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Complex estimation of geotechnical risks in mine and underground construction

Elena Yu. Kulikova, Sergey V. Balovtsev, Olga V. Skopintseva

Introduction. Projects for the construction of underground structures and mines often involve significant geotechnical risks. The uncertainty associated with geotechnical conditions implies the development of a specific approach to making design and constructive decisions. Even after a thorough geotechnical study, the ability to accurately predict the behavior of adjacent rock massif is often difficult due to the large number of engineering-geological and hydro-geological variables. Most of the identified risks can be eliminated at the design stage. Residual risks should be subjected to a comprehensive assessment, including qualitative and quantitative analysis and calculations of damage from potential risk and technical and economic efficiency of the adopted design decision. Objective. Complex estimation of geotechnical risks in mine and underground construction based on the analysis of indicators of the implementation of accidents by mining-geological and mining-technical factors, taking into account the use of special methods of construction. Methodology. A сomplex estimation of geotechnical risks was carried out on the basis of the theory of emergency risk using methods of mathematical statistics, probability theory; the method of expert assessments to obtain the values of vulnerability coefficients of the applied technologies of mine and underground construction. The developed methodology includes several stages. At the first stage of a сomplex risk estimation, it is necessary to rank the geotechnical risk factors selected for analysis, for which a concordance coefficient is introduced. When analyzing each of the emerging geotechnical figures during the construction of a specific underground or mine construction facility, one of the defining indicators is the numerical expression of the potential damage from the occurrence of an emergency situation, which represents the percentage ratio of the excess of the construction period in real practice to the same indicator laid down in the project, or the ratio of the increase in the cost of construction to the estimated cost. Next, the numerical value of each type of risk is determined and a scale of numerical values of risks is compiled, on the basis of which decisions are made on the management of each specific risk. At the end, the vulnerability of a mine or underground construction facility under construction is determined, i.e. the degree of its possible damage and destruction when exposed to abnormal situations of a natural and man-made nature. Results and discussion. A methodology has been developed for the сomplex estimation of geotechnical risk in mine and underground construction based on the ranking of risks according to the degree of vulnerability of the technologies used. Ranking of construction objects by their vulnerability to various impacts allows us to assess the correlation between the values of the parameters and the qualitative characteristics of the elements of the “mining – rock mass – construction technology” system and the factors that lead to the development of potential damage. In the course of the research, a generalized indicator of the predicted geotechnical risk was identified, which allows taking into account the impact of construction methods on the risk. Since mine workings are currently being built mainly in complex hydro-geological and engineering-geological conditions, the calculation of the generalized indicator focuses on the use of special construction methods, which required the introduction of correction factors to calculate the indicator of the predicted geotechnical risk. The values of correction coefficients for the most used special methods were obtained by the method of expert assessments. Conclusions. One of the important aspects of a сomplex estimation of geotechnical risks in mine and underground construction is to determine the vulnerability

Number of views: 131

Modeling of sustainable agricultural land use on the basis of agroecological assessment of the territory

Bolat Zh. Akhmetov, Assiya Zh. Kasenova, Oleg E. Merzlyakov, Leonid M. Tatarintsev

The purpose of the study: to create a model of sustainable agricultural land use on the example of an existing agricultural organization in the Altai Кrai based on a comprehensive agro-ecological analysis of the territory. Research methods: A systematic approach and its variation, agroecological analysis, has become the main method of this scientific research. Spatial studies were carried out using the cartographic method. The obtained sets of analytical data were processed using GIS technologies. We also used the method of scientific abstraction, methods of analysis and synthesis, induction and deduction. Research results. The area of the study area is more than 13.4 thousand hectares, among which arable land, hayfields and pastures predominate, which are everywhere to some extent subject to degradation processes. In general, the study area is typical for the subzone of the southern forest-steppe of the Altai Krai, so the results and models can be applied to the territories of the Russian Federation and the Republic of Kazakhstan that are similar in natural and economic terms. When analyzing the on-farm use of agricultural land, it was found that environmental stability depends on the degree of plowing, forest cover, the ratio of the main lands (arable land, meadow, forest plantations) and the calculated coefficients of environmental stability and anthropogenic load. It has been determined that the territory occupied by agricultural land and agricultural land is unstable and is subject to an average anthropogenic load. The author’s methodology for assessing the agro-ecological characteristics of agricultural lands used in the work made it possible to identify and typify the studied lands, compile unique digital maps of types of terrain, tracts, lands, and develop models for the transformation of agricultural lands, which made it possible to increase the sustainability of agricultural land use to a state of unstable stability. When modeling the landscape, the main task was to recreate the natural diversity and the mosaic pattern of land placement, which makes it possible to balance the material and energy processes occurring in the landscape. Conclusions: 1. An agroecological assessment of agricultural land of an agricultural organization in the Altai Krai was carried out. 2. Unique map-schemes of types of terrain, tracts, lands, study area were compiled, limiting factors and conditions affecting it were determined. 3. Modeled options for the transformation of agricultural landscapes, which contributed to a change in its sustainability, which is confirmed by the calculated indicators of the coefficients of environmental stability and anthropogenic load of the territory. 4. The results of the study can be applied in: organizing the territory of agricultural land use; designing land use systems; long-term planning and management of land resources, monitoring and cadastral valuation of land.

Number of views: 79

A regional criterion for classifying mining regions as territories with the greatest exposure to geoecological changes

Alexandra A. Kulikova, Tatyana I. Ovchinnikova

Introduction. Territories adjacent to mining regions always experience a negative impact from the mining enterprise. The scale of such an impact on the environment is estimated by taking into account factors such as geographical location, climatic conditions, the amount of minerals extracted, as well as the ratio of mineral reserves to the area of the mining region. For geo-ecological assessment of the scale of impacts of the territory near the mining region on the environment, it is necessary to introduce a regional coefficient that takes into account the quantitative distribution of mining enterprises on the area of the mining region, as well as the ratio of reserves to area. In this regard, the question arises about the creation of a geo-ecological assessment methodology based on this indicator. Objective. Development of a criterion for a comprehensive geo-ecological assessment of mining regions impact, based on the regional indicator on the example of coal mining enterprises. Methodology. When carrying out the research, the analysis of literary domestic and foreign sources was used; generally accepted methods, including methods of geo-ecological assessment, assessment of natural potential, analysis of anthropogenic load, protection of the territory of the location of the coal mining enterprise. Results and discussion. A functional scheme of the stages of the geoecological assessment of the territory of a coal mining enterprise has been developed to calculate the geoecological assessment indicator with regard to the natural potential of the territory, the total anthropogenic load and the protection of the territory. It is proposed to use a regional indicator to classify the mining region as the territories most susceptible to geoecological environmental changes due to the ratio of the amount of coal production and reserves to the area of the mining region and taking this coefficient into account when allocating state subsidies to improve the environmental situation of the mining region. Conclusions. The main criterion of the geoecological assessment of the mining region– the regional indicator of the attribution of the mining region to the territories with the greatest susceptibility to geoecological changes has been established. The criterion is estimated by the ratio of the volume of production and coal reserves to the area of the mining region. This coefficient is crucial when allocating state subsidies to improve the environmental situation of the mining region. The introduction of a regional indicator creates optimal conditions for forecasting geoecological hazards and the appointment of environmental and nature restoration measures.

Number of views: 90

On the issue of assessing the ecological condition of the environment to achieve sustainable development of coal-mining regions of Russia

Olga M. Zinovieva, Lyudmila A. Kolesnikova, Anna M. Merkulova, Natalya A. Smirnova

Introduction. In conditions when the environmental component acts as a priority direction for the development of regions, the assessment of the actual ecological condition of the environment is an important stage in the development and implementation of a sustainable development strategy. This is especially true for coal-mining regions, which are characterized by a significant negative impact on all components of the environment. Purpose of research. Conducting a comparative analysis of determining the level of environmental safety of the territory based on a comparison of its ecological capacity and the actual anthropogenic load of environmental components of coal-mining regions, as well as the methodology for assigning an ESG rating. Methodology. The research methodology is based on methods of analysis, synthesis, abstraction, deduction, etc. Results and discussion. An analysis of the Russian and international methodology for assessing the ecological state of territories shows that different approaches are used both in our country and abroad. In recent years, environmental assessment has also been carried out by rating agencies as part of the creation of an ESG rating of the regions of the Russian Federation. The study was conducted for the largest coal–mining subjects of the Russian Federation – the Kemerovo Region, the Krasnoyarsk Territory and the Republic of Khakassia. The assessment of the ecological condition of these regions was carried out in two ways. In accordance with the first approach, based on a comparison of the ecological capacity and the actual technogenic load of the territory, environmental safety in the Kemerovo region is assessed as an environmental disaster, in the Krasnoyarsk Territory – an environmental norm, in the Republic of Khakassia there is an environmental crisis. Despite the fact that according to the results obtained by the first approach, the Kemerovo Region is in an environmental disaster zone, according to the second approach, based on the formation of an ESG rating, it has the highest E-rating, while the Krasnoyarsk Territory and the Republic of Khakassia have a sufficient one. It should be noted that the E-rating does not take into account the ecological capacity of the territory and does not reflect the actual environmental burden in the region. According to the authors, in order to reflect the real ecological condition of the region, it is necessary not only to take into account the dynamics of environmental impact, but also to compare the level of this impact with the ecological capacity of the territory. Ratings developed for the purpose of ecooriented management of regions do not fully meet the existing situation in the regions due to a simplified scoring system. Conclusions. The assessment of the ecological condition of three large coal-mining regions by different approaches shows contradictory results. The necessity of developing a unified methodology for a Complex estimationof the ecological condition of the environment in the region, taking into account the actual state of the region, its ecological capacity and the work of authorities in the field of environmental protection, is shown.

Number of views: 73

Economic and legal issues of mineral deposits development

Igor A. Alekseev, Zarema M. Khasheva

The relevance of the work is explained by the need to increase the mineral raw materials extraction volume to meet the demands of industries. The purpose of the work. Formation of new relations in the field of extraction and processing of mineral resources, reducing the contradictions between technology, society and the environment. Materials and methods: systematization, generalization and analysis of theoretical studies using predictive methods. Results. A reference is given on the consumption of mineral resources and the formation of waste from the processing of raw materials. The features of the possession of minerals and the influence of this factor on the formation of world politics are characterized. The urgency of the problem of preserving the natural environment and rational use of subsurface reserves is substantiated. The growth rates of resource production up to 2025 are given. The main directions in the field of mineral resources development are formulated. The article describes an instrument for the implementation of state control over the protection of the subsoil, in which the preservation of the Earth’s surface and its restoration in case of violation by mining operations play a priority role. Recommended measures for rational and integrated use to prevent the loss of raw materials. A model of the economic efficiency of nature conservation according to the criterion improve environmental management. The expediency of cooperation between industrial enterprises in order to increase production efficiency through waste disposal is substantiated. It is shown that the future of mankind depends on the reasonable treatment of nature and the rational use of natural resources, and the efficiency of subsoil use is ensured by the solution of legal and economic problems. Resume. 1. The article substantiates the formation of new relations in the field of extraction and processing of mineral resources, reducing the contradictions among technology, society and the environment. 2. The results of the article can be in demand as an element of the methodology of educating a new attitude to nature which is a link in the system of overcoming antagonistic contradictions between technology and nature.

Number of views: 88

Mathematical modeling of the weak low-frequency impact of seismic waves on the glacial massif

Illarion D. Muzaev, Konstantin S. Kharebov, Nugzar I. Muzaev

Introduction. The Kolka glacial massif repeatedly broke off from the freezing surface and thereby formed powerful glacial mudflows that caused great material damage to the Republic of the Republic of Alania with numerous human casualties. In the work of Muzaev I. D. and Sozanov V. G., the first step was taken in mathematical modeling of seismic vibrations of the glacial massif and the statement was proved that weak earthquakes of 3-3.5 MSK points can provoke bending and shear stresses several times higher than the destructive stresses of ice on the underlying surface of the glacial massif. The considered mathematical model proposed in the article has been amended, significantly clarifying the scientific results. The purpose of the work is to formulate and solve an initial boundary value problem that resembles the problems of mathematical physics and simulates the fluctuations of a glacial massif. The oscillation of the array is caused by the freezing of a weak traveling harmonic seismic wave with an intensity of 3-3.5 MSK points falling on it and on its underlying surface. Materials and methods. Due to the fact that the longitudinal dimensions of glacial massifs are an order of magnitude larger than their transverse dimensions, the article assumes that the mechanics of such massifs are most adequately modeled if their geometric configurations are considered as girder bodies with their physical and mechanical characteristics. The losses of mechanical energy due to internal resistance in the array material are taken into account in accordance with the hypothesis of S. A. Sorokin. The elastic rebound force from a seismically oscillating base is taken into account in accordance with Winkler’s hypothesis. Due to the fact that the coefficient of the differential equation of vibrations of the beam array is complex, the equation splits into a system of two fourth-order differential equations with real coefficients, where the desired functions are the real and imaginary parts of the originally sought complex function. The initial boundary value problem is solved analytically. Results. On the example of the Kolka glacier (North Caucasus Highlands), which collapsed in 2002 and claimed 126 human lives, computer experiments were performed to calculate induced stresses. Discussion. Comparative computational experiments have proved the claims that the seismic stresses caused by the Winkler elastic rebuff of the seismically oscillating surface of the base: a) are significantly greater than the stresses from the bending component of the vibrations of the array; b) can significantly exceed all the values of the destructive stresses of the ice. Conclusion. It is proved that the superiority of the Winkler stress over the destructive stress of ice can also occur in weak earthquakes with an intensity of 3-3.5 MSK points. Such superiority can play the role of a trigger for the breakaway of the glacial massif from the freezing surface and thereby the formation of a powerful glacial mudflow, as happened on the Kolka glacier. Suggestions for practical application and directions for future research. The paper presents a method for directly determining the cause of the breakaway of the glacial massif from the freezing surface. In the future, it is desirable to check the effect of a sharp induced maximum stress for steels intended for mechanical engineering purposes. It is desirable to study in detail the time dependence of the effect of inducing maximum stresses in arrays using low-intensity waves.

Number of views: 87

Assessment of Ulaаnbaаtar sustainable development on the basis of soils geochemical analysis

Galina I. Sarapulova

Introduction. Assessment of the ecological state of mountainous areas and, especially, large cities, in particular the city of Ulaanbaatar, the study of anthropogenic pressure on sensitive mountain landscapes is very relevant. This is important from the point of view of the contribution of the ecological structural component to the sustainable development of the mountainous area. However, the lack of data on the spatial distribution of the microelement composition of the soil of the urbanized mountainous landscape, especially heavy metals, does not allow a Complex estimationof the ecological state of the territory of the mountainous capital of Mongolia. The purpose of the research: ecological assessment of the soil cover of the metropolis of Ulaanbaatar using geochemical parameters and GIS technologies. Materials and methods of research. Field and physico-chemical methods of studying soils, as well as GIS technologies were used to obtain halo maps of the distribution of anthropogenic pollutants - heavy metals Pb, Cu, Ni, Zn, Hg and oil products. Research results. It was revealed that the key parameter of the state of the soil, the pH indicator, reaches 8-9 units, which means alkalization of the surface soil layer. An active ion-exchange complex has been formed, which leads to the accumulation of technogenic pollutants in the soil. The contents of metals Pb, Cu, Ni, Zn, Hg exceed their standard values based on MPC (MAC). With the use of GIS, halos of their distribution, as well as oil products in the territory of Ulaanbaatar, were obtained. Discussion. Sources of heavy metals are emissions from thermal power plants operating on lignite. Yurts also contribute to severe soil pollution, as they are heated by coal stoves. A large number of personal vehicles and a chaotically located network of gas stations supply metals and petroleum products to the soil. The formation of sparingly soluble fixed forms of metals as a result of alkalization led to their accumulation in the soil. Linear local fields of metal pollution have been identified, which clearly indicate the ecological trouble in the city and the need to take environmental protection measures. Conclusion. The parameters of the geochemical state of techno-genically altered mountain soils in the city of Ulaanbaatar revealed contamination with heavy metals and NPs. Local pollution modules with the accumulation of chemical toxicants have been formed. The halo maps of their distribution are obtained, the formation of a spatially linear type of pollution of the mountain landscape is shown. Offers. The possibility of zoning the territory according to the degree of environmental safety is shown. This should <

Number of views: 77

Geo-mechanical prediction of the brittle fracture zones in rocks in the vicinity of the excavation junction of Ltd "Apatit" mines

Pavel A. Korchak, Maksim A. Karasev

Introduction. Prediction of excavations stability is an important step towards ensuring geo-mechanical safety during their construction. A reliable prediction of the stability of excavations includes such factors as the initial stress state, physical and mechanical characteristics of rocks, rock mass fracturing, and a number of others. These factors should be considered when performing calculations. The geo-mechanical conditions of the Apatite deposits are different, rock pressure can manifest itself in the form of brittle fracture of rocks, limited displacement of the rock contour, the formation of local rock failures or arching. In this paper, we consider only areas of the rock mass, where the loss of stability of the excavation contour is associated with the formation of brittle fracture zones. An analysis of methods for predicting brittle fracture zones suggests that they are devoted to their formation in the vicinity of single excavation and do not consider the formation of brittle fracture zones in the areas of excavation junctions. Despite the fact that a significant number of research papers are devoted to the formation of plastic deformation zones and the assessment of the excavation contour stability, they mainly consider two forms of geo-mechanical processes - rock failure along fractures and rock contour deformations. At the same time, little attention is paid to the formation of brittle fracture zones in the areas of excavation junctions in rocks predisposed to the development of such geo-mechanical processes. Considering the conditions of the Apatite deposits, it can be noted that the values of deformational and strength characteristics of rocks are very high. The rock mass is different in fracturing characteristics, however, the volume of rocks with excavations, which can be classified as weakly fractured, is very significant. The initial stress state of rock mass is characterized by the tectonic nature, where the magnitudes of the largest horizontal stresses are several times greater than the vertical stress component. All this makes it possible to classify the conditions of Apatite deposits as very difficult and rock burst hazardous. Methods and materials. To assess the correctness of the numerical modeling using model of brittle fracture of rocks, the following typical problems are considered: forecasting the development of brittle fracture zones in the vicinity of excavations of research laboratory in Canada; forecast of zones of brittle fracture of rocks for mining-geological and geo-mechanical conditions of the Apatite enterprises. Numerical modeling and the stress-strain state prediction in the vicinity of excavations was carried out in a generalized plane-strain formulation (three-dimensional formulation with the assignment of appropriate boundary conditions). An analysis of numerical simulation results suggests that the increase in the size of the brittle fracture zone is that greater, the larger the junction span. This effect was obtained for all four variants of excavation junction. The following results of the stress-strain state formation in rock mass in the vicinity of excavation junctions were obtained: the size of the brittle fracture zone as a whole tends to increase in the areas of excavation junctions, while the type of junction plays a significant role in its size; the higher the value of the σmax index, the more clearly the influence of the junction type on the size of the brittle fracture zone is manifested, while at the ratio σmax/σc < 0.8, the difference in the sizes of the zones in the junction and the extended section of the excavation is not significant. It was noted that the excavation junction has an impact not only on the size of the brittle fracture zone, but also on the nature of this zone formation. There is a “flow” of the brittle fracture zone from the junction are

Number of views: 88

Development of a method and apparatus for measuring the forces in particle contacts under conditions of flotation of gold microdispersions

Sergey I. Evdokimov, Alla K. Makoeva, Ruslan N. Maksimov, Dar’ya I. Dyatlova

Introduction. In flotation of gold-containing ores, metal losses with tailings are mainly related to the fine particle size classes - micro dispersions. Study of the physical nature of the forces in the contacts between the particles, including gold micro dispersions, allows gaining new knowledge associated with the solution of the pressing problem of effective extraction of difficult to extract forms of the precious metal by flotation. Materials and methods. Measurement of the forces in contacts of particles was carried out by sediment volumetric method using the developed device. The method allows to determine the forces in contacts of particles by the volume of their sediment, formed as a result of kinetic destruction of the disperse system. Alluvial gold from the collection formed during the experimental tests of the equipment of separation complexes "Shlich", "Shlich-2", "PGShOK-50-2" was used in the experiments. The results of measuring the forces were supplemented by theoretical studies, which had the aim to estimate the contribution of the fluid volume held by capillary forces in contacts of particles to the volume of sediment. Results. It was found that the volume formed by the kinetic destruction of the disperse system is determined by the force in the contacts of particles, and the volume of capillary held liquid is of subordinate importance. Discussion. It is shown that the results obtained can be explained by involving the notions of boundary layers of fluids with a structure changed under the influence of surface forces. The low-entropic structure of liquid in the boundary layer of hydrophobic surface is caused by forces arising inside liquid itself near weakly interacting surface, and is energetically the least favorable, corresponding to the maximum of free energy. Therefore, the particles behave as if there are hydrophobic attraction forces among them. Conclusion. Uncompensated charges near hydrophilic surface create high-entropic structure of water with normal orientation of its dipoles and increased density, which causes the appearance of structural hydrophilic repulsive forces among particles. Resume. Structural hydrophobic attraction and hydrophilic repulsion are endothermic processes. Their violation will be an exothermic process and its exo-thermicity increases as the temperature rises. The developed method of flotation is based on this property of structural forces: the stability of wetting films in flotation processes of micro-dispersions of minerals is changed by heating water in the boundary layers of air bubbles - hydrophobic cavities in water - due to the condensation heat of hot water vapor. For this purpose, aeration of the flotation system is carried out by a mixture of air and steam. Proposals for practical application and direction of future research. Practical significance of the project is to develop technology for flotation of the most difficult to extract forms of gold. Its essence is based on the effect of preferential adhesion of gold micro-dispersions on its own hydrophobic large particles - a solid wall. Thin plates, flakes and sheets of native gold are used as it. The aggregates formed by the above described mechanisms from poly disperse particles are extracted by flotation. In case of extraction in several steps the rough concentrate can be used as a solid wall (carrier minerals). In further research it is necessary to develop an organizational mechanism of joint processing of ores and gold placers.

Number of views: 75

Peculiarities of poly disperse particle interaction in gold micro dispersions flotation processes

Tatyana E. Gerasimenko, Iya O. Rubayeva, Ruslan N. Maksimov, Vyacheslav V. Vasiliev

Introduction. In flotation of large particles, the approach of a particle to a bubble is provided by inertial forces, while in the case of small particles this process proceeds inertially. Inertia less hydrodynamic interaction with the bubble - movement with the liquid flow without contact with the surface of the bubble up to its lower hemisphere - is the main reason for losses of small particles in flotation. Materials and methods. Research was carried out on washing wastes of gold placers of the Petinikan-Bastakh group of deposits and on a sample of ore from the Natalka deposit. Results. It is shown that in a poly disperse system the aggregates are formed mainly from small and large particles with a density greater than the density of the disperse medium. It has been revealed that the mathematical expectation of the number of collisions of particles of the same size is negligibly small. On the other hand, provided that the concentration of small particles in a poly disperse system is not small, the relative frequency of their collision with large particles is close to 1. The obtained result proves the probability of adhesion of small particles to the surface of a large particle. It does not contradict the results obtained by other authors and methods. At flotation extraction of fine particles at the expense of their capture by fast moving coarse particles can make 50 %. Discussion. Theoretical and experimental research of the fine gold extraction technology by flotation with carrier minerals (or solid wall by another terminology), whose distinctive feature is the use of extremely related to the fine ore gold surfaces as carrier minerals - the large metallic gold extracted from the techno-genic placer. It is shown that enhancement of technological performance is achieved through the effective interaction of poly disperse particles with the formation of aggregates extracted by the mechanism of inertial flotation of large particles. Conclusion. The calculation shows that the economic effect is achieved, firstly, by increasing the production of marketable products by reducing metal losses with wastes of processing. Secondly, due to obtaining a higher total cost as
a result of reducing the unit cost of gold production in the joint processing of gold-containing raw materials. Resume. The results of the study can be used in the joint ore and placer processing according to the scheme - separation of gold enriched product from the placer with minimal metal losses with the wastes of processing - formation of goldbearing aggregates by adhesion of fine gold ore on thin plates and flakes of placer gold - flotation of fine gold ore on the carrier minerals.

Number of views: 91
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ISSN 1998-4502 (Print)                                                            ISSN 2499-975Х (Online)