(Adds details, Vale comments, evacuation at Arcelor Mittal, Vale port terminal ordered to close)
SAO PAULO, Feb 8 (Reuters) - Brazilian authorities ordered Vale SA to evacuate around 500 people from a dam area at its Gongo Soco mine in the state of Minas Gerais on Friday as a preventive measure, the mining company said.
On Jan. 25, a mine operated by Vale collapsed in the town of Brumadinho in the same state, killing an estimated 300 people in Brazil's deadliest mining disaster ever.
In a separate development on Friday, inhabitants of a city close to another dam in Minas Gerais state, operated by Arcelor Mittal, were also evacuated, firefighters said but did not give details or say why the dam was at risk.
Vale said in a statement that the Brazilian mining agency ordered the evacuation at the dam at Gongo Soco after engineering consultancy Walm said a certificate guaranteeing stability conditions had not been issued for the dam.
Vale said it has intensified inspections in the area and was installing equipment to detect vibrations and bringing in international consultants to assess the situation.
As a security measure, 500 inhabitants of the city of Barão dos Cocais, where the dam is situated, were taken to a gymnasium nearby, the municipality said on its Facebook page.
Also on Friday, authorities closed a port terminal operated by Vale in Vitoria, in the southeastern state of Espirito Santo, due to pollution issues.
The municipality of Vitoria said on Thursday that it had fined the miner 35 million reais ($9.5 million) for throwing mining residues in the sea. Vale said in a statement that it would take appropriate measures but added that recent inspections by local authorities had not detected problems.
In the wake of the Brumadinho mining disaster, the state of Minas Gerais cancelled Vale's license to operate another dam and a mine in the state, as the company has come under intense public pressure following the accident.
On Tuesday Vale declared force majeure on some iron ore contracts after a court-ordered halt to a mine responsible for nearly 9 percent of its output following the disaster. (Reporting by Marta Nogueira, in Belo Horizonte, and Pedro Fonseca, in Rio; writing by Carolina Mandl; editing by Jason Neely and Susan Fenton)