Determination of Water‐Proof Coal (Rock) Pillar Height in Mining Coal Seam Group under Water‐Bearing Rock Stratum

In order to determine the reasonable height of water‐proof coal (rock) pillar when mining multiple coal seams under aquifer, this paper analyzes the expansion height of water‐conducting fracture zone when coal seams mining. Considering the expansion law of water‐conducting fracture zone in coal seams mining, two schemes of coal seams mining in upper and lower groups and one‐time mining of all coal seams are designed for comparative analysis, and the height of water‐proof coal (rock) pillar is determined based on the expansion height of water‐conducting fracture zone. The results show that the height of water‐proof coal (rock) pillar is calculated as 91.08 m when mining upper and lower groups and 105.46 m when mining all coal seams at the same time. According to UDEC numerical simulation results, the height of water‐proof coal (rock) pillar is 56.08 m when mining upper and lower groups and 86.36 m when mining all coal seams at the same time. Comparing the results of theoretical calculation and numerical analysis, the maximum value is selected as the final result, and the reasonable water‐proof coal (rock) pillar height is determined to be 105.46 m.