Study on hole sealing of pre-drainage boreholes in infection zones of nearby coal face mining
FAN Zhengxing
Abstract：In order to solve the low drained gas concentration problem from the gas pre-drainage borehole in the underground mine of Yuwu Coal Mining,an investigation analysis was conducted on the pre-drained gas concentration of the gas pre-drainage boreholes in different mine gateway of the mine.The paper held that the mining influences of the neighboring coal mining face would have high influences to the drained gas concentration from the gas pre-drainage borehole in the mine gateway.A method combined with the theoretical analysis and the site measurement was applied to study the pre-drained low gas concentration causes of the gas pre-drainage borehole in the mining influence area.Within the mining influence area,with the influence of the stress increased,the thickness of the rock released ring in the surrounding rock of the mine roadway would be increased.During the sealing of the pre-drainage borehole,due to the grouting section of the borehole sealed could not avoid the rock released ring in the surrounding rock,the grouting liquids were leaked along the cracking and thus the borehole sealing was failure.According to the mining influence area,a new borehole sealing method was provided to increase the borehole sealing depth and to reduce the borehole sealing depth.The practices showed that with the application of the new borehole sealing method,the drained gas concentration from the gas pre-drainage borehole in the mining influence roadway was obviously increased,the gas drainage volume fraction of near 80％ boreholes was over 30％ and the boreholes with the volume fraction over 30％ were 10 times higher than the previous boreholes.
Keywords：seam gas pre-drainagerock loosened circlemining influencesgas drainage
Publication Date：2017-01-01