Technique for the surface mining of coal by removing the soil and rock overburden above a seam and extracting the exposed mineral.
The method is used to best advantage where the coal seam is thin and not deeply buried. (Thicker and deeper seams would be extracted by open-pit or underground mining.) Strip mining is most economical where flat terrain and horizontal seams permit a large area to be stripped. Where deposits occur in rolling or mountainous terrain, a contour method is used that creates a shelf with a slope on one side and an almost vertical wall on the other. A variety of equipment is used, including dozers, scrapers, hydraulic shovels, draglines, and bucket-wheel excavators. Concern over the environmental effects of strip mining have resulted in numerous requirements for the reclamation of excavated land.