1. School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, P. R. China
2. International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, Henan Polytechnic University, Jiaozuo 454003, P. R. China
3. WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Kalgoorlie, WA 6430, Australia