Complex goaf system at Shouyun Mine is assembled by two upper and lower levels and steep left and right two blocks, the roof cover of goaf system is shallow. The stability of the goaf system are analyzed and predicted by using FLAC 3D numerical simulation. The study shows that the state of crushing destruction limit is achieved at the two corners of roof plates, and gradually expands into a deep extension of the arch. The tensile stress distributes in the central roofs, but tensile failure will not occur; the displacement of surrounding rock at goaf system is bigger than that of other rocks, but the overall goaf system is stable. The goaf roof safe thickness is comprehensively determined by considering a variety of factors; The goaf system is treated by using fan-shaped deep holes blasting in upper treat tunnels and open deep holes compression blasting, an overlying rock protection layer of sublevel caving was formed by filling goaf areas with breakout rock; the safety of goaf handling and conversion of mining methods were organically integrated.
Mines of metal mineral resources in China have entered the transition period from open-pit to underground mining. To enhance the production of underground mining and improve the recovery rate of ore in the early stage, the ore nearby slope is generally mined by using of stope method; the produced goaf may bring serious problems to deep ore body mining in the transiting process of open pit to underground mining (Swift & Reddish 2002). In recent years, the study of mine goaf is increasingly deepened, and a lot of progress in the stability assessment, detection and engineering handle of the goaf has been made.
