The long-awaited environmental impact statement for the Donlin Gold mine in Western Alaska will be published on April 27 by the U.S. Army Corps of Engineers, Alaska District officials said.

The Corps of Engineers has been working on the EIS since December of 2012 while company Donlin, a joint venture between Barrick Gold Corp. and NovaGold Resources Inc., has been working on the mine itself for 22 years, said Donlin spokesman Kurt Parkan.

“It's a good day. We're happy that we've reached (the final EIS). That's a big milestone,” Parkan told the Anchorage Daily News.

Unlike a draft EIS — Donlin's draft was published in November 2015 — a final EIS includes the oversight agency's recommendations on how a project can be adjusted to minimize its environmental impacts. A "no action alternative," or a recommendation to not approve the project, can also be selected.

Donlin Gold estimates the mine and associated infrastructure that includes a natural gas pipeline from west Cook Inlet and fuel storage all the way in Dutch Harbor, will cost $6.7 billion based on its plan from a 2011 feasibility study.

Parkan said the next steps will be getting a record of decision from the Corps later this year as well as securing numerous other permits, among them approvals for water discharge, waste management and a tailings dam safety permit that will require geotechnical drilling this year.

After the permits are secured company leaders will reevaluate the project's economics, which they acknowledge are subject to the volatility of gold prices, and begin the search for financing if the project pencils out.

A true mega-project, Donlin Gold's is for a conventional open-pit mine 1.5 miles across and up to 1,200 feet deep about 10 miles north of the village of Crooked Creek in the Upper Kuskokwim River drainage. A tailings facility, large power plant, workers' camp and 5,000-foot airstrip would accompany the mine.

As planned the mine would produce about 1.1 million ounces of gold per year over a 27-year mine life for a total of about 33 million ounces of the precious metal, making it one of the largest open-pit gold mines on Earth.

The mine site, on lands owned by The Kuskokwim Corp. and Calista Corp., the area village and regional Native corporations, respectively, would also include a fully lined, 2,300-acre tailings facility to store the processed ore.

A 30-mile road would connect the mine to a new barge port on the Kuskokwim. Further down the Kuskokwim, port cargo facilities would be expanded in Bethel, and new diesel storage tanks would be needed Dutch Harbor to supply fuel for equipment at the mine.

In all, the direct supply chain in Donlin's proposal from Cook Inlet to Dutch Harbor would cover approximately 1,050 miles.