Gilt Edge Gold Mine, South Dakota

The Gilt Edge gold and silver mine is located near Deadwood, South Dakota at the headwaters of municipal water supplies for the northern Black Hills.

Leaking Cyanide

The Gilt Edge mine operated from 1988 - 1996. Lack of specific standards allowed torn containment liners, poor mine design, and sloppy management practices at the mine site. As a result, shortly after mining began, cyanide leaked into the groundwater and nearby Strawberry and Bear Butte Creeks.

In late 1992, the mine began generating acid mine drainage, reaching an extreme point in May 1995, when acid drainage from the mine's waste piles flowed offsite into Ruby Gulch Creek. Acid drainage left area streams unable to support a viable fish population.

Mining Company Threatens to Stop Treating Mine Waste Water

In May, 1998 the Brohm Mining Company threatened to abruptly abandon costly water treatment at the Gilt Edge Mine after the parent company, Dakota Mining, declared bankruptcy. Within 72 hours, pollution would have overtopped holding ponds and entered local streams and drinking water.

South Dakota Governor Bill Janklow went to court, seeking to force the company to continue to treat the water to acceptable levels. Although the mine did have a reclamation bond, government officials estimated that the $6 million bond would not even cover water treatment costs for one year.

Another Mining Superfund Site

In February 2000, the Governor of South Dakota requested that the site be designated a Superfund site to provide emergency response, as well as long-term remedial cleanup. The site was approved in December 2000.