1. Energy School Xi’an University of Science and Technology, Xi’an 710054, China
2. Department of Mining Engineering, Shanxi Institute of Energy, Jinzhong 030600, China
3. College of Mining Technology, Taiyuan University of Technology, Taiyuan 030024, China
4. School of Energy & Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
5. Mining and Designing Branch, China Coal Research Institute, Beijing 100013, China