The US Army Corps of Engineers (USACE) on July 24 released the final environmental-impact statement (EIS) for TSX- and NYSE-listed minerals exploration and development company Northern Dynasty Minerals’ Pebble copper/gold/molybdenum project in south-west Alaska.

In its role as lead federal regulator, the USACE’s EIS is more than 2 000 pages, and is the culmination of a 30-month long, intensive review process under the National Environmental Policy Act.

While led by the USACE, the EIS also involved eight federal cooperating agencies, including the US Environmental Protection Agency and US Fish & Wildlife Service; three state cooperating agencies, including the Alaska Department of Natural Resources and the Alaska Department of Environmental Conservation; the Lake & Peninsula Borough and federally recognised tribes.

Following the release of the EIS, technical, permitting and legal experts for Northern Dynasty, and its 100%-owned US-based subsidiary Pebble Limited Partnership, have initiated a comprehensive review of the final EIS.

Northern Dynasty president and CEO Ron Thiessen says although there is more work to be done, the publication of the final EIS is a clear validation that Pebble can be developed in an environmentally sound and socially responsible way, creating benefits and opportunities for the people of Bristol Bay and all Alaskans.

Northern Dynasty believes the final EIS describes a proposed openpit mine and related project infrastructure that will protect water quality, fisheries, wildlife and other valued natural resources.

Further, the miner believes it can secure all necessary federal and state permits in future.

Pebble partnership CEO Tom Collier says the publication of a final EIS is the most significant milestone in the project’s history.

“From the beginning, we dedicated the time, resources and technical work to ensure we had a project that could be done responsibly, be done without harm to the Bristol Bay fishery, and provide meaningful contributions to the communities closest to the project. After an extensive, rigorous, and transparent review process, the USACE has concluded the Pebble project meets that mark.”

Collier adds that he expects the final EIS to contribute to growing support for the Pebble project in local villages and state-wide, and further enrolment in the Pebble performance dividend revenue sharing programme for full-time residents of Bristol Bay.

“Alaskans have demanded that Pebble, and any Alaska resource development project, meet its high standards before the project could advance.”

The final EIS describes a proposed openpit mining operation and associated ore processing facilities in south-west Alaska, an 82-mile road, pipeline and utilities corridor to a permanent, year-round port facility on Cook Inlet.

It also points to a lightering location in Iniskin Bay, a 164-mile natural gas pipeline from existing energy infrastructure on the Kenai Peninsula to the Pebble mine site, a 270 MW natural-gas-fired power plant at the mine site and smaller power generation facility at the port site.

Over 20 years of mining, the Pebble project, as proposed, will extract about 70-million tonnes a year of mineralised material at a low strip ratio of 0.12:1.

A conventional blast-haul-crush and froth flotation milling process, with nameplate capacity of 180 000 t/d, will be employed to produce on average 613 000 t/y of copper/gold concentrate, containing 318-million pounds of copper, 362 000 oz of gold and 1.8-million ounces of silver, as well as 15 000 t/y of molybdenum concentrate, containing 14-million pounds of molybdenum.

Following the release of the final EIS, the USACE is expected to issue a record of decision (RoD) with respect to several of Pebble’s key federal permits.

The Pebble partnership must also secure a number of permits issued by the State of Alaska, a process that is expected to take between two and three years.

Based on the strength of the final EIS and RoD, Northern Dynasty’s goal is to secure a major mining company − or a consortium of companies − to become a partner in the Pebble enterprise and participate in the final stages of project evaluation, design and permitting.