A VOLUNTARY CLEANUP PROGRAM AT THE BONANZA MINING DISTRICT

• Jurisdiction: United States

Cleaning up the Public Domain: The Next Frontier
(Mar 1996)
CHAPTER 5B
A VOLUNTARY CLEANUP PROGRAM AT THE BONANZA MINING DISTRICT
Margaret W. Staub
ASARCO Incorporated
Denver, Colorado

The Bonanza Mining District (District) is located at the north-eastern edge of the San Juan Mountain Range of southern Colorado, roughly fourteen miles west of the town of Villa Grove. Gold, silver, lead, and zinc were discovered in Bonanza in 1880. Mining activities continued sporadically in the area until the late 1960's with heavy mining occurring during the 1920's. The Depression caused the shutdown of most mining activities in the District, however, minor amounts of exploration, rehabilitation, and mining occurred between 1930 and 1960. No major activities have occurred at the District since that time. The District covers roughly 2,040 acres of land and is comprised of 179 patented mining claims. The entire district is drained by the reaches of the 8,600 acre Kerber Creek watershed. The town of Bonanza and the Bonanza Mining District lie entirely within this watershed (MFG, 1994).

In 1993 the Environmental Protection Agency (EPA) and Colorado Department of Public Health and Environment (CDPHE) evaluated the Bonanza Mining District for possible listing on the National Priorities List (NPL) as a Superfund site. As part of the Preliminary Site Assessment (1992), the USDA Forest Service (USFS) sent out a request for information under Section 104(e) of the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) to companies and individuals who had historic involvement in the District. The identified environmental issues were impacts to surface water and potential impacts to groundwater, air, and soil from historic mining and milling activities.

Upon receipt of its 104(e) notice, Asarco initiated discussions with other private parties historically involved in the District and proposed a proactive, voluntary cleanup plan in place of the Superfund process. Asarco organized the private parties into what became known as the Bonanza Mining District Group (Bonanza Group) and initiated discussions with the State, EPA, and the USFS regarding this voluntary approach to address the environmental concerns in the District.

The State of Colorado agreed to enter into two agreements. One agreement was called the Statement of Roles and Responsibilities and was developed between State and the Bonanza Group and defined the roles of the individual parties involved. Second, the State and USFS entered into a Memorandum of Understanding, which defined the roles of the agencies with regards to managing cleanup actions on private and public lands. The following objectives were a result of these agreements. One, EPA agreed to postpone listing the site on the NPL providing efforts to address the environmental issues in the District proceeded. Two, long term water quality objectives were established for the drainage, which included meeting drinking water and...