CFD Simulation Study on Treating Gas in Early Stage of Gas Production by Post-high Drainage Vertical Holes

In order to solve the problem of high difficulty and high cost in the construction of post-false high drainage roadway, a new gas control scheme is proposed to replace the post-false high drainage roadway with post-high vertical drainage hole. In order to optimize the parameters of post-high vertical drainage hole, a numerical model was established based on 15201 working face of Xindadi Coal Mine, and the numerical simulation was carried out. The reasonable layout parameters of the post-high vertical drainage hole of 15201 working face of Xindadi Coal Mine were obtained, i.e., the distance between the vertical drainage hole and the cutting hole coal wall was 10 m, and the distance between the vertical drainage hole and the return airway was 10 m. In order to investigate the gas extraction effect of post-high vertical drainage hole after the initial mining period, we carried out field measurement of gas mixture flow and gas concentration in the drainage pipeline of high drainage roadway. The measured results show that during the initial pressure of the working face, the amount of gas extraction increased sharply in the post-high drainage hole, and a good gas extraction effect was achieved in the initial production period, which solved the problem of gas over-limit in the initial production period of 15201 working face.