Lamine BAR^1,, Déthié SARR¹, Mamadou Koné²

Slope stability in the open-pit mines of the Kédougou–Kéniéba belt, particularly at Sadiola (Mali), is a critical factor for both operational safety and economic performance. To assess slope stability, this study integrates three complementary approaches: back-analysis of past instabilities, structural mapping using mapping windows and scanline surveys, and kinematic analysis of discontinuities. The results indicate that slope failures are primarily controlled by structural discontinuities, with a predominance of planar failure mechanisms. Only 15% of the recorded instabilities affect competent rock, whereas 55% involve limited volumes confined to 10 m high benches, reflecting the predominantly superficial character of the observed failures. Kinematic analyses reveal variable stability conditions across the mine, with higher susceptibility identified on the western and southern pit walls. Based on these findings, geometric optimizations are proposed to improve both slope stability and mining productivity. These include increasing bench height from 10 m to 20 m while reducing the face angle from 90° to 75°. The inter-ramp angle is set at 35° in saprolitic materials (overall height of 50 m) and 55° in competent rock (overall height of 100 m), while a steeper angle of 60° is maintained on the eastern wall due to more favorable structural conditions. Berm design is further optimized through the introduction of a second ramp on the eastern wall. These adaptations provide a balanced compromise between geotechnical safety and operational efficiency within the structurally complex environment of the Sadiola open pit mine.

Slope stability, bench geometry, kinematic analysis, open-pit mining, Sadiola, Kédougou–Kéniéba inlier