Preliminary study on coal bump mechanism induced by co-movement of higher strata and coal bump control method between two mines

In the mining process of adjacent mines,each other’s disturbance is obvious and coal bump disasters occur frequently. In order to study the mechanism of coal bump induced by mining disturbance between two adjacent working faces in two adjacent mines and the coordinated control method of coal bump in two working faces under the control of huge thick conglomerate and thrust fault,taking the 13230 face of Gengcun Mine and the 21121 face of Qianqiu Mine in Yima mining area as an actual engineering background,this paper analyzes the surface subsidence,coal bump be- havior and support pressure during the 13230 face’s mining operation,the borehole stress of cable-car dip in the east of the 21121 working face,and the height of micro-seismic events and in-situ stress distribution of two mines’ bounda- ry area. The results show that the asymmetric T-shaped spatial structure is formed in the asynchronous mining process of the two faces,under the condition of coal pillar and higher massive conglomerate in the mine-boundary area,which occurs a prying phenomenon similar to the leverage—high-level strata above goaf side induces an overall uplift move- ment of the corresponding strata above later mining side. Co-movement effect of high-level strata disturbs the vertical stress environment of later mining face and the disturbance range is limited. The vertical stress of the 13230 face is rel- atively low at the beginning of mining and high horizontal stress of fault activation causes typical bump accident with the horizontal slip of coal body. As the increase of mining length of the 13230 face,the intensity and frequency of coal bump of horizontal direction decrease obviously but high proportion in vertical direction. Based on the results of engi- neering and laboratory test,the synergistic prevention method of “ chain-weakening and consumption-increasing” with the core of cutting higher sandstone-conglomerate interbedding and the “ energy-absorbing and structure-stabilizing” with the core of high-strength filling in goaf is proposed to achieve the coordinated control of coal bump between two mines. With China’ s coal mines gradually turning into intensive mining and deep mining,the phenomenon of stress disturbance between multiple working faces caused by higher overburden’s co-movement will exist for a long time. The coal bump prevention method and technology aimed at weakening co-movement effect of overburden structure is the development trend of cooperative prevention among multi-working faces in single mine and even large mining area in the future.