1. Key Laboratory of Resource Exploration Research of Hebei Province; Hebei University of Engineering, Guangmingnan Street, Handan, Hebei 056038, China
2. China University of Mining and Technology, D11, Xueyuan Road, Haidian District, Beijing 100083, China
3. Instituto de Geociíncias, UFRGS, Avenida Bento Gonáalves, 9500, 91501-970, Porto Alegre, RS, Brazil