摘要
Abstract
In the mining of the working face,the integrity of the hard roof is good,and the self-stabilizing ability is strong.After mining,a large area of suspended roof will be formed,which seriously threatens the safety of personnel and equipment in the working face.In order to realize safe mining,the research on roof cutting and pressure relief technology of hard roof was carried out in No.21902 Face of Xinyuan Mine.By comparing the advantages and disadvantages of three different roof cutting methods,combined with the geological conditions of the coal seam,the hydraulic fracturing roof cutting method was determined.On the basis of determining the height and angle of roof cutting,27 fracturing boreholes were designed and arranged,with a length of 15 m,an elevation angle of 45 ° and a vertical height of 10.6 m.Field application showed that the fracturing time of each point was about 30 min,and the pressure range was 13.3～21.8 MPa.Borehole peep showed that there were obvious cracks in limestone,and the initial pressure step of the fracture zone parallel to the roadway direction was reduced by 67.5％,and the ideal fracturing effect was achieved.关键词
坚硬顶板/水力压裂/石灰岩顶板/钻孔窥视Key words
hard roof/hydraulic fracturing/limestone roof/borehole peep分类
矿业与冶金
