Gas Control Effect and Determination on Drainage Location of Directional High Level Long Borehole

In order to effectively control the upper corner gas in a goaf, according to the status that directional high level long borehole was applied to drainage the upper corner gas in No. 16041 Coal Mining Face in Jiulishan Mine, UDEC software was applied to simulate the plastic zone in the overburden strata above a coal minin g face. In combination with a site experiment, an optimum drainage location of the directional high level long borehole determined should be within distance of 13 ~ 25 m to the roof. The result showed that an average volume fraction of the upper corner gas in the coal mining face was reduced from 0.78% to 0.31% and the advancing speed of the coal mining face was improved from3. 6m/dto4.8 m/ d and was increased by 1. 33 times, which could ensure safety mining.