Ground control of narrow coal pillar in gob side entry driving with fully mechanized top coal caving mining in extra-thick coal seam

In view of the problems of large roadway deformation and serious coal loss caused by gob side entry driving with wide coal pillar in fully mechanized top coal caving mining of extra-thick coal seam in Tongxin Mine,this paper puts forward the technology of narrow coal pillar roadway protection. Taking 8305 working face of Tongxin Coal Mine as engineering background,combined with internal and external stress field theory and limit equilibrium zone theory,it is concluded that the distance between the basic roof fracture line and the goaf is 3 m,and the narrow coal pillar width is 6 m. Based on the analysis of the difficulties in ground control of narrow coal pillar roadway in extrathick coal seam,the paper puts forward the strong combined support technology of roof with high strength and high prestress bolt support system,combined anchor cable support system and multi anchor cable steel belt truss system,surrounding rock control technology of strong bolt support system and shotcrete reinforcement for coal pillar side,as well as borehole pressure relief treatment of solid coal slope and support of strong bolt and anchor cable. The system controls the surrounding rock stability of roadway driving along goaf in the extra-thick coal seam. The field practice shows that the control effect of 5305 roadway surrounding rock is good,which can realize the control of surrounding rock stability of roadway driving along goaf in the extra-thick coal seam.