Discussion on Water Inrush Coefficient Method Applied to Predict Water Inrush Danger of Seam Floor Based on Gaojiata Mine as Example

In order to predict the water inrush danger from Ordovician limestone during the coal mining under the pressurized aquifer in deep mine and to rationally divide the dangerous zones, a study was conducted on the North China type coalfield features, simulation test and related information and the comprehensive analysis and comparison was conducted on the previous water inrush coefficient formulas.Based on the circumstances, a revised formula of the water inrush was provided and t he water inrush danger and risk zone of the Ordovician limestone during the pressurized mining in No.9 seam of Gaojiata Mine was predicted and divided.The results s howed that the water inrush coefficient could be revised from 0.0430.091 MPa/m to 0.0670.127 MPa/m and the water inrush subarea could be revised from the relative s afety area-the relative danger area to the relative danger area-danger area. The water inrush accident occurred from pressurized mining in the actual production mine V erified the rationality of the water inrush coefficient revised formula.