Coal and the coal mines

by Homer Greene

This concentration of coal lands and coal mining in the hands of great corporations, aside from its tendency to stifle healthy competition, is productive of many benefits. Coal can be mined much cheaper when the mining is done on a large scale. This is the rule, indeed, in all productive industries. An enterprise backed by the combined capital of many individuals is more certain to become successful and permanent than an enterprise inaugurated by, and carried on with, the entire capital of a single individual. Especially is this the rule in a business attended with as much risk as is the business of coal mining. One person may put his entire fortune of two or three hundred thousand dollars into a single colliery. A depression in the coal trade, a strike among the miners, an explosion, or a fire would be very apt to bring financial ruin on him. A company, with its great resources and its elastic character, can meet and recover from an adverse incident of this kind with scarcely a perceptible shock to its business. It is simply one of the items of loss which it is prepared to cover with a larger item of profit. There is also the additional assurance that all work that is done will be well done. The most careful observations and calculations are made of the amount and quality of included coal in any tract of land before it is purchased, and the best surveyors are employed to mark out the boundary lines of lands. The services of the most skillful mining engineers are retained, at salaries which no individual operator could afford to pay. Their forces are well organized, their mining operations are conducted with system and economy, and they are able to keep abreast of the age in all inventions and appliances that insure greater facility in mining and manufacturing, and greater safety to the workmen. Their employees are paid promptly at stated periods, and the possibility of a workman losing his wages by reason of neglect or failure on the part of his employer is reduced to a minimum.

In general, it may be said that the control of the anthracite coal business by the great corporations, rather than by individual operators, is an undoubted benefit, not only to all the parties in direct interest, but to commerce and society as a whole. The only danger to be feared is from an abuse of the great powers to which these companies have attained; a danger which, thus far, has not seriously menaced the community.

CHAPTER VII.
THE WAY INTO THE MINES.

A wise coal operator never begins to open a mine for the purpose of taking out coal until he knows the character of the bed and the quality of the mineral. This knowledge can only be obtained by an exhaustive search for, and a careful examination of, all surface indications, and by drilling or boring holes down to and through the strata of coal. This is called “prospecting.” The examiner in a new field will first look for outcrops. He will follow up the valleys and inspect the ledges and the banks of streams. If he be so fortunate as to find an exposure of the coal seams, or of any one of them, he will measure its thickness, will calculate its dip and strike, and will follow its outcrop. He will also study and make careful note of the rock strata with which it is associated, for by this means he may be able to determine the probability of other seams lying above or below it. This examination of the rock strata he will make, whether coal is visible or not visible. It will be of much service to him. For instance, it is known that the great Baltimore vein in the Wyoming valley is usually overlaid by a coarse red sandstone. If the examiner finds rock of this character in that section, he has good reason to hope that coal lies beneath it. Under the lowest coal seam of the anthracite beds there is found, as a rule, a rock known as the conglomerate. If, therefore, the explorer finds an outcrop of conglomerate, he will know that, as a rule, he need not look for coal beyond it. This rock, coming to the surface on the westerly side of the Moosic range of mountains, marks the limit of the Lackawanna coal field toward the east. No one, having once studied the conglomerate rock, could mistake it for any other, though its composition is very simple. It is nothing more than white, water-worn quartz pebbles, held together by a firm, lead-colored cement. But it is a rock of unusual hardness and durability. It is proof against the erosive action of water, grows harder by exposure to the air, and has a consistency that approximates to that of iron. In the coal districts it is used largely for building purposes, where heavy walls and foundations are required. Experience has taught that there are no coal seams below the conglomerate, so that wherever this is found as a surface rock, or wherever it is pierced by the drill, it is usually unnecessary to explore below it. If no coal outcrop is found, the bed of a stream is searched for fragments of the mineral, and, if any are discovered, they are traced to their source. Coal is sometimes exposed where a tree has been uprooted by the wind, and pieces of it have been found in the soil thrown out at a groundhog’s burrow.

Wagon roads crossing the country may be scanned for traces of the “smut” or “blossom.” This is the decomposed outcrop, which has become mingled with the soil, and may be more readily distinguished in the bed of a traveled road than elsewhere. Other surface indications failing, the topographical features of this section of country should be studied. Wherever the coal seams come to the surface, being softer than the rock strata above and below them, they are disintegrated and eroded more rapidly by the action of the atmosphere and the elements. This wearing away of the exposed coal leaves the surface outline in the form of a bench or terrace, which follows the line of the outcrop. And this form is retained even with a thick deposit of soil over the edges of the strata. Small shafts may be sunk or tunnels driven through this thickness of earth, and the outcrop explored in this way. This process of examination is of more value in the bituminous than in the anthracite regions, since the bituminous coal, being soft, is more rapidly eroded, and the terrace formation resulting from such erosion is more distinct and certain. In these days, in the anthracite coal fields, there is hardly an area of any great extent in which mines have not been actually opened. These mines, therefore, in the facilities they afford for studying exposed strata and developed coal seams, offer the best means of acquiring knowledge concerning the coal beds of adjoining tracts. In a country where no surface indications of coal are found over a large area, it is hardly worth while to explore for it by boring. In the anthracite regions of Pennsylvania the limits of the coal beds are now so accurately defined that it is seldom necessary to bore for the purpose of testing the presence of coal. But it is always advisable, before opening a mine in a new field, to test the depth, dip, and quality of the coal and the character of the seams by sinking one or more bore holes. Surface measurements of a seam are, at best, very uncertain, as indications of its continuing character. The angle of dip may change radically before a depth of one hundred feet shall be reached. And coal undergoes so great deterioration by long exposure to the atmosphere that, in order to judge the quality of a coal bed, it is necessary to have a specimen fragment from it that has been hidden away in the rocks. Hence the necessity of boring.

Hand drills were generally used in the early days of prospecting, and a sand pump drew out the sludge or borings for examination. This was superseded by the spring pole method, which in turn gave way to the rope method in use in the oil regions, the borings in each case being carefully preserved for inspection. The diamond drill is the one now in common use in the coal regions. Its cutting end is in the form of a circle set with black, amorphous diamonds. It cuts an annular groove in the rock as it descends, forming a core, which is withdrawn with the drill, and which may be examined in vertical section. The sludge is washed out by a stream of water which passes down through the centre of the drill rod, and is forced back to the surface between the rod and the face of the bore hole. The invention of this rotary cutting drill is due to Leschot of Geneva, and the method of flushing the hole to Flauvelle.

After having obtained all possible information concerning his coal property, and, if he be wise, embodying it in the form of maps, the coal operator must decide where he shall make an opening for mining purposes, and what kind of an opening he shall make. The answers to these two questions are, to a certain extent, dependent on each other, as certain kinds of openings must be located at certain places. When coal was first gathered for experiment or observation, it was taken up loosely from the ground, where it had fallen or been broken down from the outcrop of some seam. As it came into demand for practical purposes, it was quarried from this outcrop backward and downward, as stones for building purposes are now quarried, the seam being uncovered as the work proceeded. This process was followed along the line of the outcrop, but excavations were not made to any considerable depth, owing to the great expense of uncovering the coal.

The open quarry system of mining coal has been successfully practiced in America in but a few places. One of these was the great Summit Hill open mine, near Mauch Chunk, where the Lehigh coal was first discovered. Here, on a hill-top, was a horizontal coal bed, some sixty acres in extent, and varying in thickness from fifteen to fifty feet. Over this was a covering of rock, slate, and earth from three to fifteen feet in thickness. This bed was mined by simply removing the covering and taking the coal out as from a quarry. Other examples of this method are seen at Hollywood Colliery, and at Hazleton No. 6 Colliery, both near Hazleton, in Luzerne County. There are isolated instances of this method of stripping elsewhere in the anthracite regions, but as a rule the conditions are not favorable for it. Ordinarily there are four methods of making an entrance into a mine for the purpose of taking out coal. These are known as the drift, the tunnel, the slope, and the shaft.