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Degraded water quality and environmental impacts caused by weathering of sulfide-bearing mine wastes are a legacy remaining at many historical mine sites. Release and mobilization of toxic metals (e.g., Zn and Cd) in mine drainage are often associated with weathering of primary sulfide minerals and precipitation and dissolution of secondary minerals. This study aims to couple field-scale measurements of physicochemical parameters with μm- and nm-scale mineralogical characterization to investigate sphalerite weathering and controls on Zn and Cd migration in an uncovered mine waste-rock pile. Elevated concentrations of Zn and Cd, potentially harmful to the receiving environment, were detected in waste-rock pore water and seepage. A suite of analytical techniques, including scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDS), scanning transmission electron microscopy (STEM) with EDS, electron microprobe analysis (EMPA), and synchrotron-based micro X-ray fluorescence (μ-XRF) mapping and micro X-ray absorption near edge structure (μ-XANES) spectroscopy were utilized in a high-resolution investigation of elemental- and secondary-mineral associations with sphalerite grains. EMPA and μ-XRF elemental maps and STEM investigations show depletion of Zn, Fe, S, and Cd, local enrichment of Cu, and distinct dissolution pits at the margins of sphalerite grains. Using μ-XANES, the speciation of solid phases containing Zn, Cu, Fe, and S indicates the dominance of primary sphalerite with microscopic inclusions of chalcopyrite, along with sparse occurrence of secondary Cu-bearing sulfides formed during weathering. These results suggest sphalerite oxidation leads to congruent dissolution without formation of distinct secondary-mineral coatings. Sphalerite weathering significantly contributes to elevated aqueous concentrations of Zn and Cd. Field-scale observations and mineralogical investigations indicate common occurrence of Fe-oxyhydroxides in the waste-rock pile. Seepage chemistry and surface complexation modeling results suggest that pH-dependent variations in reactions on the surfaces of the Fe-oxyhydroxides control aqueous concentrations of Zn and Cd, and the Zn/Cd ratio in the seepage. This work highlights the importance of understanding the mechanisms of sulfide-mineral oxidation and subsequent surface precipitation and adsorption, such that appropriate remediation action can be implemented to limit mobilization of metals to sensitive ecosystems.

Tracking the S oxidation pathway in sulfide-bearing mine waste-rock piles is complicated by variations in water content, O2 and Fe3+ concentrations, microbial diversity, mineralogy, the occurrence of a variety of S species associated with incomplete oxidation, and nonlinear coupling between physicochemical processes. Synchrotron-based S K-edge X-ray absorption near edge structure (XANES) spectroscopy facilitates the identification and quantification of S species (i.e., S2-, S22-, S8, S2O32-, and SO42-) in a naturally weathered mine waste-rock pile containing pyrite, sphalerite, galena, pyrrhotite, and chalcopyrite. Mineralogy-dependent polysulfide and thiosulfate pathways both affect the S oxidation within the waste-rock pile. Currently, the polysulfide pathway, with S8 as the intermediate S species, generates high concentrations of dissolved metals (from the rapid oxidation of monosulfides including sphalerite, galena, pyrrhotite, and chalcopyrite). As these monosulfides are depleted, the thiosulfate pathway of pyrite oxidation, including intermediate oxidation products (i.e., S8 and S2O32-), will become the dominant oxidation pathway, resulting in the potential for generation of additional acidic drainage. This information highlights the importance of identifying the sulfide-mineral oxidation reaction pathways when attempting to estimate acid generation potential, and when developing remediation strategies for the storage and management of sulfide-bearing waste rock.

TThe electronic and optical properties of sphalerite (ZnS) are modulated by adsorbing alkali metals (Li, Na, K, Rb, Cs) and halogen (F, Cl, Br, I, At). Simulations based on density‐functional theory are used to study the electronic and optical properties of pristine sphalerite and alkali‐halogen adsorbed sphalerite structures. The results suggest that pristine sphalerite has high absorption in several portions of ultraviolet (UV) region (λ < 250 nm) and negligible absorption in the visible and IR region. The alkali‐halogen adsorbed structure of sphalerite results into red‐shift phenomenon in which an increase in absorption coefficient with wavelength is observed or spectrum shifting towards the red end is observed. Strong absorption for both alkali and halogen adsorbed nanostructures is found throughout the visible zone (~410 to 780 nm) of the spectrum. Bromine adsorbed sphalerite structure results in highest value of absorption in visible region in comparison to other alkali and halogen adsorbed structures. This shift in absorption peaks from UV region to desired visible region range is beneficial for optoelectronic applications and in fabrication of optoelectronics devices such as LED, ARC, solar cells, CRTs and sensors.

Haerdaban is a newly discovered Zn–Pb deposit (0.64 Mt at 6.19 wt% Zn and 1.09 wt% Pb) in the Western Tianshan, NW China. Sulfide mineralization mainly occurs as veins, breccias, and semi-massive ores within the dolomitic limestone and calcareous slate. Here we use Rb–Sr sphalerite and SHRIMP U–Pb zircon geochronology to place constraints on the age and formation of the deposit. Rb–Sr dating of sphalerite gives an isochron age of 432 ± 45 Ma (n = 6; 87Sr/86Sri = 0.7102 ± 0.0020), providing a direct age constraint for the main mineralization. SHRIMP U–Pb data for detrital zircon from three samples of host siliceous dolomite have relatively similar age modes with prominent age peaks at 1576 Ma, 1781 Ma, and 1848 Ma, and a smaller peak at 1375 Ma. The maximum depositional age for the host dolomite is constrained at 1099 ± 21 Ma by the weighted mean age of the four youngest detrital zircons. These results demonstrate that the main mineralization clearly postdates the host sedimentary rocks. Zircons from two diorite samples and one granite sample yield overlapping 206Pb/238U ages with a weighted mean of 394.5 ± 1.5 Ma. This age is slightly younger but within analytical uncertainty of the 432 ± 45 Ma for the ores, implying a possible temporal relationship between intrusions and main mineralization. The igneous intrusions could provide the heat to drive the hydrothermal system responsible for main-stage mineralization. Haerdaban is interpreted to be a metamorphosed SEDEX Zn–Pb deposit that has been remobilized by subsequent hydrothermal activity.

Hydrometallurgical leaching process has been identified as a viable procedure for recovering metals of value from their matrices. The optimization of zinc recovery from sphalerite in nitric acid solution was carried out in this study. The Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) and Particle Swarm Optimization (PSO) tool in matlab were deployed for the optimization studies. RSM modeling gave optimum conditions of 73.0 °C leaching temperature, 3.48 M acid concentration, 0.027 g/mL solid/liquid ratio, 411.02 rpm stirring rate, and 82.82 minutes leaching time; with a zinc yield of 87.67 %. With PSO, about 86.9 % zinc was recovered at a leaching temperature of 69.1 °C, acid concentration of 1.8 M, solid/liquid ratio of 0.031 g/mL, stirring rate of 270 rpm and leaching time of 85 minutes. Thus, PSO and RSM proved to be good optimization tools.

The Baiyinnuo’er deposit in northern China is located in the south section of the Great Xing’an Range, and it is the largest skarn Zn–Pb deposit in the region. Skarn and Zn–Pb orebodies mainly occur between the different units of the Permian Huanggangliang Formation, or within the contact zone between the intrusive rocks and the marble. Although Baiyinnuo’er has been well investigated previously, the timing of the Zn–Pb mineralization is still controversial, largely due to the lack of appropriate ore or alteration minerals that could be directly used for isotopic dating. In this study, we report the results of Rb–Sr isotopic analysis for sphalerite and pyrite samples from the Baiyinnuo’er orebodies, which yielded two isochron ages of 137.4 ± 3.4 and 140.0 ± 7.8 Ma, respectively, constraining the Zn–Pb mineralization time of the deposit as the Early Cretaceous. The data are also consistent with the age of the granitoids in the mining area, indicating a potential genetic relationship between the Early Cretaceous magmatism and mineralization. Many other intrusion-related hydrothermal deposits (including the two typical skarns, Huanggang and Haobugao) in the southern Great Xing’an Range also share similar mineralization ages (i.e., 140–130 Ma). Together, these data suggest an Early Cretaceous mineralization event in this region, and this large-scale mineralization could be related to the regional tectonic regime transition from compression to extension as a result of the rollback of the subducted Paleo-Pacific plate. The initial 87Sr/86Sr ratios of the sphalerite and pyrite samples are 0.70569 and 0.70616, respectively, implying that the ore-forming material could have a significant contribution from the mantle components. The current study shows that sulfide Rb–Sr dating could be used in deciphering the timing of skarn deposit formation.

Ссылка для цитирования: Золото в рудах золото-колчеданного месторождения Абыз (Центральный Казахстан) / А.К. Мазуров, А.Н. Николаева, М.А. Рудмин, Т.Ю. Якич, А.С. Рубан, Ш.Ж. Байболова // Известия Томского политехнического университета. Инжиниринг георесурсов. – 2021. – Т. 332. – № 11. – С. 78-88 Актуальность исследования. В Чингиз-Тарбогатайской структурно-формационной зоне известно более 20 золото-колчеданных месторождений. Все месторождения объединяет одна проблема: при обогащении руд значительная часть золота переходит в «пиритный» концентрат и теряется вместе с «хвостами». В целях увеличения извлечения золота нами был детально изучен минеральный состав руд наиболее представительного золото-колчеданного месторождения Абыз. Установлено, что значительная часть золота на месторождении представлена минералом электрумом, который заполняет микротрещины в пирите и халькопирите. При разработке технологической схемы извлечения золота, вероятно, данному факту не было уделено должного внимания, так как считалось, что золото в пирите представлено самородным золотом. Цель: изучить текстурно-структурные особенности руд, а также установить минеральную форму нахождения золота в рудах месторождения Абыз и его связь с основными сульфидными минералами (пирит, халькопирит, галенит и сфалерит). Методы исследования включали изучение состава горных пород и руд с использованием минералогического, петрографического, минераграфического и геохимического анализов. Результаты. По структурно-текстурным свойствам на месторождении выделены вкрапленные и сплошные руды. Установлено, что основное количество золота, ассоциирующееся в основном с пиритом и редко халькопиритом, связано со сплошными рудами и представлено в минеральной форме. Золотая минерализация сопряжена с процессами березитизации; отложение минералов Au происходило в рудную стадию минералообразования и связано с золото-сульфидной и золото-теллуридной ассоциациями. Преобладающим минералом является электрум AgAu, в меньшей степени диагностируется самородное золото Au и единично обнаружен петцит Ag3AuTe2 с калаверитом AuTe2. Доминирующими минералами- концентраторами в рудах являются такие сульфиды, как пирит и халькопирит. Причину потери большей части золота в результате флотации можно объяснить тем фактором, что низкопробный золотосодержащий минерал электрум AgAu является господствующим.

Unusual hydrothermal native As-sulfide ± native Ag ± arsenide ± antimonide ± sulfosalt ore shoots and their co-genetic sulfide-fluorite-barite-quartz host veins, which are common in the region and in whole Central Europe, were investigated at three localities in the Schwarzwald, SW Germany, to understand the physico-chemical processes governing the change from a normal (= common) hydrothermal to an exceptional ore shoot regime. Based on fluid inclusions, the formation of the gangue minerals is the result of binary mixing between a NaCl-rich brine and a CaCl2-rich brine (both ~ 20 wt% NaCl aq.). This mixing correlation, major and minor fluid composition, formation temperature (~ 150 °C), and δ34S signature are identical (within error) in ore shoots and host veins. Thermodynamic modeling indicates that ore shoot formation must have resulted from a change in redox conditions by a local influx of a volumetrically minor reducing agent, probably hydrocarbons. The elemental content and the mineralogy of each ore shoot locality (Ag-As-rich: Münstertal; Ag–Ni-As-rich: Urberg; Ag–Ni-As-Sb-rich: Wieden) reflect the metal content of the binary mixed fluid, while mineral textures, successions, and assemblages are thermodynamically and, regarding sulfur, kinetically controlled. The formation of vein and ore shoot sulfides requires an addition of sulfide, most probably from the sulfide-bearing host rocks, because thermodynamic and kinetic reasons suggest that the two major vein-forming and metal-bearing fluids are not the source of the sulfur. The final ore shoot textures are influenced by later hydrothermal remobilization processes of As and Ag. This results in a number of sulfosalts, mostly proustite-pyrargyrite. Interestingly, the greater thermodynamic stability of Sb-endmember sulfosalts enables them to form even in As-dominated fluid systems., Eberhard Karls Universität Tübingen (1020)

Background. Some papers describing the deposits and prospects in the Baimka ore zone (Baimka Trend), the Chukotka Autonomous Region have been recently published. It should be noted that those publications concern with the large Peschanka porphyry copper-molybdenum-gold deposit and Nakhodka ore field. At the same time, some copper prospects were found at the zone flanks and their nature is not clear. There are no data available in the literature that would clarify the mineralogy of hydrothermal alteration and ores at those prospects, including Top and Luchik located at the northern flank. To understand the nature of these prospects, we studied in depth mineralogy of hydrothermal alteration and ores.Aim. This study aims to describe mineralogy of metasomatic rocks and ores from the Top and Luchik prospects in the northern part of the Baimka zone, Western Chukotka.Materials and methods. Several dozen polished thin sections were microscopic studied at the Department of Mineralogy of Moscow State University using an optical microscope. The chemical composition of minerals was determined using electron microprobe at the Laboratory of Analytical Techniques of High Spatial Resolution, Department of Petrology and Volcanology, Moscow State University.Results. It was found that propylitic is the major hydrothermal alteration at the prospects studied here. Metasomatic rocks are cut by mineralized quartz and carbonate-quartz veins. Chalcopyrite and pyrite are the major ore minerals; galena, sphalerite, pyrite enriched in As and Sb, and marcasite are minor; Hg-bearing tetrahedrite-(Zn), native gold with the fineness of ~830, petzite, hessite, and acanthite are rare.Conclusions. The data obtained suggest that mineralization at the Top and Luchik prospect is attributed to the epithermal intermediate sulfidation type. Considering the occurrence of the epithermal mineralization in the upper part of the hydrothermal column and the porphyry mineralization in the Baimka zone, the porphyry mineralization is possible at depth at the Top and Luchik prospects.

We investigated the 53Mn-53Cr isotopic composition of a suite of enstatite chondrites by in situ analyses of various mineral phases with the Cameca IMS 1280-HR ion probe at Heidelberg, Germany, and a Cameca NanoSIMS at Paris, France. Only in sphalerite we found anomalies in 53Cr/52Cr-ratios correlating with 55Mn/52Cr which are due to decay of short-lived 53Mn (t1/2 = 3.7 Ma). A sphalerite in the EH-impact melt LAP 02225 showed the largest excess of 53Cr, with 53Cr/52Cr-ratios ranging up to 2.2. The calculated initial 53Mn/55Mn-ratios are within the range of previous Mn-Cr studies. We observed a spatial variation within a large sphalerite in LAP 02225, translating in distinct initial 53Mn/55Mn values. In case of the EL3 chondrite MAC 88136 the initial 53Mn/55Mn derived for one sphalerite is at the lower end of previously reported values and may reflect a variable influence of alteration-induced exchange of common Cr. This is supported by the total reset of the 53Cr/52Cr-ratio in another sphalerite in contact with an alteration vein irrespective of high Mn/Cr-ratios. Our observed initial 53Mn/55Mn-ratios of Sahara 97158, Indarch and EET 96135 correspond to the I-Xe systematics and hence, show that sphalerites can preserve reasonable age information. For Indarch however, if compared with other initial 53Mn/55Mn values from literature, a considerable scatter is obvious. This clearly demonstrates that the Mn-Cr system in sphalerite can be disturbed by various, still poorly investigated, processes (e.g., by thermal events, weathering, diffusion-controlled remobilization). Future application of Mn-Cr dating to sphalerite in enstatite chondrites thus requires a better understanding of how such processes influence the Mn-Cr systematics and demands for tools to identify the undoubtly present sphalerites carrying a true chronologic information.

Studies of the mineralogy and sulfur isotope composition of sediment-hosted hydrothermal sulfide minerals in cores are important for understanding the seafloor mineralization environment and material source and reconstructing the hydrothermal history. However, the source of ore-forming materials and the history of hydrothermal activity in the southern Okinawa Trough (SOT) remain unclear. Here, the mineralogy and sulfur isotope characteristics of sulfides from gravity core HOBAB4-S2, collected between the Yonaguni Knoll IV hydrothermal field (HF) and the Tangyin HF, was investigated. Enrichments in Zn (up to 321×10−6), Cu (up to 73.7×10−6), and Pb (up to 160×10−6) and the presence of pyrite, galena, pyrrhotite and minor sphalerite and chalcopyrite provide evidence for the input of hydrothermal materials into the sediments. The pyrite morphologies include disseminated cubic, pentagonal dodecahedron, and framboidal forms. Except for minor framboidal pyrite, euhedral pyrite from core HOBAB4-S2 is mainly of hydrothermal origin with Co/Ni ratios >1 and S/Fe atomic ratios

A wide variety of Zn–Pb deposits have been reported along the Malayer–Esfahan metallogenic belt in Iran. This metallogenic belt is localized in the central part of the Sanandaj–Sirjan zone. In the present study, sphalerite and galena chemistry of four Zn–Pb deposits (i.e., Gol-e-Zard, Baba-Gholleh, Tekyeh and Emarat deposits) are examined in this area. Also, fluid inclusion studies from four deposits were examined to study possible relationships between trace element chemistry of sphalerite and galena with ore-bearing fluid. The homogenization temperatures increase on average from 94.89 °C (the Tekyeh deposit), 116.83 °C (for the Emarat) to 166.14 °C (Baba-Gholleh deposit) and 181 °C (the Gol-e-Zard). The salinity increases on average from 8.68 wt.% NaCl equivalent (the Tekyeh), 9.33 wt.% NaCl equivalent (the Emarat), to 11.19 wt.% NaCl equivalent ( the Gol-e-Zard) and 12.1 wt.% NaCl equivalent (the Baba-Gholleh). Samples from the Tekyeh and Emarat are typically enriched in Fe, Cu, Cd, Ga, and Ge, while these elements less abundant in the Gol-e-Zard and Baba-Gholleh deposits with Zn/Ag, Zn/Fe, Zn/Cu, Ga/In and Sn/In ratios in sphalerites of two types of Zn–Pb deposits are different. The Tekyeh and Emarat galena are strongly enriched in Ag, Cd and Ge. Based on geological evidence and host rocks, fluid inclusion studies are compared between trace elements in sphalerite with some Zn–Pb deposits. We conclude that Gol-e-Zard and Baba-Gholleh deposits are of sedimentary exhalative type, whereas Emarat and Tekyeh deposits are classified as Mississippi valley type.

© 2021 Taylor & Francis Group, LLC.In this study, the flotation behaviors of gold and gold-associated sulfide minerals (pyrite and sphalerite) in a polymetallic sulfide gold ore were investigated using flotation kinetics parameters. It was found that high gold recovery (>90%) can be achieved by the selective flotation of pyrite and sphalerite. However, the sphalerite flotation results showed that sphalerite could not be separated from pyrite with a high selectivity (selectivity index∼1), because of insufficient depression of pyrite (with high alkaline medium and/or using a depressant). Even if more selective separation was achieved from the pyrite flotation (selectivity index∼5), 40% of sphalerite in the ore was transferred into the pyrite concentrate. In addition, the results of the collectorless tests indicated that more than 80% of the gold can be recovered, and higher selectivity indexes (up to 10) are achievable. Analysis of the particle size distribution of the collectorless flotation concentrate showed that the amount of −40 μm in the concentrate was 90%. In conclusion, a gold concentrate containing low sulfur (10.8%) with a gold recovery of greater than 95% is achievable from a two-stage flow sheet (collectorless flotation as the rougher stage and pyrite flotation as the scavenger stage).

Neves Corvo is an underground high-grade Cu–(Sn)–Zn mine, located in the Portuguese part of the world-class Iberian Pyrite Belt (IPB), which is currently producing copper, zinc, and lead concentrates. The operation is owned by SOMINCOR, a subsidiary of Lundin Mining, with a maximum capacity of 2.6 Mtpy for the copper processing plant and 1.0 Mtpy for the zinc processing plant. From 2010 till end of 2019, the mine has accumulated 7.3 Mt of waste rock and 17 Mt of thickened tailings. These mining residues are stored in Cerro do Lobo Tailings Management Facility (Cerro do Lobo TMF), which completes a volume of 47 Mt since the beginning of the operation in 1989 (30 Mt are slurry tailings). The deposition method changed in 2010 from slurry subaquatic deposition to sub-aerial thickened tailings stack (vertical expansion) in co-deposition with potentially acid-generating (PAG) waste rock. X-ray fluorescence analysis have shown copper and zinc grades variation in the waste rock between 0.12 and 0.4%, and 0.1% and 0.3%, respectively, and concentrations up to 0.6% and 1.3% of copper and zinc, respectively, in the tailings. Mineralogically, the tailings consist mainly in pyrite, sphalerite, chalcopyrite, ± arsenopyrite, ± tetrahedrite-tennantite, and gangue minerals such as quartz, phyllosilicates, carbonates, and some oxides, and have a non-uniform particle size distribution ranging between 1 and 100 µm. The waste rock fraction is millimetric to centimetric in size and is formed by the local host rocks, mineralogically consisting in quartz, chlorite (clinochlore and chamosite), calcite, and variably abundant disseminated sulfides, largely dominated by pyrite. Both mining residues might be envisaged as materials with valorization potential both for base metal recovery (tailings) and/or as non-metallic raw materials for construction or other applications (waste rock).

Abstract Paragenetic associations of tetrahedrite-(Zn) and sphalerite are distinguished in the Teremki gold-ore deposit. The chemical composition of coexisting minerals of this association is determined. The Sb/(Sb + As) and Fe/(Fe + Zn) ratios in tetrahedrite-(Zn) vary from 0.66 to 0.97 and from 0.28 to 0.40, respectively. A negative correlation was established between Sb/(Sb + As) and Fe/(Fe + Zn) ratios. Contents of Fe in sphalerite change from 0.88 to 1.43 wt % (1.5–2.5 mol % FeS). Temperature and sulfur fugacity when precipitation of tetrahedrite-(Zn)–paragenesis were estimated: they range from 130 to 280°C and from 10–13.2 to 10–8.1 bars, respectively.

The main activity of the Talvivaara Mining Company Plc. is the development and exploitation of the Talvivaara deposits in Sotkamo, Finland using bioheapleaching. The Talvivaara deposits comprise one of the largest known sulphide nickel resources in Europe with 1004 million tonnes of ore, sufficient to support anticipated production for a minimum of 45 years. The mine started in late 2008 and will have an annual nickel output of approximately 50,000 tons when it reaches full production. In addition, the mine will also produce zinc (approximately 90,000 tpa), copper (approximately 15,000 tpa) and cobalt (approximately 1,800 tpa) as by-products of the process. The viability of bioheapleaching technology for the extraction of nickel has been demonstrated in a large on-site pilot trial using Talvivaara ore. The three year pilot has shown that the leaching process also works well in the subarctic climatic conditions of Eastern Finland. The Talvivaara deposits are located in the southern part of the Kainuu belt in Eastern Finland. They comprise two different polymetallic orebodies, which are located approximately three kilometres apart. The deposits are outcropping and relatively easy to mine. The mineral resources have been classified by Australian JORC code with 0.07% Ni cut-off at 1004 million tons, containing 0.23% of nickel, 0.51% of zinc, 0.13% of copper and 0.02% of cobalt. The black schist ore and the possible utilization of the deposits have been extensively studied for over 20 years. It was quickly apparent from the ore dressing tests that a usable nickel concentrate was not achievable due to the high graphite content of the ore. Chemical and biological leaching options had to be considered as potential options (RIEKKOLA-VANHANEN, 1999). Talvivaara black schist ore contains pyrrhotite, pyrite, sphalerite, pentlandite, violarite, chalcopyrite and graphite. The main silica containing phases are quartz, mica, anorthite and microcline. In addition to nickel, zinc, copper and cobalt the ore contains about 0.3 % of manganese, 10 % of iron, 9 % of sulphur, 8 % of carbon and 50 % of SiO2. The distribution of nickel in different sulphides is pentlandite 71 %, pyrrhotite 21 % and pyrite 8 %. The distribution of cobalt is pentlandite 11 %, pyrrhotite 26 % and pyrite 63 %. All copper is in chalcopyrite and zinc in sphalerite. 2. Production process Overview. The mining method at Talvivaara is large scale open pit mining. Materials handling covers all physical ore processing steps from the primary crusher to

Laser ablation-inductively coupled plasma-mass spectrometry and electron-probe microanalysis were used to investigate the trace-element contents of sphalerite, chalcopyrite and pyrite from the Plaka Pb–Zn–Ag deposit. Using petrographic observations, the analytical results could be linked to the temporal evolution of the Plaka ore-forming system. Sphalerite chemistry reliably records the temperature and fS2 evolution of the system, with estimated formation temperatures reproducing the microthermometric results from previous fluid-inclusion studies. Chalcopyrite chemistry also shows systematic variations over time, particularly for Cd, Co, Ge, In, Sn and Zn concentrations. Measurable pyrite was only found in association with early high-temperature mineralisation, and no clear trends could therefore be identified. We note, however, that As and Se contents in pyrite are consistent with formation temperatures estimated from co-existing sphalerite. Statistical analysis of the sphalerite data allowed us to identify the dominant geological controls on its trace-element content. The three investigated factors temperature, fS2, and sample location account for > 80% of the observed variance in Mn, Fe, Co, Ga, Ge, In, Sb and Hg concentrations, and > 60% of the observed variance in Cd and Sn concentrations. Only for Cu and Ag concentrations is the explained variance, Deutscher Akademischer Austauschdienst http://dx.doi.org/10.13039/501100001655, Helmholtz-Zentrum Dresden - Rossendorf e. V. (4213)

The Masjed Daghi porphyry-epithermal Cu-Au-Mo deposit in the northern Arabian-Eurasian collision zone of the Alborz Magmatic Assemblage, NW Iran, is hosted by an early Miocene quartz monzodiorite to diorite intrusion that intruded Eocene volcanic rocks. Potassic, phyllic, argillic, and propylitic alterations associated with four stages of porphyry mineralization (I to IV) are distinguished. Late high-sulfidation epithermal veins of mainly quartz or quartz-barite are enclosed in concentric zones of advanced argillic, argillic, silicic, and propylitic alterations. Poly-phase brine inclusions from the stage ΙΙ porphyry mineralization have homogenization temperatures (Th) between 305 and 600 oC, with salinity from 30.2 to 73.9 wt% NaCl equivalent. Brines inclusions of stages ΙΙΙ and ΙV have Th from 192 to 466 oC and salinity from 20.6 to 59.2 wt% NaCl equivalent. These brine inclusions were trapped with vapor-rich inclusions, which have Th from 122 to 318 oC and low-moderate salinity of 0.3 to 22.3 wt% NaCl equivalent. Fluid inclusions from quartz and sphalerite in epithermal veins yielded Th ranges of 123–298 °C and 121–218 °C, and salinity ranges of 1.9–12.8 and 1.9–11.2 wt% NaCl equivalent, respectively. The δ34S values of sulfide minerals from stages ΙΙ and ΙΙΙ porphyry mineralization vary from + 0.9 to + 2.3‰, whereas the δ34S values of sulfides from the late epithermal veins range from + 1.2 to -1.1‰. These characteristics are consistent with a similar magmatic source for both the fluids of porphyry mineralization and subsequent high-sulfidation epithermal veins. The Masjed Daghi deposit that represents a telescoped porphyry-epithermal system of copper–gold mineralization in the center and peripherals of the early Miocene intrusive stocks shows both similarities and differences to other Tethyan deposits in the Alpine-Himalayan orogenic belt.

In the present work, a biosurfactant-producing and sulfur-oxidizing mixotrophic bacterium (identified as Citrobacter sp.) was studied as flotation reagents to substitute for several hazardous chemical reagents to establish a cleaner and greener mineral processing. The mixotrophic bacterium Citrobacter sp. was adapted with galena (PbS) concentrate or sphalerite (ZnS) concentrate or silica (SiO2) mineral to modify the hydrophobicity of mineral surfaces as described by contact angle measurements, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM–EDS), and Fourier transform infrared (FTIR) spectroscopy. Furthermore, the bacterium application as potential flotation reagents in the bioflotation of complex Pb–Zn ore in a 2.5-l laboratory-scale Denver flotation cell showed that the mixotrophic bacterium could function as flotation bioreagents by producing metabolites apart from its bacterial cells. The bacterial action as flotation bioreagents included collector, frother, and depressant due to its capability in producing biosurfactants and oxidizing sulfur with a moderate capacity in oxidizing iron. Its function yielded the high flotation recovery of lead (Pb: ~ 90%) and zinc (Zn: ~ 80%) and higher Pb and Zn grade in concentrate with respect to pH, conditioning time, and bacterial cell concentration. From an industrial viewpoint, the findings of this study might be very prospective for the improvement of more cost-effective and eco-friendly flotation reagents.

Hydrothermal organic reactions in the presence of mineral catalysts have been well established by laboratory experiments. However, little is documented about hydrothermal catalytic conversion (HTCC) and the metastable existence of complex molecules in continental hydrothermal systems. Five freshly mined ores containing oil and solid bitumen and associated unmineralised host sediment were sampled from the Beichang mine, Jinding Zn/Pb ore deposit, Lanping, near the Indo-Eurasian collisional margin, southeastern Tibetan Plateau. Here we show evidence for a wide range of mineral (ZnS/PbS) catalysis of polycyclic aromatic compounds in the natural subsurface. An interpretation of hydrothermal alteration (non-biodegradation) was made for the unresolved complex mixture. From unmineralised host sediment through oils to the solid bitumen, a stepwise interaction of organic compounds with metal-bearing hydrothermal fluids was demonstrated by the transformation of polycyclic aromatic hydrocarbons (PAHs) and phenyl/sulfur/oxygen-containing compounds that are thought to be generated through HTCC. Thermodynamically-unstable phenyl derivatives (ortho- or α-substituted) resulted from hydrothermal alteration (ring opening) of the middle and naphthenic (low energy) rings of peri-condensed parent PAHs, as supported by the dominance of 1-phenyldibenzothiophene, 1-phenyldibenzofuran, triphenyleno[1,12-bcd]thiophene, triphenyleno[1,12-bcd]furan, 9-phenylphenanthrene, 1,1′:2′,1′′:2′′,1′′′-quaterphenyl, and the corresponding thiophenes or furans over other isomers. Heteroatom addition to phenyl-derivatives generates abundant heterocyclic compounds, which can undergo further dehydrocyclisation. In the presence of ZnS/PbS, the abundance of three compound classes (unsubstituted PAHs, ‘aryl-aryl’ linked phenyl-derivatives, and S/O atom-containing compounds) is mainly hydrothermally controlled, rather than thermodynamically controlled. Various phenyl/sulfur/oxygen-containing compounds are the metastable equilibrium products of a series of complex redox reactions under specific hydrothermal conditions. We hypothesise that the ubiquitous triphenyleno[1,12-bcd]furan is an important marker for hydrothermal organic–inorganic interactions in the Zn/Pb deposit. The relative abundance of 9-phenylphenanthrene provides a measure of the degree of hydrothermal alteration and HTCC. Our data is consistent with a close interaction of ascending metalliferous hydrothermal fluids with indigenous organic matter/compounds. Hydrothermal fluids, in the presence of sphalerite (and/or galena), are highly effective for activation of the carbon–carbon bonds in PAHs.

Highlights • Decoupling of volatile element enrichment and magmatic volatile influx. • Multiple sulfide generations with distinct trace element signatures. • Boiling-induced pyrite precipitation revealed by textures and Tl/Pb, Sb/Pb and Bi/Pb ratios. • Boiling-induced Au, electrum and Bi-telluride colloids lead to high Au grades. • Metals sources: shallow upflow- (60–80%) and deep reaction (20–40%) zone. Abstract Shallow (30 ppm) in the mature and late stage of chimney formation. Lead isotope data indicate that the hydrothermal fluids scavenged metals not only from the deeper basement in the reaction zone (20–40%), but also from young dacitic volcanic rocks near the seafloor in the upflow zone (60–80%). Sulfur isotope (δ34S = −0.3 to 4.4‰) and Se/S*106 values (

The late Palaeozoic Yong’an–Meizhou depression belt is an important iron (Fe) and polymetallic metallogenic belt in southern China. It has undergone a transformation from Tethys to the circum-Pacific tectonic domain. The Luoyang deposit is one of the typical Fe skarn deposits in the Yong’an–Meizhou depression belt of eastern China. Garnet is a characteristic mineral in the deposit. Two generations of garnets are detected in the deposit based on their textural characteristics and trace-element contents, and are represented by Fe-enriched andradite. The first generation of garnets (Grt1) have two types of garnets (Grt1-A and Grt1-B). Type A garnets of the first generation (Grt1-A) (Adr80-88) replaced by massive diopside-magnetite assemblage exhibit distinct oscillatory zonings and display patterns of enriched light rare earth elements (LREE) to weak heavy rare earth elements (HREE), with weak negative to positive Eu anomalies, and highest U, ΣREE and Sn contents. Type B garnets of the first generation (Grt1-B) are irregular zones (Adr94-96) coexisting with magnetite, in which Grt1-A is generally dissolved, and have obviously LREE-enriched and HREE-depleted patterns, with weak negative to positive Eu anomalies, and moderate U, ΣREE and Zn contents. Garnets of the second generation (Grt2) (Adr96-99) that replaced massive magnetite together with sphalerite show unzoned patterns, with a flat REE pattern and pronounced negative Eu anomalies as well as contents of lowest U and ΣREE, and highest W. The substitution of REEs in garnets occurs as [X2+]VIII –1[REE3+]VIII +1[Si4+]IV –1[Z3+]IV +1in an Al-enriched environment. Luoyang hydrothermal fluids shifted from reducing conditions with relatively high-U and -ΣREE characteristics to oxidizing conditions with relatively low-U and -ΣREE characteristics. The reduced siderophile elements and increased fO2 in fluid during Grt1-B formation caused magnetite mineralization and reduced Zn contents during Grt2 formation, causing the deposition of sphalerite. All garnets formed from magmatic fluid and were controlled by infiltrative metasomatism in an opened system.

Chemistry - a European journal 27(49), 12558 - 12565 (2021). doi:10.1002/chem.202101260, echanochemistry, as a synthesis tool for inorganic materials, became an ever-growing field in material chemistry. The direct energy transfer by collision of the educts with the milling media gives the possibility to design environmental-friendly reactions. Nevertheless, the underlying process of energy transfer and hence the kinetics of mechanosynthesis remain unclear. Herein, we present in situ synchrotron X-ray diffraction studies coupled with pressure measurements performed during the formation of ZnS and the subsequent phase transition (PT) from the hexagonal to the cubic modification. Milling Zn and S$_8$ results in the sublimation of S$_8$, observed by a sudden pressure increase. Simultaneously, the hexagonal metastable ZnS-modification (wurtzite) forms. Via detection of the pressure maximum, the exact start of the wurtzite formation can be determined. Immediately after the formation of wurtzite, the structural PT to the thermodynamic stable cubic modification sphalerite takes place. This PT can be described by the Prout-Tompkins equation for autocatalytic reactions, similar to thermally induced PT in sulfur vapor at high temperatures (T>1133 K). The increase in the reactivity of the wurtzite formation is explained by the reaction in sulfur vapor and the induction of defect structures by the collisions with the milling media., Published by Wiley-VCH, Weinheim

The influence of high concentration Zn2+ on the floatability of sphalerite in an acidic system was investigated via flotation experiments, zeta potential measurements, contact angle measurements, and X-ray photoelectron spectroscopy. The results indicated that Zn2+ was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn2+ concentration of 4×10−2 mol/L. The zeta potential increased and the contact angle decreased from 84.80° to 36.48°, strongly inhibiting the floatability of sphalerite. When S2− or Cu2+ activator was used alone, sphalerite was not activated after Zn2+ was adsorbed, and its contact angle did not change significantly. However, by using a combination of S2− and Cu2+ activators, its floatability was realized after Zn2+ adsorption. This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S2−. After this removal, Cu2+ was adsorbed on the sphalerite surface to form a Cu2S·S0 hydrophobic film.

The aim of this work has been to examine the effect of intensive ball milling of sphalerite in the wet and dry modes on the microstructural changes and the subsequent effect on its dissolution rate. Sample characterization showed that the BET surface area and the amorphization degree were obtained to 18.2 m2/g and 78.92% in the wet mode and 7.72 m2/g and 90.35% in the dry mode milling after 180 min, respectively. The maximum extraction of Zn obtained 23.7, 67.12 and 85% in the unmilled, wet and dry milled samples, respectively. The ratio of kinetic rate constant has been increased by 37 and 67 times, respectively. Also, the activation energy was decreased with increasing of milling time. Selectivity of sphalerite leaching versus surface area was obtained higher than that of the wet milling. Leaching experiments indicated that structural disordering had a drastic effect on the reactivity of mechanically activated sphalerite.

The Pogromnoye Deposit related to gold–sulfide-quartz formation of the veinlet-disseminated ore type was formed in the shear zone that occurs between overthrusts in the block confined to the volcanogenic–sedimentary basin along the fragment of the Mongol–Okhotsk suture. The parageneses of zonal quartz–albite–micaceous (muscovite–sericite) metasomatic formation related to the profile of moderate acid leaching are presented in ore-related metasomatites. The ore-related metasomatic replacements are interpreted to be Early Cretaceous and dated as far back as 139.5 ± 1.8 Ma. The absolute age of gold-bearing stockwork formation is associated with the termination of hydrothermal ore activity of the Amudzhikan–Sretensky Complex at 131 ± 1.2 Ma. Ore minerals are dominantly arsenopyrite, pyrite, secondary sphalerite, chalcopyrite, pyrrohotite with sulfosalts, gersdorffite, accessory molybenite and magnetite. The diffusion coefficient of As was calculated in zonal metacrystals of gold-bearing arsenopyrite and pyrite in the ores. The temperature interval of gold ore deposition during the formation of ore-bearing metasomatite equal to 350–150oC is validated by the physico-chemical data on mineral equilibria and fluid inclusions and the thermodynamic calculations performed using the SELECTOR software. Gold mineralization was generated by sulfoarsenide hydrothermal solution containing gold as thioarsenites AuAs $${\text{S}}_{2}^{0}$$ and H2AuAs $${\text{S}}_{3}^{0}$$ with hydrosulfide AuHS0, concentrations of dissolved S ≥ 0.01–0.001 m and As ≥ 0.005–0.0005 m, respectively.

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The studied sulfide mineralizations of Atshan and Darhib areas are related to the south Eastern Desert shear zones. They are hosted in talc- and tremolite-talc-rich rocks and also in meta-basaltic dykes and quartz-veins. The principal mineralization in Atshan includes sphalerite, pyrite, chalcopyrite, galena and pyrrhotite, whereas that in Darhib comprises chalcopyrite, sphalerite, pyrite, and galena with subordinate bornite and covellite. Darhib mineralization contains traces of altaite and electrum. Altaite has the highest Te concentrations suggesting crystallization under low fS2 and/or high fTe2 conditions, probably due to S budget consumption from the hydrothermal fluids in the late stage of deposition. Electrum has the highest Au contents with gold fineness value falling within the range of epithermal Au–Ag deposits. The dominance of recrystallized and replacement textures in the studied mineralizations suggests a secondary or post-depositional metamorphic overprint. The significant Cd contents in sphalerite from remobilized massive mineralizations hosted in tremolite-talc-rich rocks indicate crystallization at ~250–300 °C. Galena hosted in tremolite-talc-rich rocks is characterized by exceptionally high selenium and tellurium contents, indicating its generation from relatively Se–Te-enriched hydrothermal fluids. Pyrrhotite hosted in quartz-veins from Atshan was formed under lower sulfur activity (aS2) and oxygen fugacity (fO2). Covellite and bornite were formed due to chalcopyrite oxidation, revealing a role of supergene process. Shear zones, possibly produced during later thrust faulting, were acted as channel ways for hydrothermal mineralizing fluids that may have modified and/or precipitated the mineralization. Mineralizing fluids have probably resulted from dehydration during metamorphism and/or late-magmatic fluids from nearby granitic intrusions.

Environmentally friendly flotation reagent, polyaspartic acid (PAPA), was tested as a potential selective depressant in the flotation separation of chalcopyrite and Cu-activated sphalerite. The depression mechanism of PAPA was revealed by contact angle measurements, Zeta potential measurements, Fourier transform infrared spectroscopy (FT-IR) analysis and inductively coupled plasma (ICP) measurement. The micro-flotation tests with single minerals showed that PAPA selectively depressed Cu-activated sphalerite, while chalcopyrite remained floatable. Moreover, a concentrate containing 31.40% Cu with a recovery of 92.43% was obtained in flotation tests of artificially mixed minerals. Results of contact angle measurements, Zeta potential measurements and FT-IR spectrum revealed that PAPA exerted a much stronger adsorption on Cu-activated sphalerite surface than on chalcopyrite surface, preventing the further adsorption of sodium diethyl dithiocarbamate (DDTC) on its surface. ICP measurements indicated that PAPA had an excellent complexing ability with Cu2+ in flotation pulp, weakening the activation of Cu species on sphalerite surface and producing selective depression.

The structure of Ag2S/ZnS nanoheterostructures has been analyzed taking into account the morphology and elastic properties of Ag2S and ZnS sulfide single crystal particles. The arrangement of S atoms in (111) planes of cubic argentite β-Ag2S and sphalerite ZnS has been considered. The elastic stiffness constants $${{c}_{{11}}}$$ , $${{c}_{{12}}}$$ , and $${{c}_{{44}}}$$ of cubic argentite and sphalerite at a temperature of 300 K has been estimated. It has been shown that the formation of Ag2S/ZnS heterostructures where the interface is formed by the (111) planes of cubic sphalerite ZnS and argentite β-Ag2S is the most probable morphologically and energetically. The calculated universal criterion of the anisotropy of the elastic properties has shown that the studied cubic silver and zinc sulfides are elastically anisotropic.

The Hehuashan sediment-hosted Pb–Zn deposit is a large-scale (Pb + Zn＞1 Mt) deposit hosted in the Tongling mining district of the Middle-Lower Yangtze River belt (MLYB). The Pb–Zn ore bodies are composed of two main mineralization types, namely breccia type and massive type. The breccia type ore bodies are hosted by the Triassic limestone and dolostone, while the massive ore bodies are hosted by marble dolostone which are close to the diorite intrusions. The previous research showed that the Hehuashan Pb–Zn deposit is a Mississippi Valley-type (MVT) deposit formed in Middle Triassic and overprinted by late mineralization of magmatic-hydrothermal fluids in Yanshanian period. In this research, we aimed to declare the age of the late mineralization and it's relationship with diorite intrusions. The mineralization age (132.8 ± 3.1 Ma) of the massive ore rocks (late mineralization) is similar to the zircon U–Pb age of the diorite (133–130 Ma), showing that this type mineralization is contemporaneous to the Yanshanian intrusive events. Furthermore, similar initial 87Sr/86Sr values between sphalerite and diorite indicating a magmatic fluid was involved during the mineralization process and the emplacement of diorite also might have provided ore-forming materials. The heavy sulfur compositions (δ34S = +8.6‰ to +12.8‰) of the sphalerite in massive ore rocks indicate that the sedimentary sulfate may have provided reduced sulfur for sulfides precipitation by sulfate thermochemical reduction process. Sr–Nd isotopic compositions of the diorite in the Hehuashan deposit area showed that the massive Pb–Zn mineralization was related to the intrusion of diorite in an extensional tectonic setting. In summary, the Hehuashan Pb–Zn deposit composes a late Yanshanian Pb–Zn mineralization event and represents a younger Pb–Zn mineralization in the Tongling district and MLYB. The Triassic carbonates have the potential for Pb–Zn deposit exploration in the Tongling district and Middle–Lower Yangtze River belt.

The Kyaukmyet prospect is one of the principal epithermal gold prospects in the Monywa District, Central Myanmar; its gold- and base metal-bearing quartz veins contain around 3 g/t gold. Ore minerals are mainly hosted by volcanic and volcaniclastic rocks of the Late Oligocene to Middle Miocene Magyigon Formation. The distribution of magmatic intrusions in the area is controlled by ENE-WSW trending faults; these faults are likely related to ore mineralization. Common ore minerals at the Kyaukmyet prospect include pyrite, sphalerite, galena, chalcopyrite, and electrum. They occur in mineralized crustiform-textured brecciated quartz veins and banded (colloform) and massive quartz veins. Mineralized rock is accompanied by silicification and propylitic and argillic alterations. The alteration mineral assemblages include quartz, adularia, calcite, chlorite, illite/smectite, sericite, and illite. Fluid inclusions in the quartz veins have homogenization temperatures ranging from 148 °C to 304 °C and salinities from 0.35 wt % to 2.75 wt % NaCl equiv. The quartz in the mineralized quartz veins was most likely precipitated at a depth ranges165-256 m below the paleosurface. The precipitation of gold at the Kyaukmyet prospect may have been formed by mixing large amounts of meteoric fluid with small amounts of magmatic fluid. The coexistence of liquid-rich and vapor-rich inclusions and presence of adularia and bladed calcite indicate that fluid boiling is caused the main mechanism of ore formation. The vein textures, ore mineral assemblages, alteration minerals and fluid inclusion data suggest that the Kyaukmyet prospect is a polymetallic low-sulfidation epithermal gold deposit.

Laser ablation-inductively coupled plasma-mass spectrometry was used to traverse hydrothermal vein sphalerite from different ore-forming stages of the Porgera Au-Ag mine, Papua New Guinea. Elements were measured in situ over the growth of crystals to investigate the greatly varying concentrations of cations in sphalerite and their positions in the lattice. Traverse profiles for 16 elements were obtained and aligned to transmitted light images where possible. Each sample contained an array of elements, with many displaying orders of magnitude concentration differences. Results show the simultaneous incorporation of Cu and Sn in sphalerite, as well as Cu and Ag, In and Sn, As and Sb, Fe and Mn, and Cu and Ga. The relation [4Zn2+ ↔ 2Cu+ + Sn2+ + Sn4+] is proposed to explain the 1:1 Cu–Sn correlation. Further relations can be seen, including a Ga “ceiling” or Cu “floor”, where Ga incorporation becomes dependent on Cu concentrations. Furthermore, silver was also observed to correlate with Au, Mn, Ni, Pb, and Bi. Meta-stable solid solutions between pairs such as Cu, Ag; Fe, Mn; As, Sb; and In, Sn are also suggested. Each of these pairs are neighbors on the periodic table of elements, which suggests that simple solid solution can occur, and positive correlations for all four solid solutions were found in one sample alone. While the concept of charge-specific solid solutions in sphalerite has been discussed in the literature with reference to monovalent cations, the results presented herein also indicate solid solutions of higher oxidation states, containing many cations. Furthermore, while cations in charge-specific solid solutions have been proposed to compete for lattice sites in sphalerite, simultaneous in situ coupled concentrations at Porgera suggest otherwise. Cationic substitution equations displaying decimal ratios of each element in solid solution can then provide a novel method to distinguish between solid solution concentrations in different samples. For example, displaying 1:1 ratios of Cu–Ag and Sb–As: [2Zn2+ ↔ (Cu+0.5, Ag+0.5) + (As3+0.5, Sb3+0.5)], or for a 100:1 Fe–Mn ratio: [Zn2+ ↔ (Fe2+0.99, Mn2+0.01)].

Tirtomoyo in Wonogiri district is known as an ore mineralization region, in which one of the prospects occurred is Hargosari. No previous studies on the ore characteristucs have been done. A set of study on Hargosari prospect is aimed to characterize gold mineralization covering some aspects such as mineralogy, textures, ore chemistry and ore forming condition. To achieve the objectives, some research methods were performed suh as mapping, sampling and laboratory analyses for selected samples on term of petrography, ore microscopy and ore chemistry. Oligo-Miocene andesitic lava from Panggang Formation is identified as host rock. Opening system of veins is of jogs type to form en-´echelon tension gash veins. Quartz veins are enveloped by argillic and propylitic alteration zones, in association with pyrite, chalcopyrite, sphalerite, galena, gold, silver, chrysocolla, covellite and hematite. The approximately 5 cm thick quartz veins exhibit massive, swarm, low angle veins and stockwork structures, which is characterized by normal banded, crustiform, comb and saccaroidal textures. The quartz veins contain high base metals of up to 5.45% Cu, 9.9% Pb and 12.85% Zn, with significant grade of gold and silver of up to 3.85 g/t Au dan 395 g/t Ag. From mineral assemblages, the veins might be formed at temperatures of about 250-300°C. On the basis of those mentioned characteristics, gold mineralization in Hargosari prospect is categorized into an intermediate sulfidation epithermal. Keywords: characteristics, gold, epithermal, Hargosari, Wonogiri.

The new mineral grimmite, NiCo 2 S 4 , was found in siderite–sphalerite gangue at the dump of shaft no. 9, one of the mines in the abandoned Přibram uranium and base-metal district, central Bohemia, Czech Republic. The new mineral occurs as rare idiomorphic to hypidiomorphic grains up to 200 µm × 70 µm in size or veinlet aggregates. In reflected light, grimmite is creamy grey with a pinkish tint. Pleochroism, polarising colours and internal reflections were not observed. Reflectance values of grimmite in the air ( R %) are 42.5 at 470 nm, 45.9 at 546 nm, 47.7 at 589 nm and 50.2 at 650 nm). The empirical formula for grimmite, based on electron-microprobe analyses ( n= 13), is Ni 1.01 (Co 1.99 Fe 0.06 Pb 0.01 Bi 0.01)Σ2.07 S 3.92 . The ideal formula is NiCo 2 S 4 ; requires Ni 19.26, Co 38.67, and S 42.07; and totals 100.00 wt %. According to the single-crystal X-ray diffraction data ( Robs=0 .0489), grimmite is cubic, Fd–3 m , a=9 .3933(9), with V=828 .81(14) A 3 and Z=8 . The calculated density is 4.96 g cm −3 . The strongest reflections of the calculated powder X-ray diffraction pattern [ d , A (I)(hkl)] are 3.3210 (75) (220), 2.7116 (7) (222), 2.3483 (81) (400), 1.9174 (27) (422), 1.6605 (100) (440), 1.4852 (11) (620) and 1.3558 (15) (444). Grimmite is named after Johann Grimm (24 June or 24 July 1805 to 26 June 1874), the former director of the Přibram Mining College. The association of sulfides and sulfarsenides was found with grimmite. Essentially non-zoned coarse-grained siderite encloses idiomorphic crystals and/or aggregates of red sphalerite I and zoned skutterudite-group minerals. Skutterudites (skutterudite, niklskutterudite and ferroskutterudite) are usually strongly corroded and replaced by younger phases. Relics of skutterudite are rimmed by nickeline and later on by gersdorffite with rare domains of glaucodot and arsenopyrite, whereas completely leached parts of skutterudite crystals are filled up by quartz containing small isolated grains and aggregates of pyrite, sphalerite II, grimmite, galena, ullmannite, bismuthinite, parkerite and jaipurite, the latter being rarely enclosed in grimmite.

The Baiyangping Cu–Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, between the Jinshajiang-Ailaoshan and Lancangjiang faults, and the deposit can be divided into eastern and western ore zones. Based upon microscope observation of ore minerals and analysis of zinc, copper, and strontium isotope composition, we conclude that: (1) the zinc isotopic compositions of sphalerite from the eastern and western ore belt of the Baiyangping polymetallic ore deposits are enriched in both the heavy (− 0.09‰ to + 0.15‰) and light (− 0.19‰ to − 0.01‰) zinc isotopes. Rayleigh fractionation is likely the additional factor controlling the observed temporal and spatial variations in zinc isotopes in the two studied ore zones. The zinc isotopic composition in the Baiyangping polymetallic Pb–Zn deposits may have the same fractionation as that of magmatic-hydrothermal, VHMS, SEDEX, and MVT deposits, as demonstrated by geological and other geochemical evidence; (2) the range of δ65Cu in massive tetrahedrite is from − 0.06‰ to + 0.12 ‰ that relates to the early stages of ore-formation, which are higher than that of venial chalcopyrite (from − 0.72‰ to − 0.07‰) formed at a late ore-forming stage in the western ore belt. Different ore-forming stages and alteration or leaching processes are likely the main factors controlling the observed variations in copper isotopes in the western ore zone; (3) the 87Sr/86Sr value of hydrothermal calcite in eastern (0.7080–0.7093) and western (0.7085–0.7113) ore belt suggested that mineralization of early calcite, with 87Sr/86Sr values much higher than in ancient Late Triassic seawater, may be related to recrystallization from a radiogenic Sr-rich or silicifying fluid, either from the strata that the ore-forming fluid flows through or from other fluids.

Zinc is currently extracted from sphalerite (ZnS) by either sintering-smelting or roasting-leaching. These high-temperature processes produce environmentally hazardous sulfur dioxide gas. Hence, sustainable zinc extraction calls for direct leaching at low temperatures. Here, we show that ferric methanesulfonate is a high performing lixiviant for this purpose. Using 0.8 M ferric methanesulfonate, 99.3% Zn was extracted from 106−150 μm sphalerite particles after leaching at 70 °C for 96 h. Elemental sulfur, rather than sulfur dioxide, was produced as a by-product. When compared to common inorganic lixiviants such as ferric sulfate or ferric chloride, ferric methanesulfonate demonstrates greater extraction efficiency and is less corrosive, less toxic, and does not release harmful gases. Mineralogical, microscopical, and compositional characterization of reaction products confirmed the formation of a core–shell structure consisting of a sphalerite core and a sulfur shell, and the manifestation of a coupled dissolution-reprecipitation mineral replacement mechanism. Efficient zinc extraction was facilitated by the interconnected pores in sulfur, which provided pathways for mass transfer between the lixiviant and sphalerite core. The precipitation of anglesite (PbSO4), which in some instances caused surface passivation through the infilling of sulfur shells, suggests that Pb2+ concentration should be controlled when applying ferric methanesulfonate for Zn extraction.

Seafloor massive sulphide (SMS) deposits, modern analogues of volcanogenic massive sulphide (VMS) deposits on land, represent future resources of base and precious metals. Studies of VMS deposits have proposed two emplacement mechanisms for SMS deposits: exhalative deposition on the seafloor and mineral and void space replacement beneath the seafloor. The details of the latter mechanism are poorly characterised in detail, despite its potentially significant role in global metal cycling throughout Earth’s history, because in-situ studies require costly drilling campaigns to sample SMS deposits. Here, we interpret petrographic, geochemical and geophysical data from drill holes in a modern SMS deposit and demonstrate that it formed via subseafloor replacement of pumice. Samples from the sulphide body and overlying sediment at the Hakurei Site, Izena Hole, middle Okinawa Trough indicate that sulphides initially formed as aggregates of framboidal pyrite and matured into colloform and euhedral pyrite, which were replaced by chalcopyrite, sphalerite and galena. The initial framboidal pyrite is closely associated with altered material derived from pumice, and alternating layers of pumiceous and hemipelagic sediments functioned as a factory of sulphide mineralisation. We infer that anhydrite-rich layers within the hemipelagic sediment forced hydrothermal fluids to flow laterally, controlling precipitation of a sulphide body extending hundreds of meters.

Zoning texture in sphalerite has been described in many studies, although its genesis and ore formation process are poorly constrained. In this investigation, we compare the in situ trace element and isotopic composition of colour-zoned sphalerites from Nayongzhi, South China, to explain the zoning growth process. Petrographic observations identified two broad types of zoned sphalerite, core–rim (CR) and core–mantle–rim (CMR) textures. Each zoned sphalerite displays two or three colour zones, including brown core, light colour bands and/or pale-yellow zones. In situ laser ablation inductively coupled plasma mass spectrometry trace-element analyses show that the three colour zones display variable trace-element compositions. Brown cores exhibit distinctly high Mn, Fe, Co, Ge, Tl and Pb concentrations, whereas pale-yellow and light colour zones have elevated Ga, Cd, Sn, In and Sb concentrations. Copper, Sb, In and Sn show slight variations between pale-yellow and light zones, the latter having higher In and Sn, but lower Cu and Sb abundances. Given the low concentration range of Pb, Ge, Tl, Mn Sb, Cd, etc., the colour of sphalerite is attributed mainly to Fe compositional variation. The δ34S values of sphalerite from Nayongzhi range from +22.3 to +27.9‰, suggesting reduced sulfur was generated by thermochemical sulfate reduction of marine sulfate in ore-hosted strata. Single-crystal colour-zoned sphalerite exhibits intracrystalline δ34S variation (up to 4.3‰), which is attributed to the δ34S composition of H2S in the original fluid. The lack of correlation between trace elements and δ34S values indicates episodic ore solution influxes and mixes with the reduced sulfur-rich fluid derived from the aquifers of the ore-hosted strata, which play a key role in the formation of the zoned Nayongzhi sphalerite. In conclusion, in situ trace element and S isotope studies of zoned sphalerite crystals might provide insight into the ore-forming process of MVT deposits.

The Woumbou–Colomine–Kette district is located in the East Metallogenic Province of the Republic of Cameroon. Northeast- to E-striking splays of the regional Pan-African crustal-scale Sanaga Shear Zone control widespread gold mineralization. Gold occurs within local shear zones developed along granite-gneiss contacts, as well as within the margins of the Pan-African intrusions. Field investigations coupled with mineralogical and textural studies reveal two stages of gold mineralization. Stage 1 led to pyrite, chalcopyrite, sphalerite, pyrrhotite, bismuthinite, tellurobismuthite, galenobismuthite, and native gold deposition with quartz, sericite/muscovite, chlorite, calcite, and ankerite as gangue minerals. Stage 2 included the precipitation of pyrite, hematite, tellurobismuthite, and native gold. A SEM–CL study distinguished the two stages of quartz, as well as an early remnant barren quartz depositional stage. Two fluid inclusion assemblages (FIAs) with four types of fluid inclusions can be observed. The FIA 1 is aqueous-carbonic (±N2±CH4), with carbonate daughter minerals, which is related to stage 1 of the gold mineralization and composed of low salinity (~7.5 wt% NaCl equiv) H2O-CO2-NaCl (type 1), CO2-rich (type 2), and H2O-rich (type 3a) fluid inclusions. The inclusions provide evidence of episodic phase separation, with unmixing at P~2 kbar, T~300 °C, and at a paleodepth of ~7 km. The FIA 2 consists of aqueous (type 3b) fluid inclusions with a salinity of 0.2 to 11.7 wt% NaCl equiv and trapping temperatures between 205 and 245 °C. The δ18Oquartz (+11.0 to +11.7‰), δDfluid inclusions (−46.2 to −40.9‰) and δ13Cfluid inclusions (−4.9 to −4.1‰) for gold-bearing quartz veins suggest a metamorphic source for the ore-forming fluids, although some contribution from the mantle and/or magmatic source(s) cannot be ruled out. The δ34S (+6.5 to +7.0‰) for gold-bearing pyrites suggests a metamorphic source for the sulfur that transported gold and was involved in the precipitation of sulfide minerals. These data are consistent with a mesozonal orogenic gold deposit model for the Woumbou–Colomine–Kette district, which is an important part of the emerging greenfields exploration region for Pan-African orogenic gold and with the more significant targets defined by granite-gneiss contacts along NE- and E-striking shear zones.

The article presents the results of a comparative analysis of fluorite from various mineralization types of the Saf’yanovka massive sulfide deposit in the Central Urals. The predominant green fluorite is intergrown with barite, quartz, and carbonates in hydrothermal colloform and massive pyrite, veinlet–disseminated chalcopyrite–pyrite–sphalerite and pyrite–chalcopyrite ores, as well as in hydrothermally altered rhyolite. In colloform pyrite ore, fluorite together with galena, sphalerite, chalcopyrite, fahlore, and barite fills interstices between crystals. In altered rhyolite, yellow-green fluorite occurs as veins of 1 cm thick, 2–3 cm pockets, and intergrowths with quartz, carbonate, and barite. The rare-earth element (REE) and yttrium concentrations have been determined by ICP-MS. The highest Y content (160 ppm) is measured in fluorite from metasomatic rock; the intermediate Y content (40–130 ppm) is determined in fluorite from pyrite ore, and the lowest one (4–9 ppm) is typical of fluorite from chalcopyrite–pyrite–sphalerite and chalcopyrite ore. The total REE content in fluorite is 70–150 ppm (chalcopyrite–pyrite–sphalerite and chalcopyrite ore), 100–280 ppm in pyrite ore, and reaches 180 ppm in altered rhyolites. The highest REE concentration is caused by the presence of xenotime, goyazite, monazite, barite or apatite inclusions in fluorite. The Tb/La and Tb/Ca ratios suggest that fluorite resulted from hydrothermal processes. The REE distribution patterns with an evident Eu anomaly (Eu/Eu* > 1) show enrichment in LREE. Positive Eu anomalies reflect the high-temperature conditions (≥250°C) during fluorite crystallization. The pressure-corrected (~100–150 bar) temperature of fluorite formation is 190–260°С.

Methods for the preparation of GaAs–CdSe and ZnTe–CdSe solid solutions based on isothermal diffusion of the initial binary compounds (GaAs and CdSe, ZnTe and CdSe) with their main bulk physical and physicochemical properties taken into account are developed. X-ray, microscopic, electron-microscopic, and spectroscopic data enriched the database on multicomponent diamond-like semiconductors. They include the luminescence properties, average sizes, and average numbers of particles. This makes it possible to unambiguously certify solid solutions as of the substitutional type with a cubic sphalerite and wurtzite hexagonal structures depending on the composition. The surface properties (chemical composition and acid-base properties) of the solid solutions and binary components of the systems are studied. When the surfaces are predominantly weakly acidic, there is a relative increase in the basicity with an increase in the amount of CdSe and ZnTe in the GaAs–CdSe and ZnTe–CdSe systems, respectively. The changes in the composition of bulk and surface properties and the correlations between them are found. This simplifies the search for new materials—the primary transducers of sensors.

The Qi191 Au deposit is a newly discovered granite-hosted Au deposit in the Qiyugou Au orefield, located in the southern margin of the North China Craton (NCC). Gold ore bodies are hosted by both the Qi191 hornblende monzogranite and the Taihua Complex and are composed of disseminations and sparse veins. K-feldspar, quartz-sericite, and sericite-chlorite alteration formed outward from the center to the periphery of the mineralized granite. Principal ore minerals include galena, pyrite, and chalcopyrite, with minor sphalerite, hematite, pyrrhotite, gold, famatinite, and hessite. The Qi191 Au deposit formed over four successive stages of hydrothermal mineralization: a quartz stage (I), a quartz-pyrite-galena stage (II), an economic quartz-calcite-galena-pyrite stage (III), and a quartz-calcite stage (IV). The Qi191 hornblende monzogranite yields a SIMS zircon U–Pb age of 131.3 ± 1.0 Ma. Hydrothermal sericite yields a plateau 40Ar–39Ar age of 132.9 ± 1.4 Ma, which is consistent with the zircon U–Pb age, suggesting that the Qi191 Au deposit is generically related to the hornblende monzogranite. Trace element contents and S isotopic compositions of sulfides indicate that metals and S entered the hydrothermal fluid as pulses. The equilibrium temperature of S and the isotopic compositions of S–Pb reflect a magmatic source. Gold mainly precipitated as native gold in a relatively acidic and reducing environment. This work suggests that further exploration for magmatic hydrothermal gold deposits in the Qiyugou and more widely in the southern margin of the NCC should target hornblende monzogranites such as the Qi191 and Qi189 granitoids.

High sensitivity laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) has been utilized for the determination of trace elements in pyrite from the Tharsis VMS deposit, one of the most significant volcanogenic massive sulphide deposits in the southern Iberian Pyrite Belt. The study tracks the content and distribution of trace elements within the different facies of massive sulphides. Widespread and variable enrichment in elements such as Cu, Zn, and Pb in pyrite is interpreted to be due to the presence of nanoinclusions of chalcopyrite, sphalerite, and galena, respectively. A second group of elements, including As, Au, Tl, Mn and Mo, shows significant chemical variations according to the type of mineralization and the textural evolution of the pyrite. This behaviour is thought to be due to the fact that these metals are included in the mineral lattice and its incorporation is controlled by the degree of crystallinity, the temperature, and the redox conditions during crystallization. Early, spongiform and colloform pyrite in the stockwork is enriched in As and Au and interpreted to have formed from a high temperature and low fS2–fO2 fluid. Thallium, Mn, and Mo are enriched in pyrite precipitated at lower temperature and higher oxidation state, i.e., in the exhalative part of the system or in distal facies to the hydrothermal vents. In general, both Co and Ni show an irregular distribution and do not have the sympathetic distribution observed in equivalent studies.

According to developed methods, in the fields of the mutual solubility of initial binary compounds (InP, InSb, and CdS), solid solutions of the InP–CdS and InSb–CdS systems certified as substitutional solid solutions with a cubic sphalerite structure are obtained. Their bulk (crystal-chemical, structural) and surface (the chemical composition of surfaces, acid-base) properties are studied with a set of methods. The relative effect of the initial binary compounds in various manifestations is shown for them. Information about multicomponent diamond-like semiconductors is supplemented. Regularities and correlations for changes in the studied properties of the solid solutions are established. Practical recommendations are given on the use of the obtained materials for the production of sensors based on ammonia microimpurities as well as on applying the established correlations for the cheaper search for new materials.

The southwest Sabzevar basin situated in the Sabzevar zone is considered to be an attractive metallogenic province in Iran that hosts both volcanogenic massive sulfide (VMS) and stratiform manganese deposits. The Nudeh Besshi-type VMS deposit is located in the Lower Late Cretaceous volcano-sedimentary sequence. The ore mineralization in this deposit is hosted in the alkali olivine basalt flow and tuffaceous silty sandstone rocks. The Nudeh VMS deposit consists of 2 million metric tons of Cu-Zn massive sulfide overlying a Cu-Fe-rich stringer. The massive sulfide orebody consists dominantly of pyrite, chalcopyrite, friedrichite, magnetite, and sphalerite, together with minor quartz, chlorite, and sericite. Chloritization, silicification, and sericitization are the main wall-rock alteration types; alteration intensity increases towards the stringer zone. Chloritized footwall rocks extend up to 20 m below the stringer zone. The quartz-bearing stringer veins also contain pyrite, chalcopyrite, magnetite, and bornite. Magnetite crystals from the stringer ores show variable contents of many elements, such as MgO (0.05 wt%), Al2O3 (0.63 wt%), TiO2 (0.07 wt%), V2O3 (0.045 wt%), SiO2 (0.65 wt%), CoO (0.10 wt%), NiO (0.009 wt%), ZnO (0.023 wt%), and CaO (0.03 wt%). The moderate to high V contents are interpreted to result from relatively reduced, seafloor hydrothermal activiy. Compositional variations of magnetite are possibly related to variations in oxygen fugacity, temperature, and water/rock interaction. Within the stringer zone, chlorite 2 (Chl-2) in the vein-veinlets and chlorite 1 (Chl-1) in the chloritized alkali olivine basalt rock are chemically indistinguishable, with 26.92–34.67 wt% FeO and 5.99–14.01 wt% MgO. Chlorite geothermometer studies indicate crystallization formation temperatures of 414 °C (Chl-1) and 303 °C (Chl-2), respectively.