by Sarah Childress

The massive British mining company said on Monday that its U.S. subsidiary would withdraw from the controversial Pebble copper mine project in Alaska in order to focus on projects with lesser risks.

“Despite our belief that Pebble is a deposit of rare magnitude and quality, we have taken the decision to withdraw following a thorough assessment of Anglo American’s extensive pipeline of long-dated project options,” Mark Cutifani, the chief executive, said in a statement. “Our focus has been to prioritize capital to projects with the highest value and lowest risks within our portfolio.”

The move comes as the Environmental Protection Agency is considering whether to allow the mine, which is estimated to hold more than $200 billion in copper and other metals, to move forward.

FRONTLINE explored the debate over the Pebble mine in Alaska Gold. The proposed project would be one of the largest open-pit mines in the world.

But the mine would also be built next to the world’s largest sockeye salmon-production system — the pristine salmon fisheries of Bristol Bay, Alaska. Some environmental scientists worry the billions of tons of waste it would produce could threaten the delicate ecosystem that salmon depend on to thrive.

The Pebble Partnership has argued that it can appropriately contain the waste and that the mining operations wouldn’t harm the fish. But the EPA isn’t so sure.

A critical preliminary EPA study (pdf) released earlier this year suggested the agency has serious concerns about the mine, including the potential for pipeline failures and leakage from the water treatment plant.

Gina McCarthy, the administrator chosen to lead the EPA in August, recently visited the area and seemed moved by residents’ testimony against the mine.

“EPA is going to make our decision based on what our legal authority is — no over-stretches — and on what the science says and real data,” McCarthy told the Anchorage Daily News.

It’s unclear what kind of impact Anglo American’s withdrawal might have on the mine. Northern Dynasty Minerals Ltd., the Canadian partner company, is now the sole owner of the project and said in a statement that it would move forward.

“Northern Dynasty and the Pebble Partnership have both the expertise and resources necessary to advance the Pebble Project,” Ron Thiessen, Northern Dynasty’s chief executive, said in a statement.

Delve into the debate in our film — watch it here.