Cause analysis of water inrush in working face and application of comprehensive control measures

In order to effectively analyze the source and genetic mechanism of water inburst at 3506 working face under complex geological and hydrogeological conditions, water quality analysis and analysis and water inburst coefficient verification were used to determine that the source of water inburst at the mining face was the mixed source of sandstone fissure water in the roof and confined water in the bottom ash. Through the calculation of the coal pillar in the fault area, the comprehensive water control measures such as drainage depressurization and bottom grouting reinforcement are taken. After treatment, the transient electromagnetic geophysical exploration verifies that there is no abnormal area of water rich with low resistance in the treatment area. In each of the three sections of mining, five effective verification holes were constructed, and the maximum water inflow was reduced to 2.2 m³/h, and the maximum orifice pressure was reduced to 0.6 MPa. After calculation and verification, the maximum water inrush coefficient of the reinforced floor was only 0.023 MPa/m, which was far less than the index of 0.06 MPa/m for water inrush coefficient of the coal face damaged by structure damage. During the mining period, the water inflow of the mining face decreased to 22.7 m³/h, a decrease of 68.6%, and the obvious water control effect was achieved.