Funding for this research was provided by:
China Geological Survey (1212331599028)
Beijing Publicity Culture High-level Talent Training Subsidy Program (2017XCB031)
National Natural Science Foundation of China (71803182)
Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources (SHJT-17-42.20)
Article History
Received: 11 October 2018
Accepted: 27 December 2018
First Online: 25 January 2019