Publisher's Synopsis
Coal is one of the world's most plentiful energy resources, and its use is likely to quadruple by 2020. Coal occurs in a wide range of forms and qualities; but there are two broad categories: Coal is mined using giant machines to remove the coal from the ground. There are two basic methods to remove coal: surface mining and underground mining. Surface mining is used when the coal is typically less than 200 feet below the surface. Giant machines are used to remove the top layers of soil and rock to expose the coal. The coal is excavated, and after the mining is complete, the soil and rock are returned to fill the mine. It is a general rule that technological factors dictate a clear choice between surface and underground mining, whereas economic and social factors determine whether a coal reserve will be mined at all. Some coal reserves, however, are surface-mined first and then deep-mined when the coal seam extends to such great depths that it becomes uneconomical to continue with surface mining. Contour mining is commonly practiced where a coal seam outcrops in rolling or hilly terrain. Basically, the method consists of removing the overburden above the coal seam and then, starting at the outcrop and proceeding along the hillside, creating a bench around the hill. In the past, the blasted overburden spoil was simply shoved down the hill; currently, soil is either carried down the mountain to fill a chosen valley in horizontal layers or is replaced on the working bench itself in places where coal has been removed. This 1st volume of Encyclopaedia of Coal Mining Methods presents comprehensive coverage through original research articles, new developments, case studies and critical reviews in all aspects of scientific and engineering research on coal, coal utilizations and coal mining. It focuses on key topics of coal scientific research and mining development, serving as a valuable resource for students and scientists to present research findings and discuss challenging issues.