Abstract: Large area hanging arch formed by strong roof seam mining can usually cause serious damage to stope even the whole mine. Movement law of overlying strata under different conditions of support resistance and distance between hard rock bed and coal seam has been analysed by theoretical calculation and numerical simulation. The results show that when the overlying strata of coal seam directly is hard rock bed (distance between hard rock bed and coal seam is 0 m), the concentrated parameter of abutment pressure and the released energy from this system reaches the maximum, the rapture of hard rock bed easy to cause fully mechanized supports crushing accidents or impulsion pressure which constituted a great threat to safety production. Good effect has been gotten in the field application by using forced roof caving technology to process this roof type.

Key words: hard roof, forced roof caving, strata control, energy