scholarly journals Optimum Layout of Multiple Tree-type Boreholes in Low-Permeability Coal Seams to Improve Methane Drainage Performance

2021 ◽  
Vol 9 ◽  
Author(s):  
Liang Zhang ◽  
Qingjie Qi ◽  
Kai Deng ◽  
Shaojie Zuo ◽  
YingJie Liu
Keyword(s):  
Coal Mine ◽  
Underground Mining ◽  
Fracture Permeability ◽  
Coal Seams ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Drainage Zone ◽  
Effective Drainage ◽  
Tree Type ◽  
Multiple Tree

Extracting coal mine methane (CMM) is important for underground mining safety. The tree-type borehole drainage (TTBD) technique can effectively remove methane from coal seams. Determining a suitable drilling pattern for multiple tree-type boreholes will promote the efficient application of this technique in coal mines. Aimed at solving the problem that the optimum methane extraction layout for multiple tree-type boreholes is unclear, this study first constructed a full-coupled thermo-hydro-mechanical model to simulate methane flow in coal. This model and data from a coal mine were used to investigate the effect of multiple tree-type borehole layouts, tree-type borehole spacing, different Langmuir volume and different Langmuir pressure constants, and initial coal permeabilities on CMM drainage. The results show that the different tree-type borehole layouts result in significant differences in drainage and that the use of a rhombic sub-borehole layout can reduce the methane pre-drainage time by up to 44.4%. As the tree-type borehole spacing increases, the total time required for pre-drainage increases as a power function. As the Langmuir pressure constant, the fracture permeability, or the matrix permeability increases, the effective drainage zone expands. The effective drainage zone also expands when the Langmuir volume constant decreases but all these changes are accompanied by a shortening of the drainage completion time. These results can provide a reliable basis for optimizing tree-type borehole drilling layouts.

Effects of permeability anisotropy on coal mine methane drainage performance

2021 ◽  
Vol 86 ◽  
pp. 103733
Author(s):  
Zhen Lou ◽  
Kai Wang ◽  
Jie Zang ◽  
Wei Zhao ◽  
Binbin Qin ◽  
...  
Keyword(s):  
Coal Mine ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Permeability Anisotropy

scholarly journals CBM Resources Estimations for the Development of Coal Mine Methane in the Asturian Central Basin, Spain

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1404
Author(s):  
Pablo Cienfuegos-Suárez ◽  
Efrén García-Ordiales ◽  
Diego Alonso-Fernández ◽  
Jorge Enrique Soto-Yen
Keyword(s):  
Coal Mine ◽  
Coalbed Methane ◽  
Technological Development ◽  
Gas Content ◽  
Central Basin ◽  
Economic Interest ◽  
Coal Seams ◽  
Coal Basin ◽  
Coal Mine Methane ◽  
Made In

New technological development and a best knowledge of the basin allow to have justified expectation to find coalbed methane reserves. Measurements of gas content in unexploited coal seams are made in order to estimate the CBM could revive the economic interest of the Asturian Central Coal Basin (ACCB). According to first estimations based on the studies accomplished, the minimum resources of coalbed methane in the whole of the Asturian Central Coal Basin are in the order of 25,000 Mm3 and the gas content of the coal seams range from 6 m3 to 14 m3/t. The introduction should briefly place the study in a broad context and define the purpose of the work and its significance.

scholarly journals Analysis of methane hazard in longwall working equipped with a powered longwall complex

2020 ◽  
Vol 174 ◽  
pp. 01011
Author(s):  
Leszek Sobik ◽  
Jarosław Brodny ◽  
Gennady Buyаlich ◽  
Pavel Strelnikov
Keyword(s):  
High Performance ◽  
Underground Mining ◽  
Practical Knowledge ◽  
Mining Operation ◽  
Mining Area ◽  
Hard Coal ◽  
Coal Seams ◽  
Methane Drainage ◽  
High Degree ◽  
Advanced Model

Most of currently exploited hard coal seams has a very high degree of methane saturation. Consequently, the mining process of such deposits generates substantial amounts of methane. This in turn increases the risk of fire and/or explosion of this gas. Methane hazard is currently one of the most dangerous threats occurring in the process of underground mining exploitation. In particular, this applies to longwall excavations where the rock mass mining process generates the highest level of this gas. Commonly used high-performance longwall complexes cause an increase in the amount of coal output, which also causes an increase in the amount of methane released. In order to prevent hazardous concentrations, appropriate ventilation systems and atmosphere monitoring in mining excavations are used. The paper discusses currently used methods designed to limit risks caused by methane such as methane drainage. The paper presents an example of the use of an innovative method of analysing methane risk status and measures aimed at minimizing it. The developed method is based on air parameters in the actual mining area which were then used to create a method of ventilation for such excavations. The method combines advanced model analysis and experience of mine employees and integrates academic and practical knowledge. The main objective of the activities presented in the article was to improve the safety of mining operation

Coal Mine Methane Drainage and Comprehensive Utilization in China

2013 ◽  
Vol 295-298 ◽  
pp. 3023-3026 ◽  
Author(s):  
Qing Ye ◽  
Yan Pi ◽  
Zhen Zhen Jia ◽  
Hai Zhen Wang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Chemical Production ◽  
Efficient Utilization ◽  
Effective Utilization ◽  
Coal Mine Methane ◽  
Development Stages ◽  
Methane Drainage ◽  
Coal Seam Methane ◽  
Methane Utilization

According to situation of coal mine methane drainage and utilization, the five experienced development stages of coal mine methane drainage technology was summarized, the reasons of low rate of coal mine methane drainage were analyzed. Coal-seam methane utilization was analyzed from methane purification, methane generating electricity, chemical production, methane for civil utilization and utilization as automobile fuel etc. With the coal seam methane drainage quantity is more and more, the emissions requirements is more and more strict, so the emission reduction and effective utilization of this energy is important to accelerate efficient utilization of coal methane, reduce greenhouse gas emissions, protect environment, alleviate the supply contradiction of energy and realize sustainable development of coal mine etc.

scholarly journals Possibilities of Capturing Methane from Hard Coal Deposits Lying at Great Depths

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3542
Author(s):  
Nikodem Szlązak ◽  
Justyna Swolkień
Keyword(s):  
Underground Mining ◽  
Drainage System ◽  
Hard Coal ◽  
Coal Seams ◽  
Second Stage ◽  
Methane Drainage ◽  
Coal Deposits ◽  
Significant Difference ◽  
Flammable Gas ◽  
Deposition Depth

Methane present in coal seams is a natural hazard present during the exploitation of underground mining plants. It is an explosive and flammable gas that is released into mining excavations, and it is necessary to reduce its concentration. Capturing methane while preparing extraction is virtually impossible due to the low permeability of coal resulting from its deposition depth. After the beginning of exploitation and disrupting the seam’s structure, methane is released into mine air. The most common method of minimizing gas released into ventilation air is draining the rock mass. This method allows achieving the desired ventilation parameters but requires appropriate mining techniques in hazardous areas. The article presents the example of methane capture during the operation in the longwall B-15 with an overlying drainage gallery. The authors have highlighted an example of the longwall B-15 that when using this particular drainage method, allowed capturing twice the amount of methane forecasted, thus increasing the efficiency of methane drainage. At the preliminary stage of longwall development, the amount of methane charged by the drainage system had relatively low values, reaching 15 m3/min. In the next few months, these parameters increased and varied between 35 to 55 m3/min. A significant difference in methane capture appeared in the second stage of exploitation, where the highest value of captured methane reached 82 m3/min. This particular longwall example shows that it is crucial to properly design the drainage system for seams with high forecasted methane release. It is worth remembering that using a drainage gallery provides an increase in the methane capture from the desorption zone areas, thus increasing total methane capture in comparison to forecasts.

Analysis of Coal Mine Methane Development Technology in China

2013 ◽  
Vol 868 ◽  
pp. 326-330
Author(s):  
Xin Sun ◽  
Bai Sheng Nie ◽  
Sheng Chu Huang ◽  
Shou Tao Hu
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Coal Bed ◽  
Pressure Relief ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Soft Coal ◽  
Methane Extraction ◽  
Development Technology ◽  
Soft Coal Seam

This paper introduces occurrence characteristics of coal bed methane in China, and analyses the influence of coal seam permeability on coal mine methane extraction. In addition, it presents the mechanism of increasing permeability by pressure relief. Lastly, the methane extraction technologies are discussed, and the applicable conditions of these technologies are analyzed. It is seen that choosing appropriate methane drainage technology, often in combination with several technologies including ground drilling, underground drilling, and pressure relief and permeability improving measures, is crucial for geological complex coal seam, especially low permeability soft coal seam.

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