Analysis of the Unstable Coal Mine Subsidence Areas Water Characteristics and Factors: Take Xieqiao and Zhangji Coal Mines Subsidence Areas for Example

The paper mainly analyzed the physicochemical indexes and got the situation of subsidence water by inspecting during unstable form stage. The physicochemical indexes were inspected including temperature, transparency, BOD₅, COD_Cr, total alkalinity, total hardness, ions, etc. The result showed that all the subsided areas water were subjected to pollution, and the main pollution indexes were BOD₅ and COD_Cr; dissolved oxygen was richer; the total alkalinity, total hardness, chloride, calcium and sulfate ion were growing with ages. For the difference of environmental influence factors, the quality of water in Xieqiao coal mine are worse than Zhangji coal mine. And through analyzing the environmental influence factors, the study provides a theoretical basis for utilization the resource of subsidence area.