On April 26, 2013, more than 300 leading scientists sent a letter to the White House expressing "deep concerns" about the prospect of large-scale mining in the Bristol Bay watershed of Southwest Alaska, home to the world's largest wild salmon runs. The action comes as the Environmental Protection Agency (EPA) releases for public comment a revised draft assessment on watershed impacts of what could be North America's largest mine.

(Click on audio mp3 above to hear more about the proposed mine in an interview with Dr. David Chambers, a geophysicist with the Center for Science in Public Participation.)

The open-pit gold and copper operation, known as Pebble Mine, would likely cover an area larger than Manhattan, according to EPA. The proposal is backed by the world's second-largest mining corporation, London-based Anglo American, and Canada's Northern Dynasty Minerals. The project has drawn sharp criticism from the Bristol Bay Native Corp., nine regional tribes, the commercial fishing industry, sportsmen, and environmentalists who fear the massive mine could cause irreversible damage to the watershed. The state of Alaska and the mining industry have objected to EPA's action to assesses the mine's potential impact.

In 2009, Bristol Bay Native Corp. and nine tribes called on EPA to use its authority under the Clean Water Act to declare the watershed off-limits for mine waste disposal. EPA responded with a draft Bristol Bay watershed assessment in May 2012, concluding that "mining at this scale would cause the loss of spawning and rearing habitat for multiple species of anadromous and resident fish." On April 26, 2013, EPA released a revised draft for a 30-day public comment period. The new version is designed to address peer-review comments on the agency's May 2012 draft.

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