1. Department of Mining Engineering, Shanxi Institute of Technology, Yangquan 045000, China
2. Shandong Polytechnic College, Jining 272067, China
3. Department of Mining Engineering, Balochistan University of Information Technology, Engineering and Management Sciences (BUITEMS), Quetta 87300, Pakistan
4. Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China