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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.

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.

Bandgap engineering through single-atom site binding on semiconducting photocatalyst can boost the intrinsic activity, selectivity, carrier separation, and electron transport. Here, we report a mixed-valence Ag(0) and Ag(I) single atoms co-decorated semiconducting chalcopyrite quantum dots (Ag/CuFeS2 QDs) photocatalyst. It demonstrates efficient photocatalytic performances for specific organic dye (rhodamine B, denoted as RhB) as well as inorganic dye (Cr(VI)) removal in water under natural sunlight irradiation. The RhB degradation and Cr(VI) removal efficiencies by Ag/CuFeS2 QDs were 3.55 and 6.75 times higher than those of the naked CuFeS2 QDs at their optimal pH conditions, respectively. Besides, in a mixture of RhB and Cr(VI) solution under neutral condition, the removal ratio has been elevated from 30.2% to 79.4% for Cr(VI), and from 95.2% to 97.3% for RhB degradation by using Ag/CuFeS2 QDs after 2 h sunlight illumination. The intrinsic mechanism for the photocatalytic performance improvement is attributed to the narrow bandgap of the single-atomic Ag(I) anchored CuFeS2 QDs, which engineers the electronic structure as well as expands the optical light response range. Significantly, the highly active Ag(0)/CuFeS2 and Ag(I)/CuFeS2 effectively improve the separation efficiency of the carriers, thus enhancing the photocatalytic performances. This work presents a highly efficient single atom/QDs photocatalyst, constructed through bandgap engineering via mixed-valence single noble metal atoms binding on semiconducting QDs. It paves the way for developing high-efficiency single-atom photocatalysts for complex pollutions removal in dyeing wastewater environment.

Ceramic ball (CB) and cast iron ball (CIB) media were used in the grinding of chalcopyrite and pyrite (1:1) to investigate the influence of grinding media on flotation separation. The selectivity indexe values were 2.65 (CB) and 1.58 (CIB) under the optimal conditions. In the CB system, the concentrations of Cu2+, SO42−, dissolved oxygen, and pH in the slurry were slightly higher. The root-mean-square roughness (Rq) values of the CB and CIB systems ground products were 9.02 nm and 74.80 nm, respectively. Moreover, a large amount of FeOOH was formed on the surface of the CIB ground products owing to the electrochemical interaction between the minerals and the media. Density functional theory (DFT) calculations indicated that FeOOH was adsorbed preferentially on the surfaces of chalcopyrite and pyrite, thus severely hindering the adsorption of butyl xanthate. Therefore, the CB medium is beneficial for enhancing the flotation performance of chalcopyrite and pyrite.

Research subject. The mineral compositions of titanomagnetitic (apatite, titanomagnetite) and copper-titanomagnetitic (bornite, chalcopyrite, apatite, titanomagnetite) ores of the Volkovskoe Cu-Fe-Ti-V deposit (Middle Urals, Russia).Methods. The research was carried out using a Jeol JSM-6390LV scanning electron microscope and X-ray spectral microanalyzers JXA-5 (Jeol) at the Geoanalitik Collective Use Center of the IGG UB RAS. Results and conclusions.Native gold (with ≤ 0.3 wt % Pd, 0.2–0.4 wt % Cu; fneness 800–914 ‰), tellurides of Pd, Au and Ag (merenskyite, keithconnite, sylvanite, hessite) and Pt arsenide (sperrylite) were found in the copper-titanomagnetitic ores. For the frst time, two generations of native gold (fneness 1000 and 850–860 ‰) and palladium telluride (keithconnite Pd3-xTe) were detected in titanomagnetitic ores. The sequence of ore mineral formation and the features of their genesis were revealed. Native gold (fneness 1000‰) in the form of microinclusions in titanomagnetite was attributed to the magmatic stage. Noble metal minerals, intergrown with copper sulfdes (bornite, chalcopyrite, digenite) and associated with late hydroxyl-bearing minerals (amphibole, epidote, chlorite), are superimposed in relation to the magmatic minerals (pyroxene, plagioclase, hornblende, apatite, titanomagnetite, ilmenite, etc.) of these ores. Merenskyite, sperrylite, high fneness gold (800–914 ‰), as well as carrolite, cobaltite, copper-cobalt telluride and bismuth tellurium-selenide kawazulite Вi2Te2Se are syngenetic with copper sulfdes. The Au-Ag tellurides were deposited later than these minerals. It is shown that the high fugacity of tellurium, which binds Pd, Au, and Ag into tellurides, prevents the occurrence of native gold containing high concentrations of palladium and silver.

The paper proposes a method for quick estimation of the average floatability of minerals according to the kinetic experiment, without finding the flotation spectrum where first moments of distribution are calculated by the coefficients of the polynomial approximation of the kinetic curve in the logarithmic form. An example of copper-nickel ore demonstrated that this method is effective in the multiparameter problem of comparative assessment of reagents. The ten parameters assessed included the average floatability of target minerals (chalcopyrite and pentlandite), pyrrhotite and rock; flotation selectivity coefficients of target minerals relative to pyrrhotite and rock; levels of copper and nickel losses with bulk flotation tailings. Interdependencies of parameters were visualized using diagrams showing the effect of flotation reagents on the groups of parameters: average floatability, selectivity coefficients, metal losses and selectivity relative to rock. The influence of butyl xanthate, aerofloat, diesel fuel, as well as gangue depressants – carboxymethyl cellulose (CMC) and acidified water glass (with a total consumption of collectors, diesel fuel, acidified water glass and CMC of 130 g/t, 5–10 g/t, 200 g/t, and 500 g/t, respectively) on the estimated parameters under collective flotation conditions was determined. It was found that the addition of aerofloat and diesel fuel to the main reagent collector – xanthate – increases the flotation selectivity of pentlandite and chalcopyrite relative to pyrrhotite and rock-forming component. The introduction of acidified water glass into the reagent scheme increases the flotation selectivity of nickel and copper sulfides relative to the rock. CMC additives impair the selectivity of copper flotation. The quantitative effects of each individual parameter were taken into account in the integral rating assessment of the prospects of using reagent combinations for copper-nickel ore by a set of ten parameters. The method proposed can be further used for the mass comparative evaluation of flotation reagents.

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.

The Tiegelongnan porphyry-epithermal deposit (2089 Mt @ 0.53% Cu, 0.08 g/t Au) is host to a large variety of Cu-sulfide minerals, mainly chalcopyrite, bornite, covellite, digenite, enargite, and tennantite. We used LA-ICP-MS to investigate the trace element geochemistry of the Tiegelongnan Cu-sulfides, as well as pyrite, to understand the correlation between sulfides and trace elements, gold in particular, in the porphyry and epithermal systems. Porphyry mineralization consists of stage 1 chalcopyrite-pyrite ± molybdenite, stage 2 chalcopyrite-bornite, and stage 3 covellite. Epithermal sulfides form stage 4 pyrite-alunite, stage 5 digenite-bornite-chalcopyrite, and stage 6 enargite-tennantite ± tetrahedrite. Stage 2 chalcopyrite (S2 Ccp, median = 9.7 ppm Au) is the primary porphyry Au host, and stage 6 tennantite in alunite veins (S6 Tnt-s, median = 98.0 ppm Au) is the major epithermal Au host. These Au-rich sulfides formed under higher oxidation conditions, suggesting that a high oxidation state favors the incorporation of Au in Cu-sulfides. Gold contents in coeval chalcopyrite and bornite are positively correlated to temperature, and Au is enriched in chalcopyrite over bornite at low temperatures (

Appreciable amount of copper mineralisation dominated by chalcopyrite along with incidence of uranium within the Mayurbhanj granite batholith in Kesharpur-Madansahi-Dudhiasol sector has been established through preliminary exploration (UNFC-G3). Chalcopyrite-pyrite-pyrrhotite assemblages along with minor pentlandite seems to be preferably controlled through secondary structural shear fabric and vein selvages along the contact zones of granite and country rocks viz. hornblende biotite schist and metabasics. Hydrothermal alteration is notably marked by potassic, propyllitic and phyllic zones besides wide chloritisation and silicification in close proximity and within mineralised zone. Three potential prospects of significant copper mineralisation in terms of thickness and grade have been brought out at Kesharpur, Madansahi and Dudhiasol. These prospects show a linear lensoidal synformal disposition of the ore body trending NE-SW in eastern part to E-W in central part and NW-SE in the western part with moderate to steep northerly dipping. Out of these three prospects, Madansahi is quite promising where thickness of copper lodes varying from 2.00 m to 18.35 m and grade varies from 0.20% Cu to 1.76% with maximum nickel concentration of up to 0.13% Occurrence of copper mineralisation along with nickel concentration and anomalous uranium values up to 0.045% U3O8 is a significant achievement in establishing polymetallic mineralisation and augmenting the mineral resources in eastern India.

This article investigates the effect of material size on the efficiency of flotation concentration of gold-copperarsenic ores of the Taror deposit (Republic of Tajikistan) and studies the dependence of gold recovery on the duration of the process with the purpose of developing an alternative technological scheme for processing this ore type. According to X-ray phase analysis, Taror ore samples consist of rock-forming minerals by 92%. Ore mineralization is represented by sulphide minerals, mainly arsenopyrite, chalcopyrite and pyrite, in the total amount of 8%. Ore-forming elements include iron, sulphur, arsenic and copper with the mass fraction of 6.02%, 3.26%, 1.52% and 0.82%, respectively. Gold and silver are contained in the ore in the amount of 7.35 g/t and 20.28 g/t, respectively. The oxidation state of the ore calculated by iron comprises 51.3%. According to this indicator, this ore type can be distinguished as mixed, close to the primary type. According to the conducted chemical phase analysis of gold, this ore type belongs to the category of refractory ores. Flotation concentration experiments showed that grinding the original ore to a size of 95%–71 microns increases the recovery of gold in the concentrate by 10%, compared to grinding to a particle size of 80%–71 microns. The effect of the flotation process duration on gold recovery was also studied. To achieve the maximum gold recovery in the flotation concentrate, the duration of the main flotation and control flotation should be taken equal to 14 and 12 minutes, respectively. As a result of the experiments, a relatively simple technological solution was proposed for flotation concentration of the Taror ore, which includes the main, control and cleaning stages of flotation.

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)

ZJ 201 (modified starch) is a non-toxic, odorless, and biodegradable polymeric depressant, which selectively depressed galena in batch flotation tests while chalcopyrite was not significantly affected. In a plant trial, copper-lead separation was successful for the first time without using dichromate. Moreover, the plant process could be changed to sequential Cu-Pb flotation using ZJ 201 for higher grade lead concentrate. A copper concentrate was obtained with a Cu grade of 24.91% and a Pb grade of 5.11%, which recovered 76.6% of the copper from the original ore; a lead concentrate was also obtained with a Pb grade of 21.90% and a Cu grade of 5.31%, which recovered 52.6% of the lead. In addition to the effective copper-lead separation observed in the plant trial, another improvement observed is that gold was recovered mostly in copper concentrate, which could be sold for higher prices. Au grade reached 230.64 g/t, and its recovery reached 65.8% in the copper concentrate. Au grade in lead concentrate was only 18.90 g/t.

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 effects of halophilic bacteria (Halobacillus sp. and Marinobacter sp.) on pyrite and chalcopyrite surface oxidation in artificial seawater are studied by electrochemical impedance spectroscopy (EIS) in conjunction with X-ray diffraction (XRD) and cyclic voltammetry analysis (CV), in order to explain the influence of these microorganisms on the minerals floatability. EIS analyses on pyrite electrodes suggest that biomaterial from both bacteria adheres to the mineral surface, which is reinforced by CV experiments as capacitive currents are promoted by both bacteria. Additionally, XRD analyses of pyrite samples after immersion in artificial seawater with and without bacteria indicate the formation of hematite on the mineral surface in the presence of Halobacillus sp., which together with the adherence of biomaterial could promote the depression of pyrite during flotation. On the other hand, EIS and CV analyses on chalcopyrite electrodes suggest that the adherence of Halobacillus sp. and Marinobacter sp. to the surface of the mineral have no significant effects on the kinetics of the chalcopyrite oxidation processes. These results together with XRD analyses of the chalcopyrite samples after immersion in artificial seawater with and without bacteria suggest that superficial sulphur might have a stronger influence on chalcopyrite flotability than the presence of bacteria.

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.

Copper slags are solid by-products formed during the copper production process by pyrometallurgical method from sulfide copper ores. These slags usually contain significant quantities of valuable metals, such as cobalt, nickel, zinc and copper, in different forms. Extraction characteristics of Cu, Co, Zn, and Fe from Kure historical copper slag (KHS) by oxidative pressure leaching were investigated with sulfuric acid lixivant in this study. The phase composition of the studied slag was identified by the use of a combination of methods, including a mineral liberation analyzer (MLA), a scanning electron microscope coupled with an energy-dispersive spectrometer (SEM-EDS), and X-ray powder diffraction (XRD). Bornite, chalcopyrite, cuprospinel, brochantite, chalcocite, and metallic Cu are identified as copper-containing minerals. The samples used in leach tests contained averages of 0.84% Cu, 0.34% Co, 0.23% Zn, 2.90% Al, 0.70% Ca, 1.30% S, and 42.80% Fe. The factors affecting the performance and efficiency of the pressure leaching process, such as acid concentration, leaching time, solid/liquid ratio, oxygen partial pressure, particle size, and temperature, were investigated separately. It was found that metal extraction increased with temperature and sulfuric acid concentration. However, high acid concentrations led to gel formation that caused filtration problems. Under optimum conditions, the extraction efficiencies of cobalt, copper, and zinc from KHS were 96.82, 92.85, and 93.44%, respectively, while the extraction of iron was only 0.3%.

For the first time, from the standpoint of magmatism and subsequent hydrothermal–metasomatic alteration, sulfide and platinum-metal mineral assemblages of rocks of ore-bearing intrusions of the Khudolaz Complex have been characterized. Four types of assemblages have been identified: (1) pentlandite–chalcopyrite–pyrrhotite in the form of drop-shaped and interstitial disseminations with inclusions of sperrylite, moncheite, michenerite, merenskyite, froodite; (2) complex amoebalike inclusions with the composition pyrite ± pyrrhotite–chalcopyrite–violarite ± pentlandite with inclusions of Sb–michenerite, sudburyite, and borovskite; (3) newly formed pyrite–chalcopyrite veins and patches in intensely metasomatized rocks; (4) additionally-formed euhedral pyrite disseminations in metasomatites along zones intersected by dolerite dikes. The formation of these sulfide–platinum-metal assemblages occurred in three stages: (1) magmatic and late magmatic (type 1), 2) hydrothermal–early medium temperature and late low-temperature (types 2, 3), (3) repeated hydrothermal–low–medium temperature (type 4). It is shown that the crystallization of sulfide minerals occurred in a wide temperature range (about 1000–200°C). PGE minerals separated at the late magmatic stage during cooling of a highly fractionated sulfide or immiscible chalcogenide melt and during decomposition of sulfide solid solutions (T ~ 650–300°C). At the early hydrothermal stage (T ~ 300–250°C), pyrrhotite was replaced by pyrite; pentlandite, by violarite; a significant amount of Ni and Co from primary sulfides was inherited by secondary sulfides. Primary chalcopyrite was mainly replaced by silicates (chlorite, amphibole, etc.). It is suggested that the antimony minerals of Pd (including high-antimony michenerite with Sb up to 0.46 apfu) could have crystallized from an Sb-enriched hydrothermal fluid. Host rocks could have been an additional source of antimony in the fluid. At the late hydrothermal stage (T < 200°C), significant dissolution of primary sulfide and platinum-metal phases occurred with redeposition in the upper parts of massifs and in host rocks. The recurring hydrothermal process (T ≤ 200°C) was associated with emplacement of dikes of the Ulugurtau complex and new redeposition of sulfides along zones of fluid action.

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.

As ore grades constantly decline, more copper tailings, which still contain a considerable amount of unrecovered copper, are expected to be produced as a byproduct of froth flotation. This research reveals the occurrence mechanism of copper minerals in typical copper sulfide tailings using quantitative mineral liberation analysis (MLA) integrated with scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). A comprehensive mineralogical characterization was carried out, and the results showed that almost all copper minerals were highly disseminated within coarse gangue particles, except for 9.2wt% chalcopyrite that occurred in the 160–180 µm size fraction. The predominant copper-bearing mineral was chalcopyrite, which was closely intergrown with orthoclase and muscovite rather than quartz. The flotation tailings sample still contained 3.28wt% liberated chalcopyrite and 3.13wt% liberated bornite because of their extremely fine granularity. The SEM-EDS analysis further demonstrated that copper minerals mainly occurred as fine dispersed and fully enclosed structures in gangue minerals. The information obtained from this research could offer useful references for recovering residual copper from flotation tailings.

The newly discovered East Longjing-2 hydrothermal field (ELHF-2) is located on the Dragon Horn oceanic core complex of the ultraslow-spreading Southwest Indian Ridge, approximately 12 km from the ridge axis. This study measured the chemical compositions of pyrite from ELHF-2 using a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to investigate the genesis of the field. Three generations of pyrite were classified, and found that: Py1 and Py2, rich in V, Mn, U, and Se, occur in altered basalt debris and the silica alteration matrix, respectively. Py3 was mainly intergrown with chalcopyrite in quartz veins and had higher Cu, In, Ag, Sb, and Au contents than Py1 and Py2. Some elements, such as Au, Se, and Pb, are likely presented as direct substitution with Fe2+ in pyrite, while Cu, Zn, Co, Ni, and Ag probably occur both as direct substitution with Fe and as distributed micro- to nanoparticle-sized sulfides. Meanwhile, the occurrence of V, Mn, and U is likely presented as oxide inclusions. Trace element geochemistry suggested that the pyrite was formed under high-temperature conditions, and the ore forming elements were likely derived from ultramafic rocks. In addition, Py1 and Py2 were formed under higher water/rock ratio and higher temperature conditions, with more seawater involvement compared with Py3. The formation of ELHF-2 was probably driven by exothermic serpentinization reactions with an additional magmatic heat. This study shows that high-temperature hydrothermal circulation driven by magmatic activity can be developed on distal rift flank areas of magma-starved ultraslow-spreading ridges.

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 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.

Replacement of pyrite by copper-bearing sulfides is widespread in mineral deposits, with zonation of chalcocite, bornite, and chalcopyrite being a common result of this process. Copper occurs predominantly as Cu(I) in hydrothermal fluids, but the mechanistic details of reactions between pyrite and aqueous Cu(I) and their relevance to the zonation of Cu sulfides in hydrothermal deposits remain poorly understood, because of a lack of relevant experimental constraints. In this study, we investigated the reactions between pyrite and aqueous Cu(I) chloride solutions over a wide range of physicochemical conditions (100–250 °C; pH = 1–8; saturated vapor pressure). The experimental results show that Cu-bearing sulfides form at temperatures of >150 °C, and that pH exerts an important control on the mineralogy of the reaction products. In strongly acidic conditions (pH = 1.1), pyrite dissolution occurs; in acidic-to-neutral conditions (pH = 3.0–6.0), chalcopyrite and bornite are the main products; in weakly alkaline conditions (pH = 8.2), the replacement products are chalcocite and bornite. Chalcopyrite, bornite, and chalcocite generally occur in a zoned sequence outward from the pyrite reaction front to the bulk solution, and the replacement of pyrite by chalcopyrite is heterogeneous. In situ Raman observation and S isotope analyses suggest that pyrite replacement by chalcopyrite is a redox-coupled dissolution–precipitation reaction, with the oxidative dissolution of pyrite to form sulfate, generating the electrons that maintain the reductive replacement of pyrite by chalcopyrite. The sites of oxidative dissolution and reductive replacement can be spatially separated, but coupled by electron transfer. By contrast, the further replacement of chalcopyrite by bornite and chalcocite does not involve the oxidative dissolution of sulfur, but release of iron and H+, which could be promoted at higher pH. Notably, when the zonation of sulfides is established in a hydrothermal experiment of pyrite replacement by Cu(I) solution, gradients of H2S (or HS–), Cu(I), and Fe(II) are developed between the pyrite reaction front and bulk solution via diffusion through interstitial pore space. As such, the inner zones of chalcopyrite and bornite are not in equilibrium with the bulk solution as confirmed by thermodynamic calculations. The results imply that the zonation of Cu-bearing sulfides in mineral deposits records heterogeneous chemical environments, from the mineral interface- to the ore deposit-scale during dynamic mineralization processes.

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.

Copper-sulfides within carbonatites and phoscorites of the Phalaborwa Igneous Complex, South Africa, have been investigated since the middle of the 20th Century. However, aspects of ore formation have remained unclear. This study examines the mechanisms involved in Cu-sulfide mineralisation by micro-focus X-ray computed tomography as applied to sulfide-rich drill core samples. Several texturally distinct assemblages of magmatic sulfides can be identified, including: (1)

Brambang is one of the porphyry copper-gold prospects/deposits situated along eastern Sunda arc. This study is aimed to understand geological framework, alteration geochemistry and ore fluid characteristics of the prospect. Fieldworks and various laboratory analyses were performed including petrography, ore microscopy, rock geochemistry, chlorite chemistry and fluid inclusion microthermometry. The prospect is composed of andesitic tuff and diorite which are intruded by tonalite porphyries. Tonalite porphyries are interpreted as ore mineralisation-bearing intrusion. Various hydrothermal alterations are identified including potassic, phyllic, propylitic, advanced argillic and argillic types. Ore mineralisation is characterized by magnetite and copper sulfides such as bornite and chalcopyrite. Potassic alteration is typified by secondary biotite, and associated with ore mineralisation. Mass balance calculation indicates SiO2, Fe2O3, K2O, Cu and Au are added during potassic alteration process. Ore forming fluid is dominated by magmatic fluid at high temperature (450-600ºC) and high salinity (60-70 wt. % NaCl eq.). Hydrothermal fluid was diluted by meteoric water incursion at low-moderate temperature of 150-400ºC and salinity of 0.5-7 wt. % NaCl eq.

The limited availability of conventional water resources and inefficient water management has resulted in seawater use in the flotation process of copper sulfide ores at several concentrator plants...

Chalcopyrite (CuFeS2) is the most refractory copper mineral when treated in conventional sulfate media leaching systems. This is the first study to examine the use of a dimethyl sulfoxide (CH3SOCH3, DMSO) solution containing copper chloride (CuCl2) for the leaching of chalcopyrite. Leaching experiments for a copper concentrate composed mainly of chalcopyrite were conducted at ambient pressure at 313–413 K. The leaching fractions of Cu, Fe, S, Au, and As were investigated. It was found that 90% of the Cu was extracted in 2 h, and 94% was extracted in 4 h at 373 K, which is competitive with other conventional processes. A DMSO solution containing CuCl2 could selectively dissolve the valuable metals Cu and Au from chalcopyrite, but leave minerals with little economic value such as pyrite (FeS2) and As in the residue. Chalcopyrite is oxidized by cupric ion in proportion to the stoichiometric ratio of Cu in the concentrate to the initial cupric ion in the DMSO solution, which is enhanced by the presence of oxygen below 373 K.

The Abra deposit, a large lead-silver-copper–gold polymetallic deposit in Western Australia, is located at the eastern of the metallogenic belt of the Jillawarra basin in the Bangemall basin. The 4th to the 6th rock section of the Irrigully Group of Edmund Series are the principal ore-host strata, composed mainly of sandstone and fine sandstone. The orebody in Abra can be classified into two types as upper layer-like lead-silver and lower veins or netvein copper–gold. The metal minerals are mainly galena, chalcopyrite, and pyrite, while the gangue minerals are mainly quartz, dolomite, and barite. Both Re-Os isotopic age of the pyrite (1329.5 ± 98 Ma) with the initial (187Os/188Os) = 5.0 ± 3.8 and Pb isotopic compositions (206Pb/204Pb = 15.914–15.967, 207Pb/204Pb = 15.425–15.454, 208Pb/204Pb = 35.584–35.667) suggests that the metal minerals were sourced from the wall-rocks. δDV-SMOW values of quartz range from -35‰ to -17‰ whereas δ18OV-SMOW value range from 12‰ to 16‰ which indicates that the ore-forming fluids of Abra were medium–low temperature and medium–low salinity, and were mainly metamorphic water and secondary atmospheric precipitation. When the medium–low temperature ore-forming fluids are mixed with oxidizing reducing fluids carrying a large number of metal substances, a large number of ore-forming substances will be precipitated when the physical and chemical conditions change, thus it can be considered that the Abra deposit is a medium–low temperature hydrothermal polymetallic deposit.

Valleriite is of interest as a mineral source of basic and precious metals and as an unusual material composed of two-dimensional (2D) Fe-Cu sulfide and magnesium hydroxide layers, whose characteristics are still very poorly understood. Here, the mineral samples of two types with about 50% of valleriites from Noril'sk ore provenance, Russia, were examined using Cu K- and Fe K-edge X-ray absorption fine structure (XAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), Fe-57 Mossbauer spectroscopy, and magnetic measurements. The Cu K X-ray absorption near-edge structures (XANES) spectra resemble those of chalcopyrite, however, with a higher electron density at Cu+ centers and essentially differ from those of bornite Cu5FeS4; the Fe K-edge was less informative because of accompanying oxidized Fe- containing phases. The post-edge XANES and extended XAFS (EXAFS) analysis reveal differences in the bond lengths, e.g., additional metal-metal distances in valleriites as compared with chalcopyrite. The XPS spectra confirmed the Cu+ and Fe3+ state in the sulfide sheets and suggest that they are in electron equilibrium with (Mg, Al) hydroxide layers. Mossbauer spectra measured at room temperature comprise central doublets of paramagnetic Fe3+, which decreased at 78 K and almost disappeared at 4.2 K, producing a series of hyperfine Zeeman sextets due to internal magnetic fields arising in valleriites. Magnetic measurements do not reveal antiferromagnetic transitions known for bornite. The specific structure and properties of valleriite are discussed in particular as a platform for composites of the 2D transition metal sulfide and hydroxide(mono)layers stacked by the electrical charges, promising for a variety of applications.

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.

Mineral separation by flotation is a water-intensive process; thus, recycling and reusing the process-water have essential environmental and financial impacts for ore beneficiation plants. The recycled water contains different ions, which affect flotation responses. Several investigations focused on the effects of monovalent and divalent ion contents of the recycled water and seawaters on the flotation recovery. However, there is a gap in exploring the influence of trivalent ions on the metallurgical responses of sulfide flotation. This work is going to fill this gap by exploring and comparing the effect of Na+, Mg2+, and Al3+ on the chalcopyrite and pyrite's flotation responses. Different flotation experiments and surface analyses were considered to assess and compare these multivalent cations' impacts on the flotation responses. Outcomes indicated that compared to Na+ and Mg2+, Al3+ could significantly change both minerals' surface properties, relatively improved pyrite's floatability, and decreased the chalcopyrite recovery. Adsorption of Al(OH)3(s) on the minerals surface and the collector - Al(OH)3(s) aggregate could explain these variations.

Surface oxidation has a significant influence on sulfides flotation. However, there is a little literature about the effect of surface oxidation in the flotation of mixed copper‑nickel sulfide (Cu Ni sulfide, mainly composed of pentlandite, chalcopyrite, pyrite and pyrrhotite). In this work, the effect of surface oxidation on the Cu Ni sulfide flotation was studied. Flotation results showed the surface oxidation had a stronger depression effect on Cu Ni sulfide flotation than that on the flotation of single pyrite and chalcopyrite mineral samples. XPS analysis results showed that the hydrophilic products sulfate and Fe/Ni oxide/hydroxide were generated on the oxidized Cu Ni sulfide surface, whereas no Cu oxide/hydroxide was found, indicating the occurrence of galvanic interaction, which might cause the stronger depression of oxidation on Cu Ni sulfide flotation. However, after the pretreatment of ultrasonic cleaning in HCl solution, the sulfate and iron hydroxide/oxide on Cu Ni sulfide surface decreased significantly, and then Cu Ni sulfide floatability was regained to some extent. Interestingly, adsorption results exhibited that the adsorption amounts of PBX on Cu Ni sulfide surface basically unchanged before and after oxidation, which might be caused by that chalcopyrite and pyrite were protected from oxidation as the cathode minerals in the galvanic interaction.

Manipulation of material composition can often induce unprecedented optoelectronic changes in semiconductor nanocrystals (NCs). Here, we demonstrate that bornite-phase copper iron sulfide (Cu5FeS4)...

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.

The reduction of oxidized sulfur is essential in porphyry copper deposits whose mineralization predominantly comprises copper sulfides, whereas their source magmas are oxidized with most of their sulfur as SO42− and with exsolved fluids having SO2>>H2S. To estimate the redox state of sulfur, we examined drill cores that intersect potassic and unaltered intrusive rocks in the deeper levels of the Grasberg porphyry copper-gold deposit. Magmatic oxybarometers such as the amphibole-titanite-magnetite-quartz assemblage, anhydrite, and amphibole consistently show that Grasberg ore-forming magmas were oxidized with fO2 > FMQ+3. Initial hydrothermal events formed sulfide-free, anhydrite-rich K-feldspar, and biotite alteration, followed by successive vein stages of (1) magnetite, (2) biotite, (3) quartz, (4) anhydrite-chalcopyrite, (5) chalcopyrite ± sericite selvages, and (6) pyrite-chalcopyrite-quartz + sericite selvages. The δ34S values of sulfide-sulfate mineral pairs indicate SO2-derived SO42− and H2S in SO42−/H2S molar proportions of ~ 4:1 to ~ 3:1 at > 550 °C. The hydrothermal fluid then likely followed a rock-buffered trajectory and became more reduced at

The Aqishan-Yamansu metallogenic belt (AYMB) in East Tianshan hosts abundant submarine volcanic-hosted iron deposits. Although there is agreement with the magmatic source of the ore-forming materials and the role of hydrothermal replacement in iron ore formation, the mineralization processes of these iron deposits remain uncertain. Three ore types are identified on the basis of the geological occurrences of minerals and the sequence of mineral in ores. The type I ores are characterized by magnetite, diopside, amphibole with a few pyrite, and chalcopyrite. The type II ores are mainly composed of magnetite, garnet, chlorite with a few pyrite, while the type III ores are mainly composed of magnetite, quartz, calcite with a few pyrite. In order to constrain the mineralization processes of these ore types, we performed iron isotopes and trace element compositions of magnetite from three typical iron deposits (Yamansu, Duotoushan and Luotuofeng). Trace element and Fe isotope investigations of the three ore types reveal two major groups. The group I consists of analyses of the type I and II ores, with both showing a narrow range of positive δ56Fe values (+0.08‰ to +0.22‰ for type I ores and +0.15‰ to +0.22‰ for type II ores) and plotting in the range of the ortho-magmatic field. In contrast, the group 2 is composed merely of the type III ores, showing a wider range of negative δ56Fe values (-0.49‰ to -0.01‰), which is similar to the features of Fe-skarn magnetite. As shown in the binary diagrams of magnetite trace elements and a fractionation of the Fe isotopes, different ore types were likely produced during gradually changing ore-forming stages from magmatic to hydrothermal. Collectively, the submarine volcanic-hosted iron deposits in the East Tianshan are likely the results of a continuous magmatic-hydrothermal mineralization process.

Uranium deposit at Gogi area is located along the E-W Gundahalli-Gogi-Kurlegere (GK) fault, in the brecciated impure limestone of Shahabad Formation of the Bhima Group of sediments and the basement granite in the central part of the Meso-Neoproterozoic Bhima basin. Uranium mineralisation is associated mainly with sulphide bearing minerals and secondary calcite. Ore microscopic studies indicate that among the sulphide minerals pyrite is predominant (about 98%) with subordinate amounts of chalcopyrite, chalcocite, marcasite, arsenopyrite and galena. Megascopically, three different varieties of pyrite viz., euhedral, lumpy and vein types are identified in the limestone and siltstone. Ore microscopic studies reveal that vein type pyrite and lumpy pyrite are fractured and crushed. Euhedral pyrite is idiomorphic and devoid of any fractures. The pyrite samples were analysed for δ34S sulphur isotopes. The δ34S values show a wide range from −30.51 to +20.77‰ (Canyon Diablo Troilite, CDT). δ34S values of pyrite can be classified into three groups depending on the values. High values of +17.73 to +20.77 ‰ (CDT) of euhedral pyrite (Py-I) indicate sedimentary pyrite formed due to bacterial reduction of sea water sulphate in relatively closed system, while pyrite (Py-II) having negative values of δ34S imply bacterial reduction of sea water sulphate in open system. The third group (Py-III) of pyrite have δ34S values of −0.51‰ (CDT) and 7.38‰ (CDT), indicating their magmatic/hydrothermal origin. Sulphides in the deformed sediments acted as reducing agent for uranium precipitation.

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.

The goal of the present work was to study the dependence of the rate of copper and zinc bioleaching from an arsenic-containing copper-zinc concentrate containing 16% Cu, 5.3% Zn, and 1.36% As, on the temperature and the presence of an organic carbon source (yeast extract) in the medium. The main minerals of the concentrate were chalcopyrite (CuFeS2), tennantite (Cu12As4S13), sphalerite (ZnS), and pyrite (FeS2). A mixed culture of moderately thermophilic acidophilic microorganisms oxidizing sulfur and ferrous iron, which was used in the work, consisted of the strains Acidithiobacillus caldus MBC-1, Sulfobacillus thermosulfidooxidans SH-1, and Acidiplasma sp. MBA-1. The experiments were carried out in flasks with 100 mL of mineral medium and 2 g of the concentrate on a rotary shaker for 30 days at temperatures from 40 to 60°C. It was shown that the leaching rate of copper depended both on temperature and on the presence of yeast extract. Copper leaching rate increased with increasing temperature, while zinc leaching was less dependent on the temperature. In the presence of an organic carbon source in the medium, both copper and zinc were actively leached at high temperatures (55 and 60°C), while in experiments with a medium without yeast extract, the activity of non-ferrous metals leaching from the concentrate at these temperatures was much lower. At the same time, at temperatures of 40–50°C, leaching activity was less dependent on the presence of the organic carbon source in the medium.

This study investigated the dissolution behavior of metals from chalcopyrite concentrate in a pressure reactor system in the presence of hydrogen peroxide by oxalic acid leaching. The fact that the compounds formed by copper and iron with oxalic acid had different dissolution coefficients showed that metals could be selectively extracted based on the leaching temperature. The effects of various leaching parameters on metal extraction in the autoclave system were investigated at different H2O2 concentrations (1-5 M), H2C2O4 concentrations (25-125 g/L), leaching temperatures (318-443 K) and leaching times (15-180 min). While iron and copper extraction as a result of 180 min of leaching with 5 M H2O2, 318 K and 100 g/L H2C2O4 was respectively 90.6% and 1.73%, 88.5% of copper and 2.11% of iron could be extracted as a result of 180 min of leaching with 3 M H2O2, 443 K and 100 g/L H2C2O4. The reversal of the copper and iron extraction dissolution behavior started after the leaching temperature of 378 K. In the XRD analysis of leach residues obtained at low leaching temperatures, CuC2O4 peaks were dominant, while at high temperature conditions, Fe2O3 peaks were dominant. (c) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Potassium butyl xanthate adsorption at galena and chalcopyrite is characterized using the methods of atomic force microscopy and spectroscopy. It is found that layers generated on galena and chalcopyrite surface as a result of agitation in distilled water and interaction with potassium butyl xanthate solution have cardinally different morphology. Observations over adsorption of the reagent in liquid phase reveal different mechanisms of the reagent coating growth on these minerals.

Acid and Metalliferous Drainage (AMD) is recognised as serious environmental problem in the mining industry. This is because environmental issue of AMD poses serious threat to water quality, vegetation cover and social licence of the mining operations. AMD occurs when reactive sulphide bearing materials are exposed to oxidising conditions. It has now become imperative for some mining companies to test sulphide bearing minerals for their AMD potential before major mining excavations are done. This work determines the AMD potential of fifty (50) waste rock samples from a Mine using Acid Base Accounting (ABA) techniques. Mineralogical studies on the sample indicated that the major sulphide mineral assemblages present were pyrite, arsenopyrite and chalcopyrite. Paste pH showed that 20% of the samples had undergone weathering and as such AMD generation had already started. Approximately 22% of the sample had conductivity levels between 1000 to 10,000 µS/cm and this shows a typical AMD chemical characteristic of high salinity. Acid Base Accounting showed that 32% of the samples were acid generating. Exactly 16% were non-acid forming and 52% were uncertain. The analysis showed that the potential for AMD generation exists for the waste rock material and can affect the local environment, specifically water quality if preventive measures are not taken. Keywords: Sulphide, Waste Rock, Acid Base Accounting, Paste pH, Conductivity

Changes in the weight of copper concentrate from oxidation and a decrease in copper content create economic losses. Mining plants having problems with increasing overall weight of the copper concentrate and reduction of the copper composition after a certain period of transport and handling. Trivalent iron, one of the main oxidizing factors of the copper concentrate, is a strong oxidizer that oxidized copper sulfide minerals as well as other minerals in the concentrate, which is formed by the oxidation of pyrite. Generally, mass change can occur during electron transition and phase transfer. Therefore, the chemical mechanism, oxidation process, and content alteration of the main components in copper concentrate were studied in this study in order to solve and define those problems. To study the real condition of the copper concentrate oxidation, the oxidation process of the copper concentrate was studied under 3 conditions such as in the shadow, in the sun, and the storage. Mongolian National Standard and International standards (MNS2078:1984, ISO 10258:2018) and XRD, AAS, ICP analysis were used to study the main components of the copper concentrate. By the study on the oxidation of copper concentrate at the mine site, copper was decreased by 0.77-0.85%, and iron was reduced by 0.30-0.64%. As a result of the oxidation study of concentrate that is kept in the mining site, temperature, relative humidity, and pH were highly correlated with concentrate oxidation.

Panskyite, Pd9Ag2Pb2S4, is a new mineral (IMA2020–039) discovered in the platinum-group element mineralisation of the Southern Kievey ore occurrence of the Fedorova–Pana layered intrusion, Kola Peninsula, Russia. It forms tiny anhedral grains (of 0.5 to 10 μm in size) in the interstices of rock-forming silicates, often forming tiny inclusions in base-metal sulfides (millerite, chalcopyrite, bornite and chalcocite) and complex intergrowths with other platinum group minerals (zvyagintsevite, laflammeite, vysotskite, thalhammerite, unnamed phase Pd9Ag2(Tl,Pb)2S4and others). In plane-polarised light, panskyite is creamy white with weak bireflectance, weak pleochroism and distinct anisotropy with brown to grey rotation tints; it exhibits no internal reflections. Reflectance values for panskyite in air (R1,R2in %) are: 43.8, 44.1 at 470 nm; 44.4, 44.7 at 546 nm; 45.6, 45.8 at 589 nm; and 47.2, 47.2 at 650 nm. Twelve electron-microprobe analyses of panskyite gave an average composition: Pd 55.61, Ag 12.36, Pb 23.50, Fe 0.21, Ni 0.24 and S 7.17 total 99.09 wt.%, corresponding to the formula (Pd9.05Fe0.07Ni0.07)Σ9.19Ag1.98Pb1.96S3.87based on 17 atoms; the average of nine analyses on the synthetic analogue is: Pd 57.02, Ag 14.17, Pb 21.81 and S 7.44, total 100.44 wt.%, corresponding to Pd9.07Ag2.22Pb1.78S3.93. The density, calculated on the basis of the empirical formula, is 9.81 g/cm3. The mineral is tetragonal, space groupI4/mmm, witha= 7.973(3),c= 9.139(3) Å,V= 581.0(4) Å3andZ= 2. The crystal structure was solved from the single-crystal and powder X-ray diffraction data of synthetic Pd9Ag2Pb2S4. Panskyite is isostructural with thalhammerite (Pd9Ag2Bi2S4). The mineral name is for the locality, the Pansky massif of the Fedorova–Pana layered intrusion in the Kola Peninsula, Russia.