Investigation of Trace and Critical Elements (Including Actinides) in Flotation Sulphide Concentrates of Kassandra Mines (Chalkidiki, Greece)

Pyrite/arsenopyrite (Py-AsPy), galena (PbS), and sphalerite (ZnS) concentrates from the flotation plants of Olympias and Stratoni (Kassandra mines, Chalkidiki, N. Greece) were investigated for their major, trace, minor, and critical element contents, including actinides associated to natural radioactivity. It is revealed that in addition to the Pb, Zn, Ag, and Au being exploited by Hellas Gold S.A., there are also significant concentrations of Sb and Ga (Sb: >0.2 wt.% in PbS concentrate; Ga:25 ppm in ZnS concentrate), but no considerable contents of Bi, Co, V, or REE. Concerning other elements, As was found in elevated concentrations (>1 wt.% in Py-(As)Py-AsPy Olympias concentrate and almost 1 wt.% in Stratoni PbS and ZnS concentrates) together with Cd (specifically in ZnS concentrate). However, actinides occurred in very low concentrations (U < 2 ppm and Th < 0.5 ppm in all examined concentrates), limiting the possibility of natural radioactivity in the Hellas Gold S.A. products. The concentrations of the natural radionuclides (238U, 232Th, and 40K) are much lower than those of commercial granitic rocks, and thus the associated radioactive dose is insignificant.