Distribution of arsenic and nickel in uranium mill tailings, Rabbit Lake, Saskatchewan, Canada

Effect of biogeochemical redox processes on the fate and transport of As and U at an abandoned uranium mine site: an X-ray absorption spectroscopy study

“…[37,42] Arsenic was also found to be adsorbed to ferrihydrite resulting in long-term stability under site conditions, preventing aqueous As transport. [37,43,44] The majority of these studies have focussed on the geochemistry and stability of U or As in tailing piles rather than physical and chemical controls on down-gradient transport of both elements in the same study.…”

Microscale mineralogical characterization of As, Fe, and Ni in uranium mine tailings

“…Mines in this basin produce 29 percent of the world's uranium; with ore grades up to 21 wt% (average of 15 wt%) (Jamieson and Frost, 1997). Uranium tailings typically contain elevated concentrations of dissolved contaminants that exceed health standards (Morrison and Cahn, 1991;Somot et al, 1997;Donahue et al, 2000;Abdelouas, 2006). These contaminants include arsenic and nickel.…”

Precipitation of aluminum and magnesium secondary minerals from uranium mill raffinate (pH 1.0–10.5) and their controls on aqueous contaminants

“…2h) show that the removal of Ni increases in the absence of Fe (31.5% and 21.0% Ni removed at pH 4.0 for R3 and R4, respectively). Previous studies suggest that Ni sequestration in lime neutralized U tailings is controlled by Ni(OH) 2 and NiMoO 4 precipitation and adsorption to ferrihydrite (Donahue et al, 2000;Essilfie-Dughan et al, 2012, 2011Mahoney et al, 2007). The previous mineralogical characterization suggests Ni adsorption by amorphous AlOHSO 4 (R3) and AleFe(OH) 3 (R4).…”

“…This is often performed through bulk neutralization using slaked lime (hydrated CaO) to increase the pH in a stepwise manner to induce mineral precipitation reactions. This milling and treatment process is used in many U mills in northern Saskatchewan, Canada, all of which process ore mined from the high grade U deposits in the Athabasca basin (Bharadwaj and Moldovan, 2005;Donahue et al, 2000;Langmuir et al, 1999;Mahoney et al, 2007;Moldovan et al, 2003). Many studies have identified various mechanisms of EOC sequestration and the subsequent mineralogy of U tailings generated by similar neutralization processes at numerous sites (Douglas et al, 2010;Essilfie-Dughan et al, 2012;Mahoney et al, 2007;Moldovan et al, 2003;Schindler et al, 2015Schindler et al, , 2013; and references therein).…”