Processing is the thing china does, you don't really mine rare earths, they are in many areas. Sure there are substrates it's easier to extract from, but the massive pollution of the processing that china was willing to accept when others were not that allowed them to corner the market. It can be done more cleanly, the US has some processing for strategic reasons (not enough though), but doing it clean is _very_ expensive. Lets hope the people modifying plants to concentrate elements make work.