High in the San Juan Mountains of Colorado, tourists in search of an old-time thrill can ride a coal-fired train to the historic mining town of Silverton, visit the 12-ton marble Christ of the Mines Shrine, and honor the local tradition of enthusiastic drinking. (“Sunday is not generally observed save by increased guzzling,” the Silverton Democrat wrote in 1884.) But outside Silverton lies another legacy of mining—one far quieter, and more treacherous, than a gold-rush saloon.
In the surrounding steep valleys, hundreds of defunct silver and gold mines pock the slopes with log-framed portals and piles of waste rock. When water flows over the exposed, mineral-laden rock in and around the mines, it dissolves zinc, cadmium, lead, and other metals. The contaminated water, sometimes becoming acidic enough to burn skin, then dumps into nearby streams. So-called acid mine drainage, most of it from abandoned boom-time relics, pollutes an estimated 12,000 miles of streams throughout the West—about 40 percent of western waterways.
Near Silverton, the problem became bad enough to galvanize landowners, miners, environmentalists, and local officials into a volunteer effort to address the drainage—work that has helped avert a federal Superfund designation and restore a gold-medal trout population downstream. With a few relatively simple and inexpensive fixes, such as concrete plugs for mine portals and artificial wetlands that absorb mine waste, the Silverton volunteers say they could further reduce the amount of acid mine drainage flowing into local rivers. “In some cases, it would be simple enough just to go up there with a shovel and redirect the water,” says William Simon, a former Berkeley ecology professor who has spent much of the past 15 years leading cleanup projects.