Research on the safe mining depth of anti-dip bedding slope in Changshanhao Mine

Abstract

Safe mining depth constitutes the key to the open-pit mine development, it is significant to research the safe mining depth. First, According to the field geological investigation and geophysical exploration, the existing landslides were summarized and analyzed to obtain the potential destabilization and failure modes in mine, which laid the effective reference for the slope stability analysis in the Changshanhao mine. Then, The entire three-dimensional calculation model of north-east pit was established through FLAC3D software. According to the calculation results of displacement nephograms, plastic zone and shear strain, it was concluded that the entire instability might occur during excavation of the north-east pit in accordance with the designed final boundary. Following, ten sections of north-east pit were selected to calculate the slope stability through 3DEC software, and four types of mining depth elevation designed for each section were considered. According to the numerical calculations of each slope stability under different mining depths, for ensuring the mining safety of north-east pit, the boundary that is 84 m higher than the final boundary is recommended, thus the safe mining depth elevation and ultimate stable slope angle were determined as 1216 m and 38 degrees, respectively. Under the proposed safe mining depth condition, the slope of north-east pit can keep its stability, laying a basis for the safe mining depth determination of similar open-pit slopes.