From a S.H. site (Whaspe posted it)
On Jack Lifton and Gareth Hatch's website there is a review of a new way to compare rare earth deposits. It was published by a Russian geologist, Dr. Vladimir Seredin. I recommend checking it out.
http://www.techmetalsresearch.com/2010/11/review-of-a-proposed-new-method-for-evaluating-rare-earth-deposits/
As the initial analysis didn't include Bokan, Dr. Seredin has commented on the website as follows:
"Bokan deposit (Ucore) that is not presented on my diagramme, apparently, occupies third place in the world on quality of ores (after Douglas River and Abramovka properties). REEdef in Bokan’s ores (Hole LM08-32, thickness-6.25 m) is 80.4 %, and Koutl is equal 5.5. Unfortunately I have met with the data after finishing the paper preparation."