THE COLLIERY GUARDIAN AND • JOURNAL OF THE COAL AND IRON TRADES. Vol. CXIII. FRIDAY, JANUARY 19, 1917. No. 2925. Dry Preparation of Bituminous Coal in Illinois: I.—Tipples.* By E. A. During the year ended June 30, 1915, the mines of Illinois produced, 57,601,694 short tons of coal valued at the mines at about 1*14 dols. per ton, or a total value of 65,665,931-16 dels. Of this total, about 4,000,000 tons w6re treated by washing, while 53,600,000 tons were prepared' to a greater Or less degree in the dry'state, principally by screening or sizing, and by picking. The run of mine coal produced amounted to more than 10,000,000 tons, or 17*3 per cent, of the total; lump coal, 19,200,000 tons, or 33-3 per cent.; egg coal, 8,700,000 tons, or 15;1 per cent.; nut coal, 3,800,000 tons, or 6-7 per cent.; and pea, screenings, and slack coal, 15,900,000 tons, or 27-6 per cent. The lump is made over screens ranging from a fin. up to 8 in. round hole. If the coarser ■ sizes’ o*f screens, with 5 in. or 6 in. holes are used, the coal is passed over another set of screens having perhaps 3 in. round' holes/ the .oversize produced being'called egg’coal. Nut coal , includes sizes made between 1 in. and 3 in. round hole screens. . Pea coal is somewhat smaller, generally belpw 1 in., and having only the finest sizes, say, under /a in. round or square hole, taken out. The smallest sizes of coal remaining after these processes form slack.. The term “ screenings’” usually refers to sizes of coal passing 2 in. or 1J in. round -hole screens, from which no smaller sizes have been taken.’ The washing prepara- tion in.Illinois is confined entirely to coal under 3 in. in size. ■ In were most.bituminous coal fields the first seams mined .thick, and contained, the^best quality of coal with . Fig. 1.—Elevation of Class I. Tipple. eon a minimum of impurities. At first only lump coal was considered of value. Later it became necessary to mine relatively impure seams or thinner seams, which, owing to the admixture of roof and floor impurities with the smaller amount of clean coal, might produce a coal which is relatively impure, and which must be cleaned . and otherwise prepared for the market. Consumers also become more exacting as to size and quality of the fuel, and the general increasing value. per ton permits more careful preparation, of the , impure coal and of the smaller sizes. In Illinois close preparation has been developed, although scarcely | per cent, of the coal resources have been extracted. The attention given to careful prepara- tion has been increasing since the early ’nineties, the progress during the past seven years having been especi- ally marked. . The causes for this development are.:— (1), The .introduction of State laws regulating the weigh- ing of coal and the. basis of payment to the miner for his. coal; (2) the various struggles . and consequent agreements, between operators and miners dealing chiefly with payment for mining and with, the cleaning of coal; (3) the demand of the consumers, who, having . become educated by, the publicity given during the past few years to the purchasing of coal on specifications, are no longer content with the grades of coal they received a decade ago; (.4) the campaigns waged by the cities to abate the smoke nuisance; (5) the excessive competition among producers, caused not only by the operation iof tod many mines, and the consequent desire to keep these in constant operation; but also by the maintenance of highly-organised selling departments, which have a tendency to introduce new sizes and trade names for coal; and (6) the general introduction of improved machinery used in coal mine tipples to prevent breakage and facilitate preparation. Historical Development of Illinois Preparation Practice. In-the early period of mining in Illinois,, the practice of . selling coal as brought to the. surf ace, with no attempt ■* University of Illinois Bulletin No 88. - HOLBROOK at preparation before shipment, was generally followed. A rough separation of the fines from the lump coal took place underground at the face, and during the period of Loading the coal into the mine cars, for which purpose use was made of a’tined fork, having spaces between the tines, of from fin.'to l|in. This allowed the finer coal to pass through the fork, after which it was thrown back into the gob and left in the mine. The common round hand screen, or coal miner’s riddle, with square mesh wire cloth., having perforations varying from -Jin. to 2 in. in size, was also used by the loaders under- lump or Mine Kun •fif'ffnrit' or Mine Run Nut or Slacker Nut andSlaat Engine Mouse Class II. Tipple. Mouse MilO I50N.P ELEVATiON Fig. 2.—Ground Plan and End Elevation of Boner 150 HP ground for screening out the smaller coal which was left- in the mine, and for carrying the coarser coal to the mine car. The rake and pan method of loading was also formerly in common use. After the largest lumps of coal had been loaded into the mine car by hand, the remainder was raked on to an iron or wooden plate or pan, and transit erred to the mine car, ’while the fine coal and dirt not gathered ,by the rake were left in the mine. The purpose of the pan was to have only clean lump coal carried to the pit box or car; and whether this coal was loaded on the pan by hand, or scraped on by a rake or fork, the end attained was the same. Another common method of preparation underground was by the use of “ grills,” or wooden bar screens. These were wooden bars, spaced j-.in. to 2 in,, apart, nailed into a wooden framework, and set up at an angle of about 45 degs. The coal, before being loaded, was ; shovelled against these bars. . The finer coal which passed through the bars was left in the mines, and the oversize was re-handled and loaded.' ; As the mines' grew, as steam hoists and improved systems of. underground haulage were generally intro- duced, and. when labour cost underground and the value of fine coal or screenings increased, the coal was hoisted as mined, and prepared in the mine surface buildings, or tipple. The introduction and use of the automatic stoker, with fine hole or chain grates, and other .special grates which made possible the generation of power from the finer sizes of coal, were important factors in the increase in use and value of these small sizes of coal. ... ■ Such devices were introduced into Illinois about 1890, and during the succeeding 10 years their use in large power plants became general. Then the consumer with the average. steam plant realised the possible saving through their use in connection with cheap coal screenings, and within a few years these stokers became common. Now, there is a constant demand for the once despised waste product, coal mine screenings.■ Formerly payment to the miner and operator alike was made almost wholly on the basis of the bushel, there being usually 25 to 28 .bushels to the ton. By 1880 some of the larger mines had adopted weight by scales as a basis of payment, s-Uch weights, being taken by company men, whilst others, still adhered dp the volume basis. This naturally led to considerable trouble between operator and miner, and after some years.of continued friction and legislation, a joint conference of miners and operators was held at. Joliet in 1897, and the gross weight scale was adopted- for' the entire field. Subsequent’ agreements between operators 'and workers provided .fines for men sending up refuse with the coal, t and at present every possible means is being taken to compel the loading of coal free from impurities. The present demand of the consumer for clean coal has made it necessary that care will be taken to load, at least as regards lump coal, only pieces that will pass inspection by the company coal inspector. Recent Developments. By 1900,1 sizing and close preparation had become important enough to justify the separation of the total production into the separate sizes produced. The public was beginning to demand sized coal. Fresh impetus to this demand was a result of the- anthracite strike of .1902, when the public, deprived of closely-sized anthra- cite, tried sized Illinois bitu- minous coal for the. first time as a substitute. In the period from 1902-1907 many of the small companies were consoli- dated, and laager corporations entered the field and erected new and laager modem steel surface plants. The period from 1907 to 1915, especially the last five years, is notable for the .re-modelling of coal tipples to handle larger . outputs, and to meet the grow- ing demand for cleaner and more evenly-sized coal. This has necessitated''improvements in mechanical details, such as weighing devices, sizing • . . screens, , picking tables, rand ’ loading booms, and has caused ..■•the 'introduction ! of special engineering features in im- - proved re-screening plaints,' and special dry: processes for clean- ing the- coal. ; A surface plant in Illinois must be capable of handling more than 4,000 tons per eight-hour day in order to be considered one of large capa- city. At a mine in Macoupin county recently, a record has been made of 5,116 tons'hoisted and prepared in an 8-hour day, , or an average of 640 tons per hour. Comparing this with a record of 1,655 tons hoisted in 9^ hours, or about 174 tons per hour-, made at Braidwood, Illinois, in 1888, it is evident that remarkable changes have taken place not only in underground methods, but in weighing, handling and general preparation at the surface. The large increase in capacity of individual mines has at times tended towards over-production, with a conse- quent decreased profit per ton and increased competi- tion,- The average shipping mine in Illinois is operated ■a