1. Institute for Land Resources, China University of Mining and Technology, Xuzhou, Jiangsu Province 221116, China.
2. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, Jiangsu Province 221116, China.
3. Jiangsu Key Laboratory for Resources and Environmental Information Engineering, China University of Mining and Technology, Xuzhou, Jiangsu Province 221116, China.
4. Department of Civil & Environmental Engineering, University of North Carolina, Charlotte, NC 28223, USA.
5. School of Resource and Earth Science, China University of Mining and Technology, Xuzhou, Jiangsu Province 221116, China.
6. Skapa Mining Services Ltd., Hillbanks, Burray, Orkney KW17 2SX, UK.