Title: Optimal position of the open-off cut in the lower coal seam of the overlying goaf

Authors: Guanfeng Chang; Xiao Liu; Peng Li; Yan Zhang

Addresses: School of Mechanics and Optoelectronic Physics, Anhui University of Science and Technology, Huainan, Anhui, 232001, China; State Key Laboratory for Safe Mining of Deep Coal Resources and Environment Protection, Huainan, 232000, China ' China Coal Technology and Engineering Group Shenyang Research Institute Co., Ltd., State Key Laboratory of Coal Mine Disaster Prevention and Control, Fushun, Liaoning, 113122, China ' School of Mining and Mechanical Engineering, Liupanshui Normal University, Liupanshui, 553004, China ' School of Mechanics and Optoelectronic Physics, Anhui University of Science and Technology, Huainan, Anhui, 232001, China

Abstract: An elastic mechanical calculation model was established to optimise the position of the open-off cut in the lower coal seam. Field measurements were employed to evaluate the fractured zone in the surroundings of the open-off cut. As the vertical distance between 22# and 42# coal seams increased, the stress gradually decreased at point M. The normal and shear stresses in the y-axis first increased and then decreased with increased y-axis. Stress peaks concentrated near 30 and 160 m from the stopping line of 22# coal seam under different mining heights, while the minimum stress occurred at about 15 and 165 m. The loosening circle around the open-off cut in 42# coal seam ranged from 2.9 to 4.6 m. Positioning the open-off cut of 42# coal seam about 50 m from the stopping line of 22# coal seam avoided the influence of the protective coal pillar on the stress peak.

Keywords: overlying goaf; lower coal seam; opening-off cut; roof strata; floor strata; stress distribution characteristics.

DOI: 10.1504/IJMME.2026.152403

International Journal of Mining and Mineral Engineering, 2026 Vol.17 No.1, pp.57 - 72

Received: 02 Aug 2025
Accepted: 04 Oct 2025
Published online: 18 Mar 2026 *

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