Research on optimization of gas drainage height with high-level boreholes under multiple coal seam conditions

Abstract

In order to solve the problem of the uncertainty of the height when high-level boreholes are used to extract pressure relief gas from multiple sources under the condition of multiple coal seams, the isotope and gas composition of methane desorbed from the coal cores of the mining seams and their adjacent seams, as well as the methane collected from the methane drainage boreholes at different heights in the gobs were measured. The source and proportion of gas drainage from high-level boreholes at 607 working face of Tenghui Mine in Shanxi Province were calculated, and the optimal height range for gas drainage from high-level boreholes was determined. The optimal position of high borehole and low borehole to effectively control the gas in this coal seam and the adjacent layer below is determined, that is, 7.9 m to 14.2 m away from the roof of mining coal seam. And the best position of high borehole to effectively control the gas in this coal seam and the upper adjacent layer, that is, 42.1 m to 45.4 m away from the roof of mining coal seam.

Keywords

• multiple coal seams
• high-level borehole
• gas drainage
• carbon and hydrogen isotope