US Forest Service, Mining Mill Sites, CO

The USDA Forest Service (USFS) has been working with the Colorado Geologic Survey to identify abandoned mine sites in the state of Colorado. In 2004, two sites were identified along Halfmoon Creek, southwest of the town of Leadville: the Champion Mill and the Halfmoon Creek Mill. At the request of the USFS, SUMMIT conducted CERCLA Preliminary Assessments/Site Inspections ((PA/SIs) for the sites.

The scope of services included:

• Preparing and reviewing documentation related to environmental statutes
• Characterizing contaminated sites and waste streams
• Performing risk assessments
• Providing health and safety support

A reconnaissance visit was first conducted to visually characterize the location of wastes and local hydrology, and identify the presence of any sensitive environments and nearby population centers. Sampling locations and site features were georeferenced using Global Positioning  System (GPS) equipment, and waste volumes at both sites were estimated. A Potentially Responsible Party (PRP) search was then conducted to establish evidence of liability for waste at the sites. The search required researching federal, state and, local records to obtain and review aerial photographs, maps, licenses, permits, studies, and property titles. PA/SI reports were prepared that provided the site history, physical setting, site features, proximity to groundwater and surface water, potential human and ecological receptors, identification of potential contaminants, and recommendations for further action.