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This study aimed to investigate the impact of as-received biomass fly ashes (BFA) and green liquor dregs obtained from a pulp and paper plant in Brazil as substitutes for metakaolin in geopolymeric formulations. The properties of this type of waste material vary widely between different industrial plants. This study refrains from subjecting the waste materials to any form of pretreatment, taking into account their organic matter and particle size heterogeneity, requiring extensive characterization to evaluate their influence on the compressive strength, apparent open porosity, and water absorption of the geopolymeric samples. The objective was to assess their potential for upcycling purposes as an alternative to energy-intensive materials, such as ordinary Portland cement (OPC) and advanced ceramics. This potential arises from the ability of alkali-activated materials (AAM) to undergo curing at ambient temperatures, coupled with the possibility of compositions primarily derived from waste materials. To improve the sustainability of the products, the amorphous content of the raw material, which is more reactive than crystalline phases, was quantified and used as the base for mixture ratios. This approach aimed to reduce the requirement for alkaline activators, which have significant environmental impacts, while also increasing the waste content in the formulation. The incorporation of waste materials into the geopolymer matrix generally led to a reduction in the compressive strength compared to the benchmark metakaolin sample (19.4 MPa) but did not present a trend. The dregs led to values of 4.1 MPa at 25 wt% and 7.1 MPa at 50 wt%, a behavior that is somewhat counterintuitive, and BFA at 10 wt% presented 5.7 MPa. Nevertheless, the apparent open porosity remained at high levels for all the samples, close to 50%, and the compressive strength of most of them was over the values obtained for the metakaolin-only samples with mixture ratios calculated from the total composition instead of the amorphous composition. The decrease in strength and the increase in porosity were attributed to the specific characteristics of the waste materials, such as their high crystallinity, presence of organic matter, heterogeneous particle composition, and size. Overall, this study provides insight into the variations in geopolymerization based on the bulk and amorphous content of the aluminosilicate sources and how the characteristics of the waste materials influence the geopolymer matrix. It also highlights how calculating mixture ratios based on the amorphous composition improves the possibility of waste valorization through alkali activation. Additionally, it suggests that BFA and dregs might be effectively utilized in applications other than OPC substitution, such as adsorption, filtration, and catalysis. [ABSTRACT FROM AUTHOR]

The ionic rare earth (RE) ore body undergoes particle transport and pore structure change during the leaching process, resulting in "uneven percolation, preferential channel, leaching blind area," and other problems, leading to structural changes in the ore body, low leaching efficiency, and waste of resources. The unsaturated infiltration process is also the key stage that causes these problems. The initial pore structure evolution of the ore body plays a decisive role in the permeability coefficient of the ore body, and the direct influencing factor of the permeability coefficient is the distribution of the pore radius. We carried out research through indoor simulated leaching, the filter paper method for determining matrix suction, and nuclear magnetic resonance (NMR) testing. An ionic rare earth ore soil-water characteristic curve within a large matrix suction range was obtained by the filter paper method. With the increase in volumetric water content, the matrix suction presents a sharp downward trend. When the volumetric water content is less than 20%, this rule is particularly obvious. With the increase in matrix suction, the thickness of the adsorbed water film on the particle surface and pore radius show a decreasing power function trend. Under percolation, the porosity of an ionic rare earth ore sample tends to increase linearly with the increase in volumetric water content during the process from non-saturation to saturation; the porosity of a saturated ore sample after seepage expanded by 17.5 times compared to that of an unsaturated ore sample before seepage. The change rule of the internal microstructure of the ore sample is reflected in the gradual disappearance of micro pores and the gradual formation of small, medium, large, and mega pores, which shows a gradual increase trend. In the pore radius distribution, the more large and medium pores, the larger the permeability coefficient; the more micro and small pores, the smaller the permeability coefficient. For some ore bodies with poor permeability, the ore body is infiltrated with clear water under small water pressure before leaching with a leaching solution, which can improve the permeability of the ore body, effectively improve the efficiency of rare earth leaching, and increase the economic benefits. [ABSTRACT FROM AUTHOR]

Coal is expected to continue dominating the global energy landscape for a considerable period in the future. However, the depletion of high-quality coal resources and the increasing proportion of difficult-to-float coals are exacerbating environmental issues and leading to significant waste of carbon resources, making the clean and efficient utilization of such coals imperative. Enhancing the quality of coal through flotation is a prerequisite for the resource utilization of coal. Difficult-to-float coal, characterized by high hydrophilicity, complex pore structures, and fine particle size, poses challenges for efficient flotation using conventional collectors. Emulsions, owing to their exceptional surface and interfacial regulation capabilities and environmental adaptability, have been employed as flotation collectors for various minerals and have garnered significant attention in recent years for their application in the flotation of difficult-to-float coals. In the pursuit of green and cost-effective flotation technologies for such coals, this paper systematically reviews the causes of poor floatability in difficult-to-float coals and their latest research progress by emulsion flotation. It summarizes the impact of emulsion types and preparation methods on their properties and application areas, with a particular focus on the key mechanisms by which emulsion collectors enhance the flotation of difficult-to-float coals, including surface charge regulation, surface hydrophobicity modification, and interfacial tension control. Finally, this paper outlines future research directions on emulsion flotation, which will likely focus on the precise control of emulsion structure and size, the targeted separation of organic components by emulsion collectors under complex conditions, the development of low-cost and highly biocompatible synthetic reagents, and the development of efficient emulsion storage and transportation equipment. [ABSTRACT FROM AUTHOR]

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

This paper presents the results of a study of the mineralogical and chemical composition of zinc and lead metallurgical slags. These slags contain numerous elements, including toxic metals, which form conglomerates or multiphase intergrowths. The phase composition of slags is one of the main factors that determine their behaviour in weathering environments, that is, their ability to release metals when exposed to atmospheric factors. In this paper, the release of elements from slags and their mobility in a hypergenic environment is determined based on the results of leachability tests and on geochemical modelling, thus assessing the environmental impact of landfilled slags. The elements released from slags in the largest quantities are zinc and lead. Zn is leached out over a long period of time. It was found that after 12 years, the concentration of Zn in the eluate exceeds by 40 times the permissible value of 200 mg/kg for hazardous waste. The degree of leaching of lead from slags as a function of time (after 12 years), despite its significant solubility in water, is much lower than the degree of leaching of zinc. The most mobile phase components of slags in the studied hypergenic environment are the lead phases (anglesite and galena) and, to a lesser extent, the zinc phases (sphalerite and willemite). Anglesite and galena in almost the entire Eh-pH range, along with admixtures of elements, decompose into ionic forms: PbCl42−, Pb2+, and PbOH+. Sphalerite in the soil and water environment (oxidizing and acidic conditions) will decompose into the mobile ionic form Zn2+. Willemite, which is resistant to weathering, will undergo similar decomposition. It can therefore be assumed that the carriers of toxic metals are primarily lead sulphides and sulphates, zinc sulphides, and, less frequently, zinc, lead, and iron oxides. [ABSTRACT FROM AUTHOR]

This study investigates the genesis of analcite in black shale from continental lakes and its implications for hydrocarbon enrichment, with a case study of the Permian Pingdiquan Formation in the Junggar Basin, Xinjiang, China. As an alkaline mineral, analcite is extensively developed in China's lacustrine black shale hydrocarbon source rocks and is linked to hydrocarbon distribution. However, the mechanisms of its formation and its impact on hydrocarbon generation and accumulation remain insufficiently understood. This paper employs a multi-analytical approach, including petrological observations, geochemical analysis, and X-ray diffraction, to characterize analcite and its association with hydrocarbon source rocks. The study identifies a hydrothermal sedimentary origin for analcite, suggesting that it forms under conditions of alkaline lake water and volcanic activity, which are conducive to organic matter enrichment. The analcite content in the studied samples exhibits a significant variation, with higher contents associated with hydrocarbon accumulation zones, suggesting its role in hydrocarbon generation and accumulation. This paper reports that analcite-bearing rocks display characteristics of high-quality reservoirs, enhancing the permeability and porosity of the rock, which is essential for hydrocarbon storage and migration. In conclusion, this paper underscores the importance of analcite as a key mineral indicator for hydrocarbon potential in black shale formations and provides valuable insights for further geological and hydrocarbon exploration in similar settings. [ABSTRACT FROM AUTHOR]

Materials with high ion mobility are widely used in many fields of modern science and technology. Over the last 40 years, they have thoroughly changed our world. The paper characterizes the structural features of minerals and their synthetic analogs possessing this property. Special attention is paid to the ionic conductors with tetrahedral (zincite- and wurtzite-like), octahedral (ilmenite-like), and mixed (NASICON-like) frameworks. It is emphasized that the main conditions for fast ionic transport are related to the size and positions occupied by a mobile ion, their activation energy, the presence and diameter of conduction channels running inside the structure, isomorphic impurities, and other structural peculiarities. The results of the studies of solid electrolytes are dispersed in different editions, and the overview of new ideas related to their crystal structures was the focus of this paper. [ABSTRACT FROM AUTHOR]

Seismic exploration has caught widespread attention in metal ore exploration due to its higher resolution. However, the presence of topography and complex underground structures in metal ore exploration complicates seismic records. Therefore, it is essential to apply a numerical simulation method suitable for metal ore exploration to study the propagation law of seismic waves in shallow and ore-forming zones, providing reliable theoretical support for multi-component seismic techniques. In particular, the presence of topography generates strong-amplitude surface waves, scattered waves, and converted waves, which consistently distort seismic records and affect the imaging accuracy of the metallogenic belts. Additionally, the propagation of seismic waves is also affected by the anisotropy and viscoelasticity of the underground medium. This paper proposes an elastic wave finite-difference numerical simulation method suitable for irregularly topographical and complex medium conditions, named the comprehensive parameter correction method, which implements a free-surface boundary condition based on the concept of medium averaging. It is algorithmically simple and implies no additional computational costs. Meanwhile, the results obtained by this method are highly consistent with those of the spectral element method, demonstrating its accuracy. By presenting several numerical simulation cases and illustrating the impact of topography and medium conditions on seismic records, this paper demonstrates the necessity of considering irregularly topographical and complex medium conditions in metal ore exploration. In conclusion, the numerical simulation method we propose provides a solid theoretical foundation for the application of seismic exploration methods in metal ore exploration. [ABSTRACT FROM AUTHOR]

The edge detection method based on the magnetic gradient tensor data plays an important role in magnetic exploration because it is free from geomagnetic interference and contains more abundant information. This paper proposes a new anomaly edge detection method using the magnetic gradient tensor components. The model is established to compare with other methods, such as directional total horizontal derivative (THDz), analytical signal (AS), tilt angle, theta map, and so on, under conditions of vertical magnetization, oblique magnetization, and noise interference. Through the study of the anomaly distribution of the rectangular model, it is observed that the edge detection method proposed in this paper is nearly impervious to noise interference, exhibits strong anti-interference capabilities, delivers a high-quality boundary identification effect, and provides greater accuracy in anomaly edges with minimal error. When multiple anomalous bodies are present, the edge detection results are less susceptible to interference from each other, resulting in higher resolution. The efficiency of the algorithm is demonstrated by real magnetic data from some study areas in Jiangxi Province, China. The experimental results show that the proposed method is more precise and accurate than the total horizontal derivative, analytical signal, tilt angle, and theta map methods. [ABSTRACT FROM AUTHOR]

The awareness of tailings dam safety monitoring has widened due to the recent disasters caused by failures of such structures. The failure rate of tailings dams worldwide (i.e., the percentage of failed dams out of total) is estimated at 1.2%, compared to the 0.01% rate for traditional water dams. Most of the tailings dam monitoring guidelines suggest that the owner develops a robust surveillance program to detect possible indicators of potential failures. This paper presents a thorough review of major guidelines on tailings storage facility (TSF) monitoring and surveillance, the visual parameters to be monitored, as well as good practice in the development of monitoring systems. This paper reviews the recent literature with an emphasis on the development of monitoring systems utilizing sensors, unmanned aerial vehicles (UAVs), and satellite images that may be considered as supplementary guarantees against failure events. [ABSTRACT FROM AUTHOR]

Mississippi Valley-type (MVT) Pb-Zn deposits are a subtype of sedimentary-hosted mineralization. These deposits are hosted by carbonate sequences in passive-margin tectonic settings. This paper uses the Fry technique and distance distribution analysis to model the spatial distribution pattern of MVT Pb-Zn deposits in the west of Semnan province (Iran) and their association with some geological features, aiming at mapping mineral prospectivity in the area. The modeling results reveal that NE–SW trending faults and Permian-Cretaceous dolomites and limestone are, respectively, major structural and lithological controlling factors of mineralization that operate as conduits and physicochemical subsystems of ore formation. The integration of the corresponding evidence maps of the controlling factors with a model of the geochemical signature of MVT Pb-Zn deposits through a supervised random forest approach, a machine learning technique, gains an exceptional prospectivity map predicting 100% of the known MVT Pb-Zn deposits in only 15% of the study area, which is an achievement. The recognized targets can be planned for further exploration. [ABSTRACT FROM AUTHOR]

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

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

In this paper, the process of solid-state metalized reduction and magnetic separation was investigated for preparation of nickel–iron concentrate from a low-grade laterite nickel ore. The effects of reduction temperature, reduction time, amount of dosages, and magnetic field strength on grades and recoveries of nickel and iron were studied. The results showed that nickel–iron concentrate with a nickel grade of 7.32%, nickel recovery of 81.84%, iron grade of 78.74%, and iron recovery of 69.78% were obtained under the conditions of a reduction temperature of 1200 °C, reduction time of 120 min, calcium fluoride addition of 12%, ferric oxide addition of 10%, coal addition of 12%, and magnetic field strength of 170 kA/m. [ABSTRACT FROM AUTHOR]

Froth flotation, a widely used mineral beneficiation technique, generates substantial volumes of data, offering the opportunity to extract valuable insights from these data for production line analysis. The quality of flotation data is critical to designing accurate prediction models and process optimisation. Unfortunately, industrial flotation data are often compromised by quality issues such as outliers that can produce misleading or erroneous analytical results. A general approach is to preprocess the data by replacing or imputing outliers with data values that have no connection with the real state of the process. However, this does not resolve the effect of outliers, especially those that deviate from normal trends. Outliers often occur across multiple variables, and their values may occur in normal observation ranges, making their detection challenging. An unresolved challenge in outlier detection is determining how far an observation must be to be considered an outlier. Existing methods rely on domain experts' knowledge, which is difficult to apply when experts encounter large volumes of data with complex relationships. In this paper, we propose an approach to conduct outlier analysis on a flotation dataset and examine the efficacy of multiple machine learning (ML) algorithms—including k-Nearest Neighbour (kNN), Local Outlier Factor (LOF), and Isolation Forest (ISF)—in relation to the statistical 2 σ rule for identifying outliers. We introduce the concept of "quasi-outliers" determined by the 2 σ threshold as a benchmark for assessing the ML algorithms' performance. The study also analyses the mutual coverage between quasi-outliers and outliers from the ML algorithms to identify the most effective outlier detection algorithm. We found that the outliers by kNN cover outliers of other methods. We use the experimental results to show that outliers affect model prediction accuracy, and excluding outliers from training data can reduce the average prediction errors. [ABSTRACT FROM AUTHOR]

The issues of the same material with different spectra and the same spectra for different materials pose challenges in hyperspectral rock classification. This paper proposes a multidimensional feature network based on 2-D convolutional neural networks (2-D CNNs) and recurrent neural networks (RNNs) for achieving deep combined extraction and fusion of spatial information, such as the rock shape and texture, with spectral information. Experiments are conducted on a hyperspectral rock image dataset obtained by scanning 81 common igneous and metamorphic rock samples using the HySpex hyperspectral sensor imaging system to validate the effectiveness of the proposed network model. The results show that the model achieved an overall classification accuracy of 97.925% and an average classification accuracy of 97.956% on this dataset, surpassing the performances of existing models in the field of rock classification. [ABSTRACT FROM AUTHOR]

A large amount of pyrite concentrate slag washing solution is produced in China every year, and this contains valuable components such as Cu2+ and Au. The traditional treatment method not only pollutes the environment but also wastes metal resources. For the washing solution containing Cu2+ 437 mg/L and Au 0.13 mg/L, two new processes comprehensive recovery schemes were developed and compared in this paper, namely iron powder replacement pore filtration and neutralization precipitation pore filtration. When the iron powder replacement pore filtration process was adopted, Cu2+ and Au were mainly comprehensively recovered in the form of a mixture of sponge copper and particulate gold. The test results showed that the replacement optimal conditions involved a pH of 3.0, iron powder dosage of 6 g/L, and replacement time of 3.0 h. After replacement, the filter cloth with below 1 μm pore size was used for filtration. The recovery rate of Cu2+ in the washing solution was 98.13 and the total recovery rate of Au was 95.83%. Otherwise, when the neutralization precipitation pore filtration process was adopted, Cu2+ and Au were mainly comprehensively recovered in the form of a mixture of copper hydroxide and particulate gold. The test results showed that sodium hydroxide was used as the precipitant and the optimum neutralization pH value was 6.5. After precipitation, the filter cloth with a below 1 μm pore size was used for filtration. The recovery rate of Cu2+ in the washing solution was 97.35% and the total recovery rate of Au was 93.54%. The economic benefit estimation of the two processes showed that the neutralization precipitation pore filtration process had the advantages of low material consumption, low cost and high economic benefit. [ABSTRACT FROM AUTHOR]

Ore collection devices are important for the collection of deep-sea polymetallic nodules. Based on the CFD-DEM solid–liquid two-phase flow coupling calculation method, this paper simulated the rise and transport phases of polymetallic nodules using the Coanda effect ore collection device. The validity of the numerical simulation method was confirmed through experimental testing. On this basis, the effects of different working and structural parameters on the collection rate were studied. The results indicate that the flow rate of the collection jet and the bottom clearance were the primary factors affecting the collection rate of the polymetallic nodules. An increase in the collection jet flow rate leads to a substantial rise in the collection rate of polymetallic nodules. Conversely, an increase in bottom clearance results in a decrease in the collection rate. A collection rate exceeding 90% can be achieved in both scenarios: a 10 mm bottom clearance with an 8 m/s collection jet flow rate, and a 30 mm bottom clearance with a 10 m/s collection jet flow rate. The collection nozzle slant angle has no substantial impact on the collection rate, and the recommended collection nozzle slant angle is 35° to reduce energy loss. [ABSTRACT FROM AUTHOR]

The increased exploitation of ores leads to the generation of mining waste, which has a negative impact on the environment and human health. For this reason, it is necessary to take care of it in an adequate way by applying some of the possible treatments. In addition to protecting the environment by applying appropriate treatment, there is also the possibility of making a profit by valorizing useful elements from mining waste. In order to choose the most adequate treatment, it is necessary to perform the characterization of mining waste. This paper contains a detailed characterization of the flotation tailings deposited at the Old Flotation Tailings in eastern Serbia, originating from copper ore processing. Characterization includes physico-chemical analysis, polarizing microscope analysis, X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) analysis analysis. The obtained results indicate that the investigated flotation tailings can be used as a secondary raw material for metal recovery, in this case primarily copper (whose content is about 0.24%), gold (with a content of about 0.43 ppm) and silver (with a content of about 1.7 ppm). Considering that the content of valuable elements is quite low, it is suggested to apply hydrometallurgical treatment for their recovery. [ABSTRACT FROM AUTHOR]

The widespread use of clay minerals and clays in environmental engineering, industry, medicine, and cosmetics largely stems from their adsorption properties and surface charge, as well as their ability to react with water. The dissolution and growth of minerals as a function of pH are closely related to acid–base reactions at their surface sites and their surface charge. The vivid tapestry of different types of surface sites across different types of clay minerals generates difficulties in experimental studies of structure–property relationships. The aim of this paper is to demonstrate how a mesoscale stochastic kinetic Monte Carlo (kMC) approach altogether with atomistic acid-base models and empirical data can be used for understanding the mechanisms of dissolution and surface charge behavior of clay minerals. The surface charge is modeled based on equilibrium equations for de/protonated site populations, which are defined by the pH and site-specific acidity constants (pKas). Lowered activation energy barriers for these sites in de/protonated states introduce pH-dependent effects into the dissolution kinetics. The V-shaped curve observed in laboratory experiments is reproduced with the new kMC model. A generic rate law for clay mineral dissolution as a function of pH is derived from this study. Thus, the kMC approach can be used as a hypothesis-testing tool for the verification of acid–base models for clay and other minerals and their influence on the kinetics of mineral dissolution and growth. [ABSTRACT FROM AUTHOR]

The construction sector is among the most polluting industries globally, accounting for approximately 37.5% of the European Union's total waste generation in 2020. Therefore, it is imperative to develop strategies to enhance the sustainability of this sector. This paper proposes a multiscale COMSOL Multiphysics numerical model for an ex situ mineral carbonation process of hydrated lime. The carbonation process is characterized at both the micro- and macroscale levels, encompassing interactions within and between the particles. This model incorporates both reaction and diffusion phenomena, considering the effects of porosity and liquid-water saturation parameters. Generally, liquid-water saturation enhances the reaction kinetics but not CO2 diffusion, while porosity improves CO2 diffusion throughout the granular bed. The model has been experimentally validated, showing promising results by accurately characterizing carbonation tendencies and the influence of the CO2 flow rate and the initial water-to-solid ratio on the carbonation process. The proposed mathematical model facilitates the study of various parameters, including particle radius, reactor geometry, and material porosity. This analysis is valuable for both current and future projects, as it aims to identify the most profitable configurations for the hydrated lime carbonation process. [ABSTRACT FROM AUTHOR]

The high exploration and development production capacity of the Jiyang Depression, Bohai Bay Basin, China in the early stage confirms the huge exploration and development potential of shale oil in the study area. Due to the complexity of the depositional mechanism in the study area, the distribution law of fine-grained sedimentary rocks is not well understood, which restricts further exploration breakthroughs. This paper comprehensively observes rock cores and thin sections, combines mineral components, Rock-Eval pyrolysis, rock-cutting logging and logging data to classify lithofacies, and clarifies the distribution law of various lithofacies. The research results show that, according to lithological characteristics, various lithofacies origins are classified into three categories: terrigenous, mixed, and endogenous sources, and six lithofacies types are distinguished: terrigenous low-organic-matter massive siltstone (LF1), terrigenous low-organic-matter massive mudstone (LF2), mixed-source medium-organic-matter massive mudstone (LF3), mixed-source medium-to-high-organic matter laminated-massive mudstone (LF4), mixed-source medium-to-high-organic-matter laminated mudstone (LF5), and endogenous-sourced medium-to-high-organic matter laminated limestone (LF6). The distribution of lithofacies in plane is symmetrical in the east–west direction and is characterized by a banded distribution; the distribution in profile shows a stable depositional process and a continuous depositional sequence. The various lithofacies depositional models have been summarized; the terrigenous input from the northern steep-slope zone has influenced the hydrodynamic conditions of the lake basin, significantly affecting the lithofacies depositional variations from the steep-slope zone to the deep-sag area. The geological evaluation of each lithofacies has been conducted; LF1 + LF4 + LF5 are classified as Class I—target reservoirs for shale oil development, while LF3 + LF6 are considered Class II—favorable reservoirs. The result of the study provide a reference for the classification of fine-grained sedimentary-rock facies and distribution characteristics, and the evaluation of shale-oil-reservoir sweet spots in graben lake basins. [ABSTRACT FROM AUTHOR]

This study explores the effect of steel ball size and proportion on mineral grinding characteristics using Discrete Element Method (DEM) simulations. Based on batch grinding kinetics, this paper analyzes the contact behavior during grinding, discussing particle breakage conditions and critical breakage energy. The results indicate that while increasing the size of the steel balls leads to higher collision energy, the collision probability decreases significantly; the opposite is true for smaller steel balls. Simulation results with different ball size combinations show that increasing the proportion of smaller balls does not significantly change the collision energy but greatly increases the collision probability, providing a basis for optimizing ball size distribution to improve grinding performance. Furthermore, appropriately increasing the proportion of smaller balls can reduce fluctuations in grinding energy consumption, thereby enhancing collision energy and collision probability while reducing energy costs. Liner wear results demonstrate that larger ball sizes increase liner wear, but different ball size combinations can effectively distribute the forces on the liner, reducing wear. [ABSTRACT FROM AUTHOR]

In contemporary society, rich in mineral resources, efficiently and accurately identifying and classifying minerals has become a prominent issue. Recent advancements in artificial intelligence, particularly breakthroughs in deep learning, have offered new solutions for intelligent mineral recognition. This paper introduces a deep-learning-based object detection model for intelligent mineral identification, specifically employing the YOLOv8 algorithm. The model was developed with a focus on seven common minerals: biotite, quartz, chalcocite, silicon malachite, malachite, white mica, and pyrite. During the training phase, the model learned to accurately recognize and classify these minerals by analyzing and annotating a large dataset of mineral images. After 258 rounds of training, a stable model was obtained with high performance on key indicators such as Precision, Recall, mAP50, and mAP50–95, with values stable at 0.91766, 0.89827, 0.94300, and 0.91696, respectively. In the testing phase, using samples provided by the Geological and Mineral Museum at the School of Earth Sciences and Engineering, Sun Yat-sen University, the model successfully identified all test samples, with 83% of them having a confidence level exceeding 87%. Despite some potential misclassifications, the results of this study contribute valuable insights and practical experience to the development of intelligent mineral recognition technologies. [ABSTRACT FROM AUTHOR]

The Iberian Pyrite Belt (IPB) represents one of the largest districts of volcanogenic massive sulfide (VMS) deposits in the world, and is a critical source of base metals (Cu, Pb, and Zn) for Europe. Confirmed resources exceed 1700 Mt of massive sulfides with grades of around 1.2% Cu, 1% Pb, and 3% Zn as well as more than 300 Mt of stockwork-type copper mineralization. Significant resources of Sn, precious metals (Au and Ag), and critical metals (Co, Bi, Sb, In, and Se) have also been evaluated. The genesis of these deposits is related to a complex geological evolution during the late Devonian and Mississippian periods. The geological record of such evolution is represented by three main lithological units: Phyllite–Quartzite Group, the volcano–sedimentary Complex (VSC), and the so-called Culm Group. The sulfide deposits are located in the VSC, associated with felsic volcanic rocks or sedimentary rocks such as black shales. The massive sulfide deposits occur as tabular bodies and replacement masses associated with both volcanic and sedimentary rocks. Their mineralogical composition is relatively simple, dominated by pyrite, chalcopyrite, sphalerite, and galena. Their origin is related to three evolutionary stages at increasing temperatures, and a subsequent stage associated with the Variscan deformation. The present paper summarizes the latest developments in the IPB and revises research areas requiring further investigation. [ABSTRACT FROM AUTHOR]

A number of regolith-hosted REE occurrences have recently been discovered in the Esperance region in southern Western Australia. This paper summarizes major characteristics of REE mineralization and discusses contributing factors and potential controls. The main aim is to explain why there is a lack of highly sought-after ion-adsorption-clay-type REE deposits across the region despite the presence of the regolith-hosted REE mineralization on a regional scale. Local mineralization mostly occurs as continuous flat-lying enrichment "blankets" within the residual regolith developed over Archaean–Proterozoic granite gneisses and granitoids with elevated REE content. The enriched horizon is commonly located in the lower saprolite and saprock and is accompanied by an overlying REE-depleted zone. This distribution pattern, together with the data on HREE fractionation and the presence of the supergene REE minerals, indicates chemogenic type enrichment formed by supergene REE mobilization into groundwater, downward transport, and accumulation in the lower part of the weathering profile. Residual REE accumulation processes due to bulk rock volume and mass reduction during weathering also contribute to mineralization. It is proposed that climate and groundwater chemistry are the critical regional controls on the distribution of REEs in the weathering profile and on their speciation in the enrichment zone. Cenozoic aridification of climate in southwest Australia heavily overprinted pre-existing REE distributions in the weathering profile. Acidic (pH < 4), highly saline groundwaters intensely leached away any relatively weakly bound, adsorbed or colloidal REE forms, moving them downward. Dissolved REEs precipitated as secondary phosphates in neutral to alkaline environment at lower Eh near the base of the weathering profile forming the supergene enrichment zone. Low denudation rates, characteristic of areas of low relief under the arid climate, are favourable for the preservation of the existing weathering profiles with REE mineralization. [ABSTRACT FROM AUTHOR]

Nanofibrous clay minerals, specifically palygorskite (Pal) and sepiolite (Sep), have been becoming a new generation of rheological additives for drilling fluid systems due to their unique nanostructure, high performance, environmentally benign nature, and cost-effectiveness. These nanoclay minerals exhibit excellent colloidal and rheological properties in aqueous systems, even in saline and high-temperature environments. Although Pal and Sep have been employed as auxiliary rheological additives in a few cases to enhance the salt resistance of conventional water-based drilling fluids (WBDFs), these two clay minerals have not yet been used on a large scale due to a lack of understanding of their structures and properties, as well as the control of their performance. This paper presents a comprehensive review of the clay mineralogy, colloidal chemistry, rheological behaviors, and filtration properties of nanofibrous clay minerals in WBDFs, with critical comments. It also discusses the challenges and prospects for further research. This review provides new insights into fundamental and applied studies of nanofibrous clay minerals and helps promote the large-scale application of nanofibrous clay products in drilling fluids. [ABSTRACT FROM AUTHOR]

The Uhelchulu quartz diorite-granodiorite intrusions in Xiwuqi, Inner Mongolia, are exposed along the northwestern margin of the Xilinhot microcontinental block, located within the central and eastern parts of the southeastern Hegenshan suture zone. LA-ICP-MS zircon U-Pb dating yielded crystallization ages of (396 ± 8) Ma for the quartz diorite and (385 ± 5) Ma for the granodiorite, indicating an Early-Middle Devonian magmatic event. The quartz diorite exhibits I-type granite features, characterized by elevated Al2O3 (14.33–15.43 wt%), MgO (3.73–5.62 wt%), and Na (Na2O/K2O = 1.04–1.44), coupled with low P2O5 (0.15–0.20 wt%) and TiO2 (0.73–0.99 wt%). Trace element patterns show relative enrichments in Rb, Th, U, and Pb, while Nb, Ta, Sr and Ti are relatively depleted. Total REE contents are relatively low (123–178 ppm), with significant LREE enrichment (ΣLREE/ΣHREE = 4.75–5.20), and a non-obvious Eu anomaly (δEu = 0.75–0.84). In contrast, the granodiorite displays S-type granite characteristics, with high SiO2 (70.48–73.01 wt%), K (K2O/Na2O = 1.35–1.83), Al2O3 (A/CNK = 1.16–1.31), and a high differentiation index (DI = 76–82). Notably, MgO (1.44–2.24 wt%) contents are low, and significant depletions of Ba, Sr, Ti, and Eu are observed, while Rb, Pb, Th, U, Zr, and Hf are significantly enriched. Total REE contents are relatively low (178–314 ppm), exhibiting significant LREE enrichment (LREE/HREE = 6.17–8.36) and a pronounced negative Eu anomaly (δEu = 0.34–0.49). The overall characteristics point towards an active continental margin arc background for the Uhelchulu intrusions. Previous studies have suggested that the Hegenshan ocean continuously subducted northward from the Early Carboniferous to the Late Permian, but there is a lack of evidence for its geological evolution during the pre-Early Carboniferous. Therefore, this paper provides a certain basis for studying the geological evolution during the pre-Early Carboniferous in the Hegenshan ocean. We preliminarily believed that the Hegenshan ocean underwent a southward subduction towards the Xilinhot microcontinental block in the Xiwuqi area, at least from the Early Devonian to the Middle Devonian and the Hegenshan ocean may might have undergone a shift in subduction mechanism during the Late Devonian or Early Carboniferous. [ABSTRACT FROM AUTHOR]

Phosphate ore is the dominating natural resource for the production of fertilizers and phosphorous chemical products. Flotation is the most widely employed technique to enrich apatite and remove the impurities for the separation of the phosphate ore. The flotation reagents play an important role in this efficient separation of phosphate ores. In the last few decades, great progress has been achieved in the flotation reagents for phosphate ores. However, a critical review on this theme has rarely been reported in recent years. Thus, the goal of this paper is to critically analyze the published literature on the flotation reagents for phosphate ores, mainly ranging from 2010 to 2024, including the regulators, depressors, collectors, and frothers. Additionally, the interaction mechanisms between the reagents and mineral surfaces were analyzed. It is concluded that sulfuric acids and its derivatives play a leading role in the depression of phosphate minerals. Highly selective biobased depressants have become potential carbonate inhibitors. Additionally, the derivatization and synthesis of multi-functional compounds and identifying the biobased frothers are the main development trends of collectors and frothers. Overall, a high-quality concentrate with a 31.05% grade and 98.21% recovery at pH 5 was achieved using lecithin as an ecofriendly amphoteric collector and sulfuric acid as the depressor when the feed contained 24.49% P2O5, which was superior to other flotation indexes of similar phosphate ores. This review will help researchers to document knowledge gaps and provide a reference for the efficient and green beneficiation of phosphate ores in the future. [ABSTRACT FROM AUTHOR]

This study advances our understanding of the Jiangnan Orogenic Belt by integrating high-precision geochronological data with interpretations of sedimentary and tectonic environments. Specifically, it addresses the controversy over the geological significance, origins, and tectonic significance of the Shengong Unconfomity: at the base of the Luojiamen Formation. This paper shows that the formation developed over four stages with the primary source of detritus lying in a volcanic arc to the south. The study also reassesses the "unconformity" between the Luojiamen Formation of the Heshangzhen Group and the Zhangcun Formation of the Shuangxiwu Group, concluding that it does not demarcate the end of the orogenic collision between the Cathaysia and Yangtze blocks. [ABSTRACT FROM AUTHOR]

This paper studies the process mineralogy, mechanism, and kinetics of column leaching behavior of low-grade high-calcium–magnesium copper ore. The effect of sulfuric acid concentration, leach solution spraying intensity, and material particle size on column leaching kinetics is discussed. The kinetic analysis of column leaching of copper indicates that sulfuric acid concentration has a significant impact. As sulfuric acid concentration increases, the limiting step of reaction shifts from chemical reaction control to a combination of chemical reaction and diffusion mixing control. Spraying intensity also affects copper column leaching; increasing intensity shifts the limiting step from diffusion control to mixing control, thereby mitigating the effects of diffusion control. Regarding other elements, it is found that iron leaching is primarily controlled by chemical reaction, while calcium leaching is mainly controlled by chemical reaction. As sulfuric acid concentration increases from 10 g/L to 20 g/L, the limiting step for calcium leaching shifts from chemical reaction control to chemical reaction and diffusion-mixing control. [ABSTRACT FROM AUTHOR]

Gypsum is a common mineral at Gale crater on Mars, currently being explored by the Mars Science Laboratory (MSL) rover, Curiosity. In this paper, we summarize the associations of gypsum with other sulfate minerals (bassanite, anhydrite, jarosite, starkeyite, and kieserite) from the lowest levels of the crater's northern moat zone (Aeolis Palus) up through ~0.8 km of the stratigraphic section in the lower slopes of the sedimentary mound developed around the central peak, Aeolis Mons (informally, Mount Sharp). The analysis is based on results from the CheMin X-ray diffraction instrument on Curiosity, supplemented with information from the rover's versatile instrument suite. Gypsum does not occur with the same frequency as less hydrous Ca-sulfates, likely, in most cases, because of its dehydration to bassanite and possibly to anhydrite. All three of these Ca-sulfate phases often occur together and, along with other sulfates, in mixed assemblages that are evidence of limited equilibration on a cold, dry planet. In almost all samples, at least one of the Ca-sulfate minerals is present, except for a very limited interval where jarosite is the major sulfate mineral, with the implication of more acidic groundwater at a much later time in Gale crater's history. Although observations from orbit reveal a sulfate-rich surface, currently active dark basaltic dunes at Gale crater have only small amounts of a single sulfate mineral, anhydrite. Gale crater has provided the most complete mineralogical analysis of a site on Mars so far, but the data in hand show that Gale crater mineralogy is not a blueprint with planet-wide application. The concurrent study of Jezero crater by the Mars 2020 mission and comparisons to what is believed to be the most extensive deposit of gypsum on Mars, in the dune fields at the north polar ice cap, show significant diversity. Unraveling the stories of gypsum and other sulfates on Mars is just beginning. [ABSTRACT FROM AUTHOR]

Heap bioleaching is considered to be a less energy-intensive metal-extraction technique compared to other methods, making it particularly attractive for low-grade sulfide ores. It has been successfully applied to recovery of copper, gold, and uranium from ores over decades. Despite its seemingly straightforward nature, heap bioleaching can experience failures if the ore is unsuitable or the heap leach process is not thoroughly investigated and well-developed. Therefore, multidisciplinary approaches are essential for research and development in heap bioleaching, as its performance depends on numerous processes operating across a wide range of length scales. This review focused on the current state of knowledge regarding the understanding of multi-scale mechanisms in heap bioleaching and the use of multidisciplinary approaches at different scales to develop the process. The investigation covered various scales, such as atomic and molecular, mineralogy and microbes, reaction particles, heap bioleaching units and full-scale factory production. Different approaches were employed to gain a comprehensive understanding of the microbial molecular structure and metabolism, the structure and reaction of minerals, microbial–mineral interaction, particles and aggregation states, and multiphase flow transfer, as well as laboratory experiments, modeling, industrialization, and operation optimization. We emphasized the need for collaboration among researchers from different disciplines and stress the importance of considering the coupling effects of physical, chemical, and microbiological factors when running heap bioleaching plants. Such collaboration and coupling are vital for successful implementation and optimization of heap bioleaching processes. This paper aimed to provide a comprehensive overview of current research related to heap bioleaching at different scales and disciplines, and gave implications to heap bioleaching technology development. [ABSTRACT FROM AUTHOR]

This paper focuses on the role of the most common mineralogical techniques applied to the identification of the different statuary qualities in white, grey, and black Göktepe marble. For this purpose, the case of a Roman sculpture marble collection from the rural villa of Valdetorres de Jarama (central Iberia), dating to the 4th century AD, is presented. The mythological statuary, combining white, grey, and black marbles, is one of the most outstanding marble collections in the Aphrodisian style found in Hispania. The analytical results (achieved through Petrography, Cathodoluminescence, C and O isotopes, and Sr and Mn concentration) support the identification of two varieties of "black" Göktepe, traditionally referred to as bigio morato and bigio antico, as well as the best statuary quality of white Göktepe. In addition, the analytical identification of other Asiatic marbles in the Valdetorres collection, a white coarse-grain originally from the quarries of Aphrodisias city, and one small piece identified as Carian red from Iasos, corroborates the already suggested strong connection existing between artists and the stone material they chose for their works. Finally, the identification carried out on the marble of the bases that served as seats for the sculptures is noteworthy, as it is a white marble of lower quality whose analytical characteristics are consistent with the Microasiatic marble of Denizli. The use of these exotic and exceptional raw materials confirms the taste for luxury and decorative richness in Late Antique Hispanic rural villae and contributes to a better understanding of the distribution of Aphrodisian production and trade networks with the Western Roman provinces. [ABSTRACT FROM AUTHOR]

The present paper describes the technological solution for obtaining Cu, Zn, Pb, and Ag from jarosite waste raw material, with its simultaneous separation from In and Fe. By roasting at low temperatures, iron was transformed from the Fe2(SO4)3 form into Fe2O3, which is insoluble in water and slightly soluble in acid. Copper sulfate and zinc sulfate are present in jarosite as sulfates. During temperature roasting, the copper and zinc were still in the form of CuSO4 and ZnSO4, i.e., they were easily dissolved in water. This procedure led to good selectivity of Cu and Zn compared to Fe. After water leaching, PbSO4 and Ag2SO4 remained in the solid residue. By treating jarosite with a content of 0.7% Cu, 5.39% Zn, and 5.68% Pb, products of commercial quality were obtained. By roasting jarosite in an electric furnace and leaching the roasted sample in water, leaching degrees of 91.07%, 91.97%, and 9.60% were obtained for Cu, Zn, and Fe, respectively. Using 1 M NaOH in the leaching solution, 99.93% Fe was precipitated to pH = 4. Cu in the form of CuSO4 was further treated by cementation with Zn, after which cement copper was obtained as a commercial product. Zn in the form of ZnSO4 was further treated by precipitation with Na2CO3 to obtain ZnCO3 concentrate of commercial grade. The total recovery of Pb and Ag, which were treated by chloride leaching, was 96.05% and 87.5%, respectively. The resulting NaPbCl3 solution was further treated with Na2CO3 solution, whereby PbCO3 was obtained as a commercial product. The produced PbCO3 could be further subjected to roasting to obtain soluble PbO. In these investigations, PbCO3 was smelted where a Pb anode was obtained; this was electrolytically refined to a Pb cathode. The proposed process does not pollute the environment with As and Cd. [ABSTRACT FROM AUTHOR]

The comment by Yin (2024) referred to the systematic morphology and identification of the newly recovered in situ ammonite assemblage Tiltoniceras sp. and Hildoceratidae sp. from the Bilong Co section in the Qiangtang Basin. Yin (2024) suggests that Tiltoniceras sp. should be assigned to Oxycerites aspidoides. Upon re-examination of our paper and the reply to the released comment, it is demonstrated that the morphologic characteristics of the recovered ammonites are more consistent with Tiltoniceras rather than Oxycerites aspidoides. These ammonites, along with in situ calcite U–Pb age (ca. 181 Ma), carbon isotope stratigraphy, and age-diagnostic palynomorphs, constrain the age of the Bilong Co oil shale to the Lower Jurassic (Toarcian) with plausible credentials. [ABSTRACT FROM AUTHOR]

The Mazarrón 2 shipwreck was found in 1994 on the beach of Playa de la Isla (Mazarrón, Murcia, Spain). This finding is extremely important because the boat and its lead cargo were still in a reasonable conservation state and, therefore, provided new data on naval construction, commercial goods, navigation routes, and the relationships between the Phoenicians and the local population in the 7th–6th century BC. Currently, the shipwreck remains underwater, protected by a metallic coffer. In the last 2 years, a Preliminary Studies Project has been carried out, supported by national and regional public institutions. This research aims to know the shipwreck's conservation state and to determine the extraction and conservation methods at the Museo Nacional de Arqueología Subacuática ARQVA (Cartagena, Spain), where the conservation and restoration treatment will be conducted. The sampling strategy and analytical study included not only wood and other materials from the shipwreck and its cargo but also the seawater and the seabed materials in the vicinity of the shipwreck. This paper presents the results of the geochemical study of the archeological site. The applied methodology included physico-chemical tests, X-ray diffraction, optical microscopy, FTIR spectroscopy, field-emission scanning electron microscopy coupled with X-ray microanalysis, and X-ray microscopy. The results indicated that, despite the wreck being buried at a shallow depth (less than 50 cm) in a marine environment with a water column of 2–2.5 m, influenced by complex coastal dynamics that favor an oxic environment, early diagenetic processes like the formation of pyrite framboids are particularly intense in the pores and internal channels of the wreck's wood, where a different dysoxic–anoxic environment prevails. These processes have been the main mechanisms to have affected the wreck and are related to the biogeochemistry of sediments. The sediments have been confirmed to be closely related to the geological context of the Mazarrón region. The conducted study found no significant evidence of pollution due to the lead cargo. [ABSTRACT FROM AUTHOR]

The Geopyörä breakage test uses two counter-rotating wheels to nip and crush rock specimens with a tightly controlled gap between rollers. This paper presents the detailed measures conducted to evaluate the accuracy and precision of energy measurements across various ore types using the Geopyörä. Force measurement was assessed just for its precision. The outputs were compared directly to the drop weight test (DWT) measures of fragmentation at the same energy and fitted A and b parameters. Test reproducibility was evaluated using a Round-Robin methodology, testing several samples in multiple laboratories. The results confirmed that the new test has sufficient accuracy to match DWT results and excellent precision to assure reproducibility. [ABSTRACT FROM AUTHOR]

This paper explores the efficiency and potential of indirect freeze crystallization (IFC) as a valuable resource-recovery technology in wastewater treatment, particularly focusing on acid mine water and hazardous material wastewater-treatment plants. Wastewater treatment poses challenges to recovering valuable resources effectively, enforcing the need for sustainable and resource-efficient technologies like freeze crystallization. Through a thorough examination of IFC principles and mechanisms, this paper aims to highlight its applications, advantages, and limitations. The investigation includes a comprehensive literature review and detailed methodology from one of the IFC pilot plants, as well as a critical analysis of the environmental and economic implications of IFC. By addressing scaling challenges in reverse osmosis and proposing an environmentally friendly brine disposal method through IFC, this paper contributes to reducing the environmental footprint associated with wastewater treatment. Additionally, this paper highlights the importance of extracting valuable resources from highly saline water and emphasises the potential economic and environmental benefits of resource recovery, particularly focusing on the promising technology of IFC. [ABSTRACT FROM AUTHOR]

Kaolin-group minerals occur in nature as the result of high-sulfidation acid sulfate, sulfur-poor HCl-, HF- and H2CO3-rich acidic fluid-related hydrothermal alterations and in situ geochemical weathering. These minerals possess different crystallographic and chemical properties that determine their application areas, mainly in the ceramic and paper industries, and as nanocomposite materials. The physicochemical properties of hydrothermal kaolin deposits are the result of the type of parent rock, the effect of the regional tectonism-associated magmatism, and the chemical features of hydrothermal fluids that interact with the deep basement rocks. However, understanding these geothermal systems is one of the most challenging issues due to the rich mineralogical assemblages, complex geochemistry and isotopic data of hydrothermal alteration zones. This study evaluates the formation of hydrothermal-origin kaolin-group minerals by considering their characteristics of hydrothermal alteration, isotopic compositions and differences in characteristic properties of low- and high-sulfidation occurrences; this paper also addresses mineralogical and structural differences between hypogene and supergene kaolin formations, and kaolin–alunite–pyrophyllite association, and it provides examples of worldwide occurrences. The study of the mineralogical assemblages, geochemistry and isotopic data of the hydrothermal alteration zones is one of the most challenging subjects in terms of gaining a detailed understanding of the geothermal systems. Silicification processes are subsequent to late-stage alteration after the completion of kaolinization processes, erasing existing hydrothermal mineralogical and geochemical traces and making interpretation difficult. In the early stages involving magmatic–hydrothermal-origin acidic geothermal fluids, the latter comes from the disproportionation of SO2 (+H2O) and H2S oxidation to H2SO4 in hydrothermal environments. In the later stages, due to spatial and temporal changes over time in the chemistry of geothermal fluids, the system comes to have a more alkali–chloride composition, with neutral pH waters frequently saturated with amorphous silica which characteristically precipitate as siliceous sinter deposits containing large amounts of opal-A. [ABSTRACT FROM AUTHOR]

The pre-Jurassic in the north depression of the Tuha depression is the most favorable replacement strata to obtain new reserves in the Turpan–Hami Basin. (Pre-Jurassic, in this paper, refers to the Permian and Triassic.) The main source rocks are the Taodonggou Group, of which the burial history and hydrocarbon generation potential remain unconfirmed. The investigation of the burial and thermal history is vital for the basin analysis and hydrocarbon exploration. Therefore, in this paper, by using the acoustic time difference method, vitrinite reflectance method, stratigraphic trend method and PetroMod-1D software, the differential characteristics of denudation thickness, burial history and thermal evolution history of different tectonic units in different periods of Taibei Sag in the Turpan–Hami basin are studied, and their influence on the petroleum system is analyzed, and then the zones with exploration potential are optimized. The results show that the Taibei Sag has experienced multiple tectonic uplift events. The Late Indosinian movement has profound effects on the Taodonggou Group source rocks. The rather large uplift amplitude postpones the maturation of source rocks. In addition, the Turpan–Hami Basin is a typical cold basin. Therefore, the thermal maturity of the source rocks is relatively low, with respect to the relatively deep burial. The thermal histories of the different sub-sags in the study area are slightly differentiated from each other. The Taodonggou Group source rocks in the Taibei Sag generally became mature during the Mid–Late Jurassic epoch, except for those in the Central–Southern Shanbei sub-sag, represented by Well LT-1, which reached the mature stage during the Late Triassic epoch. The study area has well-developed reservoir rocks, and effective reservoir bodies are formed in the slope zone and near the Tainan Sag, due to the higher porosity and permeability of reservoir rocks. The statistics related to the faults and an analysis of the structural styles of oil reservoirs indicate that the structural slope and anticline of the Huobei, Lianbei and Shanbei sub-sags are favorable for increasing reserves and production of hydrocarbons. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesized the information derived from more than 20 papers and PhD theses on the anisotropy of the magnetic susceptibility (AMS) of 19 Variscan granite plutons, spanning the period between 320 Ma and 296 Ma. The AMS data are obtained from 876 sampling sites with more than 7080 AMS measurements and a re-interpretation is proposed. The studied granites exhibit a magnetic susceptibility (Km) ranging from 30 to 10,436 × 10−6 SI units. Most granites typically exhibit Km values below 1000 × 10−6 SI, indicative of paramagnetic behavior. Biotite serves as the main carrier of iron (Fe), emphasizing the reduced conditions prevalent during the formation of granite melts in the Variscan orogeny. The AMS fabrics of the studied granite plutons record the magma strain, expressing the chronologic evolution of the stress field during the orogeny. This chronologic approach highlights the magmatic events between around 330 and 315 Ma, occurring in an extensional regime, in which the Borralha pluton is an example of a suite that recorded this extensional AMS fabric. Plutons with ages between 315 and 305 Ma show AMS fabrics, pointing out their emplacement in a compressional tectonic regime related to the Variscan collision. The plutons, younger than 305 Ma, record AMS fabrics indicating that the tectonic setting for emplacement changes from a wrench regime to an extensional one at the end of the collision stage. This is evident as there is a chronological overlap between the granites that exhibit AMS fabrics indicating extension and the ones that have AMS fabrics indicating a wrench regime. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the implementation of artificial self-awareness mechanisms and self-reflection abilities in deep neural networks. While the current limitations of research prevent achieving cognitive capabilities on par with natural biological entities, the incorporation of basic self-awareness and self-reflection mechanisms in deep learning architectures offers substantial advantages in tackling specific problems across various scientific fields, including geosciences. In the first section, we outline the foundational architecture of our deep learning approach termed Self-Aware Learning (SAL). The subsequent part of the paper highlights the practical benefits of this machine learning methodology through synthetic tests and applications addressed to automatic classification and image analysis of real petrological data sets. We show how Self-Aware Learning allows enhanced accuracy, reduced overfitting problems, and improved performances compared to other existing methods. [ABSTRACT FROM AUTHOR]

Ion-adsorption-type rare earth ores (IRE-ores) are a vital source of rare earth elements globally. The percolation properties of the ore body significantly determine the ease of rare earth extraction using in situ leaching processes. This paper investigates the interactions among clay particles in ion-adsorption-type rare earth ores within aqueous solutions, utilizing methods such as mineral particle aggregation and settling and acid–base adsorption on mineral surfaces. Based on these analyses, this paper elucidates the influence of solution properties on the percolation process of ion-type rare earth ores during leaching. The results indicate that the electrostatic attraction between minerals in aqueous solutions is pronounced, enhancing the interaction and resulting in a notable instability of the aggregates. The aggregation of minerals impacts the viscous effect of water bound to the mineral surface on the solution, thereby affecting the percolation rate. Extremely low concentrations of SO42− and CH3COO− can act as surface modifiers, reducing the electrostatic attraction between particles and consequently increasing the leaching percolation rate. [ABSTRACT FROM AUTHOR]

Oxide copper minerals are commonly extracted via acidic leaching, using acids such as H2SO4, HCl, or HNO3. These strong acids are the most widely used because of their high dissolution kinetics. However, their main concern is the high acid consumption because copper oxide deposits contain large amounts of acid-consuming gangue. This paper proposes using an alternative aqueous alkaline monosodium glutamate (MSG) system to leach copper oxide minerals. Tenorite (CuO) was used as the copper oxide mineral under study. The influence of process variables (such as temperature and glutamate concentration) and kinetics of this system on copper leaching from tenorite were studied. The results showed that temperature has a significant effect on copper dissolution rates. Increased temperature from 15 °C to 60 °C enhanced the copper extraction from 9.1% to 97.7% after 2 h. Leaching kinetics were analyzed using the shrinking core model (SCM) under various conditions, indicating that the leaching rate presented a mixed control. This method, however, fails to describe leaching for broad particle sizes due to its requirement for single-sized solid grains. This study demonstrated that a large particle size distribution in tenorite supported a successful extension of the SCM for leaching it from mixed glutamate solutions. The activation energy for the 15–60 °C temperature range was calculated to be 102.6 kJ/mol for the chemical control. [ABSTRACT FROM AUTHOR]

Super-reduced phases (SRPs), such as silicon carbide (SiC) and metal silicides, have increasingly been reported in various geological environments. However, their origin remains controversial. SRP inclusions (e.g., metal silicides and metallic silicon (Si0)) within SiC are commonly believed to indicate a natural origin. Here, we identified an unusual SRP assemblage (SiC, (Fe,Ni)Si2, and Si0) in situ in an H5-type Jingshan ordinary chondrite. Simultaneously, our analysis showed that the SiC abrasives contain (Fe,Ni)Si2 and Si0 inclusions. Other inclusions in the artificial SiC were similar to those in natural SiC (moissanite) reported in reference data, including diverse metal silicides (e.g., FeSi, FeSi2, Fe3Si7, and Fe5Si3), as well as a light rare earth element-enriched SiO phase and Fe-Mn-Cr alloys. These inclusions were produced by the in situ reduction of silica and the interaction between Si-containing coke and hot metals during the synthesis of the SiC abrasives. The results demonstrate that the SRP assemblage in the Jingshan chondrite originates from abrasive contamination and that the SRP inclusions (with a low content of Ca, Al, Ti, and Zr) cannot be used as a conclusive indicator for natural SiC. Additionally, the morphologies, biaxiality, and polytypes (determined by Raman spectroscopy) of SiC abrasives bear resemblance to those reported for natural SiC, and caution must be exercised when identifying the origin of SRP in samples processed by conventional methods using SiC abrasives. At the end of this paper, we propose more direct and reliable methods for distinguishing between natural and synthetic SiC. [ABSTRACT FROM AUTHOR]

The dynamics of milling circuits, particularly those involving Semi-Autogenous Grinding (SAG) mills, are not adequately studied, despite their critical importance in mineral processing. This paper aims to investigate the dynamic behavior of an SAG mill pebble recycling circuit under varying feed ore conditions, focusing on both uncontrollable parameters (such as ore hardness) and controllable parameters (including circuit layout and pebble crusher configurations). The study is carried out with Simulink dynamic simulations. Our findings reveal several key insights. Firstly, plant designs based solely on static simulations may not be adequate for large or complex circuits, as they fail to account for the dynamic nature of milling processes. Second, incorporating stockpiles after pebble crushing can effectively mitigate the impact of dynamic fluctuations, leading to more stable circuit performance. Third, different circuit layouts can facilitate easier maintenance and operational flexibility. Notably, finer pebble crushing can enhance circuit throughput by 5% to 10%. [ABSTRACT FROM AUTHOR]

The airborne electromagnetic system MobileMT exploits natural fields in a broadband frequency range with offset measurements of magnetic and electric field variations. It was introduced in 2018 and has since been developed in various configurations, each tailored to meet the demands of different exploration tasks, varied terrains, and geoelectrical conditions and support time-domain data with controlled primary field sources. There are four distinct airborne systems: the original MobileMT; the lighter configuration, MobileMTm; the configuration for a drone carrier, MobileMTd; and the innovative time-domain AFMAG hybrid, TargetEM. The paper describes the technical features of each system, their differences and inherent strengths, the optimal usage conditions, and insights into their applications under different conditions across various exploration tasks. Several field case studies are provided to support the natural field electromagnetics capabilities of recovering geological structures in a wide depth range, beginning from the near surface, and address the impact of parasitic IP effects on time-domain data. [ABSTRACT FROM AUTHOR]

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

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