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.