The study of long-term climatic changes is carried out based on the data of the normalized relative vegetation index NDVI, which is a characteristic of phytobiomass and is used to describe the ecological situation, the amount of contamination and productivity of land. This theoretical work is based on the statistical and mathematical processing of MODIS satellite data (EOS Terra, Aqua), with the help of which the temporal and spatial variations of the NDVI vegetation index for the southern regions of the Russian Federation are studied. Several regions were selected, which located in mountainous or foothill areas on the territory of the North Ossetia-Alania, located in the central part of the North Caucasus. For each region, 20-year data series were obtained, each point of which is the NDVI index averaged over two weeks. With the help of these data series, the annual behavior of the NDVI index and its long-term variation are investigated, which shows the shift of a favorable growing season to an earlier period of the year. The annual integral characteristic of the NDVI index was used, which characterizes the long-term changes in the vegetation index in the studied regions. A statistical analysis of the series of integral characteristics was carried out, the parameters of linear regression were determined. The behavior of these characteristics for the foothill and lowland regions of North Ossetia-Alania indicates the presence of long-term trends in the changing conditions of the growing season.
For the southern regions of the Russian Federation, observational data show a relationship between trends in NDVI changes with a long-term improvement in climatic conditions for plant vegetation and changes in conditions during cold periods of the year. This factor should be taken into account in economic activities in the southern regions of the Russian Federation.
The results of chemical analyses of the waters of the transboundary Pyanj river tributaries – Gunt, Shakhdara, Bartang, Yazgulem and Vanch rivers are presented. The absence of stationary sources of pollution in the river basins and the dominance of rock weathering in the formation of hydrochemistry of the studied tributaries of the transboundary Pyanj River were established.
In this study, we use Sentinel 2 satellite imagery and GIS technology to evaluate the dynamic of land cover around Tan Rai bauxite mining area, Lam Dong province (Central highland of Vietnam). 02 Sentinel 2 images taken on November 15, 2015 and December 3, 2020 with spatial resolution 10 m (band 2, 3, 4, 8) were used to classify the land cover using object-oriented classification method. The results of land cover classification are used for creating the land cover status maps from 2015, 2020, and then for mapping the land cover change in the period 2015 - 2020. The results obtained showed that there was a significant decrease in forest area, both dense forest and mixed forest, plantation forest. Meanwhile, the area of agricultural land and industrial crop land increased by about 10% in the period 2015 – 2020. The area of Tan Rai aluminum mining project in 2020 also increased to 376.47 hectares, nearly 2 times higher than 2015.
The article is devoted to the technogenic triggering of the hazardous dynamic development of the landslide massif, which poses a threat of blocking the Khanikomdon stream with partial restrictions in the movement of residents of the mountain village of Dzuarikau. One of the main reasons for the intensive development of landslides in the Northern and Southern Jurassic shale depressions is the technogenic undercutting of slopes, caused mainly by the need of development of the mining industry or transport communications, although scientifically grounded pre-design solutions for minimizing the development of landslide processes can significantly reduce negative geoecological loads on the territory, which is especially important for the sustainable development of the mountainous areas. The aim of the work was to study the state of the landslide with modern measuring systems. Geophysical surveys were carried out by methods of vertical electrical and location-based sounding; the measurements of landslide movement were also carried out in the monitoring mode using surveys with a total station and a global positioning system GPS/GLONASS. The obtained results characterize a three-layer section of the “K” type with the thickness of a landslide high-resistivity massif of 18-21 m of crushed-loamy and gravelly composition, which is overlaid and underlain by more conductive clay strata. Geodetic observations show that the landslide body has moved throughout the entire monitoring period, but the velocities varied depending on the season. It is assumed that the seasonal variability in velocities is caused by the groundwater levels and associated pore pressures, which decrease when surface water is absent or cannot penetrate frozen landslide material, and increase when surface water from melting snow or rain penetrates the unfrozen landslide material.
The practical development of the algorithm for optimal control of mine ventilation was preceded by comprehensive studies of the specific features of mining sites in order to obtain their mathematical description. The latter includes the static and dynamic characteristics of objects, i.e. the relationship between input and output values.
The purpose of the research: to develop methods and management tools aerogasdynamics processes on mining sites of coalmines.
Research methods. The methodology based on the system approach; modern methods of mathematical statistics, decision theory; mathematical logic devices; factor analysis; mathematical modeling; set theory and system analysis.
To determine the dynamic characteristics of aerogasodynamic processes, experimental methods were used, divided into active and passive. The active method consists in con-structing a dynamic model of airing objects by approximating the transition curve obtained because of special effects on the airing object with an analytical expression. Statistical dynamics methods were used to obtain dynamic characteristics based on normal operation data. The method of correlation analysis was used.
Results of research: experimental verification showed that the maximum relative error of in determining the methane concentration from the static characteristic constructed using a modified technique does not exceed 10 %.
The value of the error was determined by comparing the static characteristic obtained by the modified correlation analysis method with the exact static characteristic of the airing object. The latter were found with regard to dynamic properties of the object and additive structures aerogas dynamics processes.
Conclusion. The method of correlation analysis can be used to determine the dependence of the methane flow rate on the airflow rate in the steady-state mode, i.e. the static characteristic q = f (Q) for the site and lava. To determine the static characteristics based on the data of normal operation with a limited observation interval (5-10 days), a modified method of correlation analysis is proposed.
Small values of the relative error of indicate the possibility and feasibility of using a modified correlation analysis technique to construct a static characteristic of the airing object based on random processes of methane concentration and air flow obtained during normal operation of the site.
The static characteristics C= f (Q) and q= f(Q) are widely used to determine the mathematical expectations of the methane concentration and flow rate of mining sites, in the modeling of ventilation facilities and in the analysis and synthesis of mine ventilation control systems.
Increasing the economic efficiency of enrichment of refractory gold-bearing ores is possible by reducing the cost of opening sulphide gold-bearing concentrates by reducing the yield of flotation concentrate sent to pyro- or hydrometallurgical processing. It is important to maintain the achieved level of gold recovery into concentrate with a lower concentrate yield. In order to achieve this goal, the gold content in the main flotation operation is increased by mixing the rough concentrate separated from ½ part of the ore feed with another ½ part of it. Mixing in the flotation operation of products with a high level of wash ability (ability to separate) – initial feed and rough concentrate – is identical to an increase in the content of the extractable component in the original ore.
In accordance with the new regime of flotation, the process is carried out in cold slurry with bubbles filled with hot steam. The physical basis of the new flotation regime is the dependence of the surface properties of air bubbles and surface forces that determine the stability of the liquid film separating the bubble and the particle on the temperature, which increases due to the heat of the vapor-liquid phase transition. Radial oscillations of the bubble surface as a result of pressure pulsations during condensation and vapor evaporation and surface thermal flows of liquid in the wetting film are factors that provide an increase in the completeness of gold recovery and the selectivity of flotation adhesion obtained in ore flotation experiments.
In laboratory conditions, a comparison was made of the indicators obtained during the dressing of gold-bearing ores according to the factory and new schemes. It was revealed that the use of the developed technology allows, with a lower concentrate yield, to obtain an increase of 7.06% abs. extraction of gold into a concentrate of the best quality. A decrease in gold losses with flotation tailings is a consequence of an increase in the number of particles reaching the bubble surface due to radial oscillations of its surface and a weakening of the stability of the wetting film by the thermo-capillary mechanism. An increase in adhesion selectivity can be interpreted using the concept of surface forces of structural origin – an increase in the forces of hydrophobic attraction and hydrophilic repulsion with increasing temperature. The interaction of vapor bubbles with nanobubbles on the surface of the solid phase (wetting by the Cassie-Baxter mechanism) ensures efficient particle recovery by the coalescence mechanism of flotation.
As a result of the identification based on the Hammerstein model of objects of the first stage of iron ore magnetic separation, the adequacy of the model is obtained. All results of the testing of the developed identification algorithms show that the subsystem of identification of the automated process control systems of processing plants based on the Hammerstein hybrid model allows to carry out satisfactory identification of objects and, as a consequence, to improve the quality of technological processes. The study of the influence of the coefficient of various typical links on the results of identification using orthogonal parallel and parallel-recursive Hammerstein models showed that these models allow considering the differences in the properties of identifiable objects adequately.
Goal. Substantiation of the ecological and economic efficiency of innovative technologies for the development of deposits of the Sadonsky ore cluster during the period of restoration of the lost industrial potential of the depressed region.
Methods. Analysis of the theory and practice of mining, with priority given to the experience in the development of North Caucasian deposits. Laboratory experiment in the study of the properties of filling mixtures and options with different activation methods, including reagent leaching in a disintegrator. Mathematical and economic modeling of the efficiency of recycling tailings utilization at the cost of commercial products, taking into account the prevented environmental damage.
Results. The information on the dynamics of mining and processing of ores from the Sadonsky deposits is presented. The results of studies of the properties of base concrete mixtures based on ore dressing tailings and local available components are systematized and generalized. The results of changes in the properties of hardening mixtures are given depending on the presence of metals in the tailings of enrichment with various activation options by alternative methods, including an innovative method of mechanochemical leaching in a disintegrator with electrochemically activated water. The equivalent of 1 kg of cement using binders from processing tailings has been determined. The advantages of mechanochemical activation of tailings in a disintegrator in comparison with the option of irrigation by irrigation using various reagents have been experimentally determined. A quantitative indicator of an increase in the strength of the compositions of hardening mixtures under equal conditions has been established. The efficiency of utilization of tailings and metallurgy has been determined as a set of effects of reducing the amount of environmental damage from storage of tailings, the cost of metals obtained during processing, raw materials for the construction industry and associated marketable products. The nomenclature of tailings processing products has been detailed. A model for determining the profit from processing tailings and metallurgy is recommended. A forecast is given at the level of engineering expertise of the prospects for tailings processing. The hardware diagram of the tailings disposal section is detailed. A universal scheme for the disposal of mining and processing waste was recommended.
Conclusion. The prospects for the development of the deposits of the Sadonsky ore cluster depend on conversion to technologies with filling voids with solidifying mixtures and leaching of metals at the processing stages. The combined mining technology will reduce the output of tailings, strengthen the base of the construction industry, eliminate the need to build a second stage of tailings and improve the environment.
The article discusses the creation, testing and implementation of new donor charges designed to initiate low-sensitivity explosives. The cast booster donor charges are made entirely of explosives obtained from the disposal of unnecessary ammunition – TNT, RDX and TEN. The donor charges differ from the mass-produced ones, and have a mass of 150 to 900 g. They also have high explosive characteristics: velocity of detonation from 7200 to 7500 m/s, density of 1.6 g/cm3, excellent water resistance and strength. Their initiating ability on low-sensitivity explosives is significantly better than the one of TNT presses. The velocity of detonation of the main charge of a low-sensitivity emulsion explosive initiated with a cast booster is up to 700 m/s higher than when initiated with a TNT presses. It is especially important when building objects in the constrained conditions, at development of mountain territories for decrease in action of shock air waves and elimination of possibility of mountain collapses and landslides In article advantage of use of cast intermediate detonators on safety of explosive works is proved at development of mountain territories. The new design allows an increase in the security of initiating the charges in the boreholes, which allows them to be initiated with two detonators simultaneously.
Introduction. Improving the performance, increasing productivity, reducing the metal consumption of grinding equipment and other mining machines is usually a very expensive process. It requires a large amount of development work, the production of prototype machines, and a large amount of experimental research. In this regard, one of the most important tasks is to simulate the movement of bulk material in operations for processing minerals in various equipment. In such modeling, the discrete element method (DEM) is widely used. The purpose of the research is to compare the models of the movement of the crushed material in the body of a vertical centrifugal mill.
Research methodology The motion of the bulk medium in a vertical centrifugal mill was modeled using two models. In the first model, the cylindrical body of the centrifugal mill was assumed to be stationary, and on its surface and on the entire surface of the rotor, conditions were set for the absence of a relative speed of movement of the crushed material. In the second model, a hydrodynamic model was used to describe the motion of a granular material as a viscous incompressible liquid with a compression ratio that depends on the pres-sure. In this model, the viscosity coefficient is represented as consisting of two terms: a constant (analogous to dynamic viscosity) and an excess pressure over hydrostatic pressure.
Research results It is established that both models give the same character of the movement of the material in the mill body. It is determined that the absolute velocity of the material movement near the walls and near the mill rotor is approximately the same for both models, but in the data obtained using the hydrodynamic model, as the material moves away from the walls and the rotor, it slows down more than for the model using the discrete element method. It is revealed that the absolute velocity of the material movement near the walls and at the axis of the mill rotor is approximately the same for both models, but in the data obtained using the hydrodynamic model, as it moves away from the walls and the rotor, the material slows down significantly more than for the model using the discrete element method.
Based on the simulation results, it can be concluded that for a more accurate simulation of the processes occurring during the rapid movement of bulk material in the grinding equipment, it is preferable to use a model using the discrete element method. It is advisable to use the hydrodynamic model for conducting a large number of search dawns or as a predicate model that will allow you to quickly set the initial velocity values for particles in a model using the discrete element method.
Conclusions 1. A hydrodynamic model of the motion of a bulk medium in a vertical centrifugal mill, represented as a viscous incompressible liquid with a compression coefficient depending on the pressure has been developed. 2. It is established that for a more correct simulation of the processes occurring during the rapid movement of bulk material in the grinding equipment, it is preferable to use a model using the discrete element method. At the same time, it is advisable to use the hydrodynamic model for conducting a large number of search calculations or as a predicate model that will allow you to quickly set the initial velocity values for particles in a model using the discrete element method.
ISSN 1998-4502 (Print) ISSN 2499-975Х (Online)