NIOBIUM (COLUMBIUM) AND TANTALUM 



451 



Table 90. — Conditional resources of niobium and tantalum 



not profitably recoverable 



nth existing technology and 



Type of 

 deposit 



Grade 

 (percent) 



54,000,000 

 12,000,000 



North America (United States) : 



Bauxite deposits, Arkansas Byproduct 



potential. 



Magnet Cove, Ark Carbonatite - 



Africa : 



Nigeria: Jos Plateau O 



Malawi: Chilwa Island Residual Several million 



material. 



Other :^ South America, Africa, 



Asia, and Europe. 



0.05-0.15 

 .08 



55,100 

 10,000 



.21 



Several-thousand Several-thousand 



Table 91. — Unevaluated resources of niobium and tantalum 



Locality Type of 



deposit 



North America (United States) : 



Gem Park, Colo Carbonatite. 



Potash Sulfur Springs, Ark Do. 



Rocky Boy, Mont Do. 



Europe: 



Finland: Sokli Do. 



Portugal (tin-tantalite) Pegmatite and 



placers. 

 Africa ; 



Tanzania: Oldonyo Dili Carbonatite. 



North Rhodesia: 



Feira District Do. 



Nkumbwa Hill Do. 



South Rhodesia: 



Bikita Pegmatites. 



Darowa Carbonatite. 



Gabon: Columbite-tantalite Pegmatites. 



South West Africa : 



Orange River area Do. 



Karabib-Omaruru area Do. 



Zambia : 



Nkombwa Carbonatite. 



Kaluwe Do. 



Malagasy Republic Pegmatite. 



Mozambique Do. 



Republic of South Africa: Glenover __ Carbonatite. 

 Asia: 



Malaya Pegmatites and 



placers. 



Thailand: Phang Ngo Placer. 



India: Ambadongar Carbonatite. 



Australia: Western Australia Pegmatites and 



^ placers. 



sources of these elements in the United States are 

 relatively small. The United States as a major con- 

 sumer of these elements must therefore look to 

 these foreign sources for its present and near-future 

 supply. 



In the past, small amounts of niobium and tanta- 

 lum were produced from the numerous pegmatite 

 districts in the United States, commonly as byprod- 

 ucts of mining for mica, beryl, and lithium minerals. 

 This small and erratic source of niobium and tanta- 

 lum is rather insignificant when compared to the 

 large pyrochlore deposits now supplying most of the 

 niobium markets. 



The most significant resources of niobium in the 



United States are contained in carbonatites at Iron 

 Hill and Gem Park, Colo.; Rocky Boy, Mont.; and 

 Magnet Cove and Potash Sulfur Springs, Ark.; in 

 euxenite placer deposits at Bear Valley, Idaho; and 

 in the bauxite deposits of Arkansas. Minor tantalum 

 resources are also contained in the placer deposits 

 of Bear Valley, Idaho, and in pegmatites widely dis- 

 tributed in the United States but especially at the 

 Harding mine, N. Mex. 



Three of the carbonatites are not sufficiently ex- 

 plored to be included in the computation of reserves, 

 and one (Magnet Cove) is of lower grade than that 

 of deposits now considered minable. The Arkansas 

 bauxite deposits contain 0.05-0.15 percent NbaOs 

 and constitute a major potential resource, but re- 

 covery of the niobium, although it can be made 

 during the processing of the bauxite, is unprofitable 

 under present market conditions. 



At least half of the evaluated domestic deposits, 

 therefore, are of much lower grade than those con- 

 sidered as commercial sources and must be classed 

 as resources rather than reserves. Such deposits, 

 however, remain strategically important and could 

 be utilized in times of national emergency. 



Distinction between world deposits that constitute 

 reserves and those that are conditional resources 

 cannot be made on a strict tonnage and grade basis. 

 Deposits shown as reserves (table 89) include some 

 which are now being mined as well as others which 

 would appear to be minable but which are not now 

 competitive with the larger and richer deposits. The 

 resources shown in table 90 are largely carbonatites 

 that are known to contain niobium minerals but are 

 otherwise unevaluated. Also listed in table 90 are 

 some evaluated deposits of grade of 0.2 percent or 

 below, which are considered subeconomic at the 

 present time. 



The identified resources of niobium and tantalum 

 of the world (exclusive of U.S.S.R. and Iron Curtain 

 countries) are summarized in table 92. 



