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The most common method of extracting coal from mines are:

  • The most common method of surface mining is open pit mining. This technique is most appropriate for areas with flat terrain, exposing coal while removing soil above the coal layer in batch system. When all the soil above the coal layer is removed, the underlying coal block is exposed and can then be drilled and blown. This process is performed successively, block by block.
  • The contour mining method is the most commonly used surface mining technique in steep terrain areas. This method involves removing the soil above the charcoal layer in a standardized way, following the surroundings of a hill or a mountain, for example. This method requires great safety precautions, as it can cause large landslides and serious soil erosion problems. To solve these problems, a variety of methods have been developed over the years to establish limits for mining work.
  • The method of mountain mine clearance involves the removal of mountains to expose coal shafts, eliminating sterile areas from mining sites. This practice combines the technology of mining of surroundings with the one of mining in the open sky.

Answer:

coal companies literally remove the tops of mountains with dynamite and earth–moving machines, called draglines, in order to reach coal seams. The waste rock—the remains of the mountains—is piled into neighboring hollows in towering earthen dams called valley fills. The largest fills can approach 800 feet in height and swallow more than a mile of streambed.

Explanation:

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