Study on the development characteristics of overburden water flowing fracture height in No.8 coal seam of Baode Coal Mine

Coal green mining is the mainstream direction of coal mining in the future, and the protection of water resources and surface ecology at the same time of coal mining will be one of the main directions of research.Combined with the storage characteristics and mining conditions of the 8^# coal seam of Baode Coal Mine, in view of the serious impact of mining subsidence on surface buildings (structures) caused by underground mining in the mining area, the theoretical analysis method is used to predict the height of the water flowing fracture zone in the goaf area, and the drilling method was used for actual measurement and verification.The results show that there are three key stratum in the 8^# coal seam of Baode Coal Mine, in which the main key stratum is located at 103 m from the coal seam, and the theoretical height is 103 m by using the calculation model of water flowing fracture based on the key stratum, and the theoretical height of water flowing fracture obtained by traditional empirical formula is 41.2-61.8 m and 57.8-87.7 m.By analyzing the variation of borehole water level, flushing fluid leakage and borehole peeping results, the development height of water flowing fracture is 106 m.It can be seen that the key stratum discrimination method is more applicable than the empirical calculation method, providing reliable theoretical support for the prediction of overburden subsidence and guide height in Baode Coal Mine.