From the air it looks like just another tract of Alaska’s endless, roadless tundra, pockmarked with lakes and ponds, with a scattering of some of the state’s craggy mountains.
But this swath of land, home to foraging bears and spawning salmon about 200 miles southwest of Anchorage, has been a battleground for years.
The fight is over what lies just below the surface: one of the richest deposits of copper, gold and other valuable metals in the world. It sets two of the state’s most important industries, mining and fishing, against each other.
A mining company plans to dig a pit, more than a mile square and a third of a mile deep, over two decades to obtain the metals, estimated to be worth at least $300 billion.
Supporters say the project, known as the Pebble Mine, would be an economic boost for a remote region that has missed out on the North Slope oil boom and other resource-extraction development in the state over the past half century. It would employ nearly 1,000 people, and the Canada-based company, Northern Dynasty Minerals, would pay for infrastructure improvements in some Alaska Native villages and provide cash dividends totaling at least $3 million to people in the area.
The mine will be located in two watersheds that feed fish-spawning rivers. Opponents say tailings left from the mining operation pose risks if heavy metals or other contaminants from them leach into groundwater or if dams holding back the tailings fail in an earthquake.
Tom Collier, the chief executive of Pebble Partnership, the Northern Dynasty subsidiary developing the project, said the mine was designed to minimize those and other risks.
Under President Barack Obama, the project was blocked in 2014 by the Environmental Protection Agency, largely over concerns about the risks to salmon.
But the Pebble Mine gained new momentum under President Trump’s more industry-friendly policies. While at first continuing its criticism of the project, the Environmental Protection Agency eventually reversed the Obama-era decision blocking it.
In addition to the open-pit mine, the plan would include large dammed ponds for the tailings, some of them toxic, that result from mining and concentrating the metals, 80 miles of road and pipeline to carry the concentrate to a new port on Cook Inlet, and a 165-mile natural gas pipeline for a generating plant to power the operation.
In an interview this week, Mr. Collier described the release of the final impact statement as “the most significant day in the 15-odd-year history of the Pebble project.”
“It’s really for the first time that a federal agency has conducted a rigorous scientific review of the specific project Pebble wants to build,” he said. The conclusion that the mine was not going to damage the salmon fishery would be “unequivocal,” he added.
But in public comments on a draft of the environmental impact statement last year, opponents suggested that the review was not so rigorous. They pointed to numerous hazardous risks, including the potential for a tailings dam failure that could contaminate waterways used by spawning fish and harm the Bristol Bay fishery, which employs about 15,000 people.
Alaska is the most seismically active state in the nation, and critics said the Corps of Engineers had not taken sufficient account of the risk of earthquakes or volcanic activity, and that its analysis of the dam designs was inadequate. Some of the dams would be hundreds of feet high.
Tailing dam failures can unleash a sudden flood of contaminated slurry with disastrous effects. A 2019 failure at an iron mine in Brazil, for example, killed more than 250 people. Given the Pebble Mine’s remote location, the risk to people might be low, but the heavy metals and other contaminants could make nearby rivers toxic to fish.
This year, after the Corps sent a preliminary version of the final impact statement to federal and state agencies and other groups, the critiques continued, according to documents obtained by opponents of the project. U.S. Fish and Wildlife Service scientists, for example, wrote that the version failed to acknowledge that habitat destruction from development of the mine “would erode the portfolio of habitat diversity and associated life history diversity that stabilize annual salmon returns to the Bristol Bay region.”
At a news briefing this week, David Hobbie, chief of the Corps’ Alaska district regulatory division, said, “We’ve done our best to address all the comments we’ve received.”
In a month or perhaps longer, the Corps will make a final decision on whether to allow the project to proceed. Approval is expected.
That will almost certainly not be the end of the story, however.
Even after the Corps’ latest review, “the E.I.S. is so lacking and thoroughly inadequate, I anticipate legal challenges,” said Brian Litmans, legal director of Trustees for Alaska, a nonprofit public interest law firm.
The project will require more permits, mostly from the state, which could take three years to obtain. And should President Trump lose re-election, a Democratic administration could move to block the project once again.
In Alaska, statewide public opinion polls have consistently shown more opposition than support, and locally the anti-mine feelings are even stronger. “Opposition is overwhelming throughout the bay,” Mr. Litmans said.
Opponents are focusing on an 11th-hour change to one aspect of the project. In May, the Corps announced it had changed its determination of what is called the “least environmentally damaging practicable alternative” for the transportation route between the mine and Cook Inlet.
The company and the Corps had both favored a route that included a ferry crossing of Iliamna Lake, one of the largest in the United States. But after hearing concerns about the potential impact on winter travel and seal hunting on the lake, the Corps now says a land-only route, along the northern edge of the lake, is the preferred one, although it could destroy several thousand acres of wetlands.
The Bristol Bay Native Corporation, one of 13 regional corporations established in the 1970s in the settlement of Native claims to Alaska’s lands, owns subsurface rights on land that the route would cross.
“We believe the subsurface will be impacted” by construction of a road and pipelines, said Daniel Cheyette, the corporation’s vice president for land and resources. “We’ve not given Pebble permission to utilize those or impact those.”
As to whether the corporation might negotiate on the issue, Mr. Cheyette said that while he could not speak for his board of directors, “I believe that is nonnegotiable.”
“We’ve been fighting this for a long time and will continue to fight it,” he said.
Other Alaska Native groups, including the village corporation of Pedro Bay on Iliamna Lake, also plan to withhold access to their lands.
But not all Native groups are opposed to the project.
A consortium of five village corporations in the area expects to become a transportation contractor for the mine. And the village corporation for Iliamna, about 20 miles from the mine site, has already negotiated with the developer to allow access to 68,000 acres of land it owns.
“We don’t see Pebble damaging the area like everybody claims,” said Lisa Reimers, a board member of the corporation, Iliamna Natives Ltd. “Pebble has to do it right because there are so many people watching them.”
Ms. Reimers was raised in Iliamna, in a house that had no running water or electricity until she was 12. Her parents, she said, “wanted the best for their family and for their grandkids today.”
“They didn’t see Iliamna surviving without a project like Pebble.”