Coal and the coal mines

by Homer Greene

The necessity which controls the form and construction of the breaker building is that the unbroken and unscreened coal must first be taken to a point in the building sufficiently high to allow of its passage, by gradual descent, with slow movement, through successive rolls, screens, shutes, and troughs until, thoroughly broken and fully cleaned and separated, it reaches the railroad cars, standing under the pockets, and is loaded into them for shipment. It is sometimes possible, as has already been intimated, to locate a breaker on the side of a hill so that the coal may be run into the head of it from the mine by a surface track without the necessity of hoisting. In this case the building will hug the hill, extending for a long distance down the slope of it, but without rising at any point to a great height from the surface of the ground. In these days, however, the breaker is more frequently erected in the valley. The general results are thought to be better, and the special convenience to railroad outlets to market is certainly greater. Besides this, the necessities of the case in shaft mining seem to demand it.

A peculiar and characteristic feature of a breaker so built is the great vertical height to which one portion of the building is run up. This is the portion that contains the shaft up which the coal is hoisted, and from the top of which it starts on its long descending route to the surface again. From one hundred to one hundred and fifty feet is not an unusual height for this portion of the building. From this topmost part of the structure the roof slopes down by stages, on one or two sides, widening out, running off at an angle to cover a wing, spreading by a projection here and there until, by the time the last ten feet in height are reached, the ground space covered by the building has come to be very great. Under the last or lowest portion of the structure are the railroad sidings on which the cars stand to be loaded from the many pockets in which the shutes have terminated. Two engines are necessary at the breaker, one a winding engine to hoist coal from the surface to the top of the breaker, and the other a breaker engine to move the rolls, screens, and other breaker machinery. The winding engine is usually put on the opposite side of the shaft tower from the rolls and screens, and the ropes from it, either exposed or under cover of a long sloping roof, reach up to the sheaves in the head frame. The breaker engine is usually housed in a wing at one side of the main building, while the several nests of boilers, under a separate cover, are required by the act of 1885 to be at least one hundred feet away from the breaker.

No one, having once seen and examined an anthracite coal breaker, could ever mistake one for a building erected for any other purpose. These breakers have a character peculiarly their own. They are the most prominent features in the landscape of every anthracite coal region, where they tower up black, majestic, many-winged, and many-windowed, in the range of almost every outlook.

When the mine car full of coal is hoisted to the head of the breaker it is run by two headmen from the carriage across the scale platform to the dump shute bars on to which it is dumped. These are long, sloping, parallel iron bars, set two and one half inches apart. The dirt and all the coal that is small enough falls through these bars into a hopper, from which it is fed into a pair of screens, one on each side. These separate the dirt in the manner already described, and divide the clean coal into sizes smaller than, and including, egg. Each size as it falls through the segment of, or out at the end of, the screen, is caught in a separate shute and carried to a second set of revolving screens where it is again cleaned and separated, passing from these screens into the picking shutes. All the shutes or troughs in which the coal is carried have a sufficient inclination to make the material move by gravity, and, to decrease the amount of friction, the bottom and sides of each shute are lined with sheet iron. The large coals which passed over the dump shute bars now slide down to a second set of bars, set four and one half inches apart, called steamboat bars; all coal falling through these being separated by still a third set of bars into steamboat and egg, and eventually finding its way to the picking shutes or to the rolls which break the prepared coal. All coal which passed over the steamboat bars is lump coal, and, after having the slate and bony coal removed from it by hand as it passes, is carried into the lump-coal shute and sent down to the loading place; or else it is carried, by another shute, into the heavy rolls and crushed. As it emerges, broken, from these rolls, it passes into revolving screens, and the same process of screening and separating goes on that has been already described in the case of coal falling through the first or dump-shute bars. But all this broken, screened, and separated coal finds its way eventually into the picking shutes. These are narrow troughs down which the separate grades of coal pass slowly in shallow streams. Across the top of each trough, at two or more points in its route through the picking-room, narrow seats are placed on which boys sit facing up the shute. These boys are called slate pickers. It is their duty to pick out the pieces of slate, stone, or bone, from the stream of coal which passes under them, and throw this refuse into a trough at the side of the shute, from which point it slides rapidly away. The coal as it comes from the mine is full of waste material, so that the boy who sits first or highest on the shute has no trouble in finding plenty to do, and, work as hard as he may, much of the unfit material must still escape him. The boy who sits below him on the shute is able to give the passing stream a closer inspection and more careful treatment, and, should there be one still below, he must have sharp eyes and skillful fingers to detect worthless pieces that have been left by his comrades. The boys often put their feet in the shute and dam the coal back for a moment to give them time to throw out the abundance of slate that they may see, but no matter how careful they are, nor how many hands the coal may pass through in the picking process, a certain percentage of slate and bone is sure to remain. The slate pickers are not all stationed in one room, though the picking-room usually holds the greater number of them. They are put at the shutes in any part of the breaker where their services may be useful or necessary. Indeed, there are pickers who sit at the refuse shutes to pick out the pieces of good coal which have been inadvertently thrown in by the other pickers. In some breakers the coal passes from the shute across a gently sloping platform, by the side of which the boy sits to pick out the waste.

SCREEN-ROOM IN BREAKER, SHOWING SCREEN AND SHUTES.

But the time is undoubtedly coming when the occupation of the picker boy will be gone. The inventive genius of the age has already devised machinery which does its work faster, better, and with greater certainty than the most conscientious breaker boy could hope to do it. The great collieries are, one by one, adopting the new methods, and the army of breaker boys is gradually but surely decreasing.

Nearly all the slate-picking machines are based on the fact that the specific gravity of coal is lighter than that of slate or stone. One method brings the principle of friction into play. A section, a few feet in length, of the floor of the shute down which the coal passes is made of stone. At the end of this stone section is a narrow slot cut in the floor, crosswise of the shute, and beyond the slot the iron bottom is continued as before. Now when the shallow stream of broken coal strikes the stone bottom the friction between that bottom and the pieces of slate and stone is so great that these particles are impeded in their progress, and by the time they reach the slot they have not impetus enough to cross it and must therefore drop into it and be carried away. But the friction between coal and stone is slight in comparison, and the pieces of coal retain enough of their impetus to carry them safely across the slot and on down the shute. This is not a perfect separation, and the coal and slate which it divides has usually to be looked over again, to insure satisfactory results. The best and most practicable invention thus far brought into use is that of Mr. Charles W. Ziegler, picker boss at the Von Storch colliery, Scranton. This machine acts somewhat upon the method last described, though by a system of rollers, levers, and screens in connection with it and attached to it, it is able to make quite perfect separation of the coal and slate. Two or three of these machines placed on a single shute should do the work required of them very thoroughly.

The experience of domestic buyers of coal would seem to indicate, either that the picker boys do not do their whole duty or that the picking machines have not yet been made perfect. But it must be remembered that the separation of slate and bony coal from good material is made only in a rough and general way in the mine, and that a very large percentage of the output, as it reaches the breaker, is unfit for use. To clean and separate this material thoroughly, therefore, requires much labor, and extreme care and skill.

After these separate streams of coal have passed the scrutiny of the picker boys or the test of the picking machine, the shutes in which they run are narrowed into pockets or bins, closed at the end by a gate. The pocket projects over the car track high enough from it for a railroad coal car to stand beneath, and the coal is then fed from the pocket into the car at will.