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We studied the communities of soil surface Coleoptera (Carabidae et Tenebrionidae) in the mountain hollows of Altai (Kurai and Chuya) and Tuva (Ulug-Khem and Ubsu-Nur; in the latter, the arid western sector and the more humid eastern sector were studied). Collections were made in the same habitats at intervals of about 60 years: in 1962-1963 and in 2018-2020. Climate changes over this period were analyzed. In general, the climate of the characterized steppe depressions retained the features of sharply continental, with negative mean annual temperatures, moisture deficit and high frequency of fluctuations of all parameters. In all regions an increase in average annual temperatures and in the last 10-20 years an increase in annual precipitation has been observed, most strongly in the Ulug-Khem hollow, creating preconditions for reduction of aridity of ecological conditions. Over 60 years, the number of beetles of the studied taxa has changed several times, sometimes by more than an order of magnitude. At the same time, the number of representatives of the more xerophilic Tenebrionidae family fell, while the number of the more mesophilic Carabidae increased. When comparing the proportion of tenebrionids in the population of different habitats in the 1960s with their proportion in 2018-2020, a sharp, several-fold decrease in their participation in the communities is observed in almost all cases. More beetle species with a more northern or broader (polyzonal and/or transpalaearctic) distribution are becoming more common in the Tuva basins. Such species are found in both humid and arid regions. These changes in species compositions and soil-dwelling beetle communities may reflect mitigating climatic conditions due to some increase in precipitation in the studied region. The mean values of the indices of species diversity and abundance do not differ in general for the “before” and “now” ecosystem states. There are also no reliable differences for total species richness and total abundance. But there are noticeable interannual differences for some diversity indices calculated for Altai ecosystems in 2018 and 2020. This may indicate that differences between the overall diversity indices of ground beetle communities in dry and wet years overlap the long-term trend caused by climate change, and populations of species with different life strategies in the communities respond quickly to these changes without losing the overall structural complexity of the animal population.

Coregonus sardinella Valenciennes in the Khatanga River basin (Taymyr Peninsula) was considered as a component of ichthyocenosis and was never the subject of special study. As well-known published materials show, Coregonus sardinella in the Khatanga River basin are represented by semi-anadromous, lacustrine and lacustrine-river forms. In this work the features of the size and age structure characteristics, fecundity, migration and fishing in modern conditions of the semi-anadromous form of Coregonus sardinella are analyzed. During the study period (2010-2018) fish with a length of 186 to 364 mm and a mass of 54 to 442 g have been spotted in the spawning stock of semi-anadromous Coregonus sardinella in the Khatanga River basin; an average of 275 mm in length and 163 g in weight at the age of 5+ to 15+ years. Males slightly prevailed over females in numbers (57.3 and 42.7 % respectively). The individual absolute fecundity (IAF) has been shown to vary from 4.6 to 36.7 thousand of eggs, on average 13.4 thousand of eggs, during the period 2010-2018. Individual relative fecundity (IRF) varied from 37.5 to 172 pcs/g of body weight, on average 88.4 pcs/g. The boundaries of the main spawning grounds were clarified, which are located on the section of the Kheta River from its mouth to the mouth of the Boganida River (a tributary of the Kheta River, 414 km from the mouth) and the Khatanga River, 20 km from the confluence of the Kheta and Kotuy rivers.

The characteristics of mineral floatability, namely, the wetting angle and the induction time, are examined. The agreement between the predicted floatability using these characteristics and the theoretical and experimental data is accessed. It is found that hydrophobicity defined by the wetting angle is not always a quantitative characteristic of floatation. The floatability predicted using the time of induction and mechanism of physisorption of collecting agents agrees with the tests and actual practice. The successive change in floatability of sulfhydryl and oxyhydryl collectors in transition between different reagents disagrees with the estimate of the collector force determined from the binding energy between the functional group of a collector and the cation of mineral surface. The force estimated as the effect of a physisorbed collector on the water interlayer between bubble and particle adequately describes floatability of minerals. The mechanism of physisorption of a collector is universal relative to different reagents, is applicable to the description of particle-bubble interaction and enables selecting the structure and composition of radical on an effective collecting agent.

The article describes the method of potentiometry in determination of characteristic diameters of air bubbles. The authors discuss feasibility of the Sauer diameter measurement of air bubbles using the difference of electrode potentials at different depths in flotation machine and with further evaluation of aeration intensity. The studies involved a two-phase system at different consumptions of air and frother. The highest aeration intensity is found from the checking tests of a three-phase system. It is found that the rate of increase in the difference between the electrode potentials linearly correlates with the Sauter diameter of air bubbles.

The article discusses hydrochemical modification of properties of zeolite-bearing rocks in East Transbaikalia. It is found that acid-based modification enhances adsorbability of natural zeolites. The technology of processing with chemical modification is developed for zeolite-bearing rocks with regard to the earlier research findings on mineral treatment by ultrasound, accelerated electrons and high-power magnetic impulses. The rate of dealumination and the silicon module of natural zeolites from East Transbaikalia are correlated with the sulfuric acid concentration. The implemented computer-aided modeling of zeolite minerals is based on the quantum-chemical interaction of particles. The authors depict the range of use of the high-quality zeolite products in the technologies of mining waste management.

In this study, the thermal decomposition of zircon magnetic tailing has been conducted to remove phosphate using a roasting process with Na₂CO₃ and water leaching. The research on zircon magnetic tailing processing, which contained monazite, xenotime, zircon, anatase, rutile and cerianite, aimed to test the effectiveness of roasting techniques for phosphate decomposition so that REE can be easily extracted. The optimal conditions to ensure phosphate recovery up to 93.27% were determined. In this condition, zircon and xenotime minerals are still confirmed in the roasting products using Na₂CO₃.

The authors have developed a procedure for estimating recovery dynamics of natural ecosystems damaged by mineral mining using the satellite observation data. The procedure uses the vegetation index of phytocenosis and the temperature of underlying terrain. The case-study of apatite-bearing ore processing waste revealed the time series of the vegetation index and the underlying terrain temperature of the incipient phytocenosis as compared with the phytocenosis of the surrounding natural landscape. It is found that the recovery of the natural ecosystems by generation of a biologically active medium activate the test factors to reach the values of phytocenosis of the surrounding natural landscape. The justification is provided for usability of the retrospective earth remote sensing data on ground surface in the objective estimation of recovery dynamics of natural ecosystems damaged by mineral mining in the Arctic conditions without undertaking land exploration.

The article presents a case study of dust emissions from the preparatory works for the opening of the mine "Cukaru Peki" near Bor, Republic of Serbia, including an analysis of the total deposited materials, which illustrates the practical application of the proposed methodology. The monitoring was conducted one year before the start and from January to September 2018 during the preparatory mining works. The analysis of existing data predicts the creation of deposited substances from the atmosphere. This paper evaluates the validity of the Gaussian model for predicting the potential impact of dust deposits generated during preparatory mining works.

The authors propose and analyze the method of soft rock reinforcement by injection of bicomponent organomineral resin with compressed-air blowing of reagents deeper in rocks. The bench tester structure, the polymeric formula, the composition and resin properties, as well as the treatment procedure are presented. The tests are described. The scope of the discussion encompasses the results of the permeation tests, strength tests and the analysis of structure of voids in sand samples after their stabilization using the proposed approach and the standard single-component resin injection. The advantages of the successive injection include the chemical treatment coverage, specific consumption of agents and the increased strength.

The authors discuss the known methods of shaft lining monitoring and put forward a new technique of real-time measurement of displacements on inner surface of concrete lining by laser scanning. The results of the preliminary filtering and subsequent processing of the specific monitoring measurements implemented in two mine shafts of Uralkali are presented as the estimates of the change in the shaft diameter, circumferencial strains and ellipticity. The monitoring data are effectively applicable in verification of mathematical models of strains and strength of concrete lining in shafts, including their junctions with horizontal tunnels.