Comprehensive Engineering Geological Analysis on Large-Scale Anti-dip Slopes: A Case Study of Changshanhao Opencast Gold Mine in China

Flexural toppling failure of large-scale anti-dip slopes constitutes a significantly rare phenomenon. With regard to the large-scale anti-dip slope instability at the southwest stope of Changshanhao Opencast Gold mine, in this work, a field engineering geological survey on the Changshanhao open stope was conducted, to investigate the structural plane features of the corresponding slope rock mass. Moreover, an equatorial horizon projection and strike rose diagram were utilized to determine the preferred structural plane of the joint fissures; the exposed rock mass integrity zoning of slope and the rock sample property testing on the main lithological compositions in the stope were also established. Based on the results of previous field investigations and indoor rock mechanics experiments, along with the occurrence conditions of stratigraphic structures unmasked by existing engineering geology borehole data, geographical explorations and mining engineering, the failure mode of southwest stope slopes were also determined. Finally, several suggestions were provided on the reinforcement and treatment of dangerous slopes within the ultimate mining boundary, consequently laying a foundation for sustainable safe mining.