1. Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221008, China
2. School of Resources and Geoscience, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
3. Department of Mining and Materials Engineering, McGill University, 3610 University, Montreal, Quebec, Canada H3A 0C5