The South Fork Salmon River is one of Idaho’s most ecologically important watersheds. The river and its tributaries like the East Fork South Fork provide critical habitat for Chinook salmon, steelhead and bull trout. The surrounding mountains provide important denning habitat for wolverines. Much like a younger, scrappier sibling of the Middle Fork Salmon River, the South Fork also provides world-renowned whitewater recreation opportunities. Sadly, the East Fork South Fork suffers from historic mining pollution with the Stibnite mining area in its headwaters, and the area faces another huge threat with a newly proposed project – the Stibnite Gold Project. Mining company Perpetua Resources is in the advanced stages of permitting a massive open-pit cyanide vat leach mine at the Stibnite site, raising alarm for all that rely on and enjoy this area. In a series of blogs, we investigate the impacts of this project on our beloved public lands, water, fish and wildlife, public health, and recreation opportunities.

In late October, the U.S. Forest Service released its Supplemental Draft Environmental Impact Statement (SDEIS) for the proposed Stibnite Gold Project, located east of Cascade and McCall. ICL and our partners have identified numerous concerns with the mining project, including unacceptable impacts to fisheries, wildlife, and water quality, to name a few. One topic that doesn’t garner as much attention as the impacts to Idaho’s natural resources, but is just as critical, is transportation and how all the materials and staffing necessary to implement this massive mine proposal will arrive at and depart from the very remote mine site deep in the heart of Idaho’s central mountains.

The SDEIS analyzes the impacts of the proposed mine through three alternatives:  No Action, the Johnson Creek Route, and the 2021 Modified Mine Plan (MMP) – which the Forest Service has identified as the preferred alternative. The sole difference between the two action alternatives lies in the mine’s access and transportation route. Beginning at the intersection of State Highway 55 and Warm Lake Road, both the Johnson Creek Route and the 2021 MMP would use Warm Lake Road to the approximate Landmark area.  Under the Johnson Creek alternative, mine traffic would then use the Johnson Creek Road to the Yellow Pine-Stibnite Road and on to the mine site. Under the 2021 MMP, mine-associated traffic would travel to the Landmark area, then proceed to the mine via the Burnt Log Road. This alternative requires upgrades to the existing Burnt Log Road and the construction of 15 miles of new road through Inventoried Roadless Areas and adjacent to the Frank Church River of No Return Wilderness to create the Burntlog Route.

According to the SDEIS, during construction mine traffic would use the Johnson Creek Road under both alternatives and would generate an estimated annual average daily traffic (AADT) of 65 vehicles consisting of 45 heavy vehicles and 20 light vehicles (SDEIS p. ES-22).  The construction traffic would double and triple the traffic volume on the Johnson Creek and Stibnite Roads, respectively.  Under the 2021 MMP, the upgraded Burnt Log Road and the newly constructed Burntlog Route, “would experience an increase in traffic of over 71 percent…with 27.5 percent of the traffic comprised of heavy vehicles,” (SDEIS, p. ES-23). The increased traffic will result in direct wildlife impacts (including vehicle/animal collisions, habitat fragmentation, and security loss), decreased solitude and quiet (key roadless and Wilderness values), increased travel times for recreationists, loss of access to public lands, and an increase in the likelihood of a severe accidents and spills involving hazardous materials. Both proposed access routes also have segments exposed to landslide/rockfalls and avalanches, raising the probability of accidents and spills even further.

A spill that took place in the Stibnite mine are in the 90s.

You may be asking yourself, “What kinds of materials are being transported on our public interstates, highways, and County and Forest roads?” Outside of the large equipment needed to construct the mine, access roads, and utility upgrades (such as updated and newly constructed transmission lines), there is a plethora of materials for transport. In total, more than 3,000 loads of hazardous materials will be transported to or from the mine every year. The SDEIS states that over 8.5 million gallons of petroleum products, 7,300 tons of ammonium nitrate (used for blasting), 100 tons of explosives, and 4,000 tons of sodium cyanide will move annually over the mine’s identified transportation routes (Table 4.7-1, p. 4-122-124). More than 46,000 tons of hazardous bulk solids would be transported to or from the mine site, and an unknown quantity of wastes containing mercury from ore-processing would be transported on a yearly basis (p. 4-124).

While the SDEIS reports no spills in the 288 trips of fuel tankers carrying 4,000 to 4,500 gallons over the last 11 years (SDEIS, p. 3-99), that is still fewer trips than needed to transport hazardous materials in and out of the mine site each month during 15 years of operations if this project was approved.

While the transportation analysis for this proposed mega-mine focuses solely on transportation routes originating from Cascade, the small mountain town and agricultural community is hardly the hub for chemical manufacturing and storage.  However, transportation routes beyond the intersection of Highway 55 and Warm Lake Road were not identified and included in the SDEIS analysis – so the risks to other communities along those unidentified routes remain unknown. The Forest Service based this myopically focused analysis on research concluding that most spills occur on backcountry roads, but many Valley County residents are also concerned about sharing interstates, highways, town streets, AND backcountry roads with all that mining traffic and the inherent risk of potential spills.

While it’s entirely true that not all roads have the same level of safety, and that spill risks per mile are likely going to be much higher on the roads from Cascade to the mine site than the roads from the various endpoints and Cascade, the number of and probability of accidents should not just be looked at on a per mile basis – it should be based on the total number of miles the hazardous materials would be transported.

Stibnite mine. Ecoflight photo.

So what are the chances of a vehicle accident and potential resulting hazardous materials spill? When looking at the expected number of releases of hazardous materials, the release rate per mile traveled by a truck carrying hazardous materials, and the total number of miles traveled by those trucks – the probability of at least one accident is over 96%.

When estimating the number of accidents involving hazardous material vehicles (with and without spills), this method shows we can expect 4.2 accidents involving a truck carrying hazardous materials during the Stibnite Gold Project. 

This probability model is pretty standard. It has precedent of being used in other mining Environmental Impact Statements and is based on the common knowledge that the more miles something travels, the higher probability that it will get in an accident. This is the method ICL and our partners used to predict the changes of a hazardous materials spill. The SDEIS fails to quantify spill estimates using this or any other model.

In reality, the risk of accidents or spills is much greater than we lay out here. Using the equation provided, we only look at 70 miles of the known transportation route.  A complete analysis would be all encompassing miles and include the entire transportation route from source to destination. Sadly, the Stibnite Gold Project SDEIS fails to adequately examine the potential risks and full impacts of mine-related transportation, not only to Valley County residents but to all Idahoans.

Our review of the Stibnite Gold Project’s SDEIS shows that, if implemented, the project would have numerous impacts on Idahoans and our state’s natural resources, many of which cannot be mitigated or lessened, and several, including the full impacts related to the transportation system, remain unknown. The best protection against adverse effects associated with the proposal is to protect the South Fork Salmon River, its tributaries, and the surrounding rivers and lands which support a plethora of wildlife and provide solitude and ruggedness that so many Idahoans seek while recreating.  

Speak up for this incredible piece of Idaho and our West Central mountains and rivers, by submitting comments by Jan. 10 to the Forest Service, voicing your concerns regarding the Stibnite Gold Project. 

For more information on writing comments, check out our first blog of the Stop Stibnite series here, or sign up for alerts on how you can help protect the South Fork Salmon River watershed.