Study On Effect Of Mining In Groundwater With Numerical Simulation

Coal mining has a dynamic and continuous effect on groundwater. The balance state of discharge are often broken by mining which cause mine drainage, aquifer dry up, mining damage and so on, this change make the groundwater system more complex. The effect of mining on groundwater not only at the amount of water, but also at water quality, especially the shutting down of mine which may cause layer-through pollution can bring serious damage to groundwater of mine area.This paper based on mine area of Zichuan, with the combination of theory analysis, algorithm evaluation, numerical simulation, analyze the possible effect on groundwater which caused by Longquan coal mine. Firstly, evaluate the pollution state of groundwater in this area with Fuzzy math and with the combination of specific situation of mine water quality, result shows that Hongshan,Longquan and the area around them have the most serious pollution situation, which provides a basis for the content following. Secondly, base on the analysis of boundary condition and hydro-geological conditions, built numerical simulation model of groundwater flow with GMS. Then simulate the groundwater in this area after verify the accuracy requirements, which include two aspects:groundwater flow simulations before and after the shutting down of mine. Finally, built the model of groundwater quality through the convert between MODFLOW and MT3D, analyze the groundwater quality after the shutting down of mine.The results of simulation show:mining effect on groundwater still exist after the shutting down of mine, the groundwater funnel also will exist for a long time even though the drain is stop; the aquifers at this coal series and Ordovician below have direct hydraulic connection, and the pollutants will spread to aquifers at Ordovician cause contamination of large area, because of the rise up of water level after draining stop.