In the section as above given, we have not represented a small roll on the southern outcrops, as developed at Bancroft's Pioneer Colliery, and referred to in a previous page. It is here insignificant, and evidently "dying out," or disappearing from the basin, and is not sufficiently developed to justify an accurate delineation.
The illustration we have given of the Locustdale basins, in figure 58, is in strict accordance with present developments, but does not strictly agree with the opinion of those who are practically familiar with the basin. In their opinion, the basin is much deeper than portrayed; and this opinion is based on sound principles,—the increasing angle of dip as the workings descend, and the angle of the strata in the centre of the basin, denoting that the dip of the veins is greater towards the centre of the basin than on its outcrops.
We have given the angles as now developed,-45° on the south dip, and 70° on the north dip; but the probability is that an average of 70° would approximate the general inclination. The basin, therefore, instead of .a thousand feet of perpendicular depth, is, in all probability, over 2000 feet vertical from the surface.
We find in this conformity one of the conditions of that depression and lateral contraction which we endeavored to illustrate in figure 6. It would be impossible for the immense mass of coal existing in this deep basin to have been created on angles of such great acuteness. The coal must have been forthed under far different circumstances. It is uniform in character and quality; while the veins are in their best workable dimensions.
Figure 59 illustrates the workable veins of this basin. They are all found "in place," and are consistent with the formations of other regions. The Buck Mountain vein, or B, is in good size and condition, and the Skid more, D, is also finely developed. This vein ranges from 7 to 12 feet in thickness, but its best or most productive and reliable thickness is 10 feet. The Mammoth here is only 25 feet thick, but is uniform and unusually free from impurities, as shown by figure 60. As before remarked, this great bed is generally most productive and reliable when within its medium dimensions, or from 20 to 35 feet in thickness. At Locustdale its conditions are extremely favorable, and the natural advantages offered have been made practically available by the skill and experience of the management.
The mode of mining known as the "run" is here adopted with much economy. The solid nature of the superincumbent strata, and the more immediate top slate, render this mode available here in an eminent degree, while the purity of the vein enables the miners to send to the surface the entire production. When the angle is over 40°, and the conditions are as favorable as at this locality, the mode known as the "run" is the most economical that can be practised. But when the angle is too low to permit the coal to descend the dip of the vein by its own gravity, or the top slate is "rotten," and falls with the coal, or when the coal itself—the vein—is impure, this mode cannot be made use of to advantage. In the first place, because the coal
will not "run ;" and, in the second, the impurities falling and mixing with the coal render the whole impure and unfit for market. We shall notice this mode more fully, in connection with other modes, under the head of Economical Mining; while a more extended notice of the Locustdale colliery and improvements will be found in the Appendix, as we consider them the most perfect and extensive mines in the anthracite regions.
Figure 60 illustrates the Mammoth in this locality, and is a general type of this great bed in the western portions of the Mahanoy region. It is, however, thicker, and perhaps equally pure, in the vicinity of Ashland and on the Locust Mountain Coal & Iron Company's property generally. The large and valuable estates owned by the Preston Coal & Improvement Company, the Locust Mountain Coal & Iron Com pany, the Brock estate, the Locustdale Coal Company, and the Black Diamond Coal & Iron Company, are among the most valuable coal properties in the anthra cite regions. They are located in the western end of the region; which, we think, is generally more reliable than the eastern end, though the veins are frequently larger in that direction, as noticed in several localities. But we cannot justly make comparisons, since the eastern section is less developed than the western, while the coals of each enjoy a high reputation for their fine appearance and excellent quality.
We have found much difficulty in obtaining data in relation to the colliery establishments, but think we are generally correct in the classification of names and pro ductions for 1864. The region is not naturally divided into districts, and the coal pursues no special avenue to market. There are four railroad lines leading from the Mahanoy region. The first, commencing at the western end, is by the Mine Hill & Schuylkill Haven Railroad and planes, which ascend and cross the Broad Mountain some distance below Ashland. The second line is the Mahanoy & Broad Mountain Railroad and planes, which ascend and cross the Broad Mountain some distance above Girardsville, and descend by way of Mill Creek and St. Clair. The third line penetrates to the eastern end of the basin from the direc tion of Tamaqua, through the Hossasock Mountain by tunnel. This line, the East Mahanoy, connects with the Catawissa a short distance above Tamaqua, and termi nates at or near Mahanoy City, a distance of thirteen miles.
These lines are now under the control and management of the Philadelphia & Reading Railroad Company, to whose line they are large feeders.
The fourth line is the Lehigh & Mahanoy, and extends from the Black Creek junction with the Beaver Meadow Railroad to Mount Carmel, via Shenandoah and Centre ville, with a branch to Mahanoy City. This line promises to be an important outlet, as it opens the market direct by rail to New York. This road is 40 miles in length, and has some 14 or 15 miles of connecting branches to the mines.