Optimization of Bench Geometry for Efficient Slope Stability and Overburden Removal in Open Pit Mining

Open-pit mining operations require a careful balance between maintaining slope stability and minimizing the amount of overburden to be removed. In this study, different bench geometries were examined to determine the most efficient configuration that satisfies both safety and economic considerations. Thirteen pit models were created and analyzed through finite element simulations, and the results were further evaluated using the Response Surface Methodology (RSM) based on a three-factor, three-level Box-Behnken experimental design. The analysis focused on three key parameters: bench height (H), berm width (W), and bench slope angle (β). Optimization was carried out to achieve a factor of safety (FoS) of at least 1.2 while minimizing overburden removal. The optimal design was obtained for H = 8 m, W = 8 m, and β = 75°, yielding a FoS of 1.23 and a stripping ratio of about 20.6 m³/ton. Verification through finite element modeling confirmed the reliability of the proposed model with 98.3% accuracy. The findings emphasize that integrating numerical modeling with experimental optimization techniques can effectively guide safe and economically viable open-pit designs.