Study on the air leakage characteristics of a goaf in a shallow coal seam and spontaneous combustion prevention and control strategies for residual coal

Li, Jianwei; Li, Xintian; Zhang, Ningbo

doi:10.1371/journal.pone.0269822

Cited by 12 publications

(5 citation statements)

References 30 publications

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“…A vertical stress of 2 MPa was applied above the model, and the lateral pressure coefficient was 1.0. Fixed displacements were applied to the front, rear, left, right, and bottom of the model to define the boundary, and the Mohr-Coulomb constitutive relation was used as the model operation criterion (Gao, 2019;Yang et al, 2019;Xue et al, 2020;Yu et al, 2020;Zhou et al, 2020;Li et al, 2022). The three-dimensional numerical model is shown in Figure 5, and the rock mechanical parameters are shown in Table 1.…”

Section: Stress Distribution Of the Coal Pillar Above The Panelmentioning

confidence: 99%

Research on behavior of underground pressure in shallow coal seam with three-face goaf working face

et al. 2022

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During the mining process of coal mines, coal pillars are often formed in the goaf on three sides, and the stress behavior of coal seams has a significant impact on the safety of coal mines. The upper part of panel 3104 of Xinwang Coal Mine is the room-pillar goaf of the 2# coal seam, and the lower part is the goaf of the 7# coal seam. The same coal seam is adjacent to the goaf of panel 3102. Therefore, there are hidden dangers for safe mining in panel 3104 affected by the goaf on three sides. Through FLAC3D numerical simulation, on-site Pasat-M detection, microseismic monitoring, and support resistance measurement, the stress distribution law of surrounding rock in the working face is analyzed. The following conclusions are obtained. There are several high wave velocity stress concentration areas in the coal body of 3104 working face. During the mining of the working face, the mining influence 90m in front of the working face began to spread to the area of the left coal pillar, and the vertical stress at the left coal pillar began to increase. Stress concentration appears in 0–20m strata at the top of 3# coal seams. At the top of a 3# coal seam, the vertical stress concentration coefficient can reach 2 in the range of 4–12m. The influence range of 3104 working face mining advance can reach 200m. Under the influence of mining, a large number of microseismic events occurred at 160m above and 150m below 3# coal seam. This law has reference value for the mining strata behaviors of coal seams under similar conditions.

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Section: Stress Distribution Of the Coal Pillar Above The Panelmentioning

confidence: 99%

Research on behavior of underground pressure in shallow coal seam with three-face goaf working face

et al. 2022

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“…Delving into the generation law of flue gas during coal spontaneous combustion and its consequential impact on methane explosion limits not only enriches our comprehension of the perils posed by methane explosion disasters stemming from coal spontaneous combustion in goaf but also fortifies our arsenal of preventive and mitigation measures against such calamitous events [14,15]. Hence, a plethora of scholarly endeavors have been dedicated to scrutinizing the methane explosion risk under the aegis of CSC conditions [16]. The genesis of combustible gases poses a palpable escalation in the risk profile of methane explosions [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Investigating the Influence of Flue Gas Induced by Coal Spontaneous Combustion on Methane Explosion Risk

Hu,

Li,

Zhu

et al. 2024

Fire

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During the process of coal spontaneous combustion (CSC), a plethora of combustible gases alongside inert gases, such as CO2, are copiously generated. However, prior investigations have regrettably overlooked the pivotal influence of inert gas production on the propensity for methane explosions during CSC. To investigate the impact of the flue gas environment generated by CSC, containing both combustible and inert gases, on the risk of methane explosion, a high-temperature programmed heating test system for CSC was employed to analyze the generation pattern of flue gas. It was found that CO, CO2, and CH4 were continuously generated in large quantities during the process of CSC, which are the main components of CSC flue gas. The effect of the concentration and component ratio (CCO2/CCO) of the flue gas on the methane explosion limit was tested. It was found that the CSC flue gas led to a decrease in the methane explosion limit, and that the explosion limit range was facilitated at 0 < CCO2/CCO < 0.543 and suppressed at CCO2/CCO > 0.543. As the temperature of CSC increases, the risk of methane explosion is initially suppressed. When the coal temperature exceeds 330~410 °C, the explosion risk rapidly expands.

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“…GERRC is regarded as the third technological revolution in longwall mining in China. − By breaking the pressure transmission of the roof through directional pre-splitting and roof cutting, automatic roadway formation and coal pillar-free mining are achieved, aided by the mine pressure. − This phenomenon changes gas migration, causing fresh air to leak continuously into the gob from the working face. − The increased likelihood of spontaneous combustion in residual coal − not only decreases the economic viability of coal mining but also poses significant threats to the safety of underground workers. − Many scholars have conducted extensive research in this area. Wang et al analyzed and calculated the expansion coefficient of collapsed gangue over time and space, and they examined the effect of roof movement on the flow field in a mining scenario where the gangue is retained in the entryway via a cutting method.…”

Section: Introductionmentioning

confidence: 99%

“… 8 − 10 The increased likelihood of spontaneous combustion in residual coal 11 − 14 not only decreases the economic viability of coal mining but also poses significant threats to the safety of underground workers. 15 − 17 Many scholars have conducted extensive research in this area. Wang et al 18 analyzed and calculated the expansion coefficient of collapsed gangue over time and space, and they examined the effect of roof movement on the flow field in a mining scenario where the gangue is retained in the entryway via a cutting method.…”

Section: Introductionmentioning

confidence: 99%

Study on Nitrogen Injection Fire Prevention and Extinguishing Technology in Spontaneous Combustion Gob Based on Gob-Side Entry Retaining

Zhou

Jing

et al. 2023

ACS Omega

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Under the gob-side entry retaining mining mode with roof cutting and pressure relief (GERRC), the gob and retained roadway section are interconnected to create an open area. Owing to the increased airflow, the coal remnants in the gob are more prone to spontaneous combustion. This study aimed to investigate the distribution of oxygen concentration within a gob and identify optimal parameters for nitrogen injection. The engineering context was the "110 method" introduced in the 1201 working face of the South Five mining area at Daxing. Computational fluid dynamics simulation software was used to analyze the effects of various nitrogen injection treatment parameters on the overall performance of the gob, including their impact on oxygen distribution. The simulation results showed that air leakage within the gob primarily originates from the working face adjacent to the intake roadway, as well as gaps within the retained roadway. The increased air leakage causes the high O 2 concentration range in the gob to expand, and the retained roadway section is connected to an area with a high concentration of oxygen near the working face, which increases the risk of residual coal spontaneous combustion. The results show that the optimal nitrogen injection conditions for inerting and reducing the risk of spontaneous combustion within the gob require an injection quantity of 500 m 3 /h, with the injection point located at a depth of 60 m. With these parameters, the range of the oxidation zone was significantly reduced. To monitor the O 2 concentration and temperature change curves in the gob during the project implementation, a bundle tube monitoring system was used, considering the actual mining situation. By varying the nitrogen injection spacing and quantity, we found that injecting nitrogen at a spacing of 30 m and at a quantity of 500 m 3 /h effectively placed most areas of the gob in the suffocation zone, reducing the risk of spontaneous combustion of residual coal. The accuracy of the simulation was verified. The study offers valuable insights into improving safety in coal mines and reducing spontaneous combustion incidents, providing important reference significance for fire prevention and control.

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Study on the air leakage characteristics of a goaf in a shallow coal seam and spontaneous combustion prevention and control strategies for residual coal

Cited by 12 publications

References 30 publications

Research on behavior of underground pressure in shallow coal seam with three-face goaf working face

Research on behavior of underground pressure in shallow coal seam with three-face goaf working face

Investigating the Influence of Flue Gas Induced by Coal Spontaneous Combustion on Methane Explosion Risk

Study on Nitrogen Injection Fire Prevention and Extinguishing Technology in Spontaneous Combustion Gob Based on Gob-Side Entry Retaining

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