The invention relates to a construction method for a
coal mine downhole mining gas extraction roof plate
pitch-up through stratum directional hole. By using a
drill site in a tunneled air inlet roadway of a working face adjacent to a working face to be mined, equipment such as
pilot directional
drill tools and
impact composite reaming
drill tools, a multi-stage revolving reaming process, a sliding
directional drilling process, a composite
directional drilling process and an
impact composite reaming process, the roof plate
pitch-up through stratum directional hole is obtained. The roof plate
pitch-up through stratum directional hole enters a roof plate mining
fissure zone and a separation area in advance and extends for a long distance at a large
diameter. After drilling construction and during
recovery of the working face to be extracted, an upward fracture formed in a roof plate stratum under the influence of mining communicates with the roof plate pitch-up through stratum directional hole, gas generated during mining enters the roof plate pitch-up through stratum directional hole, and therefore extraction and use of mining gas is realized. The defects that an existing mining gas extraction drilling hole is small in aperture, the extension distance of a
fracture zone is short, the drilling efficiency is low, the cost is high, and the construction period is long are overcome, and the mining gas extraction effect is improved.