scholarly journals Stress Distribution and Gas Concentration Evolution during Protective Coal Seam Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xingang Niu ◽  
Biming Shi ◽  
Zhigang Zhang ◽  
Yongjiang Zhang
Keyword(s):  
Numerical Modelling ◽  
Coal Seam ◽  
Mining Method ◽  
Coal Seam Gas ◽  
Gas Concentration ◽  
Induced Stress ◽  
Complete Extraction ◽  
Stress Zone ◽  
Seam Mining ◽  
Concentration Evolution

Coal and gas burst is one of the significant and catastrophic hazards in underground longwall operations. To date, the protective coal seam mining has been recognized as the most effective mining method for minimizing or even avoiding the effect of the coal and gas burst. In this paper, numerical modelling and field test were carried out for the longwall operation in Qidong Coal Mine in order to investigate the induced stress and coal seam gas drainage performance in the protected coal seam after the complete extraction of the protective coal seam. It was found that four stress zones can be classified in the protected coal seam being the original stress zone, stress concentration zone, stress relief zone, and recompaction zone. In addition, the monitoring data of gas concentration and volume change in the field agree well with the numerical modelling results.

Experimental Study on Deep Borehole Pre-Cracking Blasting of Drilling through Strata at Low Permeability Seam

2013 ◽  
Vol 868 ◽  
pp. 339-342
Author(s):  
Jian Liu ◽  
Qian Le
Keyword(s):  
Coal Seam ◽  
Control Area ◽  
Low Permeability ◽  
Gas Extraction ◽  
Test Results ◽  
Deep Borehole ◽  
Coal Seam Gas ◽  
Gas Concentration ◽  
Working Face ◽  
Outburst Coal Seam

In the process of roadway excavation in the low permeability outburst coal seam, with drilling through strata in the bottom drainage roadway extracting coal seam gas of control area. In order to improve extraction effect, the method that deep borehole pre-cracking blasting is used to increase the permeability of coal in the drilling through strata seam segment is proposed. The calculation formula on crushing circle and crack circle radius of deep borehole pre-cracking blasting are derived, and the effective loosening radius of blasting is calculated in theory, the research achievements are applied to field test, the test results show that deep borehole pre-cracking blasting permeability improvement technology is carried out in the drilling through strata of the low permeability outburst coal seam, the permeability of coal seam is improved by 180 times, the gas extraction scalar is raised by 8-10 tomes, during the process of roadway excavation, gas concentration of the working face is 0.2%-0.3%, and tunneling footage is increased by 2 times.

Application of Thick Coal Seam Mining Method Prediction Model Based on Artificial Neural Network

2014 ◽  
Vol 962-965 ◽  
pp. 242-246
Author(s):  
Wen Yu Lv ◽  
Zhi Hui Zhang
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Coal Seam ◽  
Prediction Model ◽  
Coal Mining ◽  
Mining Method ◽  
Thick Coal Seam ◽  
Method Selection ◽  
Mining Method Selection ◽  
Seam Mining

Because of thick coal seam mining method selection is not only affected by coal seam geological conditions, but also limited by workers, and not fully utilization of experts` experience, the effect of tradition coal mining method selection methods are not ideal. The thick coal seam mining method prediction model based on artificial neural network (TCSMMPM-ANN) was established through the analysis of thick coal seam mining by using Levenberg – Marquardt (L-M) improved algorithm to train network, the simulation results of network test show that this model can provide a new research idea for thick coal seam mining method optimal selection and face economic and technical index prediction, it will have a broad prospect in thick coal mining.

Induced stress evolution of hydraulic fracturing in an inclined soft coal seam gas reservoir near a fault

2021 ◽  
Vol 88 ◽  
pp. 103794
Author(s):  
Qianting Hu ◽  
Zhizhong Jiang ◽  
Quangui Li ◽  
Wenbin Wu ◽  
Qingguo Wang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Stress Evolution ◽  
Coal Seam Gas ◽  
Gas Reservoir ◽  
Soft Coal ◽  
Induced Stress ◽  
Soft Coal Seam

The Current Situation and Developing Trend of Extremely Thin Coal Seam Mining of China

2013 ◽  
Vol 295-298 ◽  
pp. 2918-2923 ◽  
Author(s):  
Li Ming Zhang
Keyword(s):  
Coal Seam ◽  
Automatic Monitoring ◽  
Development Trend ◽  
Mining Method ◽  
Mining Equipment ◽  
Coal Seams ◽  
Existing Problems ◽  
Thin Coal Seam ◽  
Equipment Development ◽  
Seam Mining

Degree of mechanization of extremely thin coal seam mining is growing, with introducing the main mining method currently used by the different inclination of the extremely thin coal seams in China, focusing on the different mining technology and related ancillary mining equipment development status and existing problems, and discuss the extremely thin coal seam in the future to realize the remote control, automatic monitoring and unmanned mining development trend.

Recent Patents on Thin Coal Seam Mining Equipment

2020 ◽  
Vol 13 (2) ◽  
pp. 99-108
Author(s):  
Yanxiang Wang ◽  
Daolong Yang ◽  
Bangsheng Xing ◽  
Tingting Zhao ◽  
Zhiyi Sun ◽  
...  
Keyword(s):  
Coal Seam ◽  
Underground Space ◽  
Mining Method ◽  
Mining Equipment ◽  
Coal Seams ◽  
Thin Coal Seam ◽  
Recoverable Reserves ◽  
Working Face ◽  
Geological Conditions ◽  
Seam Mining

Background:: China's thin and extremely thin coal seam resources are widely distributed and rich in reserves. These coal seams account for 20% of the recoverable reserves, with 9.83 billion tons of industrial reserves and 6.15 billion tons of recoverable reserves. Objective: Due to the complex geological conditions of the thin coal seam, the plow mining method cannot be effectively popularized, and the drum mining method is difficult to be popularized and applied in small and medium-sized coal mines, so it is necessary to find other more advantageous alternative mining methods. Methods: The equipment integrates mining operations, conveying operations, and supporting operations, and is suitable for mining short and extremely thin coal seam with a height of 0.35m-0.8m and width of 2m-20m. It has the advantages of the low body of the shearer, no additional support on the working face, and small underground space. The mining efficiency of thin coal seam and very thin coal seam can be improved and the mining cost can be reduced. Results: Thin coal seam shear mining combines mining, conveying, and supporting processes together and has the advantages of a low fuselage, no extra support required for the working face, and feasibility in a small underground space. Conclusion: The summarized mining method can improve the mining efficiency of thin and extremely thin coal seams, reduce mining costs, and incorporate green mining practices, which take both mining economy and safety into account.

Numerical Modeling of Subsidence-Induced Stress on the Pipeline in Steep Seam Mining

2013 ◽  
Vol 448-453 ◽  
pp. 3863-3868
Author(s):  
Guo Ming Cheng ◽  
Tong Zu Liu ◽  
Bin Zhi
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Coal Seam ◽  
Maximum Stress ◽  
Measurement Data ◽  
Steep Seam ◽  
Safe Operation ◽  
Induced Stress ◽  
Seam Mining ◽  
The Impact

In China, surface subsidence caused by steep coal seam mining has affected the safe operation of pipelines in recent years. The study site is one coal mine, where the gas pipeline from Shanshan to Urumqi is across. FLAC3D was adopted to study subsidence-induced stress on the pipeline, and the numerical model was calibrated with the measurement data. Visualization of alarm levels on the pipeline was obtained by integrating the usage of Fish function embedded in FLAC3D and Tecplot. The simulations reveal that the stress on the pipeline is closely related to the excavation depth. The stress on the pipeline increases with the excavation depth increasing when mining the 1st, 2nd, and 3rd levels, whereas the stress on the pipeline decreases slightly with the excavation depth increasing when mining the fourth, fifth, and sixth levels. The maximum stress on the pipeline occurs after mining the 3rd level. The possible damage to the pipe is at the upper-right side. Therefore, the results are helpful to prevent and reduce the impact of subsidence on the pipeline.

Study on Gas Control in Coal Mine by Methanotrophic Bacteria M02

2012 ◽  
Vol 602-604 ◽  
pp. 1309-1312
Author(s):  
Jian Xin Tang ◽  
Fei Mao ◽  
Ze Jing Guo ◽  
Jiao Jiao Peng
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Large Scale ◽  
Gas Content ◽  
Methanotrophic Bacteria ◽  
Coal Seam Gas ◽  
Gas Concentration ◽  
Industrial Experiment ◽  
Gas Control ◽  
Control Technologies

Gas control technologies traditionally base on the physical properties of gas. However, making use of microbial technology is another way to deal with coal seam gas. This paper conducted the laboratory test firstly, selected a bacteria M02 to degrade methane efficiently, and the strains were identified as Methylophilus sp.; the conservation of matter experiment verified its ability of methane degradation; then the industrial experiment was implemented in the coal mine underground showed that by the use of methanotrophic bacteria, and the gas concentration of return air, gas content, gas pressure and the index of K1-value had been decreased in different degree. Hence large-scale use of microbial technology on gas control is feasible.

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