Underground mining

Underground mining extracts mineral deposits through shafts, tunnels, and other workings below the surface. It reaches deposits that are too deep or otherwise unsuitable for surface mining.

Shaft mining: Mining that reaches underground deposits through a deep vertical or steeply inclined passage. Shafts provide access to deep deposits and connect underground workings with the surface.
Orebody: A naturally occurring concentration of minerals that can be mined economically under specified conditions. Its size, shape, and orientation constrain the placement of shafts, tunnels, and stopes.
Coal mining: The extraction of coal from surface or underground deposits. Coal seams are commonly mined underground using room-and-pillar or longwall methods.
Acid mine drainage: Acidic, metal-bearing water formed when sulfide minerals react with oxygen and water. Mine workings can expose sulfide-bearing rock to conditions that generate persistent contaminated drainage.
Surface mining: The extraction of minerals by removing soil and rock above a deposit. Surface mining is generally favored when deposits lie close enough to the surface for economical stripping.
Drift mining: Mining that follows a horizontal or gently sloping passage into a deposit, often from a hillside. A drift can reach an orebody without a vertical shaft when terrain and geology permit.
Stope: An underground excavation from which ore has been removed, usually in a hard-rock mine. Stopes are the principal production spaces in many underground metal mines.
Hard-rock mining: The extraction of metallic ores and other valuable minerals from competent rock. Many deep metal deposits require tunnels and stopes cut through hard host rock.
Mine subsidence: The sinking or collapse of ground above underground excavations. Removal of underground support can deform the surface and damage buildings or infrastructure.
Open-pit mining: A surface mining method that extracts deposits from a large terraced excavation. Its broad, descending pit contrasts with the narrow access network of underground mines.

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