This is worth a read for those who haven't seen itWhile researching information on REE exploration and mining and how the deposit is evaluated to see if the deposit is economical, I came accross this article. It's a long read but worth the time. As I find relevant information that may be of help, I will post it for all to see. If there is a problem with this link please let me know. I will do my best to get you to the article.
https://www.theaureport.com/pub/na/ryan-castilloux-sorting-reality-from-hype-in-the-crowded-rare-earth-industry
Have a good day!