It’s a beautiful, 60-degree day, the sky a cloudless blue. Spunn Road is lined by stately houses looking down on the historic main street of Jackson, California, the high peaks of the Sierra Nevada mountains visible in the distance. There’s a slight bend in the road—and there it is. A chain-link fence topped with barbed wired blocks access to a few dilapidated buildings and a 50-foot-tall rusting steel structure that, in another life, hoisted rock from the depths below. There’s a sign on the fence: TOXIC HAZARD KEEP OUT.
Argonaut Mine is located in the middle of the literal Mother Lode at the heart of California’s Gold Country region. It operated on and off from the 1850s until World War II. After that, the mine sat largely vacant as the town of Jackson grew around it. Today, the only obvious remains are the buildings and, visible across the valley, the remnants of the neighboring Kennedy Mine, which just beat out Argonaut for the title of the deepest mine in the state.
At Kennedy, the miners constructed an elaborate series of multi-story wooden wheels one can still visit today to lift the mine waste, called tailings, and dump it in the valley below. At Argonaut, they dumped the waste—full of arsenic, lead, and other heavy metals brought up from underground, as well as cyanide and mercury the miners added to help extract the gold—a few blocks away.
From the road, all that’s visible of the tailings area today is a large, muddy vacant lot, marked by no more than a small sign on a flimsy-looking fence. One can see where part of the fence was replaced last year after a drunk kid plowed through it.
But the brown muck here is acidic and has average levels of arsenic, an element that can cause cancer, diabetes, cardiovascular disease, and skin lesions, of 400 parts per million. The level at which the state requires a site to be cleaned up is 100 parts per million. John Hillenbrand, a geologist with the Environmental Protection Agency, says he once recorded a value of 90,000 parts per million. Mercury and lead levels are also well above acceptable values.
At the bottom of the mining site, there’s also an old, four-story tall concrete dam, built in 1916 to prevent waste from the mine from flowing downstream. In 2015, the US Army Corps of Engineers declared the mine structurally unsound. If it failed, the agency said, it would send a 15-foot-deep mudflow past Jackson Junior High School, built directly below the dam, and into town. Within a year, Argonaut was listed on the National Priorities List, the list of so-called Superfund sites that are among the most contaminated places in the country.
Despite the cleanup at Argonaut being in the early stages, and the site being, as Hillenbrand describes it, “more straightforward” than most Superfund sites, the agency has already spent $8 million over the last several years. He says they have at least $14 million more to go.
And Argonaut is just one of thousands of abandoned mines littered across Gold Country.