Abstract: In the south of Shunda open-pit mine, there is a steep joint rock slope, which has potential safety hazard. Used preferred index method to determine advantage slip surface, the stability factor of slope was calculated. Reliability evaluation was done on stability and safety factor using instability probability analysis method. On the other hand, sensitivity analysis was done on internal friction angle and cohesion of coal and sandstone by using single variable method. The result indicates that the overall stability of the design slope was fine, but lower than the designed safety factor, the overall stability probability was 73% (Fs≤1.1). Internal friction angle of sandstone has greater impact on stability of slope. It suggests that interception and drainage measures should be noted during the project to prevent reduction of shear strength of the rock and soil caused by rainwater infiltration.

Key words: Open-pit mine, Slope, Preferred index method, Stability analysis