Study On Coal Pillar Size In Fully Mechanized Caving Face Of No.2 Mining District Of Sima Coal Industry

This paper takes the 1208 fully mechanized caving face in the second mining area of Sima Coal Industry Co.,Ltd.as the specific research background,and comprehensively uses laboratory test,field measurement,theoretical analysis,numerical simulation,industrial test and other methods to solve the problem of leaving coal pillars in the working face.Based on the problem,the optimization of the size of the section coal pillar was studied,and the following research conclusions were obtained:(1)Through the laboratory SANS test machine,the compressive,tensile and shear tests were carried out,and the mechanical parameters of coal and rock in the top and bottom of No.3 coal seam were obtained.(2)The field test results before the coal pillar size is optimized are: the maximum separation of the 1208 transportation road roof,coal pillar and solid coal is small,the anchor has a good anchoring effect,and the surrounding rock remains basically stable,indicating the area.The section coal pillar has room for further optimization.(3)According to the specific parameters of the fully mechanized caving face of No.3 coal seam of Sima Coal Industry,and the on-site field investigation,the relevant data collection,using empirical formula method,load estimation method,elastic core theory calculation method,combined with the field measured lateral support pressure part,The section coal pillar size can ensure the stability of the roadway,ensure the normal production of the working face,reduce the waste of coal resources and facilitate the on-site construction,and determine the reasonable size of the section coal pillar is 25 m.(4)According to the numerical simulation under different coal pillar size conditions,under the premise of ensuring mine safety production,combined with the current green mining management concept,improve the utilization rate of coal resources and increase the economic benefits of enterprises,determine the section coal pillars.The size of 25 m is reasonable,which can ensure the stability of the mining roadway and facilitate the normal mining of the working face.(5)Through the analysis of the industrial test of the 1209 working face in the second mining area,it is found that the surface displacement of the roadway is small,there is no obvious surrounding rock deformation,no crushing area is found in the section coal pillar,the stability of the roadway is good,and the section coal pillar can Play a very good supporting role.As the working face advances,the change trend of the bolt(cable)is obvious,and the overall trend is upward.The maximum force is 140 KN and 390 KN respectively.The maximum force of the bolt exceeds the yielding load of the rod,reaching 90.9 of the rod body breaking load;the maximum force of the anchor cable is 94.1% of its breaking load,and it has a certain margin.It fully exerts the high-strength support of the bolt(cable)to meet the safety production requirements,using the original anchor rod(cable)The parameters are to ensure the normal production of the working surface,it is reasonable to leave a section of coal pillars at a size of 25 m.