Perpetua eyes possible Stibnite mine expansion – Valley Lookout
A gold and antimony mine approved in eastern Valley County is well-positioned for future expansion, according to executives for the mining company.
On Wednesday, Perpetua Resources outlined preliminary plans for a possible expansion of its Stibnite mine, which was approved earlier this year following an eight-year review by the Payette National Forest.
Marcelo Kim, who chairs the company’s corporate board, told shareholders that the company will explore additional zones that could add as much as 2.4 million ounces of gold to the mine’s current reserve of 4.8 million ounces.
“We believe there are ample high-grade extensions to our existing reserves that we plan to drill out,” Kim said. “Should we be able to bring this material into reserves, we could see a substantial benefit to our gold production from higher grades as well as antimony production.”
A shareholder presentation included a map showing more than two dozen new exploration zones and nine “priority targets.” Many of the areas are adjacent to the two existing pit mines the company is already permitted to develop.
Kim said the exploration zones are based on mineralization the company has observed and “not blue sky prospects.”
However, any expansion of the company’s planned mining operations would require further regulatory approval from the Payette and other agencies.
Marty Boughton, a Perpetua spokesperson, told Valley Lookout the acreage for the exploration zones is not currently available.
“We haven’t finalized a detailed plan yet, just some forward-looking targets,” Boughton said. “Our primary focus is bringing the Stibnite Gold Project as permitted online.”
Latest stock offering
Wednesday’s investor presentation came on the heels of Perpetua securing another $425 million in financing following a stock offering that opened last week.
The offering initially was for $300 million, but the company increased it to $325 million to fund the additional exploration work, Kim said.
At the same time, Paulson & Co., a New York City investment firm led by billionaire John Paulson, agreed to purchase another $100 million in stock.
The purchase raised Paulson’s total investment in Perpetua to $185 million since 2016. The firm owns about 32.3 million shares of Perpetua stock, giving it a 31% ownership stake in the company as its largest investor, Boughton said.
Kim, a Paulson partner since 2011, was appointed to his role as board chairman in 2020 when five longtime board members resigned amid Paulson’s demands for leadership changes.
$2B loan application
Most of the $425 million Perpetua raised through the stock offering will be used to meet equity requirements for a $2 billion loan the company applied for through the Export-Import Bank of the United States.
If approved, the loan would fund the $2.2 billion cost to build the mine, a process that Perpetua estimates would take two to three years.
Construction cannot begin, however, until Perpetua receives approval from the Payette on a financial assurance package that guarantees funding for clean-up of the site.
The company is actively seeking financial assurances totaling about $155 million to cover the construction phase of the project. It currently expects to begin mining operations in 2029.
Project background
Perpetua plans to extract more than $6 billion in gold, silver, and antimony from Stibnite, the site of historic mining operations during World War II and as far back as 1899.
The mine could produce an estimated 148 million pounds of antimony and 4.8 million ounces of gold, which would account for nearly all of the mine’s projected revenue.
The metals would be extracted from three open pit mines totaling about 473 acres within the 1,740-acre project zone, which is about three miles from the Frank Church – River of No Return Wilderness.
Opponents of the mine fear it could pollute the East Fork South Fork Salmon River, which flows through the project site, and cause other environmental damage.
Water quality in the East Fork and other streams at the proposed mine site does not currently meet federal drinking water standards due to high concentrations of arsenic and antimony from pollutants left by previous mining companies.
Perpetua’s mining proposal is authorized by the General Mining Act of 1872, a federal law that allows anyone to patent mining claims on public land.
A review of the project began in 2016 under the National Environmental Policy Act, a federal law that requires all projects that could affect natural resources to be studied for environmental harm. 
Fire crews remain on the ground in the Payette National Forest, working to contain three wildfires, with efforts focused on protecting structures at two lodges along the Salmon River, according to the U.S. Forest Service.
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