Catol SuuutM STATE OF ILLINOIS STATE GEOLOGICAL SURVEY FRANK W. DbWOLF, Director ULLETIN NO. 29 PURCHASE AND SALE OP Illinois Coal on Specification BY ji S. W. PARR Work in cooperation with Illinois Coal Mining Investigational, and University of Illinois ILLINOIS STATE GEOLOGICAL SURVEY UNIVERSITY OF ILLINOIS URBANA 19 14 ILLINOIS GEOLOGICAE SURVEY LIBRARY MAY 7 195ft » ILLINOIS STATE GEOLOGICAL SURVEY 3 3051 00000 0392 STATE OF ILLINOIS STATE GEOLOGICAL SURVEY FRANK W. DeWOLF, Director Bulletin No. 29 PURCHASE AND SALE OF Illinois Coal on Specification BY S. W. PARR Work in cooperation with Illinois Coal Mining Investigations, and University of Illinois ILLINOIS STATE GEOLOGICAL SURVEY UNIVERSITY OF ILLINOIS URBAN A 19 14 SCHN EPP & Barne ^ State P Rinters Springfield III 1915 STATE GEOLOGICAL COMMISSION. Edward F. Dunne, Chairman Governor of Illinois Thomas C. Chamberlin, Vice -Chair man Edmund J. James, Secretary President of the University of Illinois Frank W. DeWolf, Director Fred H. Kay, Asst. State Gcolociist LETTER OF TRANSMITTAL. State Geological Survey, University of Illinois, October, 15, 1914. Governor E. F. Dunne, Chairman, and Members of the Geological Commission. Gentlemen : I submit herewith a report by Prof. S. W. Parr of the University of Illinois, Consulting Chemist of the Geological Survey, en- titled : "Purchase and sale of Illinois coal on specification," and recommend that it be published as Bulletin No. 29. This subject is one of growing interest to producers, sellers, and users of Illinois coal ; and Professor Parr's work as a pioneer investigator has commanded respect everywhere. The report reviews some of the work published by the Illinois Coal Mining Investigations, Cooperative Agreement, as well as extensive experiences in purchase of coal by the State Board of Administration, to both of which organizations we are greatly indebted. Very respectfully, Frank W. DeWolf, Director Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/purchasesaleofil29parr CONTENTS. PAGE Introduction 9 Increased use of heat-unit basis 9 Opportunity for securing data : 10 Principles of coal sampling 11 Care in sampling 11 A representative sample 11 Material to be taken 11 Amount 11 Ratio of size to mass 12 Mill for crushing 13 Mixing and subdividing 14 Moisture control 16 Conditions that facilitate loss of moisture 16 Precautionary measures 17 Illustrative methods of coal sampling 17 Face sampling 17 Directions for collecting face samples in the mine 17 Sampler's kit 19 Shipment of sample 20 Samples taken from commercial supplies 20 Use of grinder and riffle 20 Sampling car during unloading 24 Sampling car without unloading 25 Composite samples 25 Dust or duff determination 26 Moisture changes 28 Moisture conditions and nomenclature 28 Calculations 28 Commercial valuation as affected by chemical and physical properties 29 Moisture 29 Relation of coal-bed moisture to commercial moisture 29 Loss of moisture on shipping 31 Use of coal-bed moisture content as a basis 34 Range of variation for moisture factors referred to geographical location 35 Ash 35 Causes of variation in ash 35 Controlling the quality of the output 3S Necessity for mine operators to know the ash values of their coal 38 Volatile matter, fixed carbon, and sulphur 39 Duff or dust 40 Calorific value &. 40 Relation between quantity of heat contained and true value 40 Most favorable conditions for determination 40 Unit coal 40 Meaning and application 40 Calculation of commercial values 41 Analytical data 43 Analyses of mine samples 43 Average analyses by mines and by counties 58 Purchase and sale of coal under specification 72 Use of double standard o f reference 72 Bids and awards 7:; Price and payment 7 1 Specific directions for sampling 75 Taking the sample 76 Reducing the sample 7(> Determination of percentage of duff or dust 77 Obtaining a 5-pound sample 77 Compositing of samples 7 S Summary of coal settlements 1913-1914 78 ILLUSTRATIONS. Figure. page. 1. Grinding- surfaces of coal crusher 13 2. Coal grinder of the coffee-mill type .14 3. Riffle : 16 4. Sampler's kit 18 5. Coal grinder showing method for attaching legs 19 6. Container for coal sample 20 7. Equipment for grinding commercial samples 21 8. Closed mechanical mixer 22 9. Side view of mixer 23 10. An automatic riffling device 24 Plate. I. Districts for classification of c oal samples 43 THE PURCHASE AND SALE OF ILLINOIS COAL ON SPECIFICATION. By S. W. Parr INTRODUCTION. Increased Use of the Heat-Unit Basis. Information concerning the composition and properties of Illinois coal is in constant and growing demand. Requests for such information come from many market centers and are by no means confined to the State of Illinois. They represent specifically the needs of the community at large, and are perhaps characterized chiefly by the fact that they indi- cate a marked tendency on the part of users of coal to scrutinize all available data with the ultimate purpose of making their purchases of this commodity on some basis other than that of simple tonnage. The coal operators are not so eager in this movement for the obvious reason that the mining of coal must be paid for by the ton. It does not simplify the lot of the coal producer, therefore, to be obliged to pay for mining the output on a weight basis, and to sell the product on an entirely dif- ferent basis. Here again, it is believed that a fuller knowledge of the facts relating to the composition of Illinois coals will materially reduce the prejudice of the operator and be of assistance in the making of fuel contracts by enabling him to formulate his proposals more intelligently. It is inevitable that large users of coal will insist more and more upon contracting for their fuel supplies on some basis other than that of a set price per ton. In spite of certain objectionable features and some opposition, which is not without cause for its existence, there is evidence of a steady increase in the use of what is generally termed the "heat-unit 6asis" for the purchase of coal. A simple illustration may serve as an explanation of this tendency : Three Illinois state institutions with substantially the same shipping rate received bids on coal supplies from dealers A, B and C, their respective prices being $1.45, $1.72 and $1.13 p ton. Now, as subsequently proved to be the case, A was able to deliver, and did deliver, coal with an ash and moisture content of 21 per cent and a heat-unit value which entitled him to a settlement price under 10 PURCHASE AND SALE OF ILLINOIS COAL. the contract of $1.55 per ton. The deliveries by B, contained an ash and moisture total of 30 per cent and a heat-unit value which resulted in a settlement price of $1.12 per ton. Similarly, C with a total ash and moisture content of 33 per cent was entitled to a settlement price of $0.97. These items are more conveniently shown in tabular form thus: Table 1. — Difference betiveen the estimated and actual value of coal. Bidder Total per cent of non- combustible in coal as delivered Bidding price Settlement price Difference A B C 21 30 33 $1.45 1.72 1.43 $1.55 1.12 0.97 $0.10 0.60 0.46 It is seen from this table that dealers A and C estimated their coals at substantially the same price, say $1.-45 per ton. The intrinsic values, however, which are at least relatively indicated by the settlement price, are shown to have a difference of substantially 60 cents per ton. Sim- ilarly, dealer B, who estimated his coal as worth $1.72 per ton finds its actual value, or at least its settlement value according to the terms of the contract, to be $1.12 or 60 cents less per ton. The table shows also that a dealer may name his price per ton with very little knowledge as to the intrinsic value of the material. There is little if any relation between the price asked and the actual heat value to be delivered. Illustrations of such discrepancies could be multiplied indefinitely. Opportunity for Securing Data. During the year 1912 the Illinois Coal Mining Investigations, Cooperative Agreement, sampled over 100 mines at three or more widely separated working faces. This work has afforded an unusual oppor- tunity for studying sampling and analytical methods and also for making a comparative study of the variables and constants in individual mines or districts. Furthermore, the writer has been in charge of coal inspec- tion and analysis as conducted for several years by the State Board of Administration with a view to business-like purchase of coal for the State Charitable Institutions. Similarly, a great mass of data has come into our possession through the purchase of coal on specification by the University of Illinois for many years. It is the purpose of this report to present such results and data as may have a direct bearing upon the methods of inspection and the purchase and sale of coal by contract. PRINCIPLES OF COAL SAMPLING. 11 PRINCIPLES OF COAL SAMPLING. Care in Sampling. Without question, the critical point in the entire range of coal inspection and analysis is in the sampling. If the sample taken is truly representative of the entire lot, the results, if accurate in themselves, furnish correct information as to the larger mass of which the sample is a part. If, on the other hand, the sample is in error, the results of the analysis though correct in themselves will be in error so far as they relate to the mass under consideration. Throughout the process of sampling two points must be observed with scrupulous care : First — The sample taken must be representative of the whole, that is, the distribution of the various substances which go to make up the original mass must be maintained without any change in the relative amount of the various constituents. Second — The moisture content, which changes readily, must be under exact control so that at any stage the ratio of moisture present to the original moisture of the mass may be definitely known. A Representative Sample. MATERIAL TO BE TAKEN. As stated above, the first essential in a sample is that it shall truly represent the mass of which it is a part. To secure this result a few fundamental conditions must be observed, as follows : The gross sample must be representative of the various kinds of material present. That is to say, a mass of coal conists of fine stuff, lump, bone, slate, pyrites, and other constituents. As a rule the "fines" differ in composition from the lump, hence the sample must have these twc sorts of material in their proper proportion. The same is even more true of slate or pyrites, of which the composition differs so wide- ly from that of the major part of the mass. An undue amount of such material would cause a serious disturbance in the accuracy of the sample. AMOUNT. In procuring a representative sample a large clement of safety resides in the quantity taken. In general, the larger the amount, the more representative it will be. However, conditions differ. It is easier, for example, to procure an even sample from the face of a working- vein or from a carload of screenings than from a carload or other mass of lump or of run-of-mine coal. In the latter cases larger amounts should be taken than in the former. 12 PURCHASE AND SALE OF ILLINOIS COAL. The limits of practicability for the proper handling of the sample must however be considered. In general, the gross sample should weigh approximately from 200 to 600 pounds. Doubtless 200 pounds of screenings, taken with fairly good distribution throughout the unloading of a 40- or 50-ton car, will yield a very true sample. The difficulties increase greatly with the increase of the size of the particles, as in the case of lump or mine-run coal. If mechanical appliances for grinding are available, the larger amount should be taken, but a smaller sample well crushed down before quartering is better than a greater mass quartered down while the particles are still in larger pieces. RATIO OF SIZE TO MASS. Assuming that the sample as taken is made up of the various kinds of material in proper proportion, the next important item is to maintain these variables in their ratios throughout the process of reducing the gross amount to a small working or laboratory sample. To insure this result, there must be maintained a certain ratio of size of the particles to size or weight of the mass. This, as a rule, is based on a formula which provides that the weight of the largest piece of impurity shall have a ratio to the weight of the mass of about 2 : 10,000. For example, a mass weighing 10,000 grams, or about 22 pounds, should contain no particles weighing more than 2 grams. This would mean that the largest particle, as for example, a piece of iron pyrites, must not be over ]/^ inch in its greatest diameter. The final ratio of sizes, however, should be determined by the methods available for grinding. With mechanical appliances for obtain- ing the smaller sizes, a table of ratios ivith greater safety limits can be adopted than is perhaps practicable where the crushing is done by hand. If a power crusher is available, the entire sample should be passed through the mill and reduced to a size which will pass a ^-inch screen. If the crushing must be done by hand, the first reduction in size of the particles should be such that the entire mass will pass through a 1-inch screen. When by quartering, the sample is reduced to 100 pounds, the size of the particles should be further reduced to a size that will pass a ^2-inch screen, and with a 50-pound sample in hand the crushing should be carried to *4-inch mesh. The subdivisions with their respective sizes are shown in tabular form as follows : PRINCIPLES OF COAL SAMPLING. 13 Table 2. — Size of mesh for different subdivisions of sample. Weight of subdivisions of sample Size of mesh to which each subdivision (pounds). should be broken (inches). 500 1 250 % 125 y 2 60 Vi 30 Vs MILL FOR CRUSHING. Illinois coals are easily crushed in mills which are available at little expense. Hence it is entirely reasonable to require that gross samples, when reduced in mass to 50 or 75 pounds, shall be passed through a mill set for grinding to approximately */$ inch. For this work, a mill which Figure 1 — grinding surfaces of coal crusher. is not of the jaw-crusher or roller type is preferred, since these types produce too large a percentage of line material, and the harder pieces of slate, especially those of flaky or plate-like structure, are liable to pass in pieces having inadmissably large dimensions in two directions, even though the adjustment used would seem to be fine enough to prevent the passage of such material. A grinder of the coffee-mill type or one with projecting teeth on the grinding surfaces will be found to produce a more uniform size and the minimum amount of dust. The grinding surfaces of such a machine are shown in figure 1 , and the same type of mill is shown set up in figure 2. 14 PURCHASE AND SALE OF ILLINOIS COAL. MIXING AND SUBDIVIDING. As a further precaution in maintaining a correct distribution of the .various constituents, emphasis is placed upon the necessity of thorough mixing, followed by even selection of the remaining subdivisions. It is true that fine grinding contributes materially to this end but further care is necessary. It is entirely practicable to mix a 50-pound sample, Figure 2. — coal grinder of the coffee-mill type. ground as above described, by rolling in an oilcloth about five feet square. This is accomplished by taking one corner of the cloth and carrying it over the pile towards the diagonally opposite corner so as to cause the mass to roll over upon itself, then reversing the motion and repeating the process with the other two corners. Fifteen or twenty such alternations, depending somewhat upon the size of the sample, should be sufficient to effect an even mixture. Where available, how- ever, especially in commercial sampling, a mixer is to be preferred. Such a device is most conveniently made in the form of a drum having cone-shaped ends capable of being closed air-tight, and mounted so as to revolve endwise. (See figs. 8 and 9). The subdividing of the larger sample, to reduce it to a convenient size for transmission to the laboratory, requires special consideration as having an important bearing on the maintenance of the correct ratio of constituents. This may be best shown by the data given in Table 3. Note in tin's table that series 1 and 2 are 3-pound samples taken by subdividing in the same manner the same gross sample of about 30 METHODS OF SAMPLING. 15 pounds. Each sample was ground to S-mesh and sized. It will be seen that in series 1, duplicates a and b had 16.6 and 13.7 per cent of the 60- mesh size, whereas in series 2 the duplicates a and b had 22.5 and 23.1 per cent respectively. Note further the great increase in ash in the fine size as compared with the ash in the coarse material. For example, Table 3. — Ash variations in different sizes obtained from duplicate 3-pound samples. Series Mesh Dupli- cate halves a Per cent of each size 41.7 48.4 41.7 37.9 16.6 13.7 29.1 25.0 48.4 51.9 CO L , in "dry coal" Ash cor- rected for CO, in "dry coal" a and b compos- ited by calcula- tion U On 20 .40 .37 .85 1.00 1.31 1.38 .53 .46 .94 .98 14.11 14.00 1 2 Through 20 On 60 a b 15.55 15.42 a 16.32 la Through 60 a b 23.89 23.65 b 15.86 Average. .16.09 2, On 20 a b 15.91 15.68 16.23 16.06 2 2 Through 20 On 60 a b a b a 17.90 2 3 Through 60 22.5 23.1 1.32 1.28 24.09 23.98 b 17.80 Average. .17.85 series 1 having an average of 14 per cent of ash in the coarse size has an average of 23.75 per cent in the fine portion. A similar increase in ash is seen in the corresponding sizes in series 2. The ultimate ash average for series 1 is 16.09 per cent and for series 2 it is 17.85 per cent. These values vary consistently with the variation in the percentages of fine material in the respective series. On the other hand, the duplicate halves a and b throughout, because of their uniformity resulting from the sizing process, show results in the several pairs which check very closely. The values as presented in the table, therefore, show clearly that in the process of subdividing the gross sample and in the further reduc- tion of the sample as received at the laboratory, great care must be exercised to see that no part of the manipulation is of such a nature as will promote segregation of the constituents. A riffle constructed according to the pattern shown in figure 3 may be 16 PURCHASE AND SALE OF ILLINOIS COAL. used to advantage after the sample has been reduced by quartering- to about 30 pounds. At this stage the sample is ground to ^-inch size, hence the riffle openings may be y 2 -mo.\\ in width. With this variation in the openings the riffle as shown in figure 3 is substantially the one described in the Bulletin of the Ohio Geological Survey, No. 9, p. 313, 1908. ^r }* f - •■ '"" ' K, , ,,•' . ■ \* ipl'-^B N;\ ' <0 , ~' ::!i %?: : :r Figure 3. — kiffle. Moisture Control. The second essential in taking and preparing a sample relates to the free moisture present, and requires that the changes in moisture content "must be under exact control so that at any stage the ratio of the moisture present to the original moisture of the mass may be definitely known." CONDITIONS THAT FACILITATE THE LOSS OF MOISTURE. In coals of this region especially, where the moisture in the coal as it comes from the mine averages from 10 to 15 per cent the tendency toward moisture changes is very marked. For example, the process of crushing down the larger sizes affords an opportunity for the escape of moisture. Again, if the coal is spread out on the floor of a hot boiler room or left exposed to currents of air for any length of time there will be a serious change in the moisture factor. Another practice sometimes METHODS OF SAMPLING. 17 followed is that of assembling the various increments of the gross sample in a sack or other receptacle permitting a relatively free trans- mission of air. Samples kept in this manner for any length of time or shipped in such containers will have a moisture content quite different from the original. PRECAUTIONARY MEASURES. The methods employed, therefore, in collecting and reducing a gross sample must have special reference to this tendency on the part of the free moisture to escape. The work should be done rapidly in a room at or below the normal temperature and, so far as possible, with the use of closed apparatus which admits of the least possible exchange of the contained air. Precautionary measures of this sort should be made at the very outset. The gross sample, which is made up of small incre- ments collected usually over a considerable length of time, should be enclosed in a tight box or clean garbage can having a tightly fitting cover wmich can be closed and locked against the possibility of change until the time for grinding and reducing. ILLUSTRATIVE METHODS OF COAL SAMPLING. Face Sampling. Since the procedure for obtaining the face samples described in this report serves as a good illustration of methods adapted to meet the principles above enumerated concerning the uniformity of composition and control of moisture, the details of the process for collecting, and subsequent preparation for shipment in the small container are here given in full. The methods thus described are applicable in principle to the collection of any and all samples from whatever source. DIRECTIONS FOR COLLECTING FACE SAMPLES IN THE MINE. 1 Selection of the face Choose three faces in the mine as widely separated as possible in order to give a good aA r erage of the coal for that mine. An attempt should always be made to get faces which have not been exposed more than 48 hours. Preparation of the face : j (a). Fresh faces 1. With a pick remove all loose coal (that which sounds hollow when tapped with the pick) and square up the face. 2. Brush off the loose coal, dust and powder stains from the face for a distance equal to the length of the blanket (5 to 7 feet). (b). Exposed faces For exposed faces the procedure is the same as above, except that before brushing- the face, a strip of the coal one to two inches in 1 Substantially as given in Bureau of Mines Technical Paper No. 1 with the exception of the prepara- tion, grinding 1 , etc., of the sample. 18 PURCHASE AND SALE OF ILLINOIS COAL. thickness and about a foot wide is cut down the full vertical height of the face. This is done to give a comparatively fresh face for the sample. Cutting down the sample 1. Spread the blanket at the base of the clean portion of the iace, taking care that it fits close at the bottom. 2. With a pick cut down a strip of coal six inches wide and two inches deep, the full vertical height of the seam. At least six pounds of coal should be cut down for each foot in thickness. All partings of sulphur, bone or slate over y% inches thick are rejected as these are supposed to be thrown out by the miner. Preparation of the sample 1. The blanket containing the sample as cut down should be spread upon a smooth hard place on the floor and the lumps all cracked Figure 4. — sampler's kit. down with a pick to a size suitable for readily passing- into the grinder. This can be done directly upon the blanket. 2. Pass all of the sample through the grinder. 3. The sample is then riffled down until just enough remains to fill the sample can when the material is well shaken down and the can filled full so as to displace as much air as possible. 4. After filling as indicated under (3) the can is sealed with elec- trician's tape. METHODS OF SAMPLING. 19 sampler's kit. The sampler's kit is shown in figure 4. The outfit together with sample cans and labels make up a total weight of 23 to 25 pounds. Where a portable mill is not available the crushing of the larger lumps must be accomplished by tamping. This is a slow and tedious process. With the mill, the grinding of the average gross sample can Figure 5. — coal grinder showing method for attaching legs. be accomplished in thirty minutes. The mill employed in this work was of cast aluminium except the grinding parts and supports, and weighed complete about 18 pounds. The method of assembling and operating is shown in figures 4 and 5. By the use of this outfit a 5-pound sample in the best possible con- dition as to size, evenness of mixture, and accuracy of moisture content, 20 PURCHASE AND SALE OF ILLINOIS COAL. is obtained. Where power and the mechanical accessories are available the time required for delivering 1 the 5-pound sample may be further reduced by one-half or more. SHIPMENT OF SAMPLE. After thus reducing the sample to about five pounds, it is placed in a can, such as is shown in figure 6, and forwarded to the laboratory. The particular feature of the container is the skirted screw cap, which by use of electrician's tape wound about the base of the cover affords further security in sealing. On the inside it should contain a suitable ticket giving all the necessary data. Figure 6.— container for coal sample. Samples Taken From Commercial Supplies. use of grinder and riffle. It should be a comparatively simple matter at any power plant to duplicate in principle the methods for sampling at the mine, and even to improve the conditions for preserving the moisture values. The first essentia] is a power mill through which the entire gross sample can be quickly run. An illustration of such an equipment is shown in figure 7. METHODS OF SAMPLING. 21 Figure 7. — equipment for grinding commercial samples. 22 PURCHASE AND SALE OF ILLINOIS COAL. In place of the blanket for rolling- the samples, a closed mechanical mixer, such as is shown in figures 1 and 2 is preferred. WAL~ ^'GACIOCT CI 12." PULLEY'' Wall, duack&t- AlXfcS Figure 8. — closed mechanical mixer. METHODS OF SAMPLING. 23 A Delivery 5p°a\ T*-*t3cj ■QiT r "F"ur:e Figure 10. — an automatic riffling device. SAMPLING THE CAR DURING UNLOADING. A car of coal may be sampled to the best advantage in the process of unloading. An occasional half shoveful should be thrown into a proper receptacle (see page 17) so that by the time the car is unloaded approximately 200 pounds, evenly distributed throughout the load will have been taken. This will mean about one-half shovelful for everv METHODS OF SAMPLING. 25 ten full scoops. They are best taken in the process of shoveling from the bottom of the car, since the top coal rolls down and mixes fairly evenly with the bottom. It should be kept in mind that in taking a sample there must be obtained the different sizes of coal, fine and coarse in their proper proportions from the entire cross-section of the mass, and also an even distribution of the same lengthwise of the car. Even greater care must be taken to guard against loss of moisture in the process of collecting and in reducing the gross sample for the reason that as a rule the relative humidity outside of the mine is lower and the tendency of the moisture to leave the coal is correspondingly increased. SAMPLING THE CAR WITHOUT UNLOADING. It has been shown in Table 3, that the finer particles of a coal mass are higher in ash and hence have a greater specific gravity. They are therefore more likely to separate by gravity from the coarser material. On this account, if a car is to be sampled without unloading, it is neces- sary to dig' well toward the bottom in order to obtain a representative sample. Three trenches should be dug crosswise of the load, one near each end and one near the middle of the car. These trenches should go down nearly to the bottom of the mass and each size be taken as nearly as possible in its proper proportion. Lump and run-of-mine lots are much more difficult to sample than screenings, but it should be noted that screenings may vary greatly, for not infrequently a car is partially loaded from one bin and finished from another which may be of a different size and composition. After obtaining the gross sample, the methods to be followed are the same as those already given. COMPOSITE SAMPLES. It is often desirable to composite a number of samples. In this way a single sample may be made to represent a much larger quantity of coal and thus cut down the time and expense involved in procuring the analytical data. In this procedure, however, it must be remembered that even greater care should be exercised in taking the several com- ponent samples. The amount of each sample entering into the com- posite must be in proportion to the mass which it represents, and finally a thorough and positive mixing of the composited mass must be effected before riffling down the same to the usual 5-pound quantity. It is convenient to determine the amount of each sample to be taken by employing an aliquot system of weights. For illustration : Suppose we adopt 1 gram to the 100 pounds as the unit which shall enter into the composite. Then a 100,000-pound car of coal should be represented 26 PURCHASE AND SALE OF ILLINOIS COAL. by 1,000 grams. In compositing, therefore, the entire content of each can will not be taken, but instead an aliquot proportion which will give to each car lot its due amount. It is preferable to use such a factor as shall utilize the major part of the several 5-pound samples. In this way the gross composite from 10 cars would aggregate 20 or 30 pounds in weight. It should be put into the mixer and revolved until a thoroughly homogeneous mass is obtained and then riffled down to a 5-pound sample as already described. For this procedure it is obvious that the necessary data should accompany the various samples. A ticket inserted in the can before sealing should give the data needed. The form shown below will be found suitable. DUST OR DUFF DETERMINATION. Specifications usually prescribe the maximum amount of dust allowed. This is designated as the material which will pass through a screen with ^4 -inch openings. Obviously this item is not taken into account in mine samples, but should be determined in samples taken from commercial supplies. A determination of the percentage of dust is best made on one of the rejected quarters of the first subdivision. For example, a gross sample of 200 pounds is mixed and quartered. One of the quarters is taken and weighed. This is screened by shaking- small portions at a time in a sieve with V^-moh openings, preferably a sieve with circular perforations ^-inch in diameter. The fine material is collected and weighed. These two weights together with the other necessary data as above noted should be entered on a ticket and en- closed in the shipping- can. A suggested form for this information is as follows : Received by Date 191 Car initial and number Weight of car content Weight of quarter for dust determination Weight of dust net Shipping point* Shipper or dealer *Where bill of lading is accessible the place from which shipment is made should be indicated. The assembling of the data thus supplied by the several shipments should be made in tabular form at the laboratory. A sample will illustrate further the method of keeping the record and the use made of the data in compositing the final sample. Label Sample of. METHODS OF SAMPLING. FUEL LABORATORY REPORT. University of Illinois. ...... From 27 User. Lot No. Car Initial Ca^No' ' Source : Mine or operator Weight of Car content Weight of quarter taken for dust determina- tion Weight dust: net Sampled by Date of sampling 1 ?, 3 | 4 5 1 6 7 8 9 10 Size mesh before 1st quartering ....Size mesh for composite. Composited by Date compositing Wt. of composite. Air-dry loss Report of Analysis % Laboratory No. Proximate Analysis "Unit coal" Coal "air dried" Coal "as received" Coal "moisture free" (moisture, ash and sulphur free) N. F. Moisture Volatile matter Fixed carbon Ash .-...;.. Total Sulphur CO, Dust ^Tuf [ dories determ. ) B.t.u. Reported 191. Analyst. 28 PURCHASE AND SALE OF ILLINOIS COAL. Table 4. — Data for compositing 10 samples. Laboratory No. 6280. From — Watertown State Hospital. Weight Source: Date of Weight Weight taken for of quart- er taken Net Lot No. Car initial Car No. Mine or Operator taking sample of car content (pounds) the com- posite (grams) for dust determi- nation (pounds) Weight dust (pounds) 1 M.C.St.L. 384979 A & B 1/22/13 69400 694 50 10 2 do 20313 1/24/13 88100 881 50 10 3 do 12201 1/22/13 56100 561 50 8 4 M. 0. 12935 do 86200 862 50 7 5 C. I. M. 657 do 86700 867 50 8 6 M. C. R, 358482 do 49400 494 50 6 7 do 4288 1/24/13 69100 691 50 8 8 I. C. 14027 1/22/13 87100 871 50 12 9 do 13654 do 87700 877 50 6 10 L. S. 34081 do 84600 846 50 10 Composite Total — 7644. MOISTURE CHANGES. Moisture Conditions and Nomenclature. The topic of moisture control has already been discussed, emphasis having- been laid upon the fact that at any stage of the processes the exact ratio of the moisture present to the moisture of the original mass must be definitely known. This implies that moisture changes do occur. Indeed three moisture conditions exist and, since under each condition all of the accompanying factors are modified to meet the specific change in moisture, a special designation is applied to the coal for each one of these conditions. Coal with all of the normal moisture present is designated as "wet" coal or coal "as received." It relates to the moisture at the time of taking the sample. All of the detail of the processes for collecting and reducing the gross sample up to and including the item of sealing and shipping the 5-pound sample involve the preservation of this initial moisture without loss. The second moisture status is that wherein the "wet" or "as- received" coal lias been dried to a point of substantial equilibrium with the moisture of the air, so that in an atmosphere of average humidity it would take on or lose additional moisture very slowly or not at all. In this condition the coal sample is said to be "air dry." This is the condi- tion to which the chemist must bring the samnle in order that the COMMERCIAL VALUATION. 29 processes of finer grinding and weighing may be carried on without change in the moisture factor. Obviously the amount of moisture lost in passing from the "wet" or "as-received" condition to the "air-dry" condition must be carefully measured. The factor thus determined is designated as the "loss on air drying." By use of it all of the values ob- tained from analysis of the coal in the "air-dry" state may be calculated to the "wet" or "as-received" condition. The third condition recognized is that of "dry" coal. This is some- times designated as the "oven-dry" or "moisture-free" state. All of the values found for the coal in the "air-dry" condition may be transferred by calculation and made to apply to the coal as "oven dry." The neces- sary factor in this case is the loss of moisture obtained from drying the "air-dry" sample at or slightly above steam temperature, as 220°F. for one hour. It is not intended here to give directions for carrying out these processes. The terms employed, however, are of so frequent occurrence, and in many cases enter so vitally into a correct under- standing of the methods upon which certain values are based in the making of estimates and arriving at fuel settlements that at least a brief reference seems desirable. CALCULATIONS. To calculate the percentage values obtained on "air-dry" coal to the "dry-coal" basis, divide each constituent by (1 — w) in which w is the moisture present in the "air-dry" sample. The moisture factor for the "dry" coal is omitted of course, and the sum of the resulting constituents should total 100 per cent. To calculate from the "air-dry" values to the "wet," or "as-received," condition multiply each percentage for the "air-dry" state by (1 — /) in which / is the loss on air drying. The moisture factor thus derived plus the loss on air drying equals the total moisture in the "wet" coal. This and the other factors calculated as described should equal 100 per cent. COMMERCIAL VALUATION AS AFFECTED BY CHEMICAL AND PHYSICAL PROPERTIES. Moisture. relation of coal-bed moisture to commercial moisture. In comparison with Eastern and European coal the coal-bed moisture of coals of the Illinois type is high and requires special con- sideration for a proper understanding of many conditions surrounding the handling of this material. In perhaps the majority of cases coal is purchased on the basis of its weight at the mine. As a rule, the first purchaser, at least, is 30 PURCHASE AND SALE OF ILLINOIS COAL. obliged to make settlement on the basis of what is known as the railroad or mine weights. Accordingly the total moisture as found in the vein sample probably represents as accurately as is possible the moisture condition of the coal as weighed in the loaded cars just before shipment from the mine. The chipping, grinding, and riffling process, it is true exposes the coal for about an hour and subjects it to the possibility ot a slight loss of moisture; so also does the process of breaking out, load- ing, hauling, hoisting, and screening, require a number of hours. These two lots, therefore— the coal-bed sample and the car ready for market — are represented practically by the same moisture factor. This would be a reasonable conclusion on theoretical grounds alone, but it is supported also by experimental results, though more data might be desirable on the point. In the table below are given moisture figures obtained on coal-bed samples taken in the usual manner as described above, and, for com- parison, in the same column are given the moisture amounts for coal from the tipple or chutes as it passed to the railroad cars. These results show a very close agreement in the mine-run and screened-lump samples. The greatest variations would be expected in the screenings where the floor material and other foreign matter enter into the output, but even here the agreement is quite close. Table 5. — Moisture in face samples compared with moisture in shipping samples taken at the mine. Lab. No. County No. oi coal bed Moisture in face samples (per cent) Moisture in commercial samples Screened lump (per cent) Mine run (per cent) Screenings (per cent) 5130 5131 5132 Sangamon. . 6 15.22 13.10 14.43 Av.— 14.25 14.75 14.14 14.44 6016 6017 6018 Macoupin. . 6 14.29 15.51 13.81 Av.— 14.54 13.40 13.39 13.39 13.79 13.79 5517 5518 5515 Madison . . . 6 12.44 12.11 13.88 Av.— 12.81 11.89 11.89 12.41 13.42 12.91 COMMERCIAL VALUATION 31 Table 5. — Moisture in face samples compared with moisture in shipping samples taken at the mine. — Concluded. County No. of coal bed Moisture in face samples (per cent) Moisture in commercial samples Lab. No. Screened lump (per cent) Mine run (per cent) Screenings (per cent) 6023 6026 Madison. . . 6 12.52 12.71 Av.— 12.61 11.99 11.99 10.09 10.09 11.78 11.78 5988 5990 5993 Williamson . 6 9.76 8.28 8.72 Av.— 8.92 7.92 7.40 7.66 8.25 8.25 5984 5991 5983 Williamson . 6 7.86 6.95 8.08 Av.— 7.63 7.17 7.45 7.31 8.73 8.73 LOSS OF MOISTURE ON SHIPPING. In the process of shipping and marketing coals of the Illinois type there is frequently a shrinkage in weight due to the loss of the excess moisture. This may be from 2 to 4 per cent of the gross weight, de- pending upon weather conditions, the length of time in transit, and other factors. This shrinkage in weight, however, is not a real loss, since in- crease of the heat value per pound is almost directly proportional to the loss of moisture. When screenings are subjected to extreme weather conditions, such as heavy rains, snow, or sleet, there may indeed be a gain in weight instead of a loss. Obviously this high moisture is a dis- turbing element, and much more so with coals of this type than with those of the eastern bituminous variety, where the coal-bed moisture does not vary widely from the amount which would be in practical equilibrium with the moisture of the atmosphere. To illustrate the amount of variation in moisture due to weather conditions there is presented below the average of a number of moisture values on shipments received at the University of Illinois steam-heating plant during approximately four years and coming from two distinct fields. It is to be noted that shipment from the Danville district is direct. The distance is about 30 miles, and the time between the break- ing out of the coal at the working face to the delivery and sampling at the power station was not more than two or three days. The distance, from Christian County is approximately three times as great, and shipments con- sume on the average two or three times the length of time in transit. 32 PURCHASE AND SALE OF ILLINOIS COAL. Tabue 6. — Moisture values in commercial samples at point of delivery compared with coal-bed moisture. (All samples made on screenings.) Ta- ble No. County Dates covered by shipments No. cars sam- pled Moisture in car samples (av- erage of per- centages) Moisture i n face samples (per cent) Variation from mine moisture (percent) 1 Christian Sept., Oct., Nov., 1907 17 12.67 15.01 Oct., 1908 —2.34 2 Christian. . . Dec, Jan., Feb., 1907-1908 24 13.67 — 1 34 3 Christian .... March, April, May, 1908 19 13.89 — 1 12 4 Christian June, July, Aug., 1908 9 14.40 — 61 Average 12 months . . 13.58 — 1 43 5 Vermilion . . . Sept., Oct., Nov., 1908 19 13.71 12.89 (Av. of seven 2 ) + .82 6 Vermilion . . . Dec, Jan., Feb., 1908-1909 19 13.26 + .37 7 Vermilion .... March, April, May, 1909 17 13.37 + .48 8 Vermilion . . . June, July, Aug., 1909 6 11.44 — 1.45 9 Vermilion . . . Sept., Oct., Nov., 1909 17 13.32 + .43 Average 15 months . . 13.21 + .32 * Note — There have been taken in the Danville district from the one mine seven face samples as follows: 13.14 Sept., 1908. 12.76 March, 1912. 12.20 12.70 13.53 13.27 12.07 Av. 12.89 COMMERCIAL VALUATION. 33 Table 6. — Moisture values in commercial samples at point of delivery compared with coal-bed moisture — Concluded. (All samples made on screenings.) Ta- ble Mo. County Dates covered by shipments No. cars sam- pled. Moisture in car samples (av- erage of per- centages) Moisture i n face samples (per cent) Variation from mine moisture (percent) 10 Vermilion Dec, Jan., Feb., 1909-1910 28 12.04 — .85 11 Vermilion .... March, April, May, 1910 12 12.24 — .65 12 Vermilion June, July, Aug., 1910 4 12.84 — 05 Average 9 months 12.17 — .72 13 Vermilion Dec, Jan., Feb., 1910-1911 31 12.69 — .20 14 Vermilion March, April, May, 1911 20 12.20 — .69 15 Vermilion June, July, Aug., 1911 4 13.03 + -14 16 Vermilion Sept., Oct., Nov., 1911 23 13.42 + .53 Average 12 months 12.79 — .10 . 17 Vermilion Dec, Jan., Feb., 1911-1912 35 13.24 12.89 Av. of seven + .35 18 Vermilion March, April, May, 1912 18 13.99 +1.10 19 Vermilion June, July, Aug., 1912 9 11.70 —1.19 20 Vermilion Sept., Oct., Nov., 1912 11 13.80 + .91 21 Vermilion December, 1912. . 12.76 — .13 Average 12 months 13.80 + .91 3-4 PURCHASE AND SALE OF ILLINOIS COAL. USE OF THE COAL-BED MOISTURE CONTENT AS A BASIS. From the data presented it seems evident that the controlling factors are weather or season, and distance from the mine to the delivery point. The greater the time between the mining of the coal and its delivery, the greater the variation in moisture from the normal. Furthermore, mine weights are based upon a moisture content which corresponds quite closely to the normal or coal-bed moisture. Although it is true that the moisture content in the mine itself varies to a certain extent at the different working faces, and that there may be further variations due to moisture conditions in the mine and to the extent to which finely divided foreign matter from the floor and roof are allowed to mix with the coal, yet the moisture factor for the regular output of a mine is remarkably uniform. This uniformity in moisture content indicates the practicability of adopting the normal or coal-bed moisture factor of a given mine as the moisture percentage present in the coal weighed at the mine, on the as- sumption, of course, that conditions of mining are those which ordinarily attend the handling of coal in Illinois. Indeed, when one examines the variations due to shipping under all sorts of weather conditions, it is seen at once that where settlement is based upon mine weights this method is entirely practicable, and indeed is probably subject to smaller factors of error than the usual sampling methods as carried out at the point of delivery. Under the system of sampling the coal at the point of delivery loss of moisture is disregarded. The coal is brought to the "air-dry" condi- tion, and the moisture determined on the laboratory sample in the usual manner. The values thus obtained on the "air-dry" sample are calculated to the "dry-coal" basis by dividing each percentage by 1.00 minus the "air-dry" moisture. To derive the values on the wet or mine weight basis, the values for the "dry" basis are multiplied by 1.00 minus the total moisture as established for the coal-bed or normal moisture. The same result in slightly different form may be calculated directly from the "air-dry" to the "wet" coal by multiplying the values obtained from the "air-dry" sample by a factor derived from the expression : \—W -w in which W is the total per cent of water assumed to be present in the "wet" coal and w is the per cent of water in the "air-dry" sample. Of course, if the factor thus derived is applied to the moisture con- tent of the air-dry sample, the resulting value represents the equivalent COMMERCIAL VALUATION. 35 percentage of that moisture when referred to the "wet" basis. The total moisture of the "wet" coal, therefore, minus the percentage of moisture in the "air-dry" coal gives the moisture loss which would have occurred if a mine sample of the coal had been brought to the same "air-dry" condition and the loss on such air drying obtained by direct weighing. In such a case, however, where a total moisture factor at the mine is recognized, there is no need of determining what would have been the loss on air drying. RANGE OF VARIATION FOR MOISTURE FACTORS REFERRED TO GEOGRAPHICAL LOCATION. A study of the tabulated results of coal analysis (Table 9) shows that a certain limited range of variation exists in the vein moisture over certain fairly well defined areas. For example, north and west from Williamson and Jackson Counties the percentage of vein moisture is greatest and averages from 12 to 15 per cent. In that part of coal No. 6 southeast of the Duquoin anticline, the percentage of coal-bed mois- ture drops appreciably to an average of 7 to 10 per cent, whereas in Saline County a still lower figure is reached for coal No. 5. Ash. causes of variation in ash. The ash in the commercial output of Illinois coals is subject to even greater variations than is the moisture, and, although it is not possible to arrive at so definite a factor for the product of a given mine as can be done for moisture, there is all the more need for acquainting ourselves with certain definite and well-established facts. A few of these facts may be emphasized as follows : ist. The ash content obtained from selected-lump or hand- picked samples does not necessarily bear any relation to the ash of the average output of the mine. 2d. The ash values obtained for coal-bed samples represent approximately the normal ash of the seam. It is most nearly dupli- cated in the commercial output of the mine by the ash content of the screened lump. 3d. The greatest divergence in ash percentages is found in the fine stuff or screenings which often contain double, and some- times even more than double, the ash of the coal-bed sample. The results seldom fall below V/z times the normal ash of the bed. In Table 7 ash values are given for a number of mines in each of which face samples were collected at widely separated points. The variations in the ash content of these samples do not exceed 3.5 per cent 36 PURCHASE AND SALE OF ILLINOIS COAL. in any one mine. This extreme variation probably is due not so much to a variation in the coal as to the impracticability of excluding- from each sample exactly the same proportion of the parting, slate, etc. How- ever, the average of the three face samples doubtless constitutes a fair average of the normal or coal-bed ash for any given mine. Table 7. — Ash in face samples compared with ash in commercial shipping samples taken at the mine. O O Ash in face samples "dry coal" Ash in Commercial samples "Dry coal" County Screened lump Washed nut Nut 3-inch Mine run Screen- ings A— Chris- tian 6 7.57 9.44 6.84 10.71 9.82 9.45 Av.— 8.97 19.13 « 19.13 B — Madison 6 11.71 14.00 12.53 Av.— 12.75 13.12 13.12 14.95 16.23 15.59 25.82 25.82 C — Madison 6 14.15 12.43 12.02 Av.— 12.87 15.15 15.15 25 72 25.72 -rrr. D — Sanga- mon 6 10.84 12.42 12.10 Av.— 11.79 14.71 15.60 15.15 E — Sanga- mon 6 11.57 12.14 14.13 Av.— 12.61 14.21 14.81 14.52 17.96 17 96 F — Sanga- mon 5 14.73 13.09 11.48 11.91 Av.— 12.80 17.87 17.87 17 13 17 13 COMMERCIAL VALUATION 37 Table 7. — Ash in face samples compared with ash in commercial shipping samples taken at the mine. — Concluded. CD o O Ash in face samples "dry coal" Ash in Commercial samples "Dry coal" County Screened lump Washed nut Nut 3-inch Mine run Screen- ings G — Sanga- mon 5 9.94 10.01 Av.— 9.98 Av. 83 samples 16.02 H — Verm il- 6 11.95 Av.— 11.95 13.71 13.71 15.35 15 35 l—William- son 6 9.39 10.48 8.20 Av.— 9.36 14.06 13.81 13.93 15 36 15.36 J— William- 6 12.46 12.01 12.48 Av.— 12.33 17.05 16.43 16.74 17.72 17.72 K— Wil- 6 10.65 Av.— 10.65 13.98 13.98 14.13 14.13 With this value as a basis it is of interest to note that the com- mercial output will most nearly approach this factor for ash in the screened lump. Probably the next closest .agreement is found in the washed nut, the next in the mine-run, and the greatest divergence is naturally in the screenings. The regular mining processes account for these conditions. The floor underneath the coal bed is composed of earthy matter. With the present-day methods of mining, blasting, and basis of settlement, there is a constant tendency to include this earthy material along with the coal, and since it is in a finely divided form it is not readily seen. In shoveling from the floor, therefore, especially at the clean-up of a room, more or less of this earth or shaly matter goes out as coal. It is obvious, therefore, that the finer material will always be higher in ash, and any other grade will be modified in proportion to the amount of fine stuff present. 38 PURCHASE AND SALE OF ILLINOIS COAL. CONTROLLING THE QUALITY OF THE OUTPUT. It is evident from the foregoing that an improvement in quality is possible by exercising care in the various processes of mining and preparation of the output. For example, by careful screening, washing, picking, and other processes, the ash content may be lowered materially, even below the normal factor, just as an increase of dust, dirt, and earthy matter will augment the ash factor. Although it is known that mining methods, such as excessive blasts, basis of settlement, and other factors, directly encourage the mining of this refuse and inert material, it seems evident that the average operator is not aware of the extent to which his output is thus contaminated. Some misapprehension is evident also with regard to other grades than screenings. Washing of coal, for example, if carefully done, may and should reduce the ash content from these abnormally high figures down to and even below the normal coal-bed ash, but too rapid work or other careless conditions may leave the coal with practically the same ash after passing through the washer as upon entering it. More- over, the finer the size, the greater the possibility of ash reduction by washing, but there is also greater possibility, and in too many cases the greater probability, that the output from the washer will still retain an unfortunately high ash content. The ash factor for the run-of-mine output is also subject to wide variations. The first material loaded from a pile just shot down consists chiefly of coarse material and corresponds to a good quality of screened lump. If a number of such mine cars are dumped into the same railway car, such a car when sampled shows a low ash factor, possibly lower than the average normal or vein percentage. On the contrary, if a number of mine cars come to the dump containing a large percentage of clean-up from a room or a number of rooms, such material coming simultaneously into a railway car will cause an ash content for that car to run much above the normal. Doubtless in the long run an average will be maintained which is fairly constant. NECESSITY FOR MINE OPERATORS TO KNOW THE ASH VALUES OF THEIR COAL. Every mine operator should come into possession of the data cover- ing these values, and should develop a log of ash values for the various grades of output from his mine, if any attempt is to be made to submit bids in competition where guarantees as to ash values are required. If tin's knowledge were in hand, serious and very costly errors would be avoided in making contracts. For example, certain of the contracts with the Stale institutions for the fiscal year 1912-1913 guaranteed to main- tain ;in ash content in screenings, "dry-coal" basis, of 12 and 13 per COMMERCIAL VALUATION. 39 cent. As a matter of fact, the deliveries frequently ran as high as 20 and 21 per cent and entailed a penalty of 25 to 35 cents per ton. Some of these discrepancies are doubtless due to a lack of information on the part of the operators regarding the possibility of the earthy contamina- tion which usually accompanies screenings. As a help toward a fuller knowledge of ash values from the various parts of the State, the analytical data presented at the end of this dis- cussion will be found helpful. Over 100 mines have been sampled at their working faces in at least three diffrent points in each mine. Here is a valuable starting point for obtaining the necessary log of ash values for a given mine. Whereas in the tables only the counties are desig- nated for the source of the various samples, the Survey will be glad to furnish the owners of the individual mines the factors for their own face samples, and as soon as further information concerning commercial averages becomes available they will also be willingly placed at the disposal of mine owners. VOLATILE MATTER, FIXED CARBON, AND SULPHUR. Volatile matter, fixed carbon, and sulphur, ordinarily do not enter into consideration in making contract specifications. Pound for pound, volatile matter, as a rule is likely to have quite as high or a higher heat value than the fixed carbon. Modern steam-generating appliances should be able to burn one form as efficiently as the other. House heating appliances, however, utilize a relatively low proportion of the volatile material. In the main, this constituent distils off into the air with but poor or partial combustion, and appears at the chimney top in the form of black smoke. For these reasons the higher fixed-carbon coals are better for domestic use than those high in volatile matter. Ash content, density, and sulphur also enter into the account. Sulphur is present mainly in the form of iron pyrites, and is detri- mental to the value of the coal, especially after its first stage of reduction to ferrous sulphide, FeS. This change occurs at relatively low tempera- tures, from 750° to 900 °F, and produces an easily fusible ingredient which promotes slagging and the formation of clinker. Sulphur is not without some virtue as a heat-producing constituent, however, but its value is low, having a little over J /s the heat of an equal weight of carbon and about 1/14 the heat of an equal weight of hydrogen. Sulphur may be a constituent of coal varying in amount from one to six per cent, and, because of its chemical form and properties, should be looked upon as an ingredient essentially different from the organic matter or real com- bustible material. This feature is more fully discussed under the subse- quent topic of "unit coal." 40 purchase and sale of illinois coal. Duff or Dust. Finely divided material above a certain per cent is more detrimental to the effective combustion of coal than is ordinarily realized. When the percentage of material passing through a screen having ^-inch, round per- forations exceeds a certain amount, the difficulties of operation are greatly increased due to the decreased amount of draft, the unevenness of the fire, the honeycombing of flues, the slagging of arches, and other objectionable conditions. A guaranteed maximum of duff should therefore be established. An excess over such maximum percentage should subject the coal to pen- alty or rejection at the option of the consumer. Calorific Value, relation between quantity of heat contained and true value. Almost without exception the value of a coal is directly propor- tional to the quantity of heat which it contains Yet occasional installa- tions are known where the type of boiler, the setting, draft, grate area, and other factors, may demand certain physical conditions in the fuel that may take precedence even over the actual heat content. But these cases are the exception rather than the rule. It becomes of prime importance therefore to have an accurate knowledge of the heat possi- bilities of a given coal, and, indeed, this is made the principal element in contracting and determining the settlement price for coals marketed on the heat-unit basis. MOST FAVORABLE CONDITIONS FOR DETERMINATION. The calorific values in British thermal units per pound of coal for all the face samples listed in these tables were determined within ten days at most from the time of collection. There is an appreciable loss in heat values of Illinois coals during the first four to six weeks after breaking out from the seam. Hence, for a fair indication of values it is desirable to obtain the heat values under average conditions of mining and shipment. Unit Coal. meaning and application. Attention is specifically called to the heat values for the "unit coal," the pure substance free from ash, moisture, sulphur, and other minor impurities. This value like the coal-bed moisture may be regarded as the normal factor for the actual coal and does not vary in a given mine from year to year. If for example, the average unit value for a given mine is 1.4,350 British thermal units per pound of this material, any sample with whatever content of ash or moisture, when calculated to this "unit coal" basis, will give the same average value within the range COMMERCIAL VALUATION. 41 of experimental error, or about 100 units in 14,000, a variation of less than 1 per cent. This value enables us to check the correctness of the various determinations, any one of which if seriously in error would vitiate the result. Conversely, by reversing the calculation we are en- abled to obtain a close estimate of the heat value present for any given percentage of ash. This is of special value where it is desired to submit a bid for contracting in which a guaranteed heat value is to be indicated. We have given, therefore, in the tables these "unit-coal" values for each mine sampled. The formula by which this value is derived has already been fully discussed in a former bulletin 3 . Therefore the formula only is repeated here. TT ., -, , Dry B. t. u. — 5000 S Umt R L U - = 1.00 - (1.08A + 55S ) In which A is the weight of ash per gram. S is the weight of sulphur per gram. If every mine operator were to obtain as often as possible this "unit" value for his product, he could very shortly derive from an average of his log of values, a basic factor which would be of great advantage to him in submitting propositions for coal supplies. An illustration of such a procedure is given below. A special survey was recently made of certain mines in the five counties named. The average of the "unit-coal" values for each mine may be taken as a constant for the output of that mine. Attention is called to the close agreement between these values and the averages obtained in the more elaborate survey shown in Table 10. Table 8. — Average heat value for unit coal 4 in British thermal units per pound No. County Coal bed Sangamon 5 Sangamon 6 Macoupin 6 Madison . . 6 Vermilion 6 Vermilion 7 Williamson 6 Number of sam- Average — B. t. u. pies averaged "unit coal" 15 14424 5 14340 6 14310 18 14350 19 14597 9 14730 5 14750 CALCULATION OF COMMERCIAL VALUES. The use which can be made of these "unit" values such as are shown in this table may be readily understood when it is remembered that each number represents material which is 100 per cent pure and that 3 Illinois State Geol. Survey, Bull. 16, p. 212, 1909. 4 Pillar and storage coal will have heat units from 1 per cent to 4 per cent below the values here given. 42 PURCHASE AND SALE OF ILLINOIS COAL. for each per cent of inert matter present, such as water and ash, there is a corresponding decrease in the number of heat units present. That is to say, if a coal has 20 per cent water and ash, then 80 per cent of the "unit" value will represent the heat units present per pound of coal as delivered. Indeed, it is possible by taking account of certain refine- ments, such as correction factors for sulphur and hydration of the shaly constituents, to make a calculation which will be of quite sufficient accuracy for basing bids and entering into contracts involving a guar- antee as to heat values. The method of calculation is exceedingly simple and is based on the following expression : Let A = weight of ash per pound of coal. Let S = weight of sulphur per pound of coal. Then — - "Dry" B.t.u. = "Unit" B.t.u. X 1-00 — (1.08A + 0.55S) + 5000S. To illustrate, take the "unit" value for coal from Vermilion County sample No. 6 in Table 8. Suppose we wish to know what heat values can be guaranteed on deliveries from a mine of this group on the basis that we can furnish material averaging as the "dry coal," 12 per cent ash, and 3 per cent sulphur, we will have our total non-combustible material corrected by the above formula as follows : Per cent 1.08A 12.96 0.55S 1.65 Total 14.61 100% — 14.61% e= 85.39%. 14730 X 85.39% = 12578. In this calculation the sulphur has been neglected. It has a small heat value equal to 5000 times the weight of sulphur present or 50 times the percentage number, thus : 50 X 3. = 150 units to be added to the above value, or 12578 150 12728 B.t.u. 5 Deliveries from this mine, therefore, having ash, and sulphur as indicated above can be depended upon as carrying 12728 heat units per pound of "dry" coal, and this factor should be accurate within 100 units in 12000 or less than a variation of 1 per cent from values as they would be determined by direct reading from an instrument. Any other set of values for ash and sulphur would similarly admit of ready calculation and should be used as a basis for calculations involving guarantees of deliveries on a heat-unit basis. If the heat units on the "wet" coal basis are desired assuming, for example, a moisture factor of J 5 per cent, ' ' - iare i ample 1711 Vermilion 6, p. 56. COMMERCIAL VALUATION. 43 the above value as derived for "dry" coal should be multiplied by .85, that is, 12728 B.t.u. X .85 = 10818 B.t.u. per pound of the "wet" coal, assuming a moisture factor of 15 per cent as indicated. In this connection attention should be given to the assumed values which it is proposed to maintain for water and ash. Extended calculations are given in Table 12. ANALYTICAL DATA. Analyses of Mine Samples. In Table 10 are given analyses from 345 coal-bed samples which were taken from 100 mines in the State. They are grouped by coal-beds and counties and represent all of the producing areas of the State. Table No. 9 showing counties and district classification is presented for cross reference. (See Plate I). Table 9. — Alphabetical arrangement of counties. County Coal bed District County Coal bed District Bond 6 1, 2 2 1, 2 1, 2, 6 6 6 6 1, 2, 5 5, 6 1, 2 2 1, 2 1, 2, 6 2, 6 6 1, 2 1, 2, 5 2, 5, 7 2, 5, 7 5 5 6 6 6 2, 6 VII III I III III, VII VII Vlli VI III, IV V III I III III, VII II, VI VI III III, IV I I IV IV VII VII VII I McDonough McLean 1, 2 2, 5 5 1, 2 6 6 5 6 2 6 1, 2 6 5 5, 6 1, 2 1, 2 6 6 5 6, 7 1, 2 6 2 2 6 III Brown I, IV Bureau Menard Mercer IV Calhoun III Christian Montgomery Moultrie Peoria Perry Putnam Randolph Rock Island St. Clair Saline Sangamon VII Clinton VII Edgar IV Franklin Fulton Gallatin Green VI, VII I VII III Grundy Hancock Henry VII V IV, VII Jackson Jefferson Jersey Schuyler Scott Shelby III III VII Knox LaSalle Livingston Logan Stark Tazewell Vermilion Warren Washington Woodford Will Williamson I IV VIII III Macon Macoupin Madison Marion Marshall VII I I VI For a given geological bed the counties represented are arranged alphabetically in Table 10. A further grouping is shown by use of the co- operative numbers, these represent samples from the same mine. Two sets of values are given for each sample — one showing the normal or coal-bed moisture, and the other calculated to the "dry-coal" or moisture-free basis. There is also given the value for the "unit-coal" in British thermal units as derived by means of the formula already presented on page 42. 44 PURCHASE AND SALE OF ILLINOIS COAL. Table 10. — Analyses of mine samples (not exactly indicative of commercial output *) Proximate analysis of coal 1st: "As reed," with total o O Z Q o o o H <^ rH Q County ■a o O moisture. 2nd: "Dry" or moisture free. 3 a 3 cT o 3 (0 o o CO 3 1> s_ -C 3 O 2 u.g < 5229 5230 5231 5338 5339 5340 5363 5364 5365 5359; 5360 | 5361 5371 5372 21 | 7/12 7/12 7/12 19 8/12 19 8/12 19 8/12 19 8/12 19 8/12 19 8/12 8/12 8/12 18 ' 8 /12 17 8/12 17 ! 8/12 Christian Christian Christian Mercer . . Mercer . . Mercer .. Mercer . . Mercer . . Mercer .. Mercer .. Mercer .. Mercer . . Mercer . . Mercer . . 5324 10 8/12 Bureau 5325 10 8/12 Bureau 5326 10 8/12 Bureau 5312 10 8/12 Bureau 5313 1(1 8/12 Bureau 5314 10 8/12 Bureau 5348 8 8/12 Bureau Coal No. 1. 1 11.27 Dry 38.68 43 . 59 40.55 45.70 9.50 10.71 2.07 2.33 .33 .37 11445 , 12898 ' 1 11.52 Dry 38.78 43.83 41.01 46.35 8.69 9.82 2.42 2.73 .97 1.10 11648 13163 1 11.13 Dry 39.21 44.12 41.26 46.43 8.40 9.45 2.56 2.88 .01 .69 11715 13183 1 13.23 Dry 40.29 46.43 37.20 42.88 9.28 10.69 4.37 5.04 .41 .47 11104 12797 1 15.24 Dry 37.66 44.44 35.73 42.15 11.37 13.41 4.80 5.66 1.47 1.73 10353 12214 1 15.15 Dry 39.06 44.44 38.48 42.15 7.31 14.41 3.30 5.66 .17 1.73 11252 12214 1 14.97 Dry 38.27 46.03 37.07 45.36 9.69 8.61 3.75 3.89 .33 .19 9637 13260 1 14.46 Dry 40.42 44.99 35.33 43.61 9.79 11.40 4.23 4.95 .69 .43 10780 1 12749 | 1 14.07 Dry 39.95 47.24 34.01 41.32 11.97 11.44 4.55 4.94 .78 .59 10525 12603 1 1 14.58 Dry 39.49 46.49 36.82 39.59 9.11 13.92 5.60 5.29 .15 .91 10894 ! 12247 : 1 15.07 Dry 38.14 46.23 37.44 43.09 9.35 10.68 4.85 6.56 .34 .18 10790 12754 1 14.10 Dry 39.60 44.91 36.73 44.01 9.57 11.02 3.92 5.71 .23 .38 10956 12705 1 17.75 Dry 39.50 48.03 34.61 42.08 8.14 9.89 5.53 6.72 .86 1.05 10435 : 12687 1 17.50 Dry 38.78 47.00 33.66 40. SO 10.06 12.20 4.51 5.46 .29 .35 10238 12409 Coal No. 2. 16.65 Dry 15.08 Dry 16.83 Dry 14.88 Dry 17.43 Dry 16.07 Dry 15.19 Drv 36.66 43.99 40.12 47.25 36.54 43.93 38.69 45.45 3S.07 46.10 39 . 68 47.28 39 . 67 46.78 38.58 46.29 8.11 9.72 3.40 4.07 .67 .80 10740 12884 36.35 42.80 8.45 9.95 3.68 4.33 .91 1.07 10831 12754 39.19 47.12 7.44 8.95 2.64 3.17 .89 1.07 10788 12970 37.25 43.76 9.08 10.79 3.83 4.50 1.07 1.25 10685 12553 39.44 47.76 5.06 6.14 2.68 3.25 .52 .63 11070 13407 38.36 45.71 5.89 7.01 2.96 3.53 .57 .63 11216 13363 38.69 45.60 6.45 7.62 2.20 2.62 .99 1.17 11206 13213 14666 14707 14779 3.4641 14478 1.4478 14760 iiiii 34551 3.4604 3.4642 14618 14373 3.4372 14533 14431 14463 14357 14462 34571 14480 Rep Bulletin 3, Illinois Coal Mining Investigations, Cooperative Agreement. COMMERCIAL VALUATION. 45 Table 10. — Analyses of mine samples (not exactly indicative of commercial output) — Continued. County Proximate analysis of coal 1st: "As reed," with total moisture. 2nd: "Dry" or moisture free. «2E 21 21 21 6 6 6 5 5 5 7 7 7 14 14 14 13 13 13 12 12 12 8/12 8/12 7/12 7/12 Bureau . Bureau . Christian Christian 7/12 . Christian 8 /12 j Grundy . 8 /12 ' Grundy . 8/12 8/12 8/12 8/12 8/12 8/12 8/12 7/12 7/12 7/12 Grundy Grundy Grundy Grundy Grundy Grundy Grundy Jackson Jackson Jackson 7/12 ! Jackson 7/12 7/12 7/12 7/12 7/12 Jackson Jackson Jackson Jackson Jackson 17.34 Dry 16.97 Dry 12.07 Dry 12.53 Dry 14.30 j Dry 19.97 Dry 18.95 Dry 19 . GO Dry 17.29 Dry 13.73 Dry 17.01 Dry 16.84 Dry 15.81 Dry 16.23 Dry 7.72 Dry 8.77 Dry 9. IS Dry 9.SS Dry 10.91 Dry 9.76 Dry 9.51 Dry 9.37 Dry 9.99 Dry 37.12 44.90 38.66 46.56 39.36 44.77 38.00, 44.12 j 39.54 46.14 38.16 47.68 37.60 46.39 37.01 | 46.06! 38.61 j 46.68 ! 39.87 I 46.22 39.28 47.52 34.83 41.95 41.91 47.66 40.62 46.44 40.30 47.02 37.45 46.79 38.23 47.16 38.16 47.50 36.69 44.36 42.19 48.90 39.48 47.57 36.74 44.27 38.37 46.13 41.19 49.53 39.28 45.48 39.77 47.24 38.71 46.22 40.61 48.47 35.09 38.02 48.56 52.62 32.78 35.93 50.58 55.44 34.70 38.20 51.58 56.80 33.23 36.87 52.43 58.18 33.51 37.61 51.20 57.47 33.45 37.06 52.07 57.71 33.13 36.62 52.12 57.59 33.39 36.48 49.29 54.38 32.51 36.12 51.88 57.63 6.26 7.58 9.54 11.49 6.66 7.57 8.25 9.44 5.86 6.84 4.42 5.53 5.22 6.45 5.17 6.44 7.41 8.96 4.21 4.88 6.77 8.16 3.60 4.34 6.13 7.28 4.45 5.31 8.63 9.36 7.87 8.63 4.54 5.00 4.46 4.95 4.38 4.92 4.72 5.23 5.24 5.79 7.95 8.78 2.25 2.71 3.74 4.26 3.67 4.22 2.00 2.33 1.82 2.27 2.46 3.04 2.03 2.53 2.87 3.47 2.04 2.37 3.32 4.00 1.74 2.09 2.30 2.73 2.47 2.94 2.01 2.18 2.00 2.19 5.62 6.25 1.08 1.20 2.11 2.32 .49 .59 11006 13314 2.29 2.91 10397 12522 .07 .09 11776 13393 .31 .35 11389 13020 .24 .28 11609 13544 .65 .79 10936 13664 .64 .79 10787 i 13309 .83 1.03 10734 13360 1.44 1.74 10708 12947 1.47 1.71 11787 13662 1.05 1.27 .24 .28 .05 .94 1.03 .94 1.03 14612 i4386 i4730 i464i i4702 14603 iiioo i4337 14447 i4466 10834 ! 13055 j 14446 11508 13838 ! 14583 11212 , 13318 14545 11461 I ..... 136S3 14610 12248 13272 14830 12253 ; 13430 148S5 12752 1404C 14S67 12709 14103 14926 12503 i 14034 I 14863 12629 I . 13996 ' 14874 12500 13814 1475S 11972 13208 14671 12308 13673 146S6 46 PURCHASE AND SALE OF ILLINOIS COAL. Table 10. — Analyses of mine samples (not exactly indicative of commercial output) — Continued. d Z CM r-t Q. i-l o - 5105 5106 5107 5516 5254 5255 5256 4756 4759 4760 4764 4766 4768 5034 5037 5038 5040 5042 504:5 5048 5049 5050 7G 77 7/12 i Montgomery 7/12 i Montgomery 7/12 8/12 Montgomery Montgomery 8 /12 j Moultrie 8/12 8/12 3/12 3 /12 3/12 3/12 3/12 3/12 6/12 Moultrie Moultrie Perry . . Perry . . , Perry . . Perry . . . Perry . . . Perry . . . Perry . . . 6 /12 j Perry 6/12 j Perry 6/12 j Perry 6/12 I Perry 6/12 | Perry 7 /12 | Perry 7/12 Perry 7/12 Perry 14.15 Dry 13.83 Dry 13.70 Dry 14.00 Dry 7.07 Dry 7.18 Dry 6.24 Dry 10.32 Dry 10.41 Dry 10.22 Dry 36.96 38.19 10.70 43.05 144.48 ! 12.47 3.43 4.00 36.95 | 39.22 42.88 145.51 10.00 3.72 11.61 4.32 37.25 I 37.93 j 11.12 43.17 I 43.94 12.89 36.88 40.02 42.88 146.54 39.02 41.99 43.01 46.28 38.09 J 41.38 41.03 ; 44.59 40.34 42.55 43.03 I 45 . 38 9.10 10.58 10.90 11.73 13.35 14.38 4.39 5.08 3.84 4.47 3.69 3.97 5.18 5.58 10.87 I 3.18 11.59 3.39 34.03 46.19 I 9.46 I 1.07 37.94 51.51 ! 10.55 1.18 33.43 37.32 33.32 37.11 45.82 10.34 51.14 11.54 47.60 53.03 9.! 1.04 1.15 9.98 33.71 44.91 11.40 .84 Dry ! 37.45 49.88 '< 12.67 ! .93 9.64 33.49 Dry j 37.06 10.05 33.24 Dry |36.94 10.60 Dry 11.20 Dry 10.60 Dry 11.60 Dry 10.82 Dry 10.89 Dry 9.37 Dry 9.34 Dry 10.11 Dry 37.03 41.42 45.60 50.47 11.27 .82 12.47 ; .90 45.85 10.86 .93 50.98 ! 12.08 I 1.04 42.32 47.35 37.29 40.57 42.00 45.69 35.99 ; 43.05 40.25 48.16 37.03 41.89 37.83 42.42 36.81 41.29 36.87 40.68 37.97 41 . 88 36.44 40.54 42.17 47.71 41.52 46.56 41.23 46.27 41.05 45.29 41.32 45.58 41.45 40.12 10.05 13.73 11.23 4.17 10.94 3.20 12.31 3.60 10.36 14.18 11.59 4.67 9.20 10.40 9.83 11.02 11.07 3.71 12.44 4.16 3.84 4.34 2.98 3.34 1.2.71 14.02 11.37 12.54 12.00 13.34 4.62 4.83 3.16 3.48 3.59 3.99 .91 1.06 .91 1.05 1.04 1.20 .48 .57 .46 .49 .23 .25 10547 12285 10728 12455 10444 12102 10761 12511 11912 12819 11573 12468 12149 12957 11395 12705 11486 12822 11270 12553 11205 12447 .35 11230 .39 12428 .62 .70 .34 .39 1.42 1.56 11257 12513 11175 12500 10911 12287 11012 12317 11107 12570 11210 12570 10S26 12277 10936 12067 11099 12243 10915 12141 14329 i-4382 14225 1.4268 14736 14973 1.4937 14380 14367 14383 14452 14394 14424 14365 14288 14228 14301' i4380 143i9 14395 14276 14321 This and two following samples are from a mine not included in the list of 100. COMMERCIAL VALUATION. 55 Table 10. — Analyses of mine samples (not exactly indicative of commercial output) — Continued. 5514 5519 5520 5045 5046 5047 5115 5116 5117 5130 5131 5132 5056 j 5058 5059 5055 I 5060 5061 5077 5079 5080 5108 5109 CJ z a. H 9 £ U.g < 12 A3 Dry 35.55 40.59 12.76 i 35.18 Dry 141.79 12.17 36.42 Dry 41.46 42.86 48.94 44.32 49.34 42.41 48.28 11.38 ! 36.94 40.25 Dry J41.68 45.41 10.62 38.10 39.12 Dry 42.63 43.77 11.39 Dry 36.80 41.04 41.53 46.32 14.97 36.90 Dry 43.39 14.51 I 37.60 Dry : 43.98 12.98 j 38.23 Dry 43.94 15.22 j 38.23 Dry 45.09 13.10 38.86 Dry 44.72 38.36 45.12 39.69 46.43 38.92 44.72 37.36 44.07 37.25 42.86 14.43 38.14 37.07 Dry 44.58 43.32 10.69 40.16 Dry 44.97 12.12 Dry 11.12 Dry 13.06 Dry 11.44 Dry 10.75 Dry 11.35 Dry 10.85 Dry 11.50 Dry 10.99! Dry 13.42 I Dry 38.61 43.93 40.54 45.61 38.21 43.95 38.73 43.73 39.19 43.91 39.68 44.75 40.75 37.87 42.39 40.61 46.22 38.27 43.06 37.36 42.96 38.11 43.04 43.56 38.59 43.54 38.36 45.71 43.03 40.68 45.96 3S.96 43.77 39.23 45.31 37.91 42.84 58.79 43.59 36.92 42.65 9.16 10.47 7.74 S.87 9.00 10.26 11.43 12.91 12.16 13.60 10.77 12.15 9.77 11.49 8.20 9.59 9.87 11.34 9.19 10.84 10.79 12.42 10.36 12.10 11.28 12.64 S.66 9.S5 10.07 11 . 33 11.37 13.09 11.72 13.23 11 . 18 12.53 10.38 11.71 10.04 11.26 9.91 11.20 11.26 12.64 10.43 12.04 4.80 5.48 1.66 1.90 1.96 2.23 4.16 4.69 4.45 4.98 4.11 4.63 3.53 4.16 3.44 4.02 4.32 4.96 4.38 5.17 4.77 5.58 4.55 5.10 3.10 3.52 4.18 4.70 3.21 3.70 4.26 4.81 3.41 3.82 4.05 4.57 4.09 4.58 3.96 4.47 4.36 4.90 4.92 5.69 .15 .17 .59 .67 .58 .65 1.17 1.35 .07 .75 .58 .65 .26 .31 11063 12632 i4422 11357 13018 14458 11200 12753 14414 10823 12212 1.4348 10849 12137 14400 10895 12294 14306 10598 12466 Hhk\ 10911 12763 14373 10845 12463 14368 10579 J 2478 14301 10592 12187 i4268 10495 12265 14292 11063 12387 i4522 11217 12764 14399 11145 12540 144S3 10741 12354 iisis 10841 12242 14447 11041 12371 i4438 11036 12449 14404 11192 12554 i4445 1090S 12597 i44,s2 11047 12411 14544 10753 12419 14474 56 PURCHASE AND SALE OF ILLINOIS COAL. Table 10. — Analyses of mine samples (not exactly indicative of commercial output) — Continued. County Proximate analysis of coal 1st: "As reed," with total moisture. 2nd: "Dry" or moisture free. ._ a> -o g 3 J= O O w 4.10 .57 4.63 .63 3.69 .78 4.10 .86 4.02 .87 4.45 .96 3.95 .68 4.49 .78 5110 5524 5525 5526 4670 4671 4674 4676 4678 4679 4702 4703 4704 4706 4707 4740 4741 4742 4743 4744 47 15 4746 4998 S2 80 80 so 98 08 93 0:i 33 93 92 92 92 95 95 91 91 91 91 9] 93 93 7/12 7/12 8/12 8/12 2/12 2/12 2/12 2/12 2/12 2/12 3/12 3/12 3/12 3/12 3/12 6/12 6/12 6/12 6/12 6/12 6/12 (J/12 65 6/12 St. Clair.... St. Clair .... St. Clair St. Clair Vprmilion . Vermilion . Vermilion . Vermilion Vermilion . Vermilion . Vermilion . Vermilion . Vermilion . Vermilion Vermilion . Vermilion . Vermilion Vermilion Vermilion . Vermilion . Vermilion . Vermilion Williamso' 11.40 40.96 Dry 46.23 10.11 Dry 9.83 Dry 10.19 Dry 39.72 44.19 39.84 44.19 38.44 42.79 13.68 36.28 Dry 42.03 15.50 33.32 Dry 39.43 15.69 34.52 Dry 40.95 14.56 Dry 16.06 Dry 15.95 Dry 15.53 Dry 15.70 Dry 15.27 Dry 11.87 Dry 13.14 Dry 13.58 Dry 13.63 Dry 14.50 ; Dry j 14.20 ' Dry 13.99 Dry 14.79 Dry 15.14 Dry 9.35 Dry 35.04 41.01 34.67 41.32 34.66 41.23 33.60 39.78 32.38 38.81 33.98 40.10 40.37 45.80 .81 44. 35.20 40.73 34.56 40.01 35.98 42.09 35.79 41.71 35.26 40.99 34.44 40.42 33.70 39.72 32.83 36.21 36.89 41.63 38.87 43.24 37.97 42.11 40.41 45.00 41.37 47.92 43.11 51.03 42.22 50.07 41.82 48.95 40.75 48.53 42.06 50.05 39.46 46.70 39.80 47.72 40.88 48.24 39.52 44.86 38.11 43.87 39.83 46.09 41.19 47.69 40.49 47.35 42.05 49.01 42.68 49.63 42.69 50.10 40.19 47.34 50.07 55 . 24 10.75 12.14 11.30 12.57 12.36 13.70 10.96 12.21 8.67 10.05 8.07 9.54 7.57 8.58 10.04 8.52 10.15 7.33 8.72 11.41 13.52 11.36 13.47 9.87 11.66 8.24 9.34 9.94 11.44 11.39 13.18 10.62 12.30 9.03 10.56 7.96 9.28 8.07 9.38 8.08 9.48 10.97 12.94 7.75 8.55 2.78 3.23 1.86 2.20 1.56 1.85 2.03 2.45 1.79 2.14 1.41 1.68 2.32 2.75 2.57 3.04 2.26 2.66 3.07 3.48 4.18 4.82 3.19 2.91 3.36 2.43 2.83 1.83 2.13 1.67 1.94 1.72 2.02 2.50 2.90 1.05 1.16 .46 .62 .74 .90 1.07 1.15 1.06 1.26 .69 .81 1.02 .78 .90 .44 .52 .98 1.14 .98 1.15 ,63 11052 12472 11051 12294 10958 12152 11127 12388 11101 12861 10976 12989 11019 13085 11006 12881 10810 12879 11041 13136 10404 12317 10392 12328 10718 12649 11416 12953 10949 12604 10821 12521 10954 12683 11090 12971 11295 13165 11271 13104 11053 12971 10663 125(55 .26 1 12017 ,29 13256 14511 1436i 14415 14418 14537 i4558 14553 14527 14537 14557 14520 14535 14563 14525 14549 14733 14747 14740 14703 14706 1451.9 14712 14644 COMMERCIAL VALUATION. 57 Table 10. — Analyses of mine samples (not exactly indicative of commercial output) — Continued. d Z d Z CM H as ■a a> Xi Proximate analysis of coal 1st: "As reed," with total moisture. 2nd: "Dry" or moisture free. 3 O o 3 o o .d -1 o o O 03 a County 15 o O 3 O 2 <1> j_ Lug < a. 3 CQ 5004 65 6/12 6 9.99 Dry I 33.79 i 48.56 7.66 8.51 .99 1.10 .06 .06 11899 13218 37.53 ' 53.96 14593 5005 65 6/12 6 8.58 Dry 33.95 37.14 48.31 52.84 9.16 10.02 3.10 3.39 .14 .16 11845 12956 14644 4996 60 6/12 Williamson 6 8.32 Dry 34.61 37.75 47.56 51.88 9.51 10.37 2.-25 2.46' .24 .26 11978 13066 i480l' 5000 60 6/12 Williamson 6 7.53 Dry 34.90 37.74 47.37 51.23 10.20 11.03 3.23 3.49 .60 .65 11799 12760 14607 5006 60 6/12 6 8.81 Dry 32.13 35.62 51.85 56.38 7.21 8.00 1.00 1 1.11 .13 .16 11962 13264 14572 5121 6! 6/12 6 9.44 Dry 33.63 37.13 49.58 54.75 7.35 8.12 1.28 1.42 .19 .21 12092 13354 14685 5133 61 7/12 6 8.99 Dry 34.22 37.62 49.51 54.39 7.28 7.99 1.70 1.87 .04 .04 12149 13349 14674 5134 61 7/12 6 9.38 Dry 33.62 37.10 50.01 55.18 6.99 7.72 1.12 1.24 .14 .10 12138 13394 14654 5122 59 7/12 6 9.79 Dry 33.28 36.89 48.66 53.94 8.27 9.17 1.32 1.46 .44 .49 11891 13181 14681 5123 59 7/12 6 10.67 Dry 32.54 36.42 47.32 52.97 9.47 10.61 1.53 1.71 .15 .17 11619 13006 14748 5124 59 7/12 6 10.96 Dry 33. f4 37.24 45.86 51.49 10.04 11.27 1.72 1.93 .55 .62 11383 12784 14624 5125 62 7/12 6 9.97 Dry 32.20 35.76 49.62 55.12 8.21 9.12 1.47 1.63 .22 .25 11814 13123 14610 5126 62 7/12 6 8.37 Dry 34.19 37.31 50.18 54.77 7.26 7.92 1.03 1.12 .18 .20 12254 13374 14663 5127 62 7/12 6 9.00 Dry 32.93 36.20 49.98 54.97 8.03 8.83 1.03 1.13 .24 .27 12010 13207 14637 5170 64 7/12 6 11.51 Dry 30.75 34.76 49.74 56.20 8.00 9.04 .84 .90 .32 .36 11554 13057 14501 5169 64 7/12 6 9.13 Dry 32.03 35.25 51.06 56.20 7.77 8.55 1.10 1.21 .33 .36 12044 13254 14613 5172 64 7/12 6 7.38 Dry 35.59 38.42 47.56 51.35 9.47 10.23 .86 .93 .51 .55 12017 12974 14617 5180 63 7/12 6 10.38 Dry 32.76 36.56 48.10 53.67 8.76 9.77 1.50 1.67 .16 .18 11735 13072 14672 5181 63 7/12 6 8.78 Dry 34.25 37.54 47.56 52.14 9.41 10.32 2.49 2.73 .53 .58 11885 13029 1475S 5182 63 7/12 6 9.26 Dry 1 33.36 36.76 48.70 53.68 8.68 9.56 1.83 2.01 .39 .43 11955 13176 14761 Coa I No. 7. 5416 99 8/12 La Salle 7 13.82 \ Dry 41.42 48.06 35.90 41.67 8.86 10.27 3.95 4.58 .51 .59 11174 12966 i4744 5414 99 8/12 La Salle 7 12.87 Dry 42.40 48.67 37.35 42.86 7.88 8.47 1 3.86 ! 4.44 .00 .00 11468 13161 14635 58 PURCHASE AND SALE OF ILLINOIS COAL. Table 10. — A?ialyses of mine samples (not exactly indicative of commercial output) — Concluded. CM z H Q. H o Sangamon south of Auburn 6 Perry 6 Randolph 6 Clinton 6 Madison 6 Montgomery 6 » 10 11 12 13 14 15 16 17 18 19 20 4 4 4 4 4 4 4 4 4 4 4 10925 10771 10616 10462 10308 10154 10000 9846 9692 9538 9384 10639 10484 10330 10176 10021 9867 9712 9558 9403 9250 9094 Macoupin 6 Unit coal— 14,400. Coal bed Logan 5 Fulton 5 Sangamon 5 Macon 5 St. Clair 6 Randolph 6 Madison 6 Macoupin 6 La Salle. 5 10 11 12 13 14 15 16 17 18 19 20 11000 10844 10688 10532 10376 10220 10064 9908 9752- 9596 9440 10712 10556 10401 10246 10091 9936 9781 9626 9471 9316 9161 12 For "unit coal" and method of calculation to coal "as-receive< 40-42. 70 PURCHASE AND SALE OF ILLINOIS COAL. Table 12. — Unit-coal values ranging from 14,300 to 15,000 B. t. u. — Continued. Unit coal— 14,500. General location by- counties Ash Sulphur B. t. u. calculated to coal "as rec'd" with 12% moisture B. t. u. calculated to coal "as rec'd" with 14% moisture Coal bed > La Salle 2 Grundy 2 Tazewell 5 Menard 5 Marion 6 Franklin, east of Duquoin anti- cline 6 10 11 12 13 14 15 16 17 18 19 20 4 4 4 4 4 4 4 4 4 4 4 11075 10918 10762 10605 10449 10292 10136 9979 9823 9666 9510 10785 10628 10472 10315 10159 10002 9846 9689 9533 9376 9220 Unit coal— 14,600. Coal bed 10 4 11150 10858 Peoria 5 11 4 10992 10700 12 4 10835 10543 McLean 5 13 4. 10677 10385 14 4 10520 10227 Vermilion . . . 6 L 15 4 10362 10070 16 4 10205 9912 Williamson . 6 17 4 10047 9754 18 4 9890 9597 Jackson 6 19 4 9732 9439 20 4 9575 9281 Unit coal— 14,700. Coal bed La Salle 7 McLean 2 Vermilion 7 Christian 2 Williamson 6 10 4 11 4 12 4 13 4 14 4 15 4 16 4 17 4 18 4 19 4 20 4 11225 11066 10907 10748 10589 10430 10271 10112 9953 9794 9637 10931 10772 10613 10454 10295 10136 9977 9818 9659 9500 9341 COMMERCIAL VALUATION. Table 12. — Unit-coal values ranging from U/,300 to 15,000 B. t. u. Unit coal— 14,800. 71 -Concluded. General location by counties Ash Sulphur B. t. u. calculated to coal "as rec'd" with 8% moisture B. t. u. calculated to coal "as rec'd" with 10% moisture Coal bed Marshall 2 Jackson 2 Saline . 5 * 10 3 11 3 12 3 13 3 14 3 15 3 16 3 17 3 18 3 19 3 20 3 11973 11813 11654 11494 11335 11175 11016 10856 10697 10537 10378 11677 11517 11358 11198 11036 10877 10715 10555 10395 10235 10075 Unit coal— 14,900. Coal bed ■x 10 3.5 12003 11705 11 3.5 11842 11544 12 3.5 11683 11383 Moultrie . . 6 13 3.5 11522 11222 14 3.5 11361 11060 Gallatin . . . 5 , 15 3.5 11200 10898 16 3.5 11038 10739 Saline 5 17 3.5 10877 10578 18 3.5 10716 10417 19 3.5 10555 10256 - 20 3.5 10394 10095 Unit coal— 15,000. 4% moisture moisture Coal bed 10 4 12650 12350 11 4 12458 12188 12 4 12326 12026 13 4 12164 11864 Gallatin . . 5,6 14 4 12002 11702 f 15 4 11840 11540 Saline .... 5 16 4 11678 11378 17 4 11516 11216 18 4 11354 11054 19 4 11192 10892 j 20 4 11030 10730 72 PURCHASE AND SALE OF ILLINOIS COAL. PURCHASE AND SALE OE COAL UNDER SPECIFICATION. Practice of State Board of Administration. Present-day tendencies relating to the basis for coal contracts are reflected in the following quotations : When a proper sample of the coal is secured, the chemical analyses and calorimeter determinations for B. t. u. are a better guide to the value of the coal than are one or two boiler tests for the same purpose. 13 The purchase of coal under specification is as advantageous as a definite under- standing regarding the quality and other features of any other product, or of a building operation or engineering project. The man who buys under specification gets what he pays for and pays for what he gets. 14 The heating value expressed in British thermal units per pound is the most direct measure of the value of coal. Contracts made on what is termed the "heat-unit basis" provide therefore that the amount of money paid shall be in direct proportion to the number of heat units delivered. It is evident also from what has preceded that the number of heat units varies inversely with the quantity of ash and moisture. That the bidder should be thoroughly familiar with these factors in their application to the coal which he proposes to furnish has already been emphasized. A thorough understanding of the methods of awarding contracts is also essential to the dealer who proposes to enter bids on a competitive basis. The conditions under which bids are received, awards made, samples collected, and settlements reached, substantially as prepared for use of the Illinois State Board of Administration in the purchase of coal for the seventeen charitable institution of the State are given on page 78. Use of a Double Standard of Reference. The cost of a given lot of coal must be based upon the weight of the material. The sample taken should represent the coal "as delivered," and, as already emphasized, moisture changes in the sample are to be carefully guarded against. Variations in quality are taken into account by varying the price per ton directly in proportion to the number of heat units delivered. In the award of contracts and in computations for pay- ment, therefore, the calculations are based upon the heat units per pound in the coal "as delivered." Concerning the ash, if there were no other effect produced by ash variations than a corresponding variation in the heat units then no fur- ther account would be taken of that constituent since it would be taken care of in the calculations involving the heat units. However, on ac- 18 The Purchase of Coal: The Arthur D. Little Inc. Laboratory of Engineering Chemistry, pages 10 and 11, L909. " Pope, O. S., Purchase of coal by the government under specifications: V. S. Geol. Survey Hull. 428, page 1<>, 1910. COMMERCIAL VALUATION. 73 count of the expense in handling, and because of a lowering- of efficiency resulting from excessive ash, an additional modification in price is made for this constituent. For greater convenience where comparisons are involved and to eliminate the moisture variable, it is found preferable to refer the ash values to the "dry-coal" basis. This involves the use of a. double standard of reference ; the heat units are referred to the "wet" or "as-received" basis and the ash is referred to the "dry" or "moisture- free" basis. The methods of applying the various conditions involved, in the pur- chase of coal by the Illinois State Board of Administration are given as follows. Bids and Awards. (1). Bidders are required to specify their coal offered in terms of British thermal units "as-received," but ash is specified on the "dry-coal" basis. These values become the standards for the coal of the successful bidder. (2). In order to compare bids, all proposals are adjusted to a com- mon basis. The method used is to merge all three variables — ash, calorific value, and price bid per ton — into one figure. This figure will be the cost in cents of 1,000,000 British thermal units and is derived as follows. (a). All bids are adjusted to the same ash percentage by selecting as the standard for comparison the proposal that offers coal containing the highest percentage of ash. Each 1 per cent of ash content below that of this standard will be assumed to have a positive value of 2 cents per ton, and accordingly the price will be decreased *2 cents, which is the amount of premium allowed under the contract for 1 per cent less ash than the standard established in the contract. Fractions of a per cent will be given proportional values. The adjusted bids will be figured to the nearest tenth of a cent. (b). On the basis of the adjusted price, allowance will then be made for the varying heat values by computing the cost of 1,000,000 British thermal units for each coal offered. This determination will be made by multiplying the guaranteed British thermal units per pound by 2,000 and dividing the product by 1,000,000. This factor gives the guaranteed number of million units per ton of delivered coal. Dividing the ad- justed price as found under (a) by this factor gives the cost per million heat units. A convenient form for tabulating bids to indicate the various factors entering into the final computation of cost is shown below. 74 PURCHASE AND SALE OF ILLINOIS COAL. Table 13. — Convenient form for tabulating bids. Coal offered Guarantees Price per ton 2000 lbs. Computed No. Ash in "dry coal" (per- cent) B. t. u. "as re- ceived" As bid As adjust- ed for ash 11 (a) cost in cents per 1,000,000 B. t. u. 11 (b) A B Vermilion Co. Screenings Sangamon Co. Screenings 17 16 14 10300 10400 12500 1.50 1.35 2.00 1.50 1.33 1.94 7.3 6.4 C Williamson Co. Screenings 7.8 Price and Payment. Payment for coal specified in the proposal will be made upon the basis of the price therein named, which has been corrected for variations in heating value and ash from the standards specified in the contract, as follows : (a). Considering the guaranteed heat units on the "as-received" basis, the correction in price will be a proportional one and is determined bv the following formula : B. t. u., delivered . . = — r X bid price = price corrected tor B. t. u. B. t. u., guaranteed The correction is figured to the nearest tenth of a cent. (b). For all coal that by analysis contains less ash on a dry-coal basis than the percentage guaranteed, a premium of 2 cents per ton for each whole per cent less will be paid. An increase in the ash content of 2 per cent above the standard established by the contractor is toler- ated without exacting a penalty. When this excess is greater than 2 per cent, deductions are made in accordance with the following table : COMMERCIAL VALUATION. Table 14. — Showing deductions for excess ash 15 . Cents per ton to be deducted Ash as No deduc- estab- 1 Maxi- lished tion for 2 4 7 12 18 ; 25 35 mum in pro- limits below limits posal for ash Percentage of ash in "dry coal" Per cent 5 7 7- 8 8- 9 9-10 10-11 11-12 12-13 13-14 12 6 S 8- 9 9-10 10-11 11-12 12-13 13-14 14-15 13 7 9 10 9-10 10-11 10-11 11-12 11-12 12-13 12-13 13-14 13-14 14-15 15-16 16-17 14 8 14-15 15-16 14 9 11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 15 10 ...... 12 13 12-13 13-14 13-14 14-15 14-15 15-16 15-16 16-17 17-18 16 11 16-17 17-18 18-19 16 12 14 14-15 15-16 16-17 17-18 18-19 19-20 17 13 15 15-16 16-17 17-18 18-19 19-20 20-21 18 14 16 17 16-17 '17-18 17-18 18-19 18-19 19-20 20-21 20-21 21-22 21-22 19 15 19-20 19 16 18 18-19 19-20 20-21 21-22 22-23 20 17 19 19-20 20-21 21-22 22-23 21 18 20 20-21 21-22 22-23 22 As an example of the method of determining the deduction in cents per ton for coal containing ash exceeding the standard by more than 2 per cent, suppose coal delivered on a contract guaranteeing 10 per cent ash on the "dry-coal" basis shows by analysis between 14.01 and 15 per cent (both inclusive), or, for instance, 14.55 per cent, the deduction ac- cording to the table is 7 cents per ton (reading to the right on line beginning with 10 per cent on the extreme left, which in this case is the standard, to the column containing "14.01-15," the deduction at the top of this column is seen to be 7 cents.) Note — If the ash standard is an uneven percentage, the table will be revised in order to determine deductions on account of excessive ash. For example, if the ash standard is 6.53 per cent, each percentage value beginning with 6 in the left-hand column and all figures in the line read- ing to the right of G will be increased by 0.53. There would be no deduction then in price of ash in delivered coal up to and including 8.53 per cent, whereas for coal having an ash content, for instance, between 11.54 and 12.53 per cent the deduction would be 12 cents per ton. Specific Directions for Sampling. Since payment for coal is based upon the quality of the coal delivered as shown by analysis of representative samples, it is imperative that 15 Bulletin 378, United States Geological Survey, Results of Purchasing Coal under Government Specifications. 76 PURCHASE AND SALE OF ILLINOIS COAL. samples representing every invoice of coal be taken and that the proper officials of the various institutions see that such samples are obtained. If desired by the coal contractor, permission will be given to him or his representative to be present and witness the collection and prepara- tion of the sample. TAKING THE SAMPLE. The sample should be taken from the car during the process of un- loading. An occasional half shovelful should be thrown into some receptacle such as a clean barrel or garbage can with cover so that by the time the car is unloaded, approximately 200 pounds evenly distributed throughout the load will have been taken. This will mean about one- half shovelful for every ten full scoops. They are best taken in the process of shoveling from the bottom of the car, since the top coal rolls down and mixes fairly evenly with the bottom. It should be kept in mind that in taking a sample there must be obtained the different sizes of coal, fine and coarse in their proper proportions from the entire cross section of the mass, and also an even distribution of the same length- wise of the car. Especial care must be taken to guard against loss of moisture in the process of collecting and in reducing. the gross sample. REDUCING TPIE SAMPLE. In the case of "run-of-mine" coal the largest pieces must be broken down. For this purpose empty the same upon a clean platform or con- crete floor about 10 feet square, spread out in as thin a layer as possible, and crush with the tamper until all lumps are reduced so that none will exceed 1 inch in any diameter. Pieces of bone coal, pyrites, and other impurities should be crushed to at least ^4-inch size. Retain all of the sample on the platform, and shovel over three times in order to thoroughly mix the fine and coarse particles. Spread the coal again over the platform, and then pile into as sharp a cone as possible by throw- ing from the outer margin into the center. Noav press out the cone with the shovel or a broom held firmly on top of the pile while moving around the same, till the mass is flattened into a circular shape about 4 inches deep. With a board or straight edge divide the mass into four equal sectors. Reject two diagonally opposite quarters. In the case of screenings or slack no tamping to break down lumps is necessary; mix, cone and quarter as just described, throw one of the quarters into a box for determining the duff, as directed below. Thoroughly mix the sample again as at first and repeat the quartering and mixing until a sample of approximately 50 pounds lias been obtained. COMMERCIAL VALUATION. 77 DETERMINATION OF PERCENTAGE OF DUFF OR DUST. Ordinarily the percentage of fine material in screenings or slack is required ; hence the determination must be made upon some part of the original sample which has not been crushed or reduced in size. For this purpose, therefore, one of the first quarters should be taken as in- dicated above. This quarter should be placed in a box or tub, the weight of which is known or which has been counterpoised, and the weight of the quarter carefully taken. The weight of the sample without the box should be noted on a slip of paper. From this box the material should be sifted through a screen having ^4-inch openings, and the fine material caught in • a second box which has been counterpoised, or the weight of which is known. The sifted material is now weighed, and the weight of dust without the box noted on a slip of paper having the first weight. This slip bearing the two weights together with the additional memoranda note below should be inserted in the can on top of the five- pound sample before sealing, and transmitted in this form along with the coal sample. OBTAINING A 5-POUND SAMPLE. When the amount of the sample has been brought down by quarter- ing to about 50 pounds the size of the particles of coal should be reduced again by grinding through a mill to T /£-mch size. The entire 50 pounds is thus put through the mill and then through the riffle until about 5 pounds are obtained. This sample should entirely fill the can, and it is necessary to take all of a sample as obtained by the riffle. For example, if upon riffling for the last time, an amount is obtained which will more than fill the sample can, it should not be discarded, but the can should be emptied and added to the excess and re-riffled. One-half thus obtained should be put into the sample can and the other half riffled again and one of the halves thus obtained added to the sample can. Riffling in this way should be continued until the sample can is nearly or completely filled. Note especially that all dust made during grinding should receive the same treatment as the rest of the sample and not be discarded. When a sample has thus been obtained the memorandum slip showing the date, car initial and number, shipper, weight of car content, weight of quarter taken for dust, and weight of dust 16 should be ' put inside of can. The cap should be screwed firmly in place and scaled with electrician's tape. The name of the institution, date, number of car, kind of coal, should be carefully indicated on the can and transmitted at once to the chemical laboratory. 16 See suggested form for ticket on page 2G. 78 PURCHASE AND SALE OF ILLINOIS COAL. COMPOSITING OF SAMPLES. Compositing of the several 5-pound lots is accomplished preferably at the laboratory and should conform to the following schedule : For contracts calling for less than 10,000 and more than 3,000 tons five car samples shall enter into the composite. For contracts calling for less than 3,000 tons and more than 1,000 tons, samples will be taken and analyzed for each car. The amount of each car sample taken for compositing shall be pro- portional to the gross car lot from which it comes, so that the assembled mass shall be composed of the same proportion of each of the several cars represented in the composite sample. Summary of Coal Settlements under Specification For the Fiscal Year 1913-1914. A summarized statement is given below in tabular form showing the kind of coal under contract, the guaranteed dry ash, and B.t.u. as re- ceived. The settlement prices, premiums, and penalties, as given rep- resent the net results of the numerous settlements under each contract. Table 15. — Summary of coal settlements Illinois State Board of Administration fiscal year 1913-1J,. Institution Kind of Coal Anna Slack Chicago Screenings Chicago Mine run Elgin Screenings Jacksonville Mine run Jacksonville . Screenings Kankakee . . . Mine run Kankakee. . . Screenings Watertown . . Screenings Soldiers and Orphans' Home Mine run Soldiers' and Sailors' Home Slack Soldiers' and Sailors' Home Mine run Soldiers' and Sailors Home Screenings Guaran- teed ash "dry" 16.00 16.00 13.00 16.00 14.00 17.00 15.00 16.00 17.00 14.00 17.00 14.00 15.00 Guaran- teed B.t.u. "as rec'd" 11,600 11,620 11,830 11,040 10,600 10,500 11,200 11,350 10,000 10,600 9,700 10,600 9,700 'Average Contract settle- price per ton ment price per ton $1.49 .94 .16 ,05 .64 .40 .90 .70 1.50 1.74 1.49 1.53 Total premium $1,410' 1.942 2.190 2.014 1.583 1.296 1.827 1.655 1.50 1.727 1.604 1.95 1.991 1.479 p 26.20 104.60 445.50 10.04 Total penalty $841.00 259.60 285.60 515.04 287.74 703.76 .08 47.04 295.44 COMMERCIAL VALUATION. 79 Table 15. — Summary of coal settlements Illinois State Board of Administration fiscal year 1913-14 — Concluded. Institution Girls' Train- ing School Boys' Train- ing School School for the Blind. School for the Deaf. . Lincoln School and Colony. . . Lincoln School and Colony. . . Peoria Kind of Coal Screenings Mine run Mine run Mine run Screenings Mine run Mine run Guaran- teed ash "dry" 14.00 14.00 15.00 14.00 15.00 14.00 15.00 Guaran- teed B. t. u. "as rec'd" 11,480 12,100 10,700 10,600 9,700 10,600 10,500 Contract price per ton $2.15 2.65 1.70 1.64 1.16 1.35 1.48 Average settle- ment price per ton Total premium $2,122 2.508 1.685 1.584 1.229 1.272 1.504 80 168.00 Total penalty $110.16 1,004.56 28.30 307.36 46.60 Difference $3537.14 Totals $1195.14 4732.28 80 INDEX. A Page. Ash, determination of 35 Percentage of, in dry coal 75 Variations of 15 > 35 Award of contracts '3 B Bids JjJ Bureau, analyses of samples from 44, 45, 59 Unit-coal values for 70 Calorific value 40 Carbon, fixed, determination of 39 Christian, County, analyses of samples from. 44, 45, 60 Ash in coal from 36 Clinton County, analyses of coal from.. 51 Unit-coal values for 69 Composite samples 25, 78 Commercial sampling 20 Commercial values, calculation of 41 D Duquoin anticline, moisture in coal near. 35 Dust, determination of 26, 40, 77 E European coal, comparison with Illinois type 29 F Face samples, moisture in 30 Face sampling 17 Franklin County, analyses of samples from.. 51, 25, 63 Unit-coal values for 70 Fulton County, analyses of samples from . 47, 61 Unit-coal values for 69 G Gallatin County, analyses of samples from 47, 48, 52, 63, 68 Unit-coal values for 70 Grinder, use of 20 Grundy County, analyses of samples from 45, 59 Unit-coal values for 70 H Heat-unit basis 9, 72 I Institutions, coal contracts with 78 J Jackson County, analyses of coal from 45, 46, 52, 60, 64 Unit-coal values for 70,71 L La Salle County, analyses of samples from 46, 48, 57, 58, 59, 68 Unit-coal values for 69, 70 Logan County, analyses of samples from.. 48, 61 Unit-coal values for 69 M Mac on County, analyses of samples from 48, 62 Unit-coal values for 69 Macoupin County, analyses of samples from. 52, 53, 64 Moisture in coal from 30 Unit-coal values for 69 Madison County, analyses of samples from. 53, 65 Ash in coal from 36 Moisture in coal from 30 Marion County, analyses of samples from 53, 67 Unit-coal values for 70 Marshall County, analyses of samples from 46, 59- [Tnit-coal values for 71 Page. McDonough County, analyses of samples from 46 McLean County, analyses of samples from 46, 47, 49, 68 Unit-coal values for 70 Menard County analyses of samples from. 48 49,61 Unit-coal values for 70 Mercer County, analyses of samples from 44, 60 Unit-coal values for 70 Moisture, changes of 28 Coal-bed, relation to commercial mois- ture 29 Control of 16 Montgomery County, analyses of samples from 54, 65, 66 Unit-coal values for 69 Moultrie County, analyses of samples from 54, 68 Unit-coal values for 71 P Payments for coal 74 Percentages of constituents on basis of moisture 29 Peoria County, analyses of samples from 49, 60 Unit-coal values for 70 Perry County, analyses of samples from 54, 55, 64, 66 Unit-coal values for 69 Prices 74 R Randoph County, analyses of samples from.. 55, 67 Unit-coal values for 69 Riffle, use of 20 Run-of-mine coal, reduction of sample of 76 S St. Clair County, analyses of samples from.55, 56, 66 Unit-coal values for 69 Saline County, analyses of samples from. 49, 59. 60 Moisture in coal from 35 Unit coal values for 71 Sampling, care in 11 Directions for .....17, 75, 78 Kit for 19 Method of 76 Principles of 11 Sangamon • Countv, analyses of samples from '. 50, 51, 55, 61, 62, 65 Ash in coal from 36, 37 Moisture in coal from 30 Unit-coal values for 69 State Board of Administration, purchase of coal by 10 Sulphur, determination of 39 T Tazewell County, analyses of samples from. 56, 69, 71 Unit-coal values for 70 U Unit-coal, meaning and application 40, 69-71 V Vermilion County, analyses of samples from. 56, 58, 67 A sh in coal from 27 Determination of Moisture in coal from Lmit-coal values for 70 W Williamson County, analyses of samples from 57, 64 Ash in coal from Unit-coal values for Moisture in coal from