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Minerals 2017, 7(9), 166; https://doi.org/10.3390/min7090166

Impact of Coalbed Incidence Angle on Methane Enrichment Zone in Longwall Gob

1
College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China
2
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221008, China
3
Green Mining Engineering Technology Research Center of Shanxi Province, Taiyuan 030024, China
4
State Key Laboratory of Coal and CBM Co-mining, Jincheng 048000, China
5
Western Australian School of Mines, Curtin University, Kalgoorlie, WA 6430, Australia
*
Author to whom correspondence should be addressed.
Received: 13 August 2017 / Revised: 1 September 2017 / Accepted: 4 September 2017 / Published: 11 September 2017
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Abstract

To control methane emissions in gob into longwall working faces, it is necessary to understand the distributions of methane enrichment zones (MEZ) around mined coal seams with different incidence angles. In this paper, FLAC3D software is used to calculate the three-dimensional stress distributions in MEZ in gobs with coalbed incidence angles ranging from 0° to 50°. The results show that MEZ consistently exhibit a “hexagon” shape, and rotate in a clockwise direction as the coalbed angle increases. The MEZ range above the mined seam is larger than that below the mined seam. As the coalbed angle increases, the MEZ range in the roof decreases, while the MEZ range in the floor increases. The MEZ height increases significantly as the coalbed angle increases. The MEZ widths in coal pillars of gobs increase slightly as the coalbed angle increases. The methane concentration increases exponentially as the height in the MEZ increases. The surface borehole bottoms located relatively higher in the MEZ can drain methane with a higher concentration and flow rate, as verified by a field test in the Pansan mine, China. View Full-Text
Keywords: coal mine; longwall gob; stress distribution; methane enrichment zone; methane drainage coal mine; longwall gob; stress distribution; methane enrichment zone; methane drainage
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Hu, S.; Zhang, A.; Feng, G.; Guan, S.; Guo, X.; Li, C.; Xu, G. Impact of Coalbed Incidence Angle on Methane Enrichment Zone in Longwall Gob. Minerals 2017, 7, 166.

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