Radionuclide Fate and Transport Modeling for Uranium Mine Operations A GoldSim model was developed to simulate the fate and transport of radionuclides from a uranium mining facility. The purpose of the model was to assess the impact of a proposed tailing disposal facility on groundwater conditions, including the development of a conceptual hydrogeological model and the completion of detailed calculations and modeling to assess the performance of the proposed disposal scheme. GoldSim was used in conjunction with 3-D numerical groundwater flow models to complete the detailed solute transport calculations. Groundwater flow directions and rates were established with the 3-D numerical model while GoldSim was used to complete the solute transport calculations. GoldSim efficiently integrated the results of geochemical modelling for the tailings and waste rock source terms with the hydrological and hydrogeological systems surrounding the site. From the early phases of the project through detailed technical studies and ultimately to final refinement of the project proposal, GoldSim was used extensively to assess the performance of the facility (relative to regulatory water quality criteria) and direct alternative engineering designs for tailings and waste rock management at closure.