Cooperative monitoring and numerical investigation on the stability of the south slope of the Fushun west open-pit mine

The south slope of the Fushun west open-pit mine in China is geologically complex and is a high-steep rock slope. In recent years, a larger deformation has appeared in the south slope, with the gradual formation of a potential landsliding block that is estimated to be over 300 m³. The east and south boundaries of the block have been identified using different monitoring techniques. However the west boundary has not yet been clearly delineated, a situation which undermines safety assessments and the slope management of the mine. The focus of this was on how the microseismic technology, DInSAR technique and the numerical method are used to determine the shape and formation of the west boundary of the potential sliding block. We found that the upper part of west boundary as determined by numerical simulation is concordant with that determined by microseismic monitoring. The surface deformation area coincides with the DInSAR monitoring results and damage area based on in situ observations. Numerical simulation provides supplementary information on the distribution of stress and the formation process of the west boundary that cannot be observed directly on-site. The microseismic monitoring system was able to capture the progressive rupture of the west boundary during the deformation of the block. The cooperative monitoring strategy together with the numerical simulation can delineate the sliding surface and provide a method for a comprehensive assessment of the slope stability of other similar open-pit mines.