Case Study as part of a Web-based
Technical and Regulatory Guidance
Black Butte Mercury Mine
Lane County, Oregon
1. Site Information
1.1 Contacts
Bryn Thoms, Project Manager
DEQ Western Region Cleanup Program
1102 Lincoln Street, Suite 210
Eugene, OR 97401
Telephone: 541-687-7424
E-mail: [email protected]
1.2 Name, Location, and Description
The Black Butte Mine is located on the northeast flank of Black Butte in
southern Lane County, approximately 10 miles south of Cottage Grove, Oregon.
The 300,000–cubic yard tailings pile fronts Dennis Creek, which flows into
the Coast Fork Willamette River and the Cottage Grove Reservoir. Site features
include several tailings piles, a former mill structure with a rotary kiln,
several dilapidated buildings, an unimproved road system, and partially caved-in
mine adits.
2. Remedial Action and Technologies
The Removal Action was conducted in 2007 as an interim action to stop the
migration of contaminated tailings into Furnace Creek. Tailings with higher
levels of mercury were excavated and placed into an on-site repository which
was capped with tailings containing lower concentrations of mercury. Tailings
on the banks of Furnace Creek were excavated and used for capping of more
highly contaminated areas. The slopes of the creek banks were regraded to
slow erosion of tailings into the creek.
3. Performance
Three different action levels were set to guide the excavation (Table 3-1).
For the area of the Old Ore Furnace, the Environmental Protection Agency
(EPA) Region 9 Preliminary Remediation Goal of 23 mg/kg for mercury in soil
in a residential scenario was used. This value is protective of mercuric
chloride for the dermal contact exposure pathway. Oregon Department of Environmental
Quality (DEQ) calculated a cleanup value for mercuric sulfide, as opposed
to mercuric chloride, protective of the dermal contact pathway in a residential
scenario, and determined 115 mg/kg would be an appropriate action level at
the New Furnace area, regarding the slopes of the Main Tailings Pile and
the cover material taken from the Main Tailings Pile. Selective sequential
extraction analysis results had shown that the mercury in these areas was
tightly bound as mercury sulfide. For areas where the tailings could potentially
flood or erode into a creek, an action level was calculated by determining
a background concentration and multiplying that value by 3.
Table 3-1. Cleanup concentrations
Contaminant |
Cleanup Concentration (mg/kg) |
| Mercury (tailings) | 23 |
| Mercury (tailings on creek banks) | 10 |
| Mercury Sulfide (cinnabar) | 115 |
4. Costs
Costs of activities at this site are reported as a total for the entire removal
action project and include EPA (direct and indirect), U.S. Coast Guard, and
contractor costs.
- Capital: $472,148
Cost can also be broken down by cubic yard of tailings treated:
- Capital: $17.70/cubic yard
- Operation and maintenance: $0.50/cubic yard per year for 10 years
5. Regulatory Challenges
No regulatory challenges were encountered during the Removal Action. There
was good coordination between EPA and DEQ. As a final remedy, it will require
a deed restriction restricting use and restricting certain construction activities
to maintain the repository and the slopes/vegetation. This remedial action
is currently considered an interim removal. Additional contamination was
found to be present during the removal action which will need to be addressed
at a later date. The Black Butte Mine is scheduled to be proposed for the
National Priorities List in fall 2009.
6. Stakeholder Challenges
ODEQ conducted community relations activities including the distribution
of a fact sheet and the creation and maintenance of a website where updates
of the cleanup were listed.
7. Other Challenges and Lessons
Learned
No information available.
8. References
U.S. Environmental Protection Agency. 2008. Final Removal Action Report
of Black Butte Mine. www.deq.state.or.us/Webdocs/Forms/Output/FPController.ashx?SourceId=1657&SourceIdType=11.
