Abstract
A thin coal seam mined as a protective coal seam above a gas outburst coal seam plays a central role in decreasing the degree of stress placed on a protected seam, thus increasing gas permeability levels and desorption capacities to dramatically eliminate gas outburst risk for the protected seam. However, when multiple layers of coal seams are present, stress-relieved gas from adjacent coal seams can cause a gas explosion. Thus, the post-drainage of gas from fractured and de-stressed strata should be applied. Comprehensive studies of gas permeability evolution mechanisms and gas seepage rules of protected seams close to protective seams that occur during protective seam mining must be carried out. Based on the case of the LongWall (LW) 23209 working face in the Hancheng coal mine, Shaanxi Province, this paper presents a seepage model developed through the FLAC3D software program (version 5.0, Itasca Consulting Group, Inc., Minneapolis, MI, USA) from which gas flow characteristics can be reflected by changes in rock mass permeability. A method involving theoretical analysis and numerical simulation was used to analyze stress relief and gas permeability evolution mechanisms present during broken rock mass compaction in a goaf. This process occurs over a reasonable amount of extraction time and in appropriate locations for comprehensive gas extraction technologies. In using this comprehensive gas drainage technological tool, the safe and efficient co-extraction of thin coal seams and gas resources can be realized, thus creating a favorable environment for the safe mining of coal and gas outburst seams.
Highlights
In China, more than 50% of coal seams are high gas-containing coal seams, and high outburst mines account for 44% of all coal mines in the country [1,2,3]
In combining methods of theoretical analysis, numerical simulation, and field application, this paper examines gas permeability evolution mechanisms and comprehensive gas drainage paper examines gas permeability evolution mechanisms and comprehensive gas drainage technologies technologies involved during the thin coal seam mining of coal mines in Shaanxi Province, China
Stress gas has successfully andis especially has regarded as a coal seam gas exploitation and outburst prevention technology
Summary
In China, more than 50% of coal seams are high gas-containing coal seams, and high outburst mines account for 44% of all coal mines in the country [1,2,3]. Theoretical studies and field practice have shown that mining a protective seam can gas extraction efforts to have limited effects prior to coal seam mining [7,8,9]. Theoretical studies release stress and can improve the gas permeability of a coal seam, which can in turn enhance and field practice have shown that mining a protective seam can release stress and can improve gas the extraction and prevent coal and gas outbursts [10,11,12,13,14]. In combining methods of theoretical analysis, numerical simulation, and field application, this paper examines gas permeability evolution mechanisms and comprehensive gas drainage paper examines gas permeability evolution mechanisms and comprehensive gas drainage technologies technologies involved during the thin coal seam mining of coal mines in Shaanxi Province, China.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
