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Services for mining
Mountaintop/Mountain-top/Mountain top removal mining (MTR), also known as mountaintop mining (MTM), is a form of surface mining that involves the mining of the summit or summit ridge of a mountain. Entire coal seams are removed from the top of a mountain, hill or ridge by removing the so-called overburden (soil,lying above the economically desired resource). After the coal is extracted, the removed material is put back onto the ridge to approximate the mountains original contours. Any overburden the mining company considers excess (that which its not able to place back onto the ridge top) is moved into neighboring valleys. Mountaintop removal is most closely associated with coal mining in the Appalachian Mountains in the eastern United States.
Peer-reviewed studies show that mountaintop mining has serious environmental impacts, including loss of biodiversity, that mitigation practices cannot successfully address. There are also adverse human health impacts which result from contact with affected streams or exposure to airborne toxins and dust
Mountaintop removal site.
Mountaintop Removal in Martin County, Kentucky Just under half of the electricity generated in the United States is produced by coal-fired power plants. MTR accounted for less than 5% of U.S. coal production as of 2001. In some regions, however, the percentage is higher, for example MTR provided 30% of the coal mined in West Virginia in 2006.
Historically in the U.S. the prevalent method of coal acquisition was underground mining which is very labor-intensive. In MTR, through the use of explosives and large machinery, more than two and a half times as much coal can be extracted per worker per hour than in traditional underground mines, thus greatly reducing the need for workers. In Kentucky, for example, the number of workers has declined over 60% from 1979 to 2006 (from 47,190 to 17,959 workers). The industry overall lost approximately 10,000 jobs from 1990 to 1997, as MTR and other more mechanized underground mining methods became more widely used. The coal industry asserts that surface mining techniques, such as mountaintop removal, are safer for miners than sending miners underground.
Proponents argue that in certain geologic areas, MTR and similar forms of surface mining allow the only access to thin seams of coal that traditional underground mining would not be able to mine. MTR is sometimes the most cost-effective method of extracting coal.
Several studies of the impact of restrictions to mountaintop removal were authored in 200 through 2005. Studies by Mark L. Burton, Michael J. Hicks and Cal Kent identified significant state level tax losses attributable to lower levels of mining (notably the studies did not examine potential environmental costs, which the authors acknowledge may outweigh commercial benefits).
US EPA diagram of mountaintop mining: "Step 1. Layers of rock and dirt above the coal (called overburden) are removed."
"Step 2. The upper seams of coal are removed with spoils placed in an adjacent valley."
"Step 3. Draglines excavate lower layers of coal with spoils placed in spoil piles."
"Step 4. Regrading begins as coal excavation continues."
"Step 5. Once coal removal is complete, final regrading takes place and the area is revegetated."
From Wikipedia, the free encyclopedia : Services for mining
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