Minerals

30 pages, 4224 KB

Open AccessReview

Endogenic Gold Metallogeny in Heilongjiang Province, NE China: Implications for Tectonic Transition and Composite Metallogenic Systems

by Tiesheng Li, Sheng Lu, Mingxin Duan, Hui Gong, Zhichao Song and Lingyun Hu

Minerals 2026, 16(8), 859; https://doi.org/10.3390/min16080859 - 21 Aug 2026

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Abstract

Heilongjiang Province, northeastern China, occupies a key metallogenic position between the eastern Central Asian Orogenic Belt and the western Pacific continental margin. This review integrates published geological, geochronological, fluid–inclusion, and H–O–S–Pb isotope data to evaluate tectonic controls on endogenic gold mineralization. Four principal [...] Read more.

Heilongjiang Province, northeastern China, occupies a key metallogenic position between the eastern Central Asian Orogenic Belt and the western Pacific continental margin. This review integrates published geological, geochronological, fluid–inclusion, and H–O–S–Pb isotope data to evaluate tectonic controls on endogenic gold mineralization. Four principal metallogenic episodes are recognized: Caledonian porphyry-related mineralization associated with Paleo–Asian Ocean subduction–accretion; Variscan skarn-forming magmatic–hydrothermal activity; Indosinian post-collisional structurally focused and epithermal hydrothermal activity; and Yanshanian mineralization characterized by Late Jurassic compressional reworking followed by a dominant Cretaceous Paleo–Pacific-related magmatic–hydrothermal pulse. Ore-forming fluids evolved non-monotonically from Paleozoic high-temperature magmatic fluids to more heterogeneous crustal, metamorphic, and meteoric–water–influenced systems. Zhengguang and Laozuoshan provide clear evidence for temporally distinct superimposed mineralization. Later hydrothermal reactivation could either remobilize and reconcentrate Au or leach, disperse, and obscure earlier mineralization. Exploration should therefore prioritize reactivated structural corridors where intrusive centers, reactive wall rocks, volcanic basins, and multi-stage alteration overlap. Full article

(This article belongs to the Special Issue Metallogenic Enrichment in Orogenic Systems: Processes Linking Crustal Evolution to Ore Genesis)

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24 pages, 88704 KB

Open AccessArticle

Geochemical Characteristics of the Shuibutou Sedimentary Manganese Deposit in Southern Hunan Province, South China

by Ximing Wu, Chen Yu, Zimeng Zhao, Jinmei Xu, Xiao Ma, Yinghong Qin, Dapeng Chen, Han Tang, Junwei Xu, Bin Li, Zhi Liu, Xianghua Liu and Yong Wang

Minerals 2026, 16(8), 858; https://doi.org/10.3390/min16080858 - 21 Aug 2026

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Abstract

Permian sedimentary manganese carbonate deposits in the Qiling Basin exhibit substantial resource potential, yet their depositional environments and precipitation pathways remain insufficiently constrained. This study integrates petrographic, mineralogical, whole-rock geochemical, and carbonate C–O isotope data from the Shuibutou Mn deposit in southern Hunan. [...] Read more.

Permian sedimentary manganese carbonate deposits in the Qiling Basin exhibit substantial resource potential, yet their depositional environments and precipitation pathways remain insufficiently constrained. This study integrates petrographic, mineralogical, whole-rock geochemical, and carbonate C–O isotope data from the Shuibutou Mn deposit in southern Hunan. We compare this deposit with the coeval Dongxiangqiao deposit and other Permian marine sedimentary Mn deposits to constrain its depositional setting, Mn-carbonate precipitation mechanisms, and potential Mn sources. The Shuibutou ores contain 10.88–17.18 wt.% MnO and are characterized by spherulitic–oolitic textures, abundant bioclasts, and framboidal pyrite. Mo–U enrichment indicates anoxic bottom waters, whereas the near-marine δ¹³C_carb values of ore carbonates (−0.24‰ to 1.28‰) are consistent with precipitation within a marine carbonate system and suggest direct precipitation of Mn(II) carbonates from dissolved Mn²⁺ under anoxic conditions. In this setting, dissolved Mn²⁺ accumulated below the chemocline. Partial dissolution of platform-derived calcite grains near the chemocline increased local dissolved inorganic carbon and alkalinity, driving Mn-carbonate supersaturation and the authigenic precipitation of manganoan calcite, ultimately forming manganese carbonate ores. The low Al/(Al + Fe + Mn) ratios, high Fe/Ti ratios, and Co–Ni–Zn and REY geochemical characteristics are consistent with a possible contribution from Mn-rich deep fluids to the dissolved Mn²⁺ inventory of the basin waters. Similarities in mineralogy, geochemistry, and depositional setting between Shuibutou and Dongxiangqiao point to a possible regional role for the direct precipitation of Mn(II) carbonates under anoxic conditions in the Middle Permian Qiling Basin. Relatively deep intraplatform basins may therefore represent favorable targets for manganese carbonate exploration and provide a reference for exploration targeting of Permian sedimentary Mn deposits within the Qiling Basin. Full article

(This article belongs to the Special Issue Metallogenic Enrichment in Orogenic Systems: Processes Linking Crustal Evolution to Ore Genesis)

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19 pages, 6614 KB

Open AccessArticle

Mineral Chemistry and Genetic Constraints on Yiyuan Jade, Eastern Qinling Orogen, China

by Xu Cheng, Hongshun Yang, Jianhan Huang, Yazhou Fan and Danli Chen

Minerals 2026, 16(8), 857; https://doi.org/10.3390/min16080857 - 21 Aug 2026

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Abstract

Yiyuan jade, a specific gem-quality jade variety in the East Qinling Orogen, occurs as lenticular and vein-shaped bodies hosted within the dolomite and biotite-quartz marble of the Neoproterozoic Meiyaogou Formation. Based on detailed petrological and mineralogical characterization, three subtypes are defined: tremolite jade [...] Read more.

Yiyuan jade, a specific gem-quality jade variety in the East Qinling Orogen, occurs as lenticular and vein-shaped bodies hosted within the dolomite and biotite-quartz marble of the Neoproterozoic Meiyaogou Formation. Based on detailed petrological and mineralogical characterization, three subtypes are defined: tremolite jade (nephrite), serpentine jade (a green variety of serpentine group minerals that resembles true jade), and their transitional varieties. Among these, tremolite jade is predominantly white, moon-white, and light green, whereas serpentine jade (gem-quality serpentine) exhibits dark green, yellow-green, and yellow coloration. Comprehensive mineral composition analyses are presented, encompassing amphibole, serpentine, carbonate minerals, and titanite in metagabbro, aiming to constrain the physicochemical conditions and genetic model of these jades. We propose that tremolite jade and serpentine jade are probably formed simultaneously via metasomatic processes, primarily governed by variations in fluid volume and the activities of SiO₂ and CO₂. The serpentine jade is interpreted as serpentinized marble, within which local serpentine aggregation forms serpentine jade akin to Lantian jade in the western East Qinling region. The tremolite jade closely resembles Hetian tremolite jade within geochemical and mineralogical characteristics but differs significantly from serpentine-type tremolite jade associated with ultramafic rocks, thereby confirming its classification as dolomite-type jade. Application of the Ti-in-tremolite geothermometer yields a formation temperature exceeding 400 °C. Integrated with regional geochronological constraints, our findings link the formation of Yiyuan tremolite jade and serpentine jade to tectonic activity driven by the Late Devonian subduction of the Erlangping back-arc basin. This study not only enhances the current understanding of jade mineralization within collisional orogenic settings but also establishes a robust foundation for future exploration in the East Qinling Orogen. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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28 pages, 19117 KB

Open AccessArticle

Trace Element Content and U-Pb Geochronology of Detrital Rutile in the Cretaceous-to-Eocene Julian and Brkini Flysch Basins (SE Alps and NW Dinarides, Italy and Slovenia)

by Matteo Velicogna, Martina Greco, Lorenzo Tavazzani, Chiara Pisoni, Sergio Andò, Alois Bonifacio, Francesco Princivalle and Davide Lenaz

Minerals 2026, 16(8), 856; https://doi.org/10.3390/min16080856 - 20 Aug 2026

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Abstract

The Cretaceous-to-Eocene Julian (JB) and Brkini (BK) flysch basins have recently been studied for their heavy mineral assemblages; however, the rutile component has so far been neglected. To fill this gap, this study explores their detrital rutile trace element contents and U-Pb ages [...] Read more.

The Cretaceous-to-Eocene Julian (JB) and Brkini (BK) flysch basins have recently been studied for their heavy mineral assemblages; however, the rutile component has so far been neglected. To fill this gap, this study explores their detrital rutile trace element contents and U-Pb ages to define their possible provenance(s). In JB, there are very few rutile grains, mainly related to amphibolite–eclogite facies metamorphic units, with about 80% metapelitic grains. Among the few rutile grains from JB, only eight gave robust U-Pb ages. These ages are all Palaeozoic, resembling those of the closure/opening of the Rheic Ocean and the Variscan orogeny. In BK, the number of rutile grains is much higher than in JB, testifying to differences in the supply areas. The rutile grains are mainly in the amphibolite–eclogite facies, but they decrease, moving upward, accompanied by an increase in UHT. The metapelitic rutile component is higher than 74%. When considering the BK rutile grains, there are no Palaeozoic ages at the bottom of the sequence, while they are newly visible upward. In BK, the most abundant rutile grains show Mesozoic ages that can be considered as representatives of the opening/closure of the Vardar Ocean and the ophiolite emplacement in the Dinarides area. Full article

(This article belongs to the Special Issue Tectonic Setting and Provenance of Sedimentary Rocks)

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29 pages, 59392 KB

Open AccessArticle

Drill-Core SWIR-Based 3D Alteration Modeling and Machine Learning for Gold Prospectivity Prediction at the Tudui–Shawang Gold Deposit, Jiaodong Peninsula

by Guoqing Zhang, Gongwen Wang, Qingming Peng, Kun Liu, Yuchang Chen and Yi Cao

Minerals 2026, 16(8), 855; https://doi.org/10.3390/min16080855 - 20 Aug 2026

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Abstract

Deep exploration in mature gold districts requires subsurface alteration evidence that can be related quantitatively to three-dimensional (3D) geological architecture. This study develops a workflow for the Tudui–Shawang deposit in the Muping–Rushan metallogenic belt that integrates drill-core short-wave infrared (SWIR) spectroscopy, 3D alteration [...] Read more.

Deep exploration in mature gold districts requires subsurface alteration evidence that can be related quantitatively to three-dimensional (3D) geological architecture. This study develops a workflow for the Tudui–Shawang deposit in the Muping–Rushan metallogenic belt that integrates drill-core short-wave infrared (SWIR) spectroscopy, 3D alteration modeling, ore-controlling geological constraints, positive–unlabeled (PU) learning, and ensemble prospectivity prediction. A total of 2140 spectra from 10 drillholes were processed to identify mineral assemblages, extract spectral scalars and feature-shape attributes, classify alteration facies, and construct continuous 3D alteration evidence. Discrete smooth interpolation and indicator kriging were used for continuous and categorical attributes, respectively, and CatBoost, LightGBM, XGBoost, and Random Forest were evaluated within a spatially separated PU-bagging design. Quantitative analyses show that individual SWIR attributes have weak deposit-scale relationships with Au grade. Nevertheless, local IC minima, relatively lower pos2200 values near several mineralized intervals, alteration-facies transitions, and a broader shift toward longer pos2250 wavelengths characterize relevant parts of the mineralized system. FUSE performed best under 1 km × 1 km spatial holdout validation, with an ROC AUC of 0.8900 and a PRAUC of 0.8926. Prediction-area analysis and the 3D probability volume delineated three ranked exploration targets (T1–T3). The results show that drill-core SWIR-derived 3D alteration evidence, when integrated with ore-controlling geology and spatially validated machine learning, provides a practical basis for target prioritization in mature gold districts. Full article

(This article belongs to the Special Issue Application of Machine Learning in Integrated Interpretation of Multi-Scale Geoscience Data)

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44 pages, 18713 KB

Open AccessArticle

Geology and Mineralogical-Geochemical Characteristics of the Volcanic Rocks in the Tunguska Syneclise, Permo-Triassic Siberian Traps Province

by Nadezhda Krivolutskaya, Boris Belyatsky, Svetlana Demidova and Artem Konyshev

Minerals 2026, 16(8), 854; https://doi.org/10.3390/min16080854 - 20 Aug 2026

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Abstract

The Siberian Traps have been a reference object for geologists for many years in understanding the origin of Large Igneous Provinces on Earth. Data from high-magnesium rocks in its northern region have traditionally been used to create genetic models. However, the central and [...] Read more.

The Siberian Traps have been a reference object for geologists for many years in understanding the origin of Large Igneous Provinces on Earth. Data from high-magnesium rocks in its northern region have traditionally been used to create genetic models. However, the central and southern parts, consisting of the tholeiitic basaltic rocks (platform basalts, or typical traps), remain significantly unexplored, despite their important role in volcanic evolution within the province. This article presents new structural, mineralogical, and geochemical data from the tuff-lava sequences in the central regions of the Tunguska syneclise, i.e., along the Lower Tunguska River Valley and near Vanavara settlement in the Podkamennaya Tunguska Valley. The studied sections include pyroclastic rocks of the Korvunchansky Formation and overlaying basalts and tuffs of the Nidymsky and Kochechumsky Formations (Early Triassic, 251 Ma). Major and trace element analyses of 64 samples show that basalts from these formations are similar in composition, with MgO contents ranging from 4.2% to 7.8%. Trace element patterns exhibit negative Ta-Nb anomalies and positive Pb anomalies, which are typical of the Siberian platform basalts. Tuffs, on the other hand, differ from the basalts by having higher SiO₂ and K₂O contents and steeper rare earth element (REE) patterns. Isotopic analysis (Sr-Nd) confirms the difference between basalts and tuffs and suggests their origin from two distinct magma sources. The Nidymsky basalts have positive Ɛ_Nd values (+2.21 to +3.10), similar to those of the Morongovsky and Mokulaevsky basalts in the Norilsk area. Tuffs, on the other hand, exhibit negative Ɛ_Nd (−1.33 to −4.5) and elevated ⁸⁷Sr/⁸⁶Sr (>0.706), in comparison with the basalts (0.704–0.706). Geological observations reveal that pyroclastic rocks play a significant role at the initial stage of volcanic activity. The main result of this study is that tuffs from the Korvunchansky and Khakanchansky Formations (in the south and north of the province, respectively) are identical in their geochemical characteristics. This similarity suggests the existence of a single pyroclastic cover, closed in composition to Lower crust, over the Siberian platform. These pyroclastic rocks mark the beginning of trap magmatism in the Siberian province, rather than picrites, as suggested by the plume model. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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26 pages, 15116 KB

Open AccessArticle

Fine and Ultrafine Gold Mineralization in the Alluvial Fan Deposits of the Irgaity River, SE Kazakhstan

by Gulnara Omarova, Alla Dolgopolova, Saltanat Assubayeva, Alexander Tretyakov, Valeriy Peregudov, Reimar Seltmann, Cindy Broderick, Edgar Alejandro Cortes-Calderon, Kuanysh Togizov, Symbat Tugambay, Marat Anuarbek and Marina Mizernaya

Minerals 2026, 16(8), 853; https://doi.org/10.3390/min16080853 - 19 Aug 2026

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Abstract

Gold in the coarse-grained alluvial sediments of the Irgaity placer deposit (Kazakhstan) occurs predominantly as finely dispersed particles associated with mineral matrices, which limits the efficiency of conventional recovery methods. The proposed processing flowsheet demonstrated that thermal pre-treatment is an effective approach for [...] Read more.

Gold in the coarse-grained alluvial sediments of the Irgaity placer deposit (Kazakhstan) occurs predominantly as finely dispersed particles associated with mineral matrices, which limits the efficiency of conventional recovery methods. The proposed processing flowsheet demonstrated that thermal pre-treatment is an effective approach for enhancing ultrafine gold recovery, achieving an overall recovery of 86% from the treated concentrate. The Tescan TIMA “Bright Phase Search” workflow, optimized for gold detection by applying a minimum BSE brightness threshold of 75% and an Au phase filter calibrated using a gold standard, successfully identified gold-bearing grains within the analyzed mounts. Further mineralogical investigations revealed that gold particles ≤10 μm occur as native gold and Au-Ag-As-bearing phases, with silver content reaching up to 14 wt.% in some coarser grains. The significant association of silver with gold-bearing particles indicates the potential for incorporating silver recovery into the processing flowsheet, thereby improving the overall economic value of the deposit. Despite the low average gold grade (0.3–0.4 g/t), the large dimensions of the Irgaity placer deposit (approximately 12 km long, 1.5 km wide, and 60–70 m thick) suggest the presence of a substantial large-volume mineral resource. The combination of extensive mineralized sediments and high recovery achieved through thermal activation supports the potential economic viability of the deposit and warrants further evaluation of its development potential. Full article

(This article belongs to the Section Mineral Deposits)

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19 pages, 19753 KB

Open AccessArticle

Soil Thermomagnetic-Fraction Geochemistry for Prioritizing Concealed Ni-Cu Sulfide Exploration Targets: A Case Study from the Jing’erquan Area, Beishan, NW China

by Jianzhou Yang, Zhenliang Wang, Wenli Su, Jianweng Gao, Keqiang Zhao, Yangang Fu, Yongwen Cai, Jingjing Gong, Yong Li, Lujun Lin and Zhuang Duan

Minerals 2026, 16(8), 852; https://doi.org/10.3390/min16080852 - 18 Aug 2026

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Abstract

Thermomagnetic-fraction geochemistry has shown promise beneath transported cover, but area-scale applications rarely combine explicit element-association analysis, statistical robustness tests and transparent target prioritization. We evaluate this workflow in the largely covered Jing’erquan Ni-Cu metallogenic area using 985 soil samples collected over approximately 140 [...] Read more.

Thermomagnetic-fraction geochemistry has shown promise beneath transported cover, but area-scale applications rarely combine explicit element-association analysis, statistical robustness tests and transparent target prioritization. We evaluate this workflow in the largely covered Jing’erquan Ni-Cu metallogenic area using 985 soil samples collected over approximately 140 km² at an average spacing of about 300 m (7.0 samples km⁻²). After removal of pre-existing strongly magnetic grains, 100 g aliquots were heated under oxygen-limited conditions at 650 °C for 45 min, and the newly generated magnetic fraction was separated at an instrument-current setting of 1 A. Twelve indicators were analyzed using descriptive statistics, correlation analysis, hierarchical clustering, principal component analysis (PCA), spatial clustering and a three-term composite score. Four rotated factors explain 75.1% of the variance; Cr and Ni load at 0.95 on F2, while TFe₂O₃, Zn, Co and Cu covary on F1. Pearson–Spearman matrix agreement (r = 0.990), winsorized-versus-original Pearson agreement (r = 0.999), and PCA factor-congruence coefficients (>0.998) show that the principal associations are not controlled by the largest Cu, Ni or Cr values. Alternative composite weights retain all eight named follow-up targets, although internal ranking changes when Cu is emphasized. Among them, JQ-1–JQ-4 are assigned high follow-up priority by the expert-informed score. The coincidence of JQ-1 with the known Jing’erquan Ni-Cu mining area provides an internal plausibility check for the workflow, whereas JQ-2–JQ-8 remain unverified follow-up targets. These results show that the thermomagnetic-fraction dataset delineates multielement surface geochemical anomalies in covered terrain and can serve as a complementary screening tool for subsequent Ni-Cu exploration. Full article

(This article belongs to the Section Mineral Exploration Methods and Applications)

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27 pages, 30843 KB

Open AccessArticle

Process Mineralogy of a Kuroko-Type VMS Deposit: Influence of Ore Texture on Chalcopyrite Liberation

by Ercan Sahinoglu, Kadir Karaman, Bahrican Ar and Yunus Iskender

Minerals 2026, 16(8), 851; https://doi.org/10.3390/min16080851 - 18 Aug 2026

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Abstract

Process mineralogy provides valuable information for understanding the mineralogical and textural characteristics of volcanogenic massive sulfide (VMS) deposits and their influence on mineral liberation. This study investigates the relationship between ore texture and chalcopyrite liberation in massive and stockwork/disseminated copper ore samples from [...] Read more.

Process mineralogy provides valuable information for understanding the mineralogical and textural characteristics of volcanogenic massive sulfide (VMS) deposits and their influence on mineral liberation. This study investigates the relationship between ore texture and chalcopyrite liberation in massive and stockwork/disseminated copper ore samples from a Kuroko-type VMS deposit in the Eastern Black Sea Region of Türkiye. Whole-rock mineralogy, textures, and mineral intergrowth relationships were characterized using X-ray diffraction (XRD), reflected-light ore microscopy, and field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (FE-SEM/EDS) mapping. Both ore types contain chalcopyrite, pyrite, sphalerite, and galena as the main valuable minerals, with quartz as the predominant gangue mineral. However, they show distinct textural characteristics. In the massive ore, chalcopyrite occurs as fine-grained aggregates filling fractures in cataclastic pyrite and commonly forms complex intergrowths with adjacent sulfides. In contrast, the stockwork/disseminated ore exhibits a more dispersed sulfide distribution within a quartz-rich matrix. Liberation analyses conducted across six particle size fractions, ranging from −600 + 500 to −38 µm, demonstrate that chalcopyrite liberation increases as particle size decreases. The stockwork/disseminated ore consistently exhibits higher liberation than the massive ore across all size fractions. The highest liberation values were achieved in the −38 µm fraction, reaching 98% for the stockwork/disseminated ore and 90% for the massive ore. FE-SEM/EDS mapping confirms that micron-scale sulfide intergrowths in the massive ore limit complete liberation and contribute to its lower liberation efficiency. These findings highlight the influence of ore texture on chalcopyrite liberation and provide useful geometallurgical information for optimizing the grinding and beneficiation of Kuroko-type VMS ores. Full article

(This article belongs to the Special Issue Process Mineralogy, Plant Practice and Developments in Mineral Processing, 2nd Edition)

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26 pages, 29858 KB

Open AccessArticle

Carbon and Oxygen Isotope Enrichment Characteristics and Formation Mechanism of Carbonate Cements in Chang 8 Tight Sandstone Reservoir, Jiyuan Area, Ordos Basin

by Yue Cai, Qingyu Yang, Aihua Guo, JinLiang Zhang and Tingting Fan

Minerals 2026, 16(8), 850; https://doi.org/10.3390/min16080850 - 18 Aug 2026

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Abstract

To elucidate the formation mechanisms of carbonate cement in the Chang 8 tight sandstone reservoir of the Upper Triassic Yanchang Formation (Jiyuan Area), the types, paragenetic stages, and genesis of the cement were investigated via thin-section petrography, carbon–oxygen isotope analysis, and fluid inclusion [...] Read more.

To elucidate the formation mechanisms of carbonate cement in the Chang 8 tight sandstone reservoir of the Upper Triassic Yanchang Formation (Jiyuan Area), the types, paragenetic stages, and genesis of the cement were investigated via thin-section petrography, carbon–oxygen isotope analysis, and fluid inclusion microthermometry. Results indicate two distinct generations of carbonate cement within the Chang 8 reservoir: early micritic calcite cement and late sparry to coarsely crystalline ferroan calcite cement. The late ferroan calcite cement exhibits δ¹³C_PDB values spanning from −7.02‰ to −12.51‰ and δ¹⁸O_PDB values ranging from −18.81‰ to −30.24‰. The early micritic calcite cement is interpreted to have precipitated from supersaturated alkaline pore fluids during the shallow burial stage (Stage A of early diagenesis) at the close of the Late Triassic. Conversely, the late ferroan calcite cement formed during the Early Cretaceous at temperatures between 100 °C and 110 °C, and its genesis is closely linked to organic-acid-related fluids. These findings elucidate the characteristics of carbonate cements across different stages and have significant implications for predicting the distribution of high-quality reservoirs and for providing guidance for future exploration and development. Full article

(This article belongs to the Section Mineral Exploration Methods and Applications)

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18 pages, 2925 KB

Open AccessArticle

Interfacial Mechanism of Microwave Pretreatment Enhanced Ilmenite Flotation—Based on OHA + HDPA Composite Collector System

by Rongxiang Liu, Yonglun Wang and Jie Li

Minerals 2026, 16(8), 849; https://doi.org/10.3390/min16080849 - 17 Aug 2026

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Abstract

Ilmenite is the core carrier of titanium resources in China. Conventional flotation systems generally have the problems of insufficient collector adsorption efficiency and limited separation index. Microwave pretreatment can strengthen the flotation process by activating the surface of minerals, but its regulation mechanism [...] Read more.

Ilmenite is the core carrier of titanium resources in China. Conventional flotation systems generally have the problems of insufficient collector adsorption efficiency and limited separation index. Microwave pretreatment can strengthen the flotation process by activating the surface of minerals, but its regulation mechanism on the interface properties of ilmenite and the adsorption behavior of collectors remains to be systematically elucidated. Based on the previous research on the flotation separation effect of the ‘OHA + HDPA composite collector + microwave pretreatment (power of 800 W and irradiation time of 180s)’ system, this paper uses the OHA + HDPA (mass ratio 3:1) composite system as the collector and uses surface tension, contact angle, Zeta potential, infrared spectroscopy and X-ray photoelectron spectroscopy, and other multi-scale complementary characterization methods to systematically study the effect of microwave activation on the wettability of ilmenite surface and the adsorption of collector interface. The results show that the wettability of ilmenite surface by microwaves presents a two-way regulation characteristic. In a pure water system, microwave activation increases the surface polar active sites, the water contact angle decreases from 48.44° to 46.65°, and the hydrophilicity is slightly enhanced. Under the action of the collector, microwaves promoted the directional adsorption and orderly arrangement of reagents, the contact angle of minerals increased to 85.24°, the adhesion work reached 0.560 J/m², and the surface hydrophobicity and solid–gas adhesion ability were significantly improved. Interfacial electrokinetic analysis showed that microwave activation enhanced the positive surface charge of ilmenite, and the isoelectric point shifted from pH 5.1 to alkaline to pH 6.3. In the range of pH 2–10, the Zeta potential of the sample after microwave treatment shifted more negatively, which was due to the synergistic enhancement of electrostatic attraction and chemical chelation sites. Microscopic characterization confirmed that the collector was attached to the surface of ilmenite in the form of chemical adsorption. Microwaves did not change the essential properties of adsorption but increased the adsorption capacity of the collector by 10.9%, and the adsorption layer was more compact and orderly. A mechanism analysis reveals that microwave irradiation induces the oxidation of surface Fe²⁺ to Fe³⁺, and its atomic proportion increases from 23.91% to 38.64%, which significantly enhances the chelation between the collector and the iron site and the stability of the chemical bond. At the same time, combined with the change of XPS coordination environment, it is speculated that microwaves can induce lattice distortion, change the coordination environment of titanium atoms, increase the proportion of Ti-O-Fe bridge oxygen structure, increase the unsaturated titanium active site, and strengthen the coordination between the collector and the titanium site. The synergistic activation of iron–titanium multi-sites together enhances the adsorption strength and adsorption capacity of the collector. This study can provide theoretical support at the interface chemical level for the development of high-efficiency ilmenite flotation process. Full article

(This article belongs to the Section Mineral Processing and Extractive Metallurgy)

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33 pages, 18686 KB

Open AccessArticle

Integrated Approach to Paleontological and Geochemical Data of the Upper Campanian–Maastrichtian Harami Formation (Elazığ, Eastern Türkiye)

by Sibel Kayğılı, Ercan Aksoy and Mehmet Özkul

Minerals 2026, 16(8), 848; https://doi.org/10.3390/min16080848 - 17 Aug 2026

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Abstract

The aim of this study is to determine the age and depositional environment of the Harami Formation through an integrated interpretation of XRF, ICP-MS, SEM-EDS, stable isotope, and radioactive isotope analysis results and findings of larger benthic foraminifera. Findings from the authors’ previous [...] Read more.

The aim of this study is to determine the age and depositional environment of the Harami Formation through an integrated interpretation of XRF, ICP-MS, SEM-EDS, stable isotope, and radioactive isotope analysis results and findings of larger benthic foraminifera. Findings from the authors’ previous studies regarding the characteristics of larger benthic foraminifera were utilized; geochemical analysis results were obtained for the first time in this study. The mean ⁸⁷Sr/⁸⁶Sr values are generally consistent with the ages determined from the larger benthic foraminifera. The analysis results and Y/Ho values indicate that CaO is the dominant component, while negative Ce and positive Eu anomalies are indicative of a low-grade diagenetic effect. The absence of hydrothermal activity in the depositional environment and the proximity of the values to those of seawater are supported by the Y/Ho and Eu/Sm ratios. Similarly, to the larger benthic foraminifera content that indicates the Harami Formation was deposited in a shallow, oxic environment, the trace element ratios (V/Cr and V/V+Ni) and slightly negative Ce anomalies also support deposition in an oxic environment, while the Sr/Ba and Sr/Rb analysis results indicate a shallow marine environment. The analysis results further indicate that the depositional environment ranged from warm-temperate to arid conditions. A decrease in mean temperature is observed from the late Campanian to the early Maastrichtian, with an increase from the early Maastrichtian to the late Maastrichtian. Full article

(This article belongs to the Special Issue From Microbes to Minerals: Geochemical Signatures of Bacterial and Algal Sedimentary Systems)

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25 pages, 84309 KB

Open AccessArticle

Characteristics Investigation and Sequential Joint Inversion of Potential Field Vector Components

by Songlin Pan, Jun Wang, Yuan Fang and Jianyu Li

Minerals 2026, 16(8), 847; https://doi.org/10.3390/min16080847 - 17 Aug 2026

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Abstract

Recent advances in measurement techniques have greatly improved the accessibility of potential field vector data which contain richer directional information than conventional scalar data for high-precision localization of subsurface ore bodies. Nevertheless, the inversion characteristics of individual vector components remain poorly understood, and [...] Read more.

Recent advances in measurement techniques have greatly improved the accessibility of potential field vector data which contain richer directional information than conventional scalar data for high-precision localization of subsurface ore bodies. Nevertheless, the inversion characteristics of individual vector components remain poorly understood, and the effective integration of multi-vector components is still limited. To fulfill these gaps, this study first conducts a series of model experiments to systematically analyze the characteristics exhibited by each vector component. Subsequently, an iterative joint inversion scheme for comprehensive utilization of different vector components is proposed using the sequential strategy. Based on synthetic and real-data tests, it reveals that the horizontal X- and Y-components are most sensitive to sources extending along their respective axes, whereas the vertical Z-component, although beneficial for improving vertical resolution, exhibits a relatively weak anomaly amplitude. Most importantly, the proposed joint inversion method successfully integrates the complementary features of individual components, leading to marked improvements in inversion accuracy and source resolution, which provides a reliable tool for identifying concealed ore bodies, refining ore-body delineation, and prioritizing mineral exploration targets. Full article

(This article belongs to the Special Issue Advanced Methods of Inversion of Potential Field Data for Mineral Exploration)

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16 pages, 62972 KB

Open AccessArticle

Ancient Crustal Signatures in Mesozoic Magmatic Rocks of the Gan–Hang Belt: Zircon U-Pb Age and Trace Element Evidence from a Microdiorite Dike in Jiangshan, South China

by Junfeng Dai, Peng Zhang and Fuzong Li

Minerals 2026, 16(8), 846; https://doi.org/10.3390/min16080846 - 17 Aug 2026

Viewed by 552

Abstract

Geochronological investigation and geochemical tracing of xenocrystic zircons entrained in magmatic rocks serve as effective approaches for directly unraveling the material composition and architectural framework of the deep-seated ancient continental crust. Here, we present an integrated petrological, zircon petrographic, U-Pb geochronological, and trace [...] Read more.

Geochronological investigation and geochemical tracing of xenocrystic zircons entrained in magmatic rocks serve as effective approaches for directly unraveling the material composition and architectural framework of the deep-seated ancient continental crust. Here, we present an integrated petrological, zircon petrographic, U-Pb geochronological, and trace elemental study of a microdiorite dike from the Jiangshan area within the Gan–Hang tectonic belt, which is a key suture zone between the Yangtze and Cathaysia Blocks. Four distinct zircon types are recognized. Type I (2528 ± 21 Ma) is a metamorphic zircon that is derived from eclogite-facies metamorphism of a Neoarchean basement, revealing the existence of a Neoarchean continental crust in the deep South China Block. Types II (848 ± 53 Ma) and III (481 ± 93 Ma) are magmatic zircons representing captured Neoproterozoic and Early Paleozoic magmatic rocks, respectively. Type IV (137 ± 8.4 Ma) occurs as an overgrowth on its inherited cores and records the emplacement age of the microdiorite dike. Trace element compositions of Early Cretaceous zircons (type IV) show low Nb/Hf and elevated Th/Nb ratios, consistent with a magmatic arc setting. Combined with petrographic evidence of quartz xenocrysts and the diversity of captured zircons, we propose that the parental magma originated from partial melting of the subcontinental lithospheric mantle induced by slab-derived fluid flux, with the subsequent assimilation of diverse crustal materials during its ascent. This study not only constrains the Early Cretaceous arc magmatism in response to Paleo-Pacific Plate subduction but also provides evidence for Neoarchean crustal relics in the deep subsurface of the South China Block, with important implications for the deep compositional architecture and tectono-magmatic evolution of South China. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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28 pages, 5882 KB

Open AccessArticle

Compound-Specific Carbon Isotope Decoupling in the Çıralı (Yanartaş) Ophiolitic H₂–CH₄ System: Constraints on Multistage Gas Evolution in the Tekirova Peridotite, SW Türkiye

by Murat Şentürk

Minerals 2026, 16(8), 845; https://doi.org/10.3390/min16080845 - 16 Aug 2026

Viewed by 554

Abstract

The Çıralı (Yanartaş) gas seepage system in the Tekirova Peridotite, SW Türkiye, is an ophiolitic H₂–CH₄ system associated with serpentinized ultramafic rocks and fault-controlled pathways. This study evaluates molecular compositions, C₁–C₃ compound-specific carbon isotope data, and methane [...] Read more.

The Çıralı (Yanartaş) gas seepage system in the Tekirova Peridotite, SW Türkiye, is an ophiolitic H₂–CH₄ system associated with serpentinized ultramafic rocks and fault-controlled pathways. This study evaluates molecular compositions, C₁–C₃ compound-specific carbon isotope data, and methane hydrogen isotope compositions from four newly sampled gas outlets together with previously published data for which the full parameter set is available. The new samples contain 85.5–91.6% CH₄ and 2.6–5.3% H₂, with δ¹³C-CH₄ values of −7.3 to −4.4‰ and δ²H-CH₄ values of −121 to −104‰. The C₁–C₂ isotope reversal index (RI₁₂) ranges from +13.6 to +14.5‰, whereas the C₂–C₃ isotope proximity index (PI₂₃) ranges from 0.2 to 1.3‰. These values indicate the clear isotopic decoupling of methane from ethane and propane, whereas the C₂–C₃ pair shows comparatively small isotopic differences. The same relative pattern occurs at all four outlets, indicating consistency between samples. The results are consistent with a multistage model in which C₂+ components are compatible with a thermogenic contribution, whereas methane may have been affected by serpentinization-related H₂ input, fracture-controlled flow, and shallow ophiolitic modification. Catalytic CO₂ hydrogenation is evaluated not as a demonstrated field-scale process but as a hypothesis requiring testing in chromitite–serpentinite-related microenvironments. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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25 pages, 17517 KB

Open AccessArticle

Genesis of the Giant Aynak Copper Deposit, Afghanistan: Constraints from Sulphide Geochemistry (ICP-MS) and Fluid Inclusions

by Hamidullah Waizy, Norman R. Moles and Martin P. Smith

Minerals 2026, 16(8), 844; https://doi.org/10.3390/min16080844 - 15 Aug 2026

Viewed by 1084

Abstract

Located 30 km south–southeast of Kabul in Logar province, Aynak is the largest and best-known copper orebody in Afghanistan. The deposit is hosted by the Loy Khwar Formation, a Neoproterozoic–Cambrian metasedimentary sequence of dolomite marble, carbonaceous quartz schist and quartz–biotite–dolomite schist. The primary [...] Read more.

Located 30 km south–southeast of Kabul in Logar province, Aynak is the largest and best-known copper orebody in Afghanistan. The deposit is hosted by the Loy Khwar Formation, a Neoproterozoic–Cambrian metasedimentary sequence of dolomite marble, carbonaceous quartz schist and quartz–biotite–dolomite schist. The primary ore minerals are chalcopyrite and bornite, with less abundant pyrite and minor cobaltite, chalcocite, pyrrhotite, sphalerite and molybdenite. Sulphides occur as bedded laminae and disseminations, in metamorphic segregations, and in syn- to post-metamorphic cross-cutting veins. Building on the mineralogical, lithogeochemical and sulphur isotope framework established by Waizy et al. (2020), ICP-MS analyses of sulphide-rich separates from Central and Western Aynak (n = 31) were undertaken to characterise trace-element distributions, evaluate possible metal sources, and further constrain the genetic model of the deposit. Co and As enrichment in chalcopyrite-dominant samples is consistent with cobaltite, whereas Co enrichment in the absence of arsenic suggests the possible presence of carrollite. Fluid inclusion analyses of secondary quartz-hosted inclusions indicate interaction between the Aynak deposits and saline aqueous fluids (32 to 47 equivalent wt% NaCl) at minimum P-T conditions of ~100–200 MPa and 300 °C. It is uncertain whether these fluid parameters relate to primary copper transport and deposition, or to remobilisation during metamorphism. Nevertheless, comparison with analogous sediment-hosted copper deposits suggests that highly saline basinal brines played an important role in the formation and evolution of the deposit. Occurrences of scapolite provide additional evidence for a model of brine-related mineralisation. Together with previously published mineralogical, lithogeochemical and sulphur isotope evidence, these findings support a sedimentary–diagenetic origin for the Aynak copper deposit that is broadly comparable with sediment-hosted stratiform copper systems of the Central African Copperbelt. Full article

(This article belongs to the Special Issue Formation and Characteristics of Sediment-Hosted Ore Deposits)

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21 pages, 9499 KB

Open AccessArticle

Formation Mechanism and Color Genesis of the Yiyuan Jade in Luanchuan, Eastern Qinling (Central China): Implications for the Provenance Tracing of Ancient Jade Artifacts

by Hao Lu, Jun Chai, Wanlu Fu, Juncai Ma and Xuanshuai Wang

Minerals 2026, 16(8), 843; https://doi.org/10.3390/min16080843 - 15 Aug 2026

Viewed by 256

Abstract

The Yiyuan jade from Luanchuan County, Henan Province (Central China), has been known since the Neolithic period and provides a scientific reference for tracing the provenance of jade artifacts from nearby Neolithic sites. In this study, the mineralogical characteristics and color genesis of [...] Read more.

The Yiyuan jade from Luanchuan County, Henan Province (Central China), has been known since the Neolithic period and provides a scientific reference for tracing the provenance of jade artifacts from nearby Neolithic sites. In this study, the mineralogical characteristics and color genesis of the Yiyuan jade were investigated using petrography, XRD, SEM–EDS, FTIR, UV–Vis–NIR, and EPR spectroscopy. The jade occurs in four color varieties and is petrologically classified as serpentine–bearing dolomitic marble formed by Neoproterozoic gabbroic magma intrusion and subsequent low–temperature alteration. The color variations correspond to distinct mineral assemblages. White jade is dominated by calcite and dolomite; bluish–black jade by antigorite, clinochlore, and chamosite; bluish–white jade contains intermediate proportions of these phases; and green jade consists mainly of epidote and actinolite. The bluish color intensity shows a quantitative correlation with the green mineral content. Bluish–white appears when antigorite and clinochlore together account for 5%–40%, bluish–black when they exceed 40%, and bluish–gray when chamosite exceeds 10%. The bluish–black coloration is controlled by the dense fibrous interwoven microstructure of antigorite rather than by Fe or other elemental chromophores. These distinctive features serve as diagnostic criteria for identifying bluish–black jade materials from Neolithic sites in the Luanchuan region. Full article

(This article belongs to the Section Crystallography and Physical Chemistry of Minerals & Nanominerals)

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4 pages, 134 KB

Open AccessEditorial

Editorial for Special Issue “Element Enrichment and Gas Accumulation in Black Rock Series”

by Tingshan Zhang, Chang’an Shan, Lei Chen and Xi Zhang

Minerals 2026, 16(8), 842; https://doi.org/10.3390/min16080842 - 14 Aug 2026

Viewed by 524

Abstract

The enrichment of elements in black shale and the accumulation of natural gas exhibit a complex, coupled relationship that spans multiple critical geological stages, from sedimentary organic matter preservation and diagenetic evolution to organic matter pyrolysis and gas generation [...] Full article

(This article belongs to the Special Issue Element Enrichment and Gas Accumulation in Black Rock Series)

32 pages, 35381 KB

Open AccessArticle

U-Pb Zircon Geochronology and Trace-Element Geochemistry of Attabad Lake and Nomal Village Granitoids from the Karakoram and Kohistan Batholiths, NW Pakistan: Local Constraints on Magmatic Evolution

by Muhammad Zeeshan Abbasi, Wanyi Zhang, Muhammad Saleem Mughal, Naveed Khan, Syed Wajee Ul Hassan Gillani, Akang Tian and Chengjun Zhang

Minerals 2026, 16(8), 841; https://doi.org/10.3390/min16080841 - 14 Aug 2026

Viewed by 417

Abstract

The timing and nature of the tectonic transition from Neo-Tethyan subduction to India-Asia collision along the NW Himalaya remain debated, particularly regarding the relationship between continental arc and post-collisional magmatism in the Karakoram and Kohistan batholiths. We present zircon U-Pb ages, whole-rock geochemistry, [...] Read more.

The timing and nature of the tectonic transition from Neo-Tethyan subduction to India-Asia collision along the NW Himalaya remain debated, particularly regarding the relationship between continental arc and post-collisional magmatism in the Karakoram and Kohistan batholiths. We present zircon U-Pb ages, whole-rock geochemistry, and zircon trace-element data from three granitoid samples from the Attabad Lake area (Karakoram Batholith) and the Nomal area (Kohistan Batholith). Zircon U-Pb dating yields crystallization ages of 103.4 ± 1.7 Ma for the Karakoram diorite, and 46.10 ± 0.79 Ma and 43.59 ± 0.88 Ma for the Kohistan enclave and host quartz monzonite, respectively. The Karakoram diorite shows LREE enrichment [(La/Yb)_N = 5.93–78.52] and positive zircon Ce anomalies (Ce/Ce* = 9.00–18.70), features broadly consistent with crystallization from an oxidized, subduction-related magma. In contrast, the Kohistan quartz monzonite exhibits elevated SiO₂ (65.01–66.35 wt%), low Mg# (25.9–27.2), and a flat to slightly negative Eu anomaly (Eu/Eu* = 0.94), which may reflect crustal melting during post-collisional extension. The enclave displays mantle-like signatures with high Sr (1623 ppm) and a positive Eu anomaly (Eu/Eu* = 1.14), suggesting a mafic recharge event. Zircon Th/U ratios (>0.1) and magmatic REE patterns support a magmatic origin for the dated zircons. These results are compatible with, but do not independently establish, previously proposed regional models. They provide additional local constraints that point to spatially heterogeneous magmatic evolution along the NW Himalayan syntaxis, with continental arc magmatism in the Attabad Lake area during the mid-Cretaceous and a transition to post-collisional extension in the Nomal area during the Eocene. Full article

(This article belongs to the Special Issue Continental Crust Evolution in Collisional and Accretionary Orogens: Petrological, Tectonic and Metallogenic Implications)

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23 pages, 4600 KB

Open AccessArticle

Medium-Term Planning of Mining Complexes with Explicit Shovel Tracking and Processing Plant Uncertainty

by Liam Findlay and Roussos Dimitrakopoulos

Minerals 2026, 16(8), 840; https://doi.org/10.3390/min16080840 - 14 Aug 2026

Viewed by 258

Abstract

Simultaneous and stochastic optimization of open-pit mining complexes at the medium-term level aims to maximize expected profits, manage technical risk for integrated value chains, and enhance the operational feasibility of the long-term plan while still meeting its targets to achieve long-term value. To [...] Read more.

Simultaneous and stochastic optimization of open-pit mining complexes at the medium-term level aims to maximize expected profits, manage technical risk for integrated value chains, and enhance the operational feasibility of the long-term plan while still meeting its targets to achieve long-term value. To address two key operational feasibility challenges over a twelve-month horizon, the proposed framework integrates two features that provide a more detailed operational evaluation during decision-making than existing methods. The first involves explicit tracking of shovel movements to align optimized extraction sequences with the operational capabilities of loading equipment. The second uses high-order simulation to produce probability distributions for processing plant responses based on geometallurgical properties of the material being scheduled and selected operating modes. To efficiently optimize schedules with this detailed evaluation, a solution method is proposed using an online machine learning model to rank moves in a metaheuristic search procedure. The framework is demonstrated using a gold mining complex and results show realistic extraction sequences with an increase in metal production and cashflow when compared to a regression-based processing model. Full article

(This article belongs to the Special Issue Geometallurgy Applied to Mine Planning)

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24 pages, 3227 KB

Open AccessArticle

Multi-Proxy Reconstruction of Organic Matter Accumulation and Its Controls in Oligocene–Pliocene Lacustrine Shales, Western Qaidam Basin (China)

by Shangkun Li, Xueyun Ma, Zhifu Wei, Yongli Wang, Pengyuan Zhang, Gen Wang, Kaikang Liang, Kebin Wei and Jianzhen Chen

Minerals 2026, 16(8), 839; https://doi.org/10.3390/min16080839 - 14 Aug 2026

Viewed by 572

Abstract

Low-TOC saline lacustrine shales are widespread in Cenozoic basins of northwestern China and Central Asia, yet their organic matter accumulation (OMA) mechanisms under arid, saline conditions remain poorly understood. We analyzed TOC, major and trace elements, and C–O isotopes in 64 core samples [...] Read more.

Low-TOC saline lacustrine shales are widespread in Cenozoic basins of northwestern China and Central Asia, yet their organic matter accumulation (OMA) mechanisms under arid, saline conditions remain poorly understood. We analyzed TOC, major and trace elements, and C–O isotopes in 64 core samples from eight wells in the western Qaidam Basin, and reconstructed terrigenous input, weathering intensity, paleoproductivity, redox conditions, and salinity. TOC ranges from 0.04% to 1.10% (mean 0.32%), with a statistically significant upward trend from the Shangganchaigou (mean 0.25%) to the Shangyoushashan Formation (mean 0.43%) (Kruskal–Wallis, p = 0.010). The climate was dry–cold with progressive aridification (increasing δ¹⁸O and Sr/Ba). The water body evolved from closed, strongly reducing, and unstable to more open, weakly reducing, and increasingly saline. We propose that limited nutrient supply set a low baseline for organic enrichment. Weakened terrigenous dilution and enhanced water-column stability then drove the gradual TOC increase. This reveals that OMA can occur without concurrent productivity rise, sustained solely by long-term preservation improvement, offering new constraints for source rock evaluation in arid lacustrine basins. Full article

(This article belongs to the Special Issue Mineralogy, Geochemistry, and Sedimentary Geology of Lacustrine Basins, 2nd Edition)

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20 pages, 5312 KB

Open AccessArticle

Audio Magnetotelluric Data Denoising Using Improved K-Singular Value Decomposition Dictionary Learning: Application to Mining Areas with Strong Cultural Noise

by Haiyang Kuang, Xuejian Teng, Chao Fu, Jinfeng Yang and Fei Teng

Minerals 2026, 16(8), 838; https://doi.org/10.3390/min16080838 - 14 Aug 2026

Viewed by 283

Abstract

Audio magnetotelluric (AMT) sounding is an essential tool for mineral exploration and subsurface electrical structure imaging. However, persistent cultural noise can severely degrade AMT data quality, particularly in mining areas with strong anthropogenic interference. In this study, we introduce an improved K-Singular Value [...] Read more.

Audio magnetotelluric (AMT) sounding is an essential tool for mineral exploration and subsurface electrical structure imaging. However, persistent cultural noise can severely degrade AMT data quality, particularly in mining areas with strong anthropogenic interference. In this study, we introduce an improved K-Singular Value Decomposition (K-SVD) dictionary learning method for time-domain AMT data denoising, incorporating three key innovations: (1) automatic identification of noise-contaminated segments using local kurtosis; (2) adaptive dictionary initialization combining principal component analysis with Gaussian perturbation, which accelerates convergence and avoids local minima; and (3) online atom screening and updating to maintain the noise specificity of the learned atoms. The proposed method learns noise morphology directly from raw AMT data without requiring reference stations or external training datasets. Synthetic experiments demonstrate that the method more effectively suppresses square-wave and charge-discharge noise compared with wavelet thresholding methods and conventional K-SVD, while better preserving signal morphology. Field applications further show that it significantly enhances the quality of observed data and apparent resistivity-phase curves compared with the widely used robust estimation method. The proposed method provides an efficient, reference-free solution for AMT data denoising in mining areas with strong cultural noise. Full article

(This article belongs to the Special Issue Application of Electromagnetic Method in Studying Deep Tectonic and Mineralization Processes)

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17 pages, 10272 KB

Open AccessArticle

Biochar-Modified Iron Tailings for Cr(VI) Removal from Acid Mine Drainage

by Jie Liu, Wanren Zhang, Runjie Qin, Zhiyang Wang, Kanghui Ren and Peiqing Hu

Minerals 2026, 16(8), 837; https://doi.org/10.3390/min16080837 - 13 Aug 2026

Viewed by 345

Abstract

Iron tailings, the major solid waste generated during iron ore beneficiation, possess substantial resource potential, but their utilization remains limited. Although iron tailings can adsorb Cr(VI)-containing oxyanions, their aggregation in aqueous systems restricts adsorption kinetics, resulting in only 24.4% Cr(VI) removal at an [...] Read more.

Iron tailings, the major solid waste generated during iron ore beneficiation, possess substantial resource potential, but their utilization remains limited. Although iron tailings can adsorb Cr(VI)-containing oxyanions, their aggregation in aqueous systems restricts adsorption kinetics, resulting in only 24.4% Cr(VI) removal at an initial concentration of 30 mg/L. In this study, an economical biochar–iron tailings composite was synthesized via a one-step pyrolysis method, with biochar serving as a carbon framework to disperse iron tailings and enhance Cr(VI) removal. The composite achieved approximately 50% Cr(VI) removal at 30 mg/L, representing a significant improvement compared with raw iron tailings. In simulated acidic mine wastewater, under optimized conditions of pH 2, a dosage of 0.8 g/L, and 10 mg/L Cr(VI), the composite removed over 95% of Cr(VI) within 8 h and reached 99.95% removal after 24 h. These results demonstrate that biochar effectively alleviates iron tailings aggregation and improves adsorption performance while maintaining a relatively low treatment cost. This biochar–iron tailings composite provides a promising strategy for Cr(VI)-contaminated wastewater treatment and the high-value utilization of iron tailings. Full article

(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)

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25 pages, 4669 KB

Open AccessArticle

Mechanism Study on Deep Removal of Lattice Impurities from High-Purity Quartz by Chlorination Roasting

by Lin Liu, Hongzhao Liu, Jianguo Li, Tuaner Peng, Wei Wang, Fei Wang and Guangxue Liu

Minerals 2026, 16(8), 836; https://doi.org/10.3390/min16080836 - 13 Aug 2026

Cited by 1 | Viewed by 309

Abstract

High-temperature chlorination roasting is a critical technique for achieving ultra-high-purity quartz required in semiconductor, photovoltaic, and fiber-optic applications. However, the removal mechanisms of lattice-bound impurities remain poorly understood due to a lack of integrated thermodynamic and kinetic analysis. This study systematically investigates the [...] Read more.

High-temperature chlorination roasting is a critical technique for achieving ultra-high-purity quartz required in semiconductor, photovoltaic, and fiber-optic applications. However, the removal mechanisms of lattice-bound impurities remain poorly understood due to a lack of integrated thermodynamic and kinetic analysis. This study systematically investigates the removal behavior of seven key lattice impurities, namely Ti, Al, B, Fe, Li, Na, and K, during chlorination roasting using combined thermodynamic modeling and diffusion kinetics. Thermodynamic calculations reveal that carbonaceous reductants are indispensable for enabling spontaneous chlorination of substitutional impurities such as Ti, Al, and B, while alkali metals including Na, K, and Li can be effectively removed under HCl atmosphere at moderate temperatures. Kinetic analysis identifies solid-state diffusion through the SiO₂ lattice as the likely rate-determining step based on the modeling framework, with activation energies ranging from approximately 90 kJ/mol for Na⁺ to 400 kJ/mol for Ti⁴⁺. A significant diffusion crossover effect is observed, where high-activation-energy impurities exhibit exponential mobility gains above 1200 °C. An alkali-first, Al-follows coupled diffusion mechanism is elucidated for aluminum removal. Based on these findings, a temperature-staged, atmosphere-segmented roasting strategy is proposed. This work provides a quantitative mechanistic framework for deep impurity removal and offers practical guidance for overcoming the 4N8 purity bottleneck in high-purity quartz production. Full article

(This article belongs to the Special Issue Physicochemical Properties and Purification of Quartz Minerals, 2nd Edition)

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15 pages, 2765 KB

Open AccessArticle

Integrated Hydrometallurgical Recovery of Vanadium from Spent Petrochemical Catalysts for the Production of High-Purity Ammonium Metavanadate

by Nazigul Zhumakynbai, Feruza A. Berdikulova, Bagzhan G. Ondiris and Gauhar S. Sapargaliyeva

Minerals 2026, 16(8), 835; https://doi.org/10.3390/min16080835 - 13 Aug 2026

Viewed by 276

Abstract

An integrated hydrometallurgical process for the recovery of vanadium from spent petrochemical catalysts and the production of high-purity ammonium metavanadate (AMV) was developed and experimentally validated. Alkaline leaching of roasted vanadium-bearing catalysts resulted in vanadium extraction of 90%–95%, producing a solution containing 37.0 [...] Read more.

An integrated hydrometallurgical process for the recovery of vanadium from spent petrochemical catalysts and the production of high-purity ammonium metavanadate (AMV) was developed and experimentally validated. Alkaline leaching of roasted vanadium-bearing catalysts resulted in vanadium extraction of 90%–95%, producing a solution containing 37.0 g/L V₂O₅ together with phosphorus, sulfur, silicon, and molybdenum impurities. Two purification approaches, ion-exchange sorption and magnesium oxide treatment, were evaluated for impurity removal. Sorption using the macro porous anion-exchange resin Biolite 200U provided effective silicon removal but resulted in significant vanadium losses (up to 19.6%) due to co-sorption of vanadium and phosphorus. In contrast, magnesium oxide treatment at 70–80 °C reduced the phosphorus concentration from 0.39 to 0.04 g/L (approximately 90% removal) and completely removed silicon while limiting vanadium losses to less than 2.5%. Following purification, ammonium metavanadate was precipitated using ammonium chloride at a V₂O₅:NH₄Cl molar ratio of 1:2 and pH 8.8–9.0, achieving approximately 99% vanadium recovery. X-ray diffraction analysis confirmed the formation of single-phase NH₄VO₃ after solution purification, whereas precipitation from untreated solutions resulted in contamination by alumina-bearing phases. The proposed process provides an effective route for producing purified ammonium metavanadate suitable for subsequent conversion into metallurgical-grade V₂O₅. The ultimate goal of the proposed technology is the production of metallurgical-grade ferrovanadium (FeV80). Because AMV is thermally converted to V₂O₅ with a weight loss of approximately 24%–25%, phosphorus and sulfur concentrations in AMV must be maintained below approximately 0.04 wt.% to ensure compliance with the impurity requirements of FeV80 according to GOST 27130-94. Full article

(This article belongs to the Section Mineral Processing and Extractive Metallurgy)

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24 pages, 11137 KB

Open AccessArticle

Experimental Modeling of Mantle Metasomatic Processes Involving Carbon- and Sulfur-Bearing Agents in an Olivine–Siderite–Sulfur System at Early-Subduction Mantle Conditions

by Yuliya V. Bataleva and Yuri N. Palyanov

Minerals 2026, 16(8), 834; https://doi.org/10.3390/min16080834 - 12 Aug 2026

Viewed by 669

Abstract

During Precambrian subduction, banded iron formations (BIFs) may have represented an early significant input of carbonates and atmospheric sulfur into the lithospheric mantle, initiated the formation of carbonatite melts and probably triggered mantle metasomatic processes. Experimental modeling of the interaction of BIF-related metasomatic [...] Read more.

During Precambrian subduction, banded iron formations (BIFs) may have represented an early significant input of carbonates and atmospheric sulfur into the lithospheric mantle, initiated the formation of carbonatite melts and probably triggered mantle metasomatic processes. Experimental modeling of the interaction of BIF-related metasomatic agents with upper mantle rocks, under Archean subduction geotherm, was performed in the simplified olivine–siderite–sulfur system. Experiments were carried out at 6.3 GPa, temperature range of 1150–1450 °C and durations of 20–60 h, using a multi-anvil high-pressure apparatus of a “split-sphere” type. Interaction of Fe,Ni–olivine and siderite with sulfur melt leads to the formation of pyrrhotite + orthopyroxene + ferromagnesite ± magnetite assemblage (1150–1250 °C, 40–60 h), as well as generation of sulfide (1350–1450 °C) and carbonate–silicate melts (1450 °C, 20 h); in all experiments, dissolution of diamond seed crystals is observed. Redox conditions are estimated to approximately correspond to ƒO₂ ~ CCO + 0.5 log. units. We demonstrated that during experiments, sulfidation of Fe,Ni–olivine and siderite and redox dissociation of siderite took place. It was shown that indicators of these processes are (1) polycrystalline orthopyroxene + pyrrhotite and pyrrhotite + ferromagnesite aggregates, inheriting shape of olivine and siderite crystals, respectively; (2) orthopyroxene zoned crystals with pyrrhotite inclusions; (3) pyrrhotite with ferromagnesite inclusions and ferromagnesite with magnetite + pyrrhotite inclusions. The obtained results with certain limitations can be used to constrain processes of metasomatic alteration of upper mantle rocks by agents enriched in iron, sulfur, and carbon under relatively oxidizing conditions (ƒO₂ ~ CCO + 0.5 log. units). Full article

(This article belongs to the Section Crystallography and Physical Chemistry of Minerals & Nanominerals)

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24 pages, 10375 KB

Open AccessArticle

Prospecting Prediction Model and Target Delineation of “Dongchuan-Type” Copper Deposits in the SW Yangtze Block: A Case Study of the Shizishan Deposit, Yunnan Province

by Xiaofei Zhang, Junlu Wang, Hui Chen, Zhenshan Pang, Bing Yu, Guochao Chen and Xiatao Wu

Minerals 2026, 16(8), 833; https://doi.org/10.3390/min16080833 - 11 Aug 2026

Viewed by 674

Abstract

Amidst the intensification of strategic mineral exploration, the discovery of concealed and deep-seated deposits within covered areas and the peripheries of existing mines has become a critical challenge and a central focus of contemporary research. “Dongchuan-type” (DCT) copper deposits represent a key mineralization [...] Read more.

Amidst the intensification of strategic mineral exploration, the discovery of concealed and deep-seated deposits within covered areas and the peripheries of existing mines has become a critical challenge and a central focus of contemporary research. “Dongchuan-type” (DCT) copper deposits represent a key mineralization style within the SW Yangtze Block. However, significant exploration breakthroughs have stagnated over the past three decades. Consequently, advanced exploration prediction research is urgently required to guide deep-resource evaluation. Using the Shizishan copper deposit in the Yimen area as a representative case, this study applies the theory of “metallogenic geological body prediction” to construct a tripartite model encompassing “metallogenic geological bodies, metallogenic structures and structural planes, and metallogenic characteristic markers”. The Shizishan deposit is classified as a sedimentary-reformed type, characterized by multi-episodic mineralization involving initial sedimentary processes, non-magmatic hydrothermal activity, and subsequent structural-magmatic hydrothermal overprinting. Key metallogenic geological bodies include ore-bearing stratigraphic associations, basin-margin faults, NE-trending fold–fault systems, and deep-seated concealed intrusions. Metallogenic structural planes comprise primary ore-controlling surfaces, secondary fold-related structures, and potential deep-seated magmatic intrusive interfaces. Alteration patterns display a distinct vertical zonation: shallower levels show medium-to-low temperature hydrothermal processes (silicification, carbonatization, sericitization, and chloritization), whereas deeper portions reveal high-temperature magmatic–hydrothermal indicators, specifically skarnization and intense silicification. This study proposes that the integration of “stratigraphy + structures + concealed intrusions” should serve as the primary criterion for target screening in deep exploration. By integrating geophysical and geochemical datasets into this model, three promising exploration targets were delineated within the Yimen area. These findings provide a refined theoretical framework for large-scale prospecting of DCT. Full article

(This article belongs to the Special Issue Formation and Characteristics of Sediment-Hosted Ore Deposits)

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33 pages, 50265 KB

Open AccessArticle

3D Geological Model and Interpretation of Structural Evolution of the Masa Valverde VMS Deposit, Iberian Pyrite Belt (Spain)

by Mónica Arias, José-Manuel Macías, Antonia Cepedal, Mercedes Fuertes, Fernando Cortes, Josep Poblet, Daniel Arias, Pablo Gumiel and Agustin Martin-Izard

Minerals 2026, 16(8), 832; https://doi.org/10.3390/min16080832 - 11 Aug 2026

Viewed by 838

Abstract

This study presents a 3D geological model and structural interpretation of the Masa Valverde volcanogenic massive sulfide (VMS) deposit in the Iberian Pyrite Belt. The deposit is hosted by felsic porphyritic volcanic rocks, volcanic tuffs, and black shales. A 3D geological model of [...] Read more.

This study presents a 3D geological model and structural interpretation of the Masa Valverde volcanogenic massive sulfide (VMS) deposit in the Iberian Pyrite Belt. The deposit is hosted by felsic porphyritic volcanic rocks, volcanic tuffs, and black shales. A 3D geological model of the orebodies and host rocks, constructed from 145 drill-core logs, allowed us to build 16 cross-sections spaced 100 m apart and constrain the mineralization geometry and its structural evolution. Mineralization formed during Early Carboniferous transtensional tectonics within an extensional basin, where an extensional duplex structure controlled the development of the primary massive sulfide body and its associated stockwork. Subsequent counterclockwise rotation of the principal stress axes reactivated extensional faults as reverse faults during tectonic inversion. This deformation strongly modified the VMS system through buttressing, generating extensive open spaces, and promoting the brecciation and recrystallization of both the stockwork and massive sulfides. These processes produced a new paragenesis dominated by chalcopyrite and sphalerite, with minor galena among other minerals, which cemented the breccias, partially replaced earlier mineral assemblages, and filled open fractures. The resulting Cu-Zn enrichment, spatially associated with buttressed zones, provides new insights into ore remobilization with direct implications for the development of the ongoing underground mine. Full article

(This article belongs to the Special Issue Iberian Pyrite Belt: Advances in Mineral Exploration, Mineral Deposits and Geological Processes)

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26 pages, 18413 KB

Open AccessArticle

Multiple-Stage Mineralization at the Bailingshan Volcanic-Hosted Iron Deposit, Xinjiang, NW China: Constraints from Garnet U-Pb and Amphibole Ar-Ar Geochronology and Garnet Geochemistry

by Fengmei Chai, Qingpeng Meng, Mengjing Xu, Dongmei Qi and Haitao Zhao

Minerals 2026, 16(8), 831; https://doi.org/10.3390/min16080831 - 11 Aug 2026

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Abstract

The Bailingshan submarine volcanic-hosted iron deposit in the Eastern Tianshan provides an opportunity to investigate skarn hydrothermal evolution and high-grade Fe mineralization. This study integrates garnet petrography, in situ major- and trace-element analyses, garnet U–Pb geochronology, and amphibole ⁴⁰Ar/³⁹Ar geochronology. [...] Read more.

The Bailingshan submarine volcanic-hosted iron deposit in the Eastern Tianshan provides an opportunity to investigate skarn hydrothermal evolution and high-grade Fe mineralization. This study integrates garnet petrography, in situ major- and trace-element analyses, garnet U–Pb geochronology, and amphibole ⁴⁰Ar/³⁹Ar geochronology. Four generations of grossular–andradite garnet (Grt1–Grt4) exhibit systematic textural and compositional variations reflecting the combined effects of crystal-chemical controls, hydrothermal fluid composition, and fluid–rock interaction. U–Pb dating of Grt2 yields 331.8 ± 8.9 Ma, linking the principal skarn formation and Fe mineralization stage to Early Carboniferous volcanism. Amphibole ⁴⁰Ar/³⁹Ar dating yields 302.6 ± 2.4 Ma, constraining a younger, localized hydrothermal overprint with limited Fe addition. Integrated evidence indicates that the Bailingshan deposit formed through a multistage, episodic hydrothermal evolution involving initial skarn formation, the principal Grt2–magnetite stage, subsequent shifts in hydrothermal conditions recorded by Grt3 and Grt4, and a localized late-stage hydrothermal overprint. These results not only constrain the timing of mineralization and subsequent overprinting but also offer valuable exploration implications for high-grade Fe mineralization in the Eastern Tianshan and comparable submarine volcanic-hosted iron districts. Full article

(This article belongs to the Special Issue Large Igneous Provinces: Petrogenesis, Mineralization, and Environmental Impact)

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21 pages, 18811 KB

Open AccessArticle

Fractal Parameters as Spatial Proxies to Reveal Cu Mineralization Spatial Patterns of Pulang Porphyry Deposit, Yunnan Province, Southwest China

by Xiaochen Wang, Yuqi Liang, Qiangqiang Jiang and Shuai Leng

Minerals 2026, 16(8), 830; https://doi.org/10.3390/min16080830 - 11 Aug 2026

Viewed by 282

Abstract

The variation features of metallic element grades can reflect the enrichment level of mineral deposits. Thus, quantitative characterization of the spatial patterns of metallogenic elements is fundamental to studying ore-forming processes and implementing mineral exploration. This study applies fractal theory and self-developed MATLAB [...] Read more.

The variation features of metallic element grades can reflect the enrichment level of mineral deposits. Thus, quantitative characterization of the spatial patterns of metallogenic elements is fundamental to studying ore-forming processes and implementing mineral exploration. This study applies fractal theory and self-developed MATLAB computational scripts to process Cu grade datasets from 28 drillholes within the Pulang porphyry copper deposit, Yunnan Province. Both rescaled range (R/S) analysis and correlation integral methods were applied to clarify the spatial patterns of Cu grades in drill-cores. The calculated Hurst exponents ranged from 0.510 to 0.636, which demonstrated the persistent variation of Cu grades along the vertical direction of drillholes. This work further explored the correlation between Cu mineralization and fluctuations in correlation dimension (D_C), with D_C values spanning 0.011–2.873. Results indicate steep fractal gradient zones host high-grade copper ore bodies, and fractal dimension is a robust indicator to trace the migration of hydrothermal fluids. The Hurst exponents of Cu grade sequences correlate strongly with mineralization intensity, and ore-bearing veins extend continuously throughout all sampled drillholes. Accordingly, fractal gradients can be utilized to depict prospective zones for favorable mineralization in uncharted regions. This methodology may be applicable to other structurally controlled mineral deposits where similar fracture-controlled mineralization occurs, though further testing on different deposit types is needed. Full article

(This article belongs to the Section Mineral Exploration Methods and Applications)

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Minerals, Volume 16, Issue 8 (August 2026) – 96 articles

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