Purpose. To study mineralogical and geochemical characteristics of Koktaszhal porphyry copper deposit in order to reveal regularities of porphyry copper ore formation and develop exploration criteria. Methodology. The research applies modern mineralogical and geochemical approaches including XRF (X-ray fluorescence), optical emission spectrometry (ICP-OES), X-ray diffraction analysis (XRD), chemical analysis and phase analysis, as well as analysis of literature and library materials. Findings. Complex mineralogical and geochemical studies of ores of Koktaszhal deposit revealed a complex structure conditioned by porphyry copper mineralization and zonal distribution of its components. Geochemical analysis revealed the prevalence of SiO2, Al2O3 and Na2O in the ore composition. Comparison of oxide and sulphide ore analyses determined a clear spatial and geochemical differentiation of ore components, which reflects different stages of ore formation. It was found that in oxide ore 79.5 % of copper is associated with malachite and azurite, and in sulphide ore, 79 % of copper is associated with bornite. The supergene alteration zone is enriched in Bi, Pb, Co, Ni, which indicates the migration of these elements in the weathering zones, while the sulphide zone is characterized by stable content of Mo, Sb and Ag, which confirms the primary-sulphide nature of the studied mineralization and its formation under low temperature conditions. X-ray diffraction and electron microscopic analyses revealed predominance of quartz, albite, muscovite and other silicates, which confirms the presence of intensive processes of argillisitization and sericitization. The results of thermogravimetric analysis showed high thermal stability of the ore and predominance of thermally stable minerals. The results obtained make it possible to clarify the morphology of ore bodies, to identify geochemical criteria for exploring and evaluating porphyry copper objects, as well as to substantiate directions for ore processing optimization. Originality. The porphyry copper mineralization of Koktaszhal deposit was comprehensively researched using modern analytical and statistical methods. For the first time, a complex interpretation of mineralogical and geochemical characteristics of ores was performed taking into account their spatial variability and influence of tectonic faults. The research identified new genetic features reflecting the stages of fluid mineralization, as well as diagnostic parameters allowing reliable differentiation of ore types. Practical value. The obtained results can be used in ore bodies modelling and planning of exploration works at the stage of assessment and revaluation of reserves of porphyry copper deposits of Central Kazakhstan.
Коpobayeva et al. (Sun,) studied this question.