Economic aspects of carbonatites of India

Among the 20 carbonatite-alkaline rock associations known from India, eight contain economic deposits that are either being presently exploited or lik ely to become workable resources. These include deposits of fluorite (Ambad ongar, Gujarat), apatite, (Newania, Rajasthan; Kutni and Beldih, West Benga l) and vermiculite (Sevattur, Tamil Nadu). Carbonatite complexes of Sevattu r, Sung Valley and Samchampi hold considerable potential for Nb, P, and Fe. The Samchampi Complex, Assam contains an estimated reserve of some 300 mil lion tons of hematite ore, besides Nb (10,970 tons), Ta (3740 tons), Y (189 4 tons) and apatite (10 million tons of ore with 35% P2O5) and thus appears to be the most promising complex among the new discoveries. Recovery of py rochlore +/- apatite, magnetite, zircon, and monazite have been evaluated f or the soils at Sevattur, Sung Valley and Samchampi. A variety of elements either alone or in combination such as REE, Ba, Sr, V, Ti, Zr, Th, and U co uld become important co-products from these complexes. (C) 2000 Elsevier Sc ience Ltd. All rights reserved.