Citation

Yang Z, Cheng Z, Liu Y, Wang H, Yang P, Sun F. China Saf. Sci. J. 2020; 30(5): 66-73.

Copyright

(Copyright © 2020, China Occupational Safety and Health Association, Publisher Gai Xue bao)

DOI

10.16265/j.cnki.issn1003-3033.2020.05.011

PMID

unavailable

Abstract

In order to reveal influence of multiple mining of coal seam group on gas extraction efficiency of cross-layer borehole in bottom extraction roadway, Flac software was used to simulate and study pressure relief characteristics of roadway roof and expansion features of plastic area of surrounding rock during downward mining of No. 3, 4, 5 coal seam of Shaqu No.2 mine. Then, site measurement was conducted for borehole gas extraction efficiency. The results show that pressure relief degree of No.3 coal seam mining is more than 59%, indicating the most obvious pressure relief effect and largest increase rate of gas extraction concentration and purity. Along with increase of mining times, pressure relief degree and increase rate decrease. During mining of the No.4 coal seam, plastic area of surrounding rock reaches 3. 1 m, exceeding borehole sealing length, and amount of gas mixture in borehole begins to increase gradually. As mining times increase, plastic area and gas mixture increase. Meanwhile, gas extraction concentration and purity of cross-layer borehole show a gradual downward trend. © 2020 China Safety Science Journal. All rights reserved.

Language: zh