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water, which, furrowing the surface, have caused the gentle slopes of plains and hills. *
It results from the preceding remarks, that the slopes of the surface are not necessarily in conformity with the inclination of the beds; or, at least, that the irregularities of the actual surface should be the result of the inclinations and faults of the coal strata, is a very rare circumstance. Thus, to indicate or determine the bearing of seams in conformity to the unevenness of the surface, and its external configuration, is a useless speculation; and the opinion of miners, who having discovered an accidental parallel. ism between the inclination of the slopes of valleys and the seams of coal, have thence inferred a general rule, is erroneous to such a degree, that the exceptions are probably more numerous than the cases to which the rule applies. It often happens, if one regards the bearing of seams in a general manner, that their direction is parallel to the great axis of the basins, and this axis is confound. ed with that of the valleys. 37. Origin of the water encountered by the miner when pene
trating the earth. At different depths beneath the surface the miner meets with water in greater or less quantities, according to the disposition of the layers and the structure of the strata. It is now well proved, although a different opinion was at one time entertained, that all comes from the surface, where it has been absorbed by the differ. ent strata cropping beneath the vegetable soil. The rains which do not flow off to form streams and rivers, are infiltrated through the beds of the strata, the pores, joints, and fissures of which they traverse, descending until they meet a strata which is devoid of the properties of filtration, where they are arrested and retained. If the plane of a stratification of a bed is such that its lowest part outcrops upon the side of a hill, or if it is entirely above the bottom of a valley, the waters flow off naturally ; but if the impermeable bed folds and forms a basin, without an outlet, the water accumulates in a quantity dependent upon the porosity of the rock and the number and capacity of the fissures, thus forming simple internal springs, or vast sheets ready to drain into the shafts or other cavities which present a diminished lateral resistance. If, unfortunately, the layers which have been penetrated by an excavation have an outcrop in the bed of a little pond or
* It should be remembered that the superincumbent strata composed of rock of sufficient hardness to resist the action of the atmosphere, although they do not form actual mountains, yet present, always very elevated summits, having steep sides, and peaks even 150 to 200 feet in height. We find likewise the sur face of the carboniferou sstrata ragged and broken by trap and other volcanic matters, filling certain fissures, and elevated above the surface in consequence of the destruction of the rocks enclosing coal.
river, or rivulet, the copious and constant infiltrations bring into the mine great volumes of water, of which the miner is oftentimes unable to rid himself. All the considerations apply with equal force to the coal series and the stratifications incumbent upon them.
38. State of the waters in the chalk series. The dead grounds are dry, or carry water according to their position relative the bottom of the valleys, in which the surface is broken, that is to say, according as they are placed above or below the natural water level; the relative situation of the strata and the inflections to which they are often subjected, create oftentimes modifications in the general system that controls the waters.
The permeable beds of the chalk formations are traversed in every way by innumerable fissures, or straight cracks, which are horizontal or inclined, and communicating together and resembling in the mass, vast reservoirs, into which the rains settle. This water, unable to penetrate the dieves usually covering the coal strata where it collects, or to expand itself upon a horizontal ground, rises upward, and attains a level in the bottom of adjacent valleys, where it finds a free course. The upper portion can then be drained, but the lower is divided into as many cavities as there are fractured or permeable strata contained between the two beds of im. penetrable clay. This is the cause of the gushing up of artesian springs which the miner encounters in the midst of the layers of the chalk formation, and which rise in the excavations towards the surface of the ground. The springs contained in this strata are called niveaux. To penetrate these water-bearing layers and to restrain the water from entering the excavation, is called passing a niveau.
The abundance of the springs flowing in the cavities is a cause of the greater or less resistance they encounter in passing from one point to another; so likewise the number and the extent of the fractures containing them. Thus, where these are rare, slightly open, and such that they present serious obstacles to the circulation of the water, a simple windlass is sufficient to draw it off. But where the fractures are numerous, and extend a great distance, the collection of water is great, and its drainage at any one point is perceived in all the adjacent shafts. If, in short, any fissure open into a rivulet, the drainage becomes impracticable.
Fissures are very irregularly scattered in the mass of the chalk strata. We hear of cases in which the miner, after having long contended against the obstacles presented by the abundance of the springs, has abandoned his labor only to recommence it again at a short distance from the same spot, where the water being less in quantity has not prevented him from triumphing over every obstacle.
It might seem, at first view, that a coal formation completely
exposed, might be very advantageous, since the labor of exploring is simple and expensive, nor does the water present any obstacle to the openings required for obtaining the coal. Nevertheless, when the covering strata contain in their lower portion impermeable stratifications like the dieves, especially when they are not too thick or carry too much water, the difficulties of sinking are largely compensated by the advantage that the miner is protected from a large portion of the water at the base of the chalk series, during all the period of this operation, however long that may be.
39. Of the waters in the coal strata. The miner has no reason to apprehend in the coal strata any abundant springs, like those in the chalk formation. The beds of schist and the seams of coal furnish some rare infiltrations, which appear under the form of little streams or droppings escaping from the pores of the rock. But the sandstone, usually much fractured, and the clefts of which are very open, offers a passage to the water, very difficult to restrain and costly to drain. In general, the rule, or nature, of springs seems to be subject to one or the other of the following conditions; sometimes they dry up, after having been reduced by drainage, and do not appear again, or at least they do not show themselves again, except in very small quantity and at periods noted for heavy rains; sometimes they continue to discharge water with great uniformity; when such is the case, it is caused by some fissure operating as a canal from a great reservoir to the shaft, and furnishing the constant supply. In short, the waters of mines are generally more abundant the nearer the working approaches the surface, because the nearer they are to their source, so much less are the obstacles encountered by them in passing through the fissures of the strata.*
To be continued.
* A series of chapters more immediately follows in the works of Ponson which are devoted to descriptions of the coal basins of Belgium, France, England, and Germany. As these are particalars not of immediate interest to the practical miner in this country, we propose to pass over them for the present, and commence next with “ The method of searching for coal.”—ED.
COALS AND COLLIERIES.
ANTHRACITE COAL TRADE FOR 1856. Shipments by Reading Railroad to August 21st,
1,878,589 03 tons.
LEHIGH COAL TRADE TO AUGUST 16, BY CANAL. Summit Mines,
172,672 07 tons. Room Run Mines,
37,075 04 East Lehigh Mines,
17,152 03 A. Lathrop's Pea Coal,
1,197 07 Spring Mountain Mines,
56,742 12 East Sugar Loaf Mines,
41,680 15 Colerain,
40,813 05 Stafford,
8,123 16 N. Y. Lehigh Coal Co.,
22,994 15 German Pennsylvania Coal Co.,
14,444 08 South Spring Mountain Ridge,
10,474 10 Hazleton Coal Co.,
71,179 07 Cranberry Mines, .
40,308 13 Diamond Mines,
23,888 11 Council Ridge,
25,226 10 Buck Mountain Co.,
56,508 16 Wilkesbarre Coal Co.,
14,593 18 Wyoming Coal,
5,606 06 Hartford Coal Co.,
4,015 03 Total,
664,143 01 Lehigh Valley Railroad. Wm. Milnes & Co.,
61,259 15 tone. Rateliff & Johnsons,
2,238 08 Packer, Carter & Co.,
16,903 14 N. Y. & Lebigh,
6,590 11 Sharpe, Leisenring & Co.,'
3,312 14 German Penna, Coal Co.,
2,437 12 Total,
$2,742 14 By Canal,
664,143 01 Total for the week,
746,885 15 Same time last year, (Canal)
729,068 09 Increase in 1856, so far,
17,822 06 The decrease by Canal is
64,920 00 Delaware and Iudson Co.'s Coal Trade. For the last week,
271,01 tons. To same time last year,
882,049 Decrease so far,
812,186 tons, 801,339
Pennsylvania Coal Co.'s Coal Trade.
Increase so far, 2
Scranton Coal Trade for June.
7,443 17 tons, 18,212 19 20,656 16
The Scranton coal trade east towards New York, for July and to August 23d, will exceed 25,000 tons.
OUMBERLAND COAL TRADE.
Total shipped by each company from Januaray 1st to August 23d.
126,955.14 Percy & Co.
6,912.13 Aetna Coal Co.
7,521.14 Frostburg Coal Co. Borden Mining Co. Allegany Mining Co.
106,066.00 Carbon Hill Coal Co. Wellersburg Coal Co.
George's Creek Coal Co.
60,084.03 26,100.13 35,564.16 18,699.07 16,309.05 19,316.07
INOREASE OF ANTHRAOITE TRADE.
The increase of anthracite thrown into the market for the last five years reached 3,196,443, tons; 5 divided into this, would give the annual increase 630,286 tons. During two of these five years, the markets were completely cleaned out of coal, and prices ruled very high. For the last five years the increase of bituminous and semi-anthracite, including the foreign importations, destined for the Atlantic markets, reached 601,538 tons, which divided by 5 gives the annual increase at 188,307 tons.-Pottsville Jour.
COAL WHARVES AT TRENTON, N. J.
The method of unloading cars of coal by shutes into vessels is adopted in many places, varying only in such details as arise from local peculiarities. Those of our readers who have never witnessed this operation, will find the following sketch of the wharves at Trenton, of interest.
The Belvidere, Delaware Railroad crosses the Delaware and Raritan Canal, in the outskirts of the city of Trenton by a drawbridge, and curving towards New York, reaches the coal wharves with three tracks about half a mile.
A basin is dug or obtained by widening on the berne side of the canal. This basin is now 1,200 feet long, is well wharfed in front, and wide enough for a light schooner to turn around clear of one that may be loading at the time.
The landing to receive the loaded coal cars consists of a heavy and well braced trestling parallel with the canal, and carrying mainly three tracks of rails—the deck of the landing being elevated 17 feet above water line, which being in a canal level, has the advantage of being invariable.
The play of the landing is the continuous packet system (with some stretches of flat floor dumping gronnd). The trestles, are 12 feet apart centres, and between each pair is a sloping pocket crossing three tracks, and open to dumpage from each. All these pockets terminate below in a schute with a wrought iron apron, managed by a winch on deck, and proceeded by a cast-iron screen, exactly like the Navigation Landings at Port Carbon, in the dirt-separating arrangement. From these pockets, the coal flows by gravity, into vessels.
Each pocket is estimated to contain about 50 tons of coal (or 400 tons