U.S. Critical Mineral Security Cannot Rely On Mine Waste Alone

Policymakers are increasingly emphasizing secure critical mineral supplies for clean energy development and U.S. technological competitiveness. Thanks to claims that the U.S. already mines all that it needs, recovery of critical minerals from mine waste has emerged as a policy priority. However, critical mineral policy built on misperceptions that waste recovery can eliminate the need for conventional mines risks deepening mineral import dependence by devaluing support for new mine projects.

Waste recovery offers valuable opportunities for mineral production, but remains unproven for the vast majority of critical minerals. Of the 60 elements on the critical mineral list, only a few—such as gallium, germanium, and tellurium—are demonstrably extracted from mine waste. A handful more possess promising potential for waste recovery based on geologic correlations, like rare earth elements in iron ore.

Studies that tally trace amounts of critical minerals in mine tailings imply tantalizing theoretical volumes. Yet, most of these samples consist of low-grade material that remains uneconomic to recover. The disappointing reality is merely that every rock contains a little of every element—no different than garden soil.

The U.S. cannot rely solely on uncertain recovery pathways that may never materialize or that may only meet a small fraction of national demands. Waste recovery must therefore expand in parallel with policies to support new conventional mining, as one component of a comprehensive strategy. Ultimately, feasible waste recovery will vary mineral by mineral, and site by site. Even then, production from mine waste may only prove practical under exceptionally high prices. Mine waste initiatives must therefore prioritize critical minerals with:

• 1. existing and proven recovery techniques;

• 2. potential for economically favorable production; and

• 3. ability to supply minerals at a meaningful scale.