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Date submitted2020-05-05
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Date accepted2020-05-24
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Date published2020-06-30
Justification of stripping and development of a modular mine site for a combined coal mining method in Kuzbass on the example Baikaimskaya mine site
- Authors:
- Roman I. Shishkov
- Valerii A. Fedorin
The article considers one actual method for development coal deposits in the Kuzbass by open-underground mining. The scientific and practical advantages of the proposed method due to the use of common infrastructure of coal mine and a modular mine site (subsequently transformed into a mining and technological structure operating according to the mine – longwall scheme) are presented. Currently, a development strategy for Kuzbass until 2035 has been developed. As part of the strategy, a draft program for subsoil use is being formed in the coal industry department. The program should take into account all the positive and negative aspects associated with coal mining in cities and municipal areas and also their prospects. In the Kuznetsk coal basin, 42 mines and 52 opencast mines are mining, of which 12 enterprises use partially unified infrastructure. According to the results of open-underground mining work conducted by the laboratory of the Institute of Coal and Coal Chemistry of the Siberian Branch of the Russian Academy of Sciences (Institute of Coal SB RAS), the list of sites includes favorable mining and geological conditions with incidence angles of up to 18 degrees. As open-pit coal production increases, many sites encounter such a parameter as maximum allowable (boundary) strip ratio. At the stage of preparing the feasibility study for the development of a coal deposit, this coefficient is calculated first of all, since duration of enterprise’s work and its economic component depend on it. In order to increase parameters, it is necessary to carry out transition from open works to underground. As a result, coal mine will not work at a loss, providing production with an economically disadvantageous strip ratio.
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Date submitted2015-12-13
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Date accepted2016-02-23
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Date published2016-12-23
Properties isotropy of magnesium alloy strip workpieces
- Authors:
- R. Kavalla
- V. Yu. Bazhin
The paper discusses the issue of obtaining high quality cast workpieces of magnesium alloys produced by strip roll-casting. Producing strips of magnesium alloys by combining the processes of casting and rolling when liquid melt is fed continuously to fast rolls is quite promising and economic. In the process of sheet stamping considerable losses of metal occur on festoons formed due to anisotropy of properties of foil workpiece, as defined by the macro- and microstructure and modes of rolling and annealing. The principal causes of anisotropic mechanical properties of metal strips produced by the combined casting and rolling technique are the character of distribution of intermetallic compounds in the strip, orientation of phases of metal defects and the residual tensions. One of the tasks in increasing the output of fit products during stamping operations consists in minimizing the amount of defects. To lower the level of anisotropy in mechanical properties various ways of treating the melt during casting are suggested. Designing the technology of producing strips of magnesium alloys opens a possibility of using them in automobile industry to manufacture light-weight body elements instead of those made of steel.
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Date submitted2014-10-15
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Date accepted2014-12-14
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Date published2015-08-25
Formiing of structure and properties of sheet strips from magnesium alloys in the conditions of twin roll casting process
- Authors:
- R. Kavalla
- V. Yu. Bazhin
In this article the problem of receiving high-quality cast strips from the magnesium alloys received by units of twin roll casting process in the combined methods is discussed. Production of sheets from magnesium alloys combination of casting and rolling at continuous giving of liquid melt to the rotating rolls is perspective and more economic method. Features of crystallization of magnesium alloys of AZ31 and AZ61 in a gap of rolls crystallizers depending on heat exchange conditions at change of technological parameters are considered. Due to impact on melt in forming system it is possible to provide formation of equal fine-grained structure of sheet hire without superficial defects. Development of the production technology of sheets from magnesium alloys creates possibility of their use of automobile branch as the facilitated details of bodies instead of the knots made of steel.