METHOD FOR MINING OF THICK STEEP FIRE-HAZARDOUS COAL SEAMS Russian patent published in 1994 - IPC

FIELD: mining industry. SUBSTANCE: method consists in driving development workings, extraction of upper part of level by downcast layers with provision of hardening fill in worked out space, and mining of lower part of level with roof rock caving under protection of flexible roofing mounted in inclined mounting layer. Formation of stable artificial level pillar is performed by working upper part of level, first, with horizontal layers, and then, with transverse inclined layers of variable thickness with imparting angle of natural slope to caved roof rocks. Working of inclined mounting layer is carried out with breakage of roof rocks over entire height of level by blasting charges in long holes. EFFECT: higher efficiency. 2 cl, 8 dwg