1. School of Resources and Geosciences, China University of Mining and Technology, Xuzhou, China
2. Coal Geological Geophysical Exploration Surveying and Mapping Institute of Shanxi Province, Jinzhong, China
3. Shanxi Coal Geological Investigation and Research Institute Company Ltd., Taiyuan, China
4. School of Geography and Information Engineering, China University of Geosciences, Wuhan, China