SCIENTIFIC AND PRACTICAL MINING.
mining and practical mining may be said to be almost synonymous terms. But the application of science and the higher intelligences to the practical and experi mental part of mining has enabled the miner to penetrate two thousand feet into the bowels of the earth and dig up the mineral wealth hidden by Nature in those deep recesses. There were many difficulties to contend with, which the simple miner could not overcome with his strength or his experience, and which defied his utmost exer tions until Watts brought his steam-engine to raise the coal and pump the water from the accumulating depths. But fresh difficulties were constantly arising, which were met and overcome by Davy, Stephenson, Wood, and others, who brought science to their aid.
The engineer of to-day finds no more difficult task to encounter than the proper and judicious planning of deep mines. In the intricate formations of the Pennsylvania anthracite mines the instances of failure are more numerous than those of success.
Something more than simple civil engineering is required of the "engineer of mines." He must be geologist enough to comprehend the lithological structure of the measures he would penetrate, in order to approximate the cost of sinking and see justice done by and to the workmen. The form and undulations of the hidden beds of coal must be unfolded on paper, and the design of the mine-working should be mapped, before the coal is struck or even the shaft begun ; since it cannot be properly located until the undulations are approximately marked and the axis of formation determined. To effect the purposes of drainage and ventilation, the depth and character of the coal basin should be generally known. The principles of mechanics, hydrostatics, and pneumatics are brought into requisition in deep mining; and no one not conversant with those branches of science can successfully engineer and manage the great collieries which the future demands of the coal-trade will require in the deep basins of the anthracite regions.
The want of educated mining engineers—practically educated—is now seriously felt, though not appreciated. Waste surrounds us on all sides. Our coal-beds are so magni ficent and our coal-fields so extensive that the waste is not now noticed, though it cannot fail to be felt in the future. If we could see the millions of dollars annually wasted, instead of the tons of coal which are annually buried from view and part recovery, we should then begin to appreciate the want of skill and improvement, and the value of the engineering profession.
Under scientific mining we may include the application of the arts and sciences to all the practical operations of the mine,—the use of the steam-engine in place of the " pannier-women" who formerly carried the coal to the surface on their backs, and the application of heat or mechanical force to ventilate the mine.
In penetrating the earth 1000 feet, and excavating coal-beds from under immense mountains, whose weight we can scarcely estimate, something more than mere force is necessary. It is not merely the question of obtaining the coal, or of keeping up the moun tain, but one of profit and loss, that must be considered. An immense outlay of capital is first required; and, in order to return a reasonable interest on the same, the coal must be obtained as cheaply as it could be dug from open quarries, and the operation must con tinue for a long period in order to return the investment with the interest. Order and system must be maintained through many miles of under-ground roads and air-courses, notwithstanding the irregularities of the coal-seams and the unforeseen changes of dip, of size, and of coal. One thousand tons of coal per day, or 30,000 cubic feet may be dug from beneath the superincumbent mountains, and yet the hundreds of men must feel safe beneath the mighty mass. This vast quantity of coal must pass through the mine, —sometimes through miles of subterranean passages,—and be hauled to the surface. up the long ascent of a thousand feet, day after day, without intermission. At the same time, nearly 1,000,000 gallons of water must be made to flow up from this great depth to find its way to the sea, and over 100,000,000 feet of atmospheric air must be made to circulate through the dim avenues and workings of the extensive mine. All this must be done by scientific and mechanical means. There must be no bungling nor mistakes; for the lives of hundreds of human beings, and perhaps the saving of hundreds of thousands of dollars, depend on the labors of the engineer. If the coal is not dug almost as cheaply as the dirt or earth can be moved from the surface, and in large quan tities, the whole thing is a failure : fortune, time, labor, all are spent in vain. If the vast stream of water is not kept steadily flowing up the deep shaft, the mine and all below is flooded ; and if the air-currents are suspended only for a short time, the rapidly-accumulating gases endanger both life and property.