Research On The Impact Of Coal Mining On Groundwater Environment

The large-scale development of coal resources,especially the exploitation of coal mines,has brought great pressure on the natural ecological environment in the main coal producing areas and the groundwater environment.Due to the concealment of groundwater,if the groundwater is polluted or the original balance of groundwater is broken,which is difficult to repair during a long time and threaten the human survival and activities.In the coal mining process,the aquifer is damaged because the ground surface is excavated,which forms an underground funnel affecting the recharge,runoff and excretion of groundwater in the mining area of the mine.This causes the problem of the change in groundwater volume.Once the groundwater volume changes,the probability of infiltration of mine water and domestic sewage with pollution factors into contaminated groundwater under abnormal conditions will also increase.The main points of this article are as follows:1.The matrix method is selected by comparative analysis,meanwhile,the groundwater level,groundwater recharge,and discharge are identified as the influencing factors for assessing the groundwater volume,which is based on various conditions.In addition,the height of the overlying aquifer fracture zone is used as the evaluation of aquifer's predictive factors.Ammonia and nitrogenroutine are act as a predictor of domestic sewage,and special pollution factor fluoride represents a mine water pollution factor.2.Combining the height prediction of the so-called water-conveyed fracture zone and the Visual Modflow numerical simulation software,the groundwater flow field prediction simulations show that the height of the water-guiding crack zone in each coal seam is around 6.58 m to 71.15 m,and the effective water-retaining thickness of oil shale is 89.69 m.Coal mining has less effect on the overlying aquifer of oil shale,but it provides a dredging impact on the aquifer and drained in the form of mine water.The completion of full-well drilling cause the 968.44 m~3/d loss of underground water to the surrounding water body.Due to the effect of subsidence and stagnant water,the groundwater supply to the surrounding water is reduced by 0.011 m~3/s,which proves that the change of local topography has lost part of the replenishment of groundwater to surrounding water bodies.In terms of water quality,ammonia nitrogen and fluoride are calculated by analytical method.Under abnormal conditions,ammonia nitrogen concentration was 0.007673 mg/L at 10 m from the point of penetration.On the 10th day of fluoride,the concentration was 0.002966 mg/L at a distance of 10 m from the point of penetration.The results show that the wastewater generated by coal mining will have an impact on groundwater quality under abnormal conditions.