Investigation of Spontaneous Combustion Zones and Index Gas Prediction System in Goaf of “Isolated Island” Working Face

Chai, Jiamei

doi:10.3390/fire5030067

Cited by 8 publications

(3 citation statements)

References 27 publications

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“…Affected by factors such as mining, crustal stress, and CSC, the coal rock in goaf undergoes compression deformation and fracture, forming a caving zone, fracture zones, and curved subsidence zones in the vertical direction of the goaf [28,29]. The irregular arrangement of collapsed coal rocks and residual coal in the caving zone creates a specific void space under the influence of geology, mining, and coal rock properties.…”

Section: Permeability Evolution Of Goafmentioning

confidence: 99%

Study on the Effect of Pore Evolution on the Coal Spontaneous Combustion Characteristics in Goaf

Li,

Xu,

2024

Fire

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Understanding the characteristics of coal spontaneous combustion (CSC) in goaf under different porosities is crucial for comprehending the mechanism of CSC and its prevention and control. In this paper, a multi-field coupled model of CSC in the goaf, considering porosity variation, is developed to investigate the effect of porosity on the CSC characteristics in the goaf. The results indicate that, as the goaf depth increases, both porosity and permeability decrease. When the highest goaf porosity is 25%, the average airflow velocity is between 0.00134 and 0.00139 m/s. In contrast, the average airflow velocity in the goaf with a porosity of 40% is approximately six times greater than that of the goaf with a porosity of 25%. As the goaf porosity increases, the overall oxygen concentration, temperature, and oxidized zone area also rise. Moreover, the oxidation zone area can be quantified and visualized, thereby enabling more effective prediction of the CSC risk in the goaf. The findings of the study have a positive significance in guiding the prevention and control of coal fires.

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Section: Permeability Evolution Of Goafmentioning

confidence: 99%

Study on the Effect of Pore Evolution on the Coal Spontaneous Combustion Characteristics in Goaf

Li,

Xu,

2024

Fire

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“…Sun et al used three-dimensional CT reconstruction technology to extract the pore network structure of a coal sample and found that the injectivity and permeability of the heated coal samples were poor after nitrogen injection. Chai conducted a temperature-programmed experiment on coal and improved the prediction index gas system of SC, suggesting that CO and C 2 H 4 can be used as warning indicators for suspended solids in the gob. The scope of the “three zones” of spontaneous combustion can be comprehensively determined by the oxygen concentration, air leakage velocity, and temperature in the gob. , Through the coal spontaneous combustion experiment, Gui et al developed a method to determine the “three zones” of a gob using O 2 concentration through regression analysis.…”

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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“…Zhao Shankun proposed the synergistic anti-collision mechanism of a deep-hole roof presplitting blasting stress structure by analyzing the stress field of blasted rock mass, the plastic failure zone, and the stress and displacement change rules under different blasthole arrangements [18]. Chai Jiamei aimed to resolve the problem of coal SC in the goaf of an "isolated-island" fully mechanized caving face; a multiphysics model coupled with a gas flow field and a gas concentration field was established in the present study, and an accurate division of spontaneous combustion (SC) zones in the goaf and the determination of the prediction system of the SC index are developed [19]. lgor lvanovich Bosikov developed a generalized expression for the transfer functions of coalmine objects, taking into account delays, and carried out the method for managing the process of changing connections between devices (controllers-switches) of the technical system [20].…”

Section: Introductionmentioning

confidence: 99%

Study on the Energy Release Law of Overburden Rock Breaking and Anti-Rockburst Technology in the Knife Handle Working Face of a Gently Inclined Coal Seam

Cui,

Sun,

Lai

et al. 2023

Applied Sciences

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This study aims at the problems of the difficulty in controlling the stability of the surrounding rock and the high-impact danger of knife handle-type working face mining. We take the I010206 working face of Kuangou Coal Mine in Xinjiang as the engineering background, establish the mechanical model of roof periodic fracture and the FLAC3D numerical model of a working face, and analyze the evolution characteristics of the surrounding rock stress and energy when the working face is widened, revealing the mechanism of induced impact caused by overburden fracture in the working face, putting forward the technology of hydraulic fracturing to relieve the danger in the roof area, and comparing the pressure relief effect. The research results show the following: (1) After the working face is widened, the overlying strata load is transferred to the coal seam in front of the working face and the upper and lower sides of the working face. after mining; the abutment pressure of the I010408 working face in the B4-1 coal seam is superimposed with the abutment pressure of the I010206 working face in the B2 coal seam, the stress concentration is higher, and the lateral support pressure of the goaf forms a high static load. The large-area roof caving forms a high dynamic load. All of them are more likely to induce rockburst. (2) In knife handle-type working face mining, the peak value of the advanced abutment pressure in working faces first decreases and then increases, and the advanced abutment pressure increases from 10.31 MPa to 14.62 MPa; the peak value and concentration degree of strain energy density increase with the increase in working face width. (3) Measures were proposed to weaken the hydraulic fracturing roof in advance. After using hydraulic fracturing technology, the pressure step distance of the working surface roof was reduced, and the microseismic energy frequency was significantly reduced. These measures reduced the impact risk of the working face and ensured the safe mining of the working face.

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Investigation of Spontaneous Combustion Zones and Index Gas Prediction System in Goaf of “Isolated Island” Working Face

Cited by 8 publications

References 27 publications

Study on the Effect of Pore Evolution on the Coal Spontaneous Combustion Characteristics in Goaf

Study on the Effect of Pore Evolution on the Coal Spontaneous Combustion Characteristics in Goaf

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

Study on the Energy Release Law of Overburden Rock Breaking and Anti-Rockburst Technology in the Knife Handle Working Face of a Gently Inclined Coal Seam

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