It is estimated that the original coal beds of Illinois con tained more than 200,000,000.000 tons of coal. The amount mined from 1533 to 1917 is 1.212,000.000 tons. During the last 10 years of this period 577,000,000 tons were produced, almost as much as during the preceding 75 years.
About 1 per cent of the total coal supply of the state has been exhausted in 85 years, including the coal which could not be recovered in the mining. With the tremendous rate of increase in output by years and by decades, the coal supply will be used much more rapidly in the future than in the past. Illinois has a larger known coal reserve than any other state in which the coal fields are well surveyed, probably twice as great as that of Pennsylvania, where the present annual output of coal is four times that of Illinois. The United States con tains more coal than the rest of the world. Illinois contains about 10 per cent of the coal of the United States. Another 85 years of coal mining in Illinois will develop problems of pro duction and consumption of coal not yet fully appreciated.
The 79,000,000 tons of coal mined in Illinois in the year ending June 30, 1917, came from 51 counties and S10 mines. The 324 "shipping" mines produced 98 per cent of the total, the remaining 2 per cent coming from 486 "local" mines. The average production of the shipping mines was 238,000 tons; that of the local mines 3,200 tons. The production of 266 mines was under 1,000 tons each; 139 mines each produced more than 200,000 tons. The coal-mining operations of 1917 required the labor of 80,893 men; 96 per cent of these were employed in the shipping mines; 70 per cent of all the men were employed in the 139 mines whose production exceeded 200,000 tons each, and the output of these 139 mines was 78 per cent of the total for the state.
The production of coal by counties for the year ending June 30, 1917, is shown on the map (p. 201). The numbers are given in thousands of tons and, in reading, three "ciphers" (000) must be added 1.o each number.
Of the 810 coal mines of the state, 480 are shaft mines, 204 are drift mines, and 126 are slope mines. There are 779 mines worked by the "pillar and room" method; 23 by the "long wall" method; and S by the "strip" method. The electric motor is rapidly displacing other methods of underground haulage in the large shipping mines. In 1907 underground haulage was carried on in 75 shipping mines by motor, 26 by cable, 503 by mule, and 5 by hand. Ten years later, in 1917, 200 shipping mines used the electric motor, 51 the cable, 113 the mule, and 1 was oper ated by hand. Machine
mining is also having a rapid development. In 1900, 3S mines were operated exclusively and 29 in part by machines in 1917 these numbers had increased to 9S and 53 respectively. The number of machines increased during this period from 430 to 1,920 and the amount mined by machines from 5,500,000 tons, or one fifth of the production of the state, to 47,000,000 tons, or three-fifths of the total.
Depth of mine, thick ness of seam, and pro duction per mine vary greatly. In the "strip" mines the overlying soil is removed and the coal taken from the sur face. Drift and slope mines may be only a few feet below the surface of the earth. In Mc Donough County there are 4S mines; 10 are shaft mines, 4 are slope mines, and 34 are drift mines. The depth of coal below the surface varies from 22 feet to 70 feet. The thickness of the worked coal seams varies from 1 foot S inches to 2 feet S inches. The production per mine varies from 10 tons to 2,440 tons. The total output of the 4S mines is 17,600 tons. Thus while Mc Donough County has 6 per cent of the mines of the state, the coal pro duction is a very small fraction of 1 per cent. Franklin County has 21 mines; all are shaft mines; the depth of the mines varies from 152 feet to 730 feet; the thickness of the worked coal seams from 6 feet 6 inches to 14 feet; and the output per mine from 45,000 tons to 1,093,000 tons. Franklin County has 2 per cent of the mines of the state and produces 14 per cent of the coal. The deepest mine in Illinois, 1,004 feet, is at Assumption, Christian County. Fivc counties—Bond, Cass, Jersey, Moultrie, and White—have but one mine each. In each of three counties there are more than 50 mines; Peoria has 60, St. Clair 63, and Fulton 93. The 321 shipping mines are found in 3S counties. One mine in Peoria County shipped its production of 25,000 tons by boat on the Illinois River. The 323 other shipping mines disposed of their coal by shipment over 37 different railroads. The Illinois Cen tral served 89 mines in 21 counties, carrying 10,000,000 tons, 19 per cent of the 53,000,000 tons shipped in the state. The Chicago, Burlington, and Quincy Railroad served 51 mines in 11 counties, carrying 9,S00,000 tons, or 18 per cent of the total. The "Big Four" Railroad served 37 mines in 10 counties and carried 12 per cent of the total. The Chicago and Eastern Illinois Railroad served 33 mines in 6 counties and carried nearly 10 per cent of the total.