of coal, and these
are of larger size, so that there is less danger of accidents. Wherever
possible they use timbers of wood instead of these smaller pillars of
coal. They also mine as near the top of the seam of coal as can be done
safely, and so regulate the blasting that much less slack is made than
by the heavy discharges. These changes in mining methods save a far
larger proportion of coal, and also prevent many accidents, which are
the most unfortunate feature of coal mining, and the one which should
receive most careful consideration. (See chapter on Health.)

One large mining company in Kentucky raises its own timbers by planting
trees in straight, close rows on its coal land, thus making the land
produce its own mine timbers to conserve the coal below. This company
claims to have lost but one life in ten years, and to save seventy-five
per cent. of its coal. This is a striking illustration of what better
mining methods will do for both the miner and the mine owner and of how
forestry may be an aid to the conservation of coal and also of human
life in the mines.

We have already shown how half of the coal is wasted, but there still
remains another source of waste at the mines. This is a large but
unknown quantity. Coal usually exists in beds or layers with shale or
rock between, much as a "layer-cake" is made, the layers of cake being
represented by the coal and the icing between by these "rock-partings,"
as they are called. In rich fields, there are from three to ten of these
rich layers or beds of coal, one above another. It often happens that
the thickest and best layer is the lowest, and when this is the case, it
is usually mined first, regardless of the fact that some, and possibly
all, of the higher beds are dislocated and broken or filled with deadly
gases. Nearly all this loss could be avoided by simply mining the upper
stratum first.

So much for waste at the mines. This is serious enough if it were all,
but it is not all, it is only the beginning. Let us see now what becomes
of the coal that is marketed. The railroads are the largest single users
of coal, and here we are confronted with the surprising statement that
our locomotives consume three tons of coal in doing the same work that
is performed by English locomotives with one ton. This difference is
said to be due to different construction of the engines themselves, and
to more careful stoking, or firing. Our locomotives use 100,000,000 tons
per