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Date submitted2021-03-24
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Date accepted2022-12-15
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Date published2023-08-28
Composite model of seismic monitoring data analysis during mining operations on the example of the Kukisvumchorrskoye deposit of AO Apatit
Geomechanical monitoring of the rock mass state is an actively developing branch of geomechanics, in which it is impossible to distinguish a single methodology and approaches for solving problems, collecting and analyzing data when developing seismic monitoring systems. During mining operations, all natural factors are subject to changes. During the mining of a rock mass, changes in the state of structural inhomogeneities are most clearly manifested: the existing natural structural inhomogeneities are revealed; there are movements in discontinuous disturbances (faults); new man-made disturbances (cracks) are formed, which are accompanied by changes in the natural stress state of various blocks of the rock mass. The developed method for evaluating the results of monitoring geomechanical processes in the rock mass on the example of the United Kirovsk mine of the CF AO Apatit allowed to solve one of the main tasks of the geomonitoring system – to predict the location of zones of possible occurrence of dangerous manifestations of rock pressure.
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Date submitted2022-04-14
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Date accepted2022-07-21
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Date published2022-07-13
Mullite production: phase transformations of kaolinite, thermodynamics of the process
The growing demand for mullite raw materials, which meet industrial requirements originates the search for new and alternative sources, as well as efficient technologies for obtaining the target products (nanocomposites). The article suggests a method for obtaining mullite from kaolinite experimentally (Vezhayu-Vorykvinsky deposit, Russia). Structural kaolinite transformations (Al-Si-O-Me system), mineral phases transformations, and thermodynamics of the process have been studied. Based on the estimation of the thermodynamics of the reactions, the preferable reaction of mullite formation was determined. The article shows, that formation of the target product, mullite nanocomposite, has several intermediate phases (metakaolinite, pseudomullite). The transformations of the initial kaolinite structure include the removal of structural water and separation of the silica-oxygen tetrahedral and alumina-oxygen octahedral layers, the decomposition into free oxides, breaking of bonds between the silica-oxygen tetrahedrons and the partial increase in the coordination number of aluminium ions, the formation of mullite and cristobalite from free oxides. The proposed approach controls the ratio of Al 2 O 3 and SiO 2 phases at certain stages, which will further improve the mechanical and other properties of the matrix of the obtained raw materials for the target prototypes of industrial products.
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Date submitted2021-02-20
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Date accepted2021-05-21
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Date published2021-09-20
Analysis of the screw press mouthpiece parameters for 3D extrusion of peat pieces of tubular type
The results of theoretical and experimental studies on the creation of a screw press composite mouthpiece screw press for 3D-forming of peat pieces of a tubular type in the field for intensifying the process of field drying of material in a complex mechanized pit are presented. The main purpose of the study was to substantiate the geometric and design parameters of the screw press composite mouthpiece of the spread machine for the production of peat-agglomerated products of the tubular type. The parameters of the mouthpiece are selected based on the geometric characteristics of the peat pieces. An increase in moisture loss during drying of peat-agglomerated products is provided by forming a peat piece in the form of a thick-walled pipe made of a peat raw materials composed of low and high decomposition degrees in a ratio of 1:3. Additive production of polymer-fiber peat composites by extrusion allows to produce products with improved mechanical properties in comparison with non-reinforced raw materials. The vertical arrangement of the peat tubular piece on the drying field allows to increase the loading of the field area by 10 %, increase the convective heat supply to the piece and reduce the contact coefficient of the piece with the field by three times in comparison with the peat spreading of the pieces in the form of a horizontal tape. Based on the analysis of the shape and size of the agglomerated products, the design of a screw press composite mouthpiece consisting of two conditional molding zones of various configurations has been developed. The article presents a parametric analysis of the volumetric productivity of a screw press with a composite mouthpiece of a tubular type, the energy intensity of mechanical processing is determined, the degree of mechanical processing of peat raw materials is estimated with the optimization of the screw parameters for the production of agglomerated products of a tubular type.
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Date submitted2016-09-06
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Date accepted2016-11-15
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Date published2017-02-22
Modelling of fiberglass pipe destruction process
The article deals with important current issue of oil and gas industry of using tubes made of high-strength composite corrosion resistant materials. In order to improve operational safety of industrial pipes it is feasible to use composite fiberglass tubes. More than half of the accidents at oil and gas sites happen at oil gathering systems due to high corrosiveness of pumped fluid. To reduce number of accidents and improve environmental protection we need to solve the issue of industrial pipes durability. This problem could be solved by using composite materials from fiberglass, which have required physical and mechanical properties for oil pipes. The durability and strength can be monitored by a fiberglass winding method, number of layers in composite material and high corrosion-resistance properties of fiberglass. Usage of high-strength composite materials in oil production is economically feasible; fiberglass pipes production is cheaper than steel pipes. Fiberglass has small volume weight, which simplifies pipe transportation and installation. In order to identify the efficiency of using high-strength composite materials at oil production sites we conducted a research of their physical-mechanical properties and modelled fiber pipe destruction process.