Deformation Analysis for Coal and Gas Outburst Cavity

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.

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

2012 ◽  
Vol 524-527 ◽  
pp. 325-329 ◽  
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.

Application of Weighted Moving Average Model on the Pre-Warning of Coal and Gas Outburst

2012 ◽  
Vol 524-527 ◽  
pp. 535-538
Author(s):  
Ming Deng ◽  
De Fang Liu ◽  
Qin Hua Chen
Keyword(s):  
Moving Average ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Gas Emission ◽  
Short Term ◽  
Term Trend ◽  
Gas Outburst ◽  
Moving Average Model ◽  
Short Term Trend ◽  
Weighted Moving Average

By defining and studying the time series of gas emission concentration (which was called G series in the paper), weighted moving average (WMA) model for pre-warning of coal and gas outburst was developed. The long & short-term trend curved lines of G series were drawn with the data of “3.30” coal and gas outburst of a coal mine. The results indicate, at normal production periods, coal body containing gas kept relatively steady, the gas content curved line, and long & short-term trend curved lines all changed mildly. Before occurring of outburst, some abnormal variations were found, including roadway body broken, gas energy released obvious increase or fluctuation of gas emission concentration, the gas content curved line passing through moving average curved line, long-term and short-term trend curved lines breaking through each other. The result of this study can be selected as the precursors to pre-warning coal and gas outburst.

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

2015 ◽  
Vol 713-715 ◽  
pp. 314-318
Author(s):  
Chun Li Yang ◽  
Yi Liang Zhao ◽  
Xiang Chun Li ◽  
Yang Yang Meng ◽  
Fei Fei Zhu
Keyword(s):  
Concentration Distribution ◽  
Correlation Coefficients ◽  
Coal And Gas Outburst ◽  
Gas Emission ◽  
Distribution Law ◽  
Gas Concentration ◽  
Research Results ◽  
Gas Outburst ◽  
Whole Process ◽  
Secondary Disasters

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.

Prediction Technology of Coal and Gas Outburst in Xuandong Coal Mine

2011 ◽  
Vol 255-260 ◽  
pp. 3731-3734
Author(s):  
Sheng Shan Zhao ◽  
Wei Dong Pan ◽  
Xin Wang ◽  
Jia Dun Liu
Keyword(s):  
Coal Mine ◽  
Magmatic Rock ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Burial Depth ◽  
Disaster Reduction ◽  
Geological Structures ◽  
Practical Situation ◽  
Gas Outburst ◽  
Geological Conditions

Based on the complicated geological conditions of coal seam in Xuandong Coal Mine, such as deep burial depth, high gas content, magmatic rock intrusion and so on, the distribution regularities of magmatic rock, gas and geological structures were analyzed and studied. Combining with the practical situation of the dynamic disaster and phenomenon during the mining, the dangerous zones of coal and gas outburst were predicted and regional divided. The research results would have certain significance of practical guide to the outburst prevention and disaster reduction.

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

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

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

2014 ◽  
Vol 962-965 ◽  
pp. 1051-1055 ◽  
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.

Characteristics of Coal and Gas Outburst within Gas Geological Units in Qidong Mine

2013 ◽  
Vol 734-737 ◽  
pp. 45-51
Author(s):  
Ai He Chen ◽  
Dong Ji Lei ◽  
Yu Gui Zhang
Keyword(s):  
Magmatic Rock ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Coal Bed ◽  
Burial Depth ◽  
Gas Outburst ◽  
Prediction And Prevention ◽  
Gas Occurrence ◽  
Tectonic Coal ◽  
Geological Units

The precise mechanism of the coal and gas outburst is still unresolved, but productive practices in Qidong mine have testified that the coal and gas outburst accidents are predominantly associated with the belt of geological structure, the zone of tectonic coal occurrence and the area of the stress concentration. So it is very important to study characteristics of coal bed gas geology for coal bed gas prediction and prevention. Using gas-geology theory and method, the research focused on the factors of coal and gas outburst, such as coal bed gas occurrence, stress distribution, tectonic coal occurrence and magmatic rock presence within Qidong mine. The result shows that: Qidong mine district could be divided into 4 geological units by 3 faults as the boundary, the faults of Weimiao fault, F2, and F5; there are different conditions and main controlling factors of coal bed gas occurrence within four geological units. The unit I of geology: coal bed gas occurrence conditions are simpler, mainly contacted with the coal burial depth; the unit II: the conditions are more complex, predominantly associated with fault structures; the unit III: as a result of the presence of igneous intrusions, coal bed gas content in unit III is the highest within the whole mine; the unit IV: major factor of the conditions is the fold caused by strata uplift, which also leads to a large number of gas emissions. 25 coal and gas outburst accidents all occurred within the unit II of geology.

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

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.

Technology of Strip Gas Pre-Drainage with Boreholes along Coal Seam from Front Traverse

2012 ◽  
Vol 524-527 ◽  
pp. 752-757 ◽  
Author(s):  
Li Wei Chen ◽  
Jin Chao Chen
Keyword(s):  
Coal Seam ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Low Permeability ◽  
Test Results ◽  
Gas Outburst ◽  
Short Period ◽  
Rock Roadway

In order to improve the heading speed of the seam gateway and mitigate the problem of mining maladjustment in high-gas mines and coal and gas outburst mines which are almost low permeability, highly-gas content and it is difficult to eliminate the gas-outburst dangerous by the conventional pre-drainage technologies in a short period. The paper puts forward the view of strip gas pre-drainage with boreholes along coal seam from front traverse of the rock roadway over the seam roof, which can greatly save the time of gas pre-drainage to eliminate gas outburst dangerous by drilling and gas pre-drainage simultaneously for the trips between two traverses. The test results showed that the ratio of roadway driving to gas pre-drainage were increased from 0.31 to 3.6,the speed of driving increased from 50m to 105m per month and the time of roadway drilling and blasting heading per hundred meters from78 days reduced to 19 days. So this technology can greatly mitigate the replacement contradiction of mining and roadway driving.

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