Analysis on Major Borehole Sealing Methods of Mine Gas Drainage Boreholes

With an analysis on the major borehole sealing methods for mine gas drainage in China, it was found that an improper study on the crack development s cope of the surrounding rock along the borehole, the irrational selection of the borehole initial sealing depth and borehole sealing length, the low grouting pressure, the polyurethane and cement mortar as well as other sealing material with ineffective sealing of cracks in surrounding coal and rock along the borehole would be the main C auses of irational gas drainage borehole sealing effect in China coal mine. A technical access to improve the borehole sealing effect of the"two sealing and one groutin g' pressurized borehole sealing method was provided, including the study on the crack development time effect features of the surrounding rock along the borehole und er the condition of the multi damages, the determination on the rational initial sealing depth of the gas drainage borehole and the length of the sealing section between t he two ends, the proper grouting material applied and the increase of grouting pressure.