The very abundance of the supply has made us enormously wasteful in its exploitation, as we have been wasteful in the exploitation of our forests. Unlike the forests, coal once destroyed does not grow again. The most valuable of our coals are in the Appalachian bituminous fields that stretch from northern Pennsylvania to Alabama, and in which some of the best sections have already been gutted and abandoned. In our greedy grasp for wealth, we have left one ton of coal to waste underground for every ton we have brought to the surface. More than one hundred and fifty thousand miners have been drawn into the mines in excess of efficient requirements. Planless overexpansion of the industry has resulted in such irregular operation of plant and equipment that for more than a generation the miners have lost an average of ninety-three days in the working year of three hundred and eight days, and a needless overhead charge has been imposed upon the consumer which Mr. F. G. Tryon of the U. S. Geological Survey calculates at a million dollars for each working day. Planless exploitation has made the most basic of our basic industries the prey of technical inefficiency and social unrest, the extent of which we as a people ignored until they threatened national and international disaster at the crisis of the war. This trouble might have gone on some time longer undiagnosed if we had not met our first modern national emergency in 1917. Of necessity the weight of the military structure was added to the weight of the industrial civil structure and the combined load was more than the coal industry could bear. It bent and broke under it, and in order to prosecute the war, the government was forced to take hold of the formless inchoate thing and reshape it into a stable prop for the national need. As a first step it was necessary to find out what this great unwieldy coal industry was. Coal mines are systems of tunnels driven into the veins where they crop out along the slopes of hills, or from the foot of shafts sunk through the overlying strata. These tunnels run for miles underground. Secondary tunnels run from the main tunnel or heading into the rooms where the miners work. The surveyor's diagram of a mine looks like a crushed centipede. The getting of coal out of the mines, after it has been picked or blasted down by the miner, like its distribution after it is brought to the surface, is almost entirely a problem of transportation.