The leases were cancelled by former president Barack Obama's administration in 2016, but that decision was later reversed by the Trump administration. Biden administration officials said the Trump administration erred in giving the leases back. "We found the leases were improperly renewed in violation of applicable statutes and regulations, and we are taking action to cancel them," said US Interior Secretary Deb Haaland, reported Reuters.
The company said the leases have been held for more than 50 years and that the decision, "is disappointing, but not surprising given the series of actions the administration has taken to try and shut the door on copper-nickel mining in northeast Minnesota," it said.
"This is not about law; this is a political action intended to stop the Twin Metals project without conducting the environmental review prescribed in law," the company said, indicating it plans to challenge the decision.
The Biden administration previously announced a plan in 2021 to impose a 20-year ban on mining in Minnesota's Boundary Waters region, close to where the Twin Metals project is located.
Antofagasta Minerals submitted a mine plan of operations to the US Bureau of Land Management and Minnesota Department of Natural Resources in 2019.
Twin Metals has invested some US$450 million to date on the project and is contemplating a $1.7 billion investment for a 18,000 tonnes per day underground mining operation with a 25-year mine life. The mine will produce copper, nickel, cobalt and platinum group metals (PGM) as well as some gold and silver. Northeast Minnesota, where Twin Metals is located, hosts 95% of the known nickel reserves in the US, 88% of the cobalt, 75% of PGMs and 34% of copper.
Antofagasta Minerals seeks to deploy the most up-to-date environmental management practices at Twin Metals including the use of dry stack tailings and back-filling up to half of its tailings underground. The company says the mine will have minimal surface impact at about only 15% of what a traditional openpit operation would be, while also reducing sound and air impacts. The geology of the deposit means mining will not be acid generating.
"The Twin Metals project is aligned with many of the top priorities of the Biden Administration, including production of domestic critical minerals needed for US national security and the green energy economy," Julie Padilla, chief regulatory officer at Twin Metals Minnesota, told Mining Journal in 2021.