1. College of Mining, Guizhou University, Guiyang, P R China
2. Guizhou Key Laboratory of Comprehensive Utilization of Non-Metallic Mineral Resources, Guizhou University, Guiyang, P R China
3. National and Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas, Guizhou University, Guiyang, P R China