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Date submitted2023-10-28
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Date accepted2024-11-07
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Date published2025-02-25
Radiation characteristics of coals at different stages of metamorphism
The formation of deposits and subsequent metamorphic processes that affect concentrations of radioactive elements in coal can indicate ongoing geological activities, therefore, analyzing trends in the radiation characteristics of coal throughout the metamorphic series is highly relevant. The aim of this work is to experimentally evaluate the radiation characteristics of different coal ranks (metamorphic stages) using thermoluminescent (TL) dosimetry and beta activity measurements, and to identify correlations between these radiation characteristics and data obtained from technical, elemental, and thermogravimetric analyses, as well as mass spectrometric and electron paramagnetic resonance spectroscopy (EPR) measurements. For dosimetric measurements that indirectly characterize the content of radionuclides in coal, a modified dosimetric complex and original soil-equivalent thermoluminescent detectors based on SiO2 were used. The analysis of the obtained results supports the use of TL studies to determine the ash content of coals at low and medium stages of metamorphism (coal rank B→G), while indicating that this method is not feasible for coals at higher stages of metamorphism. The correlation dependencies in the metamorphism series suggest abrupt change in the conditions of coal formation during the time range corresponding to transformation from high to low volatile bituminous coals (coal rank G→Zh→K). These abrupt changes in regional metamorphism conditions (time, temperature, pressure, oxidation-reduction conditions) are confined to the boundary of the Permian and Triassic periods (~250 million years ago), during which both the transformation of existing coal deposits and the formation of new deposits occurred.
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Date submitted2024-04-25
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Date accepted2024-06-13
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Date published2024-07-11
Evaluation of the effectiveness of neutralization and purification of acidic waters from metals with ash when using alternative fuels from municipal waste
- Authors:
- Polina A. Kharko
- Aleksandr S. Danilov
The problem of pollution of natural water objects with heavy metals is extremely relevant for the areas where industrial enterprises are located. Unauthorized discharge of contaminated wastewater, inefficient operation of sewage treatment plants, as well as leakage of drainage waters from man-made massifs lead to changes in the hydrological system affecting living objects. The article studies the composition of ash from the combustion of alternative fuels from municipal waste, and also considers the possibility of using it to neutralize sulfuric acid drainage waters and extract metal ions (Cu, Cd, Fe, Mn, Zn) from them. It has been established that the efficiency of water purification from metals depends on the pH value achieved during the purification process. The pH value is regulated by the dose of the introduced ash, the contact time and depends on the initial concentration of metal ions and sulfates in the solution. Studies on the neutralization and purification of a model solution of sulfuric acid drainage waters of a tailings farm of known composition have shown that in order to achieve a pH of 8-9, optimal for precipitation of metal hydroxides Cu, Cd, Fe, Mn, Zn and Al washed out of ash, and water purification with an efficiency of 96.60 to 99.99 %, it is necessary to add 15 g/l of ash and stir the suspension continuously for 35 minutes. It was revealed that exposure to ash with sulfuric acid waters leads to the transition of water-soluble forms of metals into insoluble ones and their “cementation” with calcium sulfate. The amount of Zn and Fe ions washed out of the ash decreases by 82 and 77 %, Al, Cd, Cu, Mn – by 25 %. This reduces the toxicity of ash, which is proved by a decrease in the toxic multiplicity of dilution of the water extract by 14 times.
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Date submitted2021-05-08
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Date accepted2022-07-21
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Date published2023-12-25
Technologies of intensive development of potash seams by longwall faces at great depths: current problems, areas of improvement
- Authors:
- Vladimir P. Zubov
- Denis G. Sokol
The results of the analysis of practical experience in the development of potash seams using longwall mining systems at the mines of OAO “Belaruskali” are presented. Positive changes in the technical and economic indicators of mines and an increase in the safety of mining operations were noted with the introduction of resource-saving technologies without leaving the pillars between the excavation columns or with leaving the pillars between the columns with dimensions at which they are destroyed by mining pressure in the goaf. It is noted that the use of mechanized stoping complexes characterized by high energy capacity, combined with large depths of development, is the main reason for the temperature increase in longwalls to values exceeding the maximum permissible air temperature regulated by sanitary standards. Based on production studies, it was concluded that the temperature regime along the length of the longwall face is determined by the temperature of rocks in the developed longwall space, heat emissions from the equipment of the power train, and the temperature of the rock mass ahead of the longwall. The conclusion has been drawn about the feasibility of using developed technological schemes in deep mining conditions, which provide a reduction in longwall temperature by 6-9 °C or more through isolated ventilation of longwall and power trains, as well as heat exchange between the airflow entering the longwall and the rocks in the developed space.
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Date submitted2022-05-17
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Date accepted2023-04-03
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Date published2024-02-29
Improvement of concentrate quality in flotation of low-rank coal
- Authors:
- Sergei A. Kondratev
- Tatyana A. Khamzina
Percentage of high-rank coal with low content of ash, moisture, and sulfur in total coal production output is low. Most of the produced coal has a low quality (lignite, bituminous coal: long-flame and fiery). Under increasing requirements for ecological cleanness of coal, the efficient use of coal products is only possible after improvement of their processing properties. The authors discuss the enhancement of flotation efficiency of low-rank coal using the mechanism of physisorption of a collecting agent in particle – bubble attachment. It is explained why the yield of concentrate with low ash content increases as a result of combination of collectors having different physical properties. It is shown that the surface activity of a heteropolar agent relative to the gas – liquid interface and the adsorption density of the agent govern its collecting properties. Based on the recovery – surface activity relationship, the correlation is found between the collecting activity of a chemical compound and the structure of its molecules. The combination of the collectors with different surface activity enables adjusting collectability and selectivity of the blend. The physisorption mechanism of collectors can be a framework for developing recommendations on modification of concentrate yield and ash content, and on selection of optimized ratios of surface activities of miscible collectors relative to the gas – liquid interface.
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Date submitted2022-10-31
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Date accepted2023-03-02
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Date published2023-12-25
Lightweight ash-based concrete production as a promising way of technogenic product utilization (on the example of sewage treatment waste)
- Authors:
- Tatyana E. Litvinova
- Denis V. Suchkov
The study is devoted to the development of a method for the technogenic raw materials utilization. Special attention is paid to the prospect of involving products based on them in the production of new building materials. The results of Russian and foreign studies on the reuse of wastes, such as phosphogypsum, metallurgical slag, waste from municipal and industrial wastewater treatment, etc., in the building materials industry are considered. It has been established that the use of incinerated sewage sludge ash in construction is a promising direction in terms of environmental and economic efficiency. The research confirmed the compliance of the lightweight ash-based concrete components to the regulatory documentation requirements for a number of indicators. As a result of the research, the composition of the raw mixture for the lightweight concrete production with incinerated sewage sludge ash as a replacement for a part of the cement has been developed. In terms of parameters, the developed concrete corresponds to standard lightweight concrete, marked in accordance with the regulatory documents of the Russian Federation as D1300 (density not less than 1.3 g/cm3), Btb2 (flexural strength not less than 2 MPa), M200/B15 (compressive strength not less than 15 MPa). Lightweight ash-based concrete is suitable for use in construction, repair of roads and improvement of urban areas.
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Date submitted2022-04-15
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Date accepted2022-11-17
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Date published2023-04-25
Uranium in man-made carbonates on the territory of Ufa
The paper presents the results of analyzing uranium content in man-made carbonates (scale crusts) on the territory of Ufa based on examination of 42 samples. The median uranium content in the investigated samples stands at 1.44 mg/kg, which is significantly lower than the background values (scales from the Lake Baikal water, a clarke of sedimentary carbonate rocks) and data on other settlements of the Republic of Bashkortostan. Low values of uranium content are probably associated with the effects of the three leading factors, i.e. specific subsurface geology of the territory (gypsum, limestone); types of water supply; water treatment processes for the centralized type of water supply. Spatial distribution of uranium in man-made carbonates is characterized with uniformity, which is disturbed in two cases, i.e. a change of the water supply type (from centralized to individual); and material of the vessels used for boiling the water. No significant differences were detected when comparing samples of man-made carbonates associated with different sources of water supply (the bucket and infiltration types of water intake) and the types of household filters.
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Date submitted2022-05-13
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Date accepted2022-09-24
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Date published2022-11-03
Rapid detection of coal ash based on machine learning and X-ray fluorescence
Real-time testing of coal ash plays a vital role in the chemical, power generation, metallurgical, and coal separation sectors. The rapid online testing of coal ash using radiation measurement as the mainstream technology has problems such as strict coal sample requirements, poor radiation safety, low accuracy, and complicated equipment replacement. In this study, an intelligent detection technique based on feed-forward neural networks and improved particle swarm optimization (IPSO-FNN) is proposed to predict coal quality ash content in a fast, accurate, safe，and convenient manner. The data set was obtained by testing the elemental content of 198 coal samples with X-ray fluorescence (XRF). The types of input elements for machine learning (Si, Al, Fe, K, Ca, Mg, Ti, Zn, Na, P) were determined by combining the X-ray photoelectron spectroscopy (XPS) data with the change in the physical phase of each element in the coal samples during combustion. The mean squared error and coefficient of determination were chosen as the performance measures for the model. The results show that the IPSO algorithm is useful in adjusting the optimal number of nodes in the hidden layer. The IPSO-FNN model has strong prediction ability and good accuracy in coal ash prediction. The effect of the input element content of the IPSO-FNN model on the ash content was investigated, and it was found that the potassium content was the most significant factor affecting the ash content. This study is essential for real-time online, accurate, and fast prediction of coal ash.
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Date submitted2021-04-19
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Date accepted2022-05-25
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Date published2022-07-13
Development of the technology of stowing the developed space during mining
- Authors:
- Evgenii R. Kovalskii
- Kirill V. Gromtsev
An analysis of the world experience in the development of potash deposits shows that the main problems arising during their development are a high level of mineral losses, an increased risk of flooding of mine workings as a result of water-proof layer discontinuance and the development of emergency water inflows in the mined-out spaces. Reduction of potash ore losses can be achieved by using a long-pillar mining system, but this method is limited by the peculiarities of the geological structure of the potash deposits and the need to preserve the continuity of the water-proof layer during its underworking. The safety of underworking of the water-proof layer can be improved by using the stowing of the developed longwall space. However, the question of the influence of the stowing on the height of the zone of water supply cracks development remains little-studied. The world experience of stowing the developed spaces in the development of layers with long pillars is analyzed and the technology of placing the stowing masses, which can solve these problems, is proposed. The considered technology and the proposed solutions are supported by laboratory tests of stowing materials and mathematical modeling of deformation zones in the overlying rocks.
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Date submitted2021-09-02
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Date accepted2022-01-24
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Date published2022-04-29
Complex processing of high-carbon ash and slag waste
The paper considers a current issue of ash and slag processing for the Polyus Aldan JSC, that has accumulated over 1 million tons of this waste. Following the results of the review of Russian and foreign literature, four promising areas of their use were selected: road construction, building materials, reclamation of disturbed lands, and inert aggregates. To assess the possibility of implementing the selected disposal directions, the samples of ash and slag waste of the enterprise were sampled and analyzed. Fuel characteristics, chemical and mineral composition, as well as physico-chemical and mechanical properties of waste were determined. Taking into account the results of complex laboratory studies and the requirements of regulatory documents, each of the selected areas of using ash and slag waste was evaluated. It was found that their disposal by traditional methods has limitations, mainly related to the high content of unburned fuel residues. The high content of combustible substances and the high specific heat of combustion with a relatively low ash content suggested the possibility of thermal disposal of the studied waste. Based on the literature data, the characteristics of the preparation of organic coal-water suspensions based on the studied ash and slag waste were selected. As a result of a series of experiments on their flaring, the expediency of using the obtained fuel at the enterprise under consideration has been proved. The authors note the possibility of using ash obtained after thermal waste disposal in the road construction industry. The prospects for further research of technologies for the preparation and combustion modes of suspension fuel based on ash and slag waste are determined.
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Date submitted2020-05-08
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Date accepted2020-06-12
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Date published2020-12-29
Gas-dynamic roof fall during the potash deposits development
In the development of practically all potash salt deposits, the study of gas-dynamic phenomena (GDP) is one of the most difficult tasks to ensure mining safety. Sudden salt and gas outbursts, dynamic breakdown, which are accompanied by intense gas release and possible broken rock carry-over into the mine workings, are associated with GDP. Geological preconditions for the GDP development are often the layered structure of the salt rock mass, the presence of interlayers and layers of salt clays. For the conditions of the Usolsky potash plant mine, complex studies of factors that characterize the possibility of gas-dynamic roof fall of the stoping rooms were carried out. In mine studies, free gases pressure and the initial velocity of gas release in the rocks of the roof workings were determined. The obtained experimental estimations were used as a parametric basis for mathematical modeling of geomechanical processes under conditions of a near-contact accumulation of free gas. The deformation of a layered salt mass produced by a room development system was described by the model of an ideal elastic-plastic medium with internal friction. The parabolic envelope of Mohr circles was used as a plasticity criterion in the compression area. In the numerical implementation, the deformation of clay contacts was modeled by Goodman contact elements. Based on the results of multivariate numerical calculations, it is established that the main factors determining the possibility of implementing GDP are the additional gas pressure at the contact, the width of the workingspan, and the distance from the roof to the first gas-containing contact. With multi-level lamination of roof rocks, there is a danger of large sources of GDP formation and the mechanism of successive fall of layers in an instant mode is implemented.
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Date submitted2019-07-22
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Date accepted2020-01-04
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Date published2020-04-24
“Ural-20R” combines loading drives evaluation in two-stage development of the face
The technological features of the use of high-performance Ural-20R combines in the conditions of potash mines in Russia are described. It is shown that when the capacity of the worked potash seams is over 4 m, a two-layer ore extraction is used. The formation of cutting process, implemented by the second course of the combine in the treatment chamber, is carried out by an incomplete section of the executive bodies. The standard control system, display and protection of the Ural-20R combine does not allow monitoring and reliable estimation of the magnitude of dynamic components on the drives of the mining machine loads, as well as tracking the feed rate of the combine to the face. The regulation of the operating parameters and the assessment of the degree of loading of the drives of the excavating machine in real time are assigned to the operator. The fundamentals of the experimental research methodology for assessing the loading of drives of Ural-20R combines with the destruction of the potash mass by an incomplete section of the executive bodies are described. The device and the operating procedure of the “Vatur” software-recording complex, which measures, records and records the electrical parameters of the drive motors of a mining machine, is described. The process studies results of forming loads on drive elements of Ural-20R combines when mining a face with an incomplete section of executive bodies are presented. It is proved that the work of combine harvesters on the undercut of the formation with a high feed rate is accompanied by significant dynamic loads on the drives of planetary organs and an overload of the drives of the Berm organs, which leads to an accelerated consumption of the resource and emergency failures of the gearboxes and motors of the extraction machine.
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Date submitted2019-05-14
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Date accepted2019-07-05
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Date published2020-04-24
Development of spacer fluids and cement slurries compositions for lining of wells at high temperatures
Article is devoted to creation of new compositions of process solutions for lining of directional wells at high temperatures. Developed compositions provide high durability characteristics of cement stone. It is shown that with an increase in packing density of cementing slurry components durability characteristics increase and porosity and permeability of cement stone decrease, whereas an increase in temperature and pressure leads to a significant increase in compressive and bending durability, which is associated with presence of quartz in them. It has been established that introduction of special structure-forming additives to the composition of developed cementing solutions allows formation of sedimentation-resistant cement systems that can provide an increase in durability characteristics of cement stone and, in general, quality lining of directional wells. Study of rheological properties of developed cementing compositions showed that the systems have high yield strength at increased temperatures and pressures. Developed compositions of water-based spacer fluids increase the cleansing degree for both casing and rocks surfaces from mud and clay cake residues, which improves the cementing quality of oil and gas wells. Mechanism for increasing the washing ability of spacer fluids and durability characteristics of cement stone, depending on composition and properties of their constituent components, is disclosed.
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Date submitted2018-12-25
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Date accepted2019-03-08
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Date published2019-06-25
Determination of the operating time and residual life of self-propelled mine cars of potassium mines on the basis of integrated monitoring data
Statistical data on the reliability of self-propelled mine cars (SPMC), operating in the potassium mines of the Verkhnekamskoye potassium and magnesium salts deposit are analyzed. Identified the main nodes that limit the resource SPMC. It has been proven that the most common failures of self-propelled cars are the failure of wheel hubs, bevel gears and traveling electric motors. The analysis of the system of maintenance and repair of mine self-propelled cars. It is indicated that the planning and preventive system of SPMC repairs is characterized by low efficiency and high material costs: car maintenance is often carried out upon the occurrence of a failure, which leads to prolonged downtime not only of a specific haul truck, but of the entire mining complex. A method for assessing the technical condition of the electromechanical part of a mine self-propelled car by the nature of power consumption is proposed. This method allows you to control the loading of the drives of the mine self-propelled car, as well as to assess the technical condition of the drives of the delivery machines in real time. Upon expiration of the standard service life of a mine propelled car specified in the operational documentation, its further operation is prohibited and the car is subject to industrial safety expertise. As part of the examination, it is necessary to determine the operating time and calculate the service life of a mine self-propelled car outside the regulatory period. A method has been developed for determining the residual service life of mine car on the basis of instrumentation control data in the conditions of potash mines.
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Date submitted2017-08-30
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Date accepted2017-11-21
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Date published2018-02-22
Simulation of operation of pneumatic compensator with quasi-zero stiffness in the electric centrifugal submersible pump unit
- Authors:
- A. N. Zotov
- K. R. Urazakov
- E. B. Dumler
The ECSPU pneumatic compensators with quasi-zero stiffness are proposed. The pneumatic compensator with quasi-zero stiffness is suggested to be made in the form of pneumatic spring assemblies having a power characteristic with a positive stiffness working area and a set of successively connected Belleville springs and a power characteristic with a working area of negative stiffness. Structurally, a set of Belleville springs is located inside the air spring and supports pneumatic compensator piston. As a result of adding the negative stiffness of the disc spring washers set and the positive stiffness of the pneumatic spring, the resulting system (the proposed pneumatic compensator) acquires a quasi-zero or specified low stiffness. The efficiency of the suggested pneumatic compensator was determined by the possibility of moving its piston from the effects of various pressure drops. It was assumed that the greater the distance the piston can move under a given action, the more effective the pneumatic compensator is. The effect of various forces acting on the piston in the case of pressure drops on the discharge line of the electric centrifugal submersible pump units (ECSPU) is simulated: a rapidly decreasing load; a sudden increase in the force acting on the piston and vibration impact. In all the considered examples, the displacement of the piston was several meters, which corresponds to the length of the working area of the power characteristic of the considered pneumatic compensator with quasi-zero stiffness. It is shown that existing pneumatic compensators, which are like gas caps, are in principle unable to provide the same displacement of the piston under the same effects on it. For their effective operation, the size of the gas cap should be several tens of meters, which is impossible in the conditions of the well. In the calculations, it is shown that it is possible to manufacture the necessary disk spring washers from various materials: steel; fiberglass FGM; beryllium bronze. Of particular interest are disk spring washers made of beryllium bronze, which are capable of withstanding up to 20 billion load cycles.
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Date submitted2015-10-14
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Date accepted2015-12-18
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Date published2016-08-22
Complex utilization of treatment wastes from thermal power plants
- Authors:
- A. N. Shabarov
- N. V. Nikolaeva
The paper investigates present-day challenges related to accumulation, processing and disposal of the coal combustion wastes. The analysis of technogenic materials beneficiation practices using gravitation, magnetic and flotation beneficiation methods has been carried out. Quantitative and qualitative microscopic analysis of materials has been conducted. The study target were ash and slag wastes (ASW) from thermal power plant and coal combustion ash. Most metals are contained in coals and coal ashes in fine-dispersed (1-10 μm) mineral form. Various native metals and intermetallic compounds, sulfides, carbonates, sulfates, tungstates, silicates, rare earths phosphates and niobates have been discovered. Each metal may occur in several mineral phases, for instance tungsten may be in the form of wolframite, stolzite, ferberite, scheelite and represented by impurities. Not only composition of compounds is diversified, but also morphology of grains: well-defined and skeleton crystals, aggregates and polycrystalline structures, crystal twins and fragments; druses, globules and microspherules; porous shapes, flocculous and splintery clusters, lumpy aggregations, etc. Based on chemical silicate analysis of main ASW components the petrochemical properties of material have been assessed. Preliminary analyses have shown that concentration of ferrum-bearing components in ASW is around 5-11 %. The magnetic method of technogenic waste beneficiation with the help of high-gradient magnetic separation has been studied. The obtained evidences show that fine ASW are most efficiently separated in separators with high-gradient magnetic system. The studies provided justification of a process flow for complex treatment of technogenic carbon-containing material, including flotation, gravitation separation, magnetic heteroflocculation enrichment and high-gradient magnetic separation. The determined complex utilization ratio has proven the efficiency of complex processing.
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Date submitted2015-10-25
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Date accepted2015-12-04
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Date published2016-08-22
Regularities of selenium and chromium behavior in redox processes during hydrometallurgic treatment of solid phase products of rhenium extraction
- Authors:
- G. V. Petrov
- M. I. Kalashnikova
- S. B. Fokina
The main source of selenium is copper anode slime. But during the pyrometallurgical treatment of sulphide polymetallic ores significant amount of selenium along with radiogenic osmium and rhenium is concentrated in the solid-phase products of acid wash extraction and cannot be extracted, as gets lost with discharged chromium-containing solutions of osmium stage. The paper presents results of research into selenium reduction in the chromium-containing sulfuric acid medium by sulfurous gas and sodium sulphite. The use of the above reducers in optimum conditions leads to almost complete recovery of selenium (VI) while selenium (IV) extraction rate is not exceeding 60 %. The chrome (III) present in solutions has no impact on the selenium extraction rate. Chrome (VI) is almost completely reduced to a trivalent state, thus its negative impact on subsequent rhenium sorption from solutions purified from selenium is excluded. In view of a high rate of selenium extraction from chromium-containing sulfuric acid solutions formed in the process of radiogenic osmium production using sulfurous gas and sodium sulphite, choice of a method for selenium reduction is to a great extent dependent on the company’s profile.
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Date submitted2015-10-21
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Date accepted2015-12-16
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Date published2016-08-22
Flow instability in producing well at flash-steam fields
- Authors:
- A. N. Shulyupin
Theoretical foundations are presented for forecasting operation instability of producing wells at flash-steam fields. The considered topic gains actuality because of the new conditions for developing geothermal power industry which call for solicitous use of the wells fund. Instability mechanism is considered: increased discharge results in the growth of the force generating the flow, which in turn results in still higher discharge. The force grows due to weakening of gravitational component which counteracts the flow in the result of depletion in the density of flash-steam mixture. It is demonstrated that due to the specifics of development of such instability in a geothermal well the reaction of well foot pressure to change in the discharge cannot influence the stability in any effective way, while the reaction of wellhead pressure may work as a stabilizing factor. Principal weaknesses are pointed out of former ideas on flow instability in flash-steam wells. The condition of stable flow should be the positive value of the derivative on discharge of the internal well foot pressure defined as the sum of wellhead and internal pressure drop.
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Date submitted2015-10-07
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Date accepted2015-12-27
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Date published2016-08-22
Phase transformations in synthesis technologies and sorption properties of zeolites from coal fly ash
- Authors:
- O. B. Kotova
- I. L. Shabalin
- E. L. Kotova
Coal fly ash is generated in the course of combustion of coal at thermal power plants. Environmental problems increase sharply without disposing that industrial waste. Technologies were tested of hydrothermal synthesis of zeolites from fly ash forming during combustion of coal at thermal power plants of the Pechora coal basin and dependences were identified of the experiment conditions on physical and chemical properties of the end product. It is demonstrated that synthesizing zeolites from fly ash is the first stage of forming ceramic materials (ceramic membranes), which defines the fundamental character (importance) of that area of studies. It was for the first time that sorption and structural characteristics and cation-exchange properties of fly ash from the Pechora basin coals were studied with respect to, Ba 2+ and Sr 2+ .
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Date submitted2015-10-06
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Date accepted2015-12-18
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Date published2016-08-22
New technology of dry benefication of fly ash from coal power plants using applied mineralogy techniques
- Authors:
- V. A. Arsentev
- E. L. Kotova
The existence of environmental and strategic need to process dumps and slagheaps of coal mining enterprises of Russia and foreign countries results in reviewing the potential of using fly ash as a technogenic mineral resource. Comprehensive studies of substance composition of fly ash from coal power plants make it possible to define rational further ways of utilizing that mineral resource substantiating the scheme of its technological secondary processing. In view of the numerous environmental problems stemming from the techniques of wet benefication and processing of that mineral resource, a technology is suggested of dry cleaning of fly ash from thermal coal power plants. Studies were carried out using a number of samples of fly ash from various power plants. The suggested criteria are used to discriminate the compounds of fly ash and quantitative and qualitative composition of particulate matter is assessed. Studies of substance composition of fly ash samples has demonstrated that the concentration of non-combusted carbon in them varies from 5 to 20 %. The principal technological procedure of cleansing in our studies was a combination of magnetic and electric separation of ash in the state of vibrational pseudo-liquefaction. It enables one to increase the throughput capacity and selectivity of the cleansing process significantly. In the result of such cleansing a stable mineral fraction is produced that contains 0.5-2.5 % of carbon, so that the purified mineral fraction can be used as a construction binding agent.
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Date submitted2015-08-19
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Date accepted2015-10-17
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Date published2016-04-22
Development of institute of financial control in construction
- Authors:
- V. P. Grakhov
- O. L. Chazova
The article is devoted to the complex research of development of Institute of financial control in construction. Based on the analysis of approaches of researchers to definition of concept «financial control», sets out its objectives and importance. Identifies and describes the characteristic features of state and non-state financial control. To examine the existing mechanisms of financial control system in construction in General, to prevent violations and to create the basis for the adoption of specific management decisions, it is proposed to study three main areas. Special attention is paid to the analysis of the current legislation in the field of formation of financial control in the construction and practice of its application. Presents substantial changes in the legal regulation of the contract system in the sphere of procurement for state and municipal needs, including the adjustment of the scheme of carrying out of competitive procedures by the customer. In this regard, an important role plays the method of calculation of the final rating of participants of procurement procedures, allowing to determine the winner in accordance with predetermined criteria and their weighting factors. This area is also complemented by the consideration of issues related to the establishment of the procedure for the implementation of banking support contracts, allowing to provide the customer more effective control over the observance of contractual obligations with suppliers (contractors, performers). The conducted researches allow to draw a conclusion about the need to rethink and address issues related to efficiency of use of budget investments in objects of capital construction. In this regard, the main priorities of improving financial control in the construction industry to achieve the desired rates of economic development.
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Date submitted2014-11-01
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Date accepted2015-01-22
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Date published2015-10-26
Project finance for strategic investment projects of mining corporations
- Authors:
- T. V. Ponomarenko
- N. A. Belitskaya
A strategic project realization in large companies leads to long-term competitive benefits, but is very costly, has high risks and complicated structural arrangement. Long payback period, high debt and risk burden result in the necessity to use project finance facilities. The research aims to find out conditions and justify the possibility of the use of project finance in Russian mining companies in terms of the new legal framework. Characteristics of projects requiring the use of project finance are determined. The article clarifies the principles and definition of project finance. Specific risks and realization problems of project finance in the Russian context are analyzed. A comparison between the Russian legal framework of project finance and regulation in foreign countries is made; examples and problems in the Russian project finance practice are shown. The results can be used by mining companies for justification of the optimal financial strategy for major investment projects realization.
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Date submitted2014-11-07
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Date accepted2015-01-07
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Date published2015-10-26
The concept of reducing the risks of potash mines flooding caused by groundwater inrush into excavations
- Authors:
- V. P. Zubov
- A. D. Smychnik
Results of the analysis of factors influencing the probability of accidental groundwater inrush into mine workings of salt (potash, potassium and magnesium) mines are given in the article. The cases of the potash mine flooding that occurred in different countries with developed mining industry are given. It is shown that at the present technical and scientific level of solving this problem the unexpected groundwater inrush in potash mines usually results in the shutdown of the enterprise and negative ecological consequences. It is pointed out that the underground waters flow into the mines through water-conducting fractures of either natural or technogenic origin which location and influence on a mine was almost impossible to predict at the design stage under existing regulations. The concept of reducing the risks of potash mine flooding caused by underground waters in-rush is formulated. Administrative and technical measures which allow reducing the risks of potash mine flooding caused by groundwater inrush into the excavations are considered.
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Date submitted2009-09-01
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Date accepted2009-11-19
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Date published2010-06-25
Structural features of gas-liquid mixture
- Authors:
- Yu. D. Muraev
- V. L. Shkryabin
- Sh. Z. Guseinov
the effectiveness of the foam flush drilling connects of foam ability to reduce the friction force and drilling shaft oscillation. The main factors are foam viscosity and foam bubble’s diameter.
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Date submitted2009-08-01
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Date accepted2009-10-29
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Date published2010-02-01
Increase of competitiveness of russian and belorussian potash companies owing to perfection of sale policy
- Authors:
- T. V. Ponomarenko
- A. N. Sultani
The potassium companies of Russia and Belorussia, developing the unique deposits of potassium salts, provide more than 40 % of the world production of potassium fertilizers. Therefore economic efficiency from their activity considerably influences to the world market of potassium. Being the companies which export more than 80 % producible products «Belaruskali», «Uralkali» and «Silvinite» have problems with the transport of fertilizers in Brazil, India, China. Therefore for the increase of competitiveness of these enterprises it is necessary to develop an effective logistic chain which would take into account their geopolitical features.
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Date submitted2009-08-26
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Date accepted2009-10-25
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Date published2010-02-01
The improvement of selective extraction of thick potash seams mined with room and pillar mining method
- Authors:
- Yu. G. Sirenko
- M. Yu. Brychkov
- E. R. Kovalsky
Technological scheme of selective extraction of a complex thick potash seam on the basis of cutting machine «Bucyrus Model 25 M0» is proposed. Stable pillars’ width and room dimensions are calculated. Economical effect is also presented.