Room and pillar sizes are key factors for safe mining and ore recovery in open-stope mining.To investigate the influence of room and pillar configurations on stope stability in highly fractured and weakened areas,an orthogonal design with two factors,three levels and nine runs was proposed,followed by three-dimensional numerical simulation using ANSYS and FLAC3 D.Results show that surface settlement after excavation is concentrically ringed,and increases with the decrease of pillar width and distances to stope gobs.In the meantime,the ore-control fault at the ore-rock boundary and the fractured argillaceous dolomite with intercalated slate at the hanging wall deteriorate the roof settlement.Additionally,stope stability is challenged due to pillar rheological yield and stress concentration,and both are induced by redistribution of stress and plastic zones after mining.Following an objective function and a constraint function,room and pillar configuration with widths of 14 m and 16 m,respectively,is presented as the optimization for improving the ore recovery rate while maintaining a safe working environment.
This paper dealt with the development of a two-dimensional(2D)mathematical model for column leaching and confirmed the important simulation parameters through experiment.The unsaturated state of the variably saturated flow column and the solute transport of copper ions were studied during leaching.The fluid flow problem was handled using the Richards equation on the premise of an ambient pressure column air,where the van Genuchten formulas were applied to define the nonlinear relationships of pressure head with the retention and permeability properties.The ore column permeability test gave a varied hydraulic conductivity,which was analyzed in the model.In the solute transport problem,the copper ion concentration was solved using the advection-diffusion-reaction equation whose reaction term was determined by the joint analysis of experimental copper leaching rate and the shrinking core model.Particle-and column-scale leaching tests were carried out to illustrate the difference and connection of copper extraction in both processes.This fluid flow and solute transport coupled model was determined through the finite element method using the numerical simulation software,COMSOL Multiphysics.
Xiu-xiu MiaoAi-xiang WuBao-hua YangJin-zhi LiuSheng-hua YinHong-jiang Wang
