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Minerals, Volume 13, Issue 8 (August 2023) – 122 articles

Cover Story (view full-size image): A regional-scale Cenozoic-era marine unconformity surface, which was uplifted to 1600 m in New Zealand. The photograph was taken by Susan Vearncombe. Placer gold is absent, but nearby, older and younger non-marine placers are confined to narrow incised fluvial channels. Similar marine unconformities formed offshore during the Pleistocene and Holocene eras. These marine unconformities resemble those identified in the Archean Witwatersrand goldfield, South Africa, in terms of regional extent and planarity. Witwatersrand gold may have been post-depositionally placed at these unconformities. View this paper
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18 pages, 2570 KiB  
Article
Effect of Temperature and Water Salinity on Electrical Surface Conduction of Clay Particles
by Md Farhad Hasan and Hossam Abuel-Naga
Minerals 2023, 13(8), 1110; https://doi.org/10.3390/min13081110 - 21 Aug 2023
Cited by 4 | Viewed by 1388
Abstract
In this study, the combined effect of temperature (T) and pore water salinity on electrical surface conduction parameters was investigated. Two new electrical surface conduction parameters, namely, electrical conductivity of effective solid (σs) and size of diffuse double layer (DDL) water [...] Read more.
In this study, the combined effect of temperature (T) and pore water salinity on electrical surface conduction parameters was investigated. Two new electrical surface conduction parameters, namely, electrical conductivity of effective solid (σs) and size of diffuse double layer (DDL) water per unit volume of soil (χ), were considered in this study. The tested samples included two commercially available clays and four natural clay soils with diverse physico-chemical properties. The two surface conduction parameters were also used to assess the influence of temperature (T) and pore water salinity, as well as the electrical conductivity of free water (σFW), on the evolution of the free swelling index (FSI) of clays/clay soils through experimental methods. The findings suggested that elevated temperature and σFW increased σs but reduced χ, as well as the FSI of clays/clay soils. Furthermore, the rate of reduction for both χ and FSI augmented under the influence of increased free water salinity, particularly for clays/clay soils with high swelling capacity. The combined reductions of χ and FSI provided substantial evidence that clay DDL thickness decreases as T and σFW increase concurrently. Full article
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15 pages, 2129 KiB  
Article
Zn(NH3)2Cl2, a Mineral-like Anthropogenic Phase with Ammine Complexes from the Burned Dumps of the Chelyabinsk Coal Basin, South Urals, Russia: Crystal Structure, Spectroscopy and Thermal Evolution
by Andrey A. Zolotarev, Margarita S. Avdontceva, Rezeda M. Sheveleva, Igor V. Pekov, Natalia S. Vlasenko, Vladimir N. Bocharov, Maria G. Krzhizhanovskaya, Anatoly A. Zolotarev, Mikhail A. Rassomakhin and Sergey V. Krivovichev
Minerals 2023, 13(8), 1109; https://doi.org/10.3390/min13081109 - 21 Aug 2023
Cited by 1 | Viewed by 1114
Abstract
The mineral-like anthropogenic phase Zn(NH3)2Cl2, with ammine (NH30) complexes from the burned dumps of the Chelyabinsk coal basin (South Urals, Russia), has been investigated using single-crystal and high-temperature powder X-ray diffraction, and Raman and [...] Read more.
The mineral-like anthropogenic phase Zn(NH3)2Cl2, with ammine (NH30) complexes from the burned dumps of the Chelyabinsk coal basin (South Urals, Russia), has been investigated using single-crystal and high-temperature powder X-ray diffraction, and Raman and infrared (IR) spectroscopy. The anthropogenic Zn(NH3)2Cl2 is orthorhombic, Imma, a = 7.7399(6), b = 8.0551(5), c = 8.4767(8) Å, V = 528.49(7) Å3, R1 = 0.0388 at −73 °C. Its crystal structure is based upon isolated ZnN2Cl2 tetrahedra connected by hydrogen bonds (between NH3 groups and Cl atoms) into a three-dimensional network. Upon heating, the Zn(NH3)2Cl2 phase is stable up to about 150 °C, which is in good agreement with the data on the temperature of its formation. The crystal structure of Zn(NH3)Cl2 expands anisotropically with the strongest thermal expansion observed along the a axis. The thermal expansion of the structure is controlled by the changes in the hydrogen bonding system. The Raman and IR spectroscopic characteristics of this phase are close to those of the mineral ammineite, CuCl2(NH3)2. The studied anthropogenic phase, formed in the unique conditions of burned coal dumps, is identical to the synthetic Zn(NH3)2Cl2. Full article
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15 pages, 9130 KiB  
Article
The ESR Signals in Different Minerals and the Bleaching of Feldspar
by Weili Bi, Chaolu Yi, Haijun Yang, Xiangke Xu and Gang Hu
Minerals 2023, 13(8), 1108; https://doi.org/10.3390/min13081108 - 21 Aug 2023
Viewed by 889
Abstract
The use of quartz is critical to the electron spin resonance (ESR) dating of sediments and fault gouges. The germanium center (Ge center) in quartz is a commonly used color center employed in ESR signal measurement. Although Ge center signals in quartz can [...] Read more.
The use of quartz is critical to the electron spin resonance (ESR) dating of sediments and fault gouges. The germanium center (Ge center) in quartz is a commonly used color center employed in ESR signal measurement. Although Ge center signals in quartz can be detected using an ESR spectrometer, they are weak and sometimes undetectable. Impurities in quartz grains can further aggravate these deficiencies and may even invalidate any attempt to repeat ESR ages due to the deficiencies evident in the processes used in sample preparation. Using sieving, carbonate-organic matter removal, water flotation, magnetic separation, heavy liquid separation, and HF solution etching, we separated quartz, feldspar (plagioclase), mica, and the heavy minerals and measured the ESR signal in each of them to examine the impact of impurities within mineral grains on the ESR signals. From the ESR spectra, we observed intense ESR signals in feldspar and the heavy minerals and weak signals in mica at the same positions as the Ge center in the quartz. The ESR signals in the feldspar proved to be the most intense and overrode the peaks exhibited by the Ge center in the quartz. Feldspar is commonly associated with quartz in sediments, but it is difficult to separate it from quartz as their colors, specific gravities, and magnetic properties are similar. Any ESR signal in quartz containing foreign minerals would therefore be likely to be heavily disturbed by the signals from these foreign minerals, particularly from the feldspar and heavy minerals. ESR signals in the feldspar decreased similarly to those in the quartz when exposed to sunlight, declining by 70%–80% after being exposed for 50 h. Such declination was more obvious in high-altitude areas than in low-altitude areas. Our results indicate that highly pure quartz is required when dating; we would therefore strongly suggest that the procedures for the purification of quartz grains should include floating, heavy liquid separation, and HF solution etching to remove the feldspar, heavy minerals, and any remnant magnetite. Such a procedure would guarantee that the signal that is measured comes from the quartz alone, allowing repeatable measurements using the same spectrometer as well as valid comparisons between the spectrometries derived from different spectrometers. Full article
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14 pages, 44596 KiB  
Article
Temporal–Spatial Distributions and Influencing Factors of Heavy Metals As, Cd, Pb, and Zn in Alluvial Soils on a Regional Scale in Guangxi, China
by Mi Tian, Xueqiu Wang, Jian Zhou, Qinghua Chi, Dongsheng Liu, Yu Qiao, Chao Wu, Yining Zhou, Qiang Wang and Futian Liu
Minerals 2023, 13(8), 1107; https://doi.org/10.3390/min13081107 - 21 Aug 2023
Cited by 1 | Viewed by 1398
Abstract
Understanding the temporal–spatial distribution and influencing factors of heavy metals on a regional scale is crucial for assessing the anthropogenic impacts and natural variations in elemental geochemical behavior. This study evaluated the spatial distributions of the heavy metals As, Cd, Pb, and Zn [...] Read more.
Understanding the temporal–spatial distribution and influencing factors of heavy metals on a regional scale is crucial for assessing the anthropogenic impacts and natural variations in elemental geochemical behavior. This study evaluated the spatial distributions of the heavy metals As, Cd, Pb, and Zn as well as the driving mechanisms over the past 31 years in Guangxi, China, using three geochemical baseline projects (the Environmental Geochemical Monitoring Network Project (EGMON) project 1992–1996; the Geochemical Baseline (CGB) 1 project 2008–2012; and the CGB2 project 2015–2019). By calculating the variable importance using the random forest algorithm, it was found that natural factors are the primary drivers of the spatial distribution of heavy metals in the EGMON project, especially precipitation for As, the digital elevation model (DEM) for Cd and Pb, and temperature for Zn. Surface alluvial soils showed obvious heavy metal enrichment in the CGB1 project, with the gross domestic product (GDP) driving the spatial distribution of all heavy metals. In addition, the anomalous intensity and range of heavy metals in the CGB2 project decreased significantly compared with the CGB1 project, especially owing to the normalized difference vegetation index (NDVI) as a positive anthropogenic factor that improves the degree of rocky desertification, thus reducing the heavy metal contents of As and Pb, and the precipitation promoting the decomposition of Fe–Mn concretions and thus the migration of Cd and Zn. This research promotes an understanding of anthropogenic and natural influences on the spatiotemporal distribution of heavy metals and is of great significance for environmental monitoring and governance. Full article
(This article belongs to the Special Issue Geochemical Characteristics and Contamination Risk Assessment of Soil)
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16 pages, 13604 KiB  
Article
Ancient Metasomatism in the Lithospheric Mantle, Eastern North China Craton: Insights from In-Situ Major and Trace Elements in Garnet Xenocrysts, Mengyin District
by Hao-Shuai Wang, Li-Qiang Yang, Zhi-Yuan Chu, Liang Zhang, Nan Li, Wen-Yan He, Ya-Nan Zhang and Yi-Qi Wang
Minerals 2023, 13(8), 1106; https://doi.org/10.3390/min13081106 - 20 Aug 2023
Cited by 1 | Viewed by 1252
Abstract
Mantle metasomatism refers to the interaction between mantle melt, fluid, and mantle rock. It not only affects the physical and chemical properties of the lithospheric mantle but also plays an important role in the process of metal and gem mineralization. In order to [...] Read more.
Mantle metasomatism refers to the interaction between mantle melt, fluid, and mantle rock. It not only affects the physical and chemical properties of the lithospheric mantle but also plays an important role in the process of metal and gem mineralization. In order to explore the nature and evolution of metasomatism in the lithospheric mantle of the Mengyin area in the eastern part of the North China Craton, this paper combines the previous data of garnet inclusions in diamonds and analyzes the major and trace elements of garnet xenocrysts in the Shengli No. 1 kimberlite pipe from the EPMA and LA-ICP-MS experiments. The experiments show that the garnet xenocrysts of the Shengli No. 1 kimberlite pipe are mainly lherzolitic and harzburgitic garnets. The content of Zr and TiO2 in some garnets are low, which are the characteristics of depleted garnets. Conversely, another group of garnets display high Zr and TiO2 contents, indicative of high-temperature melt metasomatism. When comparing the Ti/Eu ratio of the depleted garnets to that of the primary mantle, a significantly lower value is observed. Additionally, the (Sm/Er)N value undergoes minimal changes, while the Zr/Hf value exceeds that of the primary mantle. These characteristics are indicators of carbonatite melt metasomatism. Garnets that are affected by high-temperature melt metasomatism exhibit low (Sm/Er)N content, a significant variation in the Ti/Eu ratio, and a Zr/Hf value greater than that of the primary mantle. These characteristics indicate the influence of kimberlite melt metasomatism. Garnets impacted by carbonatite melt metasomatism display a strong sinusoidal distribution pattern of rare earth elements (REE) and are often found as lherzolitic garnet xenocrysts and garnet inclusions in diamond. On the other hand, garnets influenced by kimberlite melt metasomatism exhibit a slight sinusoidal REE distribution pattern in harzburgitic garnets and a slight sinusoidal REE distribution or a flat pattern from medium rare earth elements (MREEs) to heavy rare earth elements (HREEs) in lherzolitic garnet xenocrysts. Based on these findings, it is evident that there are at least two types of metasomatism occurring in the lithospheric mantle of the Mengyin area in the eastern part of the North China Craton. The first type involves the metasomatism of early carbonatite melt to the mantle peridotite. Garnets formed under this condition exhibit high Sr and LREE contents, as well as low Zr, Hf, Ti, Y, and HREE contents, indicating depletion characteristics. The second type entails the metasomatism of late kimberlite melts affecting the mantle peridotite. Garnets formed under this process display high Zr, Hf, Ti, Y, and HREE contents. Full article
(This article belongs to the Section Mineral Deposits)
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20 pages, 7976 KiB  
Article
Study on Mechanical and Flow Properties of Cemented Sulfur Tailings Backfill Considering the Influence of Fiber Type, Fiber Content and Addition Method
by Wei Liu, Shenghua Yin, Yongqiang Hou and Minzhe Zhang
Minerals 2023, 13(8), 1105; https://doi.org/10.3390/min13081105 - 20 Aug 2023
Cited by 1 | Viewed by 794
Abstract
Previous studies have confirmed that for cemented tailings backfill, mechanical properties are improved through the addition of fiber. However, for fiber-reinforced cemented sulfur tailings backfill (FRCSTB), physical and flow properties are still unknown. In this paper, the changes in fluidity, splitting tensile strength [...] Read more.
Previous studies have confirmed that for cemented tailings backfill, mechanical properties are improved through the addition of fiber. However, for fiber-reinforced cemented sulfur tailings backfill (FRCSTB), physical and flow properties are still unknown. In this paper, the changes in fluidity, splitting tensile strength (STS) and uniaxial compressive strength (UCS) of cemented sulfur tailings backfill (CSTB) are analyzed in detail. Secondly, regarding the addition of glass fiber and polypropylene fiber, the changes in the fluidity, STS and UCS of the CSTB, resulting from the fiber length, fiber content and method of fiber addition used, were analyzed. Moreover, the relationship between the UCS and fiber content is established. Finally, the mechanism behind the influence of fiber and sulfur content on the mechanical properties of CSTB is revealed. The results indicate that with the increase in sulfur content, the fluidity of the tailings slurry exhibits exponential growth. During the process of increasing sulfur content, the UCS and STS of CSTB initially increase and then decrease, reaching maximum values at 12% sulfur content. Similarly, at a fiber content of 0.6%, the UCS and 28d STS of CSTB reach their maximum values. In terms of enhancing the mechanical properties of CSTB, the effectiveness of glass fibers surpasses that of polypropylene fibers. In addition, regarding the improvement of the UCS of CSTB, the mixed addition of fibers is obviously worse than that of fiber alone. However, in terms of enhancing the STS of CSTB, the mixed addition of fibers outperforms the single addition of polypropylene fiber. From a microscopic perspective, polypropylene and glass fiber are able to form strong cohesion with the cement–tailings matrix and effectively prevent the formation and expansion of pores and cracks. Full article
(This article belongs to the Special Issue Cemented Mine Waste Backfill: Experiment and Modelling)
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21 pages, 5577 KiB  
Article
A Comparative Study of Malonic and l-Glutamic Acids for Metal Leaching from Spent Lithium-Ion Batteries: Kinetic and Optimization Analysis
by Laleh Sohbatzadeh, Sied Ziaedin Shafaei Tonkaboni, Mohammad Noaparast and Ali Entezari-Zarandi
Minerals 2023, 13(8), 1104; https://doi.org/10.3390/min13081104 - 19 Aug 2023
Viewed by 869
Abstract
In this research, two different hydrometallurgical processes were introduced for recycling the cathodes of lithium-ion batteries (LIBs) from spent LIBs. The cathode materials were leached by malonic acid (MOA), as a leaching agent, and ascorbic acid (AA), as a reducing agent, in the [...] Read more.
In this research, two different hydrometallurgical processes were introduced for recycling the cathodes of lithium-ion batteries (LIBs) from spent LIBs. The cathode materials were leached by malonic acid (MOA), as a leaching agent, and ascorbic acid (AA), as a reducing agent, in the first process, and by l-Glutamic acid (l-Glu), as a leaching agent, and AA, as a reducing agent, in the second process. The results of the tests showed that, with a similar solid-to-liquid (S/L) ratio of 10 g/L and a recovery time of 2 h for both processes, when using MOA of 0.25 M and AA of 0.03 M at 88 °C, 100% lithium (Li), 80% cobalt (Co), 99% nickel (Ni), and 98% manganese (Mn) were extracted, and when using l-Glu of 0.39 M and AA of 0.04 M at 90 °C, 100% Li, 79% Co, 91% Ni, and 92% Mn were extracted. The kinetics of the leaching process for the two systems were well justified by the Avrami equation, which was diffusion-controlled in the MOA + AA system, with the apparent activation energy of 3.23, 14.72, 7.77, and 7.36 kJ/mol for Mn, Ni, Co, and Li, respectively. The l-Glu + AA involved chemical-diffusion kinetic control, with the apparent activation energy for Mn, Ni, Co, and Li of 9.95, 29.42, 20.15, and 16.08 kJ/mol, respectively. Various characterization techniques were used to explain the observed synergistic effect in the l-Glu + AA system, which resulted in reduced acid consumption and enhanced recovery compared to the case of MOA + AA. This occurred because l-Glu is not able to reduce and recover metals without a reductant, while MOA has reductant properties. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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13 pages, 14361 KiB  
Article
Investigating the Formation of Hot-Dry Rock in Gonghe Basin, Qinghai, China
by Yang Yang, Fangbo Chen, Siliu Yu, Yubin Zheng, Sujie He, Yan Zeng, Xiaoli Xie, Jie Zhu and Nan Luo
Minerals 2023, 13(8), 1103; https://doi.org/10.3390/min13081103 - 19 Aug 2023
Viewed by 1035
Abstract
The Gonghe Basin, Qinghai Province, China, has rich geothermal and hot-dry rock resources. Through a magnetotelluric survey line with 400 points, combined with regional geology data, the deep geoelectrical structural background and thermal source mechanisms of the Gonghe Basin were explored. The results [...] Read more.
The Gonghe Basin, Qinghai Province, China, has rich geothermal and hot-dry rock resources. Through a magnetotelluric survey line with 400 points, combined with regional geology data, the deep geoelectrical structural background and thermal source mechanisms of the Gonghe Basin were explored. The results showed that (1) a deep structure with high conductivity may exist at a depth of 15 km in the basin, and could be compared to the layer-shaped, low-velocity, high-conductivity structure in the eastern part of the Qinghai–Tibet Plateau; (2) the rushing reverse fault played a crucial role in heat control and conduction from the hot field; and (3) high-temperature heat storage existed, including four layers of geothermal resources. This study proposed a triple-polymorphism model of hot-dry rock in the area; that is, the high-conductivity layer in the Middle–Late Cenozoic crust was the principal heat source; the Middle–Late Triassic granite was the essential heat-storing body, as well as a parent rock to the hot-dry rock; and the Cenozoic sedimentary rock was the effective caprock. This model is critical to understanding geothermal causes, predicting geothermal resources, and planning, on the Qinghai–Tibet Plateau. Full article
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20 pages, 11995 KiB  
Article
Pore Structure Characteristics and Main Control Factors of Sandstone in the Jurassic Zhiluo Formation in the Northern Ordos Basin
by Xiaofeng Liu, Xiaodan Guo, Zenglin Hong, Xuping Xue and Shifeng Li
Minerals 2023, 13(8), 1102; https://doi.org/10.3390/min13081102 - 18 Aug 2023
Viewed by 704
Abstract
The Jurassic Yan’an Formation in the Ordos Basin is one of the main coal seams mined in the basin, and the enrichment of water bodies in the upper part of this coal seam is closely related to the sand bodies in the Zhiluo [...] Read more.
The Jurassic Yan’an Formation in the Ordos Basin is one of the main coal seams mined in the basin, and the enrichment of water bodies in the upper part of this coal seam is closely related to the sand bodies in the Zhiluo Formation. This study is based on the use of core observations in the northern part of the Ordos Basin for studying the pore characteristics of the permeable sand layer of the Zhiluo Formation in the study area through testing methods such as ordinary thin sections, cast thin sections, scanning electron microscopy (SEM), mercury intrusions, and physical property analysis. The results indicate that the primary pores of the Zhiluo Formation sandstone in the study area include primary intergranular pores, residual intergranular pores, and interstitial micropores. The secondary pores are mainly intergranular pores, feldspar dissolution pores, and rock debris dissolution pores. The throat-type pores are mainly variable fault contractions, sheets, curved sheets, and bundle-shaped throats. The pore structures of the Zhiluo Formation sandstone in the research area are complex, and the permeability is influenced by the throat characteristics. The main controlling factors of the pore structure characteristics of the Zhiluo Formation sandstone in the study area are sedimentation and diagenesis. Compaction and cementation are the main factors that destroy the sandstone pore structure, while later dissolution plays a certain role in the improvement of the pores. Section 1 of the Zhiluo Formation is greatly affected by diagenesis, and section 2 is greatly affected by sedimentation. Full article
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17 pages, 9925 KiB  
Article
Evaluation Model of Hard Limestone Reformation and Strength Weakening Based on Acidic Effect
by Mingxiao Hou, Bingxiang Huang, Xinglong Zhao, Xuejie Jiao, Xufei Jiang and Zheng Sun
Minerals 2023, 13(8), 1101; https://doi.org/10.3390/min13081101 - 18 Aug 2023
Viewed by 911
Abstract
The typical thick-hard limestone roof with high failure pressure and easy fracture closure under in situ stress is extremely prone to induce disasters, which seriously threatens the safe production of coal mines. The modification of carbonate minerals by acidic effects can effectively realize [...] Read more.
The typical thick-hard limestone roof with high failure pressure and easy fracture closure under in situ stress is extremely prone to induce disasters, which seriously threatens the safe production of coal mines. The modification of carbonate minerals by acidic effects can effectively realize the weakening control of hard limestone strata. In this study, a multi-factor orthogonal experiment was designed for limestone acidification reactions, and the evaluation model for the reformation and strength weakening of hard limestone based on the acidic effect was established accordingly. The results showed that there is an order in the influence of various factors on the reaction parameters and strength indices of acidified limestone, and the improvement of rock properties by the level difference of acid concentration is significantly better than that of acid type and acidification time. Through numerical analysis, the evaluation model of limestone reformation and strength weakening considering the acid reaction parameters is given. The reliability of the model passed the credibility test and experimental verification, which can effectively reflect the strength response characteristics of acidified limestone. The simulated annealing (SA) algorithm is introduced to derive the optimal acidification system suitable for limestone weakening. Combined with the model, the control mechanism of the acidic effect on hard limestone strata was analyzed. The acidic effect can not only induce the rapid generation and expansion of micro-cracks at mineral-containing crystal defects, but also make the cracks remain relatively open under in situ stress due to the differential interaction on mineral components, which is conducive to the bearing capacity reduction and structural damage of limestone rock mass. The research results provide theoretical guidance for the acidification control of hard limestone strata in underground mines. Full article
(This article belongs to the Topic Failure Characteristics of Deep Rocks, Volume II)
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15 pages, 5350 KiB  
Article
Relationship between Rock Porosity and Infrared Cooling Rate in Non-Standard Specimens of Tuffs Used in the Hungarian Cultural Heritage
by Simone Mineo, Luigi Germinario, Ákos Török and Giovanna Pappalardo
Minerals 2023, 13(8), 1100; https://doi.org/10.3390/min13081100 - 18 Aug 2023
Viewed by 783
Abstract
This paper is focused on the application of Infrared Thermography to non-standard rock specimens, in terms of size and deterioration conditions, of Hungarian tuff to monitor their cooling process and to look for a relationship between the rock Cooling Rate Index and the [...] Read more.
This paper is focused on the application of Infrared Thermography to non-standard rock specimens, in terms of size and deterioration conditions, of Hungarian tuff to monitor their cooling process and to look for a relationship between the rock Cooling Rate Index and the porosity. Literature data agree on the potential of Infrared Thermography for the indirect estimation of rock porosity in fresh specimens through the IRTest, but this technique has never been tested on non-standard specimens. To this purpose, tests on three varieties of Hungarian tuffs were carried out. These materials were selected for their cultural importance linked to their usage as building stones and in other historical applications in Northern Hungary. Tuff specimens underwent a fixed number of salt crystallization cycles. The Cooling Rate Index (CRI) for each specimen was calculated according to the literature experience and correlated to their porosity estimated by water, helium, and mercury intrusion. The results show that the rock cooling process is related to porosity since more porous rocks are characterized by faster cooling. Positive linear trends were achieved for weathered specimens considering 20 min monitoring (CRI20), which is double the time suitable for untreated rocks. The reason should be searched in salt crystallization’s effects on the rock texture, paving the way to further studies on this pioneering branch of technological application. Full article
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19 pages, 6402 KiB  
Article
Ultrafine Particle Flotation in a Concept Flotation Cell Combining Turbulent Mixing Zone and Deep Froth Fractionation with a Special Focus on the Property Vector of Particles
by Johanna Sygusch, Nora Stefenelli and Martin Rudolph
Minerals 2023, 13(8), 1099; https://doi.org/10.3390/min13081099 - 17 Aug 2023
Viewed by 1475
Abstract
Froth flotation faces increasing challenges in separating particles as those become finer and more complex, thus reducing the efficiency of the separation process. A lab flotation apparatus has been designed combining the advantages of agitator-type froth flotation for high turbulences and column flotation [...] Read more.
Froth flotation faces increasing challenges in separating particles as those become finer and more complex, thus reducing the efficiency of the separation process. A lab flotation apparatus has been designed combining the advantages of agitator-type froth flotation for high turbulences and column flotation with a deep froth zone for a fractionating effect, also enabling a study on the effect of different particle property vectors. A model system of ultrafine (<10 µm) particles was used for flotation to study how the separation process is influenced by the ultrafine property vectors of shape and wettability. To evaluate the new apparatus, flotation tests were carried out in a benchmark mechanical flotation cell under comparable conditions. Higher wettabilities result in higher recoveries, but the results show that optimum levels of hydrophobicity vary for different particle shapes. Different behaviours are observed for differently shaped particles, depending on their wettability state. The entrainment of unwanted gangue is reduced with increasing froth depth. While higher recoveries are obtained for the benchmark cell, the newly developed apparatus produces concentrates with higher grades. Our findings contribute to ultrafine flotation techniques and especially our understanding of the complex effect of particle shape in combination with the other property vectors. Full article
(This article belongs to the Special Issue Recent Advances in Flotation Process)
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15 pages, 3588 KiB  
Article
3D Multicomponent Self-Potential Inversion: Theory and Application to the Exploration of Seafloor Massive Sulfide Deposits on Mid-Ocean Ridges
by Zhongmin Zhu, Chunhui Tao, Zhigang Shan, André Revil, Zhaoyang Su, Zuofu Nie, Jinsong Shen, Xianming Deng and Jianping Zhou
Minerals 2023, 13(8), 1098; https://doi.org/10.3390/min13081098 - 17 Aug 2023
Viewed by 1092
Abstract
The marine self-potential (SP) method is currently playing an increasing role in the exploration and resource evaluation of seafloor massive sulfide (SMS) deposits. SP surveys are conducted using autonomous underwater vehicles (AUV), which yield multicomponent electric field datasets. By comparing with the single-component [...] Read more.
The marine self-potential (SP) method is currently playing an increasing role in the exploration and resource evaluation of seafloor massive sulfide (SMS) deposits. SP surveys are conducted using autonomous underwater vehicles (AUV), which yield multicomponent electric field datasets. By comparing with the single-component electrical field data used to date, the inversion of these multicomponent data is expected to provide a more accurate description of the 3D structure of SMS deposits beneath the seafloor (like gradiometry in gravity surveys). We introduce an inversion algorithm specifically adapted to multicomponent SP data. A synthetic model demonstrates that the inversion of multicomponent datasets allows us to better recover the amplitude of the current density and the morphology of the ore bodies compared to using a single component of the electrical field. Next, we apply our approach to a multicomponent SP dataset collected during the DY58 oceanic cruise at the Yuhuang hydrothermal field on the Southwest Indian Ridge. Subsequently, we reconstruct the three-dimensional (3D) geometry of the SMS deposits beneath the seafloor. The AUV-based SP system with the collection of multicomponent SP data inversion appears to be a powerful tool in the exploration and evaluation of seafloor sulfide resource and, in the future, could be used in concert with induced polarization data. Full article
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9 pages, 2514 KiB  
Article
First Terrestrial Occurrence of Kaitianite (Ti3+2Ti4+O5) from the Upper Mantle beneath Mount Carmel, Israel
by Chi Ma, Fernando Cámara, Luca Bindi, Vered Toledo and William L. Griffin
Minerals 2023, 13(8), 1097; https://doi.org/10.3390/min13081097 - 17 Aug 2023
Cited by 3 | Viewed by 1322
Abstract
Our nanomineralogical investigation of melt inclusions in corundum xenoliths from the Mount Carmel area, Israel, has revealed seven IMA-approved new minerals since 2021. We report here the first terrestrial occurrence of kaitianite (Ti3+2Ti4+O5). Kaitianite occurs as [...] Read more.
Our nanomineralogical investigation of melt inclusions in corundum xenoliths from the Mount Carmel area, Israel, has revealed seven IMA-approved new minerals since 2021. We report here the first terrestrial occurrence of kaitianite (Ti3+2Ti4+O5). Kaitianite occurs as exsolution lamellae in tistarite (Ti2O3), in a melt inclusions together with a Ti,Al,Zr-oxide, a MgTi3+2Al4SiO12 phase, spinel, sapphirine, Ti-sulfide, alabandite, and Si-rich glass in a corundum grain (Grain 1125C2). The chemical composition of kaitianite using electron probe microanalysis is (wt%) Ti2O3 58.04, TiO2 37.82, Al2O3 2.87, MgO 0.85, ZrO2 0.10, CaO 0.02, SiO2 0.02, sum 99.73, yielding an empirical formula of (Ti3+1.78Al0.12Ti4+0.05Mg0.05)(Ti4+1.00)O5, with the Ti3+ and Ti4+ partitioned, assuming a stoichiometry of three cations and five oxygen anions pfu. Electron back-scatter diffraction reveals that kaitianite has the monoclinic C2/c γ-Ti3O5-type structure with cell parameters: a = 10.12 Å, b = 5.07 Å, c = 7.18 Å, β = 112°, V = 342 Å3, and Z = 4. Kaitianite is a high-temperature oxide phase, formed in melt pockets under reduced conditions in corundum-aggregate xenoliths derived from the upper mantle beneath Mount Carmel, Israel. Full article
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26 pages, 6056 KiB  
Article
Improved Bond Strength Performance of Geopolymer Mortars: Role of High Volume Ground Blast Furnace Slag, Fly Ash, and Palm Oil Fuel Ash Incorporation
by Ghasan Fahim Huseien, Zahraa J. Hussein, Ziyad Kubba, Bryukhov Mikhail Nikolaevich and Jahangir Mirza
Minerals 2023, 13(8), 1096; https://doi.org/10.3390/min13081096 - 17 Aug 2023
Cited by 1 | Viewed by 1177
Abstract
Alkali-activated binders have become popular in the construction industry for their eco-friendly attributes. Various wastes from industries and agricultural sectors containing high concentrations of aluminosilicate and calcium oxides can be used to design these binders. This study evaluated the effect of high-volume granulated [...] Read more.
Alkali-activated binders have become popular in the construction industry for their eco-friendly attributes. Various wastes from industries and agricultural sectors containing high concentrations of aluminosilicate and calcium oxides can be used to design these binders. This study evaluated the effect of high-volume granulated blast furnace slag, fly ash, and palm oil fuel ash additions on the bond strength performance of the proposed geopolymer mortars. Various levels of slag (50, 60, and 70%) and fly ash were substituted by palm oil fuel ash to determine the impact of SiO2:Al2O3, CaO:SiO2, and CaO:Al2O3 and their proportions on the geopolymerization process and the strength performance of the designed mortars. The bond strength performance of the mortars was assessed in terms of slant shear, flexural, and splitting tensile strength tests. The mineral properties of the designed mortars were obtained using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared measurements. The incorporation of fly ash and palm oil fuel ash in the mortars caused a considerable decrease in the CaO:SiO2 and CaO:Al2O3 ratios, thus reducing the geopolymerization process and strength performance. The reduction in slag from 70% to 50% was counterbalanced by the increasing content of fly ash and palm oil fuel ash, which led to a drop in the compressive strength from 97 MPa to 56 MPa. In each level of slag, the replacement of fly ash by up to 10% palm oil fuel ash added more loss in strength values. In addition, the surface morphology of prepared mortars with lower palm oil fuel ash content was significantly enhanced, indicating the presence of less porosity and unreacted particles. The achieved mortars were asserted to be extremely well matched with the concrete substrates, offering effective binders for widespread construction uses. Full article
(This article belongs to the Special Issue Geomaterials: Compositional, Mineralogical and Textural Features)
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19 pages, 8335 KiB  
Article
Geochemical Characteristics and Geological Significance of Black Shale at the Bottom of the Mufushan Formation in the Lower Cambrian, Lower Yangtze Platform, South China
by Jiaqi Li, Zhihong Kang, Zhijiang Kang and Xuemei Zhang
Minerals 2023, 13(8), 1095; https://doi.org/10.3390/min13081095 - 16 Aug 2023
Viewed by 1422
Abstract
Black shale, as an important unconventional energy resource, has attracted significant attention in recent years. By studying its sedimentary and geochemical characteristics, it is possible to reconstruct ancient depositional environments and paleoclimatic conditions. The Lower Cambrian black shale is widely distributed in the [...] Read more.
Black shale, as an important unconventional energy resource, has attracted significant attention in recent years. By studying its sedimentary and geochemical characteristics, it is possible to reconstruct ancient depositional environments and paleoclimatic conditions. The Lower Cambrian black shale is widely distributed in the Lower Yangtze region, but its tectonic background and provenance have been subject to debate. In this study, we conducted geochemical testing and analysis on samples collected from the basal black shale of the Mufushan Formation in the Mufushan section, Nanjing. The Th/Sc-Zr/Sc diagram indicates that the black shale of the Mufushan Formation has not undergone sedimentary recycling. Analysis of major element ratios, rare earth element (REE) distribution patterns, δEu, (La/Yb)N, and the La/Th-Hf and La/Yb-∑REE discrimination diagrams suggest that the source rocks of the black shale mainly consist of granites and sedimentary rocks rich in ferromagnesian minerals, representing felsic rocks derived from the upper crust, with some involvement of mafic rocks. Considering the provenance attributes, geological age relationships, and tectonic evolution of the South China continent, the granite component in the source rocks is inferred to have formed during Neoproterozoic magmatic activity, and the source area corresponds to the Jiangnan Orogenic Belt. Analysis of K2O + Na2O-SiO2, K2O/Na2O-SiO2/Al2O3, La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 diagrams suggests that the source area of the Mufushan Formation black shale was a passive continental margin. Full article
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18 pages, 17780 KiB  
Article
Development of a Hybrid Fixed-Wing UAV Aeromagnetic Survey System and an Application Study in Chating Deposit
by Ning Lu, Yongzai Xi, Hongshan Zheng, Weidong Gao, Yongbo Li, Yu Liu, Zhiqiang Cui, Guixiang Liao and Junjie Liu
Minerals 2023, 13(8), 1094; https://doi.org/10.3390/min13081094 - 16 Aug 2023
Cited by 2 | Viewed by 1241
Abstract
In recent years, the development of airborne magnetic survey technology based on unmanned aerial vehicles (UAVs) has been rapidly advancing. The commonly used systems are the fixed-wing UAV-based, multi-rotors UAV-based, and unmanned helicopters-based magnetic survey systems. And, a type of hybrid UAV that [...] Read more.
In recent years, the development of airborne magnetic survey technology based on unmanned aerial vehicles (UAVs) has been rapidly advancing. The commonly used systems are the fixed-wing UAV-based, multi-rotors UAV-based, and unmanned helicopters-based magnetic survey systems. And, a type of hybrid UAV that uses a vertical takeoff and landing (VTOL) and fixed-wing cruise mode is increasingly being used to carry airborne magnetic survey systems. To meet the requirements of most UAVs for small-sized and lightweight payloads, a miniature magnetic survey system was developed and integrated into a hybrid fixed-wing UAV and formed an aeromagnetic survey system. And, a peripheral mineral exploration test was conducted in a known porphyry copper–gold deposit in southeastern China using the system. By processing the collected magnetic data with 3D inversion of susceptibilities, potential ore-bearing intrusive rocks were quickly identified and delineated, providing clues for peripheral mineral exploration in the mining area. Full article
(This article belongs to the Special Issue Gravity and Magnetic Methods in Mineral Exploration)
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15 pages, 4430 KiB  
Article
Obsidian Artifacts from Multiple Sources and Subsources at Valdesi in Western Sicily
by Robert H. Tykot, Vincenza Forgia and Franco Foresta Martin
Minerals 2023, 13(8), 1093; https://doi.org/10.3390/min13081093 - 16 Aug 2023
Viewed by 1332
Abstract
Forty-two obsidian artifacts excavated at the site of Valdesi in western Sicily were analyzed to determine their geological sources and to reconstruct trade patterns. Non-destructive analysis was performed using a portable, non-destructive X-ray fluorescence spectrometer, with the calibrated element’s composition values compared directly [...] Read more.
Forty-two obsidian artifacts excavated at the site of Valdesi in western Sicily were analyzed to determine their geological sources and to reconstruct trade patterns. Non-destructive analysis was performed using a portable, non-destructive X-ray fluorescence spectrometer, with the calibrated element’s composition values compared directly with a dataset of geological samples from the Mediterranean and European sources that were analyzed with the same instrument. The results, based on straightforward X-Y graphs using the trace elements Rb, Sr, Y, Zr, and Nb, showed the presence of obsidian from two subsources on Lipari (Gabellotto Gorge, Canneto Dentro), two on Pantelleria (Balata dei Turchi, Lago di Venere), and one on Sardinia. The majority coming from Lipari coincided with the location of Valdesi, and nearly 20% came from Pantelleria, both consistent with the overall distribution patterns for Sicily, while the one from Sardinia is a unique discovery. These results are discussed in terms of the time period and context for Valdesi, as well as the open-water and land-based routes that must have been taken. Full article
(This article belongs to the Special Issue Application of Spectrometric Analyses to Cultural Heritage)
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21 pages, 12650 KiB  
Article
Utilizing Remote Sensing and Satellite-Based Bouguer Gravity data to Predict Potential Sites of Hydrothermal Minerals and Gold Deposits in Central Saudi Arabia
by Amr Abd El-Raouf, Fikret Doğru, Islam Azab, Lincheng Jiang, Kamal Abdelrahman, Mohammed S. Fnais and Omar Amer
Minerals 2023, 13(8), 1092; https://doi.org/10.3390/min13081092 - 15 Aug 2023
Cited by 1 | Viewed by 1884
Abstract
This article aims to aid in exploring and forecasting hydrothermal minerals and gold deposits in Central Saudi Arabia (SA), with a focus on structural contexts. Remote sensing (RS) and satellite-based Bouguer gravity (SBG) data were integrated in order to create a mineral prediction [...] Read more.
This article aims to aid in exploring and forecasting hydrothermal minerals and gold deposits in Central Saudi Arabia (SA), with a focus on structural contexts. Remote sensing (RS) and satellite-based Bouguer gravity (SBG) data were integrated in order to create a mineral prediction map for the researched location. Data from the Landsat Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) were transformed and enhanced using a variety of approaches. The delineation of hydrothermal alteration zones (HAZs) and highlighting of structural discontinuities in the OLI data were made possible using band ratios and oriented principal component analysis (PCA). Additionally, the underlying structural features were successfully exposed by processing the SBG using a variety of edge detection techniques, like the analytical signal (AS), total horizontal derivative (THD), tilt angle (TA), horizontal tilt angle (TDX), theta map (TM), horizontal derivative of the tilt derivative (HD_TDR), horizontal gradient of the tilt angle (HGTA), tilt angle of the analytical signal (TAAS), and soft sign function (SF). As a result, more prominent lineaments were found in the NW–SE, NNW–SSE, NE–SW, and NNE–SSW directions than in the N–S and E–W directions. The GIS incorporated surface/subsurface geological structure density maps with zones of hydrothermal alteration. It was found that the lineaments derived from the analysis of the RS and SBG data were more in line with the HAZs, which demonstrated the common connection between alteration zones and deep lineaments. The findings revealed a mineral prediction map with extremely low to extremely high probabilities. Overall, combining RS and SBG data effectively identified probable mineralization sites associated with hydrothermal processes and made it easier to create this study’s final predictive mineralization map. Full article
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23 pages, 7160 KiB  
Article
The Mineral Chemistry of Magnetite and Its Constraints on Ore-Forming Mechanism in the Sandaozhuang Skarn-Type W-Mo Deposit in East Qinling, China
by Zhijie Zeng, Uzair Siddique, Miaojun Sun, Qin Gao, Yanting Chen, Lei Chen and Zilong Li
Minerals 2023, 13(8), 1091; https://doi.org/10.3390/min13081091 - 15 Aug 2023
Viewed by 1422
Abstract
The Sandaozhuang super-large W-Mo deposit is located in the southern margin of the North China Craton, within the well-known East Qinling Mo mineralization belt, and is one of the typical skarn-type W-Mo deposits in China. Based on EMPA and LA-ICP-MS analyses, major and [...] Read more.
The Sandaozhuang super-large W-Mo deposit is located in the southern margin of the North China Craton, within the well-known East Qinling Mo mineralization belt, and is one of the typical skarn-type W-Mo deposits in China. Based on EMPA and LA-ICP-MS analyses, major and trace elements were presented, and the mineral chemistry of magnetite at various mineralization stages was discussed. Combining field observations, petrography, and geochemical characteristics, the magnetite at the Sandaozhuang deposit can be classified into three types, namely early-magmatic-stage high-temperature magnetite (Mag1), potassic-alteration-stage magnetite (Mag2), and retrograde-alteration-stage magnetite (Mag3). The Mag1 and Mag2 magnetites primarily occurred in granites in association with potassium (K) feldspar and biotite, whereas Mag3 is associated with metallic sulfide minerals that occurred mainly in vein-like structures in skarn. The three magnetites Mag1, Mag2, and Mag3 can be distinguished as having magmatic, magmatic–hydrothermal transition, and hydrothermal origins, respectively. All three types of magnetite exhibit a depletion of high-field-strength elements (HFSEs) such as Zr, Hf, Nb, Ta, and Ti, and large-ion lithophile elements (LILEs) including Rb, K, Ba, and Sr, compared to the mean continental crust composition. Conversely, they are enriched in elements such as Sn, Mo, V, Cr, Zn, and Ga. Mag3 showed no significant depletion of Co, Ni, Cu, and Bi, indicating that the influence of coexisting sulfides on the composition of magnetite at the Sandaozhuang deposit is limited. There are systematic variations in major and trace elements from Mag1 to Mag3, which exhibited similar patterns in trace element spider and rare earth element diagrams, and Y/Ho ratio, indicating a consistent source for the three types of magnetite. The changes in V and Cr contents and (Ti + V) vs. (Al + Mn) diagram of magnetite at the Sandaozhuang deposit reflected the evolution of ore-forming fluids with an initial increase in oxygen fugacity and a subsequent decrease, as well as a gradual decrease in temperature during skarn mineralization. The early high-temperature and high-oxygen-fugacity magmatic fluids became W and Mo enriched by hydrothermal fluid interaction. The rapid change in fluid properties during the retrograde alteration stage led to the precipitation of scheelite and molybdenite. Full article
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20 pages, 8957 KiB  
Article
Late Paleozoic Tectonic Evolution of the Northern Great Xing’an Range, Northeast China: Constraints from Carboniferous Magmatic Rocks in the Wunuer Area
by Liyang Li, Chuanheng Zhang and Zhiqiang Feng
Minerals 2023, 13(8), 1090; https://doi.org/10.3390/min13081090 - 15 Aug 2023
Viewed by 848
Abstract
Northeast China composes the main part of the Central Asian Orogenic Belt. Traditionally, Northeast China has been considered a collage of several microcontinental blocks. However, the tectonic evolution of these blocks remains uncertain. Igneous rocks can be used to infer the magmatic histories [...] Read more.
Northeast China composes the main part of the Central Asian Orogenic Belt. Traditionally, Northeast China has been considered a collage of several microcontinental blocks. However, the tectonic evolution of these blocks remains uncertain. Igneous rocks can be used to infer the magmatic histories of the blocks and thus help reconstruct their evolution. In this study, we present new zircon U–Pb and whole-rock geochemical data for Carboniferous igneous rocks from the Wunuer area, northern Great Xing’an Range, Northeast China, to constrain the Carboniferous amalgamation of the united Xing’an–Erguna and Songnen–Zhangguangcai Range massifs. On the basis of zircon U–Pb dating results, we identify two main stages of magmatism, i.e., early Carboniferous (332–329 Ma) and late Carboniferous (312–310 Ma). The early Carboniferous igneous rocks include diorites and granodiorites, with the former being classified as calc-alkaline to tholeiitic and the latter as tholeiitic. Both rock types are enriched in Th and U and depleted in Nb and Ti. The rocks display slightly fractionated rare earth element (REE) patterns, with an enrichment in light REEs and a depletion in heavy (H)REEs. The geochemical characteristics of the early Carboniferous rocks indicate that they formed in a subduction-related continental-arc setting. The late Carboniferous igneous rocks include monzogranites and syenogranites, both of which are classified as high-K calc-alkaline rocks and show enrichment in Th, U, and Rb and depletion in Nb and Ti. The rocks display strongly fractionated REE patterns, with an enrichment in light REEs and a depletion in HREEs. The geochemical characteristics of the late Carboniferous rocks indicate that they formed in a syn-collisional tectonic setting. Combining the new geochronological and geochemical results and inferred tectonic settings with regional magmatic data, we propose a new three-stage model to interpret the late Paleozoic tectonic evolution of the united Xing’an–Erguna and Songnen–Zhangguangcai Range massifs of Northeast China: (1) early Carboniferous (360–340 Ma) subduction of the Paleo-Asian oceanic plate beneath the united Xing’an–Erguna Massif and formation of the Wunuer oceanic basin in the Yakeshi area; (2) early to late Carboniferous (340–310 Ma) sustained subduction of the Paleo-Asian oceanic plate beneath the united Xing’an–Erguna Massif and initiation of subduction of the Wunuer oceanic basin; and (3) late Carboniferous–early Permian (310–275 Ma) syn-collisional to post-collisional tectonic transition between the united Xing’an–Erguna Massif and the Songnen–Zhangguangcai Range Massif. Full article
(This article belongs to the Special Issue Geochronology, Geochemistry and Petrogenesis of Magmatic Rocks)
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10 pages, 1767 KiB  
Article
The Evolution of Mineral Hardness Reveals Both Changing Parageneses and Preservational Bias in the Mineralogical Record
by Marko Bermanec, Ahmed M. Eleish, Shaunna M. Morrison, Anirudh Prabhu, Michael L. Wong and Robert M. Hazen
Minerals 2023, 13(8), 1089; https://doi.org/10.3390/min13081089 - 15 Aug 2023
Cited by 3 | Viewed by 1227
Abstract
A survey of the average Mohs hardness of minerals throughout Earth’s history reveals a significant and systematic decrease from >6 in presolar grains to ~5 for Archean lithologies to <4 for Phanerozoic minerals. Two primary factors contribute to this temporal decrease in the [...] Read more.
A survey of the average Mohs hardness of minerals throughout Earth’s history reveals a significant and systematic decrease from >6 in presolar grains to ~5 for Archean lithologies to <4 for Phanerozoic minerals. Two primary factors contribute to this temporal decrease in the average Mohs hardness. First, selective losses of softer minerals throughout billions of years of near-surface processing lead to preservational biases in the mineral record. Second, changes in the processes of mineral formation play a significant role because more ancient refractory stellar phases and primary igneous minerals of the Hadean/Archean Eon are intrinsically harder than more recently weathered products, especially following the Paleoproterozoic Great Oxidation Event and the production of Phanerozoic biominerals. Additionally, anthropogenic sampling biases resulting from the selective exploration and curation of the mineralogical record may be superimposed on these two factors. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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17 pages, 4862 KiB  
Article
Characteristics of Gold Minerals in Gold Concentrate with a High Copper Content and Effective Gold Recovery via Flotation and Ammonia Pretreatment–Cyanidation Leaching
by Yuebing Liu and Shuming Wen
Minerals 2023, 13(8), 1088; https://doi.org/10.3390/min13081088 - 15 Aug 2023
Viewed by 1454
Abstract
The characteristics of ultrafine gold minerals in gold concentrate with a high copper content produced by a large gold mining company in Shandong Province were determined via chemical composition analysis, phase analysis, and mineral liberation analysis. The results showed that the concentrate contained [...] Read more.
The characteristics of ultrafine gold minerals in gold concentrate with a high copper content produced by a large gold mining company in Shandong Province were determined via chemical composition analysis, phase analysis, and mineral liberation analysis. The results showed that the concentrate contained 48.13 g/t gold, which was mainly in the form of native gold and electrum. Regarding the gold mineral particles, 57.65% were completely liberated and 35.75% were associated with chalcopyrite and pyrite. The remainder mainly comprised wrapped intergrowths. The cumulative distributions of native gold and electrum fractions with diameters of less than 75 µm were 82.55% and 90.15%, respectively. Enhanced Cu–S bulk flotation, and then, Cu–S separation from the raw material were proposed to effectively enrich the gold minerals and decrease the treatment throughput during the leaching operation. The optimized conditions yielded a concentrate with a high copper content (3.89% Cu and 545.62 g/t Au contents, and 83.15% Cu and 77.54% Au recoveries) and a concentrate with a high sulfur content (0.059% Cu and 15.03 g/t Au contents, and 83.15% Cu and 21.28% Au recoveries). The capacity of the subsequent leaching process was reduced by 25%. Ammonia pretreatment was introduced to decrease the adverse effect of copper on cyanidation leaching for the copper concentrate. Under the optimized leaching conditions, gold dissolution reached 99.76%, which was approximately 4% higher than that obtained via direct leaching. The NaCN consumption decreased over 10 kg/t. These results could serve as a valuable reference for the economic and green utilization of gold resources from concentrate with a high copper content. Full article
(This article belongs to the Special Issue Application of Advanced Quantum Chemistry in Mineral Flotation)
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16 pages, 7279 KiB  
Article
Influences of Water Content on Acousto-Mechanical Properties and Failure Behaviors of Triaxially Compressed Shale
by Sui Zhang, Fuming Cai, Yangbing Cao and Qiang Yan
Minerals 2023, 13(8), 1087; https://doi.org/10.3390/min13081087 - 15 Aug 2023
Viewed by 797
Abstract
Due to the extreme water sensitivity of shale, the excavation of shale underground engineering is prone to major disaster accidents such as roof falls and collapses. However, current investigations have failed to fully explain the mechanisms by which water content affects shale damage [...] Read more.
Due to the extreme water sensitivity of shale, the excavation of shale underground engineering is prone to major disaster accidents such as roof falls and collapses. However, current investigations have failed to fully explain the mechanisms by which water content affects shale damage behaviors. In this study, the acousto-mechanical properties and failure behaviors of laminated shale under different confining pressures σ3 are investigated with the aid of AE monitoring for three different water content states. The results show that the shale strength decreases with the increase of the water content, but it increases as the confining pressure σ3 increases. For the shale, the change in the wetting angle and the distance between the centroids of the two adjacent particles inside the bedding plane is more prominent than the surrounding shale matrix, and the swelling pressure is generated among the clay minerals, which are the two main mechanisms for the bedding-participating failure and the shale softening after immersion. Moreover, with the increase of the water content and σ3, the damage mode of shale specimens gradually changes from tension damage to shear damage. Controlled by bedding, shale failure shows significant suddenness without clear acoustical precursors. This study provides experimental and theoretical bases for the stability analysis of shale underground engineering. Full article
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13 pages, 3220 KiB  
Article
Timing of Carbonatite Ultramafic Complexes of the Eastern Sayan Alkaline Province, Siberia: U–Pb (ID–TIMS) Geochronology of Ca–Fe Garnets
by Maria V. Stifeeva, Ekaterina B. Salnikova, Valentina B. Savelyeva, Alexander B. Kotov, Yulia V. Danilova, Ekaterina P. Bazarova and Boris S. Danilov
Minerals 2023, 13(8), 1086; https://doi.org/10.3390/min13081086 - 14 Aug 2023
Cited by 1 | Viewed by 1010
Abstract
In this study, we present the results of U–Pb (ID-TIMS) geochronological studies of calcic garnet from the alkaline ultramafic complexes of Eastern Sayan province (eastern Siberia). New U–Pb ID–TIMS garnet ages obtained from different rocks of Bolshaya Tagna (632 ± 2 Ma) and [...] Read more.
In this study, we present the results of U–Pb (ID-TIMS) geochronological studies of calcic garnet from the alkaline ultramafic complexes of Eastern Sayan province (eastern Siberia). New U–Pb ID–TIMS garnet ages obtained from different rocks of Bolshaya Tagna (632 ± 2 Ma) and Srednaya Zima intrusions (624 ± 5 Ma), as well as previously published garnet ages of the Belaya Zima complex (646 ± 6 Ma), allow us to constrain the timing and duration of episodes of alkaline ultramafic magmatism in Eastern Sayan province (619–651 Ma). Variations in the chemical compositions of rocks from three massifs indicate that the parental melts were separated from different magmatic chambers generated during the same episode of mantle melting. This study further highlights garnet U–Pb dating as a potentially robust, high-resolution geochronometer to constrain the evolution of the main pulse of alkaline ultramafic magmatism in the large magmatic provinces. Full article
(This article belongs to the Special Issue Large Igneous Provinces: Research Frontiers)
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17 pages, 6035 KiB  
Article
The Fontanamare Discovery (Sardinia Coast, Italy), a Case of Underwater Corrosion of Bronze Coins
by Tilde de Caro, Fiammetta Susanna, Mauro Francesco La Russa and Andrea Macchia
Minerals 2023, 13(8), 1085; https://doi.org/10.3390/min13081085 - 14 Aug 2023
Cited by 1 | Viewed by 1052
Abstract
This study reports the analytical approach towards nine coins found in wreck A of Fontanamare for understanding the complex corrosion processes that take place in underwater conditions. Optical microscopy (OM) combined with micro-Raman (µ-Raman) spectroscopy, X-ray diffractometry (XRD), and scanning electron microscopy with [...] Read more.
This study reports the analytical approach towards nine coins found in wreck A of Fontanamare for understanding the complex corrosion processes that take place in underwater conditions. Optical microscopy (OM) combined with micro-Raman (µ-Raman) spectroscopy, X-ray diffractometry (XRD), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM and EDS) were used to analyze the nature and the microstructure of the corrosion patina in comparison with the non-degraded state of coins. Three main types of corrosion patina based on copper, lead chloride, and carbonate were identified: black, white, and green, and the obtained results demonstrate the complex corrosion processes that take place in underwater conditions. To better understand the role played by different chemical and physical parameters in the corrosion of bronze artefacts in an underwater environment, this study attempts to understand the nature of the patinas on the coins in relation to the specific structural and environmental parameter variation. Full article
(This article belongs to the Special Issue Application of Spectrometric Analyses to Cultural Heritage)
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0 pages, 8464 KiB  
Article
Noise Characteristics and Denoising Methods of Long-Offset Transient Electromagnetic Method
by Yang Xu, Xingbing Xie, Lei Zhou, Biao Xi and Liangjun Yan
Minerals 2023, 13(8), 1084; https://doi.org/10.3390/min13081084 - 14 Aug 2023
Cited by 1 | Viewed by 1330 | Correction
Abstract
The advantages of the long-offset transient electromagnetic method include deep detection and sensitive response to resistivity anomalies. It is widely used in underground mineral resources exploration, fluid identification in petroleum reservoirs, hydraulic fracturing, and dynamic residual oil and gas monitoring. After the primary [...] Read more.
The advantages of the long-offset transient electromagnetic method include deep detection and sensitive response to resistivity anomalies. It is widely used in underground mineral resources exploration, fluid identification in petroleum reservoirs, hydraulic fracturing, and dynamic residual oil and gas monitoring. After the primary field signal is turned off, grounded electrodes or coils are used to observe the secondary eddy field. The secondary field signal decays quickly and has a large dynamic range and a wide frequency band but is easily affected by various natural and human electromagnetic interferences. Therefore, noise reduction and distortion correction are important issues in the processing of transient electromagnetic data. This paper proposes a systematic noise interference suppression process. Multi-period and positive–negative bipolar signal stackings were used to remove random noise and suppress DC offset signals. Then, a time-domain inverse digital recursive method was applied to remove characteristic frequency signals, e.g., power frequency signals and their harmonic interference. A standard noise-free signal was constructed through forward modeling simulation and verified by adding different types of noise. Finally, high-quality transient electromagnetic secondary field attenuation signals were obtained through overlapping windowing technology. We applied this algorithm to obtain electromagnetic data from dynamic monitoring of hydraulic fracturing in Fuling shale gas and from a copper–iron metal mine in Daye City, demonstrating its effectiveness. Full article
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21 pages, 7691 KiB  
Article
Effects of Metasomatism on Granite-Related Mineral Systems: A Boron-Rich Open Greisen System in the Highiş Granitoids (Apuseni Mountains, Romania)
by Andrea Varga, Attila Pozsár, Norbert Zajzon, Boglárka Topa, Zsolt Benkó, Elemér Pál-Molnár and Béla Raucsik
Minerals 2023, 13(8), 1083; https://doi.org/10.3390/min13081083 - 14 Aug 2023
Cited by 1 | Viewed by 1675
Abstract
Greisenization is typically linked with highly fractionated granites and is often associated with hydrothermal vein systems. Late to postmagmatic metasomatic processes involve the enrichment of volatile components such as boron and halogens as well as several metallic elements. The purpose of this study [...] Read more.
Greisenization is typically linked with highly fractionated granites and is often associated with hydrothermal vein systems. Late to postmagmatic metasomatic processes involve the enrichment of volatile components such as boron and halogens as well as several metallic elements. The purpose of this study is to reveal the main metasomatic effects and paragenetic sequences of the related mineralizations in Highiş granitoids, Romania. In a natural outcrop, more than 30 samples were collected from granitoids, felsic veins, and country rocks. We carried out a detailed mineralogical and petrological characterization of carefully selected samples using X-ray powder diffractometry, electron microprobe analysis, and microscopic methods together with K–Ar ages of whole rocks and K-bearing minerals. Several characteristic features of albitization, sericitization, tourmalinization, epidotization, and hematitization were recognized in the studied samples. Crystallization of quartz, K-feldspar, and magnetite represents the first stage during the magmatic-hydrothermal transition. The mineral assemblage of albite, sericite, schorl, and quartz originates from the early and main stages of greisenization. While the subsequent mineral assemblages, which predominantly include dravite, specular hematite, and epidote, are closely related to the late vein-depositing stage. We propose that the study area could belong to a boron-rich open greisen system in the apical portion of Guadalupian A-type granite. Based on a new hypothesis, the previously published Permian crystallization ages (between ~272 Ma and ~259 Ma) could be homogenized and/or partially rejuvenated during the hydrothermal mineralization processes due to uraniferous vein minerals. Additionally, the Highiș granite-related system suffered a Cretaceous thermal overprint (between ~100 Ma and ~96 Ma). The results may help to understand the evolution of highly evolved granite intrusions worldwide and improve our knowledge of the effect of hydrothermal mineralization processes on the emplacement ages. Full article
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18 pages, 6106 KiB  
Article
Genesis and Formation of the Tuwaishan Gold Deposit in Hainan Island, South China: Implications from H-O-S Isotopes
by Yuheng Liu, Jingwen Mao, Jun Hu, Lei Wang and Deming Xu
Minerals 2023, 13(8), 1082; https://doi.org/10.3390/min13081082 - 14 Aug 2023
Viewed by 849
Abstract
The Tuwaishan gold deposit is located at the northeastern end of the Gezhen shear zone in the western part of Hainan Island, South China. It is one of a series of similar gold deposits hosted in the Mesoproterozoic basement rocks and structurally controlled [...] Read more.
The Tuwaishan gold deposit is located at the northeastern end of the Gezhen shear zone in the western part of Hainan Island, South China. It is one of a series of similar gold deposits hosted in the Mesoproterozoic basement rocks and structurally controlled by the Gezhen shear zone. The hydrothermal ore-forming period can be divided into quartz-pyrite-arsenopyrite stage, quartz-pyrite-base metal sulfides stage and quartz-carbonate stage. Eleven gold-bearing quartz vein samples yield δDV-SMOW and δ18OV-SMOW values of −75.9‰ to −54.4‰ and +8.1‰ to +13.7‰, respectively, and the corresponding δ18Owater values range from +3.1‰ to +8.7‰. In addition, the pyrite separates from 14 ore samples yield δ34S values of +4.5‰ to +7.9‰. The H-O-S isotopic data, along with fluid properties of the Tuwaishan and other gold deposits along the Gezhen shear zone, suggest that the ore-forming fluid and materials are of metamorphic rather than magmatic origin. Hence, we propose that the Tuwaishan gold deposit is best classified as orogenic gold deposit that resulted from regional metamorphism. Considering that the Mesoproterozoic basement rocks have experienced amphibolite facies metamorphism prior to the gold mineralization, the metamorphic devolatilization of the Ordovician-Silurian rocks at depth would provide a realistic source of fluid, gold and sulfur for the Tuwaishan and other gold deposits of the Gezhen gold belt. Full article
(This article belongs to the Special Issue Understanding Hydrothermal Ore Deposits)
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23 pages, 11364 KiB  
Article
The Behavior of Rare Earth Elements during Green Clay Authigenesis on the Congo Continental Shelf
by Germain Bayon, Pierre Giresse, Hongjin Chen, Marie-Laure Rouget, Bleuenn Gueguen, Gabriel Ribeiro Moizinho, Jean-Alix Barrat and Daniel Beaufort
Minerals 2023, 13(8), 1081; https://doi.org/10.3390/min13081081 - 14 Aug 2023
Cited by 3 | Viewed by 1396
Abstract
Clay mineral authigenesis at continental margins plays an important role in global marine element cycles. However, despite being increasingly used as tracers for both modern and past oceanographic conditions, the behavior of the rare earth elements (REEs) and their isotopes during marine clay [...] Read more.
Clay mineral authigenesis at continental margins plays an important role in global marine element cycles. However, despite being increasingly used as tracers for both modern and past oceanographic conditions, the behavior of the rare earth elements (REEs) and their isotopes during marine clay authigenesis still remains poorly known. In this study, we report on a detailed geochemical investigation of glauconite from the West African continental shelf, near the mouth of the Congo River. Elemental, neodymium, and hafnium isotope analyses were conducted on both acid leachate and separated clay-size fractions of glauconite pellets, in order to investigate the behavior of REE during the formation of authigenic clays. Our data indicate that kaolinite dissolution and subsequent Fe-bearing clay authigenesis act as a net source of REEs to seawater. We show that enhanced glauconitization, as inferred from increasing Fe and K contents, is accompanied by significant decoupling of the REE toward markedly LREE-enriched shale-normalized patterns in neoformed clay separates. Using both Nd and Hf isotopes and SEM observations, we rule out any seawater influence and argue that this shift primarily reflects the progressively overwhelming presence of insoluble nanocrystals of detrital LREE-rich phosphates, which are known to occur in close association with kaolinite in tropical soils. Due to their marked insolubility in surface environments, such nanocrystals can be preserved during kaolinite dissolution and subsequently incorporated into the aggregates of authigenic green clays forming the peloids. Most strikingly, we show that the combined influence of net REE loss (due to kaolinite dissolution) and decoupling (due to subsequent entrapment of inherited LREE-bearing accessory phases into neoformed clay minerals) is accompanied by preferential release of a dissolved REE fraction characterized by seawater-like distribution patterns. These findings reinforce the emerging view that clay mineral dissolution and authigenesis at continental margins possibly play a major role in marine REE cycling. Full article
(This article belongs to the Special Issue Formation and Evolution of Glauconite. New Scale Approach)
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