An analysis of sequential water releasing tests of the confined aquifers in a coal mine based on hydraulic tomography

Hydrogeological parameters are important indices to evaluate water-yielding conditions of an aquifer, and an accurate delineation of their spatial distribution is of significance for the prediction and prevention of water-inrush incidents in underground mines. Hydrogeological parameters obtained by traditional water-releasing tests analyses are equivalent values, and the spatial heterogeneity cannot be accurately characterized. Based on cross-correlation analyses between time-dependent head data and hydrogeological parameters, hydraulic tomography is applied to interpret underground sequential water-releasing tests of confined aquifers in the Ningtiaota coal mine in Yulin of Shaanxi, and the spatial distribution of hydrogeological parameters in the study area is also analyzed. The results show that there is a great difference between the northern and southern parts of the working face, and the water-inrush area is located on a highly permeable zone. The transmissivity and storativity gradually decrease from the water-inrush area to the north. The magnitudes of both the transmissivity and storativity are high in the southern part, which indicates a water-yielding abnormal area. In conclusion, we note that the hydraulic tomography is an efficient technique for identifying the heterogeneous aquifer parameters. Underground water-releasing can be regarded as a stimulus source for aquifers. The head data and cross-correlation analyses between the head data and hydrogeological parameters are used to obtain the main geological structural characteristics of the study area. In the analyses of hydrogeological conditions of underground mines, identification of water-yielding abnormal areas by hydraulic tomography in advance can effectively reduce the risk of water-inrush incidents.