The Study On Numerical Simulation Of Groundwater Environmental Impact Assessment In Meilinmiao Coal Mine Area

The impact of groundwater environment caused by coal mining should not beoverlooked, thus the focus of environment impact assessment in coal mine areashould be on the content of groundwater evaluation. It is an effective way to forecastthe field evolution trend by numerical simulation, in order to ensure the accuracy ofthe coal mine groundwater EIA.Coal mine groundwater environment impact assessment should focus on regionaland cumulative impact. It should be follow the order of from the regional to the coalmine area in Present Situation Evaluation, and from the coal mine area tothe regional in the Forecast of Impact.Meilinmiao Ida Wushenqi Hujierte exploration area is located in the territory ofOrdos City, Inner Mongolia Autonomous Region. According to the geological andhydrogeological conditions of simulation area, defining the hydrogeology conceptualmodel and mathematical model, and sloving by the FEFLOW software based on FEMmethod. The wet season is selected for the initial flow field, and the dry season forfinal flow field. The fitting results are favorable after parameter adjustment. Thenforecast the change of flow field, taking into account the different mining mode.Studies have shown that the exploitation of Hatoucaidang water source area isthe main reason causing the dropping of phreatic. The largest dropping of phreaticlevel is2.11m caused by coal mine only,23.50m by water source area only, and24.41m by exploitation together. The phreatic flow field, dropping of phreatic leveland burial depth of water table are similar in condition of water source area only andexploitation together. But the change of phreatic flow field and drawdown are small incondition of coal mine only.The volume storage amount of phreatic is195×108m3during current conditions.And the annual average loss of groundwater resource after20years is0.22×108m3/a(including0.12×108m3/a of annual average rainfall infiltration losses,0.26×108m3/a of annual average evaporation losses, and0.36×108m3/a of exploitation). It is identified that the damage to regional groundwater resources, residential andagricultural water, at the same time, the phenomenon of evaporation increased causedby convergence will not appear.