Defence minister says still too few sources of rare earths, page-10

Thats when Moly went bankrupt. Not when it was reopened.

June 16, 2017
The mine, which was the only functioning rare earths mine in the US before it went bankrupt in 2015, went up for auction on Wednesday.
https://www.mining.com/mountain-pass-sells-20-5-million/

Trump had no idea the new owners trying to pursuade him
The head of an advanced-materials manufacturer said he met with President Donald Trump’s chief strategist, Steve Bannon, on Monday to persuade him that the U.S. should nationalize the country’s only mine of rare earth minerals, which are used in military applications.
https://www.bloomberg.com/news/articles/2017-07-18/trump-urged-by-ceo-to-nationalize-the-only-u-s-rare-earths-mine

So when you say
Another great idea from Donald Trump, at least it's only going to cost $200 million to reopen a mine to produce a product at five to ten times it's actual value just to prove a point...hardly an economically viable venture.

Its not accurate at all. The mine opened well before Trump had any interest in it which only arose from the Trade War and not before. Trump had nothing at all to do with the reopening sorry.

He only piped up at this time many years after what you have said.
JULY 23, 2019 / 7:31 AM / A YEAR AGOTrump tells Pentagon to find better sources of rare earth magnet
https://www.reuters.com/article/us-usa-rareearths-trump/trump-tells-pentagon-to-find-better-sources-of-rare-earth-magnet-idUSKCN1UH2L4

Research is the key!