Donlin environmental impact statement released

  • After 20 years of exploration and planning, a draft environmental impact statement for the Donlin Gold mine was released Nov. 30. The current estimate for cost to construct the mine is $6.7 billion. Rendering/Courtesy/Donlin Gold

Twenty years in the making, the first draft of an environmental impact statement for the Donlin Gold mine proposed for Western Alaska was released Nov. 30.

“It’s still a long path ahead of us, a lot of challenges ahead of us, but (the EIS) is a significant milestone,” Donlin Gold General Manager Stan Foo told the Resource Development Council of Alaska Dec. 3.

Early resource definition work at the site began in 1995.

A true mega-project, Donlin Gold’s $6.7 billion plan calls 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.

Also supporting the mine operation would be 315-mile, 14-inch diameter natural gas pipeline originating on the west side of Cook Inlet that is needed to fuel the 227 megawatt capacity power plant.

To the south and east, a 30-mile road would connect the mine to a new barge port on the Kuskokwim. Further down the Kuskokwim, port cargo landing facilities would be expanded in Bethel, and new diesel storage tanks would be needed Dutch Harbor.

In all, the direct supply chain in Donlin’s proposal from Cook Inlet to Dutch Harbor would cover approximately 1,050 miles. Donlin Gold is a joint venture between Barrick Gold Corp. and NovaGold Resources Inc.

The natural gas pipeline would initially be only about half full as the average load of the power plant will be about 150 megawatts, according to Foo, leaving potential capacity for natural gas that could be used by local communities to offset high-cost, diesel-sourced heat and power.

Assuming the cost of using Donlin’s pipeline and developing natural gas infrastructure in the region would be the responsibility of a third-party developer, Foo said.

He said the scope of the Donlin project meant compiling a stock of information rarely matched in scale, much like the project proposal. The draft EIS, which is primarily shared in electronic form, would surpass 7,000 printed pages, he surmised.

The mine itself would produce more than 33 million ounces of gold from about 500 million tons of ore over an initial 27-year operating life, or more than 1 million ounces per year. It would process 59,000 tons of ore per day, according to the draft EIS prepared by the U.S. Army Corps of Engineers.

“Very few mines in the world produce more than 1 million ounces of gold each year,” Foo said.

However, gold prices will need to improve between now and the time Donlin decides whether or not it plans to move forward with construction. Foo said the mine would not be feasible at today’s gold prices of less than $1,100 per ounce.

The tailings storage facility, which would be the first full-lined facility in Alaska, he said, would cover approximately 2,300 acres.

During three to four years of construction, the mine would employ about 3,000 workers; once in operation the workforce would average about 800 employees.

Calista Corp., the regional Alaska Native corporation, holds subsurface mineral rights for the mine. The Kuskokwim Corp., the area village corporation, holds surface rights. Both have been “very supportive of the project,” Foo said.

Donlin Gold submitted its EIS application to the Corps in July 2012. A final EIS and subsequent record of decision are expected in mid- to late 2017.

The draft EIS examines five project alternatives beyond Donlin Gold’s preferred alternative and the requisite no-action alternative. Of those, three would change the project in an effort to reduce barge traffic — specifically diesel barges — on the Kuskokwim River, which area residents rely heavily on for travel and subsistence salmon harvests.

The reduced barging options include using liquefied natural gas-powered equipment at the mine, thus reducing the need for diesel fuel; constructing an 18-inch diesel pipeline from Cook Inlet to the mine, which would replace the natural gas line; and moving the port site from Jungjuk Creek 69 miles downstream to Birch Tree Crossing to reduce the distance freight and diesel would travel on the Kuskokwim.

An alternative that would use a dry stack method of tailings storage instead of the tailings pond and dam proposed by Donlin would avoid the risk of a tailings dam failure.

The tailings under this option would be dewatered in a filter plant and saturated into a compactable cake material, according to the draft EIS. That material would then be spread into thin layers with bulldozers in a dry stack tailings area.

The last alternative would shift the natural gas pipeline route slightly through the South Fork Kuskokwim valley. Comments on the draft EIS can be submitted to the Corps through April 30.

Updated: 
12/09/2015 - 4:27pm

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