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Guillon S, Girard JF, Williard E, Virlogeux D, Descostes M. Modeling subsurface contaminant transport from a former open-pit uranium mine in fractured granites (La Ribière, France): Reducing uncertainties with geophysics. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 263:104343. [PMID: 38631090 DOI: 10.1016/j.jconhyd.2024.104343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 04/08/2024] [Accepted: 04/12/2024] [Indexed: 04/19/2024]
Abstract
The long-term management of tailings from former uranium (U) mines requires an in-depth understanding of the hydrogeological processes and water flow paths. In France, most of the legacy U mines are located in fractured crystalline (plutonic) rocks, where the intrinsic subsurface heterogeneity adds to the uncertainties about the former extraction and milling activities and the state of the mine when production was ceased. U ores were mainly processed by sulfuric acid leaching, leading to high-sulfate-content mill tailings now contained in several tailing storage facilities (TSFs). The La Ribière site, located in western central France, is a former open-pit and underground U mine, closed in 1992 and used to store mill tailings. This site is being used as a test case to establish a workflow in order to explain and predict water flow and subsurface contaminant transport. A conceptual model of water flow and sulfate transport, at the scale of the La Ribière watershed, is first developed based on available information and hydrogeochemical monitoring. Recent geophysical investigations allows refining this model. Electrical Resistivity Tomography (ERT) proves to be efficient at localizing the extent of the highly conductive sulfate plume inherited from the U-mill tailings, but also at imaging the weathering profile. Magnetic Resonance Sounding (MRS), despite the limited signal intensity due to the low porosity in crystalline rocks, gives some insight into the porosity values, the depth of the fractured layer and the location of the low-porosity ore-processing muds. Based on this conceptual model, a 3D flow and non-reactive transport model with the METIS code is developed and calibrated. This model allows predicting the evolution of the sulfate plume, but will also be used in future investigations, to build reactive transport models with simplified hydrogeology for U and other reactive contaminants.
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Affiliation(s)
- S Guillon
- Mines Paris, PSL University, Centre de Geosciences, 35 rue Saint Honoré, 77300 Fontainebleau, France.
| | - J-F Girard
- ITES, Institut Terre et Environnement de Strasbourg, University of Strasbourg, CNRS, France
| | | | - D Virlogeux
- ORANO Mining, Chatillon, France; GEOYODA Consultant, Bordeaux, France
| | - M Descostes
- Mines Paris, PSL University, Centre de Geosciences, 35 rue Saint Honoré, 77300 Fontainebleau, France; ORANO Mining, Chatillon, France
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2
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Reymond M, Descostes M, Besançon C, Leermakers M, Billon S, Cherfallot G, Muguet M, Beaucaire C, Smolikova V, Patrier P. Assessment of 226Ra and U colloidal transport in a mining environment. CHEMOSPHERE 2023; 338:139497. [PMID: 37451635 DOI: 10.1016/j.chemosphere.2023.139497] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 07/05/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
The colloidal transport of trace (Fe, Al, Ba, Pb, Sr, U) and ultra-trace (226Ra) elements was studied in a mining environment. An original approach combining 0.45 μm filtered water sampling, the Diffusive Gradient in Thin films (DGT) technique, mineralogical characterization, and geochemical modelling was developed and tested at 17 sampling points. DGT was used for the truly dissolved fraction of the elements of interest, while the 0.45 μm filtration includes both colloidal and truly dissolved fractions (together referred to as total dissolved fraction). Results indicated a colloidal fraction for Al (up to 50%), Ba (up to 86%), and Fe (up to 99%) explained by the presence of submicrometric grains of kaolinite, barite, and ferrihydrite, respectively. Furthermore, the total dissolved 226Ra concentration in the water samples reached up to 10-25 Bq/L (1.2-3.0 10-12 mol/L) at 3 sampling points, while the truly dissolved aqueous 226Ra concentrations were in the mBq/L range. Such high total dissolved concentrations are explained by retention on colloidal barite, accounting for 95% of the total dissolved 226Ra concentration. The distribution of 226Ra between the truly dissolved and colloidal fractions was accurately reproduced using a (Rax,Ba1-x)SO4 solid solution, with values of the Guggenheim parameter a0 close to ideality. 226Ra sorption on ferrihydrite and kaolinite, other minerals well known for their retention properties, could not explain the measured colloidal fractions despite their predominance. This illustrates the key role of barite in such environments. The measured concentrations of total dissolved U were very low at all the sampling points (<4.5 10-10 mol/L) and the colloidal fraction of U accounted for less than 65%. U sorption on ferrihydrite could account for the colloidal fraction. This original approach can be applied to other trace and ultra-trace elements to complement when necessary classical environmental surveys usually performed by filtration on 0.45 μm.
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Affiliation(s)
- Marine Reymond
- Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), UMR 7285, Université de Poitiers, CNRS, HydrASA, F-86073, Poitiers, France
| | - Michael Descostes
- Orano Environmental R&D Dpt, 125 avenue de Paris, 92320, Châtillon, France; Centre de Géosciences, MINES Paris, PSL University, 35 rue St Honoré, 77300, Fontainebleau, France
| | - Clémence Besançon
- Orano Environmental R&D Dpt, 125 avenue de Paris, 92320, Châtillon, France.
| | - Martine Leermakers
- Analytical, Environmental & Geo-Chemistry (AMGC), Vrije Universiteit Brussels (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Sophie Billon
- Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), UMR 7285, Université de Poitiers, CNRS, HydrASA, F-86073, Poitiers, France
| | - Gaël Cherfallot
- Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), UMR 7285, Université de Poitiers, CNRS, HydrASA, F-86073, Poitiers, France
| | - Marie Muguet
- Orano Environmental R&D Dpt, 125 avenue de Paris, 92320, Châtillon, France.
| | | | - Vendula Smolikova
- Analytical, Environmental & Geo-Chemistry (AMGC), Vrije Universiteit Brussels (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Patricia Patrier
- Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), UMR 7285, Université de Poitiers, CNRS, HydrASA, F-86073, Poitiers, France
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3
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Sirven JB, Szenknect S, Vors E, Anzalone E, Benarib S, Sarr PM, Reiller PE, Mesbah A, Dacheux N, Vercouter T, Descostes M. Time-resolved laser-induced fluorescence spectroscopy and chemometrics for fast identification of U(VI)-bearing minerals in a mining context. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 296:122671. [PMID: 37031480 DOI: 10.1016/j.saa.2023.122671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/16/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
We evaluated the potential of time-resolved laser-induced fluorescence spectroscopy (TRLFS) combined with chemometric methods for fast identification of U(VI)-bearing minerals in a mining context. We analyzed a sample set which was representative of several environmental conditions. The set consisted of 80 uranium-bearing samples related to mining operations, including natural minerals, minerals with uranium sorbed on the surface, and synthetic phases prepared and characterized specifically for this study. The TRLF spectra were processed using the Ward algorithm and the K-nearest neighbors (KNN) method to reveal similarities between samples and to rapidly identify the uranium-bearing phase and the associated mineralogical family. The predictive models were validated on an independent dataset, and then applied to test samples mostly taken from U mill tailings. Identification results were found to be in accordance with the available characterization data from X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX). This work shows that TRLFS can be an effective decision-making tool for environmental investigations or geological prospection, considering the large diversity of uranium-bearing mineral phases and their low concentration in environmental samples.
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Affiliation(s)
- Jean-Baptiste Sirven
- Université Paris-Saclay, CEA, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), F-91191 Gif-sur-Yvette, France.
| | - Stéphanie Szenknect
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France
| | - Evelyne Vors
- Université Paris-Saclay, CEA, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), F-91191 Gif-sur-Yvette, France
| | - Eddie Anzalone
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France
| | - Sofian Benarib
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France
| | - Papa-Masserigne Sarr
- Université Paris-Saclay, CEA, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), F-91191 Gif-sur-Yvette, France
| | - Pascal E Reiller
- Université Paris-Saclay, CEA, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), F-91191 Gif-sur-Yvette, France
| | - Adel Mesbah
- IRCELYON, CNRS - UCBL, 2 avenue Albert Einstein, 69626 Villeurbanne Cedex, France
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France
| | - Thomas Vercouter
- Université Paris-Saclay, CEA, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), F-91191 Gif-sur-Yvette, France
| | - Michaël Descostes
- ORANO Mining, Environmental R&D Dpt, 125 avenue de Paris, 92320 Chatillon, France; Centre de Géosciences, MINES Paris, PSL Research University, Paris, France
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Escario S, Seigneur N, Collet A, Regnault O, de Boissezon H, Lagneau V, Descostes M. A reactive transport model designed to predict the environmental footprint of an 'in-situ recovery' uranium exploitation. JOURNAL OF CONTAMINANT HYDROLOGY 2023; 254:104106. [PMID: 36634485 DOI: 10.1016/j.jconhyd.2022.104106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/25/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
Worldwide, most uranium production relies on the 'in situ recovery' (ISR) extraction technique. This consists of dissolving the ore using a leaching solution (acid or alkaline) directly within the deposit through a series of injection and extraction wells. Due to the nature of the injected ISR solutions, the water quality of the aquifer could be affected. Reactive transport modeling is a powerful tool for predicting fluid flow and geochemical reactions in ISR reservoirs. In this study we present a coupled 3D environmental geochemical model (EGM) (based on the HYTEC reactive transport software), capable of predicting the physico-chemical conditions in an acid-leaching ISR uranium mine and its environmental footprint on the aquifer in the years following the closure of the production block. The model was validated at the KATCO mine (Kazakhstan) on two different and independent production blocks, over 10 years after their closure. The model shows that incorporating two main geochemical processes, (1) cationic sorption on clay surfaces (smectite-beidellite) and (2) precipitation of gypsum (CaSO4.2H2O), successfully reproduces the measured well data (pH, acidity and SO4) over short- and long-term time scales. Clay surface sites remain mostly saturated in protons during the production phase. Simulations show that sorbed protons on the clay surfaces maintains the acid conditions for a longer period of time. The environmental impact model was also compared to a pre-existing model specifically developed for production simulation purposes: differences are observed as expected for the uranium production, but also for the impact distances, due to differences in the considered reactive mineralogical paragenesis. Thus, the choice of geochemical model should be made with due regard for the desired objectives. This work will assist the mine operator by providing a tool capable of assessing both the short- and long-term environmental footprints of the ISR production operation conditions and of identifying the best remediation strategy.
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Affiliation(s)
- S Escario
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France.
| | - N Seigneur
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France
| | - A Collet
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| | - O Regnault
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| | - H de Boissezon
- ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| | - V Lagneau
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France
| | - M Descostes
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
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5
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Besançon C, Sardini P, Savoye S, Descostes M, Gérard M. Quantifying 226Ra activity in a complex assemblage of 226Ra-bearing minerals using alpha autoradiography and SEM/EDS. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 251-252:106951. [PMID: 35780670 DOI: 10.1016/j.jenvrad.2022.106951] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/12/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
226Ra is an ultra-trace element with important environmental implications for many industries (including water treatment and oil and mineral extraction). Its extremely low concentrations in natural environments do not allow for direct observation and measurement of the 226Ra-bearing minerals governing 226Ra mobility. To better understand the retention processes for 226Ra in rocks and soil, a synthesized assemblage of 226Ra-doped minerals was made, combining montmorillonite, ferrihydrite and barite. A new methodology was developed using alpha activity maps acquired using alpha autoradiography, and elemental maps by using SEM/EDS. These maps were processed using a global approach, considering the entirety of the signal. The comparison of the alpha activity map and the elemental map enabled a correlation to be established between the 226Ra activity and the chemical composition and identification of the main 226Ra-bearing mineral of the assemblage, from which we were able to estimate the contribution of each mineral to the total activity of the assemblage, and to quantify the 226Ra-activity for each mineral. This methodology makes it possible to link mineralogy and occurrence of 226Ra at the scale of the mineral (tens of μm). It can be applied to natural samples, including fine-grained samples with a complex mineralogy.
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Affiliation(s)
- Clémence Besançon
- Environmental R&D Department, ORANO Mining, 125 Avenue de Paris, 92320, Chatillon, France; Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, 4 Place Jussieu, 75005, Paris, France.
| | - Paul Sardini
- Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), Université de Poitiers, Rue Michel Brunet, Bat. 35, 86000, Poitiers, France
| | - Sébastien Savoye
- Des, Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
| | - Michael Descostes
- Environmental R&D Department, ORANO Mining, 125 Avenue de Paris, 92320, Chatillon, France; Centre de Géosciences, MINES ParisTech, PSL University, 35 Rue St Honoré, Fontainebleau, 77300, France
| | - Martine Gérard
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, 4 Place Jussieu, 75005, Paris, France
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6
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Coral T, Placko AL, Beaufort D, Tertre E, Bernier-Latmani R, Descostes M, De Boissezon H, Guillon S, Rossi P. Biostimulation as a sustainable solution for acid neutralization and uranium immobilization post acidic in-situ recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153597. [PMID: 35114226 DOI: 10.1016/j.scitotenv.2022.153597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Major uranium (U) deposits worldwide are exploited by acid leaching, known as 'in-situ recovery' (ISR). ISR involves the injection of an acid fluid into ore-bearing aquifers and the pumping of the resulting metal-containing solution through cation exchange columns for the recovery of dissolved U. Rehabilitation of ISR-impacted aquifers could be achieved through natural attenuation, or via biostimulation of autochthonous heterotrophic microorganisms due to the associated acid neutralization and trace metal immobilization. In this study, we analyzed the capacity of pristine aquifer sediments impacted by diluted ISR fluids to buffer pH and immobilize U. The experimental setup consisted of glass columns, filled with sediment from a U ore-bearing aquifer, through which diluted ISR fluids were flowed continuously. The ISR solution was obtained from ISR mining operations at the Muyunkum and Tortkuduk deposits in Kazakhstan. Following this initial phase, columns were biostimulated with a mix of molasses, yeast extract and glycerol to stimulate the growth of autochthonous heterotrophic communities. Experimental results showed that this amendment efficiently promoted the activity of acid-tolerant bacterial guilds, with pH values rising from 4.8 to 6.5-7.0 at the outlet of the stimulated columns. The reduction of sulfate, nitrate, and metals as well as dissimilatory nitrate reduction to ammonia induced the rise in pH values, in agreement with geochemical modelling results. Biostimulation efficiently promoted the complete immobilization of U, with the accumulation of up to 3343 ppm in the first few centimeters of the columns. Synchrotron analysis and SEM-EDS revealed that up to 60% of the injected hexavalent U was immobilized as tetravalent non-crystalline U onto bacterial cell surfaces. 16S rDNA amplicon analysis and qPCR data suggested a predominant role played for members of the Phylum Firmicutes (from the genera Clostridium, Pelosinus and Desulfosporosinus) in biological U reduction and immobilization.
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Affiliation(s)
- Thomas Coral
- Central Environmental Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Station 2, 1015 Lausanne, Switzerland
| | - Anne-Laure Placko
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320 Chatillon, France
| | - Daniel Beaufort
- Université de Poitiers/CNRS, UMR 7285 IC2MP, Equipe HydrASA, 5 rue Albert Turpain, 86073 Poitiers Cedex 9, France.
| | - Emmanuel Tertre
- Université de Poitiers/CNRS, UMR 7285 IC2MP, Equipe HydrASA, 5 rue Albert Turpain, 86073 Poitiers Cedex 9, France.
| | - Rizlan Bernier-Latmani
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Station 6, 1015 Lausanne, Switzerland.
| | - Michael Descostes
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320 Chatillon, France; Centre de Géosciences, MINES ParisTech, PSL University. 35 rue St Honoré, 77300 Fontainebleau, France
| | - Hélène De Boissezon
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320 Chatillon, France
| | - Sophie Guillon
- Centre de Géosciences, MINES ParisTech, PSL University. 35 rue St Honoré, 77300 Fontainebleau, France.
| | - Pierre Rossi
- Central Environmental Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Station 2, 1015 Lausanne, Switzerland.
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Beaumais A, Mangeret A, Suhard D, Blanchart P, Neji M, Cazala C, Gourgiotis A. Combined U-Pb isotopic signatures of U mill tailings from France and Gabon: A new potential tracer to assess their fingerprint on the environment. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128484. [PMID: 35739667 DOI: 10.1016/j.jhazmat.2022.128484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/08/2022] [Accepted: 02/11/2022] [Indexed: 06/15/2023]
Abstract
Uranium milling activities have produced high volumes of long-lived radioactive processed wastes stored worldwide in near surface environment. The aim of this study is to highlight relevant tracers that can be used for environmental impact assessment studies involving U mill tailings. A multi-tracer study involving elemental content, 238U decay products disequilibria and stable Pb isotopes was performed in different types of U mill tailings (alkaline, acid, neutralized acid) collected from five Tailings Management Facilities in France (Le Bosc, L'Ecarpière, Le Bernardan, and Bellezane) and Gabon (Mounana). Our results showed that U and Pb concentrations range between 30 and 594 ppm and 66-805 ppm, respectively. These tailings have a strong disequilibrium of (234U/238U) and (230Th/238U) activity ratios (1.27-1.87 and 6-65, respectively), as well as higher 206Pb/207Pb (1.86-7.15) and lower 208Pb/207Pb (0.22-2.39) compared to geochemical background ((234U/238U) and (230Th/238U) equal to unity; 206Pb/207Pb = 1.20; 208Pb/207Pb = 2.47). In situ analyzes (SEM, SIMS) showed that Pb-bearing phases with high 206Pb/207Pb are related to remaining U-rich phases, S-rich phases and potentially clay minerals or oxyhydroxides. We suggest that the combination of the 206Pb/207Pb with the (234U/238U) ratio is a relevant tool for the fingerprinting of the impact of U milling activities on the environment.
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Affiliation(s)
- Aurélien Beaumais
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France
| | - Arnaud Mangeret
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France
| | - David Suhard
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France
| | - Pascale Blanchart
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France
| | - Mejdi Neji
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France
| | - Charlotte Cazala
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France
| | - Alkiviadis Gourgiotis
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SEDRE/LELI, LETIS, USDR, PSE-SANTE/SESANE/LRSI, 31 Av. de la Division Leclerc, Fontenay-aux-Roses 92260, France.
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8
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Lahrouch F, Baptiste B, Dardenne K, Rothe J, Elkaim E, Descostes M, Gerard M. Uranium speciation control by uranyl sulfate and phosphate in tailings subject to a Sahelian climate, Cominak, Niger. CHEMOSPHERE 2022; 287:132139. [PMID: 34509019 DOI: 10.1016/j.chemosphere.2021.132139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Long-term uranium mobility in tailings is an environmental management issue. The present study focuses on two U-enriched layers, surficial and buried 14.5 m, of the tailings pile of Cominak, Niger. The acidic and oxidizing conditions of the tailings pile combined with evapotranspiration cycles related to the Sahelian climate control U speciation. Uraninite, brannerite, and moluranite as well as uranophane are relict U phases. EXAFS spectroscopy, HR-XRD, and SEM/WDS highlight the major role of uranyl sulfate groups in uranium speciation. Uranyl phosphate neoformation in the buried layer (paleolayer) acts as an efficient trap for uranium.
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Affiliation(s)
- Florian Lahrouch
- Sorbonne Université, CNRS UMR7590, MNHN, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 4 Place Jussieu, Paris, F- 75005, France.
| | - Benoit Baptiste
- Sorbonne Université, CNRS UMR7590, MNHN, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 4 Place Jussieu, Paris, F- 75005, France
| | - Kathy Dardenne
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (INE), P.O. Box 3640, Karlsruhe, D-76021, Germany
| | - Jörg Rothe
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (INE), P.O. Box 3640, Karlsruhe, D-76021, Germany
| | - Erik Elkaim
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, Gif-sur-Yvette Cedex, F-91192, France
| | - Michael Descostes
- ORANO Mines, Environmental R & D Department, 125 Avenue de Paris, Châtillon, F-93320, France; Centre de Géosciences, MINES ParisTech, PSL University, 35 rue St Honoré, Fontainebleau, 77300, France
| | - Martine Gerard
- Sorbonne Université, CNRS UMR7590, MNHN, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 4 Place Jussieu, Paris, F- 75005, France.
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9
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Long-Term Evolution of Uranium Mobility within Sulfated Mill Tailings in Arid Regions: A Reactive Transport Study. MINERALS 2021. [DOI: 10.3390/min11111201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Management of mill tailings is an important part of mining operations that aims at preventing environmental dispersion of contaminants of concern. To this end, geochemical models and reactive transport modeling provide a quantitative assessment of the mobility of the main contaminants. In arid regions with limited rainfall and intense evaporation, solutes transport may significantly differ from the usual gravity-driven vertical flow. In the uranium tailings of the Cominak mine (Niger), these evaporative processes resulted in the crystallization of gypsum, and to a lesser extent jarosite, and in the formation of surface levels of sulfated gypcrete, locally enriched in uranium. We present a fully coupled reactive transport modeling approach using HYTEC, encompassing evaporation, to quantitatively reproduce the complex sequence of observed coupled hydrogeochemical processes. The sulfated gypcrete formation, porosity evolution and solid uranium content were successfully reproduced at the surface and paleosurfaces of the tailing deposit. Simulations confirm that high solubility uranyl-sulfate phase may form at the atmospheric boundary where evaporation takes place, which would then be transformed into uranyl-phosphate phases after being watered or buried under fresh tailings. As these phases usually exhibit a lower solubility, this transition is beneficial for mine operators and tailings management.
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Martin A, Hassan-Loni Y, Fichtner A, Péron O, David K, Chardon P, Larrue S, Gourgiotis A, Sachs S, Arnold T, Grambow B, Stumpf T, Montavon G. An integrated approach combining soil profile, records and tree ring analysis to identify the origin of environmental contamination in a former uranium mine (Rophin, France). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 747:141295. [PMID: 32777513 DOI: 10.1016/j.scitotenv.2020.141295] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/22/2020] [Accepted: 07/25/2020] [Indexed: 06/11/2023]
Abstract
Uranium mining and milling activities raise environmental concerns due to the release of radioactive and other toxic elements. Their long-term management thus requires a knowledge of past events coupled with a good understanding of the geochemical mechanisms regulating the mobility of residual radionuclides. This article presents the results on the traces of anthropic activity linked to previous uranium (U) mining activities in the vicinity of the Rophin tailings storage site (Puy de Dôme, France). Several complementary approaches were developed based on a study of the site's history and records, as well as on a radiological and chemical characterization of soil cores and a dendrochronology. Gamma survey measurements of the wetland downstream of the Rophin site revealed a level of 1050 nSv.h-1. Soil cores extracted in the wetland showed U concentrations of up to 1855 mg.kg-1, which appears to be associated with the presence of a whitish silt loam (WSL) soil layer located below an organic topsoil layer. Records, corroborated by prior aerial photographs and analyses of 137Cs and 14C activities, suggest the discharge of U mineral particles while the site was being operated. Moreover, lead isotope ratios indicate that contamination in the WSL layer can be discriminated by a larger contribution of radiogenic lead to total lead. The dendroanalysis correlate U emissions from Rophin with the site's history. Oak tree rings located downstream of the site contain uranium concentrations ten times higher than values measured on unaffected trees. Moreover, the highest U concentrations were recorded not only for the operating period, but more surprisingly for the recent site renovations as well. This integrated approach corroborates that U mineral particles were initially transported as mineral particles in Rophin's watershed and that a majority of the deposited uranium appears to have been trapped in the topsoil layer, with high organic matter content.
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Affiliation(s)
- A Martin
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France
| | - Y Hassan-Loni
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France
| | - A Fichtner
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France; Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - O Péron
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France.
| | - K David
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France
| | - P Chardon
- LPC, UMR 6533, CNRS/Université Clermont Auvergne, 4, rue Ledru, 63057 Clermont-Ferrand cedex, France
| | - S Larrue
- GEOLAB, UMR 6042, CNRS/Université Clermont Auvergne, 4, rue Ledru, 63057 Clermont-Ferrand cedex, France
| | - A Gourgiotis
- Institut de Radioprotection et de Sûreté Nucléaire - PSE/ENV - SEDRE/LELI, Fontenay-aux-Roses, 92262, France
| | - S Sachs
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - T Arnold
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - B Grambow
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France
| | - T Stumpf
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - G Montavon
- Laboratoire SUBATECH, UMR 6457, IMT Atlantique/Université de Nantes/CNRS/IN2P3 4 Rue Alfred Kastler, 44307 Nantes, France
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de Boissezon H, Levy L, Jakymiw C, Distinguin M, Guerin F, Descostes M. Modeling uranium and 226Ra mobility during and after an acidic in situ recovery test (Dulaan Uul, Mongolia). JOURNAL OF CONTAMINANT HYDROLOGY 2020; 235:103711. [PMID: 32949982 DOI: 10.1016/j.jconhyd.2020.103711] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/06/2020] [Accepted: 08/30/2020] [Indexed: 06/11/2023]
Abstract
This article presents the results of groundwater monitoring over a period of six years and the interpretation of these results by a reactive transport model, following an In Situ Recovery (ISR) test on the Dulaan Uul uranium deposit in Mongolia. An environmental monitoring survey was set up using 17 piezometers, from which it has been possible to describe the changes in the water composition before, during and after the ISR test. The water quality before the start of mining activities rendered it unfit for human consumption. During and after the test, a descent of the saline plume was observed, resulting in a dilution of the injection solutions. After a rapid decrease to pH = 1.13 during the production phase of the ISR test, the pH stabilized at around 4 in the production area and 5.5 below the production cell one year after the end of the test. Uranium and radium were being naturally attenuated. Uranium returned to background concentrations (0.3 mg/L) after two years and the measured 226Ra concentrations represent no more than 10% of the expected concentrations during production (75 Bq/L). The modeling of the contaminants of concern mobility, namely pH and concentrations of sulfate, uranium and 226Ra, is based on several key complementary mechanisms: density flow, cation exchange with clay minerals and co-precipitation of 226Ra in the barite. The modeling results show that the observed plume descent and sulfate dilution can only be predicted if consideration of a high-density flow is included. Similarly, the changes in pH and 226Ra concentration are only correctly predicted when the cationic exchanges with the clays and the co-precipitation reaction within the barite using the solid solution theory are integrated into the models. Finally, the proper representation of the changes in water composition at the scale of the test requires the use of a sufficiently fine mesh (1 m × 1 m cell) to take into account the spatial variability of hydrogeological (permeability distribution in particular) and geological (reduced, oxidized and mineralized facies distributions) parameters.
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Affiliation(s)
- H de Boissezon
- ORANO Mining, R&D Dept, 125 Avenue de Paris, 92320 Chatillon, France.
| | - L Levy
- ORANO Mining, R&D Dept, 125 Avenue de Paris, 92320 Chatillon, France
| | - C Jakymiw
- ORANO Mining, R&D Dept, 125 Avenue de Paris, 92320 Chatillon, France
| | - M Distinguin
- COGEGOBI, ICC Tower, Jamyan Gun Street 9, Ulaanbaatar, Mongolia
| | - F Guerin
- ORANO Mining, R&D Dept, 125 Avenue de Paris, 92320 Chatillon, France
| | - M Descostes
- ORANO Mining, R&D Dept, 125 Avenue de Paris, 92320 Chatillon, France
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12
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Angileri A, Sardini P, Beaufort D, Amiard G, Beaufort MF, Nicolai J, Siitari-Kauppi M, Descostes M. Mobility of daughter elements of 238U decay chain during leaching by In Situ Recovery (ISR): New insights from digital autoradiography. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 220-221:106274. [PMID: 32560879 DOI: 10.1016/j.jenvrad.2020.106274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 03/13/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
In highly permeable sedimentary rock formations, U extraction by in-situ leaching techniques (ISR - In-Situ Recovery) is generally considered to have a limited environmental impact at ground level. Significantly, this method of extraction produces neither mill tailings nor waste rocks. Underground, however, the outcome for 238U daughter elements in aquifers is not well known because of their trace concentrations in the host rocks. Thus, understanding the in-situ mobility of these elements remains a challenge. Two samples collected before and after six months of ISR experiments (Dulaan Uul, Mongolia) were studied with the help of a digital autoradiography technique (DA) of alpha particles, bulk alpha spectrometry, and complementary petrographic observation methods. These techniques demonstrate that before and after leaching, the radioactivity is concentrated in altered and microporous Fe-Ti oxides. Most of the daughter elements of U remain trapped in the rock after the leaching process. DA confirms that the alpha activity of the Fe-Ti oxides remains high after uranium leaching, and the initial secular equilibrium of the 238U series for 230Th to 210Po daughter elements (including 226Ra) of the fresh rocks is maintained after leaching. While these findings should be confirmed by more systematic studies, they already identify potential mechanisms explaining why the U-daughter concentrations in leaching water are low.
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Affiliation(s)
- A Angileri
- IC2MP - Hydrasa, Poitiers University UMR 7285 CNRS, France
| | - P Sardini
- IC2MP - Hydrasa, Poitiers University UMR 7285 CNRS, France.
| | - D Beaufort
- IC2MP - Hydrasa, Poitiers University UMR 7285 CNRS, France
| | - G Amiard
- PPRIME, Poitiers University, UPR 3346 CNRS, France
| | - M F Beaufort
- PPRIME, Poitiers University, UPR 3346 CNRS, France
| | - J Nicolai
- PPRIME, Poitiers University, UPR 3346 CNRS, France
| | - M Siitari-Kauppi
- Radiochemistry Laboratory, University of Helsinki, Helsinki, Finland
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Chautard C, Beaucaire C, Gerard M, Roy R, Savoye S, Descostes M. Geochemical characterization of uranium mill tailings (Bois Noirs Limouzat, France) highlighting the U and 226Ra retention. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 218:106251. [PMID: 32421585 DOI: 10.1016/j.jenvrad.2020.106251] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 03/07/2020] [Accepted: 03/14/2020] [Indexed: 06/11/2023]
Abstract
As with other metals, the management of tailings from former uranium (U) mines requires a good knowledge of the geochemical mechanisms governing the retention of radioelements of interest: U and 226Ra. This article presents the results of the study of the bearing phases featuring these two radioelements within the Bois Noirs Limouzat tailings storage facility (Loire), the only site in France where the tailings (a sandy silt facies and a clayey silt facies) are currently stored only under water. The aim is to gain a better understanding of their respective mobility under current storage conditions. For this purpose, a multi-scale approach was adopted combining historical research and airborne image analysis to select the core location, chemical and radiological analyses, mineralogical characterizations supplemented by sequential extractions (two specifically developed protocols). The results show that U and 226Ra are mainly found in the clayey silt facies with an average U concentration of 243.3 ppm (132.3 ppm in the sandy silt facies) and an average 226Ra mass activity of 64.7Bq/g (18.0Bq/g in the sandy silt facies). These results are in accordance with the initial U grade of the ore (2‰), the extraction efficiency of the ore processing plant (95%) and the age of mineralization (305 Ma). The approach adopted made it possible to highlight several mineralogical traps available for each radioelement, regardless of the facies type. Thus, a significant part of the U is still trapped within the primary phases, resistant to treatment and therefore relatively immobile under current storage conditions (49.6%-77.8% for the sandy silt facies and 27.2%-36% for the clayey silt facies). Most of the leached U is mainly associated with weakly crystalised iron oxyhydroxides (8.7%-42.4% for the sandy silt facies and 50.9%-71.8% for the clayey silt facies) and to a lesser extent with clay minerals (5%-12.3% for the sandy silt facies and 0.8%-11.5% for the clayey silt facies). For the 226Ra, irrespective of the facies type, a significant part remains trapped within phosphate phases, resistant to the leaching process and therefore also relatively immobile under storage conditions (24.4%-38.9% for the silty sandy silt facies and 39.9%-98.9% for the clayey silt facies). Sequential extractions revealed a different geochemistry of 226Ra depending on the facies. For the silty sandy silt facies, most of the 226Ra is mainly associated with the clay minerals (6.4%-69.2%) and to a lesser extent with iron oxyhydroxides, barite or aluminum phosphate sulphate minerals (APS) (6.4%-33.9%). For the clayey silt facies, most of the 226Ra is mainly associated with iron oxyhydroxides, barite or APS (6.4%-53.3%) and to lesser extent clay minerals (0.4%-6.8%). The leaching process did not allow the differentiation between the contributions of each of these phases to the retention of 226Ra. At last, all the identified bearing phases demonstrate that the U is relatively immobile under the current storage conditions, irrespective of the facies. For the 226Ra, the bearing phases differ according to the facies. Within the sandy silt facies, the 226Ra is mainly borne by clay minerals and can be mobilised more easily. However, the sandy silt facies represents only one third of the tailings currently.
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Affiliation(s)
| | - Catherine Beaucaire
- Den-Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.
| | - Martine Gerard
- Sorbonne Université, CNRS UMR7590, MNHN, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), 4 Place Jussieu, F-75005, Paris, France.
| | - Régis Roy
- Orano Canada Inc., 817 - 45th Street West, Saskatoon, SK, S7L 5X2, Canada.
| | - Sébastien Savoye
- Den-Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.
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14
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Ballini M, Chautard C, Nos J, Phrommavanh V, Beaucaire C, Besancon C, Boizard A, Cathelineau M, Peiffert C, Vercouter T, Vors E, Descostes M. A multi-scalar study of the long-term reactivity of uranium mill tailings from Bellezane site (France). JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 218:106223. [PMID: 32174445 DOI: 10.1016/j.jenvrad.2020.106223] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/18/2020] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
The mill tailings from uranium mines constitute very low-level, long-lived, radioactive process waste. Their long-term management therefore requires a good understanding of the geochemical mechanisms regulating the mobility of residual uranium and radium-226. This article presents the results of the detailed characterization of the tailings resulting from the dynamic leaching processes used on the ore of the La Crouzille mining division and stored at the Bellezane site (Haute-Vienne, France) for over 25 years. A multi-scalar and multidisciplinary approach was developed based on a study of the site's history, on the chemical, radiological and mineralogical characterizations of the solid fraction of the tailings, and on porewater analyses. These were complemented by thermodynamic equilibrium models to predict the long-term mobility of U and 226Ra. Weakly acidic (pH = 6.35) and oxidizing (Eh = 138 mV/SHE) porewaters had a sulfated-magnesian facies ([SO4]tot = 43 mmol/L; [Mg]tot = 33 mmol/L) with an accessory calcium bicarbonate component (TIC = 25 mmol/L; [Ca]tot = 13 mmol/L) and dissolved concentrations of uranium and 226Ra of 12 × 10-6 mol/L and 0.58 Bq/L respectively. Ultra-filtration at 10 kDa indicated the absence of colloidal phases. The characterization of the tailings confirmed their homogeneity from a radiological, chemical and mineralogical point of view. The residual U and 226Ra concentrations measured in the solid were 160 ppm and 25 Bq/g respectively, in accordance with the initial ore grades and mill yields, or more than 99% of the total stock. In terms of chemical and mineralogical composition, the tailings were mainly composed of minerals from the granitic ore (quartz, potassium feldspar, plagioclases and micas) in association with their weathering products (smectite and ferric oxyhydroxides) and with neo-formed minerals following rapid diagenesis after neutralization of the tailings before their emplacement (gypsum and barite). All these minerals are effective traps for the retention of U and 226Ra. The uranium is distributed partly in micrometer scale uraninite and coffinite refractory phases embedded in grains of quartz, and partly sorbed to smectite and ferric oxyhydroxides. The 226Ra on the other hand is trapped mainly within the barite. The aqueous concentrations of U and 226Ra could be described using a thermodynamic approach so that their long-term mobility can subsequently be assessed by modeling. The paragenesis of the tailings could be seen to be stable over time with the exception of neo-formed gypsum and calcite, which will gradually dissolve. The presence of retention traps offering surplus capacity, i.e. smectite, ferric oxyhydroxides and barite, will maintain the U and the 226Ra at very low aqueous concentrations, even under oxidizing conditions. Moreover, the low permeability of the mill tailings leads, in the case of 226Ra, to behavior dictated only by the radioactive decay.
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Affiliation(s)
- M Ballini
- ORANO Mining, R&D Dpt, 125 Avenue de Paris, F-92330, Châtillon, France
| | - C Chautard
- ORANO Mining, R&D Dpt, 125 Avenue de Paris, F-92330, Châtillon, France
| | - J Nos
- ORANO Mining, R&D Dpt, 125 Avenue de Paris, F-92330, Châtillon, France
| | - V Phrommavanh
- ORANO Mining, R&D Dpt, 125 Avenue de Paris, F-92330, Châtillon, France
| | - C Beaucaire
- DEN, Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
| | - C Besancon
- ORANO Mining, R&D Dpt, 125 Avenue de Paris, F-92330, Châtillon, France; Institut de Minéralogie de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, F-75005, Paris, France
| | - A Boizard
- Université de Lorraine, CNRS, CREGU, GeoRessources, F-54000, Nancy, France
| | - M Cathelineau
- Université de Lorraine, CNRS, CREGU, GeoRessources, F-54000, Nancy, France
| | - C Peiffert
- Université de Lorraine, CNRS, CREGU, GeoRessources, F-54000, Nancy, France
| | - T Vercouter
- DEN, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), CEA, Université Paris-Saclay, F-91191, Gif sur Yvette, France
| | - E Vors
- DEN, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), CEA, Université Paris-Saclay, F-91191, Gif sur Yvette, France
| | - M Descostes
- ORANO Mining, R&D Dpt, 125 Avenue de Paris, F-92330, Châtillon, France.
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Billon S, Sardini P, Angileri A, Beaucaire C, Parneix JC, Siitari-Kauppi M, Descostes M. Quantitative imaging of 226Ra ultratrace distribution using digital autoradiography: Case of doped celestines. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 217:106211. [PMID: 32217244 DOI: 10.1016/j.jenvrad.2020.106211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/12/2020] [Accepted: 02/15/2020] [Indexed: 06/10/2023]
Abstract
The ability of the autoradiographic device BeaQuant™ is evaluated herein to quantitatively map the ultratrace element 226Ra distributed spatially in celestine (SrSO4) grains/crystals. 226Ra doped celestines have been obtained from coprecipitation and recrystallization experiments, and have been characterized with high purity germanium gamma detector (HPGe), giving specific activities ranging from 3251 to 32523 Bq.g-1. Alpha autoradiographs of polished sections from doped celestines have been obtained using BeaQuant™. These alpha maps have been compared to the celestine grains/crystals arrangement observed with a scanning electron microscope (SEM). At the sample scale, celestine grains are responsible of an alpha signal, indicating that 226Ra is detectable in celestine from its alpha emissions. 226Ra distribution has also been investigated at the celestine grains/crystals scale: the crystal/grain properties do not allow to decide if the distribution process is homogeneous or not, i.e. if there is a chemical zoning into the crystal/grain. The counting of alpha particles by autoradiography has been compared with the total activity of the 226Ra doped celestines by gamma counting (HPGe technique). This comparison was performed by standardizing the measured activities to the same celestine volume, which has been determined by performing a threshold on SEM grey level images to assess to the celestine surface and using Geant4 Monte Carlo simulation toolkit to assess to the emission depth of the particles in celestine. A very good linear correlation between gamma activity and alpha counting from autoradiographs is obtained for all the samples, demonstrating the ability of BeaQuant™ to quantify 226Ra in any points of the millimetric section samples, at a resolution of 20 μm.
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Affiliation(s)
- Sophie Billon
- ERM Company, 4 rue Carol Heitz, 86000, Poitiers, France.
| | - Paul Sardini
- University of Poitiers, UMR 7285, IC2MP, rue Michel Brunet, Bat. 35, Poitiers Cedex 9, 86073, France
| | - Axel Angileri
- University of Poitiers, UMR 7285, IC2MP, rue Michel Brunet, Bat. 35, Poitiers Cedex 9, 86073, France
| | - Catherine Beaucaire
- DEN-Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
| | | | - Marja Siitari-Kauppi
- University of Helsinki, Department of Chemistry, P.O. Box 55, 00014, University of Helsinki, Finland
| | - Michael Descostes
- ORANO Mining- R&D Dpt, Tour AREVA, 1 Place Jean Millier, 92084, Paris La Défense, France
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Reinoso-Maset E, Perdrial N, Steefel CI, Um W, Chorover J, O'Day PA. Dissolved Carbonate and pH Control the Dissolution of Uranyl Phosphate Minerals in Flow-Through Porous Media. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:6031-6042. [PMID: 32364719 DOI: 10.1021/acs.est.9b06448] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Uranyl phosphate minerals represent an important secondary source of uranium release at contaminated sites. In flow-through column experiments with background porewater (BPW) of typical freshwater aquifer composition (pH 7.0, ∼0.2 mM total carbonate (TC)), dissolution of K-ankoleite (KUO2PO4·3H2O), Na-autunite (NaUO2PO4·3H2O), and Ca-autunite (Ca(UO2)2(PO4)2·6H2O) was controlled by mineral solubility at steady-state U release. Effluent concentrations indicated exchange with BPW cations, and postreaction characterization showed alteration of the initial mineral composition, changes in structure (decreased crystallinity, increased disorder, and distortion of U-P mineral sheets) and possible neoformation of phases of similar structure. Increasing the BPW pH and TC to 8.1-8.2 and 2.2-3.7 mM, respectively, resulted in mineral undersaturation and produced ca. 2 orders-of-magnitude higher U and P release without reaching steady state. Minerals incorporated less BPW cations into their structures compared to low carbonate BPW experiments but showed structural disorder and distortion. Faster dissolution rates were attributed to the formation of binary and ternary uranyl carbonate complexes that accelerate the rate-determining step of uranyl detachment from the uranyl-phosphate layered structure. Calculated dissolution rates (log Rs between -8.95 and -10.32 mol m-2 s-1), accounting for reaction and transport in porous media, were similar to dissolution rates of other classes of uranyl minerals. In undersaturated solutions, dissolution rates for uranyl phosphate, oxyhydroxide, and silicate minerals can be predicted within 1-2 orders-of-magnitude from pH ∼5-10 on the basis of pH/carbonate concentration.
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Affiliation(s)
- Estela Reinoso-Maset
- Sierra Nevada Research Institute, University of California Merced, 5200 North Lake Road, Merced, California 95343, United States
- Centre for Environmental Radioactivity CoE, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, 1432 Aas, Norway
| | - Nicolas Perdrial
- Department of Geology, University of Vermont, 180 Colchester Avenue, Burlignton, Vermont 05405, United States
| | - Carl I Steefel
- Energy Geosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, M.S. 74R316C, Berkeley, California 94720, United States
| | - Wooyong Um
- Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P7-54, Richland, Washington 99354, United States
- Division of Advanced Nuclear Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea
| | - Jon Chorover
- Department of Environmental Science, University of Arizona, 177 East Fourth Street, Tucson, Arizona 85721, United States
| | - Peggy A O'Day
- Sierra Nevada Research Institute, University of California Merced, 5200 North Lake Road, Merced, California 95343, United States
- Life and Environmental Sciences Department, School of Natural Sciences, University of California Merced, 5200 North Lake Road, Merced, California 95343, United States
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Spatial variability and radiation assessment of the radionuclides in soils and sediments around a uranium tailings reservoir, south of China. J Radioanal Nucl Chem 2020. [DOI: 10.1007/s10967-020-07077-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Mapping 238U decay chain equilibrium state in thin sections of geo-materials by digital autoradiography and microprobe analysis. Appl Radiat Isot 2018; 140:228-237. [DOI: 10.1016/j.apradiso.2018.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 04/27/2018] [Accepted: 06/22/2018] [Indexed: 11/23/2022]
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Feasibility of Recycling Ultrafine Leaching Residue by Backfill: Experimental and CFD Approaches. MINERALS 2017. [DOI: 10.3390/min7040054] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Reinoso-Maset E, Ly J. Study of uranium(VI) and radium(II) sorption at trace level on kaolinite using a multisite ion exchange model. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 157:136-148. [PMID: 27077702 DOI: 10.1016/j.jenvrad.2016.03.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 06/05/2023]
Abstract
Uranium and the long-lived decay product radium-226 are abundantly present in mine wastes produced during uranium extraction activities. In the case of release to the surrounding environment, these radionuclides are at trace level compared to groundwater solutes, and the presence, content and properties of clay minerals in the host environment influence the extent of radionuclide sorption and, in turn, migration. Since clays are known to have the distinctive property of retaining ions, the aim of this work was to study the sorption of trace U(VI) and Ra(II) on a common phyllosilicate mineral, kaolinite, in the presence of excess K, a common groundwater cation, in order to obtain a thermodynamic database that describes the ion exchange equilibria occurring at the mineral-solution interface. Following a detailed experimental protocol using chemical and radiochemical analytical techniques, batch experiments over a wide pH range (from 2 to 11) and fixed concentration (ca. 10(-9) M), and additional adsorption isotherms at two different solution pH (6.2 and 10.4) over a concentration range (10(-10) to 10(-4) M) were carried out to measure the distribution coefficient (Kd) of U(VI) and Ra(II) sorption on kaolinite. The experimental sorption data was processed according to a general multisite sorbent/multispecies sorbate ion exchange model, which allowed deducing the charge of adsorbed species and the stoichiometry of the associated adsorption equilibria on kaolinite's surface sites. Aqueous speciation calculations predicted Ra(II) as Ra(2+) over the working pH range, and its adsorption curves and isotherms were explained using three sorption sites. Adsorption of U(VI) occurred on four sorption sites and was governed by its solution speciation, with positively charged hydroxylated (UO2(2+) and UO2(OH)(+)) and silicate (UO2(H3SiO4)(+)) species being adsorbed between pH 2 and 6, whereas its negatively charged forms (UO2(OH)3(-) and UO2(OH)4(2-)) dominated U(VI) sorption at pH > 7. Nonlinear fitting of the experimental data using the ion exchange model provided the associated equilibrium constants as corrected selectivity coefficients.
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Affiliation(s)
- Estela Reinoso-Maset
- DEN-Service d'Étude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.
| | - Jacques Ly
- DEN-Service d'Étude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
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