Spoil Heap

a pile for stacking waste rock brought to the earth’s surface from mines and pits. At coal mines, as a rule, flat spoil heaps are built; conical, ridge, and sector spoil heaps are also known. Spoil heaps are classified according to the mode of transporting the waste rock; waste rock may be hauled by skip hoists, cableways, conveyors, trucks, rail transport, or hydraulic means. In order to minimize damage to the environment, spoil heaps are reclaimed in two stages—a construction stage that involves the leveling or grading of slopes and the placing of a fertile layer of soil on the surface and a biological stage that entails the sowing of grass and the planting of shrubs and trees.