The proposed pebble mine: Identified risks to Alaskan fisheries

Persistence of North American wild salmon in the "lower 48" and Canada is uncertain.  In contrast, over 40 million wild salmon returned to Bristol Bay, Alaska, in 2009.  Bristol Bay is the world’s most valuable commercial fishery and one of its few remaining salmon strongholds.  Mining interests have claimed over 1,750 km² (~677 mi²) in area headwaters.  The Pebble prospect, a low-grade (<1% CuEQ) copper-gold-molybdenum porphyry deposit, is located under salmon habitat straddling two major Bristol Bay drainages.  It's estimated 10.78 billion tons of ore would be mined using open-pit and block caving methods.  Over 99% of mined material would remain as waste to be stored on site forever.  Salmon conservation concerns revolve around water quality and quantity: loss of currently productive salmon streams from mine development; the high potential for acid generation from the deposit's iron sulfides,  leaching metals into ground and surface waters; and perpetual storage of contaminants behind earthen dams in a seismically active region prone to floods.  The prospect's estimated 55 billion pounds of copper are a conservation concern because legal increases in copper to local waters can harm: salmon olfaction, a key sense for survival; zooplankton, a primary food for young sockeye salmon; and freshwater mussels, a prime food of whitefish that are an important local subsistence food.  The Pebble Limited Partnership anticipates applying for permits in 2011.

 

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