Assessing the rare earth element potential of coal ash from Poplar River, Saskatchewan

Coal combustion by-products (CCBs) could be an important new source of rare earth elements (REE) which are required in clean energy technologies. While REE abundances in CCBs have been increasingly characterized, the total tonnage and value of REE remains largely unquantified. Focusing on the western Canadian province of Saskatchewan as a case study, this work estimates that CCBs in ash lagoons from the Poplar River Power Station contain 8.12 million kg REE and 8.58 million kg REE+Sc, with an estimated value of $226 million and $517 million, respectively, based on 2025 REE prices. Although the value per tonne is modest, the volume of REE may be able to satisfy Canada's import requirements for the next 15 years. Along with providing a domestic REE supply, there are advantages to recovering REE from CCBs including existing infrastructure, reduced permitting and environmental requirements, and lower environmental impacts compared to a traditional mine. However, economic and technical challenges exist, including low grades and underdeveloped extraction processes. Nevertheless, quantifying the tonnage and value of REE in waste streams such as CCBs is important for identifying potential mineral resources and justifying further research and investment into developing recovery technologies. As many nations around the world aim to meet their climate change goals, recovering metals from waste streams like CCBs may play an important role in meeting the mineral demands of the energy transition.