Questions regarding exhaustible resource supply are best posed in terms of how extraction costs and prices will evolve as lower quality resources are exploited. To address such questions in the context of uranium the authors develop a model of long-run cost dynamics which (1) builds on a classic model of declining uranium ore grades, (2) includes both new and existing parameterizations of extraction cost structures, (3) incorporates the extraction cost impacts of learning and productivity growth, and (4) is driven by the IAEA's most recent uranium demand projection. The authors emphasize the importance of allowing interaction between temporal versus cumulative cost mitigating processes (productivity growth and learning respectively) and such processes' interaction with demand growth profiles. It is demonstrated that - under rather conservative assumptions on the dynamics of these processes - the rate of increase of uranium extraction costs is significantly attenuated relative to that which might otherwise occur. Indeed in some cases - again, for rather conservative assumptions on productivity growth and learning - it may not be unreasonable to anticipate that such costs may decline (as have those of several commodities over the past century). The policy implications of such attenuated - or even declining - uranium costs are significant. (C) 2014 International Atomic Energy Agency. Published by Elsevier Ltd. All rights reserved.