METHOD OF SLOPING HIGH BENCHES ON OPENCAST LIMITING CONTOUR Russian patent published in 2002 - IPC

FIELD: mining industry; applicable in sloping of high benches in opencast mining of kimberlite deposits. SUBSTANCE: method includes drilling of holes of contourside row to height of at least one working subbench at a distance of at least 14 hole diameters from design contour, then drilling of contour row holes in plane of formed high bench through its entire height, and the second row holes in each working subbench. Holes are charged with explosives and blasted, and broken rocks are withdrawn. First, loaded with charges and blasted are holes of contourside row, then the second row holes of upper working subbench, contour holes and the second row holes in each underlying working subbench. In this case, contour row holes are charged in lower part for height of underlying working subbench with charge density of 1-2 kg per meter run, and in upper part, they are charged with circular gap between charges and charge density of 4-8 kg per meter run. Broken rocks are withdrawn, first, from upper working subbench, then from contour zone and, at last from each underlying working subbench. EFFECT: increased stability of high benches due to reduced formation of fractures in rock mass behind contour and formation relatively smooth surface of bench slope. 3 dwg