Numerical Investigation of Roof Stability in Longwall Face Developed in Shallow Depth under Weak Geological Conditions

Pisith Mao, Hiroto Hashikawa, Takashi Sasaoka, Hideki Shimada, Zhijun Wan, Akihiro Hamanaka and Jiro Oya
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Pisith Mao: Key Laboratory of Deep Coal Resource Mining (CUMT), Ministry of Education of China, School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Hiroto Hashikawa: Laboratory of Rock Engineering and Mining Machinery, Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
Takashi Sasaoka: Laboratory of Rock Engineering and Mining Machinery, Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
Hideki Shimada: Laboratory of Rock Engineering and Mining Machinery, Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
Zhijun Wan: Key Laboratory of Deep Coal Resource Mining (CUMT), Ministry of Education of China, School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Akihiro Hamanaka: Laboratory of Rock Engineering and Mining Machinery, Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
Jiro Oya: Business Planning Department, Mitsui Matsushima Holdings Co., Ltd., Fukuoka 810-8527, Japan

Sustainability, 2022, vol. 14, issue 3, 1-23

Abstract: Developing longwall mining under weak geological conditions imposes a substantial challenge with regard to the higher risk of falling roofs. Maintaining the stability of the longwall face in this aforementioned condition is crucial for smooth operation. Investigating roof conditions in longwall requires detailed study of rock behavior in response to a few key influences. This paper presents the outcome of a numerical analysis of roof stability in shallow depth longwall face under weak geological conditions. A series of validated FLAC3D models was developed to examine the roof condition of the longwall face under the influence of shield canopy ratio, shield resistance force, and stress ratio. The results show that these three key factors have a significant impact on longwall roof conditions, which can be used to optimize its stability. Two distinct mechanisms of the roof caving behavior can be observed under the influence of stress ratio. The countermeasures of reducing face-to-tip distance and cutting width are proposed to improve the roof condition of longwall face under weak rock. The outcomes show a substantial improvement in roof conditions after adopting the proposed method.

Keywords: numerical analysis; weak geological conditions; shallow depth; longwall face; roof stability; shield configurations (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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