A. Alikhani - Mining Engineering Department, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran.
M. Taheri Moghadder - Mining Engineering Department, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran.
H. Mohammadi - Mining Engineering Department, Faculty of Engineering, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran

One of the most effective parameters in economics of open-pit mines is the pit slope angle, so that the slope angle more than the optimum value increases the probability of a large failure in the pit wall and the slope angle less than the optimum value leads to increasing stripping ratio and reducing net present value of mine. Therefore, in this paper, considering the limit equilibrium methods of modified Bishop and modified Janbu and numerical models of the slope stability analysis, the effect of overall slope angle on the Economics of open pit mines was investigated. In addition, it was shown that selecting the overall slope angle less than the optimum value leads to reducing the depth of open-pit mining (the ultimate pit depth) and consequently, reducing the net present value of mine. Finally, in homogenous and Isotropic media, the results of Bishop and Janbu and numerical modeling are close together.

Slope Stability, Open-Pit, Bishop and Janbu methods, numerical model, optimum overall slope angle