STUDIES ON THE OCCURRENCE STATE OF ASSOCIATED GOLD AND SILVER IN THE XIAOTIESHAN POLYMETALLIC ORE DEPOSIT, BAIYIN

摘要

After the material compositions of 6 comprehensive large samples were studied, gold of the massive Cu-Pb-Zn ores and the disseminated Cu-Pb-Zn ores mainly occurs as an independent mineral. Mainly, it is Ag-Au ore, then Au-Ag ore. The Ag-bearing minerals like tetrahedrite and bornite (tentatively named) have been firstly discovered. The grain sizes of the Au minerals are mainly middle fine grained, and most of them are concentrated in 10-74/im. The research result indicates that the Au minerals were later than galena, and the formation temperature is the lowest. Au minerals of Ag-Au ore commonly intergrew with galena, or filled along the fissures and interstices of the early-formed pyrite or of arsenopyrite independently, or replaced the early-formed sulphides like chalcopyrite and