Geowebinar Insights

The issues of land reclamation after mining and ore-processing activities are examined using the experience of designing large-scale reclamation projects in the Irkutsk Region, including the Cheremkhovo coal deposit and facilities in the Bodaibo district. The study focuses on contradictions and gaps in the current regulatory framework that complicate the preparation and approval of reclamation projects. Environmental legislation and key governmental regulations governing land restoration and the elimination of accumulated environmental damage are analyzed. It is shown that there is no clear regulation defining the required scope of engineering surveys for reclamation design, while criteria for monitoring and evaluating reclamation efficiency are also absent. A significant challenge is the legal status of overburden rocks, which are simultaneously classified as waste and as potential reclamation material, creating additional administrative and financial barriers. These inconsistencies complicate the state environmental review process and often result in negative expert conclusions. The study emphasizes the need to update the regulatory framework in order to improve reclamation efficiency and reduce environmental risks.

The study analyzes the evolution of shaft sinking and operation at the Severouralsk bauxite deposit (SUBR), characterized by complex mining and geological conditions, including high water inflow and rockburst activity. It examines the transition from inclined shafts with low-capacity hoisting systems to vertical shafts equipped with headframes and multi-rope hoisting machines, enabling deeper mining and improved productivity. Particular attention is given to the design and construction of the Cheremukhovskaya-Glubokaya shaft, approximately 1.5 km deep and 8 m in diameter, as well as the implementation of automated ore hoisting systems. Engineering solutions for optimizing skip hoisting are discussed, including the adoption of slide gates, replacement of tail ropes with rubber-cable ropes, and dynamic load control during ore loading. The study shows that reducing metal consumption and abandoning conventional weight-based dosing systems improved reliability and maintainability. The results highlight the importance of integrating engineering and geomechanical approaches in deep mining development.

The study focuses on the mineralogical features of uranium ores from two infiltration-type deposits — Dobrovolnoye (Trans-Ural region) and Khiagdinskoye (Vitim district) — after sulfuric acid in-situ leaching. The main issue addressed is the persistence of residual and redistributed uranium concentrations that reduce the efficiency of metal recovery. The investigation is based on geological and geophysical logging data, laboratory leaching experiments, and detailed mineralogical and electron microscopy analyses of ores and host rocks.

It was established that uranium at the Dobrovolnoye deposit mainly occurs in oxide forms localized in the rock cement and within pyrite concretions. Uranium associated with sulfide mineralization in pyrite shows the lowest leaching efficiency; after technological воздействие, newly formed polycomponent gels and gypsum develop in these zones. At the Khiagdinskoye deposit, uranium predominantly occurs in phosphate form as ningyoite-type gels associated with clay cement. Elevated residual uranium concentrations there are mainly related to weak penetration of leaching solutions into clay-rich host rocks. The results justify the use of oxidizing agents for sulfide destruction and longer exposure of leaching solutions to ore-bearing horizons.

The study examines the geochemical characteristics of granitoids from the South Sarashagan intrusion (Balkhash region, Kazakhstan) as indicators of magma source composition and ore-forming conditions. The Sarashagan area, associated with porphyry copper mineralization within a Late Paleozoic volcanic-plutonic belt, serves as the key geological объект. Due to limited modern geological data and lack of precise geochronology, the research aims to clarify the genesis, age, and metallogenic potential of the intrusion. Methods include petrographic analysis, whole-rock geochemistry, rare earth element distribution patterns, and interpretation of discriminant diagrams. The granitoids are identified as I-type calc-alkaline granites and granodiorites, showing negative Nb anomalies and enrichment in U, K, and Pb. These geochemical signatures indicate magma generation in a subduction-related setting. Element ratios and diagram-based interpretations suggest a mixed mantle–crust source involving both slab-derived basaltic material and sedimentary components. The findings refine the geodynamic framework of the Balkhash region and support the prospectivity of the intrusion for porphyry copper mineralization.

The study focuses on the genesis of rare-metal cryolite-bearing alkaline (A-type) granites and the role of fluid–melt systems in concentrating ore components. The investigated objects include the Katuginskoe, Zashikhinskoe, and Luktandzhekskoe deposits associated with small stock-like intrusive bodies. The key scientific problem concerns the mechanisms of ore formation and the nature of phases responsible for transport and accumulation of rare elements. The research integrates petrographic and mineralogical analyses of natural samples with high-temperature experimental modeling in a gas-pressure vessel. The results demonstrate that cooling induces liquid immiscibility between aluminosilicate and salt-rich aluminofluoride melts, with the latter acting as a concentrator of rare earth elements. Cryolite and associated minerals crystallize at поздних стадиях эволюции системы. Experimental compositions are consistent with natural parageneses, supporting a primary magmatic origin of mineralization. These findings refine genetic models of rare-metal granites and contribute to improved exploration criteria for similar deposits.

The study investigates the basement structure of the Siberian Craton at the junction between the Tunguska superterrane and the Magan terrane within the Nepa-Botuoba anteclise. The research addresses the unresolved nature of the Baikal–Taimyr suture zone, concealed beneath sedimentary cover, and aims to refine the delineation of crustal blocks of different ages. The dataset is based on core samples from three խոր deep boreholes, analyzed using U–Pb zircon geochronology, geochemical, and isotopic methods. Three stages of granitoid formation were identified: Mesoarchean (~2.8 Ga), Paleoproterozoic (~2.0 Ga), and late Paleoproterozoic (~1.88 Ga). Archean gneisses correspond to TTG complexes derived from juvenile crust, whereas younger granitoids originated from diverse sources, including metasedimentary and mixed crustal materials. Geochemical and isotopic signatures indicate a transition from early crustal growth to post-collisional tectonic settings. The results provide new constraints on tectonic zoning and the evolutionary history of the Siberian Craton basement.

The study focuses on the neotectonic structure of the southeastern Gorny Altai, within the Kurai and Chuya intermontane basins and their surrounding ranges. The research targets the northern segment of the Kurai fault zone, which controls the interaction between the basins and the Kurai Range. The scientific problem addresses the reconstruction of seismotectonic activity and the assessment of paleoearthquake parameters in a region of high seismic hazard, relevant for infrastructure planning. The methodology integrates detailed geomorphological mapping (including UAV-based surveys), trenching, radiocarbon dating, and dendrochronological analysis. A system of fault scarps with varying morphology and displacement amplitudes has been identified, formed by multiple Holocene seismic events. At least five paleoearthquakes have been distinguished, with estimates of their age and kinematic characteristics. The formation of dammed lakes is interpreted as an indicator of strong coseismic deformation. The results refine the structural model of the Kurai fault zone and provide a basis for seismic hazard assessment in engineering applications.

The study focuses on ooids—rounded to elliptical mineral grains with concentric internal structures—commonly found in ferruginous and carbonate sedimentary rocks. The investigated area is located in the northwestern Caucasus within the Labino-Maltinsk structural-facies zone. The key scientific problem concerns the lack of a unified model explaining ooid formation and material sources. A комплекс of mineralogical, petrographic, and geochemical methods was applied to characterize composition and textures. The results show that ooids consist of clay minerals, oxyhydroxides, and carbonates, including smectite, chlorite, goethite, and calcite. Four main types are distinguished: ferruginous, carbonate, mixed, and biogenic forms. Ooid formation is controlled by hydrodynamic conditions, oxygenation levels, and multiple sources of matter, including terrigenous input, organic matter degradation, and possibly hydrothermal fluids linked to Early Jurassic magmatism. These findings refine sedimentation and early diagenetic models in marine environments and contribute to understanding mineral authigenesis.

This study presents preliminary palynological and paleontological results from the Rostovka section in the southern West Siberian Plain (Omsk Irtysh region), associated with continental Neogene deposits. The research addresses gaps in palynological data following revisions of the regional stratigraphic framework, particularly for the Peshnevskaya and Livenka formations. Methods include spore-pollen analysis and biostratigraphic correlation based on small mammal assemblages. Two distinct palynocomplexes were identified, reflecting environmental shifts. Palynocomplex 1, linked to the early Pliocene Peshnevskaya interval, shows high diversity of arboreal and shrub taxa and abundant spores, indicating mixed forest ecosystems under warm and humid conditions. Palynocomplex 2, tentatively correlated with the late Pliocene Livenka Formation, is characterized by increased herbaceous taxa and xerophytic communities, suggesting cooler and more arid climatic conditions. These findings refine the stratigraphic attribution of the deposits and contribute to reconstructing the paleoenvironmental evolution of the region.

The study addresses the interpretation of high-uranium zircon in U–Pb geochronology using examples from the Volgo-Ural segment of the East European Platform. The research focuses on clarifying the genesis of zircon characterized by elevated uranium concentrations and low Th/U ratios, as well as assessing its reliability for dating metamorphic and metasomatic processes. Core samples from migmatites and metamorphic complexes were analyzed using isotopic techniques (SIMS, U–Pb dating) alongside crystal-chemical and radiation damage investigations. The results demonstrate that radiation-induced defects and interaction with aqueous fluids play a key role in recrystallization and radiogenic lead loss. High-uranium zircon is shown to form under diverse geodynamic conditions and may record both early and late stages of metamorphic evolution. These findings improve understanding of accessory mineral behavior during metamorphism and enhance the robustness of geochronological interpretations in complex polychronous geological systems.