Geomechanical Study of Inata Gold Mine Pits Rock Slopes, Burkina Faso (West Africa)

Pierre SAWADOGO, Ousmane BAMBA, Saga SAWADOGO, Tikou BELEM

Abstract: The Inata gold Mine, active since 2009, is an open pit mine operated by Avocet Mining. The mine is located 280 km northeast of Ouagadougou, the capital, in the western section of the Arbinda-Djibo volcano-sedimentary paleo-proterozoic belt. One of the main difficulties facing the mine is the high frequency of the footwall rock failures, affecting directly workers? safety and the economic viability of the project. This paper presents the stability analysis of rock slopes of the northern pit of the Inata gold Mine. The results indicate that the high degree in footwall failures is the main cause of the mine instability. The Rock Quality Designation values ranged from 6 to 10, and the Rock Mass Rating values from 35 to 45, suggesting that rock masses were initially composed of highly fractured and low grade materials. Furthermore, the Mining Rock Mass Rating values (18-30), clearly showed that mining greatly contributes to the footwall instability in the Inata gold Mine. The kinematic modeling of footwall failures also suggested a possible occurrence of planar and corner failure of the pit walls.

Keywords: Pit, stability, slope failure, kinematic analysis