North of 60 Mining News - The mining newspaper for Alaska and Canada's North

Ambler Metals LLC, a joint venture equally owned by Trilogy Metals Inc. and South32 Ltd., dialed back 2023 exploration at its Upper Kobuk Mineral Projects as it waited for the U.S. Bureau of Land Management to reevaluate previously issued federal permits for a proposed 211-mile industrial access road to the metal-rich Ambler Mining District in Northwest Alaska.

Covering 448,217 acres of the famed Ambler District, UKMP hosts the advanced staged Arctic Mine project and more than a dozen similar volcanogenic massive sulfide targets on state lands, plus the world-class Bornite copper-cobalt deposit and similar carbonate-hosted prospects on land owned by the Northwest Alaska Native regional corporation, NANA Corp.

A 2020 feasibility study for Arctic detailed plans for a financially robust open-pit mine and processing plant that would produce 1.9 billion pounds of copper, 2.3 billion lb of zinc, 388 million lb of lead, 386,000 ounces of gold, and 40.6 million oz of silver over an initial 12-year mine life.

This operation is based on 43 million metric tons of reserves averaging 2.32% copper, 3.24% zinc, 0.57% lead, 0.49 grams per metric ton gold, and 36 g/t silver.

The feasibility of developing a mine at Arctic, however, is predicated on the development of a road that would allow the delivery of metal concentrates to market.

BLM and the National Park Service originally issued the federal authorization for the Ambler Road in 2020. In 2022, however, the federal land manager remanded the permits, citing a lack of adequate consultation with Alaska tribes and an evaluation of potential impacts on subsistence uses as its reasons.

A draft supplemental environmental impact statement that incorporates the citied missing data was released in October, and the final EIS and record of decision on the reevaluated Ambler Access Project is slated for the second quarter of 2024.

The road permitting delay has set back the envisioned timeline for development of Arctic and the rest of the district. As such, Ambler Metals dialed back its 2023 field work.

On the geological front, the JV had a small team continuing work started in 2022 on the geological setting and alteration at Arctic.

Critical Bornite

One of the more exciting programs carried out at UKMP was an evaluation of germanium and other critical minerals at the world-class Bornite copper deposit about 16 miles southwest of Arctic.

According to an early 2023 calculation, Bornite hosts 202.7 million metric tons of inferred resource averaging 1.46% (6.51 billion lb) copper.

The deposit also hosts appreciable quantities of cobalt. A previous calculation estimated that the portion of the deposit that was sampled for this battery metal hosted 88 million lb of cobalt in 184.8 million metric tons of inferred resource averaging 0.021% cobalt.

Metallurgical test work to potentially increase cobalt reporting with copper concentrate was initiated in July.

Bornite may also be a significant source of the germanium essential to both clean energy and high-tech.

"Germanium is an important metal with numerous applications, particularly in the manufacture of semiconductor chips, fiber-optic systems, and high efficiency solar cells," said Trilogy Metals President and CEO Tony Giardini.

During the summer 2023 field program, Colorado School of Mines led a study supported by the U.S. Geological Survey to understand the germanium potential at Bornite.

The USGS first recognized germanium mineralization at Bornite in the 1980s, and Trilogy has suspected that the values of this tech metal have been underrepresented since 2011.

As part of a Master of Science thesis, Alexander Jones sampled core from five historical Bornite drill holes for germanium. These samples, which were selected from core with high copper grades contained as much as 125 parts per million germanium.

Though these samples represent only a small part of the South Reef area of the Bornite deposit, Trilogy says the results clearly demonstrate that germanium is present at levels that are significantly higher than previously reported.

More importantly for potential future germanium byproduct recoveries at Bornite, the thesis work confirms a close association between the germanium sulfide mineral renierite and the copper minerals in the deposit, which suggests the germanium will at least partially be recovered in the copper concentrate during flotation without special or additional processing.

In addition to Ambler Metals' program, the Bornite Camp supported crews completing environment baseline, cultural resource, and other studies in support of BLM's Ambler Access Project SEIS and more robust future field work in the Ambler District if the federal land manager reapproves the road project by mid-2024.

Helpmejack discoveries

Independent of work carried out by the JV, Trilogy carried out stream sediment and rock sampling that identified two zinc-enriched VMS targets at Helpmejack, a project about 110 miles southeast of Arctic.

In 2022, Trilogy staked 19,520 acres of state claims over the Helpmejack area, plus 12,480 acres of claims over Malemute, a prospective area about 35 miles further east.

"We see upside in the Helpmejack and Malamute claims, which have relatively low holding costs but offer potential to add value for shareholders, in addition to the primary UKMP asset, especially as the United States is looking to secure domestic supplies of critical metals," said Giardini.

During the 2023 program, Trilogy traced anomalous levels of zinc identified in stream sediment samples to several upstream tributaries with significant levels of zinc (greater than 500 parts per million) and cadmium (greater than 10 ppm), with anomalous levels of other elements characteristic of Besshi-style VMS deposits and shale-hosted zinc deposits.

These drainages follow the strike of the geology for more than three miles through the center of the claim block. Bright orange iron oxide staining along several of these streams is visible from the air, and a grab sample collected adjacent to mapped mafic volcanics assayed 0.8% zinc with anomalous cadmium, manganese, cobalt, molybdenum, nickel, sulfur, and antimony.

A stream-sediment sample collected south of this trend contained 3,100 ppm zinc and 49 ppm cadmium. Two repeat samples collected nearby contained 3,120 ppm zinc and 39 ppm cadmium, and 3,690 ppm zinc and 63 ppm cadmium.

Shane Lasley for Data Mine North

A sample with copper, cobalt, and likely germanium collected from a pile of mineralization excavated from a shaft Kennecott Exploration sunk into Bornite deposit during the 1960s.

Stream-sediment sampling on the Malamute claims verified anomalous levels of cobalt identified during historical state sampling. Trilogy's samples contain greater than 300 ppm cobalt and up to 240 ppm copper in four adjacent north-south drainages, and define a 1.5- by 3.7-mile target area that is largely covered by overburden.

Trilogy says additional mapping and sampling on both eastern Ambler schist belt properties is warranted.

South32 is also exploring high-quality projects covering Arctic-like deposits in the eastern Ambler schist belt area. The Australian-based company's land holdings in this area include Roosevelt, an enormous block of claims that covers a roughly 50-mile-long stretch of the Ambler schist belt just north of the proposed Ambler Road and about 15 miles east of Helpmejack.

Author Bio

Shane Lasley, Publisher

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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