FIELD: mining industry. SUBSTANCE: according to method, drilled in roof of lower and middle layers over longwall are relief blast-holes and their height does not exceed thickness of layer being extracted. Distance in dipping between blast-holes is not over width of power support sections. Distance between rows of blast-holes along strike is not over half of pitch of immediate roof dipping. Angle of blast-hole incline towards rock mass is assumed as equal to 90 deg. between blast-hole line and line which forms expected caving dome of overlying rock. EFFECT: high efficiency. 3 dwg
