Home – Home – Jornals – Journal of Mining Sciences 2024 number 1

The article addresses current issues in the field of fiber-optic data transmission, related to the constant increase in demand for communication system bandwidth and nonlinear response. The main machine learning methods used to compensate for nonlinear signal distortions in long-haul coherent communication lines are presented, including neural networks of various architectures. The paper emphasizes the promising nature of machine learning-based solutions to enhance the performance of optical fiber communication systems, thanks to their ability to derive effective and adaptive signal recovery schemes with low computational complexity.

Lasers of various power classes from tens of µW to tens of W based on the stimulated Raman scattering (SRS) effect in waveguide elements made of tellurite glasses are studied. Due to the high SRS gain and large SRS frequency shift, tellurite glasses are promising materials for the development of laser sources at a wavelength of about 2.3 μm with a pump at a wavelength of about 2 μm, which was used in the work. A detailed numerical simulation of Raman lasers based on single-core and multicore special tellurite fibers is carried out. It is shown that the conversion efficiency of pump power to SRS wave power for optimal parameters can exceed 50%. Detailed modeling of low-power Raman lasers based on high-Q microresonators is performed; optimal parameters and factors limiting generation are found.

Resonance properties of the local field of metal fractal clusters are considered. The effects of surface-enhanced Raman scattering, photoluminescence enhancement, and nonlinear responses are studied. It is demonstrated that the model developed by S. G. Rautian, based on the quantum theory of nonlinearity, offers a more accurate description than previous theories. Among the scientific results of the theory proposed by Rautian and his team, the following points can be highlighted: metal nanoparticles with a diameter < 30 nm exhibit discrete energy levels, in contrast to semiconductor quantum dots; Rautian’s theory provides an accurate description of the linear part of the dielectric function, corresponding to the classical Drude model; the cubic nonlinear susceptibility according to Rautian’s model is consistent with experiments, indicating the contribution of conduction electrons.

The article provides a brief overview of modern achievements in quantum information science, problems and prospects for the development of quantum computing. The elementary mathematical model of quantum computing and the concept of quantum supremacy are discussed. The use of ultracold atoms for the implementation of quantum processors is considered.

The operation of our atmospheric quantum cryptography setup using the BB84 protocol and polarization coding has been investigated experimentally. The "sifted" quantum key distribution rate and the quantum bit error rate in the key remain constant for 1 hour and are equal to 7558±83 bit/s and 5.1±0.84%, respectively, at a distance of 20 m between the transmitter and receiver. The minimum possible transmittance of a quantum channel is calculated for these parameters of our setup.

The room-temperature visible photoluminescence of the In⁺ and As⁺ ion-implanted SiO₂ films is investigated as a function of As⁺ ion energy, annealing temperature, and excitation wavelength. As⁺ ions at the energy of 40, 80, or 135 keV and In⁺ ions at the energy of 50 keV, providing an average range ratio R_p^As/R_p^In of 1, 2 or 3, respectively, are used. The subsequent annealing is carried out at a temperature of 900 and 1100 °C. The photoluminescence spectra are excited with a laser wavelength l_ex = 442 and 473 nm. The photoluminescence peak near 550 nm is obtained at an excitation wavelength of 473 nm. The wavelength position of this peak is shifted to 520-530 nm at l_ex = 442 нм. As the R_p^As/R_p^In ratio increases, the photoluminescence intensity drops down, and the photoluminescence intensity ratio as a function of the annealing temperature is changed. The resultant effect is discussed in the frame of the electron and hole recombination within InAs nanocrystals.

The development of a multichannel application-specific integrated circuit (ASIC) for registration and processing of signals from microstrip sensors in synchrotron radiation coordinate detectors developed at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences to equip the experimental stations of the SKIF is presented. The ASIC contains 64 independent photon registration channels with four energy separation thresholds. The range of registered energies is from 3 to 60 keV. The structure and basic parameters of the electronics of the registration channel for direct photon counting are described in detail.

A comprehensive analysis of multispectral data obtained in different growing periods makes it possible to reconstruct the current state of the anthropogenically transformed natural environment and identify areas of historical nature management. Ambiguous displaying of secondary succession of forests requires comparison of changes in the spectral features of vegetation and features of the landscape objects texture in multi-season images. The methodological basis of such studies is an algorithm of multispectral data processing adapted to apply Haralick's textural features at the feature extraction stage. Joint segmentation of multi-seasonal multispectral images “smoothes out” local, less significant changes in the texture of landscape objects, which makes it possible to more clearly demonstrate the general trends in the distribution of vegetation. The area of interest included a fragment of the Pudemskiy ironworks dacha, where “timber and firewood forests” were cut down for the production needs in the 1st half of the 19th century. The segmented image demonstrates the fundamental differences between the vegetation cover of the western and eastern parts of the survey area: the site of historical cutting areas and the part that was not subjected to an intense anthropogenic impact.

The effect of multiplicative noise acting simultaneously with white noise on the accuracy of measuring the frequency of a coherent signal given as a sequence of coherent pulses is considered and analyzed. The condition for the absence of systematic errors at the output of the tracking meter is determined. The steepness of its discrimination characteristic, the spectral density of fluctuations at the discriminator output, and the coefficients that determine the normalizing action of automatic gain control are found. These values determine the amount of deterioration in the accuracy characteristics of the meter under the influence of multiplicative noise. It is shown that the influence of multiplicative noise increases with a decrease in the level of the undistorted part of the signal and with an increase in the ratio of the signal energy coherently accumulated in the linear circuits of the discriminator to the power spectral density of additive noise. It is shown that the effect of multiplicative noise is most pronounced in those cases where the width of the spectrum of the noise modulation function is commensurate with the bandwidth of the linear circuits of the discriminator.

The approach of applying machine learning methods for automatic detection of deer individuals in images is studied. The neural network technology is used to accurately count the number of deer from photographs. Deep learning methods for convolutional neural networks (Resnet50, DenseNet, CenterNet, InceptionV3, Xception) are used in conjunction with the “transfer learning” technique. Based on the Faster R-CNN Resnet50 network, a neural network is trained, which makes it possible to determine deer individuals from graphic images with an accuracy of 0.91 on a sample using the F1-score metric with a threshold value of 0.6.

The paper describes a technique for restoring images distorted by blurring from an unmanned aerial vehicle (UAV). Image reconstruction occurs using the point spread function (PSF), which is calculated based on a priori information about the basic flight and photographing parameters, as well as the physical properties of the optical system used. Well-known methods of image processing are used, such as restoration using the Wiener method, Lucy-Richardson method, Tikhonov method, and blind deconvolution method.

The paper deals with a new method of resolution enhancement in optical microscopy by the method of spatial subpixel shifts, i.e., shifts by some value smaller than the resolution provided by the objective lens. The resolution of optical microscopes is determined by the type of objective lens used. Professional microscopes have a set of microlenses with different magnifications, which are mounted on a turret containing several lenses. It is shown that a single objective lens can be used instead of a set of microlenses if subpixel shifts can be provided. An increase in spatial resolution is provided using the subpixel shift technique. In this case, the spectrum of the feature is augmented by a multiplier, whose type depends on the type of the lens aperture. To obtain high-resolution features, it is necessary to divide the Fourier spectrum of an image formed from several subpixel shifted images by a multiplier depending on the aperture type. This multiplier is called the aperture function. The aperture function is determined by the type of the lens used and can be its passport value. The paper illustrates an experimental method of obtaining the aperture function of a low-resolution (8×) lens calibration based on images obtained with high-resolution (40×) lenses. After determining the aperture function, one low-resolution lens can be used to acquire images with a resolution smaller than that of the selected high-resolution (40×) lens.

The accuracy of the construction of "depth maps" of space using an active-pulse television measurement system is evaluated on the basis of experimental data. Two multi-area methods of constructing "depth maps" are described. Results of estimation of the absolute and root-mean-square errors of range measurements for "depth maps" constructed from real and averaged frames obtained by the multi-area methods mentioned above in experimental studies are presented. The approximating functions of linear and polynomial types calculated by the least squares technique are taken as measuring functions used to construct the depth maps.

The authors analyze weak seismic activity at the Korobkovo iron ore deposit in the area of the Kursk Magnetic Anomaly. A sensing system in use enabled recording seismic events with a magnitude from - 2.5 to - 1.4 induced by a large-scale blast. Localization of hypocenteres was accurate to ~ 50 m. The most of sources of the recorded events occurred in the neighborhood of a faulting zone across the zone of mining, and at the interface of bed series. The values of a seismic moment of the events are within of two orders of magnitude 10⁵-10⁷ N∙m at an angular source frequency of 70-600 Hz. The estimated seismic energy ranges from 0.0006 to 1 J. The reduced seismic energy values from 2∙10^-9 to 2∙10^-7 J/(N∙m) and the low velocities allow categorizing the recorded events as slow earthquakes.

The spotlight of the analysis is on the elastic properties of dolomite and limestone host rocks of diamonds at the Botuoba Pipe in the conditions of partial saturation. Pre-saturated rock samples were subjected to three testing cycles during natural drying in room conditions. The change patterns in the elastic modulus of the test rock materials are determined subject to their water contents in different regimes of water saturation. The authors arrive to the conclusion that the prevailing concept of water effects on the mechanical properties of rocks is only valid in the steady-state conditions and is invalid in the unsteady-state conditions when moisture is nonuniformly distributed in the pore space of rocks.

The article describes the laboratory testing of permeability and structure of loose rock hardened with two-component highly elastic polyurethane resin at different methods of impregnation and at different consumptions of the polymer. Two methods of impregnation are tested: with a single solution as a mixture of two resin components and with a double solution of separate components mixed inside the test rock. It is shown that the decrease in the volume of resin from 20-40 to 5-10 vol% results in abundance of inter-grain voids and through permeable pore channels, and in an increase in the rock permeability by two-three orders of magnitude. The single-solution impregnation with the ready mixture ensures lower permeability of the test samples.

The propagation of elastic vibrations in rock samples in compression and under impacts to failure is investigated experimentally. Under impacts, a signal of acceleration was recorded in the samples, and the spectral density was calculated to determine velocities of elastic vibrations. It is found that under increasing load up to a pre-failure value, the P- and S-wave velocities grow, and the S-wave velocity increases by more than 50%. The acoustic Q-factor rises by 70%. The energy of the microseismic emission under pre-failure loads is two times higher than under low loads, and the high-amplitude spectral components generated under pre-failure loading are reflective of large discontinuities being formed.

The article discusses an integrated approach to finding causes of pit wall failure in Zhelezny Mine of Kovdor GOK. Radar monitoring with IBIS provided data for the slope instability prediction. The stability calculation is performed and analyzed for the failed site of the pit wall. It is shown at the adopted strength properties, failure of the upper bench is only possible as its stability factor is less than 1.50. The causes of instability could be the decreased strength of the pit wall as a result of weathering or watering, and failure could occur along a fracture. An industrial building in the close vicinity of the failure site had no influence on the slope stability. The recommendations on finding certain causes of instability are given.

The article describes the lab-scale tests of hydraulic fracturing in the nonuniform stress field. Fractures were created in a system of two and three cross holes made in artificial cubic blocks with the edges 420 mm long. The stress raiser generated at the intersection of the holes facilitates fracturing in the neighborhood. In the tests the maximum compression was applied to a sample in perpendicular to the plane containing the axes of the holes. It is found that in such stress field, the system of three holes stabilizes a fracture in the mentioned plane better than the system of two holes.

The mine shafts in the salt (unwatered) rock mass at the Upper Kama deposit are mostly lined with cast-in-place concrete and reinforced concrete, which should ensure the required load-bearing capacity and water impermeability in host rocks in creep. The long-term observations of the shaft lining in operation revealed some typical patterns of failure induced by the rheological properties of salt rock mass under the action of rock pressure. The technical evaluation of the lining and reinforcement of mine shafts is an integrated checkup procedure including measurements of fractures and areas of corrosive zones/rock falls; updating of actual geometrics of lining from laser measurements; determination of residual strength of lining; mathematical modeling; estimation of integral reliability index of lining. The authors propose a procedure to categorize technical conditions of concrete lining in mine shafts in operation in salt-bearing rock mass in creep. The application of the procedure is described, and the conclusions on the package of repair activities are drawn.

The article describes two single-mass models of a drill string and different methods of bottom-hole treatment: percussion and rotary percussion. The loads created by the piston are transferred to rocks via a progressively advancing bit in the first model and via a rotatable bit in the second model. The drag force applied to the bit is found from the nonlinear dependence on the penetration rate and kinematic parameters which govern the force impact on the rock and its loss of strength: initial blow velocity and rotational speed modulus of the bit. The optimal initial blow velocities are found at the preset blow frequency; they ensure elimination of short-term stick slips in penetration of the bit. For the mentioned cases of penetration, the processes of percussion and rotary percussion drilling in strong rocks are provided with the strict mathematical description. The numerical modeling results are presented.

This study discusses the dependence of blast fragmentation size on field parameters and rock properties. For this purpose, six limestone quarries of productive cement factories of Pakistan were selected, including a total of 19 working bench faces. The field work included determination of rock fragmentation size, field penetration rate, rock mass parameters and blast design parameters. The geo-mechanical laboratory testing program includes LCPC rock abrasivity tests, NTNU/SINTEF drillability tests along with determination of laboratory drilling rate index and physico-mechanical rock property tests. The technique of least square regression was adopted to explain the obtained dependence. Finally, three multiple regression models were proposed for the estimation of rock fragmentation size from the test field and laboratory scale parameters. The quality of developed multi-variable models was statistically validated through statistical performance indicators.

In this study, the rock drillability tests, as well as a comprehensive set of physical and mechanical rock property tests were performed on rock units selected from various localities of Pakistan. Petrography of included rock samples was also conducted for the computation of geotechnical wear indices including Schimazek’s F-value, rock abrasivity index and the Vickers hardness number for rocks. Initially, univariate regression analysis was performed to check the dependence of drillability parameters on physico-mechanical properties and rock wear indices. Significant correlations of drillability parameters with uniaxial compressive strength were found. Similarly, Sievers’ J-value and drilling rate index showed considerable dependence on Schimazek’s F-value. In the next step, multivariate linear regression models of Sievers’ J-value, brittleness value and drilling rate index, based on physical, mechanical and petrographical rock parameters were developed. Finally, the predictability of proposed multiple regression models was validated by employing the statistical performance indices.

The effect of variations in the composition of kaolin and basalt on the geopolymer characteristics was carried out. The drying time was 4 h for cubic samples at 40, 50 and 60 oC and 9 h for cylindrical samples at 70 and 90 oC. The best geopolymer was K4 cylinder at 90 oC, which had a compressive strength of 8.075 MPa. The density of K2 cube geopolymer ranged as 26-1.94 g/cm³ at 60 oC. Silica-alumina compounds dominated the constituent compounds of geopolymer concrete, and the phases formed were quartz, anorthite and muscovite.

The ordinary Portland cement (OPC) as usual binder is widely used for the backfilling in the Zijinshan Copper mine of Fujian province, whereas it leads to high cost of cemented paste backfill (CPB) every year. The main objectives of this study were to investigate the effect of low-calcium fly ash (LCFA) substituting for OPC on the compressive strength of CPB samples, through treating LCFA with mechanical and chemical action method to improve its pozzolanic activity. The experiment results show that the compressive strength of CPB samples is not increased when the non-treated LCFA is added into substitute for partial OPC. However, the compressive strength is obviously improved by the replacement of partial OPC with treated LCFA. When the substitution ratio of treated LCFA is 29.8%, the 28-day compressive strength of CPB samples with binder/tailing ratio of 1:6 achieves 3.9 MPa, and is 1.95 times higher than that of CPB samples with OPC as sole binder under the same condition. The economic analysis result exhibits a partial replacement (29.8%) of OPC with treated LCFA can save 28.7% of cemented backfill cost, indicating great economic benefit for underground backfilling mining.

The optimization problem is formulated for the cross-section outline of bulkload on a belt conveyor and for the kinematic parameters of the latter. The analytical solution on the optimum angle of side rollers and cross-section outline of bulkload on the belt is presented. The influence of the friction angle on the optimum cross-section outline of bulkload on the belt is illustrated. The optimization of velocity and acceleration of belt conveyor in the start period is described. The influence of the angle of the side rollers on the rolling friction is determined.

The article offers the force and geometry analysis of the stone block-diamond wire saw system. The friction force of the diamond wire saw in the block is determined at the parabolic adjustment of the wire sawing trajectory. The curves of the sawing force and horizontal coordinates of the blocks are plotted at different values of the parabola focus point. The actual sawing trajectories in monoliths and blocks are described. The load increase factor at the beginning of work is obtained. Using the procedure of the actual sawing trajectory, the strength analysis of the diamond segments of the diamond wire sawing machine is performed, and the stress diagrams in the diamond segments with a sharp and rounded edge are constructed. The maximal stresses in the diamond segment with the rounded edge are plotted as function of the rounding radius.

The authors discuss dynamics of gas bubble and mineral particle in low-viscous fluid. The particle-bubble interaction model represents a system of associated differential algebraic equations. Dynamics of the disturbed system is described using the Lagrangian method. The model takes into account oscillations of bubble surface and attached solid cylindrical particle in the infinitive volume of perfect incompressible liquid. The capillary force retaining the particle on the bubble is governed by the meniscus shape which conditions the wetting angle. The Legendre series expansion is used to represent small axially symmetrical oscillations of the particle-bubble system. The potential and kinetic energies of the system are expressed in terms of the coefficient of this series. The resultant eddy-free velocity field allows including the viscosity effect with regard to the local rates of energy dissipation.

Chemical modification of phenyl-formaldehyde oligomers (PFO) was carried out, and compositions based on elastomer, co-oligomer and bitumen were developed in order to achieve significant improvement of characteristics and expand the areas of PFO application. The phenol-formaldehyde oligomer was modified with carbamide by co-polycondensation in an alkaline medium. The basic physicochemical, physical-mechanical and performance characteristics of the co-oligomer were studied. The co-oligomer of the new composition, obtained at the first stage of the investigation, was used as a binder. At the second stage of investigation, a three-component composition was developed on the basis of elastomer, co-oligomer and bitumen, and a composite material was prepared. This material was shown to exhibit good protective properties, and it may be recommended to provide anti-corrosive protection of the equipment and installations in oil and gas mining industry. The effect of the amounts of introduced components on the major characteristics of the resulting composition was studied. It is shown that the introduction of a nitrogen-containing modifier (carbamide) into PFO causes a decrease in the content of free phenol and formaldehyde, which is important both from the environmental viewpoint and in relation to the hazardous action of these components on the human organism.

The kinetics and mechanism of hydrogen evolution on the MoSi₂ electrode in x M H₂SO₄ + (0.5-x ) M Na₂SO₄ ( x = 0.50; 0.35; 0.20) solutions have been studied. The cathodic polarization curves of MoSi₂ in the studied solutions are characterized by Tafel region with a slope of (-0.070)±0.002 V. The reaction order of the cathodic process with respect to hydrogen ions at the potentials of Tafel region is ~1.0; the derivative of the electrode potential with a change in electrolyte acidity is ~0.072 V. The impedance spectra of the MoSi₂ electrode in the studied potential range have the shape of a semicircle located in the capacitive half-plane, with the centre in the region of positive values of the imaginary impedance component; in the region of the highest frequencies, a short straight section is recorded on the impedance plots, indicating the presence of pores in the surface layer of the electrode. To describe the hydrogen evolution reaction on MoSi₂, we used an equivalent electrical circuit, the Faraday impedance of which consists of series-connected charge transfer resistance ( R₁) and a parallel R₂C₂Z_d-chain responsible for the adsorption of atomic hydrogen on the surface and its diffusion into the depth of the electrode material. The equivalent circuit also includes the solution resistance (R_s) and the double layer capacitance impedance, which is modeled by the constant phase element CPE₁. It is shown that the hydrogen evolution reaction on molybdenum disilicide in a sulphuric acid electrolyte proceeds along the discharge - recombination route with a quasi-equilibrium discharge stage when the Temkin logarithmic isotherm for adsorbed atomic hydrogen is fulfilled. The hydrogen evolution reaction is complicated by hydrogen absorption proceeding in the mode of solid-phase diffusion kinetics.

Physicochemical foundations for the technology of nitrogen acid processing of serpentinite from the Karakalpak deposit with the formation of pure magnesium nitrate and magnesium-containing compound fertiliser are developed. The chemical and mineralogical composition of serpentinite from the Karakalpak deposit is studied. As determined by X-ray diffraction analysis, microscopic and thermogravimetric studies, serpentinite sample contains clinoenstatite, pyrope, spinel, magnetites and other minerals with various crystal structures. Data on the extraction of serpentinite components in nitric acid by decomposition under different conditions (temperature, duration, nitric acid concentration) are presented. The subsequent stages of nitric acid extract processing have been carried out: removal of silica residue, ammonisation of the filtrate in order to precipitate undesirable impurities to obtain magnesium nitrate. The process of evaporation and crystallization of the filtrate to obtain pure magnesium nitrate has been studied.

The content of the main groups of biologically active substances in the flowers, leaves, rhizomes of Iris setosa cultivated under the conditions of the forest-steppe zone of the Novosibirsk Region has been determined. The content of tannins, pectins, protopectins, catechins, flavonoids, carotenoids during the seasonal development of plants was determined. It is found that tannin content in the leaves in all phenophases of I. setosa plant development is 6.3-8.5 times higher than in rhizomes. During the flowering period, flavonoid content in the leaves is 29.7 times higher than in rhizomes, during the stage of blossom fading it is 18.1 times higher, and at the stage of fruiting it is 25.1 times higher. The same accumulation of catechins (0.23-0.24 wt%) was found in underground and aboveground organs during the period of blossom fading. Pectin content in leaves during fruiting was detected to be 2.4-2.7 times higher than during flowering and blossom fading. Pectin content in rhizomes is 2.2-2.4 times higher during blossom fading and fruiting than during flowering. The content of carotenoids in flowers during flowering is 2 times higher than in rhizomes, but 2.6 times lower than in leaves. It is noted that the quantitative content of biologically active substances in the organs of I. setosa is determined by the peculiarities of growth and development during the seasonal period.

Pilot-scale tests results and laboratory studies of fire-resistant hydraulic fluid based on the developed hydraulic concentrate Hydrotol-ITCh HFAE are presented. Stable operation and operating parameters preservation of the developed hydraulic fluid physicochemical properties under the real conditions on a contaminated hydraulic system of a mining industry enterprise are shown. It was found that during six months of operation, the range of pH values, electrical conductivity, concentration and bacteriological purity did not change significantly, while the concentrate refilling, as well as the use of special disinfectants and cleansers, was not required. For the first time, the microbial composition of hydraulic fluid exposed to operation in the powered supports of the enterprise was studied using the method of metagenomic sequencing. Molecular genetic methods revealed a wide range of bacterial associates with various types of metabolism, including anaerobic sulphate-reducing bacteria involved in the biological corrosion of metals.

In 1957-1959, according to the program of the 3rd International Geophysical Year, the temperature of rocks (to a depth of 20 m) and glacier ice (to a depth of 45 m) was measured in the area of a high-mountain weather station (glacier no. 31) in the central part of the Suntar-Khayata Ridge (Northeastern Russia). In 2012-2017, the Russian-Japanese expedition carried out new measurements of the temperature of rocks and glacier ice at the same places. A comparison of the data on the mean monthly temperatures of glacier ice at a depth of 10 m in 1958 and 2012 attests to their rise by 1.0-1.6 °С. As there was no possibility to perform direct measurements of rock temperature at a depth of 20 m in 2012 -2017, we used an indirect method to estimate it at the depth of zero annual amplitude. According to our estimate, in the past 60 years, it could have increased by up to 1.6 ° C. Regime studies of the dynamics of seasonal thawing were carried out at four experimental plots; of the dynamics of freezing of the seasonally thawed layer, at one plot .

Results of the study of the regularities of new formation of frozen ground near the southern boundary of permafrost against the background of a positive climate trend are presented. Criteria for the potential formation of permafrost in response to climate warming are established. Results of modeling and quantitative assessment of the newly formed permafrost caused by transformation of landforms during thawing of frozen ground are given with respect to soil drainage and warming effect of the snow cover.

The results of sedimentological analysis of bottom sediments of the Ivashkina Lagoon on the southern coast of Bykovsky Peninsula (southeast of the Laptev Sea) are presented. Core samples from boreholes drilled in the Holocene thermokarst depression now occupied by the lagoon have been analyzed. The use of grain-size distribution data and Passega C-Md diagrams makes it possible to refine the genetic interpretation of the sediments obtained from field descriptions. The Holocene lacustrine-lagoon and taberal formations and the underlying Middle and Late Pleistocene alluvial sediments have been identified, and their grain-size characteristics have been determined. We have further reconstructed the sequence of their formation while a thermokarst depression had been transformed into a lagoon.

The morphology and properties of frozen strata were studied in the area of the largest retrogressive thermal thaw slump Batagay (Yakutia). A presumably continuous stratigraphic sequence of permafrost sediments accumulated during the Middle and Late Pleistocene (~700-11 ka) and was partially transformed during the Holocene. Based on paleopedological, paleontological, and geocryological data, new suggestions have been made regarding the historical development of the soil-vegetation cover and late glacial fauna in the Yana Plateau region. Two extensive and relatively warm climatic periods favoring the formation of developed soil-vegetation cover have been identified: the first one belongs to MIS 15-17 (600-700 ka) or (depending on the dating method) to MIS 7e (230-250 ka); the second one is more certainly dates back to MIS 5e (110-130 ka).

The paper presents the results of studying the appearance and sizes of pockmarks in lakes of three bioclimatic zones of Yamal: northern (arctic), typical, and southern tundra. The diameter of pockmarks in the lakes increases from 1.9 m in the northern tundra to 7.7 m in the southern shrub tundra. Pockmarks occupy from 0.5 to 4.3 % of the shallow-water lake area. The content of methane in lake sediments is two or more times higher than in the sediments of the active and transition layers of dominant landscapes. In the typical tundra zone, the methane content in lake sediments is usually about 7 mL/kg, but in some cases it can reach 18 mL/kg and more. Probably, these are the lakes with the high methane content in bottom sediments, where gas emissions can occur and pockmarks can form. After drainage (drying) of the lakes, lake basins (khasyreys) are subjected to freezing, and the cryogenic structure of lake sediments is formed. Eight-ten years after drying, succession changes in the former lake bottoms continue, and the formation of the transition layer is not yet completed.

The results of modeling the consequences of a hypothetical outburst flood from Lake Dasht (Tajikistan, the Shakhdara River basin) with the use of FLO-2D and FLOVI mathematical models are presented. The discharges of the outburst flood and debris flow and the increment of solid material in the debris flow have been obtained using the FLOVI program. The debris flow movement and accumulation in the valley have been simulated using the FLO-2D hydrodynamic model. The results indicate that the application of data obtained from the FLOVI program with transport-shift equation block in the FLO-2D model gives more correct characteristics of the debris flow, including the values of flow discharge, velocity, depth, and flooding area.

On November 10, 2023, Stanislav Ivanovich Zabolotnik, leading researcher at the Laboratory of General Geocryology of the Melnikov Permafrost Institute, Candidate of Geological and Mineralogical Sciences, Member of the International Academy of Informatization passed away at the age of 86 after a serious long illness. Stanislav Zabolotnik will be remembered as a remarkable permafrost researcher, an experienced field worker, and science manager.