fire itself, and the incombustible gases produced by the ~combustion, mixing.with the fire and fire-damp, soon render the compound inexplosive. In such mines it is highly desirable to inject steam alone, ol, better, steam and carbonic acid, into the downcast from the earliest practicable moment, so as thereby to diminish, as far as possible, the chance of explosion during the operation of closing; and it should continue to be injected after the stopping is muade till the mine is completely filled, which can be known by the air issuing from the pllast exting'luishing a lighted lamp, &c. It is almost needless to add, that great care should be taken, and no open lights allowed near the shaft when there is any possibility of fire-damp existing in dangerous quantity. If the mine does not prloduce that gas, the immediate admission of choke damp is not so necessary, though it is always desirable as checking'the spreading of the fire. As the majority of fires occur fiom explosions of fire-damp, it follows that in most cases the air doors, bratticing, and other divisions necessary to guide the air current through the mine, are destroyed. It is then difficult to ascertain if the carbonic acid has gone into every part of the mine, or whether a large amount of air may not yet remain in the workings; this should be carefully considered in decidcling on the means to be adopted to extinguish the fire, andclalsoin fixing on the time for reopening the -pit. Not a few of our fatal accidents occurring from explosions were caused by re EXTINGUISHING FIRES IN MINES. 173 opening the mine too soon, or before the coal had time to cool down below the temperature at which it will ignite. In some cases, it may even be considered safest and most economical to fill the mine with water. This decision must be taken only after a careful consideration of the position of the fire, the amount of water needed to fill the works to the depth required, the time necessary to pump in that water, the nature. of the roof and coal in the works, and the effect which a longer or shorter inundation would have on themn, the facility for getting the water out, &c. The inundation of a mine is always an expensive expedient, and should only be adopted as a last resort; yet there are cases where it is undoubtedly the best mnethod to adopt. Each case requires a special study, and the method which mightl be the most suitable in one may not be adapted to another. The great sources of expense in inundating a mine are the damage caused by the water remaining for any length of time in the works (with certain kinds of rocks-some slates and fire-clays especially,) the falls of roof, causing delay and expense, anli the delay and cost of filling with and pumping out the water.. And in coal subject to spontaneous combustion it not unfrequently happens that when the water has been pumped out, the wetting of the " gob," or " waste," causes it to heat, and even to ignite, before the ventilation can be fully re-established. Every other means should in general be tried before inundating the mine, and the most efficient of these various means are the introduction of steam, carbonic acid, (choke-damlp,) and after-damp, which is a mixture of nitrogen and carbonic acid. Steam is available at almost every mine, and is easily applied; it should be carried in pipes, and discharged as near the seat.of the fire as possible, in order to prevent its condensation; it is a very efficient extinguishing agent, and from the facility with which it can be employed, it is now commencing to be much used; in many cases, a rubber hose, made especially for a steam hose, is all that is required to carry it for several hundred feet, and it will last as long as the occasion requires in most cases. The greatest disadvantage in the use of steam is its energetic action on some rocks, causing them to disintegrate and'" fall;" but where the roof is such that it is not materially injured by stealn, this is one of the most convenient, and it is always one of the most effective extinguishing agents we can use. Its action is limited to the expulsion of the air, and as it maintains a high temperature we are generally obliged to inject water, in order to cool the rocks sufficiently to allow the men to work, and also to prevent any possibility of reignition. The following example of its application will prove instructive: In 1857, at the St. Mathew mine, near St. Etienne, France, steam was injected after the mine had been on fire for eight days; this was continued for seventy hours, after which cold water was injected for three days, in order to cool the sides of the shaft, galleries, &c., previous to descending into the mine. The pit was then opened, and a. current of air circulated while the men went down. After two days, however, the: mine again caught fire, and it became again necessary to close the pit. Steam was then injected during twenty-four hours, and, after an intermission of eighteen hours, cold water was injected for twelve hours. The fire broke out a, third tinm- and steam was admitted for eleven hours, then cold water, after which the men were enabled to enter, and extinguish the fire completely by throwing water on it. I believe the same process was employed at the Yellow Jacket and Kentuck thines, on the Comstock lode,. which were on fire a few months ago. The application of carbonic acid or choke-damp and after-damp is more complicated than that of steam, since the materials for its manufacture are not often on hand. The most usual method of manufacturing carbonic acid is bV means of chalk or limestone, or any cheap carbonate easily decomposed, treated with one of the cheaper acids-as sulphuric, nitric, or hydrochloric. The gas produced in this way has the advantage of possessing a low temperature; it not only extinguishes the fire but ten:is to cool the rocks to a point below the temperature necessary for ignition. Portable machines, known as "tire extinguishers," are convenient means of manufacturing this gas where the quantity required is not very great, and they are to be found everywhere, at a small cost, and are always ready for use. Where the quantity of gas required is very large, as, for example, in filling a mine, one of the cheapest and most convenient methods of producilg it is by the combustion of coke or charcoal in a furnace of suitable form, and, as it was the means adopted in the first a,qpplication of'" after-dalmp' or carbonic acid to the extinguishing of fires in mines, we will devote some space to it, especially as the credit of the invention is commonly misapplied. The first application was made by M. Jules Letoret, in Belgium, in the year 1844. Five years later (1849) we find the same principle applied in England by Goldsworthy Gurney, who takes credit himself for the invention, and is even at the present time credited with it by nearly all the English engineers. It is scarcely possible that Mr. Gurney could have been ignorant of, M.: Letoret's invention, for we find him perfectly "posted" on the application of his steam jet in the Belgian mines, about the same time. On the 15th of February, 1844, a fire occurred from an explosion of fire-damp in the No. 2 shaft, Agrappe colliery, near Mons, in Belgium; the pit was 1,171 feet deep, three veins at different levels being worked. Efforts were made to extinguish the fire by 174 MECHANICAL APPLIANCES OF MINING. throwing water on it; but it had alreadly made too great progress, the frequent ex plosions of fire-damp having become very dangerous. It wras then decided to reverse the ventilating current in order to prevent the fire from destroying the pumps. M. Jules Letoret then prepared to introduce carbonic acid into tile works, that gas having, as we have already statecl, the property of rendering harmless anl explosive mixture of carbureted hydrogen and air, if only added to it in the proportion of one-tenth to one-seventh. Several experiments were made for the manufacture and introduction of this gas-the first on the 17th of February, 1844. The effect of the gas was to reduce the number and violence of the explosions, but the fire still continued to burn at the foot of the shaft; the pit was not perfectly closed at the time. On the 23d of February M. Letoret built a furn1ace, intended to produce carbonic acid, in a continuous nmanner, from the combustion of coke; the shaft was closed hermetically, leaving only openings for tile introduction and outlet of tire products of combustion. This apparatus is shown in tile accompanying figure, and is of so simple a construction as to require but little explanation. The furnace was chargedwith burning coke and charcoal to the depth of 17 inches, that depth being found sufficient ~1~ d = to consume all the oxygenl in the air passing through. the fire, and to produce carbonic acid and nitrogen, (a greater depth of fire will produLice at the same tinme carbonic oxide;) and as tbis 0k e hL g fgas issued from the furnace at a high temperature the reservoir of water, h, was nllsertedl throngh the stopping, so that the gases might be cooltl ind prevent any chanllce of ignitinIg the woodwork of tile shaft. When Shax the apparl''atus was set to work on tile 24th of February, thle fire wias visible at Letoret's Ftrhnace for manuactuig Aft 1 144 t fo)ot of the shaft; on tile Letoret's Furnace for manufacturing After-1damp1, 1644. 25th the flamnes and explosiolls h1tld ceased; the introa.-Ash-pit. d.-Fire-place. c.-Pipes carrying off tire flanle. e. —trrtio d of' fser-d inp Pipe ca.rrcying oas into the pit f. g.-Pipe adnittnIo water. t-Iron bars supporting e.. —Iron flooring covered with soil.. was tllen stopped, and fresh air was allohwed to enter the mine; but onl descending into tle nlie a larlte ire wavas discovered, quite red, but with little flaule. The Aork of clearing out tle gallery leading to it was coinmencel, in orler to be able to throw water on the fire; buIt the baromneter riclicating a diminishilng atmospheric pressure, the fear of fresh discharges of ca rbureted hyClrogen induced the abandonment of th mitrine into which carbonic acid was agail introduced. On tie'2 6th, the flame and explosions having agaliln ceased, fresh air was readmitted, and on e-Ltering the mine water swas thrown otn the fire by imaltns of fiire-engines; tilnbers were set, thoullh witll clifficulty, on account; of the 111ih telllerature. and because the rocks, decomposedl by heat, disil:tegrated and fell whenll water was applied. This work -was continued to the 3d of March, when the firte xvas enltirely extilnguished aLnd the rocks cooled doxwn. The roof hacld fallen to thile depth of 22 feet. Thus a fire which had threatened to destroy tile mine, or at least to prevellt its working for months or years, was completely extinguished in the course of ten drays. The above particulars, taken from a, " Menloire " by M. Jottrald, in thle "Annllales des Travaux Publiques de Belgiqiue," though very brief, are yet sufficient to show the manner of operating in sucll cases, and to establish M. Letoret's claimn of invention of this method of extinguishing fires in inines. I shall now describe Mr. Gurney's filrnace anld nimanner of, operating. The full particulars are given in a pa rliamentary report on accidents in coal mines, 1849. Tire drawing on page 641 shows tlre arrangenent of' the apparattus. The filrnace was four feet square, the ash-pit air-tioht, andl the pipe leatilng fi'om it thirteen inches in diamrneter.- This pipe plunged into a tank of water, B. In order to cool the gts before entering the mine the air was drawn throllgh the fire aurd forced into thIe pit by means of three steaml jets, E E E, working with a pressure of froul thirty to forty pounds of steamnitl the'oilers. The fire which called.this apparatus into use occurred in the Astley pit, (390 feet dcleep,) near Manchester, England, on the 2d April, 1849. The nine being very fiery, EXTINGUISHING FIRES IN MINES. 175 there were great fears of an explosion. The engineer in charge, Mr. Darlington, wrote to Mr. Gurney —well known from his application of the steam jet to mine ventilationto know if there was any nmeans of "' draiwing fire-damp out of a closed mine without letting air in." Mr. Gurney, in lis evidence before the parliamentary committee above referred to, says: " An idea struck me, (from experiments I had made in passing air through a, closed vessel running through the fire, where I found the whole of the oxygen to be combined, and nothing going out but nitrogen and carbonic acid,) if we made a large furnace and connected with the ash-pit, perfectly air tight, a cylinder, and put a steam jet in the cylinder, we might draw air through the fire and drive nitrogen into the mine." Mr. Gurney found that passing air through a fire 18 inches deep would consunme the whole of the oxygen of the air; M. Letoret lound 17 inches sufficient. It is evidently desirable that the depth of the fire should not mluch exceedl that necessary to effect the complete combustion of the oxygen and the formation of carbonic acid; for when it is increased a portion of the carbonic acid takes up another equivalent of carbon and forms carbonic oxide, a gas which, though incapable of sustaining combustion, being itself combustible, would not act as energetically as the carbonic acid or nitrogen in preventing explosion or combustion. After injecting this after-damp (mixture of about four-fifths nitrogen and one-fifth carbonic acid) into the pit for two hours, a little white cloud coming out of the upeast showed that the mine was full, which fact was easily proved by the gas coming out of the pit extinguishing burning tow, &c. The quantity of gas injected was estimated at 6,000 cubic feet per minute, and the operation was continued for five or six hours after the gas commenced to come out of the upeast. The fire was then drawn and fresh air forced through the mine by the same pits. After two hours and twenty minutes the cloudy appearance at the upcast disappeared, and a lamp would burn in the gas coming out. The fire was found to be extinguished, though it had been burning for nearly two weeks before commencing this operation. The expense of the apparatus was estimated not to exceed five to ten poulds. In a fire which occurred about two months later (June, 1849) in the same pit, Mr. Darlington,applied carbonic acid nalde in the wet way —with limestone and sulphuric acid. The fire in this case was walled off and the generating apparatus placed in the lower gallery, and a quarter-inch steam jet placed in a pipe inserted through the stopping in a higher gallery. Mr. Darlinuton says: "W Ve commenced injecting carbonic acid through the four-inch pipe at 2 a. ml., and at 5 a. m. the men were at work." Of course the fire was a fresh one, or the rocks would not have had timmle to cool in that time. The expense was fromn ~10 to ~15, or more than that for filling the entire mine with after-damup in the previous case, where the gas was made with "charcoal, the waste coal round the pits, and a little limestone." SECTION IV.-BREAKING, CRUSHING, AND GRINDING ORES. CHAPTER XV. BREAKING AND CRUSHING. Ores which reach the surface in large solid blocks require to be broken into fragments that can be easily handled before they can be placed in machines for reducing them to still smaller fragments, or to powder. The sledge is the simplest and most common tool for this purpose; and it is followed by spalling haammers, until none of the fragments are much larger than the fist. Until within a few years this was the common and only way of breaking up ore into sizes suitable to be fed into the mortars of stamp-batteries, and it is still used where only small quantities are to be broken, and the extent of the operations do not justify the expense of obtaining suitable machines for the purpose. HEAVY STAMPS. The first attempts upon the Pacific coast to substitute machine for hand labor in spalling ore were in the direction of stamps of unusual weight, raised by cams to a height of four feet, and allowed to drop upon the mass of rock to be broken. Stamps of this kind, either single or two in a battery, were placed at the superb mills erected near Aurora, at the Real del Monte, and at the Antelope. They weighed 2,000 pounds each. There were no mortars, but a solid bed or anvil was surrounded with massive grates, made of bar iron, through which the fragments could drop. Masses of ore, from one to two feet in diameter, could be rolled in and subjected to a succession of blows. The two heads could break uD about two tons an hour, but with an enormous expenditure of power, as is evident when we consider that for each blow a ton weight of stamp was to be raised four feet, and also that the smaller the mass to be broken the greater was the force of the blow. Thus when a mass of quartz, say six inches in height, lay upon the anvil, the stamp fell upon it from a height of three feet six inches; but when a block two feet high, which needed a much harder blow, was upon the anvil, the stamp fell only two feet. Similar stamps were in use at Washoe and at Virginia, but were soon abandoned because of their manifest defects and cost. BLAKE'S ROCK BREAKER. The machine for breaking up rock now most in use is the invention of Mr. Eli Whitney Blake, of New Haven, Connecticut, and is generally known as Blake's Rock Breaker. It was designed at first to break up trap-rock into fragments for macadamizing roads. Its value for breaking ores into sizes suitable for feeding to stamps orjigs was quickly seen, and in 1861 it was introduced into California. Its first operation in the mines was at the Benton Mills upon the Merced River. The ore 12 3I 178 MECHANICAL APPLIANCES OF MINING. delivered there from the Pine-tree vein is noted for its hardness and massive character, and it required the constant labor of thirty Chinamen to spall enough to keep the stamps supplied. The same and a greater amount of work was better performed by the machine in a few hours, and effected a saving of seventy-five dollars a day, when sufficient rock was furnished to keep the machine running. From that time it has been extensively used, and is recognized as an indispensable adjunct to every well-appointed stamp mill. The general construction of this machine has been rendered familiar by numerous figures and publications in the United States and in Europe. It consists, essentially, of a strong iron frame, supporting upright convergent iron jaws, actuated by a revolving shaft. The stone s or masses of' ore to be broken are dropped between these jaws, and a short reciprocating or vibratory motion being given to one or both of them, the stones are crushed, and drop lower and lower in the converging or wedge-shaped space, until they are sufficiently broken to drop out, at the bottom. The size of the broken fragments may be regulated by increasing or diminishing the size of this opening between the jaws. But the construction and operation of the machine will be made more clear by the inspection of the annexed figure, accompanied by a description in detail of the various parts. This figure is a sectional side view or elevation of the machine, representing the parts in place as they would be presentedl to view by removing one side of the frame. The parts of this figure which are shaded by diagonal lines are sections of those parts of the frame which connect its two sides, and which are supposed to be cut as under in order to remove one side and present the other parts to view. The dotted circle D) is a section of the fly-wheel shaft; and the circle E is a section of the crank. F is a pitman or connecting rod, which connects the crank with the lever G. This lever has its fulcrum. on the IIII H al~i,I / i Blake's Rock Breaker-section. friame at H. A vertical piece, I, stands upon the lever, against the top of which piece the te toggles J J have their bearings, forming an elbow or toggle-joint. K is the fixedjaw against which the stones are crushed, BREAKING AND CRUSHING ORES. 179 This is bedded in zinc against the end of the frame, and held back to its place by cheeks, L, that fit in recesses in the interior of the frame on each side. M is the movable jaw. This is supported by the round bar of iron N, which passes freely through it and forms the pivot upon which it vibrates. O is a spring of India-rubber, which is compressed by the forward movement of the jaw and aids its return. Every revolution of the crank causes the lower end of the movable jaw to advance toward the fixed jaw about one-fourth of an inch and return. Hence, if a stone be dropped in between the convergent faces of the jaws, it will be broken by the next succeeding bite; the resulting fragments will then fall lower down and be broken again, and so on until they are made small enough to pass out at the bottom. The readiness with which the hardest stones yield at once to the influence of this gentle and quiet movement, and break down into small fragments, surprises and astonishes every one who witnesses the operation of the machine. It will be seen that the distance between the jaws at the bottom limits the size of the fragments. This distance, an'd consequently the size of the fragments, may be regulated at pleasure. A variation to the extent of five-eiglths of an inch may be made by turning the screw-nut P, which raises or lowers the wedge Q, and moves the toggle-block 1i forward or back. Further xvariations may be made by substituting for the toggles J J, or either of them, others that, are longer or shorter; extra toggles of different lengths being furnished for this purpose. Machines are made of various sizes. Each size will break any stone, one end of mwhich can be entered into the opening between the jaws at the top. The size of the machine is designated by the size of this opening; thus, if the width of the jaws be 15 inches, and the distance between them at the top 9 inches, the size is called 15 by 9. The product of these machines per hour, in cubic yards of fragments, will vary considlrably with the character of the stone broken. Stone that is brittle, like quartz, granite, and most kinds of sandstone, will pass through more rapidly than that which is more tough. The kind of stone being the same, the product per hour will be in proportion to the width of the jaws, the distance between them at the bottom, and the speed. The proper speed is about 180 revolutions per minute; and to malke good road metal from hard, compact stone, or to prepare ores for stamps, the jaws should be set from 14 to 1~ inches apart at the bottom. For softer and for granular stones they may be set wider. The following table shows the several'sizes of machines commonly made, the product per hour of broken stuff from the hardest materials, when run with a speed of 180; the power required to perform this duty; the whole weight of each size in round numbers, awrnd the weight of the heaviest piece when separated for transportation. Size.Procduct per Powerrequired. Total weig~ht.Weight of frame Size. ourr Powerrequired. Total weight. and parts attached. 10 by 5 4 cubic yards. 6 horse. 6,600 pounds. 3,200 pounds. 10 by 7 4 cubic yarTds. 6 horse. 7,7.00 pounds. 4,100 pounds. 15 by 5 6 cubic yards. 9 horse. 9,100 pounds. 4,700 pounds. 15 by 7 6 cubic yards. 9 horse. 10,200 pounds. 5,600 pounds. 15 by 9 6 cubic yards. 9 horse. 11,600 pounds. 6,800 pounds. 180 MECHANICAL APPLIANCES OF MINING. The whole length of the machines to the back-side of the fly-wheels is from 8 to 8~ feet; height to top of fly-wheels, 5 feet; width, from 4 to 5 feet. The machine may be driven by any power less than that given in the table, yielding a product per hour smaller in the same proportion. Either of the sizes mentioned will break quartz enough in a few hours to feed a forty-stamp mill for one day. A machine of less capacity would of course have a smaller mouth and would not take large stones. It is usual therefore for mill-men to use the largest mouthed machine, and to run it a fen hours each day. The rough quartz in blocks as it comes from the mine being ready on the platform near the mouth of the breaker, two men can feed it into the machine and break it up at the rate of five to ten tolls per hour, according to the size of the machine. Breakers have been made larger than any of the above for breaking very large blocks of ore. They are in use at Lake Superior, where they take in masses of ore eighteen inches in diameter by twenty-four in length, and crush them Without difficulty. The fragments from these large breakers are received by two or three of the machines of the ordinary sizes and are broken again, so that the pieces will all pass through a two-inch ring. The metallic copper is readily picked out by hand from this broken ore. These large machines would be useful at many mines in California and Nevada, andt would pernit sledging to be dispensed with. The machine is made without the lever, and works very slowly, but without loss of power; since, when it is not crushing, the only power consumed is that required to overcome the friction, whereas with the heavy stamps, as we have seen, the greatest expenditure of power is when the least work is performed. There are some modifications of the construction of this machine as here described. In England and France they are comlmonly made without the lever, the eccentric shaft being mounted on the top of the frame directly over the toggles. A pitman connects the eccentric shaft with Blake's Rock Breaker, without the lever. BREAKING AND CRUSHING ORES. 181 these toggles, and thus produces the oscillating motion of the jaw. This construction is shown by a sectional view as before, one-half of the frame being supposed to be removed. One only of the fly-wheels is represented. This is the form of the machine exhibited at the Paris Exhibition by the manufacturers under the patent in France. The mouth of this machine is expanded, hopper-like, so as to be more convenient for the reception of the masses to be broken. This may be a desirable addition in some cases, where comparatively small stuff is to be broken and is to be shoveled in from a floor lower than the mouth of the machine; but when the mouth is placed, as it should be, on a level with the floor of the dump pile, the hopper is not required. The rock breaker may be successfully used instead of stamps to obtain either coarse or fine, fragments suited to concentration. It has been attempted to increase the fineness of the product of the machine by placing an' obturator" or obstruction, such as a triangular barl of iron, under the outlet between the jaws, arranging it so that it can be raised or lowered by means of screws, in order to diminish or increase the size of the outlet for the delivery of the crushed stuff. The effect of this obstruction is to retain the stuff between the jaws until it is so much broken and comminuted that it will sift through the narrow slits left on each side of the bar. This method of operating may be successful with some materials but involves a considerable expenditure of power. It is also attended with some danger to the machine, since with materials that are easily impacted to a hard mass, the entire space between the jaws may become so tightly filled that some part of the machine must give way. The massive frame of a machine in California was broken asunder in this manner, simply by permitting the outlet between the jaws to become closed by the accumulation of a heap of broken stuff below it. O(bturators have been tried; but the discharge from the machines is rendered so slow by them that they have been discarded as not practically valuable. A better way to accomplish the object is to first break the ores in an ordinary machine and then pass the fragments through a machine with a mouth 10 by 2 inches7 the jaws of which move only about one-eighth of an inch and make 600 bites in a minute. Machines of this kind have been successfully used in preparing ores for jigs. At the Churprinz mine, Freiberg, Saxony, two rock breakers are used to prepare the lead ores for the various concentrating machines. One breaker takes the rough ore as it comes from the mine and breaks it up into coarse fragments; these pass to a second breaker with the jaws set nearer together, so as to make fragments small enough forjigging. The finer portions of the first product are separated from the coarse by means of revolving screens. The fragments of ores produced by rock breakers are better adapted in size and shape to the operation of concentration by jigging than the fragments made by rollers and stamps. When set coarse, for breaking quartz to be fed to stamps, the product consists of masses which do not exceed a certain size, and this permits a uniformity in the action of the stamps which cannot be obtained upon quartz broken up by hand, since in the latter case there is great irregularity in the size of the masses, and, as a general rule, the hardest and toughest are the largest. With selffeeding batteries, it is very important that the ore should be uniformly broken, and machine-broken rock is especially well adapted to automatic feeding. When the masses fed into batteries do not exceed a certain size, the wear and tear of grates is less than when the size is irregular. It is easy also with breakers to reduce the whole quantity of the ore to 182 MECHANICAL APPLIANCES OF MINING. be stamped'to fragments very much smaller than can be obtained by hand-breaking, unless by an expenditure of time far beyond what the economy of the breaking will permit. Quartz thus reduced greatly increases the product of a stamp-battery; the stamps have a greater and more effective blow, and mill-men often report that they can work froin twenty to twenty-five per cent. more quartz with a breaker than without it, the battery being the same. The jaws of the breaker are the only parts subjected to rapid wear, and in California and Nevada it is usual to provide the movable jaw with movable faces of hard white iron. These are made about four inches thick, and in such a form that they can be turned over or end for end, until they are too much worn to be longer used. They are secured to the jaw by means of conical bolts, and bedded in zinc or refuse typemetal, in order to have an equal and solid bearing. The forward or fixed jaw can also be reversed in its bed, and is held back to its place by wedge-shaped cheeks on each side. It is usual to make both jaws with vertical coarse corrugations or furrows, so that the ridges of one jaw are opposed to the depressions on the other, thus giving a zig-zag form to the aperture at the bottom. This tends to prevent long and thin pieces from slipping through without being broken: but it is not otherwise essential to the satisfactory operation of the machine, and plain jaws are frequently used. CRUSHING BY ROLLERS. Before the introduction of rock breakers, the most common method of crushing was by strong iron rollers, revolving slowly in close contact or pressed together by powerful weighted levers. The stuff was allowed to drop from a hopper between the rollers, and motion having been given to one by means of steam or walter power the other roller was carried around by friction. This form of crusher is generally known as the Cornish crusher or rolls, and is much used at the metalliferous mines in Cornwall and elsewhere abroad. One was erected at the Keystone copper mine in Calaveras County, California, a few years ago for crushing copper ore preparatory to jigging. The figure annexed will serve to give an idea of the generial form of C 14- > Rollers for crushing. construction of the Cornish crusher. The rolls are supported by very strong bearings, in a frame strengthened by wrought-iron bolts. In the construction here shown, the rollers are kept in contact by India-rubber springs, or buffers, of great elastic force, one on each side of the frame. Each buffer is composed of six rubber disks, one inch thick; separated by a disk of iron one-quarter of an inch thick. The necessary initial pressure is obtained by means of two strongly-made screws in the axes BREAKING AND CRUSHING ORES. 183 of the buffers; and by screwing up or unscrewing the nuts on these screws the pressure may be increased or diminished, according to the necessities of the case. It is evident that it would not answer to rigidly fasten the rolls in contact. The accidental dropping of a steel tool, such as a drill or a hammer-head, between them would break the machine; and, moreover, they would not crush as fast and well without a certain amount of yielding to the materials carried through between them. But the use of rubber springs is a novel way of giving the necessary resistance. It is usually accomplished by means of weighted levers, the short arms of which being bent downward press upon a cylindrical bar or follower, which bears directly upon the back of one of the bearing blocks of the roll; or, what amounts to the same thing, the lever is made, by means of rodls, to draw the bearing of one roll toward the other, thus keeping the surfaces of the rolls in contact. The amount of the pressure is determined by the extent to which the lever is weighted. This is the usual Cornish method; that by springs of rubber has been tried in Germany. The great advantages of springs are, that the machine occupies less space than when fitted with levers, and that the resistance or crushing pressure increases with the degree of separation of the rolls, whereas with the weighted levers the pressure is constant. In practice it is found that the product of rolls geared together is greater than when one is carried around merely by the friction of the stuff crushed. It is also usual to have three or more rolls where the crushing is wholly done by rolling. The upper pair are set so as to take in large masses; and to increase the hold of the surface of the rollers upon the masses they are made fluted. The fragments falling from this first pair of rolls are divided between two pairs set below and pressed closely together. The diameter of crushing rolls varies from 14 inches to 34 inches, (27 inches is a common diameter,) and the length or breadth of face from 12 inches to 22 inches. The rolls at the mine of Devon Great Consols in Cornwall are very large, having 34 inches diameter, and 22 inches face, and a pressing force on the rolls of 458 hundred-weight, revolving seven times per minute, and crushing 65 tons in 10 hours, at a cost of 21 pence per ton. The annexed tabular statement of dimensions of rollers at various mines will give further cletails.*' Extracted from Hunt's edition of Ure's Dictionary. 184 MECHANICAL APPLIANCES OF MINING. Dimensions and p)roduct of Cornish rollers at various mines. ROLLERS. SIFTER. a~~ ~ ~ ~~~~ a i 0 Name of mine.' 0I;,4~~~~~~~~~~~~~F;" II 0 F 9 b~~~~~..a P4 4 P+4 p In. In. Sq.. Cq. n. Sr. Feet.. Pence. Grassington mines..........I27 12 51, 593'91 21 48 61 37 14 --- o —--- 2~~~~~ 48 MIinera ------------- ------—. 14 14 8 4, 920 73~1 24 42 9 48 10 6-10 6 20 f21 C -ystwith, No. 1 ---------- 27 14 4 4, 748 7- 20 33 9 24 16 - 32 2 C~ ystwith, No. 2~ —— ~ —---- 27 14 4a1 5,341 85 24 36 9 24 16 35 2. In. In. Sq. In. Cut. En. In, Sq~n. Feet. one.!Pence. Grassington mines. 27 12 5~ 5, 593'91 21 48 6~I 37 ]14F ee.. 0 Minera -~~~I141 141 81 4, 920] 73~144 81061 0 2 Cwmystwith, No. 1 - 27.14.4.4,]748178 20 3379824716232321 Cwmystwith, No.2 -......27 14 44 5,341 [83 24[36{ 9 [241.. 35 2~ Goginan —..-. —-.- - -..... 30 14 5- 7,254 39 20 39 9 3616.... 30 2Cwm Erfin... —-.... 27 14 71 8,902 293 26 32 9 30 16 20 3 Lisburne, No. 1............ 27 15 6 7, 632 180 22 36 121 30 16... 42 2 4.. 42 2-~2 Lisburne, No. 2 —-----—.. —127 15 6 7,632 224 22 36 12, 30 16 42 2Derwent....................27 14 7 8,309 227 22 (iO 16 15.... 60 24 Goldscope -.................{ 14 18 14 11, 060 6 -.-..-.{-. —...[.-.. —...... 25 2z2 East Darren ---------------- 30 18 6 9, 996 207 24 36 16 45 16 25 24 Cefn Cwm Brwyno....-... 20 13 5 4, 080 84 20 48 16 27 14 -—. 20 2a Lisburne, No. 3..... —...... 18 16 8 6, 432 169 22 36 25 30 16 -- 42 2Jandudno —----- - 18 15 15 12, 705 61 —...-.I.-. —..{.-..-.....- 30...... Wheal Friendship.........-23 12 10 8, 670 123 24 36 36 30 13 13 20 11 Pontgibaud.-.-........ 25 12 124 12, 075 36 22 44 36 60 15 15 17 24Devon Great Consols-.. —.... 34 22 7 16,443 458 241 84 64 [21 —--- - 65 3/ Fabrica la Constante, Spain - 24 15 10 11, 300 147 25 45 100 30 15 15 50 24 Fabrica la Constante, No. 2.- 27 15 10 12, 720 110 25 53 100 30 16 16 50 34 Fabrica la Constante, No. 3.. 24 12 16 14,464 84 25 45 3,600 38 (!) 13-20 19 abrica la Constante, No. 4 -- 27 15 15 19, 080 93 26 58 3, 600 45 (4) -- -- 13-20 19 Goldscope has two sets of rolls, one fluted; the other plain. i Two sifters, one 24 inches, the other 22 inches in diameter. Jacob's ladder, 192 feet. WEAR OF ROLLS. The surface of rollers soon becomes much worn; and when made of chilled iron, the irregularity of the chilling is soon made manifest by the unequal wearing away, the soft parts being hollowed out, while the harder remain in ridges or irregular bulges. It is therefore found preferable to use ordinary hard pig iron, or a mixture of hard white iron, similar to that used for the dies and shoes of stamps. The rolls are also made with an outer casing or shell, a short, hollow cylinder, that can be slipped upon the axis or core of the roll, and removed when too munch worn. This is usually cast so as to make a firm lock-joint upon the core, or it is keyed by means of two or three keys or wedges slipped into recesses extending through from one side to the other at the line of junction, one-half of the hole being in the core and the other half in the shell. The annexed figure shows a method of securing the facing upon rolls by tapering keys.* The outer cylinder C C can be slipped off and on the central conical cylinders without difficulty, and is secured in its place by six tapering or wedge-like keys, K K, placed at equal distances around the axis, and firmly held by the strong nuts at one side. This drawing is one-ninth full size. The roll has 14 inches diameter and 9 inches face. In all crushing machines of this description a large amount of the stuff must necessarily be passed through between the rolls several times; for it is evident that when a hard lump of ore passes thronugh This figure is taken from the Jahi-buch fur den Berg-und-Hiitten-Maun, 1867. Taf. ii. BREAKING AND CRUSHING ORES. 185 and separates the rollers more than is usual, a considerable quantity of stuff drops through without being acted on. The result is the same when the rollers are fed too rapidly; they are kept asunder most of the time, and much K ) coarse and uncrushed material __l/.... passes through. The crushed product is al-. ways received upon gratings or - ---— > — a revolving screen, by which all the fine or sufficiently broken portions are sifted out. The coarse fragments which require to be again crushed are dropped into a raff-wheel, or ~. > elevator, by which they are car- Roller- iber, Saony ried to the upper floor or plat- R form and thrown out, ready to be shoveled into the hopper again. This raff-wheel is usually 15 feet in diameter, and resembles a waterwheel, but is made with the buckets turned inward. This forms a succession of box-like cavities, from which the ore falls out when, by the revolution of the wheel, they are carried to the top and inverted. Rollers are usually driven by strong gearing, but at the Exposition in 1867 a set of rolls exhibited by Messrs. Huet & Geyler were driven by a belt, as is also a machine at Freiberg, in Saxony. M. Huet mentions rolls with as great a diameter as imn. 20; but the rollers in machines of their construction, driven by a belt upon a shaft carrying at the opposite end a small pinion, working into a large spur-wheel upon the end of the shaft of one of the rollers, did not exceed 0m. 09 in diameter. The hoppers of rollers for crushing large quantities of stuff are usually made large enough to hold a ton. LUNDGREN'S PULVERIZING BARRELS. An apparatus for fine crushing by means of rolling in a cylinder with a great number of small balls of hardened iron, was erected and used for a time at the Benton Mills, upon the Merced River, but was finally abandoned. The cylinder or barrel used was made of boiler iron, lined on the inside with shoes of hard iron, one inch thick. Its length was three feet and diameter five feet. The material, consisting of the battery sands, was screened and introduced in charges of 650 pounds. Some 2,000 pounds of chilled iron bullets, half an inch in diameter, were then added, and the whole made to revolve on its axis slowly, about 26 revolutions in a minute, for one and a quarter hours, at the end of which time the sand was reduced to a fine powder. The wear upon the balls is said to be very slight. CRUSHING BY PERCUSSION- CENTRIFUGAL CRUSHERS. For crushing minerals and other hard substances by projection from a revolving wheel or disk, an apparatus was devised and operated for a time by Messrs. Whelpley & Storer, in Boston, Massachusetts. To the part for coarse crushing they gave the name of whirling table. This is a saucer-shaped mass of metal, three and a half feet in diameter, weighing 800 or 1,200 pounds, annd revolved horizontally with great velocity, as great as 1,Q25 times per minute. This table or disk forms the bot 186 MECHANICAL APPLIANCES OF MINING. tom of a circular cast-iron stationary tub, eighteeil inches deep, the sides of which are perforated so as to allow small fragments to pass out. The table is so supported upon a vertical shaft, with a steel pivot resting in a cup of oil, that it revolves with but little friction, and the high velocity of rotation is maintained with but little expenditure of power. When any hard substance, such as a mass of quartz, is thrown into the cavity during the rapid rotation of the table, it is at once forcibly thrown outward against the grates, and, falling backward in fragments, these are in turn thrown rapidly outward again by the centrifugal force, and the operation is repeated until the fiagments are small enough to pass through the perforations and escape to an outer chamber. If these perforations are half an inch in diameter, the fragments of the quartz will be like small gravel mixed with sand. It is claimed that one of these tables will reduce more than 200 tons of ordinary quartz in pieces from three or four inches in diameter to the size of coarse gravel in twentyfour hours. The inventors allow, in practice, an average of ten-horse power for the full working of one of these tables, and they rate the expenditure of power at about one and a half-horse power per hour for each ton of quartz. To obtain this result the velocity of the table must exceed 1,000 revolutions per minute. Blocks of hard white iron, such as Franklinite, are bolted upon the outer edge and face of the table. These, at high velocities of rotation, first strike the mass to be broken and splinter it before it reaches and wears the surface. With low velocities the machine is rapidly worn and injured, by the dragging of the stone over its surface. With the higher velocities only the edges of the hammers or iron blocks are worn, and these blocks last a much longer time in proportion to the amount of work done. The balance of this revolving table is regulated by bolting pieces of iron to its under side. This machine is not intended to be used as a pulverizer, but rather as a breaker, taking stuff three to six inches in diameter and reducing it to the condition of mixed sand and gravel, with a small percentage of dust. For carrying the reduction still further and gaining a product as fine as dust, another form of centrifugal apparatus, called the pulverizer, is used. The pulverizer, as described by the same inventors, consists of four parts or elements: 1. An autolmatic feeding-mill, which furnishes a regular and constant supply of the material to be pulverized. 2. An iron drum or cylinder, containing an air-wheel, which converts the sand or gravel into dust, chiefly by the action of the particles upon themselves in the rotary currents of air created by the wheel. The material can be retained in the cylinder until it is completely reduced. 3. A. fan-blower, by which the dust is drawn from the pulverizing drum as fast as it is generated. 4. The dust so drawn off is received and collected in a chamber or series of chambers. The pulverizing cylinders, in. use for two years or more, chiefly in crushing bones, were forty-two inches in diameter and eighteen inches in breadth. They had twenty-four paddles or arms of hard white iron, six inches long by three and a half in breadth. The revolution was in a vertical plane. It was found by experience that the proper velocity for economical results was about 1,025 turns in a minute. " This will require fifteen horse-power to produce 1,500 pounds of quartz powder, four-fifths of which should pass through a sieve of one hundred threads to the linear inch." The inventors further state that a very fair estimate of production allows one hundred pounds per hour of average dust to the horse power. Efforts have been made in California to perfect a form of rotary STAMPS AND STAMP MILLS. 1 7 crusher for dry crushing, and the mining public is indebted chiefly to Mr. AMoore, of the Vulcan Foundry, for persistent efforts to solve the problem of a cheap and durable machine for dry crushing upon this principle. Much money was expended, and for a time it seemed as if success had been attained, but the practical difficulties inherent in this method proved insurmountable and the efforts to perfect the apparatus ceased. One of the chief difficulties was found to be the excessive vibration of the revolving disk at the required high velocity, the result of unequfal wearing. The details of the experiments made at the Vulcan would form a very interesting and valuable contribution to mechanical engineering, and it is regretted that expected details on the subject have not been received in time for insertion here. CHAPTEIR XVI. STAMPS AND STAMP MILLS. The stamp is the oldest, simplest, and most effective machine for crushing ores to powder. The breaker and Cornish rolls, already described, act by direct slow presure; while stamps in falling acquire momentum, and strike sharp, quick blows upon the mass to be broken. The iron stamp batteries, now in use upon the Pacific coast, are made chiefly at San Francisco, and have been carried to a high degree of perfection by the joint efforts and experience of the mill-men and the metallurgical and mechanical engineers. It is but just to state that the stamp batteries made there are superior for gold and silver working to those in any other part of the world, and that they have become the type to be followed in the construction of batteries in Chicago, New York, and elsewhere. It is now very rare in California to find the old-fashioned timber, square-stemn stamp lifted by a wooden or iron cam set into a large shaft. Some that were erected in Grass Valley several years ago are still in existence; but the round stamps with cylindrical iron stems, free to rotate in the supports or guides. are now used almost exclusively in California and Nevada. The whole stamp is composed of the following parts: the stem, the tappet, the stamp-head or socket, and the shoe. The mass of hardened iron on which it falls is called the die, and this is placed in the castiron box called the mortar. The stem is usually made of 3-inch or 3~-inch round iron, from 10 to 12 feet in length, and turned off in a lathe and finished so as to be truly cylindrical, and equal in diameter in every part except for a few inches at the lower end, which is made tapering, so as to fit into a conical hole in the top of the head. The tappet, or lifter, as it is sometimes called, is secured upon the upper part of the stem, and forms a projection three or four inches wide, under which the cam catches and lifts the stamp. The first of the annexed figures is a vertical section of the tappet as it appears fixed upon the stein A; and the second an end view or plan, the contrivance for securing it to the stein being shown in both. The tappet is made of cast iron, and weighs from 60 to 70 pounds. It is alike at both ends, so that when one becomes worn it can be reversed upon the stem. Formerly the tappets Were attached to the stems by 188 MECHANICAL APPLIANCES OF MINING. means of screw threads cut upon the latter, the tappet being screwed down as a nut upon a bolt; afterward key seats were cut to receive a transverse key; but these methods have been superseded by the much more simple and convenient device invented by Zenas Wheeler, of CalA ifornia, which has given his name to the tappet. The tappet is cast with a rectangular recess in one side of the hole, for the stem. Into this recess a "gib," B, is placed. This is a rectangular block of wrought iron, flat on one side but hollowed on the other, so as to fit the curvature of the stem. Two transverse slots or openings at the back of the recess are K K, by which the " gib " is wedged powerfully against the stem, so that the tappet is firmly secured at any desired place upon the stem. Thus no key seat or change of the form of the Stamp Tappet-section. stem is required, and the Stamp Tappet-phlLn. tappet can at any time be removed without difficulty muerely by driving out the keys. The stamp-head or socket, as shown in the annexed figure, is cylindrical, and made of the tounghest cast iron, strengthened with wrought iron hoops or bands, CC, CC, at the top and bottom, shrunk on while hot. It is cast with two conical openings, or sockets, one in each end, the upper being for the reception of the A tapered end of the stem A, and the lower and larger opening, B, for the shank of the shoe. D D represent transverse rectangular openings, or key-ways, by means 91 i of which steel wedges can be inserted, so as to bear either against the end of the stamp-stem or against the end of the shank of the shoe, for the purpose of - driving either out. This is often necessary for the 0 shoe, when by wearing it has become too thin, and has to be replaced with another. The stamphead is made in this form for the B purpose of facilitating the removal of the shoe. With proper care the socket lasts for years, and after being once attachedt to the stem Stamp-head. need not be removed; but the shoe S wears out in a few weeks. The form of the shoe is shown by S in the annexed figure, and the die by D. Both are round, in horizontal section, and are cast of the hardest and toughest white iron. The shoes are usually eight inches in diameter across the face, and six inches in length 1 or height from the face to the shank. The die corresponds in diameter at the face, but they are often made with a broader face, sometimes square, andl fitted into recesses in the bed of the mortar. They Shoe and Die. STAMPS AND STAMP MILLS. 189 are made of the same iron as the shoes, and are renewed as fast as worn out. It is usual for the manufacturers to ship these different parts of the stamp disconnected, since their construction permits of their being united with ease, when they are to be placed in the battery. In order to fasten on the tappet, we have seen that it is only necessary to slip it on the stem and then wedge it fast by means of the keys and the gib. To attach the stamp-head it is only necessary to place the socket upon the die in the mortar, and let the tapered end of the stem drop vertically into it. A few blows with a hammer upon the upper end of the stemn will wedge it firmrly into the head, and it is made tighter by allowing it to drop, headand all, upon the die. This is regarded as a permanent connection; but with the shoe the case is different, and, to render it less lifficult to remove this part when worn out, the shank, before being inserted into the socket, is covered with strips of pine, about one-quarter of an inch thick. These are held in place by a string, while the shoe is placed in its proper place upon the die, and the stalup-head is allowed to fall upon it. It becomes tightly wedged in the conical socket, and may be raised with the stamp. After dropping a few times upon the die, (protected by a bit of plank,) it is driven " home; but there must be a little space left between the top of the shoe and the lower surface of the stamp-head. A stamp thus put together, with a three-inch stem and a 200-pound head, will weigh about 620 pounds, the tappet weighing 70 pounds and the shoe 95 pounds. The smooth, round stem of the stamp permits it to revolve in rising or falling, so that all sides of the shoe are turned in succession toward the side where the oquartz or ore is fed in, this being the side where the stamlps with square stems are most rapidly worn away, because on this side the coarse material to be crushed is most abundant. By turning the stamp constantly in the battery this wear is equalized. Shoes should not be allowed to remain in the head until they are entirely worn out, as the wear will be partially upon the wrought iron band of the head, and thus weaken it. When no more than one inch, or threequarters of an inch in thickness is left, the old shoe should be wedged out and a new one put in. It is very important that shoes and dies should be equally hard throughout, so that they may wear away equally in all their exposed parts. To manufacture shoes and dies of good quality for stamp batteries requires considerable judgment and experience. The proper selection and mixture of the iron is of first importance. Ordinary iron'when chilled in iron molds is hard upon the outside, or to a slight depth, while within this hardened crust it is soft, and soon wears away, so that a shoe made in this manner becomes hollowed out like a saucer, as soon as the hard crust or chill of the face is cut through. A shoe made of hard white iron, weighing 95 pounds, will last for six weeks, sometimes longer; but ordinary iron will wear out in a month. A. die four inches thick, and weighing 60 pounds, will last five or six weeks. A worn-out shoe and die will not together weigh more than 30 to 38 pounds. This, however, depends upon the judgment of the mill superintendent. Some mill-men use the shoes and dies much longer than others. The above is the experience at the Princeton mill of 24 stamps, on the Mariposas estate. These stamps weighed about 500 pounds, and crushed about 45 tons of hard quartz in each twenty-four hours. The actual wear of shoes and dies was found to be about 1.54 pounds of the iron per ton of ore 190 MECHANICAL APPLIANCES OF MINING. crushed. The wear of the shoe alone is generally estimated to be from one-half to one pound per ton of hard quartz crushed. BATTERY MORTARS. In the old-fashioned batteries, the mortar or coffer in which the stamps act is made of plank, bolted to a timber frame and lined with sheet-iron, and fitted with a cast-iron bed or shallow trough at the bottom, which serves as the die or anvil. But in working gold ores it becomes of the first importance to prevent all leakage in the batteries, especially -where quicksilver is used. With wooden mortars this is next to impossible, particularly if they ever remain idle for a few days or weeks, and are allowed to dry. It moreover requires considerable time and skill to construct a mortar of wood in. the most approved form, and in a region where time is so valuable as it is in all newly discovered gold and silver regions, it is a great advantage to have mortars already made, which only require to be set upon a suitable foundation to be complete. Castiron mortars fulfill all the required conditions, and they are now and have been for many years in general use in the mines of the West. They are made in mtnany forms, ai(nd of various thickness and weight, by clifferent establishments, but the followving notices of the principal forms made by HI. J. Booth & Co., at the Union Iron Works, San Franciso,*will suffice to show the general style of construction of all. They weigh from 2,000 to 4,000 pounds, and are cast in onle piece, with the exception of the section mortar, intended for transportation in pieces in mouintainous regions. Nihjltmrortar.-The mortar in common use upon the Pacific coast is known as the high mortar, and is here represented in cross-section and in front view. fi i; n iit Higllh Motar. It is four feet long, four feet high, anrd weighs about 3,00)0 pounlds They can be made for three, four, five, or six stamps; but five stamps to each mortar are found to work best. The ore to be stamped is feb through the longitudinal opening B at the back of the mortar, and falls upon the dies (not shown) ranlged side by side ini the bottom. All the rock is supposed to have been made small enough by the breaker to pass through the narrow opening at the top. The large aI am indebtedl to this firm for original workin-g drawings friom which the figuores of batteries and stamps have been reducecl. STAMPS AND STAMP MILLS. 191 opening in the front of the mortar is intended for the screen, made of iRussiani sheet iron, punched with fine holes. This is screwed or tacked securely to a wooden frame, which is slid into grooves C in the section, cast in each end of the frame, and is firmly secured there by long wedges of iron. Two lugs or ears of cast iron, placed at equal distances at the bottom of the opening in the front of the mortar, serve to sustain the screen-frame in front. The whole mortar is securely bolted down to the foundation through the heavy flanges cast upon the bottom. Section mzortars. —Mortars which have to be transported into places difficult of access are nade in sections so that they can be taken apart and packed upon the backs of males. These are called section mortars, and their construction is shown in the accompanying figures. This mortar, like the preceding, is for five stamps, and is four feet long The upper portions A A are made of boileriron. Thle feed opening is shown at B. There are double screens ID ID, one on each side. The method of securing these screes to the openings by means of movable Ings or clamps, is,also shown. The bottom is cast ifv sections c c c, alnd these are accurately fitted togetllher with tollgued and grooved joints, planed, and held by heavy iron bolts running through thlelm from end to enld, and secured by strong nluts upon the outside. Dosnnell's maortar.-A formll of Inortar known as IDonnell's is shown by Donnell's Mortar. 192 MECHANICAL APPLIANCES OF MINING. the figures. The ore, as in the other mortars, is thrown in at the feed opening B, in the section, and the delivery is through one of the two openings in front and in the back. The screen C is narrow and is placed high above the dies, and occupies only a part of the opening in front. The lower portion of this opening and the opening in the back is closed by a door of wood A A, covered on the inside by a sheet of amalgamated copper which catches and retains the particles of gold. By removing the screen C, and making the door A higher, it may be used as a float mortar. Dry mortars.-Wet stamping or crushing is general in California. Mortars for dry crushing are exceptional in that State; but the silver mills of Nevada, crushing ore which has to be subsequently roasted, require this form. Screens for the latter are placed higher and are made wider, and wire-cloth is substituted for perforated iron plates. BATTERY SCREENS. Screens for working ores wet are generally made of Russia sheet iron, of the softest and toughest quality, punched with fine round holes by means of a machine. The size of these holes varies from. number nine of the common senwing needles to number one, the punches used being made of needles. Number one is thus the coarsest, screen. The diameter of the holes of a No. 4 screen is one-twenty-fourth of an inch, and there ane 144 holes in a square inch. In a No. 6 screen, the holes are one-fortieth of an inch in diameter, and there are 324 in a square inch. The screens vary in length from three to three and a half feet according to the length of the mortar, and are from ten to fifteen inches wide. When wooden frames are used, the punched screens are tacked on at the edges with common carpet tacks, a strip of baize or blanket being placed under the edge, to make a tighter joint and to facilitate the removal of the screen when worn out. The screens are also secured in iron frames, made with cross-bars so as to sustain them. Sometimes the holes in the sheet iron are made in the form of narrow slits, about one-third of an inch long, with a view of increasing the rapidity of the discharge of the stamped stuff. For the same purpose, the screens are not placed vertically in the mortars but are inclined foward at the top, as indicated in the figures of mortars, by the recess for the reception of the screen frames. CAMS AND CAMI-SHAFTS. The stamps of California batteries are lifted by iron cams, keyed upon iron shafts, and revolving at the side of the stamp stem under the tappet. Wooden shafts with iron cams inserted are now seldom used upon the Pacific slope, though formerly common, and used also in the gold region of the Carolinas and Georgia. The iron cams are made single, with one arm, and also double, with two; but the single cam is now generally preferredl, as it permits the shaft to be brought very near to the stem and thus brings the commencement of the lifting surface of the cam nearly under the tappet. Cast iron is used; the bearing surface, about three inches wide, is made smooth by grinding; and the hubs are strengthened with wrought-iron bands. The proper form of the curvature of the cam is a modified involute of a circle, the radius of which is equal to the horizontal distance between the axis of the camn-shaft and the centre of the stamp-stem. The curvature should be increased or made greater STAMPS AND STAMP MILLS. 193 than the regular involute, at each end of the cam. This is done so as to ease the contact, by allowing the cam to commence to act upon the tappet at the least practicable distance from the axis of the cam-shaft, where the concussion is least, and to prevent the outer end from scraping or tearing alone' the face of the tappet. This end is also cut out on one or both sides so as to prevent the corner from cutting the circular edge of the tappet. The face of the tappet should always be at right angles with the radius of the curvature of the cam at every part of its course. In practice it is usual to construct the cam-curve by means of a string and pencil. This string must be as long as the required lift or rise of the stamp, added to the distance between the axis of the cam-shaft and the axis of the stem. A circular disk of wood, with a radius equal to the last-mentioned distance, is provided, and, the string being fastened at the edge, is wound upon its periphery. It is placed upon a fiat surface or sheet of paper; a pencil is fastened at the free end of the string, and the latter is unwound, being kept taut, while the point of the pencil traces a line upon the paper until the string becomes tangent to the circle at the point of attachment. This gives the involute with sufficient accuracy, and it is modified in practice as already mentioned. The caum-shaft is made of round iron, usually 4~ inches in diameter, turned and finished off, and having one and sometimes two key-seats cut in it longitudinally between the bearimrgs for the purpose of fastening the cams in their places. One shaft is sometimes made to run fifteen or more stamps; but an independent camu-shaft for each 5-stamp battery is preferable. If there is a line of several batteries a counter-shaft is used. The stamps are held and guided in position in the mortar by guides above and below the tappet,. These guides are, by preference, made of hard wood rather than metal. They are made in halves so that by dressing off the two opposing edges they may be readily refitted to the stem when they are too much worn away. Oak is pteferred; but in its absence pine is substituted. The friction of metal guides is injurious to the stems. The guides for a battery of iron stemstamps made in France in 1867, by Messrs. Huet & Geyler for the mines off Serena, Spain, were made of brass, like ordinary journal boxes, and the cams worked through a slot in the centre of the stein. THE STAMP BATTERIES OF CALIFORNIA. Having now described the various parts of a battery in somle detail,it may be well to direct attention to their combination so as to form a complete stamp-battery such as is now in use in the best.mills upon the Pacific slope. The annexed figure will serve to indicate the general appearance and arrangement of one of these batteries and the frame for its support. This is a sectional elevation of a self-feeding stamp battery, as constructed for working gold quartz. The frame is of pine timber securely braced and held by tie-rods. One end of the iron mortar is supposedc to be removed so as to show the interior. The hopper-shaped box, C, is the self-feeding arrangement. It is shaken at each blow of the stamp by means of an upper tappet which strikes upon one arm of a lever, by which motion is colmmunicated to the forward end of thIe feed-box, C. It will be observed that the cam-shaft is driven by a belt running fromn a counter pulley below. The double cam is shown, and the movable arm or bar used to hold or " hang up" the stamp when the battery is not in action. The scale of this drawing is about one-quarter of an inch to one foot. 13 M 194 MECHANICAL APPLIANCES OF MINING. Battery for workikmg gold qlartz. The next figure shows the construction of a battery and its frame for a wet-crushing silver mill. The ore, after passing through a Blake's rock-breaker, is received in the feeding box mounted upon rollers. From this it drops into the mortar. This mortar is made with grates upon each side. The stamped ore, after settling in vats, is worked by charges in pans. The framework of this battery is different firom the preceding, but the arrangements for feeding, hanging up stamps, &c., are similar. STAMPS AND STAMP MILLS. 195 Wet-crushing Silver Battery. HOWLAND'S ROTARY BATTERY. This is a, colmpact and portable form of battery, designed and patented by W. H. Howland. It was introduced to the notice of the mill-men of California and Nevada several years ago, and was at first used to a considerable extent, but was gradually replaced in nearly all the mills by the ordinary straight battery. These batteries were early adopted by Mr. A. B. Paul, in the mills erected by him below Gold Hill, and he has recently given his opinion of their merits as follows: "No act of mine in mining has been more criticised than the adopting of these batteries in my VWashoe operations. Their adoption was no blind work, as I had used them for three successive years previous, and in no test with other mills was I beat in returns. I had then, and have now, great faith in 196 MECHANICAL APPLIANCES OF MINING. their principle. It certainly is in the right direction. They will, in time, I am confident, become popular, especially when introduced with the later improvements, on accounlt of their simplicity, efficient working, and cheapness." 111T11 A X 1' - ~~Howland's Rotary Battery. ii /J~~~~~~' i::' i,, lt t' I ii lJU i i I ~ ~ owndsRtrBtey STAMPS AND STAMP MILLS. 197 It is claimed by the inventor that very great improvements in the construction have recently been made, based upon the experience of seven years of constant working of the old style of the rotary iron battery. It is now offered by the Miners' Foundry to miners as a "new and highly improved rotary qary quartz mill," of less cost than the straight batteries, and requiring less power. The construction is shown by the figure, page 196.'The whole battery is of iron; the stamps are set in a circle around a central vertical shaft carrying the cams. Motion is imparted to this shaft by means of bevel-gearing. The cams are thus carried round horizontally, and lift each stamp in succession. These rotary batteries are cast in three sectious. The first section has the mortar or base, screen frames and feed openings in one piece; the second section contains the lower guide boxes, (which are of wood,) driving gears, and cam-wheel; the upper section contains the upper guide-boxes. These three sections are bolted together, with thin pieces of wood-packing between each. The stems, tappets, stamps, shoes, and dies are the same as in the ordinary cast straight batteries. The openings for delivery through screens of the ordinary construction are seen at the base. The stamped stuff collects in the annular trough, cast ill one piece with the mortar, so that there is no leakage, and is discharged by a chute at one side. It is claimed as one of the advantages of this improved form that there is more metal in the mortar or base than in the old form of rotary battery, and that the leakage at the base of the column, the jar and loosening of bolts, and the wear of guide-boxes, formerly complained of, are now entirely obviated. Its compactness and lightness as compared with the ordinary straight battery, and its being complete in itself, not requiring timber framing and supports, commend it specially to those who wish to work their ores in districts remote froml supplies of timber. Mr. WV. D. Gray, the superintendent of the mill of the Imperial Company, at Gold Hill, Nevada, writes to Mr. Howland, February, 1869, as follows respecting the rotary battery: Yours of 10th insta~nt is at hand, in which you speak of having just finished and shipped for White Pine an 8-stamp rotary battery, made from a new and improved set of patterns. For a new country, where lumber is scarce and labor necessarily high, there is no battery now in use that will equal yours. The little time required to set it up ready to run is an important consideration. The greatest objection urged against the rotary battery has been the cost of keeping them in repair, compared with the straight battery. But my experience for the last eight years proves this a mistake. The annial report of the Imperial Silver Mining Company shows quite a percentage in favor of the Gold Hill mill (five 8-stamp rotary batteries) over the Rock Point mill, both in cost of repairs, expense of running, and yield per ton of ore worked-the first of which I have had charge of for the last five years. The Rock Point mill, run by water, has straight batteries. I think this comparison can be fully substantiated, as far as expense of repairs is concerned; also as compared with any other mlill run in Storey County for the last five years. The mill above referred to was designed for the Grant District, and weighed, when complete, less thanl six tons. The stamps weighed 600 pounds each, and were designed to make 100 drops per minute. When working -up to its full capacity it will crush from twelve to sixteen tons, dry, in twenty-four hours. The total height of the machine is about eight feet, and the weight of the mortar is 3,000 pounds. WILSON'S STEAM STAMPS. One of the most successful of the attempts to apply steam direct to the stems of stamps has been made by Mr. T. R. Wilson, of Philadel 198 MECHANICAL APPLIANCES OF MINING. phia, Pennsylvania, whose mills have been in practical operation at several of our western mines. The general appearance and arrangement of the battery is shown by the figure. Steam is taken directly by a twoinch pipe to a short cylinder around the stem of each stamp above the frame and by suitable valves is made to act under or above a piston. upon the prolongation of the stem, so as to either raise or throw down the stanp at will. The force of the steam can thus be added to the weight and momentum of the stamp inl falling, in order to increase the rapidity and force of the blows, and thus to give an increased product of stamped ore in a given time. Two stamps are placed in each battery. The mortar is made in the usual form for double grates, one on each side, but is heavier than those intended for ordinary stampns. The two stamnps are intended to Totl aastrike about 400 blows per minute, l it is claimed by the manufacturers that they will stamp fine one ton __ lor more of hard rock in one hour. T hIt is automatic in its action, cams being adjusted upon the upper ends of th e stems as, nd operating the ness-_ o valves as the stems move up and........s and _____ _ Ldown. The following data will show the force with which the Wilson's Steam Stamps. stamps may be made to strike: Inches Diameter of cylinder, 5- inches, area in square inches.-....... 24. 8 Diameter of upper piston rod 2 inches, area in square inches.... 1 Total area of piston for down pressure of steam -............... 21. 7 Pounds. Multiply by pressure of steam in the boiler, (70 pounds)........ 1, 519 Add weight of stamp and stem.............................. 492 Whole force of blow........................................ 2, 011 This shows a force of about one ton, and it is so considered by the inventor. The steam-pressure at the battery is usually less than stated, say 65 pounds. The length of the cylinders is 7~ inches, and the thickness of the piston is 3 inches; there is therefore room for an extreme stroke of 144 inches, but an allowance must be made for the wear of shoes and dies. Inii setting up the machine an allowance of five inches is made for this, a space being left of this length under the piston, when the shoes and dies are new. This leaves a space of 91 inches for the movement of the piston; but in practice it is not run over 6 inches, STAMPS AND STAMP MILLS. 199 this stroke or fall of the stamp being found to be quite sufficient. To vary the length of the stroke, the position of the cam is varied upon the top of the stem, being screwed clown for long strokes and upward for short strokes. The screw thread is not cut so low as to make it possible for the piston to strike the cylinder-head. The dies are made in the usual way, and are recessed to a depth of an inch in the bottom of the mortar, which must be bedded upon a firm foundation. ADAPTATION OF STAMP BATTERIES TO QUARTZ CRUSHING. The action of stamps is peculiarly favorable to the extraction of free gold. The metal, except in rare cases, is best liberated by simply breaking up the quartz without any grinding or rubbing. Trituration rapidly cuts up and disseminates the gold in such an extreme state of division that it passes off in the water and cannot be recovered. These observations apply in general to all ores. The product from stamps is more granular and contains less fine powder and dust than that of a grinding mill. This is due not only to the manner in which the stuff is acted upon, but also to the manner in which it is delivered. The constant swash of the material and the dash of the stamps carry the finer portion away, and only those portions remain which are too coarse to pass through the screens. Another advantage in respect to gold or any other malleaible metal is that a direct blow merely flattens the particles without wearing them away, while trituration cuts and wears them away. Gold, also, when in coarse grains, by its great specific gravity settles in the lower part of the mortar under the sand around and between the dies. The swash of the sand serves to keep the amalgamated copper plates clean and bright, and thus in the best condition to seize and hold the freshly liberated gold particles thrown into contact with them. Another reason of the great practical efficiency of stamps over other forms of apparatus for fine crushing is the fact that a wide ranige in the size of material fed is admissible. They act lupon either fine or coarse material. Grinding machines require rock to be first broken up so that their surfaces may act upon as many fragments as possible at the same time; but with stamps, the rock fed may vary from imere sand to pieces three or four inches in diameter. All are crusheld together, without clogging or causing an increased strain upon the driving-gear, however rapidly or irregularly they are fed. The constant flow of water through the mortar carries out the fine material and leaves the coarse to be further acted upon. DETAILS OF SEVERAL STAMP MILLS. In further illustration of the construction and working of stamp mills, the following details regarding some of the principal mills of California may have some value. They are drawn -from the manuscript notes of the writer, made at different times during visits to the mines and mills. The 40-stamp mill at the Hayward Mine, Sutter Creek, Amnador County, had in June, 1866: Stamps in batteries of five stamps each. Battery boxes of wood. Low trough mortars of cast iron. Weight of stamps, 450 pounds each; eleven inches lift; 80 blows per minute. Dies seven inches across face; both dies and shoes are used until they are completely worn out, (from four 200 MECHANICAL APPLIANCES OF MINING. to six weeks.) Height of discharge-opening eleven inches above dies; different heights from nine to fourteen inches have been tried, but the height of eleven inches has been found to give the best results. Screens on one side of the battery only and made of the best Russia- iron, No. 11, punched with vertical slits a little over half an inch in length. These screens are narrow, the delivery being through a vertical height of two inches only. As the openings in the screens wear most rapidly upon the lower ends, the screens are reversed after each run. The ainalgamation is effected in battery, the gold collecting chiefly upon an amalga.mated copper-plate at the delivery, directly back of the screens. This plate is four inches wide and is slightly inclined inward. The amalgamated particles of gold accuinulate upon this plate in a thick even coat which call be removed in heavy cakes by the aid of chisels. This plate must be placed at the proper angle with due regard to the velocity of the movement of the stamps and the quantity of water used. The pitch must be just sufficient to keep it clear and no more. The apron, outside, is not made of copper, as is usua-l, since the progress of the amalgamation can be judged of better without it. It is found that the quartz crushes faster when there is not an oversupply of water. Eighty drops of the stamps per minute are necessary to keep the materials properly in motion. When the amalgam is collected, the stamps are hung up," the screens are removedl, and the whole of the interior of the battery an:d mortar is accessible. The amalgam found upon the copper plate is chiseled off, and the fragments are collected in iron vessels. It is then broken up and softened by the addition of a little quicksilver. By this means any fragments of iron and admixed grains of pyrites are floated out to the surface and are washed away. It is then strained through a piece of coarse unbleached cotton cloth, sufficienlt of the liquid aimalgam being taken to give a ball of hard, dry'amalgam weighing about fifteen pounds. At the clean-up witnessed by the writer, about 185 pounds of dry amalgam were obtained in 15 Spund balls.* It was then retorted in an ordinary pot retort with a long beak or tube of wrought-iron pipe. The retort being luted and closed is placed in a rude furnace in the open air, and a wood fire built on the top andl increased gradually. It is estimated that the amalgam will yield about one-third of its weight of bullion, or about $95 in value, to each pound of amalgam. At the Eureka Mill, Grass Valley, in 1866, there were 20 stamps, 815 I)ounds each, 10 inches fall; screens raised three inches above dieface, and five inches in front. Worked well; did not cut. No amnalgamation in battery; the sands collected on blankets and copper plates amalgamated below the blankets. Twenty tons crushed in eleven hours. Allison Ranch in 1865 worked 12 stamps of 1,000 pounds each, 10 to 12 inches lift, crushing about 40 tons a day. These stamps were made upon the old-fashioned pattern, with woodlen stems and square heads. No quicksilver was used in the battery; the pulp flowed over blankets, and the sands deposited were worked in Attwood's colncentrator, and the waste passed through the Lawton pan. Fourteen Lawton bowls were used, and were said to save from $1,000 to $1,200 a monthr. Sulphurets were concentrated in a long rocker, a square box-trough, giving from five to seven tons a week of concentrated sulphurets. At the Merrimac Mill, of 10 stamps, the amalgamation was effected in battery. The copper plates are one-eighth of an inch thick and about' The yield in this case was from about 780 tolls of the quartz, or a two-weeks run. STAMPS AND STAMP MILLS. 201 four feet long. Stamps weigh 740 pounds each; 3-inch stems, 16 inches long; 11 inches to 12 inches lift; delivery four inches above the top of dies. At Rocky Bar Mill, 16 stamps, weighing 1,025 pounds, or an average of 1,000 pounds, each. Jefferson Mill, Brown's Valley, 12 stamps, four in each battery; 750 pounds each stamp; not lifted high but run fast, (72 to 75 drops per minute,) the quartz being soft. Blankets andl a long sluice below them. No. 4 screen; four inches from top of die to discharge. Sierra Buttes Mills, near Downieville, two mills, 12 stamps each; four stamps in each battery; round stems and heads; weight 600 pounds in upper mill, 640 pounds in lower. Strike 60 to 67 blows per minute, and from nine to twelve inches fall, depending upon the wear of the dies. Delivery five inches to five and a half inches above die. No copper plates in battery. No. 4 screens, 144 holes to the inch, Russia iron. They clean up once in 60 days, and 66 per cent. of the whole yield is obtained in the battery, including the front plate attached to mortar. Blankets were used for some time below battery, but were replaced by amalgamated copper plates, extending for 40 feet below the battery, and having a slope of one in twelve. [hable showing work clone by mills on the Mariposas estate, California, dr'i, ng six months ending January 1, 1864. Mil~-ls. ol | Tons reduced Mills. c e Per Per month. day. E Benton —. —-—. ——.- 60o 58. 16 11 3, 688 101 1~-1 $5 59 Mount Ophir ------------- 28 24.22 11 798 91 11 11 03 Green Gulclh. - 40 113. 20 11 6, 924 174 1 9 61 Priinceton - - _. - 24 147. 19 11 6, 651 461 18 13 67 Total and average- - - 15 345 11 18,061 20 1 10 35 The data of measurement of tonlls are from estimates by the bookkeepers or the mill superintendents, and may not be accurate within 12 per cent. At the Bigler Mill, Clear Creek district, June, 1866, there were ten stamps; two Hunter's concentrators; one of Hendy's or Prater's concentrators. The order of succession of the fall of stamps was 1, 4, 2, 5, 3. The amalgamation was effected in batters as much as possible. Two amalgamated copper plates were used, one six inches wide between the top of the dies and the screens, the other six or seven inches wide, placed at the back of the mortar under the feeding chute; both plates being inclined inward so as to be washed clean by the swash of the water. At the celebrated Gould and Curry Mill, as first arranged for dry crushing, the stamps were placed in batteries of five each, and a belt 32 inches wide drove two batteries, (or ten stamps.) As appropriate to this part of the report I insert interesting details concerning the Mettacom Mill stamp batteries at Austin, Nevada. These 202 MECHANICAL APPLIANCES OF MINING. particulars were obtained by Mr. Rayondcl, ahid I extract them from his chapter upon metallurgical processes: The weight of the stamps is nearly 900 pounds each. There is not so much difference of opinion now as formerly among good mill-men as to the proper weight for stamps. As the amount of horse-power (and hence of fuel) required to run a battery depends directly upon this weight, it has been necessary to find out by experience whether heavy blows do as much work in proportion as lighter ones, and where the proper medium lies. The question has quite as much to do with the discharge as with the crushing. The blow of the stamp not only pulverizes the rock, but drives it outward through the screens. In dry-stamping this is the only force which effects the discharge. Hence the weight of the stamp should not be so great as to necessitate slow running. Probably 750 to 800 pounds is the best weight for general use; though if all mills were run as skillfully as the Mettacom, even 900 pounds would not be too heavy. The stems are 3~ inches in diameter. The usual size is 2l, anld these stems are, therefore, nearly 20 per cent. stronger and heavier than ordinary; the proportion being as the squares of the diameters. The advantage of putting a larger proportion of the total weight into the stemn is the diminished vibration from the blow on the tappet. The stems should always be fitted as closely as possible to the guides; but light stems spring or bend, and wear the guide in rising. There is no wear of this kind in falling, so long as the stem is true. The stems are set 8$ inches apart, the bosses and shoes work within about two inches of each other, and the distance between the tappets is about three-fourths of an inch. The whole length of each battery-mlortar is therefore about 5 feet 6 inches. The cam-shaft is rigged with single cams. The old fashion of triple cams is now about obsolete; but the usual form is the double cam, which many mill-men still prefer, claiming, that as it gives two drops of the stamp for each revolution, it saves friction in gearing, and enables the battery to be run at high speeds without running the engine as fast. These and other argumlents for the double cain only prove that it suits the machinery which has been calculated for it. As a matter of fact, however, I have never seen double-cam batteries equal the single cams in speed; and I think Mr. Howell is right in claiming the advantage for single calms, that the shoulder canll be brought directly under the tappet, so as to prevent catching. With the ordinary double cam, the shaft must be set further back fiom the stems, and the cams are easily caught and broken. This subject is directly related to the speed of the battery. The Mettacom mill has vindicated triumphantly the wisdoml of its peculiar features by the most extraordinary running on record. For months together the batteries have been kept at from 98 to 100 drops per minute, rising to 102, or even 105, and never falling below 94; yet there has never been a cam broken in the mill. The Manhattan, an excellent mill, with double cams and stamps weighing only 750 pounds, cannot safely run on the same ore at higher speed than 85 to the minute, and Mr. Curtis, the able superintendent, with the performances of the Mettacom before his eyes, naturally declares himself in favor of the single cam, which would enable him to run his batteries up to 110 per minute. The Mettacom stamps fall 10 inches. The original drop was 9- inches; but it was increased to ease the cams and give less jar. The rebound of the stamps amounts sometimes to 1~ inches. Strange to say, the high speed maintained has not caused excessive necessity of repairs. On the contrary, the battery has stood the strain better than any other within my knowledge. Even the shoes and dies, which were not supposed to be unusually good, being bought for ordinary hard iron, lasted for five months of continuois running without being replaced. This fact cannot be adequately explained. Probably that particular set was a lucky cast. Ordinarily, it would have worn out in about six weeks; but I do not doubt that the heavy charges put through the batteries at high speed protected the shoes and dies from pounding on one another, which they are quite likely to do in ordinary mills, especially when the feeder is careless. A mill running at 100 to the minute keeps the feeder busy; and he does not wait for a stamp to thunder out, by pounding on its anvil, that it has finished its last mouthful and wants another. A fact not to be overlooked in this connection is the great solidity of the battery frame and foundations. Nine-tenths of the stamp-mills ordinarily erected would rack themselves to pieces if run as the Mettacom has been, without breaking so much as a bolt. The gain in quantity of ore crushed is more than proportionate to the increase of speed. As I have remarked, this quantity depends, in dry-crushingr especially, on the discharge. I shall speak of that presently, as it regards the arrangement of screens; but I now refer to the frequency of the drops which supply the direct impulse and the air shock, by which the dry "pulp" is driven through the screens. Mr. Howell found by experiment that with 60 drops per minute he could put through in twenty-four hours only about 4~ tons; 90 drops gave a little over 10 tons; and 102 drops more than STAMP MILLS. 203 15~ tons. If we assume that the increase in consumption of fuel would be the same as that in the power generated by the falling stamps per minute, we shall haveNo. of drops Increase ofe per Horse-power, Increase of Yield mi2nute. per stamp. power. yield. 60 1.36 41 -............. 90 2.04 50 per cent. 10 122per cent. 102 2. 22 10 per cen percent. The increase of speed from 60 to 102, or 70 per cent., increased the yield from 41 to 15~, or 244 per cent. To this should be added the gain in wages, interest on capital, &c., secured by rapid running. This comparison does not fairly apply to wet-crushing, though I am satisfied that in that process also high speeds are the best. But the difference is not so startling. Most wet-crushing mills come pretty neati the average of 11 tons crushed in, twenlty-four hours pIer horse-power developed by each stamp. But the above table shows a variatio from 0.33 tons at 60 to 0.70 at 102. The performance of the Manhattan mill is about 0.45 ton crushed in twenty-four hours per horse-power developed by each stamp; and this is a fair, perhaps a high, average for such mills. When the throat ef the battery is open, the pulp will be thrown both ways, and some of it comes back oil the feeding-floor. This indicates a fact too often ignored in the construction of mortars, namely, that since the impulse given by the stamp is radial in all directions, the greater the surface of discharge the higher will be the duty performed. The Mettacom batteries are not perfect in this respect. They have onlly a single front discharge, but this is 18 inches high, instead of 12, as is usual. It is noticed that the fine pulp comes mostly through the upper six inches, and hence, in most batteries, would be thrown back into the mortar until it found exit below. Various forms of mortar with increased discharge have been recommended. The maximum discharge per stamp is attained by Clayton's circular mortar, containing only one staimp. There are also mortars with universal discharge, ill which the screens go all the way round, being curved at the ends. The most common are the double dischargers, having screens in front and behind, and the feed over the rear screen. The objection hitherto made to all arrangements involving curved screens is the difficulty of properly stretching and keying them, while ill dry-crushing, even a rear screen is found to be inconvenient on account of breakage from coarse ore. Mr. Curtis, of the Manhattan, however, prefers a double discharge, while Mr. Howell cares more for enddischargers. The Mettacom end-stamps are hung with three-eighths of an inch more fill than the others, and still do less work. The order in wrhich the stamps fall.varies in different mills, and for wet and dry crushing. The two extremles to be avoided are a simnultaneous drop of all the stamps, which would rack the frame, strain the engine, destroy the continuity of discharge, and probably break the screens; and a drop in regular succession, (1, 2, 3, 4, 5,) which would shove the ore to one end of the mortar, and give the stamps at one end too much, and at the other end too little, to do. Sbme mill-men plrefer to arralnge the succession so that no stamp shall immediately follow its next neighbor. The orders 1, 4, 2, 5, 3; 1, 3,5,2,4; 4, 2, 5,1, 3, would satisfy this condition. Others prefer dropping the two-end stamps first,as 1, 5, 2, 4, 3, or 1, 5, 4, 2, 3. Tihe wave of discharge or splash of the water through the screens in wet-crushing is to be taken into consideration. In dry-crushing, the objects to be secured are an equal distribution of ore under the stamps, giving an equal work per stamp, and a maximlum discharge of pulp through tihe screens. The latter seems to be best secured by letting the middle stanmp drop last. The outer stamps should then have slightly longer cams, to increase their fall. It will be found that the central stamps take and distribute nearly all the feed. Much depends on the skill and fidelity of the feeder, in both kinds of crushing. Hence the automatic self-feeding batteries used in Cornwall have found little favor in this country. They do not "humor" the stamps; and the difference in regularity of running and in duty performed is more than equivalent to the wages of a good feeder. The screens of this mill are No. 40 brass wire, (1,600 meshes to the square inch,) which is preferred for dry-crushing to the " Russia-punched." The latter are frequently preferred by mill-men in -wet-crushing, on account of alleged greater durability, or in the belief that slits are better adapted to discharge liquid pullp than meshes. I take leave to doubt, however, whether these advantages in any case counterbalance the greater proportional discharge-area offered by wire screens. The Mettacom screens are not vertical, but lean outward about 10 degrees. The pulp generally goes through obliquely, and is as fine as the siftings of a horizontal No. 60 sieve. The angle given has been established as the best for dry-crushing. The gain in amount of discharge, wet or dry, from inclined screens, is universally recognized; but inill-men do not so generally bear in mind that the screen so set should be a little coarser than the fineness required for the pulp, if the best results are to be obtained. Mr. Howell's observation 204 MECHANICAL APPLIANCES OF MINING. is that stamps ordinarily crush faster than the batteries discharge. He has often put the pulp back through his battery, an-d found that it took about as long to go through a sfresh rock. Running slow gives the fine dust a chance to fall back under the stamps; running fast keeps it constantly in motion, and much of it gets out. I venture to suggest some considerations based upon the foregoing facts, and calculated, I think, to put mill-men upon the right track in increasing the efficiency of dry batteries. It seems to me that dropping 900-pound stamps is a costly way of making currents of air to promote discharge. The object of the mill-man should be to get the highest practicable speed from his stamps, and then to give them such facilities for discharge as that every drop shall do its full work in crushing. The increase of the discharge-area is the first and most obvious means, and a useful auxiliary will, I think, be found in producing a current of air with a fall, which shall suck or drive the fine dust through the sieve. I have seen exhausting fans applied in this way in several mills. There was one in the Sheba, at Star City, Humboldt County, and there were several in the early Austin mills, which were finally condemned. Mill-men are too ready to reject such appliances as soon as they cause a little trouble, whether through faulty construction or careless management. But this point will be found too important to be dismissed so easily. I do not remember ever in my life seeing a stamp mnill in which the difficulty of discharge did not really delay the work of crushing. The extreme of excessive discharge, which would do no harm, is carefully avoided, and no one can tell to this day how much the stamp now in use could be made to do by simply improving batteries in this respect. The tide of invention is, it appears to me, running the wrong way. We have innumerable devices to increase the force and efficiency of the blow of the stamp, which is already in advance of the rest of the mlachinery, while the inventions for improving the moortars and discharges are few, generally imperfect, and regarded with too little favor by those practical mill-men who are alone competent to take hold of them and perfect them. The screens at this mill last nearly four weeks. When the threads wear thin they begin to shift, and the screens must be removed. They are turned to prolong the wear. The middle of the screen lasts longest. The dies, when new, come up to within about one inch of the lowest portion of the discharge. It is very important to make this interval, called the " height of issue," as small as the screens will bear. The dies used for five months wore away about 11 inches, and the introduction of new ones raised the capacity of the battery nearly two tons per day'. Much trouble was experienced in keeping the dies in their places in the bottom of the mortar. Finally, 150 pounds of melted lead was poured in, filling the mortar-bed about one inch. This is found to work well. I think that for dry-crushing a single die, filling the whole bed, would be better yet. When it wears on one side it can be turned, and so used till it is worn out. This is a German plan, and used successfully in some dry-crushing mills managed by Germans in this country. The foundation of a battery is the most important part of its construction, and it is the feature most neglected in this country. FewA mill-owners like to put so much money " out of sight;" the work of preparing foundations is parsimoniously, ignorantly, or carelessly managed; and the result is that the batteries cannot be run at high speed, and even at low speed they are continually settling, or getting out of line. The great efficiency and stability of the Mettacom mill is due to its carefully-prepared foundation. The mortar-blocks are set on end, upon solid bed-rock. They are nine feet deep. Before placing them the rock was thoroughly smoothed and leveled, and the bottom of each block was planed true. The upper ends of the blocks being (as is the case with all large timbers) sun-cracked, melted sulphulr was poured into the cracks. The mortars are set on the blocks and screwed down tight. If screwed (as is frequently the case) directly to the blocks, they will in a few months get loose, and rock and sand will work between, putting the machinery out of plumb and endangering the mortar. To prevent this, two thicknesses of blanket soaked in tar were put between the mortars and the blocks. Au arrangement was made by which the settling of the mortars could be measured. It is found that after more than a year of steady running they have sunk uniformly less than one-fourth inch —doubtless due to the compression of the blankets. The freedom from jar in the mill, while the batteries were running at tremendous speed, impressed me as decisive proof of the utility of the arrangements described. There is, however, some vibration in the cam-shaft, which should have been five inches' instead of four in diameter. Mr. Howell recommends also heavier bearings. The latter are now eight inches, and should be ten. No Babbitt metal is used in the upper box; it cannot' be kept in, and smooth iron is therefore preferred. The battery, running at 98 to 100 per minute, requires about twenty-two horse-power, which is perhaps a little more than half the power employed in the -mill, and crushes easily seven tons in twelve hours. This being about the usual duty for twenty-four hours, the rest of the imill, especially the reverberatories for roasting, calculated on that basis, cannot come up to the capacity of the battery; and this great defect in the original plans has never yet been remnedied. I have frequently found mills in which the capacity of the roasting or amalgamating apparatus is quite un STAMP MILLS. 205 suited to that of the batteries. In such cases the extra machinery is practically good for nothing, since the capacity of a mill is determined by its least adequate part. Tile Mettacomn batteries must either runl but twelve hours daily, or they inust run for a longer period at full capacity, and then stand still until the surplus of the pulp has been roasted. AUSTRALIAN M-ACHINERY AND STAMPS. Next to California and Nevada, Australia is the country in which the greatest number of stamp mills have been erected, and where experience more nearly equals our own. It is thus important to glance at the extent and character of Australian mechanical appliances, andl, as far as possible, to compare them with similar machines in this country. The mineral statistics of Victoria for 1868 give some very interesting particulars concerning the weight and cost of stalnp-heads and shanks and lifters, the quantities of quartz crushed per diem, the number of holes per square inch in the gratings, the quantity of water used and the quantity of quicksilver used and lost. They have reference only to the principal gold mines in the several districts; but they will not on that account be less useful. In the Ballarat mining district the stamp-headls and shanks or lifters vary in weight from 4 hundred weight to 8 hundred weight 2 quarters, and the cost is froml ~3 17s. 6d. to ~15 10s. The height the stamphead falls ranges from 7 to 10 inches. The number of strokes made by stamp heads per minute is from 50 to 85. The quantity of quartz crushed per head per diem of 24 hours varies from 1 ton to 4 tons. The number of holes per square inch in the gratings used is fromt 40 to 200.(The latter number is made use of by the Victoria company at Clunes; the grating is fixed at the backl of the stamper-box.) The horse-power required to work each stamp is from 1 to 2. The quantity of water used per stamlp-head in crushing varies fiom 950 gallons to 8,640 gallons per diem of 24 hours. The quantity of mercury used in the ripples per stamper is from 5 to 75 pounds. The quantity of mercury lost per stamp-head per week varies from 1 ounce to 8 ounces. In the Beechworth mining district the stamp-heads and shanks or lifters vary in weight fiom 4 hundred weight 1 quarter 17 pounds to 7 hundred weight 3 quarters. and the cost fioIn ~5 3s. 6d. to ~13 per head. The height the stamp-heads fall varies from 5 inches to 14 inches. The number of strokes made by the stamp-heads per minute is froml 40 to 90. The quantity crushed per head per diem of 14 hours ranges from 16 hundred weight to 4 tons. The number of holes per square inch inl the gratings used is from 60 to 140. The horse-power required to work each stamp-head is from 0.75 to 1.50. The quantity of -water used per stamp-head in crushing varies from 720 gallons to 11,520 gallons per diem of 24 hours. The quantity of mercury used in the ripples per stamper is froln 5 to 70 pounds. The quantity of mercury lost per stamp-head per week varies from ~ ounce to 8 ounces. In the Sandhurst mining district the stanmp-heads and shanks or lifters vary in weight from 5 hundred weight to 8 hundred weight, and the cost from ~4 5s. to ~8 11s. The height the stamp-heads fall varies from 6 to 18 inches. The number of strokes made by stamp-heads per minute is from 25 to 75. The quantity of quartz crushed per head per diem of 24 hours ranges from 18 hundred weight to 3 tons 3 quarters. The number of holes per square inch in the gratings used is from 64 to 140. The horse-power required to work each stamp-head is fromin 0.66 to 2. The quantity of water used per stamp-head in crushing varies from 4,000 gallons to 8,640 gallons per diem of 24 hours. The quantity of mercury used in the ripples per stamper is from 10 to 40 pounds. The quantity 206 MECHANICAL APPLIANCES OF MINING. of mercury lost per stamp-head per week varies from ~ ounce to 5S ounces. In the Maryborough mining district the stamp-heads and shanks or lifters vary in weight from 4 hundred weight 2 quarters to 8 hundred weight, and the cost from ~4 18s. Gd. to ~8 14s. 6d. The height the stamp-heads fall varies from 6 to 22 inches. The numnber of strokes made by stamp-heads per minute is from 50 to 75. The quantity of quartz crushed per head per diem of 24 hours ranges from 1 ton to 3 tons. The number of holes per square inch in the gratings used is from 70 to 144. The horse-power required to work each stamp-head is from 0.50 to 2.50. The quantity of water used per stamp-head in crushing varies fromn 900 to 8,640 gallons per diem of 24 hours. The quantity of mercury used in the ripples per stamper is from 3 to 30 pounds. The quantity of mercury lost per stamp-head per week varies from 13 ounces to 8 ounces. In the Castlemaine mining district the stamp-heads and shanks or lifters vary in weight from 4 hundred weight 2 quarters to 8 hundred weight, and the cost from ~4 2s. 6d. to ~21 11s. 6d. The height the stamp-heads fall varies from 6 to 15 inches. The, number of strokes made by stamp-heads per minute is from 35 to 75. The quantity of quartz crushed per head per diem of 24 hours, ranges from 1 ton to 3 tons 5 hundred weight. The number of holes per square inch in the gratings used is from 40 to 144. The horse-power required to work each stamp-head is from 0.50 to 2. The quantity of water used per stamp-head in crushing varies from 4,800 to 12,960 gallons per diem of 24 hours. The quantity of mercury used in the ripples per stamp is from 6 to 40 pounds. The quantity of mercury lost per stamnp-head per week varies from - ounce to 24 ounces. In the Ararat mining district the stamp-heads and shanks or lifters vary in weight from 5 hundred to 6 hundred weight 3 quarters, and the cost from ~7 to ~8 8s. The height the stamp-heads fall varies from 71 to 10 -inches. The number of strokes made by stamp-heads per minute is from 60 to 72. The quantity of quartz crushed per head per diem of 24 hours ranges from i ton 5 hundred weight to I ton 10 hundred weight. The nulmber of holes per square inch in the gratings used is from 90 to 120. The horse-power required to work each stamp-head is 0.75. The quantity of water used per stamp-head in crushing varies from 4,320 gallons to 12,960gallonslper diem of 24 hours. The quantity of mnercurv used in the ripples per stamp is from 6 to 47 pounds. The quantity of mercury lost per stamp-head per week varies from ~ ounce to 7 ounces. In the Gipp's Land mining district the stamp-heads and shanks orlifters vary in weight from 6 hundred weight to 7 hundred we ight 2 quarters, and the cost from ~5 5s. to ~40. The height of the stampheads fall varies from 7 to 10 inches. The number of strokes made by stamp-heads per minute is from 60 to 80. The quantity of quartz crushed per head per diemn of 24 hours ranges from 1 tonll 10 hundred weight to 2 tons i hundred weight. The number of holes per square inch in the gratings used is from 70 to 259. The horse-power required to work each stamlp-head is from 0.75 to 1.50. The quantity of water used per stamp-head in crushing varies fromn 1,600 gallons to 25,000 gallons* per diem of 24 hours. The quantity of mercury used in the ripples per stamp is from 10 to 37 pounds. The quantity of mercury lost per stamp-head per week varies from, ounce to 32 ounces: * This is excessive. STAMP MILLS. 207 It will be interesting, also, for comparison with our own statistics, to note the present number of machines in use in Victoria, Australia, for different mining purposes. The following statement shows, approximately, the number of miners employed, the machinery in use, and its value in the several gold fields in the colony, &c., compiled from the mining surveyor's and register's reports for the quarter ending September, 1869. The number of miners (including 16,393 Chinese) engaged in alluvial and quartz mining was 68,684. Machineryfor alluvial mnining.-Steam engines used in pumping and winding, 422; horse-puddling machines, 1,797; whims, 292; whips or pulleys, 310; sluices, toms, and sluice-boxes, 18,740; hydraulic hose, 13; pumps, 992; water-wheels, 303; quicksilver and compound cradles, 281; stamp-heads crushing cement, 652; boring machines, 21. In quartz mining.-Steam engines used in winding, pumping, and crushing, 656, with an aggregate of 12,308 horse-power; crushing machines, driven by other power than steam, 67; stamp-heads crushing quartz or other vein stuff, 6,200; winding, washing, pumping, or other machines, moved by water-power, 6; whims, 544; whips or pulleys, 440. Approximate value of mining plant, ~2,219,658. Number of square miles of auriferous ground actually worked upon, 892k. Number of distinct quartz reefs actually proved to be auriferous, 2,808. Weight and cost of stamps, the qanltity of quartz crushed per stamp, ~4c., at some of the principal gold mines in Australia. Compiled from the "Mifineral Statistics of Victorian for 1867. Quantity Name of district. eih Cost of stamps. Fall. lo pe crshe per stamaps. Csminute. stamp in 24 hours. Pounds. ~ s. d. ~ s. d. Inches. Tons. Ballarat-.-...-..... —-- 400 to 850 3 17 6 to 15 10 0 7 to 10 50 to 85 1.0 to 4. 0 Beechworth ---------. 442 to 775 5 3 6 to 13 00 0 5 to 14 40 to 90 0. 8 to 4. 0 Sandhurst..-.............. 500 to 800 4 5 8 to 8 11 0 6 to 18 25 to 75 0. 9 to 3+ Maryborough..-............. 450 to 800 4 18 6 to 8 14 6 6 to 22 50 to 75 1.0 to 3. 0 Castelernaine -.- -—....-. 450 to 800 4 2 6 to 21 11 6 6 to 15 35 to 75 1.0 to 3; Ararat..-.-.-............. 500 to 675 7 00 0 to 8 0 0 7-' to 10 60 to 72 1. 25 to 1.50 Gipps Land.................-... 600 to 750 5 5 0 to 40 00. 0 7 to 10 60 to 80 1, 50 to 2.05 Fineness Horse-power Gallons of water Quantity Loss of Name of district. (Holf res expended per stamp of mercury mercury (oepe perst stamp. per stamp. p'r stamp. sq're inch.) Poundc. Ounces. Ballarat. ------- —.. —. —-- 40 to 200 1. 00 to 2. 00 950 to 8, 640 5 to 75 1 to 8 IBeechworthl.-..-.. —--—....-. 60 to 140 0.75 to 1.50 720 to 11.520 5 to 70 1 to 8 Sandhurst.. - 64 to 140 0. 66 to 2. 00 4, 000 to 8, 641) 10 to 40 + to 51Maryborough -..-.....-.. —. 70 to 144 0. 50 to 2. 50 900 to 8, 640 3 to 30 13 to 8 Castlemaine.-..... ——. —--—. 40 to 144 0. 50 to 2. 00 4, 800 to 12, 960 6 to 40 ~ to 24 Ararat. —-—..-.. —----..-. 90 to 120 0. 75 4, 320 to 12, 960 6 to 47 - to 7 Gipps Land —.-.... —..-.. --.. 70 to 250 0. 75 to 1.50 1, 600 to 25, 000* 10 to 37 1-5 to 32;' This excessive. STAMIP-BATTERIES OF PORT PHILLIP. For the purpose of comparing our methods in California with those in Australia, the following notice of the Port Phillip Company's mines and mill, at Clunes, Australia, is added to the foregoing descriptions. This compatny mines upon five veins, with an aggregate drivage of 25,590 feet, equal to 47 miles. The depth of the main shaft is 464 feet; length 208 MECHANICAL APPLIANCES OF MINING. of tramways on the surface for the conveyance of quartz and refuse, 2,500 feet, single-track; engine for hoisting and pumping at the two shafts, about 85 horse-power. The costs of mining and raising the quartz average about 13s. per ton. The large masses of quartz are passed through rock breakers, of which there are two. The number of stamps at work is 80; of these 56 weigh about 600 pounds each, including the lifter. They give about 75 blows per minute, require about 1 horsepower per stamp, and crush an average of about 2 tons 4 hundred weight per head per 24 hours. The remainhng 24 stamps weigh about 800 pounds each, including the lifter, give 75-Lows per minute, require in the aggregate about 30 horse-power, and crush about 4 tons per head per diem. These stamps have the larger portion of the small quartz delivered to them. The quantity of water required to work the stamps efficiently is about eight gallons per head per minute, being 921,600 gallons per diemn. The construction of the batteries and the method of saving the gold in troughs is shown in the accompanyilng illustration, giving a section through the battery. b is the lower end of the selffeeding hopper, with a spring, - c, below it. Just below this is the water-trough d. The stamp-lifter or stein is made largest at the lower end, so as I 2 Ad~ to be wedged into the headf v__ 9 Oby a key at the side, in this respect being very different from the method of attachmient in California. The head is cast also in one piece, withoX I e out a shoe, and isrenewed when too much worn. The die g is /____\\\\t > 0 H placed loosely in the bottom box or bed h. The delivery is through grates upon both sides of the battery, at e, e. A perforated plate, j, serves k- \ to retain any coarse particles thrown out, and the stamped QQAx ~k~ / f~~~ material, passing through this plate, falls into the mercury Section of the Battery of the Phillip Company, Clules. boxes 7c, k 1, and thence upon a long line of blanket strakes, the extreme upper end of which only is shown in the cut. These strakes are each several inches broad, and there are nine in succession, one below another, with a mercury-box at the lower end, through which the material passes before entering the waste-trongh. This mercury-box serves to catch any fine particles of gold that may have passed the blankets and any stray globules of quicksilver from the upper boxes.* * The amalgam which slowly accumulates in these boxes has been found to be in a crystalline condition, and, according to Mr. George F. Ulrich, the mineralogist, contains only a small percentage of quicksilver, with a relatively fixed percentage of gold, and forms true crystals, which, under the action of nitric acid, do not become loose and spongy, but take the appearance and lustre of solid gold crystals. They are usually in modified and distorted octahedra, and are sometimes prismatic. STrAMP MILLS. 209 STAMHP-iMILLS IN BVrZAZIL. The stamp-mills, carrying in the aggregate 135 stamps, in Ise at the MIorro Velho mines in Brazil are constructed lupon the Cornish pattern, except that each lifter has four iron guides to keep it in position. When new, one of these stamp-heads weighs 230 pounds, and when worn-out only 59 pounds. The average weight may be considered to be 150 pounds, and the duration about four mlonths. The total weight of the stamp, with lifter, shank, &c., is about 640 pounds. The battery-box is made of wood and lined with sheet-iron. The distance between the heads and the sides of the coffer is about three inches. The batteries are self-feeding. The grates are nineteen inches long and nine inches wide, and are made of sheet-copper, pierced with conical holes one-twelfth Of an inch in diameter outside and tapering to one-forty-eighth of an inch on the inside. These copper plates are found to be, on the whole, more durable than iron. Further particulars of practical value mtay be obtained from the following tabular statement, given by Mr. J. Arthur Phillips, from. the manuscript notes of Mr. F. Dietzsch,ll the snperintendent of the reduction works: amvber and72 dimensionL'i of stamp2) mills at the 3Morro relho 1cs~, Bcrazil. DIMIENSION OF STAMP DIMENSION OF ORE STAMPED. COFPIERS. i WHIEELS. _ <. 1Th5rod1c oif stamln lmills_ r s di -t ed F tr t. Ft. igtn. i nc Fte i n. rfi, Ft. Int. Ir. Lyon O. —-------- 0 63 0 o n 2 I 3 2 0 40 6 3 f3 3&. 73 t i. ds t2, 733 CotesTorthl. 1 — 2- -. I0 3 10. 4l 3 15i8 S amnh a 126 1231132 19 2 4 4 10. 94 1. 2I1 2,710 wIth 71ilen. ha o24 |78 12 f i 42 s6 6 0 6 34a -G 1. 44 3, 225) Pow\hs --------- 36 67 12 4 | 2 2 1 3 1 10 51 0.a 0 66.10 1.83 4, 100 VAddiso )Im...4 73 1 1 4 2 2 1 3 1 1 10 I2 0 6 0 3.54 1.48 3, 215 The poinoduct of staervnpl i ssainr froin thle gnraes 1ia front is dis utes withn clean water as it runs, an1 is colnducted overf incllined tables or strakes about eighltee inches wid( and from twentl-seven to thirty-fihve. feet in lengtsh, withl a fall of one ilch per foot. Bulloels' hidces, talnned -with the hair on, are spread over the first sixteen feet of these strakes, and baize cloths are placed below, fllonwed again by another series of overlapping skins. These skins and strips of baize are washed at regular intervals in sepnarate tanks. tlhe deposit on the first three skins is known as head-sandll, and amnounts to 0.42 of a cubic foot per ton of ore stamped. This sain w goes to the a:Lnalgamnating house. The sCnmiddle sand,' fron sklins Nos. 4 ad 5 contains some six ounces of gold per ton, anid is further enlriched by beingT waslhel over another system of strales. The prfoducts below the fifths skin are kInown as "tail-salnd,'7 and are sulbjected to further concentration. "M 34r. Dietzsch relnarks that stra:king mnay, on the whole, be considered a cllheap, simple, and economical process, by which 67 per cent. of the gold origicnally p:resent in the ore is obtained in a highly concentr;ated state, while the 33 per cent. wrhich. escapes is in two distinct forlml s-first, ligwolht fee giol; sc(iddg g01d inclosed in the coaarser particles of pyrites." 14- 3m 2 10 MECHANICAL APPLIANCES OF MINING. The dimensions and products of the strakes are given in the annexed -table: Dimeiisions and products of strake.s at the MIforro 111ho JMilcs, Blrazil. a a I NI Names of stani 1 n lls. - 5 6 l l IFt. In Ft. I. S. ft. Lyon. —. —-- --.- 30 1 36 31 10 1 6 1 719 46 83 36. 73 288 210 20. 00 Cotesworth —...1 12 13 30 6 1 41 545 32. 21 16. 92 104 65 5. 50 Susannah. —. 9 8 27 0 1 6 324 9. 61 10.94 48 48 2. 75 Herring..-......-.'.-.. 24 29 35 0 1 6 1, 232 35. 64 34. 56 228 174 18. 00 Powles.-...-...-..-... 36 42 33 7 1 3.- 1, 821 27. 55 66. 10 336 252 28. 47 Addison-................. 24 30 31 10 1 5 1, 352 38. 04 35, 54 240 170 17.00 Tota-...............- 135 158 ----—. ----- 6,993 -. 200.79 1,244 919 91.72 TH''E GERAN STAMP BATTERIES. In Germany the round stem revolving stamp has not been introduced. Square stems of timber with square heads are the most common, and the earns are usually short projections from a large cylindrical wooden shaft, lifting the stamp by catching under a projecting tongue. The stamp sterns are also made of rectangular iron rods, either single or bolted together, and secured to the square shank of the stamp-head and shoe (all in one piece) by means of bolts. The head is about six inches square and nine inches high, ranging with the weight desired for the stamp. The mortar-box or coffer is made of planks lined with sheet-iron,* and the bed usually consists of stamped quartz pounded iii by the stamps or solid stone, or, better, of heavy cast-iron dies or anvils as long as the bottom of the mortar. These dies are simply rectangular masses with plane surfaces, and the upper die is four inches thick. As a very firm and even foundation for it is necessary, it is found best to place it on another mass of similar form but heavier, from six inchles to twelve inches high. In the cross-sections of batteries given beyond, these iron dies are seen at g and g. The lower of the two masses rests directly upon the ends of blocks of wood or upon heavy timber, which is supported upon crosssills still lower, and these in turn upon masonry. When it is intended:that the battery shall stand independently of the frame of the building,:the foundations are carried to a greater depth. The upper iron block or die of course is subjected to rapid wearing, and it is generally ally allowed to wear oft for one and a half inch before it is turned over. When it has been worn out to this extent on both sides it is reduced to a plate only:(an inch thick, and is then broken up. These dies do not fit tightly between the sides of the mortar; a little space is left, which is filled by wedges, and when these are removed the die can be easily turned. For convenience of handling they are made with short projections at the ends. Iron is beginning to be used to some extent for battery franmes and mortars, and Rittinger gives figures of end-posts, intended to receive wooden sides, being cast with vertical grooves for the purpose. Into these grooves the planks designed to form the mortar boxes can be fitted and then secured by drawing up the posts by bolts. The posts rise high' The reader, inclined to wonder that batteries so ingenious and well-constructed in some other respects, still retain the wooden mortar, should remember that they are not,built for crushing gold ore, and hence perfectly tight mortars are not required. STAMP MILLS. 211 -enough to receive cross-pieces above, and at the base are expanded into three horizontal branches or feet so as to form a firm base by which the whole is bolted down to a massive foundation of masonry. It does not appear that the California system of anchoring the battery frame to masonry or heavy cross-sills is in use abroad. On the other hand, the timber frames of stamp batteries are frequently united with the framework of the building in which they are placed. In the Revue de l'Exposition 4, page 154, mention is made of stamps constructed entirely of metal at Silberau near Ems, and shown by a working model at Kalk. A figure is also given which represents the stein as round and very light, with a screw-thread cut at the top, upon which the iron tappet is screwed like a nut. This method of attaching the tappets was formerly used in California, but it has been abandoned since the introduction of the "' gib-tappet " already described. OVERFLOW BATTERIES. The overflow or float battery is the simplest form, and is madle with numerous modifications intended to insure the best working results. The overflow may be along the whole front of the mortar-box, or at the ends alone, or at the front and ends; but in practice it is generally confined to the front and to two forms of the float battery: 1. That with the unobstructed overflow, the stamped stuff with the water being car-:ied over the edge of the fIront wall of the mortar; 2. The partition overflow battery, or Schubersatz, in which the overflow is obstructed by a partition descending below the surface of the water in the battery, leaving only a narrow slit or space through which the water alld materials can flow out. Batteries of the first form are made with the overflow from 8 to 15 or 18 inches above the bed, according to the fineness of the stuff required, being from 15 inches to 18 inches when particles of one millimetre in diameter are to be produced. For coarser materials, the height may be diminished to 8 inches, and with this height particles five millimetres in diameter will be delivered. The amount of water required for each stamp varies from four-tenths to eight-tenths of a cubic foot per minute. T']he swash in an open overflow battery will always carry over more or less of the coarse unrcrushed firagments, particularly when the height of the discharge is not great, and it is to obviiate this difficulty that the partition float battery has been devised. In this form of battery the discharge takes place through a long and narrow slit, opening in the mortar at a height of four or five inches above the die, and extend- ing outward and upward to the height which would be required for the discharge edge of an open battery. In the annexed figure, which is a section of the front part of a mortar made of wood, this opening may be seen, extending from just above the surface of the broken ore, upon g upward to the top of the trough. The wall or partition between this narrow space and the interior of the mortar-box is so fitted in that it can be taken out in order to clean the mortar or remove any obstruction that may have lodged in the opening. If the slit is placed too low in the mortar it is liable to be choked. It should not be less than three inches above the die. It is also important not to have the opening too large, as the velocity of the upward flow of water yould then be diminished, and would not be sufficient to carry out. 212 2 MECHANICAL APPLIANSCES OF MINING. the pulp without the use or a much greater quantity of water ttan is desirable. It is evident that the quantity and fineness of the stuff delivered by this outward flow of water inmay be regulated by the supply admitted to the battery. The consumption of water for such stamp, with a three-quarter inch slit, varies from two to three-tenths of a cubic foot per minute. GERMIAN SCREEN BATTERIES. In the German screenl batteries, the screens are placecl in the front, generally at a height of six inches K771/i;' above the die, and rarely at three inches when the |1 ~~ W mg quantity of water is great. The figure is a section of the front of such a battery, showing a method of holding the screen S in place by.. means of a frame. Aln opening of the length and breadth of the screen, is cut out of the planking of the front of the mortar-box, and a rectangular iron frame is bolted or screwed on to the inside of the box ~ _ i,:and projects so as to forlm a shoulder three-quarters of an inch wide all around the opening. The screen be+ g 1:~1 ilng placedl in the openling fits against tllis projection, l'.'ii and is then held tightly by another frame or follower - which is movable and swings from hinges above, and i provided on its lower edge with a projecting ear,:~,:j" tthat fits over a staple through whlich a wedge is driven to hold the frame securely in its place. With this construction it is practicable to place the trough _. for supplying water in the front instead of at a I.La —.:-;- the back as is usual. In " ~'L this figure the two an. vils or blocks of cast-iron are seen at g andcl'. The impurities of water flowing through 4 the battery, es)ecially floating objects such' as sticks, grass, and the like, tend to gradclnally close up the meshes or holes of the L screens, and thus, by) preventing the free / exit of the crushed stuff, to diminish the product. In order to prevent this, the form known as the Stcausatz, or stay-battery, has been devised by Rtittinger. It; consists essentially inl backing water up against the front of the screen, so thoat<>\ -i& the piston is replaced I ( i - from a reservoir, W, at the back of the apparatus. According to Rittinger, experience has shown that the duty of self-acting machines of this kind is generally three times as great as Continuously-working Jig-Harz. that from the ordinary intermittent working apparatus. CONTINUOUSLY-WORKING JIG-HARZ. In 1863 Mr. Geyer, an engineer from Baden,: 1 introduced continuously-working jigs into the gre at ore-dressing es-:; tablishment erected by ______ _ _ 1ie ihim on the banks of the Lahn. In the construction of these machines,~~~~_'_ " both wood and metal — F ~~~I #lwere employed. The arrasngement of the parts f is represented by the ac-,~~ 1.:; coinpanying figures.'Ii.k ", \ x It is a double machine,....' —' composed of two grates and two pistons, actu-!|J —-.. l~ated simultaneously by means of cranks on a.........~ shaft above, the motion Continuously-working Jig-section through piston. being communicated by two connecting rods. The grates are inclined forward, and are provided CONCENTRATORS AND SEPARATORS. 235 with a crevice or gutter at the lower edge, through which the concentrated ore falls into inclined troughs c. The stuff passes from one grate to another, and thus two different grades of fineness may be secured. Iron plates or partitions are placed so as to govern the discharge, and these may be raised or lowered at pleasure by the thumb-serews e e. These machines, worked at seventy strokes per minute, will wash about nine cubic metres of stamp stuff, diameter of Om.005, in a day, and they require about 300 litres of water. HUET AND GEYLERI'S SELF-ACTING JIG. Messrs. Huet & Geyler exhibited this form of jig at the Paris Exposition in 1867, and its satisfactory operation upon lead ore was witnessed by the writer. It is constructed of cast iron, and is very compact. Most self-acting jigs require a large quantity of water, and this in many localities is a great objection to their use; but this jig is designed to work with but little loss of water, and, at the same time, by the aid of an automatic scraper, to increase the product. I?, Automatic Jig of Huet & Geyler. The tub is shaped like the letter U, and is divided into two compartments, one for the piston and the other for the working grate. Water is supplied through the valve A, at the side, and the fine stuff or slime which falls through the sieve settles upon the botton, and is discharged through an opening, B, controlled by a lever reaching out to the front of the apparatus. The piston is operated by means of a shaft and crank, which works in an inclined slide, C, connected with a lever carrying the piston, so as to give a rapid descending stroke with a period of rest at the bottom, and then a slow upward movement; thus giving the most 236 MECHANICAL APPLIANCES OF MINING. favorable conditions for the rapid and perfect separation of the stuff upon the grate. The motion of the piston may be varied at will, in order to secure the best flow or motion of the water for different grades of ore. This adjustment is effected by shifting the position of the head of the piston along the lever or arm, and by this means increasing or diminishing the amplitude of its motion. The construction of this slide is shown in the figure. By turning the fixed screw s s, the head of the piston may be moved forward or backward. Act ^ > The machine is provided with a /iWX (O\ I\ \\\ ~\\ 9 scraper R, actuated by the long rod D, which is attached to an eccentric on the main shaft and moves the levers E and F, giving to the scraper a forward and backward motion over the top of the stuff upon the grate, and throwing out a portion of it at each movement. The path of the scraper is determined by the guides G, attached to each side of the tub. It can be varied by means of screws upon the lever or arm F. In passing blackward, the roller or prqjection on the scraper, which follows the guides, rises upon the movable inclined plane G, and on its return passes below this plane, following the double-dotted line in the figure. The poor stuff from the top, which is constantly thrown forward and off by this scraper, falls over the front of the tub at R, along the chute M. The grate is inclined as in the machine of Rittinger, and the opening for the escape of the heavier and rich portion is similarly placed at the foot of the incline and just below the bridge over which the poor stuff is scraped. The opening is shown at II. It is closed by a valve which extends along the whole front edge of the sieve, and can be opened and closed at pleasure by a lever. The stuff passing through this valve falls into a receptacle K, from which it may be removed at pleasure through the opening L. The scraper is so made of perforated sheet-iron that it does not throw the water out together with the waste. These jigs are made with great care and accuracy, and work in a satisfactory manner, as the writer assured himself by personal inspection of the machine in operation near the Champ de Mars, in 1867. KROXMS DRY ORE CONCENTRATOR. This machine may be called an air jig. Dry ore in powder or coarse grains is subjected to sudden piffs of air from-below, through a grate, precisely as water is forced up through a grate in the pump jigs. In this machine the dry ore is supplied automatically upon a horizontal sieve, and the concentrated portion is discharged upon one side and the refuse upon another. It consists of a receiver, to hold the crushed ore; an ore-bed, on which the ore is acted upon; gates, to regulate the flow of ore from the receiver and the depth of ore on the ore-bed; bellows, to give the puffs of air; a trip-wheel and spring, to operate the bellows; and a ratchet-wheel and pawl, to operate the discharge roller. There are six projections on the trip-wheel, and therefore the moderate speed of 50 to 70 revolutions per minute of the trip-wheel shaft gives 300 to 400 movements to the bellows, and a corresponding number of puffs of air. This rapidity is a great advantage. The use of water in conceLn CONCENTRATORS AND SEPARATORS. 237 tration admits only from 50 to 80 lifts per minute, while in air from 300 to 400 are, obtained. This is due to the fact that bodies fall much more rapidly in air than in water. The sieve or ore-bed is made of wire gauze tubes, placed front onequarter to one-half of an inch apart, according to the kind or grade of ore to be treated. The concentrated ore settles down in openings between these tubes, and accumulates in a reservoir from which the discharge is regulated by a roller, so as to keep it filled and thus form a support for the upper layer of ore to be acted upon. The experimental working of this machine is certainly very satisfactory; and it is claimed for it that it will accurately separate zinc-blende from galena-a severe test. The machine measures five feet by two feet, is three feet ten inches high, and weighs about 800 pounds. SEPARATION OF ORES BY FALLING THROUGHi A COLUMN OF WATER. Yarious forms of apparatus have been devised to effect the separation of the grains of either coarse or fine stamp stuff having nearly the same volume, but differing in density, by allowing them to fall through a column of water either at rest or A in motion. Such machines may be regarded as modifications of the jig; a greater length of fall of the materials in water being substituted for a succession of short falls, the result of the repeated shocks or jerks given to the sieve. Apparatus of this kind forms a connecting link between jigs and the slime separators. These machines depend fur their operation upon the difference in the time required for particles to fall through a given height of column of water, which, for particles of equal size, is in the order of their specific gravities. As the time required is modified by the bulk of the particles, a careful sizing is an essen- p tial prerequisite to the success of this form of concentrating apparatus. One of the simplest forms is a stationary cylinder, designed by Messrs. Huet & Geyler, and exhibited at the Exposition in Paris, - 1867. It consists of two stationary concentric cylinders, E and I, kept full of water by means of a supply pipe T, while al portion of the water escapes through the opening in the conical bottom C, and the excess overflows at G, around the top. Directly below the aperture in Huet & Geyler's Separator. 238 MECHANICAL APPLIANCES OF MINING. the bottom of this cylindrical vessel, a receiving tub B is placed, so as to receive the water and ore that fall through. This tub is divided into compartments and rotates around a central vertical axis. The stuff to be concentrated is supplied at intervals at the top of the cylinder I, at A, and falls in the direction of the arrow. In falling through the three feet of water, the particles separate according to their specific gravity, and the heaviest arrive first at the outlet and are caught in one of the compartments of B. As the next grade of ore reaches the outlet, the tub B has turned so as to bring another compartment under the orifice, and the stuff' is thus classified. The revolution of B must be carefully timed to the rate of descent of the particles and the interval of the periodic changes. The following tabular statement shows tihe time required for the fall of stamp stuff of different minerals, and of different diameters: Size of thle Pyrites Carbonate of Galena, Pyrite arytes, Blende, Quartz, gravel gravity 4.60 liae, gravity 7.56. gravity 4. 50. gravity 4.15. gravity 2. 70. in millimetres. to 5. 00. gravity 2. 60. From to Seconds. Seconds. Seconds. Seconds. Seconds. Seconds. 30. 00 18.00 0.90. ——..... —--. —-.... —-- -. 2. 36 18. 00 7. 00 1.11..... —-—....... —------....-. — 3. 67. 7. 00 5.50 1. 50 -.... —-—. —... —-—......... —-. 4. 61 5. 50 4. 44 1. 84................................. 6. 10..... 4. 44 4.17 2.03 52. 54 2.81 2.88 7. 27 3.86 3. 94 3. 67 2. 48 3. 43 3. 73 4. 61 7. 61 5.56 2. 77 2.50 3.11 4.41 5.55 6.53.............. 6.83 1.77 1.50 4.14 6. 21 8.30 9.78. —-—..... —. 10.17 1. 00 5. 27 10. 36 11. 33 11. 67 14. 64 17. 21 This table shows that the velocity of the receiving tub must be proportioned to the size of the particles of the stuff to be separated and to the height of the fall. For a height of Im.00, the number of revolutions of the tub per minute must be, for particles of Om.016 in diameter, 21 revolutions; 01m.004, 11 revolutions; 0m.001, 6 revolutions; Om.00025, 2.7 revolutions. This apparatus has not yet been long enough in practical operation to prove its value, and it requires to be studied and experimented with further before the results will be satisfactory, yet it has already been fou:nd that a thorough classification of the stuff is essential; that the feeding and the motion of the rotating tub must be regular; that the grains which separate best are those between Om.004 and Om.01 in diameter; and that with fine stuff the results are incomplete. When the particles are 0m.011 in diameter, and have a density of 3.15, they will precipitate from compartment to compartment, in the following order: First compartment, density, 4.2; 7 per cent. Second compartmlent, density, 3.2; 52 per cent. Third compartment, density, 2.9; 24 per cent. Fourth compartment. density, 2.9; 12 per cent. Fifth compartment, density, 2.9; 3 per cent. Sixth compartment, density, 2.8; 2 per cent. For the particles of 0Om.014 inll diameter, the proper number of turns is three and a half, and for particles of 0m,.004, five turns. One of these contrivances will deliver about 750 quarts of gravel per hour. CONCENTRATORS AND SEPARATORS. 239 HIUNDT7S SETTLING TUB. lHundt's settling tub operates similarly, but differs in this, that the receiving tub is fixed, and the water column is made to rotate. The ore is not supplied in the center of a column of water, but into an annular or cylindrical column in a continuous stream, differing in this respect also from the first described apparatus. It is a continuous working machine, designed to separate or sort the particles according to their velocity of fall through the column of water. The particles of stuff entering this machine are subjected to two motions, the direct fall due to gravity, and the movement of translation due to the motion of the water. It follows that they take a diagonal course and reach the bottom at different distances from the point at which they entered the column. This apparatus was first used at the Landerkrone mines, near Wilnsdorf, in 1854. It consists l of a circular tub, within which an open cylinder is supported and made to revolve by a vertical shaft. This cylinder is partly closed by means of S a cone, so adjusted that only an annular opening is left, 5 centimetres wide at the bottom, and 13 centimetres at the top. The outer tub is lm.75 in diameter, and is 2 metres high. The inner cylinder is lm.60 in diameter. Small partitions, s s, between the cone and the cylinder serve to carry the water filling the space around with the cone. and cylinder during their rotation. Hundt's Settling Tub. The stuff to be treated is introduced in a continuous stream at the top, and in falling through this height of two metres of water, and being at the same time carried around by the revolution, is classified according to the rapidity of the fall of the particles. It may be withdrawn from the vessel by suitable openings around the bottom. By careful management of these openings, very little water is lost; and this economy of water, and the very small quantity required for the proper working of the apparatus, renders it especially worthy of the attention of mill-men and metallurgists, in such regions in New Mexico, Arizona, Nevada, and Sonora, where water is scarce. The number of revolutions of the drum should range between 2 and 6 per minute, the diameter being 4 feet, and the size of the grain from - to ~ of an inch. Used with ore-stuff particles of which differ in size, the machine sorts these particles according to their rate of fall. As the product in such a case would consist of small and dense particles mingled with larger ones of less specific gravity, the separation can readily be effected by the simple operation of sifting. RITTINGER'S SETZ-RAD. The apparatus of Rittinger is upon the same principle as llundt's, and it is not clear which was s uggestive of the other. It is a self-feeding continuous working machine, and consists of a stationary wooden tub a a, the bottom of which is divided into eight conical compartments connecting with pipes c, which, after descending for a short distance into the foundation, turn upward and outward, and are curved at the end so as to deliver the water from'the tub into an annular trough d. A double cylinder,ff, supported by a shaft, g, is made to turn in the tub a. The stuff to be separated is delivered in a constant stream through the hopper and distributor k into the revolving cylinder, and falling 240 MECHANICAL APPLIANCES OF MINING. through the water in this space is sorted and collected in the conical reservoirs and tubes b. A branch tube, closed by valves s s, permits the removal of this concentrated stuff from time to time. The waste stuff, delivered through the tubes b into the annular trough d. flows into another trough or conduit mib, whence it is lifted by the wheel n, and returned to the tub oa. f.,/'"'; t S a I1.R./At Settling apparatus of Mr. de Rittinger. Rittinger in his Anfbereitung describes a machine of similar construction? in which the stuff is not received into an annular column of water, but into an ordinary tub in which the water is made to revolve by a wing-wheel, the wings of which would correspond in position to the sections of the cylinder ffin the last figure. The bottom is divided into eight radial compartments ending in funnel-like cavities, as shown. With grains of lead ore 3 —1 of an inch in diameter, 91 per cent. of all the lead-ore contained in the stuff will be delivered into the second compartment at the bottom, and 8 per cent. in the next. But with grains.32 of an inch in diameter, only 75 per cent. will be found in the second, and 20 per cent. in the third compartment. SLIME SEPARATORS AND SORTING BOXES. A convenient and effective form of the cone apparatus is here shown on a scale of e the upper cone in section. A complete series is usually composed of live or six, arranged in succession, one below another, as shown. The constrtuction is very simple; and they can be made of castiron, so as to be very durable, and at the same time exact in form. Each part consists of two cones, one inserted in the other, so as to leave an annular space in which water flows upward from a reservoir or chamber at the lower, or pointed end. The stuff to be concentrated is conveyed by a launder into the upper cone, and, passing through holes, encounters the upward current. The largest of the stuff so fed should not exceed three-quarters of a millimetre in diameter. The lighter portions are at once carried upward and over the upper edge of the inner cone, and CONCENTRATORS AND SEPARATORS. 241 fall with the escape-water into an annular trough, by which they are conducted away to the next lower cone, while the particles of suifficient weight to resist the current fall through it, and accumulate ill a small Conical Separators. inverted cone, in the chamber below, from which they are allowed to drop by the small aperture at the apex in the direction indicated by the arrow. This orifice is controlled by a valve, and can be regulated at will, according to the rapidity of the accumu-lation. So, also, by means of a screw above the upper cone, the distance between the cones can be regulated according to the necessities of each case. The apparatus requires considerable water, and the overflow from one cone is carried to the next, and so on in succession. RITTINGER'S SEPARATING TUBS WITH ASCENDING CURRENTS. This is another modification of the conical tubs or pointed boxes, but the shape is rectangular, and the water current is not confined to a narrow zone or space between partitions. This form consists of a succession of deep trough-like depressions placed edge to edge, and gradually increasing in size and depth. But as the ends and sides are the highest, the series forms, in reality, but one vessel, the water covering all of the intermediate edges, and thus permitting a continuous flow from one end to the other. This will be seen from the inspection of the figure. Seven compartments, B B, are shown, and the direction of the flow from C to WVr is indicated. The whole series is supported upon a frame at such a height that the attendant can pass under it, and reach the openings at tile apex of the pyramidal tubs, at AA, where the concentrated stuff flows out. A supply-pipe, P P, delivers clear water into each compartrnent through a branch pipe reaching nearly to the bottom. The stuff entering at C deposits the heaviest particles, and, aided by the ascending flow of water from the pipe, the lighter portions pass over into the next tub, and so on. The flow of water into each compartment must be carefully regulated. As the size of the compartments increases, the as16 X 242 MECHANICAL APPLIANCES OF MINING. cendiung current has less and less force, and finally only the very lightest and poorest portions are carried away. The arrangement gives very satisfactory results. It requires from 120 to 150 quarts of water a minute, and will separate about a ton of battery pulp in each hour. It may T. g t-I < be constructed either of wood or of iron. Qa~'1 The apparatus shown in the figure is made ii,. of iron. __ j~ 1 RITTINGER'S CONTINUOUSLY-WORIKING.1STOSSIIEERD. This is another and important machine for concentrating by the flow of the stuff over a plane inclined surface. It has, in addition, a percussive shock, given laterally at right angles to the flow, and not'- L-' — — D'~ t, parallel with it, as in many of the inclined f tables, an(l, for example, in Hunter's concentrator. t, consists of a wooden table or plat-.9 form, about eight feet long and four wide, suspended at the four corners, and inclined 8 forward so that water and fine stuff poured upon the upper part will flow evenly down., -', _____. 1 to the front edge. A lateral throw and A. i r!OEr, -,S1 percussion is given to the whole table by m neans of cams, c, upon a shaft at the side,, and the reacting wooden spring S upon the opposite side of the table. Two tables are usually combined in one, and they are sepg aiated by a narrow strip of wood extending._'; the whole length; similar strips are placed I1 on each side of the table, and serve to keep. the water and stuff from flowing off. The. stuff to be washed is delivered upon the tables at the upper left-handl (,orner, at A. The distributors P P P furnish clear water. While the table is at rest, the tendency of 1z1 1 2 fX the stuff is to flow down the slope in a direct line from A to A'. By means of the lateral percussion, however, the path of the heavier particles is changed, and they are gradually thrown from left to right, along the surface of the table, at right angles to the direction of the current of clear water. ___,____ +This current tends at the same time to sweep |!L__ ]:i{' E -) the particles downward, and it acts upon -~~' —-' ~-_~_' 1 the light sterile matters more rapidly than upon the heavry ore. iThe result is, that A, V the heavier and richer particles are gradually separated from the poor stuff and de- scribe the path upon the table indicated by the dotted lines. By the time the particles have reached the foot of the table, the richest portions have been transferred to the corner of the table CONCENTRATORS AND SEPARATORS. 243 diagonally opposite to that upon which the stuff entered, and they flow off into the compartment E. The "' middlings" are dropped into the next compartment D, and the poor falls into C. I. L ___.. 1 7 Rittinger's Con.tinuously-working Stossheerd —front view. L________ _oo_ o__ _szew. I.& W-!.;iv'.'xJ02- L~~g gi H sS~~~~~~~ = ii Rittinffler's Contonuousl:-svorkil tshedve ru +oe 244 MECHANICAL APPLIANCES OF MINING. In order that good results may be obtained with this apparatus, the following conditions must be observed: 1. The surface of the table must be very smooth. 2. The length must be about 2m.50, and the width from lm.25 to Im.50. The width of space over which the stuff is delivered must be from Om.20 to 0m.30. 3. The inclination of the table must be in direct ratio. to the size of the stuff to be washed For sand, it requires to be about six degrees, and for fine powders about three degrees. 4. The amount of clear water to be admitted at the top? of the table, and to be spread over a width of from Om.30 to Om.35, will be nearly constant. For sand, about six quarts. a minute is necessary; and for dust, or fine stuff, from three to three, and a half quarts. If the, slope of the table is diminished, and the size of the stui fremains the same, the quantity of water should be increased. It is necessary to distribute this supply of water quite near toi the stuff to be washed, so as to facilitate the separation of the light and poor stuff from the rich. 5. The number of shocks per minute should be, for sand, from 70 to 80; for dust, 90 to 100; for poor and fine slime and dust it is sometimes advantageous to carry the number of shocksor jerks, as high as 120,.and sometimes 140 per minute.. 6. The tension of the spring is equal to 100 or 112 kilogramimes. The amount of movement necessary to produce the requisite vibrations is, for sand, Om..065; and, for dust, Om.020. to Om-013. 7. The velocity of the current upon the table should be from 0m.25 to Om.15 per second, according to, the nature of the stuff., 8. The greatest regularity must be observed in the number of jerks or shocks; in the quantity of stuff admitted! upon the table, including water; in the nature of the stuff to be treated; in the slope! of the table, which must be diminished as the stuff to be washed grows poorer and lighter. Careful attention to all these points is essential to success. The apparatus gives' three products. The mixed or middlings can be passed over the table a second time. Stuff of which, the particles are 0m.004 in diameter can be treated as successfilly as the finest slime. It saves much labor. One man can attend two twin-tables. The power required for ten twin-tables is about one-quarter of one horse-power. ROTATING BUDDLES. Two forms of rotating buddles were shown at the Exposition by Messrs. Huet & Geyler, one being concave and the other convex, and both Concave Buddle. made entirely of iron and accurately finished. The construction of the concave buddle is shown by the figure. The stuff to be crushed is ARRANGEMENT OF A COMPLETE MILL. 245 supplied at the circunmference of the circular or annular table, and is discharged into different compartmlents at the centre. The foundation plate sustains the distributing pipe, the water pipe, the waste gutter, and the drivingl shaft. An endless screw upon this shaft gives motion to the concave table. Experience in using this buddle has shown that it is desirable to have a greater number of sprinkling pipes thanl are generally used in the Harz. It is said that the washing of the stuff is completed in one operation, while with the German cionstruction it somletimes happens that the stuff must be passed twice over the machine to obtain an equal result. The convex bucidle is also an annular table, but instead of sloping inward toward the center, it slopes from the center outwardcl, being the reverse of the concave buddle. The stuff is supplied on the inner margin and flows outwnard to the lower edge, alnd is delivered into a succession of annular troughs. The construction is similar to that of the concave buddle. A cast-iron fralue supports the table, the driving shaft, the water pipes, and all the fixtures. The tangent screw and the driving shaft work in a hollow case of cast-iron. ARRANGEMENT OF A COMPLETE SILVER M3IILL. In conclusion I present, by an engraving annexedl a general view of the construction and arrangement of the parts of a complete dry-crushing silver mill, as constructed January, 1870. It hardly needs explanation. The ore received at the highest point falls from one machine to another, and is handled as little as possible. It passes from the dump pile under the car a to the rock breaker b; thence over a sheet-iron drying platform at e to the feed-box d. After stamping it its roasted in the furnace g, and is worked in successive charges in the pan i, froml which it is drawn off into the settlerj, and finally passes through the concentrator K. The amalgam is retorted in a cast-iron retort set in a small furn`ace outside the building. 17 M