PROCESS OF EXPANSION OF BOREHOLE BY DRILLING FROM BELOW Russian patent published in 2001 - IPC

FIELD: mining industry. SUBSTANCE: invention makes it feasible to expand borehole from below from spaces inaccessible spaces. Reduction of energy consumption and raised productivity are achieved thanks to insertion of collapsed drilling tool incorporating units of vertical and horizontal saw cut, as minimum, from above-lying horizon ahead of exit to space below. Then unit of vertical saw cut is open in direction away from borehole axis, rotary movement and upward axial force are transmitted to it, core is cut, unit of vertical saw cut is drawn out of vertical saw cut of space of core, is closed and drilling tool is moved upward to point of match of unit of horizontal saw cut with upper boundary of core. After it cutting part of unit of horizontal saw cut is advanced, core is cut away and falls into space located beneath by gravity. Then unit of horizontal saw cut is closed and cycle is repeated. Process of fall of cut-away core is controlled with the aid of video camera with illuminator. EFFECT: reduced energy consumption and raised productivity. 1 cl, 4 dwg