Gas Concentration Distribution Law in the Roadway after Coal and Gas Outburst

Gas emission happens after coal and gas outburst, and it could cause secondary disasters in the roadway. Therefore it is necessary to research gas concentration distribution law in the roadway after coal and gas outburst, and theoretical basis for avoiding the occurrence of secondary disasters could be provided. Based on the above, Fluent is used to simulate gas concentration distribution law in the roadway during outburst. The research results show that gas velocity of the initial stage is larger in the whole process of gas outburst and gas emission impacts opposite walls in the form of jet in the roadway intersection. The flow changes direction and moves along the main airway and return airway. It produces countercurrent along the main airway. Because the pressure in the main airway is high, gas migration velocity becomes zero after a certain distance and is "back" to return airway. The higher the outburst velocity is, the longer the flow length is. Gas concentration variation with two kinds of different outburst intensities and position are regressed and it shows that correlation coefficients of power function are the highest. The research results have a certain theoretical value to prevent the occurrence of secondary disasters after coal and gas outburst.

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Study on Rock Burst Early Warning in the Working Face of Deep Coal Mines Based on the Law of Gas Emission

Advances in Civil Engineering ◽

10.1155/2021/9940505 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Qinghua Zhang ◽

Shudong He

Keyword(s):

Rock Burst ◽

Early Warning ◽

Critical Value ◽

Gas Emission ◽

Distribution Law ◽

Deep Mine ◽

Gas Concentration ◽

Research Results ◽

Working Face ◽

The Law

This study is aimed at predicting rock burst disasters in high gas mines. First, the distribution law and correlation of gas and stress in the F15-17-11111 working face of Pingdingshan No. 13 Mine were analyzed based on the coupling relationship between gas emission and stress in the working face. Next, the relationship between gas emission and stress distribution was revealed, and an early warning method of rock burst in the deep mine working face based on the law of gas emission was proposed and applied to the F15-17-11111 working face. Finally, the critical value of the gas concentration indicator for rock burst early warning in the F15-17-11111 working face was determined as 0.05%. The following research results were obtained. The gas emission and the mining stress in the F15-17-11111 working face are negatively correlated. Mechanically, their correlation satisfies the typical coupling. Besides, the critical value of the gas concentration indicator determined by the proposed early warning method boasts high accuracy in predicting rock burst disasters. It can be used as an early warning method for underground rock burst disasters to promote the safety of working face mining. The research results provide reference and guidance for the monitoring and early warning of rock burst disasters in deep high gas mines.

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Deformation Analysis for Coal and Gas Outburst Cavity

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.2607 ◽

2011 ◽

Vol 121-126 ◽

pp. 2607-2613

Author(s):

Qian Ting Hu ◽

Wen Bin Wu ◽

Guo Qiang Cheng

Keyword(s):

Damage Zone ◽

Coal And Gas Outburst ◽

Gas Content ◽

Combination Method ◽

Deformation Analysis ◽

Failure Zone ◽

Finite Element Code ◽

Cavity Volume ◽

Gas Emission ◽

Gas Outburst

Outburst cavity formed during coal and gas outburst can be pear shaped, elliptical, or just like an irregularly elongated ellipsoid, its capacity is always smaller than the volume of ejected coal. And the gas emission quantity is almost 4 to 10 times as gas content in ejected coal. These are two different expressions of the same problem. To find the reasons for the decrease of outburst cavity volume and the increase of gas emission quantity per ton, by using the finite element code ANSYS, the damage zone and the failure zone of the outburst cavity were determined based on the static and dynamic combination method. In this paper, the reason for the decrease of the outburst volume was explained.

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Analysis of the Occurrence Mechanism for Coal and Gas Outburst Based on Multiple Discriminant Indices

Shock and Vibration ◽

10.1155/2019/7572910 ◽

2019 ◽

Vol 2019 ◽

pp. 1-17 ◽

Cited By ~ 1

Author(s):

Hai Rong ◽

Hongwei Zhang ◽

Bing Liang ◽

Weihua Song

Keyword(s):

Coal Mine ◽

Regional Distribution ◽

Geological Structure ◽

Coal And Gas Outburst ◽

Prevention Measures ◽

Distribution Law ◽

Risk Levels ◽

Gas Outburst ◽

Prediction And Prevention ◽

Occurrence Mechanism

In order to reveal the occurrence mechanism of coal and gas outburst and optimize the measures to prevent the disaster, a coal mine in Henan Province was undertaken as the research background. Based on the geological and mining conditions of the coal mine, the gas geological analysis method is applied to determine the outburst occurrence and to classify the risk levels. A multifactor pattern recognition method is used to determine the risk probability of the dynamic disasters such as coal and gas outburst. The relationship between geological structure, rock mass stress, and mine dynamic hazards is determined using geo-dynamic division method and FLAC3D numerical simulation. The occurrence and manifestation characteristics of the dynamic hazards are determined. COMSOL Multiphysics software is used to evaluate the original prevention measures and to optimize the measures. The research results determine the main influencing factors and regional distribution law of coal and gas outburst, which is of great significance to the risk prediction and prevention of dynamic disasters such as coal and gas outburst.

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Features of Jianshanchong Klippe and its Control to Gas Geology at Qingshan Coal Mine, Jiangxi Province

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.164.501 ◽

2012 ◽

Vol 164 ◽

pp. 501-505

Author(s):

Zhi Gen Zhao ◽

Jia Chen ◽

Jia Ping Yan

Keyword(s):

Coal Seam ◽

Coal Mine ◽

Emission Rate ◽

Coal And Gas Outburst ◽

Jiangxi Province ◽

Coal Seams ◽

Gas Emission ◽

Gas Outburst ◽

Transverse Profile ◽

Tectonic Coal

The coal and gas outburst is serious at Qingshan Coal Mine of Jiangxi Province, so it is of significance to research the features of Jianshanchong klippe and its control to gas geology. The research reveals that: Jianshanchong klippe is distributed from the east boundary of Qingshan Coal Mine to No. 45 Exploration Line, its transverse profile is like a funnel while its longitudinal profile is like a wedge, northwest side of the klippe is thicker and deeper while southeast side is thinner and more shallow. Because of the cover and insert of Jianshanchong klippe, the structure of coal-bearing strata is more complex, some secondary folds are formed, and also, the coal seam is changed greatly, the tectonic coal is well developed and the coal seam is suddenly thickening or thinning. Due to the effect of Jianshanchong klippe, the coal and gas outbursts occur in the area of secondary folds, thicker coal seams or tectonic coals. Concerning the prediction of gas geology in deep area, in view of the facts including simpler structure, stable coal seam and decreased thickness, the gas emission rate and the coal and gas outburst will decrease in Fifth and Sixth Mining Level than that in Second and Third Mining Level

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Characters of Electromagnetic Radiation in Coal and its Application in Forecast of Coal and Gas Outburst

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.962-965.1051 ◽

2014 ◽

Vol 962-965 ◽

pp. 1051-1055 ◽

Cited By ~ 2

Author(s):

Wen Cai Wang ◽

Hui Zhao ◽

Hong Yu Zhao ◽

Qing Tian Zhang

Keyword(s):

Electromagnetic Radiation ◽

Radiation Intensity ◽

Correlation Equation ◽

Coal And Gas Outburst ◽

Initial Speed ◽

Gas Emission ◽

Radiation Characteristics ◽

Positive Correlation ◽

Loading Process ◽

Gas Outburst

The coal can produce electromagnetic radiation when it is in the loading process. The electromagnetic radiation characteristics testing to the sample in the process of uniaxial compression failure in the lab shows that loading stress and the strength of electromagnetic radiation, the number of electromagnetic radiation pulse, the number of acoustic emission pulse are positively correlated relationship when it is in the loading process. They usually have a good corresponding relationship with each other, but are not completely synchronization. They test the corresponding relationship between the electromagnetic radiation intensity of coal and main parameters gas emission initial speed of traditional prediction of coal and gas outburst borehole and amount of drilling cuttings. The results show that the electromagnetic radiation intensity and gas emission initial speed of borehole and amount of drilling cuttings have a positive correlation, and the linear positive correlation equation is obtained. Thus it can be seen, electromagnetic radiation characteristics can be used for predicting the outburst of coal and gas.

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Disastrous Mechanism and Concentration Distribution of Gas Migration in Fully Mechanized Caving Stope in Wuyang Coal Mine

Geofluids ◽

10.1155/2021/4366942 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Li Chong ◽

He Sifeng ◽

Xu Zhijun

Keyword(s):

Coal Mine ◽

Concentration Distribution ◽

Spontaneous Combustion ◽

Concentration Field ◽

Gas Migration ◽

Coal Spontaneous Combustion ◽

Gas Drainage ◽

Gas Concentration ◽

Research Results ◽

Working Face

The overrunning disaster of harmful gas tends to occur in the working face in thick coal seam with high gas concentration, as the fully mechanized caving stope has the characteristics of high mining intensity, high remnant coal, and high gas content. Therefore, the disastrous mechanism and concentration distribution of gas migration in fully mechanized caving stope are the theoretical basis for gas control scheme. Based on the 7607 working face in Wuyang coal mine, the gas emission quantity in working face is comprehensively analyzed by field measurement in this paper. The gas leakage field, oxygen concentration field, and gas concentration field in 7607 working face are simulated by establishing the equal proportional numerical model. Due to the increase of air leakage in working face caused by the high alley pumping drainage, the risk of coal spontaneous combustion is also analyzed, when gas extraction in goaf is carried out. The research results show that the gas drainage technology in high drainage roadway has a remarkable effect on the gas overrunning phenomenon. The gas concentration near the upper corner of the working surface has been reduced from 0.7%-1% to 0.5%. At the same time, it is necessary to pay attention to the risk of coal spontaneous combustion in the goaf for gas drainage in the high drainage roadway. The width of the oxidation zone in the goaf is about 25 m deeper than that before the drainage. Research results provide the references for gas control technology and coal spontaneous combustion prevention in similar working faces.

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Early warning of coal and gas outburst based on abnormal gas emission

E3S Web of Conferences ◽

10.1051/e3sconf/202125703067 ◽

2021 ◽

Vol 257 ◽

pp. 03067

Author(s):

Ming Deng

Keyword(s):

Early Warning ◽

Time Series Data ◽

Coal And Gas Outburst ◽

Series Data ◽

Horizontal Line ◽

Information Function ◽

Gas Emission ◽

Single Time ◽

Gas Outburst ◽

Line Diagram

Taking the dynamic time series data of gas emission in mining face as the research object, the early warning model of coal and gas outburst was established based on single-time gas emission information function. Based on the data of 21118 heading face before outburst of Panyi Mine in Huainan, the single-time gas emission information function diagram was drawn, named as G-line diagram in short. The result showed that during normal production period, the entity of G-line diagram was small, which was close to a stable horizontal line. And before the outburst, the G-line diagram showed an upward trend. The negative and positive entity of G-line diagram became larger. At the same time, there were many times positive lines in the process of rising. According to the different shape, colour, length and other characteristics of G-line diagram, the change trend of coal body state in front of working face can be judged. Based on that, the outburst symptoms in the incubation stage of coal and gas outburst can be identified, and the early warning of outburst can be realized. It is of great significance to ensure the safety of mine production.

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The Airflow Reversal Law in Ventilation System after Coal and Gas Outburst in Tunneling Roadway

Shock and Vibration ◽

10.1155/2021/7975005 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Junhong Si ◽

Yiqiao Wang ◽

Genyin Cheng ◽

Lin Li ◽

Yitian Shao ◽

...

Keyword(s):

Ventilation System ◽

Simulation Method ◽

Coal And Gas Outburst ◽

Air Velocity ◽

Relative Variation ◽

Gas Concentration ◽

Gas Outburst ◽

Cubic Polynomial ◽

The Relationship ◽

Topology Graph

Considering the coal and gas outburst phenomenon in the mining space, this paper analyzes the main characteristics of coal and gas outburst accidents, defines the outburst airflow reversal degree, and constructs a simplified topology graph of tunneling ventilation system, while the air door is not destroyed. Using the numerical simulation method, this paper elaborates on the relationship between the outburst pressure and airflow reversal degree. The results indicate that the inlet pressure increases to 264 hPa and the outlet pressure increases to 289 hPa when the outburst pressure increases from 1 hPa to 1 MPa, and the relative variation coefficient of pressure decreases from 1501.5 to 1.62 in the inlet of return airway and decreases from 2002 to 1.65 in the outlet of return airway. Furthermore, the air velocity decreases from −1.38 to −284.44 m/s in the inlet and increases from 3.10 to 297.38 m/s in the outlet. Moreover, the gas concentration of the inlet and outlet in return airway increases rapidly with the increase of outburst pressure. When the outburst pressure is greater than 0.15 MPa, the gas concentration will be over 98% in tunneling ventilation system. This paper also finds out a cubic polynomial relationship existing between the reversal degree and the outburst pressure. It provides the prediction of coal and gas outburst and serves as a guidance in case mine ventilation disturbances occur.

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Research on Rapid Excavation Technology of Roadway in Coal Seam with the Risk of Coal and Gas Outburst

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.325 ◽

2012 ◽

Vol 524-527 ◽

pp. 325-329 ◽

Cited By ~ 2

Author(s):

Shou Tao Hu ◽

Bai Sheng Nie ◽

Ming Ju Liu ◽

Yan Wei Liu ◽

Xiang Chun Li ◽

...

Keyword(s):

Coal Seam ◽

Rail Transport ◽

Coal And Gas Outburst ◽

Gas Content ◽

Gas Emission ◽

Gas Outburst ◽

Drilling Hole ◽

Rapid Excavation ◽

Standard Gas

According to the questions of long eliminating coal and gas outburst period, large projects and slow driving came from the regional measurement of drilling hole ,the paper select 2371 (1) rail transport roadway as experiment for using along seam long drilling as a regional measurement to eliminate coal and gas outburst. Since the regional measurement of along seam long drilling had been carried out, the remaining gas content decreased more than 60％, max Smax was 5.4kg/m, max qmax was 2.01/min.Both Smax and qmax were not beyond the standard. Gas concentrations were not overrun. Gas emission decreased in the roadway afterward. The regional measurement eliminated the risk of coal and gas outburst in effect. Heading face promoted 423m forward safely. The max January footage could reach 120m.Achieve driving of heading face safely and fast.

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