Abstract
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.
Highlights
Published: 14 June 2021Methane present in coal seams has an adverse effect on underground mining plants’work safety due to its release during mining
Desorption, i.e., the process of reversing the consequences of sorption, allows us to calculate the amount of gas desorbed from coal over time. This knowledge is vital from the perspective of mine safety as it enables the identification of spots vulnerable to methane release and eliminates them through intense ventilation
Methane in Polish deposits occurs in an absorbed form, and its content is strictly dependent on the structure of the rock mass and coal deposits in a given region
Summary
Methane present in coal seams has an adverse effect on underground mining plants’. work safety due to its release during mining. The precise calculation of the forecasted methane release from the mining seam and the surrounding rock is of great importance for determining the rigors of safe mining works, including longwall exploitation. There are many methods of predicting methane emissions to workings, including empirical [2,3], simulation [4,5], short-term forecasting models [6,7,8], and computer programs supporting methane hazard monitoring (working in real-time and integrated with coal mine monitoring system) [9,10]. On the example of a particular longwall panel, it was explained how the specific drainage system used can increase methane drainage efficiency
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
