Home – Home – Jornals – Scientific journal “Vestnik NSUEM” 2024 number 2

This study examines the spatial development of the Russian economy from 2000 to 2020. Besides minor changes, the territorial structure of the economy remained stable, with a decrease observed in the Asian region’s share. Our analysis reveals indicators suggesting macrostructural equilibrium in certain metrics, largely influenced by macroeconomic policies. However, regional development and local associations do not exhibit similar equilibrium traits. We explore potential shifts in the spatial structure of the Russian Federation across three avenues: the concept of a social state by A.G. Aganbegyan, initiatives under the New Economic Policy (NEP-2), and the selective evolution of the multiregional system based on the best regional practices. Using a cognitive model, we scrutinize the roles, positions, and functions of each participant in the “regions - federal center - business structures " system, both independently and within local alliances: “federal center - business structures," “business structures - regions," and “regions - federal center. " We pay particular attention to analyzing the possibilities of distributing competencies and development resources equitably between regions and the federal center, along with outlining the conditions necessary to achieve such balance.

The existing open export-oriented economic model of Kemerovo Oblast-Kuzbass had taken shape by the early 2000s, providing relative resilience to this territory, the largest coal producer in Russia, over the past two decades. However, with an ongoing global energy transition and shifting geopolitical paradigm, the region now finds itself in turmoil and must adapt to new realities. To address this, we have developed three development scenarios for Kuzbass until 2035, all assuming the continued exceptional leverage of the coal sector in the region. Through analysis and scenario quantification against Kuzbass’s economic resilience from 2000 to 2035, we can conclude that a multisector economic model, integrated within an interregional cooperation framework, appears most favorable. Despite projecting modest growth rates, this scenario offers an opportunity for Kuzbass to mitigate strategic challenges and pursue sustainable long-term development. These results obtained can inform the region’s structural policy.

This article delves into the examination of natural, social and economic objects, specifically focusing on the agro-industrial complex and rural areas as parts of a single framework. Through the practical application of a systemic approach, we argue for considering these objects as integral components shaping agrarian-territorial systems (ATS), comprising three primary subsystems: natural, social, and economic. The objective is to stratify and position the ATS of Russian regions across multiple levels. The study hypothesizes that determining common developmental patterns among groups of heterogeneous agrarian-territorial formations is feasible through multilevel positioning. Results, derived from system analysis and multidimensional statistics, validate this hypothesis. The main outcome is an implemented method for multilevel positioning of regional ATS, accounting for intra-cluster and inter-cluster ratios of their key subsystems (economic, social, natural). This methodology makes it possible to identify general developmental patterns within Russia’s agrarian-territorial systems, offering insights applicable to the formulation and revision of subject- and object-differentiated ATS development programs.

This article focuses on examining the trends in demographic aging in Russia following the implementation of the new retirement age and the economic implications behind its increase. Drawing upon data from population censuses and official Rosstat statistics, the study establishes its informational foundation. Analysis reveals features in demographic aging against the new economic threshold for old age across different intercensal periods. Between 1959 and 1970, there is evidence of “aging from below " attributed to a transition to limited fertility rates, alongside “aging from above" as life expectancy increased. The periods of 1970-1979 and 1989-2002 distinctively exhibit characteristics of “agingfrom below." During 1979-1989 and 2002-2010, a decline in the aging of the Russian population is noted. The most recent period, 2010-2021, is the only one to align with the concept of “aging from above, " suggesting a shift towards the aging model typical of economically developed countries. According to the population census of 2021, the number of individuals surpassing the new economic threshold for old age exceeds the count of children under 15. Moreover, this surpasses the previous threshold by 1.6 times. The assessment of demographic burden underscores the necessity of raising the retirement age, aiming to mitigate age discrimination in employment, harness the resource potential of the older generation, and promote healthy and active longevity. However, any increase in the retirement age must be accompanied by an adequately proportional rise in the average pension.

In 2020, Russia experienced a deviation from the positive trend of annual growth in life expectancy observed between 2006 and 2019. Despite this downturn, the Republic of Tatarstan stands out with the highest life expectancy indicators in the Volga Federal District, surpassing the national average. To clarify the regional nuances of gender-based disparities in this sphere, our article conducts a calculation and a component analysis of mortality and life expectancy dynamics in Tatarstan, focusing on sex, age, and nosological indicators. Specifically, it seeks to identify probable determinants amidst the COVID-19 pandemic during 2020-2021, comparing them with pre-pandemic patterns. Utilizing decomposition methodology, we assess the relative contributions of cardiovascular diseases, oncology, COVID-19, and other causes of death to the growth dynamics in the average expected lost years of life expectancy. Additionally, findings from the sociological study “Demographic Well-Being of Russia" underscore differences in self-preservation behavior between men and women in the Republic of Tatarstan. Based on these insights, we have developed a draft republican strategy aimed at addressing men’s health concerns, outlining key objectives to foster optimal health conditions for males across all age groups. Additionally, the authors contributed to the formulation of the national Strategy of Action for Saving Men and Supporting Responsible Fatherhood, in collaboration with the Institute of Demographic Research of the Federal Research Sociological Center of the Russian Academy of Sciences.

This study examines the image and thematic areas of youth social activism forming within the information landscape of Arctic regions. Through the analysis of online publications, the authors aim to delineate the attributes of social activism among young individuals in Arctic communities. The findings of the study yield the following insights. First, the image of social activism among Arctic youth primarily stems from mass media and governmental sources, lacking representation from any websites of educational institutions, scientific bodies, non-profit organizations, or business ventures. Second, event-based and episodic initiatives prevail, which does not depict best practices of social activism and their societal contributions. Third, prominent themes encompass multifaceted cultural and professional events, suggesting a sense of identity among Arctic youth, yet coverage of youth entrepreneurship, research, journalism, blogging, volunteering, leisure, IT, and project activities is scant or nonexistent. Forth, information on youth social activism tends to spotlight regional endeavors, while initiatives at national and interregional levels often highlight activities beyond the Arctic region. These conclusions are complemented by conjectures regarding potential causes and repercussions of the identified phenomena, approached from sociological and sociolinguistic perspectives.

The article carries out an assessment of the territorial distribution and scale of various types of spatial labor mobility within the Moscow agglomeration, utilizing data from mobile operators. Special attention is given to daily and weekly pendulum labor migrations, seasonal workers, and remotely employed citizens. The analysis reveals that a significant portion of Moscow Oblast participates in the labor market of the metropolitan agglomeration through weekly and longer pendulum correspondence, rather than daily commutes. Functionally, areas connected with Moscow by daily labor rhythms cover regions within a distance of up to 30-40 km from the Moscow Ring Road. Examination of labor movements from several major centers in the Leningrad direction, situated at varying distances from Moscow, shows that beyond the fortieth kilometer from the Ring Road, residents tend to gradually orient themselves towards local labor markets rather than take part in daily commutes, and extended cycles of pendulum labor correspondence, or semi-seasonal work, become more prevalent. While full-fledged seasonal work (“otkhodnichestvo") is less common than semi-seasonal work among Moscow Oblast residents, its significance within the agglomeration is enormous. The number of seasonal workers there is comparable to the number of semi-seasonal workers (0.7 million people), with their recruitment area extending beyond the boundaries of the agglomeration system, encompassing not only neighboring territories around Moscow Oblast, but also constituent entities across Central and Southern Russia, as well as the Volga Region. Overall, the total number of citizens that are engaged in extended labor commuting cycles and interact with the metropolitan agglomeration is comparable to the daily pendulum migrations to the capital (1.2-1.5 million people), with an additional 0,7-0,9 million individuals participating in the capital’s labor market remotely. The proposed method of comprehensive examination of the entire hierarchy of labor spatial relations can serve as a valuable tool for further integrated analysis of the poly-hierarchical system of pendulum labor migrations in Moscow or any other agglomeration.

The article explores the nuances of implementing environmental regulations through economic instruments of nature management in North Asian countries and regions. It analyzes trends in environmental and economic development, as well as the application of market instruments for nature management. Through content analysis of strategic development plans, the paper evaluates the extent to which the socio-economic development of Russian regions in North Asia aligns with the principles of a green economy. Additionally, it ranks regions based on the inclusion of goals, priorities, development directions, and tools related to the green economy and associated concepts in their strategic development plans. The approach introduced by the authors holds potential as a tool for assessing the degree to which regional development adheres to the principles of a green economy. This framework could inform managerial decisions in environmental and economic development.

The sociocultural values of specially protected natural areas (SPNAs) can translate into various outcomes for both society and the territories they inhabit. This study aims to evaluate the patterns and nuances in how the population perceives the sociocultural values of SPNAs in cities where these areas are located. In the first part of the article, we assess the relationship between subjective indicators such as health, active lifestyle, and participation in environmental projects on the one hand, and the proportion of protected areas within the city boundaries on the other. This analysis is conducted across clusters of cities. Similarly, the correlation is examined among the same 87 cities but grouped by the extent of their SPNA network, allowing us to pinpoint the most influential SPNA area in shaping public perception of their values. The second part of the study focuses on understanding how the scientific and pedagogical communities perceive SPNA values in individual cities. We divide the entire SPNA network of these cities based on the level of visitation by tourists and local residents. Moreover, age-related characteristics regarding the perceived significance of protected areas are identified. These findings offer insights that can be utilized to refine the management systems governing SPNAs within urbanized regions.

Defining economic specializations at the level of administrative-territorial units in Russia’s major urban agglomerations is a pressing concern for regional scientific research. This stems not only from the concentrated socioeconomic activities and ongoing economic transformations within these areas but also from the need to pinpoint the types of economic activities (specializations) that will foster further growth and development. However, limited access to statistical data complicates research efforts focused on determining specializations at the municipal district level. To address this challenge and calculate the specialization coefficient, we utilize the “number of business entities belonging to legal entities" indicator per type of economic activity, sourced from the SPARK-Interfax information group’s regional breakdown of Russian Federation constituent entities. The St. Petersburg agglomeration includes 18 districts of St. Petersburg and 7 districts of Leningrad Oblast (Vsevolozhsky, Kirovsky, Tosnensky, Gatchinsky, Volosovsky, Lomonosovsky, and Sosnovoborsky urban districts), each with administrative centers located within ninety minutes of driving distance from the core’s central point (Palace Square, St. Petersburg). Specialization coefficient calculations were conducted for each district of the St. Petersburg agglomeration, revealing distinct specializing types of economic activity. To facilitate analysis, the districts were conventionally grouped based on historical and geographical administrative-territorial principles, resulting in four categories: the historical center, the middle zone, the suburban zone, and the peripheral zone. This grouping allowed for an examination of specializations aligned with spatial and functional patterns typical of urban agglomeration development. The findings from this research hold practical implications for regional and local government bodies in formulating spatial development strategies and documents. They can also be helpful to business entities seeking optimal organization (enterprise) locations.

The market as such is a social institution that facilitates the exchange of different types of goods and services. In general, the labor market should be considered as an integral part of the market economy, functioning in it along with other markets - resources, goods, securities, etc. It is a system of social relations between employers, employees and the state present on the market, reflecting and achieving a balance of interests between them for a given period, ensuring the reproduction, exchange and use of living labor. It has its own specific internal structure, the main elements of which are: the demand for labor; the supply of labor; the price of power; labor cost; competition. The transition to a market economy has led to the fact that for the bulk of the economically active population, labor has become wage-based, depending on the ratio of supply and demand and economic conditions. This is where the employee sells his workforce to the employer. Today, the labor market is undergoing rapid changes associated with a number of global factors such as a change in technological structure, digitalization of the economy, demographic and age-related changes in the structure of the population. It adapts to external conditions, for example, the consequences and limitations of the coronavirus epidemic, creates new formats of labor relations, in particular, the format of self-employment set by national goals, and forms relevant requests to employers and job seekers, the answer to which is not always obvious. Responding to the creation of high-performance jobs, the labor market increases the proportion of atypical forms of employment, which are becoming more and more in demand as a result of more flexible legal regulation of labor relations. The model of labor market flexibility focuses mainly not on the macro, but on the micro level, not on external, but on internal labor markets, not on quantitative, but on qualitative adaptation of employment. The International Labour Organization links modern transformations in the world of work with such areas of the economy as the informal economy, non-standard forms of work and other new forms of employment. All of them have qualities that destroy standard employment from the inside and expand non-standard employment. The consequence of this is the forced employment of large masses of workers in conditions of partial or complete loss of their labor and social rights provided for in standard employment. The International Labour Organization estimates the negative impact of precarious employment on modern employment to be higher than unemployment.

The purpose of this article is to identify the main problems and directions of transformation of the international transport and logistics system in modern geopolitical conditions. The reasons for changing the directions of international transport corridors, their turn to the East and Asia are discussed. And although the volume of cargo transportation is increasing, there are objective reasons limiting its growth: organizational barriers, difficulties in financial servicing of supply chains, inconsistency of customs procedures, infrastructural obstacles, geopolitical and territorial disagreements.

In the context of constant changes and the need to quickly respond to challenges from the outside world, the need for constant training and development of personnel becomes mandatory for business. Identification of basic directions for the development of training and development systems, consolidation of best practices, including the example of Rosatom, will make it possible to formulate recommendations for domestic companies that are faced with the need to create and develop such effective systems. The methodological basis of the study was the work of a research group of scientists from the Higher School of Management of St. Petersburg State University under the leadership of E.K. Zavyalova and the Higher School of Business of the National Research University Higher School of Economics in the studies of V.S. Katkalo. In-depth interviews with managers of the training and development function of domestic large manufacturing companies, analysis of cases and documents of enterprises that have created a dedicated structure that implements the training and development function. The information base of the study consisted of materials from 20 interviews with HR directors and directors of corporate universities/educational centers, and the results of an analysis of the experience of 9 companies. The analysis showed that the functions of development and education, its representation and place in the organization’s system largely depend on the general director or HR director. Training is not a priority area for working with personnel; in most cases, the training and development function is a service function. The number of company personnel and the size of the training and development function are weakly related to each other, as is the connection of the latter with the effectiveness of the function. The findings of the study may be useful for organizational leaders and HR directors planning to develop the education and development function in the company.

A comprehensive numerical and experimental study of NO_x formation during hydrogen combustion in a cylindrical combustor with a developed microflame burner is performed. Experimental data are obtained for various distributions of the fuel between the baseline and pilot contours of the burner. Numerical investigations of the combustion and NO_x formation processes in the combustor are performed for regimes corresponding to numerical studies. The computations are performed in a steady-state formulation with the use of the Reynolds-averaged Navier-Stokes equations for turbulence modeling. In hydrogen combustion simulations, the rate of fuel mixing with air is taken into account by using a similarity criterion related to diffusion (turbulent Schmidt number). The normal velocity of flame propagation is specified in accordance with the temperature and composition of the fuel-air mixture. The influence of the turbulent Schmidt number on the results calculated for nitrogen oxide emissions is studied.

A comprehensive numerical and experimental study of the flame flashback boundaries in combustion of a premixed methane-hydrogen flame in a vortex burner with flow swirling and also in a model combustor, which is a prototype of low-emission combustors with fuel premixing is performed. Based on the results of the study, recommendations are given, which allow the flame flashback to be determined with an error smaller than ±5%. These results can be used to increase the accuracy of determining the flame flashback in combustion of the methane-hydrogen fuel at the stage of preliminary design of combustors for aviation gas-turbine engines and propulsion facilities.

The results of using the developed multichannel panoramic flow imaging system with combustion in a model channel on a test rig. The main emphasis is on the principles of operation of imaging system components, features of their choice, and requirements to the system and parameters of its components. The advantages and disadvantages of the developed multi-channel imaging system are discussed. Possible ways to modify its components in order to more accurately describe combustion are presented.

The conducted research relates to the works on obtaining consolidated materials by the method of self-propagating high-temperature synthesis (SHS) with subsequent compaction of hot products (SHS compaction). By the method of SHS compaction of mechanically activated mixtures of Ni and Ti powders, pore-free samples of titanium nickelide with a diameter of 70 mm and a thickness of 8 mm were obtained. The combustion of the Ni + Ti mixture was carried out in a reaction mold without preliminary heating and a protective environment. The effect of mechanical activation in a ball mill on the characteristics of the mixtures and the combustion parameters was studied. The analysis of the microstructural characteristics showed that an increase in the reactivity of Ni + Ti MA mixtures and the implementation of exothermic interaction in the SHS mode are due to a decrease in the crystallite size in Ni particles, an increase in the dislocation density in them and the formation of composite Ti-Ni particles. The maximum combustion temperature of the reaction mixture is 1150 °C, the average combustion velocity is 3.5 cm/s. The main phases of the synthesized alloy are Ti₂Ni, NiTi and Ni₃Ti. The compressive strength of the samples is 1350 MPa, the Vickers microhardness is 11.1±1.2 GPa.

The influence of mechanical activation and amount of Fe + Co + Cr binder on the combustion rate and maximum temperature, sample elongation during combustion, composite particle size and mixture yield after activation, phase composition and morphology of synthesis products in the Ni-Al-(Fe-Co-Cr) system was studied. Mechanical activation of the Ni + Al + x(Fe + Co + Cr) mixture allowed the samples to burn at room temperature with a Fe + Co + Cr binder content of up to 40%. Activation of the mixtures increased the combustion rate and temperature, sample elongation and porosity, and decreased their strength. An increase in the Fe + Co + Cr binder content in the activated Ni + Al + x(Fe + Co + Cr) mixture led to an increase in the mixture yield after mechanical activation, a decrease in the composite particle size and an elongation of the synthesis product samples. The dependence of the combustion rate of activated mixtures on the content of the Fe + Co + Cr binder is non-monotonic, and has a maximum at a binder content of 10%. High-entropy alloys - solid solutions based on intermetallic compounds NiAl and Ni₃Al - were synthesized by the SHS method.

The paper describes the production of aluminum matrix composite materials containing metallic glass particles of the composition Fe₆₆Cr₁₀Nb₅B₁₉ by successively applying mechanical activation of the initial powders in a planetary mill and spark sintering. During sintering at 540 °C, the metallic glass particles are completely or partially converted into the intermetallic compound Fe₄Al₁₃. Composite materials sintered from a mixture of Al + 20 (vol.) % Fe₆₆Cr₁₀Nb₅B₁₉ are characterized by anisotropy of mechanical properties: the yield strength in compression, microhardness and deformation at failure in the pressing direction during sintering are 550 MPa, 200 HV and 14.2%, respectively, while in the direction perpendicular to the pressing direction, these characteristics are 740 MPa, 250 HV and 2.2%

The composition of combustion products of calcium hypophosphite Ca(H₂PO₂)₂ with sodium or potassium nitrates or nitrites as oxidizers in air at atmospheric pressure has been studied. Synthesis was carried out to obtain double phosphate of the composition Na(K) CaPO₄. Mixtures of powders with zero oxygen balance were prepared using, if necessary, an additional amount of ammonium nitrate. The phase composition of condensed combustion products was studied by X-ray powder analysis. The mixtures burned stably at atmospheric pressure releasing P₄O₁₀ aerosol. The combustion products were melted white particles up to 1 mm in size. In condensed combustion products were found to contain the double phosphates NaCaPO₄, Na₂CaP₂O₇, K₂CaP₂O₇, and KCaPO₄ and calcium pyrophosphates Ca₂P₂O₇.

A physical-mathematical model of natural gas flow in methane-containing coal seams is built using the concept of interaction of geomechanical and gas-dynamic factors in coal degassing process. Methane flow calculation is performed, and it is found that the cause of the decrease in the methane yield is the increase in stresses around producing wells, the change in the occlusion pressure of gas in cracks and pores, as well as the piezoconductivity of rock mass.

Within the framework of the elastoplastic model, the authors propose a theoretical description procedure for troughs of ground movements at high gradients of subsidence. The approach uses reduction of shear modulus in rock mass bordering a movement trough. The pre-requisite for the shear modulus reduction in such areas is the increased mining-induced pressure, which initiates damage and aggravates the defect structure of rocks through widening of micro-cracks, inter-grain contacts, etc. The estimation procedure of the induced reduction factor for the shear modulus uses the comparative analysis of ground slopes. This approach enables a reliable calculation of ground movements at high gradients of subsidence, and ensures the adequate stress-strain analysis of undermined rock mass, including location of plastic deformation zones.

Using a gradient-type model, the authors solve a boundary-value problem on stress redistribution in rock mass during mining. The elastoplastic model takes into account local discontinuity. The condition of smoothness of the displacement field is essentially weakened-instead of one smooth field of displacements, two-dimensional kinematics is described using two independent smooth fields. As a consequence, the model receives a structural parameter including the dimension of length and characterizing local bends of unit volumes. The article gives examples of plastic strain calculations in adjacent rock mass with identification of the increased stress concentration zones. It is shown that inclusion of local bends leads, on the hand, to the reduction of plastic shears in adjacent rock mass and, on the other hand, to deeper expansion of high stress concentration zones in rock mass.

This research paper will cover the possible causes which can lead to subsidence above old abandoned board and pillar coal mines at a shallow depth. The research includes the calculation and analysis of the factor of safety for pillars using ANSYS and Monte Carlo Simulations for ascertaining subsidence. An old abandoned coal mine of South Eastern Coalfields Ltd. (SECL, a subsidiary of Coal India Limited) was considered for the study of coal pillar fatigue and eventual crushing of pillars over a long duration of time, simulation analysis of stress and strength of coal pillars over a long period, change in behavior of factor of safety as the dimension of the pillars changes.

The authors assess abrasiveness of sand with continuous acoustic emission recording during LCPC test with crushing of a 500 g sample by a straight wheel in a metal barrel. The informative parameters are the acoustic emission spectra averaged over a number of instances at different times of crushing, and over six frequency bands from 2 to 500 kHz. The obtained coefficients of multiple regression coefficients allow calculating wear of a cutting tool and the LCPC abrasion coefficient LAC for different crushing times by the averaged amplitudes of the AE spectrum components. This method is applicable in tunnel boring, hole drilling and other practices involved in real-time control of ground abrasiveness and wear of cutting tools to be replaced in a timely manner.

According to classification of coal seams with solid inclusions, all mine seams are divided into three groups subject to the size and content of the inclusions in a seam. It is found that fracture efficiency and maximal loads depend on the mineral type of inclusions. Carbonate and pyrite inclusions are fractured in a few cuts, while carbonate-pyrite inclusions are usually broken in a single cut. The loading of a pick is approximately 1.6-1.7 times higher in cutting pyrite inclusions as compared with carbonate inclusions. The authors identify five basic types of the pick-solid inclusion interaction: central and edge cut; touch; tear-out; extraction. The highest loads appear in cutting of solid inclusions and should be taken into account in designs of cutting heads and power drives of mining machines.

The article studies effect of expedient inter-hole delays on seismic safety of blasting in open pit mining. The actual delays in non-electric initiation systems are measured instrumentally, and the results are processed using computer modeling. The domestic and foreign information on deviation of the actual and design delays is reviewed. The computations prove the increase in the factor of seismic safety in blasting with longer inter-hole delays. Additional instrumental measurements of seismic vibrations should be performed to evaluate actual blast patterns at a full and lab scale, with the analysis of quality of rock fragmentation by blasting.

In this study, the change in the strength value of 11 pyroclastic rocks from the Cappadocia region, where pyroclastic rocks are commonly found, using the freeze-thaw (F-T) test was investigated after applying 5, 10, 15, 20 and 30 F-T cycles. The uniaxial compressive strength (UCS) of the samples after applying the F-T cycle was estimated using the point load test (PLT) values. With the developed empirical relationship, it was identified that the PLT values predicted UCS with a high correlation coefficient of 0.8663.

Equipment of open pit placer mining is examined. The process designs of incremental end-to-end gold recovery from placer sands are substantiated. In structurally complex extraction blocks, stripping is carried out first, and then, the limits of rich sand pockets are adjusted during the second-phase denser-grid exploration. Different-grade sands are extracted selectively. Extraction and transport of standard-grade and low-grade sands, which are the bulk of an operating block, is implemented by heavy-duty bulldozes; the standard-grade sands are sent to sluicing, and the low-grade sands are used to make heap leaching piles. High-grade sands, which make a small volume of an operating block, are transported to a multi-stage processing facility for the high-efficiency gold recovery. Tailings of standard-grade and high-grade sand processing, with mainly fine and very fine gold content, go to heap leaching.

In this study, point cloud data were obtained from an underground limestone mine using a laser scanner. A numerical analysis was performed using discontinuous and continuous models, and the stability of two pillars located in large underground openings was analyzed. The safety factor was 1.0 or higher in both analyses, and the displacement was insignificant compared to the pillar size, confirming the pillar stability. Additionally, the safety factor of the discontinuous model was reduced by approximately 30% compared to that of the continuous model, and the displacement was increased by approximately 40%. The change in the safety factor was examined by applying the minimum, average and maximum mechanical properties of the investigated rock mass. The analysis determined that an average change of 50% occurred in the safety factor when the minimum and maximum mechanical properties of the rock mass were compared.

For the operative bucket of a 2nd size-group hydraulic excavator, the impact capacity of percussion mechanisms, required for cutting rocks with the compression strength up to 60-80 MPa, is determined. The structure and parameters of hydropercussion mechanisms are chosen. The proposed inter-connection for the hydropercussion mechanisms and the hydraulic power station contains activation valves for each of the mechanisms, and a pressure reducing valve at the inlet. A simulation model of the system of hydropercussion mechanisms is built, and the performance and characteristics of the model are calculated at different rates of power fluids and pressures of the reducing valve. The authors prove the efficiency of the proposed design and connection of hydropercussion mechanisms in the excavator hydraulics and validate the adjustability of the impact capacity of the mechanisms through setting-up of pressure of the reducing valve.

A bench tester is designed for the examination and investigation of a borehole impulsive source of vibrations, composed of an electromagnetic impact block and hydraulic power units. The bench tester simulates operation of the vibration source in an oil well, at the depths greater than 1000 m, with automated pressure control in the system. The implemented research allowed reaching the failure-free operation time of the vibration source in the well up to 150 h and longer, determining the ranges of the impact frequency and energy adjustment depending on the feed voltage, and recommending the operating frequency of the source to ensure proofness of cement stone of the well casing. The obtained nomograms enable correlating the maximal duty cycle of the borehole impulsive vibration source with the coil current density and the heat transfer coefficient to maintain temperature balance of the hammer at permissible temperature of electromagnets.

The methods of increasing energy and operation parameters of a pneumatic hammer with an air distribution valve are reviewed. The algorithm of restructuring impact capacity of a pneumatic hammer with an elastic ring valve in the back stroke chamber of the hammer piston is proposed: it is suggested to use a feed source with an increased-pressure energy carrier. The algorithm was employed in designing and manufacturing a prototype model of the hammer. The actual operation factors of the prototype model are determined on a lab-scale bench tester: impact energy, impact frequency, energy carrier flow rate. After processing of indicator pressure charts, compressed air flow rate per unit energy output is assessed.

The article describes the experimental results of using synthetic sorbents made of hypercrosslinked polystyrene copolymers with divinylbenzene and vinylpyridine for recovery and separation of valuable components (Zr, Σ REE) from pregnant solutions of nitric acid leach of eudialyte. It is found that at the stage of Zr and Σ REE recovery from pregnant solutions, the most effective are resin Puromet MTS 9500 and bifunctional strongly acidic cation exchanger Purolite C160. Regarding Puromet MTS 9500, a flowsheet of step-by-step gradient elution of the sorbent saturated with valuable component is proposed. The flowsheet enables the outlet solutions of Zr and Σ REE at the recovery of 97.7 and 81.1%, respectively. Efficient separation of REE to subgroups is reached with resin VP-3AP.

The authors justify theoretically and experimentally the promising modification methods for saponite-pillaring and thermal treatment. These methods ensure production of sorbents with high capacity of cation exchange relative to cations of rare earth elements. The mechanism of pillaring and thermal treatment of saponite-bearing products at the temperature of 625 ⁰C includes expansion of the mineral layers, generation of additional acid and oxidation-reduction centers (pillaring), as well as restructuring with formation of meta stable phases (thermal treatment). Optimization of application parameters of the sorbent (pH, sorbent-to-solution ratio) ensures efficient recovery of some REE from pregnant solutions of eudialyte concentrate leaching at the adsorption capacity up to 18.8 mg/g.

The authors investigate a new reagent-modified water-soluble polymer of polyvinyl caprolactam (PVCL)-as a collector in flotation of gold-bearing sulfide ore. Modified PVCL is obtained by solid-phase modification of poly(N-vinyl caprolactam) by thiourea. The electron scan and laser microscopy identified adsorption of PVCL at gold grains applied artificially to the surface of polished sections of pyrite. It is found that PVCL facilitates selective aggregation of gold-bearing minerals from fine slime, and more than 99% of gold goes from fine slime to sand at the content of 3.54 g/t. The use of PVCL together with butyl potassium xanthate (PVCL 30 g/t, BPX 200 g/t) in flotation of finely ground gold-bearing ore from the Olimpiada deposit improved the quality of the concentrate: gold content increased from 19.9 to 29.5 g/t and gold recovery increased from 81 to 95%. The joint application of modified PVCL and BPX results in the gold recovery higher by 14%, concentrate quality improved 1.5 times and in the gold content of tailings reduced to 0.15 g/t.

The authors validate the use of magnetic hydrocycloning in extraction of weak magnetic-responsive slime particles from finely dispersed magnetic suspension. Efficiency of a lab-scale magnetic hydrocyclone with regular electromagnetic system of copper wires on the cone, without superconductive materials involved, in extraction of magnetite particles -20 µm in size is described. The test results prove recoverability of hematite and other weakly magnetic minerals in magnetic hydrocycloning at the required flux density of 2-10 T created by a superconductive magnetic system under conditions of cooling at the liquid nitrogen temperature, which minimizes energy intake of magnetic separation. The use of the superconductive magnetic system and high-temperature materials on the hydrocyclone cone enables efficient extraction of weakly magnetic particles, for instance, red mud -10 µm in size.

The article describes a solution to the problem connected with the earlier proposed method of remote appraisal of hydrocarbon reservoirs by passive seismic. It is shown that a linearity only appears in a certain frequency range and fails fast when the latter expands. It is found that the linearity is connected with the non-Gaussian behavior of seismic noise in the isolated specific frequency range. The author proposes a method to asses an informative frequency range using experimental data, polyspectral analysis and surrogate time series.

The geomechanical monitoring system of ground surface in the area of the Atasu Iron Mine lease is described. The actual undermined ground surface is examined using drone photogravimetry. The sources of ground deformation are determined from independent measurements within a created temporal reference test site aligned with GNSS coordinates. High-precision geometric levelling is accomplished using metal benchmarks set as three levelling lines along and across the strike of ore bodies with a view to revealing rock mass movements in the course of underground mining.

Re-usability of wastewater from open pit coal mines and surface flows is discussed with regard to the adopted water circulation cycles. The analysis of process flow charts of open pit coal mining and water use made it possible to identify the main trends of wastewater application and volume reduction. A flowsheet of integrated treatment and distribution of wastewater in open pit mines is developed. It is shown that efficient management of intramine water consumption and expansion of cooperation with wastewater consumers can allow high-rate recycling of industrial wastewater. The proposed activities can help reduce environmental pressure in the coal mining areas, and decrease amount of wastewater which need advanced treatment down to maximum allowable concentration of harmful agents in fishery water bodies.