Minerals

30 pages, 16155 KiB

Open AccessArticle

Paleoenvironmental Transition during the Rhuddanian–Aeronian and Its Implications for Lithofacies Evolution and Shale Gas Exploration: Insights from the Changning Area, Southern Sichuan Basin, South-West China

by Hangyi Zhu

Minerals 2024, 14(9), 949; https://doi.org/10.3390/min14090949 - 18 Sep 2024

Abstract

During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. [...] Read more.

During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. This study investigates the Longmaxi Formation shale in the Changning area in the Southern Sichuan basin, focusing on 28 core samples from Well N1. Using scanning electron microscopy, QEMSCAN, TOC, XRD, and major and trace element analyses, we reconstructed the paleoenvironmental transitions of this period and explored their control over shale lithofacies types and mineral compositions. Four shale lithofacies were identified: carbonate rich lithofacies (CRF), biogenic quartz-rich lithofacies (BQRF), detrital clay-rich lithofacies (CRDF), and detrital quartz-rich lithofacies (DQRF). During the Rhuddanian period, rising global temperatures caused glacial melting and rapid marine transgressions. The low oxygen levels in bottom waters, combined with upwelling and abundant volcanic material, led to high paleoproductivity. This period primarily developed BQRF and CRF. Rich nutrients and abundant siliceous organisms, along with anoxic to anaerobic conditions, provided the material basis and preservation conditions for high biogenic quartz and organic matter content. High paleoproductivity and anoxic conditions also facilitated the precipitation of synsedimentary calcite and supplied Mg²⁺ and SO₄²⁻ for the formation of iron-poor dolomite via sulfate reduction. From the Late Rhuddanian to the Mid-Aeronian, the Guangxi orogeny caused sea levels to fall, increasing water oxidation and reducing upwelling and volcanic activity, which lowered paleoproductivity. Rapid sedimentation rates, stepwise global temperature increases, and the intermittent intensification of weathering affected terrigenous clastic input, resulting in the alternating deposition of CRF, CRDF, and DQRF. Two favorable shale gas reservoirs were identified from the Rhuddanian–Aeronian period: Type I (BQRF) in the L1–L3 Layers, characterized by high TOC and brittleness, and Type II (DQRF) in the L4 Layer, with significant detrital quartz content. The Type I-favorable reservoir supports ongoing gas production, and the Type II-favorable reservoir offers potential as a future exploration target. Full article

(This article belongs to the Special Issue Environment and Geochemistry of Sediments, 2nd Edition)

24 pages, 8983 KiB

Open AccessArticle

Microseismic Monitoring and Disaster Warning via Mining and Filling Processes of Residual Hazardous Ore Bodies

by Zilong Zhou, Yinghua Huang and Congcong Zhao

Minerals 2024, 14(9), 948; https://doi.org/10.3390/min14090948 - 18 Sep 2024

Abstract

The thick ore bodies in the Xianglushan tungsten mine have been irregularly mined, forming a super large, connected irregular goaf group and tall, isolated irregular pillars inside. At the same time, there is a production capacity task of recovering residual and dangerous ore [...] Read more.

The thick ore bodies in the Xianglushan tungsten mine have been irregularly mined, forming a super large, connected irregular goaf group and tall, isolated irregular pillars inside. At the same time, there is a production capacity task of recovering residual and dangerous ore bodies. This poses the potential for serious ground-pressure disasters, such as roof caving, pillar collapse, and large-scale goaf collapse during mining. Based on the actual needs of the site, we established a microseismic monitoring system. After analyzing the mining and filling processes and their relationships, and, combined with the distribution characteristics of microseismic multiple parameters, we constructed a ground-pressure disaster warning mode and mechanism. We analyzed the stability of the goaf, further formed a warning system, and achieved disaster warning. In response to the current situation of the difficulty of early warning of ground pressure in the Xianglushan tungsten mine, continuous on-site monitoring of existing goaves, point pillars, and strip pillars, as well as analysis of stress changes during dynamic mining and filling processes, we explored scientific and reasonable early warning mechanisms and models, understanding the relationship between the changes in microseismic parameters during dynamic mining and filling processes and ground pressure, studying and improving the reliability of underground microseismic monitoring and early warning, and achieved the internal connection between building early warning systems and the prevention of ground-pressure disasters. The results indicate that the mining and filling process of the ore body is the main factor in maintaining a stable and balanced distribution of underground ground pressure in mining engineering. Microseismic monitoring can invert the evolution of ground pressure and form a feedback system with ground-pressure warning, achieving mine safety management. Full article

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23 pages, 1759 KiB

Open AccessArticle

Characterization of Humic Acid Salts and Their Use for CO₂ Reduction

by Tomasz Spietz, Maira Kazankapova, Szymon Dobras, Zhanar Kassenova, Bolat Yermagambet, Andrey Y. Khalimon and Sławomir Stelmach

Minerals 2024, 14(9), 947; https://doi.org/10.3390/min14090947 - 18 Sep 2024

Abstract

The European Union aims to be climate neutral by 2050. To achieve this ambitious goal, net greenhouse gas emissions must be reduced by at least 55% by 2030. Post-combustion CO₂ capture methods are essential to reduce CO₂ emissions from the chemical [...] Read more.

The European Union aims to be climate neutral by 2050. To achieve this ambitious goal, net greenhouse gas emissions must be reduced by at least 55% by 2030. Post-combustion CO₂ capture methods are essential to reduce CO₂ emissions from the chemical industry, power generation, and cement plants. To reduce CO₂, it must be captured and then stored underground or converted into other valuable products. Apromising alternative for CO₂ reduction is the use of humic acid salts (HASs). This work describes a process for the preparation of potassium (HmK) and ammonium (HmA) humic acid salts from oxidized lignite (leonardite). A detailed characterization of the obtained HASs was conducted, including elemental, granulometric, and thermogravimetric analyses, as well as 1H-NMR and IR spectroscopy. Moreover, the CO₂ absorption capacity and absorption rate of HASs were experimentally investigated. The results showed that the absorption capacity of the HASs was up to 10.9 g CO₂ per kg. The CO₂ absorption rate of 30% HmA solution was found to be similar to that of 30% MEA. Additionally, HmA solution demonstrated better efficiency in CO₂ absorption than HmK. One of the issues observed during the CO₂ absorption was foaming of the solutions, which was more noticeable with HmK. Full article

(This article belongs to the Special Issue Carbon Dioxide Storage, Utilization & Reduction)

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21 pages, 10207 KiB

Open AccessArticle

Hydrothermal Karstification of the Pre-Messinian Eonile Canyon: Geomorphological and Geochemical Evidences for Hypogene Speleogenesis in the Middle Nile Valley of Egypt

by Ashraf A. Mostafa, Hatem M. El-Desoky, Diaa A. Saadawi, Ahmed M. Abdel-Rahman, John Webb, Hassan Alzahrani, Fahad Alshehri, Abdurraouf Okok, Ahmed E. Khalil and Eman A. Marghani

Minerals 2024, 14(9), 946; https://doi.org/10.3390/min14090946 - 16 Sep 2024

Abstract

The surface and subsurface karst features of the Eocene limestone plateaus along the Middle Nile Valley in Egypt were formerly believed to be epigene in origin and to have developed during post-Eocene pluvial periods. However, the morphology of the caves and their restriction [...] Read more.

The surface and subsurface karst features of the Eocene limestone plateaus along the Middle Nile Valley in Egypt were formerly believed to be epigene in origin and to have developed during post-Eocene pluvial periods. However, the morphology of the caves and their restriction to particular stratigraphic intervals suggests that they are hypogene. The geochemistry and mineralogy of the soft, thick-bedded, brown/black cave infills shows that these sediments originated from hydrothermal processes, as evidenced by their Fe, Mn, Co, Ni, and Cu concentrations. Thus, the karst features are hypogene and probably formed during the opening of the Red Sea Rift at the end of the Oligocene and early Miocene. At this time, there was abundant volcanic activity, as shown by basalt lavas ~70 km northwest of Assiut; this triggered the release of large amounts of CO₂ that made the hydrothermal waters acidic and dissolved the caves. Full article

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22 pages, 12866 KiB

Open AccessArticle

Application of Machine Learning to Characterize Metallogenic Potential Based on Trace Elements of Zircon: A Case Study of the Tethyan Domain

by Jin Guo and Wen-Yan He

Minerals 2024, 14(9), 945; https://doi.org/10.3390/min14090945 - 16 Sep 2024

Abstract

Amidst the rapid advancement of artificial intelligence and information technology, the emergence of big data and machine learning provides a new research paradigm for mineral exploration. Focusing on the Tethyan metallogenic domain, this paper conducted a series of research works based on machine [...] Read more.

Amidst the rapid advancement of artificial intelligence and information technology, the emergence of big data and machine learning provides a new research paradigm for mineral exploration. Focusing on the Tethyan metallogenic domain, this paper conducted a series of research works based on machine learning methods to explore the critical geochemical element signals that affect the metallogenic potential of porphyry deposits and reveal the metallogenic regularity. Binary classifiers based on random forest, XGBoost, and deep neural network are established to distinguish zircon fertility, and these machine learning methods achieve higher accuracy, exceeding 90%, compared with the traditional geochemical methods. Based on the random forest and SHapley Additive exPlanations (SHAP) algorithms, key chemical element characteristics conducive to magmatic mineralization are revealed. In addition, a deposit classification model was constructed, and the t-SNE method was used to visualize the differences in zircon trace element characteristics between porphyry deposits of different mineralization types. The study highlights the promise of machine learning algorithms in metallogenic potential assessment and mineral exploration by comparing them with traditional chemical methods, providing insights into future mineral classification models utilizing sub-mineral geochemical data. Full article

(This article belongs to the Special Issue The Formation and Evolution of Gold Deposits in China)

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14 pages, 3804 KiB

Open AccessArticle

Study on the Effects of Microwave Heating Time and Power on the Mechanical Properties of Cemented Tailings Backfill

by Pengchu Ding, Shiheng Yan, Qinqiang Guo, Liwu Chang, Zhen Li, Changtai Zhou, Dong Han and Jie Yang

Minerals 2024, 14(9), 944; https://doi.org/10.3390/min14090944 - 15 Sep 2024

Abstract

With the escalating demand for advanced and eco-friendly processing technologies in mining engineering, the potential applications of microwave heating technology in the treatment of cement tailings backfill (CTB) are expanding significantly. This research comprehensively investigates the mechanisms through which microwave irradiation duration and [...] Read more.

With the escalating demand for advanced and eco-friendly processing technologies in mining engineering, the potential applications of microwave heating technology in the treatment of cement tailings backfill (CTB) are expanding significantly. This research comprehensively investigates the mechanisms through which microwave irradiation duration and power influence the mechanical properties of CTB with varying concentrations and cement-to-sand ratios. The aim is to reveal the influencing patterns through experimental methods, providing scientific evidence for optimizing CTB treatment processes. This paper conducted microwave heating tests, uniaxial compression tests, and SEM-EDS tests on CTB. The research results indicate that heating time and power significantly enhance the early strength of CTB, with a more pronounced effect on CTB with higher concentrations and higher cement–sand ratios. When the heating time is 7 min and the heating power is 340 W, the cement hydration reaction is maximally promoted, thereby increasing the density and strength growth rate of CTB. However, excessively long heating time or overly high heating power may cause microcracks or thermal stress concentration within the CTB, adversely affecting the strength growth rate of CTB. Optimal thermal exposure duration and microwave power settings facilitate the activation of cementitious materials and the nucleation of calcium-silicate-hydrate (C-S-H) phases, thereby accelerating the compressive strength evolution of cemented tailings backfill (CTB). The outcomes of this research offer valuable insights into the deployment of microwave heating methodologies in underground mine backfilling, which are pivotal for augmenting the economic viability and environmental sustainability of mining operations. Full article

(This article belongs to the Topic New Advances in Mining Technology)

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31 pages, 4027 KiB

Open AccessReview

Toward Viable Industrial Solid Residual Waste Recycling: A Review of Its Innovative Applications and Future Perspectives

by Tugba Keskin, Erol Yilmaz, Tugrul Kasap, Muhammet Sari and Shuai Cao

Minerals 2024, 14(9), 943; https://doi.org/10.3390/min14090943 - 15 Sep 2024

Abstract

Industrial solid residual waste (ISRW) generated during and/or due to the making of energy, heat, and raw materials poses a major threat to a sustainable future due to its large production quantities and complex characteristics. Especially improper disposal of ISRW (e.g., coal ashes, [...] Read more.

Industrial solid residual waste (ISRW) generated during and/or due to the making of energy, heat, and raw materials poses a major threat to a sustainable future due to its large production quantities and complex characteristics. Especially improper disposal of ISRW (e.g., coal ashes, municipal waste residue, and biomass ashes) not only threatens human health but can also cause environmental hazards such as water, soil, and air pollution, upsetting the global balance. Given the environmental impacts as well as increasingly stringent disposal regulations, lack of landfills, and economic constraints, more sustainable and naturally friendly management strategies are being adopted for ISRW. While numerous studies in the literature have considered various characteristics of ISRW, a complete appraisal of the entire practice, from making to disposal, is still lacking. This paper presents an overview of the making, features, and traditional and innovative managing tactics of ISRW within the context of a general legal framework. This paper provides a scientific review of the various production types, global production quantities, and characteristics of ISRW. Additionally, the orthodox management strategies of ISRWs are scrutinized from a sociological and ecological standpoint, and diverse techniques for more viable and secure management are elucidated. This review culminates in an examination of the global impact and advantages of ISRW management policies based on legislation and regulations. Consequently, this paper seeks to elucidate the extant practices and a few recent advancements pertaining to ISRWs. Additionally, it underscores the ecological, sociological, and economic issues engendered by ISRWs and proposes innovative applications and production technologies. Full article

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

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17 pages, 6340 KiB

Open AccessArticle

Shale Oil Generation Conditions and Exploration Prospects of the Cretaceous Nenjiang Formation in the Changling Depression, Songliao Basin, China

by Wenjun Zhang, Wenyu Zhang, Shumin Lin, Xing Ke, Min Zhang and Taohua He

Minerals 2024, 14(9), 942; https://doi.org/10.3390/min14090942 - 15 Sep 2024

Abstract

Low-maturity shale oil predominates in shale oil resources. China’s onshore shale oil, particularly the Cretaceous Nenjiang Formation in the Songliao Basin, holds significant potential for low-maturity shale oil, presenting promising exploration and development prospects. This study delves into the hydrocarbon generation conditions, reservoir [...] Read more.

Low-maturity shale oil predominates in shale oil resources. China’s onshore shale oil, particularly the Cretaceous Nenjiang Formation in the Songliao Basin, holds significant potential for low-maturity shale oil, presenting promising exploration and development prospects. This study delves into the hydrocarbon generation conditions, reservoir characteristics, and oil-bearing property analysis of the mud shale from the Nen-1 and Nen-2 sub-formations of the Nenjiang Formation to pinpoint favorable intervals for shale oil exploration. Through the integration of lithology, pressure, and fracture distribution data in the study area, favorable zones were delineated. The Nen-1 sub-formation is widely distributed in the Changling Depression, with mud shale thickness ranging from 30 to 100 m and a total organic content exceeding 2.0%. Type I kerogen predominated as the source rock, while some samples contained type II kerogen. Organic microcomponents primarily comprised algal bodies, with vitrinite reflectance (R_o) ranging from 0.5% to 0.8%. Compared to Nen-1 shale, Nen-2 shale exhibited less total organic content, kerogen type, and thermal evolution degree, albeit both are conducive to low-maturity shale oil generation. The Nen-1 and Nen-2 sub-formations predominantly consist of clay, quartz, feldspar, calcite, and pyrite minerals, with minor dolomite, siderite, and anhydrite. Hydrocarbons primarily reside in microfractures and micropores, including interlayer micropores, organic matter micropores, intra-cuticle micropores, and intercrystalline microporosity, with interlayer and intra-cuticle micropores being dominant. The free oil content (S₁) in Nen-1 shale ranged from 0.01 mg/g to 5.04 mg/g (average: 1.13 mg/g), while in Nen-2 shale, it ranged from 0.01 mg/g to 3.28 mg/g (average: 0.75 mg/g). The Nen-1 and Nen-2 sub-formations are identified as potential intervals for shale oil exploration. Considering total organic content, oil saturation, vitrinite reflectance, and shale formation thickness in the study area, the favorable zone for low-maturity shale oil generation is primarily situated in the Heidimiao Sub-Depression and its vicinity. The Nen-2 shale-oil-enriched zone is concentrated in the northwest part of the Heidimiao Sub-Depression, while the Nen-1 shale-oil-enriched zone lies in the northeast part. Full article

(This article belongs to the Topic Petroleum Geology and Geochemistry of Sedimentary Basins)

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32 pages, 26321 KiB

Open AccessArticle

Geochronology and Geochemical Characteristics of Granitoids in the Lesser Xing’an–Zhangguangcai Range: Petrogenesis and Implications for the Early Jurassic Tectonic Evolution of the Mudanjiang Ocean

by Jingui Kong, Kai Qiao, Xiaoyu Huo, Guobin Zhang, Xingkai Chen and Lei Yao

Minerals 2024, 14(9), 941; https://doi.org/10.3390/min14090941 - 15 Sep 2024

Abstract

This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed [...] Read more.

This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed during the late Early Jurassic period (182.9–177.2 Ma). Their geochemical characteristics and zircon saturation temperatures suggest that the granodiorites are moderately differentiated I-type granites and the monzonitic granite, granodioritic porphyries, and alkali feldspar granites are highly differentiated I-type granites. The degree of magma differentiation progressively increased from granodiorites to alkali feldspar granites. By combining the regional Nd and Hf isotope compositions, it was inferred that the magma source involved the melting of lower crustal material from the Mesoproterozoic to the Neoproterozoic eras. By integrating these findings with contemporaneous intrusive rock spatial variations, it was indicated that the late Early Jurassic granitoids in the Lesser Xing’an–Zhangguangcai Range formed within an extensional tectonic setting after the collision and closure of the Songnen–Zhangguangcai Range and Jiamusi blocks. Additionally, this study constrains the closure of the Mudanjiang Ocean to the late Early Jurassic period (177.2 Ma). Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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21 pages, 6955 KiB

Open AccessArticle

Zircon U-Pb Ages of the Granitoids in Shanxi and Its Significance for Tectonic Evolution of North China Craton in Mesozoic

by Fuhui Qi, Pengpeng Li and Chao Liu

Minerals 2024, 14(9), 940; https://doi.org/10.3390/min14090940 - 15 Sep 2024

Abstract

Mesozoic granitoid formations offer crucial insights into the tectonic history of the North China Craton. New zircon U-Pb ages of two Mesozoic granitoids in the Huai’an terrane yield ages of 226.4 ± 1.1 Ma for the Yihe (YH) granite and 156.3 ± 2.9 [...] Read more.

Mesozoic granitoid formations offer crucial insights into the tectonic history of the North China Craton. New zircon U-Pb ages of two Mesozoic granitoids in the Huai’an terrane yield ages of 226.4 ± 1.1 Ma for the Yihe (YH) granite and 156.3 ± 2.9 Ma for the Zhujiagou (ZJG) granodiorite. The negative Nb, Ta, and Ti anomalies; high Nb/Ta ratios (20.4 to 24.1); high (La/Yb)_N (30–84); low initial ⁸⁷Sr/⁸⁶Sr ratios (0.707725–0.708188); and negative Ɛ_Nd(t) values of the Yihe complex suggest that it originated from the partial melting of the lower crust and lithospheric mantle. However, the geochemical and Sr-Nd isotopic results of the ZJG granodiorite are characterized by I-type granites: Na₂O + K₂O values of 7.27 to 7.94 wt%, negative Nb anomalies, positive Pb anomalies, higher initial ⁸⁷Sr/⁸⁶Sr ratios (0.710979–0.714841), and much lower Ɛ_Nd(t) values (−27.1 to −30.1). The Late Jurassic Zhujiagou complex was derived from partial melting of a thickened low crust, and during the Late Triassic, magmatic rocks were formed under a post-collisional extensional regime. Multiple upwellings of the asthenosphere facilitated the mixing of magmas derived from partial melting of the lithospheric mantle and lower crust. These mixed magmas then ascended to the upper crust after undergoing fractional crystallization, leading to the formation of the YH complex. In the Late Jurassic, the tectonic regime of the NCC shifted from compression to extension. The Late Jurassic intrusion identified in this study developed within a compressional setting linked to the subduction of the Paleo-Pacific Ocean. Full article

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

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22 pages, 12371 KiB

Open AccessArticle

The Fate of “Immobile” Ti in Hyaloclastites: An Evidence from Silica–Iron-Rich Sedimentary Rocks of the Urals Paleozoic Massive Sulfide Deposits

by Nuriya R. Ayupova, Valery V. Maslennikov, Irina Yu. Melekestseva, Dmitry A. Artemyev and Elena V. Belogub

Minerals 2024, 14(9), 939; https://doi.org/10.3390/min14090939 - 13 Sep 2024

Abstract

The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor [...] Read more.

The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor metacolloidal TiO₂ phases to disordered anatase during seafloor alteration of hyaloclastites, which was later converted to globules and clusters and further to diagenetic rutile. The LA-ICP-MS analysis showed that the Ti content of hyaloclasts partly replaced by finely dispersed Si–Fe aggregates increases to 540–2950 ppm and decreases (<5 ppm) in full Si–Fe pseudomorphs after hyaloclasts. LA-ICP-MS element mapping reveals the enrichment in V, U, Cr, W, Nb, Pb, and Th of the anatase globules and the local accumulation of Zr, Y, and REE on their periphery. Corrosive biogenic textures in the outer zones of some hyaloclasts and biomorphic aggregates in rocks contain anatase particles in assemblage with apatite indicating the biophilic properties of Ti. This work fills the knowledge gaps about Ti mobilization during low-temperature seafloor alteration of hyaloclastites in VHMS deposits. Full article

(This article belongs to the Special Issue Mineralization and Geochemistry of VMS Deposits)

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13 pages, 4474 KiB

Open AccessArticle

Experimentation of Heat-Insulating Materials for Surrounding Rocks in Deep Mines and Simulation Study of Temperature Reduction

by Hongwei Deng and Yuanzhe Xiao

Minerals 2024, 14(9), 938; https://doi.org/10.3390/min14090938 - 13 Sep 2024

Abstract

With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with [...] Read more.

With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with different ratios were produced using tailings, P.O.32.5 clinker, aluminum powder, glass beads, quick lime, and slaked lime as test materials. Based on the uniaxial compression test, the thermal constant analysis test, and numerical simulation analysis technology, the change rule of mortar compressive strength and thermal conductivity was analyzed, and the cooling effect of surrounding-rock thermal insulation materials with different ratios was discussed. The results showed that the compressive strength of the surrounding-rock thermal insulation materials ranged from 0.39 to 0.53 MPa, and the thermal conductivity ranged from 0.261 to 0.387 W/(K·m), with the compressive strength of ratio E being the largest and the thermal conductivity of ratio A being the lowest. In the numerical simulation analysis results, the thermal insulation layer thickness was taken as a value of 10 cm when, at this time, the best thermal insulation effect and economic benefits involved a temperature reduction of 0.9 K. In the case of changing the thermal conductivity and inlet wind speed, the original temperature of the rock temperature reduction was also very clear, with maximum reductions of 0.92 K, 0.92 K, and 1.42 K. Full article

(This article belongs to the Special Issue Metallurgy Waste Used for Backfilling Materials)

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27 pages, 11927 KiB

Open AccessArticle

Nature of Scapolite Color: Ab Initio Calculations, Spectroscopy, and Structural Study

by Roman Shendrik, Nikita V. Chukanov, Alexander Bogdanov, Alexandra Myasnikova, Elizaveta Pankrushina, Anatoly A. Zolotarev, Anastasiia Babkina, Ekaterina Popova, Marina F. Vigasina, Sergey M. Aksenov, Grigoriy Ilyin and Igor V. Pekov

Minerals 2024, 14(9), 937; https://doi.org/10.3390/min14090937 - 13 Sep 2024

Abstract

The article describes the results of a comprehensive study of the extra-framework components of scapolites using quantum–chemical calculations, electronic and vibrational spectroscopy, and single-crystal X-ray diffraction and crystal structure refinement. The ab initio calculations were performed using an embedded-cluster approach of extra-framework components [...] Read more.

The article describes the results of a comprehensive study of the extra-framework components of scapolites using quantum–chemical calculations, electronic and vibrational spectroscopy, and single-crystal X-ray diffraction and crystal structure refinement. The ab initio calculations were performed using an embedded-cluster approach of extra-framework components in various cation surroundings. As a result, through comparing the experimental and ab initio calculation results, the energies of the electronic and vibrational transitions of various extra-framework components (CO₃)²⁻, (CO₃)^{$\cdot -$},

S_{3}^{\cdot -}

,

S_{2}^{\cdot -}

—as well as the role of these components in the process of the lowering of the symmetry—were determined for scapolites belonging to the marialite–meionite solid–solution series. The nature of the various colors of the scapolites has also been established. Colors from purple to blue are a result of the presence of radiation-induced pairs of defects: carbonate radical anions (CO₃)^{$\cdot -$} and F-centers. However, polysulfide

S_{3}^{\cdot -}

radical anions are found in some violet scapolites. Full article

(This article belongs to the Special Issue Crystal Structure, Mineralogy, and Geochemistry of Scapolite)

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24 pages, 13494 KiB

Open AccessArticle

Geology and Geochemistry of the Hongnipo Copper Deposit, Southwest China

by Wangdong Yang, Gongwen Wang and Yunchou Xu

Minerals 2024, 14(9), 936; https://doi.org/10.3390/min14090936 - 13 Sep 2024

Abstract

The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically [...] Read more.

The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically distributed gabbroic intrusions. Four stages of mineralization and alteration have been identified: sodic alteration (I), banded sulfide (II), magnetite (III), and sulfide vein/stockwork (IV). Extensive sodic alteration of stage I is confirmed by the composition of feldspars. Trace element analysis of magnetite suggests a formation temperature of 400 ± 50 °C and has a characteristic of IOCG deposits, while high δ¹⁸O values (8.3–11.0‰) of fluids from stage III indicate a magmatic water origin. Sulfide δ³⁴S_VCDT values from stages II and IV range from −2.6 to 10.9‰ and −1.5 to 9.9‰, respectively, suggesting a mixed sulfur source from magmatic H₂S and reduced seawater sulfate. Chalcopyrite from Hongnipo shows a narrow δ⁶⁵Cu range of −0.135 to 0.587‰, indicating formation at high temperatures. The lack of correlation between δ⁶⁵Cu and δ³⁴S_VCDT values suggests distinct geochemical behaviors in mineralization. In summary, the Hongnipo deposit is classified as a Cu-rich section of a typical IOCG deposit. Full article

(This article belongs to the Special Issue Geology, Geochemistry, Genesis, Modeling, Structure and Exploration of Copper Polymetallic Deposits)

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6 pages, 16630 KiB

Open AccessBrief Report

First Record of Romanechite in the Apulian Karst (Southern Italy) Resulting from the Interaction of Limestones and Clay Minerals

by Annamaria Fornelli, Francesca Micheletti, Pasquale Acquafredda and Annarosa Mangone

Minerals 2024, 14(9), 935; https://doi.org/10.3390/min14090935 - 13 Sep 2024

Abstract

A new occurrence of the Mn-Ba ore mineral, romanechite, has been discovered in a small paleo-doline of the Apulian karst on Mesozoic carbonate rock successions, characterized by reddish incrustations and nodules made essentially by Fe-bearing calcite. The conditions under which Mn-Ba ore minerals [...] Read more.

A new occurrence of the Mn-Ba ore mineral, romanechite, has been discovered in a small paleo-doline of the Apulian karst on Mesozoic carbonate rock successions, characterized by reddish incrustations and nodules made essentially by Fe-bearing calcite. The conditions under which Mn-Ba ore minerals form represent an intriguing area of research, as these minerals can act as scavengers for heavy elements, impacting soils, surface sediments, and even associated aquatic systems. The genesis of romanechite is linked to the progressive interaction of silicate aqueous solutions enriched in Al, Si, and Fe with the limestone substrate. The findings provide new insights into the genetic processes responsible for the formation of reddish Mn incrustations, supporting their polygenetic origin because of the chemical alteration of limestone and allochthonous siliciclastic muds. Full article

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

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13 pages, 14435 KiB

Open AccessArticle

Spread Spectrum Induced Polarization (SSIP) Survey for the Qiushuwan Copper–Molybdenum Deposits in Southern Henan Province, China

by Jawad Ahmad, Rujun Chen, Ijaz Ahmed, Muhammad Yaseen, Shahid Ali Shah, Osama Abdul Rahim, Farid Ullah, Shah Fahad and Li Rui

Minerals 2024, 14(9), 934; https://doi.org/10.3390/min14090934 - 13 Sep 2024

Abstract

The Qiushuwan Cu-Mo deposit, situated in the East Qinling molybdenum belt, is a notable mining site renowned for its considerable quantities of medium-sized molybdenum. The goal of this study is to improve comprehension and identify additional mineral resources by conducting a thorough examination [...] Read more.

The Qiushuwan Cu-Mo deposit, situated in the East Qinling molybdenum belt, is a notable mining site renowned for its considerable quantities of medium-sized molybdenum. The goal of this study is to improve comprehension and identify additional mineral resources by conducting a thorough examination of the mine using the spread spectrum-induced polarization (SSIP) technique. Gathering SSIP data, conducting geological investigations, and examining the electrical characteristics of rock and mineral samples along Profile-80 led to significant discoveries. The investigation identified two significant ore bodies with high conductivity: C2, linked to granite porphyry and molybdenum veins, and C4, associated with a skarn deposit containing a concentrated amount of copper ore. This study used resistivity models created from SSIP data to find out how conductivity changed in different parts of the research area. Additional drill verifications validated these findings, indicating the presence of potential mineral resources. The petrographic analysis of core samples showed that minerals like pyrite, molybdenite, chalcopyrite, epidote, calcite, and garnet were present. Notably, the samples frequently contained both pyrite and molybdenite together. Sample 04-2 contained substantial quantities of molybdenite and pyrite; Sample 05-1 had occasional pyrite; and Sample 07-4 included both pyrite and chalcopyrite. These findings offer useful insights for evaluating the magnitude and economic feasibility of the mineral deposits; however, additional investigation is required to completely comprehend the scope of the resources. The integration of borehole data and the alignment of geological sections with inversion models confirmed the validity of the conclusions. The core samples that were retrieved show a lot of different minerals, including valuable ores and minerals that have been changed. Pyrite and molybdenite are always found together. These findings establish a solid basis for further investigation and the sustainable management of resources. This study contributes to the understanding of the Qiushuwan Cu-Mo deposit and advances exploration techniques using the spread spectrum-induced polarization (SSIP) method. It provides useful information for geologists, mining professionals, and stakeholders involved in resource usage. Full article

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

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21 pages, 9535 KiB

Open AccessArticle

Petrogenesis of Eocene A-Type Granite Associated with the Yingpanshan–Damanbie Regolith-Hosted Ion-Adsorption Rare Earth Element Deposit in the Tengchong Block, Southwest China

by Zhong Tang, Zewei Pan, Tianxue Ming, Rong Li, Xiaohu He, Hanjie Wen and Wenxiu Yu

Minerals 2024, 14(9), 933; https://doi.org/10.3390/min14090933 - 12 Sep 2024

Abstract

The ion-adsorption-type rare earth element (iREE) deposits dominantly supply global resources of the heavy rare earth elements (HREEs), which have a critical role in a variety of advanced technological applications. The initial enrichment of REEs in the parent granites controls the formation of [...] Read more.

The ion-adsorption-type rare earth element (iREE) deposits dominantly supply global resources of the heavy rare earth elements (HREEs), which have a critical role in a variety of advanced technological applications. The initial enrichment of REEs in the parent granites controls the formation of iREE deposits. Many Mesozoic and Cenozoic granites are associated with iREE mineralization in the Tengchong block, Southwest China. However, it is unclear how vital the mineralogical and geochemical characteristics of these granites are to the formation of iREE mineralization. We conducted geochronology, geochemistry, and Hf isotope analyses of the Yingpanshan–Damanbie granitoids associated with the iREE deposit in the Tengchong block with the aims to discuss their petrogenesis and illustrate the process of the initial REE enrichment in the granites. The results showed that the Yingpanshan–Damanbie pluton consists of syenogranite and monzogranite, containing REE-bearing accessory minerals such as monazite, xenotime, apatite, zircon, allanite, and titanite, with a high REE concentration (210–626 ppm, mean value is 402 ppm). The parent granites have Zr + Nb + Ce + Y (333–747 ppm) contents and a high FeO^T/MgO ratio (5.89–11.4), and are enriched in Th (mean value of 43.6 ppm), U (mean value of 4.57 ppm), Zr (mean value of 305 ppm), Hf (mean value of 7.94 ppm), Rb (mean value of 198 ppm), K (mean value of 48,902 ppm), and have depletions of Sr (mean value of 188 ppm), Ba (mean value of 699 ppm), P (mean value of 586 ppm), Ti (mean value of 2757 ppm). The granites plot in the A-type area in FeO^T/MgO vs. Zr + Nb + Ce + Y and Zr vs. 10,000 Ga/Al diagrams, suggesting that they are A₂-type granites. These granites are believed to have formed through the partial melting of amphibolites at a post-collisional extension setting when the Tethys Ocean closed. REE-bearing minerals (e.g., apatite, titanite, allanite, and fluorite) and rock-forming minerals (e.g., potassium feldspar, plagioclase, biotite, muscovite) supply rare earth elements in weathering regolith for the Yingpanshan–Damanbie iREE deposit. Full article

(This article belongs to the Special Issue Petrogenesis of Large Igneous Province and Rare Earth–Rare Metal Deposits)

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23 pages, 10947 KiB

Open AccessReview

The Role of Organic Matter and Hydrocarbons in the Genesis of the Pb-Zn-Fe (Ba-Sr) Ore Deposits in the Diapirs Zone, Northern Tunisia

by Larbi Rddad, Nejib Jemmali and Samar Jaballah

Minerals 2024, 14(9), 932; https://doi.org/10.3390/min14090932 - 12 Sep 2024

Abstract

Extensional tectonics along NE-trending faults, coupled with diapirism, created paleo-highs and subsiding basins, providing the structural framework for subsequent mineralization processes. The preservation of organic matter within the Fahdene and Bahloul Cretaceous formations during the Anoxic Oceanic Events (AOE-1 and AOQ-2) facilitated the [...] Read more.

Extensional tectonics along NE-trending faults, coupled with diapirism, created paleo-highs and subsiding basins, providing the structural framework for subsequent mineralization processes. The preservation of organic matter within the Fahdene and Bahloul Cretaceous formations during the Anoxic Oceanic Events (AOE-1 and AOQ-2) facilitated the extraction of metals from seawater. The association of metals with organic matter, Fe-Mg oxides, and pyrite is revealed by principal component analysis (PCA). The subsequent maturation of organic matter generated hydrocarbons, with thermal cracking leading to the incorporation of organo-metallic ligands into mobile hydrocarbons. Oilfield brines form as a byproduct of this catagenesis. The metal-rich hydrocarbons and basinal brines invaded SO₄⁻²-rich fluids from Triassic evaporites, resulting in the precipitation of sulfates (barite and celestite) and the bacteriogenic (BSR) and/or thermal (TSR) reduction of sulfate to reduced sulfur, which combined with metals to form sulfide ores. This study examines the role of hydrocarbons in the genesis of ore deposits within the diapiric zone, drawing upon a synthesis of literature and geological data. It highlights the interplay between basinal evolution, the organic matter-rich Cretaceous formations (Fahdene and Bahloul), diapiric paleo-highs, and the Alpine orogeny, which are identified as crucial factors in ore genesis in the diapiric zone. Full article

(This article belongs to the Special Issue The Role of Hydrocarbons in the Genesis of Mineral Deposits)

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22 pages, 4005 KiB

Open AccessArticle

Distribution of Heavy Metals along the Mediterranean Shoreline from Baltim to El-Burullus (Egypt): Consequences for Possible Contamination

by Rehab A. Seif, Antoaneta Ene, Hesham M. H. Zakaly, Asmaa M. Sallam, Sherif A. Taalab, Mohammed S. Fnais, Diaa A. Saadawi, Shaimaa A. Amer and Hamdy A. Awad

Minerals 2024, 14(9), 931; https://doi.org/10.3390/min14090931 - 12 Sep 2024

Abstract

This work is mainly concerned with the effect of anthropogenic activities, the presence of black sand spots, factory construction, and shipping, in addition to other activities like agriculture, on soil heavy metal pollution along the Mediterranean shores of Lake El-Burullus, Egypt, to assess [...] Read more.

This work is mainly concerned with the effect of anthropogenic activities, the presence of black sand spots, factory construction, and shipping, in addition to other activities like agriculture, on soil heavy metal pollution along the Mediterranean shores of Lake El-Burullus, Egypt, to assess the contamination levels and to identify possible sources and the distribution of these metals. This study focuses on the various heavy metal contamination levels in El-Burullus Lake coastal sediments. Sediment samples were collected and analyzed by the XRF technique for heavy metals, including Cr, Cu, Ni, Zn, Zr, Pb, Ba, Sr, Ga, Rb, V, and Nb. Statistical analyses, including correlation coefficient, factor analysis, and cluster analysis, were employed to understand the interactions and sources of these metals. The highest concentrations recorded were for Zr (84–1436 mg/kg) and Pb (1–1166 mg/kg), with average concentrations of 455.53 mg/kg and 79.27 mg/kg, respectively. Cr, Zr, Nb, and Pb showed average values higher than the average shale concentration, indicating potential pollution. Correlation analysis revealed strong associations between several metals, suggesting common sources of both natural and anthropogenic origin and similar distribution patterns. Factor analysis indicated four main factors accounting for 94.069% of the total variance, with the first factor heavily dominated by Cr, Ni, Zn, and Ba. The contamination factor (Cf) and degree (DC) analyses revealed varying contamination levels, with most metals exhibiting the greatest values in the western half of the area. The pollution load index (PLI) indicated high-quality sediment samples without significant pollution. Our findings highlight the importance of continued monitoring and management techniques to reduce possible environmental and health concerns associated with these pollutants. Full article

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

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