Carbonatites of the world, explored deposits of Nb and REE—database and grade and tonnage models / Карбонатиты мира, разведанные месторождения Nb и РЗЭ—база данных и модели сортности и тоннажа

This report is based on published tonnage and grade data on 58 Nb– and rare-earthelement (REE)–bearing carbonatite deposits that are mostly well explored and are partially mined or contain resources of these elements. The deposits represent only a part of the known 527 carbonatites around the world (Woolley and Kjarsgaard, 2008), but they are characterized by reliable quantitative data on ore tonnages and grades of niobium and REE.
Grade and tonnage models are an important component of mineral resource assessments. Carbonatites present one of the main natural sources of niobium and rare-earth elements, the economic importance of which grows consistently. A purpose of this report is to update earlier publications (Singer, 1986a, 1986b, 1998; Orris and Grauch, 2002). New information about known deposits, as well as data on new deposits published during the last decade, are incorporated in the present paper. The compiled database (appendix 1) contains 60 explored Nb– and REE–bearing carbonatite deposits—resources of 55 of these deposits are taken from publications. In the present updated grade-tonnage model we have added 24 deposits comparing with the previous model of Singer (1998). Resources of most deposits are residuum ores in the upper part of carbonatite bodies. <...>