Mechanical properties and slope stability of a copper mine waste dump in China

The development of mines creates substantial amounts of soil-rock mixture (S-RM) waste that is accumulated as waste dumps. These dumps pose significant safety hazards that require management. In this study, S-RM was sampled from a waste dump at a copper mine in Jiangxi Province, China. Consolidated-undrained triaxial tests were conducted on four gradations of S-RM specimens. Numerical simulations of dump slope stability were performed by considering factors such as groundwater level, rainfall intensity, and root reinforcement depth. The findings are as follows: (1) cohesion and friction angle are sensitive to rock content; (2) the power-law model outperforms the Duncan-Chang model in fitting triaxial data; (3) the stability of the dump deteriorates as the groundwater level gets shallower; (4) the factors of safety decrease with increasing rainfall duration and intensity with an approximately exponential decay pattern; (5) vegetation root reinforcement improves slope stability; however, extreme rainfall can trigger perched water accumulation, which can compromise stability. These findings provide valuable indicators that can assist in managing the safety hazard posed by such waste dumps.