Hole-sealing and Gas Concentrating Technique for Bedding Gas Extraction Drilling Hole and Its Application

We study the hole-sealing process and hole-sealing material for bedding gas drainage borehole, and research and develop the hole-sealing material with high expansibility, strong liquidity and moderate intensity and the hole-sealing technique with pressure grouting of "two sealing and one grouting". We also calculate reasonable sealing depth of the gas drainage borehole in different drainage areas by numerical modeling and the testing of the sealing quality. We form hole-sealing and gas concentrating technique for bedding gas drainage borehole. This sealing technology had been tested at Liyazhuang Coal Mine in Shanxi province, within 80 days test period, there is no significant attenuation phenomenon of gas density in drilling hole sealed by new hole-sealing material.