Miners will extract traces of lithium left over in two worked-out tantalum mines in the southeastern Brazilian state of Minas Gerais and export the lithium to China, Agência Brasil reports.

The Brazilian state-run news agency says all the lithium extracted in the first three years is due to be exported to China.

The report quotes Flávio Mota, an executive of the Brazilian state-run development bank, BNDES, as saying he expects the old mines to produce 90,000 tonnes of lithium a year, increasing tenfold the Brazilian output of the metal.

BNDES is investing 221 million reais (about US$45.5 million) in the project.

The venture will entail the removal of mine-tailing ponds, so reducing the danger to people living nearby, and will exploit renewable sources of energy, Agência Brasil says.