More Sunshine in the Ambler District
Last updated 11/20/2019 at 11:44am
Trilogy Metals Inc. Nov. 7 reported copper- and zinc-rich volcanogenic massive sulfide intersections in all six holes drilled at the Sunshine prospect on its Upper Kobuk Mineral Projects (UKMP) in Northwest Alaska.
UKMP is a roughly 353,000-square-acre land package that covers most of the Ambler Mining District. This massive land package covers two world-class deposits – Arctic and Bornite –and numerous other prospects and targets across a roughly 60-mile-long stretch of the Brooks Range.
While the 2019 exploration program at UKMP primarily focused on advancing feasibility level studies at Arctic and continuing to expand and upgrade resources at Bornite, Trilogy and South32 Ltd. earmarked US$2 million for exploring earlier staged targets across the district.
To refine targets for this drilling, the 2019 regional program began with a district-wide VTEM (versatile time domain electromagnetic) and ZTEM (z-axis tipper electromagnetic) geophysical surveys flown over both the Cosmos Hills, which hosts Bornite, and the Ambler Belt, which hosts Arctic.
After compiling the geophysical data, Trilogy and South32 drilled six holes at Sunshine, where historical drilling tapped substantial widths of volcanogenic massive sulfide (VMS) mineralization similar to Arctic, which is about eight miles to the east.
In 1997, Kennecott Mines estimated that Sunshine hosts 20 million metric tons of resource averaging 1.4 percent copper, 2.5 percent zinc, 0.5 percent lead and 28.1 g/t silver.
Results from the 2019 drilling confirm the robust nature of this deposit.
SC19-019, reported by Trilogy in September, cut five metals-rich zones:
• 9.1 meters of 3.02 percent copper, 1.42 percent zinc, 0.27 percent lead, 0.14 g/t gold and 24.65 g/t silver;
• 3.3 meters of 1.68 percent copper, 1.77 percent zinc, 0.47 percent lead, 0.12 g/t gold and 27.57 g/t silver;
• 3.7 meters of 4.74 percent copper, 0.97 percent zinc, 0.13 percent lead, 0.15 g/t gold and 28.96 g/t silver;
• three meters of 0.75 percent copper, 1.4 percent zinc, 0.35 percent lead, 0.08 g/t gold and 21.02 g/t silver; and
• 7.88 meters of 2.23 percent copper, 5.62 percent zinc, 1.1 percent lead, 0.18 g/t gold and 46.95 g/t silver in Zone 4.
The five remaining holes all tapped rich zones of VMS mineralization.
SC19-018 cut four mineralized intercepts:
• 5.2 meters of 2.08 percent copper, 3.13 percent zinc, 0.63 percent lead, 0.15 g/t gold and 41.64 g/t silver;
• 6.3 meters of 1.63 percent copper, 1.45 percent zinc, 0.09 percent lead, 0.07 g/t gold and 13.38 g/t silver;
• 7.2 meters of 0.72 percent copper, 2.18 percent zinc, 0.21 percent lead, 0.03 g/t gold and 6.64 g/t silver; and
• 1.1 meters of 1.53 percent copper, 0.35 percent zinc, 0.01 percent lead, 0.03 g/t gold and 3.67 g/t silver.
SC19-020 also cut four mineralized intervals:
• 3.4 meters of 4.15 percent copper, 3.42 percent zinc, 0.83 percent lead, 0.26 g/t gold and 74.35 g/t silver;
• 1.6 meters of 1.43 percent copper, 1.65 percent zinc, 0.40 percent lead, 0.06 g/t gold and 23.3 g/t silver;
• 4.9 meters of 4.47 percent copper, 3.42 percent zinc, 0.01 percent lead, and 0.12 g/t silver; and
• 2.7 meters with a copper equivalent grade of 3.87 percent (3.70 percent copper, 0.44 percent zinc and 0.40 g/t silver.
SC19-021 cut one mineralized interval:
9.7 meters of 3.93 percent copper, 3 percent zinc, 0.77 percent lead, 0.22 g/t gold and 73.1 g/t silver.
SC19-022 cut three mineralized intervals:
• 1.4 meters of 2.89 percent copper, 4.87 percent zinc, 1.41 percent lead, 0.17 g/t gold and 68.3 g/t silver;
• 4.2 meters of 0.34 percent copper, 2.28 percent zinc, 1.07 percent lead, 0.07 g/t gold and 30.63 g/t silver; and
• 15.3 meters of 1.35 percent copper, 2.91 percent zinc, 0.78 percent lead, 0.16 g/t gold and 32.58 g/t silver.
SC19-023 intersected one mineralized interval of:
Five meters of 0.87 percent copper, 1.92 percent zinc, 0.66 percent lead, 0.10 g/t gold and 24.69 g/t silver.
"The grades and widths of mineralization found at the Sunshine prospect are very similar to what we see at the Arctic project and I expect that with more drilling that we can delineate more mineralization at Sunshine," said James Gowans, interim president and CEO, Trilogy Metals. "I also note that the Sunshine prospect is just one of dozens of prospects found within the 70-mile (100 kilometer) long Ambler VMS Belt which has the potential to be one of the most prolific mining districts in the world."
Arctic, the most advanced of the UKMP projects, hosts 43.04 million metric tons of probable reserves averaging 2.32 percent copper, 3.24 percent zinc, 0.57 percent lead, 0.49 grams per metric ton gold and 36 g/t silver.
A 2018 prefeasibility study detailed plans for an open-pit mine to extract the copper- and zinc-rich ore at Arctic and a 10,000-metric-ton-per-day mill that is expected to produce more than 159 million pounds of copper, 199 million lb of zinc, 33 million lb of lead, 30,600 ounces of gold and 3.3 million oz of silver annually over a 12-year mine-life.
A feasibility study for Arctic is slated for completion early next year and the start of permitting for this rich VMS deposit is expected to begin shortly thereafter.
One of the keys to developing a mine at Arctic, and the reason why this world-class deposit has not yet been developed, is the establishment of road access to deliver metals concentrates to world markets.
A 211-mile road that links the Ambler Mining District to Alaska's contiguous road and rail system is currently in the final stages of permitting.
U.S. Bureau of Land Management recently completed the public comment period for a draft environmental impact statement for the proposed Ambler Mining District Industrial Access Project, more commonly known as the Ambler Road.
BLM is currently considering public input as it completes a final EIS for the Ambler Road.
In the meantime, companies such as Trilogy Metals, South32 and Valhalla Metals Inc. continue to add to the billions of pounds of copper, zinc, lead and cobalt; and millions of ounces of silver and gold identified so far in the Ambler Mining District.