Minerals

16 pages, 10421 KiB

Open AccessArticle

Differential Characteristics of Conjugate Strike-Slip Faults and Their Controls on Fracture-Cave Reservoirs in the Halahatang Area of the Northern Tarim Basin, NW China

by Shenglei Wang, Lixin Chen, Zhou Su, Hongqi Dong, Bingshan Ma, Bin Zhao, Zhendong Lu and Meng Zhang

Minerals 2024, 14(7), 688; https://doi.org/10.3390/min14070688 (registering DOI) - 30 Jun 2024

Abstract

The X-type strike-slip fault system and weathering crust karst fracture-cave and channel reservoirs were developed in the Halahatang area of the northern Tarim Basin. However, the relationship between the reservoir and the strike-slip fault remains controversial. Based on the core data, and taking [...] Read more.

The X-type strike-slip fault system and weathering crust karst fracture-cave and channel reservoirs were developed in the Halahatang area of the northern Tarim Basin. However, the relationship between the reservoir and the strike-slip fault remains controversial. Based on the core data, and taking an NE-striking strike-slip fault as an example, this paper dissects the karst reservoir from wells along the strike-slip fault damage zone and analyzes the control of scales, properties, and segmentation styles of strike-slip faults on karst reservoirs. The results show that (1) the scale of the strike-slip fault controls the distribution of the reservoir—the wider the fault damage zone, the wider the fracture-cave reservoirs; (2) the transtensional segments of the strike-slip fault are more likely to produce karstification, and the buried-hill area and the interbedded area are controlled by different hydrodynamic conditions to form different types of karst reservoirs; (3) six different parts of the strike-slip fault are conducive to the formation scale of fault fracture zones. This research provides new insight into recognizing karst reservoirs within strike-slip fault damage zones, which can be further applied to predict karst reservoirs controlled by strike-slip faults. Full article

(This article belongs to the Special Issue Deformation, Diagenesis, and Reservoir in Fault Damage Zone)

21 pages, 4408 KiB

Open AccessArticle

Genesis of the Ke’eryin Two-Mica Monzogranite in the Ke’eryin Pegmatite-Type Lithium Ore Field, Songpan–Garze Orogenic Belt: Evidence from Lithium Isotopes

by **n Li, Hongzhang Dai, Shanbao Liu, Denghong Wang, Fan Huang, **hua Qin, Yan Sun and Haiyang Zhu

Minerals 2024, 14(7), 687; https://doi.org/10.3390/min14070687 (registering DOI) - 29 Jun 2024

Abstract

Abstract: Previous studies on the Ke’eryin pegmatite-type lithium ore field in the Songpan–Ganzi Orogenic Belt have explored the characteristics of the parent rock but have not precisely determined its magma source area. This uncertainty limits our understanding of the regularity of lithium ore [...] Read more.

Abstract: Previous studies on the Ke’eryin pegmatite-type lithium ore field in the Songpan–Ganzi Orogenic Belt have explored the characteristics of the parent rock but have not precisely determined its magma source area. This uncertainty limits our understanding of the regularity of lithium ore formation in this region. In this study, to address the issue of the precise source area of the parent rock of lithium mineralization, a detailed analysis of the Li isotope composition of the ore-forming parent rock (Ke’eryin two-mica monzogranite) and its potential source rocks (Triassic **kang Group metamorphic rocks) was conducted. The δ⁷Li values of the Ke’eryin two-mica monzogranite, **kang Group metasandstone, and **kang Group mica schist are −3.3–−0.7‰ (average: −1.43‰), +0.1–+6.9‰ (average: +3.83‰), and −9.1–0‰ (average: −5.00‰), respectively. The Li isotopic composition of the Ke’eryin two-mica monzogranite is notably different from the metasandstone and aligns more closely with the mica schist, suggesting that the mica schist is its primary source rock. The heavy Li isotopic composition of the two-mica monzogranite compared to the mica schist may have resulted from the separation of the peritectic garnet into the residual phase during the biotite dehydration melting process. Moreover, the low-temperature weathering of the source rocks may have been the main factor leading to the lighter lithium isotope composition of the **kang Group mica schist compared to the metasandstone. Further analysis suggests that continental crust weathering and crustal folding and thickening play crucial roles in the enrichment of lithium during multi-cycle orogenies. Full article

(This article belongs to the Special Issue Metallogenic Regularity and Metallographic Prediction of Strategic Deposits)

45 pages, 4063 KiB

Open AccessReview

Three-Dimensional Geological Modelling in Earth Science Research: An In-Depth Review and Perspective Analysis

by **aoqin Cao, Ziming Liu, Chenlin Hu, **aolong Song, Jonathan Atuquaye Quaye and Ning Lu

Minerals 2024, 14(7), 686; https://doi.org/10.3390/min14070686 (registering DOI) - 29 Jun 2024

Abstract

This study examines the development trajectory and current trends of three-dimensional (3D) geological modelling. In recent years, due to the rising global energy demand and the increasing frequency of regional geological disasters, significant progress has been made in this field. The purpose of [...] Read more.

This study examines the development trajectory and current trends of three-dimensional (3D) geological modelling. In recent years, due to the rising global energy demand and the increasing frequency of regional geological disasters, significant progress has been made in this field. The purpose of this study is to clarify the potential complexity of 3D geological modelling, identify persistent challenges, and propose potential avenues for improvement. The main objectives include simplifying the modelling process, improving model accuracy, integrating different data sources, and quantitatively evaluating model parameters. This study integrates global research in this field, focusing on the latest breakthroughs and applications in mineral exploration, engineering geology, geological disaster assessment, and military geosciences. For example, unmanned aerial vehicle (UAV) tilt photography technology, multisource data fusion, 3D geological modelling method based on machine learning, etc. By identifying areas for improvement and making recommendations, this work aims to provide valuable insights to guide the future development of geological modelling toward a more comprehensive and accurate “Transparent Earth”. This review underscores the global applications of 3D geological modelling, highlighting its crucial role across various sectors such as mineral exploration, the oil and gas industry, urban planning, geological hazard assessment, and geoscientific research. The review emphasizes the sector-specific importance of this technology in enhancing modelling accuracy and efficiency, optimizing resource management, driving technological innovation, and improving disaster response capabilities. These insights provide a comprehensive understanding of how 3D geological modelling can significantly impact and benefit multiple industries worldwide. Full article

(This article belongs to the Special Issue 3D/4D Geological Modeling for Mineral Exploration, 2nd Edition)

30 pages, 3040 KiB

Open AccessArticle

The Tepsi Ultrabasic Intrusion, the Northern Part of the Lapland–Belomorian Belt, Kola Peninsula, Russia

by Andrei Y. Barkov, Andrey A. Nikiforov, Robert F. Martin, Sergey A. Silyanov and Boris M. Lobastov

Minerals 2024, 14(7), 685; https://doi.org/10.3390/min14070685 (registering DOI) - 29 Jun 2024

Abstract

The Tepsi ultrabasic body is located in the northeastern Fennoscandian Shield close to the junction of the Serpentinite Belt–Tulppio Belt (SB–TB) with suites of the Lapland–Belomorian Belt (LBB) of Paleoproterozoic age. The body is a deformed laccolith that has tectonic contacts with Archean [...] Read more.

The Tepsi ultrabasic body is located in the northeastern Fennoscandian Shield close to the junction of the Serpentinite Belt–Tulppio Belt (SB–TB) with suites of the Lapland–Belomorian Belt (LBB) of Paleoproterozoic age. The body is a deformed laccolith that has tectonic contacts with Archean rocks. Its primary textures and magmatic parageneses are widely preserved. Fine-grained olivine varies continuously from Fo_90.5 to Fo_65.4. The whole-rock variations in MgO, Fe₂O₃, SiO₂, and other geochemical data are also indicative of a significant extent of differentiation. Compositional variations were examined in the grains of calcic and Mg-Fe amphiboles, clinochlore, micas, plagioclase, members of the chromite–magnetite series, ilmenite, apatite, pentlandite, and a number of other minor mineral species. Low-sulfide disseminated Ni-Cu-Co mineralization occurred sporadically, with the presence of species enriched in As or Bi, submicrometric grains rich in Pt and Ir, or diffuse zones in pentlandite enriched in (Pd + Bi). We recognize two series: the pentlandite series (up to 2.5–3 wt.% Co) and the cobaltpentlandite series (~1 to ~8 apfu Co). The latter accompanied serpentinization. The two series display differences in their substitutions: Ni ↔ Fe and Co → (Ni + Fe), respectively. Relative enrichments in H₂O, Cl, and F, observed in grains of apatite (plus high contents of Cl in hibbingite or parahibbingite), point to the abundance of volatiles accumulated during differentiation. We provide the first documentation of scheelite grains in ultrabasic rocks, found in evolved olivine-rich rocks (Fo_77–72). We also describe unusual occurrences of hypermagnesian clinopyroxene associated with tremolite and serpentine. Abundant clusters of crystallites of diopside display a microspinifex texture. They likely predated serpentinization and formed due to rapid crystallization in a differentiated portion of a supercooled oxidized melt or, less likely, fluid, after bulk crystallization of the olivine. We infer that the laccolithic Tepsi body crystallized rapidly, in a shallow setting, and could thus not form megacycles in a layered series or produce a well-organized structure. Our findings point to the existence of elevated PGE-Au-Ag potential in numerous ultrabasic–basic complexes of the SB–TB–LBB megastructure. Full article

(This article belongs to the Special Issue From Mantle to Market: Platinum Group Elements and Minerals and Their Geological Significance)

17 pages, 16927 KiB

Open AccessArticle

Distribution and Enrichment Mechanisms of Selenium in Stibnite from the Xujiashan Sb Deposit, Hubei Province, China

by Yuhang Liu, Dazhao Wang, Ruolong Huang, Guanzhi Wang, Wei Wan and Yu Kong

Minerals 2024, 14(7), 684; https://doi.org/10.3390/min14070684 (registering DOI) - 29 Jun 2024

Abstract

The Xujiashan Sb deposit located at the Mufushan fold thrust belt of the Yangtze block is one of the most important Sb deposits in this district. Stibnite in this deposit contains high and various contents of Se, but research on the distribution and [...] Read more.

The Xujiashan Sb deposit located at the Mufushan fold thrust belt of the Yangtze block is one of the most important Sb deposits in this district. Stibnite in this deposit contains high and various contents of Se, but research on the distribution and enrichment of Se in stibnite remains limited. This paper conducts geochemical composition, C-H-O isotopic composition, and scanning electron microscopy morphology of the Xujiashan deposit to discuss the sources of ore-forming materials and fluid, as well as the distribution and enrichment mechanisms of selenium in stibnite. The results showed that the ores have trace element compositions comparable with the wall rocks, and Sb and Se contents are significantly higher than the average carbonate rocks. The δ¹³C_PDB values of calcite and quartz range from −12.8‰ to 5.5‰, the δ¹⁸O_SMOW values range from 20.4‰ to 24‰, and the δD_V-SMOW values range from −57.8‰ to −86.9‰. Trace element and isotope compositions indicate that the ore-forming materials were mainly derived from the wall rocks (sedimentary–metamorphic rocks) that S, Se, and Sb dissolved during fluid–rock interactions. The ore-forming fluids were metamorphic water produced by metamorphism, which had experienced multistage mixing with meteoric water and organic-rich fluids. Selenium substitutes for sulfur in the stibnite crystal lattice, causing rhythmically distributed Se contents in stibnite, which resulted from multistage physicochemical changes in ore-forming fluids during crystallization. The varied patterns of Se contents are the result of different cross-sections of the stibnite. Full article

(This article belongs to the Special Issue Selenium, Tellurium and Precious Metal Mineralogy)

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15 pages, 3157 KiB

Open AccessArticle

Spectroscopic Identification of Mineral Pigments in White Decorated Prehistoric Pottery from Bulgaria

by Vani Tankova, Victoria Atanassova, Valentin Mihailov and Angelina Pirovska

Minerals 2024, 14(7), 683; https://doi.org/10.3390/min14070683 (registering DOI) - 29 Jun 2024

Abstract

In the prehistoric period on the Balkan Peninsula, the technology of white decoration underwent a drastic change. At the beginning of the Neolithic white pigment was applied as paint on a polished surface. At the end of the epoch, white paste was inlaid [...] Read more.

In the prehistoric period on the Balkan Peninsula, the technology of white decoration underwent a drastic change. At the beginning of the Neolithic white pigment was applied as paint on a polished surface. At the end of the epoch, white paste was inlaid in incised channels on the surfaces of vessels. This study is focused on the identification of mineral pigments used for white decoration of Neolithic and Chalcolithic pottery from the territory of Bulgaria. The aim of this work is to answer the question of whether the composition of the white pigment varies according to the technique of decoration (paint and inlay). A set of 41 pottery fragments from 11 archaeological sites on the territory of Bulgaria was analyzed utilizing two spectroscopic techniques: laser-induced breakdown spectroscopy (LIBS) and Fourier-transform infrared spectroscopy (FTIR). Additionally, the experimental data from the LIBS were statistically treated with the multivariate technique, principal component analysis (PCA). The results from the spectral analysis indicated that the main constituent in the white decorated sherds is calcite in various combinations with carrier materials like quartz, feldspars, and metal oxides. The statistical analysis revealed that the primal constituent in the inlaid sherds is calcite while in the painted part, the carrier material is dominant. In some particular sherds, gypsum, hydroxylapatite, kaolinite, and aragonite were also detected. Full article

(This article belongs to the Special Issue Mineralogical Approaches to Archaeological and Cultural Heritage Materials)

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14 pages, 8121 KiB

Open AccessArticle

Biogenic Calcium Carbonate: Phase Conversion in Aqueous Suspensions

by Brian Espinosa-Acosta, Jake J. Breen, Meghan Burchell and Kristin M. Poduska

Minerals 2024, 14(7), 682; https://doi.org/10.3390/min14070682 (registering DOI) - 29 Jun 2024

Abstract

Powdered biogenic calcium carbonate from butter clams shows variations in its tendency to convert from aragonite to calcite when suspended in water, depending on whether the suspension has additional calcite or not. Our investigations treat these biogenic samples as complex hierarchical materials, considering [...] Read more.

Powdered biogenic calcium carbonate from butter clams shows variations in its tendency to convert from aragonite to calcite when suspended in water, depending on whether the suspension has additional calcite or not. Our investigations treat these biogenic samples as complex hierarchical materials, considering both their mineral and organic components. We assess the mineral composition from Attenuated Total Reflection Fourier Transform Infrared spectroscopy peak shifts, as well as quantitative assessments of lattice constant refinements (powder X-ray diffraction). To isolate the mineral portions, we compare results from samples where the periostracum is removed mechanically and samples that are heated to temperatures that are sufficient to remove organic material but well below the temperature for thermal phase conversion from aragonite to calcite. The results show that the total organic content does not play a significant role in the aqueous mineral phase conversion. These results have potential implications for understanding carbonate mineral interactions in ocean sediments. Full article

(This article belongs to the Special Issue Texture and Microstructural Analysis of Crystalline Solids, Volume II)

21 pages, 1513 KiB

Open AccessArticle

Early Cretaceous A-Type Acidic Magmatic Belt in Northern Lhasa Block: Implications for the Evolution of the Bangong–Nujiang Ocean Lithosphere

by Deng **ao, **njie Yang, Chao Teng, Tianshe Cheng, Ning Zhu and Jun Cao

Minerals 2024, 14(7), 681; https://doi.org/10.3390/min14070681 (registering DOI) - 29 Jun 2024

Abstract

A-type granites have been the subject of considerable interest due to their distinct anorogenic geological background. The A-type and arc-related granites are crucial in deciphering the evolution of the ocean closure and continental collision in the Tibet Plateau. The demise of the Bangong–Nujiang [...] Read more.

A-type granites have been the subject of considerable interest due to their distinct anorogenic geological background. The A-type and arc-related granites are crucial in deciphering the evolution of the ocean closure and continental collision in the Tibet Plateau. The demise of the Bangong–Nujiang suture zone (BNSZ) and the Yarlung–Tsangpo suture zone was accompanied by the emplacement of volumes of syn-collisional and post-collisional granites. Controversy has persisted regarding the contribution of the collisional granites within the Lhasa Block to the growth of the Tibetan Plateau. This study provides key evidence about the evolution of the Lhasa Block and Bangong–Nujiang Ocean (BNO) by the newly documented 1200 km long, Early Cretaceous A-type acidic magmatic belt. The resolution was achieved through the utilization of petrology, whole-rock geochemistry, zircon U-Pb geochronology, and in situ zircon Hf isotope analysis of the Burshulaling Granites in the eastern segment and previous existing data in the central and western segment of the Lhasa Block. The Burshulaling Granites are characterized as peraluminous, high-K calc-alkaline series, indicating a post-collision setting with high temperature and low pressure. The zircon grains from two granite samples yield ²⁰⁶Pb/²³⁸U ages of 115–113 Ma. In situ zircon Hf analyses with ²⁰⁶Pb/²³⁸U ages give ε_Hf(t) of −6.2–0.6, showing prominent characteristics of crust-mantle interaction. Granites from east to west exhibit whole-rock geochemical and geochronological similarities that fall within the well-constrained Early Cretaceous time frame (117–103 Ma) and track post-collisional A-type acidic magmatic belt along BNSZ. We argue that this magmatism resulted from slab break-off or orogenic root detachment, leading to melting and mixing of the lower crust. Meanwhile, this study indicates the existence of the Bangong–Nujiang Ocean southward subduction or a collapse following an Andean-type orogen. Full article

(This article belongs to the Special Issue Genesis of Calc-Alkaline Granitic Rocks: Evidence from Petrology and Geochemistry)

17 pages, 4388 KiB

Open AccessArticle

Geochemical Study of the Osumi Granodiorite, Southwestern Japan

by Haozhen Xue, Kazuya Shimooka and Motohiro Tsuboi

Minerals 2024, 14(7), 680; https://doi.org/10.3390/min14070680 (registering DOI) - 29 Jun 2024

Abstract

The Osumi Granodiorite, located on the Osumi Peninsula in southwest Japan, is an example of outer zone granites that were formed during a limited period (13–15 Ma) in response to the subduction of the Philippine Sea Plate. This event, which is linked to [...] Read more.

The Osumi Granodiorite, located on the Osumi Peninsula in southwest Japan, is an example of outer zone granites that were formed during a limited period (13–15 Ma) in response to the subduction of the Philippine Sea Plate. This event, which is linked to the separation of southwest Japan from continental Asia, resulted in unique igneous activity. The Osumi Granodiorite is the largest Miocene granite body in the region. It intrudes into the Mesozoic to Paleogene accretionary complex of the Shimanto Belt and affects contact metamorphism. Despite considerable research on the Osumi Granodiorite, limited geochemical studies, especially on trace and rare earth element (REE) analyses, have been conducted. Furthermore, there are insufficient data on the Rb–Sr isotopic system, leaving the formation process unclear. This study presents whole-rock geochemical and Rb-Sr isotopic data to investigate the petrogenesis of the Osumi Granodiorite. The results suggest a common magma origin for this pluton, as indicated by linear trends on the Harker diagrams and similar REE patterns. The presence of a relatively large Eu anomaly implies formation under a reducing environment. The AKF diagram indicates predominant contamination by pelitic rocks of the Shimanto Belt during magma formation. The Rb–Sr whole-rock isochron diagram and SrI–1000/Sr diagram suggest that the Osumi Granodiorite body was formed by heterogeneous assimilation of magma into the Shimanto Belt. Furthermore, the whole-rock isochron age is 64.3 Ma, which differs by approximately 50 My from the previously reported biotite K–Ar age (14–22 Ma). This age is considered to be a pseudo-isochron age, rather than the consolidation age. During the middle Miocene, the compressive stress field in the outer zone south of the Butsuzo Tectonic Line made it difficult for magma to rise. As a result, it reacted with the sedimentary rocks of the Shimanto Belt to various degrees. The Osumi Granodiorite underwent magma differentiation upon intrusion into the Shimanto Belt. It subsequently ascended, cooled, and interacted with pelitic rocks under stable geological conditions. Full article

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

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38 pages, 14520 KiB

Open AccessArticle

Mineralogy and Geochemistry of Titaniferous Iron Ores in El-Baroud Layered Gabbros: Fe-Ti Ore Genesis and Tectono-Metallogenetic Setting

by Mohamed Zaki Khedr, Ahmed Moftah, N. H. El-Shibiny, Akihiro Tamura, Wei Tan, Yuji Ichiyama, Eiichi Takazawa, Ali Y. Kahal and Kamal Abdelrahman

Minerals 2024, 14(7), 679; https://doi.org/10.3390/min14070679 (registering DOI) - 29 Jun 2024

Abstract

The Neoproterozoic pyroxene gabbros and gabbronorites in the El-Baroud mafic intrusion in the Northern Eastern Desert (NED) of Egypt host Fe-Ti oxide ore deposits. This study discusses the major and trace elements of both titaniferous iron ores and their host rocks, along with [...] Read more.

The Neoproterozoic pyroxene gabbros and gabbronorites in the El-Baroud mafic intrusion in the Northern Eastern Desert (NED) of Egypt host Fe-Ti oxide ore deposits. This study discusses the major and trace elements of both titaniferous iron ores and their host rocks, along with the mineral chemistry (major and in situ trace elements) of interstitial clinopyroxene (Cpx), to gain a deeper understanding of the Fe-Ti oxide genesis. These ores occur as disseminated (55–60 vol.% of Fe-Ti oxides) and massive types (85–95 vol.%) in the form of the dyke, layer, and lens. They are composed of titanomagnetite (80–87 vol.%) with subordinate ilmenite (10–15 vol.%) and magnetite (3–5 vol.%), in accordance with their high Fe₂O₃ (75.66 wt.% on average) and TiO₂ contents (16.30–17.60 wt.%). The Cpx in the investigated ores is diopside composition (Mg#; 0.72–0.83) and exhibits a nearly convex upward REE pattern, similar to Cpxs in the ferropicrite that originated from the primitive mantle. Melts in equilibrium with this Cpx resemble Greenstone ferropicrite melts; the parent melt of El-Baroud gabbros is possibly a ferropicritic melt that was derived from the lithospheric mantle during plume interaction. The El-Baroud gabbroic rocks were generated during the arc rifting and crystallized under a high oxygen fugacity at a temperature of 800–1000 °C and a pressure of 3 kbar with a depth of 12 km. The Fe-Ti oxide ores have been formed from ferropicritic parent melts by two processes, including in situ crystallization that leads to the formation of disseminated Fe-Ti oxides in the iron-rich gabbros at the bottom and liquid immiscibility that is responsible for the formation of thick Fe-Ti ore lenses and layers at the top of the gabbroic intrusion. Initially, titanomagnetite crystallized from the primary Ti-rich oxide melt. As cooling progressed, some of the excess titanium in this melt was exsolved in the form of the exsolution ilmenite lamellae within the titanomagnetite. The Fe-Ti oxide layers in the NED follow the trend of NW-SE (Najd trend), where their distribution is possibly controlled by the composition of parent melts (rich in Ti and Fe), high oxygen fugacity, and the structure related to the Najd fault system. The distribution of Fe-Ti oxide ores increases from the NED to the Southern Eastern Desert (SED), suggesting the dominant mantle plumes and/or shear zones in the SED relative to the NED. Full article

(This article belongs to the Special Issue Using Mineral Chemistry to Characterize Ore-Forming Processes)

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24 pages, 3941 KiB

Open AccessArticle

Unraveling Dry Jigging: Insights into Pulsation, Energy Consumption, and Stratification Dynamics

by Fortunato Lucas Quembo Raposo, Carlos Otávio Petter and Weslei Monteiro Ambrós

Minerals 2024, 14(7), 678; https://doi.org/10.3390/min14070678 (registering DOI) - 28 Jun 2024

Abstract

The increasing concerns regarding water usage in mineral processing have led to a growing interest in dry jigging in recent years. However, there is still a need for a more comprehensive examination of the operational aspects of the technique. In this sense, this [...] Read more.

The increasing concerns regarding water usage in mineral processing have led to a growing interest in dry jigging in recent years. However, there is still a need for a more comprehensive examination of the operational aspects of the technique. In this sense, this study focused on three main elements: (a) examining the air pulse pattern during dry jig operation; (b) assessing the evolution of the stratification profile over time using partition analysis; and (c) evaluating the specific energy consumption of batch dry jigging during operation. Also, an innovative operational strategy known as "transient pulsing" was proposed and analyzed, involving varying the intensity and frequency of the air pulse throughout the stratification process. All tests were conducted using density tracers spread across 11 density ranges (0.4–2.4 g/cm³) and a base bed (gravel) to analyze their separation in a batch, pilot-scale dry jig. Pressure drop and active power data were collected to measure the pulse characteristics and energy consumption. The airflow curves, obtained through pressure drop data, indicated that the pulsation process is more unstable as the airflow increases, possibly due to the pressure fluctuations experienced by air during valve closure. For the pulsation conditions used in the tests, the specific energy consumption was 10.66 Wh/kg of jigged material, with most of it related to the blower drive system. Analysis of the stratification evolution over time showed an oscillatory behavior, alternating between states of better (Ep < 0.1) and worse (Ep > 0.1) separation, especially for the near-gravity material (NGM). Results of the transient pulsation tests suggested that progressively increasing the vertical displacement of the bed during stratification resulted in slightly better segregation levels and more stable jigging evolution over time in comparison to stationary pulse conditions. Full article

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

16 pages, 7136 KiB

Open AccessArticle

Application of Integrated Geological and Geophysical Surveys on the Exploration of Chalcedony Deposits: A Case Study on Nanhong Agate in Liangshan, China

by Sheng** Gong, Keqiang Zhao, Mingming Wang, Shengwu Yan, Yong Li and Jianzhou Yang

Minerals 2024, 14(7), 677; https://doi.org/10.3390/min14070677 (registering DOI) - 28 Jun 2024

Abstract

Nanhong agate, esteemed for its vivid color and natural shine, is experiencing a scarcity in supply despite its high demand. The primary deposits of agate, typically found near the surface, have not been extensively explored due to the predominance of traditional manual excavation [...] Read more.

Nanhong agate, esteemed for its vivid color and natural shine, is experiencing a scarcity in supply despite its high demand. The primary deposits of agate, typically found near the surface, have not been extensively explored due to the predominance of traditional manual excavation methods. This research examined the Nanhong agate deposits in the Zhaojue–Meigu region of Liangshan, China, employing the integration of geological and geophysical surveys. Field geological surveys allowed us to outline the general areas where agate is found. Following this, using magnetic surveys, vertical electrical sounding, and controlled-source audio magnetotellurics, agate deposits were located within the conglomerate layer of the second member of the Feixianguan Formation from the Lower Triassic period at depths of less than 100 m. Our results identify mineralized layers, Xuanwei Formation mudstone, and the underlying bedrock, thus supporting the creation of a mineral prediction map. This research provides essential insights and guidance for agate exploration and the development of associated mineral resources. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

13 pages, 2111 KiB

Open AccessArticle

Feasibility Analysis of Bacterial-Treated Coal Gangue for Soil Improvement: Growth-Promoting Effects of Alfalfa

by Yaya Wang, Mingwu Liu, Zhiting Di, Weilong Cao and Shihua He

Minerals 2024, 14(7), 676; https://doi.org/10.3390/min14070676 (registering DOI) - 28 Jun 2024

Abstract

The long-term storage of coal gangue (CG) mountains causes serious environmental problems such as water and air pollution. Thus, sustainable reclamation practices are urgently needed to minimize the environmental impacts brought by CG mountains. Pikovskaya medium was employed to screen microorganisms, which were [...] Read more.

The long-term storage of coal gangue (CG) mountains causes serious environmental problems such as water and air pollution. Thus, sustainable reclamation practices are urgently needed to minimize the environmental impacts brought by CG mountains. Pikovskaya medium was employed to screen microorganisms, which were subsequently utilized to promote the solubilization of CG. XRF, SEM, XRD, and HPLC techniques were employed to characterize the CG before and after bacterial treatment. In this study, we have successfully isolated and purified a bacterial strain, identified as Stenotrophomonas bentonitica BII-R7, which possesses the ability to facilitate the solubilization of nutrient elements from CG. Factors including initial inoculation ratio, incubation time, CG particle size, CG concentration, pH, and temperature were examined to investigate their effects on the biosolubilization of CG. Furthermore, the mechanism underlying the CG solubilization was also probed. Our data demonstrated that low-molecular-weight organic acids, such as acetic acid and formic acid, may harbor a crucial role in promoting the solubilization of CG. Lastly, we found that Stenotrophomonas bentonitica BII-R7, in conjugation with CG, can increase the alfalfa seed germination percentage and promote the growth of alfalfa. Together, these data provide evidence that bacterial-treated CG can be utilized for soil improvement and land reclamation. Full article

(This article belongs to the Section Biomineralization and Biominerals)

16 pages, 1640 KiB

Open AccessArticle

Mineralogy of Gold, Tellurides and Sulfides from Lianzigou Gold Deposits in the **aoqinling Region, Central China: Implications for Ore-Forming Conditions and Processes

by Guoming Weng, Jiajun Liu, Emmanuel John M. Carranza, Fangfang Zhang, Degao Zhai, Yinhong Wang, Shen Gao, Mingyang Si, Zaixin Su and Yingying Zhang

Minerals 2024, 14(7), 675; https://doi.org/10.3390/min14070675 (registering DOI) - 28 Jun 2024

Abstract

The Lianzigou deposit, which has an Au–Te paragenetic association, is hosted in plagioclase gneiss of the Qincanggou Formation in the Taihua Group in the **aoqinling region, central China. This quartz vein-type Au deposit comprises native Au and a variety of tellurides. The latter [...] Read more.

The Lianzigou deposit, which has an Au–Te paragenetic association, is hosted in plagioclase gneiss of the Qincanggou Formation in the Taihua Group in the **aoqinling region, central China. This quartz vein-type Au deposit comprises native Au and a variety of tellurides. The latter include calaverite (AuTe₂), krennerite (Au₃AgTe₈), petzite (Au₃AgTe₂), hessite (Ag₂Te), melonite (NiTe₂), and altaite (PbTe). Four stages have been recognized in this deposit: stage I consists of K-feldspar and quartz; stage II is of milky quartz veins accompanied by coarse-grained disseminated and lumps of pyrite with weak Au mineralization; stage III is composed mainly of Au, tellurides, and sulfides; and stage IV is characterized by abundant carbonate and quartz. Based on mineral assemblage and thermodynamic data, we estimated the physicochemical conditions of the main metallogenic stages. Based on thermodynamic modelling, the physicochemical conditions of Au–Ag–Te mineral associations were estimated. The Au–Ag–Te minerals from stage III formed mainly under conditions of logƒO₂ = −43.15 to −33.31, logƒH₂S = ~−9.29, pH < 7, logfTe₂ = −10.6 to −9.8 and logαAu⁺/αAg⁺ = −7.2 to −6.5. In contrast, the physicochemical conditions of stage II were higher, specifically pH (8.3–8.5) and logƒO₂ (−34.90−31.96). In the ore-forming fluids of the Lianzigou deposit, the dominant Au species was Au(HS)₂⁻ while the dominant Te species were HTe⁻(aq) and Te₂²⁻(aq). Moreover, the Au–Ag–Te metal associations in the Lianzigou Au deposit were derived from mantle materials related to lithospheric thinning of the eastern North China craton in the Early Cretaceous under an extensional tectonic system. Full article

(This article belongs to the Section Mineral Deposits)

12 pages, 1486 KiB

Open AccessArticle

Use of Submarine Tailings Disposal as Alternative Tailings Management System

by Erol Yilmaz

Minerals 2024, 14(7), 674; https://doi.org/10.3390/min14070674 (registering DOI) - 28 Jun 2024

Abstract

The importance of the mining/milling industry in increasing the growth level and welfare of countries is quite high. However, at the end of mining/milling processes, huge amounts of waste (often known as tails) are inevitably produced that have no economic value and can [...] Read more.

The importance of the mining/milling industry in increasing the growth level and welfare of countries is quite high. However, at the end of mining/milling processes, huge amounts of waste (often known as tails) are inevitably produced that have no economic value and can even be considered dangerous due to some heavy metals they contain. These tails are highly problematic due to both their volume (difficult to manage environmentally) and toxicity (potential to cause acid/leach waters) and need to be handled outside of existing disposal methods. This article presents the effective and sustainable handling and application of tails resulting from the enrichment of copper–zinc ores, which are actively engaged in metallic mining activities in the northeast of Türkiye, with the submarine tails disposal (STD) method. In the mining operation under study, some (55–60 wt.%) of the tails are employed as underground fill, even though the residual part is disposed of by the STD method. The characterization of ore beneficiation tails, their transportation to the subsea via a pipeline system, and discharge monitoring results are detailed in the present investigation. According to the limitations which are indicated by the Turkish Control of Water Contamination regulation, the concentration of Pb-Cu found in the results was under the allowable limit of 0.05 mg/L. The allowed 2 mg/L limit for Zn was not surpassed mainly by the concentration found in the collected samples. pH values were almost above the allowable limit of pH > 5. The results reveal that the STD technique works quite well as an integrated mine tails method in the mine under study. Full article

(This article belongs to the Special Issue Cemented Mine Waste Backfill: Experiment and Modelling: 2nd Edition)

18 pages, 1863 KiB

Open AccessArticle

Stability Analysis of a Mine Wall Based on Different Roof-Contact Filling Rates

by Jiang Guo, Wenjun Yang, Yan Zhao and Wanzhong Zhang

Minerals 2024, 14(7), 673; https://doi.org/10.3390/min14070673 (registering DOI) - 28 Jun 2024

Abstract

This study takes the mine wall of the isolated mine pillar in the Dongguashan Copper Mine as the research object. Based on the mechanical model of the mine wall under the trapezoidal loading of the backfill, the expressions for calculating the safety factor [...] Read more.

This study takes the mine wall of the isolated mine pillar in the Dongguashan Copper Mine as the research object. Based on the mechanical model of the mine wall under the trapezoidal loading of the backfill, the expressions for calculating the safety factor of the mine wall were derived by considering the load-bearing conditions of the backfill–mine-wall system under different roof-contacted filling rates. On this basis, the variation law of the safety factor of the mine wall with the roof-contacted filling rate was obtained, and the calculation result was verified by a numerical simulation and a field test. The research shows that for the same mine wall width, when the roof-contacted filling rate exceeds 9.53%, the safety factor of the mine wall exhibits a "trapezoidal" variation pattern with the increase in the roof-contacted filling rate. Moreover, the comprehensive benefits of isolated pillar recovery are made more credible by maintaining a wall width of 3 m and a filler jointing rate between 30% and 74.49%. This study analyzes the effect of the roof-contacted filling rate on the stability of the mine wall, which can provide a theoretical basis for mining isolated pillars by the filler method in deep mines. Full article

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

3 pages, 178 KiB

Open AccessEditorial

Editorial for Special Issue: “Geochemistry and Mineralogy of Basic–Ultrabasic and Alkaline Intrusions and Related Magmatic Deposits”

by Nadezhda Krivolutskaya

Minerals 2024, 14(7), 672; https://doi.org/10.3390/min14070672 (registering DOI) - 28 Jun 2024

Abstract

Magmatic deposits are sources of strategic metals provided to the global market. Ultramafic–mafic intrusions contain PGE, Cu-Ni, Cr, Ti, and V deposits, while many rare metal deposits (e.g., Zr, Ta, Nb, Be, Y, Sc, Li, and Ge) are linked to alkaline intrusions. Full article

(This article belongs to the Special Issue Geochemistry and Mineralogy of Basic–Ultrabasic and Alkaline Intrusions and Related Magmatic Deposits)

37 pages, 46986 KiB

Open AccessArticle

Barite Replacement as a Key Factor in the Genesis of Sediment-Hosted Zn-Pb±Ba and Barite-Sulfide Deposits: Ore Fluids and Isotope (S and Sr) Signatures from Sediment-Hosted Zn-Pb±Ba Deposits of Iran

by Abdorrahman Rajabi, Pouria Mahmoodi, Pura Alfonso, Carles Canet, Colin Andrew, Saeideh Azhdari, Somaye Rezaei, Zahra Alaminia, Somaye Tamarzadeh, Ali Yarmohammadi, Ghazaleh Khan Mohammadi and Rasoul Saeidi

Minerals 2024, 14(7), 671; https://doi.org/10.3390/min14070671 (registering DOI) - 28 Jun 2024

Abstract

Iran hosts more than 350 Precambrian to Cenozoic sediment-hosted Zn-Pb±Ba and barite-sulfide deposits, including shale-hosted massive sulfide (SHMS, also called SEDEX) and Irish-type and Mississippi Valley-type (MVT) mineralization, and barite is a common mineral in these deposits. In the SHMS deposits, barite is [...] Read more.

Iran hosts more than 350 Precambrian to Cenozoic sediment-hosted Zn-Pb±Ba and barite-sulfide deposits, including shale-hosted massive sulfide (SHMS, also called SEDEX) and Irish-type and Mississippi Valley-type (MVT) mineralization, and barite is a common mineral in these deposits. In the SHMS deposits, barite is typically found as fine-grained disseminations in thin laminae. In these deposits, the sulfide laminae often occur as diagenetic replacements and as bands containing authigenic and diagenetic barite and pyrite framboids. In the Irish-type Zn-Pb-Ba and stratabound barite-sulfide deposits, barite exhibits various textures, including fine-grained disseminated barite, banded zebra textures, veins, and massive barite lenses. In some of the giant Irish-type deposits, as well as in the stratabound barite-sulfide mineralization, the main stratabound sulfide ore is developed within a barite envelope and is characterized by the replacement of barite and pyrite by chalcopyrite, galena, and sphalerite. In the MVT deposits, the formation of barite is often related to dolomitization, and sulfide mineralization involves the replacement of the dolomitized carbonate rocks, as well as associated barite. Fluid inclusion studies on the Irish-type deposits indicate that the temperatures and salinities of the sulfide-forming fluids are higher compared to those of the barite-forming fluids. Fluid inclusion analyses of coarse-grained barites from Irish and MVT deposits reveal their hydrothermal origin. The δ³⁴S values of sulfide minerals (pyrite, sphalerite, and galena) in Irish-type deposits exhibit a broad range of low values (mostly −28 to +5‰), primarily revealing a process of bacterial sulfate reduction (BSR). However, the textures (replacement, colloform, and banded) and more positive sulfur isotope values (+1 to +36‰) in the SHMS Zn-Pb deposits suggest that bacterial sulfate reduction (BSR) plays a less significant role. We suggest that thermochemical sulfate reduction (TSR) connected to the direct replacement of barite plays a more relevant role in providing sulfur for the sulfide mineralization in the SHMS, barite-sulfide, and MVT deposits. Based on the textual evidence, sulfur isotopic data, and fluid inclusion studies, barite has been identified as a key controller for the subsequent Zn-Pb mineralization by providing a suitable host and significant sulfur contribution in the sediment-hosted Zn-Pb and stratabound barite-sulfide deposits. This implies that diagenetic barite might be a precursor to all types of sediment-hosted Zn-Pb mineralization. Full article

(This article belongs to the Special Issue Stratabound Barite Deposits: Mineralogy, Isotope Geochemistry and Geochronology)

25 pages, 6355 KiB

Open AccessArticle

Numerical Investigation of the Applicability of Preferential Grade Deportment by Size

by Nazym Baizhiyen, Peter Dowd, Chaoshui Xu and David Lewis

Minerals 2024, 14(7), 670; https://doi.org/10.3390/min14070670 - 28 Jun 2024

Abstract

The effective separation of ore is based on two fundamental processes: liberation and separability. Liberation involves the reduction of size, yielding smaller particles with enhanced compositional homogeneity. Understanding liberation requires an understanding of rock breakage, as it impacts mineral liberation and helps identify [...] Read more.

The effective separation of ore is based on two fundamental processes: liberation and separability. Liberation involves the reduction of size, yielding smaller particles with enhanced compositional homogeneity. Understanding liberation requires an understanding of rock breakage, as it impacts mineral liberation and helps identify ores suitable for pre-concentration. Non-random breakage, influenced by textural and mineral properties, introduces heterogeneity in mineral distribution across size fractions. Physical attributes, including ore and gangue mineralogy and texture, influence fractionation tendencies during breakage. Notably, the presence of mineralization in veins substantially assists early-stage liberation in mineral processing. The aim of this study is to develop a methodology that allows the prediction of natural fractionation tendencies based on geological, mineralogical, and textural data using Discrete Element Method (DEM) modeling. DEM simulations provide insights into granular material behavior, capturing phenomena such as crack initiation and propagation. The use of DEM, particularly with models such as the Flat Joint Model (FJM), enhances our understanding of rock damage mechanisms. In this paper, DEM is used to predict preferential grade by size deportment, and a numerical model is developed to reflect grade distributions across size fractions. A fragmentation analysis is conducted after rock breakage simulations using DEM to analyze the fragment sizes and grades and calculate the Response Rankings of synthetic specimens. Full article

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

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