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EPA in Alaska's Bristol Bay: Questions and Answers

  • Author: Eric Adams
  • Updated: September 27, 2016
  • Published August 8, 2012

Engineers, biologists, nonprofits, policymakers and a gaggle of media have descended on downtown Anchorage to discuss the controversial draft Bristol Bay watershed assessment. On Wednesday, independent scientists tasked with reviewing the EPA assessment debated 14 specific questions about the impact of mining on the region.

Stay tuned: Alaska Dispatch will have a full story on the scientific debate. Meantime, here are a few questions and answers to better understand why the EPA is here reviewing the mine before any project has been proposed, and some other interesting points to consider:


Q: Why is the Environmental Protection Agency studying Bristol Bay's watershed and what, if any, impact large-scale mining might have to salmon habitat?

A: In May 2010, at least nine Alaska tribal groups and one Alaska Native regional corporation petitioned the EPA to assess whether a large-scale mining project in Southwest Alaska's Bristol Bay watershed would adversely impact fish, wildlife, water quality or Alaska Native culture. Source: Dennis McLerran, the EPA Region 10 administrator for Alaska, Idaho, Oregon, Washington and 271 Native tribes.


Q: What was the aim of the petition?

A: The petitioners asked the EPA to use its regulatory authority under Section 404(c) of the U.S. Clean Water Act to veto the proposed Pebble Mine prospect -- thought to be the among the world's largest undeveloped deposits of gold, copper and molybdenum. Source: McLerran

Section 404(c) authorizes EPA to "restrict, prohibit, deny or withdraw the use of an area as a disposal site for dredged or fill material if the discharge will have unacceptable adverse impacts on municipal water supplies, shellfish beds and fishery areas, wildlife or recreational areas."


Q: How long has Bristol Bay watershed been studied, and by whom, since the EPA became involved?

A: Eighteen months. The assessment involves scientists from the EPA, the state of Alaska, the U.S. Army Corps of Engineers and others. Source: McLerran


Q: How long has the Pebble Limited Partnership (Anglo American Plc and Northern Dynasty Minerals) been studying the deposit's environment?

A: Eight years of studying the Bristol Bay watershed surrounding the deposit, work that the companies say cost about $200 million. Source: John Shively, Pebble Limited Partnership CEO


Q: Does the EPA assessment incorporate the years of data analysis and compilation already undertaken by Pebble? Why or why not?

A: No. Pebble submitted thousands of pages of data on Bristol Bay's watershed and salmon habitat. It's standard practice for scientists to seek independently-verified analysis of data. EPA welcomed any information that would help in its analysis of the watershed; however, the Pebble data was offered in an unacceptable form. Source: McLerran


Q: How biologically diverse is the Bristol Bay watershed?

A: Bristol Bay watershed provides habitat for numerous animal species:

  • More than 190 bird species, including nearly a half-million ducks, 7,700 geese, 15,400 swans and 5,300 sandhill cranes.
  • More than 40 species of terrestrial animals, including caribou, moose and brown bear.
  • More than 35 species of fish, including rainbow trout, Arctic grayling, Dolly Varden char, Chinook salmon, sockeye salmon, coho salmon, chum salmon and pinks. Source: EPA Draft Bristol Bay Assessment
  • ==

    Q: Pebble hasn't submitted a mine development proposal. How did the EPA assess a mine that hasn't yet been developed?

    A: EPA developed a hypothetical mine scenario, based on mining of the Pebble deposit and data provided by Northern Dynasty Minerals (co-owner of the Pebble deposit), among other mining firms. The mine draws on plans published by Pebble Limited Partnership and ... reflects general characteristics of Bristol Bay watershed mineral deposits, contemporary mining technologies and some theoretical infrastructure development that such a large project might require. Source: EPA Draft Bristol Bay Assessment Executive Summary


    Q: How much gold and copper is the Pebble deposit believed to hold?

    A: Pebble engineers believe there's at least 100 million recoverable ounces of gold and 80 billion pounds of recoverable copper beneath a mile-and-a-half-wide swath of swampy tundra, some 20 miles from Lake Iliamna, the largest lake in Alaska and eighth-largest lake in North America. Source: Jane Whitsett, Pebble environmental studies manager (2011 interview)


    Q: What type of infrastructure might a future Pebble Mine require?

    A: Because the region is off Alaska's road system, significant investment in infrastructure projects would be required. Here are a few of the projects expected:

  • A deepwater port to service the mine;
  • An 80-mile road connecting that port to the Pebble deposit;
  • Four pipelines running along the road;
  • Ore processing facilities;
  • A power plant big enough to "electrify Anchorage";
  • Arrangements for a 3,286-acre waste rock pile. Millions of tons of waste rock will be produced;
  • Arrangements for a 3,686-acre tailings impoundment behind a 685-foot-high earthen dam.
  • Sources:


    Q: Is the EPA's Bristol Bay watershed assessment complete?

    A: No. EPA hopes to complete the assessment by the end of the year. Source: McLarren


    Q: Will any regulatory recommendations or actions result from the assessment?

    A: EPA says it's too early to comment on what their recommendation or action will be with data still being gathered. Source: McLarren

    Contact Eric Christopher Adams at eric(at)

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