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Efficient development and utilization of low-grade copper ore are essential for ensuring a stable supply of copper resources. Focused on a low-grade copper ore from Yunnan, detailed process mineralogy studies were conducted to determine the occurrence state of copper minerals. Moreover, a tailored flotation process and reagent regime were developed for this ore based on flotation condition tests and the locked-cycle tests. The results indicate that the ore contains 0.31% copper, with 93.55% of the copper being in sulfides, primarily in the form of chalcopyrite. The copper minerals are finely dssseminated within gangue minerals. During the rougher stage, the use of a non-polar collector CM3 can significantly improve the grade of rough concentrate while ensuring copper recovery. The collector Z200 is the proper collector used in scavenger stage for further enhancing copper recovery. A copper concentrate with copper grade of 23.03% and recovery of 86.97% was obtained in the laboratory locked-cycle test under the condition that the grinding fineness of -74 µ m being 72% and the flowsheet of one roughing, two cleanings and three scavengings being adopted. The results can provide reference for the efficient flotation recovery of low-grade copper ore in China. [ABSTRACT FROM AUTHOR]

Mining activities can lead to an exacerbated enrichment of metal concentrations. Pollution by metal(loid)s in arid regions has been little elucidated. This study assessed the transport and mobilization of trace elements in an arid environment under two ephemeral wash systems originating from processed tailing materials in the Valley Wells Smelter, California (USA). Overall, enrichment factors evidence a significant increase in trace elements in the South Wash compared to the North Wash. The Principal Component Analysis demonstrates in the South Wash that Cd-Cu is associated with As-Pb-Zn and Ba-Co-Mn primarily. All areas (from South and North wash) indicated extremely high enrichment of Cu due to mining activities. Data showed that in the northern wash area the metals As, Cu and Sr presented concentrations much higher than the background. The geochemical survey indicates deleterious effects on the environmental quality of the investigated areas, requiring reparative and conservative measures. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical looping combustion (CLC) has been validated as one of the most promising technologies for fossil fuel combustion, which can produce high-purity CO2 streams ready for capture and sequestration in power production. The selection of an appropriate oxygen carrier is one of the most important issues for the CLC process, and the reduction kinetics investigation of the oxygen carrier with fuel gas can provide the basis for CLC reactor design and simulation optimization. In this study, copper ore was chosen as an oxygen carrier, and the oxygen release property of copper ore under a nitrogen environment at various temperatures (1073–1193 K) was first investigated in a thermogravimetric analyzer (TGA). Subsequently, the reduction kinetics of copper ore with CO and H2 were evaluated by the TGA at temperatures ranging from 773 K to 1073 K, using a continuous stream of 5, 10, 15, 20, 25, and 30 vol. % of CO or H2 balanced by CO2 or N2. It was found that the reaction rates of these reactions accelerated with the increase in temperature and fuel gas concentration in inlet gas. Both the oxygen release process of copper ore and the reduction process of copper ore with reducing gases can be described by the unreacted shrinking core model (USCM). The reaction mechanism function for the oxygen-releasing and reduction process of copper ore oxygen carrier was varied. The activation energy of the oxygen-releasing process, reduction process with CO, and reduction process with H2 were calculated as 99.35, 5.08, and 4.28 kJ/mol, respectively. The pre-exponential factor ranged from 1.96 × 10−1 to 1.84 × 103. The reaction order depended on the fuel gas, which was 1 and 0.86, respectively, for reaction with CO and H2. [ABSTRACT FROM AUTHOR]

The present article emphasizes the influence of forest vegetation on improving the content of toxic elements from soil, increasing the content of micro and macro elements as well as correlating these variations with characteristics of forest vegetation from the studied areas—Moldova Nouă waste heaps, South-West Romania. The research involved comparing and observing the differences in the content of micro, macro, and toxic elements (Fe, Pb, Zn, and Cd) between the soil of waste heaps from Moldova Nouă from areas with forest vegetation and the content of these elements analyzed 31 years ago during the projection of afforestation works, when forest vegetation was missing. The differences were correlated with stand characteristics of forest vegetation. We observed a significant increase for Fe and a significant decrease for Zn and Cd. The influence of forest vegetation of the variation on the soil's chemical composition was studied for the chemical elements that previously showed significant differences (Fe, Zn, and Cd). The averages of the statistically significant differences for the concentration of each analyzed element (Fe, Zn, and Cd) were correlated with the characteristics of the stands from the studied sampling points. The variation in time for Fe, Zn, and Cd and actual content of P, Cu, Mg were correlated especially with the average height of trees. [ABSTRACT FROM AUTHOR]

In order to fully understand the properties of a certain copper ore and develop a reasonable beneficiation process, a comprehensive analysis was conducted using chemical multi-element analysis, optical microscopy, MLA, and other methods to analyze the chemical composition, mineral types, structural characteristics, embedded features of the main minerals, and occurrence status of the main useful elements in the ore. It was found that the main useful elements in the ore were Cu and S, with grades of 1.73% and 20.81% respectively, as well as associated precious metal elements Au and Ag, with grades of 0.63 g/t and 5.46 g/t respectively. The main copper minerals were chalcopyrite, followed by tennatite and tetrahedrite, and the grain sizes of the copper minerals were above 0.020 mm and below 0.147 mm, mainly embedded in sulfide and vein minerals. The metal sulfides were mainly pyrite, with particle sizes mainly above 0.043 mm and below 0.417 mm, requiring fine grinding for individual dissociation during beneficiation. The gold minerals were mainly native gold and electrum, mainly in the form of fine particles, embedded in sulfide and vein minerals with a complex intergrown relationship and a relatively high difficulty in recovery. The distribution of silver elements was relatively scattered, most distributed in pyrite and copper minerals. Based on these results, it is recommended to use the "copper -- sulfur bulk flotation -- copper--sulfur separation flotation process" to process the copper ore, and to separate the bulk copper -- sulfur concentrate after re-grinding. Gold and silver can be recovered respectively in copper concentrate, sulfur concentrate, and tailings. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bányászati és Kohászati Lapok - Kohászat is the property of Hungarian Mining & Metallurgical Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gallium, indium, cadmium, selenium, tellurium, germanium, thallium and other rare disperse elements are often present in copper deposits, and accurate analysis of these elements is beneficial to comprehensive utilization of minerals. The determination of Ga,Ge,In,Tl,Se,Te and Cd in copper ore by microwave digestion and inductively coupled plasma mass spectrometry was established. The symmetric sample size, acid system, ethanol concentration, microwave digestion work conditions and mass spectrum interference were optimized. The results show that under optimized conditions, the linear correlation coefficient of the calibration curve is greater than 0. 999 5, and the detection limit is 0.002~0. 19, µg/g. The relative standard deviations (RSD, n = 6) are 2. 63%~13. 84%, and the standard recoveries are 90. 4%~110. 6%. The method is accurate and reliable, and the results are consistent with the standard method. [ABSTRACT FROM AUTHOR]

Efficient and eco-friendly technologies are required to reduce the environmental effects of the beneficiation plants. Recently, there has been an interest in environmentally friendly alternative depressants. This study explored the effects of various depressants (AERO633, AERO7260, DP3124, DP3125, carboxymethyl cellulose (CMC), Cyquest4000, and sodium silicate) on chalcopyrite flotation. The experimental results indicated that AERO7260 has the best effect on chalcopyrite flotation, and the dosage is 50 g/t, it can improve the chalcopyrite recovery up to 93.35% as well as chalcopyrite grade up to 36.97%. Meanwhile, AERO7260 had an obvious depression effect on pyrite, reducing pyrite grade to 61.10% and pyrite recovery to 3.35%. Given its low reagent dosage and high selectivity, AERO7260 is a promising depressant that can be used for chalcopyrite flotation. The use of organic depressants will significantly aid the transition to ecologically friendly and sustainable processes. This study shows that organic depressants in chalcopyrite flotation can replace the existing inorganic depressants used in the depression of gangue minerals and that metals can be recovered at high performance by processing appropriately. [ABSTRACT FROM AUTHOR]

Chemical looping combustion (CLC) has been validated as one of the most promising technologies for fossil fuel combustion, which can produce high-purity CO2 streams ready for capture and sequestration in power production. The selection of an appropriate oxygen carrier is one of the most important issues for the CLC process, and the reduction kinetics investigation of the oxygen carrier with fuel gas can provide the basis for CLC reactor design and simulation optimization. In this study, copper ore was chosen as an oxygen carrier, and the oxygen release property of copper ore under a nitrogen environment at various temperatures (1073–1193 K) was first investigated in a thermogravimetric analyzer (TGA). Subsequently, the reduction kinetics of copper ore with CO and H2 were evaluated by the TGA at temperatures ranging from 773 K to 1073 K, using a continuous stream of 5, 10, 15, 20, 25, and 30 vol. % of CO or H2 balanced by CO2 or N2. It was found that the reaction rates of these reactions accelerated with the increase in temperature and fuel gas concentration in inlet gas. Both the oxygen release process of copper ore and the reduction process of copper ore with reducing gases can be described by the unreacted shrinking core model (USCM). The reaction mechanism function for the oxygen-releasing and reduction process of copper ore oxygen carrier was varied. The activation energy of the oxygen-releasing process, reduction process with CO, and reduction process with H2 were calculated as 99.35, 5.08, and 4.28 kJ/mol, respectively. The pre-exponential factor ranged from 1.96 × 10−1 to 1.84 × 103. The reaction order depended on the fuel gas, which was 1 and 0.86, respectively, for reaction with CO and H2.

The present article emphasizes the influence of forest vegetation on improving the content of toxic elements from soil, increasing the content of micro and macro elements as well as correlating these variations with characteristics of forest vegetation from the studied areas—Moldova Nouă waste heaps, South-West Romania. The research involved comparing and observing the differences in the content of micro, macro, and toxic elements (Fe, Pb, Zn, and Cd) between the soil of waste heaps from Moldova Nouă from areas with forest vegetation and the content of these elements analyzed 31 years ago during the projection of afforestation works, when forest vegetation was missing. The differences were correlated with stand characteristics of forest vegetation. We observed a significant increase for Fe and a significant decrease for Zn and Cd. The influence of forest vegetation of the variation on the soil’s chemical composition was studied for the chemical elements that previously showed significant differences (Fe, Zn, and Cd). The averages of the statistically significant differences for the concentration of each analyzed element (Fe, Zn, and Cd) were correlated with the characteristics of the stands from the studied sampling points. The variation in time for Fe, Zn, and Cd and actual content of P, Cu, Mg were correlated especially with the average height of trees.

Permeability reduction is a major challenge in heap leaching, primarily caused by the accumulation of fines that move with the leaching agent, leading to the formation of dead zones and channeling within the heap. In the Aria copper beneficiation plant, the 0-2 mm fraction with a copper grade of 1.4% undergoes pre-separation prior to heap loading without further processing. This study investigated the potential of using the agglomeration method to improve permeability in the case of using the 0-2 mm fraction of ore. Mineral compounds, such as sodium silicate and calcium sulfate, and non-ionic, cationic, and anionic polymer compounds, were used in the agglomeration process. The strength of interparticle bonding was evaluated by measuring the fine migration percentage (FMP) in the soak test. The results revealed that agglomerates produced using non-ionic compounds had the highest bonding strength, with an FMP of 3.89%, the lowest of all the compounds tested. This enhanced bonding strength was attributed to the combined influence of hydrogen bonding forces and van der Waals forces. [ABSTRACT FROM AUTHOR]

The optimization of recovery of copper from Akiri hematite-dominated copper ore using hydrometallurgy was investigated in this study. The Akiri copper ore deposit hosts a high-grade copper mineral from which copper metal can be extracted. However, the ore is dominated by gangue minerals that need to be mechanically reduced for efficient copper recovery. The purpose of this study is to optimize the extraction of the metal from hematite-dominated copper ore. The experiments that were carried out in the course of this study include crushing, pulverization, mineralogical and chemical characterizations of the sample and sulpheric acid leaching. Response surface methodology was used to optimize the system parameters namely;temperature, concentration of the leachant and contact time so that an efficient method will be developed for the extraction of copper. Chalcopyrite, covellite and cuprite are the copper minerals while the gangues minerals were quartz, mica, hematite, etc. on the characterization of the copper ore. The major oxides in the ore are hematite, copper oxide and silica and revealed that the ore contains 4.61% copper and 65.8% iron. Effect of three independent factors like concentration, temperature and contact time for copper extraction from the hematite-dominated copper ore was studied. Central composite design method was applied to the proposed quadratic model that connect the factors used for best copper extraction at the best process condition. The work shows that concentration of the acid was the best efficient factor for copper extraction compare to temperature and contact time. This may be as a result of high value of F-statistics for the concentration of the leachant, which effects to high level of copper extraction. Experimental and predicted values for weight loss from the copper ore were obtained as 39.10% and 39.03% at optimum conditions, respectively. The optimum conditions of 1.5M acid concentration, 90oC reaction temperature and 90minutes contact time were obtained and from which 6.64%Cu at recovery of 92.0% and 2.31%Fe was obtained without stirring. Also, the ore was subjected to leaching with stirring at 400rpm with the optimum conditions obtained to know the effect. The grade obtained was 7.84%Cu at recovery of 83.51% and iron content 5.47%. This shows that leaching without stirring is the best option against leaching with stirring to extract the copper and to reduce the iron and other gangues contents in the copper ore. The activation energies were estimated as 13.20kJ/mol and 22.67kJ/mol for liquid film diffusion and diffusion product layer respectively, the values indicate that the leaching rate is controlled by diffusion process. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the effects of metal mineralization and mine operation on surrounding ecological environment and human health, 69 farmland soil samples of study area were collected, tested with seven heavy metals and analyzed with environmental risk assessment, spatial distribution, and source identification. The Igeo values of Cu and Pb indicated light-moderate pollution level and Co belonged to moderate pollution level. The EF values of Co represented moderately severe enrichment level, and Cu and Pb belonged to moderate enrichment level. The Er i values were in decreasing order of Co>Cu>Pb>Cr>Zn>Mn>Fe, moreover both Er i and RI values of seven heavy metals were at low ecological risk level. The spatial distribution of Fe, Zn, Cr and Mn showed a trend "high in northwest and low in southeast", and Co and Cu were similar with the characteristics "the closer to Chating copper ore, the higher the value", and points with higher content for Pb were distributed along the roads beside Gucheng Lake and irrigation canal. Pearson correlation analysis (CA), hierarchical cluster analysis (HACA), and principal component analysis (PCA) were adopted to gradually identified the characteristics, interactions, classifications and possible sources. PC1 was explained by Fe, Cr, Mn and Zn and might be the natural source influenced by the crust and soil parent material; PC2 was dominated by Pb and Zn and might be derived from transportation and mechanical operations; PC3 was loaded by Cu and might be greatly affected by copper mining activities. [ABSTRACT FROM AUTHOR]

The high-pressure grinding roll (HPGR) has been known to achieve a high mineral liberation with relatively low energy consumption. However, quantitative methods for evaluating the effect of HPGR grinding on the promotion of the mineral liberation of copper ores have not been fully established. This study aims to establish a quantitative evaluation of promoting the liberation ratio of copper minerals by HPGR grinding. We performed clack observation using the combination of the paint penetration method and the mineral liberation analyzer (MLA). Direct clack observation reveals that HPGR grinding can promote the formation of cracks in the product particles. The liberation ratio of copper minerals is related to the percentage of cracks in the product particles. Besides, the grinding tests using a laboratory ultra-small scale showed that the liberation ratio of copper minerals became larger than that of the ball milling alone. In all conditions where HPGR grinding was conducted before ball milling, the ball milling time became almost half that of the ball milling alone. The grinding kinetic constant of the HPGR milling product in ball milling is also determined. The grinding kinetic constants for 80% passing particle size in HPGR grinding products are larger than that in feed ores, and they are consistent with the trend of ball milling time. This might be because the HPGR milling causes cracks in the particles, which are more easily ground in the subsequent ball milling. Consequently, this study demonstrates that the ratio of clacks and the grinding kinetic constant in the ball milling process after HPGR milling can be used as an index to quantitatively evaluate the effect of HPGR milling on promoting the liberation of copper minerals.

The moisture of bulk material has a significant impact on the energetic efficiency of dry grinding, resultant particle size distribution and particle shape, and conditions of powder transport. This research aims to develop computer vision and thermovision techniques for the on-site estimation of moisture content in copper ore, for use, e.g., in dry grinding installations. The influence of particle size on the results of moisture estimation is also studied. The tested granular material was copper ore of particle size 0–2 mm and relative moisture content of 0.5–11%. Both vision and thermovision images were taken at standard and macro scales. The results suggest that median-intensity vision images monotonically reflect copper ore moisture in the range of about 0.5–5%. Suitable models were identified and cross-validated here. In contrary, thermograms should not be analyzed simply for their mean temperature but treated with computer vision processing algorithms. [ABSTRACT FROM AUTHOR]

Since the start-up of the Sossego copper concentrator, located in the Carajás Mineral Province in the southeast of Para State, Brazil, the low-grade ore (~0.34% Cu) has been stockpiled, as defined in the long-term mine plan, to be reclaimed at the end of the mine life. Given this imminent need to process around 40 Mt of this low-grade ore, questions have been raised related to the extent of oxidation that might have occurred in this stockpiled ore. In this context, a study was designed to characterize the stockpiled ore and assess the effect of the ore oxidation on its flotation response. A sampling campaign of the stockpiled ore was carried out to analyze the main variables that could influence the level of oxidation, and, consequently, copper recovery, such as stockpiling time, depth, and particle size. The results showed that there are two main factors negatively impacting the copper recovery of the low-grade stockpiled ore: the surface oxidation and the level of liberation of the copper mineral. Depth and period of stockpiling were not found to influence the level of oxidation, nor the flotation response. An empirical model was proposed for the copper recovery in the rougher stage, which resulted in a predicted value of 90.7%, which was lower than that for the fresh (and higher copper content) ore fed to the plant (93%). [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. • Challenging linear narratives of technological progression of ore exploitation strategies in Early Bronze Age China. • Presenting the first direct evidence of hypogene ore exploitation in Early Bronze Age China. • Reconstructing the style Shang copper production industry, contrasting sharply with that of Shang bronze casting. • Developing a new methodological toolkit for slag analysis, employing multiple geochemical proxies. [ABSTRACT FROM AUTHOR]

Crosswell electromagnetic (EM) methods are widely used in subsurface geophysical prospecting because they can achieve more effective long-distance detection than single-well methods. However, a large-diameter borehole is required to increase the magnetic moment of the magnetic dipole source. For the long-distance detection of copper ores, which is usually performed in slim holes, we present a borehole-surface current-injection-based crosswell EM logging method. Considering the cost of deploying casing, we inject a low-frequency ac directly into the ground, and converging current is formed around low-resistance anomalies in the formation. Then, the distribution of the anomalies can be inferred by detecting the low-frequency alternating magnetic field of the converging current in the receiver well. Moreover, to further improve the detection performance, we design a placement scheme for the grounding electrode for multianomaly crosswell detection based on the Gauss–Newton inversion algorithm, where the EM responses for different grounding electrode locations are analyzed. Field experiments are conducted using two slim open holes spaced approximately 1000 m apart for the detection of two copper ores. Through the processing and interpretation of measured EM signals, the conductivity imaging results of the crosswell EM method indicate that the measured distribution of anomalies is consistent with prior knowledge obtained from numerous single-well loggings, demonstrating the feasibility of the proposed application for long-distance crosswell EM logging in slim open holes.

A simple procedure for the synthesis of magnetic hybrid nanoparticles (MHNP) was developed by combining multi-walled carbon nanotubes modified by microwave energy and magnetic iron oxide nanoparticles. MHNP were introduced as sorbents in a magnetic solid phase extraction methodology for the total Arsenic determination in copper ore samples. Arsenic is penalized contaminant element in copper ores. Arsenic was determined by electrothermal atomic absorption spectrometry with a reduced temperature program. Arsenic adsorption corresponded to 96 - 104%, at ug g−1 levels. After a variable screening stage using a Placket-Burman (PBD) experimental design, the developed methodology was optimized using a Box-Behnken experimental design. Based on the optimal working parameters, a detection limit of 30 ng L−1 was reached, with a relative standard deviation of 7.1% and a preconcentration factor (PF) of 50. The Certified Geochem Base Metal Reference Material Product Code GBM900-10 was analyzed for the validation stage.

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrometallurgy of China is the property of Hydrometallurgy of China Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Solstad copper deposit, located in SE Sweden, is hosted by a quartz-rich rock sliver surrounded by a granite belonging to the 1.8 Ga Transscandinavian Igneous Belt. Ore petrographic studies have revealed a number of previously unrecognized opaque phases, including several Co phases, selenides and tellurides. Based on an in situ U-Pb investigation of zircons from a mineralized sample, it is suggested that zircons have a detrital origin and that the quartz-rich host rock is a xenolith belonging to the c. 1.88–1.86 Ga Västervik quartzite formation. A low-radiogenic galena sample implies that the source for the metals in the ore has a primitive origin, probably the basaltic lavas (now amphibolites) that are intercalated in the Västervik quartzite. Fluid inclusion studies in quartz distinguish four distinct ore fluids: (1) a hypersaline halite-bearing aqueous fluid related to an early (1.85–1.86 Ga) chalcopyrite depositional stage, (2) a subsequent CO2-rich fluid, that deposited native gold, tellurides, selenides and bismuthinite, developed (at ≥1.8 Ga) as a result of a phase separation, (3), a moderate- to high-salinity aqueous fluid did also develop at this event and led to the deposition of bornite and (4) a concluding, low-salinity aqueous fluid stage (at ≤1.8 Ga) caused oxidation to covelline and digenite of previously formed phases. It is proposed that the Solstad deposit and other Cu ± Co-rich sulphide (± magnetite) occurrences in the Västervik region along the southernmost margin of the 1.9–1.8 Ga Svecofennian Domain, represent a distinct ore type associated with quartzites and amphibolites. [ABSTRACT FROM AUTHOR]

LCA (Life Cycle Assessment) is a useful tool in decision-making for most businesses that opt for sustainability and offers the possibility to compare different products, processes, and value chain scenarios, both real and hypothetical. Coupled with S-ROI (Sustainable Return on Investment), the LCA has a great potential in using available data for existing mining sites in the North-East Region of Romania to assess the economic, social and environmental benefits of certain sustainability measures on a local and regional level. The article will explore this approach of combining the two methodologies: LCA (Life Cycle Assessment) and S-ROI (Sustainable Return on Investment), with necessary adjustments according to the characteristics of the local mining activities, to show key investment areas that can improve the value chain of copper exploitation and preparation in the mining perimeter Mănăila. The case of the copper mine in Mănăila offers a great opportunity to apply the current LICYMIN (Life Cycle of Mining) research and to use available Ecoinvent data for the copper ore by comparing the current value chain scenario with a proposed scenario that includes a different location for a mining ore preparation unit, closer to the quarry. The results will give an insight into the potential social and economic impact (the measure can translate into a higher local employment rate, better social stability, lower transportation costs, etc.) as well as the environmental impact (reduction of GHG emission, pollution, and energy efficiency) of the suggested changes.

Combining iron and copper ores can generate an oxygen carrier that has a synergic effect of high temperature resistance and high reactivity. In this work, typical cements available in the market were studied as binders to bind magnetite and chalcopyrite to develop a suitable oxygen carrier for chemical-looping combustion (CLC). A first selection step suggested that an aluminate cement, namely CA70, could favor the generation of oxygen carrier particles having good crushing strength, good particle yield, and high reactivity. The CA70-bonded oxygen carrier was then subjected to cyclic tests with CH4, CO, and H2 in reduction and in air oxidation at temperatures of 850, 900, and 950 °C with gas concentrations of 5, 10, 15, and 20% in a batch-fluidized bed reactor. The increase in temperature promoted the fuel conversion. At 950 °C, the conversions of CH4 and CO reached up to 80.4% and 99.2%, respectively. During more than 30 cycles, the oxygen carrier kept a similar reactivity to the fresh carrier and maintained its composition and physical properties. The oxygen transport capacity was maintained at 21–23%, and the phases were CuO, Fe2O3, Al2O3, and minor CaS. In the used sample, some grains were observed, but the morphology was not greatly changed. Agglomeration was absent during all the cycles, except for the deep reduction with H2. [ABSTRACT FROM AUTHOR]

This paper describes the adopted approach for increasing the capacity of an existing industrial grinding circuit by adapting the respective configuration to process the ore from a new mine. Accordingly, due to Sossego mine exhaustion, Vale S. A. decided to use the existing industrial facilities and infrastructure for processing the Cristalino ore deposit located in Para state, within the Brazilian Amazon. Considering the higher hardness of Cristalino ore compared to Sossego ore, a reduction in capacity in the existing SAG grinding circuit was anticipated. A comprehensive grinding pilot plant campaign was conducted with a characterization program including 98 Cristalino ore samples, as described throughout this paper. Sossego grinding circuit was also surveyed for mathematical modeling and simulations to assess such an estimative further. The mathematical model calibration for setting different circuit configurations and operating conditions to enhance the circuit's capacity was based on the combination of pilot plant results and ore characterization. Simulations indicated that a capacity increase of 12% would be achieved in the existing grinding circuit by further crushing 35% of SAG mill fresh feed. Such figures would represent yearly additions of 8.3 kt in copper and 250 kg in gold productions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetite product with nearly 85 % of Fe 2 O 3 was extracted from Sinai copper ore. • Magnetite/heated glauconite mixture was activated to form a magnetic geopolymer (GMG) for crystal violet adsorption. • The Freundlich and multilayer models fitted the CRV uptake at all temperatures. • CRV adsorption capacities of this new material ranged from 612 to 684 mg/g. • GMG displayed high adsorption capacity (nearly 74%) after the fourth adsorption–desorption cycle. Sinai copper ore with 9.48 % of Fe 2 O 3 was treated using a laboratory-scale mineral processing techniques that included size reduction (below 75 µm) and a wet low intensity drum-type magnetic separation. After this treatment method, the separated magnetite product containing about 85 % of Fe 2 O 3 was extracted. A mixture of heated glauconite (900 °C/2h) and the extracted magnetite was activated by sodium silicate (Na 2 SiO 3) to obtain a novel glauconite-based magnetic geopolymer (namely GMG). Several analytical techniques (i.e., XRD, XRF, FESEM, FTIR, EDX, TEM, elemental mapping, and zeta potential) were used in the characterization of GMG and its performance for crystal violet (CRV) remediation was studied. The equilibrium data at pH 8.0 and 25 – 50 °C were fitted to a statistical physics multilayer model and classical isotherm equations to understand the CRV adsorption mechanism. The theoretical calculations indicated that GMG can adsorb 1.12 to 1.39 of CRV molecules per functional group (n), suggesting the presence of a multi-interaction mechanism and vertical adsorption orientation on GMG surface. For this basic dye, the estimated saturation adsorption capacities (Q sat) ranged from 684 to 612 mg/g, and an exothermic binding interaction was associated with the removal of this dye molecule. The adsorption energies (Δ E) ranged between 15.05 and 36.74 kJ/mol, indicating that physical forces, such as electrostatic interactions and hydrogen bonds, governed the GMG-CRV interactions. After fourth adsorption–desorption cycles, the regenerated GMG showed 74 % of its adsorption capacities, which suggested the suitability of this adsorbent to be regenerated and reused multiple times in water treatment. Overall, the combination between the separated magnetite and glauconite was an effective approach for the remediation of effluents that contain dye molecules [ABSTRACT FROM AUTHOR]

In recent years, studies have shown that bubble structure, which is affected by reagent types, dosages, and particle size, is closely related to flotation performance. In contrast to two-phase systems, there is very limited information regarding bubble size in three-phase systems. To this aim, we investigated the relationship between bubble size and flotation performance with two different copper ores. Firstly, the surface tension and bubble size measurements were carried out in two-phase systems with Methyl isobutyl carbinol, and Polypropylene glycol methyl ether. Then the bubble size measurements were performed in three-phase systems at laboratory and industrial scales. The results showed that surface tension decreased with higher frother amounts and higher pHs. Although remarkable decreases in bubble size were observed with increasing frother amount, a direct relationship between surface tension and bubble size was not observed. However, pH affected the behavior of the frother, resulting in smaller bubble sizes at pH 12 compared to pH 7. Similarly, the three-phase laboratory tests showed that higher amount of frother caused a reduction in the bubble size and the copper grade. Increasing the amount of collector also caused the bubble size and copper grade to decrease, but the frothers were more effective in bubble size reduction. Compared to the two-phase, in the three-phase study bubble size was notably bigger due to the presence of a collector and solid. In the plant scale, smaller bubble size and higher grade were obtained compared with the laboratory scale due to presence of cleaning circuit measurements. The froth phase properties were also affected by the ore types due to properties such as size and hydrophobicity of the various mineral species present. [Display omitted] [ABSTRACT FROM AUTHOR]

• The hydroforming method is developed for hundred-ton industrial granulation. • The resource utilization of natural materials and industrial wastes is realized. • An inexpensive composite oxygen carrier is prepared with negligible sintering. • Cu10.9Red89.1@C reaches 97 % of CH 4 conversion and 98 % of CO 2 selectivity. • The production cost of Cu10.9Red89.1@C is as low as $0.95/kg. The industrial granulation of low-cost and high-performance oxygen carriers (OCs) is critical to developing MW or larger-scale chemical looping combustion (CLC) demonstration units. In this work, an inexpensive composite OC, Cu10.9Red89.1@C (8.72 wt% copper ore and 71.28 wt% red mud bonded by 20 wt% cement), is innovatively prepared at a large scale by the hydroforming method. Its long-period performance is comprehensively evaluated in a thermogravimetric analyzer (TGA) and a batch fluidized bed, and TGA results show that Cu10.9Red89.1@C exhibits excellent stability and reactivity even in the case of deep reduction by H 2 in TGA. In addition, an obvious activation of Cu10.9Red89.1@C is observed during the CH 4 CLC test, indicated by the increased CH 4 conversion and CO 2 selectivity from 81.58 % and 74.65 % in the 1st cycle to 97.53 % and 98.24 % after activation, respectively. With Cu20Fe80@C (16 wt% copper ore and 64 wt% iron ore bonded by 20 wt% cement) as a reference, Cu10.9Red89.1@C presents a higher CH 4 conversion, CO 2 selectivity, and faster oxygen transfer rate due to its larger specific surface area and alkali metals in it. Finally, the cost analysis concludes that its production cost is only $0.95/kg for Cu10.9Red89.1@C, much cheaper than other large-scale prepared OCs. This work provides theoretical support for the applicability of the hydroforming method and the oxygen carrier Cu10.9Red89.1@C. [ABSTRACT FROM AUTHOR]

The global market has announced copper as a modern energy metal and finds its extensive utilization in the construction industry, electrical wiring, power transmission lines, alloying, anticorrosive coating, heat exchangers, refrigeration tubing, etc. Copper ore is primarily beneficiated from sulphide mineral deposits. Due to high-grade copper sulphide deposit exhaustion, the focus has now shifted towards recovery from different lean-grade oxide and mixed ore deposits. The present paper summarizes the utilization of copper as a clean energy mineral and its importance in the current renewable energy sector. Extensive research has been carried out on the flotation of copper sulphide ore as compared to copper oxide and mixed type ores. Besides flotation, other beneficiation techniques (selective flocculation and gravity separation) are also discussed in the present review. A few novel pretreatment methods are currently being studied for copper ore to intensify the separation for higher productivity. [ABSTRACT FROM AUTHOR]

This research work introduces a novel hybrid geometallurgical approach to develop a deep and comprehensive relationship between geological and mining characteristics with metallurgical parameters in a mineral processing plant. This technique involves statistically screening mineralogical and operational parameters using the Historical Data (HD) method. Further, it creates an intelligent bridge between effective parameters and metallurgical responses by the Deep Learning (DL) simulation method. In the HD method, the time and cost of common approaches in geometallurgical studies were minimized through the use of available archived data. Then, the generated DL-based predictive model was enabled to accurately forecast the process behavior in the mineral processing units. The efficiency of the proposed method for a copper ore sample was practically evaluated. For this purpose, six representative samples from different active mining zone were collected and used for flotation tests organized using a randomizing code. The experimental results were then statistically analyzed using HD method to assess the significance of mineralogical and operational parameters, including the proportions of effective minerals, particle size, collector and frother concentration, solid content and pH. Based on the HD analysis, the metallurgical responses including the copper grade and recovery, copper kinetics constant and iron grade in concentrate were modeled with an accuracy of about 90%. Next, the geometallurgical model of the process was developed using the long short-term memory neural network (LSTM) algorithm. The results showed that the studied metallurgical responses could be predicted with more than 95% accuracy. The results of this study showed that the hybrid geometallurgy approach can be used as a promising tool to achieve a reliable relationship between the mining and mineral processing sectors, and sustainable and predictable production. [ABSTRACT FROM AUTHOR]

Blasting and fracking of rock in mines exposes fresh rock surfaces to the local water and microbial communities. This may lead to leaching of metals from the rock by chemical or biological means and can cause acidification of the water system in the mine, i.e., acid rock drainage (ARD). Failure to prevent leakage of metal contaminated mine water may be harmful for the environment, especially to the local groundwater. In the Rudna mine, Poland, an in situ bioleaching pilot test at approximately 1 km depth was performed in the H2020 BIOMOre project (Grant Agreement #642456). After the leaching stage, different methods for irreversible inhibition of acidophilic iron oxidizing microorganisms used for reoxidation of reduced iron in the leaching solution were tested and were shown to be effective. However, the potential of the natural mine water microbial communities to cause leaching of copper or acidification of the mine waters has not been tested. In this study, we set up a microcosm experiment simulating the exposure of freshly fractionated Kupferschiefer sandstone or black schist to two different chloride-rich water types in the Rudna mine. The pH of the microcosms water was measured over time. At the end of an 18-week incubation, the bacterial community was examined by high throughput sequencing and qPCR, and the presence of copper tolerant heterotrophic bacteria was tested by cultivation. The dissolution of copper into the chloride rich microcosm water was measured. The pH in the microcosms did not decrease over the time of incubation. The sandstone increased the number of bacteria in the microcosms with one or over two orders of magnitude compared to the original water. The bacterial communities in the two tested mine waters were diverse and similar despite the difference in salinity. The bacterial diversity was high but changed in the less saline water during the incubation. There was a high content of sulphate reducing bacteria in the original mine waters and in the microcosms, and their number increased during the incubation. No acidophilic iron oxidizers were detected, but in the microcosms containing the less saline water low numbers of Cu tolerant bacteria were detected. Copper to a concentration of up to 939 mg L−1 was leached from the rock also in the microbe-free negative controls, which was up to 2.4 times that leached in the biotic microcosms, indicating that the leaching was also abiotic, not only caused by bacteria. [ABSTRACT FROM AUTHOR]

The paper includes the results of laboratory studies for the copper-bearing ore flotation with the use of a combined reagent. The combined flotation reagent was preliminarily passed through a UZDN-A1200T ultrasonic disperser before flotation to obtain a reagent microemulsion. The copper content in the concentrate was 21,5 % with extraction of 83,3 % in a closed cycle in the base mode. It was 21,8 % with an extraction of 88,3 % when a combined flotation reagent was used. There is an increase in copper extraction by 5 %. The combined reagent consumption is reduced by 15 % compared to the main technology.

The early rejection of gangue minerals, at coarse ore particles size (preconcentration), has been shown to be a viable option to cost reduction in many mineral processing applications. A promising technique being explored for efficient ore preconcentration is the Near InfraRed (NIR) spectroscopy. This paper attempts to validate the efficiency of near infrared preconcentration strategies, by comparing data of preconcentrated particles, when particles are scanned using near line scanner from different sides and angle of view. Three copper particles were selected from a batch of sixty preconcentrated samples, mineralogical and near infrared analysis were performed on the particles. Particles were then cut laterally (cross sectioned) and mineralogical and near infrared analysis repeated on the cut cross sectioned surface. Data of the whole samples and crosssectioned samples are compared. Results indicate that the depth attained by scanning (both with NIR and QEMSCANr) of original samples is representative of each sample scanned and sufficient for preconcentration. Also, except for the differences in particle size, correlation is almost 1:1, thus, validating the initial NIR preconcentration results as being promising. [ABSTRACT FROM AUTHOR]

A copper mine in Yunnan is located in the high altitude area. After comparison, the frother PL-1, which is mainly composed of imported raw materials, was used. In the first two years of production, the raw ore had simple properties and less mud content, and good production indexes had been achieved. With the deepening of mining, the mud content of ore increased, and the production index decreased greatly if the original frother was used continuously. In order to improve the production index and realize the domestic substitution of frother, the industrial application test of new special frother BK208 was carried out. After a period of industrial test comparison, the accumulative total index of industrial test with original frother PL-1 was as follows: copper concentrate containing Cu grade of 23.93%, Cu recovery of 84.67% .The accumulative index of the frother BK208 was that copper concentrate contains 22.67% Cu with the recovery of 86.50%. The copper recovery using BK208 is 1.83 percentage points higher than that of using PL-1. It is estimated that the annual economic benefit will exceed 68 million yuan. [ABSTRACT FROM AUTHOR]

The copper content of a low-grade sulfur-oxygen mixed copper ore in Yunnan is 1.03%, which is the main valuable metal. Among them, copper sulfide accounts for 71.67%, copper oxide accounts for 28.33%, silicon dioxide and calcium oxide accounts for 43.26% and 12.66% respectively. Silicate and carbonate are the main gangue minerals. Through systematic experimental study, the asynchronous flotation-staged sulfurization process was determined, in which copper sulfide was selected first and then copper oxide was selected. Butyl xanthate was used as collector and lime as cleaning depressant in the flotation of copper sulfide, and butyl xanthate + ammonium dibutyl dithiophosphate was used as collector, sodium sulfide as vulcanizing agent and CMC as cleaning depressant in the flotation of copper oxide. In the two stages of roughing operation, depressant is not added to ensure copper recovery, while in the cleaning operation, depressant is added to improve copper grade. Finally, copper sulfide concentrate with copper grade of 18.95% and copper recovery of 66.27%, and copper oxide concentrate with copper grade of 20.11% and copper recovery of 19.87% can be obtained and the total copper recovery is 86.14%. [ABSTRACT FROM AUTHOR]

This paper presents the results of an industrial testing of the phase of rough flotation of copper ore from the deposit "North revir" in the Copper Mine Majdanpek. The achieved technological parameters in the rough flotation process, the results of grain size analysis by size classes of on the tested products, as well as the recovery and content of copper by size classes in the products of rough flotation show that the process of rough flotation does not work satisfactorily.

The early rejection of gangue minerals, at coarse ore particles size (preconcentration), has been shown to be a viable option to cost reduction in many mineral processing applications. A promising technique being explored for efficient ore preconcentration is the Near InfraRed (NIR) spectroscopy. This paper attempts to validate the efficiency of near infrared preconcentration strategies, by comparing data of preconcentrated particles, when particles are scanned using near line scanner from different sides and angle of view. Three copper particles were selected from a batch of sixty preconcentrated samples, mineralogical and near infrared analysis were performed on the particles. Particles were then cut laterally (cross sectioned) and mineralogical and near infrared analysis repeated on the cut cross sectioned surface. Data of the whole samples and cross-sectioned samples are compared. Results indicate that the depth attained by scanning (both with NIR and QEMSCAN(R) of original samples is representative of each sample scanned and sufficient for preconcentration. Also, except for the differences in particle size, correlation is almost 1:1, thus, validating the initial NIR preconcentration results as being promising.

Since the start-up of the Sossego copper concentrator, located in the Carajás Mineral Province in the southeast of Para State, Brazil, the low-grade ore (~0.34% Cu) has been stockpiled, as defined in the long-term mine plan, to be reclaimed at the end of the mine life. Given this imminent need to process around 40 Mt of this low-grade ore, questions have been raised related to the extent of oxidation that might have occurred in this stockpiled ore. In this context, a study was designed to characterize the stockpiled ore and assess the effect of the ore oxidation on its flotation response. A sampling campaign of the stockpiled ore was carried out to analyze the main variables that could influence the level of oxidation, and, consequently, copper recovery, such as stockpiling time, depth, and particle size. The results showed that there are two main factors negatively impacting the copper recovery of the low-grade stockpiled ore: the surface oxidation and the level of liberation of the copper mineral. Depth and period of stockpiling were not found to influence the level of oxidation, nor the flotation response. An empirical model was proposed for the copper recovery in the rougher stage, which resulted in a predicted value of 90.7%, which was lower than that for the fresh (and higher copper content) ore fed to the plant (93%).

The moisture of bulk material has a significant impact on the energetic efficiency of dry grinding, resultant particle size distribution and particle shape, and conditions of powder transport. This research aims to develop computer vision and thermovision techniques for the on-site estimation of moisture content in copper ore, for use, e.g., in dry grinding installations. The influence of particle size on the results of moisture estimation is also studied. The tested granular material was copper ore of particle size 0–2 mm and relative moisture content of 0.5–11%. Both vision and thermovision images were taken at standard and macro scales. The results suggest that median-intensity vision images monotonically reflect copper ore moisture in the range of about 0.5–5%. Suitable models were identified and cross-validated here. In contrary, thermograms should not be analyzed simply for their mean temperature but treated with computer vision processing algorithms.

The verification efficiency and precision of copper ore grade has a great influence on copper ore mining. At present, the common method for the exploration of reserves often uses chemical analysis and identification, which have high costs, long cycles, and pollution risks but cannot realize the in situ determination of the copper grade. The existing scalar spectrometric techniques generally have limited accuracy. As a vector spectrum, polarization state information is sensitive to mineral particle distribution and composition, which is conducive to high-precision detection. Taking the visible-near infrared parallel polarization reflectance spectrum data and grade data of a copper mine in Xiaoyuan village, Huaining County, Anhui Province, China, as an example, the characteristics of the parallel polarization spectra of the copper mine were analyzed. The spectra were pretreated by first-order derivative transform and wavelet denoising, and the dimensions of wavelet denoising spectra, parallel polarization spectra, and first-order derivative spectra were also reduced by principal component analysis (PCA). Three, four, and eight principal components of the three types of spectra were selected as variables. Four machine learning models, the radial basis function (RBF), support vector machine (SVM), generalized regression neural network (GRNN), and partial least squares regression (PLSR), were selected to establish the PCA parallel polarization reflectance spectrum and copper grade prediction model. The accuracy of the model was evaluated by the determination coefficient (R2) and root mean square error (RMSE). The results show that, for parallel polarization spectra, first-order derivative spectra, and wavelet denoising spectra, the PCA-SVM model has better results, with R2 values of 0.911, 0.942, and 0.953 and RMSE values of 0.022, 0.019, and 0.017, respectively. This method can effectively reduce the redundancy of polarized hyperspectral data, has better model prediction ability, and provides a useful exploration for the grade analysis of hydrothermal copper deposits at meso-low temperatures.

The paper includes the results of laboratory studies for the copper-bearing ore flotation with the use of a combined reagent. The combined flotation reagent was preliminarily passed through a UZDN-A1200T ultrasonic disperser before flotation to obtain a reagent microemulsion. The copper content in the concentrate was 21,5 % with extraction of 83,3 % in a closed cycle in the base mode. It was 21,8 % with an extraction of 88,3 % when a combined flotation reagent was used. There is an increase in copper extraction by 5 %. The combined reagent consumption is reduced by 15 % compared to the main technology. [ABSTRACT FROM AUTHOR]

LCA (Life Cycle Assessment) is a useful tool in decision-making for most businesses that opt for sustainability and offers the possibility to compare different products, processes, and value chain scenarios, both real and hypothetical. Coupled with S-ROI (Sustainable Return on Investment), the LCA has a great potential in using available data for existing mining sites in the North-East Region of Romania to assess the economic, social and environmental benefits of certain sustainability measures on a local and regional level. The article will explore this approach of combining the two methodologies: LCA (Life Cycle Assessment) and S-ROI (Sustainable Return on Investment), with necessary adjustments according to the characteristics of the local mining activities, to show key investment areas that can improve the value chain of copper exploitation and preparation in the mining perimeter Mănăila. The case of the copper mine in Mănăila offers a great opportunity to apply the current LICYMIN (Life Cycle of Mining) research and to use available Ecoinvent data for the copper ore by comparing the current value chain scenario with a proposed scenario that includes a different location for a mining ore preparation unit, closer to the quarry. The results will give an insight into the potential social and economic impact (the measure can translate into a higher local employment rate, better social stability, lower transportation costs, etc.) as well as the environmental impact (reduction of GHG emission, pollution, and energy efficiency) of the suggested changes. [ABSTRACT FROM AUTHOR]

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