Minerals

32 pages, 21563 KiB

Open AccessEditor’s ChoiceArticle

Diagenetic Classification—A New Concept in the Characterization of Heterogeneous Carbonate Reservoirs: Permian–Triassic Successions in the Persian Gulf

by Hamzeh Mehrabi, Saghar Sadat Ghoreyshi, Yasaman Hezarkhani and Kulthum Rostami

Minerals 2025, 15(7), 690; https://doi.org/10.3390/min15070690 - 27 Jun 2025

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Abstract

Understanding diagenetic processes is fundamental to characterizing heterogeneous carbonate reservoirs, where variations in pore structures and mineralogy significantly influence reservoir quality and fluid flow behavior. This study presents an integrated diagenetic classification approach applied to the upper Dalan and Kangan formations in the [...] Read more.

Understanding diagenetic processes is fundamental to characterizing heterogeneous carbonate reservoirs, where variations in pore structures and mineralogy significantly influence reservoir quality and fluid flow behavior. This study presents an integrated diagenetic classification approach applied to the upper Dalan and Kangan formations in the Persian Gulf. Utilizing extensive core analyses, petrographic studies, scanning electron microscopy (SEM) imaging, and petrophysical data, six distinct diagenetic classes were identified based on the quantification of key processes such as dolomitization, dissolution, cementation, and compaction. The results reveal that dolomitization and dissolution enhance porosity and permeability, particularly in high-energy shoal facies, while cementation and compaction tend to reduce reservoir quality. A detailed petrographic examination and rock typing, including pore type classification and hydraulic flow unit analysis using flow zone indicator methods, allowed the subdivision of the reservoir into hydraulically meaningful units with consistent petrophysical characteristics. The application of the Stratigraphic Modified Lorenz Plot facilitated large-scale reservoir zonation, revealing the complex internal architecture and significant heterogeneity controlled by depositional environments and diagenetic overprints. This diagenetic classification framework improves predictive modeling of reservoir behavior and fluid distribution, supporting the optimization of exploitation strategies in heterogeneous carbonate systems. The approach demonstrated here offers a robust template for similar carbonate reservoirs worldwide, emphasizing the importance of integrating diagenetic quantification with multi-scale petrophysical and geological data to enhance reservoir characterization and management. Full article

(This article belongs to the Special Issue Carbonate Petrology and Geochemistry, 2nd Edition)

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25 pages, 3819 KiB

Open AccessEditor’s ChoiceArticle

Evolution of Mafic Tungnárhraun Lavas: Transcrustal Magma Storage and Ascent Beneath the Bárðarbunga Volcanic System

by Tanya Furman, Denali Kincaid and Collin Oborn Brady

Minerals 2025, 15(7), 687; https://doi.org/10.3390/min15070687 - 27 Jun 2025

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Abstract

The Tungnárhraun basalts in southern Iceland record a transcrustal magma system formed during Holocene deglaciation. These large-volume (>1 km³) Early through Mid-Holocene lavas contain ubiquitous plagioclase feldspar macrocrysts that are too primitive to have grown from the host lavas. Thermobarometry based [...] Read more.

The Tungnárhraun basalts in southern Iceland record a transcrustal magma system formed during Holocene deglaciation. These large-volume (>1 km³) Early through Mid-Holocene lavas contain ubiquitous plagioclase feldspar macrocrysts that are too primitive to have grown from the host lavas. Thermobarometry based on plagioclase melt and clinopyroxene melt equilibrium reveals a transcrustal structure with at least three distinct storage regions. A lower-crustal mush zone at ~14–30 km is fed by primitive, low ⁸⁷Sr/⁸⁶Sr magmas with diverse Ti/K and Al/Ti signatures. Plagioclase feldspar growth is controlled by an experimentally determined pseudoazeotrope where crystals develop inversely correlated An and Mg contents. The rapid ascent of magmas to mid-crustal levels (~8–9 km) allows the feldspar system to revert to conventional thermodynamic phase constraints. Continued plagioclase growth releases heat, causing olivine and pyroxene to be resorbed and giving the magmas their characteristic high CaO/Al₂O₃ values (~0.8–1.0) and Sc contents (~52 ppm in matrix material). Mid-Holocene MgO-rich lavas with abundant plagioclase feldspar macrocrysts erupted directly from this depth, but both older and younger magmas ascended to a shallow-crustal storage chamber (~5 km) where they crystallized olivine, clinopyroxene, and plagioclase feldspar and evolved to lower MgO contents. The Sr isotope differences between the plagioclase macrocrysts and their carrier melts suggest that the fractionation involves the minor assimilation of country rock. This model does not require the physical disruption of an established and long-lived gabbroic cumulate mush. The transcrustal structures documented here existed in south Iceland at least throughout the Holocene and likely influenced much of Icelandic magmatism. Full article

(This article belongs to the Special Issue Trans-Crustal Evolution of Magmas: Clues from Thermodynamic and Geochemical Modelling, Thermo-Barometry and Experimental Petrology)

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31 pages, 34129 KiB

Open AccessEditor’s ChoiceArticle

Prediction of Buried Cobalt-Bearing Arsenides Using Ionic Leach Geochemistry in the Bou Azzer-El Graara Inlier (Central Anti-Atlas, Morocco): Implications for Mineral Exploration

by Yassine Lmahfoudi, Houssa Ouali, Said Ilmen, Zaineb Hajjar, Ali El-Masoudy, Russell Birrell, Laurent Sapor, Mohamed Zouhair and Lhou Maacha

Minerals 2025, 15(7), 676; https://doi.org/10.3390/min15070676 - 24 Jun 2025

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Abstract

The Aghbar-Bou Azzer East mining district (ABED) is located between the Bou Azzer East and Aghbar deposits. It is an area of approximately 7 km long towards ENE–WSW and 2 km wide towards N–S. In this barren area, volcano-sedimentary rocks are attributed to [...] Read more.

The Aghbar-Bou Azzer East mining district (ABED) is located between the Bou Azzer East and Aghbar deposits. It is an area of approximately 7 km long towards ENE–WSW and 2 km wide towards N–S. In this barren area, volcano-sedimentary rocks are attributed to the Ouarzazate group outcrop (Ediacarian age): they are composed of volcanic rocks (ignimbrite, andesite, rhyolite, dacite, etc.) covered by the Adoudou detritic formation in angular unconformity. Given the absence of serpentinite outcrops, exploration investigation in this area has been very limited. This paper aims to use ionic leach geochemistry (on samples of soil) to detect the presence of Co-bearing arsenides above hidden ore deposits in this unexplored area of the Bou Azzer inlier. In addition, a detailed structural analysis allowed the identification of four families of faults and fractures with or without filling. Three directional major fault systems of several kilometers in length and variable orientation in both the Cryogenian basement and the Ediacaran cover have been identified: (i) ENE–WSW, (ii) NE–SW, and (iii) NW–SE. Several geochemical anomalies for Co, As, Ni, Ag, and Cu are aligned along three main directions, including NE–SW, NW–SE, and ENE–WSW. They are particularly well-defined in the western zone but are only minor in the central and eastern zones. Some of these anomalies correlate with the primary structural features observed in the studied area. These trends are consistent with those known under mining exploitation in nearby ore deposits, supporting the potential for similar mineralization in the ABED. Based on structural analysis and ionic leach geochemistry, drilling programs were conducted in the study area, confirming the continuity of serpentinites at depth beneath the Ediacaran cover and the presence of Co–Fe-bearing arsenide ores. This validates the ionic geochemistry technique as a reliable method for exploring buried ore deposits. Full article

(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)

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24 pages, 4791 KiB

Open AccessEditor’s ChoiceArticle

Zircon out, Elpidite in: Deformation-Driven Zirconosilicate Evolution in Peralkaline Granites: A Case Study of the Papanduva Pluton (Brazil)

by Larissa P. Grangeiro, Frederico C. J. Vilalva, Silvio R. F. Vlach and Armando L. S. de Oliveira

Minerals 2025, 15(7), 667; https://doi.org/10.3390/min15070667 - 20 Jun 2025

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Abstract

The peralkaline granites of the Papanduva Pluton (South Brazil) display a remarkable facies dichotomy, with zircon dominant in massive facies and diverse zirconosilicates (Zr-Si) in foliated facies. This study employs petrography and mineral chemistry (major and trace elements) to elucidate the textural diversity [...] Read more.

The peralkaline granites of the Papanduva Pluton (South Brazil) display a remarkable facies dichotomy, with zircon dominant in massive facies and diverse zirconosilicates (Zr-Si) in foliated facies. This study employs petrography and mineral chemistry (major and trace elements) to elucidate the textural diversity and compositional evolution of these minerals. Three discrete zirconosilicate groups were identified: Na-rich elpidite (euhedral, vein-like, and granular varieties), Na-poor (Na,K)Zr-Si-I, and silica-rich (Na,K)Zr-Si-II. Contrary to the expected crystallization sequences, trace element data reveal that REE enrichment correlates with deformation intensity rather than paragenetic order, with vein-like aggregates along deformation features showing the highest REE concentrations. Statistical analysis demonstrates significant correlations between REE contents and alkali exchange patterns. We propose a three-stage evolutionary model involving magmatic crystallization, deformation-enhanced fluid interaction, and late-stage recrystallization, with a progressive evolution from Na-dominated to K-dominated conditions. This study provides new insights into closed-system fluid evolution in agpaitic environments and highlights deformation as a primary control on element mobility in peralkaline granitic systems. Full article

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

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18 pages, 6291 KiB

Open AccessEditor’s ChoiceArticle

Petrological Exploration of Magma Storage and Evolution Conditions at the Eastern Virunga Volcanic Province (Rwanda, East African Rift System)

by Fabio Colle, Teresa Trua, Serena Giacomelli, Massimo D’Orazio and Roberto Valentino

Minerals 2025, 15(7), 666; https://doi.org/10.3390/min15070666 - 20 Jun 2025

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Abstract

The Virunga Volcanic Province (VVP), located in the western branch of the East African Rift System, hosts a variety of alkaline lavas erupted from closely spaced volcanic centers. However, the magmatic system of this region, particularly in its eastern sector, remains insufficiently constrained. [...] Read more.

The Virunga Volcanic Province (VVP), located in the western branch of the East African Rift System, hosts a variety of alkaline lavas erupted from closely spaced volcanic centers. However, the magmatic system of this region, particularly in its eastern sector, remains insufficiently constrained. In this study, we present a petrological and geochemical investigation of basaltic to trachytic lavas from the eastern VVP. Thermobarometric analysis of mineral phases indicates that basalts originated from magma storage zones between 4 and 30 km deep, with crystallization temperatures of ~1200 °C and melt H₂O contents lower than 1 wt%. In contrast, more evolved magmas crystallized at similar depths, but at lower temperatures (~1050 °C) and higher H₂O contents, ranging from 2 to 4 wt%. Thermodynamic modelling suggests that extensive (up to 70%) fractional crystallization of an assemblage dominated by olivine, clinopyroxene, and plagioclase can produce the more evolved trachytic derivatives from basaltic parental melts. When integrated with previous studies from other VVP volcanoes, our findings deepen the understanding of the architecture of the magmatic system beneath the region, suggesting it resembles a well-developed multi-level plumbing system. Full article

(This article belongs to the Special Issue Trans-Crustal Evolution of Magmas: Clues from Thermodynamic and Geochemical Modelling, Thermo-Barometry and Experimental Petrology)

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34 pages, 12770 KiB

Open AccessEditor’s ChoiceArticle

Immiscibility in Magma Conduits: Evidence from Granitic Enclaves

by Ya Tian, Guanglai Li, Yongle Yang, Chao Huang, Yinqiu Hu, Kai Xu and Ji Zhang

Minerals 2025, 15(7), 664; https://doi.org/10.3390/min15070664 - 20 Jun 2025

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Abstract

Many granitic enclaves are developed in the volcanic channel of the Xiangshan volcanic basin. To explore their genesis, this study examined the petrography, geochemistry, LA-ICP-MS zircon U–Pb chronology, and zircon Hf isotopes of the granitic enclaves and compared them with the porphyroclastic lavas. [...] Read more.

Many granitic enclaves are developed in the volcanic channel of the Xiangshan volcanic basin. To explore their genesis, this study examined the petrography, geochemistry, LA-ICP-MS zircon U–Pb chronology, and zircon Hf isotopes of the granitic enclaves and compared them with the porphyroclastic lavas. In general, the granitic enclaves and porphyroclastic lavas have similar structures, and the rock-forming minerals and accessory minerals have relatively close compositions. In terms of rock geochemical characteristics, the granitic enclaves are richer in silicon and alkalis but have lower abundances of aluminum, magnesium, iron, and calcium than the porphyroclastic lavas. Rb, Th, K, Sm, and other elements are more enriched, whereas Ba, Ti, Nb, P, and other elements are more depleted. The granitic enclaves have lower rare earth contents (195.53 × 10⁻⁶–271.06 × 10⁻⁶) than the porphyroclastic lavas (246.67 × 10⁻⁶–314.27 × 10⁻⁶). The rare earth element distribution curves of the two are generally consistent, both right-leaning, and enriched with light rare earth patterns. The weighted average zircon U–Pb ages of two granitic enclave samples were 135.45 ± 0.54 Ma (MSWD = 0.62, n = 17) and 135.81 ± 0.60 Ma (MSWD = 0.40, n = 20), respectively, which are consistent with the weighted average age of a single porphyroclastic lava sample of 134.01 ± 0.53 Ma (MSWD = 2.0, n = 20). The zircons of the two kinds of rocks crystallize at almost the same temperature. The consistent trend of the rare earth element distribution curve of zircons in the granitic enclaves and the porphyroclastic lava samples indicates that the zircons of the two samples were formed in the same stage. The formation process of granitic enclaves may be that the lower crustal melt is induced to rise, and the crystallization differentiation occurs in the magma reservoir and is stored in the form of crystal mush, forming a shallow crystal mush reservoir. The crystal mush reservoir is composed of a large number of rock-forming minerals such as quartz, feldspar, and biotite, as well as accessory mineral crystals such as zircon and flowable intergranular melt. In the later stage of magma high evolution, a small and short-time magmatic activity caused a large amount of crystalline granitic crystal mush to pour into the volcanic pipeline. In the closed system of volcanic pipeline, the pressure and temperature decreased rapidly, and the supercooling degree increased, and the immiscibility finally formed pale granitic enclaves. Full article

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

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23 pages, 11386 KiB

Open AccessEditor’s ChoiceArticle

Tectonic Evolution of Wadi Hebran Area on the Suez Rift Eastern Flank, Sinai, Egypt

by Sherif Mansour, Amr Elkelish, Abdullah S. Alawam, Mohamed A. Gharib, Akihiro Tamura and Noriko Hasebe

Minerals 2025, 15(6), 655; https://doi.org/10.3390/min15060655 - 18 Jun 2025

Viewed by 391

Abstract

Continental rifts represent one of the most important settings geologically and economically. The Suez Rift represents more than 74% of the Egyptian crude oil. It represents the northern end of the Red Sea, which understanding is vital to reconstructing the tectonics, dynamics, and [...] Read more.

Continental rifts represent one of the most important settings geologically and economically. The Suez Rift represents more than 74% of the Egyptian crude oil. It represents the northern end of the Red Sea, which understanding is vital to reconstructing the tectonics, dynamics, and time–temperature history of the whole region. An effective method to reveal rift-related history is by studying its flanks, which are represented here by the Arabian-Nubian Shield Neoproterozoic basement rocks. We applied an approach integrating new fission-track thermochronology data, new time–temperature modeling, stratigraphic information, and geological knowledge, which has proven its effectiveness in such geological settings. The collected samples from the Wadi Hebran area on the eastern flank of the Suez rift showed two differentiated cooling histories: The first has a Carboniferous zircon fission-track and a Cretaceous apatite fission-track age, and the second has a Triassic zircon fission-track and an Oligocene–Miocene apatite fission-track age. The time–temperature history modeling supported four distinct cooling events activated through the Neoproterozoic post-accretion erosional event, Variscan tectonic event, Gondwana disintegration, and the Suez Rift initiation. The rock uplift that accompanied the Suez Rift reaches up to 4 km, explaining the extraordinary elevations of the Catherina region, and supports an active rift component in the southern segment of the Suez Rift eastern flank. Full article

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

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11 pages, 1410 KiB

Open AccessEditor’s ChoiceArticle

Theoretical Study on Impact of Chemical Composition and Water Content on Mechanical Properties of Stratlingite Mineral

by Daniel Tunega and Ali Zaoui

Minerals 2025, 15(6), 648; https://doi.org/10.3390/min15060648 - 16 Jun 2025

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Abstract

Stratlingite is known as one of the hydration products of aluminum-rich cements. Its microstructure and, consequently, mechanical properties, depend on the Al/Si ratio and hydration conditions. The layered structure of stratlingite is characterized as defected, with vacancies in the aluminosilicate layer. This study [...] Read more.

Stratlingite is known as one of the hydration products of aluminum-rich cements. Its microstructure and, consequently, mechanical properties, depend on the Al/Si ratio and hydration conditions. The layered structure of stratlingite is characterized as defected, with vacancies in the aluminosilicate layer. This study uses density functional theory calculations on different stratlingite models to show how chemical composition, water content, and structural defects affect its mechanical properties. The developed models represent structures with full occupancy, with little or no content of structural water, and with vacancies in the aluminosilicate layer. It was shown that the full occupancy models have the highest toughness and are strongly anisotropic. The calculated bulk modulus (B_H) of the models with full occupancy was about 40 GPa, being in the typical range for calcium aluminosilicate minerals. The water loss led to an increase in B_H by approximately 40% compared to the models with full occupancy. In contrast, the models with vacancies exhibited a decrease in B_H of about 30%. In models with the high silicon content (Al/Si ratio of 1/4), B_H, Young’s (E_H), and shear (G_H) moduli decreased in a range 15%–30% compared to the models with an Al/Si ratio of 2/3 of Al/Si. Finally, according to Pugh’s ratio (B_H/G_H), which serves as a criterion for brittle–ductile transition (1.8), the models with full occupancy exhibit a brittle behavior, whereas the defected structures are closer to ductile. This could explain the elastic behavior of stratlingite binder in concretes. Generally, the calculations showed that all investigated parameters (chemical composition, water content, and structural defects) have a significant impact on the mechanical properties of stratlingite minerals. Full article

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

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19 pages, 11500 KiB

Open AccessEditor’s ChoiceArticle

Continental Rift Driven by Asthenosphere Flow and Lithosphere Weakening by Flood Basalts: South America and Africa Cenozoic Rifting

by Ingo L. Stotz, Berta Vilacís, Jorge N. Hayek and Hans-Peter Bunge

Minerals 2025, 15(6), 644; https://doi.org/10.3390/min15060644 - 13 Jun 2025

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Abstract

Continental rifting is the process by which land masses separate and create new ocean basins. The emplacement of large igneous provinces (LIPs) is thought to have played a key role in (super) continental rifting; however, this relationship remains controversial due to the lack [...] Read more.

Continental rifting is the process by which land masses separate and create new ocean basins. The emplacement of large igneous provinces (LIPs) is thought to have played a key role in (super) continental rifting; however, this relationship remains controversial due to the lack of a clearly established mechanism linking LIP emplacement to continental fragmentation. Here, we show that plume flow links LIP magmatism to continental rifting quantitatively. Our findings are further supported by the sedimentary record, as well as by the mineralogy and petrology of the rocks. This study analyzes the early Cretaceous separation of West Gondwana into South America and Africa. Prior to rifting, Jurassic hiatuses in the stratigraphic record of continental sediments from both continents indicate plume ascent and the resulting dynamic topography. Cretaceous mafic dyke swarms and sill intrusions are products of major magmatic events that coincided with continental rifting, leading to the formation of large igneous provinces in South America and Africa, including the Central Atlantic Magmatic Province, Equatorial Magmatic Province, Paraná–Etendeka, and Karoo. It has been suggested that dyke intrusions may weaken the lithosphere by reducing its mechanical strength, creating structural weaknesses that localize extensional deformation and facilitate rift initiation. The sedimentary analysis and petrological evidence from flood basalt magmas indicate that plumes may have migrated from the depths toward the surface during the Jurassic and erupted during the Cretaceous. It is thought that the resulting fast plume flow, induced by one or more mantle plumes, generated a dynamic force that, in combination with lithospheric weakening from dyke intrusion, eventually rifted the lithosphere of West Gondwana. Full article

(This article belongs to the Special Issue Large Igneous Provinces: Research Frontiers)

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29 pages, 4559 KiB

Open AccessEditor’s ChoiceArticle

Revisiting the Permian Stratigraphy of the Kuznetsk Coal Basin (Siberia, Russia) Using Radioisotopic Data: Sedimentology, Biotic Events, and Palaeoclimate

by Vladimir V. Silantiev, Yaroslav M. Gutak, Marion Tichomirowa, Alexandra Käßner, Anna V. Kulikova, Sergey I. Arbuzov, Nouria G. Nourgalieva, Eugeny V. Karasev, Anastasia S. Felker, Maria A. Naumcheva, Aleksandr S. Bakaev, Lyubov G. Porokhovnichenko, Nikolai A. Eliseev, Veronika V. Zharinova, Dinara N. Miftakhutdinova and Milyausha N. Urazaeva

Minerals 2025, 15(6), 643; https://doi.org/10.3390/min15060643 - 13 Jun 2025

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Abstract

The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant [...] Read more.

The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant discrepancies between the updated ages and the previously accepted regional scheme (1982–1996). A comparison of regional stratigraphic units’ durations with estimated coal and siliciclastic sediment accumulation rates indicated that the early Permian contains the most prolonged stratigraphic hiatuses. The updated stratigraphic framework enabled re-evaluating the temporal sequence of regional sedimentological, volcano–tectonic and biotic events, allowing for more accurate comparison with the global record. Palaeoclimate reconstructions indicated that during the early Permian, the Kuznetsk Basin was characterised by a relatively warm, humid, and aseasonal climate, consistent with its mid-latitude position during the Late Palaeozoic Ice Age. In contrast, the middle-to-late Permian shows a transition to a temperate, moderately humid climate with pronounced seasonality, differing from the warmhouse conditions of low-latitude palaeoequatorial regions. The latest Lopingian reveals a distinct trend toward increasing dryness, consistent with global palaeoclimate signals associated with the end-Permian crisis. Full article

(This article belongs to the Special Issue Sedimentary Basins and Minerals)

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17 pages, 3986 KiB

Open AccessEditor’s ChoiceArticle

Geo-Identity of the Most Exploited Underground Obsidian Deposit in Mesoamerica: Cartography, Petrography, and Geochemistry of the Sierra de las Navajas, Hidalgo, Mexico

by Gerardo Alonso López-Velarde, Jesús Roberto Vidal-Solano and Alejandro Pastrana

Minerals 2025, 15(6), 629; https://doi.org/10.3390/min15060629 - 10 Jun 2025

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Abstract

The Sierra de las Navajas is a Late Pliocene volcanic complex with a rhyolitic composition and peralkaline affinity. It is located on the northeastern edge of the Trans-Mexican Volcanic Belt in the state of Hidalgo. Within this rocky massif lies Cerro de las [...] Read more.

The Sierra de las Navajas is a Late Pliocene volcanic complex with a rhyolitic composition and peralkaline affinity. It is located on the northeastern edge of the Trans-Mexican Volcanic Belt in the state of Hidalgo. Within this rocky massif lies Cerro de las Navajas, the site of the most intensively exploited archaeological obsidian deposit in Mesoamerica. Obsidian extraction in this area has been carried out through open-pit mining and unique underground mining. The geological identity of the deposit encompasses the origin, distribution, and petrological characteristics of the obsidian from Cerro de las Navajas, determined through detailed geological mapping, petrographic study, and geochemical analysis. The results reveal the obsidian deposit’s style as well as its temporal and spatial position within the eruptive evolution of the region. The deposit originated from a local explosive eruptive mechanism associated with the partial collapse of a lava dome, forming a Block and Ash Flow Deposit (BAFD). The obsidian blocks, exploited by different cultures, correspond to the pyroclastic blocks within this deposit, which can reach up to 1 m in diameter and are embedded in a weakly consolidated ash matrix. The BAFD was later buried by (a) subsequent volcanic events, (b) structural adjustments of the volcanic edifice, and (c) soils derived from the erosion of other volcanic units. This obsidian deposit was mined underground from the Early Formative period to the Colonial era by the cultures of the Central Highlands and colonized societies. Interest in the vitreous quality and exotic nature of obsidian lithics from the BAFD led to the development of a complex exploitation system, which was generationally refined by the Teotihuacan, Toltec, and Aztec states. Full article

(This article belongs to the Special Issue Characterization and Provenance Analysis of Ancient Stone Materials: Insights from Mineralogy, Petrology and Geochemistry)

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17 pages, 7055 KiB

Open AccessEditor’s ChoiceArticle

Effects of Grinding Parameters on Galena Particle Size Distribution and Flotation Performance

by Mengchi Guo, Yuankun Yang, Shengli Yu, Yanming Wu, Guohua Gu, Yanhong Wang, Qingke Li and Jianyu Chen

Minerals 2025, 15(6), 618; https://doi.org/10.3390/min15060618 - 9 Jun 2025

Viewed by 408

Abstract

The processing of low-grade, lead-containing practical ores requires fine grinding to liberate galena and enhance flotation recovery. The ball mill is still one of the most common approaches used in industry for fine grinding. This study investigated the effect of the grinding parameters [...] Read more.

The processing of low-grade, lead-containing practical ores requires fine grinding to liberate galena and enhance flotation recovery. The ball mill is still one of the most common approaches used in industry for fine grinding. This study investigated the effect of the grinding parameters in a ball mill on the fine grinding product of galena and on flotation performance. The grinding product had a particle size below 30 μm, which was classified into +25 μm, −25 + 10 μm, and −10 μm fractions. Grinding experiments showed that modifications to the grinding concentration, media proportion, and filling ratio exerted significant effects on the yields of the +25 μm and −10 μm fractions. Flotation experiments showed that the yield of −10 μm particles negatively affected the flotation performance of galena. Discrete element method simulation results revealed that an increase in the motion velocity of the media group enhanced attrition effects during fine grinding, promoting the generation of −10 μm particles. The higher yield of −10 μm particles facilitated a smaller contact angle and smaller agglomerate size, resulting in lower recovery. To optimize the particle size distribution and improve fine-grained galena flotation recovery, it is essential to reduce the attrition of the grinding media on the mineral. Full article

(This article belongs to the Special Issue Advances in the Theory and Technology of Physical Separation)

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16 pages, 6672 KiB

Open AccessEditor’s ChoiceArticle

Lithology and Macroscopic Coal Lithotype Identification of Coal-Bearing Measures Based on Elemental Mud Logging: A Case Study of the Eastern Ordos Basin Coal Seam

by Yuejiao Liu, Wenya Zhang, Fuqiang Lai, Mingyang Zhang, Honghua Sun, Zongsheng Zhou, Jianmeng Sun, Ruyue Wang and Shanshan Zheng

Minerals 2025, 15(6), 616; https://doi.org/10.3390/min15060616 - 9 Jun 2025

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Abstract

China is rich in coalbed methane (CBM) resources, and the key to realizing the scale and efficiency of CBM development is to build “engineering tools” for exploration and development continuously. Accurate calculation of rock components and precise identification of lithology and macroscopic coal [...] Read more.

China is rich in coalbed methane (CBM) resources, and the key to realizing the scale and efficiency of CBM development is to build “engineering tools” for exploration and development continuously. Accurate calculation of rock components and precise identification of lithology and macroscopic coal lithotypes of coal-bearing measures are the basis for the evaluation of CBM geological engineering. This paper proposes a method to identify the lithology and macroscopic coal lithotypes of coal-bearing measures based on elemental mud logging. Firstly, a coal seam demarcation line is constructed based on the elemental mud logging to divide the coal and non-coal seams. Secondly, the content of each component in the coal and non-coal seams is calculated. Finally, based on the results of the calculations, a method for recognizing the lithology of non-coal seams and macroscopic coal lithotypes of coal seams is constructed based on the combination of the S (sulfur) element innovatively. The calculation error of mineral and proximate analysis components is less than 10%, and the average accuracy of lithology and macroscopic coal lithotype identification is as high as 87%. The results can provide important technical guidance for the geological evaluation of coal-bearing measures and the selection of target seams. Full article

(This article belongs to the Special Issue Mineralogical and Geochemical Characteristics of Coal and Coal-Bearing Strata)

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18 pages, 8075 KiB

Open AccessEditor’s ChoiceArticle

Kinetic Aspects of Chrysotile Asbestos Thermal Decomposition Process

by Robert Kusiorowski, Anna Gerle, Magdalena Kujawa and Andrea Bloise

Minerals 2025, 15(6), 609; https://doi.org/10.3390/min15060609 - 5 Jun 2025

Viewed by 337

Abstract

Growing requirements in the field of environmental protection and waste management result in the need to search for new and effective methods of recycling various types of waste. From the perspective of technical and natural sciences, the disposal of hazardous waste, which can [...] Read more.

Growing requirements in the field of environmental protection and waste management result in the need to search for new and effective methods of recycling various types of waste. From the perspective of technical and natural sciences, the disposal of hazardous waste, which can lead to environmental degradation, is of utmost importance. A particularly hazardous waste is asbestos, used until recently in many branches of the economy and industry. Despite the ban on the production and use of asbestos introduced in many countries, products containing it are still present in the environment and pose a real threat. This paper presents the results of research related to the process of asbestos neutralization, especially the chrysotile variety, by the thermal decomposition method. Changes in the mineralogical characteristics of asbestos waste were studied using the following methods: TG-DTA-EGA, XRD, SEM-EDS and XRF. The characteristics of the chrysotile asbestos sample were determined before and after thermal treatment at selected temperatures. The second part of the study focuses on the kinetic aspect of this process, where the chrysotile thermal decomposition process was measured by two techniques: ex situ and in situ. This study showed that the chrysotile structure collapsed at approximately 600–800 °C through dehydroxylation, and then the fibrous chrysotile asbestos was transformed into new mineral phases, such as forsterite and enstatite. The formation of forsterite was observed at temperatures below 1000 °C, while enstatite was created above this temperature. From the kinetic point of view, the chrysotile thermal decomposition process could be described by the Avrami–Erofeev model, and the calculated activation energy values were ~180 kJ mol⁻¹ and ~220 kJ mol⁻¹ for ex situ and in situ processes, respectively. The obtained results indicate that the thermal method can be successfully used to detoxify hazardous chrysotile asbestos fibers. Full article

(This article belongs to the Special Issue Recycling of Industrial Waste for the Development of Sustainable Materials)

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16 pages, 1871 KiB

Open AccessEditor’s ChoiceArticle

Prediction of Circulation Load of Side-Flanged High-Pressure Grinding Rolls Closed-Circuit Crushing

by Nan Li, Lixia Li, Jiaqi Wang, Zhe Liu, Quan Feng, Qiang Zhang, Hui Liu, Bern Klein and Bing Li

Minerals 2025, 15(6), 603; https://doi.org/10.3390/min15060603 - 4 Jun 2025

Viewed by 313

Abstract

To enhance the performance of the combined high-pressure grinding roller (HPGR) and tower mill (TM) process for −1 mm particle size, this study addresses the key technical challenges of insufficient material quantity (<100 kg) and complex experimental procedures in HPGR closed-circuit crushing tests [...] Read more.

To enhance the performance of the combined high-pressure grinding roller (HPGR) and tower mill (TM) process for −1 mm particle size, this study addresses the key technical challenges of insufficient material quantity (<100 kg) and complex experimental procedures in HPGR closed-circuit crushing tests by proposing a novel circulating load prediction method based on the principle of mass balance and first-order crushing kinetics. Using a side-flanged HPGR WGM 6020 installation, systematic −1 mm HPGR closed-circuit crushing tests were conducted on seven different ore samples under three specific pressing forces, with detailed characterization of the dynamic variations in product size distribution, specific energy consumption, and circulating load during each cycle. The results demonstrate that within the specific pressing force range of 3.5 N/mm² to 4.5 N/mm² when the crushing process reaches equilibrium, the circulating load stabilizes between 100% and 200%, while the specific energy consumption is maintained within 1–2.5 kWh/t. Notably, at the specific pressing force of 4.5 N/mm², both the circulating load and specific energy consumption rapidly achieve stable states, with ore characteristics showing no significant influence on the number of cycles. To validate the model accuracy, additional samples were tested for comparative analysis, revealing that the deviations between the model-predicted −1 mm product content and circulating load and the experimental results were less than ±5%, confirming the reliability of the proposed method. Full article

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

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17 pages, 1581 KiB

Open AccessEditor’s ChoiceArticle

Advancing Flotation Process Modeling: Bayesian vs. Sklearn Approaches for Gold Grade Prediction

by Sheila Devasahayam

Minerals 2025, 15(6), 591; https://doi.org/10.3390/min15060591 - 31 May 2025

Viewed by 402

Abstract

This study explores Bayesian Ridge Regression and PyMC-based probabilistic modelling to predict the cumulative grade of gold based on key operational variables in gold flotation. By integrating prior knowledge and quantifying uncertainty, the Bayesian approach enhances both interpretability and predictive accuracy. The dataset [...] Read more.

This study explores Bayesian Ridge Regression and PyMC-based probabilistic modelling to predict the cumulative grade of gold based on key operational variables in gold flotation. By integrating prior knowledge and quantifying uncertainty, the Bayesian approach enhances both interpretability and predictive accuracy. The dataset includes variables such as crusher type, particle size, power, time, head grade, and collector type. Comparative analysis reveals that PyMC outperforms traditional Sklearn models, achieving an R² of 0.92 and an MSE of 102.37. These findings highlight the potential of Bayesian models for robust, data-driven process optimization in mineral processing. The higher cumulative gold grade observed for VSI products and PAX collector usage may be attributed to the superior liberation efficiency of VSI, which produces more angular and cleanly fractured particles, enhancing collector attachment. PAX, being a strong xanthate, shows high affinity for sulphide mineral surfaces, particularly under the flotation conditions used, thereby improving selectivity and recovery. Full article

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

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15 pages, 2858 KiB

Open AccessEditor’s ChoiceArticle

Surface Physicochemical Property Differences Between Gold-Bearing and Gold-Free Pyrite for Efficient and Clean Processing of Refractory Pyritic Gold Ores

by Xujian Chai, Runqing Liu, Wenchao Dong, Wei Sun and Shangyong Lin

Minerals 2025, 15(6), 577; https://doi.org/10.3390/min15060577 - 29 May 2025

Viewed by 361

Abstract

Selective separation of gold-bearing pyrite from gold-free pyrite through flotation to improve the gold-to-sulfur ratio in the feed can significantly enhance the throughput of autoclaves, thus achieving efficient and clean processing of refractory pyritic gold ores. To achieve this expectation, this study examined [...] Read more.

Selective separation of gold-bearing pyrite from gold-free pyrite through flotation to improve the gold-to-sulfur ratio in the feed can significantly enhance the throughput of autoclaves, thus achieving efficient and clean processing of refractory pyritic gold ores. To achieve this expectation, this study examined the surface physicochemical differences between gold-bearing and gold-free pyrite under flotation conditions using cyclic voltammetry, polarization curve testing, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) simulations. Electrochemical tests showed higher reactivity in gold-bearing pyrite, with reactivity positively correlated to gold content. XPS results indicated more oxidation products on gold-bearing pyrite surfaces under identical conditions. DFT simulations revealed that the presence of gold reduced the oxygen adsorption energy on the pyrite surface while enhancing interactions between oxygen atoms and sulfur and iron atoms. Based on these findings, the selective separation of gold-bearing and gold-free pyrite in the flotation process can be explored through pulp aeration pre-oxidation combined with collectors demonstrating selectivity toward barren pyrite (e.g., dithiocarbamate collectors). This study provides theoretical foundations for the efficient exploitation and utilization of refractory gold-bearing pyrite resources. Full article

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

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14 pages, 7485 KiB

Open AccessEditor’s ChoiceArticle

Supported Hybrid Amines Within Porous Aluminosilicate Clays with Natural Different Morphologies for Efficient CO₂ Capture

by Xiaoyu Li, Jie Chen, Wenqing Zhang, Chenyu Wang, Hui Ma, Kang Peng and Zheng Zhou

Minerals 2025, 15(5), 506; https://doi.org/10.3390/min15050506 - 9 May 2025

Viewed by 455

Abstract

The urgent need for efficient CO₂ capture technologies has driven research into amine-functionalized adsorbents, though existing methods face trade-offs between adsorption capacity and cycling stability. This study addresses these limitations by developing a novel hybrid modification strategy combining chemical grafting and physical [...] Read more.

The urgent need for efficient CO₂ capture technologies has driven research into amine-functionalized adsorbents, though existing methods face trade-offs between adsorption capacity and cycling stability. This study addresses these limitations by developing a novel hybrid modification strategy combining chemical grafting and physical impregnation on polymorphic kaolinite minerals. Through systematic acid leaching and hybrid grafting–impregnation amine functionalization, the adsorbents with hierarchically porous structures and optimized performances are synthesized. The tubular adsorbent (ATK-APTES-PEI) demonstrated exceptional performance, achieving a CO₂ uptake of 1.68 mmol/g at 75 °C under a 60% CO₂/40% N₂ mixed gas flow, with only 5.3% capacity loss after 10 adsorption–desorption cycles, significantly outperforming both rod-like (ARK-APTES-PEI, 1.55 mmol/g) and flake-like (AFK-APTES-PEI, 1.23 mmol/g) variants. The unique pore structure of ATK-APTES-PEI enables simultaneous high amine loading and maintained gas diffusion pathways, while the hybrid modification strategy synergistically enhances both adsorption capacity and stability by increasing active surface sites. These findings establish critical structure–property relationships for mineral-based adsorbents and demonstrate a scalable approach for industrial CO₂ capture applications. The work provides a blueprint for designing cost-effective, stable adsorbents using abundant clay minerals, bridging materials science with environmental engineering for sustainable carbon management solutions. Full article

(This article belongs to the Special Issue Clay Minerals and CO₂ Capture, Utilization and Storage)

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15 pages, 5368 KiB

Open AccessEditor’s ChoiceArticle

Radioiodide Sorption on Natural and Acid-Treated Zeolite

by Petr Belousov, Ekaterina Tyupina, Pavel Kozlov, Yulia Izosimova, Inna Tolpeshta, Tatiana Koroleva, Boris Pokidko, Victoria Krupskaya and Anastasia Rumyantseva

Minerals 2025, 15(5), 494; https://doi.org/10.3390/min15050494 - 7 May 2025

Viewed by 458

Abstract

This work is devoted to the study of the effect of acid treatment on the structural and textural properties of natural zeolite and its sorption activity with respect to radioiodide. To carry out the experiments, natural zeolite was treated with nitric acid of [...] Read more.

This work is devoted to the study of the effect of acid treatment on the structural and textural properties of natural zeolite and its sorption activity with respect to radioiodide. To carry out the experiments, natural zeolite was treated with nitric acid of various concentrations at 20 and 90 degrees. The following methods were used to study the samples: XRD, SEM, DTA, XRF, FTIR, BET, and CEC analyses. Experiments on the sorption and desorption of radioiodide were carried out. The obtained results indicate that acid treatment results in the gradual leaching of aluminum from the crystal lattice and a significant increase in the specific surface area and microporosity of the zeolite. At the same time, the morphology of clinoptilolite is not significantly changed. Additional studies have shown that acid treatment leads to the hydrophobization of zeolite channels and the formation of an amorphous aluminosilicate phase, which makes a significant contribution to the increase in the specific surface area and microporosity. It was found that, with an increase in the degree of dealumination of the zeolite, there is an increase in the sorption properties with respect to radioiodide. The maximum values of sorption capacity were obtained after treating the zeolite with a 1 M nitric acid solution at 90 °C. With a further increase in the concentration of acid, critical changes in the structure of the zeolite occur, leading to a sharp decrease in the sorption capacity. Iodide sorption is not associated with physical adsorption in the micropores of the zeolite and the newly formed amorphous phase. The main mechanism of the sorption appears to be the interaction with silanol and bridging hydroxyl groups on the surface of the zeolite and the amorphous aluminosilicate phase. Full article

(This article belongs to the Special Issue Zeolite: From a Boiling Stone to the Applicable Minerals in Various Industrial Processes: 2nd Edition)

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16 pages, 7745 KiB

Open AccessEditor’s ChoiceArticle

Investigation of a Novel Depressant for Flotation Separation of Chalcopyrite and Galena: Experiments and Adsorption Mechanisms

by Hong Zeng, Chongjun Liu, Tong Lu, Zehui Gao, Yangge Zhu, Chuanyao Sun, Zhiqiang Zhao, Guiye Wu, Ruidong Li and Jun Hu

Minerals 2025, 15(5), 454; https://doi.org/10.3390/min15050454 - 27 Apr 2025

Cited by 1 | Viewed by 362

Abstract

To reduce lead content in copper concentrates, this study developed a novel galena depressant, TA (thioureidoacetic acid). This study utilizes a synthetic mineral feed with fully liberated galena and chalcopyrite from separate sources to establish baseline separation conditions. The adsorption capability of TA [...] Read more.

To reduce lead content in copper concentrates, this study developed a novel galena depressant, TA (thioureidoacetic acid). This study utilizes a synthetic mineral feed with fully liberated galena and chalcopyrite from separate sources to establish baseline separation conditions. The adsorption capability of TA on galena surfaces was systematically investigated through micro-flotation tests, surface characterization, and first-principles calculations. Results demonstrate that TA effectively reduces galena recovery (from 82.92% to 12.29%) without compromising chalcopyrite flotation efficiency (>83.2% recovery) when using thionocarbamate (Z200) as the collector. FTIR and XPS analyses confirm that TA chemisorbs onto galena surfaces via its C=S and C=O functional groups. First-principles calculations reveal dual Pb-S and Pb-O bond formation during TA adsorption, resulting in stronger interfacial binding energy compared to Z200. This work establishes a molecular engineering framework for designing high-selectivity depressants. Full article

(This article belongs to the Special Issue Advances in Flotation of Copper, Lead and Zinc Minerals)

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24 pages, 13891 KiB

Open AccessEditor’s ChoiceArticle

Fertility of Gabbroic Intrusions in the Paleoproterozoic Lynn Lake Greenstone Belt, Manitoba, Canada: Insights from Field Relationships, Geochemical and Metallogenic Characteristics

by Xue-Ming Yang

Minerals 2025, 15(5), 448; https://doi.org/10.3390/min15050448 - 26 Apr 2025

Viewed by 573

Abstract

Magmatic nickel–copper–platinum group element (PGE) deposits hosted in mafic–ultramafic intrusions within volcanic arc systems are highly attractive targets for mineral exploration, yet their genesis remains poorly understood. This study investigates metagabbroic intrusions in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen [...] Read more.

Magmatic nickel–copper–platinum group element (PGE) deposits hosted in mafic–ultramafic intrusions within volcanic arc systems are highly attractive targets for mineral exploration, yet their genesis remains poorly understood. This study investigates metagabbroic intrusions in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen to identify the key factors, in the original gabbros, that control the formation of magmatic Ni-Cu-PGE deposits in volcanic arc systems. By examining the field relationships, geochemical and sulfur and oxygen stable isotope compositions, mineralogy, and structural fabrics, this study aims to explain why some intrusions host mineralization (e.g., Lynn Lake and Fraser Lake intrusions), whereas others remain barren (e.g., Ralph Lake, Cartwright Lake, and Snake Lake intrusions). Although both the fertile and barren gabbroic, likewise original, intrusions exhibit metaluminous, tholeiitic to calc-alkaline affinity with volcanic arc geochemical signatures, they differ significantly in shape, ranging from vertical and tube-like to tabular forms, reflecting distinct geological settings and magma dynamics. The gabbroic rocks of fertile intrusions exhibit erratic trace element profiles, lower (Nb/Th)_N and higher (Cu/Zr)_N ratios, as well as a larger range of δ³⁴S values than those in barren intrusions. Key factors influencing Ni-Cu-PGE mineralization include the degree of partial melting of the mantle, early sulfide segregation, and crustal contamination, particularly from volcanogenic massive sulfide deposits. These processes likely triggered sulfide saturation in the mafic magmas. Geochemical proxies, such as PGE concentrations and sulfur and oxygen stable isotopes, provide critical insights into these controlling factors. The results of this study enhance our understanding of the metallogenic processes responsible for the formation of magmatic Ni-Cu-PGE deposits in the gabbroic intrusions emplaced in an extensional setting due to slab rollback, during the geological evolution of the Lynn Lake greenstone belt, offering valuable guidance for mineral exploration efforts. Full article

(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)

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23 pages, 16107 KiB

Open AccessEditor’s ChoiceArticle

Utilizing Lineaments Extracted from Radar Images and Drainage Network to Evaluate the Mineral Potential of Au and Cu in the Bom Jardim Group (Neoproterozoic), Southern Brazil

by Marco Antonio Fontoura Hansen, César Augusto Moreira, Henri Masquelin, José Pedro Rebés Lima, Lenon Melo Ilha, Luiza Lima Alves, Sissa Kumaira and Ana Flávia da S. Araújo

Minerals 2025, 15(5), 436; https://doi.org/10.3390/min15050436 - 23 Apr 2025

Viewed by 875

Abstract

The exploration of gold and copper is essential for the sustainable development of mining worldwide and in Brazil, given the dependency on copper imports. This study aims to reassess and identify promising areas for sulfide prospecting in southern Brazil, with technologies, including radar [...] Read more.

The exploration of gold and copper is essential for the sustainable development of mining worldwide and in Brazil, given the dependency on copper imports. This study aims to reassess and identify promising areas for sulfide prospecting in southern Brazil, with technologies, including radar images (ALOS PALSAR) and software (PCI Geomatics CATALYST Professional Complete, version 2023, QGIS 3.38.1 (Grenoble), Spring 5.5.6, and Orient 3.20.0), for the extraction and processing of tectonic lineaments. The comparative analysis between these linear structures and the drainage networks allows for the assessment of alluvial gold minerals and disseminated copper in andesites, as observed in the abandoned Seival mines. The methods employed include the extraction of tectonic lineaments and the evaluation of mineral occurrences in the Hilário (volcanogenic) and Arroio dos Nobres (sedimentary) formations of the Bom Jardim Group (Neoproterozoic) and their drainage networks. As a result, this article concludes that the main tectonic alignment directions for copper and gold occurrences disseminated in andesites are predominantly E–W, N–S, N 5° W, N 58° W, N 62° E, and N 23° E, and for alluvial gold N–S and N 45° W. These results are crucial for reassessing abandoned mining areas and identifying the primary mineral orientations in rocks and the predominant orientation of alluvial deposits, serving as structural controls for discovering new mineral occurrences. It is concluded that geotechnologies have expanded the possibilities for study, enabling a more detailed analysis of tectonic lineaments and drainage systems and providing a valuable prospective guide for gold and copper mineral exploration. Full article

(This article belongs to the Special Issue Geophysical Signatures of Mineral Deposits in Tropical and Subtropical Settings)

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26 pages, 7042 KiB

Open AccessEditor’s ChoiceArticle

Thermodynamic Stability of Clay Minerals in Boreal Forest Soil and Its Relationship to the Properties of Soil Organic Matter

by Igor V. Danilin, Yulia G. Izosimova, Ruslan A. Aimaletdinov and Inna I. Tolpeshta

Minerals 2025, 15(4), 430; https://doi.org/10.3390/min15040430 - 20 Apr 2025

Viewed by 400

Abstract

This paper assesses the thermodynamic stability of clay minerals in the upper organo-mineral horizon of podzolic soil, as well as in the rhizosphere of Norway spruce (Picea abies (L.) H. Karst.) and Norway maple (Acer platanoides L.). Moreover, it determines the [...] Read more.

This paper assesses the thermodynamic stability of clay minerals in the upper organo-mineral horizon of podzolic soil, as well as in the rhizosphere of Norway spruce (Picea abies (L.) H. Karst.) and Norway maple (Acer platanoides L.). Moreover, it determines the impact of soil organic matter on the thermodynamic stability of clay minerals. Calculations of ΔG_f and the saturation index (SI) for clay minerals in laboratory experiments simulating soil conditions without soil moisture outflow allowed us to find out that the thermodynamic stability of clay minerals decreased in the series kaolinite > illite > vermiculite > chlorite. In the rhizosphere of spruce, kaolinite, vermiculite and illite have the lowest, and in the soil under maple-the highest thermodynamic stability, which is associated with differences in the properties of soil organic matter of rhizospheres of different tree species. Laboratory experiments on the sorption of soil humic acid (HA) on clay minerals demonstrated that sorbed HA decreased the thermodynamic stability of biotite and increased the thermodynamic stability of kaolinite and muscovite. Thermodynamic stability of clay minerals decreased with increased proportion of sorbed thermolabile organic matter. Full article

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

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22 pages, 17789 KiB

Open AccessEditor’s ChoiceArticle

Mafic Enclaves Reveal Multi-Magma Storage and Feeding of Shangri-La Lavas at the Nevados de Chillán Volcanic Complex

by Camila Pineda, Gloria Arancibia, Valentina Mura, Diego Morata, Santiago Maza and John Browning

Minerals 2025, 15(4), 418; https://doi.org/10.3390/min15040418 - 17 Apr 2025

Viewed by 654

Abstract

The Nevados de Chillán Volcanic Complex is one of the most active of the Southern Volcanic Zone. It is formed by NW-SE-aligned eruptive centers divided into two subcomplexes, namely Cerro Blanco (basaltic andesitic) and Las Termas (dacitic), and two satellite cones (to the [...] Read more.

The Nevados de Chillán Volcanic Complex is one of the most active of the Southern Volcanic Zone. It is formed by NW-SE-aligned eruptive centers divided into two subcomplexes, namely Cerro Blanco (basaltic andesitic) and Las Termas (dacitic), and two satellite cones (to the SW and NE of the main alignment). Our study of the Shangri-La volcano, which is located between the two subcomplexes, in alignment with the satellite cones, and which produced dacitic lavas with basaltic andesitic enclaves, sheds light on the compositional and structural diversity of the volcanic complex. Detailed petrography along with mineral chemistry allows us to suggest partial hybridization between the enclaves and the host lavas and that mixing processes are related to the generation of the Shangri-La volcano and to other volcanic products generated in the complex. This is supported by mixing trends between the enclaves and the most differentiated units from Las Termas. We argue the presence of two main magma storage areas genetically related to crustal structures. A dacitic reservoir (~950 °C) is fed along NW-SE structures, whereas a deeper mafic reservoir (>1100 °C) utilizes predominantly NE-SW structures. We suggest that the intersection between these sets of structures facilitates magma ascent and controls the Nevados de Chillán plumbing system dynamics. Full article

(This article belongs to the Special Issue Magmatic Evolution through Time of Volcanic Zones: Evidence from Isotopic, Geochemical and Geochronological Data of Eruption Products)

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50 pages, 21988 KiB

Open AccessEditor’s ChoiceArticle

Transforming LCT Pegmatite Targeting Models into AI-Powered Predictive Maps of Lithium Potential for Western Australia and Ontario: Approach, Results and Implications

by Oliver P. Kreuzer and Bijan Roshanravan

Minerals 2025, 15(4), 397; https://doi.org/10.3390/min15040397 - 9 Apr 2025

Viewed by 2020

Abstract

Here, we present holistic targeting models for lithium–cesium–tantalum (LCT) pegmatites in Western Australia, the world’s largest supplier of hardrock lithium ores, and Ontario, an emerging hardrock lithium mining jurisdiction. In this study, the LCT pegmatite targeting models, informed by a review of this [...] Read more.

Here, we present holistic targeting models for lithium–cesium–tantalum (LCT) pegmatites in Western Australia, the world’s largest supplier of hardrock lithium ores, and Ontario, an emerging hardrock lithium mining jurisdiction. In this study, the LCT pegmatite targeting models, informed by a review of this deposit type and framed in the context of a mineral system approach, served to identify a set of targeting criteria that are mappable in the publicly available exploration data for Western Australia and Ontario. This approach, which formed the basis for artificial intelligence (AI)-powered mineral potential modeling (MPM), using multiple, complimentary modeling techniques, not only delivered the first published regional-scale views of lithium potential across the Archean to Proterozoic terrains of Western Australia and Ontario, but it also delivered an effective framework for exploration and revealed hidden trends. For example, we identified a statistically verifiable proximity relationship between lithium, gold, and nickel occurrences and confirmed a significant size differential between LCT pegmatites in Western Australia and Ontario, with the former typically containing much larger resources than the latter. Overall, this regional-scale targeting study served to demonstrate the power of precompetitive, high-quality geoscience data, not only for regional-scale targeting but also for the development of camp-scale targets that have the resolution to be investigated using conventional prospecting techniques. Importantly, MPM does not generate ‘treasure maps’. Rather, MPM provides another tool in the ‘exploration toolbox’, and its output should be taken as the starting point for further investigations. Full article

(This article belongs to the Special Issue Critical Metal Minerals, 2nd Edition)

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18 pages, 2936 KiB

Open AccessEditor’s ChoiceArticle

Knowledge-Inference-Based Intelligent Decision Making for Nonferrous Metal Mineral-Processing Flowsheet Design

by Jiawei Yang, Chuanyao Sun, Junwu Zhou, Qingkai Wang, Kanghui Zhang and Tao Song

Minerals 2025, 15(4), 374; https://doi.org/10.3390/min15040374 - 3 Apr 2025

Viewed by 509

Abstract

With the increasing diversification of ore types and the complexity of processing techniques in the mining industry, traditional decision-making methods for mineral processing flowsheets can no longer meet the high efficiency and intelligence requirements. This paper proposes a knowledge graph-based framework for constructing [...] Read more.

With the increasing diversification of ore types and the complexity of processing techniques in the mining industry, traditional decision-making methods for mineral processing flowsheets can no longer meet the high efficiency and intelligence requirements. This paper proposes a knowledge graph-based framework for constructing a mineral-processing design knowledge base and knowledge reasoning, aiming at providing intelligent and efficient decision support for mining engineers. This framework integrates Chinese NLP models for text vectorization, optimizes prompt generation through Retrieval Augmented Generation (RAG) technology, realizes knowledge graph construction, and implements knowledge reasoning for nonferrous metal mineral-processing design using large reasoning models. By analyzing the genetic characteristics of ores and the requirements of processing techniques, the framework outputs reasonable flowsheet designs, which could help engineers save research time and labor in optimizing processes, selecting suitable reagents, and adjusting process parameters. Through decision analysis of the mineral-processing flowsheets for three typical copper mines, the framework demonstrates its advantages in improving process flowsheet design, and shows good potential for further application in complex mineral-processing environments. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Extractive Metallurgy of Base and Precious Metals)

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26 pages, 6453 KiB

Open AccessEditor’s ChoiceArticle

Petrological Studies and Geochemical Modelling of Water–Rock Interactions in the Grønnedal-Íka Alkaline Complex Generating Ikaite Deposition in Ikka Fjord, SW Greenland

by Sigríður María Aðalsteinsdóttir, Gabrielle J. Stockmann, Erik Sturkell, Enikő Bali, Guðmundur H. Guðfinnsson and Andri Stefánsson

Minerals 2025, 15(4), 373; https://doi.org/10.3390/min15040373 - 2 Apr 2025

Viewed by 523

Abstract

The Mesoproterozoic alkaline Grønnedal-Íka complex (1325 ± 6 Ma) is intruded into old Archean gneissic bedrock between Ikka Fjord and Kangilinnguit (Grønnedal) by Arsuk Fjord in Southwestern Greenland. This 8 × 2.8 km oval-shaped complex constitutes the oldest part of the Gardar Province, [...] Read more.

The Mesoproterozoic alkaline Grønnedal-Íka complex (1325 ± 6 Ma) is intruded into old Archean gneissic bedrock between Ikka Fjord and Kangilinnguit (Grønnedal) by Arsuk Fjord in Southwestern Greenland. This 8 × 2.8 km oval-shaped complex constitutes the oldest part of the Gardar Province, representing a failed continental rift across southern Greenland. It comprises outer rings of mainly nepheline syenites with a central plug of Fe- and Ca-rich carbonatites. Here, we present petrological data on the syenites and carbonatites combined with geochemical modelling of groundwater percolating through the Grønnedal-Íka complex and the secondary minerals and fluid chemistry arising from these fluid–rock reactions. The results show that modelling using input data of (1) meteoric water in a closed system with respect to atmospheric CO₂ can (2) dissolve the primary minerals of the syenites and carbonatites and (3) simulate the fluid chemistry of the natural sodium carbonate springs of 3–4 °C and pH 10–11 seeping up through fractures at the bottom of Ikka Fjord, which (4) leads to the deposition of nearly a thousand tufa columns of the cold carbonate mineral ikaite (CaCO₃•6H₂O). Our results thereby support the geochemical relationship between fluid–rock reactions inside the Grønnedal-Íka alkaline complex and the precipitation of ikaite in the shape of submarine tufa columns in Ikka Fjord. The modelling indicates that the groundwater itself can be supersaturated with respect to ikaite and provide the seed crystals that lead to the columnar growth of ikaite up to 20 m tall in the seawater of Ikka Fjord. Full article

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

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22 pages, 7574 KiB

Open AccessEditor’s ChoiceArticle

Evaluating Depositional Environment and Organic Matter Accumulation of Datangpo Formation in Central Hunan Province, South China

by Peng Jiao, Rong Xiao, Shimin Tan, Yu Xie, Hanqi Fang, Zhigang Wen and Zhanghu Wang

Minerals 2025, 15(4), 366; https://doi.org/10.3390/min15040366 - 31 Mar 2025

Viewed by 469

Abstract

The interglacial period of the Cryogenian glaciation is a pivotal interval in geological history, marked by two “Snowball Earth” events and the emergence of early animals. Currently, there is considerable debate regarding the paleo-oceanic environment and the dominant factors controlling organic matter enrichment. [...] Read more.

The interglacial period of the Cryogenian glaciation is a pivotal interval in geological history, marked by two “Snowball Earth” events and the emergence of early animals. Currently, there is considerable debate regarding the paleo-oceanic environment and the dominant factors controlling organic matter enrichment. Here, based on inorganic geochemical data and mineral composition from the Datangpo Formation in Xiangtan (South China), combined with previous research, we have analyzed the paleo-climate, redox condition, seawater restriction, and primary productivity across different sedimentary facies during this critical interval. The results exhibit that the Datangpo Formation can be divided into three members (Da1–Da3) based on lithology. Paleoclimatic proxies suggest the environment was relatively cold during the deposition of the Da-1 Member, while it was relatively warm and humid during the deposition of the Da 2–3 members. Compared to shallow water areas, deep-water areas experienced a more rapid transition in paleotemperature following the Sturtian glaciation event. Combining Mo-U elements, Ce_N/Ce*_N, and C_org/P ratios, the environment was characterized by an oxic environment during the early deposition period of the Datangpo Formation, then gradually transitioned to suboxic, and finally anoxic conditions. Furthermore, the decompression of terrestrial magma chambers led to intense volcanic/hydrothermal activity during the deglaciation period. Hydrothermal activity was most intense during the Da-1 depositional period, followed by Da-2, and gradually declined during Da-3 depositional period. Hydrothermal activity not only provided essential materials for the formation of Mn carbonate ores but also significantly enhanced the primary productivity by introducing large amounts of nutrients in the paleo-ocean. The primary productivity indicators (Ni/Al, Cu/Al) exhibited an obvious coupling with Ce_N/Ce*_N and C_org/P ratios in the Datangpo Formation, indicating that oxygen-rich environments were favorable for biological proliferation, thereby providing abundant organic matter. Anoxic conditions further facilitated the preservation of organic matter, which may be the primary factor driving organic matter enrichment in the Datangpo Formation. Full article

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

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26 pages, 12333 KiB

Open AccessEditor’s ChoiceArticle

Exploring High PT Experimental Charges Through the Lens of Phase Maps

by Balz S. Kamber, Marco A. Acevedo Zamora, Rodrigo Freitas Rodrigues, Ming Li, Gregory M. Yaxley and Matthew Ng

Minerals 2025, 15(4), 355; https://doi.org/10.3390/min15040355 - 28 Mar 2025

Viewed by 662

Abstract

High pressure and temperature (PT) experimental charges are valuable systems composed of minerals, often with quenched melt and/or fluid, synthesized to inform petrological processes deep within Earth. We explored the utility of phase mapping for the analysis of 5 GPa partial [...] Read more.

High pressure and temperature (PT) experimental charges are valuable systems composed of minerals, often with quenched melt and/or fluid, synthesized to inform petrological processes deep within Earth. We explored the utility of phase mapping for the analysis of 5 GPa partial melting experiments of peridotite. We further developed an open-source software workflow to generate phase maps, which is scanning electron microscope (SEM) instrument agnostic. Phase maps were constructed offline, combining high-quality back-scattered electron images and selected element maps, and compared and verified with maps obtained with commercial automated mineralogy software. One sub-solidus assemblage, one charge containing a small percentage of melt, and a melting experiment that displayed reactions (caused by a strong thermal gradient) were analyzed. For the sub-solidus experiment, the phase map returned an accurate modal mineralogy. For the quenched melt experiments, the phase map located low-abundance phases and identified the best-suited targets for chemical analysis. Using modal mineralogy of sub-regions on maps and mutual neighboring relationships, the phase maps helped to establish equilibrium conditions and verify melting reactions inferred from mass balance. We propose phase maps as valuable tools for documenting high PT charges, particularly for layered reaction experiments. We conclude with a set of recommended instrument settings for high-quality phase maps on small experimental charges. Full article

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

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31 pages, 7924 KiB

Open AccessEditor’s ChoiceReview

Techniques of Pre-Concentration by Sensor-Based Sorting and Froth Flotation Concentration Applied to Sulfide Ores—A Review

by Evandro Gomes dos Santos, Irineu Antonio Schadach de Brum and Weslei Monteiro Ambrós

Minerals 2025, 15(4), 350; https://doi.org/10.3390/min15040350 - 27 Mar 2025

Cited by 1 | Viewed by 1359

Abstract

The use of pre-concentration and optimization of concentration methods have been the focus of the modern mineral industry. Sensor-based sorting equipment and flotation are key players in that movement. This study provides an overview of the main sensor-based sorting techniques and their uses, [...] Read more.

The use of pre-concentration and optimization of concentration methods have been the focus of the modern mineral industry. Sensor-based sorting equipment and flotation are key players in that movement. This study provides an overview of the main sensor-based sorting techniques and their uses, focusing on sulfides, addressing performance analysis methodologies, and giving the advantages and limitations of the method. An overview of the flotation technique is also presented, covering its basic principles of operation, as well as its main applications in sulfides, its interactions with pre-concentration, and some opportunities and perspectives on the method, such as water reuse impacts, tailing reprocessing, etc. Case studies are presented addressing the influence of the techniques on each other and some future prospects for the mining sector, such as deep-sea mining (DSM) and the use of artificial intelligence (AI). Full article

(This article belongs to the Special Issue Mineral Processing Technologies of Low-Grade Ores)

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29 pages, 20187 KiB

Open AccessEditor’s ChoiceArticle

Applying Mineral System Criteria to Develop a Predictive Modelling for Epithermal Gold Mineralization in Northern New Brunswick: Using Knowledge-Driven and Data-Driven Methods

by Farzaneh Mami Khalifani, David R. Lentz, James A. Walker and Fereshteh Khammar

Minerals 2025, 15(4), 345; https://doi.org/10.3390/min15040345 - 27 Mar 2025

Viewed by 1041

Abstract

Using mineral prospectivity mapping (MPM), the mineral systems approach enables the identification of geological indicators linked to ore formation. This approach streamlines exploration by minimizing the time and cost required to identify areas with the highest mineral potential. With its extensive till cover [...] Read more.

Using mineral prospectivity mapping (MPM), the mineral systems approach enables the identification of geological indicators linked to ore formation. This approach streamlines exploration by minimizing the time and cost required to identify areas with the highest mineral potential. With its extensive till cover and dense forests limiting bedrock exposure, New Brunswick provides an ideal environment to test this approach. The New Brunswick portion of the Canadian Appalachians hosts a diverse range of gold deposits and occurrences that formed during various stages of the Appalachian orogeny. In northern New Brunswick and the adjacent Gaspé Peninsula, the Tobique–Chaleur Zone contains several orogenic and epithermal gold systems that are closely associated with a large-scale crustal fault and its offshoots, i.e., the long-lived trans-crustal Rocky Brook–Millstream Fault system. To identify favorable zones for epithermal gold mineralization in northwestern New Brunswick, this study employed MPM by translating key mineral system components—such as ore metal sources, fluid pathways, traps, and geological controls—into mappable criteria for regional-scale analysis. The data were modeled through the integration of knowledge-based and data-driven methods, including fuzzy logic, geometric average, and logistic regression approaches. The concentration–area (C–A) fractal model was applied to reclassify the final maps based on prospectivity values obtained from these three approaches, dividing the mineral prospectivity maps into six classes, with threshold values emphasizing high-favorability zones. The fuzzy overlay model had the highest predictive accuracy (AUC 0.97), followed by the geometric average model (AUC 0.93), whereas the logistic regression identified more tightly constrained high-potential zones. In the prospectivity models, known epithermal gold mineralization consistently overlaps with regions of high favorability. This suggests a positive result from the use of MPM, indicating that this approach could be applicable to other regions and types of ore deposits. Full article

(This article belongs to the Special Issue Smart Exploration of Critical Minerals: Integrating Multi-Source Data for Enhanced Mineral Prospectivity Mapping)

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17 pages, 23171 KiB

Open AccessEditor’s ChoiceArticle

Thermal Decomposition and Phase Transformation of Chrysotile in Asbestos-Containing Waste

by Chaewon Kim, Yumi Kim and Yul Roh

Minerals 2025, 15(4), 344; https://doi.org/10.3390/min15040344 - 27 Mar 2025

Cited by 3 | Viewed by 629

Abstract

In Korea, asbestos-containing waste (ACW) is disposed of in landfills. However, due to the limited landfill capacity and the potential health risks of asbestos contamination, alternative, safer disposal methods are needed. Heat treatment has been suggested as an alternative disposal method for ACW. [...] Read more.

In Korea, asbestos-containing waste (ACW) is disposed of in landfills. However, due to the limited landfill capacity and the potential health risks of asbestos contamination, alternative, safer disposal methods are needed. Heat treatment has been suggested as an alternative disposal method for ACW. Therefore, it is necessary to determine the optimal conditions for the thermal decomposition of chrysotile in ACW and reveal the mineralogical composition of heat-treated ACW. In this study, asbestos cement roof (ACR) and asbestos gypsum board (AGB) samples were heat-treated at 600, 700, 800, and 900 °C to identify the optimal heat treatment parameters to eliminate chrysotile fibers. The thermal, chemical, and mineralogical characteristics of the ACW were determined before and after heat treatment using multiple analytical methods. The ACR consisted of chrysotile, calcite, and ettringite, and the AGB consisted of chrysotile, gypsum, and calcite. After heat treatment at 900 °C, the ACR was mainly composed of cement component minerals and lime, while the AGB additionally contained anhydrite. SEM-EDS analysis confirmed the persistence of fibrous minerals in the ACW up to 800 °C. Furthermore, TEM-EDS analysis revealed hollow tubular morphology of chrysotile in the heat-treated ACR at up to 700 °C and in the heat-treated AGB at 600 °C. These results suggest that heat treatment at temperatures of at least 900 °C may be necessary for the complete thermal decomposition of chrysotile in ACW. Full article

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

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29 pages, 11095 KiB

Open AccessEditor’s ChoiceArticle

Uranium Mineral Particles Produced by Weathering in Sierra Peña Blanca, Chihuahua, Mexico: A Synchrotron-Based Study

by Cristina Hernández-Herrera, Jesús G. Canché-Tello, Yair Rodríguez-Guerra, Fabián G. Faudoa-Gómez, Diane M. Eichert, Konstantin Ignatyev, Rocío M. Cabral-Lares, Victoria Pérez-Reyes, Hilda E. Esparza-Ponce and María-Elena Montero-Cabrera

Minerals 2025, 15(4), 333; https://doi.org/10.3390/min15040333 - 22 Mar 2025

Viewed by 463

Abstract

Some of the largest Mexican uranium (U) deposits are located in Chihuahua. The most important is in Sierra Peña Blanca, northwest of the capital, which was explored and partially exploited in the 1980s. After the closure of activities, the mining projects were left [...] Read more.

Some of the largest Mexican uranium (U) deposits are located in Chihuahua. The most important is in Sierra Peña Blanca, northwest of the capital, which was explored and partially exploited in the 1980s. After the closure of activities, the mining projects were left exposed to weathering. To characterize the spread of U minerals towards the neighboring Laguna del Cuervo, sediment samples were collected in the main streams of the drainage pattern of the largest deposits. The U mineral fragments from the fine sand portion were extracted using fluorescence light at 365 nm. The morphology and elemental composition of these particles were analyzed by focused ion beam microscopy (FIB) and scanning transmission electron microscopy (STEM). The particle density in samples close to the U sources was quantified using gamma spectrometry. The highest density was 2500 part./g, and the lowest was 124 part./g. X-ray absorption spectroscopy (XAS) allowed us to establish via XANES the speciation of U in the U particles, confirming the U(VI) oxidation state, while the exploitation of the EXAFS spectrum put in evidence of the presence of uranophane. Finally, the Fe, Sr, and U distributions in the particle and its matrix were obtained via X-ray fluorescence microtomography (XRF-µCT). It was concluded that the particle is composed of uranophane, imbricated with quartz and other oxides. Full article

(This article belongs to the Special Issue Mineralogical and Chemical Characterization of Rocks, Soils, Sediments, and Water Containing Hazardous Substances)

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22 pages, 3192 KiB

Open AccessEditor’s ChoiceArticle

Effect of Domaining in Mineral Resource Estimation with Machine Learning

by Fırat Atalay

Minerals 2025, 15(4), 330; https://doi.org/10.3390/min15040330 - 21 Mar 2025

Cited by 1 | Viewed by 1004

Abstract

Machine learning (ML) is increasingly applied in earth sciences, including in mineral resource estimation. A critical step in this process is domaining, which significantly impacts estimation quality. However, the importance of domaining within ML-based resource estimation remains under-researched. This study aims to directly [...] Read more.

Machine learning (ML) is increasingly applied in earth sciences, including in mineral resource estimation. A critical step in this process is domaining, which significantly impacts estimation quality. However, the importance of domaining within ML-based resource estimation remains under-researched. This study aims to directly assess the effect of domaining on ML estimation accuracy. A copper deposit with well-defined, hard-boundary, low- and high-grade domains was used as a case study. Extreme Gradient Boosting (XGBoost), Support Vector Regression (SVR), and ensemble learning were employed to estimate copper distribution, both with and without domaining. Estimation performance was evaluated using summary statistics, swath plot analyses, and the quantification of out-of-range blocks. The results demonstrated that estimations without domaining exhibited substantial errors, with approximately 30% of blocks in the high-grade domain displaying values outside their expected range. These findings confirm that, analogous to classical methods, domaining is essential for accurate mineral resource estimation using ML algorithms. Full article

(This article belongs to the Special Issue Mineral Prospectivity Mapping (MPM) Using Multi-Source Datasets, Geo-Statistical Algorithms and Machine Learning Techniques)

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30 pages, 5838 KiB

Open AccessEditor’s ChoiceReview

Natural Mineral Materials for Enhanced Performance in Aqueous Zinc-Ion Batteries

by Peilin Chen, Qinwen Zheng, Ke Wang and Yingmo Hu

Minerals 2025, 15(4), 328; https://doi.org/10.3390/min15040328 - 21 Mar 2025

Viewed by 732

Abstract

Aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates for large-scale energy storage due to their inherent safety, cost-effectiveness, and environmental compatibility. However, challenges such as zinc -dendrite growth, hydrogen evolution reactions, and cathode dissolution hinder their practical application. To tackle these issues, [...] Read more.

Aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates for large-scale energy storage due to their inherent safety, cost-effectiveness, and environmental compatibility. However, challenges such as zinc -dendrite growth, hydrogen evolution reactions, and cathode dissolution hinder their practical application. To tackle these issues, a wide range of investigative approaches have been conducted to improve the performance of AZIBs. Recently, much attention has been paid to the application of natural mineral materials in AZIBs, since these low-cost minerals align well with the high sensitivity of battery costs in large-scale energy storage. This review systematically explores the application of natural mineral materials to address these issues across battery components, including protective layers on anodes and cathodes, functional films of separators, additives in electrolytes, etc. A multitude of minerals, such as halloysite, montmorillonite, attapulgite, diatomite, and dickite, are highlighted for their unique structural and physicochemical properties, including hierarchical porosity, ion-selective channels, and surface charge regulation. Finally, prospects for future research are discussed to construct AZIBs with a combination of excellent performance and cost efficiency and to bridge laboratory innovations with commercial viability. Full article

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

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36 pages, 9140 KiB

Open AccessEditor’s ChoiceArticle

The Geochemical Characteristics of Ore-Forming Fluids in the Jebel Stah Fluorite Deposit in Northeast Tunisia: Insights from LA-ICP-MS and Sr Isotope Analyses

by Chaima Somrani, Fouad Souissi, Radhia Souissi, Giovanni De Giudici, Eduardo Ferreira da Silva, Dario Fancello, Francesca Podda, José Francisco Santos, Tamer Abu-Alam, Sara Ribeiro and Fernando Rocha

Minerals 2025, 15(4), 331; https://doi.org/10.3390/min15040331 - 21 Mar 2025

Cited by 1 | Viewed by 1073

Abstract

The Zaghouan Fluorite Province (ZFP) encloses F-Ba(Pb-Zn) ores hosted within Jurassic carbonate series, in northeastern Tunisia. Critical breakthroughs on the Jebel Stah fluorite deposits, an MVT-style F-mineralization, have been made within the Lower Jurassic limestones along the Zaghouan Fault, which is a major [...] Read more.

The Zaghouan Fluorite Province (ZFP) encloses F-Ba(Pb-Zn) ores hosted within Jurassic carbonate series, in northeastern Tunisia. Critical breakthroughs on the Jebel Stah fluorite deposits, an MVT-style F-mineralization, have been made within the Lower Jurassic limestones along the Zaghouan Fault, which is a major target for mineralization. This study presents the first REE-Y analyses conducted by LA-ICP-MS on fluorites in Tunisia, and specifically on the fluorites of Jebel Stah deposit. This analytical technique provides highly accurate insights into the geochemical regime of mineralizing fluids and the related scavenging sources. Distinct geochemical characteristics between two fluorite generations (G1 and G2) were revealed. Fluorites (Fl2) from the early generation (G1) showed low ΣREE + Y (36.3 and 39.73 ppm, respectively). When normalized to chondrites, early fluorite G1 displayed a bell-shaped REE + Y pattern with a depletion in LREE relative to HREE and a slight MREE hump. Late fluorite (Fl3) generation (G2) displayed higher ΣREE + Y concentrations (77.43 ppm), but an almost similar REE pattern. Ce/Ce* ratios demonstrated strong negative Ce anomalies in all fluorites, while Eu/Eu* ratios indicated weak negative Eu anomalies. The positive Y anomaly observed in the REE + Y patterns of fluorites G1 and G2 suggests Y-Ho fractionation in the fluid system. Moreover, significant degrees of differentiation between terbium (Tb) and lanthanum (La) have been observed in all fluorite samples. The plot of fluorites from both fluorite generations on the Tb/La–Tb/Ca diagram gives evidence of the sedimentary hydrothermal origin of the ore-forming fluids in the Jebel Stah F-deposit. Sr isotopes show that the mineralizing fluids are radiogenic and deeply sourced basinal brines, whereas the small variation in ⁸⁷Sr/⁸⁶Sr ratios suggests a similar source for Sr in fluorites G1 and G2. These results allow us to conclude that the economic fluorite (G1) ore of Jebel Stah was deposited due to the interaction of the deeply sourced hydrothermal fluid with the carbonated host rocks (dolomitization, an increase in pH, and Ca activity), whereas the late fluorite (G2) is an accessory and could have resulted from the mixing of the hydrothermal fluid with shallow meteoric waters. Full article

(This article belongs to the Special Issue Mineralogical and Geochemical Characterization of Zn-Pb Ore Deposits: Insights into Their Genesis, Implications for Exploration, and Environmental Issues)

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31 pages, 16566 KiB

Open AccessEditor’s ChoiceArticle

The Role of Fluid Chemistry in the Diagenetic Transformation of Detrital Clay Minerals: Experimental Insights from Modern Estuarine Sediments

by Anas Muhammad Salisu, Abdulwahab Muhammad Bello, Abduljamiu O. Amao and Khalid Al-Ramadan

Minerals 2025, 15(3), 317; https://doi.org/10.3390/min15030317 - 19 Mar 2025

Viewed by 636

Abstract

The diagenetic transformation of detrital clay minerals significantly influences sandstone reservoir quality, with fluid chemistry and temperature playing key roles in dictating transformation pathways during burial diagenesis. While these processes are well-documented in basinal settings, the diagenetic alterations of sediments in dynamic environments [...] Read more.

The diagenetic transformation of detrital clay minerals significantly influences sandstone reservoir quality, with fluid chemistry and temperature playing key roles in dictating transformation pathways during burial diagenesis. While these processes are well-documented in basinal settings, the diagenetic alterations of sediments in dynamic environments like estuaries remain underexplored. This study investigates the impact of fluid composition on the transformation of modern estuarine sediments through hydrothermal experiments using sediments from the Gironde estuary, SW France. A range of natural and synthetic solutions including seawater (SW), 0.1 M KCl (SF1), 0.1 M NaCl, KCl, CaCl₂·2H₂O, MgCl₂·6H₂O (SF2), estuarine water (EW), and 0.1 M Na₂CO₃ (SF3) were used under temperatures from 50 °C to 250 °C for 14 days, with a fixed fluid-to-sediment ratio of 10:1. The results revealed distinct mineralogical transformations driven by fluid composition. Dissolution of detrital feldspars and clay materials began at lower temperatures (<100 °C). The authigenic formation of smectite and its subsequent illitization in K-rich fluids (SW, SF1) occurred between 150 °C and 250 °C, replicating potassium-driven illitization processes observed in natural sandstones. Additionally, chlorite formation occurred through the conversion of smectite in SF2 and EW. Geochemical analysis showed that SF2 produced Mg-rich chlorites, while EW yielded Fe-rich chlorites. This aligns with diagenetic trends in coastal environments, where Fe-rich chlorites are typically associated with estuarine systems. The resulting authigenic illite and chlorite exhibited morphological and chemical characteristics similar to those found in natural sandstones, forming through dissolution-crystallization and solid-state transformation mechanisms. In contrast to illite and chlorite, SF3 produced entirely different mineral phases, including halite and analcime (zeolite), attributed to the high alkalinity and Na-rich composition of the solution. These findings provide valuable insights into the role of fluid chemistry in the diagenetic alteration of modern sediments and their implications for the evolution of sandstone reservoirs, which is critical for energy exploration and transition. Full article

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

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23 pages, 4220 KiB

Open AccessEditor’s ChoiceReview

Utilization of Natural Mineral Materials in Environmental Remediation: Processes and Applications

by Di Xu, Yongkui Yang and Lingqun Gan

Minerals 2025, 15(3), 318; https://doi.org/10.3390/min15030318 - 19 Mar 2025

Viewed by 663

Abstract

The discharge of wastewater containing persistent organic pollutants presents significant ecological and health challenges due to their toxicity and resilience. Recent advances in advanced oxidation processes (AOPs) and other remediation mechanisms, notably utilizing natural mineral materials (NMMs), offer promising solutions to these challenges. [...] Read more.

The discharge of wastewater containing persistent organic pollutants presents significant ecological and health challenges due to their toxicity and resilience. Recent advances in advanced oxidation processes (AOPs) and other remediation mechanisms, notably utilizing natural mineral materials (NMMs), offer promising solutions to these challenges. NMMs, with their cost-effectiveness, accessibility, eco-friendly nature, non-toxicity, and unique structural properties, have shown significant promise in environmental remediation and could effectively replace conventional catalysts in related applications. These minerals enable the activation of oxidants, generating reactive oxygen species crucial for the degradation of pollutants. This article reviews the mechanisms of NMMs in various AOPs, including photocatalysis, Fenton-like reactions, and persulfate-activation-based processes, and discusses the potential of these materials in enhancing pollutant degradation efficiency, with a focus on the activation of persulfates and the photo-induced redox processes. The synergy between photocatalytic properties and catalytic activation provided by NMMs offers a robust approach to managing water pollution without the drawbacks of secondary waste production, thus supporting sustainable remediation efforts. Full article

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

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26 pages, 28443 KiB

Open AccessEditor’s ChoiceArticle

Diagenetic Evolution and Formation Mechanism of Middle to High-Porosity and Ultralow-Permeability Tuff Reservoirs in the Huoshiling Formation of the Dehui Fault Depression, Songliao Basin

by Siya Lin, Xiaobo Guo, Lili Li, Jin Gao, Song Xue, Yizhuo Yang and Chenjia Tang

Minerals 2025, 15(3), 319; https://doi.org/10.3390/min15030319 - 19 Mar 2025

Viewed by 551

Abstract

The fluid action mechanism and diagenetic evolution of tuff reservoirs in the Cretaceous Huoshiling Formation of the Dehui fault depression are discussed herein. The fluid properties of the diagenetic flow are defined, and the pore formation mechanism of the reservoir space is explained [...] Read more.

The fluid action mechanism and diagenetic evolution of tuff reservoirs in the Cretaceous Huoshiling Formation of the Dehui fault depression are discussed herein. The fluid properties of the diagenetic flow are defined, and the pore formation mechanism of the reservoir space is explained by means of thin sections, X-ray diffraction, electron probes, scanning electron microscopy (SEM), cathodoluminescence, and stable carbon and oxygen isotopic composition and fluid inclusion tests. The results reveal that the tuff reservoir of the Huoshiling Formation is moderately acidic, and the physical properties of the reservoir are characterized by middle to high porosity and ultralow permeability. The pore types are complex, comprising both primary porosity and secondary porosity, with dissolution pores and devitrification pores being the most dominant. Mechanical compaction and cementation are identified as key factors reducing reservoir porosity and permeability, while dissolution and devitrification processes improve pore structure and enhance pore connectivity. Diagenetic fluids encompass alkaline fluids, acidic fluids, deep-seated CO₊-rich hydrothermal fluids, and hydrocarbon-associated fluids. These fluids exhibit dual roles in reservoir evolution: acidic fluids enhance the dissolution of feldspar, tuffaceous materials, and carbonate minerals to generate secondary pores and improve reservoir quality, whereas alkaline fluids induce carbonate cementation, and clay mineral growth (e.g., illite) coupled with late-stage mineral precipitation obstructs pore throats, reducing permeability. The interplay among multiple fluid types and their varying dominance at different burial depths collectively governs reservoir evolution. This study underscores the critical role of fluid–rock interactions in controlling porosity–permeability evolution within tuff reservoirs. Full article

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

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43 pages, 41722 KiB

Open AccessEditor’s ChoiceArticle

Massive Dolomitization of Interior and Slope to Basin-Margin Facies of the Triassic Yangtze Platform Through Superposed Earth-Surface and Burial Mechanisms, Nanpanjiang Basin, South China

by Nathaniel S. Ledbetter Ferrill, Xiaowei Li, Josephine Tesauro, Madison Sears, George M. Bradley, Arianna Hilbert, Eryn Carney, Justice Saxby, Neda Mobasher, Brian M. Kelley, E. Troy Rasbury, Kathleen M. Wooton, Jason D. Kirk, John A. Luczaj and Daniel J. Lehrmann

Minerals 2025, 15(3), 324; https://doi.org/10.3390/min15030324 - 19 Mar 2025

Viewed by 779

Abstract

Triassic strata of the Yangtze Platform at Guanling contain a dolomitized interior, undolomitized margin, and partially dolomitized slope to basin margin. Dolomitized microbial laminate caps of peritidal cycles and massive dolomite with associated evaporite nodules and solution collapse breccias are consistent with penecontemporaneous [...] Read more.

Triassic strata of the Yangtze Platform at Guanling contain a dolomitized interior, undolomitized margin, and partially dolomitized slope to basin margin. Dolomitized microbial laminate caps of peritidal cycles and massive dolomite with associated evaporite nodules and solution collapse breccias are consistent with penecontemporaneous tidal flat and evaporative dolomitization in the platform interior. The preferential dolomitization of the slope and basin margin (up to 7 km basinward of the margin), dolomitization along fractures, and selective dolomitization of the matrix in slope breccia that diminishes toward the margin are interpreted to have resulted from the incursion of basin-derived fluids during burial. Integrated analysis of fluid-inclusion microthermometry, oxygen, carbon, and strontium isotopes, trace element geochemistry, U-Pb age dates of carbonate phases, and burial history support the recrystallization of interior dolomite and slope to basin-margin dolomitization by brines at high temperatures during burial. The Yangtze Platform at Guanling provides an excellent example of widespread stratiform dolomitization resulting from the superposition of multiple mechanisms, including penecontemporaneous dolomitization by evaporative seawater brines, high-temperature dolomitization of the slope and basin margin by basinal brines, and high-temperature recrystallization of dolomite by brines during burial. This study provides an example that suggests that widespread stratiform dolomite may result from superposed Earth surface and high-temperature burial dolomitization processes and provides a valuable analog for other carbonate platforms in which the margin remains undolomitized while the interior and basin margin are dolomitized. Similar mechanisms likely contributed to the widespread dolomitization of platforms across the Nanpanjiang and Sichuan basins. Full article

(This article belongs to the Special Issue Paleoenvironment Evolution Proxy in Carbonates: Sedimentary Geochemistry)

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12 pages, 2785 KiB

Open AccessEditor’s ChoiceArticle

Crystal Chemistry, High-Pressure Behavior, Water Content, and Thermal Stability of Natural Spodumene

by Yuhui Jiang, Jiayi Yu, Yuanze Ouyang, Li Zhang, Xiaoguang Li, Zhuoran Zhang and Yunxuan Li

Minerals 2025, 15(3), 307; https://doi.org/10.3390/min15030307 - 16 Mar 2025

Viewed by 615

Abstract

Spodumene (LiAlSi₂O₆) is a member of pyroxene-group minerals. It has the highest theoretical lithium abundance among all of the Li-bearing minerals. In the present work, in situ high-pressure Raman spectroscopic investigation of natural spodumene have been conducted up to [...] Read more.

Spodumene (LiAlSi₂O₆) is a member of pyroxene-group minerals. It has the highest theoretical lithium abundance among all of the Li-bearing minerals. In the present work, in situ high-pressure Raman spectroscopic investigation of natural spodumene have been conducted up to 19.04 GPa. Unheated spodumene and spodumene recovered after heat treatments (up to 1000 °C) have also been analyzed by X-ray diffraction and infrared spectroscopy. The results indicate that spodumene, after the displacive C2/c–P2₁/c transformation triggered at ~3.2 GPa, remains stable at pressures up to 19 GPa at ambient temperature without undergoing decomposition, amorphization, or a second phase transition. The major OH bands of the spodumene samples are observed within the wavenumber range of 2580–3220 cm⁻¹, implying a strong hydrogen bond interaction. The water content of the spodumene is estimated to be 19–97 ppm wt. H₂O based on the integrated absorption area of the OH bands. The FTIR analysis of the spodumene samples recovered after heat treatments implies that spodumene can retain a significant amount of water (up to ~100 ppm H₂O by weight) under high-temperature conditions up to 1000 °C. This suggests that spodumene in subducted slabs is unlikely to undergo dehydration at temperatures below 1000 °C, and is therefore not expected to trigger partial melting. Thus, spodumene may serve as a key carrier for Li, transporting it into the deep mantle without releasing Li into melts during subduction. Full article

(This article belongs to the Special Issue High-Pressure and High-Temperature Mineral Physics)

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21 pages, 8306 KiB

Open AccessEditor’s ChoiceArticle

Magmatic–Hydrothermal Processes of the Pulang Giant Porphyry Cu (–Mo–Au) Deposit, Western Yunnan: A Perspective from Different Generations of Titanite

by Mengmeng Li, Xue Gao, Guohui Gu and Sheng Guan

Minerals 2025, 15(3), 263; https://doi.org/10.3390/min15030263 - 3 Mar 2025

Viewed by 730

Abstract

The Yidun island arc was formed in response to the Late Triassic westward subduction of the Ganzi–Litang oceanic plate, a branch of the Paleo-Tethys Ocean. The Zhongdian arc, located in the south of the Yidun island arc, has relatively large number of porphyry [...] Read more.

The Yidun island arc was formed in response to the Late Triassic westward subduction of the Ganzi–Litang oceanic plate, a branch of the Paleo-Tethys Ocean. The Zhongdian arc, located in the south of the Yidun island arc, has relatively large number of porphyry (skarn) type Cu–Mo ± Au polymetallic deposits, the largest of which is the Pulang Cu (–Mo–Au) deposit with proven Cu reserves of 5.11 Mt, Au reserves of 113 t, and 0.17 Mt of molybdenum. However, the relationship between mineralization and the potassic alteration zone, phyllic zone, and propylitic zone of the Pulang porphyry deposit is still controversial and needs further study. Titanite (CaTiSiO₅) is a common accessory mineral in acidic, intermediate, and alkaline igneous rocks. It is widely developed in various types of metamorphic rocks, hydrothermally altered rocks, and a few sedimentary rocks. It is a dominant Mo-bearing phase in igneous rocks and contains abundant rare earth elements and high-field-strength elements. As an effective geochronometer, thermobarometer, oxybarometer, and metallogenic potential indicator mineral, titanite is ideal to reveal the magmatic–hydrothermal evolution and the mechanism of metal enrichment and precipitation. In this paper, major and trace element contents of the titanite grains from different alteration zones were obtained using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to define the changes in physicochemical conditions and the behavior of these elements during the process of hydrothermal alteration at Pulang. Titanite in the potassic alteration zone is usually shaped like an envelope. It occurs discretely or is enclosed by feldspar, with lower contents of CaO, Al, Sr, Zr and Hf; a low Nb/Ta ratio; high ∑REE + Y, U, Th, Ta, Nb, and Ga content; and high FeO/Al₂O₃ and LREE/HREE ratios. This is consistent with the characteristics of magmatic titanite from fresh quartz monzonite porphyry in Pulang and other porphyry Cu deposits. Titanite in the potassium silicate alteration zone has more negative Eu anomaly and a higher U content and Th/U ratio, indicating that the oxygen fugacity decreased during the transformation to phyllic alteration and propylitic alteration in Pulang. High oxygen fugacity is favorable for the enrichment of copper, gold, and other metallogenic elements. Therefore, the enrichment of copper is more closely related to the potassium silicate alteration. The molybdenum content of titanite in the potassium silicate alteration zone is 10²–10⁴ times that of the phyllic alteration zone and propylitic alteration zone, while the copper content is indistinctive, indicating that molybdenum was dissolved into the fluid or deposited in the form of sulfide before the medium- to low-temperature hydrothermal alteration, which may lead to the further separation and deposition of copper and molybdenum. Full article

(This article belongs to the Special Issue Thermal History and Preservation Mechanisms of Porphyry-Cu Deposits: Evidence from Thermochronology, Mineral and Isotopic Geochemistry)

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15 pages, 15358 KiB

Open AccessEditor’s ChoiceArticle

Comparative Study of Colloidal and Rheological Behaviors of Mixed Palygorskite–Montmorillonite Clays in Freshwater and Seawater

by Jiajun Zhang, Guanzheng Zhuang, Jinrong Chen, Wenxiao Fan, Jixing Fan, Zhuhua Kuang and Dong Liu

Minerals 2025, 15(3), 251; https://doi.org/10.3390/min15030251 - 28 Feb 2025

Viewed by 654

Abstract

This study systematically investigates the colloidal stability, rheological properties, and filtration behavior of palygorskite–montmorillonite mixed clays in both freshwater and seawater systems. By varying the mass content and dispersion medium (freshwater/seawater), we analyze the colloidal stability, zeta potential, flow curves, viscosity, shear-thinning behavior, [...] Read more.

This study systematically investigates the colloidal stability, rheological properties, and filtration behavior of palygorskite–montmorillonite mixed clays in both freshwater and seawater systems. By varying the mass content and dispersion medium (freshwater/seawater), we analyze the colloidal stability, zeta potential, flow curves, viscosity, shear-thinning behavior, thixotropy, and fluid loss of the dispersions. The results show that palygorskite exhibits good rheological performance in both freshwater and seawater, while montmorillonite performs better in freshwater but suffers a significant decline in seawater. However, palygorskite demonstrates high fluid loss, which is unfavorable for drilling fluid function. Mixed clays can mitigate the limitations of individual clays to some extent, but the specific performance depends on the clay mineral content and dispersion medium. In freshwater, a small amount of montmorillonite improves the viscosity and shear-thinning behavior of the dispersion, with optimal montmorillonite contents of 22% and 38%, respectively. The thixotropy and fluid loss reduction in the mixed clays are positively correlated with montmorillonite content. In seawater, the rheological performance inversely correlates with Mt content due to montmorillonite’s high sensitivity to electrolytes. The addition of Pal enhances the colloidal stability and rheological properties of the mixed clays in seawater. This work provides theoretical insights into the behavior of mixed clays in different media, offering valuable guidance for the design of seawater-based drilling fluids. Full article

(This article belongs to the Collection Clays and Other Industrial Mineral Materials)

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51 pages, 28157 KiB

Open AccessEditor’s ChoiceArticle

Alteration Lithogeochemistry of an Archean Porphyry-Type Au(-Cu) Setting: The World-Class Côté Gold Deposit, Canada

by Laura R. Katz, Daniel J. Kontak and Benoit Dubé

Minerals 2025, 15(3), 256; https://doi.org/10.3390/min15030256 - 28 Feb 2025

Viewed by 966

Abstract

Characterizing alteration and its geochemical signature provides critical information relevant to ore-deposit genesis and its related footprint; for porphyry-type deposits, zoned potassic-phyllic-propylitic alteration and metal enrichment are critical features. Here we integrate earlier lithological and mineralogical studies of the (10+ Moz Au) Archean [...] Read more.

Characterizing alteration and its geochemical signature provides critical information relevant to ore-deposit genesis and its related footprint; for porphyry-type deposits, zoned potassic-phyllic-propylitic alteration and metal enrichment are critical features. Here we integrate earlier lithological and mineralogical studies of the (10+ Moz Au) Archean Côté Gold porphyry-type Au(-Cu) deposit (Ontario, Canada) with identified alteration types to provide exploration vectors. The ca. 2740 tonalite-quartz diorite-diorite intrusive complex and co-temporal Au(-Cu) mineralization as disseminations, breccias and veins are co-spatial with ore-related alteration types (amphibole, biotite, muscovite). An early, locally developed amphibole event coring the deposit is followed by emplacement of a Au(-Cu) mineralized biotite-rich magmatic-hydrothermal breccia body and broad halo of disseminated biotite and quartz veining. These rocks record gains via mass balance calculations of K, Fe, Mg, LILE, and LREE with Au, Cu, Mo, Ag, Se and Bi. Later muscovite alteration is enriched in K, Rb, Cs, Ba, CO₂, and LOI with varied Au, Cu, Mo, Te, As, and Bi values. A strong albite overprint records extreme Na gains with the loss of most other elements, including ore metals (i.e., Au, Cu). Together these data define an Au-Cu-Mo-Ag-Te-Bi-Se core co-spatial with biotite breccia versus a peripheral stockwork and sheeted vein zone with a Te-Se-Zn-Pb-As association. These features further support the posited porphyry-type model for the Côté Gold Au(-Cu) deposit. Full article

(This article belongs to the Special Issue New Discovery and Exploration Methods of Porphyry and Epithermal Mineral Deposits)

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23 pages, 24426 KiB

Open AccessEditor’s ChoiceArticle

Geometallurgical Characterization of the Arthur River Magnesite Deposit, Northwestern Tasmania for Pathways to Production

by Alfredtina Akua Abrafi Appiah, Julie Hunt, Mohammadbagher Fathi, Owen P. Missen, Wei Hong, Ivan Belousov, Verity Kameniar-Sandery and Mick Wilson

Minerals 2025, 15(3), 247; https://doi.org/10.3390/min15030247 - 27 Feb 2025

Cited by 1 | Viewed by 836

Abstract

The Arthur River magnesite deposit is in the northwestern part of Tasmania, Australia, within the Arthur Metamorphic Complex. Physical, mineralogical, and chemical characteristics of the deposit were studied using geological drill core logging and analytical techniques (scanning electron microscopy, portable x-ray fluorescence, and [...] Read more.

The Arthur River magnesite deposit is in the northwestern part of Tasmania, Australia, within the Arthur Metamorphic Complex. Physical, mineralogical, and chemical characteristics of the deposit were studied using geological drill core logging and analytical techniques (scanning electron microscopy, portable x-ray fluorescence, and laser ablation–inductively coupled plasma–mass spectrometry). The results document variations within the ore body, and three ore types have been identified for the potential production of an economic magnesite concentrate separated from associated gangue minerals (dolomite, quartz, and talc and iron bearing minerals such as pyrite and pyrrhotite). The ore types were identified based on a combination of physical, chemical, and mineralogical differences. Type 1 has a relatively high magnesium content and appears in drill core as hard white crystalline magnesite. Type 2 has relatively lower magnesium and higher iron contents than type 1 and occurs visibly as creamy-yellowish soft magnesite. Type 3 ore has the lowest magnesium and the highest iron content of the three ore types and is reddish brown in color. From the characterization studies, potential beneficiation routes for each ore type are suggested along with potential processing challenges. Examples of processing challenges include magnesium present in both magnesite and in dolomite, and the association of magnesite with quartz and talc results in a relatively high silica content. Full article

(This article belongs to the Special Issue Microanalysis Applied to Mineral Deposits)

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24 pages, 4725 KiB

Open AccessEditor’s ChoiceArticle

Unlocking Subsurface Geology: A Case Study with Measure-While-Drilling Data and Machine Learning

by Daniel Goldstein, Chris Aldrich, Quanxi Shao and Louisa O’Connor

Minerals 2025, 15(3), 241; https://doi.org/10.3390/min15030241 - 26 Feb 2025

Cited by 2 | Viewed by 1300

Abstract

Bench-scale geological modeling is often uncertain due to limited exploration drilling and geophysical wireline measurements, reducing production efficiency. Measure-While-Drilling (MWD) systems collect drilling data to analyze mining blast hole drill rig performance. Early MWD studies focused on penetration rates to identify rock types. [...] Read more.

Bench-scale geological modeling is often uncertain due to limited exploration drilling and geophysical wireline measurements, reducing production efficiency. Measure-While-Drilling (MWD) systems collect drilling data to analyze mining blast hole drill rig performance. Early MWD studies focused on penetration rates to identify rock types. This paper investigates Artificial Intelligence (AI)-based regression models to predict geophysical signatures like density, gamma, magnetic susceptibility, resistivity, and hole diameter using MWD data. The machine learning (ML) models evaluated include Linear Regression (LR), Decision Trees (DTs), Support Vector Machines (SVMs), Random Forests (RFs), Gaussian Processes (GP), and Neural Networks (NNs). An analytical method was validated for accuracy, and a three-tier experimental method assessed the importance of MWD features, revealing no performance loss when excluding features with less than 2% importance. RF, DTs, and GPs outperformed other models, achieving R² values up to 0.98 with a low RMSE, while LR and SVMs showed lower accuracy. The NN’s performance improved with larger datasets. This study concludes that the DT, RF, and GP models excel in predicting geophysical signatures. While ML-based methods effectively model relationships in the data, their predictive performance remains inherently constrained by the underlying geological and physical mechanisms. Model selection depends on computational resources and application needs, offering valuable insights for real-time orebody analysis using AI. These findings could be invaluable to geologists who wish to utilize AI techniques for real-time orebody analysis and prediction. 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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21 pages, 4966 KiB

Open AccessEditor’s ChoiceArticle

Influence of Particle Shape and Size on Gyratory Crusher Simulations Using the Discrete Element Method

by Manuel Moncada, Christian Rojas, Patricio Toledo, Cristian G. Rodríguez and Fernando Betancourt

Minerals 2025, 15(3), 232; https://doi.org/10.3390/min15030232 - 26 Feb 2025

Cited by 1 | Viewed by 857

Abstract

Gyratory crushers are fundamental machines in aggregate production and mineral processing. Discrete Element Method (DEM) simulations offer detailed insights into the performance of these machines and serve as a powerful tool for their design and analysis. However, these simulations are computationally intensive due [...] Read more.

Gyratory crushers are fundamental machines in aggregate production and mineral processing. Discrete Element Method (DEM) simulations offer detailed insights into the performance of these machines and serve as a powerful tool for their design and analysis. However, these simulations are computationally intensive due to the large number of particles involved and the need to account for particle breakage. This study aims to investigate the effect of particle shape and size distribution on the performance of a DEM model of a gyratory crusher. The selected study case corresponds to a primary gyratory crusher operating in a copper processing industry. As particle shapes, spheres and polyhedrons are used with a particle replacement scheme. This study utilizes two different size distributions, with variations also applied to the minimum particle size. The results are analyzed in terms of the impact of these factors on the power draw, mass flow, and product size distribution for each of the combinations explained. The findings demonstrate that particle shape primarily influences the product size distribution, whereas variations in particle size distribution have a pronounced effect on power draw, mass flow rate, and product size distribution. Based on the results, recommendations are provided regarding the selection of the minimum particle size. It is concluded that the minimum particle size should not exceed a third of the closed-side setting to ensure accurate and reliable simulation outcomes. Full article

(This article belongs to the Special Issue Process Modelling and Applications for Aggregate Production)

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20 pages, 5571 KiB

Open AccessEditor’s ChoiceArticle

Utilization of the Finer Particle Fraction of Arsenic-Bearing Excavated Rock Mixed with Iron-Based Adsorbent as Sorption Layer

by Daisuke Ishigami, Takahiko Arima, Satoshi Shinohara, Yutaka Kamijima, Keijirou Ito, Tasuma Suzuki, Keita Nakajima, Walubita Mufalo and Toshifumi Igarashi

Minerals 2025, 15(3), 242; https://doi.org/10.3390/min15030242 - 26 Feb 2025

Viewed by 1524

Abstract

Excavated rocks generated during tunnel construction may pose an environmental hazard due to the release of acidic leachate containing potentially toxic elements (PTEs). Addressing this concern requires strategic countermeasures against mitigating the release of PTEs. This study investigated the efficacy of a novel [...] Read more.

Excavated rocks generated during tunnel construction may pose an environmental hazard due to the release of acidic leachate containing potentially toxic elements (PTEs). Addressing this concern requires strategic countermeasures against mitigating the release of PTEs. This study investigated the efficacy of a novel approach for managing altered excavated rocks that generate acidic leachates with elevated arsenic (As) by utilizing the finer altered rock as a base material for the sorption layer. The proposed method involves classifying the altered excavated rocks into coarse (9.5–37.5 mm) and finer (<9.5 mm) fractions, with the finer fractions incorporated with iron (Fe)-based adsorbent to form a bottom sorption layer for the disposal of coarser rock samples. Leaching behavior and As immobilization efficiency were assessed through shaking, stirring leaching tests, batch sorption tests, and column tests under varying particle size fractions of the rock samples. Results indicate that altered finer rock fractions exhibit increased As leaching under shaking conditions due to enhanced dissolution. The addition of >1% of Fe-based adsorbent to the finer rock in the sorption layer effectively suppressed As leaching concentration, meeting the management criterion of <0.3 mg/L for specially controlled contaminated soils in Japan. Batch sorption tests using the finer rock samples with the Fe-based adsorbent confirmed their efficacy as effective adsorbents. This efficacy was further elucidated in column experiments consisting of the coarse rock samples and fine altered rock samples mixed with the Fe based adsorbent at the bottom as a sorption layer. Results showed that the sorption layer effectively decreased the As leached from the rock layer, utilizing the altered excavated fine rock as a base material in the sorption layer. This approach highlights the potential for repurposing excavated rocks as sorption media, enabling sustainable management strategies for As-contaminated rocks. This study provides an innovative framework for integrating adsorption-based remediation, contributing to sustainable countermeasure strategies for excavated rocks. Full article

(This article belongs to the Special Issue Environmental Geochemistry of Heavy Metals: Contamination, Impacts, and Countermeasure Strategies)

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23 pages, 8147 KiB

Open AccessEditor’s ChoiceArticle

Thermochronology of the Kalba–Narym Batholith and the Irtysh Shear Zone (Altai Accretion–Collision System): Geodynamic Implications

by Alexey Travin, Mikhail Buslov, Nikolay Murzintsev, Valeriy Korobkin, Pavel Kotler, Sergey V. Khromykh and Viktor D. Zindobriy

Minerals 2025, 15(3), 243; https://doi.org/10.3390/min15030243 - 26 Feb 2025

Viewed by 558

Abstract

The granitoids of the Kalba–Narym batholith and the Irtysh shear zone (ISZ) are among the main geological features of the late Paleozoic Altai accretion–collision system (AACS) in Eastern Kazakhstan. Traditionally, it is believed that late Paleozoic strike-slip faults played a pivotal role at [...] Read more.

The granitoids of the Kalba–Narym batholith and the Irtysh shear zone (ISZ) are among the main geological features of the late Paleozoic Altai accretion–collision system (AACS) in Eastern Kazakhstan. Traditionally, it is believed that late Paleozoic strike-slip faults played a pivotal role at all stages of the development of the AACS, they were supposed to control deformation, magmatism, and ore deposits. This work is devoted to solving the problem of the tectonic evolution of the AACS based on the reconstruction of the thermal history of granitoids of the Kalba–Narym batholith in connection with the Chechek metamorphic dome structure, which is one of the highly metamorphosed blocks mapped within the ISZ. The new geological and geochronological data presented in this work allowed us to establish the sequence of formation of the Kalba–Narym granitoid batholith and link it with the evolution of the Irtysh shear zone (ISZ). It was revealed that in the late Carboniferous–early Permian (312–289 Ma), during the NE–SW compression, the Irtysh shear zone formed as a gently dipping thrust system into which gabbro of the Surov massif intruded. The combined manifestation of magmatic and tectonic processes caused the formation of tectonic mélange with cataclastic gabbro and metamorphic rocks of the Chechek metamorphic dome structure (312–289 Ma). Compression caused the formation of a cover-thrust structure. The thickening of the crust under the probable thermal action of the Tarim plume led to the formation of the early Permian Kalba–Narym batholith (297–284 Ma) within the Kalba–Narym terrane. Denudation of the orogen occurred before the Early Triassic (280–229 Ma). In this way the sequence of formation of the Kalba–Narym batholith and the ISZ is consistent with the concepts of the stages of plume-lithosphere interaction within the AACS under the influence of the late Carboniferous–early Permian Tarim igneous province, but in the cover-thrust tectonic setting. Full article

(This article belongs to the Special Issue Developments in Geochronology and Dating of Shear Zone Deformation)

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20 pages, 5757 KiB

Open AccessEditor’s ChoiceArticle

Mineral Chemistry of Li-Bearing Minerals at the Giant Tanco Pegmatite, Canada

by Paul Alexandre and Stefano Salvi

Minerals 2025, 15(3), 221; https://doi.org/10.3390/min15030221 - 24 Feb 2025

Cited by 1 | Viewed by 829

Abstract

The highly fractionated late Archean Tanco pegmatite (Bernic Lake, SE Manitoba, Canada) is a world-class producer of tantalum and cerium but is also a major source of lithium. In order to better understand the major Li hosts and the overall Li budget of [...] Read more.

The highly fractionated late Archean Tanco pegmatite (Bernic Lake, SE Manitoba, Canada) is a world-class producer of tantalum and cerium but is also a major source of lithium. In order to better understand the major Li hosts and the overall Li budget of the Tanco pegmatite, the lithium-bearing minerals present here were analyzed for major and trace elements by electron microprobe and laser ablation ICP-MS, respectively. The major Li-bearing minerals present in the Tanco pegmatite are eucryptite (approximately 11.0 wt% Li₂O), montebrasite (~11.2 wt%), lithiophilite (9.1 wt%), spodumene (~8.8 wt%), petalite (5.45 wt%), lepidolite (4.36 wt%), and tancoite (5.2 wt%); Li is also present in lithiowodginite, tourmaline, muscovite, beryl, pollucite, and apatite (between 0.1 and 1.3 wt% Li₂O). Most of the Li present in Tanco is contained in petalite (69.4% of all the Li present here), followed by spodumene (11.4%), montebrasite (11.1%), and eucryptite (4.0%); all remaining Li-bearing minerals contain 4.0% of the Li present in the Tanco pegmatite. Overall, the Tanco pegmatite contains approximately 0.71 wt% Li₂O, on par with previous estimates. The major practical implications of these finding are that (1) all Li-bearing minerals have to be considered to properly estimate the Li endowment of any pegmatite; (2) the main Li-bearing mineral is not always spodumene; (3) the exact and detailed Li mineralogy of a pegmatite will directly affect extraction and processing; and (4) a significant proportion of Li in any pegmatite is contained in other minerals than the main one, be it spodumene of petalite. Full article

(This article belongs to the Section Mineral Deposits)

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