The US federal government made a rare intervention to block a gold and copper mine in Alaska on Friday, saying it was compelled to protect the world’s biggest salmon fishery.
The move - a victory for a three-year campaign by salmon fishermen, native tribes and environmental groups - did not amount to an immediate veto on the Bristol Bay mining project.
But Environmental Protection Agency officials made it clear in a phone call with reporters the project to build the largest open pit mine ever constructed in North America was all but over before it even reached the permitting phase.
“There is reason to believe that mining of this deposit would result in significant and irreversible adverse impacts to what is essentially an extremely valuable and unique place”, said Gina McCarthy, the EPA administrator.
“It is not something the agency does very often but the Bristol Bay fishery is an extraordinary resource and worthy of out of the ordinary agency actions to protect it”, she said.
The decision, hailed as an important victory for environmental campaigners, will inevitably be see as a sign of government overreach by supporters of the project.
The EPA has spent three years studying the potential impacts of mining for copper and gold in the Bristol Bay area.
The region is the spawning ground for half of the world’s sockeye salmon.
The EPA’s scientific review last month found that the mine - because of its sheer size and the low-grade of ores - would require a big footprint and generate significant waste.
The operations could destroy up to 151 kilomotres of salmon-supporting streams and between 1,300 to 5,350 acres of wetlands and lakes, the study found.
EPA officials said repeatedly their decision to intervene on the project, through a little used provision of the Clean Water Act, was not an outright death sentence.
But unless Northern Dynasty Minerals Ltd is able to demonstrate it can construct the mine without damaging the fisheries or disrupting the way of life for native tribes, the project would find it exceedingly difficult to go ahead.
“We didn’t come to this decision point to initiate the process lightly”, McCarthy said.
The project will now undergo further review by the EPA. But the project will not be able to obtain the permits needed to dump mining waste into the surrounding Bristol Bay watershed.
The mine, which had investment from Rio Tinto, was cast as one of the biggest environmental decisions awaiting Barack Obama in his second term.
Lisa Murkowski, the Republican Senator from Alaska, and state government officials had warned they would see EPA efforts to block the mine as “federal overreach".
Campaign groups welcomed the news.
“It is difficult to overstate the significance of this announcement”, Trout Unlimited president, Chris Wood, said in a statement. “If the EPA follows the science and follows through on this, it will rank as one of the most significant conservation achievements of the past 50 years".