Tomales Bay, Marin County California

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MERCURY MADNESS
REMEDIATION OF THE GAMBONINI MERCURY MINE
Tomales Bay, Marin County California
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LOCATION GEOLOGIC MAP
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Tomales Bay Oyster Farm
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Walker Creek Estuary on Tomales Bay
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Gambonini Mercury Mine 1997

Open pit mine area

Old ore separation building.
Tailings dump showing erosion. and slip scarp.
Gambonini Creek is on lower righ side.
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MERCURY FLUX DATA

• Based on stream turbidity and discharge
  measurements.
• Data taken at onelocation over 59 days only
  at peak rainfall periods.
• Estimates mercury content based on total
  suspended solids (TSS)
• Does not consider outside influences
  (upstream mines)

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Remediation Alternatives for the Gambonini
Mercury Mine.
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1998-99 mine site restoration phases.
1997, Before starting remediation work
1998 After grading and
buttress construction. Photos courtesy of Cotton,
Shires Associates.

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Post Remediation Photo
Post remediation photo taken Sept. 1999. The
reconstructed stream channel is obscured by
vegetation but lies along the right hand side of
the graded slope. (Smelser, Whyte 2001)
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MANAGEMENT ISSUES

• Creeping Requirements.
• Failure to listen to local community
• State laws focus on environmental QUALITY.
  Federal on POLICY
• Large number of agencies involved. No central
  authority.
• Insufficient funding resources available
  during most of project life.
• Myriad of permits required and conflicting
  requirements.
• Fear of potential liability issues working on
  private property.
• Making of decisions based on potentially
  flawed data.
• No independent review process in decision
  making and planning.
• Failure to utilize local resources and labor
  during project.

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Remediation Project Management Planning.
Problem Identification Problem
characterization Expert witnesses Development of
preliminary remediation alternatives Superfund
classification Project planning and setting of
goals Feasibility studies Design level
engineering geology investigations Final Plan and
peer review/approval Project Construction As-built
reports Erosion control and revegetation Post-pro
ject monitoring
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RECOMMENDATIONS

• Site management process should be determined
  early in project.
• Lead agency and/or emergency management team
  defined at start.
• Define which and whose requirements and
  regulations are to be met.
• Understand site and surrounding environment.
• Preliminary plan and milestones defined early.
• Develop realistic estimate of resources required
  to perform project.
• Responsibility for milestones assigned.
• Independent review process defined and followed.
• Involvement of local community representatives
  throughout project.
• Define and provide resources for continued work
  and monitoring A/R.

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Mine area from other side of hill. Only portion
of mine still visible in this photo is
raw red (cinnabar) cut above old open pit at top.
Photo by Kathryn Ketman, 2004.