Investigation on the potential hazard zone of gas explosion in the goaf under longwall top caving coal mining condition

2022 ◽  
pp. 1-20
Author(s):  
Pengfei Zhu ◽  
Qingzhao Li ◽  
Xiaowen Li ◽  
Guiyun Zhang ◽  
Yachao Zhang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Potential Hazard ◽  
Gas Explosion ◽  
Mining Condition ◽  
Hazard Zone

scholarly journals Surface Subsidence Prediction Method for Coal Mines with Ultrathick and Hard Stratum

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hongkai Han ◽  
Jialin Xu ◽  
Xiaozhen Wang ◽  
Jianlin Xie ◽  
Yantuan Xing
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Prediction Method ◽  
Prediction Equation ◽  
Arbitrary Cross Section ◽  
Surface Subsidence ◽  
Strong Impact ◽  
Subsidence Prediction ◽  
Movement Characteristics ◽  
Mining Condition

Overburden conditions consisting of ultrathick and hard stratum (UTHS) are widespread in China and other countries, but existing surface subsidence prediction methods ignore the strong impact of UTHS on surface subsidence. They are thus not applicable for surface subsidence prediction for coal mining with the presence of UTHS. We conducted actual measurements of surface and UTHS subsidence in the Tingnan Coal Mine. The results showed that under the UTHS mining condition, the required gob dimension is much larger than the empirical value when the surface reaches sufficient mining and that the actual measured maximum value of surface subsidence is much smaller than the empirical value. The UTHS subsidence is approximately equal to the surface subsidence. The movement of UTHS has a strong impact on surface subsidence and has a controlling function for it. It was proposed that surface subsidence could be approximately predicted by calculating the UTHS subsidence. The UTHS movement characteristics were studied using Winkler’s theory of beams on an elastic foundation, the subsidence prediction equation of the main sections in the strike and dip directions was obtained under different mining dimensions, and the subsidence prediction equation of any arbitrary cross section parallel to the two main sections was established. Then, the surface subsidence prediction method for coal mining with the presence of UTHS was developed, and the influences of UTHS thickness, strength, and layer position on the surface subsidence were discussed. The Tingnan Coal Mine was taken as an example, and the subsidence curves of the strike and dip main sections were calculated using different mining dimensions. Subsequently, the surface subsidence after the mining of working faces 204, 205, 206, and 207, respectively, was predicted, and the prediction method was verified by comparing the results with the measured surface subsidence results of working faces 204, 205, and 206.

scholarly journals Gas explosion hazard in underground coal mining in Kuzbass

2019 ◽  
Vol 262 ◽  
pp. 012036
Author(s):  
EA Kozlovsky ◽  
GN Sharov ◽  
AE Kontorovich ◽  
GI Gritsko ◽  
FA Kuznetsov ◽  
...  
Keyword(s):  
Coal Mining ◽  
Explosion Hazard ◽  
Gas Explosion ◽  
Underground Coal Mining

scholarly journals Fuzzy fault tree analysis for gas explosion of coal mining and heading faces in underground coal mines

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879231 ◽  
Author(s):  
Shulei Shi ◽  
Bingyou Jiang ◽  
Xiangrui Meng ◽  
Li Yang
Keyword(s):  
Coal Mining ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Gas Explosion ◽  
Tree Model ◽  
Minimum Path ◽  
Working Face ◽  
Appropriate Treatment ◽  
Fuzzy Fault Tree Analysis ◽  
Underground Coal Mines

During the past decade, gas explosions have been one of the most serious types of disasters in China, threatening the lives of miners and causing significant losses in terms of national property. This article, by constructing the fuzzy fault tree model of gas explosion on the coalface and heading face, deduces the minimum cut sets and minimum path of the fault tree, analyzes the importance of the fault tree structure, and obtains the ratio of gas explosion. The results show that the isolation of gas and heat sources is the most effective way to prevent gas explosion. In addition, a close detection of gas concentration and appropriate treatment can also avoid explosive accidents by reducing the ratio of explosion to below 0.059%, which is the critical value of explosion. The probability of gas explosion occurred in coal working face is about 0%–2.055%, and the most likely probability is 0.059%. However, the probability of gas explosion occurred in heading face is about 0%–8.543%, and the most probability likely to occur is 0.772% which is larger than that in coal working face. The fuzzy fault tree can not only be applied in the analysis of the coal mining gas explosion, but it also provides the theoretical basis for the precaution and prevention of coal mining accidents.

Analysis of Hydrogen Sulfide Impact From Sour Gas Well Blowout in Offshore Platform

2010 ◽  
Author(s):  
Yuan Zhu ◽  
Guo-ming Chen ◽  
Hai-fa Deng
Keyword(s):  
Hydrogen Sulfide ◽  
Good Practice ◽  
Offshore Platform ◽  
Potential Hazard ◽  
Gas Well ◽  
Gas Leakage ◽  
Hazard Zone ◽  
Spatial Environment ◽  
Blowout Preventer ◽  
Sour Gas

Several sour gas leakage accidents have occurred in the offshore platform during the past decades, such as the Kab 121 platform in 2007, which caused serious consequences mainly resulting from the lethal toxicity of hydrogen sulfide (H2S). Under the threat of H2S, it is a challenge to exploit resource in the sour gas filed. Especially during the drilling operation, an abrupt blowout or kick could bring huge amount of H2S, envelop the platform and disperse in the cabins. The present paper is aimed at introducing our analysis of H2S dispersion both in the outer deck and inner mud treatment cabin so as to fully assess the potential poisoning during well blowout. The method we chosen was computational fluid dynamics according to the spatial environment characteristics of the offshore platform. First, we drew a comparison between accident consequences deriving from the wellhead configurations of an opened bell nipple and a sealed rotary blowout preventer (BOP) in the outer deck under various wind directions and speeds. The instantaneous concentrations and hazard zone distributions show that the second configuration is much better from the view of accident control. And the accident severity is much lower when the wind blows from the larboard, not from the prow for both configurations. As a result, the potential hazard zone would not envelop the entire platform with suitable platform position and arrangements of the mud return ditch, accommodation, helicopter deck et al. Then, the simulations of H2S dispersion in the mud treatment cabin were conducted in case of the closed outlet doors, opened outlet doors and sealed cabin with air ventilator working. An immediately dangerous to life level may come up in a short break with the door closed. In such a dangerous situation, H2S can only be made to disperse to other areas through the opened door or effectively ventilated away by means of a ventilator. It is a good practice to isolate the cabins with the potential H2S leakage and install ventilator. And a simple model was proposed to calculate the working time for the ventilator.

scholarly journals Lifi Based Audio Communication for Coal Mine Parameter Monitoring and Automatic Control System

2019 ◽  
Vol 8 (2S5) ◽  
pp. 238-241
Keyword(s):  
Control System ◽  
Coal Mining ◽  
Underground Mines ◽  
Line Of Sight ◽  
White Led ◽  
Essential Factor ◽  
New Information ◽  
Mining Condition ◽  
Audio Communication ◽  
Parameter Monitoring

Li-Fi (Light Fidelity) is a quick and shoddy optical rendition of correspondence. The principle segments of this correspondence framework are a high power white LED which goes about as a correspondence source and a silicon Photo diode which demonstrates great reaction to noticeable wavelength locale filling in as the getting component. An essential factor while planning Li-Fi is Line of Sight (LoS). The LED can be turned on and off to create advanced series of 0s. Information is coded in the light which changes into new information by shifting the glinting rate of the LED. Since the speed of the light is exceptionally quick, the transmitted yield is gotten as voice signs to the specialists at the coal mineshaft. Coal mining and oring includes the disclosure of coal and its troublesome works of extraction, notwithstanding its evacuation and deal in the generation of concrete industry. Most wounds occurring in the underground mines incorporates the falling of rocks, slips and blasts. Harmful gas is produced amid the season of mining and oring forms. The mining laborers are influenced by lung illness by breathing in residue and lethal gas in Coal mining condition. This data is implied to the specialists at the coal mineshaft from the higher authorities through Li-Fi as a voice motions in this work

Safe and Effective Production of Coal Mine Promoted by Coalbed Methane Reclamation

2012 ◽  
Vol 616-618 ◽  
pp. 310-315
Author(s):  
Jun Deng ◽  
Yan Hui Xu ◽  
Hua Jiang ◽  
Shao Bo Hu
Keyword(s):  
Energy Consumption ◽  
Coal Mining ◽  
Coal Mine ◽  
Coalbed Methane ◽  
Coal Field ◽  
Gas Explosion ◽  
High Quality ◽  
Mine Production ◽  
Production Safety

Along with the rapid increase of energy consumption of China, more attention has been paid to the CBM as one kind of clean and high-quality energy. CBM is the greatest threat to the coal mining. If CBM is extracted and well used before coal mining, the environment will be improved and gas explosion accident in coal mine will be obviously diminished. The exploit and advantage of CBM improves the coal field exploration degree and coal mine production safety and efficiency.

Evolution Characteristics of Composite Pressure-Arch in Thin Bedrock of Overlying Strata During Shallow Coal Mining

2019 ◽  
Vol 11 (03) ◽  
pp. 1950030 ◽  
Author(s):  
S. R. Wang ◽  
X. G. Wu ◽  
Y. H. Zhao ◽  
P. Hagan ◽  
C. Cao
Keyword(s):  
Coal Mining ◽  
Structural Characteristics ◽  
In Situ Stress ◽  
Instability Criterion ◽  
Far Field ◽  
Mining Condition ◽  
Evolution Characteristics ◽  
Mechanical Models ◽  
Movement Rules ◽  
Overlying Strata

Under the shallow coal mining condition and based on the cracking and movement rules of the roof in different mining stages, the mechanical models of symmetrical pressure-arch, stepped pressure-arch, rotating-squeezed pressure-arch in the mining field were established. Then, the instability criterion of each pressure-arch structure was derived. Through the similarity material experiment and numerical simulation, the evolution characteristics of the composite pressure-arches in the near- and far-field were revealed. Results show that the stepped pressure-arch in broken blocks of the basic roof was formed when the horizontal principal stress was greater than the in-situ stress. The broken blocks’ sliding could induce roof cutting off and strong weighting load. The structural characteristics of the overlying strata were determined by the thickness of the bedrock. The upper broken rocks formed a symmetrical pressure-arch in the near- and a far-field pressure-arch formed in the mining field. The median periodic broken rocks formed the rotating-squeezed pressure-arch, bearing the load of the loose layers and protecting the mining panel. After all bedrocks breaking, the latter arch foot of the far-field pressure-arch was transferred to the compacted caving zone. This study can provide a theoretical reference for the similar mining engineering.

scholarly journals Applications of Geophysical Logs to Coal Mining—Some Illustrative Examples

Resources ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 11
Author(s):  
Binzhong Zhou ◽  
Hua Guo
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Financial Risks ◽  
Geotechnical Assessment ◽  
Mining Condition ◽  
Natural Gamma ◽  
Potential Applications ◽  
Geophysical Logs ◽  
Mining Projects ◽  
Conventional Logs

Geophysical logs can be used not only for qualitative interpretation such as strata correlation but also for geotechnical assessment through quantitative data analysis. In an emerging digital mining age, such a use of geophysical logs helps to establish reliable geological and geotechnical models, which reduces safety and financial risks due to geological and geotechnical uncertainty for new and existing coal mining projects. This paper presents some examples of geological and geotechnical characterizations from geophysical logs at various coal mines in Australia and India. The applications include rock strength and coal quality estimations, automated lithological/geotechnical interpretation and geophysical strata rating, all based on geophysical logs. These derived parameters could provide input to modelling, control, even ‘digital twin’ generation in a form of geological and geotechnical models as part of the future digital mining. The outcomes can be visualized in 3D space and used for identifying the key geotechnical strata units that are responsible for caving behaviors during longwall mining. This could assist site geologists and planning and production engineers predict and manage mining conditions on an ongoing basis. Both conventional logs such as density, natural gamma and sonic and less common logging data, such as full waveform sonic, televiewer and SIROLOG spectrometric natural gamma logging data are examined for their potential applications. The geotechnical strata classification and rock strengths predicted from the geophysical logs match the laboratory tests, drill core geotechnical strata classification, core photos and the mining condition/behavior observed. These illustrate the usefulness and effectiveness of using geophysical logs for geological and geotechnical characterizations.

The influence of subsidence attributable to coal mining on the environment, development and restoration; some examples from Western Europe and South Africa

2001 ◽  
Vol 7 (1) ◽  
pp. 81-99 ◽  
Author(s):  
F. G. Bell ◽  
D. D. Genske
Keyword(s):  
Coal Mining ◽  
Western Europe ◽  
Longwall Mining ◽  
Ground Surface ◽  
Potential Hazard ◽  
Existing Buildings ◽  
Working Face ◽  
Abandoned Coal Mines ◽  
Problems And Solutions ◽  
Total Extraction

Abstract Coal mining has been practised in some parts of the world, notably western Europe, for centuries and this type of mining has evolved over time as mines became deeper and larger. Today coal is worked primarily by room-and-pillar, and by longwall methods. One of the consequences of mining is subsidence, and it is associated with past and present mine workings. Indeed, old abandoned coal mines worked by the room-and-pillar method, which occur at shallow depth, often present a potential hazard as pillars collapse or voids migrate to the surface. Frequently, the situation is compounded by the fact that such workings are unrecorded. Subsidence prediction in such cases is impossible. In longwall mining, the total extraction of panels takes place, the working face being supported, while support is removed from behind the working face allowing the roof to collapse. Subsidence consequent on longwall mining can be regarded as more or less contemporaneous with mining and is normally predictable. This means that it is possible to develop an area after subsidence due to longwall mining has occurred or to incorporate features into the design of buildings and structures that will accommodate ground movements generated by subsidence. The nature of subsidence can be affected by discontinuities in the surface strata or the presence of superficial deposits. Of course, subsidence can adversely affect existing buildings and structures which do not incorporate special design features. In severe cases of subsidence damage, buildings may have to be demolished. Important buildings may be restored. Another problem associated with subsidence is flooding due to notable lowering of the ground surface. Examples of such problems and solutions are highlighted by the examples given.

Research on Overlying Strata Movement and Deformation under the Conditions of Shortwall and Longwall Mining

2011 ◽  
Vol 90-93 ◽  
pp. 1299-1302 ◽  
Author(s):  
Kuo Li ◽  
Yong Bo Zhang
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Strata Movement ◽  
Damage Level ◽  
Mining Condition ◽  
Movement And Deformation ◽  
Overlying Strata Movement ◽  
Overlying Strata ◽  
Subsidence Curve

We simulate the rock’s movement and defoemation process in the coal mining, and research the overlying strata movement and deformation under the conditions of shortwall and longwall mining. The conclusion of the experiment indicates: with the method of double deck mining, the rock’s damage level in caving layer is more serious, the final subsidence curve presents a tooth geometry. The subsidence curve of fissure and flexure zone is simily with the longwall mining condition.

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