Engineering Evaluation/Cost Analysis (EE/CA) Study at Coggins Flat
The National Park Service is seeking public review and comment on a Draft
Engineering Evaluation/Cost Analysis (EE/CA) that considers removal action
alternatives for the Coggins Flat Area Placer Mine (Site) located within Whiskeytown
National Recreation Area (WHIS), Shasta County, California under the Comprehensive
Environmental Response, Compensation and Liabilities Act (CERCLA).
In 2006, a Preliminary Assessment concluded that a release of mercury to soil and
surface water had likely occurred from historical Site mining activities. Subsequent
investigations showed mercury concentrations in soil exceeding applicable screening
criteria, and recommended an EE/CA for further characterization of mercury
contamination and the selection of a Non-Time-Critical Removal Action (NTCRA)
alternative if deemed necessary.
The EE/CA identifies removal action objectives for protection of human health and the
environment, develops removal action alternatives, and assesses the effectiveness,
operational feasibility, and cost of the alternatives. Accordingly, the NPS has
determined that the use of removal action authority to investigate, abate, prevent,
minimize, stabilize, mitigate, and/or eliminate the release or threat of release of
hazardous substances at or from the Site may be appropriate.
You may review and comment on the document by clicking on the 'Open for Comment' link on the left.
Gary Riley, (206) 220-4040