The Optimization Of Slope Angle Based On The Mining Of Remnant Ores With Complicated Civil Mined-out Areas

Great attention has been paid on the exploitation of remnant ores with civil mined-outareas along with the increasing requirement on mineral resources. The existence of largenumber of civil mined-out areas brings about serious damages to primary ore structure, andmakes the exploitation more difficult, especially those civil mined-out areas in the open pitslope, which often lead to geological disasters such as landslides and mudslides, affecting theeconomy benefits of the mines and threating the safety of the staffs and equipments. How tomaximize the recycling of the remnants ores underlain the slope with mined-out areas on thepremise of the stability of the slope and the safety of the production is a pressing problem.Based on comprehensive analysis of literature and information both home and abroadand regarding a large open-pit bauxite mine slope and civil mined-out areas as the researchsubject, start from the influence to the slope stability by civil mined-out areas, fieldinvestigation, academic research and simulation analysis are adopted to analyze the stabilityof slope with civil mined-out areas and optimize the slope angle. The main results are asfollows:(1) By on-site investigation and statistical analysis, the dominant joints of slope rockmass and distribution characteristics of mined-out areas are figured out.Take rock qualitydesignation as the index value, the quality of sandstone is evaluated to be fine.(2) Stability theories include deformation and failure type, movement mechanisms ofslope with mined-out areas are studied systematically, making a theoretical foundation for thefollowing study.(3) On the basis of digital terrain model, a3D geological model of slope is built by3DMINE and imported to ANSYS for analysis by self programming. The impact on slopestability by mined-out areas under different working conditions is studied. Results show thatthe trend and scale of mined-out areas have a significant effect on slope stability. The trend isthe most sensitive to the maximum principal stress while the span is the least.(4) A simplified3D design calculation model of slope is constructed on the basis ofon-site investigation. Slope angle is optimized by in-pit dumping, when safety factor is1.5,1.3and1.1respectively. The simulation results show that in-pit dumping can effectivelyimprove the stability of the slope and increase the recovery rate of resource.