Search

High concentrations of harmful metal(loid)s and extreme acidity are persistent environmental concerns in acidic pit lakes. In this study, we examine Cueva de la Mora (CM), a meromictic pit lake in the Iberian Pyrite Belt, Spain, as a model system. Our research aims to explore potential bioremediation strategies to mitigate the impacts of metal(loid)s and acidity in such environments. The major strategy applied in this research is to biologically stimulate sulfate reduction (i.e., biosulfidogenesis) in the deep layer of the lake to promote the formation of low-solubility sulfide minerals. Previous omics-based studies of CM have shown that several sulfate-reducing bacteria (SRB) taxa are present in the deep layer. However, their activities are likely limited by the availability of electron donors for sulfide production. Therefore, different amendments (glycerol, elemental sulfur, and glycerol + elemental sulfur) were tested to promote sulfide production and enrich acid-tolerant sulfide-producing microbes. Our results showed that glycerol stimulated dissimilatory sulfate reduction much faster than elemental sulfur alone, suggesting that electron donor limitations control sulfide production. Furthermore, the combined addition of glycerol and elemental sulfur (S(0)) resulted in the highest level of sulfide production. This indicates that S(0) can play a significant role as an electron acceptor in further promoting sulfide production when a suitable electron donor is present. Microbial community analysis revealed that Desulfosporosinus acididurans , a previously discovered acid-tolerant SRB, was enriched and became the dominant species in incubations with glycerol only (~76–96% abundance) or the combination of glycerol and S(0) (~93–99% abundance). [ABSTRACT FROM AUTHOR]

Mine environments in boreal and sub-boreal zones are expected to experience extreme weather events, increases in temperature, and shifts in precipitation patterns. Climate change impacts on geochemical stability of tailings contaminants and reclamation structures have been identified as important climate-related challenges to Canadian mining sector. Adapting current reclamation strategies for climate change will improve long-term efficiency and viability of mine tailings remediation/restoration strategies under a changing climate. Accordingly, mesocosm experiments were conducted to investigate associations of climate-driven shifts in microbial communities and functions with changes in the geochemistry of organic covers and underlying tailings. Our results show that warming appears to significantly reduce C:N of organic cover and promote infiltration of nitrogen into deeper, unoxidized strata of underlying tailings. We also observed an increase in the abundance of some nitrate reducers and sulfide oxidizers in microbial communities in underlying tailings. These results raise the concern that warming might trigger oxidation of sulfide minerals (linked to nitrate reduction) in deeper unoxidized strata where the oxygen has been eliminated. Therefore, it would be necessary to have monitoring programs to track functionality of covers in response to climate change conditions. These findings have implications for development of climate resilient mine tailings remediation/restoration strategies. [ABSTRACT FROM AUTHOR]

The article discusses the discovery and mineralogy of greenlizardite, a hydrated ammonium sodium uranyl sulfate found in the Green Lizard mine in San Juan County, Utah. The mineral formed in a secondary crust on a mined wall underground and is associated with other sulfate minerals. The history of mining in the White Canyon district, particularly the uranium boom during World War II and the subsequent decline in production, is also detailed. The Green Lizard mine, now closed with a bat-accessible grate, has been the site of mineral collection and research, leading to the discovery of new minerals. [Extracted from the article]

Granite-related W-Sn ore systems are commonly associated with coeval Pb-Zn mineralization. It remains unclear whether these metals are derived from the same sources or not. Mercury (Hg) is a common minor component in such systems. Hg isotopes undergo unique mass-independent fractionation (expressed as Δ199Hg values), which is mainly generated during Hg photochemical reactions on Earth's surface and not affected by magmatic-hydrothermal processes, offering an excellent opportunity to trace metal sources in hydrothermal systems. We observed near-zero Δ199Hg values in wolframite (−0.10‰ to 0.08‰, n=11), and in skarn- (−0.17‰ to 0.12‰, n=48) and greisen-type (−0.12‰ to 0.10‰, n=11) bulk tin-tungsten ore from eight major ore deposits in South China. These values are identical to those of coeval highly evolved granites (−0.13‰ to 0.12‰, n=49), supporting that Hg in W-Sn ores were sourced from granite. However, sulfides (e.g., pyrite, chalcopyrite, arsenopyrite, galena, and sphalerite) in these deposits exhibit negative to near-zero Δ199Hg values (−0.42‰ to 0.09‰, n=124), which indicates a contribution of Hg and by inference other metals from both Precambrian basement rocks (Δ199Hg<0) and ore-related granites. The study demonstrates that multiple sources of metals were involved in the formation of the polymetallic W-Sn deposits, and further highlights that extraction of metals from basement rocks may be a critical control on the formation of economically important mineralization of base metal sulfides (e.g., Pb, Zn) in granite-related magmatic-hydrothermal systems. [ABSTRACT FROM AUTHOR]

Complex gold-iridium-osmium placer deposits associated with the Guli massif of ultramafic, alkaline rocks and carbonatites are located within the Maimecha-Kotui province in the northern part of the Siberian Platform. Unlike natural Os-Ir alloys, which are genetically related to ultramafic rocks, the bedrock source of gold remains controversial. We report, for the first time, morphological and compositional features of gold mineralization from calcite-dolomite carbonatite of the Guli massif. Gold minerals are represented by natural Au-Ag alloys containing gold (69.64–88.57 wt %) and silver (11.73–30.83 wt %) with low concentrations of copper (up to 0.18 wt %), which predominate over minerals of the system Au–Cu–Ag (e.g., natural alloys Au0.74Cu0.14Ag0.12 and Ag0.51Au0.47Cu0.02, tetra-auricupride (AuCu) and auricupride (Cu3Au)). Gold minerals are characterized by an early pentlandite-troilite-chalcopyrite association that form polyphase euhedral inclusions. Later galena (PbS) occurring in the form of subhedral monophase inclusions is replaced by cerussite (PbCO3). The revealed similarity of gold minerals and mineral assemblages in gold from calcite-dolomite carbonatite with those of gold minerals from placer deposits of the Guli massif indicates that derivatives of ijolite-carbonatite magmatism played a significant role in gold ore formation. [ABSTRACT FROM AUTHOR]

Oxidative weathering of sulfide minerals in sedimentary rocks releases carbon dioxide (CO2) into the atmosphere. In permafrost zones, this could be a positive feedback on climate change if it increases with warming, yet sulfide oxidation rates and their temperature response remain unknown over large spatial and temporal scales. We analyze a 60-year sulfate concentration dataset from catchments across the Mackenzie River Basin. Sulfate fluxes increased by 45% in the mainstem with 2.3°C of warming, and the temperature sensitivity suggests that continental-scale CO2 fluxes could double by 2100. The largest increases occur in catchments with geomorphic settings which act to rapidly expose rocks through physical weathering and thermokarst processes. Comparisons with a weathering model suggest that warming can increase reaction rates, and changes in the exposure of minerals with warming are also required. Future warming across vast Arctic landscapes could further increase sulfide oxidation rates and affect regional carbon cycle budgets. [ABSTRACT FROM AUTHOR]

Considering the urgency of resource utilization and environmental protection, the geochemistry of anomalous trace transition metal elements in coal formed in terrestrial environments has been studied using methods such as inductively coupled plasma atomic emission spectrometry analysis, electron probe micro-area analysis, sequential chemical extraction procedures, and correlation analysis. The results indicate that minerals in the coal samples included pyrite, kaolinite, quartz, dolomite, calcite, and celestite. Furthermore, compared with the average values of coals in China and the upper continental crust, the coal samples were rich in transition metal trace elements such as Ni, Cr, and Sr and were deficient in Be, Cd, Cu, Co, Ga, Mo, Sb, Tl, V, Zn, and Ti. We found that Ni preferentially occurred in the organic matter over minerals, while Cr primarily bonded with sulfide minerals and to a lesser extent with the iron-manganese oxide minerals. Sr had a low correlation with organic matter but adhered to clay minerals and celestite. Ni enrichment in coal samples was the result of terrigenous input, while the Cr enrichment was related to intrusion of magmatic hydrothermal fluids. Sr enrichment was caused by the presence of SO42- in the terrigenous debris and the influence of Sr-rich water underground. [ABSTRACT FROM AUTHOR]

The Chazangcuo copper-lead-zinc deposit (hereafter referred to as the Chazangcuo deposit) is situated in the northern portion of the western section of the Gangdese polymetallic metallogenic belt in Tibet, with ore bodies strictly governed by Linzizong Group magmatic rocks and EW-trending faults. This study aims to ascertain the mineralization periods, sources of oreforming materials, metallogenic physicochemical conditions, and genesis of this deposit. Based on comprehensive field geological surveys, sampling, and microscopic examination of petrological and mineralogical characteristics, we perform qualitative and quantitative geochemical analyses of major elements, trace elements, and rare earth elements (REEs), fluid inclusions, and sulfur and lead isotopes. The findings reveal that the mineralization process of the Chazangcuo deposit can be divided into three periods and four stages: the magmatic-hydrothermal, hydrothermal, and supergene mineralization periods sequentially, which consist of the mineralization stages of quartz-pyritesphalerite, medium-low-temperature hydrothermal sulfides, chlorite-carbonate minerals, and supergene oxidation in a chronological order. The ore-forming fluids prove to be medium-low-temperature low-density fluids, and the oreforming materials are characteristic of upper crustal-derived materials. The ore-forming environment is a medium-low mineralization temperature, a shallow and weakly reducing environment. Overall, the Chazangcuo deposit is identified as a medium-low-temperature magmatic-hydrothermal deposit. The metallogenic model has the vertical zoning characteristics of lead-zinc in the upper part and copper in the lower part. [ABSTRACT FROM AUTHOR]

Against the backdrop of the increasing copper demand in a low-carbon economy, this work statistically forecasted the distribution of China's copper tailings for the first time, and then characterized them as finely crushed and low-grade mining solid wastes containing copper mainly in the form of chalcopyrite, bornite, covelline, enargite and chalcocite based on available research data. China is the globally leading refined copper producer and consumer, where the typical commercial-scale bioleaching of copper tailings is conducted in the Dexing, Zijinshan and Jinchuan mining regions. And these leaching processes were compared in this study. Widely used chemolithoautotrophic and mesophilic bacteria are Acidithiobacillus, Leptospirillum, Acidiphilium, Alicyclobacillus and Thiobacillus with varied metal resistance. They can be used to treat copper sulfide tailings such as pyrite, chalcopyrite, enargite, chalcocite, bornite and covellite under sufficient dissolved oxygen from 1.5 to 4.1 mg/L and pH values ranging from 0.5 to 7.2. Moderate thermophiles (Acidithiobacillus caldus, Acidimicrobium, Acidiplasma, Ferroplasma and Sulfobacillus) and extreme thermophilic archaea (Acidianus, Metallosphaera, Sulfurococcus and Sulfolobus) are dominant in leaching systems with operating temperatures higher than 40 °C. However, these species are vulnerable to high pulp density and heavy metals. Heterotrophic Acidiphilium multivorum, Ferrimicrobium, Thermoplasma and fungi use organic carbon as energy to treat copper oxides (malachite, chrysocolla and azurite) and weathered sulfides (bornite, chalcocite, digenite and covellite) under a wide pH range and high pulp density. We also compared autotrophs in a planktonic state or biofilm to treat different metal sulfides using various sulfur-cycling enzymes involved in the polysulfide or thiosulfate pathways against fungi that produce various organic acids to chelate copper from oxides. Finally, we recommended a bioinformatic analysis of functional genes involved in Fe/S oxidization and C/N metabolism, as well as advanced representation that can create new possibilities for the development of high-efficiency leaching microorganisms and insight into the mechanisms of bioleaching desired metals from complex and low-grade copper tailings. [ABSTRACT FROM AUTHOR]

Copper sulfide ores frequently co-occur with pyrite, presenting a significant challenge for their selective separation during beneficiation processes. Despite advancements in flotation technology, there remains a critical need for efficient methods to enhance copper recovery while suppressing pyrite interference, particularly without compromising the associated precious metals such as gold and silver. Current practices often struggle with achieving high selectivity and recovery while maintaining environmental sustainability. Here, we investigate the efficacy of a ternary collector mixture consisting of ammonium dibutyl dithiophosphate (ADD), butyl xanthate (BX), and ethyl xanthate (EX) for the selective flotation of copper sulfide from a complex ore containing 0.79% Cu and associated precious metals (0.233 g/t Au and 5.83 g/t Ag). A combination of lime and hydrogen peroxide as inhibitors was employed to suppress pyrite effectively under alkaline conditions (pH = 11.33). The results demonstrate that the optimized ternary collector system (ADD:BX:EX at a ratio of 1:0.5:0.5) significantly improves the copper grade and recovery at an ultra-low dosage of 10 g/t. The optimized flotation method using the combined collectors and inhibitors effectively separated chalcopyrite from pyrite, achieving a copper concentrate with 20.08% Cu content and a recovery of 87.73%. Additionally, the process yielded notable recoveries of gold (9.22%) and silver (26.66%). These findings advance the field by providing a viable and environmentally conscious approach to the beneficiation of sulfide ores, potentially serving as a blueprint for processing similar mineral deposits while minimizing reagent usage and costs. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to determine the order of the paragenetic sequence and phase transitions of the Ni–Fe sulfide association hosted in listvenites. Listvenites are hydrothermally altered mafic and ultramafic rocks that are often associated with active tectonic settings, such as transform faults, suture zones, and regional extensional faults, usually in contact with volcanic or carbonate rocks. Listvenitization is displayed by a carbonation process when the original olivine, pyroxene, and serpentine group minerals are altered to Mg–Fe–Ca carbonates (magnesite, calcite, dolomite, and siderite), talc, quartz, and accessory Cr spinel, fuchsite, and Ni–Fe sulfides. The formed rocks are highly reactive; therefore, very often, younger hydrothermal processes are observed, overprinting the mineralogy and geochemistry of the original listvenitization products, including accessory Ni–Fe sulfide paragenesis. The studied samples of listvenites were collected from two locations in Kosovo (Vardar Zone): Janjevo and Melenica. The Ni–Fe sulfide textures and relationships with the surrounding listvenite-hosted minerals were obtained using reflected and transmitted light microscopy, while their chemical composition was determined using an electron microprobe. They form accessory mono-or polymetallic aggregates that usually do not exceed 100 μm in size disseminated in the studied listvenites. Generally, the paragenetic sequence of Ni–Fe sulfides is divided into three stages. The first pre-listvenite magmatic phase is represented by pentlandite and millerite. The second listvenite stage consists of Ni–Co bearing pyrite I (Ni content up to 11.57 wt.% [0.24 apfu], and Co content up to 6.54 wt.% [0.14 apfu]) and differentiated thiospinels (violarite + siegenite ± polydymite). The last, late listvenite stage is represented by younger gersdorffite−ullmannite and base metal mineralization: pyrite + marcasite + sphalerite + galena ± chalcopyrite ± sulfosalts. The findings obtained should help in the interpretation of many disseminated accessory Ni–Fe–Co mineralizations associated with mafic and ultramafic rocks worldwide. [ABSTRACT FROM AUTHOR]

Mining in the Russian Far East has been developing for more than 100 years, resulting in the formation of mining technogenic systems that negatively affect all components of the environment. The purpose of this paper is to develop and present an ecological and geochemical model of supergene processes in tinsulfide and polymetallic ore mining systems. This paper presents, for the first time, the results of long-term field observations (more than 50 years): studies of numerous secondary minerals (more than 80) identified in mine workings and tailings, their natural associations, as well as the sequence, zonality, and stages of mineral formation as well as the characteristics of hydrochemical samples of river waters, contaminated by acid mine drainage (30 years of observations). Experimental modeling of sulfide oxidation was carried out under laboratory conditions (electrochemical method) and using Selektor software, which made it possible to study the process of acid mine drainage formation and to show the metal ions and ionic complexes composition, to establish Eh-pH parameters of crystallization for 52 secondary minerals, associations of primary and secondary minerals. The influence of water components on the formation of slurry and drainage in different time periods (dry, heavy rainfall, and snowmelt) is shown, and their mixing at the geochemical barrier "acid mine drainage—surface natural waters" is described. Experimental results are verified with numerous in-situ observations and mineralogical studies. The work allowed for the presentation of an environmental–geochemical model of ecosphere pollution, which describes not only the negative impact of sulfide-bearing systems of Russian Far East mining districts but locations all over the world. [ABSTRACT FROM AUTHOR]

The mafic-ultramafic intrusion in the XV anomaly area, contains magmatic Fe-Ti ox-ides±(p) ore, is located in the Bafq mining district in the Central Iran. It consists of cumulate and layered Fe-Ti-bearing gabbros and pyroxenites. The mineral assemblages include clinopyroxene, Fe-Ti oxides, plagioclase, amphibole, apatite and sulfides (pyrite and chalcopyrite). The Fe-Ti oxides mainly consist of magnetite-titanomagnetite and ilmenite, which occurred as disseminated, intergrowth, lamellae (trellis and sandwich textures) and inclusions. Magnetite in the gabbroic rocks is from the near end-member of Fe3O4 (<1 wt.% TiO2) to titanomagnetite containing up to 8 wt.% TiO2 (about 3.73 wt.% to 26.84 wt.% Ulvospinel (XUsp)). Magnetite in pyroxenite rocks is characterized with TiO2 range from 0.46 wt.% to 3.14 wt.% (XUsp varied from 1.76 wt.% to 10.46 wt.%). The abundances of V2O3 range from 0.03 wt.% to 1.29 wt.% and 0.24 wt.% to 1.00 wt.% for gabbro and pyroxenite, respectively. XUsp contents of magnetite show insignificant correlations with Al2O3 and MgO. The average XIlm in the ilmenite of gabbro is 92%, whereas it is 90.37% in the pyroxenite rocks. The MgO and V2O3 contents show a slightly positive correlation with TiO2 in ilmenite. The composition of clinopy-roxenes in gabbro and pyroxenite rocks fall in the diopside to augite field with Mg# ranging from 67 to 98 and 74 to 96, respectively. In both rock types, amphiboles are mainly pargasite and rarely actin-olite. Plagioclase in pyroxenite rocks is clustered in the labradorite to andesine fields with a compositional ranges of An46–69 and in gabboic rocks fall in two fields with compositional ranges of albite with An0.65–5.95 and labradorite with An50–63. The δ 34S isotopic values cover a limited range from +3.15‰ to +4.10‰ V-CDT consistent with magmatic origin. Fe-Ti mineralization is formed in two stages, minor inclusions of Fe-Ti oxide minerals in the pyroxene and plagioclase crystallized in the early magmatic stage, whereas interstitial oxides formed by fractional crystallization processes that accumulated by gravitational settling in the later stage as intercumulus phase. Gravitational settling process is supported by the observation of decreasing the amount of Fe-Ti oxides from Fe-Ti oxide-rich pyroxenite to weak mineralized gabbro (base to top). The high contents of H2O, phosphorate and high initial Ti-Fe in parental magma are the crucial factors controlling the Fe-Ti oxides enrichment and mineralization. [ABSTRACT FROM AUTHOR]

Accurately determining the timing of hydrothermal mineralization for sediment-hosted disseminated gold (SHDG) deposits is difficult because of a lack of both suitable chronometers and in situ techniques with the required spatial resolution and precision. The lack of precise age determinations on gold deposits has hindered understanding of their genesis and relation to the geodynamic setting. The Qiuling-Jinlongshan deposit is a typical SHDG deposit located in the eastern South Qinling Orogen (SQO), with 109 t Au at an average grade of 6.17 g/t. Devonian and Carboniferous metasedimentary rocks host structurally controlled gold mineralization, which is associated with silica-carbonate alteration. Pyrite, arsenopyrite, and arsenian pyrite are major gold carriers, and gold also occurs as native gold grains and invisible gold in the sulfides. In this study, the well-defined hydrothermal overgrowth rims (~2 μm) of single monazite grains, associated with disseminated auriferous arsenian pyrite and arsenopyrite in low-grade metasedimentary rocks, yield U-Pb ages of239 ± 13 Ma (2σ) by high spatial resolution secondary ion mass spectrometry (SIMS). The hydrothermal monazites are cogenetic to the primary gold mineralization where they are closely associated with gold-bearing sulfides. This new age implies that the early to middle Triassic mineralization event in the eastern SQO was related to the Triassic tectonic transition from compression to transpression in the Qinling Orogen after the closure of the Mianlue Ocean. This study highlights the 2-μm high spatial resolution SIMS monazite U-Th-Pb dating method as a powerful tool for determining the timing of SHDG deposits worldwide. It is crucial to examine monazite textures and their link to hydrothermal alteration before carrying out the isotopic dating of monazite. [ABSTRACT FROM AUTHOR]

The flotation characteristics of chalcopyrite, galena and sphalerite in the system with dextrin, sodium humate (HA-Na), cationic guar gum (CGG) and DP115 (modified polyacrylamide) as inhibitors and Z-200 as collector were investigated. The results showed that compared with the traditional system of adding macromolecular organic inhibitor first and then adding Z-200 collector, the three sulfide minerals showed different flotation behaviors in the system of adding Z-200 first and then adding macromolecular organic inhibitor. Chalcopyrite was basically not affected by dextrin, while dextrin more strongly inhibits galena, sphalerite was slightly activated by lower dosage of dextrin and was equivalent to that of adding dextrin first and then adding Z-200, and higher dosage of dextrin slightly enhanced the inhibition of sphalerite. HA-Na weakened the inhibition of three sulfide minerals. The inhibition of CGG on sphalerite, especially chalcopyrite, was enhanced, while the inhibition of galena was basically equivalent to that of CGG when added first. Chalcopyrite was basically not affected by DP115, and the lower amount of DP115 more strongly inhibited galena and sphalerite, while the inhibition of higher amount of DP115 on galena and sphalerite was basically the same as that of adding DP115 first and then Z-200. The research results can provide reference for the selection of organic macromolecular inhibitors and the improvement of flotation separation efficiency when Z-200 was used as collector in the flotation separation of copper-lead-zinc sulfide ore. [ABSTRACT FROM AUTHOR]

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]

The main metals contents in a platinum group polymetallic ore in South Africa are Pt 1.923 g/t, Pd 0.986 g/t, Au 0.276 g/t, Rh 0.113 g/t, Ru 0.316 g/t, Ir 0.047 g/t, Cu 0.071% and Ni 0.180%. The content of Cr2O3 is only 0.58%, and the contents of main gangue components SiO2, MgO, Al2O3 and CaO are 52.59%, 22.4%, 5.06% and 4.27% respectively. The total sulfide content in the ore is 0.94%, presenting mainly in pyrrhotite, nickelpyrite, chalcopyrite, followed by pyrite, trace chalcocite, sphalerite, and so on. The total amount of silicate minerals is 97.91% mainly bronze- pyroxene, followed by secondary diopside, a small amount of plagioclase, plagiozossite, quadrigalite, phlogopite, chlorite, and so on. Platinum group metals are mainly found in sulfide platinite, arsenic platinite, natural platinum, sulfide nickel palladium platinite, natural gold, silver gold and other minerals, while copper and nickel metals are mainly found in chalcopyrite and nickel pyrite. Under the condition of grinding tineness of -74 µm accounting for 55% the liberation degree of PPD rhodium minerals is 96.6% the proportion of exposed gold and sulfide wrapped gold are 69.21% and 20.67% respectively. In order to comprehensively recover the platinum group metal and valuable elements such as copper and nickel, beneficiation experiments were carried out. The results showed that under the process of "one roughing, two scavengings and three cleanings", with sodium carbonate, CMC and copper sulfate as regulators, amyl xanthoxanthate as collector, and terpineol oil as frother, the concentrate obtained contained Pt 57.562 g/t, Pd 34.836 g/t, Au 5. 201 g/t, Rh 3. 266 g/t, Cu 2.270% and Ni 3.830%. The metal recoveries were Pt 90.57%, Pb 93.80%, Au 51.63%, Rh 88.13%, Cu 87.03% and Ni 63.16%. The main impurities in the concentrate were SiO2 42.28%, MgO 19.82%, Al2O3 1.68%, CaO 1.89% and Fe 18.79% respectively. This study can provide technical reference for the exploitation and utilization of similar mineral resources. [ABSTRACT FROM AUTHOR]

With the gradual reduction of easily beneficiated copper sulfide ore resources, the recovery and utilization of refractory copper oxide ore has become an important research direction in the field of mineral processing. The grade of copper and gold in a gold-copper ore is 1.86% and 3.52 g/t, respectively. The particle size of independent gold minerals in the ore is mine, basically below 1 µm, or wrapped in metal mineral or gangue minerals in the form of line particles, and the oxidation rate of copper in the ore is 91.85%, so the ore belongs to refractory ore. In order to recover the valuable components in the ore to the greatest extent, different flotation product schemes are compared according to the ore properties, and the segmented Rotation process is determined to recover gold and copper in the ore, that is, copper sulfide minerals and gold-bearing sulfide minerals are preferentially floated from the ore to obtain qualified gold-copper concentrate. Copper oxide minerals are recovered from the tailings of selective flotation, and a copper concentrate product wkh gold valuation is obtained, thus the valuable components in the ore are recovered and utilized by a segmented flotation process. On the basis of detailed flotation condition tests, a small locked-cycle test was carried out, and finally a gold-copper concentrate with 15.39% Cu and 152.39 g/t Au and copper concentrate wkh 28.02% Cu and 10.39 g/t Au were obtained. Overall, the total concentrate had copper grade of 24.73% and gold grade of 47.41 g/t, wkh the total recovery of copper being 87.41% and the total recovery of gold being 88.32%. [ABSTRACT FROM AUTHOR]

Aiming at the problems of cassiterite overgrinding and sulfide minerals undergrinding in the grinding process of cassiterite polymetallic sulfide ore, this paper investigated the influence of grinding time, mill filling rate and other factors on the particle size distribution of grinding products and the efficiency of grinding technology based on the conditions of different grinding media. The results show that grinding times positively correlated with the yield of qualified and overgrinding particles in the grinding products, and negatively correlated with the yield of undergrinding particles, and the content of Φ20 mm steel balls in the combination of steel bals in the grinding media has a greater impact on the qualified and overgrinding particles, and has a smaller impact on the undergrinding particles. Grinding time has a greater impact on the efficiency of grinding technology, when the grinding times certain the higher the content of Φ20 mm steel balls in the media combination, the higher the efficiency of grinding technology. Mill filling rate and grinding products in the qualified particle yields positively correlated but the impacts less than the grinding time, grinding media ball combination of Φ20 mm steel ball content has a greater impact on this law whereas the impact of filling rate on yields of over-grinding and under-grinding particles is small. Mill filling rate has a certain effect on the efficiency of grinding technology, when the mill filling rates certain the higher the content of Φ20 mm steel bals in the media combination the higher the efficiency of grinding technology. The results of the study can provide reference for the optimization of grinding media in cassiterite polymetallic sulfide ore filling production and mitigation of cassiterite overgrinding and sulfide ore undergrinding. [ABSTRACT FROM AUTHOR]

China is rich in zinc ore resource, but the depletion of easily floatable sulfide zinc deposits has made the development and utilization of difficult-to-float oxidized zinc ores a pressing issue. Due to the high oxidation rate, complex mineral composition and structure, and high fine-mud content of oxidized zinc ore, Rotation faces significant challenge, including high processing costs and low resource utilization efficiency. This paper systematically reviews the research progress on the notation processes and reagents for oxidized zinc ore, analyzing the applicability and limitations of various notation methods, such as sulfide amine notation, sulfide xanthate notation, fatty acid notation chelation notation, and nocculation notation. Additionally, the paper introduces advancements in novel notation technique, such as staged notation, high-entropy activation notation, and dehydration notation, and discusses the mechanism and application status of collector, sulfurizer, activator, depressant, and nocculants developed domestically and internationally in recent years. Future developments in oxidized zinc ore notation technology will focus primarily on two areas: firstly, overcoming the limitations of existing techniques through innovative notation processes to enhance recoveries and processing efficiency, and secondly, deepening research on highly efficient notation reagent, particularly the optimization of selective collector, activator, depressant, and occulant, to further reduce notation costs and improve the development and utilization of oxidized zinc ore resources. [ABSTRACT FROM AUTHOR]

Tin is one of the few rare metals with important strategic position in our country' but the technical limitations of the comprehensive utilization have led to the increasing scarcity of in ore resources' the large loss rate of useful components' and the increase in the amount of tailings over the years. Tailings not only occupy a lot of land' but also pollute the surrounding environment. Therefore, it has great significance of the green utilization of tin tailings resources to ensure the safety of tin mineral resources in China. In this paper, the current situation and characteristics of tin tailings resources at home and abroad was in reduced. It was summarized that it the key of secondary benefication of the in tailings is to solve the influence of sulfide minerals iron and manganese mineras and slime on comprehensive recovery of tine cassiterite and co-associated valuable components. Meanwhile, the technological characteristics and cases of tin tailings research status are also summarized. At present, the main methods to re-use tin tailings include recovery valuable metals by gravity separation, magnetic separation, flotation and combined beneficiation and metallurgy, used tailings as building materials or mining tailings as a whole, and treated waste stone containing tin as a special tailings to pre-concentrated. The common collectors and regulators of cassiterite flotation and their action mechanism were summarized. The researches which should be strengthen in the future were proposed, including enhancing the recovery of tine cassiterite, enhancing the new gravity separation equipment of cassiterite separation, enhancing the development of new green reagents, and enhancing development of new flotation equipment. The future development trend based on the research hot topic was proposed, with a view to providing reference for the green and efficient utilization of in tailings. [ABSTRACT FROM AUTHOR]

Stockpiles containing sulfide minerals are subject to oxidation reactions when exposed to atmospheric conditions, which can result in the formation of acid mine drainage (AMD). Reactive waste rock has limited re-use potential due to the contamination risk associated with the generated drainage water. The re-use of reactive waste rock could lead to a significant reduction in the volume of waste rock as it mitigates the environmental impact of mine waste deposition. Acid mine drainage generation rate depends on sulfide weathering kinetics which are controlled by many parameters such as the mineralogy and the particle size. Fine fractions of waste rock have higher specific surface areas and degree of liberation of sulfides, resulting in greater reactivity than the coarse fractions. The objective of this research was therefore to evaluate the potential of re-use by controlling particle size using the sieving method. Two different potentially acid-generating waste rocks were divided into six fractions and subjected to both static and kinetic tests. Prediction of the geochemical behavior using static test did not consider the liberation of the minerals, and the long-term prediction was therefore overestimated. Results of the kinetic columns showed there was less oxidation of the sulfide minerals in the coarse fractions than in the fine fractions. Additionally, the distribution of sulfidic minerals and neutralizing minerals with particle size is influencing the potential of the re-use of the reactive waste rock. [ABSTRACT FROM AUTHOR]

Heavy metals mainly exist on the surface of sediment particles and are transported using particulate matter as carriers. Therefore, the particle size of sediment particles can affect the adsorption, release, and migration of heavy metals. This study aim to investigate the distribution characteristics and chemical fraction of Cd, Pb, and As contents in sediments of different particle sizes using the BCR method, and to determine the key factors affecting the distribution of heavy metals through mineralogical methods such as XRD and EDS. The results revealed that the overall content of various forms of heavy metals increases with the decrease of particle size, mainly presents in fine particles. The mineralogical analysis results indicated that fine particles predominantly contained clay minerals such as chlorite and illite and coarse particles mainly include primary minerals. Due to the mining areas in the middle-upstream, Cd, Pb and As were primarily associated with galena, sphalerite and pyrite, respectively. The distribution of heavy metals is jointly influenced by sediment particle size and sediment material composition. [ABSTRACT FROM AUTHOR]

Gem-quality amethyst at the La Manche deposit in the Avalon Zone of Newfoundland, Canada, occurs in a calcitegalena- barite-quartz vein adjacent to a historical lead mine containing similar mineralization. The deposit has produced mineral specimens as well as medium to medium-dark purple (up to 11 ct) and light purple (<3 ct) faceted stones. Amethyst is interpreted to have formed as the final stage of hydrothermal mineral deposition in the veins. Variable color, zoning, and crystal size in different but contiguous crystal-lined pockets suggest relatively closed-system behavior within pockets where amethyst/quartz was deposited from trapped silica- and iron-bearing hydrothermal fluid. Microthermometry of primary fluid inclusions revealed an average homogenization temperature of 75.5 ± 6.9°C, cooler than in fluid inclusions within sulfide-bearing zones of similar veins in the region. Average fluid salinity estimated from primary inclusions in amethyst, recorded in weight % NaCl equivalent, was 10.7 ± 1.8 eq. wt.% NaCl. This was similar to the salinity of fluid in sulfide-bearing veins in the region and significantly higher than in quartz-chlorite veins in the region. Secondary fluid inclusions suggest a late influx of lower-salinity fluids (7 eq. wt.% NaCl) associated with postcrystallization deformation that internally fractured amethyst crystals, reducing the volume suitable for faceting. Mineral inclusions are most abundant in the final purple and colorless growth stages in amethyst. They consist of black to red hematite spherulites, acicular "beetle-leg" inclusions (likely hematite), pyrite, chalcopyrite, and sprays of ochre goethite. Late iron-rich accessory mineral deposition may have depleted the hydrothermal fluid of iron, the chromophore in amethyst, during the final growth stage. La Manche amethyst's inclusion mineralogy is similar to that of amethyst from the deposits at Thunder Bay (Ontario, Canada), but the morphology of accessory sulfide minerals is different. [ABSTRACT FROM AUTHOR]

The article presents the results of studies subject to establish the dependencies of thermal, mechanical and technological properties of highly filled polyphenylene sulfides depending on the mineral fillers introduced into the glass-filled polyphenylene sulfide. Mineral fillers differed in chemical and physical structure and nature. It is shown that the filling of glass-filled polyphenylene sulfide with powdered fillers does not affect the level of electrophysical properties, but significantly affects the physical, mechanical and technological characteristics of highly filled materials. [ABSTRACT FROM AUTHOR]

A calc–alkaline dioritic–andesitic–dacitic intrusive–volcanic complex of Early Oligocene (30 Ma) age and its Mesozoic sedimentary basement at Recsk host a well-preserved porphyry–skarn–polymetallic carbonate-replacement–epithermal mineral system. The unique occurrence offers an exceptional possibility to study these related mineralization types at a single locality. This study presents the textural–paragenetic, compositional characteristics, and systematics of sulfide mineral assemblages for the porphyry, skarn, and carbonate-replacement ore types, which are currently situated at a depth of 500–1200 m below the present surface. Detailed petrography combined with EPMA analyses of molybdenite, galena, sphalerite, tetrahedrite-group minerals and Bi-bearing sulfosalts allows for the establishment of characteristic mineral and chemical fingerprints for each mineralization type. Rhenium concentration in molybdenite, occurring as rare disseminations and quartz–carbonate veinlets in altered host rocks in all three mineralization types, shows a decreasing trend towards the more distal mineralization types. High Re contents ( x ¯ = 1.04 wt.%, max. up to 4.47 wt%) are typical for molybdenite from the porphyry mineralization, but Re is not homogeneously distributed, neither within individual molybdenite crystals nor on a mineralization scale. Copper and Se show opposite behavior in molybdenite, both becoming enriched in the more distal mineralization types. Silver, Bi, and Se concentrations increase in galena and tetrahedrite-group minerals, both towards the country rocks, making them the best candidates for vectoring within the whole hydrothermal system. For tetrahedrite-group minerals, Ag, Bi, Se, together with Sb and Zn, are the suitable elements for fingerprinting; all these are significantly enriched in the distal carbonate-replacement mineralization compared to the other, more proximal ore types. Additionally, further trends can be traced within the composition of sulfosalts. Lead-bearing Bi sulfosalts preferentially occur in the polymetallic carbonate-replacement veins, while being under-represented in the skarn and porphyry mineralization. Porphyry mineralization hosts Cu-bearing Bi sulfosalts dominantly, while skarn is characterized by Bi-dominated sulfosalts. Sphalerite, although present in all mineralization types, cannot be used for fingerprinting, vectoring, or thermobarometry based on EPMA measurements only. Trace element contents of sphalerite are low, often below the detection limits of the analyses. This is further complicated by the intense "chalcopyrite disease" occurring throughout the distal mineralization types. All the above-listed major, minor, and trace element ore mineral characteristics enable the characterization of the Recsk ores by mineral geochemical fingerprints, providing a possible vectoring tool in porphyry Cu–(Mo)–Au-mineralized systems. [ABSTRACT FROM AUTHOR]

The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor metacolloidal TiO2 phases to disordered anatase during seafloor alteration of hyaloclastites, which was later converted to globules and clusters and further to diagenetic rutile. The LA-ICP-MS analysis showed that the Ti content of hyaloclasts partly replaced by finely dispersed Si–Fe aggregates increases to 540–2950 ppm and decreases (<5 ppm) in full Si–Fe pseudomorphs after hyaloclasts. LA-ICP-MS element mapping reveals the enrichment in V, U, Cr, W, Nb, Pb, and Th of the anatase globules and the local accumulation of Zr, Y, and REE on their periphery. Corrosive biogenic textures in the outer zones of some hyaloclasts and biomorphic aggregates in rocks contain anatase particles in assemblage with apatite indicating the biophilic properties of Ti. This work fills the knowledge gaps about Ti mobilization during low-temperature seafloor alteration of hyaloclastites in VHMS deposits. [ABSTRACT FROM AUTHOR]

The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically distributed gabbroic intrusions. Four stages of mineralization and alteration have been identified: sodic alteration (I), banded sulfide (II), magnetite (III), and sulfide vein/stockwork (IV). Extensive sodic alteration of stage I is confirmed by the composition of feldspars. Trace element analysis of magnetite suggests a formation temperature of 400 ± 50 °C and has a characteristic of IOCG deposits, while high δ18O values (8.3–11.0‰) of fluids from stage III indicate a magmatic water origin. Sulfide δ34SVCDT values from stages II and IV range from −2.6 to 10.9‰ and −1.5 to 9.9‰, respectively, suggesting a mixed sulfur source from magmatic H2S and reduced seawater sulfate. Chalcopyrite from Hongnipo shows a narrow δ65Cu range of −0.135 to 0.587‰, indicating formation at high temperatures. The lack of correlation between δ65Cu and δ34SVCDT values suggests distinct geochemical behaviors in mineralization. In summary, the Hongnipo deposit is classified as a Cu-rich section of a typical IOCG deposit. [ABSTRACT FROM AUTHOR]

Gold grains are observed in a variety of forms, such as coarse-liberated native gold grains, and ultra-fine grains associated with sulfide or non-sulfide mineral particles, in the form of solid solution in sulfide minerals, mainly pyrite. In the flotation of gold ores, bulk sulfide mineral flotation is generally applied to maximize gold recovery. This approach gives high gold recoveries, but it also causes the recovery of barren sulfide minerals (i.e., sulfide mineral particles with no gold content), which increases concentrate tonnage and transportation costs and reduces the grade sometimes to below the saleable limit (approx. 10 g/t Au). This study addresses the differences between gold-bearing and barren pyrite particles taken from various ore deposits and utilizes these differences for the selective flotation of gold-bearing pyrite. The laboratory scale flotation tests conducted on three pyrite samples having different cyanide soluble gold contents show that a selective separation between gold-bearing pyrite and barren pyrite particles could be achieved under specific flotation conditions. Gold recovery is correlated directly with the cyanide-soluble gold in the ore samples. Electrochemical experiments were conducted to elucidate the differences in surface properties of the two types of pyrite. The barren pyrite particles were more cathodic and prone to cathodic reduction of OH− and depressant ions on the surface, and they could be depressed effectively without significantly affecting the gold-bearing particles. [ABSTRACT FROM AUTHOR]

The management of mine tailings presents a global challenge. Re-mining these tailings to recover remaining metals could play a crucial role in reducing the volume of stored tailings, as historical mining methods were less efficient than those used today. Consequently, mine wastes have the potential to become unconventional resources for critical minerals. To assess this potential, critical minerals and metals in the mine tailings were investigated through sampling, characterization, and 3D geostatistical modeling. The Bleïda copper mine tailings in Morocco were modeled, and residual copper resources were estimated using ordinary kriging (OK). Tailings were systematically sampled at a depth of 1.8 m using a triangular grid and tubing method. The metallic and mineralogical content of the samples was analyzed, and a numerical 3D model of the tailing's facility was created using topographic drone surveys, geochemical data, and geostatistical modeling. The results from the 3D block model of the Bleïda tailings facility reveal that the volume of deposited tailings is 3.73 million cubic meters (mm3), equivalent to 4.85 million tonnes (Mt). Furthermore, based on the average copper grade (~0.3% by weight) in the studied part of the tailings pond, the copper resources are estimated at 2760 tonnes. Mineralogical characterization indicates that this metallic content is mainly associated with sulfide and carbonate minerals, which exhibit a low degree of liberation. This study aims to serve as a reference for assessing the reprocessing feasibility of tailings in both abandoned and active mines, thereby contributing to the sustainable management of mine tailings facilities. Geostatistical modeling has proven effective in producing tonnage estimates for tailings storage facilities and should be adopted by the industry to reduce the technical and financial uncertainties associated with re-mining. [ABSTRACT FROM AUTHOR]

The concealed Molai Zn-Pb±(Ag,Ge) stratiform deposit in southeastern Peloponnese is hosted in Triassic intermediate tuffs, ignimbrites and subaerial andesitic flows. The host rocks display trace element signatures of a Supra-Subduction Zone (SSZ) setting. Three ore-forming stages are recognized, with stages I and II related to formation of the epigenetic, stratiform, massive-to-semi-massive ore and a late stage III associated with vein-type mineralization. The O and D isotope geochemistry of gangue chlorite and epidote reveal mixing with fresh meteoric water during the weaning stages of the hydrothermal activity of the late stage II due to uplifting of the hydrothermal system. Sphalerite is the major ore phase, with three different varieties formed during stages I (Sp-I) and II (Sp-II and Sp-III). All sphalerite varieties coexist, depicting gradual change in the chemistry of the ore-forming fluids. Molai ores are characterized by elevated Ag and Ge contents. Tetrahedrite is the major Ag carrier, while among the three sphalerite varieties, early Sp-I comprises the highest Ge contents. The Molai Zn-Pb±(Ag,Ge) deposit is characterized by intermediate features between bimodal felsic massive sulfides and subaerial epithermal systems based on the shallow formation depth, the presence of hydraulic breccias associated with phase separation, the ore formation along high-angle faults, the relatively low ore-forming temperatures below 250 °C obtained from geothermometry, and the absence of the typical structure of bimodal felsic type ores. [ABSTRACT FROM AUTHOR]

The Iberian Pyrite Belt (IPB) represents one of the largest districts of volcanogenic massive sulfide (VMS) deposits in the world, and is a critical source of base metals (Cu, Pb, and Zn) for Europe. Confirmed resources exceed 1700 Mt of massive sulfides with grades of around 1.2% Cu, 1% Pb, and 3% Zn as well as more than 300 Mt of stockwork-type copper mineralization. Significant resources of Sn, precious metals (Au and Ag), and critical metals (Co, Bi, Sb, In, and Se) have also been evaluated. The genesis of these deposits is related to a complex geological evolution during the late Devonian and Mississippian periods. The geological record of such evolution is represented by three main lithological units: Phyllite–Quartzite Group, the volcano–sedimentary Complex (VSC), and the so-called Culm Group. The sulfide deposits are located in the VSC, associated with felsic volcanic rocks or sedimentary rocks such as black shales. The massive sulfide deposits occur as tabular bodies and replacement masses associated with both volcanic and sedimentary rocks. Their mineralogical composition is relatively simple, dominated by pyrite, chalcopyrite, sphalerite, and galena. Their origin is related to three evolutionary stages at increasing temperatures, and a subsequent stage associated with the Variscan deformation. The present paper summarizes the latest developments in the IPB and revises research areas requiring further investigation. [ABSTRACT FROM AUTHOR]

Carbonates have been traditionally regarded as post-ore minerals in hydrothermal deposits, but they can also occur in pre- and syn-ore stages. However, the genetic relationships between multistage carbonates and gold precipitation mechanisms remain unclear. The Jinshan gold deposit, the largest gold deposit in the eastern Jiangnan orogen, is characterized by the occurrence of abundant hydrothermal carbonates. The nature of the carbonates, especially their association with gold precipitation, was examined in this study through petrographic and geochemical analyses as well as geochemical modeling. Field and petrographic work recognized four paragenesis stages in the Jinshan deposit: (1) quartz (Q1)-carbonate, (2) pyritequartz (Q2), (3) gold-polysulfide-quartz (Q3)-carbonate, and (4) chlorite-quartz (Q4)-carbonate. Carbonates associated with gold mineralization are mainly present in the first and third stages. Among them, the first-stage carbonates are pre-ore ankerites (Ank1), which are generally crosscut by synore sulfides. Such carbonates mostly occur in altered host rocks that are characterized by bleaching. Mineralogical and geochemical analyses revealed that chlorite was consumed while ankerite was produced, and Fe contents of the host rocks remained generally unchanged during alteration. Consequently, ankerite (Ank1) is interpreted to have been generated by the interaction of CO2-bearing fluids and chlorite in the host rocks. Geochemical modeling revealed that both Fe-bearing chlorite and ankerite (Ank1) can lead to gold precipitation by triggering sulfidation, but ankerite has higher chemical reactivity and therefore is kinetically favorable for more efficient gold deposition. Synore carbonates were mainly formed in the third stage, primarily consisting of ankerite (Ank2) with minor calcite, and they were coprecipitated with native gold, galena, sphalerite, and chalcopyrite. Two stages of carbonates shared similar δ13CVPDB values and Pb, Zn, and Cu contents but different Ca, Mg, Mn, and Sr contents, indicating they formed at different stages of the same hydrothermal event. Geochemical modeling demonstrated that pH increases, as indicated by the formation of syn-ore carbonates, together with the consumption of S due to the precipitation of pyrite and arsenopyrite in the second stage, resulted in the decrease of Au, Pb, Zn, and Cu solubility in aqueous fluids. This would have led to the coprecipitation of native gold with galena, sphalerite, and chalcopyrite, forming the general small-scale but commonly occurring native gold–polysulfide veins in the hydrothermal gold deposits. Consequently, both pre- and syn-ore carbonates in the Jinshan deposit were genetically associated with efficient Au-polymetallic deposition through distinct mechanisms. Pre-ore carbonates caused the large-scale bleaching of the host rocks, while syn-ore carbonates were closely related to native gold–polysulfides, and they can both be used as exploration indicators for the Jinshan deposit and other similar hydrothermal gold deposits worldwide. [ABSTRACT FROM AUTHOR]

The rhenium-osmium (187Re-187Os) system is a highly versatile chronometer that is regularly applied to a wide range of geological and extraterrestrial materials. In addition to providing geo- or cosmo-chronological information, the Re-Os system can also be used as a tracer of processes across a range of temporal (millennial to gigayear) and spatial scales (lower mantle to cryosphere). An increasing number of sulfide minerals are now routinely dated, which further expands the ability of this system to refine mineral exploration models as society moves toward a new, green economy with related technological needs. An expanding range of natural materials amenable to Re-Os geochronology brings additional complexities in data interpretation and the resultant translation of measured isotopic ratios to a properly contextualized age. Herein, we provide an overview of the 187Re-187Os system as applied to sedimentary rocks, sulfides, and other crustal materials and highlight further innovations on the horizon. Additionally, we outline next steps and best practices required to improve the precision of the chronometer and establish community-wide data reduction procedures, such as the decay constant, regression technique, and software packages to use. These best practices will expand the utility and viability of published results and essential metadata to ensure that such data conform to evolving standards of being findable, accessible, interoperable, and reusable (FAIR). [ABSTRACT FROM AUTHOR]

Germanium (Ge) is a critical raw material for emerging high-tech and green industries, resulting in considerable recent interest in understanding its distribution and geochemical behavior in ore deposits. In this contribution, the distribution of Ge and related trace elements in the Fule Pb-Zn(-Ge) deposit, South China, is investigated to reveal the distribution of Ge in the hydrothermal ores and during sulfide weathering, using multiple microanalytical techniques, including scanning electron microscopy, electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In the Fule MVT deposit, sphalerite (ZnS) is the most significant Ge-carrier relative to other sulfides, though the five recognized textural types of sphalerite display progressive depletion in Ge from the first sphalerite generation to the late one. In the early stage, sphalerite with fine-grained chalcopyrite inclusions has the highest Ge concentrations, probably accounting for a significant proportion of the total Ge. We interpret that high Ge concentrations in the early sphalerite may be attributable to high Cu activity in the mineralizing fluids. During oxidative weathering, Ge was redistributed from its original host, sphalerite, to the weathering product willemite (Zn2SiO4) rather than smithsonite (ZnCO3), with high levels of Ge (up to 448 μg/g) present in the willemite. The formation of abundant willemite largely prevents the dispersion of Ge during weathering. In principle, willemite-hosted Ge should be fully recoverable, and the Zn-silicate ores may, therefore, be a potential target to meet future demand. This study provides new information on how Ge behaves from sulfide- to weathering-stage in MVT systems, which directly impacts Ge mobility and deportment changes and the development of metallurgical strategies for Ge recovery. [ABSTRACT FROM AUTHOR]

The Paleo-Mesoproterozoic North Singhbhum Mobile Belt (NSMB) is a fold-thrust belt typically found in a collisional setting and is well known for hosting gold mineralisation. A study carried out in the northern part of NSMB depicts varieties of acid volcanic rocks along with mica schist, ferruginous cherty quartzite, black shale, and sheared granite, which are all ubiquitously traversed by quartz veins/reefs. In the study area, gold mineralisation is mostly restricted to brecciated quartz reef occurring ENE–WSW along S1 foliation, which also depicts syn to late kinematic brittle–ductile shearing. The petrographic studies of mineralised cherty variant of quartzite in quartz reef depict the presence of two generations of the quartz vein. The older one is smoky/bluish, altered, recrystallised and consists of disseminated and stringers of pyrite, chalcopyrite, etc., whereas the younger veins are milky white and lack mineralisation. The presence of pyrite–pyrrhotite and chalcopyrite–pyrrhotite associations and conversion of pyrite to pyrrhotite along fracture depicts prograde metamorphism. Trace elemental mineral chemistry depicts significant Au enrichment in pyrite. A positive correlation between Co and Ni concentrations in pyrite indicates hydrothermal origin. Au–As ratio explains the enrichment of gold in pyrite, where gold occurs as a solid solution in pyrite, which is generally referred to as invisible gold. The presence of gold grains/nuggets at the microscopic level and in pan concentrate as well as considerable analytical value in bulk rock coupled with occurrence in sulphide structure, points towards the bimodal nature of gold mineralisation. Mode of occurrence, nature of mineralisation, and surficial, structural and mineralogical characteristics suggest gold mineralisation of the study area is of orogenic type. [ABSTRACT FROM AUTHOR]

Copper tailings are a common byproduct of copper production, containing high levels of heavy metals which are released into the environment. Conventional methods have historically prioritized copper recovery, and often overlooking the leaching of other valuable elements. However, the rising demand for nonferrous metals necessitates understanding their leaching behavior from copper tailings. This study examined the atmospheric leaching of Cu, Fe, Pb, Zn, and CuO from a polymetallic tailing ore. Leaching recoveries of 63.5% for Cu, 97.5% for CuO, 1% for Fe, and 100% for Zn were achieved under the optimum conditions of 0.5 M sulfuric acid concentration, 25% solids percentage, 65°C, stirring speed of 100rpm, particle size of 75 µm within 30 minutes. Results indicated that the dissolution of oxide minerals such as CuO and ZnO was significant; however, copper sulfides need oxidant to be dissolved. In this condition, iron oxides and silicates were partially reacted by sulfuric acid, and Pb-bearing minerals formed lead sulfate. The presence of iron and lead-bearing minerals in the leaching residue was confirmed by XRF, XRD, and SEM analyses, and was in agreement with the information displayed in the Eh-pH diagrams. [ABSTRACT FROM AUTHOR]

Intermediate sulfidation epithermal deposits represent significant reservoirs of precious metals, playing a crucial role in global mining operations. The Anatolian Peninsula, predominantly characterized by relatively young (Tertiary) lithologies, hosts numerous occurrences of epithermal base and precious metal mineralization. Within the realm of research in Northeastern Anatolia, several hydrothermal alteration zones have emerged as indicators of concealed epithermal mineralization, with the Bahçecik mineralization standing out as a recent focal point. The Bahçecik mineralization represents an intermediate sulfidation epithermal Au-Ag system, hosted by Late Cretaceous andesitic rocks, as well as Eocene dacitic lava and tuffs. Employing U-Pb LA-ICP-MS zircon dating of the dacitic host rocks, the mineralization is estimated to have occurred during the Lutetian epoch (43.61 ± 0.35 Ma) or later. The genesis of the Bahçecik deposit is believed to be linked to postcollisional regional extensional tectonics, primarily controlling its structural arrangement. Comprising pyrite, chalcopyrite, low-Fe sphalerite, galena, tetrahedrite/tennantite, enargite-luzonite, and gold-silver minerals, the deposit is accompanied by prominent gangue minerals such as Mn- and Ca-carbonates, quartz, and barite. Microprobe measurements have identified a majority of Au-Ag minerals (krennerite, buckhornite, and nagyagite) closely associated with sulphide minerals. Fluid inclusion data reveal that mineralization and fluid transportation occurred at temperatures ranging from 153 to 327°C, with solutions exhibiting salinity levels consistent with those of intermediate sulfidation deposits (1.7–7.3 wt.% NaCl). This study unequivocally classifies the Bahçecik mineralization as an intermediate sulfidation deposit, contrary to the conclusions drawn in previous research. Moreover, our investigation has unveiled the presence of a substantial ore resource, totalling 7.84 million tons, featuring 1.76 g/t Au and 2.24 g/t Ag. As an intermediate-type deposit, it shares characteristics with other subtypes within the epithermal class, bridging the realms of both high and low sulfidation systems. [ABSTRACT FROM AUTHOR]

Exponential increasing demands for base metals have made meaningful processing of their quite low-grade (>1%) resources. Froth flotation is the most important physicochemical pretreatment technique for processing low-grade sulfide ores. In other words, flotation separation can effectively upgrade finely liberated base metal sulfides based on their surface properties. Various sulfide surface characters can be modified by flotation surfactants (collectors, activators, depressants, pH regulators, frothers, etc.). However, these reagents are mostly toxic. Therefore, using biodegradable flotation reagents would be essential for a green transition of ore treatment plants, while flotation circuits deal with massive volumes of water and materials. Pyrite, the most abundant sulfide mineral, is frequently associated with valuable minerals as a troublesome gangue. It causes severe technical and environmental difficulties. Thus, pyrite should be removed early in the beneficiation process to minimize its problematic issues. Recently, conventional inorganic pyrite depressants (such as cyanide, lime, and sulfur-oxy compounds) have been successfully assisted or even replaced with eco-friendly and green reagents (including polysaccharide-based substances and biodegradable acids). Yet, no comprehensive review is specified on the biodegradable acid depression reagents (such as tannic, lactic, humic acids, etc.) for pyrite removal through flotation separation. This study has comprehensively reviewed the previously conducted investigations in this area and provides suggestions for future assessments and developments. This robust review has systematically explored depression performance, various adsorption mechanisms, and aspects of these reagents on pyrite surfaces. Furthermore, factors affecting their efficiency were analyzed, and gaps within each area were highlighted. [ABSTRACT FROM AUTHOR]

Groundwater quality and availability in coastal aquifers have become a serious concern in recent times due to increased abstraction for domestic, agricultural and industrial purposes. (1) Background: Zhuhai city is selected as a representative coastal aquifer in Southern China to comprehensively evaluate the hydrochemical characteristics, spatial distribution and controlling mechanisms of groundwater. (2) Methods: A detailed study utilizing statistical analyses, a Piper diagram, Gibbs plots, and ion ratios was conducted on 114 surface water samples and 211 groundwater samples. (3) Results: The findings indicate that the pH of most groundwater is from 6.06 to 6.52, indicating a weakly acidic environment. The pH of surface water ranges from 5.35 to 9.86, with most values being weakly alkaline. The acidity in the groundwater may be related to the acidic atmospheric precipitation, an acidic unsaturated zone, oxidation of sulphide minerals and tidal action. The groundwater chemical types are predominantly mixed, followed by Ca-Mg-HCO3 type. Surface water samples are predominantly Na-Cl-SO4 type. The NO3− concentration in groundwater is relatively high, with a mean value of 17.46 mg/L. The NO2− and NH4+ concentrations in groundwater are relatively low, with mean values of 0.46 mg/L and 7.58 mg/L. (4) Conclusions: The spatial distribution of the principal chemical constituents in the groundwater is related to the landform. The chemical characteristics of groundwater in the study area are mainly controlled by the weathering and dissolution of silicate and sulfate minerals, evaporation, seawater mixing and cation exchange. Nitrate in clastic fissure groundwater, granite fissure groundwater and unconfined pore groundwater primarily originates from atmospheric precipitation, agricultural activities of slope farmland and forest land. Nitrate in confined pore groundwater and karst groundwater primarily originates from domestic sewage and mariculture wastewater. Our findings elucidate the processes characterizing the hydrogeology and surface water interactions in Zhuhai City's coastal system, which are relevant to other catchments with similar geological characteristics. [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 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.)

Jumun Island is tectonostratigraphically situated on the marginal zone of the Gyeonggi Massif. The Massif is in contact with the southwestern margin of the Imjingang Belt and adjacent to Boreum Island, where ultramafic rock with magmatic Fe-Ti oxide deposits occurs. The northwest of Jumun Island, facing the Boreum ultramafic rock with Fe-Ti oxide ores, is composed of Precambrian Boreumdo schists containing a few magmatic intrusives, the exact ages of which are unknown. In Jumun, the ultramafic intrusion (Mg# = 75), which is confined to a narrow zone along the seaside, mainly consists of olivine (Fo = 81–82), amphibole (magnesio-horn-blende to tremolite), and phlogopite. The olivine is strongly serpentinized and encompassed by amphibole and phlogopite. The Ni-Cu sulfide mineralization found in the ultramafic rock is weak but has a typical assemblage of pyrrhotite-pentlandite-chalcopyrite with a small amount of magnetite. Notably, the Ni-Cu sulfides are closely associated with amphibole and phlogopite and are found in the fractures and interstitials of the olivine grains. The pyrrhotite (n = 2) and chalcopyrite (n = 1) are compositionally close to pure samples, whereas the pentlandite (n = 2) is characterized by enrichment with Co (up to 6.9 wt%). The sphalerite-bearing quartz vein cuts across the Precambrian gneissic rock and strikes N70 °W with an 80 °NE dip. This vein, which is traceable to a limited extent and approximately 40 cm wide, shows mineralogical zonation in the inward direction from pyrite to sphalerite-dominant. Consisting of sphalerite, pyrite, quartz, and chlorite with minor amounts of chalcopyrite, pyrrhotite, and pentlandite, it is composed of 9.56 wt% Zn with < 1.0 wt% As, Co, Cu, In, Mn, Ni, and Pb and below-detection limits (0.001 ppm) amounts of Bi, Ge, Mo, Se, Sb, Te, and W. Sphalerite, a principal ore mineral, is coarse-grained and reddish-brown and is composed of 57.3–58.8 wt% ZnS, 8.0–9.2 wt% FeS, and 32.0–32.4 wt% S with small amounts of Cu, Mn, As, and Cd. The recently discovered Ni-Cu sulfide mineralization and quartz vein with sphalerite, along with the linear array of magmatic Fe-Ti oxide deposits, provide conclusive evidence that the marginal zone of the Gyeonggi Massif may be a geologically favorable area for the formation of magmatic and magmatic-hydrothermal deposits. For exploration purposes, it is necessary to contextualize the source, tectonic setting, and magmatic evolution. [ABSTRACT FROM AUTHOR]

If dihydrogen (H2) becomes a major part of the energy mix, massive storage in underground gas storage (UGS), such as in deep aquifers, will be needed. The development of H2 requires a growing share of H2 in natural gas (and its current infrastructure), which is expected to reach approximately 2% in Europe. The impact of H2 in aquifers is uncertain, mainly because its behavior is site dependent. The main concern is the consequences of its consumption by autochthonous microorganisms, which, in addition to energy loss, could lead to reservoir souring and alter the petrological properties of the aquifer. In this work, the coinjection of 2% H2 in a natural gas blend in a low-salinity deep aquifer was simulated in a three-phase (aquifer rock, formation water, and natural gas/H2 mix) high-pressure reactor for 3 months with autochthonous microorganisms using a protocol described in a previous study. This protocol was improved by the addition of protocol coupling experimental measures and modeling to calculate the pH and redox potential of the reactor. Modeling was performed to better analyze the experimental data. As in previous experiments, sulfate reduction was the first reaction to occur, and sulfate was quickly consumed. Then, formate production, acetogenesis, and methanogenesis occurred. Overall, H2 consumption was mainly caused by methanogenesis. Contrary to previous experiments simulating H2 injection in aquifers of higher salinity using the same protocol, microbial H2 consumption remained limited, probably because of nutrient depletion. Although calcite dissolution and iron sulfide mineral precipitation likely occurred, no notable evolution of the rock phase was observed after the experiment. Overall, our results suggested that H2 can be stable in this aquifer after an initial loss. More generally, aquifers with low salinity and especially low electron acceptor availability should be favored for H2 costorage with natural gas. [ABSTRACT FROM AUTHOR]

Pyrite is the most widely distributed sulfide mineral with a wide range of uses, and pyrite is mainly recovered by means of flotation in practical production, and the commonly used flotation collectors are mainly xanthates with good flotation performance. The adsorption behavior of commonly used collectors ethyl xanthate and butyl xanthate on the surface of pyrite is investigated by using the density functional tight bounding theory (DFTB). The results show that when a single reagent acts on the pyrite surface, butyl xanthate has a stronger effect than ethyl xanthate, and the adsorbed mineral surface shows obvious hydrophobicity. The interaction between ethyl xanthate and butyl xanthate had a stronger effect than that of a single reagent, and the simulation of the flotation environment at ordinary temperature using molecular dynamics revealed that the synergistic adsorption of the two different reagents on the surface of pyrite was more hydrophobic, that is, the synergistic adsorption of the combined collector of ethyl xanthate and butyl xanthate on the surface of pyrite was stronger. The results of the study are of great significance for the synergistic effect between the combined collector and the mineral. [ABSTRACT FROM AUTHOR]

The lack of mineralization research on metamorphic rocks in Java, especially in the Jiwo area, is part of the research interest. The host rock of ore mineralization in the Jiwo area is Cretaceous metamorphic rock located in the hilly area of Jiwo, Klaten, Central Java. The presence of chlorite, actinolite, quartz, epidote, and garnet minerals indicates the metamorphic facies of greenschist. Meanwhile, the presence of glaucophane, quartz, and epidot minerals is a metamorphic facies of blueschist. The metamorphic rock research method was carried out in several stages: 1. Observation; 2. Field data collection, including mapping of metamorphic rock distribution, general geological conditions and rock sampling; and 3. Laboratory analysis. Laboratory analysis testing consists of petrography, ore microscopy, geochemistry (AAS), and fluid inclusion. Alterations that develop in the researched area are in the form of propylitic (chlorite, calcite, epidote), argillic, and silicification (quartz, graphite, calcite, carbonate minerals). Ore microscopy analysis has identified the presence of mineral sulfide such as pyrite, chalcopyrite, bornite, galena, and covellite. In addition, galena was found covered with chalcopyrite. Based on AAS analysis on mineralized metamorphic rocks, Au levels are 0.001 - 0.008 g/t, Ag 0.1 - 2.4 g/t, Cu 4 - 75 g/t, Zn 14 - 166 g/t, and Pb 11 - 60 g/t. The inclusion of fluid from the discordant vein was obtained with a homogenization temperature (Th) of 312 - 435 0C, with a salinity of 1.95 - 5.05 wt. % eq. with isothermal mixing and heating depressurization conditions. The isothermal mixing process is a mixture of meteoric fluids and metamorphic fluids. Meanwhile, heating depressurization occurs during subduction, so that the temperature is relatively high. The homogenization temperature (Th) of the concordant vein ranges from 168.5 - 296.55 °C, with a salinity of 1.95 -12.6 wt% NaCl eq. A salinity of 12 wt% NaCl is formed due to liquids that are aquos trapped at high pressure and temperature conditions and the devolatilization process that occurs during subduction. Based on the plotting of the homogenization temperature range and the salinity of fluid inclusion, which is 168.5 - 4350C and 1.95 - 12.6 wt% NaCl eq, the type of deposits in the study area is in the range of Au lode or orogenic deposits. The existence of two homogenization clusters in the Jiwo Hill is estimated to be part of the process of forming the blueschist facies with greenschist which is shown in the retrograde actinolite in the glaucophane epidote schist rock which is part of the blueschist facies. [ABSTRACT FROM AUTHOR]

The Pulang giant porphyry Cu-Mo polymetallic deposit is located in the Zhongdian area in the center of the Sanjiang Tethys tectonic domain, which was formed by the westward subduction of the Garze-Litang oceanic slab beneath the Zhongza massif. Chalcopyrite-pyrrhotite-pyrite-molybdenite occurs as disseminations, veins, veinlets, and stockworks distributed in the K-silicate alteration zone in the monzonite porphyry, which is superimposed by propylitization. The chemical compositions of biotite and amphibole analyzed by electron probe microanalysis (EPMA) indicate that the ore-forming magma and exsolved fluids experienced a continuous decrease in the oxygen fugacity (fO2). Primary amphibolite and biotite (type I) crystallized at relatively high temperatures (744–827 °C) and low fO2 (logfO2 = − 12.26 to − 11.91) during the magmatic stage. Hydrothermal fluids exsolved from the magma have a relatively lower temperature (621–711 °C) and fO2 (logfO2 = − 14.36 to − 13.32) than the original magma. In addition, the presence of a high abundance of pyrrhotite and an insufficiency of primary magnetite and sulfate in the ore (i.e., anhydrite and gypsum) indicate that the deposit may be a reduced porphyry deposit. Magma and fluid fO2 results, combined with previous research on magmatic fO2 at the Pulang deposit, indicate that the magma associated with the reduced Pulang ore assemblages was initially generated as a highly oxidized magma that was subsequently reduced by sedimentary rocks of the Tumugou Formation. [ABSTRACT FROM AUTHOR]

A low grade copper gold ore in Mongolia contains 0. 20 g/t gold, 0. 24% copper, 1. 80% sulfur and 1.7% magnetic iron. Copper minerals are mainly the chalcopyrite mineral, a small amount of Bornite and copper blue;The other sulfides are mainly pyrite; Magnetic minerals are mainly magnetite and hematite, which can be recovered comprehensively. Based on the ore properties of low content of target minerals and fine distribution size, the flotation magnetic process of 11 Cu S bulk flotation mixed concentrate regrinding Cu S separation comprehensive recovery of Fe from bulk flotation tailings 11 was recommended, and the closed circuit flotation test obtained a copper gold bulk concentrate containing 20. 30% copper and 11. 44 g/t gold, with recoveries of 86. 00% copper and 69. 40% gold. A final iron concentrate containing 65.34% iron was then obtained by the flotation magnetic process, with recoveries of 23. 80% iron and 91. 70% magnetic iron. Compared with the original process, iron resource in flotation tailings can be comprehensively recovered while copper and gold concentrate grade were significantly improved. [ABSTRACT FROM AUTHOR]

Platinum-group elements (PGEs) have a strong affinity for sulfur and tend to accumulate in the deep continental crust, either concentrated within magmatic Cu-Ni-PGE deposits or dispersed throughout disseminated sulfides. However, PGE enrichment in shallow magmatic-hydrothermal systems implies an obscure link to deep sulfide destabilization, which releases PGEs into ore-forming fluids. To bridge this gap, our study investigates the PGE composition of magmatic sulfides with oxidative textures in dacitic rocks from the southwestern Okinawa Trough. We identified three groups of magmatic sulfides, primarily precipitated as Cu-poor monosulfide solid solution (MSS), which formed at distinct stages of magma evolution from deep to shallow crustal levels. Group A sulfides manifest as small-sized inclusions (<30 μm) within most high-Mg olivines, whereas Group B and C sulfides are larger (50–500 μm) and occur within cognate xenoliths of mafic cumulate rocks and the groundmass of host dacites. Group B and C sulfides exhibit distinct oxidative textures and newly-formed mineral assemblages, including magnetite, hematite, goethite, and magnetite ± pyrite, alongside hydrothermal silicate minerals, respectively. We attribute the oxidation process to the infiltration of orthomagmatic fluids exsolved from mafic magma that had underplated the sulfide-bearing felsic magma reservoir, which was nearly solidified. By comparing the chemical compositions between pristine sulfides and their oxidative remnants, we observed extensive mobilization of Pd, Pt, Cu, Ag, Ni, and Co from the altered sulfides of Group B, while Au enrichment occurred as nanoparticles under high oxidation states. In contrast, Au was extracted along with other mobile metals from the altered sulfides of Group C, with Pt remaining in place under more reduced conditions. These distinct scenarios may lead to the formation of PGE-rich and Au-rich fluids, respectively. The formation of deep crustal MSS and subsequent hydrothermal oxidation under varying redox conditions thus provides a viable mechanism for trans -crustal PGE mobilization and inter-element fractionation, typical of PGE-rich magmatic-hydrothermal deposits. [ABSTRACT FROM AUTHOR]