Brazil is well placed in the race for strategic minerals, according to Brazil Geological Survey

"Brazil finds itself in a privileged position in the race for strategic minerals," says Valdir Silveira, the director of geology and mineral resources at the Brazil Geological Survey, still generally known by the extended acronym SGB-CPRM.

Brazil owes its advantage, Silveira says, to "its impressive geological diversity. The present moment affords a unique opportunity, he says, for the country to enlarge its market share, particularly in lithium, graphite, rare earth elements, copper, and nickel."

Lithium is a case in point, he says. The Jequitinhonha River Valley, in the northeast of Minas Gerais, "is outstanding for the size and number of its deposits, while other promising areas such as the Borborema province, particularly the Seridó region [in Rio Grande do Norte], have the potential to assure Brazil of a place among the world's leading lithium producers."

The Brazil Geological Survey's mapping shows that, in Brazil, lithium occurs in pegmatite deposits of the LCT type (lithium-cesium-tantalum), in which the predominant mineral is spodumene, followed by ambligonite, petalite, and lepidolite. At this moment Minas Gerais is the state hosting the largest lithium projects, but there are other areas with great potential as well, particularly in three northeastern states, Ceará, Rio Grande do Norte, and Paraíba, where more than a hundred pegmatite bodies with lithium content have been identified. And then there are greenfield areas along both sides of the Goiás-Tocantins state line, and in some parts of the Borborema pegmatite province in Rio Grande do Norte, where new targets for lithium mineralization have been identified. Two other projects are now under way, one in the east of Minas Gerais and the other in the Solonópole province in Ceará.

In addition to lithium, Silveira notes, there are new potential areas for other minerals essential for the energy transi- tion, such as copper, nickel, tantalum, REEs, and others, including the Tapajós, Alta Floresta, Juma, Nova Brasilândia, and Seridó provinces and the Goiás Magmatic Arc.

Brazil also has great potential as a graphite producer, Silveira says. Graphite now finds a growing number of applications in several industries, such as batteries and electronic components. Graphite occurrences are concentrated in the states of Minas Gerais and Bahia, one of the most promising regions for graphite production worldwide. These occurrences are mainly confined to metamorphosed environments, he says, with metamorphism being considered the first variable in the analysis of graphite potential, as it regulates the degree of crystallization and the ore content.

He is confident that, in the long term, Brazil will attract investments in graphite exploration and strengthen its position as the world's third largest graphite producer, and the second largest producer of graphite flakes used in electric vehicles.

Brazil also has the potential to become an important producer of rare earth elements (REEs). It holds the third largest known reserve in the world, estimated at 21 million tons, according to the Geological Survey, but Silveira notes that the true figure could be much larger, a possibility that is emerging from the mineral exploration programs now being carried out by companies.

Most of the REE reserves in Brazil are located in alkaline-carbonatite rocks, such as those found in six places, among others: three in Minas Gerais (Araxá, Poços de Caldas, and Tapira), two in the state of São Paulo (Jacupiranga and Itapirapuã), and Catalão in Goiás.

REEs are also present in granites, for example at Pitinga in Amazonas and at Minaçu and Montivirío do Norte in Goiás. To a lesser extent, they occur in sedimentary deposits in the São Gonçalo do Sapucaí region in Minas Gerais and São Francisco do Itabapoana in the state of Rio de Janeiro. Studies had been started in the Seis Lagos region in Amazonas and the Serra do Repartimento in the neighbouring state of Roraima, but in both cases they had to be halted because they are in environmental preservation areas.

Despite the great potential for producing these minerals, Brazil still faces challenges, in the short and medium term, which Silveira lists as "expanding our nationwide geological knowledge, based on geological mapping and geophysical, geochemical, and mineral resource surveys, in regions with a smaller scale of geological knowledge, especially in the Amazon region, in the domains of the Amazon Craton and the Guiana Shield.

"In mature and emerging mineral provinces with recognized mineral potential," he adds, "we have acted to expand our knowledge of mineral systems, seeking to improve metallogenetic models, especially with work focused on the analysis of mineral potential through the generation of favorability maps, the acquisition of new geophysical data, and the use of artificial intelligence tools. In 2024, the SGB intends to resume a series of high-resolution aerial geophysical surveys, to fully cover the entire crystalline basement of the country. At the same time, other aerial surveys will use new methodologies, such as electromagnetics, in selected mineral provinces."

The SGB has been a pioneer, Silveira says, in providing information on the Brazilian potential for lithium-bearing minerals and rare earths, in the form of several projects published over the years, including the Lithium Potential Assessment project. In 2016 it published a report on the lithium potential of the Jequitinhonha River Valley and in 2022 a report on the Borborema Province. These publications — and other work on lithium carried out by the SGB — can be accessed at https://www.sgb.gov.br/litio/

On the subject of rare earths, the SGB also conducted a Rare Earth Potential Assessment, publishing its findings in 2015. This was followed by a number of more detailed studies, Silveira says, such as one on Seis Lagos in the state of Amazonas, published in 2016, and a prospectivity map of the Goiás tin-bearing province (2023).