by an inclined plane (forming a continuation of the slope) built as an open trestle.

Some of the same objections that apply to the location of the winding engine within the breaker, apply also to the prevailing practice of erecting the breaker engine in the lower part of the breaker; but the large number of breakers destroyed by fire directly or indirectly traceable to the breaker engine-room, is effecting a rapid change in this particular. A considerable number of breakers are now run by belting or wire-rope transmission of power from an engine located some distance from the main structure; as shown by the plan of the Exeter Colliery plant, Atlas Sheet No. IV.

Yet this method of operating a breaker is open to objection on account of the almost complete separation of the engineer from the breaker hands. This objection could be removed by a system of signal wires leading from different portions of the breaker to an alarm-gong in the engine room, which would enable the breaker hands, in case of accident, to notify the engineer promptly to stop the machinery.

Head-houses are objectionable from their liability to destruction by fire, and for this reason, if for no other, unhoused head-frames are preferred when the breaker is not built over the shaft mouth. Iron, frames are of course more durable than timber structures, and are not quickly injured by a shaft fire; but on account of their relatively greater cost they have been erected at but few collieries.

It is certainly poor engineering practice to inclose an expensive winding engine in a frame structure. Engine rooms at large collieries newly opened are now usually built of brick or stone, and separated by at least ten feet from the boiler house.

The boiler houses commonly built are frame structures— often the rudest kind of a shed, built of slabs and waste boards; but quite respectable stone and brick housings are seen at some collieries. The character of the boiler house, aside from its inflammable nature, is a matter of small importance.

When the plant contains a winding engine, a breaker

winding engine, and a breaker engine, besides feed-water pumps and a mine pumping engine, it is evident that all of them can be most economically erected and operated in one structure; but as the presence of other machinery may divert the attention of the engineer in charge of the main winding engine from his duties, and the presence of other engines, and the increased number of signals from gongs, etc., may be the cause of more or less grave accidents, the winding engine is usually isolated from other machinery, either by placing it in a separate structure, or in a room not communicating with the room containing the other machinery.

The breaker engine, breaker hoisting engine, mine pumping engine, and feed-water pumps, may all be housed in one structure, except when the mine pump is of the directacting Bull pattern, as at the Exeter colliery, (see Atlas Sheet No. IV.)

When the topography of the ground permits the location of the breaker at a point low enough to bring the top of the breaker (the cradle dump) on a level with the mouth of the shaft, a considerable sum can be saved annually; but such an arrangement can rarely be effected, and when this is done, the breaker is commonly at a considerable distance-in one instance a mile and a half-from the coal opening.

In all cases the breaker is so located that a railroad track may be constructed, with ample grade sidings, and of sufficient fall to handle the cars by gravity.

While there are many reasons (already enumerated) why the breaker should be located at some distance from the shaft opening, the handling of the mine cars, and the impossibility of moving them both ways by gravity, make it desirable to reduce this to the least possible distance consistent with safety from fire, etc.

The loaded cars are commonly transported to the breaker on a track having sufficient fall to move the cars by gravity, and the empty cars are drawn back to the shaft by mules; but the grade is sometimes so slight that mules are required on both the loaded and empty tracks.

To reduce to a minimum the loss of heat and steam by radiation from the steam pipes, it is of course advisable to have the boilers located as near the engines as possible.

Where coal is as cheap as at an anthracite colliery, especially when buckwheat coal is burnt under the boilers, economy of fuel is not an important factor, but the water used throughout the anthracite regions is often of a miserable quality for boiler use, and it is especially desirable on this account to economize in the use of steam, and use as few boilers and as little water as possible.

Hence the economy of the arrangement shown by Atlas plate No. IV in which the boilers are placed between the two engine-houses, and the steam connections are correspondingly short.

By locating the base of the boilers a few feet below the average level of the surface, the coal-bins are filled by a car dumping the coal in bins directly in front of the fire boxes; the same object is accomplished by building the boiler-coal track on a tressel (near the boiler house) so that the coal may be dumped into shutes and run directly to the firing floor, in front of the boilers. This car brings the coal down from one of the buckwheat coal pockets in the breaker to the boiler coal-bins.

In the location of the winding engine with reference to the head-frame, important problems seldom occur. It is found necessary, first, to place the winding engine at a certain distance to give sufficient lead so that the rope will coil regularly on the drum with a minimum amount of friction; and second, not to increase the lead to such an extent that the rope will be subject to violent oscillations. This latter difficulty is sometimes overcome by placing bearing pulleys between the drum and the sheaves. Such pulleys run free on a shaft of sufficient length to allow them to travel laterally with the rope as it coils or uncoils from the drum.

When the fan is located directly over the airway it is subject to more danger from fire than when located a few feet away from the shaft mouth, but when fans are not placed directly over the up-cast they are generally placed so very close to it that the risk of damage by fire is almost as great.

The principal reason, however, for locating the fan on one side of the upcast is to permit the use of this latter for the pumps and pump rods, and also in some cases, as at the Pottsville big shafts, the Exeter second opening, etc., to allow this opening to be used as an occasional hoisting compartment.

Until within the last few years the culm or coal dirt, the bony coal picked from the coal in the breaker, and the slate and rock coming from the mine were all deposited together in one heap or series of heaps, but the possible utilization of the culm or fine coal, either by burning in fire-boxes constructed for this purpose, or by manufacture into artificial fuel has given to the culm as it lies in the banks a certain prospective value, and to enhance this value and reduce the future cost of utilizing this refuse, two or three distinct kinds of refuse heaps are now common.

The fine coal known as culm, coal dirt, dirt, etc., that passes through the buckwheat screen mesh (or when no buckwheat is made, through the pea coal screen mesh) together with all the fine stuff made in the pockets and larger screens and collected at the lip and telegraph screens, is collected in separate pockets in the breaker and finally deposited in a heap known as the culm-bank or dirt-dump.

The rock and slate coming from the mine is carried directly to a heap known as the rock-dump, and the bony and slate picked from the coal in the breaker after being collected in pockets in the breaker is dumped on the slate or bony coal-bank; but the rock and bony coal are not unfrequently stored in a common heap, and at some collieries the bony coal is all recrushed in pony rolls and passed into the smaller sizes of coal, in which case the rock-dump contains nothing but slate and rock, with some coal adhering to the lumps.

In determining the location of the rock and culm-dumps the topography of the surrounding area exercises a governing influence, but it is always advisable to avoid depositing this refuse over the outcrop of a workable seam. When these heaps catch fire there is more or less danger of the fire extending to the outcrop coal and into the mine.

These heaps increase rapidly in size and often become of almost unmanageable dimensions, occupying ground needed for other purposes. The land thus occupied is, however, seldom of any value for agricultural purposes, except in some parts of the Wyoming region.

At slope collieries opened on the edge of the basin, the ground generally falls away rapidly enough to give ample dumping space within a short distance from the opening, but in many cases this descent is utilized by building the breaker below the mouth of the opening, and the culm is taken out at the foot of the hill.

Under these circumstances and generally at shaft collieries, or at slope openings on comparatively low ground, dumping height is obtained by an inclined plane, usually known as a dirt-plane.

Page plates 49 and 50 give some conception of the size these heaps attain and the amount of ground some of them cover. I have estimated that there is enough of this material to cover ten square miles of ground forty feet deep, or almost enough to form a pyramid one mile square at the base and twelve hundred feet high.

When no dumping ground at a lower elevation than the breaker is available and a dirt-plane is necessary, this should be located as near the breaker as circumstances permit; but that it should not face the breaker or any other important structure that may be injured by cars breaking loose on the plane, is equally apparent.

When the coal is washed and a large quantity of culm is carried off by the water through a sluice or flume, the nearest creek or water course is often made the receptacle for this material, but as such channels seldom carry a sufficient quantity of water to sweep away this sediment the streams are quickly clogged up by it, and after a time strew it in a thick deposit over the lower portions of the valleys, giving rise to suits for damages, etc.; the construction of large settling pools is therefore often necessary.

A good example of a compact mining plant is shown by Page plate No. 11, which represents the location of the