Optimization of concurrent mining and reclamation plans for single coal seam: a case study in northern Anhui, China

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

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Uneven stress and permeability variation of mining-disturbed coal seam for targeted CBM drainage: A case study in Baode coal mine, eastern Ordos Basin, China

Fuel ◽

10.1016/j.fuel.2020.119911 ◽

2021 ◽

Vol 289 ◽

pp. 119911

Author(s):

Chao Xu ◽

Gang Yang ◽

Kai Wang ◽

Qiang Fu

Keyword(s):

Coal Seam ◽

Coal Mine ◽

Ordos Basin ◽

Permeability Variation

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Informal and Nonformal Adult Learning in the Coal Seam Gas Protests: Mobilizing Practices and Building an Environmental Justice Movement for Change

Adult Education Quarterly ◽

10.1177/07417136211005370 ◽

2021 ◽

pp. 074171362110053

Author(s):

Tracey Ollis

Keyword(s):

Adult Learning ◽

Coal Seam ◽

Environmental Justice ◽

Water Supply ◽

Case Study Research ◽

Coal Seam Gas ◽

The Public ◽

Theory Of Practice ◽

The Earth

This case study research examines informal adult learning in the Lock the Gate Alliance, a campaign against mining for coal seam gas in Central Gippsland, Australia. In the field of the campaign, circumstantial activists learn to think critically about the environment, they learn informally and incidentally, through socialization with experienced activists from and through nonformal workshops provided by the Environmental Nongovernment Organization Friends of the Earth. This article uses Bourdieu’s “theory of practice,” to explore the mobilization of activists within the Lock the Gate Alliance field and the practices which generate knowledge and facilitate adult learning. These practices have enabled a diverse movement to educate the public and citizenry about the serious threat fracking poses to the environment, to their land and water supply. The movements successful practices have won a landmark moratorium on fracking for coal seam gas in the State of Victoria.

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Comprehensive technical support for safe mining in ultra-close coal seams: A case study

Energy Exploration & Exploitation ◽

10.1177/01445987211009390 ◽

2021 ◽

pp. 014459872110093

Author(s):

Wei Zhang ◽

Jiawei Guo ◽

Kaidi Xie ◽

Jinming Wang ◽

Liang Chen ◽

...

Keyword(s):

Coal Seam ◽

Technical Support ◽

Surrounding Rock ◽

Coal Seams ◽

Deformation Control ◽

Hard Roof ◽

Working Face ◽

Close Coal Seams ◽

Safe Mining

In order to mine the coal seam under super-thick hard roof, improve the utilization rate of resources and prolong the remaining service life of the mine, a case study of the Gaozhuang Coal Mine in the Zaozhuang Mining Area has been performed in this paper. Based on the specific mining geological conditions of ultra-close coal seams (#3up and #3low coal seams), their joint systematic analysis has been performed, with the focus made in the following three aspects: (i) prevention of rock burst under super-thick hard roof, (ii) deformation control of surrounding rock of roadways in the lower coal seam, and (iii) fire prevention in the goaf of working face. Given the strong bursting tendency observed in upper coal seam and lower coal seam, the technology of preventing rock burst under super-thick hard roof was proposed, which involved setting of narrow section coal pillars to protect roadways and interleaving layout of working faces. The specific supporting scheme of surrounding rock of roadways in the #3low1101 working face was determined, and the grouting reinforcement method of local fractured zones through Marithan was further proposed, to ensure the deformation control of surrounding rock of roadways in lower coal seams. The proposed fire prevention technology envisaged goaf grouting and spraying to plug leaks, which reduced the hazard of spontaneous combustion of residual coals in mined ultra-close coal seams. The technical and economic improvements with a direct economic benefit of 5.55 million yuan were achieved by the application of the proposed comprehensive technical support. The research results obtained provide a theoretical guidance and technical support of safe mining strategies of close coal seams in other mining areas.

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