Since the early 1900s, the Stibnite mine site, located high in the mountains of central Idaho and within the Nez Perce Tribe’s aboriginal territory, has been heavily impacted by mineral exploration activities, including mining, ore heap leaching and spent ore disposal, smelting, and the disposal of mine tailings. These activities have resulted in toxic metals polluting important headwater streams and associated seeps that exist on the historical mine site, as well as the East Fork South Fork Salmon River, which flows through the site. Mining activity ceased at the site in the 1990s, after the decommissioning of Hecla Mining Company’s heap leach pad, and the long process of ecological recovery began, aided by millions of dollars in cleanup actions at the site by the Environmental Protection Agency and Idaho Department of Environment Quality. In 2009, a sharp reversal came at the mine site, however, when Perpetua Resources, a Canadian mining company, initiated mineral exploration activities as part of their proposed Stibnite Gold Project.
The hard rock mining industry is one of the largest sources of toxic waste in the country. Gold mining, in particular, is a significant source of toxic releases of cyanide, arsenic, mercury, cadmium and other hazardous substances to waterways. A 2017 report (Gestring & Hadder, 2017) on gold mine spills and failures reviewed data from 27 operating U.S. gold mines (representing 93% of U.S. gold production) and found that 100% had experienced at least one pipeline spill or other accidental release, including spills of cyanide solution, mine tailings, diesel fuel, and ore concentrate. Seventy-four percent of those mining operations had failures resulting in water quality impacts to surface water and/or groundwater including impacts to drinking water supplies for homes and businesses, loss of fish and wildlife habitat, and fish kills. For the seven operations where water quality impacts were not reported, it was largely because there were no perennial streams present in the area and groundwater was generally very deep (>250 feet).
As easily extractible gold becomes scarcer, the ratio of rock to gold becomes greater. For one ounce of gold, miners could extract 20 tons of rock. At the Stibnite Mine site, Perpetua Resources proposes to extract gold from the remaining low-grade ores found there using the process of cyanidation (cyanide leaching), which will generate a huge volume of mine waste that will become a permanent feature on this landscape. Midas Gold proposes to literally fill in valley bottoms and the streams that flow through them with millions of tons of waste rock. The scars of this destructive process will remain long after Midas Gold has extracted their riches from the land, and treatment of the toxic waste associated with this project will likely be needed in perpetuity.
The East Fork South Fork Salmon River and its tributaries are important spawning streams for Chinook salmon, which the Nez Perce Tribe has a treaty-reserved right to harvest. Toxic pollutants generated by this project will directly, and negatively, affect the aquatic life in these streams and the people who use them.
Gestring, B., & Hadder, J. (2017). U.S. Gold Mines Spills & Failures Report. Washington, DC: Earthworks.
Marshall, A. G. (2006). Fish, Water, and Nez Perce Life. Idaho Law Review, 763-793.