Nightmares of Cyanide
By Tom Hallberg, Idaho Conservation Organizer at Greater Yellowstone Coalition
To reach tiny flakes of gold hidden in tons of rock, modern mining companies strip entire hillsides, crush them into dust, spray them with a cyanide solution, and store everything in giant lined pits. The chemical reacts with the gold, pulling it from the rock and allowing the metal to be processed. No other processing method has proven to be economically viable with the low-grade ore left on the planet.
The storage and tailings ponds can be hundreds of acres, and keeping cyanide in them leads to environmental problems, from leaky liners contaminating soil and groundwater to animals finding their way into the toxic water. Some spills are small and cleaned up quickly, contaminating a few dozen acres of soil that can be mitigated, but tailing pond failures and other catastrophes often result in unfixable environmental damage. These are the stories of the worst that have happened at American mines in recent decades. Allowing open-pit, heap-leach, cyanide mining at in the Centennial Mountains above Kilgore, Idaho could lead to these same types of catastrophes.
Zortman-Landusky, Montana
A Fort Belknap resident holds a glass of water contaminated by toxic mining waste. (Credit Earthworks)
Set in craggy, spire-filled mountains on northern Montana’s Fort Belknap Indian Reservation, the Zortman-Landusky Mine complex operated from 1979 to 1998, pulling gold and silver from connected open-pit, heap-leach, cyanide mines. A dozen cyanide solution spills came from the complex, with the largest, a 52,000-gallon catastrophe in 1982, polluting the aquifer and poisoning drinking water for the historic town of Zortman in the headwaters of the Missouri River. Owner Pegasus Gold declared bankruptcy in 1998, and the $46.5 million it posted in reclamation and water bonds failed to cover the $77 million that has been spent on the cleanup, leaving taxpayers to cover the difference. More than 25 years after Pegasus Gold stripped the gold from the hills, pollutants continue to leach into ground- and surface water, harming ecological and Tribal cultural resources. Zortman-Landusky’s deleterious effect on the Fort Belknap Reservation and the Missouri River watershed made it the catalyst for Montana’s statewide ban on cyanide use in mining.
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Summitville, Colorado
A sign outside the Summitville Mine warns of hazardous materials. (Credit Anne Landman)
In 1991, residents of southern Colorado noticed dead fish floating belly up in the Wightman Fork and the Alamosa River downstream of the Summitville Gold Mine on the ancestral lands of the Southern Ute Tribe. Historic claims were spent, but a subsidiary of Canadian company Galactic Resources had been using open-pit, heap-leach, cyanide mining practices to pull gold from the remaining lower-grade ore. Heavy metals, acid mine drainage, and tailing pond leaks leached into the watershed, with fish die-offs and water quality issues found up to 17 miles downstream. Galactic filed for bankruptcy in 1992; since then, federal and state governments have paid more than $250 million to clean up the Superfund site. More than 30 years after the mine’s closure, state taxpayers pay $2 million annually to treat thousands of gallons of polluted water that spill from the once-pristine hillsides.
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Colorado Department of Public Health
Paradise Peak, Nevada
Satellite imagery of the Paradise Peak Mine near the Gabbs Ranger Wilderness Study Area. (Credit Google Maps)
In the shadow of Nevada’s Paradise Range on the ancestral lands of the Northern Paiute Tribe, just 13 miles from the Gabbs Valley Range Wilderness Study Area, the Paradise Peak Mine was an open-pit, heap-leach, cyanide gold mine that operated from 1986 to 1994. Populated by sparse, yet hardy grasses and sagebrush, the arid desert between Nevada’s classic basin and range formations holds the scars of a mine that has been defunct for nearly 30 years—outbuildings, a vast circular pit, and a teardrop-shaped tailing pond. In the late 1980s, migratory birds died in a series of incidents on that 23-acre pond, including ducks, pelicans, gulls and great horned owls. State officials had allowed operators FMC Gold Corporation and Armetico Incorporated to dump such high cyanide levels in the pond because wildlife administrators did not believe migratory birds would use the remote section of central Nevada. In all, roughly 1,300 birds died before mine operators took corrective action.
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DeLamar Mine, Idaho
Heavy machinery dig the open-pit DeLamar Mine in southwest Idaho. (Credit Integra Resources)
In 1990 and 1991, several groups of migratory waterfowl passed over the DeLamar open-pit, heap-leach, cyanide mine and its 120-acre tailing pond in Idaho’s Owyhee Mountains. More than 100 birds died after landing on the cyanide-laced open water. The U.S. Attorney’s Office charged owner Kinross Gold Corporation with six misdemeanors for violating the Migratory Bird Treaty Act, and the company had to haze migratory birds until it could detoxify the pond, a process that took more than a year. Kinross closed the mine in 1998 due to low gold prices, but in 2017, foreign-owned Integra Resources bought it, saying higher gold prices warranted reopening Delamar and planning to again use open-pit, heap-leach, cyanide techniques to extract the remaining gold.
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1991 Statesman Journal PDF
Homestake Mine, South Dakota
The Homestake Mine’s open pit is just off the road in Lead, South Dakota. (Credit Wikicommons)
More than a century of gold mining happened at Homestake Mine in the Black Hills, the ancestral homelands of the Lakota Tribes. Miners dug into mountains until the pit reached 8,000 feet deep, creating the second-most productive gold mining area in the United States. Decades of dumping toxic chemicals into Whitewood Creek created a gray sludge in the water and killed most, if not all, aquatic insects and fish. Locals called it “Cyanide Creek.” The EPA found in 1971 that the Homestake Mining Company was dumping 312 pounds of cyanide into surrounding waterways each day, along with heavy metals and suspended solids. Whitewood Creek was named a Superfund site in 1984, and it took 12 years to clean it up enough for the EPA to delist the area. However, following the delisting, six to seven tons of cyanide-contaminated tailings spilled from Homestake into the waterway on May 29, 1998, killing fish and setting the ecosystem back years. Cleanup efforts continue to cost small, nearby towns like Deadwood hundreds of thousands of dollars annually.
Charles Washington Merrill introduced cyanidation techniques at Homestake in the early 1900s, earning him the nickname “Cyanide Charlie,” squeezing value out of low-grade ore and paving the way for modern open-pit, heap-leach cyanide mining.
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Wharf Mine, South Dakota
Danger signs warn of cyanide outside of a mine. (Credit Earthworks)
Near the Homestake Mine sits the only working, large-scale gold mine in the Black Hills. The Wharf Mine, an open-pit, heap-leach, cyanide operation, covers nearly 8,000 acres on the homelands of the Lakota tribes. In 2023, the U.S. Forest Service and South Dakota’s Board of Minerals and Environment approved an expansion that will extend the Wharf Mine’s life another one to three years, despite rampant spills and pollution. In 30 years of operation, 216 “accidental spills” have been reported at the mine, an average of 5.4 toxic leaks each year. After such events, Chicago-based owner Coeur Mining Company often incorrectly filled out required paperwork, failing to report the volume of toxic materials spilled. Levels of selenium and other pollutants, including nitrates, ammonia, coliforms, and cyanide, in False Bottom Creek on the site have consistently tested above EPA requirements. Reports show heavy metals contamination dating back at least to 2014, but state officials only recently required Coeur to address the problem, meaning a decade of contamination has gone unchecked.
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At many of these sites, cleanup and expensive monitoring will continue forever. Mining companies are required to post reclamation bonds in case a spill happens, but the amounts rarely cover cleanup costs. Instead of the companies, taxpayers are forced to pay instead, while impacts on wildlife and water quality persist for decades. Kilgore’s location in the headwaters of the Eastern Snake Plain Aquifer means contamination from cyanide could impact hundreds of thousands of Idahoans and the state’s thriving agricultural and recreation economies.
Consider joining our list of advocates to help keep Kilgore from being the next place destroyed by open-pit, heap-leach, cyanide gold mining.