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 likely to become workable resources. These include deposits of fluorite (Ambadongar, Gujarat), apatite, (Newania, Rajasthan; Kutni and Beldih, West Bengal) and vermiculite (Sevattur, Tamil Nadu). Carbonatite complexes of Sevattur, Sung Valley and Samchampi hold considerable potential for Nb, P, and Fe. The Samchampi Complex, Assam contains an estimated reserve of some 300 million tons of hematite ore, besides Nb (10,970 tons), Ta (3740 tons), Y (1894 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 pyrochlore +/- apatite, magnetite, zircon, and monazite have been evaluated for 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 could become important co-products from these complexes. (C) 2000 Elsevier Science Ltd. All rights reserved.