1. School of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
2. College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, Shandong, China
3. Mine Disaster Prevention and Control-Ministry of State Key Laboratory Breeding Base, Shandong University of Science and Technology, Qingdao 266590, Shandong, China