What is Longwall mining?

Longwall mining is a highly productive coal mining technique. Longwall mining machines consist of more rotten coal coal coal mounted on a number of self -rushing hydraulic ceilings. The whole process is mechanized. Longwall mining machines have about 800 feet (240 meters) in width and 5 to 10 feet (1.5 to 3 meters) high. Longwall miners extract "panels" - rectangular coal blocks as wide as mining machines and up to 12,000 feet (3,650 meters). The massive Shearers cut off the coal from the face of the wall that falls on the transport belt for removal. When the miner Longwall progresses along the panel, the roof behind the mining path can collapse.

Longwall mining was first introduced at the age of 50 and 60. Today it represents more than half of all coal production in the United States. On any given day, the Longwall mining system is able to extract between 10,000 and 30,000 tons (9 to 27 million kilograms) from the panel. Primary ANOwnside to this very productive technique is enemiesRock Initial Investments - Longwall mining machines usually take place between $ 5 and $ 15 million.

Longwall mining replaces the historic "room and post" method, while underground "rooms" of coal are manually extracted and the columns are left to support the roof so that miners can function safely. In the mining areas deeper than 1,000 feet (300 meters), the room and head method becomes highly uneconomical, because the size of the columns needed to support the roof is much larger, which means that they cannot be extracting of valuable charcoal. Longwall systems make deep mining.

Sometimes Longwall mining is called destructive or environmentally dangerous because it causes soil to fall above the mined panel. This can damage underground water tables, surface structures and can cause soil erosion. Careful geological surveys can help alleviate these problems. Since the technological pokThe year continues to increase Longwall miners, responsible for the growing part of the total coal production in the world.