Management and Utilization of High-Pressure Floor-Confined Water in Deep Coal Mines

This study analyzed the failure characteristics of the coal seam floor induced by longwall mining to manage and eliminate possible hazards associated with high pressure (8.0 MPa) floor-confined water in the Xinjulong coal mine. The disturbed floor was divided into mining failure (MF), water-resistant (WR), and confined water intrusion (CWI) zones. The MF and CWI zones have lost their ability to resist the confined water, so the WR zone is the key for preventing water inrush from the floor aquifer. A thin-plate model for the WR zone indicated that the water pressure had to be decreased to 2.4 MPa or less. Multi-well pumping was used to decrease the floor aquifer water pressure from 8.0 to 2.1 MPa. Moreover, grouting was used to block water-conducting fractures in the floor strata. In addition, classification, purification, and recycling techniques enabled 84.8% utilization of the produced mine water.