Sulfide Minerals Research Articles

Advances in Copper Extraction: Sustainable Approaches and Bioleaching Techniques

The environmental impacts of mining and mineral processing, particularly in developing countries, have been increasingly significant. Mining activities, especially in open-pit mines and the extraction of copper from sulfide ores, generate pollution and acid leakage that harm ecosystems. Given the abundant presence of copper in nature, particularly in sulfide minerals, developing environmentally friendly extraction methods is paramount. This study evaluates modern and sustainable methods for copper extraction from the Aynak copper mine, one of the largest copper mines in Afghanistan. Specifically, it compares and assesses bioleaching and hydrometallurgical methods as environmentally friendly alternatives to traditional pyrometallurgical (smelting) processes in copper extraction. Compared to pyrometallurgical methods, the study investigates the environmental impacts and economic efficiency of bioleaching and hydrometallurgical methods. The results indicate that biotechnological methods, such as bioleaching, significantly reduce environmental impacts, improve production efficiency, and lower operational costs. In contrast, pyrometallurgical methods are associated with higher environmental and economic costs. Given the advantages of biotechnological methods, it is recommended that these methods be adopted as sustainable alternatives for copper extraction from low-grade ores at the Aynak copper mine, especially from sulfide ores, to promote environmentally and economically sustainable development in the sector.

Using δ65Cu and δ34S to determine the fate of copper in stream waters draining porphyry mineralization: Implications for exploration targeting

The fate of metals, such as Cu, in stream waters draining porphyry mineralization is commonly controlled by several natural processes such as sorption, microbial processes, and ligand availability. Isotopes of Cu offer a novel approach to understanding these processes and determining metal sources within complicated mineralogical systems. Drainages at the Casino Cu-Au-Mo porphyry deposit, Yukon, Canada exhibit circumneutral (pH > 5) in Casino Creek and natural acid rock drainage (pH < 3.5) in Proctor Gulch with the precipitation of schwertmannite (Fe3+). Isotopic systems δ65Cu and δ34Ssulfate indicate different metal sources, with signatures of both hypogene and supergene mineralization. Waters from Proctor Gulch contain δ65Cu values (< −0.5 ‰) consistent with supergene Cu sources from the leached or oxide portion of the mineralization. Comparatively, drainage in the upper part of Casino Creek contains a δ65Cu composition (> 0.5 ‰) characteristic of Cu sourced from hypogene sulfide mineral oxidation. Variation in metal sources is similarly supported by aqueous δ34Ssulfate values in the stream waters, which suggest mixing of S derived from a sulfide mineral phase and a much heavier sulfate mineral (e.g., gypsum or anhydrite). Isotopic fractionation of Cu in the dissolved (<0.45 μm) phase presents two predominant controls on Cu dispersion. The natural acid conditions in Proctor Gulch favor the preferential co-precipitation of 63Cu with schwertmannite but could be influenced by intracellular assimilation or adsorption by microbes, which also has been shown to preferentially favor 63Cu. Copper isotopic fractionation results in a gradient of increasing δ65Cu values in waters downstream. In Casino Creek, higher pH conditions favor the precipitation of Fe(OH)3 and the preferential adsorption of 65Cu, resulting in decreasing δ65Cu values downstream. Copper concentrations in stream waters remain elevated (up to 4.1 μg/L) above ambient background (1.9 μg/L) levels up to 11 km downstream of the deposit. Given the abundance of surface water in many parts of northern Canada, hydrogeochemical prospecting using broad scale stream water catchment analysis is clearly a viable greenfield exploration methodology.

Role of impurities in the semiconducting properties of natural pyrite: Implications for the electrochemical accumulation of visible gold and formation of hydrothermal gold deposits

Abstract Pyrite (FeS2), the most abundant sulfide mineral on Earth, typically contains a host of minor and trace elements, including As, Co, Ni, and Au. It is an important semiconductor with unique structural properties markedly influenced by elemental impurities. However, whether the change in semiconducting properties of natural pyrite is caused by the type and concentration of trace elements or by a non-stoichiometry-related doping mechanism remains uncertain. Moreover, the effect of semiconducting properties on the enrichment mechanism of Au has not been well addressed. Here, we investigate microscopic pyrite crystals from the Heilangou gold field (HGF) in the eastern Jiaodong Peninsula using field emission scanning electron microscopy (SEM), electron probe microanalysis (EPMA), in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), potential-Seebeck microprobe (PSM), and thermoelectric measurements. The results demonstrate that pyrite grains show either p- or n-type conductivity depending on chemical compositions. Pyrite enriched in As, which typically substitutes for S in the crystal structure, tends to be p-type with a positive Seebeck coefficient, whereas pyrite crystals enriched in Co, Ni, Cu, and Zn, as well as those depleted in As, are typically n-type. Moreover, As shows the strongest influence on the semiconducting properties of natural pyrite crystals and a strong positive correlation with Au. We observed that visible Au grains are preferentially accumulated on individual domains of sulfides (e.g., As-rich pyrite) that act as cathodes, suggesting that electrical p-n junctions in sulfides drive electrochemical reactions with ore-forming fluids, resulting in the deposition of visible Au. The electrochemical precipitation mechanism of Au may account for the formation of other types of hydrothermal Au deposits.

Selective and enhanced recovery of Pb and Zn from mixed polymetallic sulfide minerals: Synergism of oxidative-acid leaching

Selective and enhanced recovery of Pb and Zn from mixed polymetallic sulfide minerals: Synergism of oxidative-acid leaching

Berndlehmannite: A new V-bearing sulfide mineral from the black shale-hosted Zhongcun vanadium deposit, South China

Abstract Berndlehmannite, Cu(CrV)S4, is a newly identified V-bearing sulfide mineral discovered in the black shale-hosted Zhongcun vanadium deposit, South China. It is abundant in a phosphatic nodule-rich layer and is commonly mineralogically associated with roscoelite, quartz, and framboidal pyrite. Berndlehmannite exhibits black color in hand specimens with a black streak and it comprises subhedral grains that vary in size from 20 to 120 μm. The mineral is opaque with a cream-colored polished surface under reflected light. It has a Mohs hardness of 3½ with a {111} perfect cleavage, and its calculated density is 4.17 g·cm−3. Berndlehmannite is cubic, with space group Fd-3m; the unit-cell parameters determined from powder data are a = 9.8585(22) Å, V = 958.1(6) Å3, and Z = 8. The unit-cell parameters by single-crystal X-ray diffraction are a = 9.8374(2) Å, V = 952.01(6) Å3, Z = 8, and the final value of R is 0.015. The mineral is a member of the carrollite subgroup within the thiospinel group, featuring (Cr,V)S6 in octahedral coordination and CuS4 in tetrahedral coordination. The calculated empirical formula from electron-probe microanalysis is (Cu+0.99Zn0.02)Σ1.01(Cr3+0.87V4+1.00Sb0.07As0.04)Σ1.98S4.01 with an average V content of 17.0 wt%. It has the highest V component compared to other V-bearing minerals in black shales and may provide new insight into the vanadium enrichment mechanism in black shales. Berndlehmannite is named to honor Bernd Lehmann (1950- ), Professor emeritus of Economic Geology at Technische Universität Clausthal, Germany.

Interpreting the Complexity of Sulfur, Carbon, and Oxygen Isotopes From Sulfides and Carbonates in a Precious Metal Epithermal Field: Insights From the Permian Drake Epithermal Au-Ag Field of Northern New South Wales, Australia

The Drake Goldfield, also known as Mount Carrington, is located in north-eastern New South Wales, Australia. It contains a number of low–intermediate-sulfidation epithermal precious metal deposits with a current total resource of 724.51 metric tons of Ag and 10.95 metric tons of Au. These deposits occur exclusively within the Drake Volcanics, a 60 × 20 km NW-SE trending sequence of Late Permian volcanics and related epiclastics. Drilling of the Copper Deeps geochemical anomaly suggests that the volcanics are over 600 m thick. The Drake Volcanics are centered upon a geophysical anomaly called “the Drake Quiet Zone” (DQZ), interpreted to be a collapsed volcanic caldera structure. A total of 105 fresh carbonate samples were micro-drilled from diamond drillcores from across the field and at various depths. A pXRD analysis of these carbonates identified five types as follows: ankerite, calcite, dolomite, magnesite, and siderite. Except for three outlier values (i.e., −21.32, −19.48, and 1.42 ‰), the δ13CVPDB generally ranges from−15.06 to −5.00 ‰, which is less variable compared to the δ18OVSMOW, which varies from −0.92 to 17.94 ‰. μ-XRF was used to analyze the elemental distribution, which indicated both syngenetic/epigenetic relationships between calcite and magnesite. In addition, a total of 53 sulfide samples (primarily sphalerite and pyrite) from diamond drillcores from across the Drake Goldfield were micro-drilled for S isotope analysis. Overall, these have a wide range in δ34SCDT values from −16.54 to 2.10 ‰. The carbon and oxygen isotope results indicate that the fluids responsible for the precipitation of carbonates from across the Drake Goldfield had complex origins, involving extensive mixing of hydrothermal fluids from several sources including those of magmatic origin, meteoric fluids and fluids associated with low-temperature alteration processes. Sulfur isotope ratios of sulfide minerals indicate that although the sulfur was most likely derived from at least two different sources; magmatic sulfur was the dominant source while sedimentary-derived sulfur was more significant for the deposits distal from the DQZ, with the relative importance of each varying from one deposit to another. Our findings contribute to a greater understanding of Au-Ag formation in epithermal environments, particularly in collapsed calderas, enhancing exploration strategies and models for ore deposition.

Why gold deposits are not caused by fluids from the mantle

Any model invoking gold fluids coming through crustal rocks at granulite facies grade or coming from the mantle is built on a misunderstanding of the way aqueous fluids interact with rocks at high temperature, above their solidus. It is not currently explained in such models how aqueous fluids pass through rocks at granulite facies grade without being involved in melting. At temperatures above 650–750 °C, crustal rocks melt in the presence of an aqueous fluid with the latter being consumed, the amount of melt generally being proportional to the amount of fluid involved. This means auriferous hydrothermal fluids are unable to infiltrate hot lower crust from the mantle. An alternative model exists that avoids this problem, at least for typical gold-only deposits, for example Kalgoorlie. It involves fluid generation by metamorphic devolatilisation in the mid-crust at the greenschist–amphibolite facies transition, at around 450 °C. This process generates significant volumes of aqueous fluid during prograde metamorphism. In the presence of carbonate and sulfide minerals, the resulting fluid is H2O–CO2–H2S dominated by low salinity, a composition conducive to gold dissolution. A strength of this model is that the fluid will become gold-bearing as it is generated. As more or less all mineral grains in the rock are involved in the devolatilisation, gold present at parts-per-billion level in grains as well as on grain boundaries is accessible to the fluid.

The Evolution of Permian Mafic–Ultramafic Magma of the Yunhai Intrusion in the Northern Tianshan, Northwest China, and Its Implications for Cu-Ni Mineralization

The early Permian mafic–ultramafic intrusion-related Cu-Ni mineralization in Northern Tianshan offers valuable insights into the nature of the mantle beneath the Central Asian Orogenic Belt (CAOB) and enhances the understanding of magmatic sulfide mineralization processes in orogenic environments. The Yunhai intrusion, rich in Cu-Ni sulfides, marks a significant advancement for Cu-Ni exploration in the covered regions of the western Jueluotag orogenic belt in Northern Tianshan. This intrusion is well-differentiated, featuring a lithological assemblage of olivine pyroxenite, hornblende pyroxenite, gabbro, and diorite, and contains about 50 kilotons of sulfides with average grades of 0.44 wt% Ni and 0.62 wt% Cu. Sulfide mineralization occurs predominantly as concordant layers or lenses of sparsely and densely disseminated sulfides within the olivine pyroxenite and hornblende pyroxenite. In situ zircon U-Pb dating for the Yunhai intrusion indicates crystallization ages between 288 ± 1 and 284 ± 1 Ma, aligning with several Cu-Ni mineralization-associated mafic–ultramafic intrusions in Northern Tianshan. Samples from the Yunhai intrusion exhibit enrichment in light rare earth elements (LREE), distinct negative Nb and Ta anomalies, positive εNd(t) values ranging from 2.75 to 6.56, low initial (87Sr/86Sr)i ratios between 0.7034 and 0.7053, and positive εHf(t) values from 9.27 to 15.9. These characteristics, coupled with low Ce/Pb (0.77–6.55) and Nb/U (5.47–12.0) ratios and high Ti/Zr values (38.7–102), suggest very restricted amounts (ca. 5%) of crustal assimilation. The high Rb/Y (0.35–4.27) and Th/Zr (0.01–0.03) ratios and low Sm/Yb (1.47–2.32) and La/Yb (3.10–7.52) ratios imply that the primary magma of the Yunhai intrusion likely originated from 2%–10% partial melting of weak slab fluids–metasomatized subcontinental lithospheric mantle (peridotite with 2% spinel and/or 1% garnet) in a post-collisional environment. The ΣPGE levels in the Yunhai rocks and sulfide-bearing ores range from 0.50 to 54.4 ppb, which are lower compared to PGE-undepleted Ni-Cu sulfide deposits. This PGE depletion in the Yunhai intrusion’s parental magma may have been caused by early sulfide segregation from the primary magma at depth due to the high Cu/Pd ratios (43.5 × 103 to 2353 × 103) of all samples. The fractional crystallization of minerals such as olivine and pyroxene might be a critical factor in provoking significant sulfide segregation at shallower levels, leading to the extensive disseminated Cu-Ni mineralization at Yunhai. These characteristics are similar to those of typical deposits in the eastern section of the Jueluotage orogenic belt (JLOB), which may indicate that the western and eastern sections of the belt have the same ore-forming potential.

A Genetic Model for the Biggenden Gold-Bearing Fe Skarn Deposit, Queensland, Australia: Geology, Mineralogy, Isotope Geochemistry, and Fluid Inclusion Studies

The Biggenden gold-bearing Fe skarn deposit in southeast Queensland, Australia, is a calcic magnetite skarn that has been mined for Fe and gold (from the upper portion of the deposit). Skarn has replaced volcanic and sedimentary rocks of the Early Permian Gympie Group, which formed in different tectonic settings, including island arc, back arc, and mid-ocean ridge. This group has experienced a hornblende-hornfels grade of contact metamorphism due to the intrusion of the Late Triassic Degilbo Granite. The intrusion is a mildly oxidized I-type monzogranite that has geochemical characteristics intermediate between those of granitoids typically associated with Fe-Cu-Au and Sn-W-Mo skarn deposits. The skarn mineralogy indicates that there was an evolution from prograde to various retrograde assemblages. Prograde garnet (Adr11-99Grs1-78Alm0-8Sps0-11), clinopyroxene (Di30-92Hd7-65Jo0-9), magnetite, and scapolite formed initially. Epidote and Cl-bearing amphibole (mainly ferropargasite) were the early retrograde minerals, followed by chlorite, calcite, actinolite, quartz, and sulfides. Late-stage retrograde reactions are indicated by the development of nontronite, calcite, and quartz. Gold is mainly associated with sulfide minerals in the retrograde sulfide stage. The fluids in equilibrium with the ore-stage calcites had δ13C and δ18O values that indicate deposition from magmatically derived fluids. The calculated δ18O values of the fluids in equilibrium with the skarn magnetite also suggest a magmatic origin. However, the fluids in equilibrium with epidote were a mixture of magmatic and meteoric water, and the fluids that deposited chlorite were at least partly meteoric. δD values for the retrograde amphibole and epidote fall within the common range for magmatic water. Late-stage chlorite was deposited from metasomatic fluids depleted in deuterium (D), implying a meteoric water origin. Sulfur isotopic compositions of the Biggenden sulfides are similar to other skarn deposits worldwide and indicate that sulfur was most probably derived from a magmatic source. Based on the strontium (87Sr/86Sr) and lead (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb) isotope ratios, the volcanic and sedimentary rocks of the Gympie Group may have contributed part of the metals to the hydrothermal fluids. Lead isotope data are also consistent with a close age relationship between the mineralization at Biggenden and the crystallization of the Degilbo Granite. Microthermometric analysis indicates that there is an overall decrease in fluid temperature and salinity from the prograde skarn to retrograde alterations. Fluid inclusions in prograde skarn calcite and garnet yield homogenization temperatures of 500 to 600 °C and have salinities up to 45 equivalent wt % NaCl. Fluid inclusions in quartz and calcite from the retrograde sulfide-stage homogenized between 280 and 360 °C and have lower salinities (5–15 equivalent wt % NaCl). In a favored genetic model, hydrothermal fluids originated from the Degilbo Granite at depth and migrated through the shear zone, intrusive contact, and permeable Gympie Group rocks and leached extra Fe and Ca and deposited magnetite upon reaction with the adjacent marble and basalt.

Evolution of the Hydrothermal Fluids Inferred from the Occurrence and Isotope Characteristics of the Carbonate Minerals at the Pogo Gold Deposit, Alaska, USA

Pogo is identified as a deep-seated, intrusion-related gold deposit. Carbonate minerals have a close spatial relationship to hydrothermal gold mineralization in all of its principal ore zones. The carbon and oxygen isotopic ratios of carbonate minerals (siderite, ankerite, and calcite) present within the deposit illustrate the isotopic evolution of the ore-forming fluid. The initial hydrothermal fluid phase is interpreted to be magmatic in origin. The fluid evolution was characterized by a gradual decrease in δ18O and a slight increase in δ13C with decreasing temperature. The dominant carbon-bearing species was CO2, with methane introduced sporadically. Siderite is associated with early-stage mineralization and occurs with ankerite in main-stage ore assemblages. Calcite is recognized in the later stages of mineralization. Gold in the Pogo deposit occurs as native gold, Au-Bi-Te minerals, inclusions in sulfide minerals, or as “invisible gold”. The latter is found in pyrite, chalcopyrite, arsenopyrite, and quartz, based on ion microprobe analysis. The presence of invisible gold in these minerals has significant metallurgical implications for gold processing at the Pogo mine.

An Experimental and Quantum Chemical Calculation Study on the Performance of Different Types of Ester Collectors.

Ester collectors have rapidly developed into the main flotation collectors for copper sulfide minerals since they were developed. In this study, the collecting performance of four collectors, O-isopropyl-N-ethyl thionocarbamate ester (IPETC), 3-pentyl xanthate acrylate ester (PXA), O-isobutyl-N-allyl-thionocarbamate (IBALTC), and O-isobutyl-N-isobutoxycarbonyl-thionocarbamate (IBIBCTC), was investigated through microflotation tests, microcalorimetric measurements, and quantum chemical calculations. The results of the microflotation tests show that IBALTC and IPETC have stronger collecting abilities than IBIBCTC and PXA; the order of collecting ability is IBALTC > IPETC > IBIBCTC > PXA. The microcalorimetry test also shows that the adsorption heat of the former two is higher. Quantum chemical calculations show the energy difference between the HOMOs of the collector and the LUMOs of minerals. The electrostatic potential extremum around S atom and the first ionization potential of IPETC and IBALTC are similar and were smaller than IBIBCTC and PXA, which shows that the collecting ability of the former two is similar and stronger than the latter two. Among the collectors, the S atom polarizability, electrophilic, and nucleophilic attack index of IBALTC are the largest, indicating that its electronic deformation capability and nucleophilic properties are the strongest, which results in the strongest coordination interaction with the copper ions in copper sulfide minerals and thus the highest collecting ability. The S atom polarizability, electrophilic, and nucleophilic attack index of PXA are the smallest, indicating that its electronic deformation capability and nucleophilicity are the weakest, and its collecting ability is the weakest. The coordination between collector and mineral surface was analyzed theoretically. The research results are of great help to the design and development of ester collectors.

Controls of Neoproterozoic magmatism on Ni Cu sulfide mineralization in the Jiangnan Orogenic Belt, South China: An example from the newly discovered Sibao Ni Cu sulfide deposit

Controls of Neoproterozoic magmatism on Ni Cu sulfide mineralization in the Jiangnan Orogenic Belt, South China: An example from the newly discovered Sibao Ni Cu sulfide deposit

Microscopic evidence for nanoparticle-mediated growth of native gold in sulfide deposits at the Higashi-Aogashima Knoll Caldera hydrothermal field.

Gold (or electrum) in hydrothermal fluid precipitates directly from gold sulfide complex and/or partly via suspended nanoparticles. The hydrothermal fluid contains "invisible gold" that is atomically dispersed in sulfide minerals or as nanoparticles with a size of less than 10 nm. However, the contribution of these gold nanoparticles to the formation of native gold and its alloy with silver (electrum) remains unclear. The Higashi-Aogashima Knoll Caldera hydrothermal field, south of Tokyo, Japan, is an area of significant seafloor hydrothermal activity that is known for high-grade gold-containing minerals in sulfide-rich rocks. In this study, dry-polished thin sections were created to minimize sample damage and scanning and transmission electron microscopy were used to investigated the cross-sectional and three-dimensional morphologies of native gold grains in a sulfide-rich mound rock from the Central Cone site of the caldera. The surfaces of the gold grains comprised nanoparticles with sizes of 5-50 nm that were also attached to their periphery, which suggests that gold nanoparticles in deep-sea hydrothermal fluid were involved in the mineralization of the gold. In addition, the distribution of silver was uneven within the gold grains, which suggests that the gold precipitation comprised multiple stages at different temperatures that resulted in the post-deposition or secondary remobilization of silver.

Discovery of Trogtalite (CoSe2) in the Qianjiadian Sandstone‐Type Uranium Deposit in China

ABSTRACTCobalt (Co), selenium (Se) and uranium (U) are strategic and critical elements with significant global demand. Typically, cobalt is mainly recovered as a by‐product from sulfide and sulfoarsenide minerals associated with copper, nickel, and iron, while its occurrence as independent minerals, particularly trogtalite (cubic CoSe2), is rare. This study reports the presence of trogtalite in a sandstone‐type uranium deposit in China. It was identified in the Qianjiadian deposit in the southwestern Songliao Basin, through electron probe microanalysis (EPMA) and Raman spectroscopy analysis (wavenumber 188 cm−1). The trogtalite occurs as cubic or polyhedral microcrystals, distributing as detrital mineral dispersed in the clay matrix or enclosed in detrital quartz or feldspar in uranium‐mineralized sandstones from Upper Cretaceous Yaojia Formation. The sandstone also contains selenides, including clausthalite, ferroselite, and krut'aite, which are typical cobalt mineralization associations found in the deposits in Argentina and Congo. The uranium‐mineralized rocks in the Qianjiadian deposit are enriched in Se, suggesting the co‐enrichment of Se and U during the mineralization. Thus, Se serves as an indicator of uranium mineralization in this deposit.

Metal mobilisation and fines migration in pure CO2 and impure CO2-SO2-NO reactions of carbon storage site core.

Carbon dioxide geological storage is proposed as part of the solution to reach net zero emissions. The potential to mobilise heavy metals to low salinity groundwater through CO2 water rock geochemical reactions is a potential environmental risk factor, if CO2 migrates. Previous studies have focused on pure CO2 reactivity, however CO2 streams from hard to abate industries can contain gas impurities. Reservoir sandstone and mudstone drill cores from a proposed low salinity CO2 storage demonstration site were reacted at in situ conditions with pure CO2 or an impure NO-SO2-CO2 stream. Sandstones hosted Rb in illite analysed via synchrotron XFM. Arsenic (As) was hosted in pyrite; and Pb, Cr, Mn in siderite rimming intergranular pores. Mudstone contained Zn, Co, Ni, Cu, As, Pb in sphalerite, and Rb in illite and K-feldspar. In impure NO-SO2-CO2 experiments the lowered pH and oxidising conditions initially released higher concentrations of metals including Pb, Zn, Co into solution compared to pure CO2 reactions. Higher concentrations of Zn (Mn and Co) were released from sphalerite in the mudstone. Fe-chlorite, K-feldspar, and carbonate dissolution released Rb, Si, Fe, Ca, and Mg. Elevated dissolved Pb was mainly from siderite and sulphide mineral reaction in sandstones. Mobilised As was released prior to CO2 addition from desorption and ion exchange. Clay and fines migration into pores occurred in both pure and impure CO2 reactions that has the potential to impact fluid migration. A portion of metals including Fe, Ni, Cr were subsequently incorporated in precipitated Fe hydr(oxy)oxides where the co-injected NO induced oxidising conditions. Rock mineral content and the injected gas mix were the main controls on metal mobilisation to formation water. Further work should investigate new gas mixtures that may be expected in storage hubs, from blue hydrogen or from direct air capture.

Protonation behavior study of the active sites on typical sulfide minerals surface using surface complexation model

Protonation behavior study of the active sites on typical sulfide minerals surface using surface complexation model

Variscan Gornjane granitoid as an alternative cold-water reservoir in the ore-baring and mining area of eastern Serbia: Quantitative-qualitative characterization (Carpathian-Balkan belt, Getic unit)

The diminishing high-quality groundwater reservoirs have sparked significant interest in hard-rock aquifers, especially in active mining and raw material exploration areas. This paper aims to forecast the quantity and quality of alternative water resources in the area, thus facilitating the planning and design of the existing water resource systems. The focal point is the groundwater accommodated within basement-type alternative igneous aquifers nestled within an active mining and exploration province belonging to the Carpathian-Balkan fold-and-thrust belt (Banat-Timok Province/Banatitic Belt, sector in eastern Serbia). Despite their lower water-bearing capacity, we underscore the significant hydrogeological potential of natural water igneous-type aquifers, such as the Variscan Gornjane massif.For the first time, this research identifies different reservoirs across the granite massif, providing a fresh perspective on the regional water resource systems. By categorizing reservoirs based on porosity type, flow rates, depth of reservoir rocks (in the depth range of 50 m), and distribution, this study significantly enhances the forecasting of the new water resource system, underlining the importance of this research in the field of water resources and mining. In addition to faulted sections of granite, aquifers are formed in the area characterized by weathered and decomposed granite fragments, often referred to as gruss deposits. The gruss layer has a flow rate reaching up to 0.01 l/s. In terms of the water quality, the groundwaters of the Gornjane granite massif mostly do not contain elements that are above the maximum permitted concentrations for drinking water. However, the occurrence of the elements Fe Mn in some water samples and the presence of Al Pb in one sample, as well as Se, As, Cu, Zn, Ag, Cd, Ga, and Bi, suggest the contact of water with sulfide mineralization detected in granite rocks of Rudna Glava-Tanda-Luka area, raising concerns about potential water quality issues.

Enhanced Mo-Cu sulfide minerals flotation separation via depressing molybdenite with a novel eco-friendly polysaccharide

Enhanced Mo-Cu sulfide minerals flotation separation via depressing molybdenite with a novel eco-friendly polysaccharide

ОСОБЕННОСТИ ФОРМИРОВАНИЯ ЭЛЕМЕНТНОГО СОСТАВА ПОЧВ В КОНТРАСТНЫХ ГЕОЛОГИЧЕСКИХ УСЛОВИЯХ (р. МЗЫМТА, ЧЕРНОМОРСКОЕ ПОБЕРЕЖЬЕ РОССИИ)

The Mzymta River (Black Sea coast, Russia) erodes different types of rocks. Among them, mudstones, siltstones and shales are predominating, and carbonate and clay-carbonate rocks are present in smaller quantities, and occasionally eruptive rocks are encountered. The area is characterized by the occurrence of polymetallic, gold, sulphide, rare-metal and rare-earth mineralization. The studies have shown that the differences in the quantitative and qualitative elemental composition of soils in the Mzymta River valley (determined by mass-spectrometric method for 61 elements) correlate with underlying rocks. The amount of rare-earth elements and their fractionation distinguishes soils formed on igneous or sedimentary soil-forming rocks. Ca/Mg ratio can be considered as a diagnostic sign of soils formed on clayey or carbonate rocks. The influence of ore mineralisation zones on soils is manifested in the close correlation of the main ore and associated elements (As, Co, Pb, Cu, Ni, Bi, Sb and Zn) with Fe and Al.

Comprehensive Assessment of Environmental Behavior of Mine Tailings for Sustainable Waste Management and Mitigation of Pollution Risks

The substantial volumes of tailings produced during ore beneficiation present significant challenges for sustainable management due to potential public health hazards, particularly from metal leaching. The risk associated with tailings varies greatly depending on their mineralogical composition and climatic conditions. If tailings are classified as a non-hazardous by-product, they may serve as secondary raw materials, offering a sustainable alternative to the reliance on non-renewable primary resources. In this study, the recycling feasibility of tailings from an active copper mine was assessed through mineralogical characterization, environmental tests (e.g., static, kinetic, and leaching tests), and geochemical modeling. This multi-faceted approach aimed to predict the geochemical behavior and reactivity of tailings under varying conditions. Results from the static tests indicated that the tailings were non-acid generating. Weathering cell tests revealed circumneutral pH conditions (6.5–7.8), low sulfide oxidation rates, and low instantaneous metal concentrations (&lt;1 mg/L), except for copper (0.6–3.5 mg/L) and iron (0.4–1.4 mg/L). These conditions are attributed to the low abundance of sulfide minerals, such as pyrite, chalcopyrite, bornite, covellite (&lt;0.1 wt.%), and chalcocite (0.2 wt.%), which are effectively encapsulated within gangue minerals. Additionally, the presence of neutralizing minerals, specifically dolomite (27.4 wt.%) and calcite (2.4 wt.%), further stabilizes pH and promotes metal sequestration in secondary mineral forms. The Toxicity Characteristic Leaching Procedure (TCLP) test confirmed low leachability, classifying the tailings as non-hazardous.