SAO PAULO, July 27 (Reuters) - Brazilian miner Vale SA said on Thursday it reached two separate agreements to sell a 13% stake in its nickel and copper business for $3.4 billion.

Under the deal, a joint venture formed by Saudi Arabian Mining Co (Ma'aden) and the country's Public Investment Fund (PIF) will own 10% of Vale's base metal unit, while investment firm Engine No. 1 will own 3%.

($1 = 4.7515 reais) (Reporting by Peter Frontini; Editing by Isabel Woodford)