METHOD FOR ROCK BLASTING IN OPEN PIT Russian patent published in 1995 - IPC

FIELD: ore mining industry. SUBSTANCE: drilled undercutting holes spaced at 200-500 m. Undercutting holes are drilled with inclination to undercut the level of bottom of breakage holes in the second or in the last row provided the difference in elevations of mouth and bottom of undercutting hole is within 7 m. In case of insufficient filtering capabilities of worked rock mass, blasting method is used to develop transverse and main drainage zones. After provision of transverse zone, arranged in undercutting hole is water conduit with its outlet on the slope of low bench to vessel. Hole mouth round the metal pipe is sealed with rubber ring. Water flows into vessel, first, under the water head from undercutting hole, and then, due to vacuum created by water between levels of vessel (metal pipe ring) and hole mouth. As a result, cone of influence in water flow in bench is provided and constantly maintained at the preset level that allows blasting of bench rocks with use of explosives not resistant to water. EFFECT: higher efficiency. 2 cl, 2 dwg