Discussion on karst groundwater migration law under mining conditions in the Yutianbao coalmine of Chongqing

Chongqing is located in southwestern China. It hosts five major stateowned coalmines in karst hilly areas, where geological conditions are complex. For further research on groundwater migration law under mining conditions in these areas, we put the tracer on the limestone surface of the Changxing segment in the coal seam roof to conduct connection tests of receiving points which are deployed on different levels of underground roadways and different mining areas. Results show that chloride content at receiving points after rainfall have three changing trends, which are increase, decrease and unchanging. The Changxing segment limestone groundwater migrates to the mining section below erosion datum and basically has no discharge in the relatively stable overlying strata of the mining area. The study on tracer change characteristics in different mining areas provides information for understanding of groundwater migration laws and water prevention and control in mining area.