The discovery of rare earths on a Japanese island is sauced below. Sounds like industrial-scale recovery is very feasible. I'd bet the US could do the same thing given our own vast territorial holdings and Hawaiian locations.
http:// www.foxnews.com/science/2018/04/19/treasure-island-rare-metals-discovery-on-remote-pacific-atoll-is-worth-billions-dollars.html
https:// www.nature.com/articles/s41598-018-23948-5.pdf