Re: Medium rare?
It's not so much that processing rare earths is too polluting for the USA but that it's not profitable
They are a minor byproduct of mining other metals, generally Nickel.
So the more nickel you mine (and the more rare-earth rich your ore) the more potential rare earths you have and the cheaper you might be able to obtain them
But then you have to make the decision to perhaps double the cost of your processing plant to extract a tiny % rare earths.
Is this worth it, based on global demand, cost of other suppliers, risk that other suppliers (cough China) could dump stock on the market, current tariffs and sanctions, future tariffs and sanctions...
And you have to do this at an existing mine that might be nearly tapped out with a few years of production left or plan to double the cost, and half the profitability, when making the business case for a new mine