I'm new to REE so just been researching what constitutes a...

I'm new to REE so just been researching what constitutes a decent grade (obviously the definition of a decent grade also depends on how easy/cheap it is to extract). And will appreciate more informed feedback on anywhere I have gone wrong.

I knew the Uranium levels were already considered very low at 400ppm (Though the Uranium I suppose is somewhat a bonus if you have decent REE grades). From my findings it would seem the REE concentrations of the Kvanefjeld deposit are very very low at around 1% (10,000ppm). And of that 1% only 3.6% are heavies. By my calculations within the total indicated and inferred resources, heavies are only 0.0392% (392ppm).

My judgement of the grades as being very low comes from the Molycorps Mountain Pass deposit (apparently the largest REE deposit outside China??) where the average cut off grade is over 9%. And information from Namibia Rare Earths inc, which says in Chinas heaviest deposits the % of heavies is in fact larger than the % of lights, i.e. over 50% of the deposit's REE are heavies. (Disclosure: I have no position or relation in any of these companies). I imagine a high grade of TREO can balance out a low level of HREO and vice versa but I am concerned by the fact both Total RE Oxide grade and Heavy RE Oxide grade seem very low.

Page 12 of "Rare Earth Elements: The Global Supply Chain...

"Mountain Pass cut-off grade (below which the deposit may be uneconomic) is, in some parts, 5.0%, while the average
grade is 9.2%. Molycorp anticipates becoming the low cost producer. U.S. Rare Earth (another U.S. based company), in the pre-feasibility stage of mine development, has long-term potential because of its large deposits in Idaho, Colorado, and Montana. Canadian deposits contain the heavy rare earth elements dysprosium, terbium, and europium, which are needed for magnets to operate at high temperatures. Great Western Minerals Group (GWMG) of Canada and Avalon Rare Metals have deposits with an estimated high content (7% and 20% respectively) of heavy rare earth elements."

There will be many people on here who have researched further than me and have a better understanding of this deposit too. Please if you can share your (fact based) knowledge I would be very interested. I am fond of a REE+Uranium play but am just unsure of the feasibility to develop this into a successful mine at such low REE grades.

Sources:
http://www.fas.org/sgp/crs/natsec/R41347.pdf
http://www.namibiarareearths.com/unqiue-project.asp