The mining major said a judge had reinstated "the term and validity of the operating licence" and it resumed operations on Thursday.
Brazil's environmental regulator had suspended Onca Puma's licence earlier last week alleging non-compliance.
Meanwhile Vale's Salobo copper mine in Brazil remains suspended after a fire affected a conveyor belt last week.
The company continues to mull the future of its base metals division, having renewed talk of a potential spin-off in April.
CEO Eduardo Bartolomeo told Financial Times' Mining Summit last week the company was not talking about a spin-off near-term and the business had to first "go through an internal transformation", Reuters reported.
Vale's share price has slid along with the drop in iron ore price in recent months but closed up 0.76% in New York on Friday, valuing the company at US$75 billion.