Roof hydraulic properties variation mechanism in arid mining areas.

Coal mining in Jurassic coalfields of the arid Northwest area has damaged the local water resources greatly. Basing on the analysis of diachronic changes of the drainage and water balance of Jinjie Coal Mine, the paper gave some explanations of the changes of circulation patterns of groundwater before and after the mining. According to the changing characteristics of the water levels of pore water, fissure water and mixed water of double aquifers before and after mining, it was believed that the variation of the hydraulic properties of the roof aquifer in the mining area is mainly induced by the unified evolution of the transmission and closing property of roof aquifuge during the promoting process of mining face. The variation of the transmission and closing property of roof aquifuge changes the circulation pathways of mine groundwater, and the heavy-water deposits could be formed in the arid area. Also, the paper holds that the prediction method of real-time mine inflow based on variations of roof hydraulic properties will be one of the key issues in the future studies of deposit hydrogeology. [ABSTRACT FROM AUTHOR]