Abstract: The drop between underground mining face of central area and open pit of southeast area is about 700 m in Gongchangling second mining area，and in -220 m level the stope face is expanded 200 m from central area to southeast area，so about 500 m ore body which locates in the convergence site of the two mining area can`t be mined for locating in movement range.By analyzing orebody that at the end of collapse pit occurrence conditions and hazards form of rock movement，only the side wall chipping of collapse pit hazards the safety of orebody that at the end of collapse pit mining，and based on the theory of critical granular column，a measure that filling the existing collapse pit with waste rock to control chipping is proposed.And developed a scheme that to dump rock along the axial direction and along collapse pit edge direction cooperatively to ensure safety.On this basis，the orebody that at the end of collapse pit can be be mined with open-pit mining method by expand the open pit of southeast area.

Key words: Large drop orebody, Orebody at the end of collapse pit, Critical granular column, Ground movement control, Waste rock filling