Trilogy announces successful drilling at third Ambler prospect
The company with two copper prospects in a remote, mineral-rich region of Alaska is adding another.
Trilogy Metals Inc. announced on Nov. 7 that it hit copper, zinc, silver and small amounts of gold and lead during summer drilling at its Sunshine prospect in the Ambler mining district northwest of Fairbanks.
The Vancouver-based junior mining firm hit zones of at least 0.87 percent copper in each of the six boreholes tested; all but one of the holes contained copper zones with mineralization excess of 2.08 percent, according to the exploration report.
For comparison, a 2016 research article published in the scientific journal Resources concluded that the average ore grade at currently producing copper mines worldwide is approximately 0.62 percent. However, the high costs associated with developing isolated prospects in Alaska often require much better-than-average resources to justify turning a prospect in the state into a producing mine.
Zinc occurrences in the same zones were largely in excess of 2 percent, with silver densities reaching 74 grams per metric ton of ore.
The results are from 1,356 meters of drilling over the six boreholes. Trilogy targeted the specific drilling sites following a $2 million electromagnetic geophysical survey the company conducted last spring over much of the Ambler prospect belt.
Interim Trilogy CEO James Gowans said in a formal statement that Sunshine is just one in a host of prospects across the large Ambler mining region, “which has the potential to be one of the most prolific mining districts in the world.”
“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 we can delineate more mineralization at Sunshine,” Gowans said.
Other companies are exploring other prospects in the Ambler region, which stretches for roughly 75 miles along the southern flank of the western Brooks Range in the upper reaches of the Kobuk River drainage. Trilogy is also working in other parts of the area, including its aforementioned and advanced Arctic prospect, about eight miles east of Sunshine.
Former CEO Rick Van Nieuwenhuyse said last spring that Trilogy leaders hope to complete a feasibility study of Arctic early next year. Environmental permitting for Arctic should start once the environmental impact statement for the controversial, state-sponsored 211-mile Ambler Mining District Industrial Access Project is closer to complete as well, he said.
The high-grade Arctic prospect covers approximately 36 million metric tons of ore with 3.07 percent copper, 4.23 percent zinc, 0.73 percent lead and 47 grams per ton of silver.
Generally referred to as the Ambler road, the up to $350 million access project is a state-led plan for an unimproved industrial road off of the Dalton Highway to reach the large Ambler mining district.
Under the plan, the Alaska Industrial Development and Export Authority would build the road via revenue bonds once it secures commitments from mining companies that would ultimately fund the project through tolls and use agreements.
The road project has drawn opposition from local Alaska Native organizations, residents of the area and environmental groups who are worried the project will disrupt caribou migrations important for subsistence harvests.
The proposed mines have also drawn scrutiny for potential impacts to salmon and whitefish runs in the Kobuk River drainage.
In addition to the young Sunshine and mature Arctic prospects, Trilogy is also working on the mid-stage, copper-based multi-metal Bornite prospect to the south of the other two. The company completed more than 7,600 meters of drilling this year from 10 boreholes in and around the known resource.
The $9.2 million drilling program at Bornite was funded by Australia-based South 32 through an agreement the companies signed in 2017.
According to a company report issued prior to this year’s drilling, Bornite contains indicated resources of more than 40 million metric tons of ore holding an average of 1.02 percent copper for 913 million pounds of the metal.
Elwood Brehmer can be reached at [email protected].