Geotechnical characteristics of soils from Tourela artisanal gold mining site in Mali and restoration proposals

The village of Tourela is facing progressive degradation of its soils due to unregulated mining activities. The main objective of this research is to study the evolution of the geotechnical characteristics of soils as a function of excavation depth, through field investigations followed by drilling and laboratory tests, in order to understand their mechanical and physical behavior in a post-exploitation context. Grain size analysis, bulk density, and moisture content tests were carried out to determine the physical parameters. The Atterberg limits test was conducted to determine the soil consistency parameters. The mechanical parameters, such as cohesion and the angle of internal friction, were determined through direct shear testing. In the perspective of backfilling mining excavations, the Proctor test was performed to evaluate the maximum compaction energy of the fill material, both on the soil without additives and with the incorporation of 25% and 50% of crushed gravel in the backfill mass. Based on the results obtained, technical solutions are proposed for the progressive restoration of the site, particularly through backfilling and stabilization methods, with a focus on durability, safety, and environmental rehabilitation. This study therefore aims to contribute to the sustainable management of former mining sites and to provide recommendations for future rehabilitation projects.