During overlying rock strata being fractured, the surfacegas drainage boreholes may be damaged due to ground movement.
在长壁工作面通过的过程中，地面垂直钻孔可能随岩层移动而发生破坏。
2
Test results of surfacegas extraction technology from boreholes in the goaf in Zhangbei Coal Mine, Huainan Mining Group are introduced in the paper.
本文介绍了淮南矿区张北矿地面钻孔抽采采空区瓦斯技术的试验成果。
3
This paper elucidated the theoretical basis for controlling the fluidization parameters by calculating the SGV surfacegas velocity in he LLDPE reactor.