Carbonatites, uranium deposits

Reserves Large resources of yttrium in monazite and xenotime are available worldwide in ancient and recent placer deposits, carbonatites, uranium ores, and weathered clay deposits (ion-adsorption ore). Additional large subeccaiomic resources of yttrium occur in apatite-magnetite rocks, deposits of niobium-tantalum minerals, nonplacer monazite-bearing deposits, sedimentary phosphate deposits, and uranium ores. The world s resources of yttrium are probably very large [39]. 

Most carbonatites contain insufficient uranium to constitute a minable uranium deposit, but some are mined for other minerals and uranium is recovered as a co- or by-product. Valuable elements contained in, or associated with, carbonatites include Cu (Palabora, South Africa), REE (Mountain Pass, U.S.A., and Araxa, Brazil), Nb (Araxa, others in Brazil, Africa, Canada and the U.S.A.), Th (Wet Mountains, U.S.A.), Ta (U.S.S.R.) and V (Magnet Cove, U.S.A.). 

Intrusive Deposits. Deposits included in the intmsive deposit type are those associated with intmsive or anatectic rocks of different chemical composition, eg, alaskite, granite, monzonite, peralkaline syenite, carbonatite, and pegmatite. Examples include the uranium occurrences in the porphyry copper deposits such as Bingham Canyon and Twin Butte in the United States, the Rossing Deposit in Namibia, and Ilimaussaq deposit in Greenland, Palabora in South Africa, and the deposits in the Bancroft area, Canada (15). 

Besides the conventional uranium resources, there are also the so-called unconventional uranium resources , which are defined as deposits with very low uranium content, from which uranium is typically only recoverable as a minor by-product. These unconventional uranium resources are obtained from the extraction of phosphates, non-ferrous ores and carbonatites, as well as black schist and lignite. It has to be noted that the distinction between conventional and unconventional resources is not entirely clear cut, but is, instead, somewhat transitional. 

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