1. College
of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, P. R. China
2. State
Key Laboratory of Coal and CBM Co-mining, Shanxi Jincheng Anthracite Mining Group Company, Ltd., Jincheng, Shanxi 048000, P. R. China
3. Faculty
of Earth Resources, China University of Geosciences, Wuhan, Hubei 430074, P. R. China