In the heart of China’s Yushen mining area, a technological revolution is underway, pushing the boundaries of what’s possible in coal mining. Researchers, led by Jiachen Wang from the China University of Mining and Technology-Beijing, are tackling one of the industry’s most pressing challenges: managing the complexities of ultra-large cutting heights in thick, hard coal seams. Their findings, published in Meitan xuebao, the Chinese Journal of Coal, could reshape the future of coal mining, enhancing safety and efficiency in one of the world’s most energy-intensive sectors.
The Yushen mining area is known for its thick coal seams, but mining these seams at ultra-large cutting heights presents unique challenges. The increased mining space and equipment power lead to strong dynamic loads and high resistance, threatening mining safety. Wang and his team set out to understand the movement laws of thick-hard roofs and the characteristics of support loads in these ultra-high working faces, aiming to control strong mining occurrences and improve safety.
Their study, conducted at the 122104 longwall panel in Caojiatan, revealed that the large mining space, high advance speed, and multi-layer thick-hard roof led to significant dynamic loads. “The roof load is transferred to the ultra-high coal wall rapidly due to support failure, triggering splitting failure of the hard coal,” Wang explained. This rapid transfer of load can cause the hydraulic supports to bear multiple dynamic load impacts, leading to abnormal support conditions.
The team’s findings highlight the unique behavior of thick-hard roofs in ultra-high working faces. These roofs exhibit small deformation before failure, with no separation within the same rock strata group but a clear linkage effect. After failure, the fracture development speed is fast, but the strength deterioration of the broken rock is low, allowing for a stagger-shaped intermittent balance structure.
One of the most significant findings is the co-evolution characteristics of the support load and the roof structure. Before the breakage of the thick-hard roof, the support load is small and mainly distributed in the supporting area of the column. After the breakage, the rock load is transferred downward rapidly, increasing the support load to its maximum resistance. This understanding could lead to the development of more robust and adaptive hydraulic supports, capable of withstanding these dynamic loads and improving mining safety.
The research also proposes a short beam structure model for thick-hard roofs, considering interlayer shear force. This model reveals the principle of small deformation of thick-hard roofs and the mechanism of tensile-shear mixed failure. Understanding these mechanisms could lead to the development of new support strategies and technologies, enhancing the control of surrounding rocks in ultra-high working faces.
The implications of this research are vast. As the energy sector continues to grapple with the need for increased efficiency and safety, these findings could pave the way for new technologies and strategies in coal mining. By understanding the behavior of thick-hard roofs and the characteristics of support loads, mining companies can improve their operations, reduce risks, and enhance productivity.
Wang’s work is a testament to the power of scientific research in driving industrial progress. As the energy sector continues to evolve, so too will the technologies and strategies that underpin it. This research, published in Meitan xuebao, is a significant step forward in that evolution, offering a glimpse into the future of coal mining and the potential for enhanced safety and efficiency. As the industry looks to the future, the insights gained from this research could shape the development of new technologies and strategies, driving progress and innovation in one of the world’s most critical sectors.