Controlling factors of symbiotic disaster between coal gas and spontaneous combustion in longwall mining gobs

Xia, Tongqiang; Zhou, Fang; Wang, Xinxin; Zhang, Yifan; Li, Yimin; Kang, Jianhong; Liu, Jishan

doi:10.1016/j.fuel.2016.05.090

Cited by 161 publications

(72 citation statements)

References 22 publications

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“…Comparing Figures 7 and 8, it is found that the oxygen concentration on the air intake side of the same location is generally higher than that on the air return side. Due to the combination of air seepage and oxygen dispersion, oxygen concentration nearby the air intake side of gob is high, which is consistent with the results of the literature [13,24,25,30,31].…”

Section: Oxygen Concentration Distribution In Gobsupporting

confidence: 92%

Oxygen Distribution and Air Leakage Law in Gob of Working Face of U+L Ventilation System

Zhai

Wang

Jiang

et al. 2019

Mathematical Problems in Engineering

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In order to prevent and control coal spontaneous combustion effectively in the gob of U+L working face, the 30105 working face of Hanglaiwan mine was taken as the research object. The relationship models between oxygen concentration and burial depth of the two tunnels in the gob of U+L working face were established. The distribution of oxygen in the gob of the working face of U+L ventilation system was studied by field observation combined with numerical simulation. The results show that the air leakage in the gob is serious. There are a number of fluctuation areas where the oxygen concentration first decreases and then increases in the air intake side of the gob. The oxygen concentration peaked at 100m, 175m, and 245m, respectively, from the intake side of the gob. In the same position of the gob depth, the air leakage intensity on the intake side is generally higher than that on the return side, and the oxygen concentration on the intake side of the gob is slower than the return side. Oxygen concentration maintains at 5.09% when the depth of gob reaches 400m. Measures to prevent coal spontaneous combustion should be strengthened in the air intake side.

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Section: Oxygen Concentration Distribution In Gobsupporting

confidence: 92%

Oxygen Distribution and Air Leakage Law in Gob of Working Face of U+L Ventilation System

Zhai

Wang

Jiang

et al. 2019

Mathematical Problems in Engineering

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“…With advanced mining equipment and technologies, longwall mining of coal seams [1][2][3][4] and in situ leaching of uranium [5][6][7] have been widely accepted. However, as a stack resource, the efficiency and safety of coal and uranium mining are important for energy demand, economic development, and ecological balance.…”

Section: Introductionmentioning

confidence: 99%

Coupled Multifield Response to Coordinate Mining of Coal and Uranium: A Case Study

Zhang

Yuan

Wei

et al. 2020

Water

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The coordinate mining of stack resources in the Ordos Basin, which involves the coupling effects of stress fracture, seepage, and reactive solute transport, plays an important role in resource exploration and environment protection. A coupled multiphysical–chemical model, involving a modified non-Darcy flow model, a leaching solution reaction, and a reactive solute transport model, was developed in this study. The Fast Lagrangian Analysis of Continua -Computational Fluid Dynamics (FLAC3D-CFD) simulator coupled with the developed models was used to investigate the evolution and morphology of mining-induced multifield coupling for the scenarios of concurrent mining and asynchronous mining of coal and uranium. As mining advanced to 160 m, the maximum principle stress characterized by a stress shell was observed. As mining progressed to 280 m, a rupture occurred, and a new stress shell was generated as a rear skewback was formed by the concentrated stress of the stope. An “arch-shaped” fracture field combined with a “saddle-shaped” seepage field was identified in the destressed zone of the stress shell. In the coordinated mining of uranium prior to coal, “funnel-shaped” and “asymmetric saddle-shaped” morphologies of the leaching solution were found during coal mining for ventilation in the stope and mining face. By contrast, “saddle-shaped”, “inclined funnel-shaped”, and “horizontal” morphologies of the leaching solution were observed for a short period for ventilation of the stope and mining face for coal mining prior to uranium mining, uranium mining prior to coal mining, and synchronized coal and uranium mining. A dynamic stress response was obtained in the coal seam, followed by the conglomerate aquifer and the uranium deposits. The diffusion depth of the solution was negatively correlated with the injection velocity and the pumping ratio and positively correlated with the diffusion coefficient. A dynamic increase in diffusion depth was observed as the diffusion coefficient increased to 1 × 10−4 m2/s.

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“…China is one of the most severely threatened nations in terms of the risks of coal and gas outburst in underground coal mines. In recent decades, as coal mining depths have increased, the majority of low-gassy coal mines have become high-gassy and outburst-prone mines that reduce the safety and advantage of mining [1]. Coal mine methane (CMM) extraction is the most fundamental approach to eliminate the risk of coal and gas outburst.…”

Section: Introductionmentioning

confidence: 99%

Fully Coupled Multi-Scale Model for Gas Extraction from Coal Seam Stimulated by Directional Hydraulic Fracturing

Zhang

Sun

et al. 2019

Applied Sciences

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Although numerous studies have tried to explain the mechanism of directional hydraulic fracturing in a coal seam, few of them have been conducted on gas migration stimulated by directional hydraulic fracturing during coal mine methane extraction. In this study, a fully coupled multi-scale model to stimulate gas extraction from a coal seam stimulated by directional hydraulic fracturing was developed and calculated by a finite element approach. The model considers gas flow and heat transfer within the hydraulic fractures, the coal matrix, and cleat system, and it accounts for coal deformation. The model was verified using gas amount data from the NO.8 coal seam at Fengchun mine, Chongqing, Southwest China. Model simulation results show that slots and hydraulic fracture can expand the area of gas pressure drop and decrease the time needed to complete the extraction. The evolution of hydraulic fracture apertures and permeability in coal seams is greatly influenced by the effective stress and coal matrix deformation. A series of sensitivity analyses were performed to investigate the impacts of key factors on gas extraction time of completion. The study shows that hydraulic fracture aperture and the cleat permeability of coal seams play crucial roles in gas extraction from a coal seam stimulated by directional hydraulic fracturing. In addition, the reasonable arrangement of directional boreholes could improve the gas extraction efficiency. A large coal seam dip angle and high temperature help to enhance coal mine methane extraction from the coal seam.

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Controlling factors of symbiotic disaster between coal gas and spontaneous combustion in longwall mining gobs

Cited by 161 publications

References 22 publications

Oxygen Distribution and Air Leakage Law in Gob of Working Face of U+L Ventilation System

Oxygen Distribution and Air Leakage Law in Gob of Working Face of U+L Ventilation System

Coupled Multifield Response to Coordinate Mining of Coal and Uranium: A Case Study

Fully Coupled Multi-Scale Model for Gas Extraction from Coal Seam Stimulated by Directional Hydraulic Fracturing

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