Critical metals (In-Ge-Ga) presence in epithermal systems of Argentina

PAGOLA, M.; JOVIC, S.; GUIDO, D.

Congreso; 16th Biennial Meeting SGA 2022; 2022

The La Mejicana high sulfidation Cu-Au epithermal veins are located in the Famatina mining district, northwestern Argentina.The district contains high sulfidation Cu-Au-(As-Sb-Te) epithermal veins and small Cu-Mo-Au-(As-Sb-Te) mineralized porphyries of the early Pliocene age (Losada-Calderón et al.1994). The district has been known since the mid 19 century and was one of the most important copper, gold and silver producers until 1926. The mining activity has yielded more than 1 Mt of ore, average 3 percent Cu, 80 g/t Ag, and 11 g/t Au from more than 50 veins. The ore is composed of famatinite, enargite, pyrite, quartz,and minor tennantite, tetrahedrite, sphalerite, gold, tellurides, covellite and chalcopyrite.Sahlström et al. (2017) analyzed samples of enargite (ICP-MS-LS) and obtained average Ge concentrations of 717 ppm, and low anomalies for In and Ga. In this abstract we present new ICP analysis of ore samples that shows indium anomalies up to 419 ppm and gallium and anomalies up to 109 ppm. High correlation between In-Ga and Zn is present, this could be related with the presence of sphalerite in the ore. This preliminary data indicates that the enargite could be the main hosting mineral for Ge while In and Ga could be present in the sphalerites. Actually, more detail study is ongoing in order to determine the distributionand presence of these critical elements.