MANUAL HYDRAULIC MINING. FOR THE USE Of THE PRACTICAL T. F. VAX WAGENEN, E.M. THIRD EDITION DEVISED. NEW YORK: D. VAN NOSTRAND COMPANY, 23 MURRAY & 27 WARREN STS. 1900. Copyright, D. VAN NOSTRAND CO., 1897. PREFACE. THE following pages are written solely for the use of the practical and working miner, who, while rarely deficient in common sense, is generally unacquainted with the principles of physics and more or less rusty in arithmetical methods. In the daily discharge of his business he is continually confronted with engineering problems of more or less complexity, and com- pelled to depend for their solution trained en- gineering advice being unobtainable or too ex- pensive upon his own limited experience or upon that of his co-laborers. Under these circumstances, errors in con- struction and operation are frequently repeated. The author ventures the hope that the study and use of the following pages will, to some extent at least, obviate the necessity for costly experi- menting, now so common. 3 438587 The Manual does not claim to cover the whole subject, nor to answer all questions in hydraulic engineering. Nor will it take the place of an experienced and competent engineer in impor- tant enterprises. On the contrary, no miner who is not himself an expert, and who can af- ford it, should be without such advice and assis- tance as can be afforded by a well-educated and practised hydraulic engineer. THEO. R VAN WAGENEN, CONTENTS. PAGE. INTRODUCTORY REMARKS, . . .7 CHAPTER I. GENERAL PHYSICAL CONDITIONS, . e .11 CHAPTER II. GENERAL METHODS OF PLACER-MINING, . . 19 CHAPTER III. DIRECTIONS FOR THE MINER, . . . .25 CHAPTER IV. THE PROPERTIES OF WATER, . . .43 CHAPTER V. CONSTRUCTION OF WATER WAYS, . . .51 CHAPTER VI. FLOW OF WATER IN FLUMES AND DITCHES, . . 58 CHAPTER VII. IRON PIPING, . . . . . .04 CHAPTER VIII. NOZZLES AND DISCHARGE, . . . .79 CHAPTER IX. THE SLUICE, . . . . . .82 INTRODUCTORY REMARKS. HYDRAULIC mining is the art of separat- ing gold from gravel, sand, and clay cement, through the medium of moving water and the force of gravity. The process is one lying wholly within the do- main of the science of mechanics a branch of human knowledge now so well understood that results may be predicated with extreme accura- cy, if correct premises are obtained. Hence", ^hydraulic mining presents fewer risks and more certainties than any other department of mining, other tilings being equal. It is sim- ply a question of moving gravel or soil from one place to another. Given, therefore, in addition to an abundance of water to move and wash the gravel, ample space to deposit it again after it lias been washed, and the problem of obtaining a profit is reduced to a minimum. 8 INTRODUCTORY REMARKS. Gold occurs in gravel deposits in a metallic condition. The chemical and mechanical ope- rations required to separate it from the vein substances with which it was originally asso- ciated have all been performed by nature. That wonderful agency has also supplemented her work by again collecting the particles of metal ^wifckifi certain limits, fir-other words,^ cfegrada- tion and erosion of quartz-veins has been fol- lowed by the partial concentration of the mfc apt 90* broken up; and while this operation has ^rr^*^i not resulted in Jwr enrichment of the gold-bear- ing material ifm^-the contrary, it is much poorer, -%nik "for bulk); the metal is placed in association with substances from which it uiagrbe separated e\l with extreme ease and very small cost. A As an example, the gold-bearing veins of the western United States have an average value of about ten dollars per ton of quartz extracted, which ten dollars can be mined, transported to mill, crushed, amalgamated, refined, and sold at a gross cost of about eight dollars per ton, or eighty per cent. The same gold vein, after pass- ing through the laboratory of nature, will consist IN TROD UCTOR Y REMA RKS. Q of a gravel-bed or deposit worth about twenty cents per ton, which twenty cents may be se- cured and marketed at a cost not over five cents, or twenty-five per cent. Other things being equal, therefore, hydraulic mining presents three times the chance for profit that is fountl in gold quartz-mining, and one-third the riskpivith the additional advantage that the extent and richness of ^k^' gravel-beds may be completely studied and ascertained before working Ht, and at a slight cost ; while vein-mining is from first to last more or less of an experiment and '4 chance. \*f) The records of mining show that over seventy- five per cent, of all the gold mined within his- toric times has been derived from the working of gravel-beds. It is also a matter of fact that the area of auriferous gravel deposits is vastly greater than that of quartz-veins. This is es- pecially the case on the Pacific coast of both North and South America. The immense chain of mountains extending from Alaska to Pata- gonia bears evidence of having been at once one of the loftiest and oldest of the great upheavals I O IN TROD UCTOR Y REMA RKS. of geological time. From one extremity to the other it is ribbed with metallic veins, which through the ages have been worn down and away, and their debris deposited by rivers and: i^ses- and glaciers, in all the various ways in which nature works. And these great deposits, consisting of old channel-beds, forsaken bars, grass and forest covered moraines, and sterile terraces, contain, beyond a doubt, more millions than have yet been mined. The great Bine Lead of California, which has been traced for seven hundred miles along the western flank of the Si- erras ; the channels and bars of Montana, which 7&?v/"C-^L represent the pathway of the Missoun^of old; the great morainal deposits of Western- Colorado; /i ated the arid and dry terraces and ravines of A Arizona all these are nature's gold-filled vaults, inviting the enterprise, the energy, and the in- genuity of tfee=3pfe*fee man, and promising, not the irregular and doubtful returns which charac- terize precious-metal mining of the present day, but steady and continuous results, based on an imkustry -as legitimate and safe as agriculture or general trade. CHAPTER I. GENERAL PHYSICAL CONDITIONS. GKAVEL deposits containing gold are gene- rally considered to be the disintegrated remains of mountains which were originally seamed with auriferous quartz-veins, or of strata of rock in which the metal was disseminated, or both. The material forming these deposits consists of gravel, rounded boulders, sand, and clay, gene- rally being in .conformable layers or strata, b.ut at times disposed without regularity. These de- posits are beyond doubt the result of mechanical precipitation. The occurrence of gold dissemi- nated through the gravel is generally ascribed to the same cause, though some are inclined to be- lieve that chemical action has supervened in the case of the metal. The point is one of more scientific than practical interest, though the lat- I 2 fft DRA ULIC MINING. ter theory will perhaps explain why placer gold is purer than vein gold. Gravel deposits may be subdivided as follows : {a) Ancient river-channels. () Recent " " (6-) Bars. (d) Moraines. (e) Terraces. (/) Lake-bottoms (ancient and recent). In general it may be stated that gold will be found in greater quantities and in coarser frag- ments in deposits which are 1. Nearest to the original deposits. 2. Have been deposited on the steepest grades. 3. Contain the most gravel and boulders. 4. Contain the most iron. There are many cases in America, however, where the gold is found almost exclusively in the clay or cement layers, but this does not appear to be the rule. Where gravel deposits are made up of several layers of differently-sized material, often some of these layers are wholly barren, or at least un- profitable. In general the metal is found in HYDRA ULIC MINING. I 3 greater quantities in the lower layers of the gra- vel, near and on the bed-rock. Frequently in exploring and testing gravel de- posits it is necessary or convenient to find the weight of the mass ; this operation will be facili- tated by the following table : One cubic ft. of dry, loose loam weighs 72 to 80 Ibs. packed " " 90 to 100 " " " wet, loose " " 66 to 68 " " " packed' 4 " 85 to 95 " " " solid quartz " 165 " " broken " " 94 " solid limestone " ....170 " " " broken " " 96 " " " fine sand, dry, " 100 to 117 " ordinary gravel, free from cement, and containing no heavy boul- ders (dry), weighs 90 to 100 " One cubic ft. filled with boulders not over six inches in diameter (dry) weighs 95 to 105 " Auriferous gravel deposits are formed on all kinds of bed-rock, such as granites, limestones, slates, and quartzites, and even sandstones. The nature of the bed-rock rarely, if ever, affects the 1 4 H YDRA ULJC MINING. quality of the deposit, though, as will Be seen hereafter, it may affect its economic value. GOLD. The precious metal is of a fine yellow color when chemically pure, and weighs about nine- teen times as much as an equal bulk or volume of water. Hence One culno inch of gold weighs 696 Ibs. One cubic foot " " 1204 " Its value per standard Troy ounce is $20 67, and per pound (Troy) $248 04 In nature gold never occurs pure, but is inva- riably accompanied with some silver, and often with other metals. In this condition it presents a whitish or reddish yellow color, according as the bulk of the accompanying metal is silver or copper. The metal is exceedingly tenacious, malleable, and melts at a temperature of 2,016 deg. Fan. In practice its comparative purity is expressed by the term "fineness," and this is estimated on the basis of 1,000 as a unit of measurement. H ) DRA ULIC MINING. I 5 Thus, a mass or nugget of gold containing 78 per cent, of gold, 18 per cent, of silver, and 4 per cent, of other substances will be said to be .780 (seven hundred and eighty thousandths) fine. In the gravel deposits gold occurs as nuggets (masses of irregular shape and size) ; shot-gold (rounded pellets like very small bird-shot) ; leaf-gold (thin sheets sometimes one-tenth of an inch square) ; coarse flat gold (same size as the latter, but thicker) ; and dust, which is often so fine as to be inappreciable to the naked eye. Occasionally wire-gold is found, but that is rare. The physical qualities of this metal are such that, while it will remain almost wholly intact under the action of chemical reagents, it is easily affected by abrasion, and, if carried for considerable distances together with gravel and ice, is ground rapidly to the finest powder. It does not always follow that a gravel deposit containing even a goodly quantity of gold per yard can be worked with profit. The particles of metal, to be capable of being saved by cheap mechanical means, must possess a combination 1 6 // YDRA ULIC MINING. of weight and shape which will permit the ac- tion of gravity to a. maximum degree. In other words, if the bulk of the gold in a deposit is either in the condition of a very fine dust or very flat, thin scales, it will float away and resist the most careful endeavors to precipitate it. WATER. At ordinary temperatures water is a colorless liquid, weighing about 6&J- Ibs. per cubic foot. At 32 deg. Fah. it becomes a solid, and in the act of solidification expands one- twelfth of its volume. At 212 deg. (sea-level) it boils, and passes ofl: as vapor. Water is slightly compressible at a pressure of 4,500 Ibs. per square inch, but on removal of the force re- turns instantly and completely to its former vol- ume. When expanding under the influence of heat or cold it is capable, as is well known, of exerting enormous force. The following table of equalities will be found at times useful: H YDRA ULIC MINING. I / 1 cubic inch of water weighs 086 Ibs. 1 " foot " " 62.5 " 1 " yard " " 1680.75 " 1 " foot of ice " 57.3 " 1 U. S. gallon " 8.34 The standard measure for water in hydraulic mining is the miner's inch. The quantity of water which will escape from a reservoir through an aperture in its side 1 inch square, whose centre is 6 inches below the con- stant level of the water, is termed a miner's inch. This measure is necessarily a rough one, and has doubtless been often erroneously ap- plied. The aperture should have no tube or conduit leading from it, and its section through- out should be uniform and possess practically no length. These conditions are not, however, at- tained in common practice. The most common illustration of the miner's inch is a hole 1 inch square through an inch board. In this case the length of the aperture is clearly equal to its dia- meter. Where the aperture discharges a large number of inches at once its diameter is of course much larger, and the proportion of its length to its diameter is much less. 1 8 H YDRA ULIC MINING. In round numbers the miner's inch has the following values : Cubic feet. Pounds. U. 8. gal. Discharge per second . .0271= 1.69= 0.2026 min... 1.626 = 100. = 11.99 hour.. 97.56 = 5937. = 711.96 day(12h.)1170.7 = 71250. =8543.29 day(24h.)2341.4 =142560. =17095.78 The miner's inch as a standard of water mea- surement is very defective. In the early days of placer-mining, when the water was owned by one set of people, who sold it in small quanti- ties to another set (the miners), this standard was a necessity. At present it would be better if the cubic foot could be used as a measure, but the change is one impossible to be made. CHAPTER II. GENERAL METHODS OF PLACER-MINING. THE general theory of hydraulic mining com- prehends first, breaking down the gravel ; sec- ond, passing it through sluice-boxes while held in suspension by water; and, third, cleaning up the gold caught in the boxes. The pan, rocker, long torn, sluice, boom, and hydraulic have been successively adopted in al- most every gravel-mining district in America. Unfortunately, exact records of the possible work with each are almost unattainable, and, even if they were, variations in the character of the gravel would to a large extent nullify their value. The following comparative table, giving figures of work performed, first, on ordinary gravel, which is quite tractable, and, second, on cemented gravel, which is perhaps the most re- fractory known, will perhaps be of value to the 2O HYDRAULIC MINING. miner. The two may bo regarded as extremes. The table shows the number of cubic yards of dirt which may be washed per day of 10 hours per man in the first two cases each man work- ing alone, and in the last four in pairs, or economically- arranged gangs : Ordinary. Cemented. By the pan 1 cu. yd. cu. yl. " rocker 2 " 2 ' " long torn... 5 to 6 " 3 to 5 " " sluice 10 to 20 " 6 to 12 " hydraulic .. 100 to 1000 " 100 to 1000 " " boom unlimited. unlimited. It will be understood by every miner that no exact figures can be given in a comparison of this nature, and that the character of the ground will very largely affect the amount of work done. With the pan, which will hold from fifteen to thirty pounds of gravel, only a very little ground can be washed under any circumstances. If the ground abounds in large boulders which can be removed by the hand with ease, a miner will wash twice as much as otherwise. One hundred pans are considered as a good day's work for a careful operator. The HYDRA ULIC MINING. 2 I same consideration that of boulders applies to the work in a rocker and long torn. The latter permits a more easy and thorough break- ing np of cement, and the water generally being supplied automatically, it is operated at a smaller cost. But neither arc adapted for operations on a large scale, nor in any ground carrying less than three to five dollars per yard. The ground -sluice is a device which com- mends itself for banks not too high to cause danger from caving, and when a good grade in the pit can be obtained. The unfavorable point in this system lies in the fact that all boulders must be moved twice, and that no clean-up can be made till the end of the sea- son. In consequence, either the work is pro- longed, with great discomfort to the men, into the period of cold weather, or much water is allowed perforce to run to waste. Whore extensive operations are contemplat- ed the miner has to decide between the boom and hydraulic, or a favorable combination of the two. In California the boom is wholly 22 // 1 'DRA ULIC MINING. abandoned in favor of the hydraulic, and in Colorado it is rapidly being superseded. Yet, as a system of placer-mining, it has many strong recommendations, and. according to some of the best Colorado authorities, is often the superior method. It seems to possess most merits when either the water is very abundant or very scarce. The boom will undoubtedly cave more ground per day and at a less cost than the hydraulic, unless it is a very hard cement. In its opera- lion it is the counterpart of the work of nature in natural ravines. For the purpose of clean- ing off top dirt of poor quality it has no supe- rior, and for ground carrying no leaf -gold it is claimed by some to be greatly preferable. Much depends upon the sluice and the manner of operating it. But where the ground is hard and force is necessary to tear it to pieces, where the banks are low and the gravel tenacious, the hydraulic is, by the testimony of most practical miners, the most advantageous. In many cases the two can be combined with most beneficial results. H YDKA ULIC MINING. 2 3 In deciding which plan to adopt the miner will do well to bear in mind the principle that he is working, as a first consideration, to make money .not only to tear away the largest pos- sible amount of gravel. Consequently, that method or combination of methods is the cor rect one which will deliver the largest quantity of gravel (with its gold) at his head box in the shortest time provided always that he has sluice capacity and water sufficient to wash it thoroughly. In nine cases out of ten the method to be adopted is decided by the amount of water available ; and if the supply is unlimited (which is very rarely the case) the hydraulic is always better than the boom, if the two cannot be used. The quantity of work possible to be done with the hydraulic varies, of course, with the nature of the gravel, the size of the stream, and the head. A very sound practical authority gives the following rough estimates : No. 1 nozzle, supplied with 100 miners' inches of water, under a head of 100 feet, assisted by a 24 HYDRAULIC MINING. ground-sluice of 100 inches, will wash 600 cubic yards per day ; 3 men. No. 4 nozzle, supplied with 700 inches, under a head of 150 feet, will wash 3,000 cubic yards per day ; 4 men. CHAPTER IIL DIRECTIONS FOR THE MINER. I ATTEMPT in this work to give rales and di- rections for solving all the simpler engineering problems which the practical hydraulic miner (who in most cases is unacquainted with higher mathematics) will have presented to him. To be successful the miner must make himself thoroughly acquainted with the contents of this chapter, which is intended to be explanatory of such mathematical operations as will be noted. He who is able to add, subtract, multiply, and divide will find nothing in this book beyond his ability, if this chapter is carefully studied, and if the same hard common sense and intel- ligence which in all other matters distinguishes the American miner from. other classes of work- 26 HYDRAULIC MIXING. ingmen is brought to bear on the subject. Hy- draulic mining is a branch of engineering, and because its operations can be guided wholly by mathematical rules it presents so much of cer- tainty and so little of risk. Consequently, the miner who desires to improve nis property and increase his profits, but is unable from various causes to obtain the assistance of an experi- enced engineer, will certainly find it to be worth his while to gain the power of solving, alone and unaided, a majority of the problems which will be presented for consideration in the ordinary course of his business. I will call the reader's attention, therefore, to the following subjects : 1. The use of decimals ; 2. The method of transforming fractions into decimals ; and, , 3. The principle of expressing the terms of a problem in a uniform and correct manner. DECIMALS. The decimal system is a method of numerical expression based upon a division of the unit HYDRAULIC MINING. 2/ one (1) by ten (10) or multiples of ten (as, 100, 1,000, 10,000). For example, instead of say- ing one-half () say five-tenths ( T 5 ), and instead of saying one-quarter (J) say twenty-five one- hundredths (-$/V). The system, however, does not stop here, but includes a system of nota- tion which does away completely with the form of the fraction thus : -f- is written .5 TTT .25 fVo " .84 TO " -012 yVoV w -611 Toifoo " .00014 Hence, to write down a decimal fraction deci- mally, follow this rule : 1. Eeplace the figure 1, which is always the first figure of the lower part of the fraction, by a dot ( . ). 2. Rub out as many of the last figures of the lower part of the fraction as there are 28 HYDRAULIC MINING. figures in the upper part, and place these figures in the room of the figures rubbed out. For instance, to express decimally the frac- tion four hundred and eleven ten-millionths Replacing the 1 by a dot, we have .0000000. Second, as there are three figures in the upper part of the fraction, we rub out the last three ciphers of the above, and replace them with 411, making .0000411 Again, express decimally three hundred Jind one thousandths (yVoV)' Replacing the 1 by a clot gives .000 and placing in the 301 gives .301 Again, express thirty-two tenths (ff). This fraction is evidently the same as three and two- tenths (Sy 2 ^), which, treated by the rule, gives 3.2. The addition of decimals is performed exactly as any other addition. Place the two or more quantities under each other, taking care that the decimal-points, the dots ( . ), are in a line, and place the decimal-point in the answer or result in the same position, thus: H YDRA I LIC MINING. 2Q .0104 3.26 .192 114. 117.4624 In subtracting adopt precisely the same course, thus: 1.242 .012 1.230 ,61306 .4 .21306 In multiplying place the quantities in the or- dinary way, multiply as usual, and point off as many figures in the result as there are decimals in the two quantities multiplied, thus: 1.264 .06 .07584 .SO HYDRAULIC MINING, Agai n : .1103 .17014 4412 1103 7721 1103 .018766442 The division of decimals is performed as fol- lows: Set down the figures as in the ordinary style of long division. Annex to the dividend (the quantity to be divided) first as many ciphers as may be necessary to make the number of deci- mal figures in the dividend equal in number to those in the divisor, and, second, as many more as may be necessary to obtain a figure large enough to divide. Divide as in the ordinary method. Point oft' in the result as many places for de- cimals as the number of decimals in the dividend exceeds those in the divisor. HYDRA ULIC MINING. 3 1 NOTE. If the divisor or dividend consists of decimals commencing with a cipher or several ciphers (as, .0218 or .00014), these ciphers may be wholly disregarded in the operation of division. The following examples cover all cases : (a) When the divisor is larger than the divi- dend as, to divide 1.265 into .04: 1.265).04000000(3162 3795 2050 1265 7850 7590 2600 2530 In this case, there being 8 decimals in the di- vidend and 3 in the divisor, the difference 5 will be the correct number for the quotient or an- swer, which, instead of being 3162, will be .03162. 32 HYDRAULIC MINING. (b) When the divisor is less than the dividend as, to divide .142 into 4.6: .142)4.600(32 426 340 284 There being an equal number of decimals in both divisor and dividend in this case, the quo- tient remains unaltered as 32. But if, instead of annexing two ciphers, we had annexed, say, six, the quotient would have been 323943, we would have had four more decimals in die dividend than in the divisor, hence the result would have been 32.3943. In the division of decimals, ciphers may be an- nexed to any extent desirable until no remainder occurs; this makes the division perfect. Other- wise it is an approximation. But in all calcula- tions except those of a most delicate nature it is sufficiently accurate to annex only enough ci- phers to produce three decimal figures in the result. H YDRA ULIC MINING. 3 3 (c) \Vhere ciphers are prefixed to dividend or divisor, or both, a study of the following opera- tion will explain the method. Thus, to divide .0014 into .0000403 : .0014). 0000403 (28 28 123 112 There being 7 decimals in the dividend and 4 in the divisor, the answer should contain the difference, or 3 figures, giving, in place of 28, the quantity .028. TRANSFORMATION OF FRACTIONS INTO DECIMALS. When a problem under consideration contains fractions it is always necessary to reduce these to decimals. This is done by simply dividing the numerator of the fraction (the top figure) by the denominator (the bottom figure). Thus, to reduce J to decimals divide 1 by 2 = .5 ; or to reduce -f, divide 3 by 8 = .375 ; or to reduce J, 34 HYDRAULIC MINING. divide 3 by 4=.75. The division need not be carried to more than three figures. This must be done in all cases. As an exam- ple, if the grade of a flume is found by experi- ment to be 3^ inches per box, the fraction is to be reduced to decimals by dividing 5 by 12, thus : 12)5.000(416 48 20 12 80 72 Pointing off the result (416) according to the rule of division of decimals, the grade is found to be 3.416 inches per box. THE PRINCIPLE OF EXPRESSING THE TERMS OF A PROBLEM UNIFORMLY. At the beginning of a problem it is necessary to reduce all the elements to the right shape and form. If this is done confusion will be avoided. HYDRAULIC MINING. 3.5 If it is not done the results will be false almost invariably. Hence, Express perimeter, lengths of flumes, ditches, piping, head, diameters, etc., in linear feet and decimals of a foot. Express areas (such as sections of flumes and piping, and mouths of nozzles) in square feet and decimals of a foot. Express discharge in cubic feet per second. Express velocity in linear feet per second. Express grade in decimals of a foot per linear foot. Thus, discharge from a flume or pipe, which is frequently given in miners' inches, should be reduced to cubic feet (see Miner's Inch) ; grade, which is generally expressed in inches per box (12 feet) or inches per rod (16 feet), must inva- riably be altered to feet per foot ; as, for in- stance, a grade of 1 inch per box equals 1 inch per 12 feet, or -fa of an inch per 1 foot. But 1 1 2 - of an inch equals y^ of a foot, which, reduced to decimals, equals .007 of a foot nearly. The correct mode of expression, therefore, will be .007 feet ner foot. 36 HYDRAULIC MINING. Velocity must be expressed in feet per second, and perimeters in decimals of a foot. A flume having a perimeter of 20 inches measures If of a foot. Reducing this to decimals, we have, in place of 20 inches, 1.666 feet. DEFINITIONS. The subjoined definitions and explanations will be found necessary to a perfect understand- ing of the technical phrases used in succeeding pages. The reader is therefore invited to im- press on his mind the exact meaning and value of each term defined : Mass. The quantity of matter which a body contains irrespective of whether that quantity be diffused through a large space, through the influence, for example, of heat (as in the case of steam) ; or compressed into a small space, through the influence, for example, of cold (as in the case of ice) is called its mass. Volume. The amount of space occupied by a body is denominated its volume. Weight. When a body is freely acted upon by gravity, but is prevented from moving by some HYDRAULIC MINING. 37 supporting obstacle, the pressure on the point of support is termed its weight. Jet. A jet is the mass of water escaping from a vessel through an orifice in its side or bottom, which orifice, of course, must be below the level of the water. Flow. The volume of water which escapes from a vessel through an orifice (which may be wholly or partly under the water) in any given time is its flow for that time. Velocity. The distance passed over by any given mass of water in any given time is called its velocity. The direction of the motion is immaterial. Head. The vertical distance between the level of standing water in -i reservoir, and the centre of the orifice from which it flows into the air, is called its head. Wet Perimeter. If a flume or ditch is 20 inches wide, 6 inches deep, and full of water, its wet perimeter is 20+ 6+6=32 inches. If of the same dimensions, but only containing 3 inches of water, the wet perimeter is 20+3 -j-3=26 inches. The same flume again, if 38 H YDRA ULJC MINING. empty, has no wet perimeter at all. In other words, the wet perimeter of a water- channel is the length of so miicli of its base and sides as is wetted by the water. This measurement deter- mines friction. Friction. When one body slides upon an- other, the inequalities and roughnesses of the two surfaces interlock and cause a resistance, which is termed friction. If, now, the sliding body has not sufficient weight and cohesion to create abrasion or wear among these irregulari- ties and roughnesses, the degree of friction which arises bears a well-known proportion to the weight of the sliding body. This is the case when water slides along the floor of a flume or ditch, and the proportion of friction developed to the weight of the water is called THE CO-EFFICIENT OF FRICTION. This co-efficient, of course, varies as the water is muddy or clear, or as the flume floor is rough or smooth. It is however, wholly independent of the areas of the surfaces in contact. In other words, two flumes of different size, if made of HYDRAULIC MINING. 39 the same quality of lumber and carrying similar water, will develop identical co- efficients of fric- tion the proportion of friction to the moving weights will be the same. But the weights of water in each being different, the amount of fric- tion developed in the larger flume will be greater than in the smaller. Momentum. The quantity of force which a body in motion is capable of exerting when stopped suddenly is called its momentum. Proba- bly the best illustration of this is the power ex- hibited by a jet of water when it strikes a bank of gravel. It may be measured by multiplying the weight of the striking body by the velocity ' at which it moves. For example: A nozzle de- livering a stream of water 3 inches in diameter, with a velocity of 150 feet per second, will hurl against a bank every second a force equal to the weight of a column of water 3 inches in diame- ter and 150 feet high, multiplied by 150, or 3-H tons nearly. But it is to be remembered that this is the amount of force developed at the mouth of the nozzle only. Immediately on passing into the air the stream of water, acted 4O HYDRAULIC MINING. upon by the force of gravity and the resistance of the air, and further weakened through its own disintegration, becomes less powerful. At a suf- ficiently great distance from the mouth of the nozzle the velocity will be wholly lost, and no force or power remains except that due to the weight of each particle of water under the influ- ence of gravity. Again, it is not to be thought that if a gravel-bank is struck with the force above mentioned 34 tons of earth must be moved per second. This statement appears to be unnecessary, though it may be logically de- duced from the first, unless it be remembered that vast quantities of force must be expended in destroying the cohesion of the gravel and overcoming its inertia. Once in a state of mo- tion, the force transmitted from the nozzle to the gravel would, if the force could be applied .at a point which would equally affect the whole, give it as rapid motion as the water, less fric- tion. But this can never be accomplished in practice. MENSURATION. A few questions in mensuration will arise in HYDRAULIC MINING. 41 working the problems presented in the following pages. These are as follows : 1. To find the Area of a Circle. Multiply the diameter (in inches) by the decimal 3.14 and the product by one-quarter of the diameter. The result will be the area in square inches. Divide this by 144, and the result will be the area in square feet. EXAMPLE. What is the area of a circle 18 inches in diameter ? 16 multiplied by 3.14=50.24 multiplied by 4 (which is one-quarter of the diameter) =201. 06 square inches, which divided by 144= 1.32 square feet. 2. To find the Area of a Section of a Flume with Straight Sides. Multiply the width of bottom (in inches) by the height of sides (in inches); the, product will be the area in square inches, which, divided by 144, gives the area in square feet. EXAMPLE. What is the area of a section of a flume 20 inches wide and 15 inches high ? 20 multiplied by 15=300, which divided by 144=2.08 square feet. 42 ff\ DRA UIJC MINING. 3. To find the Area of the Section of a Ditch with Sloping Sides. Add together the width at top and bottom (in inches), multiply this sum by the depth (in inches), and divide the result by 2. The quotient, divided by 144, will be the area in square feet. EXAMPLE. What is the area of the cross-sec- tion of a ditch 60 inches wide at the top, 36 inches at the bottom, and 12 inches deep ? 60 plus 36 = 96, which multiplied by 12-1152, and this divided by 2=576 square inches, which divided by 144=4 square feet. 4. To find the Area of the Cross -Section of a Ditch whose Sides slope to a Point at the Bot- tom. Multiply the width (in inches) by half the depth (in inches), and divide the product by 144. The result is the area in square feet. EXAMPLE. What is the area of a pointed ditch 60 inches wide and 18 inches deep in the centre ? 60 multiplied by 9 (half the depth) = 540 square inches, which divided by 144=3.75 square feet. CHAPTER IV. THE PROPERTIES OF WATER. IN hydraulic mining the properties of water are to be considered in but two conditions: (a) When at rest as in the case of dams, re- taining walls, and pressure-boxes ; and (if)) When in motion as in ditches and flumes, WATER AT REST. The three principles here laid down will be worth consideration by the miner who desires to work understandingly. 1. Water at Rest transmits Pressure equally in all Directions. If a pressure of 100 Ibs. is exerted on the entire surface of the water in a reservoir whose section is 10 square feet, this pressure is transmitted in its entirety not only to the base, but to every 10 square feet of its sides. Thus, if the interior surface of the reser- 44 HYDRAULIC MINING. voir (base and sides) measures 250 square feet, and a pressure of 100 Ibs. is placed on the water- surface (of 10 square feet), the base and walls will receive a total pressure of 2,500 Ibs. Or if the box be so closed at the top as to leave but one square foot of water exposed, and if a pres- sure of 100 Ibs. be applied on this one square foot, an equal pressure will be transmitted to every square foot of interior surface, and the total will consequently be 25,000 Ibs. Or, to illustrate this remarkable property still more thoroughly, suppose the top of the vessel to be covered with the exception of one square inch. If on this a pressure of 100 Ibs. is placed, every square inch of interior surface will be pressed outward with this weight, which, for the size box under consideration, would amount alto- gether to 1,800 tons. This is the principle utilized in the hydraulic press. 2. The Pressure exerted by Water on the Horizontal Bottom of a Vessel is wholly inde- pendent of the shape of the vessel^ and is equal to the weight of a column of water whose base is H } DRA ULIC MINING. 4$ the area of the horizontal bottom, and whose height is equal to the depth of the liquid. 3. The Pressure of Water on the sides of a Vessel is equal to the weight of a column of water whose base is equal to the area of the side, and whose height is equal to one-half the depth of the liquid. Owing to this law the pressure on the walls and base of a cubical vessel is equal to three times the weight of the water contained. The two principal problems in hydraulic min- ing arising under the head of water at rest are those connected with the construction of dams and reservoirs and water-boxes. Keferring to the third principle just enun- ciated, it will be seen that the pressure on any surface under water depends upon two things the depth of water and the area of the surface pressed. For example, what will be the pres- sure against the inner slope of a dam 50 feet long, 12 feet wide, and 12 feet deep at the bot- tom? Multiply the area of the slope (50x12= 600) by the average vertical depth in feet of the centre of gravity of the slope (6) =3, 600, and 46 HYDRAULIC MINING. multiply this by 62.5 (the weight of a cubic foot of water) =225,000 Ibs. It will be noted that the pressure is not a pound greater if the water reaches back from the face of the dam for miles, than if it were a reser- voir only a few feet broad. Hence, if a reservoir is built simply for storage, make it large and shallow rather than small of area and deep. The loss by solar evaporation will, it is true, be much grenter, but this disadvantage will be counterbalanced, first, by the small leakage ; second, by the cheapness of the dam ; and, third, by the great safety of the construction. A miner cannot go to his work under more de- pressing circumstances than with the thought that at the head of the gulch in which he is im- prisoned is a dam whose embankment of 15 or 20 feet in height may at any time give way and destroy not only himself and comrades, but every trace of improvements that have been the labor of years. Probably the best and safest embankment, where there is no carpentry or masonry, is that one which is modelled on the plan of the beaver- HYDRAULIC MINING. 47 dam. This is a familiar sight in the West, and its details can be easily studied. The beaver- dam is seldom if ever "known to give way, and this quality of stability is what is of all things most desirable. The water or pressure box has three uses. It determines permanent and steady head ; it offers an opportunity to clear the water from gravel and other debris before passing it into the pipe, and it should be the means of freeing it from a large portion of the air which it absorbs while travelling at a high velocity. Construction. The pre.?sure-box should be a deep vessel, with a pyramidal bottom pointing downward and provided with a trap. This, on being opened from time to time, will clear out gravel and sand which has collected in the bot- tom, and which, if allowed to accumulate, would in time rise to the level of the outflow. The pressure-box is best built when its height, ex- clusive of pyramidal bottom, is three times its greatest width. The section should be longer one way than another. It should have a lip overflow on one of the short sides, and the water 48 HYDRAULIC MINING. should enter the box at the centre of its top, and from the same side as the discharging-lip. All screening should be done in the flume. A partition reaching down below the outflow, and parallel with the longest sides, is highly recom- mended by good authorities. The discharge- hole should be two-thirds of the distance from top to bottom (no increase of power is gained by placing it at the bottom), and should be in one of the long sides. If these directions are ob- served a large quantity of the gravel unavoidably carried into the box will be prevented from pass- ing into the pipe, much of the air will also be kept out, and a steady and even head will be se- cured. We have now to consider only the strength of the box. That this is an important point may be judged by the fact that if its height is 12 feet, and its section 3 by 4 feet, it will have to sustain a pressure of not less than 35 tons. MEASURING THE WATER OF STREAMS. If the channel of the stream has a moderately even outline, measure its depth at regular in- HYDRA ULIC MINING 49 tervals from shore to shore. Add all these depths together, and divide the sum by the number of soundings. An average depth is thus gained. Calculate then the area of the section according to Rule 2, page 41. Measure the velo- city by means of a float, and make the test about half-way between the bank and the centre. Mul- tiply the area by the velocity, and the product will be the flow. Of course the test for velocity should be made at the same point where the measurements for depth are made, and a place on the stream should be selected for both where the banks are as nearly parallel as may be, ana where the current and flow is the most tranquil. EXAMPLE. A stream is 24 feet broad, and ten soundings at every two feet on a line from bank to bank give 2, 6, 8, 9, 7, 11, 11, 10, 9, and 2 inches as the depths. The average velocity as determined by float is 4 feet per second. What is the flow ? The sum of the 10 soundings is 75 inches, which gives an average depth of 7.5 inches, equal to .625 of a foot. The area of the section then is 24 multiplied by .625 = 15 square feet. 5O HYDRAULIC MINING. The velocity being 4 feet per second, the flow is equal to 15 multiplied by 4=60 cubic feet per second. If the stream runs over a bottom so irregular tli at an average depth cannot be gained or an average velocity measured, there is no recourse but to construct an artificial channel having no grade, into which it may be turned while mea- sures are made. The same rule applies in this case as before, and it should be understood' that in both the results are very rough approxima- tions. To reduce the result to miners' inches refer to the table of equalities, page 18. CHAPTER V. CONSTRUCTION OF WATER-WAYS. WHEIST the miner has measured the stream from which he is to draw his water-supply, and has determined that point where he will tap it, he is prepared to consider the question of water- channels. These may be of three kinds the ditch, the wooden flume, and the iron pipe. The ditch is the most indestructible, the cheapest, and the easiest to repair. Instead of deteriorat- ing, it improves in condition year by year if carefully built. On the other hand, more water is lost by evaporation, and in stormy seasons it is subject to injury by overflows, land-slides, caves, etc., etc. The wooden flume eliminates the ele- ment of loss by leakage, but not by evaporation. It occupies the middle ground in point of cost, but requires much watching. It is, moreover, the most easily destroyed by fire and flood. The iron pipe prevents all loss on the way, is most 52 HYDRAULIC MINING. easily cared for, and costs the most. It is seldom considered to be the best method of water trans- portation, except when a necessity, as in the case of siphon-bends or very steep grades, or on the rocky side of mountains where ditching would be costly. It is generally desirable to have the least pos- sible fall in a water channel, or, in other words, to bring the water to as high a point of the ground to be worked as circumstances will allow. As the friction of the sides and bottom of a channel retards the flow, and necessitates a high- er grade than would be necessary if there were none, it becomes of importance to decrease this element as much as possible. On this score wood and iron water-ways present decided ad- vantages, owing to their comparative smooth- ness. In any case, however, the quantity of friction developed depends upon the wet perime- ter of the channel used. The following law will therefore be found of service : TJie least wet perimeter that will hold or carry a given volume is attained when the width of bot- tom is from If to 2% times the depth of the side*. HYDRAULIC MINING. 53 For example, a channel having a cross- section of 510 square inches will develop the least amount of friction when its dimensions are 15 by 34, or 17 by 30, or somewhere between these measure- ments. A knowledge of this fact will be found ser- viceable in constructing flumes. The least peri- meter, of course, requires the least lumber, and many thousand or million feet may be saved in a long flume by building in the correct pro- portion. When the head of the flume is above timber- line, or in high altitudes where ice forms early in the fall, it is an advantage in many respects to have it so narrow in width that an ice-crust can easily form itself from bank to bank. If this is secured water will often flow a month or six weeks longer than otherwise. The reasons are obvious. In making the preliminary survey of a placer- claim a sound authority advises as follows : First, lay off the dump ; second, decide how much grade and fall to give the sluices ; and, third, find the least fall necessary between source of 54 HYDRAULIC MINING. water and water-box. The remaining distance will then be the greatest head attainable. The suggestion is pertinent, because it brings to mind the fact that a good dump and an abundant grade for sluices are fully as necessary for econo- mical gravel-washing as a heavy head of water. When the linear distance be; ween the sources of supply and the water-box is determined, and the least fall that will carry the water ascer- tained (after considering the questions of fric- tion, evaporation, and leakage), the grade per foot is found by dividing the total fall in feet by the total length in feet. Multiplying the result (which will generally be a decimal) by 100 or 1,000 -will give the grade per 100 or 1,000 feet. Having now the grade per foot and the quantity of water to be carried (as determined by gaug- ing the stream or streams tapped by the ditch or flume the proper deductions having been made for leakage and evaporation), the area of cross- section of the water-way may be determined by the rule for the determination of the least wet perimeter, which has just been given. Solar evaporation is very active at high alti- HYDRAULIC MIMXG. 55 tudes. The ordinary figures representing loss through evaporation ( T V to -f^ of an inch of sur- face per day) are much too small for ditches above an altitude of 6,000 feet. Evaporation also proceeds much more rapidly in shallow water than in deep, and when the velocity is high. Experiments made during 1877 on the 12-mile wooden flume of the Fuller Company, on the Swan River, Colorado, indicated a loss of from 10 to 18 per cent, daily. This flume is, how- ever, an extreme case, being about 10,000 feet above sea-level. Probably an inch of surface would be an average loss. , Leakage occurs most extensively in gravelly soils. From 1 to 5 inches of surface per day are extreme losses, with an average, perhaps, of about 2 inches, which it will be always safe to count on, except in old ditches. A high velo- city decreases loss through the soil. Water-channels of uniform section should al- ways have a uniform grade. Otherwise there will be an accumulation in some points and a thin- ning-out in others, with deposits of sand and silt in the latter case, and in each case with in- 56 HYDRAULIC MINING. creased danger of breakage. It will also be found highly advantageous in earth ditches to have a complete system of waste-weirs to carry off surplus waters occasioned by floods and to lessen the damage of breaks. These should be put in just below wherever a new stream falls into the diich, and just above those places where, by rea- son of a shelly or crumbly soil, the ditcli is weak. A break is bad, not only because it must be re- paired, but because while being mended all min- ing operations must cease. In the spring, difficulty is often encountered in starting the water through the heavy accumu- lation of snow in the ditch, which, if it be long, can be flushed out only with great trouble 1 . This operation will be materially hastened if the ditch is cleaned out in short sections of a mile or two each. Cut a hole in the bank a mile from the head, and when the water has soaked that far it will carry off the unmelted snow through this break with great rapidity. As soon as clear the hole is mended and another made a mile further on. Time will be saved by thus taking the ditch in sections. H YDRA ULIC MINING. 5 7 Cost. When the plough and scraper can be used ditching can be done at 20 cents per cubic yard. If the soil is so rocky as to call for the pick and shovel, it will cost from 30 to 40 cents. A safe figure to be taken for the construction of a ditch 3 feet wide at bottom, 4|- feet wide at top, and 18 inches deep is $1.25 per rod. It can be done for less. The larger the ditch the less costly it will be in proportion. CHAPTER VI. FLO W OF WATER IN FLUMES AND DITCHES. THE following rules for the solution of prob- lems concerning the flow of water in ditches and iiumes are commended to the miner, only with the proviso that the directions laid down in Chapter V he strictly complied with. Before doing any figuring let every element of the prob- lem, as grade, area of section, velocity, wet peri- meter, discharge, and length, be reduced from the ordinary measurements usually given to those laid down in the "Directions." If this is done the results may be depended upon ; other- wise they will be of no value. It is to be remembered, however, that these rules do not take into account leakage and evaporation two elements of loss which have been spoken of already. It will be impracticable in this manual to enter into the details of these elements of loss, as the subjects are too intri- 58 HYDRAULIC MINING. 59 cate ; and, in addition, it would be unnecessary, inasmuch as the records of experience are more satisfactory and nearer the truth. 1. What grade per foot must be given to a flume or ditch of uniform section to enable it to discharge a given quantity of water in a given time? RULE 1. Divide the number of cubic feet of discharge required by the area in square feet of the section of the flume. This result is the velocity necessary, expressed in feet per second. Multiply this result by itself. Multiply this product by the wet perimeter, expressed in feet, and multiply this product by the decimal .0001114. Divide this product by the area of the section of flume, expressed in square feet. Call the re- sult A. Multiply the velocity in feet per second by the wet perimeter, expressed in feet, and multiply this product by the decimal .00002426. Divide this product by the area of the. section of the flume, expressed in square feet. Call the quotient B. 6O HYDKA ULIC MINING. Add together A and B. The result is the grade per foot (expressed in decimals of a foot) which must be given to the flume to make it carry the required water. EXAMPLE. What grade per foot of length must be given to a 20-inch flume whose sides are 12 inches high, in order that it may deliver 28 cubic feet of water per second steadily ? Wet perimeter, say 42 inches = 3.5 feet. Area of section, 240 sq. inches^ 1.66 sq. " Discharge, =28.00 cubic " Then, dividing the discharge (28) by the area of section (1.66), we have 16.86 as the velocity in feet per second. Following the rule, the velocity (16.86) multi- plied by itself equals 284.25 ; multiplying this by wet perimeter (3.5) produces 994.87 ; multi- plying again by the decimal .0001114 produces .1108 ; dividing this by urea of section (1.66) gives .0667. Call this A. Multiplying the ve- locity (16.86) by wet perimeter (3.5), and the product by .00002426, produces .0014315, which divided by the area of the section of the flume (1.66) =.00086. Call this B. Adding A (.0667) HYDRAULIC MINING. 6 1 to B (.00086), we have as a final result .06756, which is the grade per foot (expressed in deci- mals of a foot). If we multiply this result (.06756) by 1,000, we have the grade per thou- sand feet, which will be 67.5 feet (near enough). To reduce this result to the ordinary terms viz., inches per box of 12 feet divide first 1,000 by 12, which produces 83.33 (which of course represents the number of 12-foot boxes in a 1,000-foot flume). Then, the grade being 67.5 feet in 83.33 boxes, for each box it would be the result of d viding 67.5 by 83.33, which is .79, or the grade would be .70 of a foot per box of 12 feet. Finally, there being 12 inclu ^ in a foot, we multiply .79 by 12 and obtain 9.48 inches per box, or nearly 9^ inches. 2. What is the average velocity and discharge secured in a flume or ditch of uniform cross- section and grade ? KULE 2.- Multiply area of cross-section in square feet by the grade in feet per foot, and the product by 9,000. Divide this result by the wet perimeter in feet. 62 HYDRAULIC MIMXG. Extract the square root of the quotient. (See table at end of book. ) From the result subtract .1089. The result equals the mean velocity of the water (expressed in feet per second). Multiply the area of cross-section by the mean velocity. The result equals the discharge (expressed in cubic feet per second). EXAMPLE. What is the discharge attained in a 30-inch flume with 12-inch sides, having a uniform grade of f -* )Tr (.01) of a foot for every foot of length ? Multiplying the area of cross-section (2.5 square feet) by the grade (.01) produces .025 ; multiplying this by 9,000 yields 225 ; dividing this by the wet perimeter (4.5) gives 50, whose square root is 7.0711; subtracting from this the decimal .1089, we have 6.9622, which is the mean velocity (expressed in feet per second). This calculation is in reality accurate only for a flume. In a ditch, where friction is greater, it will be necessary to subtract about 10 per cent, (or .6962) from the result found, leaving 6.266 HYDRAULIC MINING. 63 as the correct figure. Then continuing, multi- ply the mean velocity (6.9622) by the area of cross-section (2.5) ; we have 17.40, which is the discharge (expressed in cubic feet per second). 3. What must be the section of a ditch or Hume of uniform grade which will discharge a given quantity of water in a given time ? There is no simple rule that will solve this problem, and an answer must be sought experi- mentally upon the following plan : RULE 3. Assume a convenient section, and, the grade being known, calculate its discharge ac- cording to Rule 2, page 61. If this discharge is greater or less than the required one try again with a smaller or larger section until the correct one is found. Cost. With lumber at $12 to $15 per thou- sand, delivered at the head of the flume, so that it can be floated down, a flume 2 feet wide and 2J feet high can be finished at a cost of $3.85 per box (of 12 feet in length) ; and one 6 feet wide and 3-J- feet high at $8.50 per box. CHAPTER VII. IRON PIPING. THE problems which arise in operating iron pipes are the following : 1. What is the velocity attained in a cylindri- cal iron pipe, laid straight or with easy curves, its head, length, and diameter being known? BULE 1. Multiply the diameter in feet by the head in feet. Call this product A. Add together the total length of pipe in feet, and .54 times its diameter in feet. Call this sum B. Divide A by B. Extract the square root of the quotient (see table at end of book) ; multiply this root by 48. The product will be the velocity in feet per second. EXAMPLE. What velocity will be attained in a pipe 12,600 feet long, 6 inches (.5 of a foot) in diameter, and having a head of 200 feet ? // } DRA ULIC MINING. 65 Multiply diameter (.5) by head (200) =100; call this product A. Add to the total length (12,600 ft.) 54 times its diameter: .5 multiplied by 54 equals 27=12,627. Call this sum B. Di- vide A (100) by B (12,627) =.0079. Extract the square root of this resul f , which = .0889. Mul- tiply this root by 48=4.26, which is the velocity per second, in feet. 2. How many cubic feet of water per second will be discharged from a cylindrical iron pipe, straight or with easy curves, its head, length, and diameter being known ? RULE 2. Ascertain the velocity by preceding rule. Then multiply the velocity thus attained by the area in square feet of a section of the pipe. The result will be the discharge per sec- ond, in cubic feet. 3. What head of water is necessary for a cylindrical iron pipe, straight or with easy curves, its diameter and length being known, to produce a given discharge per second ? RULE 3. Multiply the required discharge (expressed in cubic feet) by itself. Call this A. 66 HYDRAULIC MINING. To tne total length of pipe add 54 times its diameter. Call this B. Multiply A by B. Call the product C. Divide the diameter (expressed in feet) by .235. Multiply this product by itself continuously four times. Divide C by this product. The quotient will be the head in feet. EXAMPLE. What head is necessary to pro- duce a discharge of 12 cubic feet per second at the end of a pipe 8 inches (.666 feet) in diame- ter and 350 feet long, the pipe being straight or with easy curves ? Multiply the discharge (12) by itself = 144; call this A. To the total length (350) add 54 times its diameter (36) =386 ; call this B. Multiply A (144) by B (386) =55,584 (C). Di- vide the diameter (.666) by .235 = 2.834. Mul- tiply this product (2.834) by itself continuously four times =182.801. Divide C (55,584) by this product (182.801) = 3.04 feet nearly, which is the required head. 4, Wliat diameter of pipe is necessary to carry H YDRA ULIC MINING. 67 a given quantity of water per second, its length and total head being known ? RULE 4. Multiply the head in feet by 5,280, and divide the product by the length in feet. Call this A. Multiply the discharge in cubic feet per sec- ond by itself, and multiply this product by 5,280. Call this B. Divide B by A. Extract the fifth root of the result (see tables at close of book). Multiply this by the decimal .235. The product is the diameter (in feet). EXAMPLE. What must be the diameter of a pipe 6,000 ft. long, with a head of 400 feet, which will discharge G cubic feet of water per second ? Multiply the head (400) by 5,280=2,112,000, and divide this product by the length (6,000) = 352 (A). Multiply the discharge (6) by itself =36, nd multiply this product by 5,280=190,080 (B). Divide B (190,080) by A (352) =540. Extract fifth root of this quotient (540) =3.52. 68 HYDRAULIC MINING. Multiply this root (3.52) by .235 .8272, which is the required diameter (expressed in decimals of a foot). Curves. Curves and bends in pipes always cause some loss of power. They also furnish a place for the accumulation of air and sediment, as well as weaken the tube. They are, how- ever, unavoidable in practice, and the rules by which to calculate the additional amount of head necessary to counteract their influence, or the amount of power lost, are perhaps too com- plex for the aim of this work. An angular bend in a pipe should be avoided, if at all possible. In most placer districts there are workers of sheet-metal of sufficient ability to produce cir- cular elbows. The latter should be made with a radius never less than five times the length of their diameter. To ascertain this curve mea- sure the diameter of the pipe, and cut a string that will be just five times this length. Then if one end of the string be held fast the other will describe the correct curve. A still larger radius is better when possible. In fact, the gentler the curve the better. HYDRA UL1C MINING. 69 Care should be taken to back up piping very solidly at each change of direction. The neces- sity of this precaution will be self-evident. Cases have occurred where whole sections of piping poorly backed have been torn to pieces as soon as the head was put on. The cost of piping, finished and set up, may be approximated as follows : Cost at manufactory 4^c. per Ib. Freight, 1,500 miles 3^c. Making into pipe 3c. " Grading, laying, ballasting, and fas- tening ,c. " 12c. per Ib. The hydraulic grade-line is an imaginary straight line, extending from a point on the side of the water-box or reservoir, denominated the velocity-head, to the mouth of the nozzle. If the pipe be constructed exactly on this line, the water flowing through it, no matter what its velocity or volume, will exert no bursting pres- sure. In other words, the grade of the hydraulic grade line is such that the velocity caused by the grade is exactly sufficient to carry down all that 70 HYDRAULIC MINING. 'the pipe will hold, and there is no outward pres- sure exerted except that on the bottom of the pipe due to the water's weight. If, however, there he a change in the diameter of the pipe at any point this equilibrium ceases to exist. It is never possible in practice to adopt this line as a course, but generally close approximations can be made to it. As will be shown further on, it is highly advantageous to do this wherever possible. To find the Hydraulic Grade-Line. RULE 1. Calculate the velocity in pipe due to the total head. (See Rule 1, page 64.) Look in Table 3, and find the head correspond- ing to this velocity. Lay off this head on the side of the reservoir from the surface of the water. Its termina- tion will mark the line of the velocity-head. From this point sight to the nozzle of the pipe ; the line of sight is the hydraulic grade-line. In constructing a line of piping three cases may arise by reason of the inequalities of the ground to be passed over : 1. The pipe may lie below the hydraulic grade- line. // 1 'DRA I 'LIC MIKING. 7 I 3. T,he pipe may lie above the hydraulic grade- line. 3. The pipe may lie both above and below. CASE 1. Pipe below Hydraulic Grade- Line. There is here a bursting pressure, varying in amount according to its distance below the line. To find this pressure at any point, ascertain the distance of that point vertically below the hy- draulic grade-line. Call this measurement the bursting-head as, for example, A, E, Fig. 1, which assume to be 6 feet. The pressure, then, on each square inch of pipe at that point is equal to the weight of a column of water whose base measures 1 square inch and whose height is 6 feet. Thus, 1 square inch multiplied by 6 feet (72 inches) =72 cubic inches =.04166 cubic feet multiplied by 62.5 (wt. of cubic foot of water) =2. 6 Ibs., which is the pressure per square inch. Consequently, if the pipe lies con- siderably below the hydraulic grade-line, it will need to be of thicker iron than the rest. This law applies in crossing deep hollows. CASE 2. Pipe above the Hydraulic Line. There is now a decided loss of head, and conse- 72 H\DRAULIC MINING. quently of power, in portions of the pipe, if it be of the same diameter throughout. Find now that point in the pipe which is highest above the -hydraulic grade-line (H), and from that point draw Uo new grade lines, one to the pressure -box (H V) and one to the nozzle (H N). Along the former calculate the bursting pressure as above, measuring the different heads from the new line (as F E). Along the latter there will be no bursting pressure, for the grade of the nozzle end of the pipe will be so much greater than that of the reservoir end that it will carry off the water very much faster, and will, in fact, act like a gutter, and be partially empty. The remedy for this is to put in pipes having a decreased diameter. To calculate the requisite diameter, assume that the pipe ended at that point where it is highest above the hydraulic grade-line (H). Calculate the discharge in cubic feet at that point according to Rule 2, page (55. This will give the amount of water in cubic feet per second which the nozzle section (H N) must carry. The head will be the vertical distance from H to N. Then, by Rule 4, under the head H YDRA UL1C MINING. J 3 of Iron Piping, the requisite diameter may be calculated. CASE 3. Pipe both above and below the Hy- draulic Grade- Line. The problem now becomes more complicated. Divide the pipe into sections for every passage it makes above the hydraulic grade-line, and make the divisions at the several points (A, H, and I) where the pipe attains its highest posi- tion. Calculate (Rule 2, page 61) the discharge at the end of each section. The first section will have a head equal to the vertical distance between its discharge and the velocity-head in the pressure-box. All succeeding heads will be measured from the level of the discharge just below them to their own discharge. For ex- ample, the head at A is the vertical distance between A and the water-level in the reservoir, less the velocity-head. At H the head is the ver- tical distance between H and A. At I it is the distance between I and H, etc. These measure- ments will furnish a series of heads and grades from which the diameters of pipe necessary may be calculated according to Rule 4, p. 66. 74 HYDRA ULIC MINING. If it be desired to calculate bursting pressure in Case 3, measure the heads of different points from the ne \v hydraulic grade-lines, and proceed as directed in Case 1. In building and laying lines of iron piping, whether to conduct water from one reservoir to another or from the water-box to the pit, money will be saved by paying close attention to this subject. It will easily be seen that if the pipes are larger than is necessary, iron, which is gene- rally costly in mining communities, will be un- necessarily used, while at the same time the pipes will become filled with air, and much of the force thereby lost. Again, if the pipes are too small, the danger from bursting is greatly augmented. The pipe, after being laid, should be carefully anchored at many points, and, when possible, protected from the weather. The three conditions arising under unequal and varying grades are shown by the following figures : HYDRA ULIC MINING 7 5 Fig. 1. Pipe below Hydraulic Grade- Line. Fig.1. W.- Water-box. F. E. N. Line of Pipe. V. A. N. Hydraulic Grade-Line. A. E. Bursting-head. Fig. 2. Pipe above Hydraulic Grade- Line. Fig. 2. W. Water-box. E. H. N. Piping. V. N.-Hydraulic Grade-Line. F. E. Bursting-head. V. H. and H. N. Supplementary Hy- draulic Grade-Lines. Fig. 3. Pipe above and beloiv Hydraulic Grade" Line. Fig.3. W.-Water-box. A. E H. F. I. N.-Piping. V. N.-Hydraulic Grade-Line. V A, A H, H I. I N Supplementary Hydraulic Grade-Lines. 7 6 HYDRA ULIC MINING. Sheet iron, from which the piping is made, is manufactured of various thicknesses. The stan- dard of measurement is the inch, and a size known, for example, as No. 16 is approximately ^ of an inch in thickness. The following table will give the strength of sheet-iron piping, and will be found of service. STRENGTH OF IROtf PIPING. This table gives the thickness In Inches and decimals of an Inch which Iron piping must have to stand a given pressure. Heud of Water, in feet. I - 150 200 250 300 : 400 500 600 800 1,000 (; Resulting Pressure against Sides of Pipe, i:i Its. per sq ^ inch. | ' 48 - 4 65.1 87 | 109 130 174 217 260 347 434 Q ] Required I hick ness of Pipe, in in ches or decimci Is of an inch. 2 j .009 .013 .018 .022 .027 .036 ! .045 .055 .075 .095 8 .013 .020 026 .033 .040 .054 ! .068 .082 .112 .143 4 .017 .026 .035 .045 .053 .072 .090 .110 , .149 .191 5 ; .022 .033 .044 .056 .067 .090 , .113 .137 .186 .237 6 .026 .040 .053 .067 .080 .'08 .136 .165 .224 .287 7 .030 .046 .062 .078 .093 .126 j .159 .193 .261 .333 8 ! .034 .053 .071 .089 .107 .144 .181 .220 .298 .382 9 .039 .059 .079 .101 .120 .163 j .205 .247 .335 .427 10 .044 .1166 .089 .112 .134 .181 .227 .275 .373 .475 12 i .053 .080 .106 .134 .161 .217 i 573 .330 .448 .575 14 .061 .093 .124 .156 .187 .253 i .318 .387 .523 .666 16 j .069 .106 .142 .178 .214 .288 .363 .440 i .596 .763 18 \ .078 .120 .159 .201 .242 .326 1 .409 .495 .670 .850 20 ! .088 .132 .177 .223 .267 .361 ; .454 .549 .746 .950 24 .105 .159 .2i3 .268 .321 .433 i .545 .660 .895 l.iro 30 .132 .198 .267 .336 .402 .543 .681 .825 1.120 1.4J) 36 .156 .238 .318 .402 .483 .651 , .8 9 .990 ! 1-340 1710 42 i .184 .279 .372 .469 .562 .759 .955 1.160 j 1.570 2.000 48 ; .210 .317 .425 .535 .641 .866 1.090 1320 1.790 2.290 HYDRAULIC MINING. fj For example : What thickness of iron should be used to make a 20-inch pipe which must bear 200 feet head of water ? The figure given in the table is .17? inch, which, by the follow- ing table, corresponds to between No. 5 and No. 6 iron. Or, the head being 100 feet and the pipe 10 inches in diameter, the thickness will be .044 inches, which corresponds nearly to No. 17. In selecting the iron it will always be safer to take the size one larger than that called for by the figures. Table showing the thickness, in decimals of an inch, of the different sizes of sheet-iron from No. 4 up to No. 30 : No. 4 has a thickness of .204 of an inch. ;< 5 " " .181 " " 6 " " " .162 " 9 u 114 10 u " " .101 11 " <( " .090 12 " " ' .080 13 " " l< .071 14 " " .064 15 '' " " .057 16 " ' .050 HYDRA ULIC MINING. No. 17 has a thickness of .045 of an inch. 18 " .040 " 19 " .035 " 20 " " .031 " 21 " .028 " 22 " .025 " 23 " .022 " 25 u .020 " ' < 017 26 " .015 " 27 " .014 " 28 " .012 " 29 " .011 " 30 " .010 " It must be remembered that tlicse figures ap- ply only in cases where the end of the pipe is closed and no discharge occurs, or where the discharge is on the same level as the inflow. Of course if the pipe is discharging at one end the pressure is relieved, and the pipe is called upon to sustain only that bursting pressure due to its depression below the hydraulic grade-line. As in practice the depression of the pipe leading from the water-box to the pit is rarely more than 5 to 20 feet below the hydraulic grade-line, the iron will be compelled to resist a pressure never over 10 Ibs. to the square inch. This, ordinary stove-pipe iron would generally do. CHAPTER VIII. NOZZLES AND DISCHARGE. THEORETICALLY, the quantity of water dis- charged from the nozzle of a pipe may be de- termined by the following rule: KULE 1. Extract the square root of the head, and multiply this root by 8.03. The product will be the velocity in feet per second with which the water escapes from the mouth-piece. Multiply the area of the mouth-piece (see- page 41) by this velocity, and the result will be the discharge in cubic feet per second. EXAMPLE. What quantity of water will be discharged from a pipe, under a head of 100 feet, through a 3-inch nozzle ? The square-root of the head (100) is 10, which, multiplied by 8.03, gives 80.3 feet as tin- velocity per second. The diameter of nozzle 8O H YDRA ULIC Mh\ ING. being 3 inches (.25 of a foot), its area would be .25 multiplied by 3.14 multiplied by .0625 = .04906 square feet, which, multiplied by the ve- locity 80.3, equals 3.93 cubic feet, which is the discharge per second. The actual discharge is probably about 80 per cent, of the theoretical one in well-made nozzles, provided with inside flanges to prevent revolu- tion of the stream, and in this case would be 3.14 cubic feet per second. This, reduced to miners' measure (see page 18), would represent about 115 inches. The power of the stream thrown by a nozzle has been dis cussed under the head of Momentum (page 39), and nothing remains to be said on the subject, except that every precaution should be taken to prevent the stream from issuing in a ragged con dition. Its effectiveness depends very largely upon its smooth and cylindrical form. If this is secured it will travel through the air for a much longer distance without disintegration than otherwise. The mouth-piece, therefore, should be very smooth, and the arrangements of the pressure or water box so perfect as to H YDRA ULIC MINING. 8 1 exclude all sand and gravel, and, if possible, all air. Fine specks of quartz passing through the mouth-piece will not onlv cut the metal, but will spoil the shape oi tne jet. CHAPTER XX. THE SLUICE. UPON the construction and operation of these channels almost everything in placer-mining de- pends. It is a comparatively simple matter to disintegrate the most cohesive gravel-bank and deliver it at the head -box, but by no means so easy to so conduct the washing as to save even a respectable amount of gold. In former days miners were content with saving from 30 to 50 per cent., for the ground worked at those times was rich enough to pay handsomely even then. The miner of to-day, however, has to deal with a lower grade of material worth from 15 to 25 cents to the cubic yard, and must work closer to produce a profit. In California ground worth only 4 cents to the cubic yard is worked suc- cessfully. In Colorado and Montana there is no need as yet (and in fact there is none in Cali- fornia) to touch such poor gravel, for there are HYDRAULIC MINING. 83 millions of acres still unopened which will pro- duce 20 to 30 cents. This circumstance, how- ever, affords no legitimate excuse for careless working. It will be found at the present day to be just as expensive to save 50 as 90 per cent, in mines where there is any pretence to careful work. And the sooner the business of gravel- washing is reduced to a science, the sooner it will attract the attention of investors and re- ceive the benefit of their assistance. Steadiness of flow in a sluice is of great im- portance. The quantity of water passing, and its velocity, must be uniform to secure the de- position of a maximum of gold. Again, it is no economy to crowd a flume with dirt beyond cer- tain limits, which will be noted further on. If the gravel is caved in too large quantities it will be found economical to erect other sluices. It is to be remembered, also, that water always tra- vels faster in the centre of the channel, and is also higher in level. Consequently the bulk of the gravel and boulders will travel down the middle of the flume. Dimensions The maximum quantity of wa- 84 HYDRAULIC MINING. ter which may be advantageously used in a sin- gle sluice of correct dimensions when the ground is ordinarily full of boulders, is set down by good practical authorities at 1,000 miners' inches. This corresponds to a discharge of 95,000 cubic feet per hour, which, with gravel and boulders, would represent about double that amount of moving substance in the sluice. When more than this is used the current will be so strong that men cannot work to any advantage in the head-box. Sluices intended to clear off top dirt must be short and large. In this case the top dirt is presumed to be nearly free of gold and of boulders. The test of friction is perhaps the correct one on which to base calculations for the correct di- mensions. The general behavior of this force is referred to on page 38, and on page 52 will be found the law of the least wet perimeter. In a sluice, the object being to move all the gravel from the head-box to the dump by means of the forces of water and gravity, it is important that the least amount of the former should be lost in overcoming extraneous resistance. We may in- HYDRAULIC MINING. 85 crease the work of the water by giving it veloci- ty through the instrumentality of heavy grade, but if the flume is of incorrect dimensions there is always a loss for which the miner receives no compensation, and which may be avoided. To secure this point let the miner first decide upon the largest sized boulder which he will allow to go through his flume. Tf it be 2 feet in diameter, then it is clear that his flume must carry at least 2 feet in depth of water. We have then a figure for a side measurement. Ac- cording to the law on page 52 the bottom should be from If to 2| times the height of the side, or, taking the side at 30 inches, the bottom should be 52J to 67J inches wide. If, however, the ground is free from large boulders, and it be merely necessary to ascertain the dimensions best adapled to carry the greatest economical quantity of water (1,000 inches), Eules 2 and 3, on pages 41 and 42, will furnish the correct area of section. 1,000 inches is equal to 27.1 cubic feet per second. Double this discharge to make room for the gravel. The flume must then dis- charge 54.2 cubic feet of material per second. 86 HYDRAULIC MINING. Having ascertained the area of section in square feet, we may resolve it into correct dimensions by the following rules : RULE 1. The width to be 2J times the sides. Multiply the area in square inches by 4, and divide the product by 9. Extract the square root of the quotient. The result will be the height of side in inches. RULE 2. The width to be 1J times the sides. Multipl} the area in square inches by 4, and divide the product by 7. Extract the square root of the quotient. The result will be the height of side in inches. Those who have a preference for shallow boxes will adopt Rule 1, and those who incline towards deep ones will take Rule 2. Grade. Grade creates velocity. Velocity in- creases the work of water, and consequently where the quantity, of water is small it must be assisted by giving it a greater velocity. As practi- cally the whole question of power with water in sluices depends upon the velocity with which it moves, the question of grade is of great impor- tance. The miner, however, does 'not merely HYDRAULIC MINING. 8/ seek for power in his sluice. While there are boulders and gravel to wash away there is gold to be saved. Consequently, that velocity is the best which will wash away a maximum quantity of gravel and rock and a minimum of gold. Let the miner, therefore, study for a while the com- position of his banks. If the boulders are rounded and well worn they will roll down the sluice with ease under a small head, but if flat they will need more power. And the same is true if they be angular, though not to so great an extent. Scale and leaf gold will float a long distance in a turbid and rapid stream. Generally the physical quality of gold may be determined by an examination of the gravel. The miner should not trust to that caught in his riffles, for much may be washed away which he can never examine. If the gravel and boulders are angular and large the gold will have the same characteristics ; but if the former are pol- ished the gold is round or leafy, and much will be a fine dust. The moving power of water in sluiceways may 88 HYDRAULIC MINING. be approximately judged by the following table : 16 feet per minute begins to wear away fine clay. 30 " just lifts fine sand. 39 " ' lifts sand as coarse as linseed. 45 " ' moves find gravel. 120 " ' " inch pebbles. - .J 200 t( ' " pebbles as large as eggs. 320 " ' " boulders 3 to 4 inches thick. 400 " ' " 6 to 8 600 " " " 12 to 18 We have, then, the following rule for the es- tablishment of grades in sluices when the veloc- ity needed is decided upon : RULE 3. Multiply the velocity expressed in feet per secomi by itself, and the product by the wet perimeter in feet. Divide this result by twice the area in square feet. The result is the total fall in feet per mile. EXAMPLE. What grade must be given to a sluice 12 inches broad and 6 inches deep, that it may carry a velocity of 320 feet per minute, or 5.3 feet per second ? Multiplying the velocity (5.3) by itself, and HYDRAULIC MINING. 89 the product by the wet perimeter (24 inches =2 feet), we have 56.18. This, divided by the area (72 square inches =.5 of a foot), and doubled =56.18, which is the fall in feet per mile. To reduce grades expressed in feet per mile to inches per box of 12 feet, multiply by the decimal .027. Thus, a grade of 56.18 feet per mile equals a grade of 1.5, or 1, inches per box. To reduce to inches per rod (16 feet), multiply by the decimal .036. Prof. Silliman's calculations on California cement gravel, after being disintegrated by blasting, indicate that 1?-|- cubic yards of wa- ter, equal to nearly 15 tons, are necessary to wash 1 cubic yard of gravel. For ordinary gravel, after being caved, probably 8 to 12 tons would suffice. When the course of the sluice is curved the outer edge must be raised, to prevent unequal wear and an accumulation of material. This is much more imperative in the sluice' than in the flume. Riffles. It is not possible within the limits of this work to discuss the subject of riffles QO HYDRAULIC MINING. thoroughly. Nor is it yet decided which of the systems (wood, boulder, or railroad iron) presents the most advantages in the majority of cases. The first is the most extensively used, and will probably always hold its place. Some experiments made in California witli railroad iron demonstrate that that style of riffle was strongly to be recommended for very rocky ground at least. The great efficacy of boulder riffles is well known, and is thorough- ly illustrated in the ground-sluice. As already stated, the bulk of gravel and boulders travels down the centre of a sluice, where there is at once the most water and the greatest velocity. Consequently, it will be found advantageous to have the riffles higher in the centre than in the sides. This will cause a distribution of deposit over the en- tire width of box, and will also prevent the formation of a channel of depression in the bottom of the sluice. The cost of wooden block-riffles, cut from peeled round lumber and squared, will average about $50 per 1,000. A thousand of these HYDRAULIC MIXIXG. gi blocks averaging about 8 inches diameter will cover 80 square yards of bottom. Laying and fastening, and all other expenses concurrent with arranging the bottom of the sluice for work, will bring the total cost to 75 cents per square yard. It will be impossible to quote the expense of rail- road-iron riffles. Old irons are, of course, just as good as new. The cost will be mainly that of transportation. 9 2 H YDRA ULIC MINING. TABLE I. TABLE OF SQUARE KOOTS. The following table of the square roots of numbers from 1 to 200, in elusive, will probably answer all requirements of problems proposed in the preceding examples. If the iigure whose root is to be extracted is not found in the table, take the root of the figure nearest to it. For example, if it is necessary to extract the root of 132.6, take the root of 133. .Yb.i Root. No. Root, 11.8823 11.8743 11.9164 11.9583 183 12. 184 12.0416 II 185 12.0830 12.1244 12.1655 I2.30M 12.2474 HYDRAULIC MINING. 93 TABLE II. FIFTH BOOTS. The following table of numbers and roots will cover all problems that come to the miner. The numbers are printed in heavy type and the roots in light. If the exact number is not found, take the roots of the number nearest to it : No. Root. No. Root. No. Root. 7.59 1.5 5032.84 5.5 59049. 9. 32. 2. 7776. 6. I 77378. 9.5 97.65 2.5 11603. 6.5 100000. 10. 243. 3. 16807. 7. 136638. 10.5 525.21 3.5 28730. 7.5 161051. 11. 1024. 4. 32768. 8. 201035. 11.5 1845.28 4.5 44370. 8.5 248832, 12. 3125. 5. 94 7/i 'DRA UL1C MINING . TABLE III. VELOCITIES AND DISCHAKGES. Head in feet per 100 feet. 1 fc Ci 1 DixfJairqe in cu. j ft. per 24 hours. .0019 .0038 .1 .2 .208 .293 .1633 .2301 14,114 19.880 .0057 .3 .359 .2819 24,360 .0076 .4 .415 .3267 28,229 .095 .5 .464 .3638 31,435 .0114 .6 .508 .3989 34,464 .0132 .7 .549 .4311 37,427 .0151 .8 .585 .4602 39,760 .0170 .9 .623 .4901 42,343 .0189 1.1 .656 .5144 44,431 .0237 1.25 .735 .5753 49,701 .0284 1.50 .805 .6322 54,604 .0331 1.75 .871 .6832 59,011 .0379 2. .928 .7276 62,870 .0426 2.25 984 .7696 66,484 .0473 2.50 1.040 .8168 ! 7U,'572 .0521 2.75 1.080 ! .8482 73,284 .0568 3.00 1.130 .8914 76,982 ;0758 4. 1.310 1.028 88,862 .0947 5. 1.47 1.150 99,403 .1136 6. 1 61 1.264 109,209 .1325 7 1.74 1.366 1 18,022 .1514 8. 1.86 1.455 125,740 .1703 9. 1.96 1.539 132,969 .1894 10. 2.08 1.633 141,145 .2273 ! 12. 2.27 1.782 153,964 .2J52 14. 2.45 1.924 166,283 .3030 16. 2.62 2.057 177,724 .3409 18. 2.78 2.183 188,611 .3788 20. 2.93 2.301 198,806 .4735 25. 3.28 2.573 222,150 .5682 30. 3.59 2.819 243,604 .6629 35. 3.88 3.047 268,960 .7576 40. 4.15 3.21)7 282,288 .8523 45. 440 3.451 298,209 .9470 50. 4.64 3.638 314,352 95 TABLE III. Continued. VELOCITIES AND DISCHARGES. Head in feet per 100 feet. jjj i 1 ! 2 ^ ^ a. Discharge in cu. ft. per 24 hours. |& pi I" 1 1.1360 60. 5.08 3.989 344,649 1.3260 70. 5.49 4.311 372,470 1.5150 80. 5.85 4.602 397,613 1.7040 90. 6.23 4.900 423,435 1.8940 100. 6.56 5.144 444,312 2.0830 110. 6.87 5.395 466,138 2.2720 120. 7.18 5.639 487,209 2.4620 130. 7.47 5.866 506,822 2.8410 150. 8.05 6.322 546.048 3.0300 160. 8.30 6.534 564,576 3.2190 170. 8.55 6.715 580,176 3.4080 180. 8.80 6.903 596,418 3.5960 190. 9.04 7.100 613,440 3.7880 200. 9.28 7.276 628,704 4.2610 225. 9.84 7.696 664,848 4.7350 250. 10.40 8168 705,728 5.2080 275. 10.8 8.482 732,844 5.6820 300. 11.3 8.914 769,824 6.6290 350. 12.3 9.621 831,168 7.5760 400. 13.1 10.280 888,624 8.5320 450. 13.9 10.910 943,056 9.4700 500. 14.7 11.50 994,032 10.4100 550. 15.4 12.09 1,044,576 11.3600 600. 16.1 12.64 1,092,096 12.3000 650. 16.7 13.11 1,132,704 13.2500 700. 17.4 13.66 1,180,224 14.2000 750. 18. 14.13 1,220,832 15.1500 800. 18.6 14.55 1,257,408 16.0900 850. 19.1 15.00 1,296,000 17.0-100 000. 19.6 15.39 1,329,696 17.99CO 950. 20.3 15.94 1,377,216 18.9400 1000. 20.8 16.33 1,411,456 2;>.700 1290. 22.7 17.82 1,539,648 26.5200 1400. 24.5 19.24 1,062,336 30.3009 1600. 26.2 20.57 1,777,248 37.8700 2000. 29.3 23.01 1,988,064 The Standard Wcrfc dn the Subject. FIFTH EDITION. One Volume, Small Quarto, 31 3 Pages, 72 Illustrations, $5.00. A PRACTICAL TREATISE ON Hydraulic Mining in California, With Description of the Use and Construction of Ditches, Flumes, Wrought-Iron Pipes, and Dams: Flow of Water on Heavy Grades, and its Applicability, under High Pressure, to Mining. BY AUG. J. BOWIE, JR., MINING ENGINEER. CONTENTS. CHAP. I The Records of Gold Washing. II. History and Development of Placer Mining in Cali- fornia. III. General Topography and Geology of California. IV. The Distribution of Gold and Deposits, and the Value of Different Strata. V. Amount of Workable Gravel Remaining in California. VI. The Different Methods of Mining Gold Placers. VII. 1're iminary Investigations. VIII Reservoirs and Dams IX. Measurement of Flowing Water. X. Ditches and Flumes. XI. Pipes and Nozzles. XII. Various Mechanical Appliances. XIII. Blasting Gravel Banks. XIV. Tunnels and Sluices. XV. Tailings and Dump. XVI Washing or Hydraulicing. XVII. Distribution of Gold in SSluices. XVIII. Loss of Gold and Quicksilver. XIX. Duty of the Miner's Inch. XX. Statistics of the Costs of Working, and the Yield of D. VAN HOST RAND COMPANY, Publishers, 23 Murray & 27 Warren Sts., New York. * Copies sent prepaid on receipt of price. Valuable Books for me Miner ant Metalinririst. THE PROSPECTOR'S HAND-BOOK, A GUIDE FOR THE PROSPECTOR AND TRAVELLER IN SEARCH OF METAL-BEARING OR OTHER VALUABLE MINERALS. By J. W. ANDERSON, M. A. [Camb.] Seventh Edition, Revised and Enlarged, 12mo, Cloth, $1.50. METALLURGY OF GOLD, A PRACTICAL TREATISE ON The Metallurgical Treatment of Gold-Bearing Ores INCLUDING THE PROCESSES OF CONCENTRATION AND CHLORINATION, AND THE ASSAYING, MELTING, AND REFINING OF GOLD. By M. EISSLER. Fonrth Edition, Revised and Enlarged to 700 Pages, with 25 Addi- tional Plates, and Working Drawings and Chapters on Recent Milling Operations in the Transvaal. 8vo., Cloth, Price $5.00. 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Third Edition, Revised and Enlarged, with Illustrations. 8vo., Cloth. Price - - $5.00. MINERALOGY, CRYSTALLOGRAPHY AND BLOWPIPE ANALYSIS, FROM A PRACTICAL STANDPOINT By ALFRED J. MOSES, E. M., Ph. D., Adjunct Professor of Mineralogy, Columbia College, School of Mines. New York City, AND CHARLES LATHROP PARSONS, B. S., Professor of General and Analytical Chemistry, New Hampshire College, Dunham, N. H. A Description of all Common or useful Minerals, and Tests necessary for their Identification, the Recognition and Measurement of their Crys- tals, and a Concise Statement of their Uses in the Arts. 8vo., Cloth, 336 Illustrations, Price - - $2.00. PRACTICAL MINING. A FIELD MANUAL FOR MINING ENGINEERS. WITH HINTS FOR INVESTORS IN MINING PROPERTIES. By J. G. MURPHY. 16mo., Morocco Tiick^. - $1.00. A PRACTICAL TREATISE ON HYDRAULIC MINING IN CALIFORNIA, By A. J. BOWIE. Fifth Edition, Small Quarto, Cloth. Illustrated, - $5.00. MANUAL OF HYDRAULIC MINING, For the Use of the Practical Miner. By T. F. VAN WAGENEN. Second Edition. Revised. 18mo , Oloth. - - - $1.00. 8vo, CLOTH, - - - - PRICE, S3.OO. Cyanide Process for the Extraction of Gold AND ITS PRACTICAL APPLICATION ON THE WITSWATERSRAND GOLD FIELDS OF SOUTH AFRICA, By M. EISSLER, Mining Engineer; A. I. M. E. ; Member of the Insti- tute of Mining and Metallurgy, Author of "The Metallurgy of Gold." CONTENTS. CHAPTER I. Erection of a Cyanide Plant; CHAP. II. Extraction by Cyanide; CHAP. III. The Sieniens-Halske Process; CHAP. IV. Particulars of Operations at Various Works; CHAP. V. The Chemistry of the Cyanide Process. Index. LIST OF ILLUSTRATION. 1 Selection of Princess Works. 2 Messrs. Butters & Mein's Automatic Distributor. 4, 5 Portrait of Mr. Chas. Butters. 6 Tailing Wheel, Vanner Room and Cyanide Vats at the Jumpers Mine . 7 Staves Cut to Circle. 8 Construction of Filter Vats. 9 Stone Foundations for Filter Vats. 10-Solution Pipes. 11, 12 Butter's Discharge Lid. la Zinc Precipitation Box. 14 The Worcester- Cyanide Plant. 15 The Worcester Cyanide Plant. 16, 17, 18 Depositing Box. 19 General View of the Simmer & Jack Cyanide Plant. 20 Simmer & Jack Filter Vats. 21, 22 Simmer & Jack Extraction House. 23 Central Works of the Rand Central Ore Reduction Company. A Guide to the Determination of Rocks: Being an Introduction to Lithology. Translated from the French by G. W. Plympton, Pro- fessor of Physical Science at Brook- lyn Polytechnic Institute. By EDWARD JANNETTAZ. 12mo., Cloth, - - $1.50. HAND-BOOK OF MINERALOGY; Determination and Description of Minerals Found in the United States. By PROF. J C. FOYE. (Van Nostrand Science Series, No. 86.) Price - - 50 Cents. MANUAL OF BLOW-PIPE ANALYSIS, QUALITATIVE AND QUANTITATIVE, With a complete System of Determinative Mineralogy. With 69 Wood Cuts and one Lithographic Plate. By H. B. CORNWALL. Fourth Edition, Revised. 8vo, Cloth, $2.50. TABLES Showing Loss of Head Due to Friction of Water in Pipes. By E. B. WESTON. 12mo., Cloth, - - - $1.50. QUARTZ OPERATOR'S HAND-BOOK. By P. M. RANDALL. New Edition, Revised and Enlarged, Fully Illustrated. 12mo., Cloth, - - $2 00. 4.38587 CAtflFdRN UNIVERSITY OF CA^lFbRNIA LIBRARY K A -HJvJ *p.oic Jt> in $ V6 . o 1 . .0 < o C 066