Vol 274

Achieving technological sovereignty implies accelerating innovation and reducing import dependence. An effective tool for addressing these challenges is local content policy (LCP). The purpose of this study is to assess the impact of LCP on innovation activity in oil and gas companies and to provide recommendations for enhancing the effectiveness of this policy in Russia. The paper analyzes the influence of LCP on innovation levels in the oil and gas sector, drawing on examples from 10 countries. A positive short-term impact of LCP on innovation was identified in Brazil, Malaysia, and Saudi Arabia, with long-term effects observed in China and South Africa. Recommendations for improving the effectiveness of LCP in Russia are supplemented with a methodology for calculating the level of technological sovereignty. A refinement of the method for solving the «responsiveness» problem, incorporating the level of localization, has been proposed.

The mineral composition of metacarbonate rocks (silicate marbles and carbonate-silicate rocks) of the Khapchan series (southeastern part of the Anabar Shield) was studied, and the PT (pressure and temperature)-parameters of their formation were established. Silicate marbles contain calcite, dolomite, forsterite, clinohumite, spinel, enstatite, diopside, pargasite, meionite, phlogopite, and feldspars. Carbonate-silicate rocks are composed of calcite, quartz, feldspars, diopside, grossular, marialite, and vesuvianite. Carbonate-silicate rocks are significantly enriched in SiO2, Al2O3, FeO, Na2O, K2O, TiO2 and contain less MgO, CaO than silicate marbles. A difference was revealed in PT-parameters determined for silicate marbles (temperatures 700-900 °C and pressure no more than 8 kbar) and for carbonate-silicate rocks (temperatures 680-820 °C, pressures 8-15 kbar). Silicate marbles have a primary sedimentary nature, as evidenced by their rare-element composition and the presence of fragments of host terrigenous rocks. There is no doubt about the primary sedimentary nature of carbonate-silicate rocks, which are very similar in REE distribution spectra and in rare-element composition to silicate marbles. A number of features indicate that metacarbonate rocks have undergone metasomatic alteration. Thus, in silicate marbles, reaction rims are observed around orthopyroxene, forsterite, potassium feldspar, as well as quartz veins bordered by accumulations of phlogopite, feldspars, and diopside. In carbonate-silicate rocks, the development of secondary marialite on potassium feldspar has been established; the rare-element composition of garnet may indicate its metasomatic origin.

Selection of the type and parameters of the stripping scheme is one of the most complicated tasks in design of the mining of steeply dipping deposits. The stripping scheme adopted in the project largely determines the capital and operating costs of mining and affects the development strategy of the company in general. The greatest number of alternative stripping methods are associated with mining conditions of reserves in large steeply dipping deposits, which were exploited for several decades. Current approaches to selecting the method and scheme of stripping involve the use of a specific type of transport; however, the type and model of the vehicle are not taken into account in the current classifications of stripping methods and schemes. It is necessary to develop a systems approach to selection of the stripping methods for mining steeply dipping deposits. The purpose of the study is to substantiate the parameters and develop a multifactorial criterion for assessing the stripping system for selecting an alternative for the development of a mining plant. The article proposes an approach in which the choice of the opencast transport, substantiation of the stripping method and scheme will be considered as part of the stripping system, which will allow a comprehensive solution of the problems of increasing the efficiency of mining at different stages of quarry operations. A refined definition and structure of the stripping system are proposed. As a criterion for assessing the efficiency of the stripping system, a rank coefficient is selected that takes into account the target values, the weight of parameters and groups included in the calculation, the computation of which is based on the use of a combination of multicriteria analysis methods. The approach allows considering not only the economic performance, but also other factors, which largely determines further development of the plant. The study primarily focuses on deep open pit conditions of ore deposit mining. The established rank allows choosing the most efficient strategy for the development of mining plants.

The paper presents an analysis of the advantages and limitations of additional measures to intensify the transportation of the backfill hydraulic mixture flow. The results of the analysis of the conditions for using pumping equipment to move flows with different rheological properties are shown. Generalizations of the methods for influencing the internal resistance of backfill hydraulic mixtures by means of mechanical activation, as well as increasing fluidity due to the use of chemical additives are given. The article presents the results of studies confirming the feasibility of using pipes with polymer lining, which has proven its efficiency in pumping flows of hydraulic mixtures with different filler concentrations. An analytical model of hydraulic mixture movement in the pipeline of the stowage complex has been developed. The trends in pressure change required to ensure the movement of hydraulic mixture in pipelines of different diameters are exponential, provided that the flow properties are constant. The effect of particle size on the motion mode of the formed heterogeneous flow, as well as on the distribution of flow density over the cross-section, characterizing the stratification and change in the rheological properties of the backfill hydraulic mixture, is assessed. An analytical model of centralized migration of the dispersed phase of the hydraulic mixture flow is formulated, describing the effect of turbulent mixing of the flow on the behavior of solid particles. An assessment of the secondary dispersion of the solid fraction of the hydraulic mixture, which causes a change in the consistency of the flow, was performed. The studies of the influence of the coefficient of consistency of the flow revealed that overgrinding of the fractions of the filler of the hydraulic mixture contributes to an increase in the required pressure in the pipeline system.

The petrogenesis and evolution of metamorphic rocks of the volcano-plutonic units of the Kaskama block of the Inari Terrane in northwestern Russia were studied. A petrographic and mineral study and modeling of igneous and metamorphic mineral formation were performed. PT-conditions of rocks, along with previously known data, including geochronological ones, do not allow us to correlate the studied units with rocks of the Belomorian complex, as previously thought. Modeling of igneous and metamorphic mineral shows good convergence with the fields of stability of mineral parageneses and quantitive ratio of minerals with those observed in the real samples. The early mineral parageneses of the magmatic stage corresponds to the crystallization of rock-forming and accessory minerals from the komatiite melt, and mineral parageneses of progressive and regressive metamorphism stages are superimposed on them. Relic igneous minerals (olivine, clinopyroxene, orthopyroxene, magnetite-spinel) in metaperidotites make it possible to estimate their liquidus temperatures in the range of 1,480-950 °С. The progressive stage of metamorphism is characterized by the development of mineral parageneses: garnet + amphibole + plagioclase + quartz ± biotite, amphibole + plagioclase + quartz. The late low-temperature regressive stage of metamorphism is characterized by the development of epidote-, zoisite-, actinolite-containing associations and a number of other low-temperature minerals. Peak parameters of progressive metamorphism are estimated as Т = 600-700 °С, Р = 5-9 kbar and for the regressive stage as Т = 400-500 °С, Р = 3-5 kbar. The identified thermodynamic conditions for the Kaskama block should be considered when determining whether the studied volcano-plutonic and metasedimentary units belong to the Paleoproterozoic terranes of the Kola-Norwegian Region of the Fennoscandian Shield.

For more than 50 years, most rare earth elements were extracted from carbonatite deposits, which can contain different rare earth phases, but the main extracted minerals are bastnaesite, monazite and xenotime. Many studies focused on the improvement and development of dressing circuits for ores of these minerals. However, in some carbonatite complexes, rare earth deposits are composed partly or mainly of ancylite ores. This type of rare earth ores was very poorly studied in terms of dressability – previous experiments with ancylite ores are rare and not productive enough. Ancylite is the main concentrator of rare earth elements in most carbonatite complexes of the Devonian Kola Alkaline Province (northwest Russia). Dressability of ancylite ore from the Petyayan-Vara carbonatite field in the Vuorijärvi alkaline-ultramafic complex was assessed using the flotation method. The complex is one of the most potential rare earth deposits associated with carbonatites in the Kola Region. Petrographic and mineralogical studies demonstrated the occurrence of abundant iron and barite oxide inclusions in ancylite, which imposes restrictions on physical separation of these three minerals. The study of petrogeochemical and mineralogical composition of fractions formed during mechanical grinding of ores to a size less than 2.0 mm showed that even at this stage of sample preparation, the finest-grained fractions (less than 0.071 mm) were enriched in ancylite (to 19 vol.% or more with a content of 15 vol.% in ore). Three classes of reagents were considered as collectors in flotation experiments: fatty acids, alkyl hydroxamic acids, and amino acid derivatives. The reagent from the amino acid derivative class was highly efficient. The use of such a collector in combination with sodium hexametaphosphate depressant made it possible to obtain a flotation concentrate in an open circuit with total rare earth oxides content 33.4 wt.% at 64.7 % extraction.

The subsurface state is explored and analysed by studying the core material. This is the basis for forecasts, construction and improvement of models. The reservoir properties of rocks obtained from the laboratory study of sample are subject to a system error caused by three main factors: rock selection in the zone of altered stress-strain state, rock removal from the thermobaric conditions of natural occurrence, and the measuring equipment error. A change in the natural stress-strain state of rocks occurs as a result of intervention in the formation system and the entire massif by constructing a well, creating overburden and depression. The rise of the core causes unloading from formation pressure to atmospheric one, natural saturation is lost, temperature conditions change. This affects the reservoir properties and rock injectivity. This study is aimed at investigating changes in the void space of the rock in formation conditions under cyclic loading. Based on the data obtained, a regression forecast of properties is made, excluding external influences. The article describes the results of experiments on multiple loading and unloading of water-saturated sandstone samples by geostatic pressure with precise control of the water displaced and returned to the void space. This method enables us to record the change in the internal void volume of the rock and, as a consequence, elastic and plastic deformations, the value of relaxation of elastic deformations. The dynamics of change in the coefficients of porosity and compressibility from the stress state cycle is estimated and the range of predicted porosity values ​​of the rock in formation conditions is determined. For samples of permeable medium- to fine-grained sandstone, the obtained character of porosity change gives a forecast of the initial porosity in formation conditions of 20.19±0.61 %. Thus, the exclusion of human impact on porosity gives values ​​1.42 % higher than the results of standard laboratory studies.

A new approach to determining the yield of volatile substances from coals in relation to explosion safety, including expert work in emergency mines during explosions, is considered. The results are based on complex experiments, including explosive tests and thermogravimetric studies of gases of various stages of metamorphism: from long-flame (grade D) to coking (grade K). Thermogravimetric studies were supplemented by explosive experiments in a 20-liter chamber, and more than 60 dust samples from emergency mine sites were also studied. Refined “stage-by-stage” indicators of the yield of volatile substances for solving dust explosion problems, which have significant advantages over the standard method of quasi-isothermal heating of dust in a muffle furnace, have been proposed and practically worked out. Methods of thermogravimetric determination of moisture and ash content of samples, as well as the yield of volatile substances at various stages of heating, with separation of the yield of combustible and non-combustible gases, have been developed. Non-overlapping intervals of the thermal reaction are identified: moisture yield (25-130 °C); heat-resistant heating (180-350 °C); primary yield of volatile substances PVS (350-600 °C); secondary yield of volatile substances SVS (600-750 °C); thermal degradation of mineral inclusions and inert dust CDS (750-840 °C). For emergency conditions, the stages of steady decrease and growth of the yield of volatile substances from post-explosive samples are determined and a criterion for the participation of coal dust in the explosion is formulated. The modified criterion makes it possible to numerically recognize the fact of dust participation in an explosion, determine the epicenter of deflagration combustion, and study the dynamics of the explosion over a mining network while determining the effectiveness of dust and explosion protection.

The article presents the first data on the rare element contents in the compositions of spodumene from pegmatites of the Laghman granitoid complex in Eastern Afghanistan, the Kolatan, Digal, Gulsalak, and Tsamgal deposits. The analyses were performed by SIMS method. The paragenetic features of spodumene were determined. It is present in spodumene-microcline-albite, spodumene-albite, and spodumene-lepidolite-clevelandite pegmatites in amounts of 10-35 %. The crystals range in size from a few mm to 1.5-2 m, sometimes to 3 m long. The crystals are prismatic, board-shaped, and rectangular. The contents of minor and rare elements in spodumene vary significantly from the centre to the edge of the crystals. The increase in the contents of Li (36,571-51,040), Na (378-1542), Mn (103-2877), Ga (24.4-90.1), Sn (5.52-382), Ti (1.3-79.5), Zn (0.37-38.4) ppm is accompanied by a decrease in the concentrations of K (3.86-147), Ca (1.39-105), Mg (0.26-276), B (1.69-57.3), Cr (2.75-15.1), Cu (0.65-11.6), Cs (0.0-8.75), Be (0.03-9.54), Ta (0.03-2.09), Sr (0.03-3.09), V (0.07-3.11), Rb (0.02-1.56), Ba (0.03-3.17), Zr (0.01-1.6) ppm. The amount of Fe decreases from the centre to the edge, and Mn and Sn increase from the centre to the edge in all crystals. In the pinkish-violet zone of the crystal, Mn content is significantly higher than Cr and Fe. A positive correlation is observed between Li and Na, Mn, Fe, Ga, Sn, B, Cr, Ti, Be and a negative correlation with K, Cs, Ta, and Nb. Spodumene from the Dara-e-Pech deposit contains more gallium than from the Kolatan and Tsamgal deposits, which is of practical importance. Sharp boundaries between growth zones indicate a diffusion rate that was less than the rate of crystal growth that occurred in conditions of pegmatite melt crystallization. As a result of the exchange with the residual melt, insignificant post-crystallization diffusion and restoration of equilibrium between the crystal and the environment took place.

In autumn 2023, comprehensive geophysical surveys were conducted in the experimental section of the Shestakovka River basin (Central Yakutia) to identify structural features of the near-surface part of the geological section, in particular permafrost rocks and talik zones. The work objectives included ground penetrating radar (GPR) studies and electrical resistivity survey. Drilling and well temperature logging data were used in the interpretation. The work is relevant due to the importance of studying the processes occurring in the cryolithic zone due to global climate change, and the novelty lies in clarifying the structure of the study area. The average permittivity of rocks across the section on the right and left banks of the river is 15.5 and 6.9, respectively. The differences are due to moisture saturation and the degree of soil freezing. The depth of the talik base on the right bank of the river is from 2 to 14 m with an average value of 6.1 m. On the left bank of the river, it varies from 3 to 7.1 m with an average value of 4.2 m. According to electrical exploration, the medium is a four-layer section. The upper layer about 2 m thick is the most heterogeneous in electrical resistivity and corresponds to seasonally frozen soils. The base of the underlying talik on the geoelectric section is traced at a depth of 4 to 7 m, which is consistent with drilling and GPR data. The third high-resistivity layer corresponds to permafrost rocks. The electrical resistivity in them increases by an order of magnitude compared to the talik zone and is about 2000 Ohm·m against the background of 100-270 Ohm·m. The underlying lower layer is characterized by a decrease in electrical resistivity to 220 Ohm·m, which may be associated with a change in the lithological composition or with the groundwater circulation.

The study examines the relationship between the weakening factors of the potassium-magnesium salt massif in the Palashersky section of the Verkhnekamsk deposit – specifically, the content of clay material in the form of halopelitic interlayers and the impact of technogenic brines on the strength characteristics of rocks in the productive strata during backfilling operations in mined-out areas. The results of laboratory studies on the influence of insoluble residue content and moisture on the strength properties of salt rocks are presented. Dependencies of changes in strength, moisture, and ultimate deformations on the duration of exposure to brines were established. Based on the test results, it was found that saturated brine does not significantly affect the compressive strength of sylvinite and rock salt but influences the intensity of deformability.

The demand for feldspar as a raw material in the ceramic industry is continuously increasing. Feldspar is abundant in the Earth's crust and typically found alongside other silicate minerals, as well as titanium and iron oxides. This study aims to reduce the iron oxide content in feldspar ore from the Wadi Zirib region and achieve an optimal grade of feldspar concentrate for various industrial uses. The research involved dry and wet magnetic separation techniques followed by leaching with oxalic and citric acids to minimize iron impurities and enhance optical properties. The factors affecting the dry magnetic separation, for feldspar size of –250+45 µm, were optimized using the Box – Behnken factorial design and a non-magnetic concentrate with 0.29 % Fe2O3 and an 92.19 % feldspar yield was obtained. The wet magnetic separation for feldspar fines of size –45 µm was optimized and a concentrate with 0.27 % Fe2O3 was achieved. The acid leaching was conducted on the non-magnetic feldspar concentrates using oxalic and citric acid. Oxalic acid was more successful in reducing iron oxide of dry (to 0.19 %) and wet (to 0.12 %) non-magnetic feldspar concentrates. The optical properties of the leached concentrates were improved compared to the original sample, as the whiteness improved up to 90 %.

Mineralogical-geochemical (SIMS method) study of titanite and geochronological (ID-TIMS method) study of garnets from mineral mines of the Southern Urals has been carried out. The mineral associations containing titanite belong to four contrasting types: epidote-titanite-garnet (Akhmatovskaya mine); garnet-titanite-diopside (Akhmatovskaya mine); epidote-titanite-chlorite (Nikolaje-Maksimilianovskaya mine); chlorite-titanite-garnet (Praskovie-Evgenyevskaya mine). Titanite from mineral aggregates of the Akhmatovskaya mine is enriched with LREE and Th, Nikolaje-Maksimilianovskaya mine – with HREE, Hf and Ta, Praskovie-Evgenyevskaya mine – with V, Cr, and Sr. It was found that the distribution of trace and rare-earth elements in titanite is related both to the composition of paragenetic minerals (garnet and epidote, Akhmatovskaya and Nikolaje-Maksimilianovskaya mines) and to the influence of rock-forming minerals of the parent rock – gabbro (plagioclase and pyroxene, Praskovie-Evgenyevskaya mine). The age of garnets (504.1±4 Ma) determined by ID-TIMS method from silicate-carbonate rocks of the Perovskitovaya mine does not agree with the ideas about the formation of the latter as a result of contact metasomatosis synchronous with the introduction of gabbroids or granitoids of the Kusa-Kopan complex (1,390-1,350 Ma), but does not exclude the influence of superimposed contact metasomatosis associated with late endogenous processes.

The problem of pollution of natural water objects with heavy metals is extremely relevant for the areas where industrial enterprises are located. Unauthorized discharge of contaminated wastewater, inefficient operation of sewage treatment plants, as well as leakage of drainage waters from man-made massifs lead to changes in the hydrological system affecting living objects. The article studies the composition of ash from the combustion of alternative fuels from municipal waste, and also considers the possibility of using it to neutralize sulfuric acid drainage waters and extract metal ions (Cu, Cd, Fe, Mn, Zn) from them. It has been established that the efficiency of water purification from metals depends on the pH value achieved during the purification process. The pH value is regulated by the dose of the introduced ash, the contact time and depends on the initial concentration of metal ions and sulfates in the solution. Studies on the neutralization and purification of a model solution of sulfuric acid drainage waters of a tailings farm of known composition have shown that in order to achieve a pH of 8-9, optimal for precipitation of metal hydroxides Cu, Cd, Fe, Mn, Zn and Al washed out of ash, and water purification with an efficiency of 96.60 to 99.99 %, it is necessary to add 15 g/l of ash and stir the suspension continuously for 35 minutes. It was revealed that exposure to ash with sulfuric acid waters leads to the transition of water-soluble forms of metals into insoluble ones and their “cementation” with calcium sulfate. The amount of Zn and Fe ions washed out of the ash decreases by 82 and 77 %, Al, Cd, Cu, Mn – by 25 %. This reduces the toxicity of ash, which is proved by a decrease in the toxic multiplicity of dilution of the water extract by 14 times.