Demonstration of a technical system for water disaster prevention and control when mining under sandstone aquifers

A heterogeneous sandstone aquifer (K8) lying above a no. 3 coal seam greatly threatens the safety of mining operations at working faces in the Zhao Coal Mine. This study demonstrated a disaster prevention approach involving the transient electromagnetic method and drainage drillings into the water-rich areas before mining, and evaluated the drainage effect. The research followed three steps: 1) three water-rich areas were identified in the sandstone aquifer K8; 2) in the water-rich areas, three drilling sites were designed, and ten holes were drilled; 3) water outflow from the drilling holes decreased obviously over time, and the water-rich areas almost disappeared following water drainage. The total volume of drained water was more than the predicted value; hence, the approach met the requirements for water drainage. This technical system of water disaster prevention and control was proposed for circumstances of mining under roof aquifers, which included geophysical prospecting, drilling exploration, water drainage, and effect evaluation.