Purpose. Determination and substantiation of the hydromechanization technologies parameters and the hydraulic transport operation modes for mining the technogenic deposits formed as a result of the enrichment waste storing in tailing dumps of mining and processing enterprises. Methods. A comprehensive multi-stage analytical approach has been used in a paper when performing research. Initially, in order to substantiate the hydromechanization technologies parameters, the parameters of the pulp-preparation unit have been analytically determined in this paper, which are limited by the value of the upper dam edge, taking into account the types of hydraulic mixture. At the second stage, dependences have been set for calculating the critical velocity of hydraulic transporting the pulps with different concentration (low, mean, and high). The next research stage was to determine the head and rate specification (HRS) of the hydrotransport pipeline and the required capacity of the hydraulic mixture, which will enable substantiating the parameters for the corresponding mining complex in the technogenic deposits development. Findings. A critical pipeline diameter has been set with the prescribed parameters of the mining complex and the adopted pulp preparation system. Dependences have been found for calculating the critical velocity of hydraulic transportation of mean-and highly-concentrated pulps. The head and rate specifications have been determined of the tailing hydrotransport pipeline. Originality. For the first time it has been revealed that the critical diameter value is determined by the product of two termsthe first one takes into account the effect of the mining complex productivity, and the secondthe dependence on the pulp preparation system parameters. This makes possible to control the parameters and modes of hydromechanization technologies when mining technogenic deposits formed as a result of storing the enrichment waste in tailing ponds. Practical implications. The "Recommendations for substantiating the parameters of the processes of accumulating capacity restoring of a pond with the use of hydromechanization devices" and "Methods for calculating the parameters for hydraulic transportation of highly-concentrated hydraulic mixtures", have been developed, which may be useful for design organizations and mining-metallurgical enterprises to provide additional volumes of raw material output and increase the tailing ponds lifetime.
Purpose. Study of the plasma flow interaction with the borehole surface in the process of its thermal reaming for determination of transient temperature distribution along the borehole surface and the average coefficient of heat transfer from the plasma flow to the borehole surface. Methods.Experimental study of the plasma flow interaction with the flange union with internal lateral surface simulating the rock surface in a borehole has been carried out. The essence of the experimental study is in measuring temperature of the flange union external side while the plasma flowing inside the flange union. To measure temperature on the external surface of the flange union, a chromel-alumel thermocouple with thermoelectrodes of 1.2 mm in diameter was used. In experimental research, plasma flows out through a nozzle directly to the flange union made of copper. The parameters of the flange union and the nozzle of plasmatron are geometrically similar.Findings. Experimental data are processed as a relationship between the temperature of the copper flange union lateral surface, i.e. borehole surface, and the time of the copper flange union heating by the heat carrier. Experimental data are processed as a dependence of temperature of the tin pipe side surface, i.e. surface of the borehole, on the location of temperature measurement point along the tin pipe and the time of the tin pipe heating by the heat carrier.Originality. Physical simulation modeling of the heat carrier (low temperature plasma) flow interaction with the borehole surface simulated by the copper flange union and the tin pipe in a certain range of geometrical parameters of the copper flange union, tin pipe and the plasmatron nozzle as well as thermophysical properties of the heat carrier assumed in accordance with geometrical similarity to the technological and design parameters of the plasmatron and borehole diameter before the beginning of thermal reaming process.Practical implications. Methodology of experimental research of the heat carrier (low temperature plasma) flow interaction with the borehole surface that was simulated by the copper flange union of the tin pipe is developed. The results of the influence by high-temperature heat carrier jets on the processes of fragile rock destruction are rather useful in the borehole drilling processes.
The method of determination of parameters of hydrotransport of solid polydisperse materials in vertical pipelines is offered. The reasons of discrepancy between estimated and observed data when using A. Smoldyrev’s method for calculation of hydraulic gradient and critical velocity in vertical steel pipelines are analysed. Particularly non-applicability of Velicanov principle to hydrotransport of solid materials in vertical pipelines is proved and contribution of particles fall velocity to the value of complementary hydraulic gradient in vertical pipelines is estimated. Suggested formulas for calculation of hydraulic gradient and critical velocity in vertical pipelines are multipurpose because they may be used for calculation of hydrotransport parameters in steel and polymeric vertical pipelines with using of friction reducing agents and without it. The method for parameters calculation of solid materials hydrotransport in vertical polymeric pipelines is first offered. Elaborated formulas ensure also increasing of accuracy of calculations.
The paper describes the ways to extend the service life of tailings storage facilities by restoring their accumulation capacity. Analysis of the state-of-the-art experience in tailings management is provided. Restoring is carried out due to the following: storing of waste as paste-like slurry; raising embankment; intensifying wastewater treatment process in ponds by means of coagulation agents; selection of adequate alluviation maps mode; specifying parameters of surface and underwater alluvial beaches; implementing the separate storage of solid-phase fractions; preliminary pulp clarification in alluviation maps before supplying it to the pond. Due to the long length of the hydrotransport lines, the use of paste thickeners in the mining and processing plants of Kryvbas is impossible. These technologies are implemented at new storage facilities where waste is placed in the first tier. The aim of this study is to determine and substantiate parameters of hydro-mechanical systems during the operation of tailing facilities with temporary clarifiers. The study for the first time established relationship between the temporary pond operation time. There are such parameters as concentration and consumption of slurry, initial depth of the pond filling, barrier dam height and the length of alluvial front.
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