contour mining

Contour mining is a surface mining technique used in hilly or rolling terrain where a coal seam outcrops. It involves removing the overburden to expose the coal and then creating a bench around the hillside. The removed overburden spoil was historically pushed down the hill but is now often transported to fill valleys or replaced on the working bench. If profitable, further cuts are made into the hillside. Auger mining is often used in conjunction with contour mining to extract remaining coal by drilling holes into the seam from the last contour cut. Strip mining, in general, is the removal of overburden to expose and extract a mineral seam, such as coal.123