Longwall mining

  An automated form of underground coal mining characterized by high recovery and extraction rates, feasible only in relatively flat-lying, thick, and uniform coalbeds. A high-powered cutting machine is passed across the exposed face of coal, shearing away broken coal, which is continuously hauled away by a floor-level conveyor system. Longwall mining extracts all machine-minable coal between the floor and ceiling within a contiguous block of coal, known as a panel, leaving no support pillars within the panel area. Panel dimensions vary over time and with mining conditions but currently average about 900 feet wide (coal face width) and more than 8,000 feet long (the minable extent of the panel, measured indirection of mining). Longwall mining is done under movable roof supports that are advanced as the bed is cut. The roof in the mined-out area is allowed to fall as the mining advances.
  U.S. Dept. of Energy, Energy Information Administration's Energy Glossary

Energy terms . 2014.

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  • Longwall mining — is a form of underground coal mining where a long wall (typically about 250 400 m long) of coal is mined in a single slice (typically 1 2 m thick). The longwall panel (the block of coal that is being mined) is typically 3 4 km long and 250 400 m… …   Wikipedia

  • longwall mining — /lɒŋwɔl ˈmaɪnɪŋ/ (say longwawl muyning) noun the system by which coal is extracted from a long continuous face …   Australian English dictionary

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  • longwall — /lawng wawl , long /, adj. Mining. 1. noting or pertaining to a means of extracting coal or other minerals in an underground mine from a continuous face, the roof before the face being supported at intervals by temporary or movable artificial… …   Useful english dictionary

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  • longwall system — ˈ ̷ ̷ˌ ̷ ̷ noun Etymology: longwall from long (I) + wall : a method of coal mining in which the working face extends entirely across the seam, the work proceeds either away from or toward the main shaft, and the roof is allowed to cave in behind… …   Useful english dictionary

  • longwall — /lawng wawl , long /, adj. Mining. 1. noting or pertaining to a means of extracting coal or other minerals in an underground mine from a continuous face, the roof before the face being supported at intervals by temporary or movable artificial… …   Universalium

  • coal mining — Coal was very important in the economic development of Britain. It was used as fuel in the factories built during the Industrial Revolution and continued to be important until the 1980s. The main coalfields are in north east England, the north… …   Universalium

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