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EPA Releases Revised Bristol Bay Assessment/Agency asks for Additional Peer Review and Public Comment

Release Date: 04/26/2013
Contact Information: Marianne Holsman,, 206-553-1237

SEATTLE -- The U.S. Environmental Protection Agency (EPA) has released a revised version of the Bristol Bay Assessment for peer review follow-up and public comment. The assessment released today includes updates following an initial peer review and public comment period of the draft Bristol Bay Assessment released in May, 2012. EPA is arranging for the original independent, scientific peer reviewers to evaluate the revisions made following their feedback. EPA is also inviting the public to submit comments until May 31, 2013.

The peer review follow-up and comment period are meant to ensure that EPA is using the best available science for its assessment, and that information from a range of stakeholders is considered, including industry, conservation groups, and Tribes. The revised assessment reflects feedback from the initial peer review report and 233,000 public comments EPA received when it released the original assessment.

Key changes to the assessment include:

Refinement and better explanation of the mine scenarios assessed, including the role in developing these scenarios of worldwide industry standards for porphyry copper mining and specific preliminary mine plans submitted to state and federal agencies related to the Pebble Mine Project.

- Incorporation of modern conventional mining practices into mine scenarios and clarification that some of the projected impacts assume that those practices are in place and working properly.

- Addition of an appendix describing methods to compensate for impacts to wetlands, streams and fish.

- Reorganization of the assessment to better reflect the ecological risk assessment approach and to clarify the purpose and scope.

- Additional details about projected water loss and water quality impacts on stream reaches, drainage of waste rock leachate to streams, and mine site water balance to assessment of potential mine impacts.

Expanded information on the potential transportation corridor, including analysis of potential diesel pipeline spills, product concentrate spills, truck accidents involving process chemicals and culvert failures.

The public comment period ends May 31, 2013.

EPA released the draft Bristol Bay Assessment on May 18, 2012. The agency held a series of public meetings concurrent with the release and received feedback from 12 independent expert peer reviewers.

In February 2011, in response to growing interest in large-scale mining in the watershed from a number of stakeholders and local communities with a range of views, EPA launched the Bristol Bay assessment to gain a better understanding of the watershed and the potential impacts of large-scale mining in the area. The assessment provides a scientific foundation for future decision-making by federal and state agencies and to inform public discussion. EPA has made no decisions about using its Clean Water Act authorities in Bristol Bay.

After this peer review follow-up and public comment period are complete, EPA will review feedback and move forward to finalize the assessment. EPA intends to issue a final assessment in 2013.

To review the revised assessment, for instructions how to submit comments, and to learn more about the Bristol Bay Assessment, visit: