Geowebinar Insights
The presentation highlights the activities of the Eurasian Group (ERG), an international mining and metallurgical company operating in 15 countries. Its main assets are located in Africa, Brazil, and Kazakhstan, covering the entire production cycle from extraction to processing and logistics.
Special focus is given to the establishment of ERG’s geological exploration division, launched in 2020. It includes drilling, geophysical, and topographic units, as well as a data processing center. The division’s primary objective is to ensure a sustainable increase in the company’s mineral resource base, particularly in Kazakhstan.
The report outlines exploration priorities for chromite, bauxite, iron, and manganese deposits, as well as diversification projects targeting copper, nickel, cobalt, gold, and rare-earth elements. Expansion of exploration activities beyond Kazakhstan, notably in Uzbekistan, is also planned.
Geological, lithological, and lithogeochemical studies on the Yoktinskaya area of the Middle Urals aimed to identify zones prospective for gold mineralization. The territory lies within the Tagilo-Magnitogorsk megazone and consists of volcano-sedimentary and sedimentary Devonian rocks intruded by dioritic and monzodioritic bodies.
Volcanic and metasomatic rocks underwent intense hydrothermal alteration, forming beresite and propylitic mineral assemblages. Lithogeochemical sampling revealed contrasting arsenic, copper, antimony, and lead dispersion halos spatially associated with zones of secondary quartzites and quartz-sericite metasomatites.
Chemical and spectral analyses indicated an increase in arsenic, molybdenum, and tellurium content with progressive hydrothermal alteration. The Fe–As–Sb association suggests oxidation processes and redistribution of elements within newly formed limonites.
The combined geochemical and structural indicators point to favorable conditions for gold mineralization, making the Yoktinskaya area a promising target for further exploration.
The study explores the optimization of decomposition conditions for carbon-bearing gold–copper sulfide ores for electrothermal atomic absorption determination of gold. The work was conducted at the “Geoanalitik” Center using a Contra 700 spectrometer, providing high analytical sensitivity for low gold concentrations.
More than 50 analytical and sample preparation procedures were compared. Acid digestion using a mixture of HCl, HNO₃, and HF (3:1:1) at 200 °C for 120 min was selected as optimal. Pyrolysis and atomization temperatures were determined as 700 °C and 2000 °C, respectively, ensuring complete matrix removal and graphite tube stability.
Modeling confirmed that under excess argon and chlorine, iron volatilizes from the system, minimizing matrix interferences. Metrological evaluation and interlaboratory testing confirmed the reliability and reproducibility of the developed method for gold determination in carbonaceous sulfide ores.
The study focuses on garnatites from the Murunkell eclogite complex, a key unit for understanding the geodynamic evolution of the Urals. Morphology, mineral and geochemical composition of garnatites formed through metamorphism of ultrabasic and mafic protoliths are examined, with special emphasis on the role of fluids in garnetization and metasomatism.
Chemical analyses reveal increased Al₂O₃ and decreased MgO contents relative to protoliths, as well as migration of alkali elements and rare earths driven by sodic granitoid fluids. Mineralogical observations indicate rapid, near-synchronous garnetization with eclogitization at temperatures up to 600 °C.
The integrated data suggest that the garnatites of the Slyudyana Gorka area originated from oceanic crustal rocks affected by crustal fluids migrating along fracture zones, refining the understanding of metamorphic processes within the Ural orogen.
The study investigates the relationship between the flotation emission characteristics of apatite and the quality of the flotation concentrate. The objective was to identify correlations between emission kinetics and flotation parameters affected by the hydrocarbon chain length and reagent composition.
Experiments were carried out on apatite ore using carboxylic acids from hexanoic to hexadecanoic and oleic acid solutions with Ca²⁺/acid ratios from 1:2 to 1:20. Surface pressure, spreading rate, and recovery values were measured.
Higher surface pressure and spreading rate were found to enhance the rupture of the liquid film between particles and bubbles, increasing apatite recovery but reducing selectivity.
It was established that concentrate quality improves when chemisorbed collector forms dominate over physically adsorbed ones. Lowering the physical adsorption work raises the ratio of useful component content to recovery, confirming the key role of chemical interactions in reagent–mineral binding.
The study presents results on improving the recovery of rare-earth elements from apatite-based raw materials. Considering the increasing demand in high-tech industries and the scarcity of traditional sources, apatite and its processing products are investigated as potential secondary resources.
Conducted within the IPKON research program, the study applies mild leaching conditions to optimize process parameters. The effects of nitric acid concentration, leaching duration, solid-to-liquid ratio, and ultrasonic treatment were examined.
Optimal parameters—nitric acid concentration of 7.9–9 mol/L and leaching time of 20–35 minutes—achieve up to 97.6% recovery of rare-earth elements while reducing impurity content. The results demonstrate the potential to enhance apatite concentrate processing efficiency and reduce operational costs.
Fluorite, a common mineral in hydrothermal parageneses, can serve as a reliable geochronometer for Sm–Nd dating of ore-forming processes. Studies of fluorites from the Streltsovka uranium ore field demonstrate that their Nd and Sr isotope systems enable precise age determination of mineralization. Post-ore fluorites collected from veins cutting volcanic-sedimentary rocks show stable mineral-forming conditions and enrichment in middle and heavy rare-earth elements, favorable for isotopic analysis.
Sm–Nd isochrons yield an age of about 135 ± 1 Ma, consistent with the uranium-bearing stage. The data indicate no significant break between uranium and late fluorite stages of the hydrothermal system, whose duration did not exceed one million years. These results confirm the unity of the hydrothermal process that ended within the Streltsovka volcanotectonic structure in the Early Cretaceous.
The study presents results of integrating remote sensing data with traditional geological investigations to delineate promising placer gold areas. Multispectral satellite imagery of the Bodaibo district enables efficient mapping of Fe²⁺/Fe³⁺ oxidation–reduction zones that correlate with variations in gold occurrence forms.
Mineralogical and geochemical analyses reveal that oxidized zones (Fe³⁺) contain mostly native gold, while reduced zones (Fe²⁺) host telluride and selenide forms. The key mechanism driving gold leaching and migration is the formation of iron thiosulfate—an intermediate product of pyrite oxidation that generates soluble gold complexes.
Placer gold formation is shown to result not only from mechanical disintegration of primary deposits but also from multi-stage chemical reactions within the supergene zone. These processes—oxidation, migration, sorption, and reduction—demonstrate the self-organizing geochemical behavior of the Fe–S–Au system.
The study presents results of integrated mineralogical–geochemical and remote sensing investigations of the Koreysky ore–placer cluster (Zabaykalsky Krai) compared with the Bodaibo region. Natural oxidation of iron compounds (Fe²⁺ → Fe³⁺) alters the mineral composition and creates redox zones controlling the transition of gold from ionic and colloidal forms to native metal.
Gold mineralization occurs in quartz–tourmaline–sulfide stockworks within Jurassic granitoids. In the weathering crust, gold is reduced from telluride and complex forms to metallic state with particle coarsening. Multispectral satellite data enable mapping of Fe³⁺/Fe²⁺ zones correlated with placer gold occurrences.
The study confirms the key role of gold thiosulfate complexes in hypergene processes. The proposed integration of remote sensing and mineralogical–geochemical data is effective for gold potential assessment in mountain–taiga regions with discontinuous permafrost and sulfide mineralization.
