_Pockets._ Receptacles at the lower ends of shutes, in breakers, from which coal is loaded into railway cars. _Post._ A wooden prop to support the roof in bituminous mines. _Prop._ A timber set at right angles to the seam, in anthracite mines, to support the roof. _Prospecting._ Searching for indications of coal on the surface, and testing coal seams from the surface. _Pump way._ That compartment of a shaft or slope down which the pump rods and pipes are extended. _Rib._ The side of an excavation as distinguished from the end or face. _Rob._ To mine coal from the pillars after the breasts are worked out. _Rock tunnel._ A tunnel driven through rock strata. _Rolls._ In breakers, heavy iron or steel cylinders set with teeth, used for breaking coal. _Roof._ The stratum immediately overlying a coal seam. The rock or coal overhead in any excavation. _Room._ Synonymous with breast or chamber; used in bituminous mines. _Safety lamp._ A lamp that can be carried into inflammable gases without igniting them. _Scraper._ A tool used for cleaning out bore holes in blasting. _Screen._ Any apparatus used for separating coal into different sizes; usually, the revolving cylinder of wire mesh in a breaker. _Seam._ A stratum of coal. _Separator._ A machine for picking slate. _Shaft._ A vertical entrance into a mine. _Sheave._ The wheel in the head-frame that supports the winding rope. _Shift._ The time during which a miner or laborer works continuously, alternating with some other similar period. _Shute._ A narrow passageway through which coal descends by gravity from the foot of the breast to the gangway; an inclined trough, in a breaker, down which coal slides by gravity. _Single entry._ One of the systems by which bituminous mines are entered. _Slack._ The dirt from bituminous coal. _Slate picker._ A boy who picks slate from coal. A machine used for the same purpose. _Slope._ An entrance to a mine driven down through an inclined coal seam. Inside slope: a passage in the mine driven down through the seam, by which to bring coal up from a lower level. _Slope carriage._ A platform on wheels on which cars are raised and lowered in steep slopes. _Smut._ See Blossom. _Split._ A branch of a ventilating air current. _Spread._ The bottom width of a slope, drift, tunnel, or gangway between the legs of the timbering. _Squeeze._ See Crush. _Squib._ A powder cracker used for igniting the cartridge in blasting. _Steamboat coal._ One of the regular sizes of prepared anthracite. _Stopping._ A wall built across an entrance or any passage to control the ventilating current. _Stove coal._ One of the regular sizes of prepared anthracite. _Strike._ The direction of a line drawn horizontally along any stratum. _Stripping._ Mining coal by first removing the surface down to the coal bed; open working. _Sump._ A basin in mines entered by a slope or shaft, in which the water of the mine is collected to be pumped out.