METHOD FOR PRESERVATION OF EARTH SURFACE AT UNDERGROUND MINING OF COAL Russian patent published in 1999 - IPC

FIELD: mining industry. SUBSTANCE: this also relates to environment control. According to method, bore-holes are drilled from ground surface at angle which is equal to angle of displacement of underlying rock materials and over length of 10-20 m. Drilled bore-holes are located in staggered order at distance from each other which is equal to dimension of zone of active shifting of earth surface. After that, underlying rock materials are stabilized by injecting appropriate solution into drilled bore-holes. Application of aforesaid method reduces lowering of earth surface and ensures preservation of its soil together with saving ground surface structures. EFFECT: higher efficiency. 2 dwg