A probe into“mining technique in the condition of floor failure”for coal seam above longwall goafs

Targeting at the coal seam with useful value discarded above goafs,attempted to explore the feasibility of"mining technique in the condition of floor failure" from theoretical point of view,and predicted.It indicated that mining technique in the condition of floor failure used above Longwall Goafs in Baijiazhuang Mining is totally feasible.At law,the deformation of the floor in the mining technique by means of probability-integral method.And it is discov- ered that deformed basin can emerge in the footwall of No.6 coal seam and its maximum subsidence was possibly 1 633 mm or so and its maximum positive curvature is 61.74/10-3. At last,it therefore suggests appropriate ground pressure control measures as strengthening observation of ground pressure and adopting false slope for exploitation and strengthening support for reasonable push and slide based on the adverse ground pressure behaviors possibly occurring in the mining technique.This serves to gather data and lay sturdy founda- tion for further probe into the mining technique,and offers theoretical and technical grounds for concrete implementation of the mining technique.