Passos do Carmo Caliméria, Vanderhaeghe Olivier, Laurent Oscar
et al.
The architecture of the crust in the French Massif Central (FMC) is described as a nappe stack composed, from top to bottom, of the Upper Gneiss Unit (UGU), the Lower Gneiss Unit (LGU), and the Para-Autochthonous Unit (PAU), which are intruded by Carboniferous granitic plutons. In the Pontgibaud region, the Upper Gneiss Unit/Lower Gneiss Unit (UGU/LGU) attribution and the relationship between metamorphic and magmatic rocks are uncertain. This hinders both our understanding of the geodynamic processes that led to the construction of the Variscan orogenic belt, and a precise assessment of the deep geothermal potential of this high-heat flow area. Our field investigations document a metamorphic gradient with, from South to North, micaschists and paragneiss with a gently, dominantly southward–dipping foliation grading into migmatites that display a steeper foliation. A maximum late Ediacaran deposition age of sedimentary protoliths is determined from LA-ICPMS U–Pb dates of the youngest detrital zircon populations that range from 588.9 ± 7.1 to 571.8 ± 8.2 Ma. Equilibrium phase diagrams calculated for selected samples document a metamorphic gradient from 2.3– 5.3 kbar, and 570°–660°C, characterizing a mid- to low pressure-high temperature event dated from 357.6 ± 1.5 to 342.2 ± 4.6 Ma by LA-ICP-MS U–Pb analyses of metamorphic monazite. The contact between the metasedimentary rocks and migmatites is crosscut by peraluminous, cordierite-biotite-bearing Claveix and Gelles granitic plutons dated at 338.0 ± 7.3 Ma and 323.3 ± 9.7 Ma, respectively by U–Pb on zircon. The distribution of U–Pb dates and Lu–Hf isotopic compositions of detrital zircon in metamorphic rocks; the absence of HP mineral relics; the age of HT metamorphism of ca. 357–345 Ma; and the lack of a major mylonitic tectonic contact, which would typify the base of UGU, collectively support that the exposed crust of the Pontgibaud area corresponds to LGU metamorphic rocks. Moreover, the mineralogy, bulk chemistry and zircon Lu–Hf isotopic composition of the granites and migmatites are consistent with an origin by partial melting of LGU metasedimentary rocks. These data show that the Pontgibaud area exposes a section along a Carboniferous MP-LP/HT metamorphic gradient from micaschists to migmatites. Genesis and extraction of a large volume of granitic magma require higher temperatures (>800 °C) that were not reached by the exposed rocks. Accordingly, we propose that the local mid- and lower crustal levels are made of rocks with a similar protolith as those exposed at the surface, but affected by higher metamorphic grade and magma extraction.
Seyed Poorya Mirfallah Lialestani, David Parcerisa, Mahjoub Himi
et al.
Effective categorization of geothermal resources is essential for strategic and sustainable energy development. Despite the considerable geothermal potential in Spain, utilization remains limited, underscoring the need for advanced and practical assessment methods. This study proposes a structured framework for geothermal resource classification in Catalonia, based on a constructed matrix of features that integrates subsurface temperature, geothermal gradient, and thermal conductivity. The matrix enables resource clustering into potential classes, improving interpretability and regional assessment. The analysis employed predictions from a pretrained hybrid artificial intelligence model optimized using a modified Bat algorithm. At depths between 50 and 150 m, a 20–30% increase in temperature leads to a 30–50% rise in geothermal potential. Approximately 11.5% of sites exhibit high potential and 28.2% moderate potential, indicating the reliability of the adopted framework for geothermal energy source site prioritization. The proposed matrix offers a scalable tool for geothermal evaluation, minimizing exploration risk and supporting sustainable energy planning across diverse geological settings.
Eleanora I. Robbins, Mark R. Stanton, Cheryl D. Young
At depth in an abandoned tunnel of the White Pine Copper Mine, green films of the Cu-OH-Cl minerals atacamite and paratacamite were found on standing pools of brine. Some pools were also coated with a thin layer of petroleum. Green films of atacamite were composed of individual blebs that averaged 20 μm in diameter and enclosed mixed colonies of Gram-negative, short rod-shaped, and sheathed filamentous bacteria. Carbon δ<sup>13</sup>C values in the atacamite–paratacamite mixtures reflect the isotopic values of bacteria and minor amounts of petroleum mixed with the minerals. Heterotrophic bacteria are interpreted to be using petroleum as a carbon source and may be catalyzing the precipitation of the copper hydroxy chloride minerals or acting as a template.
Mining industry generates a significant amount of waste including waste rock and tailings. The disposal of mine tailings has environmental impacts, such as the releasing of heavy metals to surface and underground waters. Therefore, adequate rehabilitation of mining waste storage facilities is essential. Abandoned tailings ponds may contain significant amounts of valuable minerals, including critical raw materials, and offer opportunities as secondary mineral resources. In this study geochemical and mineralogical characterization were made for the diverse mine tailings of the Rautuvaara tailings pond which was the final disposal site for different ore deposits. The samples were collected from two different locations in the tailings pond, preconcentrated and analysed with several methods including PSA, XRD, FE-SEM, EPMA, pXRF, WD-XRF and AAS. The geochemical results indicate substantially elevated Cu, As, Ni and Zn concentrations in the tailings. Mineralogical investigations revealed that the tailings contain valuable minerals such as gold, cobaltite, and W-bearing rutile. The last could be used as an indicator mineral in tailings classification and possibly also in future ore exploration. The study of secondary mineralogy revealed that the most weathered top layers of the tailings show secondary alteration rims on the surfaces of mineral particles, and the enrichment of As and Ni in the Fe- and Mn-oxide minerals.
This is a paper in the field of process mineralogy. Daqiao gold mine is a super-large gold mine discovered in the Qinling region,but in the process of mining primary ore, it is found that the recovery rate of gold is very low by using the traditional beneficiation process, so the refractory pre-deposit is determined, this paper aims to investigate the occurrence state and refractory factors of gold in the deposit. Through microscopic identification, SEM, EPMA, and chemical analysis, combined with mineral processing tests, it is found that gold mainly exists in siliceous breccia in the form of natural gold and silver gold. The granularity of gold and gold-bearing minerals is very small, so that in the process of beneficiation,the sandal can not be dissociated to a high degree under the condition of very fine grinding granularity, which is the main reason that restricts the beneficiability of the ore deposit, it is also found that the ore contains more carbon, which is another reason restricting the ore beneficiability.
Adrian R. Muxworthy, Adrian R. Muxworthy, Jack N. Turney
et al.
High-temperature susceptibility (HT-χ) data are routinely measured in Earth, planetary, and environmental sciences to rapidly identify the magnetic mineralogy of natural systems. The interpretation of such data can be complicated. Whilst some minerals are relatively unaltered by heating and are easy to identify through their Curie or Néel temperature, other common magnetic phases, e.g., iron sulphides, are very unstable to heating. This makes HT-χ interpretation challenging, especially in multi-mineralogical samples. Here, we report a review of the HT-χ data measured primarily at Imperial College London of common magnetic minerals found in natural samples. We show examples of “near pure” natural samples, in addition to examples of interpretation of multi-phase HT-χ data. We hope that this paper will act be the first reference paper for HT-χ data interpretation.
The current study is an assessment of the Al-Tawsseea Cement Plant, located in the northwest of Iraq, Nineveh. This plant produces Ordinary Portland Cement grade 42.5R according to the I.Q.S No(5)/2019. Ordinary Portland Cement was chosen to determine the mineralogy using X-Ray Diffraction and Scanning Electron Microscope before and after hydration. Physical tests were carried out such as the Fineness Test (Blain) ( 331.4) M2/Kg, Soundness Test (Autoclave) 0.1% Compressive Strength Test (2 Days 22.35 N/mm2 and after 28 Days 47.81 N/mm2) and Setting Time Test (Initial 150 Min and Final 3:10 Hours) and all the physical tests are within the requirements of limits according to I.Q.S No(5)/2019. XRD analyses revealed that the studied cement is composed of alite, belite, ferrite, and aluminate which indicate good burning and cooling processes, while after hydration the paste is composed of CSH, CH, and Ettringite. The Scaning Electron Microscope showed that the studied Ordinary Portland Cement microstructure, characterized by an intensive intergrowth of hypidiomorphic crystals and belite (spherical to oval shape) is less but bigger than alite. After hydration, the microstructure became dense and calcium-silicate hydrate (C-S-H ) formed a lathe-like shape fill the pores of the cement paste and gave the paste hardness and good compressive strength. The pore diameters in studied Ordinary Portland Cement are ranging from 9.9 to more than 15.9 µm. They look like circular or irregular shape and are randomly distributed which decrease the density, and compressive strength of the paste. According to the results of the physical test and mineralogy microstructure, we can say that it is possible to raise the grade of Ordinary Portland Cement of the Al-Tawseea Cement Plant ( 42.5R) by increasing the proportion of calcium in the raw materials mixture within the specification. This will lead to an increase in the value of LSF and the C3S which is responsible for increasing hardness or compressive strength.
Mohammad Robel Molla, Most. Hosney Ara Begum, Syed Farid Uddin Farhad
et al.
Herein, paper mill waste sludge (PMS) from two different sources has been investigated to extract calcium hydroxide, Ca(OH)2 by a facile and inexpensive extraction process. PMS samples, collected from local paper mill plants of Bangladesh, were the main precursors wherein HCl and NaOH were used for chemical treatment. The as-synthesized products were analysed by a variety of characterization tools including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) elemental analyses. Our studies confirm that the extracted product contains Ca(OH)2 as a major content, albeit it also includes CaCO3 phase owing to the inescapable carbonation process from the surrounding environment. The particle size of the synthesized products is in the range of 450–500 nm estimated from SEM micrographs. The crystallite domain size of the same estimated from XRD analyses and was found to be approximately 47 and 31 nm respectively for product-A and product-B considering major (101) Bragg peak of Ca(OH)2. The yield percentage of the isolated products is about 65% for samples collected from both sources.
Md Abdus Salam, Md Abdus Salam, Thauhidul Islam
et al.
Metal hydrides are very much reported as a potential safe option for high-density hydrogen storage materials. A combined system of proton-exchange membrane hydrogen fuel cell (PEMFC) and metal hydride (MH) tanks is designed to investigate their characteristics and performances as hydrogen storage and stable power supply system. An AB5-type (LaCe)Ni5 material containing three MH tanks is selected for investigation. Endothermic dehydrogenation of metal hydride controls the hydrogen evolution rates during a discharging period, which reduces the risk of accidents. The MH tank charged at a 20°C water bath sustains and supplies hydrogen for a longer time of 240 min. The performances of the MH tank at a water bath of 20°C and 10-bar conditions correspond to the optimum condition of hydrogen storage at the MH tank of Pragma Industries. The performances of the combined system were investigated in different working conditions. The system sustains and supplies hydrogen to PEMFC for 240, 160, 130, and 110 min for the working loads of 250, 500, 1,000, and 2,000 W, accordingly. It is concluded that hydrogen consumption frequency increases for higher load demand.
Thomas Schirmer, Michael Wahl, Wolfgang Bock
et al.
The recovery of technically important elements like lithium from slag of pyrometallurgical recycling of lithium traction batteries will be very important in future due to the expected increasing demand of this element with the upcoming world-wide implementation of electro mobility. Therefore, the investigation of possibilities to recover lithium from pyrometallurgical slag from the recycling of lithium traction batteries is mandatory. In this context, the EnAM (engineered artificial mineral) approach is very promising. Solidified melt of synthetic recycling slag with the compounds Li<sub>2</sub>O-MgO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-CaO-MnO contains various Li-bearing phases including spinel solid solution, Li-aluminate and eucryptite-like Li-alumosilicate. Most probably, the Ca-alumosilicate matrix (melilite-like solid solution) incorporates lithium as well. These compounds can be determined and calculated to an acceptable approximation with electron probe microanalysis (EPMA). Nevertheless, an adequate precise measurement of lithium is virtually impossible due to the extremely low fluorescence yield and long wavelength of Li Kα. Secondary mass spectrometry (SIMS) can be used to fill this gap in the analytical assessment of the slag. Therefore, the combination of these two analytical methods can distinctively improve the mineralogical and chemical characterization of lithium-containing solidified (slag) melt.
Tlotlo Solomon Gabasiane, Gwiranai Danha, Tirivaviri A. Mamvura
et al.
Copper slag is generated when copper and nickel ores are recovered from their parent ores using a pyrometallurgical process, and these ores usually contain other elements which include iron, cobalt, silica, and alumina. Slag is a major problem in the metallurgical industries as it is dumped into heaps which have accumulated into millions of tons over the years. Moreover, they pose a danger to the environment as they occupy vacant land (space problems). Over the past few years, studies have been conducted to investigate the copper slag-producing outlets to learn their behavior, as well as properties of slag, to have the knowledge of how to better reuse and recycle copper slag. This review article provides the environmental and socioeconomic impacts of slag, as well as a characterization of copper slag, with the aim of reusing and recycling the slag to benefit the environment and economy. Recycling methods are considered an attractive technological pathway for reducing waste and greenhouse gas emissions, as well as promoting the concept of circular economy through the utilization of waste. These metal elements have value depending on their characteristics; hence, copper slag is considered as a secondary source of valuable metals. Some of the pyrometallurgical and hydrometallurgical processes to consider are physical separation, magnetic separation, flotation, leaching, and direct reduction roasting of iron (DRI)<b>.</b> Some of the possible metals that can be recovered from the copper slag include Cu, Fe, Ni, Co, and Ag (precious metals).
I. V. Ashchepkov, A. S. Ivanov, S. I. Kostrovitsky
et al.
We have studied variations in the structure and composition of minerals from the pipes of the Yakutian kimberlite province (YKP) in different mantle terranes of the Siberian craton. The study was based on an extensive database, including the microprobe analysis datasets consolidated by IGM, IG, IEC and IGDNM SB RAS and ALROSA and geochemical analysis of minerals performed by LA‐ICP‐MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry). The reconstruction shows layering under the tubes, including 6–7 slab that were probably formed due to subduction; the slabs are separated by pyroxenitic, eclogitic and metasomatic layers and dunite lenses. Transects and mantle profiles across kimberlite fields are constructed. Within the limits of the revealed tectonic terranes, we assume a collage of microplates formed in the early – middle Archean. Extended submeridional structures of the tectonic terranes are not always confirmed at the mantle level. Beneath the Anabar and Aldan shields, the mantle sections show more coarse layers and 3–4 large horizons of dunites with garnet and pyroxene nests separated by ilmenite‐ phlogopite metasomatites and pyroxenites. Terranes representing the suture zones between the protocratons (e.g. Khapchan) are often saturated with eclogites and pyroxenites that may occur as leghthy ascending bodies of magmatic eclogites penetrating through the mantle lithosphere structure (ML). A nearly ubiquitous pyroxenite layer at the level of 3.5–4.5 GPa formed probably in the early Archean with a high heat flux during melting of eclogites and was subsequently traced by plume melts. Within the early Archean protocratons – granite‐greenstone terranes (Tungus, Markha, Berekta, and Sharyzhalgai, ~3.8–3.0 Gyr [Gladkochub et al., 2019], the mantle lithosphere is less depleted and largely metasomatized. The ML structure of the Daldyn and Magan granulite‐orthogneiss terranes is layered with folding revealed in the north‐to‐south sections from the Udachnaya pipe to the Krasnopresnenskaya pipe, which is less pronounced in the latitudinal direction. From the Daldyn field to the Alakit field, there is an increase in the degree of metasomatism, and higher alkalinity of pyroxenes and larger amounts of phlogopite are noted. The most productive Aikhal and Yubileinaya pipes are confined to a dunite core, which is accompanied by a change in the specialization of high‐charge elements Ta‐Nb to Zr‐Hf. Within the limits of the Magan terrane, the thin‐layer structure of the middle and upper parts of the craton keel is replaced with a sharply depleted productive horizon at its base. The mantle of the granite‐greenstone Markha terrrein comprises eclogite (often pelitic) horizons, which suggests subduction of the continental lithosphere or sediments. In the central and northern parts of the Siberian craton, most structures in the mantle are sinking to the west at small angles. The geochemistry features of garnets and pyroxenes from various mantle terranes are considered in detail.
In Indonesia, gold is commonly mined from porphyry, epithermal and skarn type deposits that are commonly found in volcanic/magmatic belts. However, were recently numerous gold prospects discovered in association with metamorphic rocks. This paper is intended to describe an alteration and ore mineralogy hosted by metamorphic rocks at Rumbia mountains, Bombana regency, Southeast Sulawesi province, Indonesia. The study area is found the placer and primary gold hosted by metamorphic rocks. The placer gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). This study is conducted in three stages, three stages including desk study, field work and laboratory analysis. Desk study mainly covers literature reviews. Field work includes mapping of surface geology, alteration and ore mineralization as well as sampling of representative rocks types, altered rocks and gold-bearing veins. Laboratory analysis includes the petrologic observation of handspecimen samples, petrographic analysis of the thin section and ore microscopy for polished section, XRD (X-ray diffraction), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), ICP-MS (Inductively Coupled Plasma Emission Mass Spectrometry and FA/AAS (Fire Assay/Atomic Absorbtion Spectophotometry) analysis. The results shows that the alteration characteristics of hydrothermal gold deposits in Mendoke and Rumbia mountain consist of 3 (three) alterations namely sericitic, argillic dan propylitic. Characteristics of mineralization hydrothermal gold deposits in the research area are generally p related to gold-bearing quartz veins/veinlets consist of chalcopyrite, pyrite, chrysocolla, covellite, cinnabar, magnetite, hematite and goetite in rocks categorized into greenschist facies. There are three generations of veins identified including the first is parallel to the foliations, the second crosscut the first generation of veins/foliations, and the third is of laminated deformed quartz+calcite veins at the late stage. The quartz veins commonly deformed, segmented, massive, laminated, irregular, brecciated, and occasionally sigmoidal. The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18,4000 at found in third generation veins which are laminated quartz±calcite in argillic alteration. ppm. The protoliths of metamorphic rocks in Rumbia Mountain, which comes from sedimentary rocks, spesifically pelitic rocks and graywacke. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposits type. The orogenic gold deposit is one of the new targets for exploration in Indonesia.
Alberto Hernández-Flores, George Agyei, Arturo Luis Rojas-Purón
Se realizó el análisis fraccional al intervalo granulométrico -2,0+0,074mm de una muestra del yacimiento Punta Gorda, atendiendo a las propiedades físicas de diámetro y densidad de las partículas. Mediante la combinación del análisis de cribado y de la separación de las fracciones de densidad con el empleo de diferentes medios densos se obtiene la función bidimensional de distribución, por el grosor o diámetro y por la densidad, y a través del análisis químico se determina la función experimental. Se realiza la evaluación del beneficio con el empleo del modelo Teoría de separación y se obtienen los parámetros tecnológicos. Como resultado fundamental se logra un concentrado con la separación de la mayor cantidad del magnesio y aluminio de 94,89% y 91,15%, respectivamente. Esto permite pronosticar un mejoramiento en la calidad y estabilidad de la mena de alimentación al proceso extractivo y diversificar el uso del recursos.
Somayeh Momeni, Seyed Vahid Shahrokhi, Peyman Afzal
et al.
Fraktal yöntemler, sığ ve derin mineralizasyon zonlarının sınırlarının
birbirinden daha hassas bir şekilde ayrılması açısından oldukça etkili
yöntemler olarak kabul edilmektedir. Bu araştırmada, KB İran’da bulunan Khoy
1:100.000 ölçekli jeoloji haritası içinde, Cr, Co ve Ni gibi elementleri
açısından umutlu olabilecek alanları saptamak amacıyla konsantrasyon-numara
(C-N) ve konsantrasyon-alan (C-A) fractal yöntemler uygulanmıştır. Elementler
üzerinde factor analizi uygulanmış olup her iki fractal yöntem, elementler ile
ilişkili faktörler izole edilerek çalışılmıştır. Ekstrem anomalilerin güncel
jeolojik konumları araştırılmış olup sonuçlar karşılaştırıldığında bunların çok
yakın ilişki sundukları ve çakıştıkları gözlenmiştir. Sunulan model sonuçlarına
bakıldığında, incelenen çoğu elementin, paftanın merkez ve GB kesimlerinde
kaldıkları anlaşılmıştır. Litoloji açısından bakıldığında ise, bu alanlar
serpantinitin harzburjit ve dünit gibi ultramafik kesimlerine karşılık gelmekte
olup aynı zamanda Cr mineralizasyonu açısından yüksek olasılıklı alanları
göstermektedir. Ulaşılan sonuçlar aynı zamanda faktör analizi ile
doğrulanmıştır. Bu ise, bu elementlerin faktör akümülasyonunun her bir
elementinki ile tam olarak aynı olduğu anlamına gelmektedir.