Study On Groundwater Pollution Risk Assessment Of Abandoned Coal Mine

Due to the depletion of resources, resource integration and eliminate backwardproduction capacity, a number of mines will be closed. After the mine stopping thedrain, mine water would quickly rebound, and underground mine water carryingpollutants contaminated groundwater would cross through mining fissures, faults,closed adverse drilling, that caused underground water cross strata pollution, thusgroundwater pollution because of mine closure has becoming one prominentenvironmental problem in abandoned mines. Since the hydrodynamic field andabandoned mine water highly complex chemical environment, the currentgroundwater pollution risk assessment methods and related technical specificationscannot be applied on abandoned mine groundwater. Groundwater resources protectionand management were very difficult. Therefore, based on a nationwide survey andanalysis of mine water, this paper categorized the water pollution types, proposedabandoned mine groundwater pollution model, built evaluation model on minegroundwater pollution risks which was based on the theoretical risk of groundwaterpollution, developed the abandoned mine groundwater pollution risk assessmentsoftware, and established a risk-based assessment of groundwater pollution fromabandoned mines risk management technology processes. Main research results areshown as follows:(1) The mine water samples of269coal mines in the major coal-producingregions were investigated and tested, and the chemical characteristics of mine waterregional differences were discussed. According to the characteristics of the water,mine water including the following categories, common components mine water, acidmine water, high salinity mine water, high sulphate mine water, fluoride mine waterand special component mine water., and the paper identified the characteristics of themine water pollution factors, including sulfates, iron and manganese, high salinity, pH,fluoride and trace organics.(2) The paper investigated the situation about mine closing in Huainan-Huaibeiregion, west Shandong region with Fengfeng, Shenyang, Jiaozuo, and analyzed theabandoned mine groundwater pollution case in Xuzhou and Zibo. Based on thesources of pollution and pollution pathways,6pollution models were proposed:1)Infiltration pollution by abandoned mine subsidence water;2) Leaching pollution by abandoned mine solid waste;3) String pollution by roof layer water flowing fractured;4) String pollution by bottom layer of polluted mining fissure;5) String pollution bybad drill enclosed layer;6) String pollution by fault or collapse column string.(3) This paper proposed abandoned mine groundwater pollution risk assessment"two sources and one channel"(pollution, water source, pollution channel). Based ontheory of groundwater pollution risk assessment, this paper created abandoned minegroundwater pollution risk evaluation index system and evaluation model. Evaluationindicators contained the three-level indicators including pollution (abandoned mine),pollution channel, pollution receptor (target aquifer), and15secondary indicators.And cluster analysis, expert advice, hierarchical analysis, expert scoring methods forall indicators were graded and weight. Based on the principles and methods of thefinal index Diego, this paper established abandoned mine groundwater pollutionweighted comprehensive risk assessment exponential model.(4) Based on.Net platform, C#language and database technology, abandonedmine groundwater pollution risk assessment index model of visual programming wasdesigned, and the abandoned mine groundwater pollution risk assessment system wasdevelop. By the evaluation system, Xuzhou Hanqiao mine, Zibo Hongshan mine andZouocheng Tangcun mine were evaluated. The results were consistent with the actualsituation, that proved the evaluation model and the software system had betterapplicability.(5) This paper summarized the risk management status and advanced experienceon coal mine closure, analyzed the risk management of closed mines groundwaterproblems. Based on risk assessment theory, the risk management processes for mineclosing was developed, including preliminary investigation, risk assessment and riskmanagement, and risk prevention.The research results deepened the understanding of abandoned mine pollutionmechanism. Abandoned mine groundwater pollution risk evaluation index system wasbased on sufficiently. The abandoned mines groundwater pollution risk assessmentand the risk management technology provided important technical support for theresource-exhausted mining groundwater environmental protection.