Abstract
For many years, the lead-zinc mine of Suichang Gold Mine has been mined by the segmented open-field method, and the mining above 500 m has been basically completed, forming a high-stage and large-span columnar goaf group, which is very easy to produce roof fall, slope fragmentation and instability collapse, and then leading to large-scale ground pressure disasters, causing surface subsidence and collapse, and endangering the safety of mining operations of deep untouched ore bodies. In order to better discuss the stability of the goaf, Flac3D is used for numerical simulation through field investigation and indoor rock mechanics experiment to analyze the stability change of the upper goaf before and after filling and its impact on the deep untouched orebody, and simulate the stability of the deep untouched orebody after the goaf is mined out and whether the hidden danger of safety can be eliminated after filling. Discuss the necessity of filling the levels of 260m ~ 290m, 300m ~ 390m, 420m ~ 500m, and 528m ~ 610m, and optimize the mining sequence of deep untouched ore bodies. The results show that the level 260m ~ 290m, 300m ~ 390m, 420m ~ 500m, and 540m ~ 610m should be filled with cementitious filling with a cement-sand ratio of 1:20, and the level 528m ~ 540m should be filled with cementitious filling with a cement-sand ratio of 1:8. Finally, the process and laws of goaf destruction are analyzed through the chain theory of disaster.