Hazel Creek Mining Site Assessment and Remediation

Project Profile
Location: El Dorado County, California
Owner: Private Lumber Company
Total Project Value: $750,000
Consultant/Engr. Cost: $50,000
Square Footage/Area: Approx 100 acres
Completion Date: 1999-2009

The Hazel Creek Mine is an historic gold mine in El Dorado County, California. The mine was last active in the early 1980s, and then abandoned, leaving several ponds of mine tailings and open mine workings. The property owner was issued a Cleanup and Abatement Order by the California Regional Water Quality Control Board (CRWQCB). Stratus personnel were requested to assess waste and complete the cleanup and closure of the site.

Project Challenges:
The site assessment determined that the tailings were Group B mining wastes under Title 27 of the California Code of Regulations, because the wastes were acid generating. Lead in the tailings was the chemical of concern at this site. The mine tailings were a threat to water quality because of the acid-generating characteristic and because some of the tailings were located within a flood plain.

Stratus Solutions:
The mine tailings were consolidated into a Waste Management Unit (WMU) on the site away from the flood plain. To ameliorate the acid-generating characteristic a neutralizing agent, in this case limestone from a local quarry was crushed and blended with the mine tailings. This material was capped with 1-foot of compacted soil overlain by a one-foot vegetative layer using material native to the site, and seeded with endemic grass species. Since its construction in 1998, the WMU has been monitored and reported by the client and Stratus personnel through Waste Discharge Requirements issued by the CRWQCB. No water quality impacts have been detected at the site since the WMU construction.

Crushed limestone was blended with the mine tailings to ameliorate acid-generating characteristics