Radiation protection strategies in high-grade underground uranium mines

Mining high-grade uranium ore in an underground environment presents a number of potential challenges and exposure sources that must be addressed and controlled. Specific sources include radon progeny, gamma, and long-lived radioactive dust (LLRD). Workplace conditions, including grade and proximity to ore, worker positioning, and shielding impact gamma exposure potential, while ground conditions and the presence of radon gas in water can create highly temporal and spatially variable radon progeny conditions. High-grade uranium ore grade also presents a strong source term for LLRD that must be controlled. Cameco has implemented numerous physical and administrative control strategies in an integrated fashion to address these hazards. These controls start at the design of the mine and extend into operational practices. The radiation protection program provides the overall framework that guides the various activities including training of workers and radiation protection staff, dosimetry and engineering monitoring programs, research into better characterisation of hazards, shielding design and administrative controls. Cameco has continued to optimise radiation protection strategies in high-grade underground uranium mining environments over the past two decades and has kept doses well below the national dose limits and implemented numerous ALARA initiatives to further lower doses where practical.