Research And Application Of The Key Technology Of Kicking Gob Mining In The Fully Mechanized Caving Face Of The Extra Thick Coal Seam In Hulonggou Mine

During the mining of the overlying extra-thick coal seam,it is very likely to induce the instability of the coal pillar left in the pillar goaf of the underlying coal seam under certain conditions,which will affect the safety of the mining of the overlying extra-thick coal seam.Based on the research background of the stability of the remaining coal pillars in the underlying pillar goaf under the influence of the overlying extra-thick coal seam caving mining in Hulonggou Mine,this thesis discusses the deformation and damage characteristics of the remaining coal pillars in the 8# coal room and pillar goaf during the caving mining of the 5# coal seam.By means of theoretical analysis,field measurement and numerical simulation,the thesis studies the influence of the stability and deformation and damage of the room and pillar type remaining coal pillar in the underlying coal seam on the mining of the overlying 81517 fully mechanized caving face,grasps the development characteristics of the fracture zone after the mining of the underlying 8 #coal seam,reveals the deformation and damage law of the rock pillar in the lower strata under the influence of the mining of the 5# coal seam,and then puts forward the feasibility plan and safety assurance measures for the mining of the 5# coal seam.The research results show that the key factors affecting the safety of the overlying extra-thick coal seam in Hulonggou Mine mainly include: interval and mining height,mining method,coal and rock mass properties,coal seam dip angle,fault,mining time,etc;Through theoretical analysis,calculation and numerical simulation research,it is considered that under the condition of room and pillar mining of 5# coal seam,the influence of 5# coal seam on 5# coal seam is not obvious due to the existence of several thick and high strength rock strata between 5# and 8#coal seams;During the mining of 5#Coal Seam,all coal pillars in the goaf of 8# Coal Seam were not completely damaged,which can effectively maintain the stability of the strata between the coal seams;The technical measures for safety protection during the period of the goaf mining have been formulated and industrial tests have been carried out.During the goal-pushing mining of 81517 fully mechanized top-coal caving face,the deformation and damage of surrounding rock of the mining roadway and the abnormal occurrence of harmful gases such as gas are all within the controllable range,which has no adverse impact on the safety production of the working face;The successful application of the industrial test of pushing out mining in 81517 fully mechanized caving face provides technical reference for the practice of pushing out mining under similar mining conditions in this mine.This thesis has 59 figures,19 tables and 136 references.