GMPV4.2 | Critical and strategic raw materials for a sustainable development: ore deposits, new resources and recovery of mine wastes
EDI
Critical and strategic raw materials for a sustainable development: ore deposits, new resources and recovery of mine wastes
Convener: Micol Bussolesi | Co-conveners: Giovanni Grieco, Alessandro Cavallo, Shenghong Yang, Evangelos Tzamos
Orals
| Mon, 24 Apr, 16:15–17:55 (CEST)
 
Room -2.91
Posters on site
| Attendance Mon, 24 Apr, 14:00–15:45 (CEST)
 
Hall X2
Posters virtual
| Attendance Mon, 24 Apr, 14:00–15:45 (CEST)
 
vHall GMPV/G/GD/SM
Orals |
Mon, 16:15
Mon, 14:00
Mon, 14:00
In a scenario of growing supply risk and economic vulnerability, the interest in critical and strategic raw materials has increased, leading to enhancing the exploration of previously subeconomic deposits and the re-evaluation of abandoned mines and mining dumps.
Within the present-day circular economy paradigm, this offers the opportunity to integrate the georesources and environmental studies, aiming to build up a sustainable society.
This session will focus on, but is not limited to, contributions in the fields of mineralogy, petrography, structural geology and geochemistry of critical and strategic raw materials ore deposits, including active and abandoned mining sites. Contributions on the recovery of resources from mining dumps and the environmental assessment and remediation are also welcome.

Orals: Mon, 24 Apr | Room -2.91

Chairpersons: Micol Bussolesi, Alessandro Cavallo, Giovanni Grieco
16:15–16:25
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EGU23-1060
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On-site presentation
José Maria González-Jiménez, Claudio Marchesi, Lola Yesares, Fernando Gervilla, Cristina Villanova, and Joaquin Proenza

The Ronda ultramafic massif constitutes the Earth’s largest outcrop of peridotites (~ 300 km2) of the subcontinental lithospheric mantle (SCLM). This massif is located in the westernmost part of the Málaga province in SW Spain, and mainly consists of peridotites (lherzolites and harzburgites with lesser amounts of dunites) and mafic pyroxenite layers (usually <10 %). These rocks are arranged in a petrologic and geochemical zoning consisting, from the top to the bottom of the mantle section, of the following domains: (1) spinel (±garnet) tectonite corresponding to the exhumed SCLM roots, (2) granular peridotite formed by thermal erosion of pre-existing spinel (±garnet) tectonite due to upwelling of the asthenosphere during unroofing, and (3) plagioclase tectonite corresponding to shear zones originated shortly before or contemporaneously to the crustal emplacement. The rocks forming these three domains exhibit contrasting degrees of fertility in a wide suite of elements, offering an unequal opportunity to evaluate the impact that different bedrocks have for the distribution of High-Tech Critical Metals in soils.

We performed bulk-rock analyses of around 70 samples from 10 soil profiles above peridotites from the three aforementioned petrological domains. Regardless of the original bedrock, all the analyzed soils show a common trend of progressive enrichment of Fe2O3 and Al2O3 and depletion of MgO from bedrock to the atop of the profile. Minor elements such as MnO, TiO2, Na2O and K2O overall increase from bottom to top, whereas SiO2 remains generally unchanged. Interestingly, there is positive correlations between Fe2O3 and MnO as well as other transition metals such as Cr (up to ~9000 pm),  Co (up to 310 ppm), V (up to 181 ppm), Zn (up to 136 ppm) and Sc (up to 38 ppm). A general increasing of total REE (up to ~20 ppm) is also observed in most profiles with a significant enrichment of LREE over HREE.

How to cite: González-Jiménez, J. M., Marchesi, C., Yesares, L., Gervilla, F., Villanova, C., and Proenza, J.: Distribution of High-Tech Critical Metals in soils from the Ronda Ultramafic Massif (SW Spain), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1060, https://doi.org/10.5194/egusphere-egu23-1060, 2023.

16:25–16:35
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EGU23-3728
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ECS
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On-site presentation
Mizuki Ishida, Kentaro Nakamura, Hikaru Iwamori, Takahiro Hosono, and Yasuhiro Kato

Epithermal deposits are formed in shallow (< 1 km) crustal environments by precipitation of ore minerals from hydrothermal fluids, associated with magmatic activities. Epithermal deposits are important sources of gold and associated critical metals (e.g., Ag, Bi, Te) used in high-tech industry (e.g., [1]). However, little is known about the controls on their deposit sizes, which range more than two orders of magnitude (<1 to >100 t of contained Au). Since deposit size is a major determining parameter for mine profitability, estimating the governing processes for metal endowment should have important implications for exploration. Here we show that the giant (> 200 t Au) Hishikari epithermal gold deposit in south Kyushu, Japan, is likely to have formed by combination of the following three trans-crustal geological processes: (i) oxidized source mantle of primary magmas, (ii) differentiation of ore-forming magmas without voluminous sulfide saturation and (iii) structural focusing of exsolved ore-forming fluids. These geological processes were recognized by (i) high V/Yb ratio (> 160) of high MgO regional volcanic rocks which reflect the oxidizing [2], high sulfur and gold solubility condition during mantle melting, (ii) minor contribution from reducing crustal rocks [3] and late magnetite saturation which maintained a relatively high fO2 as well as high sulfur solubility until later stage of differentiation, and (iii) basement uplift or depression detected by geophysical surveys [4] which created effective conduits for hydrothermal fluids. In contrast, representative districts in Japan with previous extensive exploration campaigns (Toyoha, Nansatsu, Iriki, Masaki) failed to meet more than one of the above criteria, which likely explain the smaller or lack of gold mineralization in these districts. Our findings demonstrate the importance of optimally aligned trans-crustal geological processes in the formation of giant gold deposits and the potential utility of the geochemistry of regional volcanic rocks in early stages of epithermal gold exploration.

[1] Goldfarb, R. J., et al. (2016). Reviews in Economic Geology 18: 217-244.
[2] Laubier, M., et al. (2014). Earth and Planetary Science Letters 392: 265-278.
[3] Hosono, T., et al. (2003). Chemical Geology 201: 19-36.
[4] Izawa, E., et al. (1990). Journal of Geochemical Exploration 36: 1-56.

 

How to cite: Ishida, M., Nakamura, K., Iwamori, H., Hosono, T., and Kato, Y.: Importance of trans-crustal geological processes in understanding the genesis of giant epithermal gold deposits: The case of Hishikari deposit, Japan, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3728, https://doi.org/10.5194/egusphere-egu23-3728, 2023.

16:35–16:45
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EGU23-219
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ECS
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On-site presentation
Nema Gueimar, Mouhamadou Idriss Abdellahi, and Hanafi Benali

Archean and Paleoproterozoic rocks of the Reguibat shied contain main potential Mauritania's mineral deposits. The western Archean terrane includes significant iron deposits in the Tiris and Tasiast gold deposits, while the eastern Birimian rocks have proved mining indices of gold and uranium. Located on the northeastern edge of the Reguibat shield,  the study area of NSOUR, and OUED EL MA prospects represent a complex shear zone of favorable gold mineralization. Through our drill cores and soil samples analysis, the gold mineralization is proved to be hosted within a series of nearly parallel, steeply dipping quartz veins. Our chemical and geophysical results demonstrate a set of indicators of important tonnage and grade of gold in the quartz veins. Results of chemical analyses obtained on all the analyzed samples show gold concentration between 0.33 to 2.12 g/m. Importantly, in the southern part of the prospect, 62% of the wells samples recorded an interception of at least one gram per tonne over more than one meter. Statistical evaluation of these data established large first-level zones delineating areas favorable to gold resources and important potential gold accumulation in these areas. Such first-level identifications nonetheless make it possible to roughly define the potential zones for orogenic gold deposits and encourage the continuation and the intensification of the works of exploration that favor discovery in these Precambrian rocks.

How to cite: Gueimar, N., Abdellahi, M. I., and Benali, H.: Geostatistical study of the gold mineralization of the Nsour region. Reguibat shield, Northern Mauritania, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-219, https://doi.org/10.5194/egusphere-egu23-219, 2023.

16:45–16:55
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EGU23-1835
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On-site presentation
Bakhtiar Nurtaev and Dilshoda Kurbanova

The geologic setting of the Kurama mining district is controlled by its assignment to the structures of the eastern part of the extended Beltau–Kurama volcanoplutonic belt in the Middle Tien Shan. This district of Paleozoic age exemplify unique deposits with perfectly preserved characteristic features of Cu-Au-Mo porphyry, epithermal Au–Ag–Te, Ag–Pb–Zn, as well as numerous occurrences of Au, Ag, Cu, Pb, Zn, Bi, and Sn mineralization. Intense magmatic processes occurred in this region throughout the whole Paleozoic, reaching a maximum at its end. The very high concentration of ore occurrences is related to the confinement of the region to the intersection of deep tectonic structures. Another unique feature of this region is that it is a rare example of paleovolcanic areas with well preserved epithermal deposits of Late Paleozoic age. Here we compile published and some new geodynamic, mineralogical and geochemical data, including regional geological features and ore characteristics, sequence of the mineral formation, main mineral assemblages and discuss factors controlling the enrichment mechanism of huge amounts of Cu, Au, Mo, Ag, Re, Pd, Pb, Zn and other elements in the Almalyk ore-field through field and laboratory investigation. We will present summary of the geological, geochronologic and geochemical characteristics of porphyry, scarn and epithermal gold-silver deposits to establish a series of discriminant indicators, which can provide reference for future research on the genetic connection of different deposits in the porphyry copper system. The occurrence of mafic dikes, post-dating the porphyry mineralization and high Re concentrations in the molybdenite may be attributed to a direct involvement of mantle in an arc-subduction environment. But it is becoming more obvious that the problem of sources of ore and rare elements forming cannot be solved only by their introduction with magma. In many specific examples of the formation of the largest and unique concentrations, their confinement to the underlying and enclosing sedimentary rocks, sharply enriched in valuable impurities, is observed. These rocks include organogenic dolomites or dolomitic limestones. During intrusion of igneous bodies, the presence of reactive carbonate rocks (limestone, dolomite, marl) led to the formation of gold-bearing Au-Cu- and Pb-Zn-skarn deposits. The integrated results of this study are used to discuss the metallogenic processes that formed the unique Cu-Au-Mo porphyry, epithermal Au–Ag–Te, Ag–Pb–Zn deposits in the largest porphyry copper-polimetallic ore Almalyk district in the Central Asian Orogenic Belt.

How to cite: Nurtaev, B. and Kurbanova, D.: Metallogenic processes that formed the Cu-Au-Mo porphyry and epithermal Au-Ag-Te deposits in the Almalyk ore district, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1835, https://doi.org/10.5194/egusphere-egu23-1835, 2023.

16:55–17:05
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EGU23-7021
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ECS
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Virtual presentation
Ignazio Scano, Antonio Attardi, Alfredo Idini, Alessandro Murroni, Francesca Zara, and Stefano Naitza

In recent years mineral sources of Critical Raw Materials (CRMs), whose supply is strategic and irreplaceable in many technological and industrial applications, have become the subject of growing interest throughout Europe. An excellent example is the Silius vein system (SE Sardinia), in which the mining activities, after several years of standby, are going to be resumed to exploit fluorite, galena and LREE minerals. This world-class deposit (2.2 Mt of proven reserves) consists of two main parallel, steeply dipping, ENE-WSW to NE-SW directed veins which coalesce at depth, hosted in Middle Ordovician metavolcanites, Upper Ordovician metasediments and Silurian black shales belonging to the Variscan  Nappe Zone of SE Sardinia. The vein filling displays dominantly banded textures with abundant fluorite, quartz, calcite, galena, barite, and accessory base-metal sulfides (sphalerite, chalcopyrite and pyrite-marcasite), LREE carbonate (synchisite-Ce) and xenotime-Y. Sulfide contents in the ore increase downward. Knowledge about the trace elements content of sulfides in the deposits is still scarce, thus new underground surveys and samplings have been performed in three different levels of the mine. In samples collected from the deepest level (level 100 m a.s.l., Muscadroxiu sector), tiny inclusions of Ni-Co minerals have been found for the first time ever by optical microscopy (reflected light) and SEM-EDS analyses. They consist of very complex intergrowths dispersed in chalcopyrite and the quartz gangue, containing various associations of Ni-Co-Fe arsenides and sulfarsenides such as nickeline, rammelsbergite, gersdorffite, cobaltite and arsenopyrite. Remarkably, this assemblage is very similar to that found in the shallower parts of the nearby “Sarrabus Silver Lode”, a similar, regional-scale vein system exploited in the past for silver. Thus, it may be speculated that it not only could be a general indication of possible Ni-Co enrichments below the 100 level of the mine, but also an exploration tool and a proxy of possible Ag enrichments of the ore at depth. Moreover, the Ni-Co assemblages and LREE minerals found in Silius are similar to those found in the polymetallic (Ni-Co-As-Ag-Bi) veins of Southern Arburèse district (SW Sardinia), the five-element branch of the Montevecchio vein system, in the past a major Pb-Zn source in Italy. In addition to partly similar mineral assemblages, the Silius and Arburèse vein systems share a common derivation from low-temperature and high-saline fluids, supporting their attribution to the unconformity-related group of five-element and fluorite-barite deposits well-known throughout central and western Europe (Erzgebirge, Odenwald, Schwarzwald, French Central Massif, Catalonian Coastal Ranges, Pennidic Alps, etc.). These deposits have been collectively connected to metallogenic events associated with the Late Paleozoic-Mesozoic breakup of the supercontinent Pangea, so Silius, the Arburèse and other similar Sardinian deposits could be related to this regional-scale event. In conclusion, the Silius vein system is a key area to understand the regional events that occurred after the Variscan orogeny in Sardinia; the deposit may represent a relevant source of CRMs and metals in Italy, where besides fluorite, base-metal sulfides and LREE, some concentrations of Ni-Co and, possibly, Ag minerals might be present at depth.

How to cite: Scano, I., Attardi, A., Idini, A., Murroni, A., Zara, F., and Naitza, S.: From a fluorite vein system to a five-element-type polymetallic vein system? The first evidence of Ni-Co minerals from the world-class, CRMs-bearing Silius deposit (SE Sardinia, Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7021, https://doi.org/10.5194/egusphere-egu23-7021, 2023.

17:05–17:15
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EGU23-8951
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ECS
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Virtual presentation
Mohamed Idbaroud, Mohammed Bouabdellah, Gilles Levresse, El Mostafa Mouguina, Johan Yans, and Lhou Maacha

The Oumjrane copper deposit in eastern Anti-Atlas is one of the top three major copper producers in North Africa with an annual production exceeding 260,000 tons at an average grade of 1.4% Cu. Current inferred resources are estimated at 5 million metric tons grading 1.5% Cu. Host rocks consist of a succession of Ordovician carbonate-free siliciclastic metasediments comprising sandstone- and quartzite-dominated rocks with cherty beds and phosphate nodules, conformably overlain by Silurian organic-rich black-shales. In the mine area, high-grade ores were recovered from open pits and underground workings of three major roughly continuous, subparallel, and steeply dipping vein systems referred to as Bou N’Hass, Bou Kerzia, and Zagora Graben over a strike length exceeding 10 km. The veins extend vertically for as much as 300 m, and their widths vary from ~2 m to ~15 m averaging 4m. The paragenetic sequence comprises two main stages of alteration and related mineralization. The earliest stage, referred to as the main Cu-rich stage I, is economically the most productive consisting of ore-related quartz together with chalcopyrite and reddish to orange apatite (i.e., Ap-1). The later Pb-Zn-Ba-rich stage II consists of variable proportions of galena and sphalerite enclosed in a matrix of barite as the main gangue minerals. Texturally, this stage ends with the development of well-developed green apatite crystals (i.e., Ap-2) up to 12 cm across. In addition to its potential for U–Pb dating, the REE+Y chemistry of the paragenetically well-constrained ore-related apatite (i.e., Ap-1, Ap-2) could provide insights into fluid chemistry, fluid-rock conditions, and fluid-rock interaction processes that prevailed during ore deposition of both ore stages. In this respect, EMPA analyses show that Ap-1 is almost pure hydroxyapatite, (XF=0.198-0.334, XCl=0.001-0.078, XOH=0.642-0.795), whereas Ap-2 is fluorapatite (XF=0.190-0.227, XCl=0.066-0.101, XOH=0.672-0.743). More importantly, LA-ICP-MS analyses indicate that Ap-1 is characterized by ∑REE+Y contents ranging from 962 to 2435 ppm and shows bell-shaped PAAS-normalized patterns with prominent negative Y anomaly Conversely, Ap-2 yields on average the highest ΣREE+Y concentrations at 8473 ppm, and shows negative sloped pattern with no Eu anomaly. The Y/Ho values are variable, but are generally distributed between 15 and 18 for Ap-1, and 23 and 26 for Ap-2. Overall, these geochemical characteristics indicate that there are two temporally distinct mineralizing events. The earlier Zn-rich stage is thought to have occurred in response to hydrothermal circulation of basinal brines and extensive fluid-rock interaction with the phosphate-rich lithologies. Conversely, the late Pb-Zn-Ba stage is linked to mixing between basinal brines and mantle-derived fluids, likely derived from the synchronous Middle Jurassic–Lower Cretaceous alkaline magmatic series. Ongoing U-Pb geochronology of both apatite types is performed to constrain the timing of mineralization and to trace back the ore-forming source(s) and processe(s).

 

How to cite: Idbaroud, M., Bouabdellah, M., Levresse, G., Mouguina, E. M., Yans, J., and Maacha, L.: Two mineralizing events unraveled by trace element geochemistry of ore-related apatite from the polymetallic Cu-(Pb-Zn-Ba) Oumjrane deposit (Eastern Anti-Atlas, Morocco), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8951, https://doi.org/10.5194/egusphere-egu23-8951, 2023.

17:15–17:25
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EGU23-12079
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ECS
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On-site presentation
Mauro Bongiovanni, Tobias Fusswinkel, and Michael Marks

The recent need of a green-energy transition has sparked even more interest on critical elements such as tungsten and tin, whose genesis in ore deposits is linked to fluids exsolving from granitic plutons, but some mechanisms of formation remain unclear. Most authors in the past have proposed the mixing with meteoric, metamorphic or basinal fluids to be critical, while others believe that these deposits can form by simple cooling of magmatic fluids.

Given the modern advances in analytical techniques, it is nowadays possible to characterize fluid inclusions in-situ also for trace elements such as bromine and especially iodine with the LA-ICP-MS. This study aims to apply a novel technique of measuring Br/Cl and I/Cl in individual fluid inclusions and bring some new insights on the Sn-W ore deposits genesis from a different perspective. In fact, halogens are well known to be highly incompatible in most minerals, retaining the fluid source reservoir signature, and to behave conservatively in fluid-rock interaction, therefore they can be regarded as suitable tracers for fluid evolution. These characteristics make heavy halogen studies particularly suitable for tackling the open question on the formation of Sn-W mineralized systems.

The study area is the well-studied Cornubian batholith, in south-west England, which has been extensively mined in the past mostly for tin, copper and tungsten. It consists of 5 types of granites, divided into two main fractionation series, and cross-cut by mineralized veins rich in cassiterite, Cu-sulphides and W-oxides (among others), outcropping mainly in proximity of the contacts with the country rock.

Despite significant mineralogical variation across the samples, representing different stages of the transition from magmatic to hydrothermal environments, halogen ratios are relatively homogeneous, especially under the hydrothermal regime, with magmatic fractionation as the only candidate process for a shift to higher Br/Cl and I/Cl values. On the other hand, alkalis and metals in fluid inclusions display variations of several orders of magnitude, with Li and B peaking in pegmatites and base metals being particularly abundant in the magmatic stage.

These results suggest that even moderate changes in P-T conditions (from granitic stage to low-T mineralisation) do not affect significantly the halogen signature of the evolving fluids in the Cornubian batholith. Additionally, given the linear relation between fluid salinity and alkali/metal content, it can be postulated that meteoric water is the main diluting agent throughout the evolution of the system, as mixing with metamorphic fluids or basinal brines would also significantly change the halogen signatures. 

How to cite: Bongiovanni, M., Fusswinkel, T., and Marks, M.: The signature of heavy halogens across the evolution of a Sn-W-Cu mineralized system: a fluid inclusion study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12079, https://doi.org/10.5194/egusphere-egu23-12079, 2023.

17:25–17:35
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EGU23-402
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ECS
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On-site presentation
Naside Merve Sutcu, Zeynep Doner, Ali Tugcan Unluer, and Mustafa Kumral

Vanadium (V), is primarily used in the production of metal alloys (in addition to high strength low alloy properties) and reinforcing titanium alloys, take notice in the current critical element list by organizations such as the European Union and USGS. There is no detailed study on the exploration of vanadium resources in Turkey. Recently, vanadium can be extracted from several different types of mineral deposits and from fossil fuels. Black shales can be considered as one of the vanadium resources recently. Black shales are fine-grained sedimentary rocks containing not only in organic matter but also in specific trace elements, like V, Mo, Cu, Zn, Ni, Cd, Se, Pb and U.

The study area is located in the Karabük – Kastamonu in Black Sea region of Turkey and primarily consist of Silurian aged black shales. These black shales can be described as a Hercynian continental sliver, which represents the northernmost part of the Western Pontides . This study focuses on revealing the content and major controlling factor of V of Late Silurian-Early Devonian aged black shales in the northwestern Black Sea Region of Turkey. In the end, the depositional model was established. Studied black shales have a wide range of vanadium content, varying from 74 to 400 μg/g. It can be stated that authigenic enrichments in modern suboxic settings, and likely represent the removal of dissolved V as V(IV). V(IV) was adsorped by organic matter. This result is also supported by several redox indicators such as V systematics (V/Sc, V/Ni) as well as ratios of Ni/Co, Th/U, and Mo/Mn. The reducing of V(III), is mainly associated with the excessive H2S accumulation in sediments and bottom waters and strong reducing conditions is also a key factor. In this circumstance, the decoupling mechanism of V changes from surface adsorption to ionic substitution forming solid solution series with Al in clays. In addition, the Al−Fe−Mn discriminant diagram of siliceous rocks, show that the genesis of siliceous rocks are close to the biogenic origin. The moderate positive correlation of V vs. TOC (R2=0.52) crossplot and the lack of correlation of V vs. clay-forming elements (Al2O3, K2O, Na2O, and CaO) mean that the organic matter rather than clay minerals can play a role in V enrichments. Also, it means that water conditions were controlled by elevated organic matter flux and consequent oxygen drawdown. Nevertheless, the discreteness of data in cross-plot diagrams may imply that a portion of the V in the samples occurs in other forms in addition to occurring in relation to organic matter. More detailed investigations are necessary.

Keywords: Vanadium potential; Black shales; Depositional model; Northwestern Black Sea; Turkey

How to cite: Sutcu, N. M., Doner, Z., Unluer, A. T., and Kumral, M.: Vanadium Potentiality of Late Silurian-Early Devonian Black Shales in Northwestern Black Sea Region, Turkey, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-402, https://doi.org/10.5194/egusphere-egu23-402, 2023.

17:35–17:45
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EGU23-3821
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ECS
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On-site presentation
Stuti Mishra and Deo Raj Kaushal

A slurry pipeline is a specially designed pipeline used to transport the tailings, wastes from the mining, ores like iron or coal to long distances. A commercially tested solution for the transport of iron ore slurry over the farthest distances in a pipeline includes various parametric checks. For the slurry to move without any hassle in the pipe maintaining the required velocity, it is important to keep some parameters in the desired limits, the most important of which is the rheological characteristics of the slurry. The rheological characteristics gives us an idea about the viscous properties, stress strain behavior of the iron ore exhibiting in its surrounding. The rheological parameters of the iron ore slurry were measured using a high precision Anton paar RheoloabQC Rheometer. At different concentrations the samples were tested keeping the particle size to be same for all the observations. While the method has been kept the same for the experiments, different rotating tools are used in the rheometer to check the accuracy of the data as well as to draw a comparison on the data obtained from them for each level of concentration. Our study majorly deals with a comparative assessment of the performance of the various rotating tools to study the rheology of the iron ore slurry.

How to cite: Mishra, S. and Kaushal, D. R.: Analyzing the rheological behavior of medium fine iron ore slurry., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3821, https://doi.org/10.5194/egusphere-egu23-3821, 2023.

17:45–17:55
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EGU23-3920
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ECS
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Virtual presentation
Ali Tugcan Unluer and Murat Budakoglu

The carbonatite complexes are famous for being hosts for various critical elements including Rare Metals (REE) Thorium (Th), and Uranium (U). Turkey hosts a number of carbonatite-related Light Rare Earth Element (LREE) deposits such as the Ozvatan nepheline syenite - carbonatite complex in Central Turkey.  The Upper Cretaceous Ozvatan complex is composed of nepheline syenites, multi-stage calcio-carbonatite dikes, and a metasomatic aureole around carbonatite dikes. The carbonatites of the complex are mainly sövites (coarse-grained calcites) with fluorites and relict silicate minerals such as nephelines. The Sövite dikes of the Özvatan complex are mainly enriched in terms of LREE (up to 2134 ppm). La, Ce, and Nd constitute most of the LREE values in Sövites. The repetitive emplacement of carbonatite emplacement also caused a wide alteration zone with euhedral nephelines, secondary K-feldspars, and garnets. The alteration zones around carbonatite dikes were identified as potassic fenites due to the enrichment of K and incompatible elements including REE, Ba, and Sr. The REE values of K- fenites in the study area are similar to sövite dikes and determined up to 1445 ppm. However, the brecciated K-fenites contain significantly higher values (up to 3596 ppm) than carbonatites and non-brecciated K-fenites. Other incompatible elements such as Th, U, and Nb are also enriched in brecciated K-fenite zones. Carbonatite veinlets in K-fenites are also observed, therefore it can be concluded that the brecciation and metasomatism processes are closely related to multistage carbonatite emplacements.

Keywords: Carbonatite, REE- Enrichments, Alkali-Potassic Rocks

How to cite: Unluer, A. T. and Budakoglu, M.: Geochemical Features of Ozvatan (Central Anatolia, Turkey) Carbonatites and Potassic Fenite Zones ., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3920, https://doi.org/10.5194/egusphere-egu23-3920, 2023.

Posters on site: Mon, 24 Apr, 14:00–15:45 | Hall X2

Chairpersons: Micol Bussolesi, Alessandro Cavallo, Evangelos Tzamos
X2.108
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EGU23-748
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ECS
Iphigenia Anagnostopoulos and Soraya Heuss-Aßbichler

Significant amounts of heavy metal-loaded wastewater are produced during the processing and manufacturing of metals. These wastewaters are challenging to treat owing to their chemically complex properties and are considered hazardous, as they are toxic to humans and the environment. The conventional purification method binds the heavy metals into a hydroxide complex, which causes large amounts of voluminous sludge, usually disposed of in landfills. Hence, valuable metals are lost due to dissipation. Recently, waste has received greater attention as a potential metal resource for economic and political reasons. Accordingly, research is carried out to improve wastewater treatment methods to extract metals from wastewater efficiently.

In our work, we apply insights from mineralogy to (1) recover heavy metals from wastewater so they can be recycled and (2) purify the wastewater. We explore the precipitation conditions of metal oxide conditions experimentally and study the effects of parameters such as reaction temperature, alkalization conditions, kinetic effects, and alteration conditions on the metal phases. We find that transformation reactions play a crucial role, and kinetics can, directly and indirectly, control the mineralogy of the precipitated minerals. Based on our findings, we formulated treatment recipes for individual wastewater and constructed an automated pilot facility that enables the treatment. Heavy metal-enriched wastewater from different industries, such as electroplating and chemical catalyst production, is used as sample material. Three elemental wastewater systems (Zn, Au, and Cu) were tested. However, the Cu-enriched electroplating wastewater is multi-element wastewater showing lower concentrations of Zn, Pb, Ni, Cr, and Mn.

Zn could be recovered as ZnO, and Cu-recovery is possible as Cu-ferrite (CuFe2O4), delafossite (CuFeO2), or CuO depending on the addition of Fe to the system. With a two-step process, Au is retrieved as zero-valent Au during the first process step and Fe as magnetite during the second. In the Cu-system a variation of stirring speed resulted in either the formation of brochantite, a Cu-sulfate mineral, or CuO. Alteration of the suspension generally leads to reduced metal concentrations, and limit values for discharge are met for Zn, Pb, Ni, and Cr.

How to cite: Anagnostopoulos, I. and Heuss-Aßbichler, S.: Using a mineralogical approach to recover metals efficiently from wastewater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-748, https://doi.org/10.5194/egusphere-egu23-748, 2023.

X2.109
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EGU23-1910
Alessandro Cavallo

Dimension stones (marbles, granites, and stones) represent, at the EU level, a very important market. Some general characteristics must be faced to guarantee a profitable and sustainable quarrying activity: the variability of the lithotypes; the relatively limited productions of commercial blocks; and the low ratio between the “workable” and the gross volumes extracted, with a consequent huge production of extractive waste (irregular blocks, stone chips and residual sludge), whose management is still a matter of concern. The mining and quarrying industry represented the second most important sector in terms of waste quantities produced in the EU-27 (26.6% or 562 Mt), after Construction and Demolition Waste (36% or 769.32 Mt). The necessity to reduce the use of non-renewable natural resources and, at the same time, to minimize the negative impacts the on environment, has led to an increasingly high interest in recycling for different applications, such as aggregates, fillers, geopolymers and industrial minerals. To maximize profit and sustainability, it is crucial to value reuses with higher added value (e.g., industrial minerals) over those with lower value (e.g., aggregates), while at the same time seeking innovative and/or strategic uses. While it's relatively easy to find reuses for wastes of carbonatic composition (lime, cements, fillers), it is more complex to find applications for quartz-feldspathic materials (granites, gneisses, migmatites). The example proposed in this paper is related to the quarrying districts of Piedmont (northern Italy), which include a wide range of quartz-feldpathic rocks (granites and gneisses such as Serizzo, Beola, Luserna Stone). The recovery of granite waste has been successfully developed for years: after a series of crushing, comminution, and magnetic separation treatments (to remove biotite), a mix of quartz and feldspars, with a low FeO content, is produced from the waste and successfully used in the ceramic industry. The waste from gneisses, having a mineralogical composition comparable to that of granites, could find similar reuse: however, more difficulties are encountered, mainly due to the smaller grain size and metamorphic fabric, which make separation processes more complex (however feasible, apart from a few special and isolated cases). Extensive mineral-petrographic investigations have shown that these waste materials can also be useful in the extraction of critical raw materials, especially rare earth elements (REE). Granites contain monazite (one of the most important REE phosphates), which is concentrated in the predominantly biotitic magnetic waste fraction, while gneisses contain appreciable amounts of allanite (an epidote variety rich in REE). In both cases, it would be possible to concentrate these REE ore minerals by (relatively) simple processes of crushing, comminution, magnetic and gravitative separation, while supplementing and maintaining industrial mineral production (quartz and feldspars).  The feasibility of the processes should be tested in pilot plants, ideally side-by-side with those already existing and operating for the recovery of granite waste. It is imperative to change and update the view (and regulation) of mining and quarrying waste, which can provide important production of industrial minerals and even critical raw materials, fitting perfectly into the (often too abstract) concept of circular economy.

How to cite: Cavallo, A.: Dimension stone industry waste: a new source of industrial minerals and critical raw materials?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1910, https://doi.org/10.5194/egusphere-egu23-1910, 2023.

X2.110
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EGU23-2193
Giljae Yim, Sangwoo Ji, Youngwook Cheong, and Dong-Wan Cho

There are totally 5,396 mines located in South Korea, and 2,033 mines are presently closed or abandoned. According to the current status of mine hazard by mine damage type (2017) of the Korea Mine Rehabilitation and mineral Resources Corporation, mine hazard could be caused by tailings loss in 237 mines. Mining stream/void inside the mines are inevitably formed during resource development, and therefore the appropriate management for the mine stability is continuously needed. Mining filling is regarded as one of the best options since the filling mass acts as a secondary support material that can ensure the stability of the mine void and increase the yielding rate of mining. This study evaluated the suitability of harmless tailings, generated from mine development, as a paste backfill material to secure the stability of mine. The particle size of tailings collected at the tungsten mine used in the study was suitable to be used as a paste backfill materials. The strength of cement solidified using test materials was affected by the content of cement and curing duration of the backfill materials sample. It turned out that above 3.5% the cement content and curing for two weeks were an optimal condition to produce the safe cement. In the Environment Ministry's water pollutant emission acceptance standards (South Korea), the tested backfill materials passed all domestic standards for As, Cd, Cr+6, Pb, Cu, and Hg. The environmental/physical properties of tailings obtained from the results demonstrated that the use the tailings as a paste backfill material to fill the inner space of mines could be considered as a promising option. This evaluation results will contribute to the stabilization of mining enemies and restoration of mine damage in abandoned mine areas through economical and efficient treatment of tailings.

How to cite: Yim, G., Ji, S., Cheong, Y., and Cho, D.-W.: Feasibility evaluation of utilizing mine tailings as a paste backfill material for mine filling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2193, https://doi.org/10.5194/egusphere-egu23-2193, 2023.

X2.111
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EGU23-6220
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ECS
Micol Bussolesi, Alessandro Cavallo, Giovanni Grieco, and Evangelos Tzamos

Antimony is a strategic element, widely used in the production of alloys, halogen-bearing flame retardants and semiconductors. As the main antimony supplier is China, new providers in the EU are necessary in order to decrease its criticality.

The present study aims to evaluate the antimony enrichment of the Pb-Zn-Au carbonate replacement Stratoni deposit, Chalkidiki, Greece. The mineral assemblage comprises galena, sphalerite, pyrite and arsenopyrite ± subordinate phases such as boulangerite, bournonite, chalcopyrite, pyrrhotite and graphite.

Boulangerite (Pb5Sb4S11) is the most abundant Sb phase, and occurs as long acicular crystals within galena, the matrix or massive pyrite. Crystal size ranges between 10 and >100 µm. Bournonite (PbCuSbS3) is less abundant, and occurs associated with boulangerite, included in pyrite as small crystals (<20 µm).

Boulangerite shows Sb contents ranging between 25.64 and 26.45 wt%, whereas bournonite shows Sb contents between 23.37 and 25.23 wt%. Base metal sulfides contain low amounts of Sb: up to 0.44 wt% within pyrite, up to 0.21 wt% within sphalerite and up to 0.28 wt% within galena. Arsenopyrite and chalcopyrite Sb contents are even lower.

The enrichment plant works in three consecutive stages, producing galena, sphalerite and pyrite concentrates. Each stage comprises conditioning, roughing, scavenging and cleaning flotation cells.

Grain size analyses show similar granulometric curves for the concentrates, with uniformity coefficients lower than 3. D90, D50 and D10 are respectively 400, 110 and 45 µm for galena, 127, 60 and 42 µm for sphalerite and 240, 105 and 49 µm for pyrite concentrates.

Whole rock major (XRF) and trace element (ICP-MS) analyses show that most of the antimony, and therefore of boulangerite and bournonite, reports to the galena concentrate. Starting from 1169 ppb in the initial feed Sb is highly enriched in the galena concentrate (20633 ppm), not enriched in the sphalerite concentrate (1170 ppm) and relatively depleted in the pyrite concentrate (334 ppm), making the galena concentrate a suitable candidate for Sb recovery.

The presence of Sb mostly in its own phases opens up the potentiality to recover the metal as a by-product of galena production. The crystal size of boulangerite is large enough to allow separation through flotation. Further tests are necessary in order to evaluate the amount of Sb phases in tiny inclusions within base metal sulfides and Sb enrichment in base metal phases, that can negatively affect the metal recovery.

How to cite: Bussolesi, M., Cavallo, A., Grieco, G., and Tzamos, E.: Critical Raw Materials supply in the EU: the case of Sb-rich Pb-Zn-Au mineralization, Chalkidiki, Greece, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6220, https://doi.org/10.5194/egusphere-egu23-6220, 2023.

X2.112
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EGU23-7468
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ECS
Ali Tugcan Unluer, Murat Budakoglu, Ali Erdem Bakkalbasi, Zeynep Doner, and Huseyin Kocaturk

The Ozvatan carbonatite complex is located on the Eastern Part of the Central Anatolia, Turkey and host considerable Light Rare Earth Elements (LREE) mineralizations. The carbonatites in Ozvatan complex are mostly coarse grained calcio-carbonatites (sövites) with fluorites and minor opaque minerals. The carbonatites were intruded into silica undersaturated nepheline syenites and caused an intense fenitization process. The calcio-carbonatites of the study are were predominantly enriched in terms of La (up to 995 ppm), Ce (up to 1386 ppm) and Nd (up to 211 ppm). Also some of the LILE’s are enriched including Sr (up to 2%) and Ba (up to 0.75) as expected.  The stable δ13CV-PDB  and δ18OV-SMOW values of the Ozvatan carbonatites represent fractional crystallization and hydrothermal alteration trends. The δ13C values (-6.0 – 4.1 ‰) are generally in tune with worldwide carbonatite range. However, it cannot be concluded as a primary ignous carbonatitic melt due to relatively high δ13CV-PDB values. The  δ18O values (13.3 – 49.3 ‰)  are  also high  mostly cauesed by the high intensity hydrothermal activities (fenitization) or the contamination of meta-carbonate basement rocks. Overall, it can be stated that the, carbonatites of the Ozvatan are products of fractionation of a carbonated silicate melt, low temprature metasomatism and crustal contamination.

 

Keywords: Alkaline Magmatism, Carbonatite, Stable isotopes

How to cite: Unluer, A. T., Budakoglu, M., Bakkalbasi, A. E., Doner, Z., and Kocaturk, H.: The Stable Isotopes and Geochemical Investigation of Ozvatan Carbonatites (Central Anatolia, Turkey), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7468, https://doi.org/10.5194/egusphere-egu23-7468, 2023.

X2.113
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EGU23-15202
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ECS
Igor Morais, Maria João Batista, Patricia Represas, Luis Albardeiro, Cátia Prazeres, José Manuel Plastov, João Carlo Sousa, Paulo Bravo, Pedro Sousa, João Carvalho, José Feliciano Rodrigues, Daniel Oliveira, and Domingos Cordeiro

In the SW sector of the Angolan shield occur the Kunene Anorthositic Complex (KAC), one of the most remarkable magmatic anorthositic suites worldwide. The KAC is considered a long-lived magmatic system that operated in the area intermittently during the Mesoproterozoic (1450 ± 2 Ma to 1371 ± 2.5 Ma). Smaller mafic-ultramafic intrusive bodies ranging in composition from dunite to harzbugite, pyroxenite, troctolite and gabbro are located in the KAC periphery (e.g. Epupa, Ombuku, Hamutenha, Oncócua). The Hamutenha body is a 3 km long oriented NW-SE, banded intrusion with internal zonation hosted in the Paleoproterozoic granitic rocks (1970 ± 2 Ma). The internal zone is composed by rocks with ultramafic nature, mostly harzburgites and dunites with diorites in the external zone.

The Hamutenha outcrop has been identified as having great potential to host Cr, Ni and PGE mineralizations. Previous soil geochemistry work, carried on dunitic outcrops (3000 samples) identified high anomalies in Cr (12 500 mg/kg-1), Ni (3100 mg/kg-1) and Co (375 mg/kg-1). The Hamutenha dunites are depleted in platinum-group elements (PGE) although the high Ti content in spinels (15.66 % of TiO2) indicate a parental magma relatively rich in Ti, similar to another intrusions of same type with mineralizations of Fe-Ti-Cr and Pt-Pd sulfides.

In the PLANAGEO project (National Geology Plan of Angola), the National Laboratory of Energy and Geology (Portugal) (LNEG) carried out detailed geochemical and geophysical surveys in the Hamutenha outcrop in order to evaluate the metallogenetic potential. Soil geochemistry showed high contents in Cr (618 mg/kg-1), Co (76 mg/kg-1), Ni (100 mg/kg-1) and 1.15% of TiO2 over ultramafic rocks. The Hamutenha rocks project in the MORB-OIB field, very close to E-MORB composition, indicating that the enriched mantle (EMORB) was the source of the magma that generated ultramafic rocks. This samples show high content in Cr (1555 mg/kg-1), Ni (1855 mg/kg-1) and Co (145 mg/kg-1). The PGE show low values, except in one sample with 21 μg/kg-1) of Pd. The mineralogical analysis using SEM showed that the opaques paragenesis of Hamutenha dunitic rocks are composed by Cr, Mg and Ti spinels, chromite, magnetite, titanomagnetite, pentlandite and Ni-Fe metallic alloys. The pentlandite shows appreciable values of Ni (30.46 – 32.40 wt.% of Ni) and the chromiferous spinels 10.43 – 22.47 wt.% of Cr.

How to cite: Morais, I., Batista, M. J., Represas, P., Albardeiro, L., Prazeres, C., Plastov, J. M., Sousa, J. C., Bravo, P., Sousa, P., Carvalho, J., Rodrigues, J. F., Oliveira, D., and Cordeiro, D.: Metallogenetic potencial of the Paleoproterozoic mafic-ultramafic Hamutenha intrusion (SW Angola). New data from PLANAGEO project, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15202, https://doi.org/10.5194/egusphere-egu23-15202, 2023.

X2.114
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EGU23-16513
Lola Yesares, José María Gonzalez-Jiménez, and Rubén Piña

The Iberian Pyrite Belt (IPB), in southwestern part of the Iberian Peninsula is one of the Earth’s largest metallogenic provinces. Extending about 250 km from Sevilla and Huelva provinces, in SW Spain, to Beja in Portugal, it groups, within a belt of 40-60 km, about 90 volcanogenic massive sulfide (VMS) deposits of polymetallic nature (Cu, Pb and Zn) with untapped resources of high technological critical metals hidden in both primary ores and related in situ waste material. A careful study of the geochemistry and mineralogy of pyrite (by means of EPMA, LA-ICP-MS, FE-SEM, EBSD and FIB-HRTEM) from polymetallic massive lenses and stockwork ores from various deposits show contrasting values of high technological critical metals. Pyrite (Py-1) crystallized at earliest stage of VMS deposit formation is rich in some High-Tech critical metals like Pb, Zn, and Sb, mostly hosted as nano-to-micron-sized particles of galena and tetrahedrite. In contrast, recrystallized pyrites affected by higher temperature hydrothermal overprint, showing spongy-looking (Py-2) or homogenous (Py-3) cores surrounded by external facets, are depleted in most High-Tech critical metals, expecting Au and Bi Cu, Ag, Co and Ni. Application of same methodological approach to pyritic wastes nearby the VMS deposits show also remarkable concentrations Au, Ag, Pb, Zn and Cu. This is the first ever estimation for the revalorization and reclassification of pyrite and their mining residues as possible new resource of technological metals in the Iberian Pyrite Belt. Our results show that both primary and secondary sources are amenable for exploitation and recovery of metals necessary for the clean energy transition.

How to cite: Yesares, L., Gonzalez-Jiménez, J. M., and Piña, R.: Unveiling new resources of high technological critical metals in hydrothermal pyrite and pyritic mine residues from VMS of the Iberian Pyrite Belt  (SW Spain), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16513, https://doi.org/10.5194/egusphere-egu23-16513, 2023.

Posters virtual: Mon, 24 Apr, 14:00–15:45 | vHall GMPV/G/GD/SM

Chairpersons: Micol Bussolesi, Alessandro Cavallo, Shenghong Yang
vGGGS.22
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EGU23-6027
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ECS
Giulia Zanetta, Giovanni Grieco, Micol Bussolesi, Giuseppe Cocomazzi, Alberto Cazzaniga, Enrico Destefanis, and David Govoni

Buffering Acid Mine Drainage (AMD) is an essential part of the remediation procedures aimed to reduce the environmental impact of high-sulfur waste and tailing dumps. As solubility of most of the heavy metals dramatically decreases at increasing pH, buffering also results in a strong reduction of potentially toxic elements load of waters.

Adding carbonate-based materials, like lime, can neutralize acid mine drainage by raising pH of water and triggering precipitation of metals as hydroxides (Grieco et al., 2021), but the treatment processes are often expensive in terms of capital and operating costs. The use of mining waste as buffering agent, on the other hand, could positively contribute to a circular economy strategy for the secondary recovery of metals from abandoned mine wastes and tailings. The addition of the buffering agent to reworked tailings can result in secondary dumps with highly reduced or even absent acid mine drainage potential.

The aim of the present research is to evaluate the buffering potential and the leaching waters heavy metal load reduction of feldspar mining wastes and the effect of doping it with a minor fraction of carbonate-rich limestone quarrying wastes. The frame of the research is the evaluation of potential metal recovery from the dumps of the many abandoned sulfide mines of Sardinia as the island also hosts major feldspar mines that produce a high amount of carbonate-bearing waste.

Selected samples were collected from sulfide-rich lead-zinc Campo Pisano and gold Furtei abandoned mines. The former is part of a giant and high-grade MVT and SEDEX Zn-Pb-Fe district while the latter exploited an epithermal deposit.

Mineralogy and chemistry of the samples were determined by XRD and XRF and the acidification potential by standard Lapakko modified Acid Base Accounting tests. Leaching tests simulated the contaminant release from tailings following the Synthetic Precipitation Leaching Procedure. Leachates were analyzed for major and trace elements by ICP-MS and were then buffered with material from feldspar wastes, provided by Minerali Industriali. The Potential Toxic Element contents of buffered materials was also determined by ICP-MS.

All samples show positive Net Acid Potential Production, with higher values at Campo Pisano. Leaching tests show pH around 3 and high metal contents at Furtei. Campo Pisano leachates are only slightly acidic and the metal load is much lower due to the initial internal buffering by the carbonate gangue.

Buffering with feldspar waste was efficient on highly acidic Furtei samples, even though the amount of buffered material required is high. Doping feldspar waste with carbonate-rich limestone waste grants the same buffering capacity at a highly reduced amount of buffering agent added.

The results show that limestone waste-doped feldspar waste can be an effective acid buffering agent both for mixing with secondary tailings and for treatment of polluted acidic waters.

References

Grieco, G., Sinojmeri, A., Bussolesi, M., Cocomazzi, G. and Cavallo, A. (2021). Environmental impact variability of copper tailing dumps in Fushe Arrez (Northern Albania): The role of pyrite separation during flotation. Sustainability, 13(17), 9643.

How to cite: Zanetta, G., Grieco, G., Bussolesi, M., Cocomazzi, G., Cazzaniga, A., Destefanis, E., and Govoni, D.: Carbonate-rich limestone quarry waste as a doping agent to implement AMD buffering potential of feldspar mine waste, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6027, https://doi.org/10.5194/egusphere-egu23-6027, 2023.

vGGGS.23
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EGU23-10450
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ECS
Mitsuki Ogasawara, Junichiro Ohta, Mizuki Ishida, Kentaro Nakamura, Kazutaka Yasukawa, and Yasuhiro Kato

The northern part of Hyogo Prefecture in the southwestern Japan is a unique area having a number of large deposits that had produced various metals of industrial importance. For instance, the Nakaze deposit had been known for its extremely high-grade gold ore. The Ikuno deposit had been one of the major silver mines in Japan. Among them, the Akenobe deposit produced large amounts of tin, copper, zinc, and tungsten, as well as indium which is critical for electronic devices. The mineralization age of the deposit is a key constraint to discuss the ore genesis of such a polymetallic mineralization zone constituting large deposits of industrially important metals. However, the age of the Akenobe deposit was estimated only from the related igneous rocks by K-Ar dating, whereas a direct age determination of the metal veins has not been conducted yet. Here, we aim to directly determine the mineralization age of the veins by rhenium (Re)-osmium (Os) dating method. To apply the Re-Os dating to the veins of Akenobe mine, it is necessary to figure out the distribution of Re and Os within the ore samples. Therefore, we conducted Re-Os mapping by a Laser Ablation (LA)-Multi-Collector (MC)-ICP-MS at Ocean Resources Research Center for Next Generation, Chiba Institute of Technology. This instrument can detect extremely-low-concentrations of Re and Os simultaneously by using multiple ion-counting detectors equipped with discrete dynode type secondary electron multipliers. In the presentation, we will report the results of the Re-Os mapping using LA-MC-ICP-MS and mineralogical observation of the Akenobe ore samples, and discuss implications for the mineralization age in the Akenobe deposit.

How to cite: Ogasawara, M., Ohta, J., Ishida, M., Nakamura, K., Yasukawa, K., and Kato, Y.: Study on the mineralization age of the Akenobe Sn-Cu-W polymetallic deposit in southwest Japan, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10450, https://doi.org/10.5194/egusphere-egu23-10450, 2023.

vGGGS.24
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EGU23-10702
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ECS
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Xin Wang, Renjie Zhou, Elena Belousova, Courteney Dhnaram, Friedrich von Gnielinski, and Vladimir Lisitsin

We present multi-disciplinary datasets reporting petrography, major and trace element geochemistry, and U-Pb geochronology for the Mount Garnet Cu-Pb-Zn skarn deposit, NE Queensland, Australia. The deposit is hosted in limestones of the upper Silurian Chillagoe Formation, within the Hodgkinson Province, Mossman Orogen. Its mineralisation has been interpreted to be related to the intrusion of the Kennedy Igneous Association (~250-345 Ma), however, the exact timing is still not determined.

Petrographic observations and in suit major and trace element analysis using EPMA and LA-ICP-MS on skarn garnets reveal two generations of garnet formation. Garnets from Gt-I generation are anhedral and massive, dark brown to red in colour. They are mostly Al-rich grossular (Adr6-22Grs61-88) and show no zoning patterns. Garnets from Gt-II generation are euhedral with a yellow-green colour and porous textures. They are Fe-rich andradite (Adr10-99Grs16-77) and display oscillatory zoning. Gt-I grossulars have an enrichment in LREEs and depletion in HREEs with negative Eu anomalies, while Gt-II andradites have the opposite trend and prominent positive Eu anomalies. Both W and Sn are present in Fe-rich garnet (>10 ppm). 206Pb/238U ages of two types of garnets are ranging from ~220 Ma to 380 Ma, consistent with the zircon U-Pb age range (~295-335 Ma) from ore-related intrusions.

Our data allows the exploration of relationships between magmatism, tectonic activities, and the chronological sequence of mineralisation-related processes. A general order of events would include the very early silicification occurring within the host rock and accompanied by potential faulting, followed by the prograde and retrograde metamorphic process, which is represented by garnet, clinopyroxene, considerable vesuvianite, and calcite, along with minor wollastonite at the skarn front. Compositional variations (e.g., Mn concentration) of zoned Gt-II constrain the P-T-X condition of fluids and high Eu/Eu* and Ce/Ce* ratios within both garnets indicate a relatively oxidised skarn system. Negative correlations between Ca and REEs suggest that the incorporation and fractionation of REEs in garnet are collectively controlled by crystal chemistry and the presence of hydrothermal fluids. Further results of garnet geochronology would provide additional constraints on the nature of magmatic sources in the region.

How to cite: Wang, X., Zhou, R., Belousova, E., Dhnaram, C., von Gnielinski, F., and Lisitsin, V.: Petrological, geochemical, and geochronological characteristics of hydrothermal minerals from the Mount Garnet deposit, northeast Queensland, Australia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10702, https://doi.org/10.5194/egusphere-egu23-10702, 2023.