Assessment Says Large-Scale Mine Could Be Disastrous to Salmon

By Margaret Bauman

A final Bristol Bay watershed assessment released Jan. 15 by the US Environmental Protection Agency says a large scale copper, gold and molybdenum mine in the Bristol Bay watershed could have catastrophic effects on fishery resources.

The report describes potential impacts to salmon and ecological resources from the proposed large-scale mine, concluding that the mine poses extensive risks to salmon and Alaska Native cultures. Bristol Bay, with annual runs averaging 37.5 million fish, produces nearly 50 percent of the world’s wild sockeye salmon.

The complete report is online at www.epa.gov/bristolbay.

The EPA said the report would serve as a technical resource for governments, tribes and the public to consider how to address challenges of large-scale mining and ecological protection of the Bristol Bay watershed.

The report says that depending on the size of the mine, the EPA estimates 24 to 94 miles of salmon supporting streams and 1,300 to 5,350 acres of wetlands, ponds and lakes would be destroyed. EPA estimates an additional 9 to 33 miles of salmon supporting streams would experience altered stream flows likely to affect ecosystem structure and function. Large quantities of mine waste, leachates and wastewater would have to be collected, stored, treated and managed long after the mining is concluded and under routine operations, EPA estimates adverse direct and indirect effects on fish in up to 51 miles of streams.

The report said failure of a tailings storage facility dam that released only a partial volume of stored tailings would have catastrophic effects on fishery resources. Consistent with recent record of petroleum pipelines and similar mines operating in North and South America, pipeline failures along the transportation corridor could release toxic copper concentrate or diesel fuel into salmon supporting streams or wetlands. A transportation corridor to Cook Inlet would cross wetlands and some 64 streams and rivers in the Kvichak River watershed, 55 of which are known or likely to support salmon.

Culvert failures, runoff, and spills of chemicals would put at risk salmon spawning areas in and near Iliamna Lake, the report said.

EPA also estimates failures in water collection and treatment are possible, and would have adverse effects on fish in 48 to 62 miles of streams.

The assessment found that the Bristol Bay ecosystem generated $480 million in economic activity in 2009, while providing employment for over 14,000 workers. The region also supports all five species of Pacific salmon found in North America, and is home to more than 20 other fish species, 190 bird species and more than 40 terrestrial mammal species, including bears, moose and caribou.