1. School of Mines, China University of Mining and Technology, Xuzhou 221116, China
2. Zhaolou Coal Mine, Yanmei Heze Energy and Chemical Co., Ltd., Xuzhou 274700, China
3. School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
4. School of Resource Environment and Safety Engineering, University of South China, Hengyang 412001, China
5. School of Civil Engineering, The University of Queensland, Brisbane, QLD 4072, Australia