Laws of overburden movement and mine pressure behaviors in 10 m super-high working face under thick and hard roof

MA Rongshan; XU Gang; LIU Xiaogang; LIN Xingyu; REN Jianchao

doi:10.11799/ce202411012

Abstract：Aiming at solving the problem of strong mine pressure in extra thick mining face buried shallowly under thick and hard roof,based on support resistance and in-situ microseismic overlying rock monitoring data,the mine pressure and overburden movement in Caojiatan 10 m super-high mining face were studied.The results show that the initial weighting interval of the main roof of the mining face is 49.35 m,the average periodic weighting interval is 21.89 m,and the average dynamic load coefficient is 1.49.The working face has the phenomenon of"intense and mild periodic weighting".During the intense weighting,the weighting interval increases significantly.During the non-weighting period,the working resistance of the support increases insignificantly,but significantly during the periodic weighting.The active column of the support has obvious shrinkage,especially during the intense weighting period,the average and maximum shrinkage of the column reach 686.12 mm and 1321.35 mm,respectively.It has the characteristics of long weighting interval,long weighting duration,frequent weighting,strong dynamic load mine pressure and severe rib spalling.The active area of microseismic events is along the working face dip,0～130 m away from the center of the working face,and the peak area is in the 110～130 m area.At 40～60 m above the coal seam roof,the microseismic events have low frequency but high energy,which is the dominant rock formation of strong mine pressure.The spatial and temporal distribution of microseismic events coordinates with the law of mine pressure.High-energy microseismic events usually occur before the mine pressure behaviors of the working face and have good correlation with periodic weightings,which is reliable for the prediction of mine pressure.The cutting and falling of high strata before the face support is the important reason for the obvious pressure increase and rib spalling during the intense weighting.