BRASILIA - Brazil will reinstate a mining ban in a vast area of the Amazon rain-forest, a person with knowledge of the matter told Reuters on Monday, in a victory for environmentalists who feared deforestation.President Michel Temer's administration has decided to revoke an August decree abolishing the National Reserve of Copper and Associates (Renca), an area of roughly 17,800 square miles (46,100 square kilometers) or slightly larger than Denmark, the government source said.The decision will be announced in the Official Gazette on Tuesday, the person said, requesting anonymity as the decision was not public yet.The reserve in the northern states of Amapá and Pará was established in 1984 to protect what are thought to be significant deposits of gold, copper, iron ore and other minerals from the perceived threat of foreign miners at the time.The reserve covers a section of the Amazon, the world's largest rainforest, the preservation of which is seen as essential to soaking up carbon emissions responsible for global warming.The government had argued that lifting the ban would be a boon to the economy and would allow better oversight of the area estimated to have 1,000 people illegally mining there.Mining and Energy Minister Fernando Coelho Filho and other officials have maintained that the reserve merely applied to mining and that other protections for conservation areas and indigenous land inside Renca would remain.But environmentalists argued that merely building roads or infrastructure in the area would bring deforestation and threaten biodiversity, with Brazilian supermodel Gisele Bundchen tweeting against the decree."If carried out, the cancellation of the decree shows that, no matter how bad, there is no leader absolutely immune to public pressures," Marcio Astrini, coordinator of public policy for environmental group Greenpeace, said in a statement."It is a victory of society over those who want to destroy and sell our forest."The government has repeatedly backtracked in the face of the criticism, legal action and an effort to overturn the decree in Congress.Temer's administration first reissued the decree with more details on other remaining protections inside the area. Later the Mining and Energy Ministry said it would put any action related to it on hold for 120 days to allow for public discussion.A judge also granted an injunction blocking the decree.The official repeal by Temer expected on Tuesday will end the controversy.