Minerals

4 pages, 177 KiB

Open AccessEditorial

Editorial for the Special Issue “Environment and Geochemistry of Sediments”

by Marianna Kulkova and Dmitry Subetto

Minerals 2023, 13(5), 709; https://doi.org/10.3390/min13050709 - 22 May 2023

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The geochemical characteristics of environments can be determined via geochemical studies of sedimentary rocks [...] Full article

(This article belongs to the Special Issue Environment and Geochemistry of Sediments)

24 pages, 22023 KiB

Open AccessArticle

Detrital Zircon LA-ICP-MS U-Pb Ages of the North Liaohe Group from the Lianshanguan Area, NE China: Implications for the Tectonic Evolution of the Paleoproterozoic Jiao-Liao-Ji Belt

by Jinhui Gao, Weimin Li, Yongjiang Liu, Yingli Zhao, Tongjun Liu and Quanbo Wen

Minerals 2023, 13(5), 708; https://doi.org/10.3390/min13050708 - 22 May 2023

Cited by 3 | Viewed by 1548

Abstract

The Liaohe Group, which is a significant lithostratigraphic unit within the Paleoproterozoic Jiao-Liao-Ji Belt situated between the Longgang and Liaonan-Nangrim blocks, comprises the Langzishan, Li’eryu, Gaojiayu, Dashiqiao, and Gaixian formations, which are characterized mainly by a clastic-rich sequence with an interlayered bimodal-volcanic sequence, [...] Read more.

The Liaohe Group, which is a significant lithostratigraphic unit within the Paleoproterozoic Jiao-Liao-Ji Belt situated between the Longgang and Liaonan-Nangrim blocks, comprises the Langzishan, Li’eryu, Gaojiayu, Dashiqiao, and Gaixian formations, which are characterized mainly by a clastic-rich sequence with an interlayered bimodal-volcanic sequence, carbonate-rich sequence, and (meta-)pelite-rich sequence. Currently, the tectonic background and evolution of the Liaohe Group remain contentious. Based on the study of detrital zircon geochronology and the zircon trace element characteristics in the Langzishan and Li’eryu formations in the North Liaohe Group in the Lianshanguan area, NE China, this paper reveals the formations’ provenances, depositional ages, and relationships with Paleoproterozoic granitoids (the Liao-Ji granites). The present results, in conjunction with previous studies, indicate that the depositional age of the Langzishan Formation is 2136 Ma and that of the Li’eryu Formation is 1974 Ma. The provenances of the Langzishan Formation and the Li’eryu Formation are mainly characterized by Neoarchean-to-early-Paleoproterozoic basement rocks (~2.6–2.4 Ga) and the Liao-Ji granites (~2.2–2.0 Ga), respectively. Moreover, the coeval mafic and metasedimentary rocks of the Liaohe Group exhibit characteristics of an extensional environment, which is represented by the tectonic setting of a back-arc basin. Notably, the Upper Langzishan Formation records a prominent shift in sedimentary environment from a passive continental margin to an active continental margin. In terms of the tectonic evolution of the North Liaohe Group and the Jiao-Liao-Ji Belt, our proposed model suggests that the Archean basement rocks in the northern part of the continental block, along with a limited contribution from the Paleoproterozoic Liao-Ji granites, served as the primary sources for the Langzishan Formation. Subsequently, the rapid deposition of the Li’eryu Formation was influenced by intense magmatism and subsequent erosion of the subduction-related magmatic arc (the Liao-Ji granites) within a back-arc basin environment. Lastly, the deposition of clastic materials from the Longgang blocks and the Liao-Ji granites resulted in the formation of the Gaojiayu, Dashiqiao, and Gaixian formations. Full article

(This article belongs to the Special Issue Formation and Evolution of the Continental Crust in North China Craton during Precambrian)

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23 pages, 21306 KiB

Open AccessArticle

Typomorphic Features and Source of Native Gold from the Sykhoi Log Area Placer Deposits, Bodaibo Gold-Bearing District, Siberia, Russia

by Alexander Lalomov, Antonina Grigorieva, Alexei Kotov and Lidiya Ivanova

Minerals 2023, 13(5), 707; https://doi.org/10.3390/min13050707 - 22 May 2023

Cited by 3 | Viewed by 1348

Abstract

The Bodaibo gold-bearing district in the Lena gold province of Siberia is one of the largest and oldest placer gold-bearing provinces in the world. Approximately 1650 tons of gold has been extracted from the region. Precise studies on the source of these unique [...] Read more.

The Bodaibo gold-bearing district in the Lena gold province of Siberia is one of the largest and oldest placer gold-bearing provinces in the world. Approximately 1650 tons of gold has been extracted from the region. Precise studies on the source of these unique placer deposits are lacking and still controversial. Native gold from four different locations was gathered to investigate its morphology, chemical signatures, structure and inclusions. Some data on primary bedrock mineralization were obtained from the published literature. The linear weathering crusts developed along the zones of disjunctive dislocations near the Sukhoi Log gold deposit were researched. If they coincided with zones of low-grade veinlet-disseminated gold–quartz–sulphide mineralization with small gold grain sizes, a supergene replacement of primary mineralization was known to have occurred, accompanied by the formation of gold-rich rims and an increase in the size, content and purity of gold. Such mineralization associated with linear weathering crusts can be a source of local eluvial–proluvial placers, while placers of large valleys are formed due to low-sulphide gold–quartz lodes. Full article

(This article belongs to the Special Issue Native Gold as a Specific Indicator Mineral for Gold Deposits)

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14 pages, 12382 KiB

Open AccessArticle

Estimating Perspectives of Oil and Gas in New Strata in the Southern and Surrounding Dayangshu Basin

by Yanxu Liu, Yanling Lai, Wenyong Li, Feng Luo, Lijie Wang, Anqi Cao, Zhexin Jiang and Shan Gao

Minerals 2023, 13(5), 706; https://doi.org/10.3390/min13050706 - 22 May 2023

Cited by 3 | Viewed by 827

Abstract

On the basis of elaborating on the regional geological background, this paper analyzes the lithological and sedimentary characteristics and explorative prospects of new strata with oil and gas in the southern and surrounding areas of Dayangshu Basin. Based on the latest high-precision airborne [...] Read more.

On the basis of elaborating on the regional geological background, this paper analyzes the lithological and sedimentary characteristics and explorative prospects of new strata with oil and gas in the southern and surrounding areas of Dayangshu Basin. Based on the latest high-precision airborne gravity and magnetic comprehensive survey data, combined with the latest data from geological explorations, physical surveys, and drilling, and the use of basin structure layering combination methods, we clarified the characteristics of the bottom of the Jurassic–Cretaceous and the occurrence characteristics of the Upper Paleozoic in the study area and revealed the determinative effect of multi-period structures on the most important sedimentary layers. Then, we summarized the accumulation conditions and prediction methods of hydrocarbons and proposed the oil and gas prospects of these deep new strata. The results show that the Liuhe Sag in Dayangshu Basin, the depression in the northeast of Longjiang Basin, and the northern parts of the Taikang swell have good source–reservoir–cap combination conditions and favorable structural characteristics for oil and gas, where there is a high potential for exploration. Full article

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

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16 pages, 4332 KiB

Open AccessArticle

Preparation, Structural Characterization and Evaluation of Some Dynamic and Rheological Properties of a New Type of Clay Containing Mastic Material, Clay-Mastic

by Ahmet Gürses and Tahsin Barkın Barın

Minerals 2023, 13(5), 705; https://doi.org/10.3390/min13050705 - 22 May 2023

Cited by 1 | Viewed by 841

Abstract

This study focused on the preparation, structural characterization and evaluation of some dynamic and rheological properties of a new type of mastic material, clay-mastic, which consists of bituminous binders mixed with mineral fillers. For this purpose, mastic samples were prepared by mixing conventional [...] Read more.

This study focused on the preparation, structural characterization and evaluation of some dynamic and rheological properties of a new type of mastic material, clay-mastic, which consists of bituminous binders mixed with mineral fillers. For this purpose, mastic samples were prepared by mixing conventional bitumen (50/70) with organo-montmorillonite (OMMT) in various proportions. X-ray powder diffraction (XRD) spectra and scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM) images of raw clay (MMT), organo-clay (OMMT) and raw bitumen with the prepared mastics were taken, and the changes in the crystallographic properties of the clay and its dispersion characteristics in the bitumen matrix as well as the changes in the morphological properties of the mastic samples were investigated comparatively. In addition, penetration, softening point, flash point, dynamic viscosity, dynamic shear rheometer (DSR) and Fraass breaking point tests were carried out together with those of base bitumen in order to evaluate the properties of the prepared mastic samples in terms of dynamics and rheology. A comparison of the images of raw clay and organo-clay indicated delamination based on surface modification in clay layers in those belonging to organo-clay, and diffractograms of prepared mastic samples showed that the characteristic smectite peak of Montmorillonite shifted to the left gradually with an increasing clay ratio. This shows that due to the successful lyophilic modification on the clay surface, the effective intercalated and even exfoliated dispersion of the clay layers in the bitumen matrix can occur. The penetration viscosity number (PVN) values, defined as a function of penetration and dynamic viscosity, and the penetration index (PI) values, defined as a function of penetration and softening point, were found to be within a well-accepted thermal stability range for all of the prepared mastic samples. For this reason, it was concluded that the sensitivity of the samples to temperature decreased with the addition of organo-clay, thus providing applicability in a wider temperature range. The Fraass breaking point and dynamic viscosity values of the prepared mastic samples decreased and increased, respectively, with an increasing clay ratio, meaning that the addition of organo-clay lead to an increase in the crack resistance of the samples at low temperatures and a decrease in their permeability. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: "Chemical Reactions of Clay Minerals and Their Utilization")

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14 pages, 6520 KiB

Open AccessArticle

Pink to Purple Sapphires from Ilakaka, Madagascar: Insights to Separate Unheated from Heated Samples

by Stefanos Karampelas, Ugo Hennebois, Jean-Yves Mevellec, Vincent Pardieu, Aurélien Delaunay and Emmanuel Fritsch

Minerals 2023, 13(5), 704; https://doi.org/10.3390/min13050704 - 22 May 2023

Cited by 3 | Viewed by 1520

Abstract

The present study is focused on the analysis of zircon inclusions found in pink to purple sapphires from Ilakaka (Madagascar) with an optical microscope, Fourier-transform infrared (FTIR), and micro-Raman spectroscopy in order to update previous knowledge and find insights to separate heated from [...] Read more.

The present study is focused on the analysis of zircon inclusions found in pink to purple sapphires from Ilakaka (Madagascar) with an optical microscope, Fourier-transform infrared (FTIR), and micro-Raman spectroscopy in order to update previous knowledge and find insights to separate heated from unheated samples. In total, 157 zircon inclusions in 15 unheated samples and 74 zircon inclusions in 6 heated samples are analysed using micro-Raman spectroscopy with standardised parameters. The full width at half maximum (FWHM) of the main Raman band due to anti-symmetric stretching vibration ν₃ of the SiO₄ tetrahedron in the zircon structure has been carefully measured. In the unheated samples, it ranges from 6.26 to 21.73 cm⁻¹ with an average of 10.74 cm⁻¹, a median of 10.04 cm⁻¹, and a standard deviation of 2.84 cm⁻¹. On the other hand, it is lower in the heated samples, ranging from 4.83 to 14.97 cm⁻¹ with an average of 7.23 cm⁻¹, median of 7.06 cm⁻¹, and standard deviation of 1.63 cm⁻¹. In our unheated samples, the FWHM was rarely below 7 cm⁻¹. In our heated samples, the FWHM was rarely above 12 cm⁻¹ but mostly below 8 cm⁻¹, with a variation restricted to less than 3 cm⁻¹ in the same sample. The present work will hopefully further contribute to more accurately identifying the low-temperature heat treatment of pink sapphires from Ilakaka, Madagascar. Full article

(This article belongs to the Special Issue Gem Characterisation)

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11 pages, 3979 KiB

Open AccessArticle

In Situ High-Pressure Raman Spectroscopic, Single-Crystal X-ray Diffraction, and FTIR Investigations of Rutile and TiO₂II

by Xiaofeng Lu, Shuchang Gao, Peiyan Wu, Ziyu Zhang, Li Zhang, Xiaoguang Li and Xueqing Qin

Minerals 2023, 13(5), 703; https://doi.org/10.3390/min13050703 - 21 May 2023

Cited by 1 | Viewed by 1400

Abstract

In ultrahigh-pressure (UHP) metamorphic rocks, rutile is an important accessory mineral. Its high-pressure polymorph TiO₂II can be a significant indicator of pressure in the diamond stability field. In the present study, in situ high-pressure Raman spectroscopic measurements of natural rutile in [...] Read more.

In ultrahigh-pressure (UHP) metamorphic rocks, rutile is an important accessory mineral. Its high-pressure polymorph TiO₂II can be a significant indicator of pressure in the diamond stability field. In the present study, in situ high-pressure Raman spectroscopic measurements of natural rutile in UHP eclogite from the main hole of the Chinese Continental Scientific Drilling Project (CCSD) have been conducted up to ~16 GPa. Rutile and recovered TiO₂II have also been analyzed via single-crystal X-ray diffraction and FTIR spectroscopy. The results indicate that (1) the phase transition from rutile to baddeleyite-type TiO₂ terminates at about 16 GPa under compression at ambient temperature; (2) the metastable TiO₂II in the exhumated UHP rocks formed during deep continental subduction can be characterized by a highly distorted octahedral site in the crystal structure. X-ray powder diffraction analyses (with Cu Kα radiation) at ambient conditions are sufficient for identifying the lamellae of TiO₂II within natural rutile based on the angles (2θ) of two strong peaks at 25.5° and 31.5°; (3) rutile and recovered TiO₂II in the continental slabs can contain certain amounts of water during deep subduction and exhumation. The estimated water contents of rutile in the present study range from 1590 to 1780 ppm of H₂O by weight. In the crystal structure of TiO₂II, hydrogen can be incorporated close to the long O-O edges (>2.5143 Å) of the TiO₆ octahedra. Further studies on the pressure–temperature stability of hydroxyls in rutile and TiO₂II may help to understand the transportation and release of water in subducted continental slabs. Full article

(This article belongs to the Special Issue Crystal Structures and Phase Transitions of Minerals at Extreme Conditions)

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13 pages, 4199 KiB

Open AccessArticle

Novel Hydroxyl-Containing Quaternary Ammonium Salt N-(2-Hydroxyethyl)-N, N-Dimethyl-3-[(1-Oxododecyl)amino]-1-Propanaminium: Its Synthesis and Flotation Performance to Quartz

by Benying Wang, Panxing Zhao, Wengang Liu, Wenbao Liu, Ying Guo, Kelin Tong and Xudong Chen

Minerals 2023, 13(5), 702; https://doi.org/10.3390/min13050702 - 21 May 2023

Viewed by 1118

Abstract

In this paper, a novel hydroxyl-containing quaternary ammonium surfactant N-(2-Hydroxyethyl)-N, N-dimethyl-3-[(1-oxododecyl)amino]-1-propanaminium (LPDC) was synthesized and introduced as a collector for the reverse cationic flotation separation of apatite from quartz; the adsorption mechanisms between LPDC and two mineral surfaces were investigated by Fourier transform [...] Read more.

In this paper, a novel hydroxyl-containing quaternary ammonium surfactant N-(2-Hydroxyethyl)-N, N-dimethyl-3-[(1-oxododecyl)amino]-1-propanaminium (LPDC) was synthesized and introduced as a collector for the reverse cationic flotation separation of apatite from quartz; the adsorption mechanisms between LPDC and two mineral surfaces were investigated by Fourier transform infrared spectrometer (FTIR), zeta potential measurements and X-ray photoelectron spectroscopy (XPS) analysis. The micro-flotation tests showed that LPDC exhibited excellent flotation performance. When the pulp was at natural pH and LPDC concentration was 25 mg/L, the apatite concentrate with a P₂O₅ recovery of 95.45% and P₂O₅ grade of 38.94% could be obtained from artificially mixed minerals. FTIR, zeta potential, and XPS analysis indicated that the adsorption of LPDC onto quartz surface is stronger than that onto apatite surface; meanwhile, the adsorption of LPDC onto quartz surface is mainly provided by electrostatic force and hydrogen bonding. Full article

(This article belongs to the Special Issue Advances in Reagents for Mineral Processing)

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17 pages, 9100 KiB

Open AccessArticle

Petrogenesis of Shihuiyao Rare-Metal Granites in the Southern Great Xing’an Range, NE China

by Deyou Sun, Shicheng Wang, Jun Gou, Duo Zhang, Changzhou Deng, Dongguang Yang and Li Tian

Minerals 2023, 13(5), 701; https://doi.org/10.3390/min13050701 - 21 May 2023

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Abstract

Shihuiyao Rb–Nb–Ta-rich granites from the Late Jurassic period are newly discovered rare-metal-bearing granites found in the southern Great Xing’an Range, NE China. Further research of these granites may contribute to better understanding the petrogenesis of rare-metal granites and their associated mineralization mechanisms. The [...] Read more.

Shihuiyao Rb–Nb–Ta-rich granites from the Late Jurassic period are newly discovered rare-metal-bearing granites found in the southern Great Xing’an Range, NE China. Further research of these granites may contribute to better understanding the petrogenesis of rare-metal granites and their associated mineralization mechanisms. The granites are high-silica (SiO₂ = 73.66–77.08 wt%), alkali-rich (K₂O + Na₂O = 8.18–9.49 wt%) and weakly to mildly peraluminous with A/CNK values (molar ratios of Al₂O₃/(CaO + Na₂O + K₂O)) ranging from 1.06 to 1.16. High differentiation indexes (DI = 95–97) and low P₂O₅ contents demonstrate that Shihuiyao rocks are low-P and peraluminous rare-metal granites. Mineral chemistry and whole-rock geochemistry can be used to obtain the following lithological sequence: zinnwaldite granite, muscovite–zinnwaldite granite, amazonite-bearing granite and amazonite pegmatite. The effect of the rare-earth element tetrad; low K/Rb (18.98–32.82), Nb/Ta (2.41–4.64) and Zr/Hf (5.99–8.80) ratios; and the occurrence of snowball-textured quartz suggest that extreme magmatic fractionation might be the key factor that causes Rb–Nb–Ta enrichment. Full article

(This article belongs to the Special Issue Mineralization in Subduction Zone)

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12 pages, 6001 KiB

Open AccessArticle

Study on the Aeromagnetic System between Fixed-Wing UAV and Unmanned Helicopter

by Yong-Zai Xi, Gui-Xiang Liao, Ning Lu, Yong-Bo Li and Shan Wu

Minerals 2023, 13(5), 700; https://doi.org/10.3390/min13050700 - 20 May 2023

Cited by 2 | Viewed by 1949

Abstract

Based on the CH-3 and WH-110A unmanned aerial vehicle (UAV) platforms, we independently developed aeromagnetic systems for fixed-wing UAVs (FUAV) and modified unmanned helicopters (MUH), respectively. These systems overcome key technological challenges in system integration, aeromagnetic compensation, and electromagnetic (EM) compatibility. We conducted [...] Read more.

Based on the CH-3 and WH-110A unmanned aerial vehicle (UAV) platforms, we independently developed aeromagnetic systems for fixed-wing UAVs (FUAV) and modified unmanned helicopters (MUH), respectively. These systems overcome key technological challenges in system integration, aeromagnetic compensation, and electromagnetic (EM) compatibility. We conducted a 1:100,000 aeromagnetic test using both systems in a tidal flat area in Jiangsu province, China. Both systems successfully completed 240 line km measurement lines and collected high-quality data with magnetic compensation accuracies of 0.01428 nT and 0.04690 nT, respectively. The dynamic noise was below 0.14 nT, accounting for 95.72% and 100% of the measurements. These results indicate that both systems offer high measurement accuracy, efficiency, low cost, convenience, and flexibility. We compared the two aeromagnetic systems based on their system parameters, integration modes, magnetic compensation methods and effects, and practical applications. By comprehensively analyzing their characteristics and application fields, we provide guidance for UAV-based aeromagnetic surveys in mineral exploration, basic geological survey and other related fields. And the FUAV and MUH aeromagnetic systems presented in this paper serve as a valuable reference for future research in this area. Full article

(This article belongs to the Special Issue Gravity and Magnetic Methods in Mineral Exploration)

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25 pages, 26221 KiB

Open AccessArticle

The Influence of Fluid-Exsolving Depth on Mineralization Quality: Evidence from Biotite and Zircon Mineralogy and Fluid Inclusions from the 460 Gaodi Porphyry Mo-Cu Deposit, NE China

by Jing Kan, Kezhang Qin, Le Wang, Kaixuan Hui and Ri Han

Minerals 2023, 13(5), 699; https://doi.org/10.3390/min13050699 - 20 May 2023

Viewed by 1134

Abstract

The recently discovered 460 Gaodi porphyry Mo-Cu deposit is a sub-economic deposit characterized by low Mo-Cu grades, dispersed mineralization, and separated Mo- and Cu-ore bodies. This study aims to elucidate the factors underlying this type of sub-economic mineralization. Electron-microprobe analyses of biotite from [...] Read more.

The recently discovered 460 Gaodi porphyry Mo-Cu deposit is a sub-economic deposit characterized by low Mo-Cu grades, dispersed mineralization, and separated Mo- and Cu-ore bodies. This study aims to elucidate the factors underlying this type of sub-economic mineralization. Electron-microprobe analyses of biotite from ore-related granite porphyry yielded Ti-in-biotite crystallization temperatures of 677–734 °C (an average of 719 °C) and biotite phenocryst crystallization depths of 6.0 to 12.9 km. LA-ICP-MS analyses of zircons from the same sample revealed average zircon Ce⁴⁺/Ce³⁺ ratios of 299.7 and elevated zircon lg(ƒO₂) ratios, with an average ΔFMQ of +6.6 ± 1.9. These discoveries suggest that the magma responsible for ore formation boasts a high degree of oxidation, yet also possesses a magma chamber located at a significant depth within the upper crust. This implies an extensive exsolving depth for fluids. Furthermore, our microthermometry analysis of fluid inclusions reveals that a portion of the fluid experiences considerable conductive cooling as it ascends along the conduit, owing to the depth of fluid exsolution. This process results in the ore fluids remaining in the liquid-only region without undergoing boiling, which is conducive to the enrichment of metals. We emphasize the fact that fluid-exsolving depth plays a critical role in determining the metal grades and economic value of a porphyry deposit by regulating the P-T evolution path of the ore fluids Full article

(This article belongs to the Special Issue Porphyry Metallogenic System: Genetic Mineralogy and Prospecting Mineralogy)

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18 pages, 6348 KiB

Open AccessFeature PaperArticle

Investigating the Amenability of a PGM-Bearing Ore to Coarse Particle Flotation

by Jestos Taguta, Mehdi Safari, Veruska Govender and Deshenthree Chetty

Minerals 2023, 13(5), 698; https://doi.org/10.3390/min13050698 - 20 May 2023

Cited by 2 | Viewed by 2446

Abstract

Coarse particle flotation (CPF) is one of the strategies employed to reduce energy consumption in mineral-processing circuits. Hydrofloat^TM (HF) technology has been successfully applied in the coarse flotation of industrial minerals and sulphide middlings. However, this technology has not yet been applied [...] Read more.

Coarse particle flotation (CPF) is one of the strategies employed to reduce energy consumption in mineral-processing circuits. Hydrofloat^TM (HF) technology has been successfully applied in the coarse flotation of industrial minerals and sulphide middlings. However, this technology has not yet been applied in platinum group minerals (PGMs)’ flotation. In this paper, the amenability of platinum group minerals to CPF was investigated. Extensive flotation testwork was conducted to optimise the hydrodynamic parameters, i.e., bed level, air and water flow rates, in the flotation of coarse PGM feed using Hydrofloat. Mineralogical analysis of the feed and selected flotation products was conducted to understand the reasons for the recovery and loss of the valuable minerals. The results showed that the HF separator could upgrade the PGM ore with particles as coarse as +106 − 300 µm. For the optimised test, a reasonable Pt, Pd and Au recovery of 84% was achieved at a grade of 10 g/t and 16.5% mass pull, despite the platinum group minerals being poorly liberated (4.5 vol% fully liberated). The results demonstrated that HF achieved high recovery efficiencies across the 150–300 microns size fraction. The HF was therefore able to substantially increase the upper particle size that can be successfully treated by flotation in PGM operations. It was found that an increase in bed height, water rate and air flow rate resulted in an increase in recovery to a maximum. A further increase in the hydrodynamic parameters resulted in a decline in recovery. Hydrofloat outperformed the conventional Denver flotation machine across the following size fractions: +106 − 150 µm, +150 − 212 µm, +212 − 250 µm and +250 − 300 µm. The practical implications of the findings on the modification of existing circuits and the design of novel flowsheets for the processing of PGM ores with less water and energy consumption are discussed. Full article

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

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27 pages, 5959 KiB

Open AccessArticle

Rapid Analysis of Muscovites on a Lithium Pegmatite Prospect by Handheld LIBS

by Russell S. Harmon, Michael A. Wise, Adam C. Curry, Joshua S. Mistele, Michael S. Mason and Zach Grimac

Minerals 2023, 13(5), 697; https://doi.org/10.3390/min13050697 - 19 May 2023

Cited by 3 | Viewed by 2449

Abstract

Laser-induced breakdown spectroscopy (LIBS) is a technology for compositional analysis that is particularly effective for light elements, particularly Li, which is a critical commodity for emerging green technologies. This study undertook analysis by handheld LIBS of muscovite from the drill core, outcrop, and [...] Read more.

Laser-induced breakdown spectroscopy (LIBS) is a technology for compositional analysis that is particularly effective for light elements, particularly Li, which is a critical commodity for emerging green technologies. This study undertook analysis by handheld LIBS of muscovite from the drill core, outcrop, and soil on the Carolina Lithium Prospect (CLP) in Gaston County, North Carolina (USA), which lies within the Carolina Tin-Spodumene Belt (CTSB). Abundances of the alkali elements Li, K, and Rb were determined for more than 130 muscovites from the Li-rich pegmatites to track the degree of pegmatite fractionation as a pathfinder for spodumene mineralization. Across the CTSB and including the CLP, muscovite Li contents vary over an order of magnitude, ranging from 0.04 to 0.74 wt. %, with their K/Rb ratios varying between 63 and 8, features that together document the highly evolved character of pegmatites within the CTSB district. On average, muscovite Li contents are greater in spodumene-bearing pegmatites at 0.21 ± 0.12 wt. % than for common quartz-feldspar pegmatites at 0.14 ± 0.08 wt. %. Although overlapping substantially in the middle portions of their distributions, muscovite K/Rb ratios are biased toward low values for spodumene-bearing pegmatites

(\bar{X}

= 21 ± 6) compared to those for quartz-feldspar pegmatites

(\bar{X}

= 33 ± 9). This study provides a framework for the use of LIBS analysis of muscovite in outcrop, drill core, and soil samples as an analytical tool for in-field and on-site geochemical analysis during Li pegmatite exploration and prospect evaluation. Full article

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

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19 pages, 2581 KiB

Open AccessArticle

Tracing Water–Rock–Gas Reactions in Shallow Productive Mud Chambers of Active Mud Volcanoes in the Caspian Sea Region (Azerbaijan)

by Aygun Bayramova, Orhan R. Abbasov, Adil A. Aliyev, Elnur E. Baloglanov, Franziska M. Stamm, Martin Dietzel and Andre Baldermann

Minerals 2023, 13(5), 696; https://doi.org/10.3390/min13050696 - 19 May 2023

Cited by 1 | Viewed by 1019

Abstract

We present geochemical and mineralogical datasets for five new mud volcanoes in continental Azerbaijan (Hamamdagh and Bendovan) and the adjacent Caspian Sea (Khara-Zire, Garasu and Sangi-Mughan). The fluid ejects have a Na–Cl-type composition and are generated by the mixing of evaporated Caspian seawater [...] Read more.

We present geochemical and mineralogical datasets for five new mud volcanoes in continental Azerbaijan (Hamamdagh and Bendovan) and the adjacent Caspian Sea (Khara-Zire, Garasu and Sangi-Mughan). The fluid ejects have a Na–Cl-type composition and are generated by the mixing of evaporated Caspian seawater and low- to high-salinity pore waters, as indicated by Br–B and Cl–B systematics and Na–K and SiO₂ geo-thermometers. The fluids contain high concentrations of As, Ba, Cu, Si, Li, Sr and Zn (60 to 26,300 ppm), which are caused by surface evaporation, pyrite oxidation, ion exchange reactions and hydrocarbon maturation in Oligocene-Miocene ‘Maykop’ shales. The solid ejects comprise liquid, oily and brecciated mud, mud/claystones and sandstones. The mud heterogeneity of the volcanoes is related to the geological age and different sedimentological strata of the host rocks that the mud volcanoes pass through during their ascent. All ejects show evidence of chemical alterations via water–rock–gas reactions, such as feldspar weathering, smectite illitization and the precipitation of Fe-(hydr)oxides, calcite, calcian dolomite, kaolinite and smectite. The studied localities have petrographic similarities to northern extending mud volcano systems located on Bahar and Zenbil islands, which suggests that mud volcanoes in the Caspian Sea region are sourced from giant shallow mud chambers (~1–4 km depth) located in Productive Series strata. Our results document the complex architecture of the South Caspian Basin—the most prolific hydrocarbon region in the world. Full article

(This article belongs to the Special Issue Mud Volcanism: Geological, Geochemical and Mineralogical Aspects of Event)

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41 pages, 4359 KiB

Open AccessReview

Biogeochemical Controls on Methane Generation: A Review on Indian Coal Resources

by Tushar Adsul, Santanu Ghosh, Susheel Kumar, Balram Tiwari, Subir Dutta and Atul Kumar Varma

Minerals 2023, 13(5), 695; https://doi.org/10.3390/min13050695 - 19 May 2023

Cited by 2 | Viewed by 2189

Abstract

Coal bed methane (CBM) extraction has astounding effects on the global energy budget. Since the earliest discoveries of CBM, this natural gas form has witnessed ever-increasing demands from the core sectors of the economy. CBM is an unconventional source of energy occurring naturally [...] Read more.

Coal bed methane (CBM) extraction has astounding effects on the global energy budget. Since the earliest discoveries of CBM, this natural gas form has witnessed ever-increasing demands from the core sectors of the economy. CBM is an unconventional source of energy occurring naturally within coal beds. The multiphase CBM generation during coal evolution commences with microbial diagenesis of the sedimentary organic matter during peatification, followed by early to mature thermogenic kerogen decomposition and post-coalification occurrences. Indeed, the origin of the CBM and, moreover, its economically valuable retention within coal seams is a function of various parameters. Several noticeable knowledge gaps include the controls of coal make-up and its physico-chemical position on the CBM generation and genetic link through fossil molecular and stable isotopic integration with the parent coal during its evolution. Therefore, this manuscript reviews the origin of CBM; the influences of coal properties and micropetrographic entities on CBM generation and storage; and its genetic molecular and stable isotope compositions in India and the world’s major coal reservoirs. Moreover, analyses of and outlooks on future development trends in the exploration, production, and application of coalbed methane are also addressed. Finally, as India has the fifth largest proven coal reserves, this brief review of the recent CBM discoveries and developments provides a plausible scope for microbially enhanced CBM production from these basins. Full article

(This article belongs to the Special Issue Micro-Mechanism and Characteristics of Coal Reservoirs)

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15 pages, 3861 KiB

Open AccessArticle

Exploratory Mapping of the Geothermal Anomalies in the Neoproterozoic Arabian Shield, Saudi Arabia, Using Magnetic Data

by Kamal Abdelrahman, Stephen E. Ekwok, Christian A. Ulem, Ahmed M. Eldosouky, Naif Al-Otaibi, Bashar Y. Hazaea, Saddam Ali Hazaea, Peter Andráš and Anthony E. Akpan

Minerals 2023, 13(5), 694; https://doi.org/10.3390/min13050694 - 19 May 2023

Cited by 5 | Viewed by 1752

Abstract

In this paper, certain areas of the Kingdom of Saudi Arabia (KSA) are assessed in order to map potential geothermal energy zones. To evaluate high-resolution aerial magnetic data, spectral depth analysis using a modified centroid approach was used. The calculated geothermal parameters were [...] Read more.

In this paper, certain areas of the Kingdom of Saudi Arabia (KSA) are assessed in order to map potential geothermal energy zones. To evaluate high-resolution aerial magnetic data, spectral depth analysis using a modified centroid approach was used. The calculated geothermal parameters were gridded in order to delineate the regions characterised by a shallow Curie point depth (CPD) and a high geothermal gradient (GG) as well as a high heat flow (HF). The CPD, GG and HF calculated from the analysed data varied in the ranges of 6.0–15.0 km, 40.0–100.0 °C/km and 90.0–270.0 mW/m², respectively. The obtained results show the concurrence of the positions of shallow CPD (<8.0 km), high GG (>83.5 °C/km) and high HF (>211.0 mW/m²). The geothermal systems that are oriented in the E–W direction are related to the Red Sea tectonics, the tectonic opening of the Red Sea/Gulf of the Suez Rift, hot subterranean anomalies and high enthalpy from radioactive granites. Likewise, the geologic structures (fractures and faults) related to the Red Sea tectonics serve as channels for the movement of hydrothermal fluids and the deposition of associated minerals. All in all, another geophysical study involving deep boreholes, and seismic, magnetotelluric, electromagnetic and geochemical data should be conducted to evaluate and estimate precisely the economic reserves of geothermal resources. Full article

(This article belongs to the Special Issue New Concept of Using Geophysical Data in Mineral Exploration, Depth Estimation and Structural Mapping)

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1 pages, 175 KiB

Open AccessCorrection

Correction: Seimetz et al. Geoelectric Signature of Gold Mineralization in the Alta Floresta Gold Province, Mato Grosso State, Brazil. Minerals 2023, 13, 203

by Eduardo Xavier Seimetz, Alexandre Santos Jeronimo da Costa, Welitom Rodrigues Borges, Marco Ianniruberto and Rafael Espindola Canata

Minerals 2023, 13(5), 693; https://doi.org/10.3390/min13050693 - 19 May 2023

Viewed by 450

Abstract

In our original publication [...] Full article

3 pages, 168 KiB

Open AccessEditorial

Editorial for the Special Issue “Heavy Metals in Marine and Lake Sediments”

by Liudmila L. Demina

Minerals 2023, 13(5), 692; https://doi.org/10.3390/min13050692 - 19 May 2023

Viewed by 719

Abstract

In recent decades, due to global warming and the continuing exploration in the search for mineral resources, the scientific attention paid to contamination problems has increased noticeably [...] Full article

(This article belongs to the Special Issue Heavy Metals in Marine and Lake Sediments)

20 pages, 5984 KiB

Open AccessArticle

Comparison of Granites from the Eastern and Western Districts of the Gejiu Ore District in South China: Implication for Petrogenesis and Tin Metallogeny

by Saijun Sun, Junjie Zhang, Shuang Li, Haobin Niu, Zhaojian Wu and Weidong Sun

Minerals 2023, 13(5), 691; https://doi.org/10.3390/min13050691 - 19 May 2023

Viewed by 1251

Abstract

Late Cretaceous granitoids are developed in the eastern and western districts of the Gejiu ore district, but tin deposits mainly occur in the eastern district, and the reasons for the difference in mineralization between the eastern and western districts are still controversial. Considering [...] Read more.

Late Cretaceous granitoids are developed in the eastern and western districts of the Gejiu ore district, but tin deposits mainly occur in the eastern district, and the reasons for the difference in mineralization between the eastern and western districts are still controversial. Considering the main factors controlling granite Sn fertility, the whole-rock geochemical characteristics of granites on both sides are compared. LA-ICP-MS zircon U-Pb analyses of the Gejiu granites yielded two age periods: the early phase from 79.2 to 83.3 Ma and the later phase from 73.8 to 75.6 Ma. The western district granites have higher zircon ε_Hf(t), CaO/Na₂O, Ba, and Sr concentrations and lower Rb/Sr ratios than the eastern district granites, indicating that the western district granites have more mantle-derived materials in the source than the eastern district granites. Results of oxygen fugacity show that the western granites have a higher oxygen fugacity condition. More depleted Ba, Sr, P, Eu and Ti characteristics with obviously negative Eu anomalies in the eastern granites also have high Rb/Sr ratios and low Nb/Ta and Zr/Hf ratios, indicating that the eastern granites experienced highly magmatic differentiation, attributed to high volatile F contents that can reduce the viscosity and solidus of magma. Combined with the differences in field observations and structural styles, on the whole, the western district granites have higher oxygen fugacities and lower F contents and magmatic differentiation than those in the eastern district granites, indicating that the western district granites are not conducive to mineralization. Full article

(This article belongs to the Special Issue Mineralization in Subduction Zone)

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25 pages, 14344 KiB

Open AccessArticle

Study the Mechanical Properties of Geopolymer under Different Curing Conditions

by Jinliang Liu, Xiaohui Shi, Guanhua Zhang and Linfei Li

Minerals 2023, 13(5), 690; https://doi.org/10.3390/min13050690 - 18 May 2023

Cited by 2 | Viewed by 1565

Abstract

The geopolymer is an environmentally friendly and high-performance material. Nowadays, how to improve the degree of the geopolymer’s reaction and enhance its mechanical properties has become a hot topic. This study used orthogonal tests to design the precursor mixing ratio, considering GGBS content [...] Read more.

The geopolymer is an environmentally friendly and high-performance material. Nowadays, how to improve the degree of the geopolymer’s reaction and enhance its mechanical properties has become a hot topic. This study used orthogonal tests to design the precursor mixing ratio, considering GGBS content (A), water/binder ratio (B), and alkaline activator modulus (C). The fly ash (FA) ground granulated blast furnace slag (GGBS)-based geopolymers were cured under two standard curing conditions: 40 °C under water and 40 °C in the oven. Then, the influence of these factors on the mechanical properties of geopolymers under different curing conditions was summarized. The contribution of each factor was ranked, which was used to find out the most sensitive factors affecting the mechanical properties. Taking the 7 days and 28 days of compressive strength and flexural strength of the geopolymer specimens as the evaluation criteria, the optimum ratio method for preparing geopolymers was obtained. Then, the prediction model of compressive strength under different curing conditions was established. SEM and XRD were used to analyze the microstructure and hydration products of the samples. The test results showed that the optimum ratio of FA-based geopolymers varied under different curing conditions. The GGBS content was the key factor in determining the mechanical properties. The heat curing condition was the best curing condition, the 28-day compressive strength could reach 76.3 MPa, and the 28-day flexural strength could reach 7.4 MPa. The prediction models established for compressive strength under different curing conditions had high accuracy. The specimens under the best curing conditions exhibited a dense internal microstructure and the presence of C-S-H gels, C-A-S-H gels, and N-A-S-H gels. Full article

(This article belongs to the Special Issue Alkali-Activated Binders)

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17 pages, 11563 KiB

Open AccessArticle

Study on the Sedimentary Environments and Its Implications of Shale Reservoirs for Permian Longtan Formation in the Southeast Sichuan Basin

by Yana Chen, Xuewen Shi, Hao Xu, Qian Cao, Xiangyang Pei, Wei Wu, Linqi Wang and Xue Yang

Minerals 2023, 13(5), 689; https://doi.org/10.3390/min13050689 - 18 May 2023

Cited by 1 | Viewed by 1005

Abstract

Marine–continental transitional shale is one of the most promising targets for shale gas exploration in the Lower Yangtze region. To investigate the sedimentary environments and the regularity of the enrichment of the Longtan shale, multiple techniques including core and thin-section observations, geochemical and [...] Read more.

Marine–continental transitional shale is one of the most promising targets for shale gas exploration in the Lower Yangtze region. To investigate the sedimentary environments and the regularity of the enrichment of the Longtan shale, multiple techniques including core and thin-section observations, geochemical and elemental analyses, X-ray diffraction, scanning electron microscopy (SEM), and low-pressure nitrogen adsorption (LPNA) were used to analyze the sedimentology, mineralogy, and pore structure of the Longtan shale. The core descriptions and thin-section observations showed that the Longtan shale was deposited in marine–delta transitional environments including delta-front, shore swamp, mixed tidal flat and shallow shelf environments. The Sr/Cu, V/Cr, CIA, EF (Mo), EF (U), and other major and trace element results indicated warm and moist climates and water-reducing conditions in the Longtan period. Both the climate and water conditions were favorable for organic matter production and preservation. The geochemical results showed that the Longtan shale was in the overmature stage (Ro values ranging from 2.4% to 3.57%) and that the average total organic carbon (TOC) content was 5.76%. The pore system of the Longtan shale consisted of inorganic pores with a small number of organic pores and microfractures. The porosity and specific surface area were mainly affected by the TOC and clay mineral contents. An effective combination of brittle mineral particles, organic matter, and clay minerals provided the necessary conditions for pore preservation. The organic pores, intergranular pores in clay minerals, and brittle mineral pores formed the main network system for the Longtan shale. In summary, the lithological combinations, organic geochemistry, and pore structure system were all affected by the sedimentary environments. Full article

(This article belongs to the Topic Hydrocarbon Generation and Accumulation in Unconventional Shale Reservoir: Up-to-Date Advances in Theory, Experiment, Method and Application, Volume II)
(This article belongs to the Section Mineral Exploration Methods and Applications)

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12 pages, 1648 KiB

Open AccessFeature PaperArticle

Tree Rings Record of Long-Term Atmospheric Hg Pollution in the Monte Amiata Mining District (Central Italy): Lessons from the Past for a Better Future

by Silvia Fornasaro, Francesco Ciani, Alessia Nannoni, Guia Morelli, Valentina Rimondi, Pierfranco Lattanzi, Claudia Cocozza, Marco Fioravanti and Pilario Costagliola

Minerals 2023, 13(5), 688; https://doi.org/10.3390/min13050688 - 18 May 2023

Cited by 3 | Viewed by 1562

Abstract

Trees may represent useful long-term monitors of historical trends of atmospheric pollution due to the trace elements stored along the tree rings caused by modifications in the environment during a tree’s life. Chestnut (Castanea sativa Mill.) tree trunk sections were used to [...] Read more.

Trees may represent useful long-term monitors of historical trends of atmospheric pollution due to the trace elements stored along the tree rings caused by modifications in the environment during a tree’s life. Chestnut (Castanea sativa Mill.) tree trunk sections were used to document the yearly evolution of atmospheric Hg in the world-class mining district of Monte Amiata (MAMD; Central Italy) and were exploited until 1982. An additional source of Hg emissions in the area have been the active geothermal power plants. A marked decrease (from >200 µg/kg to <100 µg/kg) in Hg contents in heartwood tree rings is recorded, likely because of mine closure; the average contents (tens of µg/kg) in recent years remain higher than in a reference area ~150 km away from the district (average 4.6 µg/kg). Chestnut barks, recording present-day Hg pollution, systematically show higher Hg concentrations than sapwood (up to 394 µg/kg in the mining area). This study shows that tree rings may be a good record of the atmospheric Hg changes in areas affected by mining activity and geothermal plants and can be used as a low-cost biomonitoring method for impact minimization and optimal resource and land management. Full article

(This article belongs to the Special Issue Sustainable Mining as the Key for the Ecological Transition: Current Trends and Future Perspectives)

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31 pages, 33833 KiB

Open AccessArticle

Mineralogy, Geochemistry, and Genesis of Agates from Chihuahua, Northern Mexico

by Maximilian Mrozik, Jens Götze, Yuanming Pan and Robert Möckel

Minerals 2023, 13(5), 687; https://doi.org/10.3390/min13050687 - 18 May 2023

Viewed by 2231

Abstract

The present study aimed to investigate the genesis and characteristics of some of the world-famous agate deposits in the state of Chihuahua, Mexico (Rancho Coyamito, Ojo Laguna, Moctezuma, Huevos del Diablo, Agua Nueva). Geochemical and textural studies of host rocks showed that all [...] Read more.

The present study aimed to investigate the genesis and characteristics of some of the world-famous agate deposits in the state of Chihuahua, Mexico (Rancho Coyamito, Ojo Laguna, Moctezuma, Huevos del Diablo, Agua Nueva). Geochemical and textural studies of host rocks showed that all the studied deposits are related to the same rock type within the geological unit of Rancho el Agate andesite, a quartz-free latite that shows clear indications of magma mixing. As a result of their large-scale distribution and various differentiation processes, as well as transport separation, different textures and local chemical differences between rocks of different localities can be observed. These differences have also influenced the properties of SiO₂ mineralization in the rocks. The mixing of near-surface fluids from rock alterations with magmatic hydrothermal solutions led to the accumulation of various elements in the SiO₂ matrix of the agates, which were, on the one hand, mobilized during secondary rock alteration (Fe, U, Ca, K, Al, Si) and, on the other hand, transported with magmatic fluids (Zn, Sb, Si, Zr, Cr). Different generations of chalcedony indicate a multi-stage formation as well as multiple cycles of filling the cavities with fluids. The hydrothermal fluids are presumably related to the residual solutions of a rhyolitic volcanism, which followed the latitic extrusions in the area and probably caused the formation of polymetallic ore deposits in the Chihuahua area. The enrichment of highly immobile elements indicates the involvement of volatile fluids in the agate formation. The vivid colors of the agates are almost exclusively due to various mineral inclusions, which consist mainly of iron compounds. Full article

(This article belongs to the Special Issue Mineralogy, Geochemistry, and Origin of Agate: An Ongoing Challenge)

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16 pages, 5566 KiB

Open AccessFeature PaperArticle

Silica Polymorphs Formation in the Jänisjärvi Impact Structure: Tridymite, Cristobalite, Quartz, Trace Stishovite and Coesite

by Daria A. Zamiatina, Dmitry A. Zamyatin, Georgii B. Mikhalevskii and Nikolai S. Chebikin

Minerals 2023, 13(5), 686; https://doi.org/10.3390/min13050686 - 17 May 2023

Viewed by 1385

Abstract

The study of silica polymorphs in impactites is important for determining the pressure and temperature of impact rock formation. Silica modifications in impact melt rocks of the Janisjärvi impact structure (Karelia, Russia) are presented by tridymite, cristobalite, quartz, trace stishovite and coesite. Silica [...] Read more.

The study of silica polymorphs in impactites is important for determining the pressure and temperature of impact rock formation. Silica modifications in impact melt rocks of the Janisjärvi impact structure (Karelia, Russia) are presented by tridymite, cristobalite, quartz, trace stishovite and coesite. Silica modifications were characterized and studied by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and Raman and cathodoluminescent spectroscopy. Investigations were carried out in order to clarify polymorphs formation mechanisms and search for signs of the transition of certain structural modifications to others. For the first time, a description of tridymite with a ballen-like texture from impact melt rock is given. A sequence of silica modification and textural transformation in impact rocks after the impact event is suggested. We conclude that the pressure of 40 GPa and a temperature of more than 900 °C were achieved in the impact structure. Full article

(This article belongs to the Special Issue Geochronology, Crystallography and Phase Transition in Shocked Minerals)

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25 pages, 8499 KiB

Open AccessArticle

Archean Crustal Evolution of the Alxa Block, Western North China Craton: Constraints from Zircon U-Pb Ages and the Hf Isotopic Composition

by Pengfei Niu, Junfeng Qu, Jin Zhang, Beihang Zhang and Heng Zhao

Minerals 2023, 13(5), 685; https://doi.org/10.3390/min13050685 - 17 May 2023

Viewed by 1153

Abstract

The Alxa Block is an important component of the North China Craton, but its metamorphic basement has been poorly studied, which hampers the understanding of the Alxa Block and the North China Craton. In this study, we conducted geochronological and geochemical studies on [...] Read more.

The Alxa Block is an important component of the North China Craton, but its metamorphic basement has been poorly studied, which hampers the understanding of the Alxa Block and the North China Craton. In this study, we conducted geochronological and geochemical studies on three TTG (tonalite–trondhjemite–granodiorite) gneisses and one granitic gneiss exposed in the Langshan area of the eastern Alxa Block to investigate their crustal evolution. The zircon U-Pb dating results revealed that the protoliths of the TTG and granitic gneisses were formed at 2836 ± 20 Ma, 2491 ± 18 Ma, 2540 ± 38 Ma, and 2763 ± 42 Ma, respectively, and were overprinted by middle–late Paleoproterozoic metamorphism (1962–1721 Ma). All gneiss samples had high Sr/Y ratios (41–274) and intermediate Mg^# values (44.97–55.78), with negative Nb, Ta, and Ti anomalies and moderately to strongly fractionated REE patterns ((La/Yb)_N = 10.6–107.1), slight Sr enrichment, and positive Eu anomalies, displaying features of typical high-SiO₂ adakites and Archean TTGs. The magmatic zircons from the 2.84 Ga and 2.49 Ga TTG rocks had low ε_Hf(t) values of −1.9–1.7, and −3.83–2.12 with two-stage model ages (T_DMC) of 3.24–3.11 Ga and 3.10–3.01 Ga, respectively, whereas those from the 2.54 Ga TTG rock exhibited ε_Hf(t) values ranging from −1.1 to 3.46 and T_DMC from 3.0 Ga to 2.83 Ga, suggesting that the crustal materials of the basement rocks in the eastern Alxa Block were initially extracted from the depleted mantle during the late Paleoarchean to Mesoarchean era and were reworked in the late Mesoarchean and late Neoarchean era. By contrast, the Alxa Block probably had a relative younger crustal evolutionary history (<3.24 Ga) than the main North China (<3.88 Ga), Tarim (<3.9 Ga), and Yangtze (<3.8 Ga) Cratons and likely had a unique crustal evolutionary history before the early Paleoproterozoic era. Full article

(This article belongs to the Special Issue Formation and Evolution of the Continental Crust in North China Craton during Precambrian)

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22 pages, 8773 KiB

Open AccessArticle

Justification for Criteria for Evaluating Activation and Destruction Processes of Complex Ores

by Tatiana Aleksandrova, Nadezhda Nikolaeva, Anastasia Afanasova, Artyem Romashev and Valentin Kuznetsov

Minerals 2023, 13(5), 684; https://doi.org/10.3390/min13050684 - 17 May 2023

Cited by 2 | Viewed by 967

Abstract

The mining industry is faced with the problem of depletion of reserves of easily beneficiated minerals containing valuable metals. The characteristic features of the ores involved in processing are fine dissemination; low content of valuable components; and similar physical, chemical, surface, and technological [...] Read more.

The mining industry is faced with the problem of depletion of reserves of easily beneficiated minerals containing valuable metals. The characteristic features of the ores involved in processing are fine dissemination; low content of valuable components; and similar physical, chemical, surface, and technological properties of minerals, among others. Under such conditions, increasing the efficiency of mineral processing becomes of primary importance. Creating highly efficient, environmentally safe technologies on the basis of deep study of the material, chemical, and mineralogical composition, as well as using and developing methods and techniques for testing mineral materials at successive stages of raw material transformation, enable to solve such problems. Criteria for assessing the flow of technological processes are presented in the article. A complex criterion is substantiated and proposed for quantitative assessment of the degree of physical and energy impact at the stages of ore preparation and flotation enrichment of mineral raw materials. The criterion is calculated on the basis of activation energy data calculated by differential and integral kinetic methods. In addition, an empirical indicator was introduced into the complex criterion, which allows increasing the accuracy of the calculated criterion. This criterion not only allows to estimate the degree of influence from the position of averaged estimation on the full interval of degrees of transformation from 0 to 1, but also gives the possibility to consider the required number of degrees of transformation; for example, if it is necessary to make estimations on narrow temperature intervals. The calculation of empirical parameters for the obtained criterion is carried out before and after the application of physical–energetic methods of influence using thermal analysis. Full article

(This article belongs to the Special Issue Valuable Metals Recovery by Mineral Processing and Hydrometallurgy)

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12 pages, 3000 KiB

Open AccessArticle

Morphological and Physicochemical Properties of Macrocrystalline Talc from Argentine

by Silvia E. Barbosa and Luciana A. Castillo

Minerals 2023, 13(5), 683; https://doi.org/10.3390/min13050683 - 17 May 2023

Viewed by 1386

Abstract

A detailed petrographical, mineralogical, morphological, geochemical and physicochemical characterization of talc from an Argentinean ore is presented. This deposit is located in the San Juan province at the foothills of the Andes. Characterization was performed on rock and milled talc using different techniques [...] Read more.

A detailed petrographical, mineralogical, morphological, geochemical and physicochemical characterization of talc from an Argentinean ore is presented. This deposit is located in the San Juan province at the foothills of the Andes. Characterization was performed on rock and milled talc using different techniques including polarized light microscopy, transmission electron and scanning microscopy with energy dispersive spectroscopy (SEM/EDX), chemical analyses, X-ray diffraction (XRD), X-ray fluorescence, Fourier transform infrared spectroscopy (FTIR), particle size determination by laser diffraction, thermogravimetry analysis, and colorimetry. A mineral sample contains approximately 80 wt% talc. Associated minerals such as carbonates as veins and chlorite interlaminated with talc were detected. Carbonates are calcite, dolomite and magnesite, as was corroborated by FTIR. Morphology and crystallinity were assessed by XRD data, obtaining a morphological index of 0.79 which indicates the macrocrystalline character. Crystalline habits of associated minerals were recognized by SEM, detecting their constitutive elements by EDX. Talc color parameters are L* = 82.76, a* = −1.50, and b* = 5.38. The slight yellowing could be attributed to chlorite or traces of Fe oxides. Although the whiteness index (62.12) impedes its commercialization as a high-priced mineral, this kind of talc can be used as an additive for polymers, since it would offer a high reinforcing effect (improvement of mechanical properties). Full article

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

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15 pages, 2484 KiB

Open AccessArticle

Effect of Cation Chloride Concentration on the Dissolution Rates of Basaltic Glass and Labradorite: Application to Subsurface Carbon Storage

by Kiflom G. Mesfin, Domenik Wolff-Boenisch, Sigurdur R. Gislason and Eric H. Oelkers

Minerals 2023, 13(5), 682; https://doi.org/10.3390/min13050682 - 17 May 2023

Cited by 2 | Viewed by 1173

Abstract

The steady-state dissolution rates of basaltic glass and labradorite were measured in the presence of 10 to 700 × 10⁻³ mol·kg⁻¹ aqueous NaCl, KCl, CaCl₂, and MgCl₂ at 25 °C. All rates were measured in mixed flow reactors, [...] Read more.

The steady-state dissolution rates of basaltic glass and labradorite were measured in the presence of 10 to 700 × 10⁻³ mol·kg⁻¹ aqueous NaCl, KCl, CaCl₂, and MgCl₂ at 25 °C. All rates were measured in mixed flow reactors, and at pH~3.6 by the addition of HCl to the reactive fluids. The steady-state basaltic glass dissolution rates, based on Si release, increased by ~0.3 log units in the presence of 10⁻³ mol·kg⁻¹ of either CaCl₂ or MgCl₂ compared to their rates in 10⁻³ mol·kg⁻¹ of NaCl or KCl. In contrast, the steady-state dissolution rates of labradorite decreased by ~0.4 log units in the presence of 10⁻³ mol·kg⁻¹ of either CaCl₂ or MgCl₂ compared to their rates in 10⁻³ mol·kg⁻¹ of NaCl or KCl. These contrasting behaviours likely reflect the varying effects of these cations on the stability of rate controlling Si-rich activated complexes on the surface of the dissolving solids. On average, the Si release rates of these solids are similar to each other and increase slightly with increasing ionic strength. As the pH of water charged with 10 to 30 bars CO₂ is ~3.6, the results of this study indicate that both basaltic glass and labradorite dissolution will likely be effective at increasing the pH and adding Ca to the aqueous phase in saline fluids. This observation supports potential efforts to store carbon through its mineralization in saline aquifers containing Ca-bearing feldspar and in submarine basalts. Full article

(This article belongs to the Special Issue Advances in Mineral Carbonation)

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28 pages, 24421 KiB

Open AccessArticle

Paleoproterozoic East Pana Layered Intrusion (Kola Peninsula, Russia): Geological Structure, Petrography, Geochemistry and Cu-Ni-PGE Mineralization

by Pavel Pripachkin, Tatiana Rundkvist and Nikolay Groshev

Minerals 2023, 13(5), 681; https://doi.org/10.3390/min13050681 - 16 May 2023

Cited by 2 | Viewed by 1114

Abstract

The East Pana intrusion is a part of the Paleoproterozoic Fedorova–Pana complex (FPC), which belongs to the group of Fennoscandian layered mafic–ultramafic massifs. This article discusses the magmatic stratification of the East Pana intrusion, as well as Cu-Ni and platinum-group elements (PGE) mineralization [...] Read more.

The East Pana intrusion is a part of the Paleoproterozoic Fedorova–Pana complex (FPC), which belongs to the group of Fennoscandian layered mafic–ultramafic massifs. This article discusses the magmatic stratification of the East Pana intrusion, as well as Cu-Ni and platinum-group elements (PGE) mineralization (PGE zones A, B and C) in its various parts with a total length of more than 20 km, including the East Chuarvy PGE deposit. Based on the whole-rock data on the distribution of major, trace, and ore-forming elements, it is assumed that PGE zone A belongs to the main ore–magmatic system of the FPC, while PGE zones B and C belong to the minor ore–magmatic systems. At the same time, additional magmatic injection played an important role in the formation of economic Cu-Ni-PGE mineralization (PGE zone B), characterized by high PGE concentrations and moderate palladium enrichment. On the normalized distribution spectra of trace elements, the crystallization products of this injection (Gabbronorite Zone 2) have a positive Zr-Hf anomaly, which distinguishes it from host rocks with an anomaly of the opposite sign (Gabbronorite Zone 1, Gabbro Zone). It is assumed that this portion of magma was intruded as a sill of crystal mush, the fractionation of which at depth led to its enrichment with residual liquid. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: "Critical and Strategic Minerals")

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26 pages, 25738 KiB

Open AccessArticle

A Comparison between the Standard Heterogeneity Test and the Simplified Segregation Free Analysis for Sampling Protocol Optimisation

by Ana Carolina Chieregati, Gabriela Cardoso Prado, Flavia L. Fernandes, Fernando L. S. P. Villanova and Simon C. Dominy

Minerals 2023, 13(5), 680; https://doi.org/10.3390/min13050680 - 16 May 2023

Cited by 1 | Viewed by 1107

Abstract

Estimating the heterogeneity of base and precious metal mineralisation is a great challenge for mining engineers and geologists who undertake resource evaluation, grade control and reconciliation. The calculation of the minimum broken sample mass to represent a given lot of mineralisation at a [...] Read more.

Estimating the heterogeneity of base and precious metal mineralisation is a great challenge for mining engineers and geologists who undertake resource evaluation, grade control and reconciliation. The calculation of the minimum broken sample mass to represent a given lot of mineralisation at a given comminution size is based on the estimation of IH_L, the constant factor of constitution heterogeneity. IH_L can be derived by different heterogeneity testwork or calibration approaches. Three methodologies are well known in the mining industry: the standard heterogeneity test, the segregation free analysis, and the sampling tree experiment or duplicate sample analysis. However, the methodologies often show different results, especially when it comes to gold. These differences are due to many reasons. Assuming the variances added by sample preparation and analysis to be equivalent for all tests, the reasons for the differences may include the nugget effect (particularly the presence of coarse gold), the segregation effect and the procedure of collecting/splitting the samples when performing the tests. This paper analyses and compares two heterogeneity tests: the original heterogeneity test and the simplified segregation free analysis, both performed on mineralisation from different Brazilian operations. The results show clear differences between the tests, highlighting the complexity of estimating the heterogeneity of mineral deposits. The study reports the importance of using proper methodologies for constitution heterogeneity estimation so that minimum sample masses and relative standard deviations of the fundamental sampling error can be relied upon. It also provides recommendations for practitioners on the application of testwork/calibration studies. Full article

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

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