Stability Analysis and Optimal Design of Ultimate Slope of an Open Pit Mine: A Case Study

To avoid over-tailing and limit the risk of failure in open-pit mines, choosing an ideal and stable slope is critical. The major goal of this study was to provide a stable and optimal design for the ultimate slope of the Shadan Open Pit Mine using numerical modeling to calculate the minimum factor of safety equal to 1.20 under various situations of the slope's geometric specifications. In FLAC3D program, the finite difference method (FDM) was used according to the shear strength reduction (SSR) approach to determine the factor of safety (FOS) by reducing the shear strength. As a result, by adjusting the geometric parameters of the ultimate pit slope, a set of three-dimensional (3D) numerical models were examined and evaluated in various scenarios. Moreover, Shear strain and horizontal displacement in the model are the most affected by changes in the factor of safety, with the maximum shear strain and horizontal displacement being associated with Scenario 5 with the minimum factor of safety. Furthermore, the model of Scenario 1 with the maximum slope height had the highest vertical displacement, indicating the least effect of the factor of safety.