The Study Of Groundwater Environment Change Affected By Manglai Strip Mining

In our country,coal is still the most important part of energy sources at present.The impacts of coal mining on groundwater environment have long been concerned.In this research,the study area is located in a desert steppe,Inner Mongolia—a typical dry region with the long year average precipitation of 163.18mm and an evaporation of 2564.3mm.And drink water in this area is extremely depended on groundwater resource.Therefore,the research about impacts of Manglai strip mining to local groundwater environment is rather importantAfter collecting lots of fundamental achievements on geology and hydrogeology,we conducted 11 hydrogeological boreholes in need,with 7 in the Tertiary phreatic aquifer and 4 in the confined aquifer of Lower Cretaceous.Then,pumping test was conducted in each borehole in order to calculate the hydraulic conductivity on each position.Besides,5 infiltration tests were carried out on unsaturated zone inside of the research area,with a purpose of acquiring hydraulic conductivity.Meanwhile,the exact groundwater head in 3 periods(Nov.2013,Mar.2014 and Aug.2014)had been detected,as well as the quality of groundwater was evaluated.According to these real data,the groundwater contour-maps in both phreatic aquifer and confined aquifer of 3 periods were interpolated.What's more,the background values of groundwater quality were acknowledgedAfter systematic analysis of hydrogeological features and comprehensive understanding of hydrogeological conditions,some conceptualization works were done reasonably to the groundwater system.Thus,the numerical model for groundwater flow was obtained through GMS6.5.By using real-detected data,the numerical model was identified and calibrated.In addition,the flow model was used to predict the possible change of groundwater flow field around each pit(there are 5 mine pits)separately and independently.The prediction results demonstrated that the groundwater head around mine pit decreased clearly and the groundwater head in the confined aquifer showed a much larger drawdown,and its drawdown funnel was rather notable.Furthermore,the flow model also forecasted maximum mine discharge of different strip pitsOn the other hand,the mass transport model based on the advection-dispersion equation was constructed.It was used to simulate and predict the transport distance and range in the Tertiary phreatic aquifer of particular pollutant after leakage-accident In this case,three major contaminations(COD?ammonia nitrogen?petroleum)were simulated to check contaminant range in a transport period of 30 years.The simulation results indicated that the contaminant range of each kind became larger as time goes by,but the excessive contaminant range went opposite.In the end of 30 years,the excessive contaminant range of COD and petroleum disappeared.