Abstract: In view of the main orebody of Baixiangshan iron mine is located under Qingshan river.In order to guarantee the safe mining，the numerical simulation method is used to build model of the ore body，surrounding rocks and faults.Faults model is built with rock weakening method.The surface and the faults with large influence are meshed，and then the caving and filling on the model are made by the continuously inclined drift stoping method with tailings backfilling to analyze the situation of surface subsidence.Through analysis and calculation，the maximum settlement value at the central river with the X-coordinate 400m is determined to be 0.23 m.According to the simulation results，an approach for grouting reinforcement of faults in risks was proposed.Through the calculation，the maximum settlement value is reduced to 0.15 m.The results verify the feasibility and safety of mining methods and the safety effectiveness of the grouting reinforcement method.

Key words: Mining with backfill, Numerical simulation, Surface subsidence, Grouting reinforcement