ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Geohazards and Georisks
This article is part of the Research TopicNatural Hazards Accompanying Underground Exploitation of Mineral Raw MaterialsView all 10 articles
Study on the Formation Mechanism of Intense Rock Pressure in Fully Mechanized Top-Coal Caving Mining Under Conditions of Large Burial Depth and Thick Unconsolidated Layer
Provisionally accepted
- 1Yulin University, Yulin, China
- 2Xi'an University of Science and Technology, Xi'an, China
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With increasing coal seam burial depth and mining intensity, deep-well mining faces prominent rock pressure hazards that threaten safe and efficient production. In the Yanbei Coal Mine of the Huating Mining Area, the overlying strata of the 5th coal seam present a "two hard and one soft" structure, composed of two hard key strata (fine sandstone and siltstone) and one soft coal seam, which significantly affects the behavior of strata movement. To examine the role of key strata in fully mechanized top-coal caving (FMTC), a physical similar material simulation was performed under three mining conditions. Results indicate that when a single working face is mined, pressure on the face is relatively small and stable, as key strata only bend and subside without fracturing. When two working faces are mined simultaneously, the key strata fracture, producing rapid increases in stress and impact loads that intensify the pressure environment. With further mining, pressure magnitude depends mainly on the suspended length of the key strata and the size of fractured blocks. The study also shows that "small structures" and "large structures" coexist in the stope. Small structures, formed by immediate roof breakage, locally control overlying strata damage. Large structures, formed by key strata breakage, dominate pressure transfer across multiple working faces and become the main load-bearing system after failure. Before breakage, the control range of key strata is influenced by working face width and the presence of section coal pillars. When width is fixed, whether a core area exists in the coal pillar becomes the decisive factor. Field practice in Yanbei Coal Mine confirms that removing the core area from section coal pillars can mitigate dynamic and static loads released by key strata failure, reduce the risk of intense rock pressure, and ensure the stability and safety of working faces during deep mining operations.
Keywords: Deep-well Mining, Key strata, Section coal pillar, Intense Rock Pressure, Fully mechanized top-coal caving
Received: 23 Sep 2025; Accepted: 19 Nov 2025.
Copyright: © 2025 Wang, Fu and Guo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Jiayao Fu, jy_fu@stu.xust.edu.cn
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