A Comparative Analysis of Slope Stability Methods for an Open-Pit Mine in Mongolia

Slope stability is a critical factor in the mining industry, directly impacting operational safety and economic performance. In large open-pit mines, slope failures can cause work stoppages and significant financial losses. Regions like Mongolia, with their complex topography, irregular geometries, and heterogeneous rock conditions, present a particular challenge for assessing slope stability. Conventional two-dimensional (2D) slope stability analysis and deterministic approaches have limitations in accounting for these complex topographies, irregular pit geometries, and lateral resistance forces. For a large open-pit mine in Mongolia, this study applied three-dimensional (3D) analyses with varying slope widths, using both limit equilibrium and finite element methods, to achieve a more reliable stability assessment under complex topographic conditions. To further enhance the reliability of evaluations under heterogeneous rock mass conditions, probabilistic approaches were employed alongside traditional deterministic methods. This enabled a more accurate estimation of safety factors and the identification of potential failure zones. The comparative study results demonstrate that 3D and probabilistic analyses consistently show 17–20% higher factors of safety and lower probabilities of failure than conventional 2D deterministic analyses. These findings highlight the effectiveness of these advanced methods for reliable slope stability assessment in complex geological conditions. Ultimately, the results underscore the importance of incorporating 3D and probabilistic analyses for more accurate and reliable assessments in complex open-pit mining, thereby contributing to improved safety and optimized operational efficiency.