Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
Showing 1 - 42 of 42 Journals sorted alphabetically
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 2)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 2)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
CIM Journal     Hybrid Journal  
Clay Minerals     Hybrid Journal   (Followers: 8)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 11)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 2)
European Journal of Mineralogy     Hybrid Journal   (Followers: 12)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 1)
Geology of Ore Deposits     Hybrid Journal   (Followers: 3)
Geomaterials     Open Access   (Followers: 2)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 8)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal  
International Journal of Coal Geology     Hybrid Journal   (Followers: 3)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 2)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 14)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 9)
International Journal of Mining and Geo-Engineering     Open Access  
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 5)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 5)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 4)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 6)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access   (Followers: 1)
Journal of Applied Geophysics     Hybrid Journal   (Followers: 15)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 4)
Journal of Geology and Mining Research     Open Access   (Followers: 11)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 8)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 15)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 2)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 5)
Journal of Sustainable Mining     Open Access   (Followers: 3)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 5)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 3)
Lithos     Hybrid Journal   (Followers: 9)
Mine Water and the Environment     Hybrid Journal   (Followers: 5)
Mineral Economics     Hybrid Journal  
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 11)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 4)
Mineralium Deposita     Hybrid Journal   (Followers: 4)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 2)
Minerals     Open Access  
Minerals & Energy - Raw Materials Report     Hybrid Journal  
Minerals Engineering     Hybrid Journal   (Followers: 9)
Mining Engineering     Full-text available via subscription   (Followers: 5)
Mining Journal     Full-text available via subscription   (Followers: 3)
Mining Report     Hybrid Journal   (Followers: 2)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 2)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 8)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 1)
Réalités industrielles     Full-text available via subscription  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 4)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 7)
Rocks & Minerals     Hybrid Journal   (Followers: 2)
Rudarsko-geološko-naftni Zbornik     Open Access  
Stainless Steel World     Full-text available via subscription   (Followers: 17)
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
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Journal Prestige (SJR): 0.462
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ISSN (Online) 2075-163X
Published by MDPI Homepage  [84 journals]
  • Minerals, Vol. 12, Pages 680: Natural Source Electromagnetic Component
           Exploration of Coalbed Methane Reservoirs

    • Authors: Nan Wang, Qiming Qin
      First page: 680
      Abstract: As an environmentally friendly and high-calorific natural gas, coalbed methane (CBM) has become one of the world’s most crucial unconventional energy sources. Undoubtedly, it is necessary to conduct in-depth research on reservoir exploration methods to ensure high and stable CBM production in the development stage. However, current methods have disadvantages such as high cost, complex devices, and poor terrain adaptability, and therefore they are unsuitable for reasonable monitoring of CBM reservoirs. In contrast, electromagnetic prospecting methods are increasingly widely employed in the rapid delineation of conductive distributions, contributing a lot to in-situ reservoir interpretation. Furthermore, a natural source Super-Low Frequency electromagnetic component method (i.e., the SLF method for short) has been proposed and applied with high potential in a CBM enrichment area, Qinshui Basin, China. In this paper, this method is thoroughly discussed. The magnetic component responses of the SLF method can be used as the characteristic responses of subsurface layers, and the forward modeling algorithms using the finite element method have been successfully developed and verified. On this basis, the direct depth transformation and one-dimensional nonlinear regularization inversion algorithms of the magnetic component responses are proposed for geo-object interpretation. With the help of the empirical mode decomposition (EMD), an SLF data processing workflow is demonstrated theoretically and practically, which is integrated into a portable instrument. The instrument’s ability to identify the low-resistivity reservoirs and their surrounding rocks has been proved by field survey. The extraction of electromagnetic radiation (EMR) anomalies also helps to refine the reservoir interpretation with higher accuracy. A joint comparative inversion test between the SLF method and the audio-magnetotelluric method (AMT) is also addressed, demonstrating that the SLF method is reliably applicable in the field survey of CBM reservoirs. A preliminary statistical analysis shows that the depth resolution of CBM reservoirs can reach the order of tens of meters. Therefore, the SLF method is expected to become one of the most potential options for in-situ CBM exploration with a cost-effective interpretation capability.
      Citation: Minerals
      PubDate: 2022-05-28
      DOI: 10.3390/min12060680
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 681: Multicomponent Transient Electromagnetic
           Exploration Technology and Its Application

    • Authors: Xingchun Wang, Qingquan Zhi, Junjie Wu, Xiaohong Deng, Yue Huang, Qi’an Yang, Jinhai Wang
      First page: 681
      Abstract: To take full advantage of the multicomponent transient electromagnetic method, we summarize the advantages of multicomponent exploration based on simulation calculation. We have carried out experiments on the effectiveness of the method in the known copper-nickel mining area. The results show that the characteristic curve of the horizontal component can effectively point to the central direction of the low-resistivity ore body and reflect the occurrence of the ore body. The degree of coupling between the vertical component and the ore body is high, which is beneficial for quantitative inversion. The results for the horizontal component and vertical component interpretations are consistent, which reduces the limitation of conventional single vertical component interpretation and effectively improves the work efficiency in field work.
      Citation: Minerals
      PubDate: 2022-05-28
      DOI: 10.3390/min12060681
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 682: Denoising Marine Controlled Source
           Electromagnetic Data Based on Dictionary Learning

    • Authors: Pengfei Zhang, Xinpeng Pan, Jiawei Liu
      First page: 682
      Abstract: Marine controlled source electromagnetic (CSEM) is an efficient method to explore ocean resources. The amplitudes of marine CSEM signals decay rapidly with the measuring offsets. The signal is easily contaminated by various kinds of noise when the offset is large. These noise include instrument internal noise, dipole vibration noise, seawater motion noise and environmental noise Suppressing noise is the key to improve data quality and interpretation accuracy. Sparse representation based denoising method has been used for denoising for a long time. provides a new way to remove noise. Under the framework of sparse representation, the denoising effect is closely related to the chosen transform matrix. This matrix is called dictionary and its column named atom. In general, the stronger the correlation between signal and dictionary is, the sparser representation will be, and further the better the denoising effect will be. In this article, a new method based on dictionary learning is proposed for marine CSEM denoising. Firstly, the signal segments suffering little from noise are captured to compose the training set. Then the learned dictionary is trained from the training set via K-singular value decomposition (K-SVD) algorithm. Finally, the learned dictionary is used to sparsely represent the contaminated signal and reconstruct the filtered one. The effectiveness of the proposed approach is verified by a synthetic data denoising experiment, in which windowed-Fourier-transform (WFT) and wavelet-transform (WT) denoising methods and three dictionaries (discrete-sine-transform (DST) dictionary, DST-wavelet merged dictionary and the learned dictionary) under a sparse representation framework are tested. The results demonstrate the superiority of the proposed dictionary-learning-based denoising method. Finally, the proposed approach is applied to field data denoising process, coupled with DST and DST-wavelet dictionaries based denoising methods. The outcomes further proves that the propsoed approach is effective and superior for marine CSEM data denoising.
      Citation: Minerals
      PubDate: 2022-05-28
      DOI: 10.3390/min12060682
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 683: Effect of Blunging/Dispersion Parameters on
           Separation of Halloysite Nanotubes from Gangue Minerals

    • Authors: Emrah Durgut, Mustafa Cinar, Mert Terzi, Ilgin Kursun Unver, Yildiz Yildirim, Feridun Boylu, Orhan Ozdemir
      First page: 683
      Abstract: Clay minerals need to be dispersed with blungers before their utilization in the related industries due to their plastic properties, and size reduction is carried out in a wet medium. Clay minerals also contain impurities such as nonplastic materials in their structure. Mechanical dispersion parameters are important in the separation of clay group minerals (halloysite and kaolinite) from their typical non-clayey gangue minerals (quartz and goethite). In this study, the removal of impurities from halloysite ore obtained from Kızıldam, Turkey, was examined in terms of mechanical dispersion parameters, namely, feed size, blunging time and speed, pulp concentration, pulp temperature, and the aging process. The effect of these parameters on halloysite dispersion was determined by particle size, chemical, and mineralogical analysis, and optical and scanning electron microscope images. The results obtained from the studies of the mechanical dispersing and particle size distribution of the products indicated that the optimum dispersion parameters were determined as −10 mm feed size, 8 h, and 1000 rpm blunging time, and speed, 35% pulp concentration at 25 °C pulp temperature. Under these optimum conditions, a 72.3% amount of −38 μm clay product containing 35.6% of halloysite, 46.5% of kaolinite, 12.0% quartz, 1.9% goethite, 0.9% gibbsite, and 3.2% other minerals were obtained from the halloysite ore, having 30.5% of halloysite, 43.4% of kaolinite, 19.1% quartz, 2.9% goethite, 1.4% gibbsite, and 2.7% other minerals. In this study, it was understood that feed size, pulp concentration, blunging time, and speed were important parameters, while pulp temperature and the aging process had no significant effect on the mechanical dispersion of Kızıldam halloysite. In addition, impurities such as quartz and iron-bearing minerals were separated from the ore by blunging and sieving.
      Citation: Minerals
      PubDate: 2022-05-28
      DOI: 10.3390/min12060683
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 684: Improving Inversion Quality of IP-Affected
           TEM Data Using Dual Source

    • Authors: Qingquan Zhi, Junjie Wu, Xiu Li, Xingchun Wang, Xiaohong Deng
      First page: 684
      Abstract: The induced polarization (IP) effects in transient electromagnetic (TEM) responses pose difficulties to the TEM data interpretation and inversion. The IP effects break the monotony in TEM decay curves and can even cause sign reversals and lead to the singularity and non-monotony of inversion. The singularity problem is still urgent to be solved. In this paper, the forward modeling method of IP-affected TEM responses is developed using the Cole–Cole model and a frequency-time domain transformation. A TEM data acquisition scheme using a dual-source method without a significant increase in field work is proposed to weaken the singularity and improve the inversion quality finally. Based on the modeling and analysis, the dual-source scheme is designed to guarantee all stations be measured twice with different loops. The joint inversion of dual-source datasets is realized by using an objective combing function and the particle swarm optimization (PSO) algorithm. The synthetic data test proved the validity of the algorithm and illustrated that the joint dual-source method greatly weakened the singularity and stabilized the inversion. The field example of the Baiyun golden deposit showed well consistency with resistivity logging and TEM logging results and predicted the gold mineralization below 2000 m.
      Citation: Minerals
      PubDate: 2022-05-28
      DOI: 10.3390/min12060684
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 685: Total vs. Partial Acid Digestion Methods for
           Trace Element Analysis in Archaeological Sediments

    • Authors: Gianni Gallello, Mirco Ramacciotti, Oreto García Puchol, Marco Lezzerini, Sarah B. McClure, Agustín Pastor
      First page: 685
      Abstract: Trace element analysis of sediments from archaeological sites is a valuable method to investigate the anthropic impact and obtain information on the functions of different areas and changes in human activities. One of the most used and effective techniques to carry out this kind of analysis is inductively coupled plasma–mass spectrometry. This technique needs a previous dissolution of the sample by acid attack, but the development of the best method is still a discussed issue. In the present work, total and partial digestion methods were carried out in sediment samples of Cueva de la Cocina (Dos Aguas, Spain), and trace elements were measured and statistically compared. Major elements, soil organic matter amount, and pH data were used to evaluate the main drivers of trace element contents. The differences between the results from the two methods were highlighted. Total digestion is more effective for aluminosilicates and heavy minerals, although the partial digestion results suggested that, in most cases, the difference between the two methods is irrelevant for archaeological interpretations. Furthermore, in some cases, the total digestion of the mineral phases related to the geological contribution could mask the anthropic elemental signals.
      Citation: Minerals
      PubDate: 2022-05-29
      DOI: 10.3390/min12060685
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 686: Editorial for Special Issue “Deep-Sea
           Ferromanganese Nodules and Related Mineral Resources: Genesis,
           Exploration, and Mining”

    • Authors: Shiki Machida, Kentaro Nakamura
      First page: 686
      Abstract: The development of deep-sea ferromanganese nodules has the potential to provide critical metals for the creation of high-tech and green-tech technologies and devices [...]
      Citation: Minerals
      PubDate: 2022-05-29
      DOI: 10.3390/min12060686
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 687: Comparison of the Effects of Sodium Oleate
           and Benzohydroxamic Acid on Fine Scheelite and Cassiterite Hydrophobic

    • Authors: Saizhen Jin, Leming Ou
      First page: 687
      Abstract: Sodium oleate (NaOL) and benzohydroxamic acid (BHA) are commonly used scheelite and cassiterite flotation collectors. Hydrophobic flocculation flotation of fine minerals has been extensively studied and reported under a NaOL system, but not under a BHA system. In this paper, the particle size distribution and flotation behaviour of fine scheelite (−10 μm) and cassiterite (−37 + 10 and −23 μm) after shear stirring in NaOL, BHA, and Pb2+ + BHA systems were studied by laser particle size analysis and flotation tests. The measured particle size distribution results revealed that the fine minerals could aggregate under a NaOL system, and the aggregate size increased with increasing stirring time and speed, with scheelite aggregating faster than cassiterite. BHA did not cause scheelite or cassiterite to form hydrophobic aggregates. At low stirrer speeds, the minerals could form small, weak, and easily broken aggregates when Pb2+ + BHA was added. The results of the flotation tests revealed that increasing the stirring time and speed increased the flotation rate and recovery when NaOL and BHA were added. When Pb2+ + BHA was added, however, the changes in flotation rate and recovery were not noticeable when the stirring conditions were changed.
      Citation: Minerals
      PubDate: 2022-05-29
      DOI: 10.3390/min12060687
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 688: Composition and Geochemical Characteristics
           of Pyrite and Quartz: Constraints on the Origin of the Xinjiazui Gold
           Deposit, Northwestern Margin of the Yangtze Block, China

    • Authors: Ji Liu, Xinshang Bao, Yongbao Gao, Ke Yang, Shaolei Kou, Wei Yang, Zhanbin Wang, Jinglong He, Yixiang Zhang, Hao Chen
      First page: 688
      Abstract: The Xinjiazui gold deposit, a newly discovered deposit, is situated in the northwestern margin of the Yangtze Block, China. The source and genesis of gold mineralization are poorly understood. It is urgent to use the H–O isotopic composition of quartz and geochemistry of pyrite to evaluate the origins of the Au and ore-forming fluids of this deposit. Three types of pyrite were identified, including synsedimentary framboidal pyrites (Py0), the directional arrangement of pyrites in pre-mineralization stage (Py1), and euhedral coarse-grain pyrites in the quartz–sulfide veins of the mineralization stage (Py2). The As content in Py2 is relatively higher than Py0 and Py1, indicating that the ore-forming fluids are strongly enriched in As. The δ34S values of Py2 (+5.50–+13.34‰) overlap with the S1–2M phyllite (+7.25‰–+8.70‰). This result is consistent with the Pb isotopic composition of Py2, showing that the source of ore-forming materials was derived from the S1–2M phyllite. Meanwhile, the variations in quartz’s H and O isotopic composition suggest that the ore-forming fluids were derived originally from metamorphic fluid. Additionally, the Au mineralization is strictly controlled by the shear zone. Above all, we would like to classify the Xinjiazui deposit as an orogenic gold deposit.
      Citation: Minerals
      PubDate: 2022-05-29
      DOI: 10.3390/min12060688
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 689: Combination of Machine Learning Algorithms
           with Concentration-Area Fractal Method for Soil Geochemical Anomaly
           Detection in Sediment-Hosted Irankuh Pb-Zn Deposit, Central Iran

    • Authors: Sasan Farhadi, Peyman Afzal, Mina Boveiri Konari, Lili Daneshvar Saein, Behnam Sadeghi
      First page: 689
      Abstract: Prediction of geochemical concentration values is essential in mineral exploration as it plays a principal role in the economic section. In this paper, four regression machine learning (ML) algorithms, such as K neighbor regressor (KNN), support vector regressor (SVR), gradient boosting regressor (GBR), and random forest regressor (RFR), have been trained to build our proposed hybrid ML (HML) model. Three metric measurements, including the correlation coefficient, mean absolute error (MAE), and means squared error (MSE), have been selected for model prediction performance. The final prediction of Pb and Zn grades is achieved using the HML model as they outperformed other algorithms by inheriting the advantages of individual regression models. Although the introduced regression algorithms can solve problems as single, non-complex, and robust regression models, the hybrid techniques can be used for the ore grade estimation with better performance. The required data are gathered from in situ soil. The objective of the recent study is to use the ML model’s prediction to classify Pb and Zn anomalies by concentration-area fractal modeling in the study area. Based on this fractal model results, there are five geochemical populations for both cases. These elements' main anomalous regions were correlated with mining activities and core drilling data. The results indicate that our method is promising for predicting the ore elemental distribution.
      Citation: Minerals
      PubDate: 2022-05-29
      DOI: 10.3390/min12060689
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 690: The Origin of Synchysite-(Ce) and Sources of
           Rare Earth Elements in the Rožná Uranium Deposit, Czech

    • Authors: Bohdan Kříbek, Ilja Knésl, Petr Dobeš, František Veselovský, Přemysl Pořádek, Radek Škoda, Ranata Čopjaková, Jaromír Leichmann, Filip Košek
      First page: 690
      Abstract: Synchysite was identified in the Rožná uranium deposit in a quartz–carbonate–sulfide vein, which is a part of the late (post-uranium and, post-Variscan) stage of the development of the hydrothermal system. The synchysite forms needles or lamellae, which are almost exclusively bound to the quartz filling of the veins. The structure of the quartz vein-filling, i.e., the preserved tubular syneresis crack pattern, Liesegang bands formed by hematite, chaotic grain size distribution of quartz grains, and ribbons of fibrous SiO2 grains, indicate that the synchysite crystallized in a silica gel. Its formation may be explained by the reaction of hydrothermal acid fluids rich in Fe2+ and rare earth elements (REEs) with alkaline Ca2+ HCO3− and F-rich fluids expelled from the gel during syneresis, or by its ageing. The subsequent recrystallization of the gel to form euhedral quartz grains was accompanied by the deformation of previously formed Liesegang rings, and the development of quartz rosettes. The study of fluid inclusions indicated that the silica gel originated at a very low temperature. The temperatures of the homogenization of two-phase inclusions in carbonate and quartz vein-filling varied between 38 and 74 °C, and the salinity ranged between 4 and 10 wt.% NaCl equiv. The δ13C carbonate values (from −4.65 to −5.21‰, PDB) indicate the deep-seated source of CO2, and δ18O values (from 14.76 to 18.22‰, SMOW) show that the source of the hydrothermal fluids was mainly surface water, with a possible admixture of fossil saline brines. The main sources of REEs are thought to have predominantly been uranium minerals (coffinitized uraninite and coffinite) that form a part of the breccia fragments embedded in the vein filling. The results illustrate the significant mobility of REEs in the late, low-temperature hydrothermal system, and they indicate the multiple remobilizations of REEs in the uranium deposits in general.
      Citation: Minerals
      PubDate: 2022-05-29
      DOI: 10.3390/min12060690
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 691: Representative-Area Approach to Define
           Blast-Induced Ground Vibrations—Damage Prevention Criterion Abacus

    • Authors: Rafael Rodríguez, Marc Bascompta, Patricia Fernández, Pablo R. Fernández
      First page: 691
      Abstract: Ground vibrations due to blasting can cause damage to nearby structures. In this context, a damage prevention criterion was developed to avoid this potential risk, establishing a limit value for the Peak Particle Velocity (PPV) as a function of ground natural frequency and type of structure to protect. In addition, several empirical attenuation laws to estimate the PPV and frequency as a function of the distance and amount of explosive were also developed. These models can be used to separately predict PPV and frequency, obtaining the representative point of the designed blast and decide if a potential damage could exist or not. The proposed approach allows one to simultaneously work with an attenuation law for the PPV and another one for the frequency, defining an area in the damage criterion abacus instead of a single representative point. The system was applied using data from 75 blasts in different limestone quarries in the north of Spain.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060691
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 692: Identification of Radioactive Mineralized
           Lithology and Mineral Prospectivity Mapping Based on Remote Sensing in
           High-Latitude Regions: A Case Study on the Narsaq Region of Greenland

    • Authors: Li He, Pengyi Lyu, Zhengwei He, Jiayun Zhou, Bo Hui, Yakang Ye, Huilin Hu, Yanxi Zeng, Li Xu
      First page: 692
      Abstract: The harsh environment of high-latitude areas with large amounts of snow and ice cover makes it difficult to carry out full geological field surveys. Uranium resources are abundant within the Ilimaussaq Complex in the Narsaq region of Greenland, where the uranium ore body is strictly controlled by the Lujavrite formation, which is the main ore-bearing rock in the complex rock mass. Further, large aggregations of radioactive minerals appear as thermal anomalies on remote sensing thermal infrared imagery, which is indicative of deposits of highly radioactive elements. Using a weight-of-evidence analysis method that combines machine-learned lithological classification information with information on surface temperature thermal anomalies, the prediction of radioactive element-bearing deposits at high latitudes was carried out. Through the use of Worldview-2 (WV-2) remote sensing images, support vector machine algorithms based on texture features and topographic features were used to identify Lujavrite. In addition, the distribution of thermal anomalies associated with radioactive elements was inverted using Landsat 8 TIRS thermal infrared data. From the results, it was found that the overall accuracy of the SVM algorithm-based lithology mapping was 89.57%. The surface temperature thermal anomaly had a Spearman correlation coefficient of 0.63 with the total airborne measured uranium gamma radiation. The lithological classification information was integrated with surface temperature thermal anomalies and other multi-source remote sensing mineralization elements to calculate mineralization-favorable areas through a weight-of-evidence model, with high-value mineralization probability areas being spatially consistent with known mineralization areas. In conclusion, a multifaceted remote sensing information finding method, focusing on surface temperature thermal anomalies in high-latitude areas, provides guidance and has reference value for the exploration of potential mineralization areas for deposits containing radioactive elements.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060692
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 693: Geochemical Characteristics of Chlorite in
           Xiangshan Uranium Ore Field, South China and Its Exploration Implication

    • Authors: Yongjian Wang, Honghai Fan, Yaqing Pang, Wei Xiao
      First page: 693
      Abstract: Chlorite is one of the most important hydrothermal minerals in many hydrothermal uranium deposits worldwide and is commonly closely associated with the uranium mineralization. Trace elements in chlorite have been extensively applied to fingerprinting the hydrothermal fluid evolution and indicating the concealed ore bodies in porphyry Cu (-Au) deposits and skarn-related Pb-Zn deposits. However, this approach was rarely attempted on hydrothermal uranium deposits to date. Xiangshan uranium ore field, located in the southeast part of Gan-Hang Metallogenic (or Volcanic) Belt (GHMB), is the largest volcanic-related ore field in the whole country. In this study, the focus was placed on the petrographic characteristics and trace elements in hydrothermal chlorite from two typical deposits (Zoujiashan and Yunji) at Xiangshan. Four types of chlorites were identified, i.e., Chl1-Y and Chl2 from Yunji deposit, and Chl1-Z and Chl3 from Zoujiashan deposit. The pre-ore Chl1-Y and Chl1-Z are formed through replacing the original magmatic biotite. Chl2 and Chl3 occur as veinlets or disseminated, and are closely associated with early-ore U mineralization and main-ore U mineralization, respectively. All the four types of chlorites are typically trioctahedral chlorite. Vein-type/disseminated Chl2 and Chl3 in ore veins were precipitated directly from the hydrothermal fluids through dissolution-migration-precipitation mechanism, whereas the replacement-type chlorite was formed by the dissolution–crystallization mechanism. Empirical geothermometry indicates that the chlorite from Yunji and Zoujiashan were crystallized at 179~277 °C, indicating a mesothermal-epithermal precipitation environment. EPMA and LA-ICP-MS results show that the replacement-type chlorite has relatively consistent compositions at Yunji and Zoujiashan. Both Chl2 and Chl3 are enriched in U, Th but depleted in Mn and Ti. Compared with the Chl2 related to early-ore U mineralization, Chl3 that formed at main-ore stage has higher concentrations of Fe, U, Th, REEs, Mn and Ti, as well as higer Fe/(Fe + Mg) ratios. Such compositional differences between Chl2 and Chl3 are mainly attributed to the formation temperatures and fluid compositions/natures. Combined with petrology and chemical compositions of different types of chlorite, we propose that the presence of vein-type/disseminated chlorite with high U and Fe/(Fe + Mg) ratio but relatively low Mn, Ti and Pb contents can be regarded as an effective vector toward the most economic (high U grade) mineralized zone, whereas the occurrence of Chl2 is likely to indicate the subeconomic U mineralization and less potential exploration for uranium at depth.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060693
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 694: Mineralogical Criteria for the Prediction of
           Gold Mineralization in the Structures of the Siberian Craton

    • Authors: Zinaida Nikiforova
      First page: 694
      Abstract: Generalization of the results of the study of placer gold and the mechanisms of its distribution in the east of the Siberian Platform made it possible for the first time to reveal that the ore sources of gold-bearing placers were mainly mineralization of the gold-sulfide formation formed under the influence of hydrothermal metasomatic processes occurred in deep fault zones. It is determined that the gold-bearing hydrothermal-metasomatic formations of the gold-sulfide rock formation are amagmatic, near-surface, low-temperature and spatially confined to deep faults. These formations are widespread in terrigenous-carbonate strata and sand deposits of PZ-MZ age and are observed in the zones of brecciation, silicification, and ferruginization. The analysis of the mechanisms of distribution of hydrothermal-metasomatic gold-bearing formations in the east of the Siberian Platform, based on previously conducted research of predecessors and our field observations, allowed us to establish the following. In the northeast, hydrothermal-metasomatic formations occur in the field of development of the Zhigansky fault, the Molodo-Popigai and Anabar-Eekite fault system, in the central part of the east of the Siberian Platform, the Vilyui paleorift (Kempendyai dislocations), and in the southeast in the Baikal-Patom thrust belt in ancient faults (Bappagai, Khorinsky, etc.). Metasomatites of hydrothermal origin form extended narrow formations along ancient faults activated in the Mesozoic, as well as conformable deposits in the Vendian, Cambrian carbonate strata, Jurassic and Cretaceous sandstones. It is proved that these formations are amagmatic and are not related to the widespread magmatism of the basic composition, which is confirmed by the homogenous mineral composition of metasomatites, independent of the composition of magmatic bodies spatially located with them. Zones of metasomatites with gold mineralization contain Au from 0.5 to 3.0 g/t, and in isolated cases up to 24–32 g/t. Gold is represented from finely-dispersed to visible fine, with a size from 0.01 to 0.5 mm or more. It is known that hydrothermal-metasomatic processes on the territory of Central Aldan contributed to the formation of large deposits such as Kuranakh, Tabornoye and others. It is possible that the identified gold-ore metasomatites, developed along the zones of regional faults and not confined to magmatic formations, widely occurred both in the northeast and in the southeast of the Siberian Platform, represent a huge metallogenic potential.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060694
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 695: Ore Processing Technologies Applied to
           Industrial Waste Decontamination: A Case Study

    • Authors: Hernan Anticoi, Josep Oliva Moncunill, Carlos Hoffman Sampaio, Rubén Pérez-Álvarez, Beatriz Malagón-Picón
      First page: 695
      Abstract: The correct management of industrial waste, as well as being an environmental obligation, can also be used as an opportunity to reduce costs in terms of energy and raw material consumption. A large amount of waste sand is generated in foundries with a high content of pollutants adhering to its surface structure. In this study, the material utilized consists of a silicic sand that comes from a casting process, with a thin layer of fixed carbon on the surface of the particles. The objective is to remove this contaminant, in order to have clean sands for use in alternative processes, such as in glass raw material, green concrete, or in the recirculation of these in the same process. The mechanical action that is best for eliminating surface attached contaminants is abrasion. In this regard, two specific devices, commonly used in ore processing operations, were utilized to apply energy in a material in order to reach abrasion by attrition, but with different kinetic approaches: stirring in a slurry media and using a light milling, in both cases reducing the grinding media in order to avoid material fracture. The test performance evaluation is mainly focused on the decontamination efficiency, the sand mass recovery ratio, and the energy consumption. The results show that in all cases, liberation is reachable in different levels at different residence times. We were able to decrease the LOI content from 4% to less than 1%, combined with a near 85% recovery rate of clean sand in the case of stirring. In the case of light milling, the results are even better: the final product reached near 0.5% of LOI content, despite mass flow recovery potentially being less than 80%. Finally, we discuss whether energy consumption is the factor which decides the best alternative. The energy consumed ratio when comparing light milling with stirring is near 9:1, which is a significant amount when taking into account the importance of reducing energy consumption in today’s industry due to its economic and environmental impact.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060695
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 696: Sediment Characteristics—A Key Factor
           for Fish Farm Site Selection: Examples from Croatia

    • Authors: Kristina Pikelj, Anita Uroš, Anamarija Kolda, Ana Gavrilović, Damir Kapetanović
      First page: 696
      Abstract: The rapid development and intensive production of aquaculture have brought to light various environmental problems. In particular, fish farming adversely affects the benthic environments through the accumulation of organic matter (OM), which leads to the degradation of aquatic sediments and associated biotic communities. To prevent environmental degradation, proper site selection for fish farming is a prerequisite for sustainable aquaculture practices. An important physical factor in selecting a site for fish farming is sediment structure. Coarser sediments are preferred, while their mineral composition is rarely discussed. To investigate relationships between sediment characteristics and the content of OM, sediments were collected from three different sites with different aquaculture practices under different climatic and environmental conditions and analyzed during the one-year monitoring period. Grain size distribution, mineral composition, carbonate content, and organic matter content were determined for three fish farm sites (Ilova, River, Krka River, and Pelješac) and their reference sites. Preliminary results from all studied sites showed that sediment texture in combination with natural mineral composition is one of the key factors for the accumulation of OM in the sediment. In particular, the mineral composition of the fine-grained sediment should be known when conducting an environmental impact assessment of fish farms.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060696
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 697: Geochemical Characteristics of Tailings from
           Typical Metal Mining Areas in Tibet Autonomous Region

    • Authors: Rengui Weng, Guohong Chen, Xin Huang, Feng Tian, Liufang Ni, Lei Peng, Dongqi Liao, Beidou Xi
      First page: 697
      Abstract: With the exploring and developing of mineral resources in the Tibet Autonomous Region for many years, a large number of tailings have been produced. A total of 17 tailings samples from borehole cores were collected from different tailings ponds in different regions of Tibet. The results showed that the mineral composition and content of tailings in each research area were different. Among them, quartz was the most abundant mineral in most tailings. The major elements of tailings mainly included Si, Al, Fe, Mg, Mn, Ca, Na, K and so on. S existed in different types of tailings. In the analysis of trace element composition, it was found that the content of some elements had approached the lowest industrial grade, which has potential recycling value, such as Mn, Zn, Pb and P. Through the detection of radioactive elements (Ra-226, Th-232 and K-40), it was shown that there were great differences among different types of tailings, and their different contents would bring potential hazards to the safety of the surrounding environment and human health. Similar results were found in the analysis of particle size characteristics of tailings. These results are of great significance for the future utilization and resource utilization of tailings pond.
      Citation: Minerals
      PubDate: 2022-05-30
      DOI: 10.3390/min12060697
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 698: Effect of the Particle Size Composition and
           Dry Density on the Water Retention Characteristics of Remolded Loess

    • Authors: Xin-Qing Wang, Xiao-Chao Zhang, Xiang-Jun Pei, Guo-Feng Ren
      First page: 698
      Abstract: The experimental study on the water-holding characteristics of remolded loess was carried out, revealing the variation of water-holding characteristics with particle size composition and dry density. The results show that the air-entry value is positively correlated with the silt-sized content and negatively correlated with the sand-sized content. During the dehumidification of the specimens at a fixed dry density, when the air-entry value is between 9 and 10 Kpa, it is strongly influenced by the silt-sized content; however, beyond 10 Kpa, the sand-sized content is an important influencing factor. Changes in particle size composition have less influence on the residual water content. There is a non-linear relationship between the particle size composition and the slope λ of the dehumidification curve in the transition zone. Air-entry values, residual water content, saturated volumetric water content, and λ correlate well with dry density. Simulation tests were carried out using two power function models, including three variables. It was found that the VG model is a better fit than the Gardner model.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060698
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 699: Integration of Stress–Strain Maps in
           Mineral Systems Targeting for IOCG Mineralisation within the Mt. Woods
           Inlier, Gawler Craton, South Australia

    • Authors: Jonathan Nicholas Gloyn-Jones, Ian James Basson, Ben Stoch, Corné Koegelenberg, Michael-John McCall
      First page: 699
      Abstract: The application of finite element analysis is used to simulate the relative distribution and magnitude of stress–strain conditions during a geologically brief, NNW-SSE-oriented, extensional event (1595 Ma to 1590 Ma), co-incident with IOCG-hydrothermal fluid flow and mineralisation across the Mt Woods Inlier, Gawler Craton, South Australia. Differential stress and shear strain maps across the modelled terrane highlight regions that were predisposed to strain localization, extensional failure and fluid throughput during the simulated mineralisation event. These maps are integrated with other datasets and interpretation layers, one of which is a proposed structural–geometrical relationship apparent in many world-class IOCG deposits, including Prominent Hill, Olympic Dam, Sossego, Salobo, Cristalino and Candelaria. These deposits occur at steeply plunging, pipe-like intersections of conjugate extensional systems of faults, shears and/or contacts, wherein the obtuse angle may have been bisected by the maximum principal extensional axis (viz., σ3) during mineralisation. Several other layers are also used for the generation of targets, such as distance from major shear zones, favourable host lithologies, and proximity to tectonostratigraphic contacts of markedly contrasting competency. The result is an integrated target index or heat map for IOCG prospectively across the Mt. Woods Inlier.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060699
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 700: Process Mineralogy of Micro/Nano
           Silicon-Carbon Ore Obtained from Jiangxi, China

    • Authors: Shaowen Tang, Huan Shuai, Runtao Zhao, Gaoxiang Du, Xianguang Wang, Jiao Wang
      First page: 700
      Abstract: This study details the investigation of a black powder potential ore that was first obtained from Jiangxi, China. Its species, composition, and morphology are unknown. Preliminary tests revealed that the silica (SiO2) content of this ore is >70%. To test this ore more comprehensively, its mineralogical parameters (such as mineral composition, ore particle size, and mineral morphology) are investigated using X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), differential scanning calorimetry–thermogravimetry (DSC-TG), Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), laser particle size analysis, and elemental analysis (EA). Based on these analyses, it is determined that it is micro/nano silicon-carbon ore, and its genesis and species are discussed herein. The gangue minerals, such as α-quartz, kaolinite, pyrite, and muscovite, are finely disseminated and encapsulated by fixed carbon. The ore has an uneven morphology, with many holes and depressions. Moreover, nano-sized needle-like quartz and quartz wrapped by carbon are found on the surface of the ore. According to our results, this ore may have been formed by the long-term accumulation and consolidation of phytoliths. These results provide a technical reference for the development and utilization of the identified micro/nano silicon-carbon ore.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060700
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 701: Extraction of REEs from Blast Furnace Slag
           by Gluconobacter oxydans

    • Authors: Abhilash, Sabrina Hedrich, Pratima Meshram, Axel Schippers, Ajay Gupta, Subhadra Sen
      First page: 701
      Abstract: Granulated blast furnace slag (GGBFS) is a potential resource of rare earth elements (REEs), and due to the complex mineralogy, extraction by conventional hydrometallurgical process makes it an acid-consuming method. Bioleaching is thus investigated using a chemo-organotrophic bacterium Gluconobacter oxydans (DSMZ 46616) for REE extraction from GGBFS containing 157 ppm Ce, 90 ppm La, 71 ppm Nd and 40 ppm Er, hosted in a Ca-Al-Si matrix. The gluconic acid generation by G. oxydans was assessed for its role in REE extraction from GGBFS. With 5% (w/v) GGBFS using a mixture of a non-adapted and a GGBFS-adapted culture, a maximum solubilization of 67% and 88% Nd was observed after 12 and 40 days of incubation, respectively. The total amount of gluconic acid excreted by the bacteria increased with leaching duration, which contributed to a rise in metal extraction. Scanning electron microscope-energy dispersive analysis (SEM-EDAX) analysis of the solid residue showed bacterial cells in corrosion pits, and thereby assisting in metal solubilization.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060701
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 702: Field Experiments of Phyto-Stabilization,
           Biochar-Stabilization, and Their Coupled Stabilization of Soil Heavy Metal
           Contamination around a Copper Mine Tailing Site, Inner Mongolia

    • Authors: Hong Liu, Yanguo Teng, Nengzhan Zheng, Linmei Liu, Weifeng Yue, Yuanzheng Zhai, Jie Yang
      First page: 702
      Abstract: A field trial was conducted in Inner Mongolia to evaluate the stabilization effects of phyto-stabilization, biochar-stabilization, and their coupled stabilization for As, Cu, Pb, and Zn in soil. Stabilization plants (Achnatherum splendens, Puccinellia chinampoensis, and Chinese small iris) and biochar (wood charcoals and chelator-modified biochar) were introduced in the field trial. The acid-extractable fraction and residual fraction of the elements were extracted following a three-stage modified procedure to assess the stabilization effect. The results after 60 days showed that the coupled stabilization produced a better stabilization effect than biochar-/phyto- stabilization alone. Achnatherum splendens and Puccinellia chinampoensis were found to activate the target elements: the residual fraction proportion of As, Cu, Pb, and Zn decreased while the acid-extractable fraction proportion of Cu and Zn increased in the corresponding planting area. Neither type of biochar produced a notable stabilization effect. The residual fraction proportion of As (20.8–84.0%, 29.2–82%), Pb (31.6–39.3%, 32.1–48.9%), and Zn (30.0–36.2%, 30.1–41.4%) increased, while the acid-extractable fraction proportion remained nearly unchanged after treatment using Chinese small iris-straw biochar or Achnatherum splendens-straw biochar, respectively. The results indicate that phyto-stabilization or biochar-stabilization alone are not suitable, whereas the coupled stabilization approach is a more efficient choice.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060702
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 703: Characterization and Leaching Kinetics of
           Rare Earth Elements from Phosphogypsum in Hydrochloric Acid

    • Authors: Qingjun Guan, Ying Sui, Chufeng Liu, Yongjie Wang, Chuxiong Zeng, Weijian Yu, Zhiyong Gao, Zhenyue Zang, Ru-an Chi
      First page: 703
      Abstract: The characterization and leaching mechanism of REEs from phosphogypsum (PG) in HCl was studied in-depth. REEs contained in the PG were 208 ppm, of which Y, La, Ce, and Nd were the four most abundant elements. The modes of occurrence of rare earth elements (REEs) in the PG were quantified using the sequential chemical extraction (SCE) method. Among the five REE occurrence species, the metal oxide form accounted for the largest proportion, followed by the residual, organic matter, and ion-exchangeable fractions, and REEs bound to carbonates were the least. From the comparison of the distributions of REEs and calcium in different occurrence states, it can be determined that REEs contained in the PG were mainly present in the residue state (existed in the gypsum lattice) and the metal oxide state (easily leached). The leaching results show that the suitable leaching conditions were acid concentration of 1.65 mol/L, S/L ratio of 1/10, and reaction temperature of 60 °C. At the condition, the maximum leaching efficiency for ∑REE was 65.6%, of which the yttrium leaching rate was the highest and reached 73.8%. Importantly, A new kinetic equation based on the cylindrical shrinking core model (SCM) was deduced and could well describe REE leaching process from PG. The apparent activation energy for ∑REE leaching was determined to be 20.65 kJ·mol−1.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060703
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 704: Mechanical Properties and Acoustic Emission
           Characteristics of Water-Bearing Coal Specimens under a Coupled
           Compression–Shear Load

    • Authors: Lan Wang, Peng Wu, Ming Li, Xianbiao Mao, Liang Chen
      First page: 704
      Abstract: The construction of an underground coal mine reservoir plays an essential role in the ecological environment of arid areas. The moisture content and loading angle inclination significantly impact the strength and stability of the safety coal pillar of underground reservoirs. Water-bearing coal was investigated under a coupled compression–shear load using inclined uniaxial compression tests on coal samples with varying water contents (ω = 0%, 2.42%, 5.53%, 7.55%, and 10.08%) and acoustic emission (AE) technology. The weakening mechanism of the mechanical property parameters and the crack evolution law, combined with the characteristics of the stress–strain curve, the cumulative AE count, and the cumulative AE energy methods, were used. Therefore, the evolution law of the coal’s crack closure (CC) threshold, crack initiation (CI) threshold, and crack damage (CD) threshold was analyzed. The results indicate that coal samples’ peak stress and elastic modulus decreased when the water content or inclination angle increased. Peak shear stress decreased as the water content rose, and the overall characteristics gradually rose as the inclination angle increased. The exception was when the ratio was 10.08%; when the inclination angle was 0°, the failure mode of the coal sample progressively changed from tension failure (ω = 0%, 2.42%) to tension–shear composite failure (ω = 5.53%), and finally to shear failure (ω = 7.55%, 10.08%). When the inclination angle was 5°, the coal sample was dominated by tension–shear composite failure at any moisture content. When the inclination angle was 10° and 15°, the coal specimens showed shear failure at any moisture content. The evolution law of tensile and shear cracks determined by AE characteristic parameters was consistent with the macrofracture characteristics of the coal specimens. When the water content or inclination angle increased, the crack closure threshold, crack initiation threshold, and damage threshold of the coal samples decreased. Therefore, these results show that their peak stress ratio does not depend on the water content or inclination angle.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060704
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 705: Effect of Unhydrated Aminopropyl
           Triethoxysilane Modification on the Properties of Calcined Kaolin

    • Authors: Jincai Zhang, Peng Zhang, Fangqin Cheng
      First page: 705
      Abstract: Unhydrated aminopropyl triethoxysilane was used to modify calcined kaolin produced from coal-bearing kaolinite. The aim was to develop a simple and economic modification method without the need for solution immersion and subsequent wastewater treatment. The samples before and after modification were tested using multiple methods, such as XRD, MAS-NMR, FT-IR, XPS, and SEM. The study results indicate that this modification can effectively improve the surface property of calcined kaolin. The activity index increased to 76.7% when the modifier usage was 2%. With a further increase in the modifier content, the activity index decreased. Surface modification did not reduce the whiteness of calcined kaolin. Further, the modification reaction mechanism was elucidated. Based on the detailed analyses, it was found that the modification reaction took place between the NH2 groups in the modifier molecules and AlVI-OH in calcined kaolin, and hydrogen bonds were formed between the NH2 groups and the active sites on the calcined kaolin surface.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060705
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 706: Geochronological and Geochemical Constraints
           on the Petrogenesis of Lamprophyre from the Giant Weishan REE Deposit in

    • Authors: Yi-Zhan Sun, Kun-Feng Qiu, Mao-Guo An, Shan-Shan Li, Zhen Shang, Yu Wang
      First page: 706
      Abstract: The Weishan REE deposit is located in the southwest of the Luxi Terrane of the North China Craton (NCC), where a large number of lamprophyre dikes are spatially exposed with the deposit. Here, we report petrology, geochemistry and zircon U-Pb geochronology data for the lamprophyre of the Weishan REE deposit in order to develop constraints for the determination of the petrogenesis, magma source and evolution of the lamprophyre and the tectonic environment. LA-LCP-MS zircon U-Pb dating shows that the crystallization age of the lamprophyre is 125 ± 0.86 Ma. The geochemical data suggest that these lamprophyres have high levels of Al2O3, K2O, MgO and alkalis, moderate level of Na2O and low levels of SiO2, Fe2O3 and TiO2, and that they are enriched with LREEs (La, Ce) and LILEs (Rb, Ba) and depleted with regard to HREEs and HFSEs (Nb, Ta, Ti). They displayed negative εHf(t) values of −14.98 to −9.03, TDM1 ages of 1.1–1.4 Ga and TDM2 ages of 1.7–2.1 Ga, which suggest that the magma source originates from an enriched mantle. Low Rb/Sr and high Dy/Yb ratios suggest that the enriched mantle source was partially melted at the amphibole-bearing lherzolite garnet-facies. The high Ba/Th and Sr/Th ratios indicate that the enriched source was derived from subduction dehydration fluids of the oceanic crust. We propose that the mafic dike intrusions are consistent with an Early Cretaceous alkaline magma emplacement in an extensional setting, in which the magma was not contaminated by crustal material during its emplacement.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060706
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 707: Geochronology and Geochemistry of the
           Granite Porphyry from the Qinglingou Gold Deposit, South Qinling, China:
           Implication for Petrogenesis and Mineralization

    • Authors: Kun Ding, Xiuqing Yang, Hui Wang, Ying Li, Kai Liu, Zhihui Wang, Liang Zhao, Yanjun Chen
      First page: 707
      Abstract: The Zhashui-Shanyang ore cluster area is one of the most important gold polymetallic ones in northwestern China. The Qinglingou gold deposit is a newly discovered small-scale deposit in the Zhashui-Shanyang area. Gold mineralization closely related to acid intrusive rocks has been found for the first time in this area. In this paper, the geochronology, whole-rock geochemistry, and isotope signature of the granite porphyries in the deposit are studied. They are characterized by variable medium SiO2 (67.22–71.72 wt.%), high K2O + Na2O contents (6.54–10.34 wt.%), and variable Al2O3 (14.47–15.10 wt.%) values. The A/CNK ratios range from 0.90 to 1.23, and the A/NK ratios vary from 1.14 to 1.48. These rocks also contain biotite and amphiboles and are similar to peraluminous and high-K calc-alkaline I-type granites. The Qinglingou granite porphyries show relative enrichment of Rb, Th, and K, and depletion of Nb, Ta, P, Ti, and other high field strength elements. These porphyries are enriched in light rare earth elements relative to heavy rare earth elements with weak negative Eu anomalies (δEu = 0.63–0.89), which is interpreted to be the best age of crystallization of the Qinglingou porphyries. LA–ICPMS zircon U–Pb dating yields an age of 211 ± 1.2 Ma (n=16, MSWD=0.39). The close spatial relationship between the ore bodies and granite porphyry dikes indicates that this age may represent the metallogenic age in this area. The zircons have 176Hf/177Hf ratios ranging from 0.282625 to 0.282702, the εHf(t) values are near 0 and the two-stage zircon Hf model ages range from 1121 to 1296 Ma. These data indicate that the Qinglingou granite porphyries were derived from the interplay between mantle- and crustal-derived magmas. We therefore propose that there is potential gold in carbonate rocks at the periphery of porphyry-skarn copper-molybdenum deposits.
      Citation: Minerals
      PubDate: 2022-05-31
      DOI: 10.3390/min12060707
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 708: Magma Sources and Tectonic Settings of
           Concealed Intrusive Rocks in the Jinchang Ore District,
           Yanbian–Dongning Region, Northeast China: Zircon U–Pb
           Geochronological, Geochemical, and Hf Isotopic Evidence

    • Authors: Zhigao Wang, Wenyan Cai, Shunda Li, Xuli Ma
      First page: 708
      Abstract: The Jinchang deposit is a large Au deposit in the Yanbian–Dongning region, in Northeast China, and is the product of magmatic–hydrothermal activities related to Early Cretaceous concealed igneous intrusions. However, these Early Cretaceous ore-causative igneous intrusions and the ore-hosting rocks in the Jinchang ore district have rarely been studied, with their magma sources and tectonic settings being ambiguous. Here, we integrate new geochemical, zircon U–Pb and Hf isotopic data from the concealed ore-hosting monzogranite and the ore-causative granodiorite to constrain their magma sources and tectonic settings. Zircon U–Pb dating indicates that the two monzogranites from the drill holes JIZKN01 and J18ZK0303 have similar crystallization ages of 202.0 ± 1.6 and 200.9 ± 1.2 Ma, respectively, whereas the granodiorite from the drill hole JXI-1ZK1001 was formed in the Early Cretaceous period (107.0 ± 3.0 Ma). They are all enriched in large-ion lithophile elements (e.g., Rb, Th, and K) and light rare-earth elements, depleted in high field strength elements (e.g., Nb, Ta, and Ti) and heavy rare-earth elements, and yield similar positive εHf(t) values of +4.4 to +11.5, with their two-stage model ages ranging from 799 to 389 Ma. These results indicate that the concealed Early Jurassic ore-hosting monzogranite was derived from the partial melting of the Neoproterozoic–Paleozoic continental crust in a continental arc setting related to the Paleo-Pacific subduction. The ore-causative granodiorite originated from the partial melting of both the mantle wedge and the overlying continental crust, most likely caused by the dehydration and metasomatism of the subducted Paleo-Pacific slab involved in the rollback in the Early Cretaceous period.
      Citation: Minerals
      PubDate: 2022-06-01
      DOI: 10.3390/min12060708
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 709: Optimization and Stability of the Bottom
           Structure Parameters of the Deep Sublevel Stope with Delayed Backfilling

    • Authors: Mochuan Guo, Yuye Tan, Da Chen, Weidong Song, Shuai Cao
      First page: 709
      Abstract: This study analyzes the stability and optimizes the parameters of the bottom structure in sublevel stoping with the delayed backfilling method, improves production efficiency, and increases the ore recovery ratio under the premise of ensuring safe production. Theoretical formulas are used to calculate the stability of the pillar with the bottom structure. Numerical simulation is used to study the stability of muck slash during excavation. Finally, the optimization parameters of the bottom structure are obtained by combining a similar physical experimental model and numerical simulation. The results show that the excavation of the muck slash caused different degrees of deformation at the roof and floor of the roadway. The largest stress occurred at the roadway crossing, whereas the smallest stress was in the middle area. The excavation also caused the secondary stress concentration at the adjacent bottom structure but did not significantly impact its stability. During the mining process, the largest displacement deformation occurred at the roadway crossing, and the influence of mining disturbance on the stability of the bottom structure involves timeliness and periodicity. Considering the recovery ratio, dilution ratio, and stability, the spacing of the extracted ore drift is recommended to be 9 m. This study ensures the stability of the bottom structure in the mining process and obtained reasonable parameters of the extracted ore drift, which provides a scientific way for the mines that use sublevel stoping with the delayed backfilling method.
      Citation: Minerals
      PubDate: 2022-06-01
      DOI: 10.3390/min12060709
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 710: Perspectives of Using DES-Based Systems for
           Solid–Liquid and Liquid–Liquid Extraction of Metals from

    • Authors: Rafael M. Dias, Mariana C. da Costa, Yecid P. Jimenez
      First page: 710
      Abstract: In recent years, the linear economic model and global warming have shown that it is necessary to move toward a circular economic model. In this scenario, the recycling of waste electrical and electronic equipment (WEEE) with green processes is one of the pending tasks; thus, in the present review, advances in the solid–liquid and liquid–liquid extraction processes, processes among the most important for the recovery of metals from ores or WEEE, with green solvents such as deep eutectic solvents (DES) are presented and analyzed, identifying the present and future challenges. To date, most articles focused on one of the processes, be it solid–liquid or liquid–liquid extraction, while few reports included the entire hydrometallurgical process, which could be due to heterogeneity of the WEEE, a characteristic that influences determining the leaching kinetic and the leaching mechanisms. A deeper understanding of the phenomenon would help improve this process and the next stage of liquid–liquid extraction. This also leads to the fact that, at the liquid–liquid extraction stage, most articles considered synthetic pregnant leach solutions to evaluate each of the variables, whereas the stripping of the ions and the recycling of the DESs in continuous processes is a challenge that should be addressed in future work. From the analysis, for WEEE leaching, it was identified that acid DESs are those achieving the best extraction percentages in the leaching of copper, lithium, and cobalt, among others, where the most studied hydrogen bond acceptor (HBA) is choline chloride with an acid (e.g., citric or lactic acid) as the hydrogen bond donor (HBD). For the liquid–liquid extraction of ions is a greater variety of HBAs (e.g., lidocaine, trioctylphosphine oxide and triphenyl phosphate) and HBDs (e.g., decanoic acid, thenoyltrifluoroacetone, and benzoyltrifluoroacetone) used; however, studies on the extraction of cobalt, lithium, copper, and nickel stand out, where the pH and temperature parameters have great influence.
      Citation: Minerals
      PubDate: 2022-06-02
      DOI: 10.3390/min12060710
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 711: Restoration Insights Gained from a Field
           Deployment of Dithionite and Acetate at a Uranium In Situ Recovery Mine

    • Authors: Paul Reimus, James Clay, Noah Jemison
      First page: 711
      Abstract: Mining uranium by in situ recovery (ISR) typically involves injecting an oxidant and a complexing agent to mobilize and extract uranium in a saturated ore zone. This strategy involves less infrastructure and invasive techniques than traditional mining, but ISR often results in persistently elevated concentrations of U and other contaminants of concern in groundwater after mining. These concentrations may remain elevated for an extended period without remediation. Here, we describe a field experiment at an ISR facility in which both a chemical reductant (sodium dithionite) and a biostimulant (sodium acetate) were sequentially introduced into a previously mined ore zone in an attempt to establish reducing geochemical conditions that, in principle, should decrease and stabilize aqueous U concentrations. While several lines of evidence indicated that reducing conditions were established, U concentrations did not decrease, and in fact increased after the amendment deployments. We discuss likely reasons for this behavior, and we also discuss how the results provide insights into improvements that could be made to the restoration process to benefit from the seemingly detrimental behavior.
      Citation: Minerals
      PubDate: 2022-06-02
      DOI: 10.3390/min12060711
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 712: The Ulug-Sair Gold Occurrence (Western Tuva,
           Russia): Mineralogy, Ore Genesis, and S-O Isotope Systematics

    • Authors: Renat V. Kuzhuget, Natalia N. Ankusheva, Franco Pirajno, Andrey A. Mongush, Yuri V. Butanaev, Nadezhda V. Suge-Maadyr
      First page: 712
      Abstract: Ulug-Sair Au-Bi-Te-Se mineralization is one prospect for native Au in the Western Tuva, and its origin remains debated. Mineralization consists of gold–sulfide–quartz veins in the host sedimentary rocks (conglomerates, siltstones, shales), quartz–tourmaline, and quartz–carbonate–sericite–altered rocks. To determine its origin, we examined the mineralogical–geochemical features, formation conditions, and fluid sources of the Ulug-Sair ore. A mineralogical–geochemical investigation outlines two substages with Au: an early gold–sulfide–quartz with pyrite, chalcopyrite, galena, gold, and electrum; and a late gold–telluride–sulfide–quartz, characterized by the presence of Bi-bearing minerals (AgBiTe, Bi2Te2Se, Cu3BiS3, Bi), tellurides (Au and Ag), Se-tellurides (Ag and Bi), and selenides (Au, Ag, and Hg). The paragenesis of Au–Ag tellurides, and fluid inclusion study data (microthermometry, Raman spectroscopy, LA-ICP-MS, and crush leach analysis (gas and ion chromatography, ICP-MS) in quartz showed that quartz–tourmaline-altered rocks were formed by an aqueous Mg–Na–K-chloride fluid with a salinity of 8–10 wt % NaCl eq. at 325–370 °C, whereas the host quartz–carbonate–sericite-altered rocks were formed from CO2–H2O fluid containing CH4 and N2, with a salinity of 0.18–6.1 wt % NaCl eq. at 200–400 °C. Gold-bearing mineral assemblages were formed at P ~ 0.75–1.0 kbar (~2.3–3 km) due to CO2–H2O chloride (Na–K ± Fe, Mg) fluid with CH4, Na2SO4, and Na2B2O5, and salinities 1.7–12.5 wt % NaCl eq. at temperatures decreasing from 360 up to 115 °C (gold–sulfide–quartz veins—360–130 °C, and gold–telluride–sulfide–quartz veins—330–115 °C), and variable fO2, fS2, fSe2, and fTe2. Results of the investigation of the isotope composition of S in pyrites indicates the magmatic origin of the fluid (δ18SH2S fluid from −0.4 to +2.5‰). The stable O isotope data in quartz indicates that, at an early substage, the formation of ore involved a fluid of magmatic and metamorphic origin (from +8.2 to +11.6‰), and, in the later substage, multiple sources of hydrothermal fluids (from +3.1 to +10.4‰), including magmatic-derived, metamorphic-derived, and meteoric waters. These data, in conjunction with structurally controlled mineralization, point towards similarities of the Ulug-Sair ore system with orogenic gold deposits.
      Citation: Minerals
      PubDate: 2022-06-02
      DOI: 10.3390/min12060712
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 713: A Methodology Combining IDEF0 and Weighted
           Risk Factor Analysis for the Strategic Planning of Mine Reclamation

    • Authors: Philip-Mark Spanidis, Christos Roumpos, Francis Pavloudakis
      First page: 713
      Abstract: The reclamation of lignite surface mines is a long-term commitment of high complexity. These reclamation projects consist of land use repurposing, reinstatement of landforms and landscape, remediation of polluted soils and water bodies, restoration of ecosystems, and other related activities, which are usually developed when mines enter the ultimate phase of their operational life. Nowadays, reclamation is supported by regulatory settings and legislative provisions, which motivate the affected communities to move towards a circular economy and sustainable development. This paper investigates the geoenvironmental and socioeconomic problems of reclamation and draws research questions on how the strategic planning of a reclamation project can be performed and how the relevant project risks can be investigated and managed. In turn, a prototype methodology based on experts’ judgment is suggested with a case study combining: (a) the IDEF0 (Integrated DEFinition Function) modelling technique, as a low cost and easy-to-develop tool enabling strategic planning of reclamation projects, and (b) the Weighted Risk Factor analysis as a suitable method for effective risk analysis and response planning in post-mining frameworks. Finally, a discussion on the methodology and proposals for further research are provided.
      Citation: Minerals
      PubDate: 2022-06-03
      DOI: 10.3390/min12060713
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 714: Experimental Setup for Evaluating Rock
           Volume Alteration and Its Application for Studying Shale Rock Swelling in
           Various Fluids

    • Authors: Timur I. Yunusov, Alexey V. Smirnov, Elena D. Mukhina, Dmitriy I. Potapenko, Dinar F. Bukharov, Anatoly A. Baluev, Alexey N. Cheremisin
      First page: 714
      Abstract: Rock swelling and rock disintegration in the presence of drilling, stimulation and completion fluids are considered to be the main reasons for operational and production problems for wells in clay-rich formations. The impact of these fluids on rock properties shall be established for the effective treatment design. This paper describes the development of the experimental setup for studying rock swelling in reservoir conditions and the application of this setup for the evaluation of swelling mechanisms of shale rock samples. Swelling quantification was performed using measuring piston displacement that was caused by rock swelling in a piston accumulator during pressure maintenance. We studied the interaction of the disintegrated rock samples with water-based and hydrocarbon-based fluids and supercritical CO2. It was found that alkaline water solution in reservoir conditions causes swelling of the used rock samples in the amount of 1–3% vol. with a direct correlation between the rock swelling magnitude and the total clay content. The change in the rock volume in the presence of the used hydrocarbon-based fluid depends on the content of organic matter, its distribution in the rock, and the clay content. The observed swelling degree in the hydrocarbon fluid and CO2 was significantly lower (0–0.5% vol.) than in water. The proposed methodology and obtained results can further be used for the optimization of various operations in clay-rich formations.
      Citation: Minerals
      PubDate: 2022-06-03
      DOI: 10.3390/min12060714
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 715: Long- and Short-Term Strategies for
           Estimation of Hydraulic Fracturing Cost Using Fuzzy Logic

    • Authors: Hyunjun Im, Hyongdoo Jang, Erkan Topal, Micah Nehring
      First page: 715
      Abstract: Over two decades, block caving mining has developed the application of hydraulic fracturing as a preconditioning method. This study aims to estimate hydraulic fracturing costs in block caving operations and suggests the base case of specified costs based on the U.S. Energy Information Administration (EIA) report. Furthermore, it applies cavability factors to develop the long- and short-term strategies through the fuzzy inference system. In the long-term strategy, we suggest three possible scenarios for reducing the long-term strategy’s uncertainty by considering the association for the advancement of cost engineering (AACE)’s contingency rate. Moreover, each fuzzy membership function of the three possible redeveloped scenarios was analysed through arithmetic operations over independent/dependent fuzzy numbers for comparing each scenario. The outcome of flexible cost estimation suggested deciding on the scale of infrastructure and ore production by facilitating undercut propagation and controlling block height of block caving operation including additional fragmentation processes. The result of this study also illustrated that systematic fuzzy cost engineering could help estimate the initial stage of budgeting. In addition, through solving the uncertainty of fuzzy calculation values, the project schedule identification is presented by recognising the dependence on each scenario’s common characteristic of the cavability parameter and cost contingency rate.
      Citation: Minerals
      PubDate: 2022-06-04
      DOI: 10.3390/min12060715
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 716: Mineralogical Fingerprint of Iron Ore
           Tailings in Paraopeba River Bedload Sediments after the B1 Dam Failure in
           Brumadinho, MG (Brazil)

    • Authors: Fernando Verassani Laureano, Rogerio Kwitko-Ribeiro, Lorena Guimarães, Lucas Pereira Leão
      First page: 716
      Abstract: The study presents SEM-based automated mineralogy to distinguish between natural sediments and iron ore tailings deposits from the Paraopeba River, after the failure of B1 Dam in Brumadinho, Minas Gerais, Brazil. Samples were obtained from borehole cores drilled over channel bars and banks eight months after the failure. After preliminary facies description, sediments from 54 chosen intervals were subjected to density measurement, X-ray diffraction (XRD), SEM-based automated mineralogy (QEMSCAN) analysis and determination of geochemical major components. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) revealed six main mineral associations governed by different contents and ratios of quartz, kaolinite and hematite. Natural sediments are predominantly composed of mineral associations containing kaolinite, quartz and quartz + hematite with density values ranging from 2.5 to 3.3 g/cm3. Tailings deposits have density values higher than 3.5 g/cm3 and are mainly composed of hematite with occasional occurrences of kaolinite + hematite. Because of geological complexity and historical terrain occupation and usage, geochemical anomalies are common in the Paraopeba River sediments. Our data suggests that mineralogical oriented studies should precede detailed geochemical investigations, to enhance the understanding of the source of such anomalies and the environmental jeopardy associated to the occurrence. In this sense, SEM-based mineralogy has an enormous potential in environment studies.
      Citation: Minerals
      PubDate: 2022-06-03
      DOI: 10.3390/min12060716
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 717: Fluid-Induced Inhomogeneous Cr-spinel in
           Dunite and Wehrlite from the Duke Island Complex, Southeastern Alaska

    • Authors: Yang Luo, Ben-Xun Su, Joyashish Thakurta, Yan Xiao, Yang Bai
      First page: 717
      Abstract: Cr-spinel [(Mg, Fe2+)(Cr, Al, Fe3+)2O4)] is a common mineral in the ultramafic core of the Duke Island complex in southeastern Alaska, US. Cr-spinel grains with an unmixed texture have been observed in dunite and wehrlite of the complex. Inhomogeneous Cr-spinel with a ratio of Cr/(Al + Cr + Fe3+) <0.37 is prominent in dunite. The inhomogeneous Cr-spinel consists of two completely different compositions: Al-rich Cr-spinel, and Fe3+-rich Cr-spinel with a wide range of Cr content (from 11.8 wt.% to 28.6 wt.% Cr2O3). The unmixed texture is complex, and three subtypes of inhomogeneous Cr-spinel are recognized: Type B1 Cr-spinel showing complete separation, crystallographically oriented type B2 Cr-spinel, and irregular Al-rich Cr-spinel rimmed type B3 Cr-spinel. The unmixed texture was achieved by an unmixing process at around 600 °C due to the miscibility gap of spinel between Al-rich and Fe3+-rich phases. The unmixed patterns of inhomogeneous Cr-spinel are controlled by the initial chemical composition, grain size of the initial spinel, and the cooling process. We propose that the initial composition of inhomogeneous Cr-spinel was formed by the interaction of high-temperature fluid and olivine; Cr-spinel that experienced unmixing may be a useful proxy to unveil the activity of high-temperature fluid in the formation of Alaskan-type complexes.
      Citation: Minerals
      PubDate: 2022-06-03
      DOI: 10.3390/min12060717
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 718: Mechanism and Kinetics of Stibnite
           Dissolution in H2SO4-NaCl-Fe(SO4)1.5-O2

    • Authors: Rafael Padilla, Oscar Caro, Dennis Vega-Garcia, María C. Ruiz
      First page: 718
      Abstract: This paper is concerned with the kinetics of stibnite (Sb2S3) dissolution in H2SO4-NaCl-Fe(SO4)1.5-O2 solutions. The experimental results of our study showed a positive effect from ferric ions on stibnite dissolution of up to 0.05 M. An increase in H2SO4 concentration from 0.8 to 3 M and NaCl concentration from 0 to 3 M NaCl improved the stibnite dissolution. In solutions without ferric ions, the leaching occurs by the acid dissolution reaction producing H2S without forming elemental sulfur, as we confirmed by the X-ray diffraction (XRD) analysis of leach residues. In this case, the kinetic data was analyzed using a shrinking core model controlled by a chemical reaction, and the calculated activation energy was 54.6 kJ/mol. Conversely, in the presence of ferric ions, the XRD patterns of the leach residues showed large peaks for elemental sulfur, confirming that the stibnite was oxidized and formed a sulfur porous layer. The mechanism in the presence of ferric ions involved an acid dissolution reaction, with the diffusion of the reactant/product species through the porous product layer, followed by the oxidation of H2S by ferric ions. The kinetic data were analyzed using a diffusion-controlled model, and the activation energy was 123.8 kJ/mol. This high activation value is consistent with the proposed mechanism.
      Citation: Minerals
      PubDate: 2022-06-03
      DOI: 10.3390/min12060718
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 719: Ductile vs. Brittle Strain Localization
           Induced by the Olivine–Ringwoodite Transformation

    • Authors: Julien Gasc, Blandine Gardonio, Damien Deldicque, Clémence Daigre, Arefeh Moarefvand, Léo Petit, Pamela Burnley, Alexandre Schubnel
      First page: 719
      Abstract: As it descends into the Earth’s mantle, the olivine that constitutes the lithosphere of subducting slabs transforms to its high-pressure polymorphs, wadsleyite and ringwoodite, in the so-called transition zone. These transformations have important rheological consequences, since they may induce weakening, strain localization, and, in some cases, earthquakes. In this study, germanium olivine (Ge-olivine) was used as an analogue material to investigate the rheology of samples undergoing the olivine–ringwoodite transformation. Ge-olivine adopts a ringwoodite structure at pressures ~14 GPa lower than its silicate counterpart does, making the transformation accessible with a Griggs rig. Deformation experiments were carried out in a new-generation Griggs apparatus, where micro-seismicity was recorded in the form of acoustic emissions. A careful analysis of the obtained acoustic signal, combined with an extensive microstructure analysis of the recovered samples, provided major insights into the interplay between transformation and deformation mechanisms. The results show that significant reaction rates cause a weakening via the implementation of ductile shear zones that can be preceded by small brittle precursors. When kinetics are more sluggish, mechanical instabilities lead to transformational faulting, which stems from the unstable propagation of shear bands localizing both strain and transformation. The growth of these shear bands is self-sustained thanks to the negative volume change and the exothermic nature of the reaction, and leads to dynamic rupture, as attested by the acoustic emissions recorded. These micro-earthquakes share striking similarities with deep focus earthquakes, which may explain several seismological observations such as magnitude frequency relations and the occurrence of deep repeating earthquakes and foreshocks.
      Citation: Minerals
      PubDate: 2022-06-04
      DOI: 10.3390/min12060719
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 720: Major and Trace-Element Chemistry of
           Cr-Spinel in Upper Mantle Xenoliths from East Antarctica

    • Authors: Alexandre V. Andronikov, Irina E. Andronikova, Ondrej Pour
      First page: 720
      Abstract: Cr-spinels in the upper mantle peridotite xenoliths from two Late Mesozoic intrusions of alkaline-ultramafic rocks in Jetty Peninsula (East Antarctica) were studied in situ for their major and trace-element compositions by SEM and LA-ICP-MS. The upper mantle xenoliths were collected from the magmatic bodies “sampled” from different upper mantle domains. One domain was represented by mostly lherzolites (Cpx-poor Spl, Cpx-rich Spl and Spl-Grt) and another one by Spl harzburgites and dunites. Spinels occur as grains of different shapes, sizes and origins. Three main textural types of spinel were identified: primary spinel represented by clean homogeneous grains, a rim of recrystallization/resorption surrounding primary spinel grains and irregular interstitial resorbed grains. Primary spinels are characterized by the concentrations of Al2O3 21–51 wt%, MgO 15–20 wt%, FeO 10–24 wt% and Cr2O3 14–37 wt% with the Cr# of 0.16–0.54. Most trace elements are present in spinels in very low amounts. Only Ti, V, Mn, Co, Ni, Zn and Ga display concentrations in the range of tens to hundreds (up to thousands) ppm. Concentrations of other trace elements vary from below the detection limit to <10 ppm. Spinel major oxide and trace element features allowed the suggestion that the studied upper mantle peridotites represent both simple melt residues and residues strongly influenced by the MORB-like and the SSZ-related melts. The MORB-like melts may be related to the beginning of the Lambert–Amery rift system development, whereas SSZ-like melts could be related to reactivation of SSZ material buried during much earlier amalgamation of East Antarctica.
      Citation: Minerals
      PubDate: 2022-06-04
      DOI: 10.3390/min12060720
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 721: Review on the Art of Roof Contacting in
           Cemented Waste Backfill Technology in a Metal Mine

    • Authors: Fengbin Chen, Jiguang Liu, Xiaowei Zhang, Jinxing Wang, Huazhe Jiao, Jianxin Yu
      First page: 721
      Abstract: The backfilling mining method can effectively solve the environmental and safety problems caused by mining. It is the key technology to realize green mining. Scientific development has accelerated the pace of research on the rational utilization of mine solid waste and improved the research level of backfilling technology. The development history of the backfilling mining method is introduced in the present paper, and it is determined that roof-contacting backfilling is the key technology of mine-solid-waste backfilling mining. This paper introduces three calculation methods of similar roof-contacted backfilling rates. In this paper, the relationship between the characteristics of backfilling slurry made from solid waste from mines and the roof-contacted backfilling rate is systematically analyzed, such as the flow law in stope (gravity gradient), bleeding shrinkage, and natural sedimentation of backfilling slurry. It is pointed out that the characteristics of the stope, such as washing-pipe water, water for the leading way, filling pipeline, and shape of the backfilling stope, are closely related to the roof-contacted backfilling rate. The influential relationship between objective factors, such as human factors, limited auxiliary leveling measures, and backfilling “one-time operation” in the backfilling process, and high-efficiency top filling are considered, and a schematic diagram of the influencing top-filling rate and structure is drawn. At the same time, this paper summarizes the improvement measures of roof connection from three aspects. These include the use of expansive non-shrinkable materials, forced roof-contacted technology, and strengthening management level. It is pointed out that the roof-contacted filling technology is still facing severe challenges, and the research on the backfilling connection technology needs to be strengthened.
      Citation: Minerals
      PubDate: 2022-06-04
      DOI: 10.3390/min12060721
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 722: Mechanical Properties and Acoustic Emission
           Characteristics of Unloading Instability of Sandstone under High Stress

    • Authors: Zhiyuan Hou, Fukun Xiao, Gang Liu, Oleg Viktorovich Bashkov, Lan Lyu
      First page: 722
      Abstract: In order to analyze the law of unloading instability of deep rock mass, the unloading experiment of sandstone under different confining pressures was carried out, and the mechanical properties and acoustic emission characteristics of sandstone unloading failure under high stress were obtained. The results demonstrate that before unloading, the sandstone under low stress shows compression and elastic deformation, whereas that under high stress shows elastic deformation and plastic deformation. Moreover, the unloading behavior of sandstone under low stress is ductile, whereas that under high stress is brittle. Poisson’s ratio and elastic modulus have negative and positive correlation with initial confining pressure, respectively. During unloading, the higher the initial confining pressure is, the earlier the rock sample damage occurs. Prior to the accelerated damage stage, the unloading amount and AE cumulative count are inversely proportional and directly proportional to the initial confining pressure, respectively. The simultaneous occurrence of UHF, HF, MF, and LF in the AE power spectrum, as well as a steep increase in fractal dimension followed by a decrease, can be used as precursors to unloading instability in sandstone.
      Citation: Minerals
      PubDate: 2022-06-05
      DOI: 10.3390/min12060722
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 723: Development of a Sustainable Process for
           Complex Sulfide Ores Containing Anglesite: Effect of Anglesite on
           Sphalerite Floatability, Enhanced Depression of Sphalerite by Extracting
           Anglesite, and Recovery of Extracted Pb2+ as Zero-Valent Pb by Cementation
           Using Zero-Valent Fe

    • Authors: Kosei Aikawa, Mayumi Ito, Atsuhiro Kusano, Sanghee Jeon, Ilhwan Park, Naoki Hiroyoshi
      First page: 723
      Abstract: The presence of anglesite (PbSO4) in complex sulfide ores negatively affects the separation of Cu-Pb sulfides and sphalerite (ZnS) due to lead activation, and PbSO4 rejected to tailings dams contaminates the surrounding environment with lead. To address these problems, this study investigated the application of ethylene diamine tetra acetic acid (EDTA) pretreatment extracting PbSO4 to ZnS flotation and the recovery of the extracted Pb2+ as zero-valent Pb by cementation using zero-valent iron (ZVI). The application of EDTA pretreatment could extract ~99.8% of PbSO4, thus depressing ZnS floatability from 82% to 30%. In addition, cementation using ZVI could recover ~99.7% of Pb2+ from the leachate of EDTA pretreatment.
      Citation: Minerals
      PubDate: 2022-06-06
      DOI: 10.3390/min12060723
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 724: The Calcite-Dolomite Solvus Temperature and
           T-X(CO2) Evolution in High-Grade Impure Marble from Thongmön Area,
           Central Himalaya: Implications for Carbon Cycling in Orogenic Belts

    • Authors: Xueqian Chen, Lifei Zhang, Guibin Zhang, Zeng Lü
      First page: 724
      Abstract: Impure dolomitic marble from the Great Himalayan Sequences (GHS) in Thongmön area, central Himalaya, is first systematically reported here concerning its petrographic features, textural relations, and fluid evolution. The Thongmön impure marble is characterized by the assemblage of calcite + dolomite + forsterite + spinel + phlogopite + clinohumite ± diopside ± retrograde serpentine. Three groups of calcite and dolomite occurring both as inclusions and in the matrix were identified: group I is represented by relatively magnesium-rich calcite (Cal) (CalI:XMg = 0.10–0.15) and almost pure dolomite (Dol) (DolI:XMg = 0.47–0.48), corresponding to the Cal-Dol solvus temperatures of 707–781 °C; group II is characterized by vermicular dolomite exsolutions (DolII:XMg = 0.45–0.46) in Mg-rich calcite and Mg-poor calcite (CalII:XMg = 0.05–0.08) adjacent to DolII, and the recorded solvus temperatures are 548–625 °C; group III is represented by nearly pure calcite (CalIII:XMg = 0.003–0.02) and Ca-rich dolomite in the matrix (DolIII:XMg = 0.33–0.44). Isobaric T-X(CO2) pseudosection at a peak pressure of 15 kbar in the system K2O-CaO-MgO-Al2O3-FeO-SiO2-H2O-CO2 suggests that the peak fluid composition of the Thongmön forsterite marble is restricted to X(CO2) < 0.04 at T > 780 °C due to a potential infiltration event of H2O-rich fluid. Alternatively, the forsterite marble is a retrograde product subordinated to the GHS exhumation process, and its fluid composition is relatively CO2-rich (0.6 < X(CO2) < 0.8 at 5 kbar, 750 °C) at a nearly isothermal decompression stage. In either case, we suggest that the carbon flux contributed by metacarbonate rocks in an orogen setting to the global carbon cycling must be considered.
      Citation: Minerals
      PubDate: 2022-06-06
      DOI: 10.3390/min12060724
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 725: Efficient Separation of Ultrafine Coal
           Assisted by Selective Adsorption of Polyvinylpyrrolidone

    • Authors: Yujie Mei, Qiuyu Lin, Changning Wu, Wei Huang, Daofan Cao, Ke Liu
      First page: 725
      Abstract: The efficient separation of ultrafine coal is a challenging process due to the ultrafine particle size and gangue entrainment. In this study, a polymer, polyvinylpyrrolidone (PVP), was introduced as a regulator for ultrafine coal beneficiation. The addition of PVP improved the combustible recovery of clean coal and decreased the ash content. This effect was also presented by the selectivity index. The regulation mechanism of PVP was investigated using diverse methods. The adsorption tests performed demonstrated the adsorption amount of PVP on coal, kaolinite, and quartz, which were related to the increase in the separation efficiency. A zeta potential analyzer was employed to elucidate the effect of PVP on the electrical properties of ultrafine particles. The results revealed that the electrokinetic potential of mineral was sensitive to the varying PVP concentration. The particle size distribution was observed to value the influence of PVP on the particle behavior, which was tested by a laser particle size analyzer. X-ray photoelectron spectroscopy was used to investigate the surface elemental compositions of coal, kaolinite, and quartz, which were regulated by the adsorption of PVP. This research is beneficial to understanding the role of PVP as regulators and provides a basis for the efficient separation of ultrafine coal.
      Citation: Minerals
      PubDate: 2022-06-06
      DOI: 10.3390/min12060725
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 726: Thermal Transformation of Natural
           Schwertmannite in the Presence of Chromium

    • Authors: Carlos Lázaro, Juan Antelo, Ivan Carabante, Alba Otero-Fariña, Pedro V. Verdes, Bruno Dacunha-Marinho, Sarah Fiol
      First page: 726
      Abstract: Schwertmannite is a metastable mineral playing a crucial role in the immobilization of metal(oid)s in acid mine drainage (AMD) systems. High temperatures associated with wildfires could lead to a sudden schwertmannite transformation, changing the mobility of metal(oid)s. The objective of the present study was to examine the thermal transformation from schwertmannite to hematite, and the subsequent effect on the chromium partitioning. The immobilization of arsenate after thermal transformation and its implications on chromium mobility was also evaluated. Natural schwertmannite, with increasing contents of chromium, was thermally treated between 200 to 800 °C. Transformation products were characterized by solid-phase techniques and selective chemical extractions. Results indicated a transformation to hematite at temperatures above 400 °C. The presence of chromium barely affected the temperature at which the transformation occurred, although partitioning of chromium in the mineral changed with temperature. As the temperature increased from 25 °C to 400 °C, chromium was less mobile and less outcompeted by arsenic adsorption, suggesting a larger contribution of inner-sphere complexes with increasing temperature. At temperatures above 600 °C, non-mobile forms strongly associated with neo-formed hematite were found. Finally, neo-formation of hematite led to a decrease in arsenic adsorption, implying a potentially enhanced arsenic mobility in AMD systems upon wildfires.
      Citation: Minerals
      PubDate: 2022-06-06
      DOI: 10.3390/min12060726
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 727: Pre-Processing to Increase the Capacity of
           SAG Mill Circuits—Case Study

    • Authors: Homero Delboni, Evandro Costa e Silva, Vladmir Kronemberger Alves, Ana Carolina Chieregati
      First page: 727
      Abstract: This paper describes the adopted approach for increasing the capacity of an existing industrial grinding circuit by adapting the respective configuration to process the ore from a new mine. Accordingly, due to Sossego mine exhaustion, Vale S. A. decided to use the existing industrial facilities and infrastructure for processing the Cristalino ore deposit located in Para state, within the Brazilian Amazon. Considering the higher hardness of Cristalino ore compared to Sossego ore, a reduction in capacity in the existing SAG grinding circuit was anticipated. A comprehensive grinding pilot plant campaign was conducted with a characterization program including 98 Cristalino ore samples, as described throughout this paper. Sossego grinding circuit was also surveyed for mathematical modeling and simulations to assess such an estimative further. The mathematical model calibration for setting different circuit configurations and operating conditions to enhance the circuit’s capacity was based on the combination of pilot plant results and ore characterization. Simulations indicated that a capacity increase of 12% would be achieved in the existing grinding circuit by further crushing 35% of SAG mill fresh feed. Such figures would represent yearly additions of 8.3 kt in copper and 250 kg in gold productions.
      Citation: Minerals
      PubDate: 2022-06-06
      DOI: 10.3390/min12060727
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 728: Uranium Retardation Capacity of Lithologies
           from the Negev Desert, Israel—Rock Characterization and Sorption

    • Authors: Martin A. Dangelmayr, Gilles Y. Bussod, Paul W. Reimus, Giday WoldeGabriel, Ran Calvo, Rose J. Harris, Philip H. Stauffer, Hakim Boukhalfa, Ofra Klein-BenDavid, Noa Balaban, Ravid Rosenzweig
      First page: 728
      Abstract: A series of batch experiments were performed to assess the uranium sorption capacity of four mineralogically distinct lithologies from the Negev Desert, Israel, to evaluate the suitability of a potential site for subsurface radioactive waste disposal. The rock specimens consisted of an organic-rich phosphorite, a bituminous marl, a chalk, and a sandstone. The sorption data for each lithology were fitted using a general composite surface complexation model (GC SCM) implemented in PHREEQC. Sorption data were also fitted by a non-mechanistic Langmuir sorption isotherm, which can be used as an alternative to the GC SCM to provide a more computationally efficient method for uranium sorption. This is because all the rocks tested have high pH/alkalinity/calcium buffering capacities that restrict groundwater chemistry variations, so that the use of a GC SCM is not advantageous. The mineralogy of the rocks points to several dominant sorption phases for uranyl (UO22+), including apatite, organic carbon, clays, and iron-bearing phases. The surface complexation parameters based on literature values for the minerals identified overestimate the uranium sorption capacities, so that for our application, an empirical approach that makes direct use of the experimental data to estimate mineral-specific sorption parameters appears to be more practical for predicting uranium sorption.
      Citation: Minerals
      PubDate: 2022-06-06
      DOI: 10.3390/min12060728
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 729: Nature and Isomorphism of Extra-Framework
           Components in Cancrinite- and Sodalite-Related Minerals: New Data

    • Authors: Nikita V. Chukanov, Marina F. Vigasina, Roman Yu. Shendrik, Dmitry A. Varlamov, Igor V. Pekov, Natalia V. Zubkova
      First page: 729
      Abstract: New data on the isomorphism of extra-framework components (including chromophores) in two- and multilayer minerals belonging to the cancrinite and sodalite groups, are obtained using chemical and single-crystal X-ray diffraction data as well as infrared, Raman, ESR, UV–Vis–near IR absorption and photoluminescence spectroscopy methods. It is shown that the blue color of these minerals may be due to CO3•− or S3•− radical anions, whereas yellow and pink shadings are typically due to the presence of S2•− radical anions and S4•− or S4, respectively. Two kyanoxalite varieties are distinguished: (1) with predominantly acid oxalate groups and (2) predominantly neutral oxalate groups. Zundel cation H5O2+ and CO2 molecules are shown to be typical impurities in nosean. The Zundel cation is also detected in kyanoxalite and in the 12-layer, cancrinite-related mineral marinellite. Wide isomorphic series involving substitutions of SO4− for SO32− and CO32−, as well as OH− for H2O and F−, are common for eight-layer, cancrinite-group minerals with an afghanite-type framework.
      Citation: Minerals
      PubDate: 2022-06-07
      DOI: 10.3390/min12060729
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 730: Effects of Recycled Sponge Iron on
           Phosphorus Recovery from Polluted Water

    • Authors: Ping Cheng, Biao Wang, Xiaohuan Wang, Wei Xiao
      First page: 730
      Abstract: Phosphorus in water not only degrades water quality but also leads to a waste of resources. In this study, adsorption thermodynamics and kinetics were used to study the effect of sponge iron on phosphorus removal, and a filtration bed was used to simulate the phosphorus removal in polluted water. The results showed that the maximum theoretical adsorption capacity of the modified sponge iron was increased from 4.17 mg/g to 18.18 mg/g. After desorption with 18.18 mol/L of sodium hydroxide and reactivation with 6% (w%) sulfuric acid, the activation rate of modified sponge iron can reach 98%. In a continuous operation experiment run for approximately 200 days, the sponge iron phosphorus removal percolation bed showed a good phosphorus removal ability. Under the condition of TP = 10 mg/L, HRT = 1 H, the comprehensive phosphorus removal rate was 30–89%, and the accumulated phosphorus adsorption per unit volume was 6.95 kg/m3. Wastewater from the regeneration of the sponge iron base can be used to recover guano stone. The optimum conditions were pH = 10, n (Mg2+):n (PO43−):n (NH4+) = 1.3:1:1.1. Under the optimum conditions, the phosphorus recovery rate could reach 97.8%. The method provided in this study has theoretical and practical significance for the removal and recycling of phosphorus in polluted water.
      Citation: Minerals
      PubDate: 2022-06-07
      DOI: 10.3390/min12060730
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 731: Assessment of Machine Learning Models for
           the Prediction of Rate-Dependent Compressive Strength of Rocks

    • Authors: Ziquan Yang, Yanqi Wu, Yisong Zhou, Hui Tang, Shanchun Fu
      First page: 731
      Abstract: The prediction of rate-dependent compressive strength of rocks in dynamic compression experiments is still a notable challenge. Four machine learning models were introduced and employed on a dataset of 164 experiments to achieve an accurate prediction of the rate-dependent compressive strength of rocks. Then, the relative importance of the seven input features was analyzed. The results showed that compared with the extreme learning machine (ELM), random forest (RF), and the original support vector regression (SVR) models, the correlation coefficient R2 of prediction results with the hybrid model that combines the particle swarm optimization (PSO) algorithm and SVR was highest in both the training set and the test set, both exceeding 0.98. The PSO-SVR model obtained a higher prediction accuracy and a smaller prediction error than the other three models in terms of evaluation metrics, which showed the possibility of the model as a rate-dependent compressive strength prediction tool. Additionally, besides the static compressive strength, the stress rate is the most important influence factor on the rate-dependent compressive strength of the rock among the listed input parameters. Moreover, the strain rate has a positive effect on the rock strength.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060731
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 732: Dissolution Behavior of Sodium Phosphate in
           a Na3PO4–Na2WO4–NaOH Solution System

    • Authors: Bing-Xuan He, Yong Liang, Ze-Kun Fan, Lue-Wei Xu, De-Gang Liu, Guo-Zuan Xu
      First page: 732
      Abstract: Sodium hydroxide autoclaving is the main method for smelting scheelite in China. In this method, sodium phosphate is added as an additive to realize the highly efficient decomposition of scheelite, and a crude sodium tungstate solution containing sodium phosphate and sodium hydroxide is obtained. In the subsequent process of ion exchange, phosphorus ions in the solution compete with the resin adsorption of tungstate, which reduces the adsorption capacity of the resin and endangers the purity of the subsequent sodium tungstate solution. To remove the phosphorus from crude sodium tungstate solution, a chemical purification method is usually adopted. The principle of the chemical purification method is to use chemical reagents to react with impurities to form precipitates to achieve the purpose of impurity removal. Because of the advantages of simple industrial implementation and high impurity removal efficiency, it has been widely used in phosphorus removal from crude sodium tungstate solution. However, in the process of phosphate removal in a crude sodium phosphate solution, the chemical purification method has some disadvantages. First, the additional cost of chemical reagents is required, and other metal impurities from chemical reagents would be introduced to crude sodium tungstate solution. Second, phosphate impurity removed by the chemical precipitation method is usually sedimented in other forms but sodium phosphate, which makes the phosphate resource unable to be recycled for tungsten smelting. Therefore, a novel phosphorus removal method needs to be developed. The dissolution behavior of sodium phosphate in a Na3PO4–Na2WO4–NaOH system was investigated in this paper. The results showed that in binary or ternary solution systems of sodium phosphate, sodium tungstate, and sodium hydroxide, the common-ion effect and salt effect exist simultaneously. The common-ion effect decreases the solubility of sodium phosphate, while the salt effect increases the solubility of sodium phosphate. Increasing the concentration of sodium hydroxide or sodium tungstate and lowering the temperature of the solution can greatly reduce the phosphorus concentration in crude sodium tungstate solution, making the crude sodium tungstate solution meet industrial requirements of ion exchange. The results of the study lay a theoretical foundation for the development of new phosphorus removal methods.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060732
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 733: LA-ICP-MS Mapping of Barren Sandstone from
           the Proterozoic Athabasca Basin (Canada)—Footprint of U- and
           REE-Rich Basinal Fluids

    • Authors: Guoxiang Chi, Eric G. Potter, Duane C. Petts, Simon Jackson, Haixia Chu
      First page: 733
      Abstract: The Proterozoic Athabasca Basin hosts a large number of high-grade, large-tonnage unconformity-related uranium (U) deposits, many of which are also enriched in rare earth elements (REE). The basin also contains hydrothermal REE mineralization unassociated with U. Previous studies postulated that U and REE were derived from either the basin or the basement; however, the exact source of the metals remains ambiguous. This study provides evidence of U- and REE-rich fluids throughout the Athabasca Basin through laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) mapping of barren sandstone distal to mineralized areas. The results indicate that elevated U and REE concentrations mainly occur in the matrix; there are strong positive correlations between U and REE, Th, P and Sr, and moderate positive correlations between U and Zr, Ba, Fe, Al, K and Ca, but the few spots with the highest U are unrelated to these elements. Quantitative evaluation of the element correlations, together with scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis, suggests that most of the elevated U and REE are hosted in aluminum phosphate sulfate (APS) minerals rather than apatite and monazite. As the APS minerals are of diagenetic-hydrothermal origin, the results testify to the presence of U- and REE-rich fluids within the Athabasca Basin. The elevated Th/U ratio (~10) and REE pattern (strong heavy rare earth element (HREE) depletion) are consistent with a model in which large amounts of U and REE (especially HREE) were leached from the sandstone within the Athabasca Basin and contributed to U and REE mineralization near the unconformity between the sedimentary rocks in the basin and underlying basement rocks. This study demonstrates that LA-ICP-MS mapping can be effectively used to evaluate microscale distribution of elements and their mobility in sedimentary rocks to address mineralization related problems.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060733
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 734: Three-Dimensional Magnetotelluric Inversion
           for Triaxial Anisotropic Medium in Data Space

    • Authors: Jingtao Xie, Hongzhu Cai, Xiangyun Hu, Shixin Han, Minghong Liu
      First page: 734
      Abstract: The interpretation of three-dimensional (3-D) magnetotelluric (MT) data is usually based on the isotropic assumption of the subsurface structures, and this assumption could lead to erroneous interpretation in the area with considerable electrical anisotropy. Although arbitrary anisotropy is much closer to the ground truth, it is generally more challenging to recover full anisotropy parameters from 3-D inversion. In this paper, we present a 3-D triaxial anisotropic inversion framework using the edge-based finite element method with a tetrahedral mesh. The 3-D inverse problem is solved by the Gauss-Newton (GN) method which shows fast convergence behavior. The computation cost of the data-space method depends on the size of data, which is usually smaller than the size of model; therefore, we transform the inversion algorithm from the model space to the data space for memory efficiency. We validate the effectiveness and applicability of the developed algorithm using several synthetic model studies.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060734
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 735: The Effect of Different Outer Cations on the
           Stability of Fluorotitanium Complex

    • Authors: Junfeng Liu, Xugang Zuo, Haotian Liu
      First page: 735
      Abstract: Fluoride-rich fluid is believed to be able to activate and migrate Ti and other high field-strength elements to the greatest extent. The stability of F-rich titanium complexes can ensure their migration in the fluid, but is inseparable from the physical and chemical properties of the fluid, such as concentration, temperature and pH value—important factors affecting the stability of the complexes. In this study, the influence of the outer cationic complex fluid on the stability of the fluorine titanium complex was studied. Studies were based on different kinds of fluorine titanium complex (K2TiF6, Na2TiF6, (NH4)2TiF6 and H2TiF6) in 100 MPa pressure. Under the condition of 200~500 °C temperature, we found that as the temperature rises, the hydrolysis of F-rich titanium complexes is violent. We compared the stability of four F-titanium complexes with different outer cations according to the hydrolysis rate and the cumulative hydrolysis equilibrium constant. We compared the F-titanium complexes with alkali metal as the outer cations that are more stable, such as K2TiF6 and Na2TiF6. However, the F-rich titanium complex in an acidic fluid is relatively unstable, which is not conducive to the migration of Ti elements. Due to the water–rock reactions that occur in hydrothermal fluid migration, mixing and alteration, once in the hydrothermal system, the fluid composition, pH value and temperature change. Thus, the F-titanium complex becomes extremely unstable, leading to the precipitation of titanium from the hydrothermal fluid and the growth of Ti-rich minerals.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060735
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 736: Control Structure Design Using Global
           Sensitivity Analysis for Mineral Processes under Uncertainties

    • Authors: Oscar Mamani-Quiñonez, Luis A. Cisternas, Teresa Lopez-Arenas, Freddy A. Lucay
      First page: 736
      Abstract: Multiple-input and multiple-output (MIMO) systems can be found in many industrial processes, including mining processes. In practice, these systems are difficult to control due to the interactions of their input variables and the inherent uncertainty of industrial processes. Depending on the interactions in the MIMO process, different control strategies can be implemented to achieve the desired performance. Among these strategies is the use of a decentralized structure that considers several subsystems and for which a SISO controller can be designed. In this study, a methodology based on global sensitivity analysis (GSA) to design decentralized control structures for industrial processes under uncertainty is presented. GSA has not yet been applied for this purpose in process control; it allows us to understand the dynamic behavior of systems under uncertainty in a broad value range, unlike approaches proposed in the literature. The proposed GSA is based on the Sobol method, which provides sensitivity indices used as interaction measures to establish the input–output pairing for MIMO systems. Two case studies based on a semi-autogenous grinding (SAG) mill and a solvent extraction (SX) plant are presented to demonstrate the applicability of the proposed methodology. The results indicate that the methodology allows the design of 2 × 2 and 3 × 3 decentralized control structures for the SAG mill and SX plant, respectively, which exhibit good performance compared to MPC. For example, for the SAG mill, the determined pairings were fresh ore flux/fraction of mill filling and power consumption/percentage of critical speed.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060736
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 737: A Review of the G4 “Tin
           Granites” and Associated Mineral Occurrences in the Kivu Belt
           (Eastern Democratic Republic of the Congo) and Their Relationships with
           the Last Kibaran Tectono-Thermal Events

    • Authors: Michel Villeneuve, Nandefo Wazi, Christian Kalikone, Andreas Gärtner
      First page: 737
      Abstract: The Mesoproterozoic Kibaran belts host large amounts of mineral resources such as cassiterite, wolframite, gold, and columbite-group minerals (“coltan”), all of them in high demand for new technologies and related industries. Most of these mineral occurrences are linked to the latest Mesoproterozoic to early Neoproterozoic G4 granitoid intrusions, also termed “tin(-bearing) granites”. Three main parts constitute the Kibaran belts: the Kibaride Belt (KIB) in the south, the Karagwe-Ankole Belt (KAB) in the east, and the Kivu Belt (KVB) in the west. Geological detail concerning the metallogeny of the KVB, which hosts large parts of these mineral resources, is very sparse. Previously, there was an assumed time gap of about 200 Ma between the formation of the last Kibaran terranes (1250 to 1200 Ma) and the emplacement of the G4 granites (ca. 1050 to 970 Ma), which generated the main mineralizations. Recent studies dated the last Kibaran tectono-thermal events younger than 1120 to 1110 Ma, which gave evidence for a drastic reduction in this time gap. Thus, the two newly recognized tectono-thermal events have likely contributed to the remobilization of older mineralized granites. These new data allow us to link the G4 granitoids and the associated mineralizations with the terminal Kibaran orogeny. However, the G4 emplacement and its relationships with older granites, with their host rocks and associated mineralizations, are not yet understood. Here, the main occurrences of the KVB are reviewed, and comparisons with similar mineralizations in the adjacent KAB are undertaken to improve our understanding on these complex relationships.
      Citation: Minerals
      PubDate: 2022-06-08
      DOI: 10.3390/min12060737
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 738: Closure of the Eastern Paleo-Asian Ocean:
           Constraints from the Age and Geochemistry of Early Permian Zhaojinggou
           Pluton in Inner Mongolia (North China)

    • Authors: Guang-Yao Li, Liang Qiu, Zhi-Dan Li, Lei Gao, Chao Fu, Jia-Ying Wang, Qi Zhang, Jia-Run Tu, Teng-Fei Ge
      First page: 738
      Abstract: The closing time of the Paleo-Asian Ocean and the tectonic evolution of the northern margin of the North China Craton are still controversial. The geochronology and geochemistry of the Zhaojinggou monzogranite pluton provide new constraints on the late Paleozoic tectonic evolution and the closure time of the Paleo-Asian Ocean in the southern Central Asian Orogenic Belt (CAOB). The monzogranite yielded a zircon U-Pb age of 286.7 ± 1.2 Ma. Due to the characteristics of low–moderate Mg# values (25.87–39.21), low Fe2O3T values (1.13–1.72), and A/CNK > 1, we show that the pluton is weak peraluminous, high in potassium calc–alkaline series, and displays the feature of S-type granite. The total REE content is low, the distribution curve is right dipping, and the LREE is enriched; the δEu average value is 1.32 (1.11–1.54). The granite presents relatively high (87Sr/86Sr)i values of 0.712345–0.713723, low εNd(t) values of −8.89–−8.21 (an average value of −8.56), and a TDM2 of 1718–1773 Ma. Furthermore, the zircon in situ Hf isotopic analysis shows 176Hf/177Hf ratios of 0.282342 to 0.282614, low εHf(t) values of −9.27–0.38 (mean −4.74), and a TDM2 of 1275–1887 Ma. Additionally, high field strength elements such as Nb, Ta, and Ti are depleted, and large ion lithophile elements, e.g., Rb, Ba, K, and Sr, are enriched. The above features of the Zhaojinggou monzogranite indicate that the pluton was derived from late Paleoproterozoic to Mesoproterozoic lower crustal mafic materials. By discussing the genesis and tectonic implications of the pluton massif, we propose that the Zhaojinggou monzogranite represents a magmatic event caused by the crustal–mantle interaction during the southward subduction of the eastern Paleo-Asian Ocean in the northern margin of the North China Craton during the Early Permian.
      Citation: Minerals
      PubDate: 2022-06-09
      DOI: 10.3390/min12060738
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 739: 3D Sedimentary Architecture of Sandy Braided
           River, Based on Outcrop, Unmanned Aerial Vehicle and Ground Penetrating
           Radar Data

    • Authors: Wei Guo, Chunmei Dong, Chengyan Lin, Tao Zhang, Zhongxiang Zhao, Jia Li
      First page: 739
      Abstract: Ground Penetrating Radar (GPR) is a geophysical method that uses antennas to transmit and receive high-frequency electromagnetic waves to detect the properties and distribution of materials in media. In this paper, geological observation, UAV detection and GPR technology are combined to study the recent sediments of the Yungang braided river study area in Datong. The application of the GPR technique to the description of fluvial facies and reservoir architecture and the development of geological models are discussed. The process of GPR detection technology and application includes three parts: GPR data acquisition, data processing and integrated interpretation of GPR data. The geological surface at different depths and scales can be identified by using different combinations of frequencies and antenna configurations during acquisition. Based on outcrop observation and lithofacies analysis, the Yandong Member of the Middle Jurassic Yungang Formation in the Datong Basin has been identified as a typical sandy braided river sedimentary system. The sandy braided river sandbody changes rapidly laterally, and the spatial distribution and internal structure of the reservoir are very complex, which has a very important impact on the migration and distribution of oil and gas as a reservoir. It is very important to make clear the characteristics of each architectural unit of the fluvial sand body and quantitatively characterize them. The architectural elements of the braided river sedimentary reservoir in the Datong-Yungang area can be divided into three types: Channel unit, bar unit and overbank assemblages. The geological radar response characteristics of different types of sedimentary units are summarized and their interfaces are identified. The channel sediments form a lens-shaped wave reflection with a flat at the top and convex-down at the bottom in the radar profile, and the angles of the radar reflection directional axes are different on both sides of the sedimentary interface. In the radar profile, the deposit of the unit bar is an upward convex reflection structure. The overbank siltation shows a weak amplitude parallel reflection structure. The flood plain sediments are distributed continuously and stably in the radar profile, showing weak reflection characteristics. Different sedimentary units are identified by GPR data and combined with Unmanned Aerial Vehicle (UAV) detection data, and the establishment of the field outcrop geological model is completed. The development pattern of the diara is clarified, and the swing and migration of the channel in different stages are identified.
      Citation: Minerals
      PubDate: 2022-06-10
      DOI: 10.3390/min12060739
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 740: Origin of the Bleaching in Lower Cretaceous
           Continental Red Beds in the Uragen Zn–Pb Deposit, Xinjiang, NW
           China, and Its Implications for Zn–Pb Mineralization

    • Authors: Rongzhen Gao, Chunji Xue, Junfeng Dai, Ronghao Man
      First page: 740
      Abstract: The Uragen giant sandstone-hosted Zn–Pb deposit has a proven reserve of 5.90 Mt metals in the southern ore zone and potentially 10 Mt metals for the whole deposit, and orebodies are strictly confined to the bleached clastic rocks of the Lower Cretaceous red beds. The bleaching has been used to guide lead–zinc exploration; however, its nature and origin, as well as the relationship with Zn–Pb mineralization, remains unclear, although it is closely related to regional oil–gas infillings. Detailed field investigation and petrographic observation, TESCAN-integrated mineral analyzer (TIMA), and X-ray fluorescence (μ-XRF) analysis of the red and bleached sandstone at the same sedimentary layer demonstrate that the bleaching is mainly caused by the reductive dissolution of hematite pigment, which probably resulted from the interaction with H2S formed by in situ sulfate reduction during hydrocarbon migration. The calcite cements in the bleached sandstones show δ13C and δ18O values of −5.36~−5.94‰ and 20.94~27.91‰, respectively, and these samples fall close to the evolution line of decarboxylation of organic matter in δ13C-δ18O diagram, also suggesting a genetic relationship between the bleaching and hydrocarbon-bearing fluids. Petrol–mineral composition changes and sulfide characteristics of red, bleached, mineralized zones, as well as pyrite locally replaced by coarse-grained galena in the mineralized zone, imply that the bleaching may occurred before Zn–Pb mineralization. Mass balance calculation and μ-XRF analysis indicate that large amounts of Fe and minor Zn were extracted from red beds with little or no sulfates; however, the red beds with abundant sulfates may be a sink for leached ore metals during the bleaching process. We therefore propose that the former accumulations of iron sulfides and reduced sulfur in the bleached zones may provide an ideal chemical trap for later Zn–Pb mineralization, and the bleached zones with high ∑S contents are the favorable prospective targets of the Uragen-style sandstone-hosted Zn–Pb deposits.
      Citation: Minerals
      PubDate: 2022-06-10
      DOI: 10.3390/min12060740
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 741: Reduction of Acid Iron Ore Pellets under
           Simulated Wall and Center Conditions in a Blast Furnace Shaft

    • Authors: Mikko Iljana, Ahmed Abdelrahim, Hauke Bartusch, Timo Fabritius
      First page: 741
      Abstract: The operational conditions, including temperature and gas composition, vary along the radial position in a blast furnace. Nevertheless, very few studies can be found in the literature that discuss how the reduction behavior of the ferrous burden varies along the radial position. In this study, the effect of the radial charging position on the reducibility of acid iron ore pellets was investigated using a laboratory-scale, high-temperature furnace in CO-CO2-N2 and CO-CO2-H2-H2O-N2 atmospheres up to 1100 °C. The experimental conditions were accumulated based on earlier measurements from a multi-point vertical probing campaign that was performed for a center-working European blast furnace. The main finding of this study is that the pellet reduction proceeded faster under simulated blast furnace conditions resembling those in the center area, compared to the wall area, because of a higher share of CO and H2 in the gas. Therefore, the pellet charging position affects its reduction path in a blast furnace. Additionally, it was shown that the presence of H2 and H2O in the reducing gas enhanced the progress of reduction reactions significantly and enhanced the formation of cracks slightly, both of which are desirable in blast furnace operation. The reducibility data attained in this study are important in understanding how temperature and gas composition is connected to the reduction degree under realistic process conditions.
      Citation: Minerals
      PubDate: 2022-06-10
      DOI: 10.3390/min12060741
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 742: MSWI Fly Ash Multiple Washing: Kinetics of
           Dissolution in Water, as Function of Time, Temperature and Dilution

    • Authors: Caterina Caviglia, Enrico Destefanis, Linda Pastero, Davide Bernasconi, Costanza Bonadiman, Alessandro Pavese
      First page: 742
      Abstract: Municipal solid waste incineration fly ash (FA) can represent a sustainable supply of supplementary material to the construction industries if it is pre-treated to remove hazardous substances such as chloride, sulfate, and heavy metals. In this paper, the phenomenology associated with a water washing multi-cycle treatment of FA is investigated, focusing attention upon the mineral dissolution process. The efficacy of the treatment is assessed by leaching tests, according to the European Standard, and discussed in light of the occurring mineral phases. The water-to-solid (L/S) ratio is a crucial parameter, along with the number of washing cycles, for removing halite and sylvite, whereas quartz, calcite, anhydrite, and an amorphous phase remain in the solid residue. The sequential extraction method and dissolution kinetics modelling provide further elements to interpret leaching processes, and suggest that dissolution takes place through a two-step mechanism. Altogether, multi-step washing with L/S = 5 is effective in reducing contaminants under the legal limits for non-hazardous waste disposal, while the legal limits for non-reactive or reusable material cannot be completely reached, owing to sulfate and some heavy metals which still leached out from the residue.
      Citation: Minerals
      PubDate: 2022-06-10
      DOI: 10.3390/min12060742
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 743: Separation of Rare Earth and Aluminum by
           Selective Complexation

    • Authors: Jinhui Li, Yaoru Wen, Yuhang Chu, Wenxin Liu, Jinbiao Liu, Ruixiang Wang, Zhifeng Xu
      First page: 743
      Abstract: The presence of aluminum in the weathering crust leaching rare earth ore harms the subsequent extraction and separation of rare earths. High-quality rare earth production processes must reduce the aluminum content in their feed liquid. Groups containing lone pairs of electrons can form stable insoluble complexes with metal ions under certain conditions. In this paper, 3-hydroxyphenylphosphoryl propionic acid is used to selectively separate rare earths by complexation in feed liquid. The results show that: using 3-hydroxyphenylphosphoryl propionic acid as the complexing agent, and when the amount of 3-hydroxyphenyl phosphoryl propionic acid is six times the theoretical complete reaction amount, the reaction time is 10 min, the reaction temperature is 50 °C, and the solution is adjusted to pH 1, the extraction rate of RE3+ is 90.48%, and the extraction rate of Al3+ is nearly 9.52%. The separation of rare earth and aluminum is well realized. 3-hydroxyphenyl phosphoryl propionic acid has good water solubility and low cost, and the product after complexation reaction with metal ions is solid and easy to separate. It has potential as an alternative complexing agent in the industry.
      Citation: Minerals
      PubDate: 2022-06-10
      DOI: 10.3390/min12060743
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 744: Geological History of the Great Altai:
           Implications for Mineral Exploration

    • Authors: Boris A. D’yachkov, Marina A. Mizernaya, Sergey V. Khromykh, Ainel Y. Bissatova, Tatiana A. Oitseva, Anastassiya P. Miroshnikova, Olga V. Frolova, Oxana N. Kuzmina, Natalya A. Zimanovskaya, Anna P. Pyatkova, Karina Zikirova, Olga V. Ageyeva, Yertay T. Yeskaliyev
      First page: 744
      Abstract: The Great Altai region, located at the boundary of Russia, Mongolia, China, and Kazakhstan, belongs to the system of the Central Asian Orogenic Belt. It has undergone a long complex geological and metallogenic history. Extremely rich resources of base, precious, and rare metals (Fe, Cu, Pb, Zn, Ag, Au, Li, Cs, Ta, Nb, REE, etc.) maintain developed mining and metallurgical industry, especially in East Kazakhstan, which is the key metallogenic province. The East Kazakhstan province comprises the Rudny Altai, Kalba-Narym, West-Kalba, and Zharma-Saur metallogenic belts, each having its typical mineralization profiles and deposits. The reconstructed geodynamic and metallogenic history of the Great Altai province, along with the revealed relationships between tectonic settings and mineralization patterns, allowed us to formulate a number of geodynamic, structural, lithostratigraphic, magmatic, mineralogical, and geochemical criteria for exploration and appraisal of mineral potential in Eastern Kazakhstan. Geodynamic criteria are based on the origin of different mineralization types in certain geodynamic settings during the Late Paleozoic–Early Mesozoic orogenic cycle. Structural criteria mean that the location of base-metal deposits in Rudny Altai, gold deposits in the West Kalba belt, rare and base metals in the Kalba-Narym and Zharma-Saur zones is controlled by faults of different sizes. Lithostratigraphic criteria consist of the relation of orebodies with certain types of sedimentary or volcanic-sedimentary rocks. Magmatic criteria are due to the relation between mineralization types and igneous lithologies. Mineralogical and geochemical criteria include typical minerals and elements that can serve as tracers of mineralization. The joint use of all these criteria will open new avenues in prospecting and exploration at a more advanced level.
      Citation: Minerals
      PubDate: 2022-06-10
      DOI: 10.3390/min12060744
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 745: Knothe Time Function Optimization Model and
           Its Parameter Calculation Method and Precision Analysis

    • Authors: Qingfeng Hu, Ximin Cui, Wenkai Liu, Ruimin Feng, Tangjing Ma, Debao Yuan
      First page: 745
      Abstract: Considering the shortcomings of the currently used time functions for dynamically predicting surface mining subsidence and calculating its parameters, a novel time function is proposed on the basis of an in-depth analysis on the movement characteristics of mining surface points in a fully mined area and the measured mining subsidence data in the field during the course of the mining process. The proposed function can be used to effectively characterize the surface subsidence, the subsidence velocity, and the acceleration of the mining area. All the parameters involved in the function have their physical meaning, and their influence on the function was also analyzed in this study. A parameter calculation method is proposed for the new time function based on the normalization method and least square principle. Taking the measured dynamic subsidence data of 22,618 working faces in a coal mine as an example, the reliability of the new time function model was verified by comparing the measured data with the predicted results. The results show that the average relative root-mean-square error was 5.2%, and the prediction accuracy was improved compared with the Knothe time function, double-parameter Knothe time function, and piecewise optimized Knothe time function.
      Citation: Minerals
      PubDate: 2022-06-11
      DOI: 10.3390/min12060745
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 746: Analytical Approach Based on Full-Space
           Synergy Technology to Optimization Support Design of Deep Mining Roadway

    • Authors: Shike Zhang, Shunde Yin
      First page: 746
      Abstract: The stability of surrounding rock is the basic guarantee of underground space engineering safety. The large deformation of a roadway’s surrounding rock is a very common phenomenon during the underground excavation of coal mine roadways or coal mining, especially in deep soft rock mining roadways. With the increase in mining depth and mining stress, it is very important to prevent disasters caused by surrounding rock deformation. This work aims to conduct an optimization design of roadway support for deep soft rock in coal mines using a full-space synergy control technology. FLAC3D-based orthogonal numerical experiments are adopted to study the influence of bolt parameters and plastic yield zone variation on the deformation of roadway surrounding rock, which provides a basis for optimizing the support design of coal mine roadways. According to the results of the numerical analysis, the optimal support parameters are determined as 20 mm, 2.2 m and 700–900 mm for diameter, length and interval of the bolt, respectively. Finally, the determined bolt-shotcrete net beam support scheme from the full-space synergy control idea is used in a study case. Results illustrate that this study can provide reliable guidance for the stability control of deep soft rock roadways in mining fields under high stress, and it can work well to keep the surrounding rock deformation within the safe limits.
      Citation: Minerals
      PubDate: 2022-06-12
      DOI: 10.3390/min12060746
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 747: A Novel Method for Conducting a
           Geoenvironmental Assessment of Undiscovered ISR-Amenable Uranium
           Resources: Proof-of-Concept in the Texas Coastal Plain

    • Authors: Tanya J. Gallegos, Victoria G. Stengel, Katie Walton-Day, Johanna Blake, Andrew Teeple, Delbert Humberson, Steven Cahan, Douglas B. Yager, Kent D. Becher
      First page: 747
      Abstract: A geoenvironmental assessment methodology was developed to estimate waste quantities and disturbances that could be associated with the extraction of undiscovered uranium resources and identify areas on the landscape where uranium and other constituents of potential concern (COPCs) that may co-occur with uranium deposits in this region are likely to persist, if introduced into the environment. Prior to this work, a method was lacking to quantitively assess the environmental aspects associated with potential development of undiscovered uranium resources at a scale of a uranium resource assessment. The mining method of in situ recovery (ISR) was historically used to extract uranium from deposits in the Goliad Sand of the Texas Coastal Plain. For this reason, the study’s methodology projected the following types of wastes and disturbances commonly associated with ISR based on historical ISR mining records: the mine area, affected aquifer volume, mine pore volume, water pumped and disposed during uranium extraction and restoration, and radon emissions. Within the tract permissive for the occurrence of undiscovered uranium resources, maps and statistics of factors were derived that indicate the potential contaminant pathways. The percentage of days meeting the criteria for air stagnation indicate the potential for radon accumulation; the geochemical mobility of COPCs in groundwater in combination with effective recharge indicates the potential for infiltration of surface-derived COPCs; the geochemical mobility of COPCs in groundwater combined with hydraulic conductivity indicates the propensity for transmitting fluids away from contaminated or mined aquifers; and finally, geochemical mobility of COPCs in surface water combined with the factor for climatic erosivity (R factor) indicates the potential for COPCs to persist in surface waters due to runoff. This work resulted in a new methodology that can be applied to any undiscovered mineral resource to better understand possible wastes and disturbances associated with extraction and identify areas on the landscape where COPCs are likely to persist.
      Citation: Minerals
      PubDate: 2022-06-12
      DOI: 10.3390/min12060747
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 748: Selective Leaching of Valuable Metals from
           Spent Fluid Catalytic Cracking Catalyst with Oxalic Acid

    • Authors: Dalong Zheng, Yimin Zhang, Tao Liu, Jing Huang, Zhenlei Cai, Ruobing Zhang
      First page: 748
      Abstract: The problem of spent fluid catalytic cracking (SFCC) catalyst resource utilization, draws more and more attention to system analysis. SFCC was leached in an oxalic solution for comprehensive utilization. The results showed that for a D50 ≤ 17.34 μm, the catalyst leached for 240 min at 95 °C in the presence of a 2 mol/L oxalic acid solution, and the extent of leaching of V, Ni, Fe, and Al was 73.4%, 32.4%, 48.2%, and 36.8%, respectively. Studies on the occurrence state of the main ions (V, Ni, Fe, and Al) in the leaching solution were presented. Additionally, the separation of the main ions from such a solution by the “solvent extraction-stripping-hydrothermal precipitation-comprehensive recovery of valuable metal” process was studied. The immobilization rates of vanadium and nickel in geopolymers can be obtained using the toxicity characteristic leaching procedure (TCLP) test, and the geopolymers prepared by SFCC leaching residues can be considered a non-hazardous material. A process diagram of the comprehensive utilization of SFCC catalysts is presented.
      Citation: Minerals
      PubDate: 2022-06-13
      DOI: 10.3390/min12060748
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 749: An Efficient and Economical Combination of
           Exploration Methods for Pb-Zn Polymetallic Skarn Deposits: A Case Study of
           the Periphery of Hetaoping Deposit, Yunnan Province, China

    • Authors: Jingzi He, Tengfei Ge, Hongjie Tan, Xuzhao Huang, Shengqing Xiong, Zhengguo Fan, Dalong Dai
      First page: 749
      Abstract: The Hetaoping ore district in Baoshan City, Yunnan Province, is one of the major localities of Pb-Zn polymetallic skarn deposits in China, where geophysical and geochemical surveys play an important role in exploring Pb-Zn polymetallic mineral resources. Based on the exploration and prospecting carried out at the periphery of the Hetaoping Pb-Zn polymetallic deposit, this study proposed an aero-ground joint exploration method to determine the metallogenic model of distal skarns in the Hetaoping ore district, achieving ideal prospecting results. The steps of this method are as follows. First, the locations of ore-induced anomalies were determined using high-amplitude aeromagnetic anomalies. Then, the ore-induced anomalies were determined to be anomalies of Pb-Zn polymetallic deposits through geochemical surveys of soil samples and ground geophysical surveys. Based on these data, a quantitative analysis and metallogenic potential assessment of ore bodies and their surrounding rocks were conducted using the interactive 2.5D magnetic inversion. In addition, the 3D inversion of regional gravity data was also performed in order to determine the spatial location of the deep magma chamber. Accordingly, the metallogenic geological process in this area was analyzed by determining the spatial morphology of the deep magma chamber, and a prospecting model of the Pb-Zn polymetallic deposits was finally built. The results show that the aero-ground joint exploration method, which first conducts a rapid scanning survey using the aeromagnetic method and then locates, distinguishes, and assesses significant aeromagnetic anomalies by combining comprehensive verification means such as ground geophysical, geochemical, and geological surveys, is efficient and economical. This study will guide regional metallogenic research and the exploration and prospecting of Pb-Zn polymetallic deposits.
      Citation: Minerals
      PubDate: 2022-06-13
      DOI: 10.3390/min12060749
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 750: Accelerating Global Sensitivity Analysis via
           Supervised Machine Learning Tools: Case Studies for Mineral Processing

    • Authors: Freddy A. Lucay
      First page: 750
      Abstract: Global sensitivity analysis (GSA) is a fundamental tool for identifying input variables that determine the behavior of the mathematical models under uncertainty. Among the methods proposed to perform GSA, those based on the Sobol method are highlighted because of their versatility and robustness; however, applications using complex models are impractical owing to their significant processing time. This research proposes a methodology to accelerate GSA via surrogate models based on the modern design of experiments and supervised machine learning (SML) tools. Three case studies based on an SAG mill and cell bank are presented to illustrate the applicability of the proposed procedure. The first two consider batch training for SML tools included in the Python and R programming languages, and the third considers online sequential (OS) training for an extreme learning machine (ELM). The results reveal significant computational gains from the methodology proposed. In addition, GSA enables the quantification of the impact of critical input variables on metallurgical process performance, such as ore hardness, ore size, and superficial air velocity, which has only been reported in the literature from an experimental standpoint. Finally, GSA-OS-ELM opens the door to estimating online sensitivity indices for the equipment used in mineral processing.
      Citation: Minerals
      PubDate: 2022-06-14
      DOI: 10.3390/min12060750
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 751: Structural Controls on Mineralization within
           the Huanggou Gold Deposit in the Southern Mesozoic Xuefengshan Orogen,
           South China

    • Authors: Yuhua Xie, Hua Gao, Hua Kong, Han Zheng
      First page: 751
      Abstract: The Mesozoic Xuefengshan Orogen (XFSO) in South China hosts abundant gold ore deposits. The XFSO records a history of polyphase tectonic deformation and the structural controls on gold mineralization are poorly understood. The recently discovered quartz-vein type Huanggou gold deposit in the southern XFSO is characterized by multiple stages of deformation and represents an excellent natural laboratory for deciphering structural controls on gold mineralization in a complex orogenic belt. A systematic structural analysis indicates that the geometry of the Huanggou gold deposit and adjacent areas mainly resulted from four stages of deformation: (1) D1 top-to-the-NW sense of shearing; (2) D2 SE-directed back-folding and back-thrusting; (3) D3 NW–SE upright folding; and (4) D4 NW–SE normal faulting and fracturing. Two sets of quartz veins are exposed in the deposit: (1) SE-dipping Au-bearing quartz veins; and (2) NW-dipping non-mineralized quartz veins. The SE-dipping Au-bearing quartz veins were likely formed by the main deformation phase of the XFSO. During D1 top-to-the-NW simple shearing, these synkinematic Au-bearing quartz veins progressively evolved into sigmoidal shapes and rotated to a preferred SE-dipping orientation. Subsequently, D2 SE-directed back-folding and back-thrusting resulted in the formation of synkinematic NW-dipping non-mineralized quartz veins. D3 upright folding locally steepened the dips of both Au-bearing and non-mineralized quartz veins. Our results may provide new insights into the structural controls of gold mineralization in the XFSO.
      Citation: Minerals
      PubDate: 2022-06-14
      DOI: 10.3390/min12060751
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 752: Effects of Charged Solute-Solvent
           Interaction on Reservoir Temperature during Subsurface CO2 Injection

    • Authors: Christopher Paolini
      First page: 752
      Abstract: A short-term side-effect of CO2 injection is a developing low-pH front that forms ahead of the bulk water injectant, due to differences in solute diffusivity. Observations of downhole well temperature show a reduction in aqueous-phase temperature with the arrival of a low-pH front, followed by a gradual rise in temperature upon the arrival of a high concentration of bicarbonate ion. In this work, we model aqueous-phase transient heat advection and diffusion, with the volumetric energy generation rate computed from solute-solvent interaction using the Helgeson–Kirkham–Flowers (HKF) model, which is based on the Born Solvation model, for computing specific molar heat capacity and the enthalpy of charged electrolytes. A computed injectant water temperature profile is shown to agree with the actual bottom hole sampled temperature acquired from sensors. The modeling of aqueous-phase temperature during subsurface injection simulation is important for the accurate modeling of mineral dissolution and precipitation because forward dissolution rates are governed by a temperature-dependent Arrhenius model.
      Citation: Minerals
      PubDate: 2022-06-14
      DOI: 10.3390/min12060752
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 753: The Efficiency of Black Mass Preparation by
           Discharge and Alkaline Leaching for LIB Recycling

    • Authors: Tiaan Punt, Steven M. Bradshaw, Petrie van Wyk, Guven Akdogan
      First page: 753
      Abstract: Lithium-ion batteries (LIBs) are dangerous to recycle, as they pose a fire hazard when cut and contain various chemical hazards. If recycled safely, LIBs provide a rich secondary source for metals such as lithium and cobalt, while reducing the environmental impact of end-of-life LIBs. Discharging the spent LIBs in a 5 wt.% NaCl electrolyte at room temperature enables their safe dismantling. A sludge was observed to form during the LIB discharging, with a composition of 34.9 wt.% Fe, 35 wt.% O, 17.7 wt.% Al, 6.2 wt.% C, and 4.2 wt.% Na. The average electrolytic solution composition after the first discharge cycle contained only 12.6 mg/L Fe, 4.5 mg/L Li, 2.5 mg/L Mn, and trace amounts of Ni and Co. Separating the active cathode powder from the aluminum cathode with a 10 wt.% NaOH leach produced an aqueous filtrate with an Al metal purity of 99.7%. The leach composition consisted of 9558 mg/L Al, 13 mg/L Li, 8.7 mg/L Co, and trace amounts of Mn and Ni. The hydrometallurgical sample preparation processes in this study enables the production of a pure black mass with less than 0.05 wt.% Co, 0.2 wt.% Li, 0.02 wt.% Mn, and 0.02 wt.% Ni losses from the active cathode material.
      Citation: Minerals
      PubDate: 2022-06-14
      DOI: 10.3390/min12060753
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 754: Ground Stress Analysis and Automation of
           Workface in Continuous Mining Continuous Backfill Operation

    • Authors: Seun A. Ajayi, Liqiang Ma, Anthony J. S. Spearing
      First page: 754
      Abstract: The cost, complexity, lack of filling space and time create challenges in the longwall backfill operation, resulting in poor subsidence control and reduced productivity. This paper proposes an automated continuous mining and continuous backfill (CMCB) method by examining its key requirements and investigates the optimum sequence of coal panel (such as drifts) excavation to ensure ground strata control at relatively high productivity. The automated CMCB adopts the highwall mining technique underground, which enables easier automation at the workface. A numerical simulation of the Changxing coal mine in China was undertaken, and five different sequences of coal excavation were investigated, using the automated CMCB excavation parameters (assuming a 4 m width cut, 5 m mining height for a 200 m long coal slice) to determine the optimum sequence of resource excavation. The plastic zones and vertical displacement across the five models were analyzed. Simulation results of the 5 m high coal seam excavation show that the odd-even slice (OES) mining sequence, which has a vertical ground displacement of 74 mm, is the most efficient excavation method, due to its effective stress redistribution and lower induced ground displacement.
      Citation: Minerals
      PubDate: 2022-06-14
      DOI: 10.3390/min12060754
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 755: Assessment of Easily Accessible
           Spectroscopic Techniques Coupled with Multivariate Analysis for the
           Qualitative Characterization and Differentiation of Earth Pigments of
           Various Provenance

    • Authors: Ioana Maria Cortea, Luminița Ghervase, Roxana Rădvan, George Serițan
      First page: 755
      Abstract: Natural minerals and earths with coloring properties have been widely used as artistic pigments since prehistoric times. Despite being extensively studied, the complex chemistry of earth pigments is still unsatisfactory described with respect to their mineralogical and structural variability and origin. In this study, a large group of earth pigments from various geographical locations was investigated using easily accessible spectroscopic techniques and multivariate analysis with the aim to identify distinctive mineralogical and chemical characteristics of natural pigment sources. Portable X-ray fluorescence (p-XRF), Fourier transform infrared spectroscopy (FTIR) and fiberoptic Raman spectroscopy were used for the elemental, molecular and structural characterization of the investigated pigments. Diagnostic spectral features and chemical patterns (fingerprints) were identified and discussed with respect to their geological sources. Due to the occurrence of similar accompanying minerals, it was observed that the differentiation of red and yellow ochers is more challenging compared to green, brown and black pigments. However, for some of the investigated pigments, the presence of certain accessory minerals and/or of certain chemical patterns can have diagnostic value. Principal component analysis (PCA) of the FTIR and XRF data matrices showed promising results in terms of geological attribution, highlighting a promising tool for provenance research. The results of the study demonstrate the potential benefits of this rapid and nondestructive approach for the characterization and differentiation of earth pigments with similar hues coming from different geological sources.
      Citation: Minerals
      PubDate: 2022-06-14
      DOI: 10.3390/min12060755
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 756: Dissolution and Solubility of the
           Calcite–Otavite Solid Solutions [(Ca1−xCdx)CO3] at 25 °C

    • Authors: Chengyou Ma, Fan Xu, Zongqiang Zhu, Hongqu Yang, Peijie Nong, Zhiqiang Kang, Shen Tang, Lihao Zhang, Yinian Zhu
      First page: 756
      Abstract: A complete series of the calcite–otavite solid solutions [(Ca1−xCdx)CO3] were prepared, and their dissolution processes lasting nine months were experimentally investigated. For the dissolution in the N2-degassed water, the Ca concentrations of the aqueous phases increased up to the steady states after 5040 h of dissolution, and the Cd concentrations of the aqueous phases increased up to the highest values and then decreased gradually to the steady states of 0.017–6.476 μmol/L after 5040 h of dissolution. For the dissolution in the CO2-saturated water, the Ca and Cd concentrations of the aqueous phases increased up to the peak values and then decreased gradually to the steady states of 0.94–0.46 mmol/L and 0.046–9.643 μmol/L after 5040 h of dissolution, respectively. For the dissolution in the N2-degassed water at 25 °C, the mean solubility products (log Ksp) and the Gibbs free energies of formation (ΔGfθ) were estimated to be −8.45–−8.42 and −1129.65–−1129.48 kJ/mol for calcite [CaCO3] and −11.62–−11.79 and −671.81–−672.78 kJ/mol for otavite [CdCO3], respectively. Generally, the log Ksp values decreased non-linearly, and the ΔGfθ values increased linearly with the increasing Cd/(Ca+Cd) mole ratio (XCd) of the (Ca1−xCdx)CO3 solid solutions. In the Lippmann diagrams constructed for the sub-regular (Ca1−xCdx)CO3 solid solutions with the estimated Guggenheim coefficients a0 = −0.84 and a1 = −3.80 for the dissolution in the N2-degassed water or a0 = −1.12 and a1 = −3.83 for the dissolution in the CO2-saturated water, the (Ca1−xCdx)CO3 solid solutions dissolved incongruently, moved progressively up to the quasi-equilibrium curves for otavite and then along the quasi-equilibrium curve from right to left, approached the solutus curve and finally reached the minimum stoichiometric saturation curve for calcite. The considerably Cd-poor aqueous phases were finally in equilibrium with the CdCO3-rich solid phases.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060756
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 757: Metal Lability and Mass Transfer Response to
           Direct-Planting Phytostabilization of Pyritic Mine Tailings

    • Authors: Corin M. Hammond, Robert A. Root, Raina M. Maier, Jon Chorover
      First page: 757
      Abstract: Understanding the temporal effects of organic matter input and water influx on metal lability and translocation is critical to evaluate the success of the phytostabilization of metalliferous mine tailings. Trends of metal lability, e.g., V, Cr, Mn, Co, Ni, Cu, Zn, and Pb, were investigated for three years following a direct-planting phytostabilization trial at a Superfund mine tailings site in semi-arid central Arizona, USA. Unamended tailings were characterized by high concentrations (mmol kg−1) of Fe (2100), S (3100), As (41), Zn (39), and Pb (11), where As and Pb greatly exceeded non-residential soil remediation levels established by Arizona. Phytostabilization treatments included a no-compost control, 100 g kg−1 compost with seed, and 200 g kg−1 compost with and without seed to the top 20 cm of the tailings profile. All plots received supplemental irrigation, effectively doubling the mean annual precipitation. Tailings cores up to 90 cm were collected at the time of planting and every summer for 3 years. The cores were sub-sectioned at 20 cm increments and analyzed via total digestion and an operationally defined sequential extraction for elemental analysis and the calculation of a mass transfer coefficient normalized to Ti as an assigned immobile element. The results indicate that Pb was recalcitrant and relatively immobile in the tailings environment for both the uncomposted control and composted treatments with a maximum variation in the total concentration of 9–14 mmol kg−1 among all samples. Metal lability and translocation above the redox boundary (ca. 30 cm depth) was governed by acid generation, where surficial pH was measured as low as 2.7 ± 0.1 in year three and strongly correlated with the increased lability of Mn, Co, Ni, Cu, and Zn. There was no significant pH effect on the lability of V, Cr, or Pb. Translocation to depths was greatest for Mn and Co; however, Zn, Ni, Cr, and Cu were also mobilized. The addition of organic matter enhanced the mobilization of Cr from the near surface to 40–60 cm depth (pH > 6) over the three-year phytostabilization study compared to the control. The increased enrichment of some metals at 60–90 cm indicates that the long-term monitoring of elemental translocation is necessary to assess the efficacy of phytostabilization to contain subsurface metal contaminants and thereby protect the surrounding community from exposure.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060757
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 758: Tin and Bronze Production at the Outeiro de
           Baltar Hillfort (NW Iberia)

    • Authors: Elin Figueiredo, Alexandra Rodrigues, João Fonte, Emmanuelle Meunier, Filipa Dias, Alexandre Lima, José Alberto Gonçalves, Luís Gonçalves-Seco, Filipe Gonçalves, Manuel F. C. Pereira, Rui J. C. Silva, João P. Veiga
      First page: 758
      Abstract: Findings of Iron Age metallurgical activities related to tin metal and mining are very rare. In the present work, we present a detailed study of the Outeiro de Baltar hillfort, dated to the Late Iron Age/Early Roman period, located in a place where 20th century tin mining work took place. Elemental and microstructural analysis by portable, micro and wavelength dispersive X-ray fluorescence spectrometry (pXRF, micro-XRF and WDXRF) and scanning electron microscopy with energy dispersion spectrometer (SEM-EDS) showed that metallurgical debris found at the archaeological site is related to tin smelting and binary and ternary bronze productions. Analysis of the artefacts of diverse typologies found at the site showed that a variety of metals and alloys were in circulation and use. Samples of tin ores (cassiterite) from the region were analyzed for comparison with an archaeological tin slag from the site. The analytical results point to the production of tin metal using local cassiterite and the production of bronze by directly adding cassiterite into a smelting process. Furthermore, data of remote sensing (airborne Light Detection and Ranging (LiDAR) and historical aerial imagery) and Geographical Information System (GIS) mapping were combined with archival mining documentation and maps to retrieve a landscape context for the site. The study showed that the place of the Outeiro de Baltar hillfort (NW Iberia) was mined periodically over time.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060758
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 759: A Review of the Lunar 182Hf-182W Isotope
           System Research

    • Authors: Zhen Yang, Guiqin Wang, Yuming Xu, Yuling Zeng, Zhaofeng Zhang
      First page: 759
      Abstract: In recent years, the extinct nuclide 182Hf-182W system has been developed as an essential tool to date and trace the lunar origin and evolution. Despite a series of achievements, controversies and problems exist. As a review, this paper details the application principles of the 182Hf-182W isotope system and summarizes the research development on W isotopes of the Moon. A significant radiogenic ε182W excess of 0.24 ± 0.01 was found in the lunar mantle, leading to heated debates. There are three main explanations for the origin of the excess, including (1) radioactive origin; (2) the mantle of the Moon-forming impactor; and (3) disproportional late accretion to the Earth and the Moon. Debates on these explanations have revealed different views on lunar age. The reported ages of the Moon are mainly divided into two views: an early Moon (30–70 Ma after the solar system formation); and a late Moon (>70 Ma after the solar system formation). This paper discusses the possible effects on lunar 182W composition, including the Moon-forming impactor, late veneer, and Oceanus Procellarum-forming projectile. Finally, the unexpected isotopic similarities between the Earth and Moon are discussed.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060759
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 760: Modeling of Brine/CO2/Mineral Wettability
           Using Gene Expression Programming (GEP): Application to Carbon

    • Authors: Jafar Abdi, Menad Nait Amar, Masoud Hadipoor, Thomas Gentzis, Abdolhossein Hemmati-Sarapardeh, Mehdi Ostadhassan
      First page: 760
      Abstract: Carbon geo-sequestration (CGS), as a well-known procedure, is employed to reduce/store greenhouse gases. Wettability behavior is one of the important parameters in the geological CO2 sequestration process. Few models have been reported for characterizing the contact angle of the brine/CO2/mineral system at different environmental conditions. In this study, a smart machine learning model, namely Gene Expression Programming (GEP), was implemented to model the wettability behavior in a ternary system of CO2, brine, and mineral under different operating conditions, including salinity, pressure, and temperature. The presented models provided an accurate estimation for the receding, static, and advancing contact angles of brine/CO2 on various minerals, such as calcite, feldspar, mica, and quartz. A total of 630 experimental data points were utilized for establishing the correlations. Both statistical evaluation and graphical analyses were performed to show the reliability and performance of the developed models. The results showed that the implemented GEP model accurately predicted the wettability behavior under various operating conditions and a few data points were detected as probably doubtful. The average absolute percent relative error (AAPRE) of the models proposed for calcite, feldspar, mica, and quartz were obtained as 5.66%, 1.56%, 14.44%, and 13.93%, respectively, which confirm the accurate performance of the GEP algorithm. Finally, the investigation of sensitivity analysis indicated that salinity and pressure had the utmost influence on contact angles of brine/CO2 on a range of different minerals. In addition, the effect of the accurate estimation of wettability on CO2 column height for CO2 sequestration was illustrated. According to the impact of wettability on the residual and structural trapping mechanisms during the geo-sequestration of the carbon process, the outcomes of the GEP model can be beneficial for the precise prediction of the capacity of these mechanisms.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060760
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 761: Genetic Association between Granites and
           Mineralization at the Gindi Akwati Cassiterite–Sulfide Deposit,
           North-Central Nigeria: Insights from Mineralogy, Fluid Inclusions, and
           Sulfur Isotopes

    • Authors: Abdulgafar Kayode Amuda, Shuang Li, Xiaoyong Yang, Jingya Cao, Mohamed Faisal
      First page: 761
      Abstract: The cassiterite–sulfide mineralization occurs within quartz veins and greisenized Precambrian Older Granite around the Gindi Akwati region at the Ropp complex’s western boundary, north-central Nigeria. The intrusion of Jurassic Younger granite porphyry sheared the marginal parts of the Older Granite and the mylonitized zone created pathways for fluids that escaped during the late-stage consolidation of Jurassic biotite granite. The biotite granites are highly differentiated (K/Rb < 200), peraluminous (A/CNK > 1), high-K, and have high Sn concentrations (average = 117 ppm). The intrusion of Jurassic granite porphyry forced Older Granite interaction with ore-bearing fluid that escaped from Jurassic biotite granite under low oxygen fugacity at or below the NNO buffer. The above fluid–rock interaction caused mass changes in host granite during greisenization and redistributed ores in the vicinity of the shears. This suggests that chloride ions take the form of significant complex-forming ligands and efficiently sequestrate, transport, and deposit ore metals (Sn, Zn, Fe, and Cu) locally within the greisenized granites and quartz veins. The redox potential of the ores probably gave a false impression of metal zoning with a relatively higher abundance of the oxide ore than the sulfides at the surface. The alteration mineralogy (quartz-, topaz-, lepidolite-, and fluorite-bearing assemblages) coupled with S isotope and fluid inclusion systematic data suggests the hydrothermal history of “greisens” and veins started with hot (homogenization temperature ≥300 °C), low to moderate salinity (average = 4.08 wt. % NaCl), low density (≤0.6 g/cm3) fluids and ≥ 200 bar trapping pressure. The sulfide isotopic composition (δ34SV-CDT = −1.30 to + 0.87 ‰) is very similar to typical magmatic fluids, indicating late-magmatic to early post-magmatic models of mineralization related to the anorogenic granite intrusions.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060761
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 762: Magmatic Processes of the Upper Cretaceous
           Susuma–Nagaho Plutonic Complex, Southwest Japan: Its Role on Crustal
           Growth and Recycling in Active Continental Margins

    • Authors: Shogo Kodama, Masaaki Owada, Mariko Nagashima, Atsushi Kamei
      First page: 762
      Abstract: Magmatic processes in the active continental margins are one of the important issues to understand the evolution of the continental crust. The Cretaceous Susuma–Nagaho plutonic complex, southwest Japan, is situated at the continental arc, and made up of gabbro, quartz diorite to granodiorite, and granite. According to the field occurrence, they are coeval intrusive rocks, and the biotite K–Ar ages of the granodiorite and granite are approximately 93 Ma, corresponding to the period of a magmatic flare-up in southwest Japan. Based on the whole-rock chemical analyses including Sr–Nd isotopic compositions, the granodiorite magma has been formed through fractional crystallization of basaltic magmas, whereas the origin of granite magma involved partial melting of the continental crust. The gabbro contains calcium-rich plagioclase (An > 90) and the presence of early crystallized hornblende, indicating its derivation from a hydrous basaltic magma. Such basaltic magma intruded into the middle to lower crust and supplied the heat energy necessary for crustal partial melting and granitic magma formation. The fractional crystallization and crustal melting took place at the same time, playing an important role in the crustal growth and differentiation during the magmatic flare-up event.
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060762
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 763: Expansion Properties of Cemented Foam
           Backfill Utilizing Coal Gangue and Fly Ash

    • Authors: Xiao Wang, Jixiong Zhang, Meng Li, Feng Gao, Abbas Taheri, Binbin Huo, Ling Jin
      First page: 763
      Abstract: The cemented backfill (CB) utilizing coal gangue (CG) and fly ash (FA) is widely applied in coal mines. However, the bleeding and shrinkage of CB leads to insufficient contact with surrounding rock, which is not beneficial for controlling roof subsidence and even stope stability. Herein, a cemented foam backfill (CFB) formulation is demonstrated, employing hydrogen dioxide (H2O2) as a chemical foaming agent. The cement and FA show noticeable inhibiting effects on volume expansion due to the network formed by their hydrates. Moderately lower cement, FA, and solid concentration are beneficial to improve volume increment and prolong expanding duration. A foaming coefficient (k) is proposed in theory to evaluate the foaming efficiency. The kem values, determined by volume evolution experiments of CFB slurries, provide a calculation basis for the needed dosage of H2O2 solution targeting specific volume increment. CFB specimens with expanding ratios of 21%~103% and densities of 994~592 kg/cm3 were prepared, with an actual foaming coefficient of 52.40 cm3/g and uniaxial compressive strength (UCS) of 0.32~0.55 MPa. The mass of H2O2 solution was 1.9%~11.3% of cement and 0.29%~1.67% of total solid materials by weight. The UCS decline compared to CB was attributed to rich pores observed by CT and carbonation indicated by X-ray diffraction (XRD).
      Citation: Minerals
      PubDate: 2022-06-15
      DOI: 10.3390/min12060763
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 764: Structural and Surface Modification of
           Oxalic-Acid-Activated Bentonites in Various Acid Concentrations for
           Bleaching Earth Synthesis—A Comparative Study

    • Authors: Danai Tsakiri, Iliana Douni, Maria Taxiarchou
      First page: 764
      Abstract: The aim of this study is to investigate the oxalic acid activation of bentonites containing different types of smectites, analyse their surface modification as a function of acid concentration and create good quality bleaching earths. In particular, two different bentonite samples (one containing aluminum and one containing ferruginous smectite), after being characterized through XRD, XRF and FT-IR analysis, are treated with oxalic acid at a concentration of 0.5, 0.7 and 1 M. Their structural modifications after treatment are observed through FT-IR spectra and surface area and porosity measurement (using the BET equation and the BJH method, respectively) combined with the determination of the main structural metals’ extraction from them (using an atomic adsorption spectrometer). The results showed that the ferruginous smectite is more susceptible to oxalic acid activation compared to the aluminum smectite, and all the final products have developed extra porosity in their structure while retaining the structure of smectite (even at 0.5 M acid concentration). The activated samples were used as bleaching earths in soybean oil, and the results proved that Lovibond yellow and red colours as well as the chlorophyll of oil (measured spectrophotometrically) were reduced to the values set by the specifications.
      Citation: Minerals
      PubDate: 2022-06-16
      DOI: 10.3390/min12060764
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 765: The Gold–Palladium Ozernoe Occurrence
           (Polar Urals, Russia): Mineralogy, Conditions of Formation, Sources of Ore
           Matter and Fluid

    • Authors: Valery Murzin, Galina Palyanova, Татiana Mayorova, Tatiana Beliaeva
      First page: 765
      Abstract: We studied the mineralization and sulfur isotopic composition of sulfides of gold–palladium ores in olivine clinopyroxenites from the Dzelyatyshor massif made up of a continuous layered series of rocks: olivine-free clinopyroxenite–olivine clinopyroxenite–wehrlite. The primary igneous layering of rocks, manifested as different quantitative ratios of clinopyroxene and olivine in them, controls the local trends of variability in the chemistry of mineral-forming medium and the concentrations of ore components, including noble metals, and sulfur in each separate layer during its cooling. The replacement of primary rock-forming minerals by secondary minerals, when the temperature decreases, is a characteristic trend for pyroxenites: (a) olivine → serpentine, secondary magnetite, and (b) clinopyroxene → amphibole, secondary magnetite → chlorite. The deposition of native gold in parageneses with PGM and sulfides at the Ozernoe occurrence took place during the replacement of earlier rock-forming minerals by chlorite. This process completed mineral formation at the deposit and took place at temperatures 150–250 °С and at the high activity of S, Te, Sb, and As of fluid. The variability of mineral formation conditions during chloritization is reflected in the change of native-sulfide forms of Pd by arsenide-antimonide forms and the sulfur isotopic composition of sulfides. The Pd content in native gold increases in the series—Au-Ag solid solution (<1.5 wt.% Pd)—Au-Cu intermetallides (to 6 wt.% Pd)—Cu-Au-Pd solid solutions (16.2–16.9 wt.% Pd). The sulfur isotopic composition of pyrite, chalcopyrite, and bornite varies from −2.1 to −2.9‰. It is assumed that a deep-seated magmatic basic melt was the source of fluid, ore components, and sulfur.
      Citation: Minerals
      PubDate: 2022-06-16
      DOI: 10.3390/min12060765
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 766: Identification and Suppression of
           Magnetotelluric Noise via a Deep Residual Network

    • Authors: Liang Zhang, Zhengyong Ren, Xiao Xiao, Jintian Tang, Guang Li
      First page: 766
      Abstract: The magnetotelluric (MT) method is widely applied in petroleum, mining, and deep Earth structure exploration but suffers from cultural noise. This noise will distort apparent resistivity and phase, leading to false geological interpretation. Therefore, denoising is indispensable for MT signal processing. The sparse representation method acts as a critical role in MT denoising. However, this method depends on the sparse assumption leading to inadequate denoising results in some cases. We propose an alternative MT denoising approach, which can achieve accurate denoising without assumptions on datasets. We first design a residual network (ResNet), which has an excellent fitting ability owing to its deep architecture. In addition, the ResNet network contains skip-connection blocks to guarantee the robustness of network degradation. As for the number of training, validation, and test datasets, we use 10,000,000; 10,000; and 100 field data, respectively, and apply the gradual shrinkage learning rate to ensure the ResNet’s generalization. In the noise identification stage, we use a small-time window to scan the MT time series, after which the gramian angular field (GAF) is applied to help identify noise and divide the MT time series into noise-free and noise data. We keep the noise-free data section in the denoising stage, and the noise data section is fed into our network. In our experiments, we test the performances of different time window sizes for noise identification and suppression and record corresponding time consumption. Then, we compare our approach with sparse representation methods. Testing results show that our approach can obtain the desired denoising results. The accuracy and loss curves show that our approach can well suppress the MT noise, and our network has a good generalization. To further validate our approach’s effectiveness, we show the apparent resistivity, phase, and polarization direction of test datasets. Our approach can adjust the distortion of apparent resistivity and phase and randomize the polarization direction distribution. Although our approach requires the high quality of the training dataset, it achieves accurate MT denoising after training and can be meaningful in cases of a severe MT noisy environment.
      Citation: Minerals
      PubDate: 2022-06-16
      DOI: 10.3390/min12060766
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 767: The Effect of Zn Content and Granulation
           Temperature on Zn Leaching in an Fe-Saturated (FeXZn(1−X))2SiO4

    • Authors: Jakob Kero Andertun, Pasi Peltola, Fredrik Engström, Caisa Samuelsson
      First page: 767
      Abstract: The zinc in the fayalite slag of copper smelters, in which Zn-containing raw materials are used, is mainly found to be in oxidic phases, such as glassy iron silicate. During the slag water granulation process, the molten slag is heated, whereby the granulated slag achieves varying granulation temperatures. Therefore, in this study, we aimed to characterize and assess the leaching behavior of a synthesized Fe-saturated (FeX,Zn(1−X))2SiO4 system to understand the dependance of the zinc leaching behavior on the parameters of the ZnO content (1–10 wt.%) and granulation temperature (1300 or 1400 °C). It was found that the Zn leaching increased with the increasing Zn content and granulation temperature, using both batch and static pH leaching methods. Zn leaching was further increased at pH 5 using diluted nitric acid under oxidation conditions. Among the oxides in the samples—fayalite, spinel, and glass—glass was found to contribute to Zn leaching, owing to its weathering during pH-titration.
      Citation: Minerals
      PubDate: 2022-06-16
      DOI: 10.3390/min12060767
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 768: The Southwestern Boundary of Cenozoic Qaidam
           Basin: Constraints from Heavy Mineral Analysis

    • Authors: Xiaonan Ding, Ling Fu, Ping Guan, Daowei Zhang
      First page: 768
      Abstract: The formation of the Qaidam Basin plays an important role in unraveling the growth history of the Tibetan plateau. An extraordinary thick Cenozoic sedimentary succession of the Qaidam Basin is a great contributor to the study of the basin’s evolution history. To date, there has been disagreement on the southwestern boundary of the Paleogene Qaidam Basin. In this study, the method of heavy mineral analysis was adopted to reconstruct the southwestern boundary of the Qaidam Basin. The stable heavy minerals which represent the maturity of detrital sediments can roughly reflect the distance between the source and the deposit area. Therefore, the isogram of the stable heavy mineral index (ZTR = 20) was compiled to infer the location of the source area of the southwestern Qaidam Basin. The isogram shows that the boundary of the southwestern Qaidam Basin stretched southwesterly to the present-day Qiman Tagh Eastern Kunlun Mountains during the Paleogene. Additionally, the isolines present a remarkable northward migration since the late Eocene, which indicates the boundary of the Cenozoic Qaidam Basin that withdrew northward since the late Eocene. The specific location of the southern source area of the Qaidam Basin can be deduced at the Adatan fault, the middle of the present-day Eastern Kunlun Mountains. This result also supports the idea that the Qaidam Basin was an independent basin during the early Cenozoic era, and the Eastern Kunlun Mountains have already been exhumed during that time, serving as a prominent source of clastic sediments in the southwestern Qaidam Basin.
      Citation: Minerals
      PubDate: 2022-06-16
      DOI: 10.3390/min12060768
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 769: 3D Multi-Parameter Geological Modeling and
           Knowledge Findings for Mo Oxide Orebodies in the Shangfanggou
           Porphyry–Skarn Mo (–Fe) Deposit, Henan Province, China

    • Authors: Zhifei Liu, Ling Zuo, Senmin Xu, Yaqing He, Chunyi Wang, Luofeng Wang, Tao Yang, Gongwen Wang, Linggao Zeng, Nini Mou, Wangdong Yang
      First page: 769
      Abstract: The Shangfanggou Mo–Fe deposit is a typical and giant porphyry–skarn deposit located in the East Qinling–Dabie molybdenum (Mo) polymetallic metallogenic belt in the southern margin of the North China Block. In this paper, three-dimensional (3D) multi-parameter geological modeling and microanalysis are used to discuss the mineralization and oxidation transformation process of molybdenite during the supergene stage. Meanwhile, from macro to micro, the temporal–spatial–genetic correlation and exploration constraints are also established by 3D geological modeling of industrial Mo orebodies and Mo oxide orebodies. SEM-EDS and EPMA-aided analyses indicate the oxidation products of molybdenite are dominated by tungsten–powellite at the supergene stage. Thus, a series of oxidation processes from molybdenite to tungsten–powellite are obtained after the precipitation of molybdenite; eventually, a special genetic model of the Shangfanggou high oxidation rate Mo deposit is formed. Oxygen fugacity reduction and an acid environment play an important part in the precipitation of molybdenite: (1) During the oxidation process, molybdenite is first oxidized to a MoO2·SO4 complex ion and then reacts with a carbonate solution to precipitate powethite, in which W and Mo elements can be substituted by complete isomorphism, forming a unique secondary oxide orebody dominated by tungsten–powellite. (2) Under hydrothermal action, Mo4+ can be oxidized to jordisite in the strong acid reduction environment at low temperature and room temperature during the hydrothermal mineralization stage. Ilsemannite is the oxidation product, which can be further oxidized to molybdite.
      Citation: Minerals
      PubDate: 2022-06-17
      DOI: 10.3390/min12060769
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 770: Research on Uniaxial Compression Mechanics
           of Diorite under Flowing Acidic Solution Scouring

    • Authors: Wei Chen, Li Wu, Zhi Zeng, Wen Wan, Jie Liu, Xiaofan Wu, Wenqing Peng, Xiantao Zeng, Zhenhua Ren, Senlin Xie, Yu Zhou
      First page: 770
      Abstract: The bedrock used for underground construction has obvious traces of hydrodynamic scouring damage, and the mechanical properties of bedrock especially are severely damaged under a groundwater environment. On this basis, considering the excavated bedrock under various saturations, the uniaxial compression test of diorite is carried out. Meanwhile, scanning electron microscopy (SEM), electron energy spectroscopy (EDS) and X-ray diffraction (XRD) are used in the experiment. The variation law of the elastic p-wave velocity and microstructure and the response characteristics of the strength, deformation and mechanical parameters of rock under different flow rates and pH values are analyzed in detail. The results indicate that: (1) Saturations with a faster flow rate and lower pH value cause greater relative changes in the elastic longitudinal wave velocity of the samples. (2) The uniaxial compressive strength of the samples under various treatment conditions showed a decreasing trend. Compared with the dried samples, the uniaxial compressive strength of the samples under saturation with field flow rate v = 300 mm·s−1 and pH = 1 decreased by 46.08%, and the strength decreased by 35.67% under saturation with a field pH value = 6.56 and flow rate v = 900 mm-s−1. (3) The saturation with a stronger acidity, greater flow rate and longer action time causes the apparent dense structure of the diorite sample to be loose and accompanied by microcracks, which weakens its macromechanical properties. (4) Acid and hydrodynamic saturation produce water–rock chemical and physical effects on diorite, which weaken the connection force between mineral particles and the friction between fracture surfaces, reduce the elastic modulus, increase Poisson’s ratio and accelerate the failure of diorite.
      Citation: Minerals
      PubDate: 2022-06-17
      DOI: 10.3390/min12060770
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 771: Petrogenesis and Geological Significance of
           the Quartz Monzonites in the Jinling Area, Western Shandong Province

    • Authors: Zhao-Lu Zhang, Chao Zhang, Ye Li, Lu-Yuan Wang, Ji-Lei Gao, Ming Ma, Ya-Dong Li
      First page: 771
      Abstract: Jinling complex pluton is a key part of the Mesozoic magmatic belt in the eastern North China Craton. However, its petrogenesis is still being debated. The Jinling complex, mainly composed of biotite diorites, hornblende diorite, augite diorites, (quartz) monzonites, and quartz diorites, is outcropped in Huashan and Heitieshan. This paper studies the zircon geochronology, zircon Hf isotope, and Sr-Nd-Pb isotope of quartz monzonites. The samples have high contents of Cr, Ni, V, Al2O3, Ba, Sr, and are enriched in LREEs, LILEs (K, Ba, Sr), depleted in HREEs, and HFSEs (Nb, Ta, Ti). The samples with captured zircons of ~2.5Ga yield a weighted mean age of ~127 Ma, and the zircons have negative values of εHf (t) from −3.2 to −9.4 while the ratios of 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb 37.75 ~ 38.15, 15.41 ~ 15.43, 17.59 ~ 17.98, respectively. The ratios of Th/U are from 3.77 to 3.82, while the values of μ and ω are 9.18 and from 35.72 to 36.15. Meanwhile, the ratios of 87Sr/86Sr are higher than the ones of the mantle. Geochemical and isotopic features indicate that the quartz monzonites derived from the subcontinental lithospheric mantle that probably assimilated ancient NCC upper crust materials (~15–20%) during the magma ascent in a lithospheric extension setting.
      Citation: Minerals
      PubDate: 2022-06-17
      DOI: 10.3390/min12060771
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 772: Bentonite Powder XRD Quantitative Analysis
           Using Rietveld Refinement: Revisiting and Updating Bulk Semiquantitative
           Mineralogical Compositions

    • Authors: Jaime Cuevas, Miguel Ángel Cabrera, Carlos Fernández, Carlos Mota-Heredia, Raúl Fernández, Elena Torres, María Jesús Turrero, Ana Isabel Ruiz
      First page: 772
      Abstract: Bentonite is a claystone formed by a complex mineralogical mixture, composed of montmorillonite, illite, and accessory minerals like quartz, cristobalite, feldspars, carbonates, and minor amounts of iron oxy-hydroxides. Bentonite presents complexity at various scales: (1): a single mineral may present different chemical composition within the same quarry (e.g., feldspars solid solutions); (2): montmorillonite presents variability in the cation-exchange distribution while illite may be presented as mixed-layer with smectite sheets; and (3): hardness and crystal size are larger in accessory minerals than in clay minerals, preventing uniform grinding of bentonite. The FEBEX bentonite used is originally from Almería (Spain), and it is a predominantly calcium, magnesium, and sodium bentonite. This Spanish FEBEX bentonite has been hydrothermally altered at laboratory scale for 7–14 years. A thermal gradient was generated by heating a disk of pressed iron powder, simulating the metal waste canister, in contact with the compacted bentonite sample. Hydration was forced from the opposite direction. XRD recorded patterns were very similar. In order to minimize the bias of XRD semi-quantitative determination methods, Rietveld refinement was performed using BGMN software and different structural models. Confidence in the quantification of the main phases allows us to convincingly detect other subtle changes such as the presence of calcite in the hydration front, right at the interface between the saturated and unsaturated bentonite, or the presence of goethite, and not hematite, in the saturated bentonite, near the source of hydration. Smectite component was 72 ± 3% and the refinement was consistent with the presence of ~10% illite, comparable with previous characterizations.
      Citation: Minerals
      PubDate: 2022-06-17
      DOI: 10.3390/min12060772
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 773: Influence of Clogging at the Filtration on
           Analysis of Dissolved and Particulate Forms of Chemical Elements in Boreal
           Rivers of the Russian Far East

    • Authors: Vladimir Shulkin, Natalia Bogdanova, Evgeniy Elovskiy
      First page: 773
      Abstract: Clogging is inevitable when membranes with 0.45 µm pore size are used for the separation of particulates from dissolved/colloidal forms in river water. This can lead to a shift in water quality assessment and evaluation of geochemical fluxes. We studied the influence of clogging on the concentration of trace elements, major anions, nitrate, and dissolved organic carbon (DOC) in the filtrates after a sequential pass from 0.1 to 0.5 L of river water samples through the same 47 mm membrane with 0.45 µm pore size. These experiments were carried out for the typical boreal rivers of the Russian Far East, including the biggest one, Amur R., with different quantities of suspended solids (SS) and anthropogenic load. The concentration of the major anions, nitrate, Si, DOC, and such trace elements as Li, B, Ni, Cu, As, Sr, Rb, Mo, Ba, U did not depend on the water volume filtered. However, filterable Al, Fe, Ti, Pb, Mn, Co, and most REEs showed a notable decrease in concentration at an increase in volume filtered, at more than 100–200 mL of river water. Clogging membranes with retention of colloids <0.45 µm was suggested as a reason for such a decrease. The quantity of suspended solids and their grain size are the major factors that control clogging itself. Still, the influence of clogging on the concentration of filterable forms depends on the share of coarse colloidal forms. Moreover, retention of colloids <0.45 µm by the clogged membrane can bias the assessment of particulate forms. Surpluses of particulate Fe, Al, Mn, Co due to clogging decline from 13–26% to 2–6% of suspended forms of these metals at the growth of SS in river waters from 10 mg/L to more than 50 mg/L. For particulate REEs, the share due to membrane clogging varies non-linearly from 2–9% to 23–39%, depending on the initial concentration of filterable forms of REEs in the river waters.
      Citation: Minerals
      PubDate: 2022-06-17
      DOI: 10.3390/min12060773
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 774: Differences in Properties between Pebbles
           and Raw Ore from a SAG Mill at a Zinc, Tin-Bearing Mine

    • Authors: Wenhan Sun, Jinlin Yang, Hengjun Li, Wengang Liu, Shaojian Ma
      First page: 774
      Abstract: Semi-autogenous (SAG) mills are widely used grinding equipment, but some ore with critical particle sizes cannot be effectively processed by SAG mills and turned into pebbles. This research aims to analyze and compare the properties of raw ore and pebbles from a zinc- and tin-bearing ore. The results show that the contents of sphalerite, cassiterite, biotite, antigorite, pyroxferroite, ferroactinolite, and ilvaite in the raw ore are higher than those in the pebbles, and that the pebbles have higher contents of hedenbergite, chlorite, epidote, actinolite, etc. Meanwhile, the abrasion and impact resistance of pebbles is greater than that of the raw ore. In addition, the sphalerite is evenly embedded, and the grinding process is regular. Fine cassiterite associated with harder minerals is difficult to dissociate; it is often found in softer or brittle minerals which may be easily ground into ore mud. The cassiterite in the pebbles is associated with hard and brittle hedenbergite and soft chlorite, making it difficult to recover. This research provides a good foundation for evaluating the recovery value of pebbles and improving the productivity of the SAG process.
      Citation: Minerals
      PubDate: 2022-06-17
      DOI: 10.3390/min12060774
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 775: The Hidden Magmatic Chamber from the Ponte
           Nova Mafic–Ultramafic Alkaline Massif, SE Brazil: Clues from
           Clinopyroxene and Olivine Antecrysts

    • Authors: Rogério Guitarrari Azzone, Lina Maria Cetina Tarazona, Mariana Robertti Ambrosio, Vincenza Guarino, Luanna Chmyz, Nicholas Machado Lima, Excelso Ruberti
      First page: 775
      Abstract: Clinopyroxene and olivine primocrysts in the intrusions of the Ponte Nova mafic–ultramafic alkaline massif (SE Brazil) present several textures and zoning that indicate open-system processes. Important compositional differences were found in the clinopyroxene. Diopside relict cores (mostly partially corroded) present higher Mg, Cr and Ni and lower Ti, Na, Al, REE and Sr than Ti-augite mantling and rims. Subordinately, two types of olivine crystals were recognized, one related to very zoned crystals with high Mg (Fo up to 86 mol.%) and Ni cores (mostly with corroded rims), and other almost without clear zonation and with lower Mg contents. Relict cores of high-Mg clinopyroxene and olivine crystals are representative of antecrysts formed in deeper chamber environments. Temperature and pressure estimates based on clinopyroxene-liquid geothermobarometers indicate crystallization of the antecrysts at ~1171 ± 10 °C and ~5.7 ± 0.3 kbar, pointing to a deeper hidden magmatic chamber, whereas mantling and rim compositions indicate a shallow chamber environment. Clinopyroxenes of this hidden chamber have progressive enrichments of incompatible elements with the Mg# decrement and inflection points in Sr and REE due to the starting of co-precipitation of apatite. The evolution trend of clinopyroxene antecrysts indicates that the main intrusions in the Ponte Nova shallow chamber were fed by a single deeper hidden chamber mainly controlled by typical fractional crystallization processes. These antecrysts indicate the presence of a complex plumbing system, which is also supported by similar antecrysts found in the lamprophyre and alkali basalt dikes of this region. The preferred petrological model for the Ponte Nova massif could be summarized as repeated influxes of antecryst-laden basanite magmas that deposited most of their suspended crystals on the floor of the upper-crust magma chamber.
      Citation: Minerals
      PubDate: 2022-06-18
      DOI: 10.3390/min12060775
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 776: Verification and Application of Sequence
           Stratigraphy to Reservoir Characterization of Horn River Basin, Canada

    • Authors: Juhwan Woo, Jiyoung Choi, Seok Hoon Yoon, Chul Woo Rhee
      First page: 776
      Abstract: Shale reservoirs, the most important unconventional resource, are difficult to characterize. Shale formations require detailed interpretation of geological, petrophysical, and geochemical analyses, and an integration of these disciplines. In terms of geological interpretation, the commonly used sequence stratigraphy analysis includes a lithofacies analysis. The application of sequence stratigraphy to shales facilitates the ability to relate between lithofacies and mineral composition, petrophysical parameters, and kerogen contents, which are affected by depositional setting. The classification of lithofacies is indispensable for reservoir quality prediction. In this study, porosity, permeability, and TOC content largely depend on lithofacies, and their correlation coefficient is relatively high. The sequence stratigraphic interpretation shows that organic carbon content usually increases within the maximum flooding surfaces and decreases stepwise. However, the relationship between total organic carbon contents and systems tract is less direct and redox dependent.
      Citation: Minerals
      PubDate: 2022-06-18
      DOI: 10.3390/min12060776
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 777: Searching Mass-Balance Analysis to Find the
           Composition of Martian Blueberries

    • Authors: Rif Miles Olsen
      First page: 777
      Abstract: Between 2004 and 2018, NASA’s rover Opportunity found huge numbers of small, hematite-rich spherules (commonly called blueberries) on the Meridiani Planum of Mars. The standard oxide composition distributions of blueberries have remained poorly constrained, with previous published analyses leaving hematite content somewhere in the broad range of 24–100 wt%. A searching mass-balance analysis is introduced and applied to constrain possible standard oxide composition distributions of blueberries consistent with the non-detection of silicates in blueberries by Opportunity’s instruments. This analysis found three groups of complete solution sets among the mass-balance ions consistent with the non-detection of silicates; although, a simple extension of the analysis indicates that one larger space of solutions incorporates all three groups of solutions. Enforcing consistency with the non-detection of silicates in blueberries constrains the hematite content in most of blueberry samples to between 79.5 and 99.85 wt%. A feature of the largest group of complete solution sets is that five oxides/elements, MgO, P2O5, Na2O, SO3, and Cl, collectively have a summed weight percentage that averages close to 6 wt%, while the weight percentage of nickel is close to 0.3 wt% in all solutions. Searches over multidimensional spaces of filtering composition distributions of basaltic and dusty soils were a methodological advance.
      Citation: Minerals
      PubDate: 2022-06-18
      DOI: 10.3390/min12060777
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 778: Experimental Investigation of Visible-Light
           and X-ray Emissions during Rock and Mineral Fracture: Role of Electrons
           Traveling between Fracture Surfaces

    • Authors: Toshihiko Kadono, Kazunori Ogawa, Kei Shirai, Masahiko Arakawa, Kosuke Kurosawa, Takaya Okamoto, Takafumi Matsui, Sunao Hasegawa, Ayako I. Suzuki, Hideyuki Kobayashi
      First page: 778
      Abstract: Radiation phenomena are usually observed during fracture of quartz-bearing rocks. Since quartz is a piezoelectric material, the associated electrical processes such as the electrification of fracture surface and the flight of electrons between fracture surfaces should be important for radiation during fractures. In this article, supposing that travelling electrons between crack surfaces cause the radiation, we experimentally investigate X-ray emission in a vacuum and visible-light emission in the atmosphere during rock and mineral fracture and verify the consistency of both emissions. The number of electrons in flight between surfaces during fracture that result in X-ray is estimated and the comparison with the number of photons in visible light suggests that one electron repeatedly collides with N2 molecules. The estimated number of collisions resulting in a visible-light emission is slightly less than the expected upper limit. This is reasonable because the collision would cause the light emission not always in the wavelengths of visible light. Moreover, the number of electrons resulting in X-rays is comparable with the number of electrons resulting in the emission of radio waves during fracture obtained in previous studies. Thus, we conclude that the radiations during fracture can be attributed to the flight of electrons between fracture surfaces. Finally, we evaluate the feasibility of observing the X-ray emission in planetary exploration and the radio waves and the visible light in natural earthquakes and find that these radiations are observable.
      Citation: Minerals
      PubDate: 2022-06-18
      DOI: 10.3390/min12060778
      Issue No: Vol. 12, No. 6 (2022)
  • Minerals, Vol. 12, Pages 779: CO2-Enhanced Oil Recovery Mechanism in
           Canadian Bakken Shale

    • Authors: Majid Bizhani, Omid Haeri Ardakani, Steven B. Hawthorne, Jaime Cesar, Bethany Kurz, Jeanne B. Percival
      First page: 779
      Abstract: The recovery factor in unconventional reservoirs is typically 5-10%, with extensive hydraulic fracturing and infill drilling to maintain the production rate. Concurrently, the rush towards decarbonization is opening up new possibilities for CO2 utilization, enhanced oil recovery (EOR) being one example. CO2-EOR in unconventional reservoirs presents an opportunity for both financial gain through improved recovery factors, as well as reducing the carbon footprint of the produced oil. In this work, we examine the CO2-EOR potential in 4 organic-rich shale samples from the Canadian Bakken Formation. A number of characterization tests alongside CO2 extraction experiments were performed to gain insight into the controlling factors of CO2-EOR in these ultra-tight formations. The results show CO2 can penetrate the tight rock matrix and recover a substantial amount of hydrocarbon. Concentration gradient driven diffusion is the dominant form of recovery.
      Citation: Minerals
      PubDate: 2022-06-19
      DOI: 10.3390/min12060779
      Issue No: Vol. 12, No. 6 (2022)
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