Research on the effect of coal seam inclination on gas migration channels at fully mechanized coal mining face
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ISMSSE 2018
Research on the effect of coal seam inclination on gas migration channels at fully mechanized coal mining face Pengxiang Zhao 1,2 & Risheng Zhuo 1
&
Shugang Li 1,2 & Chun-Hsing Ho 3 & Haifei Lin 1,2 & Hui Liu 1
Received: 6 January 2019 / Accepted: 27 August 2019 / Published online: 16 September 2019 # Saudi Society for Geosciences 2019
Abstract To investigate the mechanical evolution progress of mining-induced pressure-relief gas migration channel in overlying strata fissure at fully mechanized mining working face, physical similarity simulation tests were conducted to experimentally and numerically evaluate the mining process of a coal mine in Heshun, Shanxi Province. The profiles of the gas migration channels were mathematically modeled based on the theory of elliptical zone of mining-induced fissure, using the dip angle of coal seams of working face as the key parameter. The impacts of dip angle of coal seams on the evolution of pressure-relief gas migration channel in overlying strata fissure at the main mining working face were analyzed. Results suggested that the increase in the dip angles of coal seams could reduce the height of the three zones and could expand the average weighting interval; the gas migration channels were formed at lower positions in the overlying strata, resulting in the lower height, width, caving angle, and range; in addition, with the increase of the dip angle, the segregation and propagation rates of the gas migration channel gradually increased, and the fractal dimensions of coal seams are measured in between 1.68, 1.69, and 1.71, displaying an increasing trend. On-site high-level boreholes were arranged to validate the laboratory results. Based on the monitoring, the gas extraction through the high-level borehole field reached 49.94~89.88% of the total gas emission. In general, the average concentration of gas in the upper corner is maintained below 0.27% and the average concentration of gas in the return airway is maintained below 0.32% so as to ensure a safe and an efficient mining environment. The study contributes to the theoretical basis for identification of pressure-relief gas enrichment areas in overlying strata under the effect of dip angle of coal seams. Keywords Mining-induced overlying strata fissure . Gas migration channels . Angle of coal seams . Mining working face . High-level boreholes
Introduction China has large coal reserves, which leads to one of the biggest production and consumption of coal in the
This article is part of the Topical Collection on Mine Safety Science and Engineering * Risheng Zhuo [email protected] 1
School of Safety Science and Engineering, Xi’an University of Science and Technology, Xi’an 710054, Shaanxi, China
2
Key Laboratory of Western Mine Exploitation and Hazard Prevention with Ministry of Education, Xi’an 710054, Shaanxi, China
3
Department of Civil Engineering, Northern Arizona University, Flagstaff, AZ 86011, USA
world. Coal accounts for 77% and 66%, respectively, in production and consumption of primary ene
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