Geomechanics and Engineering

Techno-Press (테크노프레스)
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Establishment of the roof model and optimization of the working face length in top coal caving mining

  • Chang-Xiang Wang (State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology) ;
  • Qing-Heng Gu (State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology) ;
  • Meng Zhang (State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology) ;
  • Cheng-Yang Jia (State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology) ;
  • Bao-Liang Zhang (School of Architecture & Civil Engineering, Liaocheng University) ;
  • Jian-Hang Wang (Beijing Tiandi Huatai Mining Management Co., Ltd.)
  • Received : 2023.07.18
  • Accepted : 2024.02.07
  • Published : 2024.03.10
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Abstract

This study concentrates on the 301 comprehensive caving working face, notable for its considerable mining height. The roof model is established by integrating prior geological data and the latest borehole rock stratum's physical and mechanical parameters. This comprehensive approach enables the determination of lithology, thickness, and mechanical properties of the roof within 50 m of the primary mining coal seam. Utilizing the transfer rock beam theory and incorporating mining pressure monitoring data, the study delves into the geometric parameters of the direct roof, basic roof movement, and roof pressure during the initial mining process of the 301 comprehensive caving working face. The direct roof of the mining working face is stratified into upper and lower sections. The lower direct roof consists of 6.0 m thick coarse sandstone, while the upper direct roof comprises 9.2 m coarse sandstone, 2.6 m sandy mudstone, and 2.8 m medium sandstone. The basic roof stratum, totaling 22.1 m in thickness, includes layers such as silty sand, medium sandstone, sandy mudstone, and coal. The first pressure step of the basic roof is 61.6 m, with theoretical research indicating a maximum roof pressure of 1.62 MPa during periodic pressure. Extensive simulations and analyses of roof subsidence and advanced abutment pressure under varying working face lengths. Optimal roof control effect is observed when the mining face length falls within the range of 140 m-155 m. This study holds significance as it optimizes the working face length in thick coal seams, enhancing safety and efficiency in coal mining operations.

Keywords

Acknowledgement

This work was supported by the Natural Science Research Project of Anhui Educational Committee (2023AH051187), National Natural Science Foundation of China (52304198), Anhui Provincial Key Research and Development Project (2022m07020006), State and Local Joint Engineering Laboratory for Gas Drainage & Ground Control of Deep Mines (Henan Polytechnic University (No. SJF2208) and Anhui University Excellent Scientific Research and Innovation Team Project (2022AH010051).

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