Scanning for water hazard threats with sequential water releasing tests in underground coal mines

Water hazards threat the safety of underground mining. A detailed characterization of hydraulic parameters is helpful for the design of engineering projects to prevent underground water hazards. Utilizing aquifer's natural artesian condition, water releasing tests are often performed in China's underground mines. In this research, we propose to interpret water releasing test data with hydraulic tomography (HT) technique. A 216-hour duration test was performed to localize water hazard areas in Ningtiaota underground coal mine. Groundwater was released with four sequential stages from 30 boreholes. HT analysis clearly shows that the study area has a potential water hazard region in southern part by only using data from the first two stages, which coincides with existing water inrush incident location. With the addition of more pressure responses from stages 3 and 4, it discovers low transmissivity and storativity values in northern part. Our numerical examples further demonstrate that sequential water releasing tests produce comparable hydraulic parameter distributions to tomographic tests. In the end, we conclude that water releasing tests aided by HT technique can leads to a high resolution characterization of water hazard aquifers.