LOCUSTDALE* COAL COMPANY.
The above transverse section represents the coal basins in the vicinity of Locust dale. The property owned by the Locustdale Coal Company extends from the centre of the deep left basin to, and inclusive of, the middle basins on the right of the Bear ridge, anticlinal. It will be noticed that all the important coal seams of the anthracite fields are here represented, from A, in the conglomerate, to and inclusive of H and I, or the Orchards, with an aggregate thickness of from 100 to 125 feet of available coal.
The position or conformation of these deep and extensive basins of coal are ex tremely favorable for mining operations, since all the coal on the property can be obtained, if desirable, through one slope, sunk—as the present one is on the Mam moth—by tunnels north and south. The south dip of the coal beds in the deep basin, on the left, range from to ; consequently the tunnel distance from seam to seam will be limited—the tunnel distance decreases as the dips increase and vice versa. It will also be noticed that the north dips of the seams are inverted in the middle basins and pitch in conformity, nearly, with the south dips ; this naturally decreases the tunnel distance from one basin to the other and renders the coal in the middle basin available to the present slope on the Mammoth.
The estate of the Locustdale Coal Company embraces 1243 acres of coal land, running east and west on the south and middle basins, as before described. The run" of the gangways on the seams may be nearly three miles—(that is, the " run" on the " strike" of the veins, in mining phrase)—and the plane of the coal, descending to the centre of the deep basin, is supposed to be from 2000 to 2400 feet in length, requiring six to eight lifts of 300 feet each, below water level, to reach the bottom of the basin. We may safely calculate that the company has one square mile, or 640 acres, of available coal on the plane or area of the seams in the deep basin alone, exclusive of a large amount in the middle basin.
At 100 feet thickness, this should yield, by careful mining, 150,000 tons per acre, or nearly 100,000,000 tons to the square mile. There is, therefore, ample room and an abundance of coal for several extensive collieries on this magnificent coal prop erty, the value of which cannot now be properly appreciated.
The accompanying vertical section illustrates the number, thickness and relative position of the coal-beds in the southern or deep basin. There are ten workable seams proved, two of these, I and H, or the Orchards, are red ash, and in all probability a portion of B, or the Buck moun tain, is also red-ash; while the seams below it are of that color, but the coal partakes of the white-ash variety in character and appearance. The primrose, or G, is known in this region as the " Mahanoy Vein ;" it is generally a fine white-ash bed, and is here in its best condition. The Holmes, or F, is here known as the " seven foot ;" a tunnel has been driven to it from the Mammoth, and is continued to the Mahanoy, G. The Mammoth itself, as shown by the section on the next page, is a splendid bed, twenty-five to thirty-five feet in thickness, almost pure coal ; and is, perhaps, more productive than this at many points, where it is found in excessive enlargements. The dip of this seam, its purity from slate, and the solid character of the " roof " or top slate, render it available to the most economical mode of mining that can be practiced—that known as " runs." In this mode, enough of the broken, or loose coal, remains in the "breast" to keep it full and the miners up to their work ; but as the excavated coal requires more than its original space, when in the solid, about one-half of the coal " cut" by the miners is drawn from the "breast," as the work progresses upwards. Thus, when the miners have finished their work in a breast, it will still remain full of coal, and six months or a year may be required to draw it ; since each breast contains 10,000 cubic yards of space, and produces about 10,000 tons of coal altogether. The advantages of this mode of mining are, economy in production, and regularity in work. The mine always contains ready coal enough to keep everything in active operation, though the miners may remain idle for months ; it was estimated, at one time, that from 80,000 to 100,000 tons of coal were mined in the breast ; there are, however, but few localities where this mode can be successfully made use of.