The study examines how double-roof-cutting (DRC) mining techniques affect the stability of overlying rock layers, significantly influencing gas migration patterns.
Researchers at Huajin Coking Coal have combined physical modeling, numerical simulation, and field monitoring to investigate the evolution of fractures within rock layers above mining sites. Their findings reveal remarkable differences between traditional mining methods and DRC, particularly concerning how stress is managed throughout the mining process.
Unlike conventional techniques, the implementation of DRC interrupts the typical stress transfer associated with mining, allowing overburden load to be maintained within the central section of goaf. This structural change leads to increased stress concentrations within the mining area, ranging from 17.8 MPa to 26.2 MPa as the mining progresses, demonstrating the potential for enhanced control over gas migration issues.
The research shows substantial reductions—by up to 80%—in the subsidence of roadway roofs compared to methods without roof-cutting, which could translate to improved stability and safety for miners. Heights of the collapse and fissure zones reach 18 m and 40 m, respectively, under DRC conditions, compared to 15 m and 46 m without roof-cutting. Such differences highlight the necessity for adapting mining practices to mitigate risks associated with gas accumulation.
“Under DRC, the heights of the overlying rock collapse and fissure zones are significantly altered, which directly impacts gas migration patterns,” said the authors of the article. Their work offers important insights for the mining industry amid increasing concerns about gas hazards.
The researchers conducted comprehensive tests on the 4502 working face of Huajin Coking Coal, employing advanced techniques to create models of the rock layers. The three-dimensional numerical model utilized acknowledged geological data to simulate the mining process and analyze stress distribution accurately.
This detailed approach demonstrates how well-supported roof structures can greatly reduce the potential impact of overburden collapse and the resultant gas migration challenges, posing new opportunities for safety regulation and operational efficiency.
“The research results can provide a scientific basis for studying the fracture zone of the roof-cutting roadway,” the authors noted, emphasizing the importance of their findings for future mining technologies.
Moving forward, the study of overburden mechanics and gas migration dynamics under varying mining conditions will be fundamental. The research not only enhances the theoretical groundwork but also suggests practical innovations to manage gas exploration and extraction, thereby bolstering safety standards within the coal mining sector.
Given the findings, continuous refinements to mining methodologies, particularly those implementing DRC, stand to support the coal industry’s goals of efficiency and safety. This study advocates for the application of scientific insights to drive advancements within mining practices.