Construction of the Tailings Storage Facility for the Key Lake Project a major uranium mine in northern Saskatchewan, Canada, was completed in June, 1983. Principal design features of the tailings facility are an underseal and underdrainage system over the entire area, systematic deposition of the tailings in thin layers using the sub-aerial technique, and continuous removal and recycling of all surface water and underdrainage outflows to the mill for treatment. These features are designed to achieve a consolidated, drained tailings deposit suitable for immediate decommissioning QD completion of milling, and with a minimal potential of long term seepage. The design has used naturally occurring materials as far as possible, with the underseal constructed by modification of the natural till with imported bentonite. Design requirements, specifications and quality control procedures during construction are described, together with initial deposition of the tailings slurry
