Name of the Project
Arctic copper/zinc/lead/silver/gold project.

Location
The Ambler mining district of north-western Alaska, in the US.

Project Owner/s
Ambler Metals, a joint venture between Trilogy Metals and South32.

Project Description
A feasibility study has described the technical and economic viability of establishing a conventional openpit copper/zinc/lead/silver/gold mine and mill complex for a 10 000 t/d operation for a minimum 12-year life-of-mine (LoM).

The feasibility study forecasts an average yearly payable production to be more than 155-million pounds of copper, 192-million pounds of zinc, 32-million pounds of lead, 32 165 oz of gold and 3.4-million ounces of silver.

Over the operation’s LoM, production is forecast at 1.9-billion pounds of copper, 2.3-billion pounds of zinc, 388-million pounds of lead, 386 000 oz of gold and 40.6-million ounces of silver.

The feasibility study is based on an openpit mining operation, with a conventional milling and flotation process that results in the production of copper, zinc and lead concentrates.

Based on the feasibility level metallurgical work on the sulphide mineralisation, the average recoveries are projected to be 89.9% for copper, 90.6% for zinc and 79.0% for lead in their respective concentrates. More than 60% of the recovered payable silver and gold report to the lead concentrate at 95% payable. The LoM strip ratio is estimated at 6.9:1.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a pretax net present value, at an 8% discount rate, of $1.6-billion and an internal rate of return of 31% for the base case, with a payback of 2.4 years.

Capital Expenditure
The project will require an initial capital expenditure of $905.6-million.

Planned Start/End Date
Not stated.

Latest Developments
Ambler Metals has reported that it will soon start the formal permitting process for the Arctic project.

An independent consulting company has completed a preparedness review of the draft permitting package for the project and, with some minor changes, the application will be submitted to the US Army Corps of Engineers (USACE) in the first quarter of 2022.

As the project is located on state and private land, the key federal permit will be the 404 Dredge, or Fill, Permit that is issued by the USACE, the lead agency during the federal permitting process.

In parallel with the federal permitting process, the state of Alaska will have to issue several permits and there will also be other permits issued by the Northwest Arctic Borough, with the overall permitting process expected to take 24 to 30 months to be completed.

Trilogy and South32 have also approved a 2022 budget of $28.5-million for Ambler.

The 2022 budget for Ambler will cover up to 10 000 m of helicopter-supported diamond drilling that is expected to start in early June. The meterage will be divided between resource development drilling at Arctic and scout drilling of both volcanogenic massive sulphide targets in the Ambler belt, with a focus on targets near Arctic, and carbonate-hosted copper targets around Bornite and the Cosmos Hills.

Key Contracts, Suppliers and Consultants
Ausenco Engineering Canada Inc (independent consultants – feasibility study); Wood Canada (mine planning); SRK Consulting (tailings and waste design, hydrology and water management studies); BD Resource Consulting and SIM Geological (mineral resource estimates); International Metallurgical & Environmental Inc (metallurgy and recoveries); and Integrated Sustainability Consultants (selenium water treatment plant design).

Contact Details for Project Information
Trilogy Metals, tel +1 604 638 8088 or email info@trilogymetals.com.
South32,tel +61 8 9324 9000.