Mineralogical controls on the long-term stability of arsenic were studied in arsenic-rich uranium mine tailings deposited in the Rabbit Lake in-pit tailings management facility, northern Saskatchewan, Canada. Three-dimensional, reactive multi-component transport modeling of the RLITMF and the surrounding groundwater regime was conducted using geochemical field-based data, synchrotron X-ray absorption studies and laboratory-based diffusion cell experiments to quantify the fate and long-term (10,000 year) transport of arsenic. Results showed that adsorption of arsenic to the tailings and...