Uranová ložiska Brazílie

 

Brazil holds one of the world largest uranium reserves worlwide, which cover the supply of domestic needs on the long run and oversupply will be available for the international market. In July/2001 the Country registered the sixth largest uranium geological reserve in the world. With circa 309.000t of U3O8 in the States of Bahia, Ceará, Paraná and Minas Gerais, among other locations.

Prospecting studies and geological researches were carried out in only 25% of the national territory. . The country also holds uranium occurences associated to other minerals as those found in the Pitinga Deposit, in the Amazonas State and in Carajás, in the Pará State. There are about additional 150,000 tons of uranium oxide estimated for these areas.

Brazil has nowadays, the world's 6th largest uranium geological reserve.

The Brazilian geological reserves increased from 9.400tons, known in 1975, to the current amount, which can be expanded with new prospecting works and mineral research.

The Brazilian Mining Code assigns the following classification to the mineral reserves: inferred reserve, indicated reserve and measured reserve.

Uranium Reserves in Brazil in U₃O₈ tons.

Occurrence	Measured and Indicated			Inferred	TOTAL
Deposit/Mine	< 40US$/kg U	< 80US$/kg U	Sub-Total	< 80US$/kg U
Caldas (MG)		500t	500t	4.000t	4.500t
Lagoa Real/Caetité (BA)	24.200t	69.800t	94.000t	6.770t	100.770t
Itataia (CE)	42.000t	41.000t	83.000t	59.500t	142.500t
Others				61.600t	61.600t
TOTAL	66.200t	111.300t	177.500t	131.870t	309.370t

LAGOA REAL URANIUM DISTRICT

The Uranium District of Lagoa Real is located in a mountainous area in the center-south of the State of Bahia, about 20km northeast from the Caetité Municipality.

It was discovered during a series of aero-geophysical surveys between 1976 and 1977 that led to the identification of 19 mineralized areas. A more detailed work of aerial gamma-ray spectrometry led to the discovery of 33 additional uranium occurrences, also assessed.

The Caetité massif is located in the South part of the Săo Francisco Craton in Bahia. Its length is around 80 km and has a variable width between 30 and 50 km. It is formed by Archean microcline gneisses along with granite, granodiorite, sienite and amphybolite. In the South, East and North there are extensive drawdown areas placed beneath mainly by gneiss and green shales of Archean or Lower Proterozoic age.

The region was also submitted to three Tectonic cycles during which the rocks were rejuvenated. This includes the Guriense (3.000 Ma), Transamazonic (1800-2100 Ma) and Espinhaço/Brasiliano (1800-500 Ma) cycles among which the last one was the most s ignificant in terms of mineralization of Lagoa Real.

The basic mine project was concluded in 1996, indicating an open pit mining in the Cachoeira mine (anomaly 13). This anomaly with an average level of 3.000ppm forecasts a production of around 400 tons/year of uranium. Gradually other deposits will be exploired, among the existing 33 ones. These reserves are sufficient for the operation f ten reactors of the Angra 2 type for the whole working life of the undertaking.

ITATAIA

The Itataia deposit is located in the central part of the State of Ceará, at around 45 km southeast of the city of Santa Quitéria.

The Itataia mine has geological reserves of 142,5 thousand tons of uranium associated with phosphate. The exploitable mine has 79,5 million tons of ore with levels of 11% of P205 and 998 ppm of U₃O₈ , and such ore has 8,9 million tons of P205 and 79,3 million tons of U₃O₈ . In this mine we can also explore circa 300 million mł of marble, totally uranium free.

Located at 212 km from Fortaleza, the region main economic activities are agriculture and cattle raising.

Although it is the largest uranium reserve of our country, its economic viability depends on the exploration of the associated phosphate. This means t hat the extraction of uranium is conditioned to the production of phosphoric acid - an input used in fertilizer production.

ZDROJ:INB