Coal seam groups are widely distributed in mining areas of different regions in China, especially closely spaced coal seam groups (Wang et al. 2013).Selecting a coal seam with the optimal reliability factor as the first mining seam is necessary to achieve safe and highefficiency mining due to the diversified conditions of coal seams during mining (Wang et al. 2017; Li et al. 2021; Wu et al ...
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COAL MINING METHODS Surface Mining In surface mining, the ground covering the coal seam (the overburden) is first removed to expose the coal seam for extraction.
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Owing to the exhaustion of shallow coal resources, deep mining has been occupied in coal mines. Deep buried coal seams are featured by the great ground stress, high gas pressure, and low permeability, which boost the risk of gas disasters and thus dramatically threaten the security about coal mines. Coal seam gas pressure and gas content can be decreased by gas extraction, which is the primary ...
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% methane, whereas gas drained from the seam before mining can contain 60% to more than 95% methane depending on the presence of other gasses in the coal seam. Gas drained from fractured formations above mined seams (gobs), on the other hand, may contain 3095% methane depending on the locations of the boreholes and other
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History Coalbed methane grew out of venting methane from coal seams. Some coal beds have long been known to be "gassy," and as a safety measure, boreholes were drilled into the seams from the surface, and the methane allowed to vent before mining.
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Hilt's Law states that the deeper the coal seam, the higher its rank. At deeper depths, the material encounters greater temperatures and pressure, and more plant debris is transformed into carbon. ... the Surface Mining Control and Reclamation Act of 1977 regulates the process of coal mining, and is an effort to limit the harmful effects on the ...
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Gas emission source of an excavating roadway Gas sorption and release in coal seam reservoirs. Coalnatural gas system is described by sorption and release in coal seam reservoirs. Coalbed gas is deposited in coal in two forms: one is gas adsorbed in micropores, coal molecular structure and on larger pore surface; the other is free gas in mesopores and macropores (Ceglarska ...
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In addition, mining disturbance and gas drainage will break the gasair balance in the coal seam, resulting in gasair migration driven by the pressure difference (Liu et al., 2020a, Liu et al., 2020b). Gasair migration in coal seams is shown in Fig. 1(a) and (c).
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Each link of the coal mining process will produce corresponding carbon emissions, so the carbon emissions of each link should be measured comprehensively. ... Xiaocun C, Hui T (2018) Technical scheme and application of pressurerelief gas extraction in multicoal seam mining region. Int J Min Sci Technol 28(3):483489. Article Google Scholar
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, Kexiang Li, Hongyu Ma, Jianzhong Guo, Hongming Yan, Zibing Liu, and Zhuwen Sheng Cite this: ACS Omega 2023, XXXX, XXX, XXXXXX Publication Date: September 18, 2023 https://// Copyright © 2022 The Authors. Published by American Chemical Society. This publication is licensed under CCBYNCND . Article Views
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The coal seam tested is the No. 7 coal seam that is mainly mined at this particular location. The No. 7 seam has a maximum gas pressure of MPa, an average gas pressure of MPa, and a maximum initial speed of gas release ΔP of mmHg. In addition, its highest gas content is m 3 /tr, and the minimum solidity coefficient is
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The coal seam to be mined is the #2 coal seam with a buried depth of 433708 m.
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1. Introduction. As the companion of coal seam, coal mine gas (CMG) is a major hazard source to coal mining practice. During the mining process, gas disasters such as gas explosion, gas combustion, and coal and gas outburst may occur, resulting in serious casualties and property losses. 1, 2 Especially when it enters deep mining, stress and gas pressure rise markedly, while permeability of the ...
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1. Introduction. Coal mine gas disaster is always the most dangerous in the process of coal mining [1].The determination of coal seam gas content is one of the fundamental key works involving the regional prediction of coal and gas outburst, validity check of outburst prevention, prediction of coal mine gas emission and designing gas drainage systems [2], [3].
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At present, the first coal seam in the western mining area has been exhausted, and the mine is gradually mining the lower coal seam 9. During the mining process of shallowburied and close ...
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The coal seams 7 # and 8 # in the Huaibei mining area, Anhui province, are outburst tendency. The 7 # coal seam was mined as the upper PCS to prevent coal and gas outbursts in the 8 # coal seam ...
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The comining of coal and gas is the inevitable future direction of the mining of coal resources. Taking coal mining and gas extraction as the two subsystems of the coal and gas comining system, to reveal the mechanism of action between coal mining and gas extraction is the premise of orderly comining.
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Coal seam gas and the gas crisis Residents of northwestern NSW have been watching the Pilliga project for 10 years. It was previously owned by Eastern Star Gas, chaired by the former National ...
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The occurrence and mining conditions of underground coal seams become more complex with increasing mining depth, making mining gas extraction more and more problematic (Chen et al. 2020; Wang et al. 2021a, b).Gas extraction efficiency directly depends on the coal seam permeability, which, in turn, is controlled by several internal factors (such as coal strength, stress loadingunloading ...
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Gas migration in mining disturbed coal seam (Liu et al., 2020). ... However, most current studies regard the diffusion process of gas in coal as a steadystate process, without considering time dependence of the diffusion process, resulting in a significant deviation between the model prediction results and the real experimental results. ...
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Coalbed methane (CBM), is also known as coalbed gas and coal seam gas/methane (CSG/CSM), which are terms referring to the unconventional natural gas resource stored in coal beds and are expected to be an important energy resource of global significance in the future (Rightmire 1984; Rice 1993; Flores 1998, 2013; Palmer 2010; Yang and Liu 2021). ...
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The coal seam lies at 12,316 working face, the mining gas content is about 4~6 m 3 /t, and absolute gas gush from the mine is 12~15 m 3 /min, which is a typical highstrength mining coal seam with low gas emission. As the depth and intensity of mining increases, conventional gas extraction can no longer meet requirements of safe operation.
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From this, the primary equipment and key production technologies were determined for the proposed softrock protective seam mining. Finally, in combination with the optimal arrangement of the working face, the pressurerelief gas extraction technology accomplished the pressurerelief mining of the protected coal seam. 2.
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Reservoir properties governing the emission of methane from coal seams can be divided into two groups: (1) properties that determine the capacity of the seam for total gas production,, adsorbed gas and porosity, and (2) properties that determine the rate of gas flow,, permeability, reservoir pressure, and diffusivity of coal.
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The gas migration provides a "material basis" for the gas extraction from the fractured zone of the goaf. The pressurerelief gas from the layer adjacent to the coal seam, as well as the residual gas from the mining process, flow through fracture channels and accumulate in the goaf, creating an area of gas enrichment.
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National Partnership Agreement on Coal Seam Gas and Large Coal Mining Development (2012) Australian Government, Department of Agriculture, Water and the Environment. ... Matthai SK, Rathnaweera T, Zhang G (2019) Effect of coal maturity on CO 2based hydraulic fracturing process in coal seam gas reservoirs. Fuel 236:179189. Article Google ...
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Coal and gas outbursts are a potentially fatal hazard that must be managed when mining gassy coal seams. Mininginduced stress plays an important role in outbursts, while elastic potential is accumulated to provide energy for an outburst. In this study, a largescale true triaxial (LSTT) apparatus was developed to conduct experiments and to understand the outburst mechanism and mininginduced ...
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Coal seam water injection is vital in mitigating dust pollution in coal mining operations. To investigate water imbibition and adsorption behavior on the coal surface following injection into coal seams, as well as the impact of surfactants, coal particles with sizes of 68 mm, 35 mm, and mm were selected from the Dongtan Coal Mine in Shandong Province, China.
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The gas in a coal seam is a clean energy source, but it is also the main cause of gas accidents during the mining of mineral resources. There is a large pressurerelief gas influx in the upper and lower adjacent layers of 1211 working face in the Wanfeng Coal Mine in Jinhui, Shanxi Province, China. Based on the evolution law of overburden fractures, the collaborative pressurerelief gas ...
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A Wyoming coal mine that supplies fuel to a power plant that will be converted to burn gas instead of coal will lay off 19 workers ... West ia added 1,500 coal mining jobs in 2022 and ...
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1 Introduction. Recovery of coalbed methane (CBM) from coal seams can not only benefit mining safety, reduce greenhouse gas emissions, and also increase clean energy supply (Karacan et al., 2011; Moore, 2012).In the Junggar Basin, the CBM resources have been estimated at trillion cubic meters, which is the third largest CBM basin in China after the Qinshui Basin and Ordos Basin (Fu et al ...
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As the coal mining depth increases, the coal seam gas pressure and gas content increase, mining conditions become more complicated, and the coal seam permeability decreases. Therefore, only relying on the primary pore and fissure structure of coal reservoirs for free extraction is not conducive to the sustainable development of the energy ...
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Coal seam gas formation. During coalification, large quantities of methane are generated. This gas is adsorbed onto the coal surface in cleats and pores, and is held in place by reservoir and water pressure. Coal rank, reservoir pressure (related in part to depth) and temperature are important factors controlling the amount of methane held in a ...
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