Drift mining is either the mining of an ore deposit by underground methods, or the working of coal seams accessed by adits driven into the surface outcrop of the coal bed. A drift mine is an underground mine in which the entry or access is above water level and generally on the slope of a hill, driven horizontally into the ore seam.
Coal miner standing in a drift portal at Fork Mountain, Tennessee, 1920.
Drift mine entry in West Virginia, 1908. Photo by Lewis Hine.
Underground hard-rock mining
Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the same techniques used to excavate ores of gems, such as diamonds and rubies. Soft-rock mining refers to the excavation of softer minerals, such as salt, coal, and oil sands.
A 3D diagram of a modern underground mine with shaft access
Decline portal
Door for directing ventilation in an old lead mine. The ore hopper at the front is not part of the ventilation.