Announcements of new rare earth deposits outside China arrive regularly. Announcements of new heavy rare earth separation capacity do not. Separation of dysprosium and terbium requires hundreds of solvent extraction stages, specialised reagent handling and operators with decades of tacit process knowledge.
Until that capacity exists at scale outside China, a non-Chinese magnet supply chain remains partial: ore can be mined in Australia or the United States, but the elements that make a magnet survive a hot motor still pass through a small number of facilities in a single country.
The practical implication for buyers is that qualifying an alternative supplier is a multi-year process measured in metallurgy, not in contracts.