Effects Of Hydrogeological Parameters On Water Inflow And Solute Transport Of Pollutants In Mining Area

After summarizing the existed research methods of mine water inflow and groundwater solute transport,taking a spodumene in Ganzi Tibetan Autonomous Prefecture of Sichuan province as the research object,through the establishment of forecasting model of water inflow,steady flow and solute transport,the mine water inflow and pollutant transport in different hydrogeological parameters are forecasted.The predicted results are as follows:(1)Through the single variable method,the relationship among permeability coefficient,aquifer thickness and mine water inflow was determined:The water inflow increases linearly with the increase of permeability coefficient,and the influence of permeability coefficient on the hole production stage is greater than that of the open pit stage.The amount of water inflow increases first and then decreases with the increase of aquifer thickness in the Open-pit stage.The water inflow volume increases with the increase of aquifer thickness in the hole mining stage.(2)MATLAB is used to simulate the influence of three factors,namely permeability coefficient,aquifer thickness and dispersion coefficient on solute transport:The impervious capacity of tailings pond has a direct impact on the diffusion concentration of pollutants in underground water.When the permeability coefficient of the impervious layer is greater than 0.66 m/d,the maximum diffusion concentration of the pollutants in the local groundwater reaches a stable saturation state,and the maximum diffusion concentration is approximately equal to the initial concentration of the pollutants.The maximum diffusion concentration of pollutants in local groundwater increases with permeability coefficient,when the permeability coefficient varies from 0.16 m/d to 0.66 m/d.The maximum diffusion concentration of pollutants is inverse correlation with the thickness of aquifer and dispersion coefficient,and the dispersion coefficient is not obvious at 0.2~0.4m~2/d and0.6~0.8 m~2/d,but the dispersion coefficient has a significant influence on the maximum diffusion concentration of the pollutants when the dispersion coefficient is in 0.4~0.6 m~2/d and 0.8~1 m~2/d.The regression equation between the three factors and the diffusion concentration is determined through the simulation results,and the influence of these three factors on the diffusion concentration is obtained as follows:aquifer thickness>diffusion coefficient>permeability coefficient.(3)If the waste rock site runs in non-normal condition(without impermeable liner),the pollutants will move downstream with the direction of the flow.As time goes on,in the tailings reservoir and the downstream direction of the reservoir area,the three pollutants of Be,Cd and Ni will cause the maximum contaminated areas of the 0.7182 km~2,0.675 km~2and 0.6066km~2,respectively that the pollutant concentration is more than the limit of class III water quality standard of GB14848-93.