Precise positioning and inert processing of the high-temperature zone in a longwall gob during a mining-stopped period: an application case

ABSTRACT

During a mining-stopped period, coal spontaneous combustion (CSC) may occur in a gob area, which not only causes huge economic losses but also poses a serious threat to the mine’s production safety. To address this situation, a working face in the Chinese Silaogou Coal Mine was considered as an example. With a combination of numerical simulation and field temperature measurements, the spatiotemporal distribution of the temperature in a longwall gob was determined, and the area of potential spontaneous combustion was identified. Furthermore, a dry-ice rapid sublimation unit used for underground fire prevention was developed. The device was successfully applied underground to exert the effect of low-temperature carbon dioxide gas to reduce the coal temperature. The results show that the temperature of the mined-out area near the air intake side of the working face is significantly higher than that of the return side, and the longer the stopping time is, the more obvious the temperature difference is. Within 12 hours of using the generator to inject carbon dioxide, the observed temperatures of the two hot spots dropped from 26.1°C and 26.6°C to 19.1°C and 19.8°C, respectively, and the temperatures hardly rebounded after stopping the gas injection, effectively suppressing the heat storage and oxidation of the coal.

KEYWORDS:

• Coal spontaneous combustion
• high-temperature zone
• longwall gob
• mining-stopped period
• dry-ice phase transformation generator

Acknowledgments

We appreciate the efforts of the Editor and the anonymous reviewers who provided valuable comments and suggestions to improve our research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the China Postdoctoral Science Foundation [2018M630183]; National Natural Science Foundation of China [51874315,52074303].

Notes on contributors

Yueping Qin

Yueping Qin is a professor at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine ventilation, mine fire, mine gas and cooling technology in mine.

Wenjie Guo

Wenjie Guo is a PhD candidate at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine fire is a PhD candidate at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine fire

Wei Liu

Wei Liu is an associate professor at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine fire, mine gas and subway fire.

Hao Xu

Hao Xu is a PhD candidate at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine fire and mine gas.

Yipeng Song

Yipeng Song is a PhD candidate at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine fire.

Liwei Ma

Liwei Ma is a Master candidate at the School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing. His research focuses on mine fire.