Mineralogy of gold-telluride-sulfide ores of the Kokkiya deposit, Kazakhstan

Gulnara Omarova, Bulat Sukurov, Saltanat Assubayeva, А. Садуов, Symbat Tugambay, Yalkunzhan K. Arshamov

2026

Full text Open access: Hybrid Metadata (CSL-JSON)
DOI 10.33271/mining20.03.053
Data confidence 70 medium
How this score is calculated

It is built from checkable properties of the record itself: whether the article has a DOI, how many independent sources confirmed its data, whether the required fields are filled in, and how recent the latest confirmation is. Disagreement between sources and a missing identifier lower it. A value of 80 or above means the record was published without further checking; 60 to 79 means it is published at reduced confidence, with a manual check advisable. A record verified by an editor by hand is never pushed below 90 by a recalculation. This scores our data about the article, not the article itself.

Abstract

Purpose. To establish the mineral-formforming sequence and clarify the features of gold-telluride-sulfide mineralization at the Kokkiya deposit based on the study of mineral assemblages, typomorphic characteristics of ore minerals, modes of occurrence of native gold and tellurides, and their spatial and paragenetic relationships. Methods. A total of 120 ore and host-rock samples collected from drill core were studied. The analytical methods included optical microscopy in reflected and transmitted light, scanning electron microscopy, electron-probe microanalysis, EDS/WDS analysis, and EDS mapping. Gold fineness and composition were additionally compared with depth, pyrite generations, structural and textural characteristics of the ores, and hypogene and supergene mineral assemblages. Findings. Two main stages of mineralization were distinguished: hypogene and supergene. Four successive stages were identified within the hypogene stage: pre-ore hydrothermal-metasomatic, early pyrite, main telluride-polymetallic, and late pyrite-polymetallic. Pyrite is the principal ore mineral and is represented by several generations differing in morphology and paragenesis. Native gold is associated with pyrite, quartz, sericite, galena, and tellurides. The later stages are characterized by calaverite, petzite, altaite, tsumoite, native tellurium, and Bi-bearing minerals. Gold fineness in intergrowths with altaite and calaverite ranges from 944-977‰, whereas in oxidized ores it ranges from 634-820‰. EDS mapping confirmed the close spatial association of micron-scale gold inclusions with telluride phases. The most intense mineralization is confined to the inner, most strongly altered parts of the metasomatic zonation. Originality. The mineralogical-genetic model of the Kokkiya deposit has been refined by linking pyrite generations, gold fineness, telluride mineralization, and the sequence of ore-forming stages. The distribution of gold and tellurides is shown to reflect the multistage evolution of the hydrothermal system and subsequent supergene alteration. Practical implications. Sericitolites, Te- and Bi-bearing minerals, characteristics of pyrite generations, and gold-telluride associations can be used as mineralogical exploration criteria for evaluating prospective zones and the potential continuation of productive mineralization at depth.