| Abstract Scope |
Demand for rare earth elements (REEs) in energy and defence technologies is rising, underscoring the need for exploring domestic resources, including unconventional sources. Coal ash is abundant, but geographically dispersed, compositionally heterogeneous, and stored across legacy impoundments and landfills, creating challenges for economic REE recovery. Prior studies emphasize resource characterization and plant-level technoeconomics, but the system-level cost drivers of a national supply chain remain underexplored. Here we present a preliminary, scoping analysis that includes a geospatially explicit and basin informed coal-ash database, process mass balances, and technoeconomic data to design a cost optimal supply chain for REE recovery from coal ash. As a counterfactual, we first model a centralized “ship-the-ash” configuration to decompose costs and identify dominant contributors. Even under favourable assumptions (100% REO recovery, full ash saleability, and high Nd/Pr pricing), operating revenues fail to offset costs, with bulk transport of low-grade material emerging as a key cost driver. This outcome demonstrates that transport penalties overwhelm single-stage centralized strategies as large scale ash transport is not economically viable. Consequently, these results motivate a multi stage architecture in which the first pass (beneficiation and/or leaching) occurs on site - ideally with mobile or relocatable units - to reduce transported mass and move higher value intermediates to regional hubs for finishing, which can increase the chances of economic feasibility. |