Minerals Au and Ag in the tailing dump of the processed ores (Salair, Russia)

Abstract

This article provides data on the identification and distribution of Au-Ag minerals in the tailing dump of the processed ores in the pyrite-polymetallic deposit within the Salair ore field (Talmovskiye Sands, Salair). The mineral and chemical compositions of the samples were studied using atomic absorption, mass spectrometry with inductively coupled plasma, X-ray diffractometry, and scanning electron microscopy. We have established that a horizon of secondary enrichment was formed (with Au and Ag contents up to 5,3 and 53.7 g/t, respectively) over a long period of the tailing dump existence (more than 90 years) and at a depth of 0,6-0,8 meters. Gold and silver are unevenly distributed along the section and are present in three species:1) native (Aus, Ags), 2) mineral (acantite, petrovskaite), and 3) isomorphic (sulfides and secondary films). The identified residual and newly formed gold-silver minerals indicate active supergene processes of Au-Ag dissolution, migration, and precipitation. The transformation of native particles occurs through both chemogenic and mechanical processes.