Simulation Study On Solute Transport In Karst Fissure Water Of Jinning Phosphate Mine In Yunnan Province

Groundwater is an indispensable material basis for sustainable socio-economic development.However,the safety situation of groundwater in China is not optimistic and pollution is serious.To this end,it is necessary for people to understand the general situation of groundwater pollution in China,to be familiar with its pollution pathways and causes of pollution,to proceed from long-term interests,to adhere to sustainable development,and to make China's water structure more scientific and safe.In this paper,combined with the actual project groundwater environmental impact assessment of the 2.5 million t/a mining project of Jinning Phosphate Mine,the numerical value of the carbonate groundwater environment caused by the pit in the Jinning Phosphate Mine Research Area and the infiltration of the dredging fluid from the dumping site Simulation study.On the basis of extensive collection of previous research data,the paper systematically expounds the geological background,aquifer group type and hydrogeological conditions of the Jinning phosphate mine in the field through field investigation and hydrogeological experiments.Through the statistical analysis of the fracture measurement,the three-dimensional permeability tensor is obtained;the water sample is tested in the study area to obtain the water quality status of the area;the hydrogeological drilling,pumping test and dispersion test are carried out in the study area to obtain the relevant hydrogeological parameters in the area.Based on GMS software,this paper simulates the solute transport of pollutants in underground aquifer of Jinning Phosphate Mine.After leachate of mining pit and dump leachate leachate leached to aquifer under abnormal conditions,pollutants migrate to the South and North downstream areas,and pollutants will diffuse continuously,and gradually penetrate into karst fissure aquifer from shallow aquifer.The simulation shows that with the pollutants infiltrating into the second layer of karst fissure aquifer,the groundwater environment will be affected by the better permeability and faster pollutant migration.In 20750 days,0.001 mg/L pollution plume will extend to the Niuxiang water source XJ2,so the water source will be affected to a certain extent.The simulation shows that the transport rate of pollutants in the upper weak permeable aquifer is significantly different from that in the karst fissure aquifer,which indicates that the transport rate of solute is affected by the permeability coefficient.The larger the permeability coefficient,the faster the transport rate of solute is.The migration pattern of pollutants is very similar to that of groundwater flow field,which indicates that groundwater flow provides necessary conditions for pollutant migration.The faster the flow is,the faster the pollutant migration is.The migration direction of pollutant plume is basically the same as that of the main axis of the osmotic tensor ellipsoid,which indicates that the direction of hydrodynamic dispersion is controlled by the osmotic tensor to a certain extent.This paper quantitatively describes the spatial distribution of pollutants in groundwater of carbonate rocks in the study area with time and makes regular analysis,which provides scientific basis for groundwater pollution prevention and control,and has important practical significance.