[rpaddock]

"“Rare earths always come mixed together, whether they’re in an ore or in a waste stream..."

What these College level projects never address is real world experience with Thorium. "Mixed together" very often includes Thorium. So as you run your process you either leave be hid a pile of Thorium as you extract what you want, or you end up with a pile of Thorium that you extracted.

While Thorium is useful, as I'd love to have a Thorium powered pebble-bed reactor buried in my backyard to power my house, it will attract government regulators when the pile gets big enough causing no end of expansive paperwork on radiological issues.

This is why places like Coal Mines don't extract the Lithium from the Tailings. They just don't want to deal with the radiological issues.