ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Geohazards and Georisks
Volume 13 - 2025 | doi: 10.3389/feart.2025.1669450
Research on hydraulic fracturing technology for the comprehensive management of gas gathering in the overhanging roof and upper corner of the upper end head
Provisionally accepted
- Xi'an University of Science and Technology, Xi'an, China
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Aiming at the problems of large overhanging roof and abnormal gas concentration at the upper corner(The 'upper corner' refers to the triangular zone located 3–5 m along the support cutting line at the return air end of the working face) in the 143 working face of B42 coal seam in Donggou Coal Mine, this study systematically investigated the application of hydraulic fracturing technology for comprehensive management. First, we measured the gas concentration at the upper corner and analyzed the causes of frequent over-limit, revealing that the large overhanging roof (strike length 27–30 m, dip width 10–15 m) and insufficient roof collapse were the key factors. Then, a drilling scheme was designed, including downward boreholes parallel and perpendicular to the coal pillar along the roadway, to implement hydraulic fracturing. Key parameters such as fracturing pressure (11.5–35 MPa), fracture propagation radius (optimal 6 m), and single fracturing duration (10–30 min) were determined based on rock mechanical properties (e.g., tensile strength of roof strata) and theoretical calculations. After two hydraulic fracturing treatments, the overhanging roof area was significantly reduced (strike length 5–8 m, dip width 2–5 m). The gas concentration at the upper corner stabilized at 0.18%–0.3%, the goaf gas concentration (10–60 m range) at 0.6%–1.0%, and the return airflow gas concentration at 0.22%. Mechanically, hydraulic fracturing-induced fractures promoted roof collapse, guiding free gas in the upper corner to migrate into the caving-fracture zone(The 'fracture zone' is the rock stratum above the caving zone in the goaf), thereby meeting coal mine safety standards. This study provides a theoretical and technical basis for gas control in similar high-gas mines with hard roofs.
Keywords: hydraulic fracturing, upper end head, upper corner gas, drilling, Coal mine safety
Received: 25 Jul 2025; Accepted: 19 Aug 2025.
Copyright: © 2025 Zhang, Guo, Fu, Wu and Ji. 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: Pei Zhang, Xi'an University of Science and Technology, Xi'an, China
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