Title: A new roof cutting technique to enhance the stability of underground tunnels and improve the recovery rate of coal resources: a case study

Authors: Rui Gao; Yongqing Lin; Zengchao Feng; Xianglin Dai; Xiangbin Meng

Addresses: College of Mines, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China ' Key Laboratory of In-situ Property-Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China ' Key Laboratory of In-situ Property-Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China ' College of Mines, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China ' College of Mines, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China

Abstract: Narrowing the protective coal pillar width in roadways can enhance coal resource recovery rates. Yet, this adjustment leads to narrower coal pillars, triggering instability in the adjacent rock and significant area deformation issues. To optimise the coal pillar width and maintain the stability of underground roadway, a new directional roof cutting technique was proposed. This technique was used to form directional, continuous, glossy, long-distance crack through the cooperation of the perforating pipe, perforating charge, and dynamite for directional cracks made by composite blasting at different times and spaces. This technique as an integral part of the 'ground hydraulic fracturing + X' integrated technology, offers a pathway to stress relief underground. Due to its strong directional fracturing and excellent permeability in rock formations, it significantly expands the applicability of the 'ground hydraulic fracturing + X' technique in tunnelling and rock engineering. This technology provides scientific guidance for underground mining in ultra-thick coal seams.

Keywords: coal resource; roadway stability; surrounding rock control; composite blast; directional crack forming.

DOI: 10.1504/IJMME.2023.137374

International Journal of Mining and Mineral Engineering, 2023 Vol.14 No.4, pp.397 - 420

Received: 17 Jul 2023
Accepted: 05 Jan 2024
Published online: 14 Mar 2024 *

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