Air-leakage Model and Sealing Technique With Sealing–Isolation Integration for Gas-drainage Boreholes in Coal Mines

2020 ◽  
Vol 140 ◽  
pp. 258-272
Author(s):  
Yongjiang Zhang ◽  
Quanle Zou ◽  
Lindong Guo
Keyword(s):  
Coal Mines ◽  
Air Leakage ◽  
Gas Drainage ◽  
Leakage Model

Mining Gassy Coal Seams with a Three-Entry Panel Layout

2012 ◽  
Vol 524-527 ◽  
pp. 613-617
Author(s):  
Jun Hua Xue ◽  
Sheng Xue
Keyword(s):  
Coal Mine ◽  
Methane Concentration ◽  
Ventilation System ◽  
Coal Mines ◽  
Distribution Characteristics ◽  
Coal Seams ◽  
Gas Drainage ◽  
Gas Emissions ◽  
Underground Coal Mines

To address the issue of high gas emissions in mining gassy coal seams in underground coal mines, the concept of a three-entry panel layout with a retained goaf-edge gateroad and a “Y” type ventilation system is introduced in this paper. With the layout and ventilation system, distribution characteristics of methane concentration in the panel goaf is analyzed, technologies of gas drainage with boreholes drilled from the retained goaf-edge gateroad and into stress-relieved overlying and underlying seams are described, and an application case of such layout in a coal mine is also presented in this paper.

scholarly journals Improvement of Gas Drainage Efficiency via Optimization of Sealing Depth of Cross-Measure Boreholes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pu Li ◽  
Zhiheng Cheng ◽  
Liang Chen ◽  
Hongbing Wang ◽  
Jialin Cao
Keyword(s):  
Stress Concentration ◽  
Drainage System ◽  
Stress Concentration Zone ◽  
Concentration Zone ◽  
Air Leakage ◽  
In Situ Tests ◽  
Gas Drainage ◽  
Drainage Borehole

The sealing depth of a gas-drainage borehole is critically important as it directly affects the efficiency of the whole drainage system. In order to determine the shortest reasonable sealing depth, in this paper, a theoretical drainage model using different sealing depths was proposed. Based on theoretical analysis presented, two parts of the fractures system surrounding the drainage borehole were proposed, i.e. the fractures induced by roadway excavation and the fractures induced by borehole drilling. A series of geological in-situ tests and simulations research were conducted to determine the stress and fracture distributions in the surrounding rock of the borehole. The depths of crushing zones, plastic zones and stress concentration zones were determined as 5 m, 2 m and 12 m, respectively. Meanwhile, stress simulation shows that the depth of the stress concentration zone was 12 m from the roadway wall and the stress peak was located at the depth of 8 m, which can be verified by the results of drilling penetration velocity analysis. To determine the optimum sealing depth, gas drainage holes with different sealing depths were drilled in the field. The field results revealed that the crushing zones were the main area for air leakage, and the stress concentration induced by roadway excavation assisted in the reduction of air leakage. Therefore, the optimized sealing depth should both cover the plastic zone and the stress concentration zone. The research achievements can provide a quantitative method for the determination of optimum sealing depth in cross-measure drainage boreholes.

Sign in / Sign up

Export Citation Format

Share Document