Last week, The Army Corps of Engineers released its Draft Environmental Impact Statement for the enormously controversial Pebble Mine. For those of you not familiar with Pebble Mine, it is a proposed open-pit copper, gold, and molybdenum mine, which—if approved—would become the largest mine in North America. Managed by the Pebble Limited Partnership (PLP), the mine would be located in close proximity to Bristol Bay’s famed headwaters: the Kvichak and Nushagak Rivers—both highly productive salmon spawning grounds. The proposed mine would operate for 20 years, remove 1.3 billion tons of material, and disrupt the wild environments of this Southwestern Alaskan region. PLP claims their mine operation will pose NO risks to this wild region: no risks from pyritic tailings; no failure risks; and, the area’s habitat will be IMPROVED from its natural state. Yet, accidents happen, and mitigation plans fail.

Environmental Impact Statements are an essential component of United States environmental law and policy. They identify for the public the environmental impacts of a proposed project for a given area. In the case of Pebble Mine, a Draft Environmental Impact Statement (DEIS) was released to the public on February 20th. As is standard practice, the DEIS will be subject to a period of public discussions and comment. Those opposing Pebble Mine have only 90 days to submit comments and attend public hearings.

Critics of both Pebble Mine and this specific DEIS say that this comment period is completely inadequate. Alaskan Senator Lisa Murkowski said, “I am looking at (the report) and saying, I think, given the size and scope, and again the Alaskan interest, the public interest in this, it’s probably not going to be sufficient,” in an Anchorage Daily News interview. When you understand the technical nature of both the Pebble Mine proposal and the nearly 1,400-page DEIS, it becomes obvious that the public needs more time. The public comment period will run from March 1, 2019 through May 30, 2019.

Watersheds potentially impacted by Pebble Mine

You can submit comments here. Additionally, comments may be submitted through testimony at public meetings, email them to, or call Shane McCoy of the Army Corps of Engineers at 907-753-2715 to make your opinion heard. We urge you to submit a comment, as this is an important battle for fishermen, the health of Alaska’s fisheries, and Alaskan communities.

This DEIS is a dense, complicated document, leaving many stakeholders scratching their heads. Based on the complexity of the DEIS, the relatively short comment period should be extended so that the public and interested stakeholders have sufficient time to digest it and provide informed comments. With an extended public comment period, stakeholders can conduct essential independent analyses, identify contradicting data, and achieve complete public understanding. Follow along to better understand the devastating effects Pebble Mine could have on Bristol Bay.

Executive Summary:

It is also important to note that the DEIS looks at the potential impacts of four Pebble Mine ‘Alternatives’. This analysis, however, examines the implications of Action Alternative 1, which is the base Pebble Limited Partnership alternative. The DEIS also identified a No Action Alternative: the comparative baseline where none of the identified impacts would occur. Broadly speaking, the DEIS Executive Summary identifies these expected impacts as:

  • “Physical loss of stream, lake, estuarine, and marine habitat
  • Blockage of stream channels preventing fish or other aquatic species passage
  • Aquatic habitat effects due to instream flow reductions from mine water withdrawal or capture, and redirection of groundwater.”

Keep reading for a more in-depth analysis of the complex impacts identified in the DEIS Executive Summary.


One of the many concerning provisions of Alternative 1 is the production of massive amounts of mine tailings—essentially the mine waste that is not of economic importance to the mine operation. Alternative 1 would require two tailing storage facilities (TSFs): approximately 2,796 acres for bulk tailings and 1,071 acres for pyritic tailings, both of which would be located predominantly in the North Fork Koktuli river (NFK) watershed with a small footprint in the South Fork Koktuli river (SFK) watershed. Both of these TSFs present a significant threat to Bristol Bay’s watershed. The TSFs will be constructed in the form of a massive earthen dam—the largest in the world. This dam would be vulnerable to a breach, given the seismic activity of the region. Additionally, the structural integrity of the proposed earthen dam has been questioned by independent scientists.

A digital simulation of Pebble Mine Alternative 1 from the DEIS, Ch. 2

The pyritic tailings represent the most concerning aspect of the TSFs. Pyritic tailings contain material that—when exposed to oxygen and water—can produce acid mine drainage (AMD). When it enters a watershed, AMD can alter its pH and have degrading effects on the connected environments. The perceived seriousness of the TSFs varies between the DEIS, PLP, and Save Bristol Bay, amplifying the controversy and criticism of the DEIS and Pebble Mine. wrote, “preliminary geochemical data indicates significant acid mine drainage potential at Pebble,” and “authorizing a mine where it is known that water treatment in perpetuity will be required poses significant long term financial and/or environmental risks to the public”. The potential for AMD is high throughout the Pebble Mine footprint, threatening the environment and public for hundreds of years.


Currently, these watersheds are undisturbed, but the DEIS outlines many troubling hydrologic impacts from Pebble Mine. During the initial construction, surface water in the NFK and SFK watersheds would be affected by diversion, collection of groundwater, and influx of ‘dirty’ water. Tributary 1.19 of the NFK, located within the mine site footprint, would be permanently blocked from construction and not restored. Additionally, the Executive Summary identifies long-term impacts to the streamflows of the NFK, SFK, and Upper Talarik Creek (UTC), continuing into the closure and post-closure stages (20+ years) of Pebble Mine.

Goodnews River Lodge, located North of Bristol Bay

The primary goal of water management for Pebble Mine would be, “to manage runoff and minimize surface water contact with disturbed surfaces”. While Alternative 1 includes strategies for minimization of environmental impacts—TSFs among other strategies in accordance with state and federal regulations—accidents and failures do happen. Finally, it is inescapable that Pebble Mine’s goals and intentions are inconsistent with sound environmental practice; the hydrology of Bristol Bay would be systematically affected, disrupting the entire connected ecosystem.


The DEIS Executive Summary goes on to describe the impacts to fisheries. The NFK watershed, including its many tributaries, is valuable habitat for most species of Pacific Salmon. The Executive Summary identifies spawning habitat for chinook, coho, and Sockeye salmon within the NFK watershed and directly downstream from the mine site. Additionally, Tributary 1.19 of the NFK, which provides essential spawning and rearing habitat for chinook and coho salmon and resident fish (rainbow trout, dolly varden, and arctic grayling), would be permanently destroyed through mine site construction. Similarly, the open-pit mine and associated facilities will permanently impact two miles of fish habitat on the upper main stem SFK.

A nice Arctic Grayling. These beautiful fish would potentially be harmed by Pebble Mine.

Reduced streamflows for the NFK, SFK, and UTC are fully expected because of mining activities. This reduction represents a major disruption to the area within the mine site footprint—totaling 8,086 acres—but also will inevitably alter downstream levels. According to the Executive Summary, “chinook and coho spawning habitat would be reduced,” during average precipitation years. So, to sum-up some of these expected fisheries effects, the proposed Pebble Mine Alternative 1 will significantly disrupt previously pristine watersheds; permanently destroy salmon and resident fish habitat; and in a worst-case scenario, leach 1,071 acres of potentially acid generating pyritic tailings into the connected waters.

A brute Alaskan Chinook salmon. This species would lose essential spawning and rearing habitat due to Pebble Mine

As recreational and commercial fishing are concerned, the effects identified above would directly impact these Alaskan industries. Due to necessary supporting infrastructure for Alternative 1, “the change in fishing experience could be perceived as a permanent adverse impact for those anglers expecting a wilderness experience,” per the DEIS Executive Summary. Similarly, any diminishment of salmon harvests due to habitat loss would affect Bristol Bay’s essential commercial salmon fishing economy. The Wild Salmon Center wrote, “economic evaluations promoting mine development do not adequately account for the value of healthy ecosystems or the long-term costs associated with large mine clean-up”.

Bristol Bay’s commercial fishing industry produced $493 million in total economic impact (annual average 2013-2017), according to the Economic Benefits of The Bristol Bay Salmon Industry. This economic estimate does not include the many positive impacts from sportfishing, including 102 guiding businesses and many other tourism-related benefits. Conversely, Pebble Mine would result in 1,500-2,000 jobs with an average mining wage of $100,000 for Alaskans, according to PLP. Shouldn’t this sustainable and amazing fishery be protected? Sure, Pebble Mine will bring economic value to the region during its operation, but at some point the potential risks must outweigh any temporary economic benefits.

Goodnews River Lodge from above

If you are still reading, I hope you realize the depth, complexity, and controversy of the proposed Pebble Mine. While there may be a pro-pebble mine bias—as many outlets are claiming—the bigger issue is just how difficult documents like this DEIS are to understand. Stakeholders have to wade through so much muck and technical terminology, before they can even come close to realizing the potential impacts of Pebble Mine.

Yes, the DEIS Executive Summary, all 80 pages of it, contains language attempting to diminish the perceived effects of Pebble Mine. No, I do not think that this was a fair assessment. But yes, the Executive Summary provides readers, who are willing to go the extra mile, important information about how Pebble Mine will disrupt and harm Bristol Bay fisheries and environments.

Be sure to check out for more information about the fight over Pebble Mine and its potentially devastating impacts.

If this analysis has convinced you that Pebble Mine would devastate Bristol Bay and its salmon, submit a comment to the Army Corps of Engineers by clicking here.

Also, if you are still confused about the implications of the DEIS or Pebble Mine, please leave a comment, and we will attempt to provide adequate answers. We will be posting Pebble Mine updates as they arise.

This article was written by Flylords Team Member Will Poston.

Here are some previous Flylords Pebble Mine articles:

RepYourWater Releases New Bristol Bay Buff: 50% of Proceeds to Fight Pebble Mine

Step Up and Help Save Bristol Bay!

2017 politics going pro-Pebble Mine