Minerals

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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Graphical abstract

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

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

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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