Study On The Technology Of Increasing Recovery Ratio Of 2206 Fully Mechanized Caving Face In Changcun Coal Mine

In recent years,the state has reformed the coal industry,and closed many small and medium mines,resulting in a decline in coal production.In addition,due to the increase of mining depth and the influence of various complex geological conditions,how to achieve high production and efficiency of coal has become the key point of coal industry research.Therefore,this thesis studies how to improve the recovery ratio of fully mechanized caving face,taking 2206 fully mechanized caving face in Changcun Coal Mine as the research background(1)The influencing factors of recovery ratio of 2206 fully mechanized caving face in Changcun Coal Mine are systematically analyzed,including process loss,initial mining loss,final mining loss,face-end mining loss and coal pillar loss.The coal losses caused by various loss factors are calculated respectively.The caving property of top coal is also analyzed.(2)The first collapse step of 2206 mining face is predicted by studying the law of rock pressure appearance of similar mining face.In order to reduce the coal losses during the initial mining period,the support relief technology is put forward.Through theoretical analysis and numerical simulation,it is concluded that the first collapse step of top coal is reduced and the coal production during the initial mining period is increased by support relief technology.(3)In order to reduce coal losses during the final mining period,hydraulic fracturing roof cutting technology is put forward.According to the actual situation of 2206 fully mechanized caving face in Changcun Coal Mine,the arrangement scheme of fracturing drill holes is designed.Hydraulic fracturing roof cutting destroys the "cantilever beam" structure of the roof above the stop-mining line,then reduces the influence of advance abutment pressure,finally reduces the width of roadway pillar,and improves the coal production during the final mining period.(4)In view of the waste of coal resources caused by the excessive width of coal pillars in the section,theoretical analysis and numerical simulation are carried out on the reasonable width of coal pillars in the section.The results show that the reasonable width of coal pillars in the section is 20 m.By reducing the width of coal pillar in the section,the coal pillar loss is reduced and the recovery ratio is improved.(5)The industrial tests of support relief,hydraulic fracturing roof cutting and reasonable width of coal pillar were carried out in 2206 fully mechanized caving face of Changcun Coal Mine.Finally,the coal production of 2206 mining face increased by 77081 ton,and the recovery ratio increased by 5.34%.