Ore Samples Research Articles

Experimental and rheological modelling on the stabilization of iron ore slurry using a biosurfactant extracted from Aloe barbadensis Miller

The pipeline transportation of iron ore slurry (IOS) is an eco-friendly alternate mode to transport the raw materials to longer distance and reduce the transportation network congestion problems. Proper selection of surfactant could modify mineral’s viscosity, dispersion and wetting characteristics effectively as may be desired, which may further be monitored. A surfactant alters surface characteristics after being adsorbed onto minerals by altering the interfacial behaviour. This work is first report of the influence of a biosurfactant sourced from Aloe barbadensis Miller on the rheological behaviour of a high-grade iron ore (IO) sample at 45–72% by mass slurry concentrations range. The observed rheological parameters confirmed the non-Newtonian flow behaviour of the slurry. The collected IO and dried IOS samples were subjected to UV-Vis, XRF, PSD, XRD, SEM and EDS analyses. Experimental rheological data at varying concentrations was tested on various models to ascertain the best-fit rheological model for IOS transport. The Bingham model was found to be the most suitable to model the rheology of IOS. Experimental rheological behaviour of IOS was found to be linear with the yield stress. The study shall help to ascertain the suitability of a biosurfactant to stabilise high grade iron ores for pipeline transportation.
 KEY WORDS: Iron ore slurry, Aloe barbadensis, Rheological measurements, Rheological modelling
 Bull. Chem. Soc. Ethiop. 2024, 38(3), 615-629. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i3.6

Principal component analysis of mineral and element composition of ores from the Bayan Obo Nb-Fe-REE deposit: Implication for mineralization process and ore classification

The Bayan Obo Nb-Fe-REE polymetallic deposit in northern China is the world’s largest light REE deposit. The deposit was formed through multiperiodic alteration and mineralization, and thus mineral species and assemblages are extremely complex. To date, there is still no consensus on the classification of ore types, and research on the paragenetic association of minerals is still inadequate. Eighty ore samples are divided into seven types according to altered minerals, including dolomite, iron oxide, aegirine, riebeckite, biotite, fluorite, and barite types. These samples were analyzed by a TESCAN Integrated Mineral Analyzer (TIMA) for their mineral and element composition. The data set was investigated by principal component analysis (PCA) to reveal the mineralization and alteration information and classify the ores.PCM1 to PCM3 and PCE1 to PCE3 represent the first three principal components for PCA results of minerals and elements, respectively. The results indicate that PCM1 may distinguish rare earth mineralization from barite and silicification alteration that is associated with the latest fluids. PCM2 can distinguish mineralization and alteration associated with Nb from those associated with REE. The combination of PCM2 and PCE1 indicates that the precipitation of REE may be closely related to fluorination and phosphate, while the combination of PCM2 and PCE3 indicates that the Nb mineralization may be more closely related to alteration of riebeckite and biotite, as well as to Ti-rich fluids. In addition, PCM3 distinguishes the Th mineralization and associated fluorination from other alteration and mineralization. Based on PCA results, the above seven ore types can be classified into three types: dolomite REE ore, Fe-REE-F ore, and Nb-rich ore, which provides a simplified and comprehensive classification for Bayan Obo ores. PCA-based approach combining geochemical and mineralogical data can quickly identify ore types, which is helpful in mineral exploration.

Monazite and zircon U[sbnd]Pb and muscovite 40Ar/39Ar geochronology constraints on the timing of magmatism and mineralization in the Huxingshan tungsten deposit, South China

The Huxingshan W deposit (0.21 Mt. WO3 @ 0.3 %) in northeastern Hunan province is located at the western margin of the Jiangnan tungsten belt (JNB), South China. It consists of a series of magma-derived scheelite-quartz-muscovite (SQM) veins in the F1 fault (which contains over 60 % of the W resource), beneath Niutitang Formation (Fm.) carbonate rocks, and above Yijiaqiao Fm. slate (sub-economic), distal from the concealed two-mica granite, which is thought to be responsible for the tungsten mineralization. In this study, we employ LA-ICP-MS zircon and monazite UPb, and muscovite 40Ar/39Ar dating to constrain the timing of magmatism and W mineralization at the Huxingshan deposit. Monazite and zircon dating yield coeval ages of 137.6 ± 0.5 Ma and 138.0 ± 0.5 Ma, respectively. Our muscovite 40Ar/39Ar dating yielded well plateau ages of 132.9 ± 0.6 Ma, 132.2 ± 0.6 Ma, 130.7 ± 0.5 Ma, and 129.7 ± 0.6 Ma for four representative SQM vein ore samples occurring in the Niutitang Fm. carbonate, F1 fault, and Yijiaqiao Fm. slate, indicating multiple pulses of ore-forming fluid infiltration at Huxingshan. Our age data demonstrate that the two-mica granite emplaced at ∼137.6 Ma, significantly earlier than the pulsed W mineralization at ca. 132.9–129.7 Ma. The lack of spatial and temporal association precludes any genetic link between them. Thus, we infer that the ore-forming fluids likely originated from undiscovered deep plutons and ascended through the F1 fault. Besides, our reliable ages coincide with the two periods of large-scale Mesozoic magmatism and W mineralization phases in the JNB, with the 137.6 Ma magmatism falling within the first phase (150–135 Ma), while the W mineralization (ca.132.9–129.7 Ma) falls within the second phase (130–125 Ma). Of which, the second phase, including the Huxingshan, Xianglushang, Dongping, and Jianfengpo deposits, are situated in the western JNB and show further potential in this region.

Study of the material composition of refractory gold-bearing ore from the Aktobe deposit

The study of the material composition of gold-bearing ores includes the determination of quantitative chemical and mineral composition, forms of noble metals, granulometric composition, and physical and mechanical properties to choose the direction for the development of an effective technology of their complex enrichment. This work is devoted to the study of the material composition of refractory gold-bearing ore of Aktobe deposit. It was determined that the content of gold is 1.55-1.6 g/t, the mass fraction of silver is 42-43 g/t, and the content of sulphur is low and is 1-1.1% respectively. Of non-ferrous metals, zinc 0.17%, and lead 0.15% are present in insignificant amounts, and the content of harmful impurities antimony and arsenic are insignificant and amounted to 0.01 and 0.05%. The ore sample has a relatively uncomplicated mineral composition: rock-forming minerals represented by quartz, potassium feldspar, calcite, and mica predominate significantly. Ore minerals are represented by pyrite up to 10 %, limonite up to 0.5 %, galena 0.15-0.2 %, sphalerite 0.17-0.2 % and gold. Physical and mechanical properties of the ore were determined. According to the category of crushability, the ore belongs to the category of medium hardness. According to Bond's method, the "index of network Wi" of ball milling was determined for the initial ore, which was 19.3 kW∙h/t∙μm0.5. Based on the obtained data on the study of material composition, further research will be directed to the study of gravity and flotation enrichment.

Research on the possibility of obtaining medium-carbon ferromanganese from the Djezdinskoe deposit

In this article, the results of laboratory studies on the smelting of medium-carbon ferromanganese using Djezdinskoe ores are presented. Kazakhstan has significant reserves of manganese ores represented by iron-manganese and carbonate-oxide ores. The manganese ores of the Djezdinskoe deposit are characterized by a relatively high manganese content (48%) and low iron content (2-5%). Sieve analysis was used to study the particle size distribution of the ore. Based on the results of the sieve analysis of ore samples obtained after sieving, a high manganese content (53.54%), low iron content (0.47%), and silicon dioxide content (2.25%) were identified. Laboratory experiments were conducted on smelting medium-carbon ferromanganese in the high-temperature Tamman furnace. According to the results of the laboratory experiments, it is recommended to use the size classes of -5.0 + 0.0 mm to obtain high-quality low-phosphorus silicon-manganese alloy and the size class of +5.0 to produce medium-carbon ferromanganese. The average chemical composition of the metal and slag is as follows: % Mn – 86 – 88; Si – 0.04 – 0.35; Fe – 1.78 – 2.0; P – 0.06 – 0.09; C – 1.5 – 2.0; MnO – 19-20; SiO2 – 13.94-14.5; CaO – 23.35 – 24.85; MgO – 13.25-14.0. Thus, an optimal technological scheme has been developed for the production of a wide range of manganese ferroalloys.

Prevention of Silica Gel Formation for Eudialyte Study Using New Digestion Reactor

This work includes a combined hydrometallurgical treatment of a eudialyte ore sample with a subsequent preparation of leaching residue using mechanical separation methods. Hydrometallurgical treatment contains dry digestion with sulphuric acid at room temperature and filtration of the obtained product. The objectives of adopting these procedures are to test a new digestion reactor in order to prevent silica gel formation from the eudialyte ore. The obtained results revealed that silica gel formation is prevented during dissolution with sulphuric acid. A high leaching efficiency of light rare earth elements (La, Ce, Nd, Y) was reached using the dry digestion process with sulphuric acid, where the starting molarity was 12 mol/L. After the filtration process, magnetic separation is studied as the main method to recover weakly magnetic minerals like amphiboles and pyroxenes from the leaching residue in the magnetic fraction and feldspars in the nonmagnetic fraction. A new combined research strategy was developed for the production of different concentrates such as the one bearing Zr, Hf, and Nb.

Studying Flotation of Gold Microdispersions with Carrier Minerals and Pulp Aeration with a Steam–Air Mixture

This work is aimed at obtaining new knowledge in the field of interactions of polydisperse hydrophobic surfaces in order to increase the extraction of mineral microdispersions via flotation. The effect of high velocity and the probability of aggregating fine particles with large ones are used to increase the extraction of finely dispersed gold in this work. Large particles act as carrier minerals, which are intentionally introduced into a pulp. The novelty of this work lies in the fact that a rougher concentrate is used as the carrier mineral. For this purpose, it is isolated from three parallel pulp streams by mixing the rougher concentrate, isolated from the first stream of raw materials, with an initial feed of the second stream; accordingly, the rougher concentrate of the second stream is mixed with the initial feed of the third stream, and the finished rougher concentrate is obtained. In this mode of extracting the rougher concentrate, the content of the extracted metal increases from stream to stream, which contributes to the growth in its content in the end product. Moreover, in order to supplement forces involved in the separation of minerals with surface forces of structural origin in the third flotation stream, the pulp is aerated for a short time (about 15%–25% of the total) with air bubbles filled with a heat carrier, i.e., hot water vapor. Within this accepted flotation method, the influence that the surface currents occurring in the wetting film have on its thinning and breakthrough kinetics is proposed to be in the form of a correction to a length of a liquid slip in the hydrophobic gap. The value of the correction is expressed as a fraction of the limiting thickness of the wetting film, determined by the condition of its thickness invariability when the streams are equal in an interphase gap: outflowing (due to an action of the downforce) and inflowing (Marangoni flows and a thermo-osmotic stream). Gold flotation experiments are performed on samples of gold-bearing ore obtained from two deposits with conditions that simulate a continuous process. Technological advantages of this developed scheme and a flotation mode of gold microdispersions are shown in comparison with the basic technology. The purpose of this work is to conduct comparative tests on the basic and developed technologies using samples of gold-bearing ore obtained from the Natalka and Olimpiada deposits. Through the use of the developed technology, an increase in gold extraction of 7.99% and in concentrate quality (from 5.09 to 100.3 g/t) is achieved when the yield of the concentrate decreases from 1.86 to 1.30%, which reduces the costs associated with its expensive metallurgical processing.

On the mineralogy of the Ukonik gold deposit in Transbaikalia (Russia)

As a result of studying new ore samples from the Ukonik deposit, new data on the composition of pyrite was obtained, the composition of electrum was studied for the first time and plattnerite, hessite, jalpaite, silver-bearing covellite and greigite were identified, and the sequence of their formation was determined. It was determined that a significant part of the pyrite (48%) contains arsenic in the amount of 0.82 - 2.28 wt.%, which is typical for the upper parts of many gold deposits. This is also evidenced by an insignificant admixture of cobalt (0.5 – 0.55 wt.%) in only two samples. The bulk of gold in the ore is associated with electrum, containing from 41.26 to 63.11 wt.% gold. Mercury electrum was found to contain up to 3.29 wt.% Hg. For the first time in Transbaikalia, plattnerite, which usually belongs to the minerals of the supergenesis zone, has been identified and studied in the ores of the upper part of the Ukonik deposit. In this case, it is one of the last products of the evolution of the hydrothermal mineral-forming system, preceding the formation of dolomite. Hessite containing variable amounts of copper, lead and antimony was discovered for the first time. This hessite-like telluride is of interest for further research.

Исследование реагентного режима флотации одного из золоторудных месторождений Восточного Забайкалья

The relevance of the problem is that the final product of flotation of the Eastern Transbaikalia deposit to be sold, has a low content. The object of the research is as follows: technological sample of the original ore of the gold deposit in Eastern Transbaikalia. The purpose of the research includes the search for the optimal reagent regime during the flotation process to improve technological performance. The research objectives are to study the chemical and mineral composition and to investigate the possibility of using reagents based on alcohols and C4-C8 esters “KETGOL”, “KETGOL improved”, “KON-92”. The research methodology is based on studying the properties of the components and their influence on the flotation process. The material composition of the ores has been studied by methods of atomic emission spectral quantitative analysis, X-ray fluorescence, phase atomic absorption analyzes and atomic emission analysis with inductively coupled plasma ICP-AES. The mass fraction of total and organic carbon is determined by the infrared absorption method. The gold content in the original ore is based on assay data. When conducting flotation experiments, the equipment of JSC Irgiredmet has been used. As a result of the research, the material composition is studied and laboratory studies of flotation enrichment of the ore sample are carried out. Conclusions on the material composition are as follows: the studied ore sample belongs to the primary gold-quartz, moderate sulfide mineral type of ore. The gold content is 3.12 g/t, silver – 6.9 g/t. The gold in the ore is mostly small and thin, its fineness is 708. The results of flotation enrichment have showed that the use of the KETGOL reagent as an additional collector to potassium butyl xanthate (BX) in a 2:1 ratio with a total consumption of 90 g/t is an effective means of increasing gold recovery to ~87–89 %, with In this case, the quality of the main flotation concentrate remains at the level of ~15.5–16.5 g/t.

High-frequency sampling of point samples of lump ores

High-frequency sampling of point samples of lump ores

Speciation of the binary Cr(III)-citrate system in the leachate samples of phosphate ore

This report focuses on the determination of chromium chemical forms in the lixiviates of phosphate ore using speciation modelling with the MATLAB 7.7 Language. Citric acid has been used as aleaching agent for the extraction of chromium (III) from phosphate ore. A computational approach was used to determine the concentration of differentionic species present in the Cr(III)-citric acid system. The results show that the main aqueous species identified in the systemwere both free and complex ions. In addition, it was found that the concentration of total chromium in the leachate was dependent on the concentration of citric acid.On the other hand, the formation of different species and the evolution of their concentration led to an increase in the ionic strength of the solution. The ionic complex CrHCit+ showed the highest activity coefficientamong the different Cr (III) species. It was also observed that free ionic species (H3O+, H2Cit-, Cr3+) have a higher activity than chromium ionic complexes (CrH3Cit3+, CrH2Cit2+, CrHCit+).

Acid and ammonia leaching of secondary copper sulfides

The study focuses on understanding the efficiency and kinetics of copper recovery from secondary sulphide ores, which are increasingly becoming a significant source of copper. An experimental investigation was undertaken to assess the leaching behaviour of secondary copper sulphides in acid and ammonia media. The test work consisted of ore sample characterisation, including physico-mechanical properties determination, chemical assay, whole rock analysis, mineralogy, and copper distributions, followed by acid consumption tests, agglomeration, and agitation leach tests. Leaching tests were conducted in a lab-scale agitated reactor using 100 g of the ore sample, 0.3 l of leach solution, а stirring rate of 420 rpm and a leach time of up to 200 hours. The effect of the reaction time and oxidant (Fe3+, NO+) concentration on the copper recovery was evaluated. The maximum copper extraction was obtained in the test performed using acid media with the addition of NO+ as an oxidant. Further, a potential hydrometallurgical process option for recovering copper from secondary sulphide sources is proposed.

Capabilities and limitations of Pb, Sr and Fe isotopic analysis of iron-rich slags: a case study on the medieval port at Hoeke (Belgium).

In this work, an analytical approach was developed for Pb, Sr, and Fe isotopic analysis of archaeological samples recovered from an iron work site by using multi-collector inductively coupled plasma - mass spectrometry (MC-ICP-MS). The sample types include slag, coal, clay and hammer scales, all obtained from an archaeological site at Hoeke (Belgium). Despite the wide concentration range of the target elements present in the samples and some sample manipulations necessarily performed outside of a clean laboratory facility, the analytical procedure yielded accurate and precise results for QA/QC standards while blank levels were negligible. Preliminary results concerning Pb, Sr and Fe isotope ratio variations in archaeological materials associated with iron working processes are provided. The samples revealed high variability in metal isotopic compositions, with the 208Pb/207Pb ratio ranging from 2.4261 to 2.4824, the 87Sr/86Sr ratio from 0.7100 to 0.7220, and δ 56Fe values from -0.34 to +0.08‰, which was tentatively attributed to the mixing of materials during the iron production process or variability within the source material. Also, contamination introduced by coal and furnace/hearth lining material could have contributed to the wide range of isotopic compositions observed. Because of the absence of information and data for primary ore samples to compare with, the provenance of the materials could not be established. The present study highlights the challenges in interpreting archaeological data, particularly in terms of the isotopic variability observed. It underscores the necessity of integrating analysis data with historical and archaeological knowledge. Further research, involving detailed analysis of these source materials combined with robust historical evidence, is essential to validate hypotheses concerning the origin of iron.

Effect of Direct and Indirect Pre-Oxidation of Gold Ore from Doup North Sulawesi using Ozone Gas on the Gold Extraction in the Cyanidation Process

Refractory gold ore is a type of gold ore that is difficult to process when treated through a conventional cyanidation process. Pre-oxidation using ozone gas is one of the pre-treatment methods that can be used to improve gold recovery from sulfide-type refractory ore. This study used gold ore samples from Doup, North Sulawesi, Indonesia, to study the effect of direct and indirect pre-oxidation using ozone gas on gold recovery and subsequently treated by a cyanidation process. Direct and indirect pre-oxidation experiments were carried out at different pHs and using two raw materials for ozone generation (air and O2). The slurry obtained from the pre-oxidation experiments was filtered, and the filtrate was analyzed for the concentration of dissolved Cu, Fe, and Zn using atomic absorption spectroscopy (AAS); meanwhile, the residue from each pre-oxidation experiment was leached by cyanidation to obtain a pregnant leaching solution (PLS), which was analyzed for its gold concentration using AAS. The percentages of dissolved Cu, Fe, and Zn during pre-oxidation increased with the pre-oxidation time when the acidity was maintained at pH 2, using pure O2 as the ozone raw material. The direct pre-oxidation process at pH 2 using air as the ozone raw material increased gold extraction from 79.08% to 82.78% in the cyanidation process. The pre-oxidation experiments performed without controlling the pH resulted in lower gold dissolutions than the pre-oxidation conditions at pH 2. Possible causes of the lower gold dissolution were discussed.

Mitigating the influence of topographies on hyperspectral images for the sorting of iron ore based on variational mode decomposition and spectral property

Hyperspectral imaging (HSI) can be applied for the purpose of sorting iron ores with varying total iron (TFe) content. However, the surface topographies of iron ore can negatively impact its hyperspectral images, consequently affecting the sorting effectiveness for each individual piece of iron ore. To address this issue, this study conducted an experiment on hyperspectral image of the iron ores. Firstly, variational mode decomposition (VMD) was employed to decompose the spectra of iron ore into trend signals and peak-valley signals. The two signals were then used for the calculation of three spectral properties (baseline-shift level, steepness level, and amplitude level). To identify the critical property capable of distinguishing normal spectra and the topographies-affected, the difference of the three spectral properties between the topographies-affected and the normal spectra were analyzed. According to the analysis results, a VMD-based correction model (VMDC) was proposed, which aims to identify the topographies-affected spectra in an ore and then correct them to resemble the normal spectra. Finally, the coefficient of variation (CV) for the correction was assessed and a test was conducted for TFe content prediction and sorting of each piece of iron ore. There are three primary conclusions summarized as follows:1. The mean Jeffries–Matusita distance (JMD) of baseline-shift level, steepness level, and amplitude level between normal spectra and topographies-affected spectra were 1.889, 1.307, and 1.170, respectively. This implies that baseline-shift level can be regarded as a key property for distinguishing whether a spectrum is topographies-affected or not. 2. After correction, there was a noticeable improvement in the topographies-affected areas of the ore samples, and the topographies-affected spectra showed the consistence with the normal spectra. Upon examination, the mean CV for VMDC is 0.115, whereas the uncorrected data has a mean CV of 0.315, indicating a reduction in spectral variability after VMDC correction. The results demonstrate the effectiveness of VMDC in mitigating the impact of topographies. 3. In the TFe content prediction and sorting, VMDC consistently demonstrates the best performance, for example when using RF as the regressor, coefficient of determination (R2) and accuracy of Original Data-RF, MSC-RF and VMDC-RF were 84.3% and 0.894, 86.7% and 0.903, and 88.7% and 0.921. The evaluation results confirm that VMDC can improve iron ore sorting. Overall, the proposed method shows potential for practical applications in iron ore sorting.

Rapid Determination Of Uranium In Ore Samples By Online Extraction Coupled ICP-MS

Rapid Determination Of Uranium In Ore Samples By Online Extraction Coupled ICP-MS

Use of backscattering ultrasound parameters for iron ore varieties recognition

Purpose. Development of the method for recognizing the main mineral-technological varieties of iron ore in the deposits being developed by selecting an analytical model for the spectral characteristics of the received ultrasonic echo signals and quantitative assessment of their parameters. Methodology. The work uses methods for modeling the processes of propagation of ultrasonic waves in a randomly heterogeneous medium. The process of backscattering of ultrasound in mineral structures formed by inclusions of iron ore of various varieties and associated rock was considered. The estimated parameters of the spectral characteristics of the inversely scattered probing ultrasound pulse were studied. Findings. A method for recognizing the main mineral and technological varieties of iron ore of the deposit being developed, based on the parameters of the propagation of ultrasonic waves in the studied samples, was proposed. This is achieved by selecting an analytical model for the spectral characteristics of the received echo signals and quantifying their parameters. The amplitude of the echo signal and its spectral properties depends on the size and concentration of the scatterers, i.e., the structural and textural features of the iron ore sample under study. Taking into account these factors, the extracted parameters of the model were used to identify the main mineralogical and technological varieties of iron ore of the studied deposit. Originality. The proposed method for recognizing mineral-technological varieties of iron ore differs from the known ones in that the amplitude, central frequency, and bandwidth of the amplitude spectrum of the Gaussian parametric model of the measured echo signals are used as evaluation parameters. Practical value. The proposed scientific and technical solution allows for operational non-destructive control of the main mineralogical and technological types of iron ore in the process of its extraction and processing.

Solving the mystery of natural pyrite flotation – A mineralogy-based approach

Many different types of pyrite have been observed in the mineral processing industry, varying in texture, chemical composition, electrochemical properties, and flotation response. One particular type of pyrite has been noted for its unusual behaviour is framboidal or “carbonaceous” pyrite. Specifically, a long history of carbonaceous pyrite presence has been recorded and studied at Glencore's Mount Isa Mines.This work is a detailed examination of the mineralogical characteristics of ore samples containing different pyrite types, to determine the underlying drivers of natural pyrite flotation. The work also revisits the original hypothesis that pyrite floatability is facilitated by the presence of carbonaceous material within the mineral matrix.Overall, this work closely mirrored that of previous studies, with the results closely aligned. The main difference is that when multiple ore domains are subjected to the same analysis, the flotation behaviour of carbonaceous content and pyrite appear to be independent. Instead, excessive natural flotation recoveries of pyrite are likely to be driven by factors that include the effect of galvanic interactions between chalcopyrite and pyrite.

Geological and Geochemical Characteristics and Genesis of the Laoyingqing Zinc Deposit in Northeastern Yunnan

The Laoyingqing zinc deposit is located in the Pb-Zn deposit concentration district in northeastern Yunnan, with a geotectonic location on the southwestern edge of the Yangtze block. This deposit occurs in the interlayer fracture zone of the Huangcaoling Formation slate in the Middle Proterozoic Kunyang Group. In this deposit, zinc is significantly enriched compared to lead, and the sulfur isotopic composition of sphalerite shows δ34SCDT close to negative values. These characteristics are different from the common Pb-Zn deposits that occur in Sinian and Carboniferous carbonate rocks in northeastern Yunnan. The genesis of this deposit and its similarities to and differences from other Pb-Zn deposits hosted in carbonate rocks in the Sichuan–Yunnan–Guizhou Pb-Zn metallogenic triangle area (SYGT) need further research. This article selects typical rock (ore) samples for fluid inclusion, trace element, and H–O isotope analyses. The results show that (1) the homogenization temperature of the fluid inclusions is 130~306.5 °C, the salinity is 7.17 wt%~20.67 wt% NaCleq, and the density of the ore-forming fluids is 0.86–1.07 g/cm3. Overall, these ore-forming fluids belong to medium–low-temperature, medium–low-salinity, and medium–low-density ore-forming fluids, and they have reducibility. The fluid pressure is 36.3~85.6 Mpa, and the mineralization depth is 1.34~3.17 km. (2) The ore-forming fluids mainly came from deep-source metamorphic water and basin brine containing organic matter. (3) The ore-forming materials mainly came from the surrounding rocks (Kunyang Group). (4) The trace element characteristics of this deposit are different from sedimentary-exhalative type, magmatic hydrothermal type, and skarn type of Pb-Zn deposits, and have little difference from MVT Pb-Zn deposits. Based on the comprehensive analysis, this deposit is classified as a medium–low-temperature hydrothermal vein-type zinc deposit unrelated to magmatic activity. This study extends the ore-bearing surrounding rocks of Pb-Zn deposits in the SYGT to the slate of the Kunyang Group, enriching the regional Pb-Zn deposit mineralization theory and providing new ideas for mineralization prediction.

Features of electrical conductivity at high temperatures of complex titanomagnetite ores from the Gusevogorsky deposit

Relevance is determined by the search and selection of the most information-intensive characteristics and physical properties of complex titanomagnetite ores in connection with the need for scientifically based criteria for their detection, quality assessment during selective mining and selection of optimal enrichment technology. Research methodology. To study the electrical properties, samples in the shape of a cube with an edge of 0.02 m were used. The measurements were carried out in an open system at atmospheric pressure. Electrical resistance was measured with a two-electrode setup every 10 degrees in the temperature range 20–800 ºC. Heating rate 0.066 deg/s. The measuring device is an E6-13 teraohmmeter with a dynamic range from 10 to 1014 Ohms and a relative measurement error from ±2.5% to 4% at the end of the range. Results. A collection of samples of complex titanomagnetite ores from the Gusevogorsky deposit (Northern quarry) was studied using physical, mineralogical and petrographic methods. Functional connections have been established between the electrical parameters of high-temperature electrical conductivity (Eₒ – activation energy, lg Rₒ – the so-called electrical resistance coefficient), the value and nature of the electrical resistance lg R in the temperature range 20−800 °C of the studied samples of complex ores with their structural and textural features and mineral composition. Based on structural and textural features, mineral composition and electrical parameters, the studied samples are clearly divided into three groups. Conclusions. The presented results, in combination with other physicochemical parameters, can be used as a reliable indicator of rapid assessment of the material being studied. Significant differences in the electrical parameters of titanomagnetite ores provide additional information about their quality. In combination with other methods, we hope for the possibility of using these parameters in the selective extraction of ores that require different enrichment regimes.