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Date submitted2022-09-26
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Date accepted2023-03-23
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Date published2023-12-25
A new diamond find and primary diamond potential of the Chetlas uplift (Middle Timan)
In the previously poorly studied southeastern part of the Chetlas uplift in the Middle Timan, a new occurrence of diamond satellite minerals and a diamond grain were found in the modern channel sediments of the Uvuy River basin. In order to assess the prospects of the area under consideration for identification of diamondiferous objects of practical interest, a characteristic of chromium-bearing pyropes and chromospinelides as the main kimberlite of diamond satellite minerals are given and the diamond grain itself is described. The material for the research was 16 schlich samples, each with a volume of 8 to 15 l. The minerals were studied using optical and scanning electron microscopy, Raman spectroscopy, laser luminescence and X-ray diffraction (Debye – Sherrer method). It is shown that among the pyropes, most of which correspond in composition to minerals of the lherzolite paragenesis, there are varieties belonging to the dunite-harzburgite paragenesis, including those belonging to diamond phase stability regions. Among the studied chromospinelides, chrompicotites and aluminochromites similar in composition to those found in rocks such as lherzolites and harzburgites, as well as in kimberlites, were identified. A diamond grain found in one of the samples has the form of a flattened intergrowth with distinct octahedron faces, complicated by co-growth surfaces with other mineral grains that have not been preserved to date. The discovery of the diamond and the established signs the formation of aureoles of the diamond satellites minerals in the channel sediments of the studied area open up the prospects for discovering their primary sources here.
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Date submitted2022-07-15
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Date accepted2022-12-13
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Date published2023-02-27
Mathematical modelling of displacement during the potash ores mining by longwall faces
In favourable mining conditions, in particular at the Starobinskoye potash deposit (Belarus), longwall mining systems are used. They cause a high human-induced load on the subsoil, including intense deformation of the ground surface. The presented investigations are aimed at studying the dynamics of the ground surface displacement during the longwall face advance. Mathematical modelling was carried out in an elastic-plastic formulation with numerical implementation by the finite element method. The condition for the roof rocks collapse was opening of the contact between the seams when its boundaries were reached by shear fractures or formation of the tensile stresses area at the outcrop. With the working front advance, an increase in subsidence is observed, followed by its stabilization to a value determined by the process parameters of mining operations and the physical and mechanical properties of collapsed rocks. In this case, each point of the ground surface experiences sign-alternating horizontal deformations: when the front approaches, it causes tension, and when it moves away, compression. The obtained results of mathematical modelling are in good agreement with the data of instrumental measurements of the ground surface displacements, which indicates the adequate description of the rock mass deformation during the slice excavation of sylvinite seams by longwall faces.
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Date submitted2021-03-18
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Date accepted2021-11-30
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Date published2021-12-27
Deformations assessment during subway escalator tunnels construction by the method of artificial freezing of soil for the stage of ice wall formation
- Authors:
- Evgenii M. Volokhov
- Diana Z. Mukminova
The work is devoted to the study of the processes of displacement and deformation of the surface during the escalator tunnels construction of the subway by the method of artificial freezing of soils. The features of the construction and freezing technology, the rocks characteristics in which the escalator tunnels made are considered. The data of specially organized, full-scale surveying observations of deformations on the earth surface are presented. The main factors influencing deformation processes in the frozen strata of a layered inhomogeneous rock mass with inclined tunneling are determined, the complexity of the predictive task and the need to simplify the design scheme are shown. The work is focused on the assessment of the least studied geomechanical processes of soil heaving-uplifts and deformations during the periods of active and passive freezing stages. When studying the displacements processes of the earth surface and rock mass, the finite element method and analysis of the obtained data using field observations of displacements were used. A simplified calculation scheme is proposed for modeling, which allows taking into account the uneven influence of frozen rocks of an inhomogeneous layered rock mass with a large inclined tunneling. The satisfactory convergence of the data of field surveying observations on the earth surface and the results of modeling geomechanical processes for the period of active and passive freezing stages is shown. The proposed calculation scheme is recommended for the prediction of deformation at the stages of underground construction, characterized by the development of the most dangerous tensile deformations of buildings and structures on the surface.
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Date submitted2020-06-16
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Date accepted2020-07-13
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Date published2020-11-24
Study of Aluminum Influence on the Adhesion of Stainless Steel in Flame Spraying
This paper is dedicated to a study of aluminum influence on the improvement of surface adhesion strength. The main purpose of this work is to investigate the strength of adhesion to the substrate by mixing flame spray powder with aluminum, which not only possesses high corrosion resistance and conductivity, but also provides additional strength, as it combines and reacts with other components of the powder. Research results of sandblasting dependence on surface roughness parameter Ra are demonstrated. The paper describes authors’ original device for a measuring instrument “Profilometer”, which was also used for measuring roughness parameter in order to obtain comparative results. Authors present results of adhesion measurements given obtained values of surface roughness by mixing nominal chemical composition of PR-30X13 powder, used as a testing material, with aluminum, which reacts with oxides on the surface of steel substrates, imparts strength to the bonding between the coating and the substrate, protects the base metal due to a combination of chemical components of the powder and creates a layer of dense surface coating. These dependencies are analyzed and parameters, exerting the greatest influence on their values, are identified. Taking into account the results obtained through numerical modeling, authors propose a mathematical model of a dependency between adhesion strength and certain values of surface roughness for different chemical compositions of flame spray powder. These studies will help in the development of certain material types for spraying and hardening of steel parts and products in order to improve their durability.
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Date submitted2018-09-10
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Date accepted2018-11-06
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Date published2019-02-22
Comparative analysis of zincand tin oxidation with acids at room temperatures
- Authors:
- S. D. Pozhidaeva
- L. S. Ageeva
- A. M. Ivanov
The paper analyses the parameters of deep oxidation of zinc and tin by copper (II) compounds and molecular iodine in the presence of molecular oxygen and hydrogen peroxide, as second oxidizers working synchronously with them in various media (aqueous, aqueous-organic and organic) with the participation of mineral and carboxylic acids close to room temperature. The contribution of the reactivity of the metal to its rate of consumption, especially the average, is often much less than the contribution associated with the release characteristics of the working surface, determined by the rates of accumulation of surface deposits of metal oxidation products, their strength and adhesion characteristics their destruction and shifting into the bulk phase.
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Date submitted2017-09-11
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Date accepted2017-10-30
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Date published2018-02-22
Provision of adhesion strength of gas-thermal coatings on piston rings of quarry transport engines
- Authors:
- Yu. Olt
- V. V. Maksarov
- V. A. Krasnyi
The main trend in the development of modern diesel engine manufacturign is the creation of high-powered, reliable and economical internal combustion engines (ICE), which are widely used in various industries, including mining machinery. The application of the methods of gas-thermal and gas-plasma coating for obtaining wear-resistant layers on piston rings for large internal combustion engines of quarry transport – diesel locomotives and dump trucks- is considered. It is shown that the abrasive-jet machining of base coat is widely used as a preparatory operation before coating process, and the roughness of the working surface of the rings after abrasive-jet machining has a significant impact on the adhesion strength of the coating with the base material. The selection of the surface roughness and the conditions of abrasive-jet machining for increasing the coating adhesion strength to the base coat significantly determines both the thickness of the coating and the reliability of the part itself. The aim of the paper is to investigate the dependence of the adhesion strength of a gas-thermal wear-resistant coating of piston rings of large engines of quarry transport, including dump trucks and diesel locomotives, from the roughness of the working surface after abrasive-jet machining, which in turn depends on its modes (distance to the nozzle exit section, the number of passes, the working air pressure, the shot change rate). The working surface adhesion strength of piston rings with diameter of 210 mm coated with molybdenum and steel wire composition was investigated by the twisting angle at which the coating peeled. It is shown that the roughness providing a twist angle greater than 35° should be more than 22 μm, which does not cause coating peeling off. Modes of abrasive-jet machining providing the specified values of roughness: working air pressure is 0.4 MPa, distance to the nozzle exit section is 110 mm, the number of passes is 2, and the shot changes after processing 40 mandrels.
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Date submitted2016-09-16
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Date accepted2016-11-12
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Date published2017-02-22
Possibilities of seismic exploration for crystalline basement study
- Authors:
- A. N. Telegin
Possibilities of seismic methods of reflected and refracted waves have been examined for the purposes of detailed study on crystalline basement structure. Investigation of depth and structure of the basement plays an important role in the exploration of various deposits. Sedimentary cover is usually associated with oil and gas reserves. Ore deposits are formed in the basement rocks, basement splits and structure of its surface have a genetic relation not only to ore minerals, but also to oil resources. Reflection seismology is one of the main seismic methods of investigating structural geometry of the sedimentation mass, forecasting its material composition and possible hydrocarbon reserves. However, its possibilities for investigating crystalline basement are limited. Basing on many years’ experience of reflection seismology and physical modeling it has been identified that actual roughness of basement surface limits the obtainable amount of waves reflected from it. Possibilities of reflection seismology for basement structure study are mostly related to investigation of discontinuous faults as diffraction objects using diffracted waves. Method of refracted waves combined with modern procedures and material processing aimed at getting dynamic seismic sections holds much significance for the basement study, especially in the process of surface mapping and, to a lesser extent, in investigating discontinuous faults.
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Date submitted2015-10-07
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Date accepted2015-12-01
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Date published2016-08-22
Evaluating possible industrial applications of combustible shales and shale ash wastes
- Authors:
- N. K. Kondrasheva
- S. N. Saltykova
Today energy consumption is constantly growing while explored reserves of easily accessible oil are depleting, which is a reason why most countries tend to diversify their energy mix, develop non-hydrocarbon energy sources and use domestic types of fuel, including the low grade ones. Thereby interest is raised to such a source of hydrocarbons as combustible shales. Combustible shales appear to be one of the highest-potential types of organic raw materials, which may offset and in future even substitute oil products and gas. The paper is investigating behavior and structure of combustible shales during heat treatment in order to identify their possible industrial applications. A synchronous thermal analysis has been held, chemical composition of combustible shales’ mineral fraction and optimal conditions for shale fines briquetting have been determined.
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Date submitted2014-12-20
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Date accepted2015-02-05
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Date published2015-12-25
Synergetic changes of tribochemical properties in the heterogeneous systems containing surface modified metals
- Authors:
- A. G. Syrkov
In the article tribochemical properties and synergetic effects in lubricants with metal addi-tives, characterized by surface modifcations, have been analysed. The priority results of measur-ings friction coefficient (f) and friction force (F fr) are given for heterogeneous systems in the form of И-20 oil with solid Al-additives, contatiing dispersed aluminium, with surface-modified triamon (Т), alkamon (A) and ethylhydridsiloxane according to various programs. It has been educed that with all other things being equal, triamon underlayers introduction into Al-additives with the external chemisorpted ethylhydridsiloxane layer results in the decrease of F fr and f in the system in proportion to the Т-underlayer number reduction from three to one. It has been discovered that the use of low-molecular Т-underlayer in Al-additives is a delicate method of summand value regulation (from 10,8 to 13,2 Н), accountable for intermolecular forces in the boundary fritction equation in the tribological pair applied.
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Date submitted2009-10-10
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Date accepted2009-12-02
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Date published2010-09-22
Deformational precursors of technogenic earthquakes in mining the hydrocarbon deposits
During monitoring since 2005 to 2008 at the Astrakhan gas-field it has been recorded three technogenic earthquakes. Results of geodetic levelling for the given period allow to approve that seismic event is preceded by raisings of a surface and its subsequent subsidence as a its result of unloading. That allows to use geodetic levelling for the forecast of technogenic seismic phenomena for oil and gas fields.
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Date submitted2009-10-13
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Date accepted2009-12-14
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Date published2010-09-22
The evaluation of geodynamic consequences оf long-term exploration of lower cretaceous sediments at the Yamburg oil-gas condensate field with join of additional wells
Within the framework of the engineering design of the join up of additional wells of Lower Cretaceous sediments at the Yamburg oil-gas condensate field the evaluation of geodynamic consequences of long-term exploitation of the mentioned field was performed, as well as the hazardous geodynamic process permanent survey program was developed.
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Date submitted2009-10-20
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Date accepted2009-12-11
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Date published2010-09-22
Monitoring of deformation processes of the earth surface with methods of differential interferometric treatment of radar data
- Authors:
- A. A. Krivenko
- Yu. A. Kashnikov
The Differential Interferometry SAR (DInSAR) has recently become one of the most popular methods to reveal and analyze the subsidence of the ground. This method is considered by researchers to be well suited to solve a problem of small relative ground shifts survey applying the short (centimeter) radio waves.
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Date submitted2009-07-17
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Date accepted2009-09-06
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Date published2010-04-22
Hydrogeomechanical processes in flooding of mines
- Authors:
- Yu. A. Norvatov
- I. B. Petrova
Hydrodynamic and hydrogeomechanical processes which may occur during flooding of coal mines are considered. Original scheme – model of strain state of waterbearing undermined massif for estimation of uplift of earth surface was suggested.