Abstract：Wangjialing coal mine is a typically high gas coal mine caused by high strength mining in low gas coal seam, and it is difficult to drain gas from the coal seam due to the poor gas content and permeability of coal seam. In order to study the technical parameters of highly oriented level boreholes suitable for pressure-relief gas drainage in Wangjialing mine, the gas drainage process parameters such as gas concentration, pure gas flow rate and so on were investigated in fully mechanized top coal caving face 12318, and the relationship between key parameters such as level location on vertical, horizon offset distance from return airway and drainage effect were analyzed. Based on coal seam roof mechanical parameters, the heights of roof caved zone and fractured zone were calculated by empirical formula, whose ranges were 19. 11 ~ 24. 10 m and 57. 06 ~ 74. 86 m respectively. The analysis of drainage effect showed that drainage pure gas flow value of the borehole increased with the increase of drilling horizon in the same drill site, while the value increased with the decreasing of the horizon offset distance from return airway; the drainage pure gas flow value from the highest tow borehole was more than 70% of the total of the drill site. When boreholes vertical height range was 25 ~ 41 m, gas drainage effect for reduce gas concentration of top corner was significantly better than those boreholes of horizon height less than 20 m.

Keyword：highly oriented level borehole;level location on vertical;horizon offset distance from return airway;pressure-relief gas drainage;fractured zone;