Context for Gold King Spill Peter Butler, Ph.D. Animas River Stakeholders Group Dec. 15, 2016

Gold King

Upper Animas Mining Mining begins in 1870’s. Mining heyday, early 1900’s, possibly 200 mines in existence. After World War II, very few mines operated, although some that did were quite sizable. The last and largest mine in the Basin, the Sunnyside, closed in 1991.

Gold King Mine Mining begins in earnest at the Gold King Mine in the late 1890’s. Production ends at the Gold King Mine in the 1920’s. At the time, one of the biggest mines in the area. Some exploration in the 1980’s and early 1990’s. The entrance collapsed in the late 1990’s

Gold King Level #7, circa 1906

Gold King Level #7 after the spill

Gold King #7 Dump North Fork Cement Crk

Water Quality in the Animas Early explorers noted the natural stream degradation in mineralized creeks. Water quality problems in the Animas River related to mining have been recognized for over hundred years. Use of tailings ponds began in the mid-1930’s. First water treatment of mine drainage began in the late 1970’s. Comprehensive water quality improvement efforts began in 1994 with the formation of the Animas River Stakeholders Group (ARSG).

ARSG Approach Initiated by CDPHE in 1994, ARSG is not a formal entity. Anyone can be a stakeholder and participate. Make decisions by informal consensus. Don’t try to assign blame. Don’t get involved in permitted sites.

ARSG Watershed Approach Characterize abandoned and inactive mine sites (~175 draining mines and ~180 mine waste piles sampled; about 15% of the sites contribute 90% of the loading, pre- Gladstone issues). Determine feasibility of remediation of sites and prioritize sites to address. Propose water quality standards based on remediation feasibility (in 2001). Never all attained. Remediate sites.

Koehler Tunnel Before After

Bullion King Remediation

NPS 319 Infiltration Control Project Carbon Lakes Ditch (2003) Mine Workings Below Ditch San Antonio Mine Dump

Carbon Lakes Trans-basin ditch Before After

Koehler Bulkhead

Remediation Over 60 mine remediation projects have been completed in the Animas Basin. (About ½ by mining companies, ¼ by Federal agencies, ¼ by ARSG) Most of the mine waste sites have been completed. Only about 5 draining mines have been addressed. Liability Concerns – Lack of Good Samaritan Provision, Funding and Long-Term Maintenance .

Results Up to a 70% reduction in zinc and copper in Mineral Creek. Brook trout recently found in Upper Mineral Creek. Measureable improvements in the Animas above Silverton. Newly found trout near the headwaters. By early 2000’s, much improved fishery downstream of Silverton. However, by mid 2000’s previously permitted sites became much bigger metal contributors that significantly worsened water quality.

Discharges Around Gladstone In 1990’s: Sunnyside Gold treated 1600 gpm from American Tunnel. Before Gold King release: about 600-700 gpm untreated from four portals – as much metals as all other draining mines combined.

Impacts of the Gold King Release Physical Release: 3 million gallons released, 880,000 pounds of metals. (EPA: 5.4 MGD from ~40 sites, ~ 3,000 lb/d) Economic: In Colorado, substantial for a couple of months, minimal after that (except governmental). Political: Dropped opposition to Superfund designation (48 sites designated), flurry of bills introduced in Congress, increased identification and characterization of problem mine sites by state agencies.

Impacts of the Gold King Release Legal: State of New Mexico and the Navajo Nation have filed lawsuits against EPA, State of Colorado, Sunnyside Gold Corp. and other small mining companies. Human Health: So far, no problems identified. Wells sampled. Fish tissue sampled. Ecological: Minimal Impacts. No demonstrated impacts on fish and macroinvertebrates. Animas meets all aquatic life standards in Durango. Sediments are biggest concern.