Stability Analysis of Southern Slope of Chenmenshan Open Pit Copper Mine

Chengmenshan Copper SulphurMine, one of the of the large-scale open pit mine in China, the engineering geology and hydrogeology in the Southern slope of the mine is very complicated and the contact plane between two kinds of sandstone’s form soft-weak layer. Field investigations and reports by operators demonstrated that some instability problems might occur in the southern slope which is situated in zone I and zone II. Southern slope was divided into six sections (I-0, I-1, I-2, II-0, II-1 and II-2) to make the analysis. Slope stability analyses using limit equilibrium and numerical showed that the safety factors of some section are very low (section I-0, I-1, I-2) as a result of this, failure is likely to happen. Therefore reinforcement is very important to increase the safety factor of the three sections, two methods were used; Grouting to increase the slope cohesion (c) and Pre-stressed Anchor then the factor of safety increased more than 1.15.