Minging Technology Of Coal Pillar Working Face In Juji Coal Mine

The driving length of downhill coal pillar is 250 m,width is 270 m,and two sides of coal pillar are isolated face.In order to solve the tension of mining and succession,it is necessary to prepare for safe mining of isolated coal pillar face resources.Therefore,the mining of coal pillar face needs to carry on the technical research to the three difficult problems,such as the over-air roadway,the reasonable stopping line and the along-air roadway.Based on laboratory coal-rock mechanics test,site surrounding rock structure detection,this paper analyzes the main difficulties affecting safe and efficient mining face.Mechanical model of coal-column working face is constructed,the breaking process is analyzed,stress distribution of different driving length and deformation failure rule of plastic zone are simulated and studied.Characteristics of deformation and failure degree of surrounding rock in working face roadway are simulated,and position of stopping line and supporting technology along goaf roadway are determined reasonably.The following research results were obtained:1)Aiming at the problem of coal pillar face over-air roadway,the characteristics of coal pillar stress change in coal pillar face over-air roadway are analyzed.In the process of working face advancing to abandoned roadway,the stress change shows the change trend of "increasing-increasing-decreasing sharply ",the stress distribution curve shows the distribution of " leading-distribution-saddle-sharpening ",the mechanical model of coal pillar face over-air roadway is constructed,and the breaking process of working face over-air roadway roof is analyzed.Calculated by mechanical balance the minimum supporting resistance is 6.7 MN.2)According to the different types of coal pillar face,the design scheme of overair roadway is put forward.For roof-air roadway,the support is in the state of supporting abandoned roof,the thickness of safe rock pillar is calculated as 4 m,the stress and plastic zone of working face and air roadway are simulated and analyzed.3)The theoretical calculation and numerical simulation show that the reasonable stop line is 40 m from the right from the right roadway,the deformation characteristics and coal roadway are analyzed,and the optimization scheme of roadway reinforcement support is put forward.The roof deformation is 49 mm,the left side deformation is 158 mm,and the stability is good.There are 69 figures,4 tables and 80 references in this paper.