A Brazilian federal court on Thursday ordered the suspension of activities at Vale SA's Port of Tubarão because of pollution concerns, halting the world's largest iron ore exporter's ability to ship more than a third of its output. The ruling by the court in Vitoria was made as part of a police investigation at the giant man-made port as Vale comes under increasing pressure over its environmental record in Brazil after a dam burst at a mine run by its Samarco joint venture in October, killing at least 17 people.