| Titre | Characterization of Uranium and Rare Earth Element mobility downstream of a tailings impoundment near Bancroft, Ontario |
| Auteur | Laidlow, A; Parsons, M; Jamieson, H |
| Source | Proceedings of the 10th International Conference on Acid Rock Drainage (ICARD) and International Mine Water Association (IMWA) Conference; 2015 p. 1-10 |
| Liens | Online - En ligne
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| Année | 2015 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20140272 |
| Réunion | 10th International Conference on Acid Rock Drainage (ICARD) and International Mine Water Association (IMWA), 2015 Conference; Santiago; CL; avril 21-24, 2015 |
| Document | livre |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Ontario |
| SNRC | 31F/04 |
| Lat/Long OENS | -78.0000 -77.5000 45.2500 45.0000 |
| Sujets | Archéen; ceintures de roche verte; résidus; géochimie des résidus; analyses des résidus; uranium; terres rares; géochimie des terres rares; contamination des métaux lourds; substances polluantes;
diffraction des rayons x; analyses par diffraction des rayons x; pétrographie; géologie de l'environnement; géochimie |
| Illustrations | location maps; plots; pie charts |
| |
| Programme | Outils d'adaptation et d'impacts sur l'environnement pour les mines de métaux, Géosciences environnementales |
| Résumé | (disponible en anglais seulement)
Attenuation of uranium (U) and rare earth elements (REEs) has been observed in stream and wetland sediments, but the geochemical and mineralogical processes
involved in sequestering these elements in natural systems are not fully understood. The decommissioned Bicroft Uranium Mine near Bancroft, ON, operated from 1957 to 1963, and processed approximately 2,284,421 tonnes of low-grade, disseminated U ore
hosted by pegmatite dykes in amphibolite gneiss. During operations, the mine used two tailings impoundments and a modified stream and wetland system to reduce the concentrations of U, other metals, and radionuclides in tailings effluent to levels
below the Provincial Water Quality Objectives. Since mine closure, the streams and wetland have continued to operate as a passive treatment system for tailings effluent, demonstrating the potential viability and longevity of natural attenuation to
sequester U and REEs. In this study, we used tangential flow filtration, ICP-ES/MS, scanning electron microscopy, and synchrotron techniques (bulk- and micro-XANES, -XRF, and -XRD) to characterize processes controlling U and REE mobility and
attenuation in tailings, sediment, and colloid samples. Results of this study indicate that Fe- and Mn-(oxyhydr)oxides, including goethite [?-FeO(OH)] and birnessite (?-MnO2), are the main mineral hosts for U and REEs in colloids and sediments. In
addition, detrital grains of U- and REE-bearing minerals were found >200 m downstream in colloids and sediments, showing the potential for long-range transport of colloids and fine particulates in the stream system. While natural attenuation exhibits
great potential to reduce U- and REE- concentrations, seasonal influences on the stability of trace metals in sediments were observed and may demonstrate the limitations of streams and wetlands as a viable method of attenuation. The results of this
study are intended to aid development of more effective passive treatment systems and improve environmental monitoring strategies for U and REEs. |
| Résumé | (Résumé en langage clair et simple, non publié)
Les rejets d'uranium (U) et de terres rares (TER) des résidus miniers dans les eaux de surface touchent la qualité des eaux, la santé humaine, les
organismes et le proche environnement. Cette étude utilise de nouvelles méthodes de filtration des eaux de surface et des analyses minéralogiques à la fine pointe pour caractériser les processus clés qui contrôlent les rejets, le transport et le
destin de l'U et des TER des résidus de la mine d'U abandonnée de Bancroft en Ontario. Les résultats de cette recherche aideront à développer des systèmes de traitement des eaux et de meilleures stratégies de suivi environnemental pour de futurs
développements de l'U et des TER. |
| GEOSCAN ID | 295478 |
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