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Анастасия Литвинова

Hydraulic transportation of thickened tailings of iron ore processing at kachkanarsky gok based on results of laboratory and pilot tests of hydrotransport system

Записки Горного института
The object of study is the system of hydrotransport of iron ore processing tailings at JSC «EVRAZ Kachkanarsky GOK». The aim of the work was to determine the parameters of the hydraulic transport of tailings of the iron ore enrichment at weight concentrations of the solid phase from 30 to 70 % and to develop recommendations for the industrial operation of hydraulic transport systems of highly concentrated slurries of the Tailing Facilities of the Kachkanarsky GOK. Laboratory studies of the parameters of hydrotransport of thickened tail pulps were carried out with the development of a calculation method; pilot tests of the hydrotransport system under the conditions of the Tailing Facilities of the Kachkanarsky GOK. It has been established that using polyurethane coatings on the inner surface of the slurry lines significantly (1.75 times) decrease the specific pressure loss on the hydrotransport of thickened fluids. This allows to significantly increase the range of transportation for placing tailings in the distant parts of the storage zone. The introduction of research results is in the project of reconstruction and development of the tailing facility of the TF of the Kachkanarsky GOK for the period 2018-2020. It is proposed to use the results of work in the project of reconstruction of the hydraulic transport system at the TF of the Kachkanarsky GOK by switching to the hydraulic transport of slurries thickened to weight concentrations of 35-40 % in the slurry pipes with an internal polyurethane coating, which will ensure energy saving in the hydraulic transport process.

Multivariance of the velocity model for structural plotting based on seismic and borehole data

Записки Горного института
The paper discusses the peculiarities of structural modelling (forecast of the depths of the reflecting horizons) based on the seismic and drilling data system. Seismic data are represented by vertical time values and the stacking velocity of borehole data that are the depth marks of the reflecting horizons. Vertical time and the depth of the reflecting horizons are bound by the equation of average velocity but the average velocity is not determined in a seismic experiment, therefore an issue of choosing a velocity model of a complex natural object arises. The task of structural modelling is solved by the selection of formal expressions containing correlations between the parameters of the underlying model and kinematic parameters of the wave field. The optimal decision on model selection is determined by the minimum discrepancy between the predicted and actual values of the depth of the sample boreholes. A practical example shows possible variants of the interpretation model. An inverse kinematic problem on converting the vertical time of the reflected waves at the depth of horizons is solved in each production report on the results of seismic work and is probably the most common objective of seismic exploration. Considering the variety of research objects and the apparent obviousness of the solution, this topic is underrepresented in scientific literature.

Environmental geochemical assessment of technogenic soils

Записки Горного института
The purpose of this study was to obtain diagnostic features and criteria for the distribution of heavy metals in technogenically altered soils in the area of industrial facilities, depending on their altered geochemical properties, which make it possible to fix chemical elements in landscapes (the formation of geochemical barriers). On the basis of the geoecological assessment, disturbance of the soil buffer properties, which is reflected in the ionic composition change, alkalization, pH increase, and sulfate-chloride salinization have been revealed. This forms the heavy metals alkaline barrier. For example, in case of Cu, Pb, Zn, and N, it contributes to their accumulation and subsequent concentration in the soil layer due to the exchange interactions between chemical elements and Na+, K+, Ca2+ cations. Soil saturation with sulphates also increases the probability of metals demobilization in the soil layer. It has been shown that intra-sectional soil migration of oil products (one of the most common pollutants of industrial areas) and chemical elements occurs at a depth of 30-50 cm, where the oil products based on a clay sorption layer form a technogenic barrier. The direct correlation between the oil content in the soil and the amount of toxic sulphate and chloride salts was found. The set of identified factors forms technogenic geochemical barriers in the industrial production area, on which pollutants and chemical elements, including heavy metals, are demobilized. The revealed effects are the rationale for creating artificial geochemical barriers on the migration path of both pollutants and valuable components with the aim of their subsequent extraction from the soil when developing an appropriate extraction method.

Development of vibroacoustic module for fine filtration of drilling muds

Записки Горного института
The issue of drilling mud multiple use is problematic. To reuse, the solution must be efficiently cleaned from solid particles according to the class of 0.04-0.07 mm. An analysis of existing technologies and equipment has shown that drilling mud regeneration schemes are rather difficult to operate and expensive. In world practice there has been a tendency to create universal equipment, which allows most complete cleaning cycle for a drilling mud in fine grades. The paper proposes an innovative vibroacoustic module for cleaning drilling muds from sludge. The creative element of the proposal is the impact of vibroacoustic oscillations on the drilling mud passing through the mesh element. At the same time, specific effects arise around the mesh, which increase the productivity and efficiency of the process. The design of the vibroacoustic apparatus and the principle of its operation are presented. An important element of the proposal is that the oscillation is created by pistons interconnected by rods and located on opposite sides of the mesh. This dipole system provides the excitation of variable pressures of different polarity before the mesh and after it. The results of industrial tests of the vibroacoustic module when servicing the BU-75-BrE drilling rig are presented. The dependence of the installation performance and efficiency on the amplitude of oscillations was found. The optimal dynamic range of exposure (from 5.5 to 6.5 mm) was determined. Analysis showed that in the composition of the cleaned drilling mud, the maximum particle size of the solid phase did not exceed 0.04 mm. The conducted industrial tests confirmed the possibility of using the vibroacoustic module for cleaning the washing fluid and developing a pit-free drilling technology on its basis.

Natural ventilation of gas space in reservoir with internal floating roof

Записки Горного института
The article deals with safe operation issues of vertical steel reservoirs with an internal floating roof when storing volatile oil products. The purpose of the work is to study the influence of ventilation openings area and wind speed on the duration of explosive state of vertical reservoirs with an internal floating roof. The influence of ventilation pipes' dimensions and the wind speed on the duration of explosive state of the reservoir has been studied. Method for calculating this time is proposed. It is shown that natural ventilation of the reservoir gas space is caused by the effect of two forces, which are formed due to: 1) the density difference between the vapor-air mixture in the reservoir and outside air; 2) wind pressure occurring on the roof of the reservoir. An algorithm for calculating the duration of reservoir being in an explosive state with wind pressure and no wind is obtained. The greater the difference in geodetic marks of the central and peripheral nozzles, the more efficient the ventilation. This distance will be greatest if the lower ventilation pipes are located on the upper belt of the reservoir or the reservoir is equipped with an air drain. Increase in wind speed of more than 10 m/s does not significantly affect the duration of the reservoir being in an explosive state. Increasing the diameter of the central nozzle from 200 to 500 mm can significantly reduce the duration of the reservoir degassing in windless weather.