Groundwater Numerical Simulation Research On One Mining Area Based On GMS

Coal resources promote the social and economic development of our country,but the exploitation of coal will have some unnegligible effects on the ecological environment,such as ground subsidence,surface cracks,groundwater level decline,water pollution,seawater invasion,and desertification etc.This paper takes Jinhai Coal Mine as an example and uses GMS software to simulate and predict the influence of coal mining on groundwater in the area.In Datong Jinhai Coal Mine,many kinds of water-conducting fissure zones have been produced in the course of perennial mining and production,which has destroyed the original hydrogeological environment,thus affecting the water level and water quantity of the aquifers in this area.In addition,In the process of coal mining,processing and production,pollutants will be produced,including radioactive and nonradioactive contaminants,such as natural radionuclides,suspended substances,fluoride and so on.Based on the actual hydrogeological data of the mining area and the surrounding area,various parameters needed for modeling are obtained,and the groundwater flow model and solute migration model in the studied area are established.In this paper,the influence of roof drainage on the water level and water volume of the aquifer with water supply significance is predicted after the first harvest period(3.8a)and the end of service period(16.8a).At the same time,based on the groundwater flow field,MT3 DMS was used to simulate the migration and diffusion of pollutants in gangue field after leaching.The horizontal movement of pollutants in the aquifer and the pollution degree and range of groundwater quality in different periods of pollutant migration and diffusion were predicted.The effects of pollutants entering groundwater on water quality and water environment of diving aquifer are discussed.The result of water flow simulation prediction shows that the coal mining will not affect the flow field of Ordovician ash water in a short period of time,and the water level of Ordovician ash will decrease in a long period of time,but the flow direction of groundwater will not change.Therefore,the long-term coal mining has little effect on the flow field of the Ordovician aquifer.and the coal mining will directly affect the drainage of the Carboniferous and Permian aquifer,and the water level of the aquifer will decrease.This will then result in an increase in the water level difference between the overlying aquifer and the aquifer in the system,and the overlying aquifer will be recharged from the top to the bottom,thereby causing the water level of the overlying aquifer to decrease,so that in the case of a coal mine for a long period of time,The overlying aquifer of coal seam will be affected.The simulation results show that after the pollutants enter the aquifer,the contaminants migrate downstream in the direction of the water.After 5 and 10 years,the halo of fluoride moves about 130 m and 270 m respectively.After 30 years,the pollutants migrate along the valley,and the migration distance is about 800 m and 750 m respectively.and the migration of the natural radionuclides in the groundwater is slower,after hundreds of years or even the previous year,there is obvious migration behavior,and the concentration of nuclide in some areas of groundwater will gradually accumulate,and its migration velocity and concentration are related to the velocity of groundwater,the nature of the solute factor itself,and the properties of water bearing medium.