Khibiny Massif Research Articles

Ikorskyite KMn<sup>3+</sup>(Si<sub>4</sub>O<sub>10</sub>)·3H<sub>2</sub>O — new mineral from the Khibiny alkaline massif (Kola peninsula, Russia)

Ikorskyite KMn3+(Si4O10)·3H2O is new mineral from agpaitic pegmatite of the Kukisvumchorr Mt. (Khibiny Massif, Russia). The mineral forms radial aggregates of light-brown crystals growing on separate quartz crystals or on romanèchite crusts in association with barite, donneite-Y, strontionite, natrolite, vinogradovite, manganoneptunite and organic matter. The mineral is monoclinic, space group P21/c. a = 5.0714(3), b = 8.2731(5), c = 13.3740(11) Å, β = 93.730(5)°, V = 559.93(5) Å3. The eight most intense lines of the diffractogram are: (I-d[Å]-hkl): 55-7.04-011; 41-4.318-110; 100-4.185-11-1; 24-3.956-021; 28-3.339-004; 19-3.095-014; 30-3.014-113; 70-2.939-12-2. The crystal structure of ikorskyite belongs to a new structure type of minerals and inorganic compounds and belongs to the palygorskite group. The mineral is named in honor of Serafim Veniaminovich Ikorsky (1927–2016), a well-known specialist in the field of organic matter and gases research of the Kola alkaline province.

Исследование пространственно-временных закономерностей развития сейсмичности в подработанной толще массива на Расвумчоррском руднике

Studies of the spatial and temporal patterns of seismic activity development in the undermined rock mass have been performed at the Rasvumchorr Mine. The main cluster associated with generation of rock caving in the overhang part has been identified. It is established that caving was developing gradually from the depth of the rock mass towards the surface. The results are presented of estimating the quantitative parameters of the seismic process in the undermined rock stratum, i.e. the energy index and the cumulative apparent volume, which reflect the stress changes in the rock mass. Ranges of the stable state of the rock mass, when the overhang rocks do not cave, as well as the ranges of active fracturing and caving of the overhang rocks have been identified. Changes in these parameters for the studied area of the deposit reflect the loading and strength degradation stages in the rock mass. The results of this study correlate well with the data on actual caving of the undermined rock strata. This work is a continuation of the authors' research into the problem of identifying spatial and temporal patterns in the development of undermined rock strata cavings in the tectonically stressed Khibiny massif.

Impact of Water Saturation of the Medium on the Productivity of Natural-Anthropogenic Seismicity: A Case Study of the Khibiny Massif

The effect of water saturation of the medium on the ability of earthquakes to initiate repeated shocks (productivity) is considered based on the long-term seismological observations and water inflow monitoring data from the Khibiny massif ore deposits. The study indicates that the water saturation of the medium is a factor that has a significant impact on the productivity of earthquakes.

Исследование физико-механических свойств ийолит-уртита в условиях одноосного и трехосного сжатия

The study of deformation and failure processes in rock masses is often carried out in laboratory conditions on samples. Widely used test equipment is used for this purpose, which makes it possible to create loading conditions similar to those inside the rock mass. Basically, the loading mode is implemented when forces are applied only to one side of the sample (along one axis), that is, uniaxial compression or tension. Test equipment that allows creation of loading along three axes, i.e. triaxial compression, is used less frequently. Such equipment is often very expensive, and testing requires a lot of time and resources. Nevertheless, this loading mode is one of the most interesting, since it is close to real conditions in the rock mass. This paper presents the results of experimental studies of ijolite-urtite samples (rocks from the Khibiny massif, the Kola Region) in conditions of uniaxial and triaxial compression. The purpose of the research is to establish how the values of the compressive strength of this rock change, to assess the critical values of the specific strain energy, as well as the tendency to dynamic destruction during the transition from the uniaxial loading mode to the triaxial one. The experimental studies revealed that there exists a sharper increase in the values of compressive strength and the critical values of specific strain energy of the ijolite-urtite samples in conditions of triaxial compression than under uniaxial compression. It has been established that the studied rock is prone to dynamic failure under uniaxial compression and preserve its tendency to this type of failure under triaxial compression.

Influence of Water Saturation of the Medium on the Productivity of Mining-Induced Seismicity: A Case Study of the Khibiny Massif

Influence of Water Saturation of the Medium on the Productivity of Mining-Induced Seismicity: A Case Study of the Khibiny Massif

Atypical components in the composition of nepheline from rocks of the Khibiny massif according to IR spectroscopy data

Nepheline is one of the main rock-forming minerals of the rocks of the Khibiny alkaline massif. Nepheline composition changes depending on the crystallization temperature, which makes it an indicator of rock formation conditions. In addition, nepheline is one of the main concentrators of hydrocarbon gases. The study of nepheline from different rocks of the Khibiny massif by local IR spectroscopy with Fourier transformation (micro-FTIR) has revealed the presence of water and acetylene in its structure. The water content estimated according to the method of statistical quantitative determination of water in nominally anhydrous minerals varies in the range from 0 to 0.78 wt.%. The highest water content has been observed in high-temperature nepheline of early formations (foyaite of the central and outer parts of the massif), and the lowest – in relatively low-temperature nepheline of later rocks of the Main Ring Fault (urtite, apatite-nepheline rock and poikilitic (kalsilite)-nepheline syenite – rischorrite). The study reveals that water enters the structure of nepheline in the form of H2O molecules that occupy vacancies in the potassium sites. The water content in nepheline is controlled by the number of vacancies in its structure. The presence of acetylene has been determined on a qualitative level. Additional studies are required to assess its quantitative content.

Hardware and Software Solutions for the Generation of a Database of HSV-Color Characteristics for the Main Ores and Rocks of the Khibiny Massif

This article presents developed hardware and software solutions based on the application of machine vision technology. The hardware and software solutions were created in order to generate a database of HSV-color value for the main ore types, host rocks, and minerals to define criteria for the in-process identification of the Khibiny apatite in testing the walls of blasting boreholes. The hardware ensures a multi-parametric assessment of the optical characteristics of samples and minerals located on their surface. The designed software solution allows the user to control the measurement process; systematize a description of the textural and structural features of the sample under study; and process images of the core surface. The resultant database of HSV-color value for the main ores and rocks of the Khibiny massif and their constituent minerals will provide an opportunity to search for criteria for the in-process identification of the Khibiny apatite in a mineral mixture.

Influence of Rock Watering on Post-Seismic Activity: A Study on the Khibiny Massif

The article is devoted to the study of the influence of watering of the rock environment on post-seismic activity in the deposits of the Khibiny mountains. Initial data are the results of long-term monitoring of seismicity and observations of water inflows. At a qualitative level, the influence of watering of the environment on the b-value of the Gutenberg – Richter distribution of magnitudes of triggered events, as well as on the parameters of the Omori – Utsu law, which describes the post-seismic activity decay rate over time, was studied.

Spatial distribution of blast-triggered seismic events: a case-study of the Khibiny Massif

Spatial distribution of blast-triggered seismic events: a case-study of the Khibiny Massif

Выявление периодов неустойчивости при формировании обрушений подработанной толщи пород в тектонически напряженном Хибинском массиве

The article focuses on studying the state of the rock mass based on assessment of quantitative parameters of seismic process in the undermined rock strata. Using the apatite-nepheline deposits of the Khibiny massif as an example, it is demonstrated that the dynamics of the energy index and cumulative apparent volume parameters reflects the processes of stress changes in the rock mass, including the time after the blast impact. Boundaries of the study area in the rock mass overhang at the Kukisvumchorr and Yukspor fields were determined to exclude seismicity data corresponding to the areas of active mining operations. Periods were identified that characterize the stable state of the rock mass, when the overhang rocks do not cave, as well as the periods when the process of fracturing and caving of the overhang rocks starts actively. It was found that temporal variations in the apparent volume and energy index can be used to assess the state of the rock mass and the potential fragmentation danger of its parts. The dynamics of these parameters for a certain volume of rocks reflects the phases of loading and strength degradation. The survey results were obtained in the most general form and for large volume sections of the rock mass, despite the fact that they correlate well with the data on actual caving of the undermined rock strata.

METHOD OF PREDICTING SEASONAL VARIATIONS IN WATER INFLOW TO UNDERGROUND MINE WORKINGS USING THE WATER CATCHMENT MODEL WITH CONCENTRATED PARAMETERS

The authors suggest using the water catchment model with concentrated parameters for prediction of seasonal variation in water inflow to mines. The efficiency of the slope runoff model application was previously shown on the base of three test subjects operating apatite-nepheline ore deposits in the Khibiny massif. The article provides a simple methodology for water inflow prediction which doesn’t require any specific software. The example is provided of using this methodology for monthly water inflow prediction based on an underground mine in Kuzbass.

Изменение потока сейсмической энергии при переходе на глубокие горизонты (месторождение Апатитовый Цирк, Хибинский массив)

The study is aimed at assessing the changes in seismic energy flow as mining operations advance to deep levels as exemplified by the Apatite Circus apatite-nepheline deposit (Khibiny Massif), which underground reserves are difficult to develop due to the presence of the nearby Rasvumchorr Plateau deposit, which is mined using the open-pit method. Underground mine workings and open-pit walls are located in the bordering area. A large number of fractures and tectonic faults are exposed in this area, which become waterlogged when the snow thaws. As a result, the stress-and-strain state of certain rock mass sections (mainly the tectonic fault zones) changes, which generally affects the seismic settings of the deposits. Along with transition of the mining operations to greater depth, an increase is observed in the number of seismic events and their energy in the lower levels of the mine. Also the fracturing processes in the overhand part of the rock mass are reflected in seismicity activation. The paper presents maps showing the spatial distribution of the seismic energy flows of various events across the mine field as mining progresses to greater depth. It has been established that there exist areas of increased level of seismic energy flow distribution, corresponding to the compressive strain zones (two lower levels, where intensive mining is in progress) and tensile strain zones in the overhand part of the rock mass ( the top third layer), where a gradual collapse of the near-surface area of the mass occurs.

Rockburst hazard potential assessment of rocks of the Khibiny massif deposits according to the Kaiser criterion

The mining and geological conditions in the mines worsen due to changes in the stress-strain state of rock masses and their structural disturbance when mining goes to great depths. Under such conditions, it is necessary to assess the impact hazard of ores and rocks that make up the mined deposits. For the prompt implementation of such an assessment, it is proposed to use the Kaiser criterion consisting in the analysis of experimental data obtained on rock samples. The paper presents the results of laboratory testing of rock samples from the deposits of the Khibiny massif under uniaxial compression and tension. The values of their brittleness coefficients have been determined. The possibility of using the Kaiser criterion for a preliminary assessment of rock burst hazard potential has been shown. It has been established that spotty-trachytoid melteigite and trachytoid ijolite-melteigite have a high potential for impact hazard, while spotted apatite-nepheline ore does not have such a potential. A comparison has been made of the obtained results of rockburst hazard assessment of hard rocks from the Khibiny massif deposits according to the Kaiser criterion, as well as the criterion of the Mining Institute of the KSC RAS and the criterion of A. N. Stavrogin. It can be noted that the Kaiser criterion makes it quite easy to carry out a preliminary assessment of rock burst hazard based on the results of testing samples on standard presses. However, to increase the degree of reliability of the data obtained, they must be certified according to the criterion of the Mining Institute of the KSC RAS or the criterion of A. N. Stavrogin.

The Influence of Mining Operations on Seismic Activity of the Rocks in Underground Mines of the Khibiny Massif

The Influence of Mining Operations on Seismic Activity of the Rocks in Underground Mines of the Khibiny Massif

The Influence of Mining Operations on Seismic Activity of the Rocks in Underground Mines of the Khibiny Massif

The issues of the causes and factors of manifestation of seismic activity during the extraction of minerals in the deposits of the Khibiny massif, which are mined underground, are considered. Based on seismic monitoring data, groups of seismic activity were identified, such as seismicity in the working area, directly related to blasting and natural seismicity, related to other mining and geological factors. The difference in the characteristics of the manifestation of seismicity for these two groups of seismic events is shown.

Geological and mineralogical characteristics of corundum-bearing rocks in the Khitostrov occurrence (Northern Karelia)

The geological and mineralogical features of the formation of Paleoproterozoic corundum-bearing rocks of the Khitostrov deposit are considered. The formation history of the corundum-bearing rocks is divided into periods and the characteristics of the Karelian-Kola sapphire-rubiferous province are highlighted. The specific features of the genesis of corundum-bearing complexes in the volcanic part of the Fennoscandinavian Shield are marked. Corundum formation in xenoliths of the alkaline complex of the Khibiny massif is typical of the Kola Peninsula. In Karelia, corundum-bearing rocks are formed within the boundaries of the Belomorian Mobile Belt and two types are distinguished – corundum-bearing rocks in aluminous plagiogneisses (first type) and corundum-bearing rocks in metabasites (second type). All corundums of the Belomorian Mobile Belt were formed due to metasomatic processes during the Svecofennian period of activation. Based on the geology and mineralogical and technological features of a known occurrence, the Khitostrov corundum occurrence is comprehensively evaluated as the main representative of the Karelian-Kola sapphire-rubiferous province. The methods for corundum-bearing rock stripping are considered and the efficiency of optical separation of Khitostrov’s corundum ores is assessed. The results of this study supplement the database on this unique geological object and provide a background for the assessment of the corundum area of the Belomorian Mobile Belt.

Mckelveyite group minerals – Part 2: Alicewilsonite-(YCe), Na2Sr2YCe(CO3)6 ⋅ 3H2O, a new species

Abstract. The new mckelveyite group mineral alicewilsonite-(YCe), ideally Na2Sr2YCe(CO3)6 ⋅ 3H2O, was found at Mont Saint-Hilaire, Quebec, Canada, and subsequently at the Saint-Amable sill, Quebec, Canada, and the Khibiny Massif, Kola Peninsula, Russia. Alicewilsonite-(YCe) crystals are commonly hemimorphic pseudotrigonal and pseudohexagonal and show barrel-shaped, saucer-shaped, spindle-shaped, cone-shaped, columnar, tabular, and platy habits. They are usually up to 2–3 mm in size with some larger crystals reaching 2–3 cm. The crystals often form stacked or parallel growth aggregates and rosettes. Alicewilsonite-(YCe) colour varies from pale yellow to yellow, lemon yellow, green yellow, orange-yellow, pale green to green, pale grey to grey, green grey, beige, and colourless. The streak is white; the lustre is vitreous. The cleavage is fair to indistinct, parallel to (001). The Mohs hardness is 3. Dcalc is 3.37 g cm−3. Alicewilsonite-(YCe) is optically biaxial (+), with α=1.554(3), β=1.558(3), γ=1.644(2), 2V (calc.) = 26∘, 2V (meas.) = 20(3)∘ (589 nm). The IR spectrum is reported. The composition (wt %, average of six analyses) is Na2O 7.42, CaO 0.72, SrO 21.49, BaO 1.41, Y2O3 8.52, La2O3 5.93, Ce2O3 9.52, Pr2O3 0.59, Nd2O3 1.75, Sm2O3 0.46, Gd2O3 0.83, Dy2O3 1.65, Ho2O3 0.34, Er2O3 1.21, Yb2O3 0.64, CO2 29.33, H2O 6.13, total 97.94. The empirical formula of the holotype calculated on the basis of six cations is Na2.11Ca0.11Sr1.83Ba0.08Y0.67(Ce0.51La0.32Pr0.03Nd0.09Sm0.02Gd0.04 Dy0.08Ho0.02Er0.06Yb0.03)Σ1.20(CO3)5.88 (H2O)3.00. The mineral is triclinic, P1, a=9.0036(6) Å, b=9.0175(6) Å, c=6.7712(5) Å, α=102.724(2)∘, β=116.398(2)∘, γ=60.003(2)∘, V=426.46(5) Å3, and Z=1. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 6.07(31)(001), 4.372(100)(120, 2‾1‾1, 11‾0), 4.037(25)(1‾11, 1‾2‾1, 210), 3.201(25)(121, 2‾1‾2, 11‾1), 2.831(67)(1‾12, 1‾2‾2, 211, 1‾21, 21‾0), 2.601(39)(030, 3‾3‾1,3‾01), 2.236(24)(2‾4‾1, 2‾21, 4‾2‾1). 2.019(23)(003, 2‾22, 2‾4‾2‾, 420). 1.9742(24)(032, 3‾03, 3‾3‾3, 331, 03‾2, 301). The crystal structure, solved and refined from single-crystal X-ray diffraction data (R1=0.055), is of the weloganite type.

Seismicity variations in space and time in the area of the Saamy fault, Khibiny Massif, Kola Peninsula

The paper analyzes the dynamics of seismicity in the vicinity of the Saamy fault, Khibiny Massif, Kola Peninsula. The qualitative recording of seismic events has been carried out there since 2008. The study area is characterized as rockburst-hazardous and complicated by a geological fault, is developed by open pit mining, and includes the Kukisvumchorr and Yukspor deposits. In order to identify the influencing factors and mechanisms of rock mass failure, the authors used the spatial–temporal clustering of data, and analyzed the location and possible causes of the clusters. The areas with long-term seismic activity near the fault and the areas with short-term increase in seismic activity which is often induced by triggering factors are detected. The clusters in the console part of the rock mass are identified. At the Yukspor deposit, rock mass failed and caved into the Saamy open pit. It is found that opencast mining with blasting in the fault zone is a trigger for the fault activation, which is confirmed by seismic events recorded not only at the working level but also higher. The seasonal increase in water inflows is an additional factor in the fault activation; some clusters are characterized by a higher level of seismic activity during such periods. According to the authors’ conclusion, the analysis of seismicity on the basis of spatial and temporal data clustering allows timely revealing of seismic activation causes and enables necessary preventive measures (rock mass destressing, sectional breaking, bulk blasting to reduce stress level, etc.), which in general reduce the risks of man-induced catastrophes.

Kinematics of minor disjunctive structures and tectonic stresses in the southern part of the Khibiny massif

Kinematics of minor disjunctive structures and tectonic stresses in the southern part of the Khibiny massif

The Molecular Weight Distribution of Occluded Hydrocarbon Gases in the Khibiny Nepheline–Syenite Massif (Kola Peninsula, NW Russia) in Relation to the Problem of Their Origin

The origin of hydrogen–hydrocarbon gases present in the rocks of the Khibiny massif in unusually high concentrations has been the subject of many years of discussion. To assess the role of potential mechanisms and relative time of formation of gases occluded in inclusions in minerals, the molecular weight distribution of C1–C5 alkanes in the main rock types of the Khibiny massif was studied. For this purpose, the occluded gases were extracted from rocks by mechanical grinding and their composition was analyzed on a gas chromatograph. It is established that the molecular weight distribution of occluded hydrocarbon gases in the Khibiny massif corresponds to the classical Anderson–Schulz–Flory distribution. In addition, the slopes of the linear relationships are relatively steep. This indicates a predominantly abiogenic origin of the occluded gases of the Khibiny massif. At the same time, a small proportion of biogenic hydrocarbons is present and is associated with the influence of meteoric waters. It was also found that in the Khibiny massif, the proportion of relatively high-temperature gases decreases towards the Main foidolite Ring in the following sequence: foyaite and khibinite–trachytoid khibinite–rischorrite and lyavochorrite–foidolites and apatite–nepheline ores. In the same sequence, an increase in the proportion of heavy hydrocarbons and the increasing role of oxidation and condensation reactions in the transformation of hydrocarbons occurs.