Search

The study of quantitative and qualitative indicators of the non-metallic mineral deposits mining based on recognized methods of economic and technological assessment to determine the damages and the development of technical–technological measures for the providing the mining industry of construction and bulk materials from the crisis in the post-war period. To assess the state of non-ore mineral deposits, the authors of the article used the following research methods: critical analysis of literary sources, statistical processing of data on the mines functioning and the probability of their manifestation in specific mining and geological conditions. Based on the selected UNIDO method, which is used for the evaluation of high-budget projects, the quantitative performance indicators of the selected quarries of non-ore raw materials have been established. Systematization and visualization of the obtained results were carried out with the help of Excel calculation tables from the available software product MS Office. The main problems associated with the activity of mining enterprises that develop deposits of non-ore useful minerals are highlighted. Qualitative and quantitative values of the work of the selected mines have been prepared according to European standards, which serve as initial data for assessing the economic attractiveness and the possibility of their restructuring in the post-war period. A forecast of the development of the industry is provided on the example of individual technological units of entrepreneurial activity for the nearest period. Dependencies of changes in production capacity indicators of mining enterprises developing non-ore mineral deposits have been established. Data on the spatial distribution of reserves of construction and backfill materials (gravel, sand, clay) were studied. Using generally recognized international methods of assessing the efficiency of enterprises, changes in the priority of mine development were determined depending on the needs of the Ukrainian economy and the destruction of territories caused by military actions, that appeared due to the aggression of the RF. The effectiveness of the methodology was proposed and confirmed, which allows determining the operative parameters of mines, which are mining non-ore mineral deposits. It gives the possibility to assess the economic attractiveness of individual mines and subsequently predict the possibility of their restructuring for the introduction of the innovative equipment and technologies in accordance with generally recognized international standards. [ABSTRACT FROM AUTHOR]

The novelty of the paper is the analysis of the possibilities of reducing the operating costs of a mine water pumping station in an abandoned coal mine. To meet the energy needs of the pumping station and reduce the carbon footprint, "green" energy from a photovoltaic farm was used. Surplus green energy generated during peak production is stored in the form of green hydrogen from the water electrolysis process. Rainwater and process water are still underutilized sources for increasing water resources and reducing water stress in the European Union. The article presents the possibilities of using these waters, after purification, in the production of green hydrogen by electrolysis. The article also presents three variants that ensure the energy self-sufficiency of the proposed concepts of operation of the pumping station. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to formalize knowledge management based on the use of methods of uncertainty analysis in the organization, which will allow collecting missing or incomplete information, as well as finding appropriate management solutions. Design/methodology/approach: The methodology consists of three stages: (1) analysis and evaluation of description of uncertainty in LCA; (2) recommendation of the most appropriate measures of uncertainty; (3) construction of a new hybrid method for LCA based on the fuzzy theory. Findings: Alternative ways of modeling of uncertainty, such as Monte Carlo (MC) and fuzzy sets (FS) (possibility distributions) are discussed. Based on literature data on hybrid LCA and uncertainty in LCA an overview has been developed. It is concluded that given possibility to analyze different situations creates knowledge experience and its usage due to the knowledge management process. Research limitations/implications: given research propose the new approach on the environment investigation that forms additional knowledge for making decision support in management process. But additional investigation must be completed and should include suggestions for future research on the implementation of knowledge management in the decision support system of organization. Practical implications: the study examines the practical results of applying the proposed approach to uncertainty analysis using specific methods that reflect the impact of risk on the consequences of the commercial results of a mining company's project implementation. Social implications: Proposed research could be impactful to the society by giving methods of environmental investigation with possibility of accounting the factors of uncertainness. Originality/value: the new hybrid LCA method is proposed when uncertainty is due to both randomness and the lack of, or incomplete, information. The development of such methods is necessary for the appropriate uncertainty analysis in LCA. A set of such techniques are knowledge management tools that support the decision-making process through a clearer understanding of the situation and its implications. [ABSTRACT FROM AUTHOR]

Purpose. The research purpose is to study the conditions for mining deposits of metamorphic and igneous origin to produce crushed stone products in conditions of limited electricity supply. Methods. The research uses an integrated approach, including data analysis on quarry field spatial dimensions and the overburden rock thickness, which provides the basis for identifying deposits into basic groups. For the identified groups of deposits, taking into account the hydrological characteristics of non-metallic deposits and their parameters, patterns have been determined that characterize the change in the normative atmospheric precipitation inflow, based on the quarry field area and the change in the specific costs for water drainage depending on the studied quarry field type. Based on data on technical characteristics of mobile and semi-stationary units and aggregates, the parameters of physical-mechanical properties of granites and diorites, technical-technological solutions for the formation of complexes for processing raw materials for the production of crushed stone products are proposed. Findings. Problems arising during mining operations under conditions of limited electricity supply, which is caused by mass attacks on Ukraine's energy infrastructure, have been revealed. A systematization of deposits of igneous and metamorphic origin for mining of rock building materials, which are the basis for the production of crushed stone products, has been developed. The rates of water inflow into the mined-out space depending on the quarry field spatial parameters and the depth of mining operations have been studied. Technological schemes of the apparatuses of a complex for processing raw materials for production of crushed stone products and the apparatuses of a complex for processing siftings are proposed. Originality. Dependences of possible water inflow into the mined-out space of the quarry and change in energy consumption for water drainage have been determined, taking into account the accepted classification criteria, namely the quarry field spatial dimensions, the overburden rock thickness and the quarry depth. Practical implications. The obtained data on the possible water inflow into the mined-out space of the quarry and change in energy consumption for water drainage make it possible to assess the efficiency of pumping units. The proposed technicaltechnological solutions on formation of complexes for processing raw materials to produce crushed stone products have been developed in accordance with the fundamental provisions of the Law of Ukraine "On approval of the National program for the development of the mineral resource base of Ukraine for the period up to 2030". [ABSTRACT FROM AUTHOR]

According to the tests results of the technology of reverse jet flow, to balance the geometric and physical parameters of the active zones of the reaction channel of the underground gas generator during the gasification of low-power coal seams. The parameters of activation of the oxidizing and reducing zones of the fire blowout were established, taking into account the outgassing of the coal seam in space and time, the impact of mining and geological parameters as well as geotechnical and thermochemical processes, securing the even advance of the fire blowout along the length of the reaction channel of the underground gas generator. It was established that the intensification of the gasification process of thin and ultrafine coal seams increases the quantitative and qualitative parameters of exothermic and endothermic reactions, which have an impact on increasing the efficiency of the underground georeactor and determines the quality parameters of the gasification product. [ABSTRACT FROM AUTHOR]

Mathematical modelling of rock mass breaking using blasting has been applied to obtain formulas for the calculation of crush zone radii, intensive fragmentation, and crack formation around the charging cavity in the structure, diameter of the charging cavity, diameter of the charge itself, detonation characteristics of an explosive, boundaries of the rock strength, rock mass jointing, and mineral compression under the effect of rock pressure. The methods have been developed to calculate parameters of drilling and blasting operations (DBOs) while driving the mine workings based upon the idea of the arrangement of blastholes in terms of areas they occupy in a fore-breast as well as upon their location relative to break-off outline. Stage one of the methods involves calculating and designing burn cuts where a distance between blastholes is determined with the help of a fragmentation zone radius. Stage two means calculation of both specific and total explosion consumption per borehole bottom, line of least resistance (LLR) for a borehole in terms of intensive fragmentation, areas of borehole groups, borehole number, analytical and actual distance between boreholes, actual charge amount per borehole, and actual specific and the total explosive (E) consumption per borehole bottom. The methods have been tested in the operating ore mine while driving a mine working. Emulsion explosive (EE) Ukrayinit-PP-2 has been applied. The developed methods have been used to calculate DBOs parameters for the explosive. Trial blasts demonstrated the good firing of a borehole bottom and uniform ore fragmentation; a high coefficient of borehole use has been supported. [ABSTRACT FROM AUTHOR]

Mining systems for ore deposit extraction with the backfilling of the goaf solve the problem of preserving the surface and the complete extraction of rich ores. This paper considers the filling of mined-out stopes with a viscous fluidal solution for the formation of an artificial strong massif, which results in a conglomerate formed on contact with the ore deposit. It was established that exogenous fracturing at the Pivdenno-Belozirske deposit significantly affects the stability of the sides and ceilings in the chamber. This phenomenon can be observed at the first stage of processing. At chambers (the second stage of processing), the artificial rock mass is exposed. It has been established that the chamber mining systems do not ensure the operational stability of the vertical outcrop in the zones of exogenous intensive fracture of the rock mass, especially in the places where they intersect. The zonal location of intense fracture was established along the strike and dip of the steep ore deposit, as was its importance in the formation of rock fallouts. An analytical solution algorithm has been developed to determine the penetration of the backfilling mixture in the plane of the intersection of zones of intense cracking, with opposite azimuths of incidence at steep angles of macrocracking. The features of penetration into microcracks of the backfilling mixture used at the mine, which are affected by their granulometric and physicochemical compositions, have been determined. The influence of the height of the layer and the procedure of backfilling the chamber space in the liquid phase on the formation of the necessary pressure for the opening of a microcrack was studied. The priority of backfilling the exogenous macrocracks with significant gaps and those between tectonic blocks with mixtures has been analytically substantiated and confirmed by experimental methods of research in the mine. [ABSTRACT FROM AUTHOR]

Laboratory and industrial studies have established the total impact of environmentally hazardous substances, taking into account the distance from the source of emissions and the specific consumption of explosives. With the help of physicochemical analysis and biological testing, the dependence of the change in the conditional indicator of damage to bioindicators with an increase in the distance from the source of emission and the specific annual consumption of explosives was revealed. A methodology for calculating the environmental assessment of the state of atmospheric air around the mine ventilation shaft has been developed. The exponential dependence of the influence of surface concentrations of environmentally hazardous substances on the damage of bioindicators at the cellular and organismic levels has been established, which makes it possible to assess the state of atmospheric air at industrial sites of iron ore mines. The proposed technology of sand drilling, which involves the use of emulsion explosives in mining ore deposits in chamber development systems will reduce emissions of environmentally hazardous substances into the atmosphere and increase the level of environmental safety of iron ore mines. [ABSTRACT FROM AUTHOR]

Purpose is to study influence of a longwall face advance on the geomechanical situation in the neighbourhood of a mining site based upon determination of changes in standard and critical subsidence of the immediate roof rocks. Methods. To study a geomechanical situation in the neighbourhood of a mining site the authors have applied software product GeoDenamics Lite developed at Dnipro University of Technology. The software product relies upon a calculation procedure of stress-strain state of rocks by Professor O.V. Savostianov. Expediency of the software selection is based upon the supported control and adaptation of a coal mining technique to changes in geodynamic stress fields in the anisotropic rock-coal medium impacting temporal and spatial changes in the technological parameters. Findings. The basic problems have been singled out connected with certain changes in a longwall face advance. For the first time, an analytical scheme of tangential stresses within the immediate roof rocks has been developed for Lisova mine of SE Lvivvuhillia under the conditions of coal seam mining by means of the paired longwalls which makes it possible to determine both physical and geometrical parameters of standard loads within the formation. Originality. Dependencies of temporal and spatial changes in subsidences and horizontal displacements of rock layers of the immediate roof have been defined being 5.2 m for the upper rock pack and 3.9 m for the lower pack if the longwall longwall face advance is 1.9 up to 4.8 m/day. Both physical and geometrical parameters of the reference pressure have been defined as well as the parameters of lower sandstone pack in the process of the main roof subsidence. Impact of the extra pressure forces on the immediate roof rocks has been analyzed at the moment of critical lowerings of the immediate roof rocks. In this context, standard loading from the overlying formation in addition to tangential stresses in the roof result in rock failure due to vertical cracks above a longwall face. Practical implications. The engineering methods have been developed making it possible to identify impact parameters of a longwall face advance on the geomechanical situation in the neighbourhood of a mining site. In future, it will help forecast changes in the reference pressure around a longwall face while preventing emergency settlement of the powered support. [ABSTRACT FROM AUTHOR]

Ukrainian electricity production sector is in a critical situation. It is necessary to increase the coal production to ensure the continuity of electricity production. In this paper, an analysis of coal mining in western Donbas, Ukraine, was presented. The crucial thing is to increase coal production in this region. The new calculation schemes were proposed to increase coal extraction in Donbas mines. The coal pillar parameters, which are necessary for the effective control of the rock pressure caused by the stooping, were substantiated. The obtained parameters for the coal pillars will allow extracting more coal, safely and quickly dismantling the mechanized complex and effectively protecting the ongoing mine work. The case study helps determine the coal losses because of pillar leaving and to improve the stability of the main haulage roads located in the zone of the stooping effect as well as to achieve additional coal production in the mine. Such a technological solution allows to extract the coal more fully at the final parts of the extractive columns and to obtain an additional economic effect. The increase in coal production in coal mines of western Donbas will increase the energy security of all Ukraine. [ABSTRACT FROM AUTHOR]

Based on both theoretical and practical experiences, the measures aimed at controlling emergency shutdowns of stopes have been highlighted. These stopes are connected with the emergency rigid settlements of powered complexes. In terms of the Western Donbas mines, there are certain risks of a shutdown of stopping operations within the zone of primary roof caving. Thus, the causes of emergency rigid settlements of the support may include the following: layers of the main roof rocks are hanging and not timely delaminated; sudden changes in lithology; hydraulic overloading of the main roof; structural flaws of support under certain conditions of its use, etc. In this paper, the theoretical method of scientific cognition was applied, which, with its help, makes it possible to switch from single low-efficiency measures to a set of actions aimed at preventing any uncontrolled situation. Obtaining certain generalized knowledge means obtaining a much deeper representation of reality, penetrating into its essence. The study also involves statistical analysis, being the basis for outlining a zone of primary caving where a high degree of risk is observed. Certainly, the generalization of these measures does not solve the problem completely. Consequently, there will be further attempts to search for and achieve principal new solutions in the future. [ABSTRACT FROM AUTHOR]

Abstract Results of computer modeling of stress-deformed state of rock massif with the use of software FLAC 5.00 in zones of geological fault influence with amplitude that does not exceed 3 m are presented in the article. According to the results of the modeling, the dependences of vertical stress change in handing wall and foot wall of geological fault with variable fault plane amplitudes and contour well deformation have been obtained. Using the interpolation data method, 3-D grid visualization of vertical stress in space is got. The analysis of modeling results on full movement vectors is also presented. Results of previously conducted analytical calculations are compared with received data. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in practical application can be used to determine the location of underground gas generator wells. Also these investigations will give the opportunity to maintain the necessary exploitation wells crosscut. Besides, it will allow consume coal reserves in the faulting zones in order to obtain power and chemical generator gas, chemicals and heat. [ABSTRACT FROM AUTHOR]

The paper presents the results of analytical and experimental studies of the hydrodynamics of the translational−rotational motion of incompressible gas flow within a working space of a variable-geometry vortex heat generator. The terminal velocity and pressure have been identified analytically. The effect of vortex generation on the ratio of the parameters has been analyzed. A mathematical model has been developed with a simplified design scheme that simulates the movement inside a vortex channel with fixed elements. On the basis of mathematical modelling, the influence of the apparatus-constructive (AC) design of the working space of a vortex heat generator on the generation of vortices inside the apparatus has been analyzed. The influence of the main geometric and hydrodynamic parameters of the device on the indicators of its energy efficiency has been investigated. The obtained models show the critical regions where the most intense cavitation zones are possible. An analysis of the hydrodynamics of the incompressible gas motion within the working space of the newly designed vortex heat generator with variable geometry has helped define both the terminal velocity and pressure. In addition, the effect of the facility geometry on the generation of vortices favoring cavitation was determined. The model studies have been carried out in terms of liquid loading changes in the 0.001–0.01 m3/s range. The changes in a velocity field within a working channel have been analyzed for the channel geometry, where a cone angle γ is 0° to 25°, with 130, 70, and 40 mm widths for the working channel. It has been identified that a sufficient axial symmetry of the heat carrier along a vortex accelerator enables the heat carrier inlet through a turbulizing nozzle. The dependence of the nozzle area, the effect on the efficiency of the vortex heat generator angle of attack of the vortex accelerator, and the ratio of the length and diameter of the vortex zone of the heat generator to its energy efficiency in general have been defined experimentally. These studies could be instrumental in the design of vortex heat generators whose geometry corresponds to the current requirements concerning energy efficiency. It has been found that the geometry of the vortex accelerator improves the operation of the heat generator by 35% in comparison with similar available designs. [ABSTRACT FROM AUTHOR]

This paper represents the results of experimental studies of physical modeling of the underground coal gasification process in terms of implementation of design and technological solutions aimed at intensification of a gasification process of thin coal seams. A series of experimental studies were performed in terms of a stand unit with the provided criteria of similarity to field conditions as well as kinetics of thermochemical processes occurring within a gas generator. Hard coal (high volatile bituminous coal) was selected as the raw material to be gasified, as that coal grade prevails in Ukrainian energy balance since it is represented by rather great reserves. Five blow types were tested during the research (air, air–steam, oxygen–steam, oxygen–enriched, and carbon dioxide and oxygen). As a result, the effect of tightness of a gas generator on the quantitative and qualitative parameters of coal gasification while varying the blow by reagents and changing the pressure in a reaction channel has been identified. Special attention was paid to the design solutions involving blow supply immediately into the combustion face of a gas generator. The experimental results demonstrate maximum efficiency of the applied gas generator design involving flexible pipelines and activator in the reaction channel and a blow direction onto the reaction channel face combined with blow stream reversing which will make it possible to improve caloricity of the generator gas up to 18% (i.e., from 8.4 to 12.8 MJ/m3 depending upon a blow type). Consideration of the obtained results of physical modelling can be used with sufficient accuracy to establish modern enterprises based on the underground coal seam gasification; this will help develop more efficiently the substandard coal reserves to generate heat energy as well as power-producing and chemical raw material. The research conclusions can provide technical reference for developing a new generation of underground coal gasification technology. [ABSTRACT FROM AUTHOR]

The objective is to analyze the dynamics of the underground water of a mine field based on the study of the geofiltration process of the rock mass disturbed by mining to achieve safe extraction operations as well as subsurface territories at the stage of the mining enterprise closure. Numerical modeling, based on a finite difference method under the conditions of multifactority and definite uncertainty of processes of transformation of technogenic environment of a mine field, helps solve a problem concerning underground water dynamics forecasting. A hydrodynamic model of the M.I. Stashkov mine was developed while solving option series of epignosis problems in terms of the chronology of mine field stoping. The abovementioned made it possible to identify regularities of the history of filtration, the capacity parameters of rock mass and the expansion of areas of heightened hydraulic conductivity as well as to evaluate qualitatively the water balance components of a carbonic watered formation and an overlying one. The stage of mining closure helped obtain the forecasting hydrodynamic solutions. The efficiency of measures, concerning reduction of water ingress into mine workings and the mitigation of surface ecological effects of mine flooding was evaluated quantitatively. It was determined that implementation of the water control procedures makes it possible to perform a 10–38% decrease in water ingress. In this context, they may be applied both independently and simultaneously. In terms of mine closure and flooding, a period of complete underground water recovery takes three years; in the process, surface zones of potential waterlogging and swamping are developed within the floodplain of Samara River, located at the territory of Western Donbas (Ukraine). The scientific novelty is to define regularities of hydraulic conductivity transformation of the rock mass of a mine field starting from the mine working roof fall, up to its compaction during the mine operation period. To do that, nonstationary identification problems were solved, using numerical modeling. The abovementioned makes it possible to improve the reliability of hydrodynamic prognoses and develop technological schemes to control water at the state of the mine closure. [ABSTRACT FROM AUTHOR]

The research was carried out by means of implosion plasma generators with conical and hemispherical compression chambers to conduct a quantitative assessment of the boundary temperature of super dense plasma jets. It was proved experimentally that nuclear transformations in metals are caused by the impact of super dense plasma jets (11,..., 12) × 103 kg/m3. The boundary temperature of these jets was evaluated. It was estimated that the nominal boundary temperature of the studied implosion plasma generators is 106 К. The pressure in the target at the penetration of the super dense jet (~12,000 kg/m3) at the speed of 28,000 m / sec is more than 30 ТPa. The boundary temperature was estimated and proved to depend on the pre-determined values only slightly. It was experimentally established that stable isotopes of manganese Mn55 (up to 27%) are formed in iron targets as a result of high temperature plasma jet penetration. The appearance of manganese must be related to iron transformation into stable isotopes Fe56 and Fe54. The obtained results may be applied for investigating structural changes in metals under the conditions of impulsive super high temperatures and pressures. This method can be also used as a testing ground for studying the physical conditions of forming chemical elements as well as super dense plasma jets. [ABSTRACT FROM AUTHOR]

The effect of basic parameters of the channels of disk pulse devices on the heat exchange efficiency was studied both analytically and experimentally, especially in terms of pulse acting on the heat carrier. A methodology to determine the main parameters, namely the pressure and the temperature of the heat carrier as well as the pulse effect on the fluid, was proposed. The mathematical models of the effect of the structural and technological parameters of the channels in the disk pulse device on the heat exchange efficiency were developed. The models' adequacy was proved based on a series of experimental studies involving devices with one-stage and multistage systems of pulsed heat carrier processing. This enabled the development, testing, and implementation of practical construction designs of pulse disk heat generators for decentralized heating of commercial and domestic buildings with one-stage and multistage systems of pulsed heat carrier processing. Taking into account the results of the mathematical modeling, the developed method of multistage pulse action was proved experimentally and implemented in regard to the structural design of a working chamber of the disk pulse heat generator. An efficient geometry of the working chamber of the disk pulse heat generator was specified for its further integration into the system of decentralized heat supply. One of the developed heat generators with the multistage pulse action on the heat carrier was integrated into the heating system of a greenhouse complex with a 0.86–0.9 efficiency coefficient. [ABSTRACT FROM AUTHOR]

The paper presents an experimental study on the formation process of burden surface texture on the blast furnace throat and its influence on the radial distribution of gas flow. The study was performed with the application of blast furnaces equipped with a bell-type charging device using radio-isotope means for the control of burden surface texture (profile) and burden surface level, i.e., gamma locators for burden surface texture. The study was carried out under the conditions of an operating blast furnace in an iron and steel plant using a unique GEOTAPS system for automated control of geometric and temperature parameters of burden material surface on the blast furnace throat. The influence of the surface texture on the gas flow distribution was also investigated. The possibility of a self-stabilization effect for burden surface texture and gas flow in an operating blast furnace under suitable conditions was experimentally proven. As a result of the experimental study performed, four ways of energy-saving technology implementation were determined for the control of blast furnace melting based on the data on the burden surface texture and previously unknown regularities of surface layer formation of burden material on the throat of an operating blast furnace with a bell-type charging device. The main idea of the paper is the development of automated control for the radial distribution of burden material and gas flow using actual or predicted surface texture parameters as important intermediate factors that both describe the process and have a significant simultaneous influence on it. [ABSTRACT FROM AUTHOR]