Show WASTEFUL MINING METHODS fifty fire per cent of the ihn coal la in th abe beds rendered Ilca Rea dered unavailable while other plans of coal mining have been proposed writes II 11 M chance in an article on the anthracite coal industry du stry in the engineering magazine the old method of working by parallel breasts separated by regular pillars of coal is still almost universally used that great waste results from this method is admitted by all in working thin beds the pillars can be demov removed ed rat at least a large port portion ion of the coal they hey contain can be taken take n out after the rooms have been worked to the limit out this can be done to very limited extent in thick seams by adopting modifications in the long wall system or combined long wall and refining refilling systems a much larger percentage of coal ln in the thicker seams could be recovered but such systems would perhaps increase the cost per ton una and they require ire a large preliminary outlay in headwork dea dwork before mining on a large scale can be commenced cousert conservative active estimates estimate place the quantity of coal lost by being left in the ground as pillars at forty per cent of the quantity originally present the cost of mining and preparing coal for the market varies widely between different collieries colli eries when the I 1 coal is wet and contains much bony coal or slate the cost of preparation is largely increase increased ea perhaps one dollar and forty cents to one dollar and ninety cents per ton may fairly be taken as the average in cost of production and preparation this is exclusive elusive of royalty which averages from thirty cents t to 0 forty cents per ton enormous quantities ties of water are pumped from some C of I 1 the mines some of them r raising between one M million and two million gallons daily in addition to the co coal al lost in pilla pillars left ta to 0 support the roo roof 1 a considerable portion is is lost by becoming mixed with the gob or refuse left in the mine f no is reduced to dust by blasting and handling still more waste is made by cT casker crashing hn screening and handling in th the b breaker and d t the he r rejected slate lt away has more or less coal adhering to to it which is lost in the waste dump less tharl than forty five per cent of the coal ca contained in the tha thicker beds is ia sent to market the balance being wasted aasted |