Threats to the Salmon River – Stibnite Mine

March 18, 2026 3:05 am

The Salmon River has been special to me ever since my first trip down it in 2013. There is something magical about every single run I’ve taken down it. I’ve always felt compelled to help protect it- it’s one of the main reasons I love river guiding. I feel like when we are able to share the river with others they often become stewards and guardians of it. But on this trip I felt both an urgency and an outrage about the river that I had never felt so strongly before.

While there are lots of threats to the river, the one that I have thought about the most since our trip is the Stibnite Gold Mine (SGM) project on the South Fork of the Salmon River. The SGM is an open-pit gold, silver, and antimony mine along with an ore-processing facility. Perpetua Resources, the gold mining company behind this project, says that this project will provide antimony to the U.S. military. While antimony is a key mineral for a range of military products, Perpetua Resources themselves have admitted that only around 10% of the antimony mined at the SGM will be headed to the military due to the lower grade antimony present at the site. Other mining projects in the western U.S. contain higher grade antimony that the military can more easily use.

In many ways, the presence of antimony at the SGM site is what is allowing Perpetua Resources to push forward with its main goal: mining gold. Jon Cherry, the CEO of Perpetua Resources, recently said on the podcast Mining Stock Daily that “Antimony is the enabler because of the government’s support. The economics are driven all by the gold. Our mine plan is based on gold.” While I do think that lots of people could be convinced that the mining of antimony is important for national security, it’s hard to imagine many people being willing to permanently damage public land and water so that investors in a gold mining company to get rich. To add insult to injury, the Mining Law of 1872 (yup, we still use that) exempts companies from paying royalties on gold mined from public lands. So while the government receives a some money when things such as oil and gas are mined on public lands, there would be no royalties on the predicted $18 billion of gold that would come out of the ground.

In the best case scenario, the SGM would wreak havoc on public lands, waters, and health. The proposed project would destroy over 20% of critical habitat for threatened chinook salmon and bull trout in the project area. The water temperature is also projected to rise to lethal levels for these fish. The project also violates Indigenous treaty rights and would permanently scar thousands of acres of public land in the headwaters of the South Fork of the Salmon River. Contamination of the water from arsenic, mercury and other heavy metals would also likely occur.

In a worst case scenario with a spill, water contaminated with cyanide and other pollutants would flow downriver, onto the Main Salmon, Snake, and Columbia Rivers. The risk of a spill in open-pit cyanide leach mining is so real that the practice has been banned in neighboring Montana since 1998.

In the end, river conservation isn’t something that we will someday just achieve. These special places will likely need us to keep advocating for them in perpetuity. And while we definitely need mines here in the U.S., it doesn’t mean that every mine is the right mine. While the public comment period for the Stibnite Gold Mine project is currently closed, there are lots of organizations continuing to work to stop this project through other methods. The list below is in no way exhaustive- these are just some of the organizations that I know that are working on this project. If you feel passionate about the Salmon River, please consider donating to one of these organizations so that they can continue fighting to protect this place that we love.

Idaho Conservation League

Idaho Rivers United

Save the South Fork Salmon