The Pebble copper and gold project has a new preliminary economic assessment (PEA), providing fresh cost and price estimates and detailing an infrastructure plan that uses the “southern route” for the project access.

The project, being developed by Vancouver-based Northern Dynasty, has been surrounded by controversy and has been stuck in limbo since an Environmental Protection Agency (EPA) decision to block the mine.

Northern Dynasty says the 2023 PEA updates the EPA final determination and the US Army Corps of Engineers record of decision appeal processes.

The 2023 PEA provides production, financial and cost estimates for a proposed 20-year, 180 000 t/d openpit operation with conventional processing producing two concentrates for the Pebble project.

The Pebble project would be capable of processing 1.3-billion tons of mineralised material over 20 years of mining at a strip ratio of 0.12:1, with an average yearly mine operating cost of $14.17/t.

On average, the mine will produce 320-million pounds a year of copper; 368 000 oz/y of gold; 15-million pounds a year of molybdenum; 1.8-million ounces a year of silver and 10 000 kg/y rhenium.

Over its life-of-mine, Pebble will unearth 6.4-billion pounds of copper; 7.4-million ounces of gold; 300-million pounds of molybdenum; 37-million ounces of silver; and 200 000 kg rhenium.

The total initial capital cost for the design, construction, installation and commissioning of the proposed project is estimated to be $6.77-billion.

"The proposed mine for the Pebble project would provide good-paying, year-round employment for thousands of Alaskans, something desperately needed in Southwest Alaska," said Northern Dynasty president and CEO Ron Thiessen.

“The mine would mean substantial tax revenues for Alaska, including contributions to the Alaska Permanent Fund, which will be important for the future economic sustainability of the region. New infrastructure developed to support the proposed project would offer the additional benefit of potentially lowering energy costs for the region. The July 2020 environmental-impact statement of the Pebble project states that the proposed mine can be developed and operated without harming the fishery, and so, with Alaska's excellent track record of managing all its resources for the benefit of its people, it can have both the mine and the fishery."