[1] China Minmetals Nonferrous Met Co LTD, Beijing 100044, Peoples R China
[2] Univ Sci & Technol Beijing, Key Lab Minist Educ Efficient Min & Safety Met Min, Beijing 100083, Peoples R China
[3] Univ Sci & Technol Beijing, Sch Civil & Resources Engn, Beijing 100083, Peoples R China
[4] Tech Univ Clausthal, Chair Geomech & Multiphys Syst, D-38678 Clausthal Zellerfeld, Germany