METHOD FOR DRIVING MINE WORKINGS Russian patent published in 1995 - IPC

FIELD: construction of mine workings. SUBSTANCE: method for driving mine workings includes drilling of snubber, slab, preperipheral and peripheral blastholes. Peripheral blastholes are drilled with inclination beyond design outline of working to depth equalling 0.3-0.6 of depth of slab and preperipheral blasthole. Angle of inclination of peripheral blastholes is determined from equation α = arctg (L/h_con+h_sh+(h_d.j/2)-a)), grad, where h_con is concrete layer thickness, m; h_sh is thickness of tunnel shield, m; h_d.j is width of drill jumbo, m; a is distance from mouths of peripheral blastholes and outline of mine working, m; L is distance from tunnel shield to breast, m. Bottom of preperipheral blastholes is located on the design outline of working. Placed in bottom parts of preperipheral blastholes are high explosives. EFFECT: higher efficiency. 2 dwg