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Underground Coal MiningLongwall Mining  This drawing depicts the longwall method of underground mining. Longwall mining now accounts for about 31% of underground coal production. There are over 100 longwall operations in the United States, most of them in mines in Appalachia. In longwall mining, a cutting head moves back and forth across a panel of coal about 800 feet in width and up to 7,000 feet in length. The cut coal falls onto a flexible conveyor for removal. Longwall mining is done under hydraulic roof supports (shields) that are advanced as the seam is cut. The roof in the mined out areas falls as the shields advance. |
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United Mine Workers |
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