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The method of high-performance sequencing using the Illumina technology investigated the diversity of prokaryotes in three soil samples (Technosols) selected on the territory of the former tailings of liquid waste of chemical production near the city of Kirovo-Chepetsk, Kirov region. The assessment of the taxonomic richness and phylogenetic diversity of microbial communities formed in the process of regenerative succession of the technogenic landscape, in comparison with the alluvial soil (Fluvisols) - a natural analogue of the one that was disturbed as a result of the disposal of waste from a chemical enterprise. The analysis of the indicators of taxonomic richness and diversity demonstrated their lower values in the soils formed on waste in comparison with the natural soil of the background site. 26 bacterial and 2 archaeal phyla of prokaryotes were identified, accounting for more than 95 % of the number of classified sequences. The phylum Actinobacteria (22-41 %) and Proteobacteria -20-26 %) dominated. At the level of higher taxa in disturbed soils, compared with the community of natural alluvial soil, trends in the representation of phylum were revealed: a decrease in the proportion of Verrucomicrobia and an increase in the proportion of Cyanobacteria. The greatest differences between the communities of technosols and background soil were revealed at the levels of orders, families and genera. Common and unique genera have been identified for each of the four microbiomes. The detected differences in the composition and structure of the prokaryotic component of microbial communities of disturbed soils are related to the complex of their physical-chemical properties (granulometric composition, pH of soil solution, C_org content, composition of toxicants of industrial origin, humidity regime, etc.) and the nature of vegetation cover. The results obtained are of interest for the development of new approaches in future studies of the relationship of soil microbiota with ecosystem changes caused by human activity.

Movements and deformations of ground surface at the Almaz-Zhemchuzhina deposit are studied using surveying techniques. The source data in estimation of parameters and patterns of the stress-strain behavior were observations over the modern geodynamic movements using survey markers and GPS / GLONASS technologies. The proposed scientific approach and guidelines on the use of the studies of trend and cycling geodynamic movements made it possible to determine the natural stress-strain parameters and to accomplish zoning of the test area by the intensities of the movements.

The spontaneous high-temperature conditions in deep mining cause significant changes in one of the factors that determine the risk of rock burst in coal mine roadways. Therefore, based on the test method of the bursting proneness of coal, uniaxial loading tests were conducted on coal specimens under different thermal loads to explore the variations in the bursting proneness and energy release of heated coal, analyze the variations and mechanism controlling the coal skeleton, physicochemical properties, quality, fracture mode evolution, and macrocrack quantity with different loading rates, and calculate and discuss the changes in the critical conditions of a coal-rock system during heating. In summаry, the study of the change in bursting energy release caused by the heating of coal can lay the foundation for the engineering-based prevention and control of composite dynamic disasters in deep coal mines.

The energy absorption buffer test system is developed, the impact load compression test of single free face coal sample is carried out, and the digital speckle analysis technology is used to obtain the law of the influence of the hole rate, which is the volume of the borehole divided by the volume of the coal sample, on the energy absorption rate and deformation and failure characteristics of coal sample after drilling. The change of the drill layout of two and three holes in coal samples has little effect on the energy absorption performance. The complete coal sample is easy to form vertical main cracks, and the drilled coal sample first forms stress concentration near the borehole, and a large number of cracks appear. The multihole coal samples are easy to form cracks that make the boreholes connected, which converts more impact energy into surface energy and improves the energy absorption rate of coal samples.

The authors put forward a look-ahead concept of science-based problem solving in deep-level mining. The issues of the problem realization and tooling are also addressed. A borehole charge is designed as a cluster of closed-spaced borehole charges to produce the directed blast effect by varying the cluster charge layout in a wide range. Using alternative technical capabilities of drilling, it is possible to variously redisperse the same equivalent energy in the single large-diameter borehole charge and in the cluster of smaller diameter borehole charges. The blast mechanism of the cluster charge pushes the limits of its application range and offers new approaches to problem solving in deep-level mining. Some technological aspects of geotechnologies are presented through the results of modeling the new approach to blast-induced impact using smooth particle hydrodynamics. Some tentative research findings inspire continuing with the study.

This study proposes a mathematical fracture model including processes of fracture of structural bonds on micro scale (tens microns) and meso scale (millimeters and centimeters), as well as interaction of structural fragments on macro scale (fractures longer then tens centimeters). The model uses two geometrical criteria of fracture growth, connected with the structure of rocks and governing transition between structural scale. The problem on the stress-strain behavior of an elastic medium near a fracture at the change in the fracture length and in the scale of its influence is solved. The limit equilibrium of a fracture is analyzed. For a meso-scale fracture, such condition is unstable, and the fracture, therefore, develops dynamically and up to a macro scale. Sufficiently long macro fractures can grow in the mode of quasi statics due to independent advance of fracture tips.

To reduce intensity of deformation in rocks prone to buckling and plastic deformation, and sensitive to geo- and gas-dynamic phenomena, the authors propose a consolidated backfill technology using salt waste and processing reuse brine at the consumption limits of water-yielding capacity. A set of laboratory tests is carried out to find backfill mixtures adaptable to deep-level potash mining with estimation of deformation characteristics and strength properties of potash salt rocks. New principles and technologies of deep-level sylvinite extraction and backfill material transport by creating such geotechnical structures in stopes which ensure formation of consolidated backfill mass with the mined-out stope space factor close to one. This approach can enhance mine efficiency owing to increased extraction of sylvinite from rib and safety pillars.

This article uses XGBoost algorithm to calculate rock in-situ stress. By using Pearson correlation coefficient method, it is determined that the logging parameters with the best correlation with minimum horizontal principal stress are Depth, GR, LLD, ILD, AC, VCA, with maximum horizontal principal stress are: Depth, GR, SP, CAL, DEN. In order to verify the performance of the model, linear regression, support vector machine, and random forest models are used for comparison. In order to improve the generalization performance, the k-fold cross-validation method is used. The results show that using XGBoost algorithm to predict rock in-situ stress with a small amount of data has a high average accuracy of 94% and good generalization performance. The linear regression model has a faster fitting speed, but the fitting accuracy is the lowest. The random forest and support vector machine models are in-between. The result confirms that the research method in this article has certain universality and can be extended to solve other rock in-situ stress prediction problems.

The article provides original information about relict phenomena in the structure of the forest component of the mountain forest-steppe of Southern Siberia (SS). Larch (Siberian larch ( Larix sibirica Ledeb.)) shrub-grass forests are characteristic element of vegetation in the forest-steppe of the SS. The oldest are the Pliocene, the most thermophilic analogues of the modern forest-steppe, noted in the foothills of the Western Tannu-Ola ridge (Horlety) is a small-leaved larch, dwarf-gmelin wormwood with participation in the community of mountain-Asian elements of ancient Middle-earth. It is important to note that in the species composition of the relict larch forest, the role of characteristic boreal species such as spirea ( Spiraea media Schmidt), prickly wild rose ( Rosa acicularis Lindl.) is insignificant in comparison with typical elements of semiarid florocenotypes of the Ancient Middle Earth. Among them, participation in the shrub layer of the small-leaved honeysuckle community, an element of the Altai-Dzhungar-Tien Shan relict florocenotype of highland Asian shrubs, is especially significant in phylogenetic terms. In the conditions of Western Transbaikalia, in the spurs of the ridge Malyi Khamar-Daban (Inzagatuy tract) describes the relict larch forest with the participation of characteristic species of the periglacial Pleistocene complex. In the Quaternary period - especially the xerothermic phases of the Holocene, as mountains deglaciate and a relatively warm and temperate climate develops, conditions are created for the formation of a modern mountain forest-steppe in the conditions of the semi-humid climatic regime of the SS. For example, forb-iris-sedge larch, characterized by a rich species composition of herbaceous plants, along with a well-developed undergrowth. This is expressed in the processes of mesoxerophytization of vegetation with the development of floristic complexes of meadow steppes and hemiboreal forests in the structure of phytocoenocomplexes of mountain exposure forest-steppe from Altai to Transbaikalia.

The article deals with the issues of artificial reforestation on the burnt areas in the permafrost zone of East Siberia (Yakutia). Scientifically substantiated work on forest plantations in Yakutia has not been carried out before this work. The results of long-term observations of larch crops, which were carried out on the territory of the Megino-Kangalassky forestry of the Republic of Sakha (Yakutia), are summed up. Artificial reforestation was carried out with of Kayander larch ( Larix cajanderi Mayr) seedlings. The article also presents and analyzes all the experiences of creating forest plantations recorded in various sources, carried out in the republic in different years. An analysis of the growth and development of larch plantation is given, an estimate of survival rate for 8 years is given. In the first years after planting, seedlings adapt to new environmental conditions, starting from the third or fourth year after planting, there is an increasing growth of seedlings, and from 15-20 years, the growth of larch crops is intensified. The characteristics of the vegetation in the area of artificial reforestation and in the control are given. For twenty years, significant changes in the vegetation cover have been traced: from meadow-forb to forest vegetation. The materials of the article can be the basis for the development of the most promising technologies for reforestation in the permafrost zone and will make it possible to achieve high-quality reforestation during artificial and combined reforestation in the light of recent changes in forest legislation.