1. College of Safety and Environmental Engineering, Shandong University of Science and Technology, 579 Qianwangang Rd, Huangdao District, Qingdao 266590, PR China
2. State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, PR China