Engineering geology and mechanism of multiple landslides in a large open-pit mine: the case of the Copper Mine in Qinghai Province, China

Landslides are a commonly occurring hazard in open-pit mines. Despite extensive research on this phenomenon, there is still a lack of understanding of the mechanism involved in landslides in open-pit mines in certain geologic settings. To reveal the mechanisms of multiple landslides in large open-pit mines, the geological engineering conditions in a Copper Mine were analyzed in detail. The results were supplemented with on-site investigations, allowing the characteristics of the large-scale open-pit landslide events to be summarized. The mechanisms by which geological engineering conditions induced multiple large-scale landslides, slope groundwater, freeze–thaw cycles, and blasting vibration were determined. The results show that four dominant structural planes are located throughout the serpentinite. The slope rock mass is divided into five engineering geological rock groups. The slope failure forms include plane landslides, collapses, and combined failure forms. The area of the collapsed body becomes gradually closer to the top of the mountain, indicating that the three collapses have certain inheritance and development. Local dangerous rocks at the top of the mountain will eventually slide and are unstable. The deformation of the surrounding rock is accelerated, and collapses and landslides are likely to occur in the later stage of deformation. The research results provide a reference for the mechanism analysis of similar mine landslide disasters.