Case Summary: EPA Issues Order for Groundwater Investigation at Bonita Peak Mining District Superfund Site

On March 15, 2018 EPA issued a unilateral administrative order to Sunnyside Gold Corporation to conduct groundwater investigation activities at the Sunnyside Mine and surrounding area in the Bonita Peak Mining District Superfund Site in San Juan County, Colorado. Sunnyside Gold is a current owner and past operator of the Sunnyside Mine.

EPA issued the order to Sunnyside Gold to conduct a remedial investigation at a portion of the site so the Agency can identify surface water impacts from the groundwater system, evaluate potential cleanup options, and assess the condition of existing bulkheads. EPA’s order requires this work to begin in 2018, with some identified items being completed by the end of the year. The company has an opportunity to request a conference with EPA to discuss the order before it becomes effective.

Bottom-dwelling organisms, such as mayflies, stoneflies, or caddisflies, have been measurably impaired in approximately 30 miles of the Animas River due to natural and mining-related heavy metals concentrations in surface water. In addition, toxic metals concentrations in the Animas River below Cement Creek have eliminated virtually all fish down to Elk Creek (6 miles downstream) and all cutthroat and rainbow trout down to Cascade Creek (19 miles downstream), where only a small community of brook trout and brown trout exist. Due to natural processes, it is unlikely that Cement Creek ever supported fish communities; however, mining-related metals contamination in Cement Creek is a major source of contamination in the Animas River. The investigation ordered by EPA will help the agency form an approach to combatting these impacts on the Animas River’s ecosystem.

On this page:

• Information about Sunnyside Gold Corporation
• Information about the Bonita Peak Mining District Superfund Site
• Summary of the Unilateral Administrative Order
• Contact Information

Information about Sunnyside Gold Corporation

Sunnyside Gold Corporation is incorporated in Delaware and authorized to do business in Colorado.  Sunnyside Gold Corporation is the present owner of mining claims in the area of investigation, and previously operated the Sunnyside Mine, the largest mine in the investigation area.

Information about the Bonita Peak Mining District Superfund Site

Mining at the Bonita Peak Mining District Superfund Site began in the 1870’s and the last significant mine to operate at the Site, the Sunnyside Mine, closed in 1991. The Sunnyside Mine was the largest and most productive mining operation in the Bonita Peak Mining District. The Sunnyside Mine is situated at the headwaters of the Eureka Gulch in the area of the historic Lake Emma at an elevation of approximately 12,320 feet. Sunnyside Gold Corporation operated the Sunnyside Mine from 1985 to 1991 and acquired ownership of the Sunnyside Mine in 1992.

Surface water sampling data from the investigation area have shown elevated concentrations of heavy metals, including beryllium, cadmium, copper, lead, manganese, silver, and zinc.  The mining influenced water flowing from the mine portals in the investigation area has been measured to be as high as 1,500,000 gallons a day. 

Additional information is available on the Bonita Peak Mining District Superfund site profile page.

Summary of the Unilateral Administrative Order

The scope of the Unilateral Administrative Order involves assessing and developing the ability to monitor bulkheads present in the area, understanding the contaminants present in ground water, and determining potential underground connections between the Sunnyside Mine and other mines, tunnels, ground water, and surface water.

Contact Information

For more information contact

Richard Sisk
Enforcement Attorney
U.S. Environmental Protection Agency
Region 8
1595 Wynkoop Street
Denver, CO  80202-1129
Mailcode 8ENF-L
(303) 312-6638
Sisk.richard@epa.gov

Douglas Naftz
Enforcement Attorney
U.S. Environmental Protection Agency
Region 8
1595 Wynkoop Street
Denver, CO  80202-1129
Mailcode 8ENF-L
(303) 312-6942
Naftz.douglas@epa.gov

Nicholas Sciretta
Attorney-Advisor
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, D.C. 20460
(202) 564-7416
Sciretta.nicholas@epa.gov