Abstract: The rock mass strength parameters of mining slopes are key indicators for the slope stability analysis and the mining design. The commonly used methods for estimating the rock mass strength indexes include the H-B, Feynko, and Georgi methods. This paper compares and analyzes the estimation results of the rock mass strength parameters obtained by various methods. The back analysis method is used to verify the estimation results from different theories. The rock mass strength parameters for the cohesion and the friction angles, obtained from H-B method, are 460 kPa and 27 °, respectively. The cohesion obtained by the Feynko method is close to that obtained by the H-B method, while the cohesion obtained by the Geggi method is relatively low. The cohesion and friction angle, from the back analysis method, are 450kPa and 27 °, respectively. The results indicate that the H-B method is the most reliable one. The friction angle of the rock mass can be obtained by reducing the friction angle of the rock blocks, by considering the integrity and the softening of the rock mass. Based on the stability estimation results, it is suggested that the slope angle of the studied mine steps should not exceed 60 °. The research results can provide a basis for the stability analysis and the mining design of mining slopes.

Key words: Open-Pit Mine, Rock Mass, Strength Parameters