The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Third best intercept at world-class VMS deposit in NW Alaska North of 60 Mining News – December 3, 2021
Despite the unusually wet weather in the Ambler District this summer, crews completed 4,131 meters of drilling in 18 holes this year at the Arctic deposit.
Massive to semi-massive chalcopyrite (copper mineral) from the 19.9-meter intercept averaging 11.76% copper encountered in hole AR21-0176 at Arctic.
Trilogy Metals Inc. Nov. 29 reported that one infill hole drilled this year at Arctic is the third-best intercept ever encountered at this high-grade volcanogenic massive sulfide deposit at the Upper Kobuk Mineral Projects in Northwest Alaska.
"The 2021 drilling campaign confirms that the Arctic project has some of the highest grades of polymetallic mineralization in the world with copper-equivalent grades frequently in the double digits," said Trilogy Metals President and CEO Tony Giardini.
A 2020 feasibility study details plans for a financially robust mining operation at this world-class deposit 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.
While high-grade VMS deposits such as Arctic are typically mined from underground, the Arctic feasibility study details plans for a lower cost open-pit mine feeding a 10,000-metric-ton-per day mill.
Ambler Metals LLC, a joint venture operating company equally owned by Trilogy and South32 Ltd., completed an 18-hole (4,131 meters) diamond drill program this year designed to upgrade a portion of the indicated resources at Arctic to the higher confidence measured category, as well as provide material for metallurgical testing and geotechnical information.
The joint venture company has now received assay results from the first two resource upgrade infill holes.
The best of these holes, AR21-0176, cut three mineralized intervals:
• 19.91 meters averaging 6.75% copper, 7.59% zinc, 1.68% lead, 1.26 g/t gold, and 97.13 g/t silver from a depth of 128 meters.
• 6.76 meters averaging 1.55% copper, 6.61% zinc, 1.58% lead, 0.12 g/t gold, and 20.68 g/t silver from 164.7 meters.
• 0.83 meters averaging 1.9% copper, 1.76% zinc, 0.3% lead, 0.22 g/t gold, and 24.9 g/t silver from 176.1 meters.
When you include the value of all the metals, the 19.91-meter intercept in AR21-0176 comes to 11.76% copper-equivalent.
"Grades of almost 12% copper equivalent over 20 meters, considered close to true width, is one of the best intervals at Arctic since the first hole was drilled in 1967," said Trilogy Metals Vice President of Exploration Richard Gross.
AR21-0174, also an infill hole, cut 10.12 meters of 3.21% copper, 6.14% zinc, 1.46% lead, 0.69 g/t gold and 49.74 g/t silver for a copper equivalent grade of 6.84%.
These infill drill results follow assays reported by Trilogy on Nov. 22 from two geotechnical holes drilled to test the stability of the pit wall on the northeast side of the proposed Arctic Mine. Both holes, AR21-0173 and AR21-0175, encountered high-grade mineralization beyond the currently defined pit at Arctic.
Hole AR21-0173 cut 3.77 meters averaging 2.15% copper, 0.87% zinc, 0.34% lead, 0.83 g/t gold, and 82.89 g/t silver from a depth of 110.5 meters at the north edge of the deposit.
Hole AR21-0175 cut three high-grade zones on the northeast edge of the proposed open pit. From a depth of 71.9 meters, this hole cut 24.94 meters averaging 1.85% copper, 2.96% zinc, 0.57% lead, 0.28 g/t gold, and 27.09 g/t silver.
"The copper-equivalent grades at Arctic rival some of the high-grade copper projects in Africa, while being in one of the most stable mining jurisdictions in the world," said Giardini.
Assays are pending for eight infill and six geotechnical holes drilled at Arctic, as well as exploration drilling UKMP.
"We are looking forward to seeing the results of the other 14 drill holes at Arctic as well as from the regional drill program," said Gross.
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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