SYMPOSIUM OX CONSERVATION 63 



well as from our own producers. The miners are better organ- 

 ized and secure higher wages, in Illinois than in the principal 

 competing States. In West ^'irginia, where the men are prac- 

 tically unorganized, coal was sold at the mine in 1910 at a price 

 averaging 20 cents less per ton than in Illinois. This condition, 

 together with low freight rates to Chicago and superior quality 

 of the eastern coal, enables it to sell in our natural markets. 



The latest available data for years not affected by wage dis- 

 turbance, indicate an average selling price of $1.41 at the mines 

 in northern Illinois and $0.88 to $1.15 in other districts. The 

 average cost, including general and selling expense and amortiza- 

 tion, averages $1.20 to $1.30 for the northern long-wall district 

 and $0.70 to $0.95 in the other districts. The best gross profit 

 probably does not exceed 20 cents, and when interest on the 

 invested capital is deducted the net profit is reduced to 10 or 15 

 cents per ton : the average net profit throughout the State is 

 probably much less than these figures. It is readily seen, there- 

 fore, that under present conditions it is nearly impossible to 

 increase the percentage of mining extraction when this will 

 increase mining costs. 



Wasteful Mining Methods. 



The above considerations show the controlling causes for the 

 waste of about 50 per cent of our coal in mining. It is desirable 

 next to consider the ways in which the coal is lost beyond 

 recovery. They are due, in order of importance, to 



1. System of mining. 



2. Carelessness in operation. 



3. Irregular boundaries of property. 



Losses Due to System of Mining. Two general systems of 

 mining prevail, as determined chiefly by the character of strata 

 overlying the coal. The long-wall method of northern Illinois 

 yields 90 to 95 per cent of the coal ; but the room-and-pillar 

 method, which is elsewhere in practice, commonly yields only 40 

 to 60 per cent. 



\\'here the long-wall method is used, the coal averages 3 feet 

 in thickness, and the roof is composed of shale, which settles 

 gradually as the coal is removed. The miner undercuts the coal 

 to a distance of 4 to 6 feet and the pressure of the roof breaks 

 it down. -^Meanwhile props are set parallel to the face, so as to 

 maintain a working place, along which fresh air circulates. 

 Fallen shale and other refuse are continually piled behind the 



