Back analysis of inter-ramp slope failure in Teghout copper mine

Slope stability is one of the most important issues in open pit mining design. The main purpose of any open pit mine design is to propose an optimal excavation configuration, considering safety, ore recovery and financial return. An accurate pit slope design which accounts for the mine geology, structural geology, rock mass properties, and hydrogeology models of the mine area, drastically enhances the whole mining operation. The present paper investigates the failure of an inter-ramp slope in the Teghout mine using the limit equilibrium and finite difference approaches. The geotechnical properties of the rock mass were obtained using field investigations and back analysis. In-situ shear strength parameters of the rock mass were back calculated using the limit equilibrium method. Utilizing sensitivity and probabilistic analyses, the internal friction angle and cohesion of the rock mass were obtained 33.5 degrees and 13.5 kPa, respectively. On the other hand, slope failure mechanism and the effect of the slope height and slope angle on the stability of pit slope were investigated using the finite difference method, and suitable slope angle was proposed.