Study of roof stability of the end of working face in upward longwall top coal

  • De-zhong Kong
  • Wei Jiang
  • Yi Chen
  • Zheng-yang Song
  • Zhenqian Ma
Original Paper


Low recovery of longwall top coal caving (LTCC) remains one of the most difficult engineering problems in this mining method and impedes its application. The top coal left in the gob at face end accounts for a large portion of the total coal loss, and the instability of the leftover triangle coal at face end has long been a threat to the safety of miners and the mining equipment. In this paper, based on the engineering background of Ruilong mine, we explore the stability of the roof at the end of the face by using theoretical analysis, numerical simulation, and field measurement. Results reveal that in the inclined longwall top coal caving face, the immediate roof forms an “arch” structure, and the basic roof forms a “masonry beam” structure after the roof collapses; working resistance of the support calculated by the method of ultimate bearing capacity was adequate to meet the requirement of roof load; roof load of coal pillar was related to the length of key block and fracture position; and increasing the size of coal pillar could ensure the stability of both coal pillar and roof.


LTCC, ULTCC Top coal caving at face end Roof stability 



We acknowledge the financial support from the Guizhou University Talent Research Fund (No. 2016-55) and the National Natural Science Foundation of General Program (No. 51574244), (No. 51574093), and (No. 51264004).


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Copyright information

© Saudi Society for Geosciences 2017

Authors and Affiliations

  • De-zhong Kong
    • 1
  • Wei Jiang
    • 2
  • Yi Chen
    • 2
  • Zheng-yang Song
    • 2
  • Zhenqian Ma
    • 1
  1. 1.Mining CollegeGuizhou UniversityGuiyangChina
  2. 2.School of Resource and Safety EngineeringChina University of Mining and TechnologyBeijingChina

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