The Study Of Groundwater Environmental Impact Prediction In Subside Seeper Area

As China's major energy,coal provides the material basis for China's economic and social development.However,coal mining will result in the loss of groundwater resources,groundwater quality deterioration,and intensify supply and demand of water resources.China's coal mine are mainly exploited by underground mining methods,which will destroy the overlying and underlying aquifers spatial structure,and lead to the loss of groundwater resources.Water drainage in the process of underground mining will cause the aquifer dewatering and change groundwater environmental,so we need to strengthen the protection of groundwater resources in the coal mining process.Therefore,the study of the impacting mechanism of underground mining on groundwater environment and predicting the impact of coal mining on groundwater can provide the basis for water-preserved mining.The paper take a mine field for an example to study the impact of coal mining on groundwater resources in upper aquifer.According to the stratigraphic structure and hydrogeological conditions,mine discharge is composed of groundwater in the coal strata.The main impact of coal mining on groundwater is water evaporation in subside seeper area.Two simulation methods are adopted to simulate and forecast the impacts of coal mining on groundwater flow field,water level and groundwater quantity in the upper aquifer.The first method considers the leakage from the upper aquifer caused by water drainage in the process of underground mining.Simulation results show that groundwater flow field changes little in the process of coal mining.The mine exploitation will result that groundwater level decrease by 0.24m in phreatic aquifer and 0.14m in confined aquifer and groundwater quantity lose by 260 million m3.Method two coupled with surface subsidence seeper predict the impact of coal mining on groundwater.Simulation results show that groundwater will flow to the subsidence area.The mine exploitation will result that groundwater level decrease by 5.32m in phreatic aquifer and 2.09m in confined aquifer and groundwater quantity lose by 143 million m3.Comparative analysis of the two methods,the results show that ground subsidence seeper caused by coal mining considerable influence groundwater environment.The ground subsidence seeper will cause upstream groundwater level decrease by 5.15m in phreatic aquifer and 1.98m in confined aquifer;western and eastern groundwater level decrease by 3.60m?4.46m in phreatic aquifer and 1.45m?1.81m in confined aquifer;downstream groundwater level decline by 0.06m?40.38m in phreatic aquifer and 0.11m?0.67m in confined aquifer;groundwater quantity lose by 117 million m3.The results show that the second method can be more reasonable to predict the impact of underground mining on groundwater environment under the condition of the subsidence seeper.