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Mining Science and Technology (Russia)

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Vol 6, No 1 (2021)
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EXPERIENCE OF MINING PROJECT IMPLEMENTATION

5-15 1844
Abstract

The paper is devoted to the urgent problem of sustainable and economically secure development of enterprises in the Tver Region peat-extracting sector of the economy. Despite the fact that peat deposits are widespread in many regions of Russia, the efficiency of their industrial and economic use is extremely low. The purpose of the study was to determine the features of the assessment and analysis of the economic security of an enterprise that develops peat deposits. The paper examines the relationship between the concepts of “peat rent” and “economic security”, and also provides the author’s interpretation of their content and essence. An analysis of the existing approaches to assessing the economic security of peat extracting enterprises was carried out, and the use of the rent approach was substantiated based on the data on the peat industry enterprises used in this study. The indicators for assessing the economic security of a peat production were identified. The authors proposed a methodological approach, a feature of which was comprehensive accounting of technical, economic, and natural factors that objectively affected the level of economic security of peat extracting enterprises. The proposed methodological approach also makes it possible to develop recommendations for increasing the flexibility and adaptability of peat extracting enterprises, taking into account the individual conditions of their work. The methodological research toolkit included the fundamentals of economic theory, information methods for processing statistical data, and economic and mathematical modeling. The methodology approbation was carried out through the example of enterprises of the Tver Region peat-extracting industry, which had been at a low ebb (in protracted economic crisis) for a long time. The conclusions, recommendations, and proposals of the study were used in the development of the Regional program “Natural Resources Management and Environmental Protection” for 2017–2022 (Order of the Tver Region Government No. 414-pp of December 26, 2016 as amended on February 7, 2020).

SAFETY IN MINING AND PROCESSING INDUSTRY AND ENVIRONMENTAL PROTECTION

16-22 942
Abstract

Environmental protection is a complex ecological and economic problem, including the need to develop and implement a number of environmental protection measures to mitigate the negative impact of mining waste on all natural environment components and human health. In this regard, the study purpose was to assess the impact of Pb, Cd, Cr, and As compounds on the environment and health of the population of the Solnechny miner’s village. Based on the purpose, the following tasks were set: 1) review and systematization of literature data on the problem of technogenic dust pollution; 2) assessment of the mining industrial system as a source of ecosystem pollution with toxic elements within the closed mining enterprises impact areas; 3) development of proposals for mitigating the impact of mining activities on ecosystems and human health. The paper presents the findings of the study of the elemental status of children and adolescents living within the closed town-forming enterprise JSC Solnechny GOK impact area. The relationship between the level of technogenic pollution of the natural environment and the changes in the elemental status of the children was shown. A feature of the elemental status of the children in the study group was high content of heavy metals, including Pb, Cr, and As. Our research confirmed the data that a growing child’s body actively adsorbs compounds of toxic chemical elements. Deficiency and imbalance of microelements in the body can cause ecologically-related diseases in the child population. Individual and population carcinogenic risks (CR) caused by the As, Pb, and Cr pollution were calculated. In accordance with the acceptance criteria for the risk caused by exposure to the pollutants, the individual carcinogenic risk CR (Cr) = 1,05 · 10–3 belongs to the fourth range and is unacceptable neither for the population, nor for occupational groups. This is De manifestis risk, and when it is reached, it is necessary to carry out emergency curative measures to mitigate it. The individual risks CR (As) = 7,05 · 10–4 also exceed the acceptable level for the population. This level of pollution is subject to permanent monitoring, requires development and implementation of planned curative measures to improve the indicators of the human environment, one of which is the organization of the environmental monitoring system in the study area.

MINING ROCK PROPERTIES. ROCK MECHANICS AND GEOPHYSICS

23-30 603
Abstract

This research belongs to the field of rock physics. In recent years, in solid state physics and materials science, new knowledge has emerged about microplastic strain of various materials, including rocks. These data were obtained using high-precision micro- and nanoscale strain measurements. The very fact of the existence of the poorly studied rock property in the earth sciences requires the study of the possible influence of the rock microplasticity on the propagation of seismic and acoustic waves. The studies were carried out using three alternative methods and under different observation conditions. The field measurements were carried out in the zone of low velocities in crosshole space with transmitted waves of frequency of 240–850 Hz. The laboratory measurements were carried out on sandstone samples with transmitted (6.8 kHz) and reflected (1 MHz) waves at the strain of 10−8–10−6. The manifestations of microplasticity were recorded using high-resolution recording of signals with discretization time tdiscret = 1 μs – 40 μs and 32.5 ns. The wave amplitude variation was provided in a closed cycle: discrete increasing the amplitude from minimum to maximum and return to the initial value (A1+ → A2+ → … Amax … → А2– → A1–). In this amplitude range, an amplitude hysteresis was observed, a sign of which was the inequality of wave velocities on the upward and downward amplitude courses. This effect was recorded for all three measurement methods at different frequencies. However, the amplitude hysteresis of the wave velocity was not observed only in the measurements at full water saturation of loam. The largest amplitude-dependent change in the wave velocity reached 2% (at the accuracy of 0.02%), and the change in the attenuation value amounted to 5%. The reason for this effect could be microplastic inelasticity, which manifested itself by amplitude plateaus located within the waveform. The amplitude microhysteresis forms overall picture of the amplitude dependence of the wave velocity in wide amplitude range. Proposals for the potential use of the obtained data for solving some applied problems have been presented.

31-41 1035
Abstract

Mine surveying in mining operations is of particular importance, since all technological processes of the full life cycle of a mining enterprise and, ultimately, its competitiveness depend on the surveying quality, efficiency and reliability. Organizations independently determine the structure of mine surveying services, taking into account the methods applied and the scale of mining. To ensure safe open-pit mining of minerals, it is necessary to permanently assess and monitor the pit bench and wall rock mass condition. Misjudgement of rock physical and mechanical properties, non-observance of the minerals mining and transportation process cycle, changes in climatic conditions and other problems lead to loss of stability of rocks in all parts of an open pit, including in the areas of ore production and mining and transport equipment operation. The existing practice shows that the effectiveness of an open pit wall and bench stability calculation can be achieved using a technique that should take into account the slope deformation and failure mechanism, as well as the nature of the stress-strain state of the open pit rock mass. The studies presented in the paper are based on comparative analysis of the sliding wedge parameters for benches, dumps and roads at open pits using analytical and graphical software packages, and taking into account the static load produced by dump trucks. The study findings allow to establish that: determination of the bench slope stability and the sliding wedge width, performed by the analytical method, gives higher accuracy results than those obtained by the graphical method; the bench slope stability and the sliding wedge width depend not only on the rock physical and mechanical condition, but also on the bench height, the dump truck (plus its freight load) weight per 1 linear meter of the placement area, the distance from the slope edge and other factors; the rock mass is stable and not subject to landslide phenomena for as long as the sum of the holding forces is greater than or equal to the sum of the shearing forces; when using large-sized transport equipment of nonstandard weight in open-pit mining, it is necessary to calculate the safe width of the sliding wedges, taking into account the loads on them (per 1 linear meter), the values of which can be 1.5–2.0 times higher than those calculated for the circular-cylindrical sliding surface.

MINERAL RESOURCES EXPLOITATION

42-51 1397
Abstract

With increasing depth of exploration and process boreholes (at small drilling diameters), the probability of deviation of the borehole path from design trajectory increases many times; i. e. zenith curvature and azimuth deviation of the borehole path occur. Therefore, developing methods for keeping vertical path of the borehole when drilling deeper horizons of ore bodies is a very topical issue. The paper presents the results of developing a new bottom-hole assembly for drilling boreholes in soft rocks using screw casing centralizers, which provide good stabilizing and centering effects to mitigate horizontal departure of the hole axis from the design direction and minimize vertical curvature of the hole path (zenith angle) while maintaining sufficient drill string flexibility. The developed technical solutions provide simplicity of design and ability to adapt to wide range of mining, geological and technological drilling conditions. The feasibility of manufacturing the centralizers by own efforts and the technological feasibility of quick and easy connecting the centralizer with other elements of the bottom-hole assembly have been substantiated. The manufacture efficiency is proved by the use of inexpensive and wear-resistant materials in the centralizer armouring, for which tungsten-cobalt or titanium-cobalt hard-alloy inserts were used. In addition, prevailing volume of borehole drilling in soft rocks allowed using replaceable centering elements, as well as their repair and restoration to increase their service life. The manufactured centralizer has a low production cost due to the design simplicity and the use of inexpensive wearresistant material and will compete in the market of drilling tools and technical devices for drill string stabilization. The economic effect from the introduction of the self-produced centralizers amounted to more than 170,000 tenge per a borehole.

CONSTRUCTION OF MINING ENTERPRISES AND UNDERGROUND SPACE DEVELOPMENT

52-60 970
Abstract

Risk management is an important part of a modern enterprise activity. Currently, risk management should be included in the overall quality management system of a construction organization. Geotechnical construction, for instance, construction of metro, should also be carried out taking into account possible risks. Metro construction is connected with a number of uncertainties related to enclosing rock mass conditions, and specific geotechnical risks, which can lead to materialization of hazards with various consequences. Predicting possible hazards at all stages of a metro structure life cycle requires the ability to manage risks. The effectiveness of risk management requires detailed risk identification, which precedes the stage of determining the probability of risk (the risk assessment stage). To identify an object, it is required to determine its composition, properties, physical origin. The method of such risk cognition with division into groups through determining the essential features (grounds) is classification. To date, different classifications of risks in construction activity have been developed. The paper discusses various approaches to the classification of risks in underground construction, analyzes the feasibility of adapting these classifications to the analysis of geotechnical risks in the construction of metro facilities. The principles of classification of geotechnical risks were proposed. The typology of metro structures has been substantiated as the basis for the classification of geotechnical risks in the construction of metro facilities. The results of the development of a general form for classification of geotechnical risks during a metro construction have been presented.



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