Copper Ore Research Articles

A key feedback loop: building electricity infrastructure and electrifying metals production.

Energy infrastructure requires metals, and metals production requires energy. A transparent, physical model of the metals-energy system is presented to explore under what conditions this dependence constrains or accelerates the transition to a net-zero economy. While the mineral (as high as 340 Mt yr-1 iron ore, 210 Mt yr-1 limestone, 250 Mt yr-1 bauxite and 5.5 Gt yr-1 copper ore in the 2040-2050 decade, assuming no improvements) and total energy (up to 22 EJ yr-1) requirements for building low-carbon energy infrastructure are significant, it compares favourably with the current extraction and energy use supporting the fossil fuel system (15 Gt yr-1 fossil minerals and ~38 EJ yr-1). There are levers to significantly reduce material use and associated impacts over time. The metals industry can play a key reinforcing role in the transition by adapting to the increasing supply of renewable electricity. Specifically, direct electrolysis can extract metal from ore close to the thermodynamic limit, to make efficient use of low-C electricity. The unique features of emerging technologies for iron extraction, molten oxide electrolysis and molten sulphide electrolysis are considered in this evolving system. Electrification enables elegant separations and provides a pathway to build out infrastructure while reducing environmental impacts, though material efficiency measures will still be crucial to meet 2050 carbon budgets.This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

Exploitation of Mining Resources in El Argar Culture: Bronze Age Metallurgy in the Hinterland of the Western Betic Cordillera (Southeastern Iberian Peninsula)

ABSTRACTThis research addresses the territorial organisation of metallurgical production during the El Argar Bronze Age (2200–1550 cal bc) in the inner areas of El Argar territory through lead‐isotope and trace element analyses of geological copper ores, archaeometallurgical remains and copper‐based artefacts. Results from 31 mineral and 35 archaeological samples suggest that the exploitation of copper resources in the studied region was significant and had a similar impact than other mining districts of El Argar territory. This, therefore, leads the hierarchical and centralised production model to be questioned. It also appears that the copper ore deposits in the coastal regions that were intensively exploited during the Copper Age were used less intensively in the El Argar period. At that time, copper was mostly procured from ore deposits in the inland areas of El Argar territory: that is, ore deposits within the Alpine orogeny hinterland (inland areas of the Betic Cordillera, from Granada to Baza). Other artefacts were sourced from outside the Alpine geological domain, but still on the fringe of El Argar territory (the foothills of the Sierra Morena‐Linares mining district) or even from ore deposits definitely outside El Argar territory itself (the Los Pedroches Variscan region and elsewhere).

Spectroelectrochemistry study on the surface modification of chalcopyrite by Cu2+ and its depressive response to flotation collector adsorption by negative potential

In the flotation beneficiation of copper and molybdenum co-occurrence ores, the efficient depression of chalcopyrite is crucial for successful copper-molybdenum separation. However, the consumption of conventional depressant NaHS is huge. There is greater susceptibility of chalcocite and other secondary copper sulfide minerals to electrochemical reaction in comparison to chalcopyrite. Given the irreversible desorption behavior of collector molecules on chalcocite upon negative potential application, electrochemically regulated flotation can be effectively utilized to diminish the utilization of conventional depressants. In this work, electrochemistry and shell-separated nanoparticle-enhanced Raman spectroscopy (SHINERS) were used to explore the transformation of chalcopyrite surface to chalcocite-like species under the combined action of Cu2+ and negative potential. The results show that the similarity of cyclic voltammetry (CV) between the modified chalcopyrite and chalcocite, increases with the pretreatment potential becoming increasingly negative. Electrochemical impedance spectroscopy (EIS) also reflects their similar adsorption and desorption behavior in response to ammonium dibutyl dithiophosphate (ADD), a typical flotation collector molecule. In addition, the spectroelectrochemical directly reflects the irreversible desorption of ADD molecules from the modified chalcopyrite surface at − 0.7 V. The research results lay a theoretical foundation for the efficient Cu-Mo separative flotation by depressing chalcopyrite under the combination of Cu2+ and negative potential.

Discovery of live material of Marginella (Roseamarginella) namaqua

Recently (March 2024) the authors undertook another field trip to the Kalahari and northern West Coast of South Africa. In March 2021 the authors had an expedition through the Kalahari, Karoo and West Coast of South Africa that took them to a little-known fisher’s town, Hondeklip Bay. For background on the town, in 1846, Thomas Grace (a ship’s captain) discovered a small natural harbor and he established a trading station, naming the town after a gneiss rock which vaguely resembles a dog. The name of the town is “Hondeklipbaai”, an Afrikaans name that translates as “dog stone bay” in English. It became the preferred harbor of export for copper ore, until the harbor in Port Nolloth was developed in the 1850s. Alluvial diamond-mining operations started in the area in 1970 and constitutes the main business of mines in that area of the Northern Cape (Mohomed 2006). Just north of the Hondeklip Bay lighthouse a lesser-known bay is found, “Moordenaarsbaai”, where the study material that were used for describing the species was collected. Unfortunately, at that stage the authors could only spend one and a half day in the area, and no live material could be collected due to the neat tide and stormy seas. The recent trip to Hondeklip Bay by the authors did not disappoint, the tide timing was perfect with springtide and good weather. A bit of scratching between the rocks and sea grass in rough black-muddy sand revealed three live specimens. What makes this special is that this species so far only been found in this area and this is the first livematerial.

Separation of iron and copper in skarn deposits from the Yueshan ore field, eastern China: The control of magma physicochemical conditions

Iron and copper mineralization in the Yueshan ore field is intricately linked to the Cretaceous Yueshan diorite intrusions, yet they frequently materialize as distinct deposits. Despite this, the key factors dictating the segregation of these metals remain poorly understood. To gain insights into the role of magma physicochemical conditions in this segregation, we conduct a comparative analysis of the U-Pb dating, whole-rock geochemistry, and mineral chemistry of the newly uncovered Zhuchong skarn iron deposit (Fe:Cu ratio = 197) and the Anqing skarn copper deposit (Fe:Cu ratio = 35), both situated within the Yueshan ore field of the Middle Lower Yangtze River Valley Metallogenic Belt (MLYB) in eastern China. The garnet U-Pb dating of the Zhuchong and Anqing deposits are 138.3 Ma and 137.2 Ma, respectively, which are consistent with the zircon U-Pb dating (138.3 Ma) of diorites from the Zhuchong and Anqing deposit. The emplacement of diorite intrusions and Fe-Cu mineralization occurred at 137 – 139 Ma, consistent with the Cu-polymetallic mineralization epoch (145 – 137 Ma) in the MLYB. The diorite samples from the Yueshan intrusion and the Zhuchong and the Anqing deposits exhibit typical characteristics of adakites, such as high Sr/Y (28 – 174) and (La/Yb)N (26 – 40), along with similar and enriched Sr-Nd (εNd(t) = − 7.95 ∼ − 7.33) and zircon Hf isotope (−14.9 ∼ − 6.4) compositions. This suggests that the magma source regions for the diorites from the three locations were all likely derived from the melting of sediment-rich subducted oceanic crust with the potential of copper mineralization. However, chemical compositions of zircon, apatite, and amphibole from diorites reveal that diorites in the Zhuchong and Anqing deposits were emplaced at different depth levels and physicochemical conditions. Specially, the diorite in the Zhuchong Fe deposit was emplaced at shallower levels (1.9 km), with higher oxygen fugacity (mean = ΔNNO + 1.9) and fluorine concentration (2096 ppm), water deficiency (3.3 ± 0.4 wt%), sulfur-poor conditions (avg = 494 ppm), lower pressure (49.2 MPa), temperature (746 ℃), and chlorine (945 ppm) concentration relative to the Anqing Cu deposit (Emplacement depth: 2.53 km; oxygen fugacity: ΔNNO + 1.5; F: 1720 ppm; H2Omelt: 3.9 ± 0.4 wt%; S: 816 ppm; P: 66.9 MPa; T: 778 ℃; Cl: 945 ppm).It is proposed that a shallower emplacement depth may have promoted extensive exsolution of magmatic fluids, leading to the outward migration of water, S, Cl, and Cu elements, which resulted in the high iron-copper ratio observed at the Zhuchong Fe deposit. This process could have led to the relative Cl-poor nature and smaller Cu size at the Zhuchong Fe deposit, as well as the widespread development of vein-type copper ore bodies in the region.

Benefits and Vulnerabilities of the Free Trade Agreement for the EAEU Countries and China

Aim. Objective is to formulate the position of the EAEU in the negotiations on the free trade area with China.Tasks. We determine the potential results of the creation of the China-EAEU free trade area for each country.Methods. The indices of complementarity and trade intensity were calculated, and the benefits to society from the abolition of customs tariffs were calculated using a partial equilibrium trade-policy simulation.Results. The study of supply and demand for excavators showed that the total benefit of consumers (the construction industry) from the abolition of customs duties only slightly exceeds the losses of producers and the government. Based on the complementarity assessment, it was found that the free trade agreement is more beneficial for China than for the EAEU countries — the structure of China’s exports better corresponds to the structure of imports of the EAEU countries. It was revealed that the exports of the EAEU countries to China are not diversified, and the main export goods face minimal tariffs — 0% for crude oil from Russia and Kazakhstan, 3% for potash fertilizers from Belarus, 0% for ores and concentrates of precious metals from Kyrgyzstan, 0% for copper ores and concentrates from Armenia. The EAEU countries may be interested in further liberalization of trade with China due to the intention to export frozen fish, corn, wheat and rice (Russia), tobacco (Kyrgyzstan and Armenia), meat and dairy products (Belarus), and cognac (Armenia).Conclusions. Reduction of duties on the specified goods may be the subject of a preliminary temporary agreement. A free trade zone may be created by finalizing the existing Agreement on Trade and Economic Cooperation between the EAEU and its Member States and the PRC. It is recommended that, in addition to including provisions on the abolition of customs duties, sections on trade in services, investments, and movement of individuals be included.

Selective Sorption of Noble Metals on Polymer Gel Modified with Ionic Liquid.

The solid phase extraction of Au, Ir, Pd, Pt, and Rh on a polymer gel modified with ionic liquid containing methylimidazolium groups (MIA-PG) has been investigated. The positively charged surface of the sorbent is highly suitable for the sorption of stable chlorido complexes of the studied analytes, while the retention of base metals Cu, Fe, Ni, Zn, and Mn is negligible. Optimization experiments performed showed that, at 0.05 M HCl, the degree of sorption of Au, Ir, Pd, and Pt is above 95%, and only for Rh, the maximum degree is 65%; complete elution is achieved in the mixture of thiourea in HCl. The results obtained from the equilibrium adsorption studies are fitted in various adsorption models, such as Langmuir and Freundlich, and the model parameters have been evaluated. The kinetics analysis indicated that the adsorption of Au, Ir, Pd, Pt, and Rh onto the sorbent follows the pseudo-second-order model. Intraparticle diffusion and ion exchange reactions were the rate-limiting steps. Analytical procedures were developed for Pd, Pt, and Rh determination in road dust and soil and for Au determination in copper ore and copper concentrate. The procedures are validated by the analysis of certified reference materials. Analytical figures of merit confirmed their applicability in routine laboratory practice.

Assessment of different energy-based breakage distribution functions in population balance model of an industrial scale continuously operated wet stirred media mill

This study aimed at assessing various energy-based breakage distribution functions Bij within the context of a population balance model (PBM) of copper ore milling in a wet stirred media mill (WSMM). First, drop weight impact tests were performed to determine the size distribution parameters, tn. Second, various tn models called tn-fitted and tn-regenerated approaches were used to fit experimental tn, and their goodness-of-fits were compared. They were then used to construct the matrices of the cumulative breakage distributions, Bij, of the PBM, while a power-law form of the specific breakage rate function, Si, was assumed. By fitting the PBM to the product particle size distributions (PSDs) obtained under various rotor speeds, suspension volumetric flow rate, and solids content, we estimated the Si parameters. Results suggest that except the Napier-Munn model, all tn models fitted the experimental drop weight data reasonably well, which was reflected in the PBM fitting of the product PSDs. The PBM fits with Bij constructed with the tn-regenerated approach were more accurate than those with the tn-fitted approach. The PBM was validated with additional tests that were not considered in the parameter estimation. Overall, we have established that the choice of tn function and the methodology to determine Bij can affect the PBM predictions of the WSMM process significantly.

Compositional peculiarities of the primary, mixed, and oxidized copper ores in gabbroids of the Volkovsky massif (Middle Urals, Russia)

The Ural type magmatic copper deposits in gabbro are assigned to a specific type of copper deposits which exploitation substantially depends on the oxidation degree of the ores, that is often not unambiguous. At the Volkovskoe Cu-Fe-V deposit (Middle Urals, Russia), three technological grades of the copper ores are known, the primary, oxidized, and mixed ones, that are distinguished based on the relative content of Cu2+ in the total copper balance. This paper presents petrological, petrochemical, geochemical, and mineralogical characteristics of natural varieties of the copper ores of the Northwestern zone of the Volkovskoe deposit. It is demonstrated that the criterion for distinguishing the technological grades of the copper ores by the relative Cu2+ content does not reflect the real degree of the supergene oxidation for the selected technological varieties. The results of our research suggest a necessity of studying the copper sulfides in more detail to clarify peculiarities of the redox conditions of the ore formation, to correct the indicators of the primary and supergene copper oxidation degree, which may provide new criteria to determine the boundaries between the technological grades of copper ores, using the Volkovskoe ore deposit as an example.

Beyond linear narratives: Complex copper ore exploitation strategies in Early Bronze Age China revealed by geochemical characterization of smelting remains

Despite decades of efforts to reconstruct the bronze production and metal distribution systems of the Shang period in Bronze Age China, there remains limited understanding of the ore choices and smelting practices of the Shang people. This study addresses this research gap by conducting a detailed investigation of Shang period copper ores and smelting remains uncovered at the Tongling site in the Middle Yangtze River valley. The results of lead isotope, copper isotope, trace element, and rare earth element (REE) pattern help to classify the slags from this site into two groups, associated with smelting sulphidic (Group A) and oxidic (Group B) copper ores, respectively. This finding not only serves as the first physical evidence of the use of sulphidic copper ores in Early Bronze Age China but also provides pivotal details of the copper resource exploitation strategies of the Shang people. It challenges the traditional narrative that the Shang people moved to this area solely for the high-grade supergene deposits. The parallel use of both supergene and hypogene ores at the same site complicates the notion of a linear, technological evolution from simpler to more advanced copper sources. Despite the presence of hypogene ores, the study reveals that the Shang people maintained labour-intensive smelting practices, including crushing slag to recover trapped metallic prills, to meet the demands of large-scale bronze casting. This nuanced approach to copper resource exploitation reflects a complex, context-dependent strategy rather than a technological revolution. By highlighting these intricate metallurgical choices, this research contributes to a broader rethinking of early technological development, underscoring the diversity and adaptability of ancient craft industries and their role in shaping Shang society.

Statistical Evaluation of Flotation Behavior of Chalcopyrite in the Presence of SIPX and Acetoacetic Acid n-Octyl Ester as a Novel Collector Blend: A Sustainable Approach

The chalcopyrite deposit in Malanjkhand, India, is the largest copper ore producer in the country. However, its flotation performance has room for improvement. This study used standard flotation experiments using a mechanical flotation cell using a conventional collecting reagent and a collector blend consisting of xanthate and ester. A three-factor, three-level Box-Behnken design was used to statistically evaluate the experimental design. The obtained data were analyzed using an ANOVA, cubic plots, and response surface methods. The goal was to evaluate the effects and interactions of three key process parameters in chalcopyrite flotation: the dosages of sodium silicate (depressant), sodium isopropyl xanthate (collector), and acetoacetic acid n-Octyl ester (co-collector/modifier). The results implied that introducing acetoacetic acid n-Octyl ester along with minor tweaks in the dosages of sodium isopropyl xanthate helped increase copper grades by at least 15%, with good recovery percentiles. Among the three parameters tested, the copper’s grade and recovery were considerably positively influenced by the AoE dosage in the collector blend. Employing 0.006 kg/t sodium silicate and 0.0065 kg/t sodium isopropyl xanthate with 0.005 kg/t of acetoacetic acid n-Octyl ester, an optimum copper recovery of 88.87% could be achieved. However, with a sodium silicate dosage of 0.0048 kg/t, a SIPX dosage of 0.008 kg/t, and an AoE dosage of 0.005 kg/t, optimized copper grade (1.55%) could be achieved, which is a 78.1% increase from the feed sample grade. To validate the expected results, verification experiments were carried out, and the experimental findings were found to be on at par with the statistical model predictions. Furthermore, the calculated SPI value of 0.0000147cap Kg−1 for a global index per resident lies between 0 and 1.

INNOVATIVE METHODS FOR PROCESSING COPPER ORES IN KAZAKHSTAN: A COMPREHENSIVE APPROACH TO ENHANCING THE EFFICIENCY OF VALUABLE COMPONENT EXTRACTION

This article presents an innovative approach to processing copper ore from one of the deposits in Kazakhstan, aimed at enhancing the efficiency of copper extraction from materials with a complex mineral composition. The described methodology includes several key stages: comprehensive analysis of the ore's material composition, gravity and flotation beneficiation, as well as hydrometallurgical processes. During the study, the ores underwent preliminary preparation, including crushing and grinding to the required fineness. Experiments on gravity and flotation beneficiation demonstrated that optimizing the parameters of these processes significantly increases the yield of copper concentrate. Additionally, sulfuric acid leaching conducted showed high efficiency in extracting copper from the ground ore. The research results confirm that a comprehensive approach to copper ore processing ensures high efficiency in extracting valuable components and opens up prospects for the sustainable and economically viable utilization of complex copper ores

Achieving enhanced power factor using dual substitution at Cu and S sites in tetrahedrites thermoelectric materials Cu12Sb4S13

Thermoelectric (TE) materials-based devices are valuable for translating heat into electricity, but the cost is largely driven by the use of purified metals required for efficient TE performance. This study focuses on tetrahedrite materials, which are cost-effective due to their abundance in copper ore mining waste and status as one of the most widespread sulfosalts on Earth. The research investigates the effects of co-doping and iso-valent doping on the TE properties of p-type tetrahedrite samples, specifically Cu10Mn2Sb4S11Se2 (Sample A) and Cu10MnZnSb₄S11Se2 (Sample B). These samples were synthesized using hot pressing at 773 K and compared with the existing pristine compound (Cu10Mn2Sb4S13). Doping with Mn and Zn (1:1) at the Cu site was found to optimize carrier concentration and enhance phonon scattering, leading to an improved power factor. Additionally, the Se substitution at the S site also introduced band degeneracy, further increasing the power factor. Further, sample B exhibited the highest Seebeck coefficient (∼300 μV/K) at 650 K, in comparison to Sample A (∼225 μV/K) and the pristine compound (∼250 μV/K). On the other hand, Sample A demonstrated significantly higher electrical conductivity (∼0.76 × 10⁴ S/m at 650 K), ∿ three times greater than that of the other prepared samples. Notably, the power factor of Sample A (∼0.389 mW/mK2 at 650 K) was more than twice that of Sample B (∼0.141 mW/mK2) and the pristine compound (∼0.160 mW/mK2). These findings suggest that dual-site substitution at the Cu and S positions presents a promising strategy to augment the TE performance of tetrahedrite compounds.

Reconstructing the invention of the wheel using computational structural analysis and design

The invention of the wheel is widely credited as a pivotal moment in human history, yet the details surrounding its discovery are shrouded in mystery. There remains no scholarly consensus on key questions such as where, how and by whom this technology was originally invented. In this study, we employ state-of-the-art techniques from computational structural mechanics to shed light on this long-standing puzzle. Based on this analysis, we propose a probable path along which the wheel evolved via a sequence of three major innovations. We also introduce an original computational design algorithm that autonomously generates a wheel-and-axle system using an evolutionary process that offers insight into the way in which the first wheels probably evolved nearly 6000 years ago. Our analysis provides new supporting evidence for the recently advanced theory that the wheel was probably invented by Neolithic miners harvesting copper ore from the Carpathian Mountains as early as 3900 BC. Moreover, we show how the discovery of the wheel was made possible by the unique physical features of the mine environment, whose impact was analogous to the selective environmental pressures that drive biological evolution.

Development of a methodology for prediction and calibration of parameters of DEM simulations based on machine learning

This research work aims to develop a robust methodology for the global estimation of interaction parameters based on machine learning, applicable to the discrete element method (DEM) in the study of granular materials. The specific objectives include establishing a theoretical framework that relates the interaction micro-parameters with the macro-parameters and the physical behaviour of the material; performing DEM simulations for different material parameters; developing a machine learning-based model for global parameter estimation; and consolidating the methodology for obtaining micro-parameters for a given material and behaviour. The methodology will be applied specifically to the case of dry copper ore, evaluating its limitations and the possibility of extension to materials with other characteristics. This approach does not consider direct experimental tests, but focuses on the characterisation of the relationship between the input parameters of the material and its response through simulations, validating the response and sensitivity of the model in its different stages. The methodology is expected to allow the systematic estimation of interaction properties for a DEM model, considering micro-parameter duplicities and their global selection, aspects little addressed in the literature. The final verification includes mechanisms and key questions that facilitate future modifications and improvements, allowing its application to materials of different characteristics beyond the specific case study.

Application of ultrasound for leaching Vietnamese monazite concentrate with NaOH solutions to obtain chlorides of rare earth elements

Relevance. Despite the use of alkali stripping technology for processing monazite concentrate in industry, this method has a number of limitations, such as low efficiency of concentrate stripping, the need to use a large excess of alkali and a long process time. Aim. Improvement of existing technology to overcome these limitations. Methods. Fusion with NaOH under pressure and fusion with NaOH combined with ball milling, as well as fusion with NaOH using high intensity ultrasound. High-intensity ultrasound has long been studied and used in industry to intensify leaching/alloying in various applications to increase efficiency and speed in leaching for copper, vanadium, nickel, bauxite and uranium ores. This article is devoted to studying the influence of high-intensity ultrasound on the efficiency of opening monazite concentrate with NaOH solutions. Experimental data were obtained using mass spectrometric, X-ray diffraction and ICP-OES analysis methods. Results and conclusions. The optimal conditions for leaching batches of samples weighing from 100 g to 1 kg were determined. The authors have carried out the research on the separation of radioactive elements and impurities in a solution of rare earth chlorides, obtaining a solution of rare earth chlorides purified from radioactive components and impurities. It was shown that ultrasonic exposure eliminates the disadvantages of traditional fusion technology with NaOH, which can be used for deep processing of Vietnamese monazite concentrate. The conditions for obtaining REE chlorides from a previously opened monazite concentrate are given.

Lithophysical characteristics of productive strata of cupriferous sandstone within Zhezkazgan ore district in the Central Kazakhstan

Purpose. The paper concerns additional geological appraisal and identification of extra localization criteria of cupriferous mineralization of a stratiform type. The research is intended to define physical and geological factors influencing sandstone distribution within the north-end of Zhezkazgan synclinal in the Central Kazakhstan. Methods. A complex analysis of geological and mineralogical, geophysical, and geochemical data was carried out relying upon the information obtained from deep-hole wells. Modern methods to process and interpret the field data were applied. The analysis involved lithological dismemberment of the productive Taskuduk suite as well as determination of sulfide mine-ralization zone boundaries. Findings. The research has shown that the productive levels reach down to 1500-m depth. The data interpretation has helped specify the geological structure and develop a model of ore-promising bodies of cupriferous sandstones at great depth. The applied complex data analysis has increased potential to prospect new loci of productive cupriferous sandstone deposits of Zhezkazgan type. Originality. The research has contributed significantly to understanding of the physical and geological factors influencing the copper ore distribution in deep layers. New physical and geological criteria, determining deep copper mineralization localization, have been identified which were not considered by earlier similar studies. Practical implications. The obtained new data as well as the developed methods are important while deep drilling planning and implementing to identify promising copper mineralization sites. The findings may be used to optimize exploration within the north-end of Zhezkazgan synclinal, and other districts having analogous geological conditions.

ПЕРВЫЕ СВЕДЕНИЯ О МЕДНОЙ МИНЕРАЛИЗАЦИИ РУДОПРОЯВЛЕНИЯ ШАРОМСКОЕ, ЦЕНТРАЛЬНАЯ КАМЧАТКА

The report provides new data on the mineralogy of the ores of the Sharomskoye copper ore occurrence, the Kirganik-Sharom ore zone in Central Kamchatka. Copper ores are confined to the central part of the submeridional massif of subalkaline metasomatites. Mineralization is disseminated, less often vein-disseminated in nature.The studied ore samples, collected during field works in 2023, are represented by silicified metasomatites with developed sulfide mineralization. Among the vein and accessory minerals are quartz, chlorite, barite and apatite. Ore minerals are represented by magnetite, chalcopyrite and bornite. Hematite and malachite are the most common supergene minerals, while cuprite and hydroxides of Fe and Cu are less common. The established chalcopyrite-bornite mineral association of the Sharomskoye ore occurrence is considered typical of other copper mineral prospects in central Kamchatka and is characteristic of porphyry copper deposits.

Trace and Minor Element Analysis of Azurite Blues in Fine Arts: Possibilities and Limitations in Provenance Studies.

Azurite, a historical blue mineral pigment, has previously been described to contain certain elemental impurities. These may originate from host rocks, vein fillings, or the primary copper ore mineralization. In this study, azurites (and also green malachites) from three important Central European deposits with a potential of being exploited for pigment usage already in the Middle Ages have been studied, together with azurite from Chessy, France, with a different geological setting. Using electron probe microanalysis and, more importantly, laser ablation inductively coupled plasma mass spectroscopy for trace elemental analysis, several indicators were pinpointed as important for provenance: characteristic elemental fingerprint of the deposit, e.g., elevated lead (Pb) in combination with rare earth elements, may be combined with zinc (Zn)/arsenic (As) ratio (indicating sources of excess Zn in the primary deposit) and the overall amount of metal impurities (suggesting the source mineral of copper for azurite formation). In addition, malachites from the same deposits were found to preferentially incorporate primary ore metal elements as well as Cd, Mg, Mn, or U. Therefore, if azurite pigment contains an elevated amount of malachite as an impurity, it may significantly influence the overall elemental composition. The results obtained on geological samples were applied to two micro-samples of works of art containing azurite-rich layers originating from the 13th-14th and 16th centuries. It was shown that it is highly beneficial to focus on the overall trace elemental composition of the paint layer and not on the admixed mineral grains, as their presence, especially in minute micro-samples, is largely accidental and thus not representative. Although a higher number of samples need to be studied in the future, the newly described criteria made it possible to exclude some of the localities of the employed azurite pigment. This confirmed the key importance of trace elements analysis of mineral pigments for the provenance studies of fine arts.

Impact of the feed particle size distribution and its packing characteristics on compression comminution

Due to its lower energy consumption than a conventional grinding circuit, there is an increased interest in the mining industry in the High-Pressure Grinding Rolls (HPGR) technology. Despite the benefits, the high quantity of material required to size the HPGR makes it difficult for new mines to consider this technology. The piston press test has been used at The University of British Columbia to predict the behavior of the HPGR. It is possible to predict energy requirements, size reduction, and throughput by utilizing a small amount of material to size the HPGR. The bulk material’s particle size distribution (PSD) plays an important role in how the particle bed will pack. This study investigates the differences in compressing three different sample PSDs obtained from the same copper ore crushed to −12.5 mm. The first PSD corresponds to the natural distribution resulting from the crusher. The second is created artificially to match the Fuller curve PSD, which theoretically should have the highest packing density. The third corresponds to a truncated feed produced by removing the fines (−300μm) from the natural feed. Tests were performed using a piston-and-die press test apparatus to compress the samples at different force levels. Entirely different behaviors are obtained while compressing the same material with different PSDs. Particularly, the Fuller curve PSD achieves a 31%–40% higher grinding rate than the natural feed, while the truncated feed achieves a 9%–30% higher grinding rate than the natural feed. Differences in the specific energy consumption, grinding efficiency, and final compacted densities highlight the critical influence of feed particle size distribution on the energy usage and generation of fine particles, underscoring the importance of optimizing these parameters for energy-efficient mineral processing. The overall findings indicate that an HPGR feed particle size distribution that matches the Fuller curve and, therefore, has a maximum packing density, results in the most energy-efficient comminution.