That is awesome! I knew that China had control over the worlds rare earth production and that concerned me but this find in the Mojave Desert sounds like a God Send. One thing that uses a lot of rare earth material would be super magnets. I have been collecting them for some time and to get the cheapest prices you need to find an independent supplier who buys them in bulk from China.
With a mother load of rare earths in the USA we could more cheaply build a magnetically levitating super-train system.
I agree it is a nice thing to have found to reduced reliance on China. As far as being cheaper I am willing to bet American labor costs for refining will far surpass the costs of China's final products. Besides is the States going to under cut the market I highly doubt that more like try to find out how to jack it up even higher.