WASHINGTON — The Environmental Protection Agency has settled an ongoing lawsuit with the Pebble Limited Partnership and says the company can apply for a federal permit for its proposed massive gold and copper mine in the Bristol Bay watershed.

Friday's announcement reverses the Obama administration's efforts to prevent progress of the world's largest undeveloped trove of gold and copper. The settlement ends several legal battles ongoing since the EPA issued a proposed determination in 2014 that would have put the area off-limits for a federal mining permit.

Salmon fishermen, Alaska Native organizations in the Bristol Bay region and environmental groups have been fighting the proposed gold, copper and molybdenum mine for more than a decade, saying it imperils the world's largest salmon run, a significant source of income for Alaskans. The groups said they were dismayed by the Trump administration's decision.

Mining advocates say the gold alone is worth more than $300 billion, and that the federal government should allow the process to advance without early intervention from the EPA. Mine companies have already spent roughly $800 million on the project.

EPA Administrator Scott Pruitt said early Friday that the agency is committed to allowing the process to move forward, but isn't prejudging the outcome.

"We understand how much the community cares about this issue, with passionate advocates on all sides," Pruitt said. "The agreement will not guarantee or prejudge a particular outcome, but will provide Pebble a fair process for their permit application and help steer EPA away from costly and time-consuming litigation. We are committed to listening to all voices as this process unfolds."

The new approach promised by the Trump administration offers significant hope for the Pebble mine purveyors, but the process ahead will take years. Depending on the timing of the permit application, federal review and public input, the ultimate decision could easily sit with a new administration if President Donald Trump is not re-elected in 2020.

The Pebble Limited Partnership plans to recast its plans, focusing on a smaller mine footprint, requiring new field data and infrastructure plans. And the company needs new investors, a process which could slow plans to apply for a permit by years. Funding partners for parent company Northern Dynasty Minerals pulled out of the project in 2013.

Ron Thiessen, president of Northern Dynasty Minerals Ltd., the sole current owner of the Pebble Limited Partnership, said the mine company is now planning a "smaller project design at Pebble than previously considered, and one that incorporates significant environmental safeguards."

Opponents to the mine were not swayed by promises of a smaller mine footprint.

"Pebble can tell you what they want, you just need to look on their website, they're going to mine it until the end until the last dollar until they can extract the last dollar out of that resource," said Russell Nelson, committee chairman for Bristol Bay Native Corp. "They can tell you it's small, but look at the cost of developing. They need to get their money out. They're in it for the money."

Bristol Bay Native Corp. was one of several Native organizations that went to the EPA for help stopping the mine, which led to the agency's proposed determination that the mine could not likely be built without significant damage to important salmon spawning waters in the Bristol Bay watershed.

Since then, Pebble and the EPA have been mired in litigation.

As part of the agreement, the EPA will be allowed to use "use its scientific assessment regarding the Bristol Bay Watershed without limitation," the agency said in a statement. It is not clear just how they will use it.

On Friday, Pebble and the Justice Department jointly asked the U.S. District Court in Alaska to dismiss ongoing litigation.

The EPA plans to soon start the process of withdrawing its proposed regulation.

The EPA said it agreed to hold off on any follow-up to its proposed determination until four years after the settlement "or until the U.S. Army Corps of Engineers issues its final environmental impact statement, whichever comes first."

Pebble Partnership CEO Tom Collier said the four-year time limit was meant to follow a federal standard known as the "Meese Rule," by avoiding a settlement that constrains federal discretionary authority. The Justice Department wanted a set time period, he said.

Pebble, in exchange, will have to file its permit application within 30 months (2 1/2 years).

Pebble claimed for years that its permit application was imminent, but never filed. Once the EPA got involved and made its determination, after crafting an assessment of the watershed where the proposed mine would be, the mine company said they would have to wait until litigation was resolved.

Pebble also agreed to drop its lawsuits and fee requests in the courts, and agreed it wouldn't file any more Freedom of Information Act requests for several years, according to the EPA.

The mining company was thrilled with the turnabout offered by the Trump administration.

"From the outset of this unfortunate saga, we've asked for nothing more than fairness and due process under the law — the right to propose a development plan for Pebble and have it assessed against the robust environmental regulations and rigorous permitting requirements enforced in Alaska and the United States," Thiessen said.

Pebble Partnership CEO Tom Collier promises changes on behalf of the mine company going forward. "Not only will we be rolling out a project that is smaller, with demonstrable environmental protections, we will also be announcing a number of new initiatives to ensure our project is more responsive to the priorities and concerns of Alaskans," Collier said.

Thiessen and Collier were optimistic Friday that the company would easily find new investors, speaking on a call with analysts. The Alaska deposits offer a politically stable environment, compared to many African mines; there is no permafrost; the deposit is near tidewater and Asian markets; the assets are of a coveted kind; and the mining industry has regained an interest in partnered projects, Thiessen said.

"I feel very confident that there's a very high level of interest in the project," Thiessen said.

When it comes to filing a federal permit application, Northern Dynasty is "ready to jump on it with vigor," Collier said. But the company expects to take a few years to give potential new partners time to weigh in first.

But Northern Dynasty firmly expects a speedy permitting process to come out of the Trump administration, Collier and Thiessen said Friday. They said they expect it to be one of the first projects to go through an expedited permitting process, which would allow them to complete the process in "record time."

Native, environmental and sportsmen's groups were distraught at EPA's change in direction.

"There were literally dozens of public hearings. Thousands of people in Bristol Bay testified and spoke. Tens of thousands of people in the state of Alaska spoke. Hundreds of thousands of people in the U.S. spoke," said Norman Van Vactor, president of Bristol Bay Economic Development Corp. He said that stood in stark contrast to Friday's decision, an agreement between "bureaucrats and foreign mining executives."

Leaders from Bristol Bay Economic Development Corp., tribes and Native corporations groups all expressed a sense of exhaustion with the decadelong fight, but pledged to continue their efforts to stop the mine.

Robin Samuelsen, Curyung tribal council chief and a commercial fisherman, said he would "continue to fight Pebble for as long as Pebble wants to build a mine in Bristol Bay. I'm 66 years old and I'll give it my last breath."

"Endangering America's greatest salmon fishery to enrich a mining conglomerate shows Pruitt's complete contempt for the EPA's mission," said Brett Hartl, government affairs director with the Center for Biological Diversity. "This massive mine will be a catastrophe for the people and environment of Bristol Bay and the whole state of Alaska."

"The sport fishing community, which supports a $250 million-a-year economy in the Bristol Bay region, depends upon the continued sustainable health of the region in order to operate our businesses," said Brian Kraft of Alaska Sportsman's Lodges. "The science behind the EPA's proposed determination has been through two massive peer reviews and countless public testimony."

Nelli Williams of Trout Unlimited in Anchorage said the project would risk thousands of jobs and "half the world's sockeye salmon." Williams said the group will "be looking to our elected officials and decision-makers to ensure they don't turn their back on the people of Alaska. We have said, and will continue to say, that Pebble is not welcome here. Alaskans aren't going anywhere, we are in this fight for the long haul."

But reactions from Alaska's congressional delegation were mixed. All three said that EPA should not stand in the way of the permitting process, but that protecting fisheries should be a priority. The senators also expressed overall reservations about the Pebble mine project.

U.S. Sen. Dan Sullivan said that he has always held concerns about the EPA's proposed "pre-emptive veto of a potential economic development project on state land" and thought it could set "a precedent that could undermine jobs and economic opportunities in other parts of Alaska."

But he was clear that Alaska "will not trade one resource for another" (copper for fish), and said he "reiterated this in a discussion with EPA Administrator Scott Pruitt last week."

Sullivan said he also shared concerns held by Alaskans in the Bristol Bay region, "including tribes, health officials, fishermen and community leaders — regarding the delicate environmental balance that exists within the Bristol Bay Watershed."

Sen. Lisa Murkowski reiterated opposition to swapping resources, and "advocated for a fair and consistent permitting process," through spokeswoman Karina Petersen.

But it "is critical for Pebble to tell Alaskans whether and how they will proceed — the company's failure to do so thus far has created uncertainty and anxiety among" Alaskans, Petersen said. "If Pebble intends to move forward with this project, it should enter the permitting process expeditiously so that all stakeholders can have the details needed to make informed decisions about a potential mine," Petersen said. And, she added, "if the company can't prove the mine will be safe, the mine shouldn't be built."

Congressman Don Young had strong words for the Obama EPA, saying the agency's "pre-emptive veto" of the project made "a mockery of the federal permitting process" and that "it sent a chilling message to any and all future development in Alaska — on state and private lands."

"If allowed to stand, this tactic would have been used across our state and nation to kill countless projects requiring (similar) permits. Ultimately, I believe this process should be allowed to move forward — permits should be filed and scientific reviews should take place," Young said. The EPA cannot be allowed "unilaterally dictate what we can and cannot do on state lands," he said.

Young also said that he understands the "sensitivity surrounding this project," and that if fisheries cannot be protected, it should not be done.

Washington Sen. Maria Cantwell wrote Pruitt earlier this week after catching wind of a potential settlement between the EPA and Pebble, urging the administrator to consider the consequences.

"The proposed Pebble Mine is a direct threat to those jobs, and the Pacific Northwest economy, which is why the agency recommended that common-sense restrictions be put on large scale hard rock mining development in the headwaters of Bristol Bay," Cantwell wrote.