METHOD OF IMPROVEMENT OF STABILITY OF DEEP OPENCASTS Russian patent published in 2000 - IPC

FIELD: mining, more specifically, methods of protection of nonmining flanks of opencasts from disintegration under effect of rock pressure; applicable in increase of stability of deep opencasts and vertical shafts in mining of kimberlite pipes under permafrost conditions. SUBSTANCE: method includes determination of value of tectonic forces in rocks mass and formation of relieving zones round opencast by breakage of rocks by blast at distance from its flank not less than radius of abutment pressure. Relieving zone is made in form of ring or ellipse round opencast and extended through entire depth of action of tectonic forces but not in excess of depth of disturbance of natural stress field, or within zone of peak of tectonic forces value. Relieving zone over ring contour or ellipse is made in form of arc opposite to direction of maximum tectonic forces. In so doing, degree of rock mass relief in circular relieving zone is set proportional to value of tectonic forces. Relieving zones are made similar to ellipse shape of tectonic forces round opencast whose value is determined in intact rock mass. EFFECT: higher efficiency of deposit mining due to increase of stability of opencast flanks. 10 cl, 4 dwg