An Innovative Non-Pillar Coal-Mining Technology with Automatically Formed Entry: A Case Study
Xingyu Zhang,
Manchao He,
Jun Yang,
Eryu Wang,
Jiabin Zhang,
Yue Sun
Affiliations
Xingyu Zhang
State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China; Department of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, CO 80309, USA; Corresponding authors.
Manchao He
State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China; Corresponding authors.
Jun Yang
State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China
Eryu Wang
Institute of Mining Research, Inner Mongolia University of Science and Technology, Baotou 014010, China
Jiabin Zhang
State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China
Yue Sun
State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China
A non-pillar coal-mining technology with an automatically formed entry is proposed, which reduces the waste of coal resources and the underground entry drivage workload. Three key techniques in this technology cooperate to achieve automatic formation and retaining of the gob-side entry, and to realize non-pillar mining. Constant-resistance large deformation (CRLD) support ensures the stability of the entry roof; directional presplitting blasting (DPB) separates the entry roof and the gob roof; and a blocking-gangue support system (BGSS) integrates the caved rock material as an effective entry rib. An industrial test was conducted to verify the engineering effects of these key techniques. The field application results showed that the retained entry was under the pressure-relief zone due to the broken-expansion nature of the caved rock mass within the DPB height. After going through a provisional dynamic pressure-bearing zone, the retained entry entered the stability zone. The final stable entry meets the requirements of safety and production. The research results demonstrate the good engineering applicability of this technology. By taking the framework of the technology design principles into consideration and adjusting the measures according to different site conditions, it is expected that the proposed non-pillar coal-mining technology can be popularized on a large scale.
