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.
—Gold-bearing dumps of processed pyrite–polymetallic ores of the Ursk ore field (Novo-Urskoe and Beloklyuchevskoe deposits, Salair Ridge) have been studied. Physicochemical modeling of the gold behavior in wastes allowed us to describe quantitatively the gold precipitation process in different horizons of the dumps. In the upper part of the sulfide-rich section, sulfide minerals undergo intense oxidation accompanied by the dissolution of structural and surface-bound gold. Gold redeposition on the pyrite surface (sorption reduction barrier) as a result of electrochemical processes is accompanied by the formation of heavy-metal sulfates and barite. Under the sorption barrier, there is a loose leaching horizon with high humidity, where gold is present in pore solutions as thiosulfate, hydrosulfide, and hydroxo complexes; its content reaches 68 mg/L. In the middle part of the section, composed of compact siliceous sandstones (hardpan), high-grade (up to 973‰) gold forms through the disintegration of thiosulfate complexes, but its content decreases to 10-6 mg/L (lithologic reduction barrier). No visible gold was found in the lower part of the section (soil bed), but its high contents (up to 0.35–0.42 g/L) might be due to the sorption by organic high-molecular compounds, such as humic acids. The morphology and chemical composition of native gold from the gold-containing dumps of processed pyrite–polymetallic ores have been first studied. It is shown that the gold surface has traces of supergene transformations, e.g., gold nano- and microparticles as sponge overgrowth on the gold or barite particle surface or as newly formed gold phases in Fe, Mn, and Al hydroxide films.
Представлена физико-химическая модель преобразования золота в отвале переработки руд Ново-Урского колчеданно-полиметаллического месторождения (Салаирский кряж). За 80 лет существования хвостохранилища переработанные руды в отвалах подверглись процессам механической, физико-химической и биогенной дифференциации и интеграции с образованием горизонта вторичного золотого обогащения. Выделенное золото несет на себе следы гипергенного преобразования с ярко выраженными элементами новообразований. В результате изменения физико-химических параметров среды золото осаждается на восстановительносорбционном и восстановительно-литологическом барьерах. Физико-химическое моделирование поведения Au позволило охарактеризовать процесс его перераспределения и осаждения в различных горизонтах отвала.
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