Minerals

20 pages, 6720 KB

Open AccessArticle

Gold and Silver Recovery from a Refractory Pyritic Concentrate by Roasting and Alkaline Pressure Oxidation

by Ana María Espinoza-Martínez, Jesús Leobardo Valenzuela-García, María Mercedes Salazar-Campoy, Martín Antonio Encinas-Romero, Guadalupe Martínez-Ballesteros and José Refugio Parga Torres

Minerals 2025, 15(12), 1260; https://doi.org/10.3390/min15121260 (registering DOI) - 28 Nov 2025

Abstract

Refractory gold and silver ores present significant challenges because precious metals are encapsulated within sulfide matrices, severely limiting extraction by conventional cyanidation. In this study, a pyritic concentrate from the Bacis Mine (Durango, Mexico) was characterized and subjected to two oxidative pretreatments—roasting and [...] Read more.

Refractory gold and silver ores present significant challenges because precious metals are encapsulated within sulfide matrices, severely limiting extraction by conventional cyanidation. In this study, a pyritic concentrate from the Bacis Mine (Durango, Mexico) was characterized and subjected to two oxidative pretreatments—roasting and alkaline pressure oxidation—before cyanidation. X-ray diffraction confirmed pyrite to be the dominant phase, with quartz and minor carbonates contributing to the material’s refractory character. Roasting at 550 °C achieved gold and silver extraction of 80% and 70%, respectively, which improved to 89% Au and 74% Ag with the addition of hydrogen peroxide. In contrast, alkaline pressure oxidation at 150 °C and 1 MPa O₂ yielded the highest extraction of 92% for Au and 76% for Ag at 1 h. Thermodynamic analysis using the Fe–S Pourbaix diagram at 80 °C supported these experimental results, showing the destabilization of FeS₂ under oxidizing and moderately alkaline conditions. Overall, this study demonstrates that alkaline pressure oxidation is a technically efficient and environmentally favorable pretreatment for refractory gold ores. Full article

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

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22 pages, 4926 KB

Open AccessArticle

Recycling Copper (Cu) from Waste Automotive Printed Circuit Boards (WPCBs) After Characterization and Liberation Study by Mineral Processing Techniques

by Mahsa Pourmohammad, Josep Oliva, Hernan Anticoi, Carlos Hoffmann Sampaio, Pura Alfonso, César Valderrama, Jose Luis Cortina and Percy Escalante

Minerals 2025, 15(12), 1259; https://doi.org/10.3390/min15121259 - 27 Nov 2025

Abstract

Waste printed circuit boards (WPCBs) are one of the fastest-growing waste streams and pose a significant environmental challenge while also representing a valuable secondary resource due to their rich metal content, particularly copper (Cu). Since effective recovery of metals requires mechanical pre-treatment and [...] Read more.

Waste printed circuit boards (WPCBs) are one of the fastest-growing waste streams and pose a significant environmental challenge while also representing a valuable secondary resource due to their rich metal content, particularly copper (Cu). Since effective recovery of metals requires mechanical pre-treatment and advanced characterization, WPCB boards were subjected to size reduction and then characterized through X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM-EDS), and mineral liberation analysis (MLA). Results indicated that copper is predominantly found in coarser particle sizes due to its ductility, while glass fibers and ceramics dominate finer fractions. Liberation studies revealed that Cu is essentially free in fine particles (<100 μm) but tends to remain locked in coarser fractions. Based on these results, gravity separation methods were employed to concentrate the copper: coarse particles (>300 μm) were treated on a shaking table, achieving a Cu recovery of 95%, while fine particles (<300 μm) were processed using a multi-gravity separator (MGS), with recoveries of 94% for 100 × 300 μm and 81.5% for <100 μm size fractions. This study presents a gravity-based separation strategy that combines shaking tables and MGS to optimize Cu recovery from automotive WPCBs. To the authors’ knowledge, the MGS application for WPCBs has received little attention, despite its strong potential for separating this type of waste. The proposed methodology enhances the concentration and purity of the metallic fraction (in this case, Cu), especially in fine particles, which are challenging to work with, while reducing environmental impacts through minimal chemical use, thereby contributing to sustainable e-waste recycling. Full article

(This article belongs to the Special Issue Waste Valorization: Recycling and Recovery of Critical and Strategic Metals)

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18 pages, 2177 KB

Open AccessArticle

Decarbonizing Red Ceramics Through Sustainable Formulations of Complementary Raw Materials

by Carla Candeias and Fernando Rocha

Minerals 2025, 15(12), 1258; https://doi.org/10.3390/min15121258 - 27 Nov 2025

Abstract

Red ceramics remain essential in construction worldwide, but face challenges associated with high energy demand and CO₂ emissions. Sustainable alternatives require valorization of local georesources and adoption of circular economic approaches. This study evaluated two ceramic pastes formulations designed from locally available [...] Read more.

Red ceramics remain essential in construction worldwide, but face challenges associated with high energy demand and CO₂ emissions. Sustainable alternatives require valorization of local georesources and adoption of circular economic approaches. This study evaluated two ceramic pastes formulations designed from locally available raw materials in southern Portugal: batch AD2, a 1:1 blend of residual clays from Corval, and batch XB1, a 1:1 blend of residual clay from Corval and a clay-schist from Barrancos. Raw materials were selected to balance contrasting properties, i.e., smectite-rich clays with high plasticity and shrinkage versus illitic (coarser) schists with lower plasticity and tempering effects. Batches were extruded, dried, fired at 1100 and 1150 °C, and tested for shaping moisture, shrinkage, water absorption, flexural strength, and mineralogical evolution. Results showed that the residual clays batch required high shaping moisture (20.04%) but achieved controlled drying shrinkage and high dry strength due to the smectite/temper balance. After firing, the material exhibited total shrinkage of 9.12 ± 0.28 and 9.78 ± 0.11%, water absorption of 11.57 ± 0.30 and 9.85 ± 0.27%, and flexural strength of 13.95 ± 2.30 and 14.85 ± 2.68 MPa, with mullite formation enhancing its performance. Clay and schist batch, after drying at 110 °C displayed low shaping moisture (6.22%), minimal drying shrinkage (0.15 ± 0.06%), and moderate fired (1100 and 1150 °C) shrinkage (1.59 ± 0.06 and 2.77 ± 0.04%). Water absorption decreased from 12.10 ± 0.77 to 9.91 ± 0.80% as the temperature increased, while flexural strength rose significantly from 13.60 ± 0.74 to 19.69 ± 1.54 MPa. Both blends developed desirable red tones without efflorescence. These findings demonstrated that residual clays and clay-schist can be effectively blended to produce sustainable, high-quality red ceramics, meeting structural requirements while promoting resource efficiency, reducing transport, and supporting decarbonization strategies. Full article

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

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21 pages, 4498 KB

Open AccessArticle

Semantic-Aware Fusion of Mineral Exploration Knowledge Streams Towards Dynamic Geological Knowledge Graphs

by Ying Qin, Hui Yang, Liu Cui, Yuan Zhang, Gefei Feng, Yina Qiao and Yuejing Yao

Minerals 2025, 15(12), 1257; https://doi.org/10.3390/min15121257 - 27 Nov 2025

Abstract

Integrating heterogeneous and multilingual geoscience texts into coherent knowledge graphs is challenged by semantic inconsistencies from terminology variations, diverse expressions, and data heterogeneity, hindering the construction of reliable mineral exploration knowledge systems. We propose a semantic-aware fusion framework that enables consistent and sustainable [...] Read more.

Integrating heterogeneous and multilingual geoscience texts into coherent knowledge graphs is challenged by semantic inconsistencies from terminology variations, diverse expressions, and data heterogeneity, hindering the construction of reliable mineral exploration knowledge systems. We propose a semantic-aware fusion framework that enables consistent and sustainable integration of mineral exploration knowledge. Built on a standardized geological knowledge schema defining core entities and their interrelations, the framework incorporates an incremental update paradigm via a schema-guided fusion mechanism that detects and resolves semantic conflicts while preserving provenance for traceable evolution. Evaluated on textual sources, the framework achieves an overall triple extraction F1-score of 0.82. Notably, for the critical task of entity extraction, it attains an F1-score of 0.88, outperforming BERT-BiLSTM and BERT-BiLSTM-CRF baselines by up to 11 points. Precision for key metallogenic elements exceeds 0.90. It identifies 1432 conflicts during fusion and generates a refined knowledge graph of 18,204 high-quality de-duplicated triples, retaining 87.3% of inputs. The resulting graph supports downstream applications, including case analysis, visualization, question answering, and mineral prospectivity prediction. Unlike conventional aggregation approaches, this work treats knowledge fusion as a semantically guided dynamic process, enhancing consistency, transparency, and adaptability. It provides a practical pathway toward intelligent and sustainable geoscience knowledge infrastructures. Full article

(This article belongs to the Special Issue Application of Big Data Mining, Machine Learning and Artificial Intelligence in Geoscience, 2nd Edition)

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18 pages, 2359 KB

Open AccessArticle

Preparation Process and Performance of Mineral Admixtures Derived from High-Sulfur Lead-Zinc Tailings

by Mengyuan Li, Mingshan Gong, Hangkong Li, Lijie Guo, Zhong Li, Xin Guo, Yanying Yin and Tingting Ren

Minerals 2025, 15(12), 1256; https://doi.org/10.3390/min15121256 - 27 Nov 2025

Abstract

The large-scale accumulation of high-sulfur lead–zinc tailings poses serious environmental and safety challenges, while the increasing shortage of traditional mineral admixtures such as fly ash and slag highlights the urgent need for sustainable alternatives. This study aims to develop a high-performance mineral admixture [...] Read more.

The large-scale accumulation of high-sulfur lead–zinc tailings poses serious environmental and safety challenges, while the increasing shortage of traditional mineral admixtures such as fly ash and slag highlights the urgent need for sustainable alternatives. This study aims to develop a high-performance mineral admixture using lead–zinc tailings characterized by high SO₃ content and low pozzolanic activity. The effects of four activation routes—mechanical grinding, wet magnetic separation, wet magnetic separation–mechanical grinding, and mechanical grinding–high-reactivity mineral admixture synergistic modification—were systematically compared in terms of tailings fineness, SO₃ reduction, and activity index. The results indicate that single mechanical grinding can achieve the fineness requirement of Grade II admixtures specified in GB/T 1596–2017 (45 μm residue ≤ 30%), but the 28-day strength activity index only reached 58.64%, and the SO₃ content remained above the standard limit. Wet magnetic separation effectively reduced the SO₃ content to below 3.5%, and the combined process yielded a product with an activity index of up to 74.51%. Further improvement was achieved through a “mechanical grinding–high-reactivity mineral admixture synergistic modification” process, incorporating fly ash (FA), ground granulated blast furnace slag (GGBS), and silica fume (SF). Among these, SF exhibited the most pronounced synergistic effect. The optimal mixture, composed of 85.19% ground tailings and 14.81% SF, achieved the highest 28-day activity index of 76.35%. This process enables full utilization of tailings while maintaining a simplified flow, lower energy consumption, and superior product performance. The findings provide a feasible and efficient technological route for the high-value utilization of high-sulfur tailings and contribute to promoting green mining and sustainable resource development. Full article

(This article belongs to the Special Issue Advances in Mine Backfilling Technology and Materials, 2nd Edition)

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55 pages, 23513 KB

Open AccessArticle

Controls, Expressions, and Discovery Potential of Gold Mineralization in the Central-Eastern Yilgarn Craton, Western Australia: New Insights from an Integrated Targeting Study

by Oliver P. Kreuzer, Bijan Roshanravan, Amanda J. Buckingham, Daniel P. Core, Brian A. Konecke, Daniel McDwyer and Roger Mustard

Minerals 2025, 15(12), 1255; https://doi.org/10.3390/min15121255 - 27 Nov 2025

Abstract

This paper presents the results of an integrated targeting study covering the central-eastern Archean Yilgarn Craton of Western Australia, a region renowned for its substantial gold endowment (>40 Moz Au). The cornerstones of this study included custom-built geophysical and remote sensing targeting tools, [...] Read more.

This paper presents the results of an integrated targeting study covering the central-eastern Archean Yilgarn Craton of Western Australia, a region renowned for its substantial gold endowment (>40 Moz Au). The cornerstones of this study included custom-built geophysical and remote sensing targeting tools, a new lithostructural interpretation of the area, a targeting model based on the mineral systems approach, and a best-practice mineral potential modeling (MPM) workflow employing five complementary modeling techniques. The geophysical targeting tools were used to identify proximity, association, and abundance relationships between gold mineralization and gravity ridges or edges, as well as 95th-percentile K/Th radiometric and remotely sensed goethite–clay–iron feature depth index ratio anomalies. The lithostructural interpretation revealed structural trends oblique or orthogonal to the NNW-SSE-striking greenstone belts, likely representing important structural controls on gold mineralization. Fry analysis, used to assess the spatial distribution of geological point patterns, showed similar directions of maximum gold occurrence alignment. Together, these observations proved to be strong predictors of gold prospectivity in the MPM component of this targeting study. The MPM not only identified most known gold occurrences but also highlighted several underexplored areas with significant potential. The highest-priority MPM targets represent roughly an order-of-magnitude reduction in search space, the hallmark of a well-performing and practically useful targeting methodology. Full article

(This article belongs to the Special Issue Structure and Origin of Gold Mineralization: From Primary to Placer Gold Deposits)

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16 pages, 2913 KB

Open AccessArticle

Development of an Extraction Process for Niobium Pentoxide from Columbite Using Sodium Carbonate and Boric Acid

by Ramon Silveira, Lucio Rosso Neto, Felipe Fardin Grillo, José Roberto de Oliveira, Matheus Vinicius Gregory Zimmermann, Mateus Milanez, Tiago Elias Allievi Frizon, Jorge Luis Coleti, Agenor De Noni, Jr. and Eduardo Junca

Minerals 2025, 15(12), 1254; https://doi.org/10.3390/min15121254 - 26 Nov 2025

Abstract

The aim of this study was to initiate the development of a route for the extraction of niobium oxide from columbite ore using sodium carbonate and boric acid. Initially, the columbite ore was characterized. Eight formulations were prepared to investigate the proportion of [...] Read more.

The aim of this study was to initiate the development of a route for the extraction of niobium oxide from columbite ore using sodium carbonate and boric acid. Initially, the columbite ore was characterized. Eight formulations were prepared to investigate the proportion of sodium carbonate to boric acid. The fusions were carried out at 900 °C for 60 min. Afterwards, magnetic separation was performed to remove the iron present in the formulations. From the non-magnetic fraction, water leaching was conducted to investigate the effects of temperature, time, and solid-to-liquid ratio. Finally, the product obtained from water leaching was calcined to obtain niobium oxide. The results indicated that the addition of boric acid contributed to reducing both viscosity and fusion temperature, favoring the release of niobium. The water leaching step showed an inverse dependence on the solid-to-liquid ratio, meaning that decreasing the solid content and increasing the water content favored the solubilization of niobium-containing phases. Temperature and time did not have a statistically significant effect on the leaching process. At the end of the route, niobium oxide was obtained as the final product, confirmed by X-ray diffraction and scanning electron microscopy. Full article

(This article belongs to the Special Issue New Extraction Processes for Critical Metals from Non-Metallurgical Resources)

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19 pages, 14036 KB

Open AccessArticle

Enhanced Antibiotic Removal via Adsorption–Photocatalysis Using a ZnO–TiO₂–Halloysite Nanocomposite

by Jairo R. Marques, Rodrigo P. Feitosa, Idglan S. de Lima, Luis H. Oliveira, Edson C. Silva-Filho, Francisco Franco, Juan A. Cecilia and Josy A. Osajima

Minerals 2025, 15(12), 1253; https://doi.org/10.3390/min15121253 - 26 Nov 2025

Abstract

A nanocomposite combining the photocatalytic activity of ZnO and TiO₂ with the adsorption capacity of halloysite was developed for the degradation of ciprofloxacin hydrochloride (CIP). Characterization was performed by UV-Vis diffuse reflectance spectrophotometry, X-ray fluorescence, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), [...] Read more.

A nanocomposite combining the photocatalytic activity of ZnO and TiO₂ with the adsorption capacity of halloysite was developed for the degradation of ciprofloxacin hydrochloride (CIP). Characterization was performed by UV-Vis diffuse reflectance spectrophotometry, X-ray fluorescence, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. The results revealed uniform dispersion of ZnO and TiO₂ particles on the halloysite surface and the formation of heterojunctions, contributing to efficient adsorption and photocatalytic degradation. XRD and XPS analyses confirmed the presence of Ti⁴⁺ in the anatase phase, supporting the high photocatalytic potential of the synthesized samples. Photodegradation tests of CIP (30 mg L⁻¹) showed that the 5Zn-Ti-Hal sample achieved the highest removal efficiency (71.45%), with a predominance of photocatalysis (42.57%) over adsorption (28.58%). Bioassays demonstrated a significant antibacterial effect against Staphylococcus aureus (50.35% inhibitory effect) and no toxicity to Artemia salina (100% survival). These results indicate that ZnO–TiO₂–halloysite nanocomposites are a promising green technology for aquatic remediation, offering efficient CIP degradation, antibiotic inactivation, and environmental safety. Full article

(This article belongs to the Special Issue Organo-Clays: Preparation, Characterization and Applications)

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24 pages, 5555 KB

Open AccessArticle

Non-Invasive Investigation of a 16th-Century Illuminated Scroll: Pigments, Fillers, and Metal-Based Decorations

by Lucilla Pronti, Martina Romani, Luca Lanteri, Francesco Bizzarri, Claudia Colantonio, Claudia Pelosi, Chiara Ruberto, Lisa Castelli, Anna Mazzinghi, Valeria Spizzichino and Mariangela Cestelli Guidi

Minerals 2025, 15(12), 1252; https://doi.org/10.3390/min15121252 - 26 Nov 2025

Abstract

The study and preservation of illuminated manuscripts, particularly miniatures on parchment, are crucial for understanding the artistic, cultural, and technological history of the past. This research investigates the materials used in a 16th-century illuminated scroll, analyzing both the miniatures and the written text [...] Read more.

The study and preservation of illuminated manuscripts, particularly miniatures on parchment, are crucial for understanding the artistic, cultural, and technological history of the past. This research investigates the materials used in a 16th-century illuminated scroll, analyzing both the miniatures and the written text through non-invasive techniques. A multi-analytical approach was applied, including optical microscopy, Hypercolorimetric Multispectral Imaging (HMI), infrared reflectography in the 950–1700 nm range, Fiber Optics Reflectance Spectroscopy (FORS), macro X-ray fluorescence (MA-XRF) spectroscopy, Raman spectroscopy, and External Reflection Fourier Transform Infrared (ER-FTIR) spectroscopy. These methods provided a comprehensive characterization of the painting materials’ chemical composition and the artistic techniques utilized, revealing new information on Renaissance materials and practices. The detected mineral pigments primarily include smalt, vermilion, lead white, and minium, which are consistent with materials commonly found in illuminated manuscripts. Aluminosilicate and calcite were identified as fillers or substrates utilized for organic dyes, particularly those generating pink hues. An uncommon finding was the green pigment, which was identified as copper hydroxynitrate. Furthermore, gold and silver were extensively employed in the decorative elements, both as metal foils and in shell pigment form. Finally, the capital letters were executed using smalt and vermilion, while the black text ink was characterized as iron gall ink, a composition typically employed on parchment supports. Full article

(This article belongs to the Special Issue Mineral Pigments: Properties Analysis and Applications)

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19 pages, 7523 KB

Open AccessArticle

Petrogenesis of Intermediate Rocks in Tethyan Himalaya Igneous Province (SE Tibet): The Role of Source Composition and Fractional Crystallization

by Shengsheng Chen and Haonan Jie

Minerals 2025, 15(12), 1251; https://doi.org/10.3390/min15121251 - 26 Nov 2025

Abstract

The origin of intermediate rocks within large igneous provinces (LIPs), which often exhibit a bimodal compositional distribution, remains poorly understood. To investigate the petrogenesis of such intermediate magmas within the Early Cretaceous Tethyan Himalaya igneous province in Tibet, we present a comprehensive study [...] Read more.

The origin of intermediate rocks within large igneous provinces (LIPs), which often exhibit a bimodal compositional distribution, remains poorly understood. To investigate the petrogenesis of such intermediate magmas within the Early Cretaceous Tethyan Himalaya igneous province in Tibet, we present a comprehensive study of zircon U–Pb geochronology, whole-rock geochemistry, and Nd isotopes for the tonalites from the Zhegucuo area. Zircon U–Pb dating yields a crystallization age of 130.81 ± 0.55 Ma. The rocks exhibit low Mg# and compatible element contents, indicating significant fractional crystallization of ferromagnesian minerals, plagioclase, and accessory minerals. Their homogeneous, near-chondritic ε_Nd(t) values (−0.34 to +0.01) preclude significant crustal contamination. Based on field relationships, geochemistry, and isotopic evidence, we conclude that the Zhegucuo tonalites were generated by extensive fractional crystallization of basaltic magmas. FC3MS and FCKANTMS systematics reveal a peridotitic component in the mantle source of the Zhegucuo mafic rocks. The exceptionally high values of these proxies of the Zhegucuo tonalites are attributed to extensive fractional crystallization of evolved magmas. Full article

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

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26 pages, 1288 KB

Open AccessReview

Critical Contribution of Biomass-Based Amendments in Mine Ecological Restoration: Properties, Functional Mechanisms, and Environmental Impacts

by Si-Mai Peng, Xin-Yue Li, Jia Xie, Wen-Hui Liu, Su-Xin Li, Jian-Lan Luo and Lei Zhao

Minerals 2025, 15(12), 1250; https://doi.org/10.3390/min15121250 - 26 Nov 2025

Abstract

Mining activities have caused widespread land degradation and contamination, affecting millions of hectares worldwide and posing persistent ecological risks. However, reclamation substrates are constrained by limited availability and compromised quality, which restricts their ability to fully support mine ecological restoration. Among various amendment [...] Read more.

Mining activities have caused widespread land degradation and contamination, affecting millions of hectares worldwide and posing persistent ecological risks. However, reclamation substrates are constrained by limited availability and compromised quality, which restricts their ability to fully support mine ecological restoration. Among various amendment materials, biomass-based amendments have been widely applied due to their broad availability, renewability, biodegradability, and low cost. In recent years, their role has expanded beyond simple nutrient supplementation to encompass multiple functions, including structural optimization, pollutant stabilization, and microbial regulation. This review highlights the valorisation of biomass-derived solid wastes as multifunctional amendments for mine ecological restoration. By converting agricultural and industrial wastes into green materials, these amendments improve substrate structure, stabilize heavy metals and organic pollutants, enhance nutrient cycling, and stimulate microbial activity. Potential risks, including nutrient leaching, secondary pollution, and greenhouse gas emissions, are critically assessed, with emphasis on their variability under different environmental conditions. By integrating functional benefits with ecological risks, this work underscores the critical role of biomass-based amendments as waste-to-resource strategies in advancing sustainable mine reclamation, contributing to circular economy goals, and supporting environmental engineering practices. Full article

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

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26 pages, 5845 KB

Open AccessArticle

Automated 3D Multivariate Domaining of a Mine Tailings Deposit Using a Continuity-Aware Geostatistical–AI Workflow

by Keyumars Anvari and Jörg Benndorf

Minerals 2025, 15(12), 1249; https://doi.org/10.3390/min15121249 - 26 Nov 2025

Abstract

Geochemical data from mine tailings are layered, compositional, and noisy, complicating automated domaining. This study introduces a continuity-aware workflow the Geostatistical k-means Recurrent Neural Network (GkRNN) that links compositional preprocessing and geostatistical continuity to sequence learning, allowing depth order and lateral context to [...] Read more.

Geochemical data from mine tailings are layered, compositional, and noisy, complicating automated domaining. This study introduces a continuity-aware workflow the Geostatistical k-means Recurrent Neural Network (GkRNN) that links compositional preprocessing and geostatistical continuity to sequence learning, allowing depth order and lateral context to influence final domain labels. The workflow begins with a centered log-ratio (CLR) transform, followed by construction of a spectral embedding derived from kernelized direct and cross variograms. Clustering is carried out in this embedded space, and depth sequences are regularized with a hidden Markov model (HMM) model and a long short-term memory (LSTM) network. When applied to a multivariate set of tailing drillholes, stratigraphically coherent zones were obtained, depthwise proportions were stabilized, and vertical as well as lateral semivariograms remained consistent with laminated material. Compared with k-means and Gaussian Mixture baselines, over-segmentation was reduced and the intended layered architecture was recovered in most drillholes. The result is a reproducible domaining workflow that enables clearer grade estimation and more transparent risk evaluation. Full article

(This article belongs to the Special Issue Advancements in Mineral Resource Characterization Using Machine Learning)

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19 pages, 3908 KB

Open AccessArticle

C₁₄-HSL Quorum Sensing Signal Molecules: Promoting Role in Chalcopyrite Bioleaching Efficiency

by Shiqi Chen, Wang Luo, Zexing Yao, Yiran Li, Xinhong Wu, Nazidi Ibrahim, Shadab Begum and Yili Liang

Minerals 2025, 15(12), 1248; https://doi.org/10.3390/min15121248 - 26 Nov 2025

Abstract

N-tetradecanoyl-L-homoserine lactone (C₁₄-HSL) is a long-chain signaling molecule belonging to acyl-homoserine lactones (AHLs), which is widely present in the quorum sensing (QS) system of Gram-negative bacteria. In this study, the effects of C₁₄-HSL on chalcopyrite bioleaching [...] Read more.

N-tetradecanoyl-L-homoserine lactone (C₁₄-HSL) is a long-chain signaling molecule belonging to acyl-homoserine lactones (AHLs), which is widely present in the quorum sensing (QS) system of Gram-negative bacteria. In this study, the effects of C₁₄-HSL on chalcopyrite bioleaching mediated by Acidithiobacillus ferrooxidans (A. ferrooxidans) were investigated. After cultivating A. ferrooxidans with different energy substrates and exploring the potential mechanisms of signal molecule production, chalcopyrite was selected as the energy substrate for further study. Molecular docking analysis revealed that the high binding affinity between AHL and the receptor protein AfeR in A. ferrooxidans was beneficial for the activation of transcription by the AfeR-AHL complex, promoting their biological impact. The variations in the physicochemical parameters of pH, redox potential, and copper ions revealed that after adding C₁₄-HSL, the leaching rate of chalcopyrite increased (1.15 times during the initial 12 days). Further analysis of the mechanism of extracellular polymers formation indicated that the presence of C₁₄-HSL could promote the formation of biofilms and the adhesion of bacteria, facilitating mineral leaching rate of A. ferrooxidans. This research provides a theoretical basis for regulating the biological leaching process of chalcopyrite and metal recovery using signaling molecules, which could also be used to control environmental damage caused by acid mine/rock drainage. Full article

(This article belongs to the Special Issue Hydrometallurgical Treatments of Copper Ores, By-Products and Waste)

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21 pages, 6913 KB

Open AccessArticle

Controls of Zeolite Development on Reservoir Porosity from Lower Permian Formations in Shawan and Its Adjacent Areas, Western Junggar Basin

by Houkuan Lv, Hao Kuang, Lei Zhang, Fangpeng Dou, Chun Li and Lang Pan

Minerals 2025, 15(12), 1247; https://doi.org/10.3390/min15121247 - 26 Nov 2025

Abstract

The Shawan Sag and its adjacent areas are rich in hydrocarbon resources. Moreover, the genesis and evolution patterns of zeolite cements in the sandy conglomerate reservoirs have resulted in diverse types of reservoir spaces, a complex composition, and significant heterogeneity. To investigate their [...] Read more.

The Shawan Sag and its adjacent areas are rich in hydrocarbon resources. Moreover, the genesis and evolution patterns of zeolite cements in the sandy conglomerate reservoirs have resulted in diverse types of reservoir spaces, a complex composition, and significant heterogeneity. To investigate their impact on reservoir quality, this study integrates core observations, thin-section petrography, scanning electron microscopy (SEM), whole-rock X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) for macro–micro comparative analysis of zeolite cement types, formation mechanisms, and pore systems in the Lower Permian strata of the Shawan Sag and adjacent areas. Research demonstrates that provenance exerts a control on type and origin of the diagenetic zeolites: In the Shawan Sag, zeolites form through hydration of volcanic glass in tuff, while adjacent areas develop zeolites via albitization of plagioclase derived from andesite. This genetic divergence drives pore differentiation: Zeolite (heulandite and laumontite) evolution in the Sag generates grain-edge fractures through cement volume shrinkage and crystalline water release. In contrast, the adjacent areas exhibit reservoir spaces dominated by dissolution pores, resulting from the dissolution of laumontite and calcite, along with a relatively higher overall rock porosity. Full article

(This article belongs to the Special Issue Geochronology, Geochemistry, and Tectonic Significance of Pyroclastic Rocks)

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34 pages, 10510 KB

Open AccessArticle

Evolutionary Model of the Sepid-Sarve Manto-Type Copper Mineralization, Doruneh Fault Volcanic-Plutonic Belt (Central Iran Domain, NE Iran): An Integrated Geological, Geochemical, Fluid-Inclusion and Stable O–S Isotope Study

by Morteza Esform, Hasan Zamanian, Urs Klötzli, Alireza Zarasvandi, Alireza Almasi and Mohammad Goudarzi

Minerals 2025, 15(12), 1246; https://doi.org/10.3390/min15121246 - 25 Nov 2025

Abstract

The Sepid-Sarve copper deposit is part of an Eocene volcano-sedimentary sequence located in the southern Sabzevar Zone. The copper mineralization occurs at the contact between pyroclastic and lava units with various limestone layers (including marly, Nummulitic, sandy, and clastic limestones). The ore minerals [...] Read more.

The Sepid-Sarve copper deposit is part of an Eocene volcano-sedimentary sequence located in the southern Sabzevar Zone. The copper mineralization occurs at the contact between pyroclastic and lava units with various limestone layers (including marly, Nummulitic, sandy, and clastic limestones). The ore minerals consist of malachite, azurite, chalcocite, digenite, cuprite, tenorite, covellite, and occasionally native copper. The associated hydrothermal fluids show moderate to high salinities, ranging from 3.08 to 13.38 wt.% NaCl equivalent, with homogenization temperatures between 90 and 356 °C, indicating fluid mixing during ore formation. Chalcocite is rarely accompanied by quartz, suggesting low silica content in the ore-forming fluids. The δ³⁴S values of sulfide samples from the Sepid-Sarve deposit range from −23.9 ± 0.3‰ to −2.9 ± 0.2‰, while δ³⁴S values of hydrothermal H₂S range from −24.1 ± 0.3‰ to −21.0 ± 0.3‰. The δ¹⁸O values of hydrothermal fluids associated with mineralization fall within the range of basaltic rocks, meteoric waters, and sedimentary rocks. Geochemical variations in major and trace elements suggest the involvement of continental crustal contamination in the magmatic evolution. The studied volcanic rocks fall within the calc-alkaline to shoshonitic fields, formed in a continental arc setting, and are derived from an enriched mantle source influenced by subduction-related fluids. These rocks are characterized by HREE depletion, moderate LREE enrichment, and a weak negative Eu anomaly. Based on the results, the Sepid-Sarve deposit is classified as a stratabound (Manto-type) copper sulfide deposit, formed in a volcano-sedimentary setting associated with a subduction-related magmatic arc environment. Full article

(This article belongs to the Special Issue Critical Mineral Exploration: Innovations, Challenges and Future Directions)

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21 pages, 3340 KB

Open AccessArticle

Zircon U-Pb-Hf Isotopes, Whole-Rock Geochemistry and Sr-Nd Isotopes of Early Neoproterozoic Intrusion in the Erguna Block, NE China: Petrogenesis and Tectonic Implications

by Zhanlong Li, Ji Feng, Tianyu Zhao, Yang Liu, Rui Wang, Yanan Zhang and Fuling Fan

Minerals 2025, 15(12), 1245; https://doi.org/10.3390/min15121245 - 25 Nov 2025

Abstract

The early crustal evolution of microcontinental fragments in the Central Asian Orogenic Belt remains poorly constrained. Among these fragments, the Erguna Block records extensive Neoproterozoic magmatism that provides key constraints on its tectono-magmatic development in relation to the Rodinia supercontinent cycle. To furthering [...] Read more.

The early crustal evolution of microcontinental fragments in the Central Asian Orogenic Belt remains poorly constrained. Among these fragments, the Erguna Block records extensive Neoproterozoic magmatism that provides key constraints on its tectono-magmatic development in relation to the Rodinia supercontinent cycle. To furthering constrain the Neoproterozoic magmatic evolution of the Erguna Block, an integrated investigation combining petrography, zircon U-Pb and Lu-Hf isotopic analyses, whole-rock geochemistry, and Sr-Nd isotope data was carried out on the newly recognized Fengshuishan intrusion in northern Alongshan. Zircon U-Pb ages of 810 ± 5 Ma and 807 ± 4 Ma were obtained from granitic samples, while the dioritic sample gave an age of 773 ± 2 Ma, representing a major Neoproterozoic magmatic episode. The 810–807 Ma granites show positive zircon εHf(t) (+0.09 to +12.1) and whole-rock εNd(t) (+0.50 to +1.77), suggesting derivation mainly from partial melting of Mesoproterozoic juvenile crust with minor contribution from mantle-derived materials. In contrast, ca. 773 Ma gabbroic diorite exhibits εHf(t) values of −1.23 to +4.3 and an εNd(t) value of +1.33, implying a contribution from an enriched mantle source. These Fengshuishan igneous rocks show A-type geochemical signatures, enriched in Rb, Th, and Pb but depleted in Ba, Sr, and Eu. Integrating these data with regional geological evidence, we infer that the Fengshuishan intrusion formed in an intraplate extensional regime, recording an important phase of crust–mantle interaction during the Neoproterozoic. These results expand the record of Neoproterozoic igneous rocks in the Erguna Block and offer new constraints on its role within the Rodinia supercontinent. Full article

(This article belongs to the Special Issue Selected Papers from the 7th National Youth Geological Congress)

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24 pages, 17438 KB

Open AccessArticle

The Relationship Between Tectono-Magmatism and Gold (Polymetallic) Deposits in the Northeastern Hunan Province, Jiangnan Orogen: Insight from Three-Dimensional Electrical Structures

by Chenggong Liu, Sheng Jin, Gaoyi Zhao, Chengliang Xie, Jian’en Jing, Yue Sheng, Hao Dong, Letian Zhang, Yaotian Yin and Wenbo Wei

Minerals 2025, 15(12), 1244; https://doi.org/10.3390/min15121244 - 25 Nov 2025

Abstract

The Northeastern Hunan Province (NEH), situated within the Central Jiangnan Orogen, hosts abundant Au-polymetallic deposits. However, the coupling mechanism between the deep tectono-magmatism and Au-polymetallic mineralization remains poorly understood. In this study, a three-dimensional (3D) resistivity model derived from 59 magnetotelluric (MT) stations [...] Read more.

The Northeastern Hunan Province (NEH), situated within the Central Jiangnan Orogen, hosts abundant Au-polymetallic deposits. However, the coupling mechanism between the deep tectono-magmatism and Au-polymetallic mineralization remains poorly understood. In this study, a three-dimensional (3D) resistivity model derived from 59 magnetotelluric (MT) stations is presented to investigate the lithospheric architecture and its relationship to Au-polymetallic mineralization. The model reveals three prominent mid-to-lower crustal conductors (3–30 Ω·m) at 15–35 km depth beneath Au-polymetallic deposits along NE faults. These anomalies are interpreted as source zones and pathways for magmatic-hydrothermal fluids during the Late Mesozoic tectono-magmatism, likely formed by the enrichment of graphite films and sulfides along faults, which thus account for the observed conductive features. Moreover, the model reveals a thinning electrical lithosphere–asthenosphere boundary (eLAB) at ~80 km depth beneath the Southeastern NEH, attributed to lithospheric delamination triggered by the rollback of the Paleo-Pacific plate. This delamination facilitated the upwelling and lateral migration of asthenospheric materials, which promoted intense extension and crust–mantle interaction. Consequently, metallic elements were extensively extracted from the crust and concentrated into large-scale Au-polymetallic deposits in the NEH. Integrating with previous geochemical study, a deep-seated magmatic underplating and MASH model is proposed as key drivers of Au-polymetallic enrichment in the NEH, effectively linking deep tectono-magmatism with shallow mineralization. From a rheological perspective, three low-viscosity zones within the mid-to-lower crust likely acted as both vertical conduits and deep sources for metallogenic fluids, providing favorable pathways for their migration and accumulation. Full article

(This article belongs to the Special Issue Geoelectricity and Electrical Methods in Mineral Exploration)

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15 pages, 8541 KB

Open AccessArticle

Application of Laser-Induced Breakdown Spectroscopy and Principal Component Analysis for Compositional Zoning of Liddicoatite Tourmaline from Anjanaboniona

by Nancy J. McMillan and Anna VanDusen

Minerals 2025, 15(12), 1243; https://doi.org/10.3390/min15121243 - 25 Nov 2025

Abstract

Tourmalines from the Anjanabonoina pegmatite field, Central Madagascar, exhibit some of the most complex multi-color zoning patterns known. These tourmalines are also rare because of their unusual Ca- and Li-rich liddicoatite composition. Liddicoatite specimens crystallize in miarolitic pockets in pegmatites, which periodically break [...] Read more.

Tourmalines from the Anjanabonoina pegmatite field, Central Madagascar, exhibit some of the most complex multi-color zoning patterns known. These tourmalines are also rare because of their unusual Ca- and Li-rich liddicoatite composition. Liddicoatite specimens crystallize in miarolitic pockets in pegmatites, which periodically break open and seal. Multivariate analysis of Laser-Induced Breakdown Spectroscopy (LIBS) spectra of an Anjanabonoina liddicoatite specimen allows evaluation of simultaneous changes in all elements during crystallization. LIBS is an optical emission technique in which photons emitted from a cooling laser plasma are diffracted and recorded as a spectrum. All elements present in the sample at concentrations above their inherent detection limits are represented by peaks in the spectrum. Principal Component Analysis of 123 LIBS spectra acquired in a core-to-rim traverse reveals six major compositional zones that suggest four stages of crystallization, the last three of which begin with the opening of the pocket and mixing of pegmatitic fluids with those from the metasedimentary host rocks. Full article

(This article belongs to the Special Issue Understanding Geological Processes through Laser-Induced Breakdown Spectroscopy Analysis)

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19 pages, 13161 KB

Open AccessArticle

Zircon U–Pb Ages and Geochemistry of Diaoluoshan Granite, Hainan Island: Implications for Late Cretaceous Tectonics in South China

by Chao Wang, Dingyong Liang, Changxin Wei, Mulong Chen, Zailong Hu and Changyan Lv

Minerals 2025, 15(12), 1242; https://doi.org/10.3390/min15121242 - 24 Nov 2025

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Abstract

Hainan Island has experienced a superposition of multiple phases of tectonic movements and magmatic activities, leading to numerous controversies regarding the genesis, spatiotemporal distribution, and tectonic setting of its Yanshanian granites. Accurately determining the characteristics of magmatic rocks during this period is crucial [...] Read more.

Hainan Island has experienced a superposition of multiple phases of tectonic movements and magmatic activities, leading to numerous controversies regarding the genesis, spatiotemporal distribution, and tectonic setting of its Yanshanian granites. Accurately determining the characteristics of magmatic rocks during this period is crucial for clarifying the regional tectonic evolution. This study focuses on Diaoluoshan granite in the southeastern part of Hainan Island. Through petrological, mineralogical, zircon U-Pb geochronological, and geochemical analyses, it aims to identify the genetic type, formation age, and magma source properties of this pluton, thereby revealing the Late Yanshanian tectonic setting of Hainan Island. The results show that the zircon U-Pb dating of Diaoluoshan granite yields an age of 102.5 ± 2.8Ma, indicating its formation in the late Early Cretaceous. This granite is a high-K calc-alkaline I-type granite, with silica (SiO₂) content ranging from 63.9% to 77.3%. The pluton exhibits significant negative anomalies of Ta, Nb, P, and Ti, as well as relatively obvious positive anomalies of Rb, Th, U, and K. The biotite in the granite has a magnesium oxide (MgO) content ranging from 12.84% to 13.13%, showing characteristics of crust–mantle material mixing. The magma of this pluton was derived from the partial melting of the lower continental crust mixed with the uprising and underplating mantle mafic magmas, driven by the subduction of the Paleo-Pacific Plate and its slab rollback. This study confirms that during the Late Yanshanian, Hainan Island was in an extensional rift environment driven by the subduction of the Paleo-Pacific Plate and its slab rollback, but without a well-developed volcanic front. It provides key geological evidence for the study of Yanshanian tectono-magmatic evolution in South China. Full article

(This article belongs to the Special Issue Igneous Rocks as Archives of Earth's Geological History: Magma Processes and Continental Crust Evolution)

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23 pages, 9894 KB

Open AccessArticle

Quantitative Characterization of Deep Shale Gas Reservoir Pressure-Solution and Its Influence on Pore Development in Cases of Luzhou Area in Sichuan Basin

by Demin Liang, Yonghong Fu, Yuqiang Jiang, Chao Luo, Xunxi Qiu, Ran Wen and Qinhong Hu

Minerals 2025, 15(12), 1241; https://doi.org/10.3390/min15121241 - 24 Nov 2025

Viewed by 121

Abstract

The phenomenon of pressure-solution (PS) is widespread in deep marine shale reservoirs of the Longmaxi Formation in the Sichuan Basin, affecting pore development. However, systematic reports on the study of PS in shale reservoirs are yet to be seen. This study performed large-field [...] Read more.

The phenomenon of pressure-solution (PS) is widespread in deep marine shale reservoirs of the Longmaxi Formation in the Sichuan Basin, affecting pore development. However, systematic reports on the study of PS in shale reservoirs are yet to be seen. This study performed large-field scanning electron microscopy, mineral quantitative identification, low-pressure gas adsorption, and high-pressure mercury injection experiments on shale cores from the Longmaxi Formation. The pore structure characteristics and the PS process of deep shale reservoirs were clarified, a semi quantitative analysis method for PS was constructed, and the influence of PS on pore development was explored. Our results demonstrate that PS is widely present in deep gas shale reservoirs, primarily manifesting in the form of mineral transformation and fusion, particularly involving clay and quartz minerals. This process alters the mineral composition and particle size of the shale reservoirs. A semi-quantitative analysis method for PS and the action strength parameter Q_P has been established, based on the mineral composition and particle size of shale reservoirs. This parameter exhibits a positive correlation with burial depth, water saturation, and quartz content. The primary effect of PS on pore development is that, as mineral transformation results in an elevation of quartz content and an increase in particle size, pore dimensions undergo compression and subsequently diminish. This underscores why shale reservoirs containing over 70% quartz are unfavorable for pore development. Therefore, when the water saturation in the Longmaxi Formation shale reservoir exceeds 40% and the quartz content surpasses 70%, significant risks are present in the exploration and development of shale gas. Full article

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

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17 pages, 12104 KB

Open AccessArticle

Investigation of the Gemological Characteristics and Types of Inclusions of Emeralds from Sumbawanga, Tanzania

by Yi Guo, Xiao-Yan Yu and Chen-Xi Li

Minerals 2025, 15(12), 1240; https://doi.org/10.3390/min15121240 - 23 Nov 2025

Viewed by 198

Abstract

Africa hosts numerous emerald deposits, among which Sumbawanga, located at the junction of Tanzania, Zambia, Congo, and Malawi, stands out as one of the significant localities. This study presents a comprehensive analysis of the gemological, spectroscopic, and inclusion characteristics of Sumbawanga (Tanzania) emerald [...] Read more.

Africa hosts numerous emerald deposits, among which Sumbawanga, located at the junction of Tanzania, Zambia, Congo, and Malawi, stands out as one of the significant localities. This study presents a comprehensive analysis of the gemological, spectroscopic, and inclusion characteristics of Sumbawanga (Tanzania) emerald samples utilizing techniques such as gem microscopy, UV-Vis-NIR spectroscopy, Raman spectroscopy, GEM-3000, and EPMA, etc. These emerald crystals look like rolled pebbles and display a bluish-green coloration. They contain fingerprint-like fluid inclusions, which occasionally encompass a circular bubble (the gas phase is CO₂). Sumbawanga emeralds are characterized by abundant mineral inclusions, including quartz, apatite, anhydrite, diaspore, chrysoberyl, rutile, hematite, and magnetite. Particularly diagnostic are the mineral inclusion of chrysoberyl twins and the assemblages of quartz and diaspore. Full article

(This article belongs to the Special Issue Gems Under the Microscope: New Insights into Mineral Structures and Properties)

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24 pages, 10775 KB

Open AccessArticle

Lithofacies-Controlled Pore Characteristics and Mechanisms in Continental Shales: A Case Study from the Qingshankou Formation, Songliao Basin

by Xinshu Huang, Zhiping Li, Xiangxue Han, Yongchao Wang and Yiyuan Guo

Minerals 2025, 15(12), 1239; https://doi.org/10.3390/min15121239 - 23 Nov 2025

Viewed by 141

Abstract

Pore systems in continental shales are controlled by lithofacies and show strong heterogeneity, which challenges shale oil development. The Qingshankou Formation in the Songliao Basin is a major shale oil play in China. Previous studies have focused on macroscopic reservoir properties, with limited [...] Read more.

Pore systems in continental shales are controlled by lithofacies and show strong heterogeneity, which challenges shale oil development. The Qingshankou Formation in the Songliao Basin is a major shale oil play in China. Previous studies have focused on macroscopic reservoir properties, with limited analysis of pore differences among lithofacies. This study integrates mineralogy, organic geochemistry, and multi-scale pore structure characterization to examine four typical lithofacies: argillaceous, siliceous, calcareous, and mixed shales. Results show that pore evolution in the Qingshankou Formation can be divided into five stages: immature (Ro < 0.6%), low maturity (0.6% < Ro ≤ 0.8%), middle maturity (0.8% < Ro ≤ 1.0%), high maturity (1.0% < Ro ≤ 1.2%), and over maturity (Ro > 1.2%). The overall pattern follows a “three declines and two increases” trend. Due to differences in mineral composition and organic matter (OM), each lithofacies displays dis-tinct pore characteristics, which further influence oil-bearing potential and mobility. Siliceous shale, rich in felsic minerals, exhibits well-preserved pores and a developed micro-fracture network, providing the largest pore volume and average diameter. This facilitates the storage and flow of free oil, making it the preferred exploration target. Argillaceous shale, characterized by abundant clay minerals and OM, supports micropore development and offers the highest specific surface area (SSA). This yields significant adsorbed oil potential, highlighting its value as a secondary exploration target. This study clarifies the lithofacial controls on pore development in continental shales, providing a scientific basis for predicting favorable intervals and optimizing exploration strategies in the Qingshankou Formation and analogous basins. Full article

(This article belongs to the Topic Reservoir Characteristics and Evolution Mechanisms of the Shale)

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19 pages, 3641 KB

Open AccessArticle

The Enrichment of Uranium in Marine Organic-Rich Overmature Shales: Association with Algal Fragments and Implications for High-Productivity Interval

by Guoliang Xie, Kun Jiao, Shugen Liu, Yuehao Ye, Jiayu Wang, Bin Deng, Juan Wu and Xiaokai Feng

Minerals 2025, 15(12), 1238; https://doi.org/10.3390/min15121238 - 23 Nov 2025

Viewed by 186

Abstract

Marine organic-rich shales frequently exhibit anomalously high uranium (U) concentrations, yet the mechanisms governing its enrichment in overmature formations like the Wufeng–Longmaxi shales remain unclear. This study examines the distribution and enrichment patterns of uranium in the Wufeng–Longmaxi shales in typical wells through [...] Read more.

Marine organic-rich shales frequently exhibit anomalously high uranium (U) concentrations, yet the mechanisms governing its enrichment in overmature formations like the Wufeng–Longmaxi shales remain unclear. This study examines the distribution and enrichment patterns of uranium in the Wufeng–Longmaxi shales in typical wells through integrated geochemical and geophysical analyses, supplemented by natural gamma spectral logging data. Key findings include: (1) Multiple (up to three) uranium enrichment events are identified within the Wufeng–Longmaxi sequence, consistently corresponding to shale gas sweet spots. (2) Uranium content shows a clear dependence on organic matter (OM) type, with algal fragments being the primary host of uranium, likely due to incorporation during early diagenesis. Pore-water redox conditions and pH further govern the reduction of U (U⁶⁺) and its subsequent sequestration into organic phases. (3) The equivalent vitrinite reflectance (ER_o) of uranium-rich shales is 0.11%–0.17% higher than that of non-uranium-rich shales, suggesting that uranium enrichment may slightly enhance OM thermal maturity. (4) Uranium distribution is collectively controlled by reducing conditions, volcanic eruptions (e.g., tuff layers), and OM type. Additionally, uranium enrichment provides chronostratigraphic markers that may aid in timing marine black shales. These findings thus offer a mechanistic understanding of uranium enrichment in overmature shales, with direct implications for targeting productive intervals in shale gas systems. Full article

(This article belongs to the Topic Reservoir Genesis and Quality Evolution in Hydrocarbon Systems)

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16 pages, 3342 KB

Open AccessArticle

Geoscientific Input Feature Selection for CNN-Driven Mineral Prospectivity Mapping

by Arya Kimiaghalam, Kyubo Noh and Andrei Swidinsky

Minerals 2025, 15(12), 1237; https://doi.org/10.3390/min15121237 - 23 Nov 2025

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Abstract

In recent years, machine learning techniques such as convolutional neural networks have been used for mineral prospectivity mapping. Since a diverse range of geoscientific data is often available for training, it is computationally challenging to select a subset of features that optimizes model [...] Read more.

In recent years, machine learning techniques such as convolutional neural networks have been used for mineral prospectivity mapping. Since a diverse range of geoscientific data is often available for training, it is computationally challenging to select a subset of features that optimizes model performance. Our study aims to demonstrate the effect of optimal input feature selection on convolutional neural network model performance in mineral prospectivity mapping applications. We demonstrate results from both exhaustive and algorithmic feature selection methods in the context of copper porphyry prospectivity modeling and analyze the performance and stability of optimally trained models. Using the QUEST dataset from central interior British Columbia, such a feature selection technique improves model performance by 6.8% over models that use all available features, yet consumes around 2.2% of the computational resources needed to exhaustively search for the optimal feature subset. Full article

(This article belongs to the Special Issue Feature Papers in Mineral Exploration Methods and Applications 2025)

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18 pages, 9082 KB

Open AccessArticle

Zircon U-Pb Dating and Geological Significance of Late Paleozoic Intrusive Rocks in the Khanbogd-Erdene Area, Southern Mongolia

by Chao Fu, Jun-Jian Li, Shuai Zhang, Peng Ji, Zhi-Cai Dang, Si-Yuan Li and Naidansuren Tungalag

Minerals 2025, 15(12), 1236; https://doi.org/10.3390/min15121236 - 23 Nov 2025

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Abstract

The Khanbogd-Erdene region in southern Mongolia is a globally important copper–polymetallic metallogenic province, hosting large to super-large deposits, such as Oyu Tolgoi and Tsagaan Suvarga. The area experiences frequent tectonic–magmatic activity, particularly Late Paleozoic subduction-related magmatism, which controls the occurrence of large-scale copper–polymetallic [...] Read more.

The Khanbogd-Erdene region in southern Mongolia is a globally important copper–polymetallic metallogenic province, hosting large to super-large deposits, such as Oyu Tolgoi and Tsagaan Suvarga. The area experiences frequent tectonic–magmatic activity, particularly Late Paleozoic subduction-related magmatism, which controls the occurrence of large-scale copper–polymetallic mineralization. This study focuses on the Late Paleozoic granitic intrusive rocks in the Khanbogd-Erdene region of southern Mongolia. Using LA-ICP-MS and SHRIMP dating techniques, precise zircon U–Pb ages were obtained for 10 samples. A total of 209 zircon grains from these 10 intrusive rocks were analyzed, with most cathodoluminescence (CL) images of zircon grains showing distinct oscillatory zoning. Th/U ratios ranging from 0.11 to 2.92 indicate they are magmatic. The younger group of granitic rocks yielded ages between 260.2 ± 1.2 Ma and 286.6 ± 0.9 Ma, indicating an Early Permian geological age. The other seven samples yielded older ages between 315.9 ± 1.8 Ma and 340.9 ± 0.9 Ma, indicating a Carboniferous geological age. These large-scale Carboniferous to Early Permian intrusive rocks in the Khanbogd-Erdene region are products of tectonic–magmatic activity during specific stages of crustal evolution. The findings provide reliable chronological data for regional tectonic–magmatic activity and offer new evidence for constraining the timing of the Variscan orogeny in southern Mongolia. Full article

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

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15 pages, 3942 KB

Open AccessArticle

Influence and Mechanism of 1-Dodecyl-3-methylimidazolium Bromide on the Flotation Behavior of Quartz and Feldspar in a Neutral System

by Siyu Chen, Yuan Chen, Guohua Gu, Xiang Yao and Huanxiao Hu

Minerals 2025, 15(12), 1235; https://doi.org/10.3390/min15121235 - 23 Nov 2025

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Abstract

Quartz and feldspar have similar physical, chemical, and surface properties. Effectively separating them in near-neutral systems has long been a challenging research focus. This study introduces 1-Dodecyl-3-methylimidazolium bromide (DMB), an ionic liquid, as a collector in a quartz–feldspar flotation separation system to investigate [...] Read more.

Quartz and feldspar have similar physical, chemical, and surface properties. Effectively separating them in near-neutral systems has long been a challenging research focus. This study introduces 1-Dodecyl-3-methylimidazolium bromide (DMB), an ionic liquid, as a collector in a quartz–feldspar flotation separation system to investigate its effects on the flotation behavior of quartz and feldspar. The interaction between the collector and the minerals is explained through zeta potential measurements, infrared spectroscopy analysis, and DFT calculations. The flotation test results indicate that DMB exhibits selective flotation separation properties enabling the separation of quartz from feldspar. Across the pH range of 3 to 11, DMB demonstrates high collection capability for quartz, but lower capability for feldspar. In particular, at pH levels of 7 to 8, the recovery difference between the two minerals exceeds 80%, achieving optimal selective separation. Mechanistic studies indicate that DMB primarily adsorbs on quartz and feldspar through electrostatic adsorption. The adsorption energy between DMB and quartz reaches −340.59 kJ/mol, forming a stable adsorption layer on the quartz surface. However, electrostatic repulsion arises over a broad area due to the large volume and cationic nature of DMB’s polar group and the exposed cationic Al sites on the feldspar surface, thereby hindering the interaction between DMB and feldspar. This research establishes the foundation for achieving efficient selective flotation separation of quartz and feldspar in a neutral system. Full article

(This article belongs to the Special Issue Advances in Process Mineralogy)

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28 pages, 4317 KB

Open AccessArticle

Evaluation of Pyrite Recovery via Bench-Scale Froth Flotation from a Sulfide Ore Deposit in Southwestern Spain

by Amina Eljoudiani, Moacir Medeiros Veras, Carlos Hoffmann Sampaio, Josep Oliva Moncunill and Jose Luis Cortina Pallas

Minerals 2025, 15(12), 1234; https://doi.org/10.3390/min15121234 - 23 Nov 2025

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Abstract

In recent decades, there has been an upsurge in focus on the extraction of pyrite from sulfide ore deposits due to its vital role in the process of metal extraction and environmental management. This study explores the flotation behavior of pyrite in sulfide [...] Read more.

In recent decades, there has been an upsurge in focus on the extraction of pyrite from sulfide ore deposits due to its vital role in the process of metal extraction and environmental management. This study explores the flotation behavior of pyrite in sulfide ores using mechanical-cell flotation. This study compared the performance of two commonly used flotation collectors, potassium butyl xanthate (KXT) and diethyl dithiophosphate (DTP), in the beneficiation of a sulfide ore from southwestern Spain. Statistical analysis performed using MiniTab 4.0 revealed that collector type, reagent dosage, and pulp pH were the principal factors affecting pyrite recovery. Under the tested conditions, KXT exhibited superior metallurgical performance and selectivity compared with DTP. The flotation kinetics demonstrate that the chemical was more efficacious throughout both the rougher and cleaner phases of the process. The findings robustly corroborate the notion that employing xanthate-based chemicals to enhance pyrite concentration facilitates metal extraction from the Sulfide Ore Deposit in southwestern Spain. The study sets out a basis for process growth, and it is proposed that further research be conducted under industrial water conditions to validate the findings. Full article

(This article belongs to the Special Issue Kinetic Characterization and Its Applications in Mineral Processing)

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21 pages, 8097 KB

Open AccessArticle

Detrital Zircon Geochronology of the Permian Sedimentary Rocks from the Western Ordos Basin: Implications for Provenance Variations and Tectonic Evolution

by Xiaochen Zhao, Yiming Liu, Zeyi Feng, Yingtao Chen, Delu Li, Jintao Li, Xiaoru Wei, Zigang Ning and Yirong Jiang

Minerals 2025, 15(12), 1233; https://doi.org/10.3390/min15121233 - 22 Nov 2025

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Abstract

The western Ordos Basin (OB) is situated at the junction of multiple tectonic units with distinct properties. The prolonged and complex tectonic interactions from adjacent tectonic units have resulted in diverse structural phenomena and intricate evolutionary history in this region. The late Paleozoic [...] Read more.

The western Ordos Basin (OB) is situated at the junction of multiple tectonic units with distinct properties. The prolonged and complex tectonic interactions from adjacent tectonic units have resulted in diverse structural phenomena and intricate evolutionary history in this region. The late Paleozoic represents a critical period for the transition of the tectonic regime in this area. However, due to the effects of intense later-stage modification, the late Paleozoic provenance system and paleogeomorphology of this region remain poorly constrained. Against this background, systematic fieldwork and detrital zircon geochronological analyses of the Youjingshan and Quwushan Permian sections were conducted to determine sediment provenance, and spatial variations in detrital zircon geochronological characteristics across different parts of the OB are further discussed. The results indicate that the detrital zircon age spectra of the Permian Dahuangou and Yaogou formations in the Youjingshan and Quwushan sections are dominated by late Paleozoic (250–360 Ma), early Paleozoic (360–500 Ma), and Paleoproterozoic (1600–2500 Ma) age populations. However, significant differences in age composition are also observed among different samples. This study proposes that the detritus of the Dahuangou Formation in the Youjingshan area was mainly derived from the Alxa Block (AB), while that from the Yaogou Formation was sourced from the Yinshan-Daqingshan-Wulashan Orogenic Belt (YDWOB). In contrast, the West Qinling Orogenic Belt (WQOB) and North Qilian Orogenic Belt (NQOB) were identified as the source areas for the Dahuangou and Yaogou Formations in the Quwushan area. Based on a comprehensive comparison of detrital zircon geochronological data of the Permian strata in the OB, three major provenance systems can be identified: the southwestern source area (WQOB and NQOB); the northwestern source area (YDWOB and AB); and the interior source area (YDWOB). During the Permian, the tectonic-sedimentary evolution of the OB was primarily controlled by the combined effects of the Paleo-Asian Ocean (PAO) to the north and the Paleo-Tethys Ocean (PTO) to the south. Differences in the timing and intensity of subduction/collision between the PAO and the PTO resulted in a general paleogeographic pattern of “higher in the north and lower in the south” in the OB. Full article

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

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35 pages, 3301 KB

Open AccessReview

Rare Earth Elements in Phosphate Ores and Industrial By-Products: Geochemical Behavior, Environmental Risks, and Recovery Potential

by Nourhen Omri, Radhia Souissi, Fouad Souissi, Christine Gleyzes, Noureddine Zaaboub, Houyem Abderrazak, Olivier F. X. Donard and Larbi Rddad

Minerals 2025, 15(12), 1232; https://doi.org/10.3390/min15121232 - 22 Nov 2025

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Abstract

Phosphate rock is a vital natural resource classified by the European Commission as a critical raw material (CRM), extensively mined for its agricultural, industrial, and technological applications. While primarily used in fertilizer production, phosphate deposits also contain significant concentrations of trace metals, notably [...] Read more.

Phosphate rock is a vital natural resource classified by the European Commission as a critical raw material (CRM), extensively mined for its agricultural, industrial, and technological applications. While primarily used in fertilizer production, phosphate deposits also contain significant concentrations of trace metals, notably rare earth elements (REE), which are essential for renewable energy, electronics, and defense technologies. In response to growing demand, the recovery of REE from phosphate ores and processing by-products, particularly phosphogypsum (PG), has gained international attention. This review provides a comprehensive analysis of the global phosphate industry, examining production trends, market dynamics, and the environmental implications of phosphate processing. Special focus is placed on the geochemical behavior and mineralogical associations of REE within phosphate ores and industrial residues, namely PG and purification sludge. Although often treated as waste, these by-products represent underexplored secondary resources for REE recovery. Technological advancements in hydrometallurgical, solvometallurgical, and bioleaching methods have demonstrated promising recovery efficiencies, with some pilot-scale studies exceeding 70%–80%. However, large-scale implementation remains limited due to economic, technical, and regulatory constraints. The circular economy framework offers a pathway to enhance resource efficiency and reduce environmental impact. By integrating innovative extraction technologies, strengthening regulatory oversight, and adopting sustainable waste management practices, phosphate-rich countries can transform environmental liabilities into strategic assets. This review concludes by identifying key knowledge gaps and suggesting future research directions to optimize REE recovery from phosphate deposits and associated by-products, contributing to global supply security, economic diversification, and environmental sustainability. Full article

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

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23 pages, 11200 KB

Open AccessArticle

Geochronology and Geochemistry of the Neoarchean Metabasalt in the Southern Liaoning Province, North China Craton: Implications on Regional Crustal Evolution

by Jialin Yang, Fulai Liu, Wei Wang, Pinghua Liu, Fang Wang, Jia Cai and Hong Yang

Minerals 2025, 15(12), 1231; https://doi.org/10.3390/min15121231 - 21 Nov 2025

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Abstract

The development of the continental crust during the Archean era is one of the key issues of geoscience. Determining the geological nature of the Archean terrane of the southern Liaoning Province (SLP) is fundamental to decipher the tectonic framework of the eastern North [...] Read more.

The development of the continental crust during the Archean era is one of the key issues of geoscience. Determining the geological nature of the Archean terrane of the southern Liaoning Province (SLP) is fundamental to decipher the tectonic framework of the eastern North China Craton (NCC) from the late Neoarchean to Paleoproterozoic. The Archean assemblage of the SLP is composed of metabasalt, deformed diorite, TTG, and granite. Zircon U-Pb and Lu-Hf data constrain that the metabasalt formed at 2.52 Ga and was metamorphosed at 2.49 Ga. Dioritic rocks, TTG (tonalite-trondhjemite-granodiorite) and granite formed between 2.53 and 2.48 Ga. More than 85% of analyzed zircon grains yield ε_Hf(t) values intermediate between coeval CHUR and depleted mantle (DM). Their single-stage (T_DM) Hf model ages are dominantly between 2.90 and 2.58 Ga with a peak at 2.76–2.66 Ga, suggesting that the Archean assemblages of the SLP were derived from short-lived crustal sources with limited contributions from older materials. Geochemistry and zircon Lu-Hf systems indicate that these metamafic rocks have N-MORB and island arc-like tholeiitic affinities. Similar basaltic associations were identified from the Wutai greenstone belt. Intra-oceanic subduction and back arc basin extension can be ascribed to the generation of associated MORB-like and arc-related basalt. Along with the closure of the SLP back arc basin, an unknown terrane accreted to the south of the Longgang block at the end of the Neoarchean. Full article

(This article belongs to the Special Issue Selected Papers from the 7th National Youth Geological Congress)

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Minerals, Volume 15, Issue 12 (December 2025) – 33 articles

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