1. Faculty of Safety Engineering, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China
2. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, No. 1 University Road, Xuzhou, Jiangsu 221116, PR China
3. Department of Mining Engineering, Shanxi Institute of Technology, Yangquan 045000, Shanxi, China
4. School of Resource, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, Hunan, China