Abstract: Large-scale mined-out area are formed in molybdenum mine of Wudaoling due to disorderly exploitation, 3 times of large-scale ground pressure activities are caused one after another, and a great number of pillars were broken. Due to the geometric shape situation of complicated mined-out area, the three dimensional numerical model of mine left behind mined-out area was established. Numerical simulation was done on distribution of stress, displacement and plastic zone of upper mined-out area and isolation strip by MIDAS. The numerical results indicate that the large-scale mined-out area in molybdenum mine of Wudaoling must be filled, otherwise, instability and resurrection phenomenon is extreme possible appear.

Key words: Key words: Molybdenum mine, Mined-out area, Surrounding rock stability, Numerical simulation