The relevance of this study stems from the need to obtain a comprehensive picture of the state of the cobalt mineral resource base of the Russian Federation. Objective: to examine the current state of Russia’s cobalt mineral resource base, the spatial distribution of cobalt deposits by ore formation types and within ore provinces, and the prospects for national cobalt production. Methods: statistical, graphical, and logical analysis. Results: a consolidated schematic map of Russia is presented, featuring 25 cobalt-bearing provinces and a sample of 150 of the most significant cobalt deposits across various ore formations, along with prospective sites and areas. Key characteristics are provided for the main ore formations hosting cobalt deposits in Russia, as well as for cobalt-bearing provinces and deposits outside these provinces. In Russia, cobalt is extracted as a by-product from sulfide copper-nickel ores (9.2 Kt in 2022). As of January 1, 2023, Russia’s balance reserves of cobalt totaled 1,562.3 Kt. The largest volumes of cobalt reserves are associated with the copper-nickel formation (62.5%) and the silicate-cobalt-nickel formation (19.9%), with the remaining 17.6% distributed among all other ore formations. By province, the Norilsk province accounts for 47.0% of Russia’s cobalt reserves, the Ural province – 24.7%, the Kola and Shoria-Khakass provinces – 7.4% each, the Easten Sayan province – 6.1%, and all other provinces – 7.7%. The Russian Federation has been allocated exploration areas on the international seabed in the Pacific Ocean, where geological surveys are underway in the cobalt-rich ferromanganese crust formation of the Magellan Mountains (resources of 110 Kt Co, with 0.50–0.61% Co) and in the ferromanganese nodule formation of the Clarion-Clipperton ore field (resources of 985 Kt Co, with 0.22–0.29% Co). Despite a substantial base of prepared cobalt reserves, Russia lacks a systematic accounting of forecast cobalt resources, complicating the planning of geological exploration for cobalt. A systematic review of existing geological and geochemical data on known occurrences and points of cobalt mineralization is proposed, with the aim of assessing forecast resources using a unified methodology and producing a consolidated forecast resource balance for cobalt in Russia. For deposits of the silicate-cobalt-nickel formation, where previous assessments were based on maximizing nickel reserves, a reassessment is proposed with 3D special modeling of cobalt distribution as the primary ore component. Such deposits can then be managed specifically for cobalt production. Advancements in underground and heap leaching technologies, as well as bioleaching of cobalt-bearing ores, will enable the development of cobalt deposits with low-grade ores and small reserves, as well as the reprocessing of technogenic materials derived from beneficiation and metallurgical processes. The most promising targets for cobalt extraction using in-situ leaching, heap leaching, and bioleaching technologies are the deposits of the silicate-cobalt-nickel formation.
Maurício Pinheiro dos Santos, Elaine Carballo Siqueira Corrêa, Geovane Martins Castro
et al.
The demand for sustainable and high-performance materials has driven advancements in stainless steel production, including the development of ''green stainless steels'' that reduce environmental impact without compromising mechanical properties. Traditional steelmaking emits approximately 1.8 tons of CO2 per ton of steel, whereas the green manufacturing process used in this study replaces coke with sustainably sourced charcoal, significantly lowering emissions while capturing CO2.This study investigates the fatigue behavior of two green high-strength martensitic stainless steels (HSMSS), AISI 420 and AISI 301LN, which differ in composition, microstructure, and processing. AISI 420 underwent quenching and tempering (QT) to achieve a predominantly martensitic structure, while AISI 301LN, a TRIP steel, was cold-rolled with 54 % thickness reduction, inducing partial martensitic transformation. Despite their similar ultimate tensile strength (σUTS ∼1530 MPa), hardness (∼46 HRC), and surface roughness, their fatigue resistance differed significantly.Through X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and Electron Backscatter Diffraction (EBSD), this study explores how distinct processing routes influence microstructural evolution and fatigue performance. The results provide insights into how sustainable manufacturing methods contribute to fatigue resistance while addressing environmental concerns.
محمد فیلبندی کشکولی, ابوالقاسم کامکار روحانی, علیرضا عرب امیری
et al.
روش مگنتوتلوریک یکی از روشهای الکترومغناطیسی در حوزه فرکانس است. این روش به صورت ژئوفیزیک سطحی غیرفعال است که از میدانهای الکترومغناطیسی طبیعی زمین برای بررسی ساختار مقاومت ویژه الکتریکی زیرسطحی استفاده میکند. چگونگی توزیع مقاومت ویژه الکتریکی، از بهترین و قابل اعتمادترین روشهای شناسایی تغییرات عمودی و افقی در لایههای زیرسطحی است که میتوان با مدلسازی یک، دو و سهبعدی دادههای مگنتوتلوریک، به این مهم دست یافت. در این مطالعه ابتدا روش اُکام سریع را در وارونسازی دادههای مصنوعی مگنتوتلوریک که برای دیاپیرهای نمکی منطقه نصرآباد به روش اجزا محدود تطبیقی تولید شده است؛ مورد بررسی قرار میگیرد؛ سپس این روش بر روی یکی از نیمرخهای دادههای مگنتوتلوریک منطقه نصرآباد اعمال میشود. بدین منظور برای مدل مصنوعی، ابتدا یک مدل اولیه مطابق با مقطع زمینشناسی موجود تهیه شده و با استفاده از روش اجزا محدود تطبیقی دادههای مگنتوتلوریک مصنوعی تولید شده است و در مرحله بعد وارونسازی دادههای تولید شده با روش اُکام سریع انجام گرفته است. وارونسازی با استفاده از روش اُکام سریع نشان داد که این روش در بازیابی سازندهای اطراف دیاپیرها و همچنین در تعیین مرز دیاپیرها و سازندهای اطراف آن به خوبی عمل میکند و روش بسیار قابل اعتمادی است. برای مدلسازی دادههای واقعی منطقه نصرآباد، ابتدا تعیین بعد و جهت استرایک به روش تانسور فاز انجام شد. تعیین بعد دادهها نشان داد که ساختار زیرسطحی کاملا دو بعدی است و همچنین جهت استرایک در جهت N30W مشخص شد. وارونسازی دادهها با روش اُکام سریع و در مد TE+TM انجام شد. نتایج حاصل از وارونسازی به خوبی توانست دیاپیرهای شماره 4 و 5 را آشکار کند. به علاوه برای مقایسه دقیق مدلهای حاصل از وارونسازی به روش اکام سریع با مدلهای حاصل از روش گوس- نیوتون مقایسه شد. نتایج حاصل از این مقایسه نشان داد که مدلسازی انجام شده، روش قوی است.
The article presents the research results of the scientific and pedagogical activities of an outstanding metallurgist of the first half of the 20th century, Professor Vladimir Andreevich Mozharov. The scientist’s formative years and motives for his interest in metallurgy are discussed. Based on archival data, it was found that the active production activity of Vladimir Andreevich Mozharov began after his graduation from the St. Petersburg Mining Institute in 1907. Since the end of 1916, Mozharov headed the Nikolaev Metallurgical Plants in Irkutsk. From March 1920 to the beginning of 1922, Mozharov worked at the Irkutsk Council of National Economy. In the years 1922–1925, Mozharov served as deputy chairman of the Irkutsk Provincial Executive Committee and the Planning Commission. Due to a serious illness of the eldest son, the family was forced to move to Kharkov. In November 1925, Vladimir Andreevich Mozharov became the Chief Metallurgist of the Board of the Southern Machine-Building Trust. From the end of 1929, Vladimir Andreevich worked at the Kharkov Institute of Metals as head of the steelmaking group, head of the department of heat power engineering of metallurgical processes, and then deputy director for scientific work. The most famous work carried out under the leadership of Vladimir Andreevich Mozharov in the 1930s was the development of the technology for producing ARMCO iron and Tonсan technical iron. During the evacuation in 1941–1943, works under the leadership of Vladimir Andreevich Mozharov were carried out to intensify melting and pressure processing of steel ingots, to replace Ukrainian iron ores with Ural and Kuznetsk ones, and to use technology for producing ferroalloys from local ores. After returning to Kharkov, the scientist led the restoration of Ukraine’s Institute of Metals and metallurgical enterprises destroyed by the war. Vladimir Andreevich Mozharov passed away at the end of 1952. The article analyzes some interesting, forgotten and little-known facts of the biography of the outstanding metallurgist, scientist and teacher Vladimir Andreevich Mozharov, which are an integral and important part of the history of metallurgy of the 20th century.
AbstractDigitalization and automation technology offer new possibilities to increase productivity and obtain higher levels of autonomy in mining operations. Introducing autonomous systems into mining is not only a technical problem in terms of effectiveness and efficiency, nor a problem of safety in human-automation interactions. The systems also need to be designed and developed so that they foster healthy and attractive working environments. The design and development phase of new mining technology has not been extensively studied previously. To fill this knowledge gap, we investigated technology developers’ basic assumptions about humans and their interactions with the technology they develop. We conducted five semi-structured workshops within an EU funded project concerned with developing digitalization and automation solutions for the mining industry. The data suggests that many critical functions will still be under human control in future mining systems. The results also indicate increased complexity in the interaction between autonomous systems and humans as the technology becomes more advanced. As a result, we suggest that a human perspective, based on sociotechnical principles, should not only be considered in implementing the technology at mines but also in the early conceptual phases of developing and designing the technology. This will ensure healthy and attractive work environments in the future mining industry.
A comprehensive understanding of cracking mechanisms and the prevention of interfacial microcrack formation are imperative for additive manufacturing of high-performance multi-material heterostructures. This study systematically investigated 316L/CuSn10 heterostructures and identified solidification cracking and solid-state cracking as the predominant mechanisms. Solidification cracking is closely linked to the copper content within the mixing zone, particularly evident at 10% copper content, which heightens sensitivity to solidification cracking due to the widening of intergranular spacing and the elongation of the liquid film channel. Solid-state cracks tend to initiate from pre-existing solidification cracks, propagate along high-angle grain boundaries (HAGBs), particularly within a specific misorientation angle range of 20°–50°, terminating eventually at low-angle grain boundaries (LAGBs). This is mainly controlled by the distribution of dislocations at crack tips, which are dispersed within the grains at LAGBs, and the resulting back stress contributes to crack termination. These findings contribute valuable insights into the cracking mechanisms in heterostructures and offer guidance for the fabrication of crack-free steel-copper components.
The characteristic impedance of a rock is defined as the product of the sonic velocity and the density of the rock. Based on previous studies, this article finds that: (1) For an intact rock, its characteristic impedance is a comprehensive physical property, since it is closely related with strengths, fracture toughness, Young’s modulus, and Poisson’s ratio. (2) For rock masses, their characteristic impedances either increase markedly or slightly with increasing depth. (3) The bursts of intact rocks in laboratory are dependent on their characteristic impedances to a great extent, and strong rock bursts happen mostly in the rocks with large characteristic impedance. (4) Rock burst occurrence in tunnel and mines has a close relation with the characteristic impedances of the rocks. (5) Laboratory experiments on different rock samples show that seismic velocity increases as applied stress rises, and field monitored results from coal mines indicate that in the areas where rock bursts happened, the seismic velocity was increasing markedly before or during the bursts. (7) Drillability of rock depends on the characteristic impedance of the rock and the rock with larger impedance has lower drillability or lower penetration rate. (8) The potential applications of characteristic impedance include evaluation and classification of rock masses, and prediction of rock burst proneness and drillability. Characteristic impedance of rock mass is related to the depth below ground surface. Rock bursts are dependent on characteristic impedance of rock. Characteristic impedance of rock is related to its strengths, fracture toughness, and Young’s modulus. Burst proneness and drillability of rock can be predicted by its characteristic impedance.
Due to the complex and dangerous nature of underground industrial sites, there is an urgent need to improve practical teaching abilities. In this paper, a VR-based interactive teaching and practice environment is proposed for teaching mining equipment processes under laboratory conditions. This environment integrates a digitised design, a virtual simulation platform, and a VR interactive product operation. This VR interactive environment includes the structural cognition of mining equipment, the actual operating conditions, and the actual operation of electronic control. Moreover, this system integrates a series of virtual reality human–machine interaction hardware, so that the students can quickly learn the operating conditions and the states of the actual underground production. This system helps them comprehensively learn the mechanical, electrical, communication, control, and mining methods involved in the mining equipment. Finally, this system provides a virtual practice path for training innovative engineering technicians.
Experimental study of current-voltage (I-V) characteristics and frequency dependences of impedance in copper-Kapton-copper structures in the temperature range 240 – 300 K were carried out. Concentration and mobility of charge carriers thermally excited from traps with exponential distribution by energy in Kapton bulk and metal-Kapton interface and injected from copper electrodes into Kapton were estimated from the fitting of experimental I-V curves within the frame of the model of the space charge limited current (SCLC). Concentration and the width of energy of localized states, arising from the disorder of the Kapton structure, are additionally estimated from the I-V characteristics.
In the process of CO2 geological sequestration, the mechanical properties of coal will be changed after supercritical CO2 interacts with coal. Based on this, in this paper, Brazilian splitting test and variable angle shear test were carried out on anthracite under different test conditions, and the changes of tensile strength, shear peak strength, residual strength, internal friction angle and cohesion of coal under different test conditions were studied and compared from two aspects of dry/saturated moisture content and supercritical CO2 soaking time(3, 5, 7 days). The results show that the tensile strength, shear strength and residual strength of coal decrease with the increase of supercritical CO2 soaking time, but the decreasing amplitude decreases gradually; the degradation effect of mechanical parameters of coal under the action of water + supercritical CO2 is greater than that of drying test group; the internal friction angle and cohesion tend to decrease with the increase of supercritical CO2 action time, but the effect of supercritical CO2 on cohesion is more obvious, but the effect of internal friction angle is less.
The influence of induction heating on the grain boundary character distribution (GBCD) in near-surface regions of a cold-rolled Nickel-based superalloy was researched. After induction heating, most of low-Σ coincidence site lattice (CSL) boundaries were Σ3 boundaries, which were mainly formed via the growth accident model. Moreover, the grain structures evolution during induction heating had a great influence on the evolution of GBCD. At the low strain of 0.1, both the fraction of Σ3 boundaries and grain size increased with the increasing temperatures, while the former was closely related to the better development of grain-clusters at the higher temperature. In addition, the coherent Σ3 boundaries were easier to be formed at the higher temperature during induction heating, owing to their low interface energy and mobility. At the large strain of 0.5, the fraction of Σ3 boundaries also increased with the increasing temperatures, but the grain size exhibited the opposite trend, which was closely related to the well development of static recrystallization (SRX) behaviors. Meanwhile, there was a “symbiotic relationship” between the SRX grains and Σ3 boundaries during induction heating. Through the electrochemical corrosion tests, it was proved that induction heating can contribute to the improvement of corrosion properties of superalloys via increasing the fraction of Σ3 boundaries, while the best corrosion resistance appeared in the samples treated at 800 °C with the strain of 0.5. Moreover, the evolution of both Σ9 and Σ27 boundaries was also closely related to strains and induction heating temperatures, but their fractions were less than 4%.
To investigate the modification of type B inclusions in high-carbon hard-wire steel with Ca treatment, Si-Ca alloy was added to high-carbon hard-steel, and the composition, morphology, size, quantity, and distribution of inclusions were observed. The samples were investigated by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The experimental thermal results showed that the modification effect of inclusion was better in high-carbon hard-wire steel with Al of 0.0053% and Ca of 0.0029% than that in steel with Al of 0.011% and Ca of 0.0052%, in which the inclusions were mainly spherical semi-liquid and liquid CA<sub>2</sub>, CA, and C<sub>12</sub>A<sub>7</sub>. The inclusion size decreased from 3.2 μm to 2.1 μm. The degree of inclusions segregation was reduced in high-carbon hard-wire steels after calcium treatment. The results indicate that the modification of inclusions is conducive to obtaining dispersed inclusions with fine size. The ratio of length to width decreased and tended to be 1 with the increase in CaO content in the inclusion. When the content of CaO was higher than 30%, the aspect ratio was in the range of 1 to 1.2. The relationship between the activity of aluminum and calcium and the inclusions type at equilibrium in high-carbon hard-wire steel was estimated using classical thermodynamics. The calculated results were consistent with the experimental results. The thermodynamic software Factsage was used to analyze the effect of aluminum and calcium additions on the type and quality of inclusions in high-carbon hard-wire steels. The modification law and mechanism of type B inclusions in high-carbon hard-wire steels are discussed.
This paper show on impact of temperature decrease applied in Building Integrate Photovoltaics (BIPV) dimensioned on a photovoltaic solar tile with a superimposed photovoltaic arrangement model, in conditions of simulation of Standard Test Conditions for 1000 W/m2 irradiation, for maximum and minimum summer temperatures of Foz do Iguaçu city during 2017-2018. The simulation (Comsol Multiphysics®) uses different types for material tiles (concrete, polypropylene and PVC) and compares the system considering the influence of the materials in the civil-structural characteristics of the roof. The results showed that the efficiency behavior with temperature variations, produce a decrease of linear efficiency. While the, tile designs proposal has a 16% efficiency value in the datasheet in the same conditions. The results shows a decrease of efficiency and power with the increase temperature in the same conditions of the study, obtaining the respectively value of 0.05%/°C and 0.24%/°C.
ABSTRACT This phenomenological study investigates mining engineering students’ game playing experiences for educational purposes and seeks to understand the essence of their experiences. In this study, three non-gamer and three-gamer mining engineering students were selected through a criterion sampling method, and then data were collected through in-depth phenomenological interviews and focus group interviews. The study showed that visualisation, learning by doing and motivation were the common themes for the benefits of the use of games in education, whereas addiction, underestimation and time management emerged as the possible problems. Motivational elements were found to be challenge, curiosity, control, information seeking, observation, assessment, hypothesis building and decision making that shaped the participants’ experiences. However, games’ effect changed based on the personal characteristics and interests of the students. It can be claimed that the findings of this study indicate promising results in the use of games in mining engineering education.