Minerals

19 pages, 7276 KB

Open AccessArticle

Quantitative Evaluation of Sinter Reducibility Under Simulated Blast Furnace Conditions Using Microstructure Estimated by Hyperspectral Imaging

by Ryota Higashi, Daisuke Maruoka, Eiki Kasai, Kenya Horita and Taichi Murakami

Minerals 2026, 16(6), 653; https://doi.org/10.3390/min16060653 (registering DOI) - 20 Jun 2026

Abstract

Precise control of sinter reducibility is essential for stable blast furnace operation. Each mineral phase present in sinter, such as hematite, magnetite and calcium ferrite exhibits different reducibility. In XRD analysis, the requirement for sample pulverization leads to the loss of mineralogical texture [...] Read more.

Precise control of sinter reducibility is essential for stable blast furnace operation. Each mineral phase present in sinter, such as hematite, magnetite and calcium ferrite exhibits different reducibility. In XRD analysis, the requirement for sample pulverization leads to the loss of mineralogical texture information. This makes it difficult to quantitatively correlate the complex mineral phases present in the sinter with reducibility. This study introduces a novel quantitative approach using hyperspectral imaging to distinguish specific mineral morphologies. Reduction experiments simulating blast furnace thermal and gas conditions were conducted on several sinters. Multiple regression analysis was applied to correlate mineral fractions and macroporosity with reduction rates across three distinct reduction stages. In the low-temperature stage, hematite, macroporosity and acicular calcium ferrites were identified as the primary drivers of reduction. In the intermediate stage, acicular calcium ferrites continued to enhance reactivity, whereas coarse calcium ferrite showed a significant negative influence. In the high-temperature stage, macroporosity strongly promoted reduction, while coarse calcium ferrite and magnetite hindered it due to the formation of shell-like metallic iron structures which impede gas diffusion. These findings demonstrate that hyperspectral imaging combined with multi-stage regression analysis offers a useful tool for designing optimal sinter mineralogy for blast furnace performance. Full article

(This article belongs to the Special Issue Mineralogy of Iron Ore Sinters, 3rd Edition)

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27 pages, 5272 KB

Open AccessArticle

Porous Geopolymers Derived from Tunisian Clay and Mineral Wastes for Efficient Methylene Blue Removal

by Assia Ben Amor, Hadj-Otmane Chahinez, Abdelkader Ouakouak, Mohamed Mezni, Khaled Mahmoudi, Emad N. El Qada, Farid Fadhillah, Amine Aymen Assadi, Anouar Hajjaji, Noureddine Hamdi, Hichem Tahraoui and Abdeltif Amrane

Minerals 2026, 16(6), 652; https://doi.org/10.3390/min16060652 (registering DOI) - 20 Jun 2026

Abstract

The valorization of phosphogypsum (PG), a byproduct of phosphoric acid production, along with waste glass (WG) and silica fume (SF) into value-added materials has attracted growing attention in recent years. The present study aims to synthesize three types of porous geopolymers (GD, GDP, [...] Read more.

The valorization of phosphogypsum (PG), a byproduct of phosphoric acid production, along with waste glass (WG) and silica fume (SF) into value-added materials has attracted growing attention in recent years. The present study aims to synthesize three types of porous geopolymers (GD, GDP, and GDG) using Tunisian clay and locally available mineral wastes, and to investigate their potential as low-cost adsorbents for the removal of methylene blue (MB) dye from aqueous solutions. The physicochemical characteristics of the raw precursors and the resulting porous geopolymers were analyzed using various techniques, including FTIR, XRD, BET, and SEM. Variations in Si/Al, Na/Al, and Ca/Al ratios play a critical role in the geopolymer structure. The high Ca/Al ratio in GDP (porous geopolymer from calcined clay and phosphogypsum) promotes the formation of C-A-S-H, leading to increased macroporosity, which favors adsorption capacity despite the presence of a more heterogeneous morphology. The results indicated that the maximum adsorption capacity (Qmax) for MB dye was obtained for the GDP sample, reaching 68 mg/g. Adsorption experiments revealed the successful removal of MB dye by geopolymers, with the Langmuir isotherm and pseudo-second-order kinetic models adequately describing the adsorption process. The MB uptake by geopolymers was facilitated by weak physicochemical interactions, including electrostatic attraction, hydrogen bonding, and π–π interactions. This study proposes a simple and effective alkali activation strategy that combines different industrial wastes within a single geopolymer system, resulting in improved porosity and adsorption efficiency. Overall, the findings highlight the potential of these waste-derived geopolymers as promising and sustainable adsorbents for wastewater treatment applications. Full article

(This article belongs to the Section Clays and Engineered Mineral Materials)

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17 pages, 1181 KB

Open AccessArticle

Waste Stream Reduction by Combining Coarse Waste Preconcentration and Fine Tailings Utilization Technologies in a Copper Concentration Plant: The KGHM Polska Miedź S.A. Case Study

by Kajetan Witecki, Anna Jakubcewicz and Izabela Kruszwicka

Minerals 2026, 16(6), 651; https://doi.org/10.3390/min16060651 (registering DOI) - 19 Jun 2026

Abstract

The mining industry faces increasing challenges related to the growing volume of tailings generated during mineral processing. This study presents a case study of the Complex Mine Waste Reduction (CMWR) concept implemented at the Polkowice Concentrator operated by KGHM Polska Miedź S.A. The [...] Read more.

The mining industry faces increasing challenges related to the growing volume of tailings generated during mineral processing. This study presents a case study of the Complex Mine Waste Reduction (CMWR) concept implemented at the Polkowice Concentrator operated by KGHM Polska Miedź S.A. The approach integrates coarse ore sorting with tailings reprocessing for construction material production. Sorting improves flotation feed quality by rejecting low-grade gangue, while reprocessing converts fine tailings into value-added products. The combined implementation reduces tailing deposition by up to 22% and improves the operational copper recovery in flotation while maintaining overall process recovery at an essentially unchanged level. The results demonstrate the potential of integrated solutions for sustainable and circular mining. Full article

(This article belongs to the Special Issue Sustainable Extraction and Reuse of Metallurgical Wastes: Towards Circular Practices)

29 pages, 4624 KB

Open AccessArticle

Provenance and Sedimentary Environments of the Lower Cretaceous Huanhe Formation in the Northern Ordos Basin and Its Implications for Uranium Enrichment and Mineralization

by Zongyan Li, Tao Wang, Nan Peng, Jianliang Jia, Suping Li and Qingji Yao

Minerals 2026, 16(6), 650; https://doi.org/10.3390/min16060650 (registering DOI) - 19 Jun 2026

Abstract

Sandstone-type uranium deposits are the main source of uranium in China. The Ordos Basin, one of the most typical Mesozoic intracontinental sedimentary basins in northern China, is a major uranium-bearing basin in China. The Hangjinqi area is a significant uranium-bearing region in the [...] Read more.

Sandstone-type uranium deposits are the main source of uranium in China. The Ordos Basin, one of the most typical Mesozoic intracontinental sedimentary basins in northern China, is a major uranium-bearing basin in China. The Hangjinqi area is a significant uranium-bearing region in the northern Ordos Basin, with favorable geological conditions and promising exploration prospects for mineralization, and the Lower Cretaceous Huanhe Formation is one of the uranium-bearing strata in this area. This study focuses on the Huanhe Formation in the Hangjinqi area to investigate the governing factors of uranium enrichment and mineralization in this stratum. U-Pb dating of detrital zircons from sandstones of the Huanhe Formation reveals dominant peak ages of 2370–2585 Ma, 214–320 Ma, and 1805–2325 Ma, and secondary peak ages of 340–506 Ma, 1598–1797 Ma, and 110–150 Ma. The age results of the selected detrital zircons indicate that the provenance of the Huanhe Formation is mainly derived from three sources: (1) the 2.6–2.5 Ga TTG gneisses and granulites in the Yinshan Block; (2) the Paleoproterozoic (2500–1800 Ma) khondalites and granitic gneisses in the Daqingshan–Wulashan–Jining area, as well as granites in the Yinshan area; and (3) large-scale intermediate–acidic intrusive rocks and volcanic rocks of the Yinshan orogenic belt, whose ages range from 110.9 to 505.9 Ma (predominantly Paleozoic). These source rocks may have provided a potential uranium source. The paleoclimate proxies, including Sr/Cu, Sr/Ba, V/Cr, Ni/Co, and Fe²⁺/Fe³⁺ ratios, combined with the Chemical Index of Alteration (CIA) and the Index of Compositional Variability (ICV), suggest that the Huanhe Formation was formed in a relatively arid and oxidized environment with a low degree of chemical weathering, which facilitated the migration of uranium-bearing ore-forming fluids. The sedimentary environment, provenance, and paleoclimate created favorable geological conditions for uranium enrichment in the Huanhe Formation of the northern Ordos Basin. Full article

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

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25 pages, 58208 KB

Open AccessArticle

Soil Geochemistry and Exploration Implications of the Terziali Gold Prospect (Central Anatolia, Türkiye): A Case Study of Shear-Related Orogenic Gold Mineralization

by Özgür Sapancı, Nezihi Köprübaşı, Necla Köprübaşı, Olgun Duru, Yunus Emre Ekim and Emin Çiftci

Minerals 2026, 16(6), 649; https://doi.org/10.3390/min16060649 (registering DOI) - 19 Jun 2026

Abstract

The Terziali is a shear-hosted orogenic gold prospect located in the Central Anatolian Crystalline Complex, Türkiye. This study focuses on soil geochemistry, element correlations, background and threshold values, and evaluates exploration implications over a survey area of 35.5 km². A total [...] Read more.

The Terziali is a shear-hosted orogenic gold prospect located in the Central Anatolian Crystalline Complex, Türkiye. This study focuses on soil geochemistry, element correlations, background and threshold values, and evaluates exploration implications over a survey area of 35.5 km². A total of 1826 soil samples were collected from the B horizon using a grid of 100 × 50 m and were analyzed using ICP-AES, ICP-MS, and fire assay techniques. Statistical techniques of median + 2MAD threshold calculations, descriptive statistics, Kolmogorov–Smirnov tests, correlation analysis, hierarchical clustering, and Q–Q plots were carried out to identify geochemical anomalies. The data demonstrate Au threshold (28 ppb) and peak concentration (460 ppb), non-normal distributions characterized by strong positive skewness, revealing the outliers linked to mineralization. Soil geochemistry indicates a moderate association between Au and As in the four-acid dataset (r = 0.465), although the correlations between Au and Sb and Ag and W are relatively weak. The spatial analysis indicates that Au anomalies are predominantly linked to the NW–SE-oriented Demirli Thrust Fault. As displays extensive dispersion halos surrounding the gold anomalies; it establishes itself as an efficient pathfinder element. Conversely, Sb and W exhibit unique anomaly patterns, whereas Ag patterns are weak and dispersed. The Terziali prospect provides a substantial geochemical framework for identifying structurally controlled orogenic gold systems in Central Anatolia and the western Tethyan metallogenic belt. Full article

(This article belongs to the Special Issue Geochronology, Mineralogy, and Genesis of Orogenic Gold Deposit: Implications for Gold Prospecting)

25 pages, 12735 KB

Open AccessArticle

Fulvic Acid Influence on Arsenic Immobilization During Jarosite Bioreduction and Transformation

by Yi Shan, Wei-Xi Huang, Hong-Chang Liu, Zhen-Yuan Nie and Jin-Lan Xia

Minerals 2026, 16(6), 648; https://doi.org/10.3390/min16060648 (registering DOI) - 19 Jun 2026

Abstract

Acid mine drainage (AMD) is enriched with arsenite (As(III)), arsenate (As(V)), and jarosite. While jarosite can immobilize arsenic (As) through adsorption and other mechanisms, it dissolves and transforms into other minerals under near-neutral and reducing conditions via microbial mediation, thereby altering As fate. [...] Read more.

Acid mine drainage (AMD) is enriched with arsenite (As(III)), arsenate (As(V)), and jarosite. While jarosite can immobilize arsenic (As) through adsorption and other mechanisms, it dissolves and transforms into other minerals under near-neutral and reducing conditions via microbial mediation, thereby altering As fate. Fulvic acid (FA), a ubiquitous natural organic matter in the environment, has been proven to exhibit complex interactions with various iron minerals, Fe/S-metabolizing microorganisms, and As. However, the role of FA in the bioreduction and transformation of jarosite, as well as its subsequent impact on As mobility and fate, remains unclear. This study aims to elucidate the regulatory effect of FA on the biodissolution and transformation of jarosite, and the corresponding changes in As speciation. The results showed that FA exerted contrasting effects depending on arsenic speciation. In the As(III) treatments, FA intensified the inhibition of microbial dissimilatory sulfate reduction, suppressed sulfide production, and consequently limited orpiment formation. In contrast, in the As(V) treatments, FA enhanced the association of As(V) with jarosite surfaces, reduced aqueous As stress, and supported the persistence of As-tolerant sulfate-reducing populations. This promoted jarosite transformation toward mackinawite and facilitated As immobilization through orpiment precipitation. This study reveals the critical role of FA in the migration and transformation of As in mining areas, providing novel insights for optimizing AMD remediation strategies such as soil capping. Full article

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

22 pages, 5222 KB

Open AccessArticle

Selective Cobalt Extraction from Low-Grade Cobalt-Bearing Pyrite via Oxygen Pressure Acid Leaching

by Qiang Deng, Qingsheng Liu, Ziyang Zhou, Shigao Chen, Zihao Chen, Hao Wang, Guangyu Jiao and Ruzhen Peng

Minerals 2026, 16(6), 647; https://doi.org/10.3390/min16060647 (registering DOI) - 19 Jun 2026

Abstract

Cobalt occupies an irreplaceable strategic position in renewable energy and high-end advanced industries. As high-grade mineral resources gradually deplete, associated sulfide minerals have attracted increasing attention as alternative sources of cobalt. This study investigated a selective extraction of cobalt from low-grade cobalt-bearing pyrite [...] Read more.

Cobalt occupies an irreplaceable strategic position in renewable energy and high-end advanced industries. As high-grade mineral resources gradually deplete, associated sulfide minerals have attracted increasing attention as alternative sources of cobalt. This study investigated a selective extraction of cobalt from low-grade cobalt-bearing pyrite using oxygen-pressure acid leaching. The Gibbs free energy (ΔG) of key chemical reactions in the leaching system was calculated to verify the thermodynamic feasibility of the process. The effects of critical parameters, including oxygen pressure, initial acidity, stirring speed, leaching time, and temperature, on cobalt leaching efficiency and phase transformation characteristics were systematically investigated. Under optimal conditions of oxygen pressure 1.5 MPa, H₂SO₄ initial acidity 7.36 g·L⁻¹ (0.82 mol/L), stirring speed 300 rpm, leaching duration 120 min, and temperature 230 °C, the cobalt leaching rate reached 98.2%, whereas the leaching rates of iron and aluminum were only 19.79% and 28.11%, respectively. Combined with SEM-EDS, XRD, and XPS characterization results, oxygen pressure acid leaching effectively destroyed the lattice structure of cobalt-bearing pyrite and liberates lattice-hosted cobalt, thereby facilitating efficient cobalt leaching. At high-temperature and oxygen pressure conditions, Fe³⁺ underwent hydrolysis and precipitated as hematite (Fe₂O₃) or hydronium jarosite (H₃O)Fe₃(SO₄)₂(OH)₆, enabling the selective extraction of cobalt. Aluminum in cobalt-bearing pyrite primarily occurred as the stable boehmite (AlOOH) phase, exhibiting excellent acid resistance and low dissolution during leaching. This study broadens the utilization pathway of low-grade cobalt resources and provides valuable insights and a scientific theoretical basis for the efficient treatment of cobalt-containing sulfide concentrates and tailings. Full article

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

30 pages, 14880 KB

Open AccessArticle

Mineralogy, Geochemistry, and Uranium Enrichment of the NYF-Type Rare-Metal Pegmatites

by Gehad M. Saleh, Basma A. El-Badry, Amira M. EL Tohamy, Mohamed S. Kamar, Tamader Alhazanil, Mabrouk Sami, Ioan V. Sanislav and El Saeed R. Lasheen

Minerals 2026, 16(6), 646; https://doi.org/10.3390/min16060646 (registering DOI) - 18 Jun 2026

Abstract

The Gebel Shalman-Wadi Biarn (GSh-WB) area in Egypt’s South Eastern Desert hosts NYF-type rare-metal pegmatites with significant U, Th, Nb-Ta, and REEs mineralization. This study integrates field observations, petrography, mineralogy, whole-rock geochemistry, and gamma-ray spectrometry to characterize these pegmatites and evaluate their economic [...] Read more.

The Gebel Shalman-Wadi Biarn (GSh-WB) area in Egypt’s South Eastern Desert hosts NYF-type rare-metal pegmatites with significant U, Th, Nb-Ta, and REEs mineralization. This study integrates field observations, petrography, mineralogy, whole-rock geochemistry, and gamma-ray spectrometry to characterize these pegmatites and evaluate their economic potential. The pegmatites occur as veins, dykes, and zoned pockets hosted entirely within syenogranites. Petrography, pegmatites, and syenogranites are primarily composed of K-feldspar, albite, and quartz with trace amounts of biotite and muscovite. The environmental scanning electron microscope (ESEM) revealed the presence of the following minerals: autunite, kasolite, thorite, monazite-(Ce), parisite, xenotime-(Y), ferrocolumbite, hydroxyplumbobrtafite, aeschynite-(Y), and zircon, which are the major U-Th, Nb-Ta, and REE-bearing minerals. Additionally, gold, cassiterite, wolframite, pyrrhotite, chalcopyrite, and brass alloy were identified as sources of precious and base metals. Both groups’ chondrite-normalized REE patterns, which display slightly elevated LREE patterns and negative Eu anomalies, point to fractional crystallization involving plagioclase fractionation. Consequently, pegmatite and syenogranites are believed to have mostly formed from the partial melting of a reconstituted juvenile crust and its weathered sediments associated with Neoproterozoic magmatism. The marginally positive Ce anomaly in the (GSh-WB) pegmatites (1.02–0.98) may be associated with monazite crystallization resulting from enhanced fractionation. The Th and U levels range from 101 to 28.6 ppm and from 51 to 5.8 ppm, respectively. The magnitude of the tetrad effect in the rare earth elements of the analyzed rocks exceeds one (T1 = 1.12–1.02, T3 = 0.92–1.08, and T1,3 = 1.01–1.05), suggesting an M-type tetrad effect. The presence of this tetrad effect is indicative of granite that has been significantly altered by hydrothermal processes and is extensively fractionated. Chondrite-normalized REE patterns of the pegmatites (average ΣREE = 439 ppm) and their host syenogranites (average ΣREE = 192 ppm) show similar trends characterized by enrichment of light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs) and pronounced negative Eu anomalies (Eu/Eu* = 0.09–0.22). These features, together with negative Sr and Ba anomalies, likely reflect extensive fractional crystallization of feldspars and feature anorogenic rocks. Spectrometric analysis reveals eU values of 2.0–288 ppm and eTh values of 7.0–455 ppm in pegmatite samples, with eU/eTh ratios (0.49–0.39) exceeding the typical continental crust value of 0.25, indicating uranium enrichment. Both magmatic and hydrothermal processes contributed to the observed radioactivity. The spatial distribution of uranium shows lithological and structural controls. The GSh-WB pegmatites represent a potential target for uranium exploration. Full article

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

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28 pages, 1832 KB

Open AccessArticle

Analysis of the Chemical and Radiological Risks Associated with Wastes from Mining in the Iberian Pyrite Belt

by Juan Antonio Ramírez-Pérez, Manuel Jesús Gázquez-González, Felipe Jesús González-Barrionuevo and Juan Pedro Bolívar

Minerals 2026, 16(6), 645; https://doi.org/10.3390/min16060645 (registering DOI) - 18 Jun 2026

Abstract

Mining activities in the Iberian Pyrite Belt have generated large volumes of legacy wastes that may pose both environmental and radiological concerns, potentially limiting their reuse and valorization. However, integrated assessments combining chemical, mineralogical, and radiological characterization of these materials remain scarce. In [...] Read more.

Mining activities in the Iberian Pyrite Belt have generated large volumes of legacy wastes that may pose both environmental and radiological concerns, potentially limiting their reuse and valorization. However, integrated assessments combining chemical, mineralogical, and radiological characterization of these materials remain scarce. In this work, representative mining wastes from twelve sites across the Iberian Pyrite Belt were investigated through X-ray fluorescence, X-ray diffraction, scanning electron microscopy, standardized leaching tests, alpha and gamma spectrometry, and radon emanation measurements. The results revealed significant enrichment in potentially toxic elements, particularly Cu, Zn, Pb, and As, with concentrations exceeding local soil background values by up to several orders of magnitude. Leaching tests identified oxidized sulfide-rich residues as the materials with the highest pollutant mobility and greatest acid-generating potential. In contrast, radiological characterization showed that uranium-series, thorium-series radionuclides, and ⁴⁰K activities, together with radiological hazard indices and radon exhalation rates, were generally comparable to those of surrounding natural soils and remained below internationally recommended limits. These findings indicate that chemical contamination represents the main environmental constraint of these wastes, whereas radiological impact is generally low, supporting their case-by-case evaluation for remediation, valorization, and potential exclusion from radiological control. Full article

(This article belongs to the Special Issue Radionuclides and Radiation Exposure in Minerals Extraction, Processing and Applications)

21 pages, 2588 KB

Open AccessArticle

Petrogenesis and Geological Significance of the Jasacuo Monzogranite, Western Gangdese Belt, Southern Tibet: SIMS Zircon U-Pb Chronological and Whole-Rock Geochemical Constraints

by Wenwen Han, Qin Qin, Zhipen Liu, Yu Wu, Yunhe Liu and Wei Xu

Minerals 2026, 16(6), 644; https://doi.org/10.3390/min16060644 (registering DOI) - 18 Jun 2026

Abstract

Early Cretaceous magmatism in the western segment of the Gangdese belt is less well constrained than that in the central and eastern segments. This study presents petrography, whole-rock geochemistry, and SIMS zircon U–Pb geochronology for the Jasacuo monzogranite in Zhongba County, southern Tibet. [...] Read more.

Early Cretaceous magmatism in the western segment of the Gangdese belt is less well constrained than that in the central and eastern segments. This study presents petrography, whole-rock geochemistry, and SIMS zircon U–Pb geochronology for the Jasacuo monzogranite in Zhongba County, southern Tibet. Zircons are euhedral and show oscillatory zoning; 17 concordant analyses yield a weighted mean ²⁰⁶Pb/²³⁸U age of 101.4 ± 0.8 Ma (MSWD = 1.01), indicating crystallization in the late Early Cretaceous. The rocks are characterized by high SiO₂ (63.73–77.11 wt.%), high K₂O, low MgO, TiO₂, and P₂O₅, and A/CNK values of 0.92–1.08, indicating metaluminous to weakly peraluminous, high-K calc-alkaline compositions with I-type affinity. Chondrite-normalized REE patterns show LREE enrichment and negative Eu anomalies, whereas primitive-mantle-normalized trace-element patterns display enrichment in Rb, U, Th, and Pb and depletion in Ba, Nb, Sr, Zr, and Ti. These features indicate that the Jasacuo monzogranite is an evolved felsic intrusion generated in a subduction-related continental-arc setting associated with northward subduction of the Neo-Tethyan oceanic lithosphere. The magma was dominated by crustal components and underwent significant fractional crystallization, mainly involving feldspar, with minor biotite and amphibole. 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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15 pages, 3355 KB

Open AccessArticle

Assessment of Cu, As, Pb, Zn and Fe Enrichment in Intertidal Sediments Along the Atacama Coast, Northern Chile

by Estefanía Bonnail, Edgardo Cruces, John Santibáñez, Juan Manuel Muñoz, María Isabel Prudencio, María Isabel Dias, Rosa Marques, Manuel Abad, Tatiana Izquierdo and Francisco Ruiz

Minerals 2026, 16(6), 643; https://doi.org/10.3390/min16060643 (registering DOI) - 18 Jun 2026

Abstract

Textural and geochemical analysis of intertidal sediments in the southern Atacama region makes it possible to identify sites primarily affected by mining-related pollution, based on a multivariate statistical analysis of the concentrations of five elements (Fe, Cu, Zn, As, Pb) and their geoaccumulation [...] Read more.

Textural and geochemical analysis of intertidal sediments in the southern Atacama region makes it possible to identify sites primarily affected by mining-related pollution, based on a multivariate statistical analysis of the concentrations of five elements (Fe, Cu, Zn, As, Pb) and their geoaccumulation indices. These concentrations are not correlated with grain size, which is dominated by the sandy fractions. Spearman’s matrix and principal component analysis make it possible to distinguish between two groups of elements (group A: Fe-Cu-As; group B: Zn-Pb), with a strong correlation between them (ρ ≥ 0.51; p < 0.01) and the first two components explain 96.3% of the variance. Three heavily polluted sites (Playa Blanca, Bahía Sarco and Chañaral de Aceituno; I_geo Cu > 8) have been identified linked to waste from the washing of tailings, a copper smelter and frequent boat trips. In addition, four moderately polluted sites (Playa Grande, Balneario Caldera, the mouth of the Copiapó River and Carrizal Bajo; 1.7 < I_geo Cu < 8; 1.2 < I_geo Pb < 2.6), mainly due to activities associated with mining and oil refineries, have been identified. Full article

(This article belongs to the Topic Environmental Pollution and Remediation in Mining Areas)

24 pages, 11221 KB

Open AccessArticle

Carboniferous Slab Rollback in the Eastern Tianshan, NW China: Insights from Basalts of the Qi’Eshan Group in the Dananhu Arc

by Jixiang Dai, He Yang, Hongming Cai, Yuyu Zong and Feng Gao

Minerals 2026, 16(6), 642; https://doi.org/10.3390/min16060642 (registering DOI) - 18 Jun 2026

Abstract

Volcanic rocks of the Qi’eshan Group, which are widely distributed in the Dananhu arc of the Eastern Tianshan, NW China, have long been debated in terms of their formation age and tectonic setting. In this study, we conducted an integrated study of U-Pb [...] Read more.

Volcanic rocks of the Qi’eshan Group, which are widely distributed in the Dananhu arc of the Eastern Tianshan, NW China, have long been debated in terms of their formation age and tectonic setting. In this study, we conducted an integrated study of U-Pb apatite geochronology, whole-rock major and trace element geochemistry, in situ major element analyses of clinopyroxene, and “Rhyolite-MELTS” thermodynamic modeling on the basalts from the Qi’eshan Group. Geochronological data show that the weighted mean of ²⁰⁶Pb/²³⁸U ages of apatite is 329 ± 10 Ma. The basalts belong to the tholeiitic series and are characterized by enrichment in large ion lithophile elements (LILEs), depletion in high field strength elements (HFSEs), and enrichment of light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs) with weak negative Eu anomalies. They were derived by partial melting of garnet-spinel lherzolite in a depleted mantle source metasomatized by subduction-related fluids, followed by fractional crystallization of spinel, olivine, and clinopyroxene. Clinopyroxene is dominated by augite, characterized by high Mg and Ca contents and low Al and Na contents. Machine-learning-based thermobarometry indicates that clinopyroxene crystallized at temperatures of 1027–1033 °C and pressures of 1.1–1.6 kbar. “Rhyolite-MELTS” isobaric crystallization simulations suggest that mantle-derived magma, with an initial water content of 4 wt.% and oxygen fugacity of FMQ, can generate melts compositionally similar to the volcanic rocks of the Qi’eshan Group through fractional crystallization at a pressure of 1.5 kbar. Combined with previous studies, we propose that the Qi’eshan Group basalts formed in an extensional arc setting related to southward rollback of the northward-subducting Kanguer oceanic slab, which caused asthenosphere upwelling and lithospheric extension, thereby promoting partial melting of the subduction-metasomatized mantle. Our data provide new insights into the Carboniferous rollback of the Kanguer oceanic slab in the northern part of the Eastern Tianshan. Full article

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

28 pages, 4167 KB

Open AccessArticle

Sedimentary Evolution and Reservoir Formation of the Late Triassic Bolila Formation in the Central Qiangtang Basin, Tibet

by Shangke Xie, Haisheng Yi, Wangzhong Zhan, Ruiyu Cheng, Wei Sun, Shengqiang Zeng, Qian Hou and Keyu Zhu

Minerals 2026, 16(6), 641; https://doi.org/10.3390/min16060641 (registering DOI) - 18 Jun 2026

Abstract

The Late Triassic Bolila Formation in the central Qiangtang Basin is a typical carbonate buildup deposited during a regional transgression in the eastern Tethyan realm. Understanding its sedimentary evolution and reservoir-forming mechanisms is crucial for hydrocarbon exploration. This study integrates petrology, detrital zircon [...] Read more.

The Late Triassic Bolila Formation in the central Qiangtang Basin is a typical carbonate buildup deposited during a regional transgression in the eastern Tethyan realm. Understanding its sedimentary evolution and reservoir-forming mechanisms is crucial for hydrocarbon exploration. This study integrates petrology, detrital zircon U-Pb geochronology, carbon-oxygen isotopes, and reservoir property analysis of the Quemudongda section. The results show: (1) detrital zircon dating provides a maximum depositional age of 225.7–235.7 Ma (Carnian–Norian), correcting the previous Jurassic misassignment on the 1:250,000 geological map. Carbon-oxygen isotopes (average δ¹³C = +3.2‰, δ¹⁸O = −11.1‰) are consistent with the global Carnian–Norian positive δ¹³C excursion. (2) The section reveals a platform-margin reef (hexactinellid and calcareous sponges) and slump breccia (seven layers) association, representing a steep-rimmed carbonate platform margin. The sedimentary evolution comprises three stages: reef initiation, reef flourishing with frequent slumping, and reef decline with dolomitization. (3) Reservoirs are mainly breccia and reef dolostones, with intergranular, intercrystalline, and fracture-related pores. Porosity averages 2.8% (0.8%–7.2%), permeability averages 0.35 mD (0.001–8.5 mD), defining a low-porosity, ultra-low-permeability fracture-pore reservoir. Breccia dolostone has better properties (porosity 3.71%, permeability 2.412 mD). (4) Reservoir formation is controlled by sedimentation (platform-margin facies), diagenesis (dolomitization generates pores, but high-temperature recrystallization causes densification), and tectonics (microfractures enhance permeability). High-quality reservoirs occur where breccia dolostone and fractures overlap. (5) The Bolila reef-shoal complex and the overlying Bagong Formation source rocks form a “lower reservoir—upper source” assemblage, representing a new exploration target in the Tuonamu area. The breccia dolostone–fracture overlap zone is the core “sweet spot”. Full article

(This article belongs to the Special Issue Island-Reef Carbonate Systems: Facies, Diagenesis, and Dolomitization Processes)

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21 pages, 26913 KB

Open AccessArticle

Pre-Concentration of Low-Grade Hard-Rock Uranium Ore by Dense Medium Cyclone Separation: Mineralogical Constraints and CFD Validation

by Guang Li, Xue-Bin Su, Ai-Fei Yi, Jia Ma and Xian-Ming Hou

Minerals 2026, 16(6), 640; https://doi.org/10.3390/min16060640 - 17 Jun 2026

Abstract

The mineralogical characteristics of low-grade hard-rock uranium ore from the Zoujiashan deposit were systematically investigated via multiple analytical techniques, including chemical analysis, X-ray fluorescence (XRF) spectrometry, uranium occurrence analysis, 3D X-ray micro-computed tomography (CT), an automated mineral identification and characterization system (AMICS), and [...] Read more.

The mineralogical characteristics of low-grade hard-rock uranium ore from the Zoujiashan deposit were systematically investigated via multiple analytical techniques, including chemical analysis, X-ray fluorescence (XRF) spectrometry, uranium occurrence analysis, 3D X-ray micro-computed tomography (CT), an automated mineral identification and characterization system (AMICS), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The results revealed that the uranium grade of the ore was only 0.202%, among which 65.87% existed in the form of independent uranium minerals, while the remaining 34.13% existed in a dispersed ionic state. Except for quartz, most uranium minerals and gangue minerals were finely disseminated and closely intergrown. The pre-concentration of the ore is therefore necessary to separate uranium-rich particles from barren particles at a coarse particle size. Ore density analysis demonstrated that the feed particle size exerted a significant impact on the separation performance, and the optimum feed particle size was determined to be 20 mm. Subsequently, dense medium cyclone (DMC) separation tests were conducted. The experimental results indicated that fine grains were prone to report to low-density products (tailings) during mixed-size beneficiation. Under a tailings yield of 54%, for the −20 + 8 mm coarse fraction, the tailings uranium grade was 0.025% and the uranium recovery of the concentrate was 88.05%. Therefore, classified separation can effectively promote separation efficiency. To reveal the density control mechanism of the particle separation behavior inside the DMC, computational fluid dynamics (CFD) simulations were implemented with the Eulerian–Eulerian multiphase model in ANSYS-Fluent (version 2020R2). The simulation results suggested that a density difference of 8.6% realized effective separation. This work achieved the effective treatment of low-grade hard-rock uranium ore via DMC separation, providing a novel technical route for uranium ore pre-concentration. Full article

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

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22 pages, 3275 KB

Open AccessArticle

The Deep Prediction of the Tonglushan Deposit Based on the Wide-Field Electromagnetic Method and Radiometric Spectrometry Measurements

by Yepeng Zhang, Jiabin Yan and Chaoyu Huang

Minerals 2026, 16(6), 639; https://doi.org/10.3390/min16060639 - 16 Jun 2026

Abstract

The Tonglushan ore field is an important component of the polymetallic mineralization belt in the middle and lower reaches of the Yangtze River in China. The skarn-type Cu, Fe, Au, and Mo molybdenum deposits are mainly developed in the contact zone between the [...] Read more.

The Tonglushan ore field is an important component of the polymetallic mineralization belt in the middle and lower reaches of the Yangtze River in China. The skarn-type Cu, Fe, Au, and Mo molybdenum deposits are mainly developed in the contact zone between the rock mass and the strata, as well as in the contact zone between residual and capturing bodies in the rock body. The distribution of ore bodies is controlled by faults and strata, but there is a lack of large-scale geophysical information on the contact relationship between the ore-forming geological body and the host rock and on the deep spatial morphology of the ore-forming structure and intrusion rock. The study uses the JS-WEM2 wide-field electromagnetic instrument and the RS230 spectrometer to conduct the ground frequency domain electromagnetic and radiometric spectrometry measurements on four profiles. The measurement results indicate that the fault distribution in the Tonglushan ore field is predominantly in the NW-trending and NE-trending directions. The NW-trending Tonglushan–Lijiashan fault (F2) is a steeply dipping fault; the NE-trending faults are minor, with steep dips, generally extending no deeper than −1000 m. The Tonglushan stock exhibits the northeastward uplift, characterized by southward overlap and southeastward dip. The deep resistivity is greater than 3000 Ω·m, while the resistivity below −1000 m is less than 2000 Ω·m due to the fault influence. The ore bodies are mainly distributed along the contact zones where variations in the occurrence of the rock intersect with the strata. On resistivity profiles, these zones show the gradient variation in resistivity and the distorted shape of the resistivity contour line. The radioactive element contents of wall rock above the ore bodies are characterized by high U, high Th, and low K. The Wide-Field Electromagnetic Method (WFEM) can effectively detect the distribution and morphology of rocks and faults, and combined with the radioactive characteristics of geological bodies, it can effectively identify concealed faults and the favorable mineralization target areas. Novelty: The study combines the WFEM with radiometric measurements to reduce uncertainty in exploration compared to using only one method. It improves the detection accuracy and target identification ability of deep hidden ore bodies, providing the new technical method for deep mineral exploration in complex structural areas. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery, 2nd Edition)

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27 pages, 40534 KB

Open AccessArticle

Extraction of Regional and Local Anomalies of Element Group in the Ailaoshan Tectonic Zone, Southwestern China

by Xiaoli Qi, Aoyue Zheng, Yongqing Chen and Pengda Zhao

Minerals 2026, 16(6), 638; https://doi.org/10.3390/min16060638 - 16 Jun 2026

Abstract

Geochemical data provide direct constraints on mineralization, and the extraction of mineralization-related geochemical anomalies is essential for mineral resource prediction and assessment. The regional geochemical field reflects the spatial expression of ore-forming environments resulting from the superposition of multiple geological processes, with distinct [...] Read more.

Geochemical data provide direct constraints on mineralization, and the extraction of mineralization-related geochemical anomalies is essential for mineral resource prediction and assessment. The regional geochemical field reflects the spatial expression of ore-forming environments resulting from the superposition of multiple geological processes, with distinct elemental assemblages corresponding to different processes. The Ailaoshan metallogenic belt, located in the southeastern segment of the India–Eurasia collisional orogen, experienced multiple episodes of opening and closure, extension, amalgamation, and compression, leading to intense deformation. Its complex structural framework, multistage magmatism, and metamorphism have generated abundant mineral resources, particularly Au, Sn, Cu, Pb-Zn, and Ni deposits. Using the 1:200,000–scale national stream sediment geochemical dataset, principal component analysis (PCA) was applied to identify major ore-forming elemental assemblages. Singular value decomposition (SVD) was then used to extract regional and local anomalies for PC2 (Ag-As-Bi-Cu-Mn-Pb-Sn), PC3 (B-Be-Bi-Cu-F-W), PC4 (La-Nb-Th-U-Y-Zr), and PC10 (Au-Hg). Ultimately, six metallogenic prospective areas were consequently delineated. Full article

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

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27 pages, 14942 KB

Open AccessArticle

An Explainable Deep Learning Framework for Morphology-Aware Coal Surface Characterization and Intelligent Coal Processing

by Mustafa Coşar

Minerals 2026, 16(6), 637; https://doi.org/10.3390/min16060637 - 16 Jun 2026

Abstract

Coal surface morphology plays a pivotal role in advanced coal processing operations, encompassing comminution, beneficiation, flotation kinetics, and intelligent process optimization. However, conventional characterization approaches are inherently labor-intensive and susceptible to inter-operator subjectivity, hindering their integration into autonomous industrial monitoring systems. To surmount [...] Read more.

Coal surface morphology plays a pivotal role in advanced coal processing operations, encompassing comminution, beneficiation, flotation kinetics, and intelligent process optimization. However, conventional characterization approaches are inherently labor-intensive and susceptible to inter-operator subjectivity, hindering their integration into autonomous industrial monitoring systems. To surmount these challenges, this study proposes an explainable morphology-aware coal surface characterization framework that synergizes unsupervised pseudo-label generation, targeted data augmentation, and explainable artificial intelligence. Initially, a high-dimensional feature set comprising grayscale intensity statistics, entropy, edge density, and Gray-Level Co-occurrence Matrix descriptors was extracted from 454 coal surface images. Subsequently, Principal Component Analysis and K-means clustering were implemented to identify intrinsic morphology-driven structural patterns, generating robust pseudo-labels without manual annotation. These pseudo-classes were utilized to train and benchmark multiple transfer learning architectures, including EfficientNetB0, VGG16, and MobileNetV3. Experimental results demonstrated that MobileNetV3 achieved superior classification efficacy under a strict leakage-safe evaluation configuration, exceeding 90% across key performance metrics while offering significantly lower computational complexity—ideal for edge-computing deployment. Furthermore, Grad-CAM-based interpretability analysis validated that the models focused on physically significant morphological features, such as fracture boundaries and heterogeneous texture transitions. These findings indicate that the proposed framework provides a robust, computationally efficient, and interpretable decision-support tool for smart beneficiation and intelligent industrial coal processing environments. Full article

(This article belongs to the Special Issue Advanced Coal Processing: Comminution, Concentration, Desulphurization and Process Optimization)

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13 pages, 5820 KB

Open AccessArticle

Mineralogical and Geochemical Characterization of Deep Tight Gas in Shahezi Formation, Songliao Basin, NE China

by Jizu Wen, Shangfeng Zhang, Qi Chen, Guanghui Huang, Nishan Wang and Zhenxiang Chen

Minerals 2026, 16(6), 636; https://doi.org/10.3390/min16060636 - 15 Jun 2026

Abstract

Tight gas is a critical unconventional energy resource, yet the geological characteristics and accumulation processes of tight gas in China’s Songliao Basin remain poorly documented. This study aims to investigate the tight gas system in the Songliao Basin as a representative continental basin, [...] Read more.

Tight gas is a critical unconventional energy resource, yet the geological characteristics and accumulation processes of tight gas in China’s Songliao Basin remain poorly documented. This study aims to investigate the tight gas system in the Songliao Basin as a representative continental basin, with key objectives including evaluating source rock and reservoir properties via mineralogical and geochemical analyses, characterizing lithologies and pore types, determining the gas charging mechanism in tight media, and identifying the main controlling factors for accumulation. Geochemical results indicate that the Shahezi Formation contains medium to good mudstones and excellent coals. Reservoirs consist of tight sandstones and conglomerates deposited in fan delta and braided river delta systems, with pore spaces dominated by dissolution pores and microfractures, resulting in ultra-low porosity and permeability. Conventional buoyancy-driven migration is ineffective; instead, gas charging is driven by hydrocarbon generation expansion force, creating overpressure that expels pore water and forces gas into reservoirs through fault-sand conduits. Accumulation is controlled by continuous gas supply from thick, highly mature source rocks, dissolution-enhanced and fracture-dominated reservoir space, and sufficient source–reservoir pressure difference. This study elucidates tight gas characteristics and accumulation mechanisms in continental basins, providing data applicable to both continental and marine settings. Full article

(This article belongs to the Special Issue Geochemical Controls on the Generation and Transformation of Carbon in Rocks)

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21 pages, 6816 KB

Open AccessArticle

Metallogenic Potential and Ore-Forming Fluid Evolution of the Dadonggou Molybdenum Deposit in Northwest Hebei, China: Geochemical and Isotopic Constraints

by Guanghuo Tao, Deyou Sun, Fenghao Li, Xingkang Zhang, Zhao Feng, Guang Wang and Xiaozhuo Jia

Minerals 2026, 16(6), 635; https://doi.org/10.3390/min16060635 - 15 Jun 2026

Abstract

The Dadonggou Mo deposit in Western Hebei, within the Yanshan–Liaoning Mo metallogenic belt, is a newly recognized medium-sized porphyry Mo system. Exploration has delineated 126 orebodies, most of which are blind, with identified resources of ~22,000 t Mo at an average grade of [...] Read more.

The Dadonggou Mo deposit in Western Hebei, within the Yanshan–Liaoning Mo metallogenic belt, is a newly recognized medium-sized porphyry Mo system. Exploration has delineated 126 orebodies, most of which are blind, with identified resources of ~22,000 t Mo at an average grade of 0.071% Mo. Integrated lithogeochemistry, zircon U-Pb chronology, molybdenite Re-Os geochronology, quartz fluid-inclusion microthermometry, and H-O-S isotope analyses constrain the mineralization age, ore-fluid evolution, and sources of ore-forming materials. The zircon U-Pb dating of the ore-bearing granite porphyry and quartz porphyry from the Dadonggou molybdenum deposit yields ages ranging from 135.8 Ma to 141.5 Ma. The low Ti content in zircons indicates that they are super-wet magmatic rocks. The magmatic evolution experienced a change in oxygen fugacity from oxidizing to reducing conditions, which facilitated the initial enrichment of molybdenum. Molybdenite yields a Re-Os isochron age of 135.9 ± 4.0 Ma and a weighted mean model age of 134.2 ± 1.6 Ma, indicating Early Cretaceous mineralization. Ore fluids evolved from an early CO₂-H₂O-NaCl system with relatively high temperature and salinity to a later H₂O-NaCl system with lower temperature and salinity. Isotopic data indicate progressive meteoric-water incorporation into dominantly magmatic fluids. Sulfur isotopes and high Re contents in molybdenite indicate a mixture of mantle magma mixed with some seawater. Lower late-stage trapping pressures record post-ore depressurization and hydrothermal-system shallowing. Full article

(This article belongs to the Section Mineral Deposits)

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