Groundwater Environmental Risk Assessment of Underground Coal Mine in the Mine Life Cycle, A Case Study of Hongshan Coal Mine, Zibo City, Shandong Province, North China

It has a great influence on groundwater system, during the process of the coal mine life cycle. The destruction of groundwater system is not only the destruction of structure, but also the social problems caused by the decline or loss of water supply function, as well as the environmental problems affecting ecosystem and human health. The groundwater environmental risk in the coal mine life cycle is complex and long-term. Therefore, a quantitative method for groundwater environmental risk analysis and evaluation is presented. And this method is applied to the Hongshan coal mine. The groundwater environmental destruction of coal mining includes three categories: aquifer structure destruction, groundwater flow field evolution and groundwater contaminants. The groundwater environmental hazard and its social, economic and ecological vulnerability are the core content and keys of groundwater environmental risk assessment in underground coal mine. Besides, 12 main controlling factors were determined and quantified separately in the groundwater environmental hazard assessment. The thematic map of every controlling factor was obtained with the data processing functions of GIS after the data were normalized. Moreover, the influence weight of each factor was calculated using the AHP index method. The thematic map was superimposed with GIS to obtain the groundwater environmental hazard zoning map. The results showed that the hazard area with high, moderate and low are 12.51 km² , 39.02 km² and 10.73 km² respectively. And the social, economic and ecological vulnerability is manifested as the index of destructiveness, vulnerability and resilience. Seven main control factors were determined, and the final conclusion is that the comprehensive vulnerability index of groundwater environment in Hongshan coal mine is as high as 8.55. This research has significance to the management of coal mine groundwater resources.