%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Boekhout, F.
%A Gérard, Martine
%A Kanzari, A.
%A Michel, A.
%A Déjeant, A.
%A Galoisy, L.
%A Calas, G.
%A Descostes, M.
%T Uranium migration and retention during weathering of a granitic waste rock pile
%D 2015
%L fdi:010064187
%G ENG
%J Applied Geochemistry
%@ 0883-2927
%K FRANCE
%M ISI:000354284000011
%P 123-135
%R 10.1016/j.apgeochem.2015.02.012
%U https://www.documentation.ird.fr/hor/fdi:010064187
%> https://www.documentation.ird.fr/intranet/publi/2015/06/010064187.pdf
%V 58
%W Horizon (IRD)
%X This study investigates the post-mining evolution of S-type granitic waste rocks around a former uranium mine, Vieilles Sagnes (Haute Vienne, NW Massif Central, France). This mine was operated between 1957 and 1965 in the La Crouzille former world-class uranium mining district and is representative of intragranitic vein-type deposits. 50 years after mine closure and the construction and subsequent re-vegetation of the granitic waste rock pile, we evaluate the environmental evolution of the rock pile, including rock alteration, neo-formation of U-bearing phases during weathering, and U migration. Vertical trenches have been excavated through the rock pile down to an underlying paleo-soil, allowing the investigation of the vertical differentiation of the rock pile and its influence on water pathways, weathering processes and U migration and retention. Arenization dominantly drives liberation of U, by dissolution of uraninite inclusions in the most alterable granitic minerals (i.e. K-feldspar and biotite). Retention of U in the matrix at the base of the waste rock pile, and in the underlying paleo-soil most likely occurs by precipitation of (nano-) uranyl phosphates or a combination of co-precipitation and adsorption reactions of U onto Fe (oxy) hydroxides and/or clay minerals. Even though U-migration was observed, U is retained in stable secondary mineral phases, provided the current conditions will not be modified.
%$ 064