Gas Control Technology under Unstable Disturbance Stress

2015 ◽  
Vol 15 ◽  
pp. 26-34
Author(s):  
Wei Min Cheng ◽  
Lu Lu Sun ◽  
Gang Wang ◽  
Hong Yuan Qu
Keyword(s):  
Control Technology ◽  
Static Loads ◽  
Gas Drainage ◽  
Gas Concentration ◽  
Pressure Step ◽  
Working Face ◽  
Gas Control ◽  
High Level ◽  
Roadway Deformation ◽  
Surrounding Rock Deformation

Under the action of unstable disturbance stress, the stress concentration and roadway deformation are serious when tunneling along the goaf with small pillar while the adjacent working face is mining. This leads to the abnormal gas discharge and the increase of gas emission, and the effectiveness of gas drainage is reduced. In order to eliminate the threat of gas, the dynamic gas control technology of tunneling along the goaf with small pillar under unstable disturbance stress has been researched. The main sources of loads are confirmed by the analysis of dynamic and static loads. Combined with the force analysis of roadway and pillar, the stress superposition level is affected by the relative location of heading face and working face, and the regional characteristics. The measured surrounding rock deformation of A4007 return roadway heading face fits the theoretical analysis and pressure step of working face. The dynamic gas control technology is researched from the aspects of air volume, high-level gas drainage and goaf drainage, and applied in A4007 working face. The gas has been well controlled with the gas concentration of top corner of 0.62% and gas concentration of return current of 0.35%. As a result of the flow control, the gas drainage has not casused spontaneous combustion.

scholarly journals Study on the Optimization of a Gas Drainage Borehole Drainage Horizon Based on the Evolution Characteristics of Mining Fracture

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4499
Author(s):  
Tengteng Li ◽  
Bing Wu ◽  
Baiwei Lei
Keyword(s):  
Coal Mine ◽  
Gas Drainage ◽  
Gas Concentration ◽  
Low Level ◽  
Working Face ◽  
Evolution Characteristics ◽  
Gas Disaster ◽  
Fracture Area ◽  
High Level ◽  
Initial Change

Gas disaster restricts the safety development of coal mine. The technology of high-level borehole gas drainage is an important means to reduce the gas concentration in goaf. In order to determine the best position of the end of gas drainage hole, in this paper, based on the geological conditions of Xinyuan coal mine 31009 working face, a series of numerical simulation is carried out; and through the field test, the dynamic change of gas concentration in different height of borehole is monitored. The results show that: When the working face advances to different distances, there are four characteristic distribution areas in the horizontal direction: the fracture area of the original rock stratum, fracture channel generation and development area, fracture channel mature area and fracture channel closure area. Although the drilling horizon is different, the change of gas concentration in drilling can be divided into four stages: gas stabilization stage, gas initial change stage, gas fluctuation stage and gas re-stabilization stage. The variation of borehole concentration can reflect the evolution characteristics of fracture area. The response time of gas change in different layers is also different. In the gas initial change stage and the gas re-stabilization stage, the low-level borehole first responds. The response of gas change in high-level drilling is a long process, so the effect of high-level drilling is better than that of low-level drilling. For 31009 working face, the best gas drainage layer is 32m, and the field gas drainage has achieved good practical results. This study can provide some guidance for the prevention and control of gas disaster in goaf.

scholarly journals Dynamic Secondary Borehole-Sealing Method for Gas Drainage Boreholes along the Coal Seam

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Qin ◽  
Jialin Xu
Keyword(s):  
Abutment Pressure ◽  
High Water ◽  
Test Results ◽  
Gas Drainage ◽  
Gas Concentration ◽  
Working Face ◽  
Opportune Time ◽  
Sealing Device ◽  
Better Than

Under the influence of advanced abutment pressure, the tightness of a borehole is destroyed, so secondary borehole sealing is needed; however, the opportune time for a secondary borehole sealing is unclear. In addition, current borehole-sealing devices do not have a secondary borehole-sealing functionality. In this paper, an opportunity election model of secondary borehole sealing was established, and a dynamic secondary borehole-sealing device was developed. In working face 3908 of the Kaiyuan Coal Mine, an in situ dynamic secondary borehole-sealing test was conducted. The test results show that the tightness of the boreholes sealed with high-water-expansion slurry is obviously better than that of the boreholes sealed with cement mortar and polyurethane. When a borehole is destroyed by the peak of the advanced abutment pressure, the secondary borehole-sealing measures can significantly improve borehole suction pressure, gas concentration, and gas drainage amount in the advanced abutment pressure loading stage.

Numerical Analysis on Drainage Parameters in a High Drainage Roadway

2015 ◽  
Vol 730 ◽  
pp. 122-125
Author(s):  
Yong Sheng Yan ◽  
Jing Zhao Zhang ◽  
Hong Gang Wang ◽  
Zhen Guo Yan
Keyword(s):  
Numerical Analysis ◽  
Air Velocity ◽  
Gas Drainage ◽  
Gas Concentration ◽  
Numerical Tests ◽  
Obvious Change ◽  
Gas Control ◽  
The Right ◽  
Drainage Ratio

The numerical tests of the optimized drainage parameters in a high drainage roadway were conducted with different inlet air velocities, drainage ratios and integrity lengths. The results show that the upper corner's gas concentration decreases gradually with the inlet air velocity and drainage ratio increasing, while there have not obvious change with the Different Integrity Lengthss. Considering from the gas control and gas drainage, the reasonable inlet air velocity is 1-1.25m/s and the right drainage ratio is about 0.3.

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

Geofluids ◽  
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.

scholarly journals Gas Distribution Mechanism in Goaf during Combined Drainage of Upper Corner Buried Pipeline and Intubation for Thick Coal Seams

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Zhe Li ◽  
Fangtian Wang ◽  
Shuai Ren ◽  
Guannan Liu
Keyword(s):  
Buried Pipeline ◽  
Coal Seams ◽  
Gas Drainage ◽  
Gas Concentration ◽  
Geological Conditions ◽  
Key Issues ◽  
Fluent Software ◽  
Gas Control ◽  
Drainage Effect ◽  
And Control

Abstract The prevention of gas overrun in the panel is one of the key issues on green mining. In this paper, a physical goaf model was established based on the geological production conditions of a coal seam in a coal mine in Henan Province, and the combined drainage technology by burying and spilling pipeline in the upper corner was proposed. The Fluent software was used to simulate the changes of gas mass fraction and flow field distribution when the gas is extracted from the goaf without the gas pipeline, with a single buried pipeline, and with the combination of buried and spilled pipelines. Analysis and simulation showed that in the absence of drainage pipelines, the gas concentrations in both the return airway and the upper corner are up to 1.2%, which failed to meet the gas prevention and control standard on the mine. In the case of gas drainage with a single buried pipeline, the average gas concentration in the return airway was 0.7%, and only the gas concentration in the upper corner was up to 1.1%, which failed to meet the gas control standards on the mine’s panel. However, the maximum gas concentration in the combined drainage was reduced from 1.1% to 0.6%, which indicates that the technology can greatly reduce gas concentration, but there is still a gap from the mine’s gas control standard. Therefore, the impacts of the lengths of pipelines buried in different goafs on the gas drainage effect in the goaf were studied, and it was concluded that the reasonable length of pipelines buried in the goaf under the geological conditions was 20 m. This technology not only solves the problem of gas overrun in the panel but also realizes the utilization of gas resources in the goaf. The research results are of guiding significance for pipeline laying and the drainage technology in the upper corners on the U-shaped ventilation panel.

Study on Comprehensive Gas Control Technology of High-Gas Fully Mechanized Caving Face

2012 ◽  
Vol 610-613 ◽  
pp. 655-660
Author(s):  
Weimin Cheng ◽  
Hai Yang Wang ◽  
Lu Lu Sun
Keyword(s):  
Control System ◽  
High Efficiency ◽  
Control Technology ◽  
Actual Situation ◽  
Gas Drainage ◽  
The Face ◽  
Gas Control

In order to comprehensively control the gas of 1151(3) fully mechanized caving face in Xieqiao coalmine scientificly and efficiently, combining the actual situation of the face, gas drainage technologies such as roof drilling, drilling along seam, gas drainage in upper corner, roof drainage roadway had been applied and a comprehensive gas control system was formed gradually. Gas problems of the face have been solved completely and safety and high efficiency of the workface has been ensured.

Study on Gas Flow Law in Goaf of Huangling No.1 Mine Fully-Mechanized Face

2014 ◽  
Vol 1010-1012 ◽  
pp. 1548-1553
Author(s):  
Tian Xuan Hao ◽  
Meng Liu
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Sampling Method ◽  
Concentration Field ◽  
High Fracture ◽  
Gas Concentration ◽  
Working Face ◽  
Fluent Software ◽  
Gas Control ◽  
Important Basis

The gas concentration field in goaf of Huangling No.1 Mine 304 fully-mechanized face was simulated numerically by FLUENT software with high fracture drilling or not. The results of numerical simulation were confirmed by fixed sampling method of immersed tube in goaf. Thus, the law of gas concentration field was gained, which provides the important basis for gas control of working face.

scholarly journals Goaf Gas Control Improvement by Optimizing the Adjacent Roadway Large-Diameter Boreholes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wei Wang ◽  
Zongxiang Li ◽  
Hongming Yu
Keyword(s):  
Gas Flow ◽  
Large Diameter ◽  
Control Process ◽  
Utilization Efficiency ◽  
Shanxi Province ◽  
Engineering Practice ◽  
Permeability Model ◽  
Gas Concentration ◽  
Working Face ◽  
Gas Control

This study introduced gas control technology in goaf using adjacent roadway large-diameter (550 mm) boreholes to control gas accumulation in the upper corner of a fully mechanized working face in high-gas coal seams. The gas control process in the upper corner and gas interception in goaf by large-diameter boreholes was analyzed using the CFD model of the gas flow in goaf. The latter considered the control equation of gas flow, the established permeability model of goaf, and the gas emission law in goaf. Using the 2-105 working face of the Tenghui Coal Mine, Shanxi Province, China, as a case study, the distribution patterns of gas concentration and flow field in the goaf for various extraction flow parameters and different positions of boreholes were numerically simulated. The dependences between various locations, drainage flows, and the gas concentration in the upper corner were determined and fitted by engineering equations. The evolution pattern of the spontaneous combustion zone in the goaf under the drainage conditions was also analyzed. The optimal borehole configuration parameters ensuring the extraction flow rate exceeding 3 m·s−1 and the effective gas control in the upper corner of the working face at a distance of 5 m–15 m behind the working face were identified. The engineering practice proved the feasibility of gas control in the goaf using the adjacent roadway large-diameter borehole. The gas concentrations in the return airflow and the upper corner of the working face were kept below 0.65 and 0.8%, respectively, to ensure production safety and improve the gas utilization efficiency.

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