OUTSIDE FIXTURES AT MINES.
At all mines, where large amounts of material are handled, elevation is required for the purpose of transshipment or preparation. At coal-mines, and anthracite mines in particular, considerable elevation is required, in order that the coal may pass through the processes of breaking, cleaning, and separation without handling. This is a great item in the economy of mining. All handling of coal by manual labor should be avoided as far as practicable. We do not think there can be any case in which coal need be handled more than once, and that is by the miners when it is first excavated in the breasts. There are a few instances in which even this handling is not required: as, where the coal is worked by the mode known as the "run." But generally the coal must be handled once. It is thrown by hand into the mine-cars, when those cars go into the breasts in flat seams, and from thence passes direct to the "breaker." If the top of the drift, tunnel, slope, or shaft be as high as the top of the breaker, no more elevation is required; but if below, the cars are elevated by machinery to the proper height, and the cars are emptied or "dumped" in the upper, or receiving, shutes or bins of the breaker. From this point the coal descends by gravity through the breaking-rolls and the screens to the bins which contain the prepared coal; from thence it is drawn into the railroad-cars for shipment to market. In the process of passing through the breaking and cleaning machinery, great care should be taken to separate the slate and bone from the coal, which must be done by hand; and on the care with which this is done depends the purity of the marketable coal. It is true
that a great difference exists in the purity and cleanliness of coal as it comes from the mine, since some seams contain much more slate and bone than others, as may be noticed in our sections of coal, and even the same seam frequently varies in this respect. But all coal contains more or less of these impurities, generally in the body of the seam itself, but often from the top or bottom slate. It is, therefore, of the greatest importance that provision should be made in all coal-preparing establishments for picking out the slate and bone. This must be done ; and the economy and thorough ness with which it is done depend as much on the means provided as on the care which is taken.
A great many boys are usually employed for this purpose, and, unless under the care of a steady and sensible man, they are not as industrious and watchful as the case requires. In winter, during cold days, the little "slate-pickers" have a hard time gene rally, and but little can be done as our breakers are generally arranged. Stoves are sometimes used ; but these are not only dangerous, but far from effective, since the boys must go to the stove frequently in order to keep warm. The best plan is to warm the "slate-pickers' " apartment by means of steam-pipes. A few gas-pipes passed near the boys are the most effective for the conveyance of steam.