METHOD FOR DEEPENING OPEN PIT IN MINING OF STEEPLY DIPPING ORE BODIES Russian patent published in 1997 - IPC

FIELD: mining industry. SUBSTANCE: method involves horizontal stripping of overburden rocks and mineral by drilling and blasting operations and method of preliminarily slot formation in bringing of flanks to their limit positions. In the course of deepening ore located beyond the open pit design contour, under open pit bottom and in flanks, is extracted at the last stage of mining due to change of parameters of lower part of the open pit. The specified above change is effected in accordance with each step of deepening the open pit and finding the corresponding values of stable angles of flank reclamation. After determination of new boundaries of open pit contour, open pit is finally worked to form flanks to their limit stable positions. Final working is accomplished with due consideration of the selected production process by formation of flank with use of slots which are produced by hole drilling at an angle equals to stable angle of slope, but not less than the angle of inclination of bedding by lower wall of ore deposit and not more than 90 deg by hanging wall. EFFECT: higher efficiency. 1 dwg, 1 tbl