Abstract: The final slope angle of Jinxin open-pit molybdenum mine of Chifeng Jingxin Mining Co., Ltd.of Sinosteel Corporation is determined by numerical simulation.If the final slope angle was too smaller, the amount of rock mass to be removed was too large, so the mine had been running at a very low efficiency.The 2D finite element elasto-plastic program (PHASE2) was used to determine the final slope angle, and the application of 2D limit equilibrium method to determine the final slope stability coefficient.The numerical results show that the final slope angle of upper plate should not be beyond 48°, and that of the lower plate should not be beyond 50°, and their average stability coefficients are 2.99, 3.49, respectively.It proves that the method is simple, intuitive, fast and reliable.

Key words: Mining safety, Open-pit mining, Final sloping angle, Numerical simulation