Quantitative evaluation and prediction of water inrush vulnerability from aquifers overlying coal seams in Donghuantuo Coal Mine, China

The water inrush vulnerability from overlying aquifers is evaluated for a coal seam in the Donghuantuo Coal Mine, China. The water inrush vulnerability is based on superposition of two zoning maps—water abundance map and connectivity map. The water abundance zoning map was derived from a comprehensive analysis of six types of geoscience data, including (1) lithological changes of the overlying aquifer (2) geological structure, (3) pumping test results, (4) seepage field of water inrush event, (5) geochemistry, and (6) loss of drilling mud. The connectivity map was constructed based on comparing the numerically calculated height of the induced fracture zone above mining areas with the thickness of formation between the coal seam and the overlying aquifer. Visual Modflow was used to predict the mine discharges at working face 2,284 under both natural and mining conditions. Based on the water inrush vulnerability map and the modeling results, advanced dewatering from the overlying aquifer is proposed as the main prevention and control measure against the overlying-aquifer water inrush.