METHOD OF ROCKS WORKING IN OPENCAST RECONSTRUCTION Russian patent published in 2002 - IPC

FIELD: mining, opencast mining; applicable in resuming operation of opencast nonmining flanks. SUBSTANCE: method includes working of benches by pillar splits and marginal stopes; hole drilling with in marginal stope; charging of holes with explosives and their blasting; leading working of marginal stope relative to pillar split; holes drilling in rock mass of pillar split, their charging and breaking pillar split rocks towards marginal stope. Width of pillar split is determined by relation B=(1.5-3)W, B > a, where B is width of pillar split, m; W is value of resistance of charge foot in marginal stope, m; a is width of prism of possible caving of bench slope, m. Drilled in pillar split rock mass is a row of inclined holes whose angle of inclination is taken in compliance with condition α≥ϕ, where α - is angle of hole inclination of pillar split, deg; ϕ - is angle of internal friction of worked rocks, deg. Holes are inclined towards marginal stope. Inclined holes of pillar split charges are blasted simultaneously with hole charges of marginal stope of underlying horizon, and muck is withdrawn. In easily blasted rocks, width of pillar split is taken equal to B=(2-3)W, and in medium and difficultly blasted rocks B=(1-2)W. EFFECT: higher productivity of stoping operations and safety of operations. 2 cl, 2 dwg, 1 ex