-
Date submitted2023-10-28
-
Date accepted2024-11-07
-
Date published2025-02-25
Radiation characteristics of coals at different stages of metamorphism
The formation of deposits and subsequent metamorphic processes that affect concentrations of radioactive elements in coal can indicate ongoing geological activities, therefore, analyzing trends in the radiation characteristics of coal throughout the metamorphic series is highly relevant. The aim of this work is to experimentally evaluate the radiation characteristics of different coal ranks (metamorphic stages) using thermoluminescent (TL) dosimetry and beta activity measurements, and to identify correlations between these radiation characteristics and data obtained from technical, elemental, and thermogravimetric analyses, as well as mass spectrometric and electron paramagnetic resonance spectroscopy (EPR) measurements. For dosimetric measurements that indirectly characterize the content of radionuclides in coal, a modified dosimetric complex and original soil-equivalent thermoluminescent detectors based on SiO2 were used. The analysis of the obtained results supports the use of TL studies to determine the ash content of coals at low and medium stages of metamorphism (coal rank B→G), while indicating that this method is not feasible for coals at higher stages of metamorphism. The correlation dependencies in the metamorphism series suggest abrupt change in the conditions of coal formation during the time range corresponding to transformation from high to low volatile bituminous coals (coal rank G→Zh→K). These abrupt changes in regional metamorphism conditions (time, temperature, pressure, oxidation-reduction conditions) are confined to the boundary of the Permian and Triassic periods (~250 million years ago), during which both the transformation of existing coal deposits and the formation of new deposits occurred.
-
Date submitted2024-04-11
-
Date accepted2024-06-03
-
Date published2024-07-04
Assessment of the efficiency of acid mine drainage purification (using the example of copper-pyrite mines in the Middle Urals)
According to the results of the anti-rating of regions with extreme pollution of watercourses in the Sverdlovsk region, the largest number of polluted rivers has been recorded in recent years – more than a quarter of all high and extremely high pollution. One of the sources of pollution of natural water bodies in the Middle Urals are closed and flooded copper-pyrite mines, where acidic mine drainage continue to form and unload to the surface. Several of them have organized collection and a two-stage acidic drainage purification system, including neutralization with lime milk and settling in a clarifier pond. Despite the identical schemes, different indicators of pollutants are recorded during discharge into water bodies. The aim of the work is to evaluate the effectiveness of the applied acid mine drainage purification system and identify the parameters affecting the quality of treated mine water. Laboratory studies were performed using methods of flame emission spectrometry, flame atomic absorption, atomic absorption spectrometry, mass spectrometry with ionization in inductively coupled plasma, potentiometric, etc. It has been established that the existing mine drainage purification system at the Degtyarskii mine makes it possible to significantly reduce the concentrations of most toxic components of mine waters to almost standard values. At the Levikhinskii mine, the multiplicity of exceeding the maximum permissible concentrations reaches hundreds and thousands of times. To achieve a higher degree of purification, it is necessary that the duration of passive purification is sufficient for the reactant to interact with acidic waters. However, to ensure this possibility, it will require the creation of a cascade of ponds with an area of several thousand hectares. If the current two-stage system is quite effective for the Degtyarskii mine, then for Levikhinskii it is necessary to switch to the use of more modern systems, including three stages of purification.
-
Date submitted2023-06-21
-
Date accepted2023-12-27
-
Date published2024-12-25
Peculiarities of formation, isomorphism and geochemistry of trace elements of sphalerite and wurtzite unusual varieties from the Goniatite occurrence (Pai-Khoi Ridge, Nenets Autonomous District)
A unique Mn-, Cd-bearing sphalerite from quartz-calcite veins in the coal-bearing series (Visean C1v) marine sediments in a 50 km segment of the middle course of the Silova-Yakha River in the Arctic zone of the European part of Russia (Pai-Khoi Ridge) has been studied. The veins have a conformable and cross-cutting occurrence in two types of rocks: gray limestones and black siliceous-carbonaceous shales, the area is known as the Goniatite occurrence. The sulfide content in vein samples ranges from 0.1 to 2 vol.%. The chemical composition of 27 monomineral samples of Mn-, Cd-bearing sphalerites was studied, 82 points were analyzed. Correlations between typomorphic elements-impurities were revealed and correlation matrix was constructed. Cu, V, Ga, In, Sn, As, Sb, Bi, Pb, Tl, Se, Ag, Au, Ni are positively correlated with each other; Cd, Mn and Ge are negatively correlated with each other. The hydrothermal fluid involved in crystallization of sphalerite is characterized by low temperature (164-211 °С) and average salinity of 5-6 wt.% eq. NaCl. An updated “portrait” of typomorphic features (composition and properties) of sphalerite of the Pai-Khoi province was obtained. The features allowing to determine the type of impurity entering the sphalerite structure – in the form of isomorphic impurity or in the form of microinclusions of paragenetic association minerals – have been established. Submicron inclusions of sulvanite and colusite, invisible by other methods, were detected in sphalerite (by LA-ICP-MS method).The cathodoluminescence data of sphalerite from the Pai-Khoi province were typified. In contrast to other provinces, ZnS crystals here are characterized by almost complete absence of isomorphic iron. This allowed us to study pure isomorphism schemes of ZnS↔MnS, ZnS↔CdS, namely cathodoluminescence and other types of luminescence. The presence of a rare wurtzite-4H polytype in assemblage with sphalerite was revealed. High contents of strategic metals Cd, Ga, In, Ge in the ZnS matrix, as well as sulvanite (V, Cu) in a single paragenesis were found. A serious reassessment of the potential for industrial use of this mineralization will be required.
-
Date submitted2023-02-10
-
Date accepted2023-09-20
-
Date published2024-04-25
Depth distribution of radiation defects in irradiated diamonds by confocal Raman spectroscopy
Five colored diamonds were investigated. According to the results of the study by FTIR, UV-Vis-NIR and Photoluminescence spectroscopy, they are natural type Ia diamonds. The depth distribution of the color intensity was carried out by measuring the intensity of the PL peak at 741 nm (GR1 center) upon excitation by a laser with a wavelength of 633 nm of Raman Confocal microscope. To minimise the perturbation due to geometrical effects, defect distribution profiles were normalised with respect to diamond Raman peak intensity (691 nm) point by point. For two diamonds, the intensity of the GR1 peak (741 nm) sharply decreased to a depth of 10 µm, and then became equal to the background level, which is typical for irradiation with alpha particles from natural sources like uranium. In other diamonds, the profiles vary slightly with depth, and the color intensity is close to uniform, which is for irradiation with accelerated electrons or neutrons. The source of radiation has not been determined. However, long duration radioactivity measurements of the diamonds suggested that neutrons were not used for colour centers production in the diamonds studied.
-
Date submitted2023-04-29
-
Date accepted2023-10-11
-
Date published2023-10-27
Pink-violet diamonds from the Lomonosov mine: morphology, spectroscopy, nature of colour
The article presents the results of the first comprehensive study of mineralogical and spectroscopic (IR, PL, EPR) characteristics of diamonds from the Lomonosov mine (Arkhangelskaya pipe) with a unique pink, pink-violet colour. It is shown that all crystals belong to the IaA type, with a total nitrogen content in the range of 500-1500 ppm, with a low degree of aggregation. The colour is heterogeneous, concentrated in narrow twin layers. It is presumably caused by the previously described M2 centres. The colour shade is affected by the content of P1 paramagnetic centres (C-defect). A positive correlation is observed between the colour saturation and the intensity of W7 paramagnetic centres. A convergent model of the formation of pink diamonds is assumed, according to which the determining factors are the ratio and concentration of structural impurities in the diamond, its thermal history, and conditions of plastic deformation, and not the origin of the diamond and the petrochemical properties of its host rocks.
-
Date submitted2023-04-02
-
Date accepted2023-06-20
-
Date published2023-07-19
Integration of renewable energy at coal mining enterprises: problems and prospects
This article addresses the issue of developing renewable energy in coal mining enterprises in the Russian Federation. The study presents a methodology for assessing the technical and economic efficiency of introducing renewable energy sources based on simulation modeling. An analysis of the potential of solar and wind energy for coal mining regions in Russia is conducted. The authors use a custom software developed by them to simulate the power supply system for various scenarios of renewable energy integration, including solar generation, wind generation, solar generation with energy storage, wind generation together with solar generation. Based on the example of the Rostov region, a feasibility study of the considered options is presented. Additionally, the research includes a sensitivity analysis of the investment project in the conditions of uncertainty in the development of Russian renewable energy. The research findings indicate that even in market conditions with CO2 emission quotas and prices at the level of the Sakhalin experiment, renewable energy in coal mining enterprises in Russia remains unattractive and requires additional support.
-
Date submitted2022-04-13
-
Date accepted2022-06-15
-
Date published2022-07-26
Thermal history of diamond from Arkhangelskaya and Karpinsky-I kimberlite pipes
This work studies and compares the main morphological, structural, and mineralogical features of 350 diamond crystals from the Karpinsky-I and 300 crystals of the Arkhangelskaya kimberlite pipes. The share of crystals of octahedral habit together with individual crystals of transitional forms with sheaf-like and splintery striation is higher in the Arkhangelskaya pipe and makes 15 %. The share of cuboids and tetrahexahedroids is higher in the Karpinsky-I pipe and stands at 14 %. The share of dodecahedroids in the Arkhangelskaya and Karpinsky-I pipes are 60 % and 50 %, respectively. The indicator role of the nitrogen-vacancy N3 center active in absorption and luminescence is shown. Crystals with the N3 absorption system have predominantly octahedral habit or dissolution forms derived from the octahedra. Their thermal history is the most complex. Absorption bands of the lowest-temperature hydrogen-containing defects (3050, 3144, 3154, 3188, 3310 cm −1 , 1388, 1407, 1432, 1456, 1465, 1503, 1551, 1563 cm −1 ), are typical for crystals without N3 system, where in the absorption spectra nitrogen is in the form of low-temperature A and C defects. The above mentioned bands are registered in the spectra of 16 % and 42 % of crystals from the Arkhangelskaya and Karpinsky-I pipes, respectively. The diamond of the studied deposits is unique in the minimum temperature (duration) of natural annealing. Based on a set of features, three populations of crystals were distinguished, differing in growth conditions, post-growth, and thermal histories. The established regularities prove the multi-stage formation of diamond deposits in the north of the East European Platform and significant differences from the diamonds of the Western Cisurals. The results suggest the possibility of the existence of primary deposits dominated by diamonds from one of the identified populations.
-
Date submitted2021-06-10
-
Date accepted2021-07-27
-
Date published2021-10-21
Defects of diamond crystal structure as an indicator of crystallogenesis
- Authors:
- Evgeny A. Vasilev
Based on the study of a representative collections of diamonds from diamondiferous formations of the Urals and deposits of the Arkhangelsk and Yakutian diamond provinces, we established patterns of zonal and sectoral distribution of crystal structure defects in crystals of different morphological types, identified the specifics of crystals formed at different stages of crystallogenesis and performed a comprehensive analysis of constitutional and population diversity of diamonds in different formations. We identified three stages in the crystallogenesis cycle, which correspond to normal and tangential mechanisms of growth and the stage of changing crystal habit shape. At the stage of changing crystal habit shape, insufficient carbon supersaturation obstructs normal growth mechanism, and the facets develop from existing surfaces. Due to the absent stage of growth layer nucleation, formation of new {111} surfaces occurs much faster compared to tangential growth mechanism. This effect allows to explain the absence of cuboids with highly transformed nitrogen defects at the A-B 1 stage: they have all been refaceted by a regenerative mechanism. Based on the revealed patterns, a model of diamond crystallogenesis was developed, which takes into account the regularities of growth evolution, thermal history and morphological diversity of the crystals. The model implies the possibility of a multiply repetitive crystallization cycle and the existence of an intermediate chamber; it allows to explain the sequence of changes in morphology and defect-impurity composition of crystals, as well as a combination of constitutional and population diversity of diamonds from different geological formations.
-
Date submitted2020-05-08
-
Date accepted2020-06-12
-
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.
-
Date submitted2017-11-06
-
Date accepted2018-01-12
-
Date published2018-04-24
Improvement of the procedure of recruitment of personnel for hazardous work environment
- Authors:
- N. D. Tskhadaya
- D. Yu. Zakharov
With the purpose of the reduction of the number of the emergency and abnormal situations in the oil mines conditioned by the influence of the «human factor» an opportunity of application of the system of permit to the works with respect to the real functional state of the personnel is considered in the paper. A «human factor» may become a reason not only for the occurrence but also for the development of the emergency situation according to the unfavorable scenario.The arduous labor conditions such as heating environment, low level of lighting, high level of the dust load may result in the multiple increase of the negative influence of the factors of the real functional state on the quality and safety of the operations. Reasoning from this fact, the consideration of the factors of the functional state in the process of getting a permit to works in the oil mines is of vital importance and requires a well-reasoned and integrated assessment.
-
Date submitted2015-12-22
-
Date accepted2016-02-13
-
Date published2016-12-23
Risk of injuries among coal mine workers and its hysteresis
- Authors:
- Yu. Parkhanski
The paper gives an overview of employment in coal mining, levels of extraction and injuries among the coal mine operators in Poland over a span of time from 1954 through to 2010. The injury indicators, such as the incidence rate, severity and the generalized loss index, have been assessed for a period of coal mining sector restructuring from 1993 to 2010. Diverging trends have been revealed, resulting in a need to extend the time span of the analysis. Analysis of records from 1954 to 2010 has shown a multiple cyclicity of trends of change in the values used to derive coefficients. The definition of the Injury Risk has been justified, along with a new way for its representation and its interpretation as a new method with account of the previous studies. Based on this method the injuries at the coal mines of Poland during a period of their restructuring have been investigated with analyzed database expansion to include records from 1954 to 2010.As a result a new dependency, namely the injury risk hysteresis, has been identified.
-
Date submitted2009-10-12
-
Date accepted2009-12-29
-
Date published2010-09-22
Types and mechanisms of geodynamic hazard in mineral deposits mining and exploitation of buried and surface engineer constructions
- Authors:
- A. N. Shabarov
It is shown that major emergencies in mineral deposits mining and in exploitation of buried and surface engineer constructions are attributed to active faults. Classification of hazardous zones has been developed. The mechanisms of influence of geodynamic hazard in coal mines and pipeline exploitation were determined. The technology of reduction of geodynamic risk was suggested.
-
Date submitted2009-08-26
-
Date accepted2009-10-27
-
Date published2010-02-01
Scheelites of Gavrilovskoe deposit (first find)
- Authors:
- A. E. Melnik
The Gavrilovskoe deposit (deposit of building stone) is situated in Vyborg district, Leningrad region. There was found scheelite (CaWO 4 ) in the «Northern» quarry at the Gavrilovskoe deposit in 2008. This mineral was identified exactly in the Saint Petersburg State Mining Institute (Technical University) with Raman Spectrometer Renishaw InVia Reflex. It was for the first time that scheelite was found at this place. There was researched a form of one scheelite crystal. The simple forms of this scheelite crystal were detected. It is very interesting to compare simple forms of scheelite from the Gavrilovskoe deposit to different crystals of this mineral, described in any science literature.
-
Date submitted2009-07-17
-
Date accepted2009-09-06
-
Date published2010-04-22
Hydrogeomechanical processes in flooding of mines
- Authors:
- Yu. A. Norvatov
- I. B. Petrova
Hydrodynamic and hydrogeomechanical processes which may occur during flooding of coal mines are considered. Original scheme – model of strain state of waterbearing undermined massif for estimation of uplift of earth surface was suggested.