The U.S. Army Corps of Engineers (USACE) has ordered Northern Dynasty Minerals (TSX: NDM) to craft a plan that would mitigate environmental impacts of its proposed Pebble copper-gold-molybdenum mine in Alaska.
In a letter dated August 20 to the project's developer, Pebble Limited Partnership, USACE said that "mitigation is required for unavoidable adverse impacts to aquatic resources" the project could bring.
The document marks a surprise reversal from the U.S. Army Corps' July decision. The regulator cleared at the time the last environmental hurdle for the proposed Pebble mine.
The Pebble Partnership, in turn, noted that the USACE's fresh request did not constitute a "delay or pause" in the permitting process, adding it would submit a plan "within weeks."
Shares of Northern Dynasty plunged 47% today after media reports said the Trump administration plans to block the Pebble mine, despite denials by the company over the weekend.
Shares were down 40% at 4 p.m. EST, after falling as much as 56% at the open.
The approval of the final environmental impact statement (EIS) for the project was supposed to put an end to an almost two-decade-long permitting process.
The mine only needed the federal nod to go ahead.
Doubts around what many considered a done deal, however, surged in early August, with U.S. President Donald Trump pledging to hear out "both sides of the issue."
The unexpected statement followed a tweet written by Trump's son Donald Jr., which stated he opposed the project supported by his father's administration.
The U.S. Army Corps of Engineers order issued on Aug. 24 comes on the heels of a report by Politico over the weekend, stating that the Trump administration intended to block the controversial project.
The Vancouver-based miner denied the report, saying that the message pushed by the media outlet was "clearly" an error.
"It was likely made by a rush to publish rather than doing the necessary diligence to track down the full story," the company said.
The Pebble mine would be built in the salmon-rich Bristol Bay region, 200 miles southwest of Anchorage. The project has triggered opposition from conservationists and local Indigenous communities, who claim the mine would cause irreparable damage to the environment and the fishery-based economy.
Northern Dynasty said in early August that it supported calls for an independent review of the project's EIS to be undertaken by relevant inspectors general of the U.S. Army, the U.S. Defense Department and the USACE.
The measure, which sought to disprove critics of the development, was followed on Monday by an advertising and outreach campaign to push for the approval of Pebble.
Northern Dynasty said the move targeted "the Trump Administration, the Republican Party, its delegates and influencers."