Home – Home – Jornals – Journal of Mining Sciences 2022 number 1

We present materials of aerial photography of Cape Rytyi, a unique and most mysterious place on the northwestern shore of Lake Baikal. Photogrammetric survey was carried out using a DJI Phantom 4 Pro V2.0 UAV and provided an orthophoto and a digital terrain model of an 11.074 km² area. When deciphering the images obtained in the Rita River deltaic sediments composing the cape, surface ruptures trending north and northeast at 30-150 m from the shore of Lake Baikal were discovered. The ruptures are a clearly localized zone 2.9 km in total length. The performed analysis showed that the structural features of the zone obey the general laws of the development of faults resulted from prevailing extension. It has been established that the formation of the ruptures was predetermined by tectonics and is a secondary effect of resonant oscillations from the M = 5.2 earthquake of 08.13.1962, the epicenter of which was located ~35 km southeast of Cape Rytyi, in the Morskoi fault zone. The seismic event initiated the formation of surface ruptures, which led to a gravitational subsidence of coarse deposits of the fan in the shore zone. It is concluded that the development of modern geomorphologic forms in the peripheral part of the Rita River fan on land is similar to the formation of an underwater topography in the region of the Selenga River delta. It occurs under the influence of seismogenic rupturing and following gravitational movements, which intensify in a water-saturated environment and are subsequently complicated by erosion processes.

The paper presents a synthesis of zircon U-Pb and Lu-Hf and whole-rock Sm-Nd isotope data from main early Precambrian (3.4 to 1.85 Ga) metamorphic and magmatic units of the Irkut block (Sharyzhalgai uplift, southwestern Siberian craton). The Archean complexes consist of relict Paleoarchean (3.4 Ga) melanocratic granulites and predominant Neoarchean mafic and felsic granulites (2.7-2.66 Ga), paragneisses (≤2.75 Ga), and gneissic granites (2.54 Ga). The Paleoproterozoic complexes include paragneisses (1.95-1.85 Ga), granitoids and charnockites (1.86-1.84 Ga), as well as mafic intrusions and dikes (1.86 Ga). Few detrital zircons with Hf model ages of ≥3.6 Ga mark the Eoarchean onset of crustal growth in the Irkut block. Isotopic data record two major stages of crustal growth in early Precambrian evolution of the Irkut block: Paleoarchean (3.6-3.4 Ga) and Neoarchean (~2.7-2.66 Ga). The Paleoarchean crustal growth was most likely associated with plume magmatism fed from depleted and primitive mantle sources. The spatial distribution of Paleoarchean crust is traceable in isotopic signatures of magmatic and detrital zircons from most of Mesoarchean to Paleoproterozoic units. The Neoarchean crustal growth from a depleted mantle source was due to subduction magmatism. Moderate crustal growth occurred in the Paleoproterozoic from 2.3 to 1.85 Ga. At the turn of 1.86-1.85 Ga, mafic magmas and products of their fractionation formed from both depleted and enriched sources under postcollisional extension; the latter sources were the subcontinental lithospheric mantle formed during Neoarchean subduction. Three major stages of crustal recycling have been established: Mesoarchean (~3.0 Ga), Neoarchean (~2.55 Ga), and Paleoproterozoic (1.86-1.85 Ga), which are characterized by near-coeval intracrustal melting and metamorphism. The recycling during the ~2.55 Ga and 1.86-1.85 Ga events apparently occurred in a collisional setting. The 2.7 Ga subduction-related felsic magmas also formed through the recycling of the Paleo-Mesoarchean crust. The hypothesized scenario for the geological evolution of the Irkut block is the dominant vertical growth and crustal recycling for about two billion years. Available isotope data record similar major crustal growth in the Paleoarchean and growth combined with recycling during the Neoarchean and Paleoproterozoic events in both the southwestern and northern and central parts of the Siberian craton. The Irkut block in the southwest differed in a long and continuous recycling during the Mesoarchean and pronounced Neoarchean crustal growth.

To reveal the formation conditions of synnyrites in the Synnyr alkaline pluton, we studied melt inclusions in the minerals of shonkinites and pseudoleucite syenites, in apatite segregations in pyroxenites, shonkinites, and synnyrites, and in the minerals of later monchiquite-camptonite dikes. Based on the obtained and earlier published data, a conclusion has been drawn that all plutonic rocks of the massif formed from the same parental alkali-basaltic magma during long-term crystallization differentiation and fractionation in a closed system excluding a release of volatile components. Similar minerals in the rocks crystallized at similar temperatures in the same sequence: clinopyroxene (1280-1150 °С) → leucite (1250-1200 °С) → K-feldspar (1200-1180 °С) ↔ apatite (above 1180-1050 °С) → nepheline and kalsilite. The composition of the parental magma during crystallization evolved toward an increase in Si, Al, and K contents and a decrease in Fe, Mg, and Ca contents, i.e., toward melaphonolite and phonolite melts. The differentiation and fractionation processes led to the separation of minerals according to their specific gravity: Heavy minerals (clinopyroxene, ore minerals, and apatite) descended to the bottom of the magma chamber, forming the lower melanocratic series, and light minerals (leucite, K-feldspar, and foids), together with the residual melt, accumulated in the upper horizons of the chamber, forming the upper leucocratic series of rocks. During crystallization, the amount of fluids increased. At 920-830 °С, the fluids contained 3033-4051 mg/kg СО₂, 397-644 mg/kg Н₂О, and 42.7-83.7 mg/kg СО. At the early high-temperature stage, when the amount of fluids was insignificant, the trend of magma transformation coincided with the trend of basaltoid crystallization. This fact is evidenced by the homogenization temperatures and chemical composition of inclusions in the minerals of monchiquite-camptonites and alkali basaltoids, similar to those in the plutonic rocks of the massif. Clinopyroxene crystallized in dike rocks at 4.58 kbar at a depth of 10-12 km. At the stage of crystallization of feldspars, when the amount of fluids in melts significantly increased during the formation of plutonic rocks and drastically decreased during the formation of basaltoids, the formation trends of these rocks became different. The trend of basaltoid crystallization was directed toward trachyte melts with an increase in Si contents and a decrease in Fe, Mg, Al, and alkali contents. During the formation of plutonic rocks of the massif, the high water pressure prevented the formation of plagioclase, and the melts became more enriched in Al and K and acquired a high-alumina ultrapotassiс composition, forming kalsilite-nepheline-K-feldspar synnyrites at the final stages of transformation. A conclusion has been drawn that synnyrites crystallized from the residual products of differentiation and fractionation of alkali-basaltic magma in the temperature range slightly above 1050-1180 °С in a closed system excluding a release of volatiles. The occasional occurrence of synnyrites is due to the limited natural occurrence of closed magma chambers, macroanalogs of inclusions of mineral-forming media in minerals.

Results of a geochemical study of brines and oil occurrences in the Udachnaya kimberlite pipe are presented. Like other intrusions in the Daldyn-Alakit diamondiferous region, this diamond deposit is a unique cryohydrogeologic microstructure differing from the host sedimentary rocks and other diamond pipes of the Yakutian diamond-bearing province. Two waterlogged zones distinguished in the section of orebodies at the explored depths of the deposit correspond to the upper and middle Cambrian aquifers. Predominantly acidic (average pH = 5.5) Cl-Ca and Cl-Ca-Na brines with TDS from 94.3 to 391.3 g/dm³ are widespread within the orebodies and host rocks. The brine mineralization and contents of major salt-forming components increase with depth, to the horizon at the -365 m elevation, where TDS reaches 391 g/dm³, while below, at the -650 m level with noted hydrogeochemical-field inversion, TDS is 253 g/dm³. The mineralization of Cl-Ca, Cl-Ca-Na, Cl-Ca-Mg, and Cl-Ca-Mg-Na brines in the upper Cambrian rocks varies from 102.9 to 192.9 g/dm³, and the pH values, from 4.9 to 6.2, averaging 5.6. Among the microcomponents, the highest average concentrations (mg/dm³) are found for Br_1292.8 > S_875.7 > Sr_453.7 > Fe_79.7 > Li_53.4 > B_32.7 > I_13.3 > Si_10.8 > Mn_6.4 > Se_3.6 > Rb_2.3. The values of genetic coefficients vary widely: The r Na/ r Cl coefficient ranges from 0.18 to 0.31; r Ca/ r Mg, from 1.03 to 3.60; Ca/Cl, from 0.2 to 0.3; and the integrated metamorphism index S (according to S.L. Shvartsev) varies from 193 to 277. The middle Cambrian rock complex, containing more saline brines, has been examined in much more detail. It hosts Cl-Ca, Cl-Ca-Na, Cl-Ca-Mg, and Cl-Na-Mg brines with TDS from 94.3 to 391.3 g/dm³ and high average concentrations (mg/dm³) of microcomponents: Br_2224.9 > Sr_1024.9 >S_500.1 > B_202.9 > Li_147.1 > Fe_97.0 > I_33.2 > Rb_11.4 > Si_9.6 > Se_9.5 > Mn_3.6 > Ni_1.7. As compared with brines in the overlying rocks, the middle Cambrian brines show a wider variation in element ratios: r Na/ r Cl from 0.14 to 0.34, r Ca/ r Mg from 0.66 to 9.71, and Ca/Cl from 0.03 to 0.45. These brines are also characterized by a significantly higher metamorphism grade, which is indicated not only by the r Na/ r Cl and r Ca/ r Mg ratios but also by the S index varying from 278 to 316. The composition of stable isotopes (δD and δ¹⁸O) and dissolved inorganic carbon (δ¹³C) of the brines was investigated. The studied waters are assumed to be of sedimentary-metamorphic origin. Their isotopic composition reflects the climatic conditions existing at the time of their burial, which were probably aggravated by the contribution of the oxygen isotope exchange with water-bearing rocks. The δ¹³C values of carbon dioxide dissolved in water allow an inference about its biogenic origin. The biogenic carbon isotope exchange is governed by the relationship between methanogenic and SMT processes. Analysis of the ⁸⁷Rb/⁸⁶Sr and ⁸⁷Sr/⁸⁶Sr isotope ratios of the studied brines has revealed affinity between the isotopic compositions of waters in the Cambrian deposits and in ancient seawaters. The mass chromatograms of saturated-hydrocarbon (HC) fractions show at least two individual types of oils and malthas (naphthides). The third variety resulted from their mixing at different stages of migration. The fourth is from the contact zone; it changed during the explosion of kimberlites. The first, most common, type of naphthides («postexplosive») is similar in all geochemical parameters to oils from the Nepa-Botuobiya anteclise, in particular, to those from the Mirnyi arch. Oils of the second (pre-explosive) type are found only in the Udachnaya Formation, within the depth range 1130-1430 m.

The isotope-geochronological studies of ore metasomatites from the Unglichikan gold deposit have shown their age of 136-140 Ma. There are no data on magmatism of this age within the study area; therefore, it is impossible to associate the ore mineralization of the Unglichikan deposit with magmatic processes. The thermal event superposed on the host rocks of the Zlatoustovsk Formation beyond the ore zone is dated at 140 ± 2 Ma. Thus, the last stage of regional metamorphism and deformation and the formation of ore metasomatitesare are of the same age. We believe that the orogen deformation processes accompanied by hydrothermal activity played a significant role in the mobilization and redistribution of ore matter and in the formation of the Unglichikan deposit.

Here we report the first data on the absolute intensity value of the geomagnetic field on the Permian-Triassic boundary from basalts of the Kuznetsk basin. The latter are considered as one of the manifestations of the initial stage of trap magmatism during the formation of the Siberian large igneous province. The good preservation of information on the ancient geomagnetic field in the Mal’tsevskaya Formation basalts is due to the presence of small single domain and pseudo-single domain grains of primary magmatic titanomagnetite in the groundmass. The paleointensity values obtained following the Thellier-Coe method correspond to the generally accepted criteria of reliability and indicate that the geomagnetic field intensity during the formation of the Kuznetsk basin traps on the Permian-Triassic boundary was almost an order of magnitude lower than the present-day one. Moreover, the mean values of the virtual dipole moment for the Kozhukhta and the Vlasov units in the lower and middle Mal’tsevskaya Formation ((1.9 ± 0.6) × 10²² A × m² and (1.1 ± 0.7) × 10²² A × m², respectively) are in good alignment with determinations of the paleointensity during the accumulation of the Ivakinsky Formation of the Norilsk Region in the Siberian province, which confirms the accuracy of traditional regional correlations.

To obtain realistic and correct estimates of strong ground motion in the area of construction of the second Severomuisk tunnel, the records of local earthquakes obtained by the Severomuisk seismic station (SVKR) in 2005-2010 are studied (magnitudes M_b of ~4.2-5.5, hypocentral distances r of ~15-220 km). Stochastic-simulation methods are used to estimate the regional parameters of radiation and propagation of seismic waves in northeastern Buryatia: the stress parameter Ds, shapes of source spectra, wave attenuation at high frequencies (k), parameters defining the shape and duration of the acceleration time history, etc. Beforehand, the duration of strong motion as a function of the hypocentral distance was evaluated from the records; the local site amplification A ( f ) was estimated based on the velocity structure of the region; and the envelope method was applied to estimate the quality function Q ( f ). The following data were obtained: Ds ≈ 100 bars; k ≈ 0.012 s; Q ( f ) as ~ 60 f ^1.05 for r of ~15-30 km, ~ 80 f ^1.0 for r of ~40-60 km, ~ 90 f ^0.9 for r of ~100-110 km, and ~ 150 f ^0.7 for r of ~160-220 km; geometric spreading as 1/ r for r < 50 km, 1/50 for 50 < r < 150 km, and 1/ r ^0.5 for r > 150 km; and duration as 0 for 0 < r < 5 km, 0.222 r for 5 < r < 50 km, and 10 + 0.015 r for r > 50 km. These estimates can be used to predict ground motion parameters during future strong earthquakes in the region.

The hyperspectral method for analyzing the Earth's surface is very effective in solving problems of classification of both objects located on it and the state of these objects (for example, agricultural crops). However, a full-scale hyperspectral analysis is a very expensive job, and the search for ways to reduce the cost of this procedure is quite understandable. The most logical way is to reduce the number of spectral components - classification features - by choosing (or forming from them) the most informative ones. In this paper, to implement it by using neural network technologies is proposed. By an example of processing a 200-channel hyperspectral image, it is shown that reducing the dimension of the feature space using these technologies makes it possible to achieve high-accuracy classification with the accuracy exceeding that obtained by other known methods.

The article presents a complex algorithm for combining hyperspectral and highly detailed panchromatic images. The algorithm includes preliminary procedures for the selection of contours and subsequent alignment of hyperspectral and panchromatic images at the corresponding points of their contours. As a result of precise alignment, the accuracy of spectral separation of objects in hyperspectral images is also increased. The resulting hyperspectral image has a high spectral and spatial resolution. The results of numerical studies confirm the high efficiency of the developed algorithm.

An important task of a modern radar is the study of approaches aimed at creating broadband radar systems (radars) with an adaptive phased antenna array (APAA) and the development of principles for their construction and algorithms for processing broadband signals in radars with an APAA. The main advantage of such approaches is an increase in the resolution of the system, which makes it possible to classify targets better. The article focuses on the issue of adaptive spatial filtering of active interference in a radar using digital multichannel signal processing in the frequency domain.

A method is proposed for fast bandwidth selection of kernel functions in nonparametric probability density estimation of a two-dimensional random variable with independent components. The distribution laws under study belong to the family of single-mode and symmetric probability densities. The possibility of their optimization is justified on the basis of the analysis of the asymptotic expressions of the mean square deviations of the components of a two-dimensional random variable. Each component is characterized by an optimal bandwidth of the kernel functions, which depends on the nonlinear functional of the probability density. Its functional dependence on the antikurtosis coefficient of a one-dimensional random variable is established. The effectiveness of the proposed technique is confirmed by the results of analytical studies.

A projection shadow method for measuring the diameter of cylindrical objects under conditions of a limited dynamic range of a photodetector is proposed. The method involves the use of telecentric optics and an incoherent light source. The method is based on determining the position of the edge of the object in the image based on the position of the maximum of the derivative of the intensity dependence. Theoretical and experimental estimates of the error of the proposed method are carried out. The error of measuring the diameter of cylindrical objects at the level of 0.3 * 10⁻⁵ has been achieved. The result obtained confirms the efficiency and prospects of the proposed method.

Two methods for measuring the optical response to ammonia of a sensor based on film opal-like silica materials are proposed, and the corresponding devices have been developed. The explanation of the selective response of the sensor to ammonia associated with its high solubility in water has been experimentally confirmed. Experimental results have been obtained on operation of such a sensor with ammonia concentrations from several ppm to 20vol.% with fast response.

Based on the model of equivalent diagrams, the Fraunhofer diffraction patterns (spectra) of extended (in depth) asymmetric slit-type holes with absolutely absorbing inner faces and different input (D) and output (D₁) apertures are calculated in the far field zone. The behavior of the spectrum of an extended object is studied analytically in the case of differences in apertures 2÷Dç =÷D₁-Dç noticeably smaller than the size of the Fresnel zone d_d = Öld (l is the light wavelength, and d is the hole depth). It is shown that, in the range of angles ÷qç<< q_кр= Öl/d, the observed diffraction pattern of an extended object is equivalent to the diffraction of light by a flat slit (d=0) with an effective width D_eff=D+D-q_d /(Ö2p). On the basis of a constructive approximation of the Fresnel integral function, the features of light diffraction by volumetric holes, whose apertures differ significantly from each other: 2÷Dç>> d_d, are studied analytically. Calculations have shown that, in the cases of expanding (D₁> D) and narrowing (D₁< D) apertures, the behavior of the minima of the observed diffraction patterns in the angle ranges ÷qç<÷q_Dç= ÷Dç/d differs only slightly from the equidistant behavior for a flat slit (d =0) with widths D and D₁, respectively. The results obtained can be used in the development of optoelectronic systems for dimensional inspection of plates with holes.

We have made an attempt to give an exact quantitative description and generalization for the specification of the spatial distribution of the x-ray polycapillary lens' spread function for different cases of the quality of its adjustment along angular and lateral coordinates. We have conducted series of experiments on defining the lens' spread function around the spatial areas whose offset from the focal point along the axial coordinate is large. As a result of analyzing results, we have proposed two approximation models for fitting the spread function with potentially good accuracy in the most appropriate cases of polycapillary lens' adjustment. We have demonstrated that the proposed models are universal and agree with the experimental distribution of the spread function with high accuracy by an example of a detailed analysis of three series of experiments on defining the spread function within large spatial areas after three different cases of polycapillary lens' adjustment.

The article deals with the layout of magnetometric gradiometric systems using three-component fluxgates and three-component accelerometric converters. These transducers are also widely used in attitude measurement systems. Basic mathematical models of three-component magnetometers included in the gradiometer structure are proposed, which are suitable for the ideal location of the three-component transducer in the device case. A diagram of the actual arrangement of fluxgates in the gradiometer bogy is shown, and the deviation angles of their sensitivity axes from the basis axes of the device are presented. Refined mathematical models of three-component fluxgate transducers are presented taking into account the angles of deviation of the their sensitivity axes. A technique for calibrating a three-component magnetometer with mechanical turns of the fluxgates on verification devices, installations (rotary tables) is proposed, which makes it possible to set and accurately monitor the required angles of spatial orientation of the device body. The errors of a three-component fluxgate converter are estimated by the method of computational experiment - computer simulation.

The solution of the problem of determining the coordinates of a radio beacon (including a mobile one) in real time using difference-rangefinder measurements taken by a grouping of small-sized unmanned aerial vehicles (UAV) is considered. To form this solution, the following equations are successively derived: equations describing the dynamics of changes in the navigation parameters of the UAV grouping and observers of these parameters based on GPS measurements, equations of motion of the mobile radio beacon and the observer of its navigation parameters, and, at the final stage, algorithms for filtering the UAV motion parameters by satellite measurements and the beacon motion parameters by measurements taken at the UAV. Numerical simulation of the filtering algorithms has shown the possibility of high-precision determination of the coordinates of a mobile radio beacon using the proposed approach.

The approach of applying machine learning methods for prediction of the component composition of the wide fraction of light hydrocarbons in pipeline transportation is investigated. The CatBoost library is used for building a machine learning model that allows the component composition of the mixture to be predicted with an error value of 2.263 by the MAPE metric.

Methods of interactive modeling and visualization of functionally defined objects with the help of a web browser using HTML5 and WebGL are proposed. An application for high-realism models has been developed, which is able to work with an interactive frame rate in real time. The user will be able to instantly change the appearance of the data by manipulating various display properties available through the user interface on the screen. Functional descriptions of objects that allow determining time-dependent geometric shapes, their appearance, and transformations using perturbation functions are proposed and implemented.

The paper presents a comparative analysis of various machine learning algorithms for solving the problem of predicting the heat transfer crisis during boiling in two-phase flows inside channels of various geometries. Twelve classical regression models implemented in the Scikit-learn, LightGBM, XGBoost, and CatBoost libraries, as well as neural network methods are considered. The models are compared with each other, as well as with traditional forecasting methods based on the use of skeletal tables, approximate semi-empirical ratios, and correlation formulas. Possibilities of hybrid models that combine the approach based on domain knowledge with machine learning algorithms are discussed. The results of experiments with a model that combines the CatBoost regressor with one of the traditional methods in a hybrid scheme are presented. The advantage of machine learning models over the traditional approaches is revealed. It is shown that the best performance for all metrics among machine learning models can be achieved by using ensembles of algorithms based on gradient boosting.

The author presents a 3D structured packing with a coordination index equal to 8 to replace effectively a real-life random packing of particles. The notions of vectors of principal stresses and plastic strain rates are introduced. 3D equations of plastic deformation are constructed. They fulfill the model adequacy requirement-zero energy dissipation in the medium of perfectly smooth particles. In the presence of internal friction, the equations lead to a nonassociated flow rule.

The stress-strain behavior patterns in rockburst-hazardous rock mass are described as a case-study of mineral deposits in Gornaya Shoria. The microseismic research data on development of rockburst hazard criteria are described. Geodynamic events are predicted in extraction blocks during basting, with detection of possible damages in underground openings using the obtained patterns of different energy shocks.

Based on the mathematical modeling of the geomechanical condition of a coal face, it is shown that destruction of the face zone occurs in the form of squeezing-out and spalling within an operational cycle. The acoustic noise in the longwall is analyzed, and the noise spectrum peak frequency is determined. The peak frequency is reflective of the size of the damage area in the face zone.

The paper concerns an interpretation of high-precision gravimeter observations in the Upper Kama Potash Salt Deposit. The studies aim to detect the mining-induced softened areas in undermined rock mass. It is found that the gravity field transformants exhibit induced softening areas as flat inclined negative anomalies that intersect the undermined rock mass from top downward. The spatial location of the induced softening areas in rock mass is determined.

For this study, as part of the underground operations, the underground mining sequence was explored for suitability in the Zuuntsagaan mine. Two mining sequences are considered; bottom-up (B-U) and top-bottom (T-B), and the instability of stopes and open pit slopes is evaluated in response to each sequence. For the present rock mass conditions and stress state, with reference to the underground section, the results revealed that T-B sequence has lower ground movements. On the open pit section, the effect of the two sequences is relatively the same while the difference is mainly observed in the underground section.

In this study, a path search algorithm is introduced for exploring the ultimate pit limit using the Lerchs-Grossmann method. In an iteration of the algorithm, each vertex of the solution is randomly moved within a specified neighborhood. The vertices’ motion in such a neighborhood ensures that the formation of abnormal shapes is prevented. Since an open-pit design needs to address geomechanical concerns coincident with economic value maximization, the movements resulting in segments steeper than an allowable slope angle are discarded. For each valid vertex movement, the benefit of the resulted pit limit was calculated. The new position of the vertex is accepted according to a probabilistic regime in order to prevent the algorithm be trapped in a local maximum. Independence of the slope from the block size is one of the main advantages of the suggested algorithm. Hence, the algorithm provides a better mapping to the ore body and results in a higher benefit. The reason is the mobility of the path search algorithm and its high flexibility.

The authors discuss the approved advanced control charts for operational cycles of hydraulic impacting machines. These control charts allow adjusting operational characteristics of the machines either using only pressure back-coupling between the fluid power system and distributor, or in combination with introduced additional pressure control. The article describes adaptive impacting machines equipped with the control charts which allow adjustment of blow energy and frequency subject to properties of a medium being fractured. It is emphasized that to expand the application range of hydraulic impactors, it is required to design high-frequency percussion machines with high impact capacity owing to improvement of distributors and due to transition to the increased power fluid pressure.

The author analyzes spectra of a downhole impulsive vibration source with two power-supply units and an electromagnetic hammer using the Fourier series. The amplitude-frequency characteristics of the impulsive and unbalance-mass vibration sources of adequate sizes are compared. The impulsive vibrator has much higher amplitudes and spectra of output signals than the unbalance-mass vibration source.

The study addresses efficiency of natural cold and the permafrost properties in the Central and Arctic Yakutia in holding of frozen cola in buried storage rooms. The heat transfer modeling takes into account the climate, parameters of a storage room and heat insulation. It is shown that coal thaws less than the host rocks because of its low thermal conductivity. When a storage room is filled in winter, coal will remain frozen for a few years, and heat insulation will greatly reduce the rate of thawing in the overburden. It is emphasized that as against the width and slope of the storage room, its occurrence depth is the main factor to govern the size of the thawed zone by the end of the warm period of storage. Natural cold in the buried storage room decreases coal oxidation, preserves coal properties, and improves energy security of the hard-to-reach areas.

Exploitation of Mutnovskoe Geothermal Field, which is a key asset of geothermal power engineering in Russia, is faced with the problem connected with reduction in pressure in the producing reservoir, which results in decommissioning of production wells. Production capacity of planned wells 3 and 4 km deep for treating deeper horizons in Mutnovskoe Field is predicted. The prediction results are compared with the data of a standard production well 2 km deep in this field and prove the promising nature of the deeper horizons of this reservoir. In particular, essentially greater steam flow rate out is expected in the deeper production well as compared with the standard well. Furthermore, it is expected to produce much more geothermal energy owing to the increased allowable reduction in the reservoir pressure and thanks to additional heat elimination from larger volume of enclosing rock mass of the produced fluid.

Based on the mathematical model of hydro vortex orthokinetic inertia hetero coagulation, the hydro-vortex nozzle parameters air identified for a dust suppression facility for prevention of blasts and induced accidents in mines. Using the similarity theory and dimensionality analysis, the similarity criteria are obtained for the process of dispergating in the conditions of rotational motion of liquid drops. It is shown that the main pulverization efficiency criteria for liquid drop in the hydro vortex nozzle are the Weber number, Laplace criterion and three indicators of inertia and viscosity of liquid, and kinematic similarity. The calculations and tests reveal the possibility of enhancing dispergating efficiency by 15%, reducing the average diameter of liquid drops by 2.5 times, and reducing the liquid flow rate by 10%.

The test data on confined air throw ranges in dead ends are reviewed. It is found that the research findings differ greatly and disable the single-value determination of the allowable lag between the air duct and heading fact at the acceptable accuracy. It is supposed that the discrepancy of the testing data is ensues from the empirical concept of independency of the confined dead-end air throw range from the initial air flow velocity, which is strictly unproved. The supposition is backed with the numerical modeling data on blind roadway ventilation with visualization of air flow shortage at air velocities not less than 0.25 m/s. At the increased capacity of air fan and with the enhanced initial air flow velocity from 5 to 80 m/s, the air throw grows to 56 m. The authors come to a conclusion that the efficient and resource-saving approach to blind roadway ventilation is the increased air supply in air ducts, which makes it possible to extend the distance between the air duct and the face toward safe blasting.

Flotation of pyrite is examined as function of pH and ferrous ion concentration. To explain depression of pyrite flotation in the neutral pH range and at high concentration of ferrous ions, the mechanism of physisorption of a collecting agent is used. It is experimentally determined that interaction products of xanthate and ferrous ions possess different velocities of spreading over the gas-water interface dep0ending on their concentrations and on the solution pH. Furthermore, they have different influence on the velocity of liquid removal from the interlayer between mineral particle and gas bubble. The mechanism of physisorption of a collecting agent discloses the causes of suppressed flotation of pyrite in the neutral pH zone and increased pyrite flotation in the alkaline medium.

The modern structure mineral resource base of solid minerals (TPI) and macroeconomic indicators of the results of their extraction in the territory of the far Eastern Federal district, where 16-18 types of ore mineral raw materials are extracted, are considered. The main production is gold (more than 170 tons in 2019) and silver (more than 930 tons). The total value of the volume of production of all types of minerals (DPI) in monetary terms for the far Eastern Federal district is about 2,4 trillion rubles (45 % of the total gross regional product (GRP) of the region, equal to 5 trillion rubles). There is a slower growth in TPI production in the total TPI. About 3100 enterprises and organizations (without small businesses) with a total number of 142,6 thousand people working in the DPI industry, which is 3.5 % of the total number of employees. The turnover of organizations is more than 2 billion rubles. The largest number of enterprises associated with DPI and the number of employees is observed in the Republic of Sakha (Yakutia). The number of small businesses in the region is almost 2000 with a total of more than 9100 employees. In the region, there is a need to develop intraregional use and processing of raw materials to final products, and create metallurgical enterprises.

A comparative analysis is made of the remote spectral indices in investigating changes in vegetation cover in post-agrogenic biogeocenoses of the Bolshezemel’skaya tundra. In agricultural use, meadow biogeocenoses, compared with the surrounding background areas, were characterized by relatively high indices characterizing the moisture and photosynthetic activity of plant phytomass (NDVI, LWCI, NDMI, and B5). To assess the changes in the amount of dead biomass, the PSRI index was used, the values of which were minimal during the period of agricultural use of meadows during their regular mowing. During self-healing succession in post-agrogenic biogeocenoses, the values of spectral indices gradually approach those of the background sections. In the post-agrogenic period, the values of the LWCI, NDMI and NDVI indices gradually decreased in meadow biogeocenoses, and the PSRI and spectral channel B3 values increased. The dynamics of the spectral indices is affected by the changes in the species composition. In the post-agrogenic period in meadow biogeocenoses, seeded cereal grass stand is thinned out, a shrub layer is formed, and species introduced from surrounding communities become dominant and subdominant. The activation of the self-healing succession of tundra vegetation in post-agrogenic biogeocenoses takes place against the backdrop of climate warming. Statistical relationships are determined, which reflect the influence of climatic parameters on changes in spectral indices in post-agrogenic and background biogeocenoses. A decrease in the severity of the climate is accompanied by an increase in the values of spectral indices characterizing the vegetative activity of tundra vegetation. An increase in the amount of precipitation contributes to an increase in the values of the indices reflecting the supply of plants with moisture.

Gas geochemical research as a method of exploring gas hydrates and determining hydrocarbon deposits A wide range of applications of gas geochemical investigation in science and practice and for solving various geological and engineering problems are considered in the paper. The method we developed represents a package of technical solutions for extracting gas from water and sediments, and for determining the following gas components on a gas chromatograph: methane (CH₄), heavy hydrocarbon gases (C₂-C₅), carbon dioxide (CO₂), hydrogen (H₂), helium (He), oxygen (O₂) and nitrogen (N₂). It is shown that hydrocarbon gases and hydrogen are an indicator of the possible presence of hydrocarbon deposits, carbon dioxide - of the presence of intrusive activity, and helium shows the gas flow from deep horizons and the mantle. Based on the data of gas geochemical studies, the amount of gas hydrates in the upper layer of the gas hydrate strata was calculated. The possibility of using gases to clarify the stratification processes in the sea is shown. The important role of combining the gas geochemical method with other methods for searching for oil and gas fields, mapping fault zones, determining their seismic-tectonic activity and other geological studies is noted.

The paper examines drought trends in Turkey due to climate change. Therefore, forecasting periods of drought, which is one of the major negative side effects of climate change, is essential. The authors used data from drought indicators according to the SPEI (Standardized Precipitation and Evotranspiration Index) for the period between 1901 and 2015. Values obtained at intervals of 1, 3, 6 and 12 months. The data was subjected to several statistical tests: the Mann-Kendall test to determine the direction and significance of the trend, the Theil-Sen estimator to assess the trend slope coefficient, and the Pettitt-test to determine the most probable year of change. The period under study was divided into two intervals (1901-1981 and 1982-2015), and their comparison was performed. A GIS program was used to isolate spatial characteristics from the results obtained. It was concluded that Turkey is mainly divided into two zones of drought, most of which is an increase in moisture in the northern regions, while a decrease in moisture is observed in the southern regions. The trend towards dry periods was more significant until 1981, but since 1981 the situation has changed due to the onset of the trend towards excess moisture, with the exception of southeastern Turkey, where the trend towards droughts persisted.

Rural population dynamics and settlement in Guba-Khachmaz economic-geographic region (Azerbaijan) We analyzed the dynamics of growth in the number and share of the rural population of the Guba-Khachmaz economic-geographical region for 1989-2019. As a result of a sociological survey conducted in the villages, the factors influencing the standard of living of the rural population and its demographic development were studied, and a grouping was carried out according to the size and structure of the population. The corresponding tables, maps and graphs have been compiled. As a result of the economic crisis of the early 1990s, which forced people to leave their settlements, there was a negative balance of migration, and the natural increase in the population in rural areas decreased. Due to its favorable geographical position, the region has good reserves of oil and natural gas, favorable conditions for the development of fruit and vegetable growing, grain growing, animal husbandry and food processing enterprises. However, the problems that arose in the transitional, post-Soviet period, associated with the production of agricultural products, the work of processing enterprises, the provision of services to the population, had a negative impact on resettlement and increased the intensity of internal migration. After gaining independence of the Republic of Azerbaijan in 1991, the socio-economic development of the Guba-Khachmaz region, the availability of sufficient jobs and the improvement of the quality of services in accordance with the needs of the population had a positive impact on the population in the region, created conditions for demographic development.

The necessity of developing measures for the regional development of Kyrgyzstan, increasing their economic potential and improving the infrastructure for industrial and social purposes is shown. In this regard, the development and revival of the economy of towns, including small ones, are considered as a priority direction in the implementation of these goals. It was revealed that the small towns of the country, due to the diversity of historical formation, economic-geographical location (EGL) and socio-economic values, differ from each other. Their main problems are the lack of economic assets, the scarcity of the city budget, remoteness from large centers, unemployment, and a decrease in living standards. The necessity of a comprehensive study of the potential and development prospects of small towns has been substantiated; a thorough analysis of their economic and geographical position is considered as the most important. As a result, the individualizing features of the towns under consideration were revealed. For this purpose, an assessment was made of the economic and geographical position of small towns in the southern region of Kyrgyzstan concerning their well-being in transport, industrial, agricultural, recreational, market and innovation relations. The results showed that, the towns in the region follow from 3.8 (Kochkor-Ata) to 2.3 points (Sulukta) according to the degree of EGL by components. To generalize these series, the towns were combined into three groups: with the most advantageous economic and geographical location; with a favorable economic and geographical location; towns with a comparatively favorable economic and geographical position. It was proved that the degree of profitability of the economic and geographical position of small towns in the region does not have a territorial sequence, i.e., it is not determined by the “center-periphery” pattern. The study enables determination the general potential for the development of the urban economy, planning the construction of infrastructure facilities, and revival of the industrial sector of the economy as a city-forming factor.

We investigated the classifications of geographical sciences to find new scientific directions that are not included in any of their existing classifications. A methodology is proposed that combines three concepts: structuralism, trinitarianism and fractality. The paper provides examples of the Trinitarian approach in geography. Several traditional trends in geography have been identified (“constructive geography”, “applied geography”, and “theoretical geography”) that are not reflected in existing classifications. In our research, we found that the existing classifications do not reflect the trends in the development of science. The names for already existing directions are proposed: “encyclopedic geography”, ”world outlook geography”, “inventory geography”, “subject geography”, and “poly-scale geography”. A study and grouping of cognitive functions of geography: monitoring, popularization, relevantization, conceptualization, methodologization, education, expertise, planning, forecasting, and information support of policy has been carried out. Geographic sciences were united in hierarchical triads, inscribed in each other. An overview of the Soviet and Russian practices of combining geographical areas is given. The classification is presented not as a branching tree, but as a scientific research algorithm looped inside a fractal triangle. Difficulties that arise in implementation of this algorithm are indicated. The historically established logic of the development of geography in “switching” the focus of research to various subjects of study: “structure, process and environment” is substantiated. The differences in interpretation and content between Russian and foreign cognitive geography are revealed. The advantages in the development of both directions are indicated and an attempt is made to combine them in a single algorithm. The harmonious coexistence in geography of two ideological formulas (dichotomy and trichotomy) is demonstrated.