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Kerr-Sulphurets-Mitchell (KSM) Mine

The KSM is the largest of several open-pit mines proposed for the Alaska/British Columbia transboundary region.  Rapid industrial development is expected for this region of Canada, powered by the new Northwest British Columbia Transmission line.  The KSM is comparable to the size and scope of the Pebble Mine proposed in Bristol Bay (see fact sheet for comparison info).

The site of the proposed mine is just 19 miles from the Alaska border, on Sulphurets Creek, a major tributary of the Unuk River.  The Unuk flows into Behm Canal and Misty Fjords National Monument.  The Unuk River is among the top salmon producing rivers in Southeast Alaska.


Mine Details

As proposed, this mine will be among the largest open-pit mines in the world.  It will process 130,000 tons of ore per day.  (For comparison the Greens Creek Mine processes 2,200 tons per day).  The mine will operate for 52 years.

Waste Rock: The KSM will produce 2.5 billion tons of acid producing waste rock that will be dumped into the Mitchell and McTagg Valleys just above the Unuk River.

Pits: The open pits will cover 2,500 acres and be over 1,200 feet deep.  Pumping water from the pits will essentially remove all of the ground water from the mine footprint.

Waste Water: The mine will be required to treat 119,000 gallons of contaminated water per minute prior to dumping into the Unuk River.  This scale of water treatment is unprecedented.  An earthen dam 540 feet tall will contain the lake of contaminated water.  Water will have to be treated for at least 200 years after closure and possibly forever.

Tailings Dump: The tailings dump will cover 3,400 acres of fish habitat in the headwaters of the Bell-Irving river system.  This sludge will be contained behind a 2 dams over 700 feet tall; taller and wider than the Hoover Dam.  These dams will be made from waste rock, not concrete.


What to Do

The KSM is currently being reviewed for certification by the BC Ministry of Environment.  Permits could be issued as soon as April 2014.

Thanks to the work of SEACC, the U.S. State Department has become aware of the threat this mine and other transboundary developments pose to Southeast Alaska commercial fishing, communities and Tribes.  These groups are united in their opposition to this project.

The U.S. State Department needs to hear from our congressional delegation.  Tell Senators Murkowski and Begich and Reprehensive Young that projects of this size should be elevated to diplomatic levels to protect Southeast Alaska rivers, fish and communities.

Sen. Mark Begich: (202) 224-3004

Sen. Lisa Murkowski: (202) 224-6665

Rep. Don Young: (202) 225-5765




Audit of the British Columbia Office of Environmental Assessment Office, July 2011.

From the audit:

"When major projects such as mines, dams or tourist destination resorts are undertaken in the province, British Columbians expect that any potentially significant adverse effects (whether environmental, economic, social, heritage and/or health related) will be avoided or mitigated. The Environmental Assessment Office is expected to provide sound oversight of such projects. However, this has not been happening. The audit found that the Environmental Assessment Office cannot assure British Columbians that mitigation efforts are having the intended effects because adequate monitoring is not occurring and follow-up evaluations are not being conducted. We also found that information currently being provided to the public is not sufficient to ensure accountability."


KSM Project Information Center, including links to various project permit applications and documents, Province of British Columbia.

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