US fed investment in Australian rare earth mines was announced this year. I'm unsure if it's more than loan guarantees and a purchase agreement. There was discussion of a floor price but it focussed on the distorting qualities.
https://www.iluka.com/products-markets/rare-earth-products/
Not sure about Lynas and whether they have access to those rare earths from an alternate source to feed into their plant. The Mt Weld mine is carbonatite and mostly LRE rather than the Yytrium and Erbium heavy xenotime/monazite Iluka have stockpiled.