The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
North of 60 Mining News - January 15, 2025
A high-grade copper-cobalt sample from the Bornite deposit in Alaska's Ambler Mining District.
UKMP and surrounding areas of interest cover more than a 60-mile-long stretch of the Ambler District.
The proposed Ambler Road would connect the Ambler Mining District to Alaska's highway system.
A new preliminary economic assessment (PEA) for developing an underground mine at the high-grade Bornite copper deposit in the Ambler Mining District shows that the two largest deposits outlined so far at the Upper Kobuk Mineral Projects (UKMP) could deliver copper and other metals critical to the United States into the nation's supply chains for more than three decades.
UKMP is an enormous package of state and Alaska Native lands owned by NANA Corp. that covers more than 448,000 acres of mineral-rich real estate in Northwest Alaska.
The roughly 45-mile-long state land package at UKMP hosts the Arctic copper-zinc-gold-silver mine project and more than a dozen similar volcanogenic massive sulfide prospects identified along a VMS belt that extends beyond UKMP boundaries. The adjacent NANA-owned UKMP lands host Bornite and similar carbonate-hosted copper deposits.
Though Bornite hosts more than 6.5 billion pounds of copper, along with appreciable quantities of cobalt and germanium, this world-class deposit has been simmering on the back burner as Ambler Metals – a 50-50 joint venture formed between Trilogy and South32 Ltd. to advance UKMP – focused its efforts on advancing the nearby Arctic Mine project into permitting and development.
According to a feasibility study updated for Ambler Metals in 2023, a financially robust open-pit mine at Arctic would produce 1.93 billion lb of copper, 2.24 billion lb of zinc, 334.8 million lb of lead, 423,000 oz of gold, and 36 million oz of silver over 13 years of operation.
The PEA prepared for Trilogy shows that an underground mine at Bornite could continue delivering copper critical to the energy transition for another 17 years.
"Although we believe that further exploration along the 100-kilometer volcanogenic massive sulfide belt will extend the mine life of the Arctic project beyond the 13 years established by the current Arctic Feasibility Study, the Bornite PEA study shows it is possible, with existing known resources, to continue mine activity at the UKMP beyond 30 years," said Trilogy Metals President and CEO Tony Giardini.
UKMP and surrounding areas of interest cover more than a 60-mile-long stretch of the Ambler District.
Bornite has long been considered a world-class deposit that would support the continuation of mining operations in the Ambler District as the Arctic mine about 16 miles (25 kilometers) to the north wound down. The new Bornite PEA provides some insights into the economic and engineering parameters of that mine.
Utilizing the infrastructure established for a mine at Arctic, the PEA outlines an underground mine at Bornite that would produce roughly 1.9 billion pounds of copper over 17 years of operation.
At an estimated mining rate of 6,000 metric tons per day, the PEA envisions operating the Arctic mill modified for Bornite ore for two weeks and then shutting down for a week for mining to catch up.
While the mining rate is only about 60% of milling capacity, the Bornite deposit has the potential to support a larger operation. The underground mine designed for the PEA would target 36.9 million metric tons of high-grade ore averaging 2.61% (2.13 billion lb) copper.
The overall Bornite deposit hosts 208.9 million metric tons averaging 1.42% (6.53 billion lb) copper, indicating the potential for an increase in the mining rate, as well as the life of the mine.
Based on a long-term copper price of $4.20/lb, the smaller but higher-grade Bornite mine outlined in the PEA would generate a post-tax net present value (NPV) (8% discount) of $394 million and a post-tax internal rate of return (IRR) of 20%. This operation is expected to pay back the estimated $503.8 million of initial capital expenditures in 4.4 years.
The Bornite mine economics included in the PEA do not consider any of the cost synergies related to the transitioning directly from mining at Arctic to Bornite. These synergies include $428 million of closure and reclamation costs included in the Arctic Mine feasibility study. Much of the Arctic closure costs would not be required with the sequential start of Bornite, which would be utilizing the mill and storing tailings at the Arctic mine site.
In addition to economic benefits, this plan to process ore and store tailings at Arctic would have environmental advantages. The tailings from the carbonate-based Bornite ore would help neutralize the high-sulfide tailings produced from Arctic VMS ore.
The proposed Ambler Road would connect the Ambler Mining District to Alaska's highway system.
The establishment of a 211-mile road would allow Arctic and Bornite to deliver concentrates enriched with critical minerals and precious metals to market, which is essential to the economics of both proposed mines.
Following the U.S. Bureau of Land Management's (BLM) 2020 issuance of federal permits to build the Ambler Road, Ambler Metals was preparing to file applications for the permits to build a mine at Arctic.
After President Biden took office, however, BLM pulled the permits for additional review and then issued a new decision not to authorize the building of the Ambler Road. With the road permits pulled and then reversed, Ambler Metals did not initiate the federal permitting process for Arctic.
With President-elect Donald Trump's imminent return to the White House, there is renewed hope that the Ambler Road permits will be re-established.
Just two days after being reelected, Trump posted a video vowing to "maximize Alaska's mining potential."
In a 28-page "Alaska Priorities for Federal Transition" report sent to Trump's transition team in December, Alaska Gov. Mike Dunleavy informed the incoming president that restoring the Ambler Road permits is one of the ways his administration can help Alaska realize value from its rich mineral endowment.
"The Ambler Mining District has extensive deposits of critical minerals and could be a secure, reliable U.S. supply-chain resource, essential for our Nation's tech-focused economy, green energy products, and military effectiveness," the Dunleavy administration penned in the Alaska priorities plan.
The Bornite Mine PEA completed for Trilogy demonstrates that the world-class deposits already outlined at the west end of the proposed Ambler Road could feed copper and other metals essential to America's tech-focused economy into the nation's supply chains for more than 30 years.
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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