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Date submitted2022-02-24
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Date accepted2022-05-25
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Date published2022-07-26
Litsa uranium ore occurrence (Arctic zone of the Fennoscandian Shield): new results of petrophysical and geochemical studies
Mineralogical, petrophysical and geochemical studies have been carried out to determine the sequence and formation conditions of uranium mineralization within the Litsa ore occurrence (Kola Region). Mineralogical studies show the following formation sequence of ore minerals: uraninite – sulfides – uranophane, coffinite, pitchblende. Two stages of uranium mineralization are distinguished: Th-U (1.85-1.75 Ga) and U (400-300 Ma). The distribution of physical properties of rocks in the area is consistent with the presence of two temporal stages in the formation of mineralization with different distribution and form of uranium occurrence in rocks. The factors that reduce rock anisotropy are the processes of migmatization and hydrothermal ore mineralization, which heal pores and cracks. Fluid inclusions in quartz studied by microthermometry and Raman spectroscopy contain gas, gas-liquid and aqueous inclusions of different salinity (1.7-18.4 wt.% NaCl-eq.). According to homogenization temperatures of inclusions in liquid phase, the temperature of the Paleoproterozoic and Paleozoic stages of uranium mineralization at the Litsa ore occurrence is ~ 300 and 200 °С, respectively. Correlations of the spatial distribution of elastic anisotropy index with an elevated radioactive background allow using this petrophysical feature as one of the prognostic criteria for uranium and complex uranium mineralization when carrying out uranium predictive work.
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Date submitted2020-05-08
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Date accepted2020-06-12
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Date published2020-12-29
Gas-dynamic roof fall during the potash deposits development
In the development of practically all potash salt deposits, the study of gas-dynamic phenomena (GDP) is one of the most difficult tasks to ensure mining safety. Sudden salt and gas outbursts, dynamic breakdown, which are accompanied by intense gas release and possible broken rock carry-over into the mine workings, are associated with GDP. Geological preconditions for the GDP development are often the layered structure of the salt rock mass, the presence of interlayers and layers of salt clays. For the conditions of the Usolsky potash plant mine, complex studies of factors that characterize the possibility of gas-dynamic roof fall of the stoping rooms were carried out. In mine studies, free gases pressure and the initial velocity of gas release in the rocks of the roof workings were determined. The obtained experimental estimations were used as a parametric basis for mathematical modeling of geomechanical processes under conditions of a near-contact accumulation of free gas. The deformation of a layered salt mass produced by a room development system was described by the model of an ideal elastic-plastic medium with internal friction. The parabolic envelope of Mohr circles was used as a plasticity criterion in the compression area. In the numerical implementation, the deformation of clay contacts was modeled by Goodman contact elements. Based on the results of multivariate numerical calculations, it is established that the main factors determining the possibility of implementing GDP are the additional gas pressure at the contact, the width of the workingspan, and the distance from the roof to the first gas-containing contact. With multi-level lamination of roof rocks, there is a danger of large sources of GDP formation and the mechanism of successive fall of layers in an instant mode is implemented.
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Date submitted2019-03-25
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Date accepted2019-05-23
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Date published2019-08-23
Assessment of Rock-Burst Hazard in Deep Layer Mining at Nikolayevskoye Field
The paper presents results of conducted research using regional and local methods of forecast and control over geomechanical state of the rock mass at burst-hazardous Nikolayevskoye field, located in a geodynamically active region. The study subject is the ore mass of Nikolayevskoye field, characterized by man-induced and tectonic disturbances and high geodynamic activity. The aim of research was practical implementation of methods and instruments of forecast and control over geomechanical state of the burst-hazardous rock mass and safety improvement of mining operations. Exploitation practice of burst-hazardous fields demonstrates that forecast accuracy of hazardous rock pressure demands cutting-edge multi-level systems, where local methods and tools complement regional ones. A regional forecast of rock-burst hazard at Nikolayevskoye field was performed by means of seismoacoustic method using automated control system for rock pressure (ACSRP) «Prognoz-АDS». Local forecast was carried out using «Prognoz-L» device, geophysical (sample disking) method and visual observations of dynamic pressure manifestations in the mining tunnels. Quality assessment of stress-strain and burst state of the rock mass was performed using specialized software «PRESS 3D URAL». Integration of engineering and geomechanical data in the process of conducting research guarantees a relevant assessment of rock-burst hazard in various areas of the field at various stages of its development. Practical verification of the system, where local methods and tools complement regional ones, demonstrated satisfactory results at Nikolayevskoye mining plant, which makes it recommendable for other mining facilities extracting ore at great depths under similar conditions of active geodynamic processes.
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Date submitted2019-03-05
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Date accepted2019-05-03
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Date published2019-08-23
Efficiency Estimation of the Single- and Multicomponent Anti-hydrate Reagents
- Authors:
- N. A. Shostak
- E. P. Zaporozhets
Different types of technological and technical problems in the oil, gas and chemical industries are connected with the hydrate formation process and with the using of anti-hydrate chemicals. That is why, it is necessary to estimate thermobaric ranges within which reagents does not let hydrate to grow or is their dissociation. Also, to estimate anti-hydrate influence we need to determine the chemicals’ anti-hydrate efficiency and chose the best one. They make the reagents consisting of several chemical components depending on the purpose of their application – for prevention of formation and (or) elimination of hydrates. It demands calculations of the optimum concentration and expenses and also the intensity (speed) of hydrates dissociation causing with the reagents. The analytical method of the anti-hydrate chemical reagents efficiency determination containing one or several components from different classes of chemical compounds – alcohols, salts, acids, compounds of nitrogen and oxygen – is presented in this paper. With its help it is possible to define decrease in temperature of hydrate formation from reagents influence, to count key parameters of reagents anti-hydrate efficiency depending on component compositions of hydrate gas and a phase condition of a hydrate-gas system, to select types of chemical components and their quantity in multicomponent reagents, i.e., to make new compounds. The method can be used for express assessment of anti-hydrate chemical reagents efficiency on criteria sign for practical application in oil, gas and processing industry.
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Date submitted2015-12-24
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Date accepted2016-02-04
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Date published2016-12-23
Geodynamic methods for assessing methane distribution in bituminous coal deposits and measures to intensify methane fluxes during mine gas drainage
- Authors:
- E. V. Goncharov
- S. V. Tsirel
This paper explores states of methane within the coal bearing stratum and shows heavy dependency of the intrastratal gas migration on the forms of porous space and petrographic properties of coal. The adsorbed methane is found to be predominant in the coal of Kuznetsk Basin. Different forms of coal diffusion and filtration are described revealing their dependency on geological and thermodynamic conditions. The paper provides justification for the primary focus on geodynamic processes when designing gas drainage systems and applicability of morphometric methods and remote sensing data for their identification. The significance of researches into the processes activating exothermic reactions resulting in methane transition to free state is explained. The paper presents the results of using seismic-acoustic stimulation techniques as one of the practical approaches to addressing this issue. Results of successful industrial testing have been compared with the results of numerical modelling of stress-strain state, which can also be managed through seismic-acoustic stimulation.
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Date submitted2009-10-14
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Date accepted2009-12-11
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Date published2010-09-22
Investigation of present-day stress-strain state of rock mass by the results of observations at geodynamic polygons
- Authors:
- S. N. Savchenko
- E. V. Kasparyan
- Yu. G. Smagina
The methods are suggested for treatment of the results of optical distance and levelling measurements at the underground geodynamic polygons involving in their calculation the tensors of additional stresses and deformations, component of rotation and specific energy of deformability. As an example, consideration is given to changes in time of movements, deformations and specific energy of deformability at one of geodynamic polygons of the Kola peninsular.
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Date submitted2009-10-18
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Date accepted2009-12-10
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Date published2010-09-22
Factors of geodynamic risk in exploration оf the Bovanenkovsk oil-gas condensate field аt the Jamal peninsular
Geological-structural peculiarities of territory are considered; factors of human impact on geological environment and their geoecological consequences while field development are systematized; the concept of geodynamic monitoring as a tool of maintenance of operational reliability of gas producing facilities is offered.
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Date submitted2009-07-21
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Date accepted2009-09-27
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Date published2010-04-22
Study of gas-and geodynamic state of technogenically changeable coal rock mass
- Authors:
- A. D. Ruban
Intensification and concentration of the mining works increases substantially the risk of geo- and gasdynamic effects arising within the coal mines. Herewith are presented the results of the analytic and experimental studies on stress-strain state of rock mass due to technogenic impact. Under such conditions a potential avalanche destruction of coal rock mass may occur. Some criteria for evaluation of gas-dynamic danger for rock mass, for active stopes and development faces are given. The computer-aided system for monitoring of hazard of gas- and geodynamic phenomena in mines is suggested.
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Date submitted2009-07-23
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Date accepted2009-09-09
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Date published2010-04-22
Physical modeling of energy exchange in rock mass
- Authors:
- E. V. Lodus
- E. V. Goncharov
The cause of manifestation of dangerous dynamic phenomena, such as rock bursts, earthquakes, etc., appears to be the energy exchange in rock mass. The inaccessibility of rock mass for carrying out the full-scale observations has stimulated to study this problem with using the methods of laboratory modeling. Description is given to the substance of energy exchange in situ, the principles of its physical modeling in the laboratory, to the test equipment as well as to some results of our investigations.
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Date submitted2009-07-28
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Date accepted2009-09-30
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Date published2010-04-22
Organization and conduct of monitoring of geodynamic processes at the Grushovaya transshipment oil base of the Chernomortransneft Co
- Authors:
- A. P. Skakun
The complex of geophysical methods and equipments for continuous and periodic monitoring of the influence of present-day geodynamic processes on support and rocks along the route of technological tunnel of3300 mlong within the zone of high seismicity has been developed.
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Date submitted2009-07-07
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Date accepted2009-09-04
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Date published2010-04-22
Application of geodynamic polygons for monitoring of ground deformations while exploitation of gas and oil fields
The main aims and problems of geodynamical monitoring of oil and gas fields are considered. It’s proved that monitoring of deformations of long-term oil and gas fields becomes really actual to secure stable oil and gas production and transporting. Basic criteria of geodynamical polygon creation and general requirements for gas and oil fields monitoring are adduced in this work. For practical creation of geodynamical polygons one indicated equipment, methods and content of work with phases.
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Date submitted1958-03-11
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Date accepted1958-05-28
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Date published1958-05-09
ТРАНСГРЕССИВНЫЕ И РЕГРЕССИВНЫЕ ЯВЛЕНИЯ В ЦИКЛАХ УГЛЕНОСНЫХ ФОРМАЦИЙ
- Authors:
- Unknown
Вопрос о трансгрессивных и регрессивных явлениях при накоплении осадков вступил в новую фазу. Это произошло благодаря изучению угленосных формаций с учетом цикличности их строения. В литологических работах по Кузнецкому, Карагандинскому и другим бассейнам, а особенно по Донецкому, выяснилось значение осадочных циклов, состоящих из регрессивных и трансгрессивных частей. В дальнейшем было установлено, что регрессия не повторяет в обратном порядке пород и фаций трансгрессивной части цикла. Она характеризуется рядом фаций с особыми признаками, если даже они развиваются на тех же глубинах и тех же расстояниях от берега, что и трансгрессивные фации. Соответственные признаки пород также несут на себе черты отличий, которые все более и более выявляются.