Carla S. Valdivieso-Ramírez, Salomé Galeas, Marleny D. A. Saldaña, Patricia I. Pontón, Víctor H. Guerrero, Karla Vizuete, Alexis Debut, Bojan A. Marinkovic
Ferrous oxalate dihydrate is a versatile organic mineral with applications across fields. However, little is known about the feasibility of its synthesis directly from iron-bearing minerals using binary subcritical water (sCW) systems and its associated kinetics. In this study, the sCW+oxalic acid system at either 115 °C or 135 °C was investigated as a reaction medium for ferrous oxalate dihydrate (α-FeC2O4∙2H2O) synthesis, starting from ferrotitaniferous sands. The kinetics of the synthesis reaction were studied, and the physicochemical characterization of the as-synthetized ferrous oxalates was performed. Overall, the sCW synthesis was temperature-dependent, following second-order reaction kinetics according to the proposed precipitation pathway. A high reaction rate constant, significantly high yields (up to 89%), and reduced reaction times (2–8 h) were evident at 135 °C. The as-synthetized product corresponded to the monoclinic α-FeC2O4∙2H2O, showed relatively high specific surface areas (from 31.9 to 33.7 m2∙g−1), and exhibited band gap energies within the visible light range (~2.77 eV). These results suggest that α-FeC2O4∙2H2O can be synthesized using an organic dicarboxylic acid and iron-rich, widely available, low-cost mineral precursors. In addition, the as-prepared α-FeC2O4∙2H2O could be further optimized and tested for catalytic and visible light photocatalytic applications.
{"title":"Synthesis of Alpha Ferrous Oxalate Dihydrate from Ferrotitaniferous Mineral Sands via Hot Pressurized Aqueous Oxalic Acid: Kinetics and Characterization","authors":"Carla S. Valdivieso-Ramírez, Salomé Galeas, Marleny D. A. Saldaña, Patricia I. Pontón, Víctor H. Guerrero, Karla Vizuete, Alexis Debut, Bojan A. Marinkovic","doi":"10.3390/min14090891","DOIUrl":"https://doi.org/10.3390/min14090891","url":null,"abstract":"Ferrous oxalate dihydrate is a versatile organic mineral with applications across fields. However, little is known about the feasibility of its synthesis directly from iron-bearing minerals using binary subcritical water (sCW) systems and its associated kinetics. In this study, the sCW+oxalic acid system at either 115 °C or 135 °C was investigated as a reaction medium for ferrous oxalate dihydrate (α-FeC2O4∙2H2O) synthesis, starting from ferrotitaniferous sands. The kinetics of the synthesis reaction were studied, and the physicochemical characterization of the as-synthetized ferrous oxalates was performed. Overall, the sCW synthesis was temperature-dependent, following second-order reaction kinetics according to the proposed precipitation pathway. A high reaction rate constant, significantly high yields (up to 89%), and reduced reaction times (2–8 h) were evident at 135 °C. The as-synthetized product corresponded to the monoclinic α-FeC2O4∙2H2O, showed relatively high specific surface areas (from 31.9 to 33.7 m2∙g−1), and exhibited band gap energies within the visible light range (~2.77 eV). These results suggest that α-FeC2O4∙2H2O can be synthesized using an organic dicarboxylic acid and iron-rich, widely available, low-cost mineral precursors. In addition, the as-prepared α-FeC2O4∙2H2O could be further optimized and tested for catalytic and visible light photocatalytic applications.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"12 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shale formations globally are widely distributed with abundant resources and varied thermal maturation ranges. However, the understanding of shale’s oil generation peak, diagenetic stages, and pore evolution remains incomplete. This study investigates shale samples of varying maturities and organic matter content from representative oil and gas basins in China and the United States. Comprehensive characterization was conducted using thermal simulation, rock X-ray diffraction analysis, N2 and CO2 adsorption, and mercury injection analysis. The study delineates the hydrocarbon generation process in shale, identifies the oil generation threshold, determines the peak oil generation, and categorizes shale’s diagenetic stages based on clay minerals and pore evolution. The results indicate: (1) highly mature shale exhibits delayed hydrocarbon expulsion and peak oil generation, starting at Ro values greater than 0.75% and reaching peak oil generation at Ro levels surpassing 1.2%. In contrast, peak oil generation in less mature shale initiates at Ro values of 1.1%, providing a more precise depiction of the shale’s diagenetic evolution stages; (2) the higher the TOC content of shale, the greater its hydrocarbon generation capacity, showing a robust positive correlation between hydrocarbon generation and TOC; (3) the diagenesis and pore evolution of shale can be categorized into four distinct stages: the early diagenesis stage (Ro < 0.5%), dominated by mesopores, and with reduced pore volume and surface area; the middle diagenesis stage A (0.5%–1.1%), where shale pore volume has been enhanced while the surface area has been reduced; the middle diagenesis stage B (1.1%–2.0%), where an initial decrease followed by an increase in mesopore volume occurs, along with a modest increase in macropores; and the late diagenesis stage (Ro > 2.0%), with increased organic pores and microfractures, while both pore volume and surface area expand. The study suggests that a Ro of 1.1% marks the peak oil generation period for shale, occurring during the early stage of middle diagenesis, characterized by larger pore volume and surface area, crucial for shale oil and gas enrichment.
页岩层在全球分布广泛，资源丰富，热成熟范围各不相同。然而，人们对页岩的生油高峰、成岩阶段和孔隙演化的认识仍不全面。本研究调查了中国和美国具有代表性的油气盆地中不同成熟度和有机质含量的页岩样本。采用热模拟、岩石 X 射线衍射分析、N2 和 CO2 吸附以及注汞分析等方法进行了综合表征。研究划分了页岩中碳氢化合物的生成过程，确定了石油生成阈值，确定了石油生成峰值，并根据粘土矿物和孔隙演化划分了页岩的成岩阶段。结果表明：(1) 高度成熟页岩的碳氢化合物排出和石油生成峰值出现延迟，从 Ro 值大于 0.75% 开始，到 Ro 值超过 1.2% 时达到石油生成峰值。相比之下，成熟度较低的页岩在 Ro 值为 1.1% 时开始达到石油生成峰值，从而更精确地描述了页岩的成岩演化阶段；（2）页岩的 TOC 含量越高，其碳氢化合物生成能力就越强，这表明碳氢化合物生成与 TOC 之间存在很强的正相关性；（3）页岩的成岩和孔隙演化可分为四个不同的阶段：早期成岩阶段（Ro < 0.5%），以中孔为主，孔隙体积和表面积减小；成岩中期 A 阶段（0.5%-1.1%），页岩孔隙体积增大，表面积减小；成岩中期 B 阶段（1.1%-2.0%），中孔体积先减小后增大，大孔适度增加；成岩晚期（Ro > 2.0%），有机孔隙和微裂隙增加，孔隙体积和表面积扩大。研究表明，Ro 值为 1.1% 标志着页岩的产油高峰期，发生在成岩中期的早期阶段，其特点是孔隙体积和表面积增大，这对页岩油气的富集至关重要。
{"title":"New Advance in the Study of Shale Oil Generation Peak Determination and Diagenetic Pore Evolution","authors":"Haikun Su, Shaobin Guo","doi":"10.3390/min14090896","DOIUrl":"https://doi.org/10.3390/min14090896","url":null,"abstract":"Shale formations globally are widely distributed with abundant resources and varied thermal maturation ranges. However, the understanding of shale’s oil generation peak, diagenetic stages, and pore evolution remains incomplete. This study investigates shale samples of varying maturities and organic matter content from representative oil and gas basins in China and the United States. Comprehensive characterization was conducted using thermal simulation, rock X-ray diffraction analysis, N2 and CO2 adsorption, and mercury injection analysis. The study delineates the hydrocarbon generation process in shale, identifies the oil generation threshold, determines the peak oil generation, and categorizes shale’s diagenetic stages based on clay minerals and pore evolution. The results indicate: (1) highly mature shale exhibits delayed hydrocarbon expulsion and peak oil generation, starting at Ro values greater than 0.75% and reaching peak oil generation at Ro levels surpassing 1.2%. In contrast, peak oil generation in less mature shale initiates at Ro values of 1.1%, providing a more precise depiction of the shale’s diagenetic evolution stages; (2) the higher the TOC content of shale, the greater its hydrocarbon generation capacity, showing a robust positive correlation between hydrocarbon generation and TOC; (3) the diagenesis and pore evolution of shale can be categorized into four distinct stages: the early diagenesis stage (Ro < 0.5%), dominated by mesopores, and with reduced pore volume and surface area; the middle diagenesis stage A (0.5%–1.1%), where shale pore volume has been enhanced while the surface area has been reduced; the middle diagenesis stage B (1.1%–2.0%), where an initial decrease followed by an increase in mesopore volume occurs, along with a modest increase in macropores; and the late diagenesis stage (Ro > 2.0%), with increased organic pores and microfractures, while both pore volume and surface area expand. The study suggests that a Ro of 1.1% marks the peak oil generation period for shale, occurring during the early stage of middle diagenesis, characterized by larger pore volume and surface area, crucial for shale oil and gas enrichment.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elias Kevrekidis, Stavros Savvas Triantafyllidis, Stylianos Fotios Tombros, Sotirios Kokkalas, Joan Papavasiliou, Konstantinos Kappis, Konstantinos Papageorgiou, Ioannis Koukouvelas, Michalis Fitros, Dimitrios Zouzias, Panagiotis Voudouris, Degao Zhai, Karen St Seymour
The concealed Molai Zn-Pb±(Ag,Ge) stratiform deposit in southeastern Peloponnese is hosted in Triassic intermediate tuffs, ignimbrites and subaerial andesitic flows. The host rocks display trace element signatures of a Supra-Subduction Zone (SSZ) setting. Three ore-forming stages are recognized, with stages I and II related to formation of the epigenetic, stratiform, massive-to-semi-massive ore and a late stage III associated with vein-type mineralization. The O and D isotope geochemistry of gangue chlorite and epidote reveal mixing with fresh meteoric water during the weaning stages of the hydrothermal activity of the late stage II due to uplifting of the hydrothermal system. Sphalerite is the major ore phase, with three different varieties formed during stages I (Sp-I) and II (Sp-II and Sp-III). All sphalerite varieties coexist, depicting gradual change in the chemistry of the ore-forming fluids. Molai ores are characterized by elevated Ag and Ge contents. Tetrahedrite is the major Ag carrier, while among the three sphalerite varieties, early Sp-I comprises the highest Ge contents. The Molai Zn-Pb±(Ag,Ge) deposit is characterized by intermediate features between bimodal felsic massive sulfides and subaerial epithermal systems based on the shallow formation depth, the presence of hydraulic breccias associated with phase separation, the ore formation along high-angle faults, the relatively low ore-forming temperatures below 250 °C obtained from geothermometry, and the absence of the typical structure of bimodal felsic type ores.
伯罗奔尼撒半岛东南部隐蔽的莫莱锌-铅±（银、锗）层状矿床赋存于三叠纪中间凝灰岩、火成岩和次生安山岩流中。母岩显示了超俯冲带（SSZ）环境的微量元素特征。矿石形成分为三个阶段，第一和第二阶段与表生、层状、块状到半块状矿石的形成有关，第三阶段后期与脉状矿化有关。煤矸石绿泥石和闪石的 O 和 D 同位素地球化学显示，在晚期第二阶段热液活动的断乳期，由于热液系统的隆起，煤矸石绿泥石和闪石与新鲜的陨石水混合。闪锌矿是主要的矿相，在第一阶段（Sp-I）和第二阶段（Sp-II 和 Sp-III）形成了三种不同的品种。所有闪锌矿品种共存，表明成矿流体的化学性质在逐渐变化。莫莱矿石的特点是银和锗含量较高。四面体是主要的银载体，而在三个闪锌矿品种中，早期 Sp-I 的 Ge 含量最高。莫莱锌-铅±（银、锗）矿床的特点是介于双峰长晶块状硫化物和次生表生系统之间，其依据是形成深度较浅、存在与相分离相关的水力角砾岩、矿石沿高角度断层形成、地温测量得到的矿石形成温度相对较低，低于 250 °C，以及不存在双峰长晶型矿石的典型结构。
{"title":"Revisiting the Concealed Zn-Pb±(Ag,Ge) VMS-Style Ore Deposit, Molai, Southeastern Peloponnese, Greece","authors":"Elias Kevrekidis, Stavros Savvas Triantafyllidis, Stylianos Fotios Tombros, Sotirios Kokkalas, Joan Papavasiliou, Konstantinos Kappis, Konstantinos Papageorgiou, Ioannis Koukouvelas, Michalis Fitros, Dimitrios Zouzias, Panagiotis Voudouris, Degao Zhai, Karen St Seymour","doi":"10.3390/min14090885","DOIUrl":"https://doi.org/10.3390/min14090885","url":null,"abstract":"The concealed Molai Zn-Pb±(Ag,Ge) stratiform deposit in southeastern Peloponnese is hosted in Triassic intermediate tuffs, ignimbrites and subaerial andesitic flows. The host rocks display trace element signatures of a Supra-Subduction Zone (SSZ) setting. Three ore-forming stages are recognized, with stages I and II related to formation of the epigenetic, stratiform, massive-to-semi-massive ore and a late stage III associated with vein-type mineralization. The O and D isotope geochemistry of gangue chlorite and epidote reveal mixing with fresh meteoric water during the weaning stages of the hydrothermal activity of the late stage II due to uplifting of the hydrothermal system. Sphalerite is the major ore phase, with three different varieties formed during stages I (Sp-I) and II (Sp-II and Sp-III). All sphalerite varieties coexist, depicting gradual change in the chemistry of the ore-forming fluids. Molai ores are characterized by elevated Ag and Ge contents. Tetrahedrite is the major Ag carrier, while among the three sphalerite varieties, early Sp-I comprises the highest Ge contents. The Molai Zn-Pb±(Ag,Ge) deposit is characterized by intermediate features between bimodal felsic massive sulfides and subaerial epithermal systems based on the shallow formation depth, the presence of hydraulic breccias associated with phase separation, the ore formation along high-angle faults, the relatively low ore-forming temperatures below 250 °C obtained from geothermometry, and the absence of the typical structure of bimodal felsic type ores.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"63 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Moment representations have been proposed to facilitate the interpretation of geophysical time domain electromagnetic responses. We present a new methodology for estimating these moments from field data for different system waveforms when on-time and off-time measurements are available. Quadrature impulse response moments are estimated by a recursive relation involving moments of the input waveform and moments of the observed response. After adapting this method to time domain electromagnetic applications—in particular, MEGATEM and AeroTEM (AirTEM) airborne electromagnetic systems—we present the results from applying this method on synthetic and real data collected over the Reid–Mahaffy test site in northern Ontario, Canada.
{"title":"Moment Estimation from Time Domain Electromagnetic Data","authors":"Marc A. Vallée, Mouhamed Moussaoui","doi":"10.3390/min14090888","DOIUrl":"https://doi.org/10.3390/min14090888","url":null,"abstract":"Moment representations have been proposed to facilitate the interpretation of geophysical time domain electromagnetic responses. We present a new methodology for estimating these moments from field data for different system waveforms when on-time and off-time measurements are available. Quadrature impulse response moments are estimated by a recursive relation involving moments of the input waveform and moments of the observed response. After adapting this method to time domain electromagnetic applications—in particular, MEGATEM and AeroTEM (AirTEM) airborne electromagnetic systems—we present the results from applying this method on synthetic and real data collected over the Reid–Mahaffy test site in northern Ontario, Canada.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"9 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xueling Dai, Ke Chen, Junke Zhang, Yongshun Li, Mingpeng He, Zhongfa Liu
The Baoshan Cu-Pb-Zn deposit is situated at the intersection of the Qin-Hang Cu polymetallic and Nanling W-Sn polymetallic metallogenic belts. The age, lithology, petrogenesis, and tectonic setting of granodiorite porphyry within the deposit remain subjects of debate. Additionally, there is a lack of comparative studies with the W-Sn-related granites in the region. This study conducted whole-rock major and trace element analysis, Sr-Nd isotope analysis, and zircon U-Pb dating on the Baoshan granodiorite porphyry. The zircon U-Pb age of the granodiorite porphyry is 162 ± 1 Ma. The whole-rock SiO2 and K2O contents range from 65.87 to 68.21 wt.% and 3.42 to 5.62 wt.%, respectively, indicating that the granodiorite porphyry belongs to high-potassium calc-alkaline I-type granite. The granodiorite porphyry is characterized by enrichment in LREE and depletion in HREE (LREE/HREE ratio = 6.2–21.2). The samples of granodiorite porphyry generally exhibit weak negative Eu anomalies or no Eu anomalies (δEu = 0.62–1.04, mean = 0.82). The (87Sr/86Sr)i and εNd(t) values are 0.707717–0.709506 and −7.54 to −4.87, respectively. The whole-rock geochemical composition and Sr-Nd isotopic values indicate that the magma originated from the partial melting of the Mesoproterozoic ancient crust and Neoproterozoic mafic juvenile lower crust, with the addition of high oxygen fugacity and water-rich lithospheric mantle melts. The source of the granodiorite porphyry in the Baoshan deposit is significantly different from the crust-derived metapelite source of the W-Sn-related granite in the area, indicating that different magma sources might be the main reason for the co-spatial and nearly contemporaneous development of Cu-Pb-Zn and W-Sn mineralization in the southern Hunan region.
{"title":"Geochronology and Geochemistry of Granodiorite Porphyry in the Baoshan Cu-Pb-Zn Deposit, South China: Insights into Petrogenesis and Metallogeny","authors":"Xueling Dai, Ke Chen, Junke Zhang, Yongshun Li, Mingpeng He, Zhongfa Liu","doi":"10.3390/min14090897","DOIUrl":"https://doi.org/10.3390/min14090897","url":null,"abstract":"The Baoshan Cu-Pb-Zn deposit is situated at the intersection of the Qin-Hang Cu polymetallic and Nanling W-Sn polymetallic metallogenic belts. The age, lithology, petrogenesis, and tectonic setting of granodiorite porphyry within the deposit remain subjects of debate. Additionally, there is a lack of comparative studies with the W-Sn-related granites in the region. This study conducted whole-rock major and trace element analysis, Sr-Nd isotope analysis, and zircon U-Pb dating on the Baoshan granodiorite porphyry. The zircon U-Pb age of the granodiorite porphyry is 162 ± 1 Ma. The whole-rock SiO2 and K2O contents range from 65.87 to 68.21 wt.% and 3.42 to 5.62 wt.%, respectively, indicating that the granodiorite porphyry belongs to high-potassium calc-alkaline I-type granite. The granodiorite porphyry is characterized by enrichment in LREE and depletion in HREE (LREE/HREE ratio = 6.2–21.2). The samples of granodiorite porphyry generally exhibit weak negative Eu anomalies or no Eu anomalies (δEu = 0.62–1.04, mean = 0.82). The (87Sr/86Sr)i and εNd(t) values are 0.707717–0.709506 and −7.54 to −4.87, respectively. The whole-rock geochemical composition and Sr-Nd isotopic values indicate that the magma originated from the partial melting of the Mesoproterozoic ancient crust and Neoproterozoic mafic juvenile lower crust, with the addition of high oxygen fugacity and water-rich lithospheric mantle melts. The source of the granodiorite porphyry in the Baoshan deposit is significantly different from the crust-derived metapelite source of the W-Sn-related granite in the area, indicating that different magma sources might be the main reason for the co-spatial and nearly contemporaneous development of Cu-Pb-Zn and W-Sn mineralization in the southern Hunan region.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"13 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdelrhman Fahmy, Eduardo Molina-Piernas, Salvador Domínguez-Bella
The Karnak Temples complex, a monumental site dating back to approximately 1970 BC, faces significant preservation challenges due to a confluence of mechanical, environmental, and anthropogenic factors impacting its stone blocks. This study provides a comprehensive evaluation of the deterioration affecting the northeast corner of the complex, revealing that the primary forms of damage include split cracking and fracturing. Seismic activities have induced out-of-plane displacements, fractures, and chipping, while flooding has worsened structural instability through uplift and prolonged water exposure. Soil liquefaction and fluctuating groundwater levels have exacerbated the misalignment and embedding of stone blocks. Thermal stress and wind erosion have caused microstructural decay and surface degradation and contaminated water sources have led to salt weathering and chemical alterations. Multi-temporal satellite imagery has revealed the influence of vegetation, particularly invasive plant species, on physical and biochemical damage to the stone. This study utilized in situ assessments to document damage patterns and employed satellite imagery to assess environmental impacts, providing a multi-proxy approach to understanding the current state of the stone blocks. This analysis highlights the urgent need for a multi-faceted conservation strategy. Recommendations include constructing elevated platforms from durable materials to reduce soil and water contact, implementing non-invasive cleaning and consolidation techniques, and developing effective water management and contamination prevention measures. Restoration should focus on repairing severely affected blocks with historically accurate materials and establishing an open museum setting will enhance public engagement. Long-term preservation will benefit from regular monitoring using 3D scanning and a preventive conservation schedule. Future research should explore non-destructive testing and interdisciplinary collaboration to refine conservation strategies and ensure the sustained protection of this invaluable historical heritage.
{"title":"Conservation Assessment of the Stone Blocks in the Northeast Corner of the Karnak Temples in Luxor, Egypt","authors":"Abdelrhman Fahmy, Eduardo Molina-Piernas, Salvador Domínguez-Bella","doi":"10.3390/min14090890","DOIUrl":"https://doi.org/10.3390/min14090890","url":null,"abstract":"The Karnak Temples complex, a monumental site dating back to approximately 1970 BC, faces significant preservation challenges due to a confluence of mechanical, environmental, and anthropogenic factors impacting its stone blocks. This study provides a comprehensive evaluation of the deterioration affecting the northeast corner of the complex, revealing that the primary forms of damage include split cracking and fracturing. Seismic activities have induced out-of-plane displacements, fractures, and chipping, while flooding has worsened structural instability through uplift and prolonged water exposure. Soil liquefaction and fluctuating groundwater levels have exacerbated the misalignment and embedding of stone blocks. Thermal stress and wind erosion have caused microstructural decay and surface degradation and contaminated water sources have led to salt weathering and chemical alterations. Multi-temporal satellite imagery has revealed the influence of vegetation, particularly invasive plant species, on physical and biochemical damage to the stone. This study utilized in situ assessments to document damage patterns and employed satellite imagery to assess environmental impacts, providing a multi-proxy approach to understanding the current state of the stone blocks. This analysis highlights the urgent need for a multi-faceted conservation strategy. Recommendations include constructing elevated platforms from durable materials to reduce soil and water contact, implementing non-invasive cleaning and consolidation techniques, and developing effective water management and contamination prevention measures. Restoration should focus on repairing severely affected blocks with historically accurate materials and establishing an open museum setting will enhance public engagement. Long-term preservation will benefit from regular monitoring using 3D scanning and a preventive conservation schedule. Future research should explore non-destructive testing and interdisciplinary collaboration to refine conservation strategies and ensure the sustained protection of this invaluable historical heritage.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"59 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The management of mine tailings presents a global challenge. Re-mining these tailings to recover remaining metals could play a crucial role in reducing the volume of stored tailings, as historical mining methods were less efficient than those used today. Consequently, mine wastes have the potential to become unconventional resources for critical minerals. To assess this potential, critical minerals and metals in the mine tailings were investigated through sampling, characterization, and 3D geostatistical modeling. The Bleïda copper mine tailings in Morocco were modeled, and residual copper resources were estimated using ordinary kriging (OK). Tailings were systematically sampled at a depth of 1.8 m using a triangular grid and tubing method. The metallic and mineralogical content of the samples was analyzed, and a numerical 3D model of the tailing’s facility was created using topographic drone surveys, geochemical data, and geostatistical modeling. The results from the 3D block model of the Bleïda tailings facility reveal that the volume of deposited tailings is 3.73 million cubic meters (mm3), equivalent to 4.85 million tonnes (Mt). Furthermore, based on the average copper grade (~0.3% by weight) in the studied part of the tailings pond, the copper resources are estimated at 2760 tonnes. Mineralogical characterization indicates that this metallic content is mainly associated with sulfide and carbonate minerals, which exhibit a low degree of liberation. This study aims to serve as a reference for assessing the reprocessing feasibility of tailings in both abandoned and active mines, thereby contributing to the sustainable management of mine tailings facilities. Geostatistical modeling has proven effective in producing tonnage estimates for tailings storage facilities and should be adopted by the industry to reduce the technical and financial uncertainties associated with re-mining.
{"title":"3D Geostatistical Modeling and Metallurgical Investigation of Cu in Tailings Deposit: Characterization and Assessment of Potential Resources","authors":"M’hamed Koucham, Yassine Ait-Khouia, Saâd Soulaimani, Mariam El-Adnani, Abdessamad Khalil","doi":"10.3390/min14090893","DOIUrl":"https://doi.org/10.3390/min14090893","url":null,"abstract":"The management of mine tailings presents a global challenge. Re-mining these tailings to recover remaining metals could play a crucial role in reducing the volume of stored tailings, as historical mining methods were less efficient than those used today. Consequently, mine wastes have the potential to become unconventional resources for critical minerals. To assess this potential, critical minerals and metals in the mine tailings were investigated through sampling, characterization, and 3D geostatistical modeling. The Bleïda copper mine tailings in Morocco were modeled, and residual copper resources were estimated using ordinary kriging (OK). Tailings were systematically sampled at a depth of 1.8 m using a triangular grid and tubing method. The metallic and mineralogical content of the samples was analyzed, and a numerical 3D model of the tailing’s facility was created using topographic drone surveys, geochemical data, and geostatistical modeling. The results from the 3D block model of the Bleïda tailings facility reveal that the volume of deposited tailings is 3.73 million cubic meters (mm3), equivalent to 4.85 million tonnes (Mt). Furthermore, based on the average copper grade (~0.3% by weight) in the studied part of the tailings pond, the copper resources are estimated at 2760 tonnes. Mineralogical characterization indicates that this metallic content is mainly associated with sulfide and carbonate minerals, which exhibit a low degree of liberation. This study aims to serve as a reference for assessing the reprocessing feasibility of tailings in both abandoned and active mines, thereby contributing to the sustainable management of mine tailings facilities. Geostatistical modeling has proven effective in producing tonnage estimates for tailings storage facilities and should be adopted by the industry to reduce the technical and financial uncertainties associated with re-mining.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ingrid W. Hadlich, Artur C. Bastos Neto, Vitor P. Pereira, Harald G. Dill, Nilson F. Botelho
This study focuses on the relationship between U and pyrochlore in the world-class Sn-Nb-Ta (U, Th, REE, Li) Madeira deposit within the Pitinga mining district of northern Brazil. The primary U mineralization is of intrusive-type and early magmatic origin, hosted in the peralkaline albite-enriched granite facies of the A-type Madeira granite (~1820 Ma). U-Pb-LREE-enriched pyrochlore is the only primary U ore and is widely and homogeneously dispersed in two albite-enriched granite subfacies: the albite-enriched granite core (AGC) and the albite-enriched granite border (AGB). In both zones, the pyrochlore crystals underwent strong hydrothermal alteration by F-rich, low-temperature aqueous fluids. During this hypogene alteration process, cations such as LREE, Nb, and F were selectively released, while others like Fe and Si were introduced. This led to the successive formation of various secondary pyrochlore varieties and a relative enrichment of U (up to 13.73 wt.% UO2). The alteration of pyrochlore eventually resulted in the breakdown of its structure, leading to the formation of U-bearing columbite pseudomorphs and the precipitation of U-rich silicates (up to 34.35 wt.% UO2), galena, and LREE-rich fluorides within pyrochlore vugs. In contrast to the homogeneous distribution of the primary ore mineralization, the secondary pyrochlore mineralization shows striking zonation, being most intense in the AGB and AGC proximal to a massive cryolite deposit. The U mineralization in the Madeira deposit exhibits grades of 328 ppm UO2, comparable to the main deposits of this type, with significant reserves of up to 52 kt U. However, it is different from those deposits in four key aspects: homogeneous dispersion of mineralization; pyrochlore as the exclusive primary ore mineral; U and Th mineralizations formed at different stages; and intense hydrothermal alteration. These characteristics are attributed to the special conditions imposed by the fluorine-rich nature of the peralkaline magma.
本研究的重点是巴西北部 Pitinga 矿区世界级的马德拉锡铌钽（U、Th、REE、Li）矿床中铀和火成岩之间的关系。原生铀矿化属于侵入型早期岩浆成因，赋存于 A 型马德拉花岗岩的围岩白云石富集花岗岩层中（约 1820 Ma）。富含 U-Pb-LREE 的火成岩是唯一的原生铀矿石，广泛而均匀地分布在两个白云石富集花岗岩亚岩层中：白云石富集花岗岩岩芯（AGC）和白云石富集花岗岩边界（AGB）。在这两个区域，火成岩晶体在富含 F 的低温水性流体的作用下发生了强烈的热液蚀变。在这个低温蚀变过程中，LREE、Nb 和 F 等阳离子被选择性地释放出来，而 Fe 和 Si 等其他阳离子则被引入。这导致了各种次生火成岩的相继形成和铀的相对富集（最高达 13.73 wt.% UO2）。辉绿岩的蚀变最终导致了其结构的破坏，形成了含铀的铌铁矿假象，并在辉绿岩岩体中析出了富含铀的硅酸盐（最高达 34.35 wt.% UO2）、方铅矿和富含 LREE 的氟化物。与原生矿成矿作用的均匀分布不同，次生辉绿岩成矿作用呈现出明显的分带现象，在靠近块状冰晶石矿床的 AGB 和 AGC 地区最为强烈。马德拉矿床的铀矿化品位为百万分之 328，与该类型的主要矿床相当，储量高达 52 千吨铀。然而，该矿床与这些矿床的不同之处主要体现在四个方面：矿化均匀分布；辉绿岩是唯一的原生矿石矿物；铀和钍矿化形成于不同阶段；热液蚀变强烈。这些特点归因于碱性岩浆富含氟的特殊条件。
{"title":"The Radioactive Rare Metal Mineralization in the World-Class Sn-Nb-Ta-U-Th-REE-Deposit Madeira (Pitinga, Amazonas State, Brazil): With Special Reference to the Complex Alteration of Pyrochlore-Group Minerals","authors":"Ingrid W. Hadlich, Artur C. Bastos Neto, Vitor P. Pereira, Harald G. Dill, Nilson F. Botelho","doi":"10.3390/min14090895","DOIUrl":"https://doi.org/10.3390/min14090895","url":null,"abstract":"This study focuses on the relationship between U and pyrochlore in the world-class Sn-Nb-Ta (U, Th, REE, Li) Madeira deposit within the Pitinga mining district of northern Brazil. The primary U mineralization is of intrusive-type and early magmatic origin, hosted in the peralkaline albite-enriched granite facies of the A-type Madeira granite (~1820 Ma). U-Pb-LREE-enriched pyrochlore is the only primary U ore and is widely and homogeneously dispersed in two albite-enriched granite subfacies: the albite-enriched granite core (AGC) and the albite-enriched granite border (AGB). In both zones, the pyrochlore crystals underwent strong hydrothermal alteration by F-rich, low-temperature aqueous fluids. During this hypogene alteration process, cations such as LREE, Nb, and F were selectively released, while others like Fe and Si were introduced. This led to the successive formation of various secondary pyrochlore varieties and a relative enrichment of U (up to 13.73 wt.% UO2). The alteration of pyrochlore eventually resulted in the breakdown of its structure, leading to the formation of U-bearing columbite pseudomorphs and the precipitation of U-rich silicates (up to 34.35 wt.% UO2), galena, and LREE-rich fluorides within pyrochlore vugs. In contrast to the homogeneous distribution of the primary ore mineralization, the secondary pyrochlore mineralization shows striking zonation, being most intense in the AGB and AGC proximal to a massive cryolite deposit. The U mineralization in the Madeira deposit exhibits grades of 328 ppm UO2, comparable to the main deposits of this type, with significant reserves of up to 52 kt U. However, it is different from those deposits in four key aspects: homogeneous dispersion of mineralization; pyrochlore as the exclusive primary ore mineral; U and Th mineralizations formed at different stages; and intense hydrothermal alteration. These characteristics are attributed to the special conditions imposed by the fluorine-rich nature of the peralkaline magma.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"19 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The buried hills of the Archean metamorphic rocks in the Bozhong Depression of the Bohai Bay Basin are the main gas-bearing strata, with burial depths ranging from 4000 m to 5500 m. However, metamorphic rocks have internal structural characteristics, such as diverse mineral components, oriented arrangement of mineral particles, complex pore connectivity, variable crystal structures, orthogonal development of multiple sets of fractures, and uneven fluid filling. Compared with conventional reservoirs, they have obvious heterogeneity and anisotropy characteristics. Traditional rock physics modeling methods are no longer suitable for predicting the elastic and anisotropic parameters of metamorphic reservoirs. Therefore, we introduced a vector mixed random medium model to calculate the effect of the oriented arrangement of metamorphic rock minerals on the modulus of the rock matrix and introduced a metamorphic factor to describe the impact of metamorphic recrystallization and alteration metasomatism on the elastic modulus of the rock matrix. Practical applications have shown that the new, improved rock physics modeling method can better estimate the S-wave velocity and anisotropy parameters in wells compared to traditional rock physics modeling methods, providing a reliable basis for predicting fractured reservoirs in metamorphic rock at buried hills.
{"title":"A Rock Physics Modeling Method for Metamorphic Rock Reservoirs in Buried Hill","authors":"Hongjian Hao, Guangzhi Zhang, You Zhou","doi":"10.3390/min14090892","DOIUrl":"https://doi.org/10.3390/min14090892","url":null,"abstract":"The buried hills of the Archean metamorphic rocks in the Bozhong Depression of the Bohai Bay Basin are the main gas-bearing strata, with burial depths ranging from 4000 m to 5500 m. However, metamorphic rocks have internal structural characteristics, such as diverse mineral components, oriented arrangement of mineral particles, complex pore connectivity, variable crystal structures, orthogonal development of multiple sets of fractures, and uneven fluid filling. Compared with conventional reservoirs, they have obvious heterogeneity and anisotropy characteristics. Traditional rock physics modeling methods are no longer suitable for predicting the elastic and anisotropic parameters of metamorphic reservoirs. Therefore, we introduced a vector mixed random medium model to calculate the effect of the oriented arrangement of metamorphic rock minerals on the modulus of the rock matrix and introduced a metamorphic factor to describe the impact of metamorphic recrystallization and alteration metasomatism on the elastic modulus of the rock matrix. Practical applications have shown that the new, improved rock physics modeling method can better estimate the S-wave velocity and anisotropy parameters in wells compared to traditional rock physics modeling methods, providing a reliable basis for predicting fractured reservoirs in metamorphic rock at buried hills.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"97 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natalia Vidal de la Peña, Séverine Marquis, Stéphane Jacques, Elise Aubry, Grégoire Léonard, Dominique Toye
The construction sector is among the most polluting industries globally, accounting for approximately 37.5% of the European Union’s total waste generation in 2020. Therefore, it is imperative to develop strategies to enhance the sustainability of this sector. This paper proposes a multiscale COMSOL Multiphysics numerical model for an ex situ mineral carbonation process of hydrated lime. The carbonation process is characterized at both the micro- and macroscale levels, encompassing interactions within and between the particles. This model incorporates both reaction and diffusion phenomena, considering the effects of porosity and liquid-water saturation parameters. Generally, liquid-water saturation enhances the reaction kinetics but not CO2 diffusion, while porosity improves CO2 diffusion throughout the granular bed. The model has been experimentally validated, showing promising results by accurately characterizing carbonation tendencies and the influence of the CO2 flow rate and the initial water-to-solid ratio on the carbonation process. The proposed mathematical model facilitates the study of various parameters, including particle radius, reactor geometry, and material porosity. This analysis is valuable for both current and future projects, as it aims to identify the most profitable configurations for the hydrated lime carbonation process.
{"title":"A Mathematical Model for Enhancing CO2 Capture in Construction Sector Using Hydrated Lime","authors":"Natalia Vidal de la Peña, Séverine Marquis, Stéphane Jacques, Elise Aubry, Grégoire Léonard, Dominique Toye","doi":"10.3390/min14090889","DOIUrl":"https://doi.org/10.3390/min14090889","url":null,"abstract":"The construction sector is among the most polluting industries globally, accounting for approximately 37.5% of the European Union’s total waste generation in 2020. Therefore, it is imperative to develop strategies to enhance the sustainability of this sector. This paper proposes a multiscale COMSOL Multiphysics numerical model for an ex situ mineral carbonation process of hydrated lime. The carbonation process is characterized at both the micro- and macroscale levels, encompassing interactions within and between the particles. This model incorporates both reaction and diffusion phenomena, considering the effects of porosity and liquid-water saturation parameters. Generally, liquid-water saturation enhances the reaction kinetics but not CO2 diffusion, while porosity improves CO2 diffusion throughout the granular bed. The model has been experimentally validated, showing promising results by accurately characterizing carbonation tendencies and the influence of the CO2 flow rate and the initial water-to-solid ratio on the carbonation process. The proposed mathematical model facilitates the study of various parameters, including particle radius, reactor geometry, and material porosity. This analysis is valuable for both current and future projects, as it aims to identify the most profitable configurations for the hydrated lime carbonation process.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"26 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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