Study on pre-drainage seam gas technology with borehole drilled along seam in outburst and soft mine

In order to solve the difficult issues which the drilling depth is often less than the design depth and resulting coalface often pre-pumping "blank area" in the soft and Outburst Coal Seam drilling construction, which uses conventional drill after drill hole often results seams seriously collapse and Under drainage pipe in the borehole is difficult, ZYW-3000-type coal linkage with full hydraulic drilling rigs is selected, whose drill pipe is made of high strength large lead overall spiral, which increases the rate of drilling into the hole, and increases the length of the down tube drilling, and has increased gas extraction space and extraction cycle, improving the effect of the gas extraction. The drill pipe outside diameter is 73 mm, the length of each is 1 m. The depth of drill hole is 100 m; the length of pre-down tube is 100 m, the back file apart from the hole is 1.5-2 m, the middle section is filled with cement paste.