Vol 277

Soil pollution by oil and petroleum products is a serious environmental problem, especially relevant for industrialized regions. Microbiological remediation based on the use of oil-oxidizing microorganisms is a promising method of restoring polluted soils. The aims of the study are to develop a composition and assess the effectiveness of a specialized bio-based product adapted to the climatic conditions of northwest Russia. Bacterial strains capable of utilizing petroleum products as the only carbon source have been selected and cultivated. Based on laboratory tests, a consortium of microorganisms was selected, including strains of Acinetobacter sp. (VKM B-3202), Rhodococcus erythropolis (VKM Ac-858 T) and Pseudomonas alcaligenes (VKM B-1295), and their growth activity was evaluated. Three biologics compositions have been developed, differing in the proportions of bacterial suspensions by volume, and the technology of their application to oil-contaminated soils has been determined. The effectiveness of cleaning soils contaminated with oil and petroleum products (gasoline, diesel fuel, oil products from a spill at the Tammisuo railway station (Vyborg) at temperatures of 10-20 °C, typical for the climate of the region, was studied in laboratory conditions. At a temperature regime of 20±1 °C and natural soil moisture, after 60 days of the experiment, the maximum concentration reduction rates reached 75.59 % for crude oil, 71.97 % for oil products from the spill, 90.53 % for diesel fuel, 75.81 % for gasoline. At a temperature of 10±1 °C – 40.62 % for crude oil, 49.58 % for oil products from the spill, 69.06 % for diesel fuel, 68.10 % for gasoline. The results of the study confirm the effectiveness of the developed bio-based product for oil-contaminated soil purification in the climatic conditions of northwestern Russia.

The Arctic shelf zone is an important research target due to its significant hydrocarbon potential. A study of the physical properties (density, elasticity, elastic anisotropy index, specific acoustic impedance, and porosity) was conducted for core samples from six wells in the South Barents Basin: Admiralteyskaya-1, Krestovaya-1, Ludlovskaya-1, Shtokmanskaya-1, Arkticheskaya-1, and Severo-Kildinskaya-82. The sample collection consists of sandstones, siltstones, and limestones. Core analysis revealed that rocks from non-productive wells (Arkticheskaya-1, Admiralteyskaya-1, and Krestovaya-1), located in the central part of the South Barents Basin and within the Admiralty High, differ in their physical and petrographic properties from rocks in gas and gas-condensate wells (Shtokmanskaya-1, Severo-Kildinskaya-82, and Ludlovskaya-1), located near the boundaries of the South Barents Basin. Core samples from productive wells (Shtokmanskaya-1, Severo-Kildinskaya-82, Ludlovskaya-1) exhibit lower average P-wave velocities, lower specific acoustic impedance, and higher open porosity and/or elastic anisotropy index compared to non-productive wells (Arkticheskaya-1, Admiralteyskaya-1, Krestovaya-1). This combination of petrophysical parameters provides the reservoir properties of rocks prospective for hydrocarbons. The petrographic variation of the reservoir properties of the studied rocks from productive to non-productive wells is associated with a decrease in grain size and a transition from pore-filling cement to thin-film and basal cement. The sandstones from the Shtokmanskaya well have a larger grain size (0.1-0.5 mm), whereas the sandstones from the Arkticheskaya-1 and Krestovaya-1 wells are finer-grained (0.1-0.2 mm). The Shtokmanskaya-1 well is characterized by pore-filling cement, the Arkticheskaya-1 ‒ by thin-film cement, and the Krestovaya-1 ‒ by cement of the basal type. The established physical properties of sedimentary rocks, suitable for the development of productive strata, will allow for the screening out of empty areas at the preliminary stage of analyzing geophysical materials during the search for geological and tectonic structures prospective for hydrocarbon accumulations.

Migmatized gneisses of the Chupa paragneiss Formation in the Belomorian Mobile Belt (BMB) of the Fennoscandian Shield have been studied, and the conditions of partial melting during high-grade metamorphism of the rocks were determined. The melting temperatures and pressures, the amount and composition of the melt formed during the anatexis of gneisses in a closed system, were assessed through direct thermodynamic computer modeling of mineral formation and the construction of pseudosections in pressure-temperature coordinates. The mineral formation calculations are based on the principle of Gibbs energy minimization and were performed using the PERPLE_X software package. The bulk compositions of the migmatized rocks from the Chupa Formation, previously classified and grouped based on their major components, were used for the calculations. It is shown that water-saturated partial melting of compositionally diverse gneisses produces granitic or granodiorite-tonalitic melts within a temperature range of 680-730 °C at moderate to moderately high pressures. The study reveals that the key factor controlling the appearance of kyanite in the investigated rocks is a high Al₂O₃/CaO ratio (at least 5:1) in the protolith, combined with a total alkali content (Na₂O + K₂O) exceeding CaO. According the Chemical Index of Alteration (CIA), the protoliths of the gneisses contained detrital material of varying sedimentary maturity. The source rocks were likely weakly to moderately weathered. U-Pb ID-TIMS dating of monazite from two samples of garnet-kyanite-biotite migmatite (whole-rock analysis) indicates Paleoproterozoic migmatization of the Chupa gneisses at 1854 ± 5 Ma. This phase of Paleoproterozoic endogenic activity is widely recorded in the BMB and may be associated with the formation of the Lapland-Kola or Svecofennian orogens, located to the northeast and southwest of the belt, respectively.

This study investigates unique weathering crust samples from the most altered sections (30-43 m) of the weathering profile within the Souktal Plutonic Complex, Northern Kazakhstan. The samples, obtained from two drill cores, consist of quartz, kaolinite, microcline, muscovite, and plagioclase, as identified through polarized light microscopy and confirmed by X-ray diffraction analysis. Sequential extraction of rare earth elements (REE) was performed using inductively coupled plasma mass spectrometry (ICP-MS) following a two-step leaching procedure with hydroxylamine hydrochloride (0.2 mol NH₂OH·HCl) and sodium hydroxide (1 mol NaOH) solutions. The extraction process effectively recovered REE, indicating their presence in an ion-exchangeable form, with total extraction rates (REE + Sc + Y) ranging from 4.1 to 7.8 ppm. The total light REE content varies from 3.5 to 5.9 ppm, while heavy REE content ranges from 0.2 to 0.7 ppm across all samples. Petrological and geochemical analyses suggest that the studied area represents an ion-adsorption-type REE weathered deposit. These findings enhance the understanding of ionic-adsorbed REE within weathering crusts and highlight the effectiveness of sequential extraction methods for REE determination. Moreover, the study suggests that this area holds promising potential as a future REE ion-adsorption site, contributing to the development of Kazakhstan’s national REE industry.

The issue of reducing electricity consumption costs is becoming relevant for industrial enterprises, taking into account the growing demand for electricity every year. The electricity consumption of air coolers at a gas processing plant was considered in the framework of this study. The change in ambient temperature (during the day and depending on the season) is the main disturbing factor affecting the performance of air coolers. With such significant seasonal changes in air temperature, its density changes, which causes fluctuations in the power consumed by the electric motor by up to 30 %. The issues of increasing energy efficiency, forecasting and determining the power consumption rate of air coolers, depending on changing external conditions, therefore become important. A methodology has been developed to determine the standard power consumption of air coolers depending on two factors – the ambient temperature and the load of the gas processing plant. A two-factor power-law approximation of the values was carried out due to nonlinear dependencies on plant loading and ambient temperature. The dependence of power consumption on ambient temperature and the loading of the installation on raw materials for any type of air cooler is determined with high accuracy (the root-mean-square error of the calculated and approximating values does not exceed 1 %). The formula for calculating the standard consumption of electric power of the air cooler at the considered installation was determined based on the results of the study. The methodology can be used by employees of gas processing enterprises to determine the standard electricity consumption of air coolers under changing climatic and technological factors.

The main stages within the chemically active history of diamond genesis are proposed, from the upper-mantle chambers to the explosive ejections of diamonds and kimberlite material from cumulative centers to the surface. The paper focuses on the pre-final episode of diamond deposit genesis – the interaction of diamonds with carbonate-silicate kimberlite magmas in a crustal cumulate chamber. Such interactions are possible when the transport of diamonds by these magmas from the depths of the mantle primary chambers to the surface is stopped within crustal rock complexes with a strong roof. The cooling and solidification time of kimberlite melts in such cumulative centers is long enough to cause a significant mass loss of dissolving diamonds. The interaction of carbonate-silicate kimberlite melts with varying carbonate content with natural single-crystal diamonds was studied experimentally at a pressure of 0.15 GPa and a temperature of 1200 °C. Model carbonate, carbonate-fluid, natural kimberlite, and kimberlite-fluid systems were used as solvents. At experimental conditions, the solvents melted, and diamond crystals surface were underwent by dissolution. It was established that etching patterns are recorded on the growth planes, and diamonds lose mass: from 3-4.5 % after 2-hour exposure (the order of kimberlite transport time from the upper-mantle diamond-forming centers to the crustal cumulative centers) to 47.6 % after 10-day exposure (at the crustal cumulative center conditions). The results demonstrate that the dissolving ability of carbonate-silicate transport magmas is a factor that effectively reduces the diamond potential of kimberlite deposits.

With the increasing complexity of electrical equipment in mining enterprises, the development and analysis of methods to enhance the reliability of technical devices within power supply systems are becoming increasingly relevant. This article focuses on assessing the reliability parameters of workshop network circuits in mining enterprises equipped with single-transformer substations operating at 10 and 0.4 kV, considering various redundancy methods. Research objective is to evaluate the reliability parameters of different redundancy methods for power supply circuits in facilities with transformer substations at medium voltage (MV) and low voltage (LV), with respect to low-voltage switchgear consumers in mining operations. Research target is the power supply system of an auxiliary production workshop at a mining enterprise (Kemerovo). The study examines the following network reliability parameters: probability of failure-free (normal) operation, P(t); probability of failure occurrence, Q(t); failure flow rate, ω_circuit; time between failures (TBF), Т_TBF. The analysis covers the following circuit configurations: without redundancy; with redundancy at MV; with redundancy at LV; with dual redundancy (at both MV and LV). Estimation results indicate that the TBF for the nonredundant circuit is 2.04 times lower than for the LV redundancy circuit, 2.11 times lower than for the MV redundant circuit, and 2.8 times lower than for the dual redundant circuit. Redundancy proves to be a technically and economically justified method for improving the P(t) parameter of the facility’s power supply system. The obtained results can be integrated into power supply system design (to optimize structural circuits and select rational redundancy methods for components), maintenance program development (to develop justified maintenance and repair schedules), reliability monitoring system development (to enable continuous monitoring of equipment status in mining enterprise workshops).

The amplitude of diurnal variations in atmospheric air temperature may exceed 25 °C depending on the climatic zone and season. This gives rise to unsteady heat-transfer processes in downcast mine shafts and in the subsequent underground workings along the airflow path. The present study focuses on investigating the damping effect of the amplitude of diurnal fluctuations in the thermodynamic parameters of atmospheric air in downcast shafts of potash mines. The thermal damping effect consists in the attenuation of air temperature fluctuation amplitude as the airflow moves down the shaft due to heat exchange with the shaft lining and mass-transfer processes. A combined theoretical and experimental approach is proposed to predict air microclimate parameters at the junction of a downcast shaft with an underground level using a conjugate convective-diffusive heat and mass transfer model that accounts for processes in the shaft air, the lining, and the surrounding rock mass. A methodology for conducting in situ measurements at the study sites is described, the necessary experimental and calculation parameters are provided, and field measurement data obtained for two downcast shafts of potash mines with different depths are presented. The experimental data were used to validate the proposed model. The agreement between measured and calculated results confirms the suitability of the selected model for predicting air temperature at the shaft-underground level junction. Effective heat-transfer coefficients between the airflow and the shaft wall were determined for both downcast shafts, along with effective thermal diffusivities of the surrounding rock mass. An empirical relationship was established for the air temperature in the shaft bottom chamber of the underground level as a function of the daily mean temperature, the amplitude of surface temperature fluctuations, and the shaft depth.

Study of fracture mechanics in heterogeneous rocks, including crack initiation and propagation, has practical applications for geocontrol and identification of fracture zones in hydrocarbon well extraction. The features of microcrack zone formation depending on the type of rock heterogeneity under triaxial stress state conditions are considered. The research was conducted using an MTS 815 servo-hydraulic testing frame integrated with a Milne DAQ acoustic emission system (Itasca International Company, UK). The paper presents the fracture results of samples of various lithological types manufactured from cores of post-magmatic rocks. Fine-grained samples with gneissic and banded textures, as well as a coarse-grained sample with massive texture, were tested. During the tests, acoustic emission (AE) was recorded using 12 piezoceramic sensors. To describe the geometry of the fracture zone, the coordinates of AE event hypocenters were calculated, then the configuration of hypocenters distribution was analyzed using a tomography procedure (layer-by-layer construction of AE event density maps), and the angles β between the direction of the macrocrack and the axial stress σ₁ were determined. To interpret the failure evolution, trends of the b-factor and AE activity were calculated, the intervals of critical behavior of which were correlated with the localization and tomography data. After testing the samples, the types of their deformation and the mechanism of destruction with the phenomenon of dilatation were revealed. It is established that for the considered types of sample inhomogeneities, various microcrack structures are formed under the same volumetric loading conditions. In fine-grained rock of gneissic texture, a linear distribution of AE hypocenters is formed, indicating the formation of microcracks along the direction of layering. For the fine-grained rock with banded texture, the hypocenter distribution is characterized by the formation of distinct clusters, reflecting areas of the most intensive fracturing. In the coarse-grained massive texture sample, a volumetric distribution of hypocenters is observed, manifesting dilatancy properties and the formation of an extensive microcrack network.

Limited data on the behavior of impurity elements during the formation of ore minerals in hydrothermal systems reduce their potential as indicators of the physicochemical conditions of ore formation. One of the most common sulfides capable of concentrating precious metals and other valuable components is pyrite. The distribution of a number of typomorphic impurity elements in pyrite under its crystallization in hydrothermal conditions at a temperature of 450 °C and a pressure of 1 kbar was studied. Using X-ray spectral microanalysis, scanning electron microscopy, and inductively coupled plasma and laser ablation mass spectrometry, data were obtained on the forms of occurrence, content ratios, and correlation relationships of impurity elements in the volume and surface layer of pyrite crystals. For the first time, the parameter S of surface phase selectivity with respect to main (Co, Cu, Ni) and minor impurities (noble metals, As, Zn, Mn) was determined, which averaged 1.9 (Co), 2.1 (Cu), 1.3 (Ni), 4.2 (Pd), 18.5 (Au), 6 (As), 10.2 (Zn), and 9.1 (Mn). The correlations between elements are significantly different for the surface and volume, which is explained by the influence of surface phase selectivity. The dual nature of the correlation between Au and As allows their relationship to be considered a surface phenomenon. Palladium, a critically important metal widely used in chemical catalysis and other areas of technology, exhibits unusual behavior in pyrite, concentrating mainly on its surface, which suggests the possibility of its concurrent extraction from pyrite ores at gold extraction enterprises. The observed correlations are considered from the perspective of the incorporation of impurity elements into the bulk structure of pyrite and into the compositions of surface phase-like formations (non-autonomous phases) that evolve during crystal growth and are enriched with incompatible elements.

The potential of hydroacoustic methods widely used in coastal engineering geophysical survey is limited in the presence of gas-saturated bottom sediments. Under unfavourable conditions it is advisable to use electric prospecting methods. This article analyses the efficiency of modern electric resistivity tomographic (ERT) technologies of the surface and seabed observation systems for studying the geological sections in coastal water areas. Basic geoelectric and electric resistivity tomographic models are synthesized to assess the influence of water salinity and lithological composition of sediments on the results of marine electric prospecting. Petrophysical modelling data showed that, along with the influence of pore water mineralization on the ratio of specific electric resistivity values ​​of dispersed soils, the mineral composition of clay minerals has a significant effect. This effect is manifested as a shift in the position of the inversion point of specific electric resistivity values ​​of sandy-clayey soils with increasing cation exchange capacity ​​​​typical of different mineralogical types of clays. Results of numerical modelling of electric resistivity tomography sections using surface and seabed observation systems demonstrated that the seabed measurement system provides reliable information on geoelectric structure of sandy-clayey sediment sections, while the sections obtained from the ERT survey on water surface exhibit distortions in the geoelectric section structure and false anomalies. The advantage of seabed ERT for studying the geological structure of coastal marine areas was ascertained. Experimental work in the Luga Bay water area in the Gulf of Finland confirmed the efficiency of the seabed ERT for increasing the reliability of cross-well geological interpolation when constructing composite geological and geophysical sections. The use of seabed ERT ensured a continuous tracking of geoelectric boundaries corresponding to different lithological species in seabed sandy-clayey sediments.

The article is devoted to the actively developing area of wastewater treatment – Constructed Floating Wetlands (CFW, floating bioplatforms). The paper explores the creation history and operational experience of CFW in Russia and abroad. It describes the designs and preferred compositions of substrates and plants for creating phytomodules, paying special attention to the use of natural minerals and the selection of local macrophyte plant species. The CFW technology is suitable for treating various types of wastewater, including inorganic effluents from mining enterprises. The research examines the results of applying phytotechnology for wastewater treatment for pollutants (total nitrogen and phosphorus, organic matter, suspended particles, heavy metals, sulphates, boron, etc.). The article shows successful practices of using CFW for acidic drainage effluents, which are the most challenging for phytotechnology application. The study identifies key factors affecting pollutant removal efficiency – water depth, flow rate, coverage area, aeration, and temperature. The research presents methods to enhance the depth of water treatment at low temperatures. It also notes the positive impact of floating bioplatforms on the condition of water bodies where they are located. The study provides cost estimates for applying CFW technology for wastewater treatment and gives recommendations based on the experience of implementing the technology at a settling pond of a mining enterprise in the Murmansk Region.