1. State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
2. School of Mines, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
3. Jiangsu Key Laboratory of Resources and Environment Information Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China