The US Army Corp of Engineers (USACE) has confirmed that an all land-based transport plan to connect the proposed Pebble mine, in Alaska’s Bristol Bay, to a port site is the preferred development scenario for the project.

The USACE selected the land-based transport plan as the 'least environmentally damaging practicable alternative', or LEDPA, for the mine. It includes an 85-mile road north of Lake Iliamna and avoids the need for ferry transport across the lake, project developer Northern Dynasty Minerals explained on Monday.

Northern Dynasty president and CEO Ron Thiessen said that it was not a new plan and that its US-based subsidiary Pebble Limited Partnership (PLP) had studied the option as an alternative in its environmental impact statement (EIS).

The road plan, he said, presented several compelling benefits over the lake ferry options.

“From a cost perspective, the various transportation alternatives evaluated as part of the Pebble EIS over the past several years are similar,” he said. “We had thought the slightly smaller wetlands footprint associated with the lake ferry alternatives might make them preferable to the USACE and other regulatory agencies, but they clearly have judged an all land-based route to be superior from an environmental perspective.

“It’s a decision we welcome and accept. There are clear operational benefits associated with a single mode transportation system versus multi-mode, and we’re confident the northern corridor can be built and operated safely in partnership with local villages and landowners.”

Thiessen said the PLP would work with each of the landowners along the northern corridor, and believed it would secure the authorisations needed to build and operate the transportation system. 

PLP CEO Tom Collier said the USACE contacted Pebble several weeks ago to request that it formally modified its project description to reflect the ‘northern transportation corridor’. He said the driving force behind the USACE’s route change was likely concerns about lake ferry operations expressed by cooperating agencies, including the US Environmental Protection Agency and US Fish and Wildlife Service, as well as members of the public.

Notwithstanding the recent change, Collier said Pebble had studied the ‘northern transportation corridor’ for more than a dozen years, and expects no planning or permitting delays associated with its selection as the LEDPA.

The northern transportation corridor has the added benefit of including a pipeline to transport copper/gold and molybdenum concentrates from the mine site to the port site, thereby reducing truck traffic in the region by about half.

Collier said the announcement of a preferred development alternative for Pebble meant a final permitting decision was one step closer.