Underground soft-rock mining is a group of underground mining techniques used to extract coal, oil shale, potash, and other minerals or geological materials from sedimentary ("soft") rocks. Because deposits in sedimentary rocks are commonly layered and relatively less hard, the mining methods used differ from those used to mine deposits in igneous or metamorphic rocks (see underground hard-rock mining). Underground mining techniques also differ greatly from those of surface mining.
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Underground soft-rock mining in the context of Longwall mining
Longwall mining is a form of underground coal mining where a long single face of coal, known as a panel, is mined with a continuous cut across its entirety. Seams utilizing longwall panels are (typically 4–20 ft (1.2–6.1 m) thick).The panel is typically 10,000–15,000 ft (3,000–4,600 m) long, but can be up to 20,000 ft (6,100 m) long and 1,000–1,500 ft (300–460 m) wide. The longwall method compares with shortwall, room-and-pillar, and several others.
View the full Wikipedia page for Longwall miningUnderground soft-rock mining in the context of Underground mining (hard rock)
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.
View the full Wikipedia page for Underground mining (hard rock)