![](media/image1.wmf)

Remediation Control Strategies and Cost Data for an Economic Analysis of
a Mercury Total Maximum Daily Load in California

By Alexander Wood

Open-File Report 03-284

2003

U.S. Department of the Interior

U.S. Geological Survey

# Contents

[Notation 3](#notation)

[Abstract 5](#abstract)

[I. Introduction 6](#i.-introduction)

[II. Mercury Remedial Options Summary
7](#ii.-mercury-remedial-options-summary)

[III. Historical And Future Mining Remediation Projects
11](#iii.-historical-and-future-mining-remediation-projects)

[A. Point-Source Reductions 11](#a.-point-source-reductions)

[B. Mercury Mine Sites 12](#b.-mercury-mine-sites)

[C. Proposed Mine Remediation Sites
17](#c.-proposed-mine-remediation-sites)

[IV. Mercury Reduction Programs And Techniques
21](#iv.-mercury-reduction-programs-and-techniques)

[A. Mercury Remediation Techniques and Technologies
22](#a.-mercury-remediation-techniques-and-technologies)

[B. Mercury Recycling Programs 25](#b.-mercury-recycling-programs)

[C. Mercury Reduction Programs and Studies
27](#c.-mercury-reduction-programs-and-studies)

[D. Sediment Control and Disposal 30](#d.-sediment-control-and-disposal)

[E. Ecosystem Restoration 32](#e.-ecosystem-restoration)

[V. Disclaimers On Remediation Cost Predictions
36](#v.-disclaimers-on-remediation-cost-predictions)

[VI. Remediation Process 38](#vi.-remediation-process)

[A. Factors Affecting Remediation Decisions
38](#a.-factors-affecting-remediation-decisions)

[B. Guidance to Documenting Costs for Remediation Projects
40](#b.-guidance-to-documenting-costs-for-remediation-projects)

[VII. Remediation Control Options And Strategies
40](#vii.-remediation-control-options-and-strategies)

[A. Hydraulic Mine Site Strategies
41](#a.-hydraulic-mine-site-strategies)

[B. General Remediation Control Strategies
42](#b.-general-remediation-control-strategies)

[C. Remediation Cost Strategy 44](#c.-remediation-cost-strategy)

[VIII. Conclusion 46](#viii.-conclusion)

[Appendices 47](#appendices)

[A: Estimated Cost for Final Compliance: Buena Vista Mine (after SECOR,
1999)
47](#a-estimated-cost-for-final-compliance-buena-vista-mine-after-secor-1999)

[B. Estimated Costs of Remediation Activities to Reduce Mercury in Clear
Lake
52](#b.-estimated-costs-of-remediation-activities-to-reduce-mercury-in-clear-lake)

[C. Carson River Mercury Mine Site
53](#c.-carson-river-mercury-mine-site)

[D. Management Plan Costs for Control of Mercury Methylation in the San
Francisco Bay Ecosystem
54](#d.-management-plan-costs-for-control-of-mercury-methylation-in-the-san-francisco-bay-ecosystem)

[E. Waste Pile Mine Remediation Costs
55](#e.-waste-pile-mine-remediation-costs)

[F. Unit Costs of Remedial Options for Hydraulic Mines
56](#f.-unit-costs-of-remedial-options-for-hydraulic-mines)

[References Cited 59](#references-cited)

#   {#section .unnumbered}

# Notation

AMD: Acid Mine Drainage

ATG: Applied Technology Group

BLM: Bureau of Land Management

BNL: Brookhaven National Laboratory

CBA: Cost-Benefit Analysis

CEQA: California Environmental Quality Act

CEPT: Chemically enhanced primary treatment

CWA: Clean Water Act

DOE: Department of Energy

EPA: Environmental Protection Agency

FRTR: Federal Remediation Technologies Roundtable

FS: Forager Sponge

GDP: Gross Domestic Price

HCAS: Historical Cost Analysis System

JAMA: Journal of American Medical Association

MTSS: Mercury Transportable Stabilization System

NEPA: National Environmental Policy Act

NPDES: National Pollutant Discharge Elimination System

NPL: National Priorities List

NPS: Nonpoint-Source

PCA: Porter-Cologne Water Quality Control Act

PS: Point-Source

PSM: Polar Star Mine

ROD: Record of Decision

RWQCB: Regional Water Quality Control Board

SBMM: Sulphur Bank Mercury Mine

SRCSD: Sacramento Regional County Sanitation District

SWRCB: State Water Resources Control Board

TMDL: Total Maximum Daily Load

TTLC: Total Threshold Limit Concentration

WBS: Work Breakdown Structure

WQO: Water Quality Objectives

WWTP: Wastewater treatment plant

USDA: United States Department of Agriculture

USFS: United States Forest Service

**Notation for Tables and Appendices**

  ------------------- ---------------------------------------------------
  AC                  Acre

  BV                  Bed Volume

  CF                  Cubic Foot

  CM                  Cubic Meter

  CY                  Cubic Yard

  Hg                  Mercury

  LF                  Lineal Foot

  LS                  Lump Sump

  MeHg                Methyl Mercury

  MGD                 Million gallons per day

  N/A                 Not available

  SF                  Square Foot

  SY                  Square Yard

  THg                 Total Mercury

  TMeHg               Total Methyl Mercury
  ------------------- ---------------------------------------------------

#  Abstract

Regional Water Quality Control Board staffs are given the challenging
task of developing total maximum daily loads (TMDL) for numerous
watersheds. The complexity of mercury fate and transport, speciation,
and biological consequences does not make this job easier. Applying cost
estimates for mercury remediation projects complicates the situation
even further. However, compiling information on past, current, and
proposed projects reveals some insights into general categories of types
of remediation costs. Numerous mercury technologies, reduction programs,
and remediation techniques provide a clearer vision of the types of
activities that public or private entities can do to reduce the risk of
mercury contamination and the associated costs of these activities. Gold
and mercury mine remediation, mercury reduction programs, sediment
management, and ecosystem restoration projects are all possible
solutions with certain advantages and disadvantages. Agencies have to
decide which priorities are more important when assessing a potential
remediation project, area, technique, and activity.

This report focuses on the costs that are associated with a suite of PS
and NPS remedial strategies that are applicable to mercury sources for
use as a resource in developing an economic analysis for mercury TMDLs
in California. These costs are for past, current, and proposed remedial
projects comprising of project development, environmental compliance,
permit approval, cleanup, construction, and other transaction costs. The
purpose of the report is to illustrate the general costs associated with
various remedial practices that are applicable to mercury sources in
California.

Mercury mitigation efforts could focus on two problems that mercury
imposes on the natural environment and the general human population.
These problems are the accumulation of mercury in the physical
environment, given mercury's affinity for sediment, and the
transformation of mercury in response to environmental conditions to an
organic form, methyl mercury, which can potentially cause adverse health
effects. These problems can be mitigated through mine remediation or
sediment control or disposal, as well as through ecosystem restoration
projects (although there is the possibility of adverse effects as well).

Although there are several thousand more mines in California, the
lengthy and costly endeavor of mitigating mercury contamination prevents
many projects from proceeding from the planning stages to the
implementation phases. In addition, there are litigation concerns by
many mine owners who fear being held liable for future contamination if
a site is not fully mitigated. Furthermore, very few projects have been
implemented to reduce mercury-laden sediment or to alter ecosystems
specifically for mercury reduction. Although costs for remediation
projects are site specific, there are some methods for predicting costs
through identification and assessment techniques. This report provides
an overview of the costs associated with mercury remediation projects in
California, along with mitigation strategies in reducing mercury
contamination.

# I. Introduction

Regional Water Quality Control Board (RWQCB) staff are currently
preparing total maximum daily loads (TMDL) for mercury in California.
The objective of a mercury TMDL is to lower mercury levels so that the
beneficial uses of a water body are fully supported (CVRWQCB, 2001a,b).
In California, the Porter-Cologne Act (PCA) requires that economic
considerations must be one of the factors considered when establishing a
TMDL and mercury control program (PCA §13241, 2003).

The RWQCBs "must consider economics in establishing water-quality
objectives[^1] that ensure the reasonable protection of beneficial uses"
(Vassey, 1999). In addition, the Environmental Protection Agency's (EPA)
guidance states that the RWQCB must analyze the costs of methods to
achieve compliance with proposed objectives. However, RWQCBs are not
required to do a formal cost-benefit analysis (Vassey, 1999). The
initial step in this direction of analyzing different technologies for
mercury remediation is assessing mercury remedial options and their
costs.

Economic considerations include exploring the costs associated with the
various remedial practices that are applicable to mercury sources in a
water body. This report will outline the general remedial strategies,
along with remediation activities and costs associated with each of the
remedial alternatives. Various questions, concerns, and issues arise
when quantifying remediation costs. Therefore, this report will describe
the remediation process and how it affects cost predictions for
remediation projects. It will discuss potential remediation control
strategies to help make mercury remediation decisions for the future. In
addition, detailed information on past, present, and proposed
remediation projects involving mercury will be provided.

Information on remediation costs was collected on numerous projects and
sites for different years. For comparison purposes, a Gross Domestic
Price (GDP) deflator was used to adjust costs from one year to another
using a GDP deflator inflation index
([**http://www.jsc.nasa.gov/bu2/inflateGDP.html**](http://www.jsc.nasa.gov/bu2/inflateGDP.html)).
All of the costs in the text of this document report 2003 deflator
costs. For original cost estimates, please review citations.

# II. Mercury Remedial Options Summary 

The TMDL water quality objectives (WQO) and water quality program will
result in impacts on the regulated community, including costs of
mitigation measures, as well as time requirements for permits, reports,
and administration. Each water quality control program will most likely
require a suite of the following point-source (PS) and nonpoint-source
(NPS) remedial strategies:

-   Gold and mercury mine remediation: stabilizing pit walls, removing
    sluice boxes, plugging sluice tunnels, backfilling mine pits

-   Mercury reduction programs: mercury recycling and collection

-   Sediment management: erosion control activities in areas that supply
    sediment with high mercury levels

-   Ecosystem restoration: wetland modification projects

This section of the report provides a summary of the different
remediation strategies and general costs. Remedial practices associated
with each of these strategies along with their unit costs, "per foot,"
"per cubic yard," or "per acre," are listed. We note, however, that unit
costs do not translate readily to remediation technology costs in
general or mine remediation specifically. Remediation unit costs are
site specific and must always be considered in terms of how closely the
site conditions match the conditions that were present when/where the
unit costs were derived. Economies of scale can alter unit costs as
well. These costs may comprise the following:

-   Project plan development (technical designs and alternatives
    analysis)

• Determination of environmental effects and compliance with the
California Environmental Quality Act (CEQA), National Environmental
Policy Act (NEPA), CWA, and other applicable local, State, and Federal
environmental regulations

• Acquisition of other nonenvironmental approvals and permits

• Construction, long-term maintenance, and monitoring

(Wood, 2002)

Table 1. Summary of mercury remediation projects/technologies/programs
(Wood, 2003)

<table>
<colgroup>
<col style="width: 14%" />
<col style="width: 1%" />
<col style="width: 3%" />
<col style="width: 0%" />
<col style="width: 13%" />
<col style="width: 5%" />
<col style="width: 0%" />
<col style="width: 0%" />
<col style="width: 11%" />
<col style="width: 1%" />
<col style="width: 0%" />
<col style="width: 19%" />
<col style="width: 0%" />
<col style="width: 4%" />
<col style="width: 1%" />
<col style="width: 0%" />
<col style="width: 20%" />
</colgroup>
<tbody>
<tr class="odd">
<td colspan="17"><p id="mercury-hg-mine-sites-in-california"
class="heading"> <em>Mercury (Hg) Mine Sites in California</em></p></td>
</tr>
<tr class="even">
<td>Project</td>
<td colspan="5">Location (County)</td>
<td colspan="4">Volume</td>
<td colspan="4">Total Cost ($)</td>
<td colspan="3">Unit Costs ($)</td>
</tr>
<tr class="odd">
<td>Buena Vista</td>
<td colspan="5">San Luis Obispo</td>
<td colspan="4">474,100 CY</td>
<td colspan="4">1,349,754–7,758,188</td>
<td colspan="3">2.85–16.36/CY</td>
</tr>
<tr class="even">
<td>Gambonini</td>
<td colspan="5">Marin</td>
<td colspan="4">218,000 CY</td>
<td colspan="4">3.06–3.67 million</td>
<td colspan="3">14.04–16.84/CY</td>
</tr>
<tr class="odd">
<td>Polar Star Mine</td>
<td colspan="5">Placer</td>
<td colspan="4">500 CY</td>
<td colspan="4">1.56 million</td>
<td colspan="3">3,120/CY</td>
</tr>
<tr class="even">
<td>Sulphur Bank</td>
<td colspan="5">Lake</td>
<td colspan="4">193,600 CY</td>
<td colspan="4">180,000–69.5 million</td>
<td colspan="3">0.93–358.99/CY</td>
</tr>
<tr class="odd">
<td>Gibraltar</td>
<td colspan="5">Santa Barbara</td>
<td colspan="4">5,555 CY</td>
<td colspan="4">282,804–572,997 (without contracting–with contracting
costs)</td>
<td colspan="3">50.91–103.15/CY</td>
</tr>
<tr class="even">
<td>Aurora</td>
<td colspan="5">San Benito</td>
<td colspan="4">1,630 CY</td>
<td colspan="4">15,300</td>
<td colspan="3">9.39/CY</td>
</tr>
<tr class="odd">
<td>Alpine</td>
<td colspan="5">San Benito</td>
<td colspan="4">6,500 CY</td>
<td colspan="4">127,500–331,500</td>
<td colspan="3">19.62–51/CY</td>
</tr>
<tr class="even">
<td>Carson River</td>
<td colspan="5">Lyon, Storey, Churchill, (Calif./Nev.)</td>
<td colspan="4">9,087 CY</td>
<td colspan="4">3,200,000–3,350,214</td>
<td colspan="3">352.15–368.68/CY</td>
</tr>
<tr class="odd">
<td>New Almaden</td>
<td colspan="5">Santa Clara</td>
<td colspan="4">2,500 CY</td>
<td colspan="4">3,996,000</td>
<td colspan="3">1598.40/CY</td>
</tr>
<tr class="even">
<td colspan="14">Total Unit Costs for Mercury Mine Sites</td>
<td colspan="3">0.93–15.98/CY</td>
</tr>
<tr class="odd">
<td colspan="17"><em>Hg Remediation Techniques, Technologies, and
Programs</em></td>
</tr>
<tr class="even">
<td colspan="2">Type</td>
<td colspan="3">Description</td>
<td colspan="4">Area/Volume</td>
<td colspan="3">Total Cost ($)</td>
<td colspan="5">Unit Costs ($)</td>
</tr>
<tr class="odd">
<td colspan="2">Encapsulation (study)</td>
<td colspan="3">Acid mine drainage</td>
<td colspan="4"><h6
id="amt.-of-binder-depends-on-acid-type-510-cement-binder">Amt. of
binder depends on acid type, (5­­–10% cement binder)</h6></td>
<td colspan="3">N/A</td>
<td colspan="5">12.90–16.10/ton</td>
</tr>
<tr class="even">
<td colspan="2">Living island (research)</td>
<td colspan="3">Using plants</td>
<td colspan="4"><h6 id="na">N/A</h6></td>
<td colspan="3">3.37–5.87 million</td>
<td colspan="5">N/A</td>
</tr>
<tr class="odd">
<td colspan="2">Scoop/bury (study)</td>
<td colspan="3">Interferes with methylation cycle</td>
<td colspan="4"><h6 id="na-1">N/A</h6></td>
<td colspan="3">35,700–120,360</td>
<td colspan="5">35,700­­–120,360</td>
</tr>
<tr class="even">
<td colspan="2">Passivation (study)</td>
<td colspan="3">Coats tailings to prevent Hg</td>
<td colspan="4"><h6 id="ac">65 AC</h6></td>
<td colspan="3">239,654–288,370</td>
<td colspan="5">0.32–0.54/ton; 3,687–4,436/AC</td>
</tr>
<tr class="odd">
<td colspan="2">Soil washing (study)</td>
<td colspan="3">Ex situ treatment;</td>
<td colspan="4"><h6 id="tons">25,000–200,000 tons</h6></td>
<td colspan="3">7,335,000–34,640,000</td>
<td colspan="5">171.8–293.4/ton</td>
</tr>
<tr class="even">
<td colspan="2" rowspan="4">Recycling programs</td>
<td colspan="3" rowspan="4">Collection efforts</td>
<td colspan="4">220 lb</td>
<td colspan="3">1,248</td>
<td colspan="5">5.67/lb</td>
</tr>
<tr class="odd">
<td colspan="4">15 lb</td>
<td colspan="3">102</td>
<td colspan="5">6.8/lb</td>
</tr>
<tr class="even">
<td colspan="4">200–300 lb</td>
<td colspan="3">10,640–11,064</td>
<td colspan="5">35.45–55.32/lb</td>
</tr>
<tr class="odd">
<td colspan="4">73 lb</td>
<td colspan="3">4392.28</td>
<td colspan="5">60.17/lb</td>
</tr>
<tr class="even">
<td colspan="2">Acid leaching (study)</td>
<td colspan="3">Changes Hg species</td>
<td colspan="4"><h6 id="tonshr">6–8 tons/hr</h6></td>
<td colspan="3">2,910–17,232</td>
<td colspan="5">485–2,154/ton</td>
</tr>
<tr class="odd">
<td colspan="2">Retorting (study)</td>
<td colspan="3">Altering transport mechanisms</td>
<td colspan="4"><h6 id="tonsday">3–12 tons/day</h6></td>
<td colspan="3">1,617–25,848</td>
<td colspan="5">539–2,154</td>
</tr>
<tr class="even">
<td colspan="2" rowspan="2">Hg transportable stabilization system</td>
<td colspan="3" rowspan="2">Treats contaminated water</td>
<td colspan="4" rowspan="2"><h6 id="hrs-12000-lb">10 hrs; 12,000
lb</h6></td>
<td colspan="3" rowspan="2">32,846</td>
<td colspan="5">Capital costs: 31,836; 2.65/lb</td>
</tr>
<tr class="odd">
<td colspan="5">Operating costs: 101/hr; 11.88/lb</td>
</tr>
<tr class="even">
<td colspan="2">Sorbents (research tests)</td>
<td colspan="3">Chemical removal of Hg</td>
<td colspan="4"><h6 id="kg-of-hg">10 kg of Hg</h6></td>
<td colspan="3">8,900–86,430</td>
<td colspan="5">890–8,643 to remove 1 kg of Hg</td>
</tr>
<tr class="odd">
<td colspan="2">Amalgamation using NFS DeHg</td>
<td colspan="3">Stabilizes elemental Hg</td>
<td colspan="4"><h6 id="kg">1,500 kg</h6></td>
<td colspan="3">484,500</td>
<td colspan="5">323/kg of Hg removed</td>
</tr>
<tr class="even">
<td colspan="2">Polymer filtration technology</td>
<td colspan="3">Washing and leaching elemental/ionic forms of Hg</td>
<td colspan="4"><h6 id="tons-1">Tons</h6></td>
<td colspan="3">898/yr</td>
<td colspan="5">21.54–876/ton</td>
</tr>
<tr class="odd">
<td colspan="2" rowspan="2">Acid rock drainage</td>
<td colspan="3">Waste rock piles</td>
<td colspan="4">Ton of waste</td>
<td colspan="3" rowspan="2">Research study</td>
<td colspan="5">10.87–49.32/ton</td>
</tr>
<tr class="even">
<td colspan="3">Tailings</td>
<td colspan="4"><h6 id="acre-of-tailings">Acre of tailings</h6></td>
<td colspan="5">1,139,288–3,265,803/AC</td>
</tr>
<tr class="odd">
<td colspan="12">Total Unit Costs for Hg Controls</td>
<td colspan="5">0.32–2,154/ton; 2.65–60.17/lb; 323–8,643/ kg of Hg
removed</td>
</tr>
<tr class="even">
<td colspan="17"><em>Contaminated Sediment/Erosion Control
Activities</em></td>
</tr>
<tr class="odd">
<td colspan="3">Type</td>
<td colspan="4">Description</td>
<td colspan="4">Area/Volme</td>
<td colspan="2">Total Cost</td>
<td colspan="4">Unit Costs ($)</td>
</tr>
<tr class="even">
<td colspan="3">Klau Mine: sedimentation basin</td>
<td colspan="4">Sediment control</td>
<td colspan="4">150,000 CF</td>
<td colspan="2">65,466</td>
<td colspan="4">0.44/CF</td>
</tr>
<tr class="odd">
<td colspan="3">Klau Mine: Sediment basin maintenance</td>
<td colspan="4">Maintaining basin</td>
<td colspan="4">50 AC</td>
<td colspan="2">38,189</td>
<td colspan="4">764/AC</td>
</tr>
<tr class="even">
<td colspan="3">Klau Mine</td>
<td colspan="4">Seeding and mulching</td>
<td colspan="4">16 AC</td>
<td colspan="2">19,203</td>
<td colspan="4">1,200/AC</td>
</tr>
<tr class="odd">
<td colspan="3">Buena Vista Mine</td>
<td colspan="4">Haul road construction; runoff ditches</td>
<td colspan="4">8,300 LF</td>
<td colspan="2">32,024</td>
<td colspan="4">3.86/LF</td>
</tr>
<tr class="even">
<td colspan="3">Clear lake</td>
<td colspan="4">Dredging</td>
<td colspan="4">1,050 AC</td>
<td colspan="2">57–949 million</td>
<td colspan="4">54,286–903,806/AC</td>
</tr>
<tr class="odd">
<td colspan="3">Hydraulic mines</td>
<td colspan="4"><p>Solidification/</p>
<p>stabilization</p></td>
<td colspan="4">N/A</td>
<td colspan="2">N/A</td>
<td colspan="4">41–230/CY</td>
</tr>
<tr class="even">
<td colspan="13"><strong>Total Unit Costs for Erosion Control
Activities</strong></td>
<td colspan="4">41–230/CY; 764–903,806/AC</td>
</tr>
<tr class="odd">
<td colspan="17"><em>Ecosystem Modification Projects</em></td>
</tr>
<tr class="even">
<td colspan="4"><p id="type" class="heading">Type</p></td>
<td colspan="4"><strong>Description</strong></td>
<td colspan="2"><strong>Area/ Volume</strong></td>
<td colspan="6"><p id="total-cost" class="heading">Total Cost
($)</p></td>
<td><strong>Unit Costs</strong> ($)</td>
</tr>
<tr class="odd">
<td colspan="4"><p id="constructed-wetlands" class="heading">Constructed
wetlands</p></td>
<td colspan="4">Reduce methylation</td>
<td colspan="2">N/A AC</td>
<td colspan="6"><p id="na-2" class="heading">N/A</p></td>
<td>50,000–150,000</td>
</tr>
<tr class="even">
<td colspan="4"><p id="suisin-marsh-and-sf-bay-proposed"
class="heading">Suisin Marsh and SF Bay (proposed)</p></td>
<td colspan="4"><p id="biological-restoration"
class="heading">Biological restoration/</p>
<p>monitoring</p></td>
<td colspan="2">272 AC</td>
<td colspan="6"><p id="section-1" class="heading">772,667</p></td>
<td>2,841/AC</td>
</tr>
<tr class="odd">
<td colspan="4"><p id="suisan-marsh-bahia" class="heading">Suisan Marsh,
Bahia </p></td>
<td colspan="4">Land acquisitions</td>
<td colspan="2">N/A</td>
<td colspan="6"><p id="section-2"
class="heading">1,046,000–3,345,000</p></td>
<td><p>1,046,000–3,345,000/</p>
<p>acquisition</p></td>
</tr>
<tr class="even">
<td colspan="4"><p id="calfed-research-studies" class="heading">CALFED
research studies</p></td>
<td colspan="4">Reducing methylation</td>
<td colspan="2">N/A</td>
<td colspan="6"><p id="section-3"
class="heading">300,000–3,881,215</p></td>
<td>300,000–3,881,215/study</td>
</tr>
<tr class="odd">
<td colspan="4"><p id="section-4" class="heading"></p></td>
<td colspan="4">Monitoring</td>
<td colspan="2"></td>
<td colspan="6"><p id="section-5" class="heading"></p></td>
<td>88,296–136,325</td>
</tr>
<tr class="even">
<td colspan="4"><p id="acid-rock-drainage" class="heading">Acid rock
drainage</p></td>
<td colspan="4">Evaporation</td>
<td colspan="2">N/A</td>
<td colspan="6"><p id="na-3" class="heading">N/A</p></td>
<td>2,519–9,329/gal/min</td>
</tr>
<tr class="odd">
<td colspan="4"><p id="section-6" class="heading"></p></td>
<td colspan="4">Passive wetland</td>
<td colspan="2"></td>
<td colspan="6"><p id="section-7" class="heading"></p></td>
<td>3,459–21,671/gal/min</td>
</tr>
<tr class="even">
<td colspan="4"><p id="section-8" class="heading"></p></td>
<td colspan="4">Lime precipitation</td>
<td colspan="2"></td>
<td colspan="6"><p id="section-9" class="heading"></p></td>
<td>4,124-11,454/gal/min</td>
</tr>
<tr class="odd">
<td colspan="16">Total Unit Costs for Ecosystem Modification</td>
<td>2,519–21,671/gal/min; 300,000–3,881,215/study; 2,841–150,000/AC</td>
</tr>
<tr class="even">
<td colspan="17"><em>Wastewater Treatment Plant Hg reduction
options</em></td>
</tr>
<tr class="odd">
<td colspan="3" rowspan="6">Sacramento Regional County Sanitation
District</td>
<td colspan="4">Chemically enhanced primary treatment</td>
<td colspan="4" rowspan="6">MGD</td>
<td colspan="4" rowspan="6">N/A</td>
<td colspan="2">75,250–76,755</td>
</tr>
<tr class="even">
<td colspan="4">Multimedia filtration</td>
<td colspan="2">500,120–510,122</td>
</tr>
<tr class="odd">
<td colspan="4">Micro filtration</td>
<td colspan="2">1,900,450–1,938,459</td>
</tr>
<tr class="even">
<td colspan="4">Reverse osmosis</td>
<td colspan="2">877,000–3,571,020</td>
</tr>
<tr class="odd">
<td colspan="4">Ion exchange</td>
<td colspan="2">900,000</td>
</tr>
<tr class="even">
<td colspan="4">Brine treatment</td>
<td colspan="2">146,000</td>
</tr>
<tr class="odd">
<td colspan="15"><strong>Total Unit Costs for Wastewater Treatment Plant
Hg Reduction</strong></td>
<td colspan="2">75,250–3,571,020 MGD</td>
</tr>
</tbody>
</table>

# III. Historical And Future Mining Remediation Projects[^2]

This section of the report details some of the remediation projects that
have been carried out in California. Reviews of each of these projects
include descriptive information (project size and location), project
costs, and total and unit costs. Unit costs do not translate readily to
remediation technology costs in general. Remediation unit costs are site
specific and must always be considered in terms of how closely the site
conditions match the conditions that were present when/where the unit
costs were derived.

Point sources, regulated under a National Pollutant Discharge
Elimination System (NPDES) permit, are initially targeted to reduce
pollution from their systems before regulators focus on NPS problems.
Although this analysis will focus on NPS remedial strategies, section A
will initially concentrate on PS reduction opportunities. Many different
local, State, and Federal agencies, in addition to consultants,
engineers, geologists, hydrologists, and academic researchers, assisted
in developing this economic analysis.

## A. Point-Source Reductions

Regulators initially target PSs (that is, wastewater treatment
facilities, industrial facilities, and so on) for contaminant
reductions, because they are easier to regulate and monitor. This
section will briefly give an overview of potential costs for one
treatment facility, the Sacramento Regional County Sanitation District
(SRCSD). The SRCSD was issued an NPDES Permit in August 2000 requiring
the submittal of an offset (pollutant trading) feasibility study and
also a treatment feasibility study for mercury (SRCSD, 2001). The SRCSD
is still in the early stages of both of these studies; however, various
treatment alternatives have been screened. The treatment alternatives,
along with preliminary mercury removal efficiencies and project costs,
are listed in table 2.

Table 2. Mercury treatment alternatives for SRCSD

(after Carollo, 2002)[^3]

+------------+--------+----------+-----------+----------+-----------+
| Treatment  | P      | O& M     | A         | Ad       | Mercury   |
| a          | roject | cost     | dditional | ditional | removal   |
| lternative | cost   | (\$/MG)  | sewer     | sewer    | eff       |
|            | (\$/M  | ^5^      | service   | co       | iciencies |
|            | GD^3^) | (price   | charge    | nnecting |           |
|            | ^4^    | d        | (\$E      | charge   |           |
|            | (price | eflator) | SD/month) | (\$E     |           |
|            | def    |          | ^6^       | SD/mon.) |           |
|            | lator) |          |           |          |           |
+------------+--------+----------+-----------+----------+-----------+
| Chemically | 75,000 | 250      | 2.50      | 25       | 97%       |
| enhanced   |        |          |           |          |           |
| primary    | (7     | \(255\)  |           |          |           |
| treatment  | 6,500) |          |           |          |           |
| (CEPT)^1^  |        |          |           |          |           |
+------------+--------+----------+-----------+----------+-----------+
| Multimedia | 5      | 120      | 2.20      | 150      | 96%       |
| filtration | 00,000 |          |           |          |           |
|            |        | \(122\)  |           |          |           |
|            | (51    |          |           |          |           |
|            | 0,000) |          |           |          |           |
+------------+--------+----------+-----------+----------+-----------+
| Micro      | 1,9    | 450      | 8.25      | 570      | 97%       |
| filtration | 00,000 |          |           |          |           |
|            |        | \(459\)  |           |          |           |
|            | (1,93  |          |           |          |           |
|            | 8,000) |          |           |          |           |
+------------+--------+----------+-----------+----------+-----------+
| Reverse    | 3,5    | 1,000    | 16.80     | 1,050    | 98%       |
| osmosis^2^ | 00,000 |          |           |          |           |
|            |        | (1,020)  |           |          |           |
|            | (3,57  |          |           |          |           |
|            | 0,000) |          |           |          |           |
+------------+--------+----------+-----------+----------+-----------+

1\. CEPT costs are based on retrofit of existing facility.

2\. Assumes microfiltration (MF) needed as pretreatment step and
includes MF costs.

3\. Million gallons per day.

4\. Based on averaged day maximum flows conditions, Engineering News
Record Construction Costs Index (ENRCCI) of 6,615 and includes
engineering, legal, administrative, and CEQA costs.

5\. Operation and Maintenance costs are based on average day annual flow
(ADAF) conditions

6\. 300 GPD per Equivalent Single-Family Dwelling (ESD); capital
financing at i=6%, N=20 yr.

In addition, an EPA report, Mercury Study Report to Congress, documents
mercury control technologies and costs/financial impact estimates for
four different industries: municipal waste combustors, medical waste
incinerators, utility boilers, and chlor--alkali plants (EPA, 1997). The
report provides information on mercury control strategies, with cost
estimates and mercury removal efficiencies.

## B. Mercury Mine Sites 

Although mercury comes from several sources within the Sacramento Delta
and its tributary watersheds, past research and monitoring data indicate
that most of the mercury comes from historic mining operation discharges
in the Coast Ranges and Sierra Nevada. The following section describes
some of these historic mining operations throughout California.

**Buena Vista/Klau Mercury Mine Site**

The Buena Vista/Klau Mercury Mine, located approximately 12 miles west
of Paso Robles, San Luis Obispo County, consists of two parcels of
property and 175 acres (Suter, 2001). Mining operations, beginning in
the late 1860s and continuing until 1970, contributed mine waste and
tailings in drainage channels. Episodic weather events left deep
erosional channels throughout the site, thereby releasing mercury-laden
sediment, which had impacts on the Las Tablas Creek and the Lake
Nacimiento Reservoir (Suter, 2001).

At the Buena Vista Mine site, an engineering evaluation study
(\$43,084), permitting (\$107,710), and engineering design (\$53,855)
are examples of preliminary administrative activities and costs before
any remedial action (SECOR, 1999). In addition, 920 yd^3^ were moved to
the Klau repository and 7,620 yd^3^ were moved to stabilize the slope
below the county road. Remediation activities up until May 23, 2001,
have an estimated cost of \$2,691,152 (Suter, 2001). Final compliance
cost estimates are shown in appendix A.

Contact: Gerhardt Hubner (CA RWQCB) (<ghubner@rb3.swrcb.ca.gov>)

**Gambonini Mercury Mine**

The Gambonini Mercury Mine, located in the steep headwaters region of
the Tomales Bay watershed, is approximately 10 miles west of Petaluma,
Calif. (Smelser and Whyte, 2002). The Gambonini Mine is a 16-acre
mercury mine residing on a geologically unstable site. The development
and implementation of an appropriate remediation plan was a long and
arduous process. Problem identification, funding negotiations,
remediation plan development, and construction required approximately 13
years (with the involvement of four government agencies and a group of
engineering geologists).

The Gambonini remediation plan required (1) a highly accurate
topographic base map, (2) an analysis of historic aerial photographs,
(3) detailed field mapping, and (4) subsurface investigations (Smelser
and Whyte, 2002). The objective of this remediation project was to
stabilize the primary mine waste deposit and reduce the discharge of
mercury-laden sediment, map the distribution of mine waste, and
reestimate the volume of primary mine waste deposit. The project
required the removal of approximately 218,000 yd^3^ of mine waste and
weathered bedrock from 5 acres in the upper half of the area (Smesler
and Whyte, 2002). In response to 1998's rainy season and mine discharge
of 82 kg of Hg, engineers began a gravity buttress stabilization project
costing \$1.6 million at a unit cost of \$102,290/acre (Lunceford,
2001). Detailed site characterizations were crucial in developing
appropriate remediation measures, accurate cost estimates, and efficient
project implementation. Table 3 documents the remediation techniques
that were assessed as possible remediation alternatives for the
Gambonini Mercury Mine (Note: agencies chose to construct the gravity
buttress).

Table 3. Remediation alternatives for the Gambonini Mercury Mine
(Smelser and Whyte, 2002)

+---------------------+-----------+-----------------------+------------+
| Remediation         | A         | Disadvantages         | Estimated  |
| Technique           | dvantages |                       | cost       |
+---------------------+-----------+-----------------------+------------+
| Removing all mine   | Mine      | -Mercury-laden        | \          |
| waste from the      | waste     | exposure at surface   | $4.59--5.1 |
| slope area and      | isolated  |                       | million    |
| placing it in the   |           | -Minimum of 2 months  |            |
| pit                 |           | required to complete  |            |
|                     |           | investment            |            |
|                     |           |                       |            |
|                     |           | -Potential high       |            |
|                     |           | construction costs    |            |
|                     |           |                       |            |
|                     |           | -Does not stabilize   |            |
|                     |           | bedrock landslides    |            |
+---------------------+-----------+-----------------------+------------+
| Stabilizing the     | Minimal   | -Mercury-laden mine   | \$         |
| waste material in   | grading   | waste exposed at      | 2.96--3.57 |
| place by building a |           | surface               | million    |
| large retaining     |           |                       |            |
| wall                |           | -Minimum of 2 months  |            |
|                     |           | required to complete  |            |
|                     |           | investigation and     |            |
|                     |           | design                |            |
|                     |           |                       |            |
|                     |           | -Potential high       |            |
|                     |           | construction costs    |            |
+---------------------+-----------+-----------------------+------------+
| Stabilizing the     | -Simple   | Mercury-laden mine    | \$         |
| waste material in   | cons      | waste exposed at the  | 3.06--3.67 |
| place and using a   | truction; | surface               | million    |
| gravity buttress    |           |                       |            |
| (\*\*agency choice) | easier    |                       |            |
|                     | grading   |                       |            |
+---------------------+-----------+-----------------------+------------+

Contact: Dyan Whyte (Calif., RWQCB) (<dcw@rb2.swrcb.ca.gov>).

Polar Star Mine (PSM)

The Polar Star Mine, located near Dutch Flat, Calif., 30 miles northeast
of Auburn, Calif., in Placer county, is an abandoned placer gold mine
where hydraulic techniques were used to transport water and gravels
through tunnels containing a sluice box. The removal action reduced but
did not eliminate sources of mercury loading. The amount of reduction is
unknown. Specifically, the cleanup approach consisted of the following
steps (field work started in May 2000):

-   Develop a comprehensive site safety plan for all activities

-   Inspect PSM tunnel and implement recommendations regarding tunnel
    stability, ventilation, and safety

-   Contain ground water flowing through the tunnel before start of
    field work

-   Excavate/remove wooden sluice box and boulders from PSM tunnel

-   Remove mercury-contaminated gravels and arrange for transportation
    and disposal of such gravels

> (EPA, 2000)

The remediation action by EPA consisted of removing contaminated
sediment and the sluice box assembly from the site and sending it to a
hazardous waste landfill. The entire length of the tunnel was then lined
with concrete to prevent contaminated sediment from reaching the Bear
River and to stop small-scale panning at the site. The EPA Emergency
Response Unit successfully used the sediment removal technique costing
nearly \$1.56 million to clean up 500 yd of tunnel/sluice (Lawler, 2001;
Lunceford, 2001).

Contact: Rick Humphreys (SWRCB) (<humpr@swrcb.ca.gov>)

Sulphur Bank Mercury Mine Superfund Site (SBMM)

The 120-acre Sulphur Bank Mercury Mine Site, located near Clear Lake
Oaks, Calif., was mined for sulfur (1856--71) and mined intermittently
by underground methods (1873--1905) and pit mining (1915--57) (EPA,
2002). The mine tailings extend into the Clear Lake Oaks Water District
that provides municipal drinking water for 4,700 people (EPA, 2002). The
SBMM is currently owned by the Bradley Mining Company, which the EPA has
identified as the potentially responsible party (Cooke and Morris,
2002). In addition, Superfund has already obligated approximately \$5.1
million for remediation (Tinsley, 2002). On November 1, 1999,
contractors hired by the U.S. Army Corps of Engineers, through an EPA
contract, constructed surface water diversions on and near the mine
site, preventing contaminated sediments and water from flowing into
Clear Lake, Herman Pit, and offsite. Other response actions included
storm-water controls, soil removal and impoundment, and lake sediment
investigations (CVRWQCB, 2001).

The RWQCB's "Amendment to the Water Quality Control Plan for the
Sacramento River and San Joaquin River Basins for the Control of Mercury
in Clear Lake" draft report provides estimated costs of potential
remediation activities. Appendix B describes some of the potential
remediation actions and costs (Cooke and Morris, 2002).

Contact: Patrick Morris (CA RWQCB) (<MorrisP@rb5s.swrcb.ca.gov>)

**Gibraltar Mine and Mill**

The Gibraltar Mine and Mill site, an abandoned mining facility since
1991, is located on Federal land under the jurisdiction and control of
the U.S. Department of Agriculture Forest Service (DeGraff, 2000).
Located within the Santa Barbara Ranger District of the Los Padres
National Forest, the site encompasses an area adjacent to the Gibraltar
Reservoir within the Santa Ynez River watershed. The main concern of the
site was the potential exposure to free mercury within the main mill
building (DeGraff, 2000). Mercury contamination was caused at this site
through the creation of waste spillage to the milling and mining
operation and lack of reclamation. Onsite removal activities began in
the early summer of 1999, after a number of environmental and economic
assessments were completed (Ecology and Environment, 1999).

During fiscal year 1999, costs included direct costs for removal actions
(\$36,509) and also for mine reclamation work (\$246,295) totaling
\$282,804 (DeGraff, 2000). Contracts costs to Ecology and the
Environment totaled \$290,193 (DeGraff, 2000). Costs not included in
these figures are those for reconstruction of the access road,
addressing the biologic impacts, and oversight time by the onscene
coordinator. Removal actions were considered to be effective since the
highest concentrations of mercury at the Gibraltar Mine and Mill site
were removed from the condenser troughs.

Contact: Jerome Degraff (USFS) (<jdegraff@fs.fed.us>)

New Idria Mine Area (Five abandoned mercury retort sites)

In the larger New Idria mine area, remediation took place at the Aurora
and Alpine Mines. Remediation took place at three very small mine sites,
approximately 1--5 acres, costing under \$15,300. The costs were low
because of the simple design of the tailings, and retorts/buildings were
buried in a large hole (repository). These small sites were completed
within 5 days. Remediation at two larger mines (5--10 acres) was
completed in 1--2 months and involved 5,000--8,000 yd^3^ of retorted
ore. These larger sites cost approximately \$127,500--331,500 (Tim
Moore, written commun., 2002).

Contact: Tim Moore (BLM) (<Timothy_Moore@ca.blm.gov>).

*Carson River Mercury Site* *(Nevada/California)*

Located in Carson, Nevada, in Lyon, Storey, and Churchill Counties, the
Carson River Mercury Site is the only site in Nevada listed on the
Superfund National Priorities List (NPL). This site includes
mercury-contaminated soils at former mill sites and mercury
contamination in sediments, fish, and wildlife over more than a 50-mile
length of the Carson River.

In 1998--99, the EPA completed a \$3.27 million cleanup of
mercury-contaminated upland soils at the site. Approximately \$3.88
million has been obligated through Superfund's NPL (Tinsley, 2002). The
EPA has not attempted or completed any cleanup in the
river-reservoir-wetland system. The EPA has been conducting an
ecological risk assessment at the site since the early 1990s. A Remedial
Investigation and Feasibility Study was conducted in the initial phase
in 1993 and its final cleanup plan (Record of Decision (ROD)) was
adopted in 1995. The remedy selected in the ROD included excavation of
approximately 5,000 yd^3^ of contaminated soils exceeding 80 parts per
million (ppm) mercury to a maximum depth of 2 feet, backfilling with
clean soil, restoration after excavation and backfilling, and offsite
disposal of contaminated soil (Ecology and Environment, 2000).

Remedial decisions were based on risk assessments---where there were
elevated mercury levels (in soil) and where people were living (toxicity
values). The EPA located 100 mills in the area and on the basis of
health risks identified 4 mills (areas) that needed to be remediated
(all upland areas, including 12 homes). This remediation plan displaced
people under the Uniform Relocation Act in which people were compensated
with fair market prices for their property. Construction---digging and
transporting contaminated soil away from the site (social/environmental
costs)---lasted 6 months and cost \$3 million. Appendix C illustrates
these costs (with 2003 deflator costs) in more detail.

Other notable transaction costs included the following:

-   Additional construction costs to excavate and dispose of high Hg
    soils (additional \$742,840)

-   Compliance with environmental standards (Historical Preservation Act
    Requirements) (additional \$315,176)

-   Change orders---to account for changed field conditions, and so on
    (additional \$275,912)

-   Construction delays---increased length of cleanup, thus increasing
    EPA/E&E oversight costs and onsite field office costs for the
    remedial subcontractor (additional \$31,835-47,754)

    (Ecology and Environment, 2000)

Contact: Wayne Praskins (EPA Region IX) (<praskins.wayne@epa.gov>).

###  {#section-10}

## C. Proposed Mine Remediation Sites 

As more research and site characterizations have been undertaken at
various mine sites in response to water quality standards and the TMDL
process, more remediation projects within California have been evolving.
Detailed site characterizations and preliminary cost figure estimates
were done for proposed actions at the following mine sites.

**Sailor Flat Hydraulic Mine Site**

The Sailor Flat (East) Hydraulic Mine site, located on land administered
by the U.S. Forest Service (USFS), (Federal mining claim), approximately
8 miles east of Nevada City, Calif., is a pit 2--3 acres in size created
by hydraulic mining techniques, placer mining, logging, and an
associated drain tunnel (DeGraff, 2002). Mining activities occurred
primarily from the 1850s to 1900, with activities thereafter consisting
of small-scale excavations and building improvements. Main features of
the site are the mine pit and a 120-foot-long drain tunnel. The former
gold mine has both onsite and offsite problems with mercury
contamination. Sampling results of water entering and leaving the drain
tunnel suggest high levels of mercury contamination in the surface
water, in addition to methylation occurrences. Sampling activities and
observations have led researchers to conclude that response actions will
require mitigating the surface water contamination within the hydraulic
pit and discharging from the drain tunnel. In addition, some type of
removal of mercury-contaminated wood from sluices will also need to be
done (DeGraff, 2002).

The USFS has been selected to conduct a nontime-critical remediation of
the Sailor Flat mine site. An engineering evaluation and a cost analysis
(EE/CA) for several proposed alternatives were made available for public
comment in July 2002. The proposed action is an "excavation and fill"
technique (Rick Weaver, oral commun., 2003).

The following proposed actions were evaluated:

1.  Excavate and fill: The soil and rock above the tunnel would be
    excavated by machine to expose the tunnel, then a concrete or
    polymer synthetic mixture would be pumped into the sluice cut to
    stabilize and solidify the contaminated sediment. The estimated cost
    of this alternative is \$139,973.

2.  Isolate and plug: Mercury-contaminated sediments would be isolated
    to prevent further methylation in the future. The steps taken in
    this remediation action are similar to those in the first option.
    Contaminated sediments would be stabilized with a concrete or
    polymer synthetic mixture. The vertical inlet to the tunnel would be
    plugged with an impermeable barrier, and the remaining volume of the
    inlet would be filled with excavated material. The outlet end would
    be blocked with a steel gate. Estimated cost of this alternative is
    \$177,738.

> (USFS, 2003)
>
> Both alternatives would also involve the treatment of
> mercury-impregnated wood from old sluices.
>
> The USFS chose the first alternative as most cost effective. The
> project is still in the design phase, and a new estimate of the total
> cost is \>\$500,000 (R. Weaver, oral comm., 2003), which will require
> additional sources of funding.

### **Buckeye Diggings Hydraulic Mine**

Also located in Nevada City, Calif., the Buckeye Diggings Mine was found
to have been releasing hazardous substances to the environment since
1852 (USFS, 2002). Miners constructed deep channels and tunnels to
sustain water pressure to conduct the hydraulic mining and recover gold.
Mercury was used extensively as part of the gold recovery process.
Nearly 20--30 percent of the mercury used in the sluice box was lost to
the downstream watershed as part of the gold recovery method (USFS,
2002). The preliminary assessment did not contain cost estimates for
mitigation actions.

###  {#section-11}

**Guadalupe River Watershed Preliminary Plan**

A recent report reviewed possible mercury remediation methods to be used
for sites within the Guadalupe River Watershed in San Jose, Calif.
(Fuller, 2002). The New Almaden Mine, located in the higher elevation of
the Guadalupe River, is the main contributor of mercury to this area.

An estimated 30-year cost estimate for various remediation strategies
for a 12 acre polluted site was "\$12,000,000 for excavation and
disposal, \$6,300,000 for soil washing, \$600,000 for a soil cap, and
\$200,000 for phytoextraction" (Fuller, 2002). Additional remediation
methods are mentioned in this paper (table 4).

Table 4. Potential remediation methods for the Guadalupe River Watershed
after Fuller, 2002)

+------------+---------+------+---------+----------+------------------+
| Method     | Desc    | Cost | Adv     | Disad    | Special          |
|            | ription |      | antages | vantages | Requirements     |
+------------+---------+------+---------+----------+------------------+
| [          | D       | \$   | Well    | Ex       | Expensive        |
| Removal]{. | redging | 1mil | -tested | pensive, | equipment; must  |
| underline} | and     | lion | and     | lengthy  | be monitored     |
|            | pumping | /AC  | ef      | process; | periodically and |
|            | out     |      | fective | disposal | followed by      |
|            | conta   |      |         | sites    | either treatment |
|            | minated |      |         | can      | and/or burial    |
|            | ma      |      |         | leak,    | and containment  |
|            | terials |      |         | release  | in other         |
|            |         |      |         | con      | location         |
|            |         |      |         | taminant |                  |
+------------+---------+------+---------+----------+------------------+
| [Tre       | [P      | \    | Good    | Does not | These methods    |
| atments]{. | hysical | $500 | for     | work     | often are best   |
| underline} | t       | ,000 | large   | with     | applied offsite  |
|            | reatmen |      | qua     | high     | in contaminated  |
|            | t]{.und | /AC  | ntities | silt,    | medium that has  |
|            | erline} |      | of      | clay     | been removed     |
|            |         |      | s       | content, |                  |
|            | (s      |      | ediment | soil/s   |                  |
|            | orting) |      | (20-40  | ediments |                  |
|            |         |      | t       |          |                  |
|            |         |      | ons/hr) |          |                  |
+------------+---------+------+---------+----------+------------------+
|            | [Therma |      | Hg      | Causes   |                  |
|            | l]{.und |      | co      | more     |                  |
|            | erline} |      | mpounds | atm      |                  |
|            |         |      | are     | ospheric |                  |
|            |         |      | highly  | Hg       |                  |
|            |         |      | v       |          |                  |
|            |         |      | olatile |          |                  |
|            |         |      | at low  |          |                  |
|            |         |      | tempe   |          |                  |
|            |         |      | ratures |          |                  |
+------------+---------+------+---------+----------+------------------+
|            | [       |      | Hg can  | Adding   |                  |
|            | Chemica |      | be made | foreign  |                  |
|            | l]{.und |      | biolo   | c        |                  |
|            | erline} |      | gically | hemicals |                  |
|            |         |      | unav    | into an  |                  |
|            |         |      | ailable | e        |                  |
|            |         |      |         | cosystem |                  |
|            |         |      |         | can be   |                  |
|            |         |      |         | d        |                  |
|            |         |      |         | angerous |                  |
+------------+---------+------+---------+----------+------------------+
| [Immobil   | P       | \    | Well    | High     | Barriers can be  |
| ization]{. | hysical | $50, | -tested | cost,    | top, bottom, or  |
| underline} | b       | 000/ | and     | barriers | lateral side     |
|            | arriers |      | ef      | are of   | barriers; some   |
|            | placed  | AC   | fective | ques     | can be natural   |
|            | on site |      |         | tionable | and not manmade  |
|            | to      |      |         | per      |                  |
|            | contain |      |         | manence, |                  |
|            | the     |      |         | unknown  |                  |
|            | cont    |      |         | ec       |                  |
|            | aminant |      |         | ological |                  |
|            |         |      |         | effects  |                  |
+------------+---------+------+---------+----------+------------------+
| [Microbial | M       | N/A  | Ef      | Not      | Forms the basis  |
| action]{.  | icrobes |      | fective | proven   | of               |
| underline} | can     |      | in      | for      | phytoremediation |
|            | deme    |      | s       | onsite   |                  |
|            | thylate |      | ludges, | rem      |                  |
|            | Hg      |      | wast    | ediation |                  |
|            |         |      | ewater, |          |                  |
|            |         |      | and     |          |                  |
|            |         |      | con     |          |                  |
|            |         |      | trolled |          |                  |
|            |         |      | envir   |          |                  |
|            |         |      | onments |          |                  |
+------------+---------+------+---------+----------+------------------+
| [Phytoreme | Tec     | \$16 | Cost    | Plants   | Best used for    |
| diation]{. | hniques | ,700 | eff     | grow     | sites with low   |
| underline} | using   |      | ective, | slowly,  | to medium levels |
|            | plants  | /AC  | less    | results  | of contamination |
|            | to      |      | in      | take a   |                  |
|            | remove  |      | trusive | while,   |                  |
|            | Hg from |      | than    | Hg       |                  |
|            | the     |      | other   | captured |                  |
|            | envi    |      | m       | in plant |                  |
|            | ronment |      | ethods, | may be   |                  |
|            | or      |      | po      | a        |                  |
|            | immob   |      | llution | vailable |                  |
|            | ilizing |      | c       | to       |                  |
|            | it      |      | aptured | wildlife |                  |
|            | within  |      | can be  | feeding, |                  |
|            | the     |      | r       | not well |                  |
|            | envi    |      | ecycled | tested   |                  |
|            | ronment |      | and     |          |                  |
|            |         |      | reused  |          |                  |
|            |         |      | instead |          |                  |
|            |         |      | of      |          |                  |
|            |         |      | mining  |          |                  |
|            |         |      | more    |          |                  |
+------------+---------+------+---------+----------+------------------+
| Water      | Mani    | C    | Cost    | Manip    | Most easily      |
| quality    | pulates | ost: | eff     | ulations | implemented by   |
| management | water   | va   | ective, | need to  | current water    |
|            | quality | ries | less    | be       | managing         |
|            | such as |      | int     | mo       | agencies         |
|            | oxygen  |      | rusive, | nitored; |                  |
|            | content |      | and not | also may |                  |
|            | or pH   |      | a       | disrupt  |                  |
|            | to      |      | highly  | some     |                  |
|            | prevent |      | te      | e        |                  |
|            | MeHg    |      | chnical | cosystem |                  |
|            |         |      | te      | fun      |                  |
|            |         |      | chnique | ctioning |                  |
+------------+---------+------+---------+----------+------------------+

Boston Mine Preliminary Remediation Plan

The following is a description of a proposed project at the Boston Mine
near Nevada City, Calif. (Lawler, 2001). The Boston Hydraulic Mine is a
40-acre mine site containing significant concentrations of elemental and
methyl mercury in sediments located on the floor of a 200-foot sluice
box. Several remediation proposals have been suggested by the members of
the Bear-Yuba Technical Group for effective cleanup of mercury
contamination at the hydraulic mine sluice tunnel and hydraulic mine
ponds. The proposed Boston Mine Remediation Project is expected to
require 2--3 years for successful completion. Suggested remediation
techniques include the following:

-   [Sediment Removal Method (\$156,000)]{.underline}

> Sediments are removed from the floor and sides of the sluice tunnel,
> initially by mechanized equipment, and subsequently by manual methods.
> The operation is started at the upstream end of the tunnel so that the
> tunnel floor is not recontaminated downstream.

-   [Bat-Gate Installation on tunnel portals (\$20,800)]{.underline}

> Mine gates could prevent ongoing access into the tunnel by the general
> public. Public access into the tunnels can create mercury discharges
> as the tunnel sediments are disturbed by prospecting activities or by
> sightseers walking through the tunnel. This method should be regarded
> as an important first step in the mine tunnel remediation process.
> This will allow ample time for detailed site characterization and
> detailed sampling. (Lawler, 2001)

Contact: Dave Lawler (BLM) (<dlawler@ca.blm.gov>)

# IV. Mercury Reduction Programs And Techniques

Several techniques exist or are currently being developed for the
remediation of mercury and other contaminants. Techniques and
technologies include: excavation and treatment (physical separation,
thermal treatment, hydrometallurgical treatments), in situ recovery
(soil vapour extraction, permeable reactive walls, leaching and
extraction, phytoremediation,), and containment (pump-and-treat,
stabilization and solidification, sediment capping) (Hinton and Viega,
2001). Mercury reduction programs are also used to reduce this risk.
Programs include mercury collection and hazardous waste disposal,
restriction of sales of mercury-containing products, reduction of dental
waste mercury, and mercury recycling (CVRWQCB, 2001). The following
section summarizes the research literature on mercury reduction programs
and mercury remediation techniques. Each technique is described, and
cost estimates are listed if they are given.

## A. Mercury Remediation Techniques and Technologies 

The first remediation technology described is an ongoing research
project studying the use of [encapsulation]{.underline} to treat acid
mine drainage (AMD). Dr. Manoranjan Misra, University of Nevada at Reno,
has been conducting this research. The cement binder used in
encapsulation costs about \$12.90--16.10/ton of rock using 5--10 percent
by weight cement binder. The amount of binder depends upon the type of
acid tailings (Bortolin, 1999).

[Living island]{.underline} technologies would remove mercury from water
systems through certain plants using solar energy. A small island
ecosystem floats atop contaminated water bodies while hydrologic
conditions move the water through step-by-step cleanup. Costs are site
specific, since size, geology, and mercury concentrations vary. Costs
for a proposed 1-year pilot project on Lake Englebright ranged between
\$3.37 and 5.87 million. However, no such project was ever undertaken
(Lunceford, 2001).

[Passivation]{.underline} coats tailings with an impermeable coating
that prevents mercury from further chemical decomposition. Passivation
technology is based on the concept that "reactive rock can be unreactive
by covering the reactive rock with a strong and stable coating"
(Bortolin, 1999). Onsite equipment eliminates the need to export
contaminated material or pay for recycling costs. Costs of passivation
for a 65-acre site excavated to 1 foot in depth range between \$239,654
and \$288,370, or 32--54 cents a ton (Bortolin, 1999).

[Soil Washing]{.underline} is an *ex situ* soil remediation technique
combining aqueous removal and contaminant separation to lower the
remaining contaminant concentration in treated soil to specified levels.
Soil washing includes physical separation techniques and extraction
techniques, such as chemical leaching and attrition scrubbing. The EPA's
National Risk Management Research Laboratory wrote a report entitled
"Contaminants and Remedial Options at Selected Metal-Contaminated Sites"
that documents soil-washing costs (table 5).

Table 5. Soil washing unit costs (after EPA, 1995)

  ---------------- ------------------ ------------ ------------ ------------- -------------
                                      **Volume                                
                                      (short                                  
                                      tons)**                                 

  **Cost item**                       **25,000**   **50,000**   **100,000**   **200,000**

  Depreciation                        45.8         43.4         17.2          13.7

  Mobilization and                    9.2          4.6          3.4           1.1
  demobilization                                                              

  "Normal" site                       13.7         6.9          4.6           2.3
  preparation                                                                 

  Materials                           17.2         18.3         17.2          17.2
  handling                                                                    

  Labor                               34.4         28.6         22.9          17.2

  Chemicals                           17.2         17.2         17.2          17.2

  Maintenance                         9.2          6.9          4.6           2.3

  Safety equipment                    3.4          3.4          3.4           3.4

  Utilities                           9.2          9.2          9.2           9.2

  Process treating                    17.2         13.7         9.2           5.7

  Disposal of                         36.7         36.7         36.7          36.7
  residues                                                                    

  Management,                         80.2         68.8         55.8          45.8
  overhead, profit                                                            

  Net price                           293.4        237.9        201.4         171.8
  (\$/short ton)                                                              
  ---------------- ------------------ ------------ ------------ ------------- -------------

**Mercury Transportable Stabilization System**

The Mercury Transportable Stabilization System (MTSS), tested by Applied
Technology Group (ATG), treats contaminated water. Operating costs are
approximately \$102/hr (costs include two laborers, health and safety
oversight, and management support) (U.S. DOE, 1999). Reagent and
material costs, based on the nature of the waste, are expected to range
from \$54/ton for a dry, easily stabilized waste to \$969/ton for a
mostly liquid waste (U.S. DOE, 1999). The life-cycle unit cost is
estimated to be \$1.86/kg at a steady state 1,200 lb per hour processing
rate which increases to \$3.96/kg when processing at the lower end of
the rate range (100 lb/hour) (U.S. DOE, 1999). At Portmouth's DOE
facility in Ohio, ATG tested the application of stabilization of
low-level mercury in radioactive wastes. Projected costs for a 1,200
lb/hour stabilization system included capital costs of \$31,836 and
operating costs of \$101/hour. Unit costs were projected at \$1.84/kg
(FRTR, 2000). However, the actual costs will vary depending upon the
type and homogeneity of the waste, the nature of the matrix being
processed, and the presence of other hazardous constituents (U.S. DOE,
1999)

### **Sorbents**

Numerous sorbents have been developed for the removal of mercury and
heavy metals from watersheds. The following sorbents were tested to
remove mercury from microgram-per-liter levels to low nanogram-per-liter
levels (Bostick and Klasson, 1998). Table 6 summarizes various sorbents
and their costs.

Table 6. Types and costs of various mercury-reducing sorbents (Bostick
and Klasson, 1998)

  ----------------- ----------------- ------------------------ -----------
  **Sorbent type**  **Description**   **Recommended            **Cost
                                      conditions**             (\$)**

  Ionac SR--3       Binds ionic Hg,   Performs best at pH      12/liter
                    MeHg, and         values between 0 and 6   
                    elemental Hg                               

  Ionac SR--4       Weakly acidic     pH values ranging from 1 14/liter
                    resin             to 14; flow rate of 0.3  
                                      BV/min                   

  Keyle--X          Sulfur-based      Operates at high flow    126/liter
                    functional        rates; pre-treat with    
                    groups;           chlorine to 1--2 mg/l    
                    Hg-specific resin                          

  Mersorb L, 3, 1.5 Commercial        Sorption dependent on    5/liter
  mm                carbons           precipitation of the     
                    impregnated with  sulfide                  
                    sulfur                                     

  Forager sponge    Description below Pretreated with acid or  5/liter
                                      base                     
  ----------------- ----------------- ------------------------ -----------

The forager sponge (FS), an *in situ* technique for mercury removal, was
developed by Dr. Norman Rainer, of Dynaphore, Inc. When fully saturated
with mercury, the FS is usually sent to an incineration facility for
destruction of the sponge and recovery of the mercury. The FS is
composed of little \"sponge\" cubes that clean up polluted water by
absorbing the trace toxic organic and inorganic pollutants in it
(Dynaphore, 2002). It is a very effective system that will remove most
trace contaminants and can be used anywhere there is polluted water.
Table 7 compares the actual use cost of the forager sponge with its most
common competitors: beaded ion exchange resin and sulfur-treated
activated carbon. In this example, calculations were based on using FS
Type M-TU to remove mercury at a 0.2 ppb level (NCER, 2001).

Table 7. Forager sponge compared with other treatments (Dynaphore, 2002)

  ------------------- ---------------- ---------------- -------------------
  Absorbent           Forager          Ion exchange     Activated carbon

  Material cost       \$20/kg          \$42/kg          \$1.78/kg

  Hg loading @ 0.2    35 g/kg          6.5 g/kg         0.75 g/kg
  ppb                                                   

  Quantity needed to  29 kg            154 kg           1,333 kg
  remove 1 kg of Hg                                     

  Waste disposal      \$310            \$489            \$6,270
  costs per kg Hg @                                     
  \$60/cu ft                                            

  Cost to remove 1 kg \$890            \$6,960          \$8,643
  ------------------- ---------------- ---------------- -------------------

### **Amalgamation of Mercury-Contaminated Waste Using NFS DeHg Process**

ATG also tested the application of amalgamation of elemental mercury
(test locations were in Idaho and Tennessee). This process stabilizes
elemental mercury and uses a proprietary reagent to break mercury
complexes, and filtrate is either recycled to the reactor or discharged.
Assuming the waste is elemental mercury, projected costs for treating
more than 1,500 kg were \$323/kg, which does not include disposal costs
of the treated wastes (FRTR, 2000). Results showed that the process
reduced the concentration of mercury to 0.05 mg/L on average (FRTR,
2000). The Colorado Minerals Research Institute performed a similar
test, amalgamation of mercury-contaminated waste, and came to the same
cost conclusion (U.S. DOE, 1999). This process reduced the free mercury
by 99.87 percent to 99.98 percent (FRTR, 2000).

### **Polymer Filtration Technology for Removal and Stabilization of Mercury**

The Los Alamos National Laboratory developed a process for washing and
leaching elemental and ionic forms of mercury from solid debris for both
high and low concentrations (\>260 ppm and \<260 ppm, respectively)"
(Smith, 2002). The process includes using a leaching solution and
multiple ultra filtration applications. Costs depend on the weight of
the debris. During this treatability study, throughput could be 2.5
tons/yr of light debris or 50 tons/yr of heavy debris (Smith, 2002).
Costs in this study included equipment costs (\$40,800), energy costs
(\$0.055/kWh­­­), or about \$898/yr, ranging from \$412.90/ton for light
debris to \$21.54/ton for heavy debris. Chemical costs using reagents
from Fisher Scientific or Aldrich Chemical would cost \$876/ton for
light debris and \$318/ton for heavy debris with no polymer regeneration
(Smith, 2002). Additional cost estimates for projected cleanups are also
mentioned in the report.

**Sulfate Reducers**

L. Michael Saunders, Georgia Tech University, has been involved in
research focusing on the role of sulfate-reducing bacteria (SRB) in the
production of Methyl-Hg in marine systems. Saunders explains that in an
ideal system, we would want to shut sulfate reducers down, but they are
the dominant microbes. In addition, it is the natural cycling of carbon
in water systems that dictates their presence in the system and the
methylation processes they propagate on uncontaminated sediments (that
is, natural soils that contain Hg), as well as contaminated ones (L.
Michael Saunders, written commun., 2003). His research includes modeling
these processes to predict the impacts of a microbial community on
methyl-Hg production and impacts. Given the high level of carbon input
through natural processes, these methylation processes are very
difficult to stop or attenuate in marine systems (L. Michael Saunders,
written commun., 2003).

#  {#section-12}

## B. Mercury Recycling Programs

In recycling programs, mercury is recovered and collected by
participants, primarily recreational and commercial gold dredgers, in
the field and sold to commercial recycling operations at market value.
Recycling rarely involves the direct removal of mercury from the
watershed. On the other hand, it does prevent mercury from entering the
watershed by collecting mercury that might be used in mining activities
(by recreational miners) or that might be disposed of improperly. There
have been several different recycling programs. The first collection
effort in the Nevada County region in 2000 cost \$1,248 and gathered 220
lb of mercury from people's garages. Tracy Gidel (Nevada County
Environmental Health) said that Nevada County spent nearly \$102 to
recycle the last 15 lb they collected in 2001. A total of 315 lb has
been collected during the 2-year program (Lunceford, 2001). In 2001,
Rick Weaver, USFS, collected mercury from people's garages and shipped
it to a recycling center. The flasks cost \$260 each, and removal costs
were \$126 (Bethlehem Apparatus Company, Inc.). Table 8 provides an
example of recycling costs.

Table 8. Recycling costs (Lunceford, 2001)

  -------------------- ------------------------------ ----------------------
  **Shipping and                                      **2003 costs**
  handling costs**                                    

  West Sacramento      200--300 lbs                   \$362--\$786

                       Flasks (\$260 X 2)             \$520

                       Processing                     \$126

                       Total:                         \$1,008--1,432

  **Total recycling                                   
  costs for 2003**                                    

  Agency labor         (Reduced from 2000 figures by  \$9,010
                       45% + 5 hours County           
                       Personnel + truck rental       

  Contractor costs                                    \$102

  Container                                           \$520
  acquisition                                         

  Shipping and                                        \$1,008--1,432
  handling                                            

                       **Total recycling costs**      **\$10,640--11,064**
  -------------------- ------------------------------ ----------------------

Rick Humphreys (SWRCB) summarizes the efforts of the Sacramento River
watershed recycling efforts. The program targeted recreational gold
miners as a source of potential Hg, but little Hg was recovered from
this group. Most of the mercury recovered came from past mining
activities (Hg purchased for use in mining and then never used) and had
been stored for a long time in peoples' homes (Rick Humpreys, oral
commun., 2003). Other sources included laboratories and dental offices.
The program had the best success with older people (65+ yrs old) or
their heirs. Two individuals contributed 250 lb of mercury, but most
people contributed less than 1 lb. Humphreys estimated it cost agencies
\$16,272 in labor to set up the recycling program in the Sacramento
River watershed (Lunceford, 2001).

**Palo Alto**

Palo Alto's mercury collection program has been successful in
mercury-containing items, including thermometers, thermostats, and
fluorescent lamps. As of December 31, 2002, the program had collected
nearly 73 lb of mercury, including 1,784 thermometers, 44 thermostats,
and 4,310 fluorescent lamps (Weiss, 2003).

Table 9. Fluorescent lamp recycling costs (Weiss, 2003)

  ----------------------------------------------------- -----------------
  Total lights collected                                4,310

  Total lamp recycling costs                            \$1520.14

  Total shipping/startup costs                          \$676.00

  Total program operation costs                         \$2196.14

  Average cost per light to recycle                     \$0.51
  ----------------------------------------------------- -----------------

##### **U.S. Army Environmental Center**

Recycling costs for fluorescent lamps are often measured on a
linear-foot basis. The average cost is \$0.10/linear foot. Costs to
recycle high-density lamps range from \$1.25 to 4.50, with an average
cost of \$2.50 (U.S. Army Environmental Center, 1997).

**NY--NJ Port Authority/La Guardia Airport**

The NY--NJ Port Authority/La Guardia Airport did a cost-benefit analysis
(CBA) of recycling vs. disposal of mercury and found that they saved
\~\$5,000 in 2 years by recycling rather than disposing of mercury (NYC
Wasteless, 2001). Recycling costs include a recycling drum costing \$23
each and actual recycling costing \$64/drum. Disposal costs include \$43
for the drum and \$1,100/drum for the disposal (disposal drum holds
about 7--8 times as many lamps).

## C. Mercury Reduction Programs and Studies

**Brookhaven National Laboratory Study**

Various mercury treatment technologies were reviewed to determine the
most viable alternative to treat mercury-contaminated soil at Brookhaven
National Laboratory (BNL) (Boyce and others, 1999). BNL is a 5, 265-acre
site located in central eastern Long Island, N.Y. The facility is a
federally funded international research and learning center managed by
Brookhaven Science Associates.

The site has been on EPA's NPL since December 21, 1989. Technologies
that were reviewed include acid leaching, amalgamation, soil washing,
retorting, and stabilization (Table 10). Alternatives were based on
cost, treatment efficiency, availability, process operating parameters,
and the potential for the generation of secondary waste streams. The
contaminated material is classified as regulated hazardous waste low
mercury (that is, total mercury concentration \<260 mg/kg (ppm). The
soil is required to become nonhazardous (mercury concentration reduced
to \<0.2 mg/l) before final disposal (Boyce and others, 1999). According
to the RWQCB, the total threshold limit concentration (TTLC) for mercury
is 20 mg/kg (ppm) and the soluble TLC is 0.2 mg/l. Mercury
concentrations above these levels are considered hazardous (Michelle
Wood, CVRWQCB, written commun., 2003).

Table 10. Treatment alternatives from Brookhaven National Laboratory
Study (Boyce and others, 1999)

  ---------------- ----------- -------------- ------------ ----------- --------------------
  **Technology**   **Process   **Treatment    **Process    **Onsite or **Unit cost
                   rate**      efficiency**   duration**   offsite**   (\$/ton)**

  Acid leaching    6--8        \< 0.2 mg/l    1 hr         Off         485--2,154
                   tons/hr                                             

  Amalgamation     100 lbs/day \< 0.2 mg/l    4 hrs        Off         N/A

  Soil washing     200         \< 0.2 mg/l    N/A          On & Off    162
                   tons/day                                            

  Retorting        3--12       \< 0.2 mg/l    4--6 hrs     On & Off    539--2,154
                   tons/day                                            

  Stabilization    40 tons/day \< 0.2 mg/l    N/A          On & Off    43--2,154
  ---------------- ----------- -------------- ------------ ----------- --------------------

Conclusions from this study include the following:

-   Stabilization was found to be the most preferred alternative because
    of the relatively low cost, the treatment efficiency, and low
    likelihood for the production of significant secondary waste
    streams.

-   Soil--washing ranked high because of its low cost and high
    processing rate; however, it most likely requires a secondary
    treatment for the condensed mercury waste volume.

-   Retorting is not recommended as the best treatment alternative
    because of its high cost and the possibility of having to amalgamate
    the recovered mercury.

-   Acid leaching is not preferred because of the potentially large
    secondary waste streams, high cost, and availability.

> (Boyce and others, 1999)

**Dental Programs**

Dentists are the third largest users of mercury in the United States. In
2001, dentists used 40 metric tons of mercury (20 percent of the total
amount used in that year), most of which was released to the environment
(Bender, 2002). It is relatively inexpensive (\<\$50/month) for dentists
to remove and recycle mercury from their offices (Bender, 2002). The
Bender (2002) report recommends (in part) the following steps:

1.  The release of dental amalgam into waste streams should be
    prohibited. All mercury should be trapped, collected, and recycled.

2.  This should be fostered through voluntary incentives, technical
    assistance, and mandates to encourage and/or require dentists to
    follow best management practices, install amalgam separators, clean
    and replace mercury-contaminated pipes and plumbing, manage excess
    mercury, and submit annual reports on their reduction initiatives.

3.  The dental amalgam separators can reduce mercury discharge by 95
    percent or more.

Bender (on the basis of references in the report) further reports that
coarse, chair- side traps can collect \~60 percent of all amalgam waste,
and 95 percent or more can be captured when an amalgam separator is
added to the system. The cost of operating an amalgam separator ranges
from \$47.95 to \$100/month (Bender, 2002). The following table (table
11) illustrates mercury remediation technologies used by dentists and
their costs, taken from a report documented specifically for the State
of Minnesota.

Table 11. Estimated effectiveness of amalgamation activities (Minnesota
Pollution Control Agency, 2000)

  -------------- ------------ --------------- --------------- ---------------
  Recycling      Mass of      Estimated       Estimated cost  Estimated cost
  activity       recycled Hg  captured pounds per dentist     per pound of Hg
                              of Hg in Minn.  (\$)            removed (\$)

  Chair-side     0.6--1.2     586--1172       6.4--12.7       26.5
  traps                                                       

  Vacuum-pump    0.25--0.50   258--516        19.1--37.1      371--743
  traps                                                       

  Wastewater     0.05--0.25   52--258         53--159         478--72,374
  settable                                                    
  particles                                                   

  Wastewater     0.005        5.2             1,592           723,739
  soluble                                                     
  particles                                                   
  -------------- ------------ --------------- --------------- ---------------

Table 10 demonstrates the potential escalating cost impact to dentistry
and the dental public at each higher level of amalgamation waste
removal. Equipment costs vary as well. Options for low-cost systems
range from a simple sedimentation tank produced for as little as
\$53--318 to high-end equipment, such as centrifuges, costing as much as
\$3,184. Among commercial vendors, one complete capture system is
marketed for an installed cost of \$2,011, with an annual service fee of
\$345--403. A service claiming the capability to provide below-detection
discharge (200 parts per trillion) that includes full service waste
management is currently marketed for about \$1,592 per year.

Manufacturers' claims of 90--99 percent removal rates remain largely
unsubstantiated by published data, thus making accurate
cost-effectiveness comparisons impossible (Minnesota Pollution Control
Agency, 2000). The agency report suggests that before acceptance of any
systems for general use evaluation procedures should be performed to
assess effectiveness, efficiency, practicality, dependability, and final
destination of removed wastes, as well as relative costs.

**EIP Associates Study**

EIP performed a qualitative cost-effectiveness analysis of several
potential mercury reduction programs (Johnson, 2000). In the analysis,
the cost-effectiveness of each program was determined by evaluating the
potential quantity of mercury removed versus the potential cost of the
program. They report that the best opportunities for cost-effective
mercury reduction programs might focus on education/outreach for dental
offices, voluntary audits at dental offices, and bans on mercury
thermometer sales.

Other cost-effective opportunities for mercury reduction are as follows:

-   Education/outreach for hospitals, medical offices, laboratories, and
    the general public

-   Voluntary audits at hospitals and medical offices

-   Plumbing/trap cleaning at hospitals, medical offices, dental
    offices, laboratories, and educational institutions

-   Bulk mercury collection for dental offices and for the general
    public

-   Installation of amalgam separators at dental offices

-   Mercury thermometer take-back

-   Legislative lobbying and lobbying of professional organizations

-   Fluorescent bulb collection

-   Promotion of city policies to reduce mercury

**Ross and Associates Report**

In the draft report on mercury reduction options, various options are
evaluated for their cost effectiveness as measured in dollars/lb. Among
the lower cost strategies, the most cost effective appears to be the
collection of raw mercury (\$10/lb), reducing Hg use in consumer
products (\$10-100/lb), and the purchase and use of lower Hg containing
products (\$10-100/lb). Among the medium cost options, laboratory
pollution prevention (\$700-6,600/lb), enhanced air pollution control
(\$3,400-7,600/lb), and scrubber water treatment (\$2,000-20,000/lb)
were deemed most cost effective. For the higher cost options, carbon
injection at 60 percent overall Hg collection efficiency
(\$11,000-300,000/lb), lower exhaust temperature (\$100,000-125,000/lb),
and carbon injection at 30 percent overall Hg collection efficiency
(\$37,000-200,000/lb) are most cost effective. The least cost effective
option (by far) is to use the best available control technology to
capture Hg in WWTP water discharge (\$5,500,000/lb). The report
concludes that laboratory pollution prevention offers the greatest
reduction potential (20,394 lb/yr) (Ross and Associates, 2000).

## D. Sediment Control and Disposal 

Reductions in the total amount of mercury-laden sediment will increase
the chance of reducing the total amount of mercury available for
bioaccumulation. Various measures of erosion control and sediment
management options provide another remedial possibility to either
prevent contaminated sediment from reaching watersheds or remove
existing contaminated sediments. These sediment management options
include the following:

1.  *Stream channel dredging*: removal and disposal of instream
    sediments and associated mercury from historical hydraulic mining
    activity

2.  *Reservoir dredging*: removal and disposal of sediments and
    associated mercury deposited in study area reservoirs

3.  *Reservoir operational changes*: modifying the operation of major
    reservoirs to maximize the deposition of sediment and associated
    mercury from the water column

> (Weiner and others, 2003)

The EPA prepared a report by the Engineering and Technology Work Group
as part of the Assessment and Remediation of Contaminated Sediments
Program illustrating some of the costs of treating and disposing of
contaminated sediments. These contaminated sediments are not necessarily
contaminated with mercury but can be used as a reference for similar
projects. This report gives additional unit-cost figures for various
transport mediums of selected dredged material volumes (EPA, 1994).
Furthermore, this report documents unit costs for disposal technologies
and gives information on references for cost data (Table 12).

Table 12. Sources of information for cost data

(EPA, 1994)

  -------------------------- --------------------------------------------
  Source                     Type of information

  R.S. means cost data       Unit costs for various construction
                             activities

  Dodge guide                Unit costs for various construction
                             activities

  Corps unit price books     Unit costs for various construction
                             activities

  Marshall Stevens Index     Treatment plant and equipment costs and
                             index

  Chemical engineering       Treatment plant and equipment costs

  Engineering news record    Construction cost index for updating capital
                             costs

  Civil works construction   Regional adjustment factors for construction
  cost index system          costs

  U.S. Dept. of Energy       Energy costs, regional differences

  U.S. Dept. of Labor        Labor costs, regional differences

  Federal Emergency Admin.   Relocation costs
  -------------------------- --------------------------------------------

#  {#section-13}

## E. Ecosystem Restoration 

Mercury remediation projects can also target those variables that reduce
health risks caused by mercury contamination. Methyl mercury is a highly
toxic form that readily accumulates in exposed organisms and
biomagnifies to higher concentrations in commercial fish, causing
adverse health effects when consumed by humans (Weiner and others,
2003).

The physical and chemical factors contributing to the production and
breakdown of methyl mercury should be the focus of ecosystem restoration
activities. Wetland restoration, restoration of seasonal floodplains,
channel reconstruction, and dam removal are examples of restoration
activities considered most likely to affect mercury cycling and methyl
mercury exposure (Weiner and others, 2003). However, the relative
influence of many of the variables (for instance, habitat type,
temperature, water chemistry, and so on) on the production and
bioaccumulation of methyl mercury remains poorly quantified. Wetlands
and other ecosystem projects have the potential to both help and hinder
water quality problems. Therefore, very few restoration projects have
been undertaken solely to reduce methylation.

The following section briefly explores remediation and research
activities regarding ecosystem modifications and mercury. Although there
are very few restoration projects and technologies specifically
pertaining to mercury remediation, the following information presents an
overview of restoration dealing with metals. The RWQCB staff and other
agencies will explore this effort much further in the future.

### **Wetland/Marsh Research Projects and Technologies**

The Savannah River site, based in South Carolina, designed and built a
constructed wetland to treat a particular waste stream for copper and
its subsequent toxicity (Sarah Harmon, written commun., 2002). After
construction of the wetland was completed, it was discovered that the
waste stream might also be in violation of mercury limits. A series of
pilot-scale studies on the issue of mercury behavior were conducted in
this constructed wetland environment. Very low levels of mercury (ppb
levels) were found in this case. The pilot wetlands, on average,
decreased total mercury concentrations in the outfall stream by 50
percent (King and others, 2001). Mercury efficiency has improved with
maturation of the treatment cells within the wetland (Nelson and others,
2002). Since the vegetation has matured, researchers have seen 80
percent removal levels of mercury coming into the wetland system (Eric
Nelson, written commun., 2003).

Transformation of mercury to methyl mercury was also observed in the
wetland treatment system, showing a seasonal trend and being negligible
during the summer months (generally less than 1 ng/L in the effluent).
The facility was built for less than \$5 million, but costs are very
difficult to specify because this is a U.S. Federal facility and is hard
to relate to the commercial world. In addition, construction, operation,
and maintenance costs are minimal since the system is entirely passive
and only requires periodic observation (Nelson, written commun., 2003).
Constructed wetland technologies represent a feasible cost-effective
means of removing low levels of mercury compared with more expensive
treatment options, such as ion exchange (King and others, 2001).

Another research project based in the Savannah River area studied the
mercury geochemistry in wetlands and its implications for *in situ*
remediation. Results indicated that in ecologically sensitive wetlands,
traditional intrusive engineering approaches are not viable remediation
options (Kaplan and others, 2002). If mercury is too strongly bound to
sediments to permit plants to mine it out of the ground, then
phytoremediation is not the best option. In addition, if mercury was not
concentrated in the smaller particles, soil washing would be very
intrusive and not very effective. If either of these conditions occurs,
the best option would be monitored natural attenuation (Kaplan and
others, 2002). This approach consists of monitoring for mercury movement
in the aqueous phase.

Researchers funded by the EPA Hazardous Substance Research Center
examined the roles of certain microbe populations in mercury methylation
processes in the bioremediation of contaminated sediments in salt--marsh
systems. An assay tool and model to predict the impacts of a microbial
community on methyl-Hg production has been developed (L. Michael
Saunders, written commun., 2003). These processes are difficult to stop
or attenuate in marine systems with high levels of carbon input through
natural processes (L. Michael Saunders, written commun., 2003).

An additional project has been evaluating the availability of Hg, methyl
Hg, and selenium (Se) +4 and +5 in sediment from a lagoon that is
proposed for use in a wetland- creation project (Jack Word, written
commun., 2003). The biological tests that were performed include
toxicity testing with sediment and sediment elutriates (total Hg and
methyl Hg and total Se and +4 and +5 in each media), bioaccumulation
into the tissues of invertebrates, and body burdens in plants at the
proposed mitigation site and from tissue of lagoon plants where the
sediment was obtained. Results showed that even in the presence of much
higher total Hg values, the lagoon sediment showed less methyl Hg, and
the Hg that was present was not bioaccumulated into tissues of the test
organisms. These chemicals were less mobile because the sediment from
the lagoon was anaerobic when collected, therefore allowing high levels
of total sulfides in the sediment to prevent Hg and Se from settling
into the water column or test organisms (Jack Word, written commun.,
2003).

Vic McFarland and others are researching the feasibility of using the
Hamilton Army Airfield Wetlands restoration site on San Pablo Bay as a
case study for developing methods of mitigating methyl mercury
production and mobilization in wetlands construction using dredged
sediments (McFarland and others, 2002). Thus far, they have monitored
total Hg and MeHg during a dry and a wet season at 60 sample sites
surrounding this research area site. The dry season work is completed,
and the wet season analyses of the same sites are being completed (Vic
McFarland, written commun., 2003). The third phase involves intensive
geochemical, microbial, plant, and invertebrate analyses and will test
sediment amendments for reducing mercury methylation relative to
demethylation rates and the effects of plant/microbial communities on
mercury methylation (Vic McFarland, written commun., 2003). Cost
estimates for wetland monitoring and restoration are provided in
appendix D.

In general, constructed wetlands usually cost approximately \$100,000
per acre, varying by \$50,000 over or under that estimate depending on
different physical, hydrological, and chemical characteristics of each
site (Matt Huddleston, ENTRIX, written commun., 2003). If existing clays
can be compacted sufficiently to protect ground water (assuming this is
a treatment wetland), then significant cost savings may be made.
Huddleston also claims that the cost of constructing a wetland for
mercury treatment would not be significantly greater than constructing
one for copper or zinc. The crucial step is to understand the
biogeochemical characteristics of a site and then design accordingly.

***Finally, in the mid-1990s, the RWQCB (Region 2) did sample mercury
concentrations in Suisun Bay and sloughs. No remediation at this site
has taken place. However, remediation has taken place at the Stege Marsh
that includes the Zeneca site and the UC Richmond field station in
Richmond (Karen Taberski, written communication., 2003).***

**CALFED Research Efforts**

In 1994, State and Federal agencies formed the CALFED Bay-Delta program
to respond to the growing number of environmental, water quality, and
water supply problems in the San Francisco Bay/Sacramento-San Joaquin
Delta. As of 2001, more than \$250 million of CALFED funds had been
spent on 170 ecosystem restoration projects that were underway or
completed (CALFED, 2002). These projects focus on wetland restoration,
the evaluation of heavy metals (including mercury) in water and fish,
habitat protection, and the control of invasive species.[^4]

As part of CALFED's strategy for studying mercury and its implications,
the CALFED Bay-Delta Agency granted funds in 1998 to the University of
California at Davis to study the effects of wetland restoration on the
production and bioaccumulation of methyl mercury in the Sacramento-San
Joaquin Delta watershed. This type of research is driven by the concern
that significant new wetland creation in the delta may increase MeHg
production, resulting in increased MeHg bioaccumulation in aquatic
organisms, as well as in their consumers. Methyl mercury/total mercury
ratios and sediment methyl mercury concentrations were found to be
"significantly greater in flooded tracts characterized by dense
submergent aquatic vegetation, as compared with adjacent Delta channel,
mudflat, or sand flat environments" (Slotton and others, 2002).

Heavily vegetated wetland tracts are areas of high total mercury,
enhanced methylation, and exporters of elevated MeHg concentrations
associated with reduced loads of particulates, yet they vary with
season, tract habitat, food web characteristics, and other factors.
Additional information on wetland projects throughout the San Francisco
Bay Area can be accessed through a map-based database:
[www.wetlandtracker.org](http://www.wetlandtracker.org/).

# V. Disclaimers On Remediation Cost Predictions

Remediation cost figures for modern mines, as well as other remediation
activities, are not well documented in the public record for several
reasons. These reasons may include the following:

-   Specific remedial actions taken must be reported to regulator
    agencies, but costs typically are not.

-   Some actions may be short-term measures while others are often
    complex, long--term solutions; therefore, cumulative cost data are
    not usually gathered correctly.

-   Costs are often considered proprietary to the mine operator.

> (EPA, 1997)

Therefore, forecasting costs for future mitigation decisions on the
basis of past projects and remedial actions may be poor at best. There
are some significant issues to consider in predicting unit costs for
future remediation projects using these past figures from previous
sites, mercury reduction programs, and technologies. Experts from the
geology and engineering fields describe some of the issues in making
predictions for cost estimates for future sites on the basis of past
projects.

Ron Churchill (California Department of Conservation, Division of Mines
and Geology), a geologist, explains some of these issues. According to
Churchill, mine remediation is site specific, and there is no such thing
as an average mercury or gold mine. California alone contains more than
600 mercury mines and prospects and more than 14,000 gold mines. On this
subject he writes:

-   Very similar mines with regard to mine size, history, and deposit
    type may require dramatically different reclamation activities
    because of geographic setting, and others will require no
    reclamation at all.

-   Some mercury and gold mines contain AMD problems, and others don\'t.

-   Attempting to recover mercury from a site where it is an issue
    isn\'t always the best approach. Isolation and containment on or
    near the mine site makes more sense from the scientific/engineering
    standpoint and monetarily.

-   Not all elevated mercury at a mercury mine site is present in waste
    rock piles, tailings piles, ore piles, or processing facilities, but
    mercury is elevated in local soil and rock at the mine site by
    entirely natural processes.

> (Ron Churchill, written commun., 2002)

Greg Reller (Tetra Tech), an engineer, has had experience with mercury
remediation projects and identifying unit costs. Greg comments:

> Mine costs do not translate readily to remediation technology costs in
> general or mine remediation technology specifically. To estimate
> remediation costs, engineers and scientists identify a technology
> (using experience, literature review, and input from others) then
> critically evaluate how it would work at the specific site of
> interest. After identifying the technology and figuring out how it
> would actually be applied to the site, they conceptually break down
> the technology into components (for example, design, mobilization,
> staging, preparation, construction, and restoration) and estimate the
> costs for each component. After a specific technology has been applied
> to several different sites, unit costs can be derived; however, these
> costs always must be considered in terms of how closely the site
> conditions match the conditions that were present when/where the unit
> costs were derived.
>
> For example, let's say we want to move 10,000 yd^3^ of soil and rock
> to a repository and cap it. In one location and for one set of
> chemicals, the cost may be on the order of \$25/yd^3^. At another
> location and for the same set of chemical conditions, the cost could
> be \$50/yd^3^ or more. Variables other than material characteristics
> (which are very significant) affect costs. Some of these variables
> include regulations applicable to the project, location, site access,
> and infrastructure. For these reasons, it may be difficult to try and
> compare costs directly on the basis of factors such as chemicals
> present, site geology, and so on.
>
> (Greg Reller, written commun., 2002).

Reller also describes how remediation techniques do not necessarily work
for all types of metals:

-   Remediation can be very specific to both metal present and each
    site. If acid drainage is the issue, then neutralization (say by
    adding lime in a contact tank) is effective for most metals.
    However, the contact time required to attain water quality standards
    will vary by metal.

-   Techniques that are great at one site for a metal may fail at
    another site with the same metal.

-   Varying chemical characteristics of metals dictate remediation
    decisions. Consideration of solubility curves for various metals
    (say solubility with pH) provide a partial answer to this question.

> (Greg Reller, written commun., 2002).

Forecasting predictions of future unit costs and total costs for mercury
remediation practices can be estimated on the basis of past mercury
projects and well understood engineering practices and techniques.
However, Reller says that an 'outcome prediction is usually subjective
and based on the degree to which the site is understood and a reputable
prediction would never claim absolute certainty. However, using prior
experience and the degree to which our data lead to an understanding of
the site, we can identify expected outcomes. Measurement of outcomes is
usually attained through direct monitoring' (Reller, 2002).

# VI. Remediation Process 

Detailed geologic site characterizations are required to provide
appropriate remediation measures, accurate cost estimates, and efficient
project implementation. The remediation of abandoned mine sites requires
much more time than typical geotechnical projects, such as time for
identifying and quantifying the mine-related environmental problem,
developing mitigation alternatives, undertaking legal action, securing
funding, and implementing remediation measures.

## A. Factors Affecting Remediation Decisions 

Numerous elements are used to evaluate the suitability of specific
remedial measures for a given site. The ability to predict contaminant
mobility and subsequently make mitigation decisions is based on
understanding the distribution and properties of soils, rock types, and
site hydrogeology and hydrology in conjunction with physiochemical
properties of the contaminant (Hinton and Viega, 2001). Such factors can
contribute to a preliminary assessment of risk to human health and
provide a basis for evaluating and then designing measures for
remediation.

Although numerical criteria developed by government officials are
valuable indicators of the occurrence and extent of contamination,
sometimes these levels are not economically or technically attainable.
More aggressive and costly measures may be warranted if Hg is detected
in biota or if the risk of its subsequent incorporation into organisms
is bioaccumulative, especially in localized areas. Responses may include
the implementation of consumption advisories, educational programs, and
technology modifications to lessen exposure to Hg vapor (Hinton and
Viega, 2001). Containment methods are sufficient if the potential for
assimilation into the food chain is low. In either situation, long-term
management is required until adequate protection of ecological and human
health is ensured.

An engineering approach, as described by Greg Reller, explains some of
the decisions that are made as part of the remediation process:

-   Site-characteristic features are identified by gathering enough
    information to understand how the site affects the environment and
    then comparing the information to the regulatory standards or
    criteria.

-   Such remediation measures are identified by considering what
    technologies have worked at similar sites in the past and by looking
    for creative or innovative technologies that may be effective at the
    site.

-   Benefits and drawbacks of each technology are then compared to
    arrive at a decision.

-   Total costs are based on the components of the remediation. These
    components include design, field engineering, construction
    management, mobilization, demobilization, site preparation, labor,
    materials, startup, and operations and maintenance.

Other categories and factors influencing remediation costs for mine
sites are listed in table 13. This list is not intended to be inclusive
(EPA, 1997).

Table 13. Factors influencing remediation costs at mine sites (EPA,
1997)

  ----------------------------------- -----------------------------------
  Category                            Factors

  Remediation goals                   Level of cleanup required

  Waste characterization sampling     Type and volume of material and
                                      waste, number and frequency of
                                      sampling events

  Water quality                       Degree of contamination: water and
                                      sediments

  Site characteristics                Size of operation, site access,
                                      climate, geologic materials,
                                      elevation, topography

  Liners                              Soil, clay, amended soil, synthetic

  Site hydrology                      Precipitation, flow rate, water
                                      controls

  Water treatment                     Type of treatment, volume,
                                      management of treatment residuals,
                                      length of time required

  Site operations                     Effect on production; time to
                                      achieve remediation goals; total
                                      ore and waste rock tonnage; extent
                                      of site impacts; earthwork
                                      requirements, labor, imported
                                      material

  Regulatory considerations           NPDES, CERCLA, dam safety
                                      requirements, local regulations

  Water-quality monitoring            Number of analyses, laboratory
                                      analysis, size of area to be
                                      monitored, number of sampling
                                      stations, ground-water monitoring

  Reclamation requirements            Area to be revegetated, type and
                                      amount of cover materials,
                                      feasibility and duration,
                                      post-reclamation land use
  ----------------------------------- -----------------------------------

As explained in the previous section, project costs are site specific
and based on parameters, such as the type of remediation technology
selected, the size of the affected area, the characteristics of the
contaminants, the required cleanup standards, the level of health and
safety protection required during the remediation, the type and number
of chemical analyses, and any long-term, postremedial actions required.
Any one of these factors can have a significant impact on the final cost
of remediation. Careful consideration of site-specific factors is
essential in achieving an accurate cost estimate (EPA, 1997). EPA's
Office of Solid Waste report, "Costs of Remediation at Mine Sites,"
summarizes different actions, costs, and mine remediation projects.
Additional unit cost estimates for waste-pile mine remediation are shown
in appendix E.

## B. Guidance to Documenting Costs for Remediation Projects

Some Federal documentation does exist that provides guidance for
engineering firms to predict remediation costs. For instance, an
interagency group consisting of the U.S. EPA, Department of Defense,
Department of Energy, and Department of the Interior developed a
standardized work breakdown structure (WBS) for remediation projects.
The use of the WBS "will facilitate comparison of costs across projects,
and the detailed breakout will help support extrapolation of costs to
future applications" (FRTR, 1998). Cost elements are grouped temporally:
before treatment (mobilization, preparatory work, site work, ground and
surface water collection), treatment (chemical, physical, biological,
thermal), and after treatment (disposal, restoration).

The WBS format uses data collected as part of Federal procurements for
site remediation services and stored electronically in a historical cost
analysis system. Other software packages that aid engineers include the
Remedial Action Cost Engineering and Requirements System prepared by
Delta Research Corporation and Cost of Remedial Action, a computer cost
program prepared by CH2M Hill. Some remedial action decision support
system packages are listed in table 14.

#  {#section-14}

Table 14. Remedial action decision support system packages (Sullivan and
others, 1997)

  ----------------------------------- -----------------------------------
  BIOSVE (Biodegradation, Spoil Vapor RAAS (Remedial Action Assessment
  Extraction and Vacuum Enhanced      System)
  Recovery                            

  CURE (Cost Uncertainty in           RACER (Remedial Action Cost
  Remediation Engineering)            Estimation

  MARS (Multiphase Area Remedy        SELECT (Remedy Selection)
  Selection)                          
  ----------------------------------- -----------------------------------

#  {#section-15}

# VII. Remediation Control Options And Strategies

Predicting remediation costs and contingency costs for various mercury
control operations is very difficult because of the site-specific nature
of mercury remediation.

However, mercury control strategy alternatives can be assessed through
different criteria to help decisionmakers choose the control option that
will give them the best opportunity to meet standards or objectives at
the lowest cost.

## A. Hydraulic Mine Site Strategies

This section will evaluate various remedies for hydraulic mine sites
that exhibit mercury contamination in soil, sediment, and surface water.
These remedies are explained in a report prepared for the USFS entitled
"Hydraulic Mine Site Mercury Contamination Site Characterizations and
Removal Action Considerations" (DeGraff, 2002). Although mine site
characteristics and operations vary, most sites have several features in
common: a pit lake, a pit wall, a wetland, a sluice cut, and drain
tunnels. The report describes each of these features in detail. Table 15
summarizes these characteristics and remedial options.

Table 15. Hydraulic mine site characteristics and remedial options (CDM,
2002)

+---------+------------------------------+-----------------------------+
| Feature | Characteristics              | Remedial options            |
+---------+------------------------------+-----------------------------+
| Pit     | Estimated volume of water to | Mechanical moving; suction  |
| lake    | be treated;                  | method;                     |
|         |                              |                             |
|         | total and MeHg               | capping; traditional        |
|         | concentrations;              | landfill design;            |
|         |                              |                             |
|         | other water-quality          | evapotranspiration cover;   |
|         | parameters; size             | so                          |
|         | distribution and depth of    | lidification/stabilization; |
|         | contaminated sediment;       | breaching wall; recontour   |
|         | topography; position of      | site                        |
|         | site; flow rate; drainage;   |                             |
|         | characterization of          |                             |
|         | subsurface/bedrock           |                             |
+---------+------------------------------+-----------------------------+
| Wetland | Regulatory consideration;    | Install French drain; fill  |
|         | size and area of wetland;    | wetland to match adjacent   |
|         | determination of             | contours; diversion surface |
|         | sources/pathways;            | channels                    |
|         |                              |                             |
|         | mercury levels in sediment   |                             |
+---------+------------------------------+-----------------------------+
| Pit     | Scale-height, width, volume  | Blasting; soil nailing;     |
| Wall    | of material at risk;         | retaining wall/sheet        |
|         | stability; pitwall           | piling/timber lagging       |
|         | structural composition;      |                             |
|         | determination whether Hg     |                             |
|         | contamination exists         |                             |
+---------+------------------------------+-----------------------------+
| \(A\)   | Depth, volume, and size      | \(A\) Daylight tunnel;      |
| Tunnel  | distribution of bottom       | mechanical removal;         |
| and     | sediments; condition of      | hydrowash; liner;           |
| Shafts; | bedrock forming floor and    | st                          |
|         | walls in tunnels;            | abilization/solidification; |
| \(B\)   |                              |                             |
| Surface | extent and level of Hg       | \(B\) mechanical moving;    |
| Sluice  | contamination in sediments;  | grout sediments in place;   |
| Cuts    | location and accessibility   | fill channels with          |
|         | of tunnels                   | soil/grout mixture;         |
|         |                              | diversion surface channels  |
+---------+------------------------------+-----------------------------+
| Other   | Role of site in drainage of  | Seal openings; breaching    |
|         | entire watershed             | mine pit;                   |
|         |                              |                             |
|         |                              | drill diversion tunnel;     |
|         |                              | pipelines                   |
+---------+------------------------------+-----------------------------+

There have also been emerging chemical and biological remedial
technologies for hydraulic mine sites. Chemical measures include using
iron oxides in laterite crusts to reduce the mobility of mercury in soil
by oxidizing the mercury, using commercial reagents for metal removal,
applying eletrokinetic remediation, using an electrical current in a
vitrification process to solidify/stabilize mercury, and implementing an
aeration system in anoxic areas that are hotspots for the mercury
methylation (CDM, 2002). Biological measures include phytoremediation,
phytoextraction, phytostabilization, and microbe usage. Appendix F
provides information on equipment needed for various remedial options,
along with unit costs.

## B. General Remediation Control Strategies 

Various remediation control strategies for mercury can be assessed using
several criteria, such as the accessibility of mercury contamination,
data efficiency, and the potential benefits and impacts of controls and
sources. As a result of declining budgets, the expected relative cost of
the mercury control strategy is important. Another important variable is
the degree to which the mercury is accessible for cleanup; that is,
whether the mercury is localized and concentrated or diffuse and widely
distributed. The quantity and quality of data are important in assessing
such situations. Expected benefits of implementing the control strategy
are important factors in choosing between various strategies as well.
Significant benefits include the estimated percentage of mercury loads
removed (or controlled) by source controls and significant increases in
beneficial uses.

In choosing a control strategy, one must also take into account the
potential environmental or economic impacts associated with the strategy
implementation. For example, LWA (1997) evaluated and developed
[subjective]{.underline} rankings of various remediation control
strategies. Table 16 is an example of control strategy evaluation
criteria.

Table 16.

Summary of control strategy evaluation criteria

+----------------+----------------+----------------+------------------+
|                | Control        |                |                  |
|                | strategies     |                |                  |
+----------------+----------------+----------------+------------------+
| Evaluation     | 1 (best)       | 2              | 3 (worst)        |
| criterion      |                |                |                  |
+----------------+----------------+----------------+------------------+
| \% of inplace  | \> 50%         | 25 - 50%       | 0%               |
| Hg sources     |                |                |                  |
| removed or     |                |                |                  |
| controlled     |                |                |                  |
+----------------+----------------+----------------+------------------+
| Are Hg source  | Existing       | Some           | Extensive        |
| data           | information is | additional     | additional data  |
| sufficient to  | sufficient     | data are       | needed           |
| implement      |                | needed         |                  |
| strategy?      |                |                |                  |
+----------------+----------------+----------------+------------------+
| Limitations of | Minor          | Moderate       | Severe           |
| strategy       |                |                |                  |
+----------------+----------------+----------------+------------------+
| Impacts:       | No significant | Potentially    | Severe           |
|                | impacts        | significant    | environmental or |
| Environmental  | expected       | impacts        | economic impacts |
| and economic   |                | expected       | expected         |
| impacts of     |                |                |                  |
| implementation |                |                |                  |
+----------------+----------------+----------------+------------------+
| Decrease in    | Significant    | Moderate       | No long-term     |
| study area Hg  | decrease in Hg | decrease in Hg | decrease in Hg   |
| loads and      |                |                | expected         |
| concentrations | (\> 25%)       | (\< 25%)       |                  |
+----------------+----------------+----------------+------------------+
| Relative cost  | [Low           | [Moderate      | [High            |
| per unit of Hg | cos            | cos            | c                |
| controlled     | t]{.underline} | t]{.underline} | ost]{.underline} |
|                |                |                |                  |
|                | per kg of Hg   | per kg of Hg   | per kg of Hg     |
|                | controlled     | controlled     | controlled       |
+----------------+----------------+----------------+------------------+

Control strategies reviewed in LWA's report include PS controls (water
treatment for mercury removal), mercury reduction programs (recycling),
various mine remediation strategies (stabilization and reclamation of
hydraulic mining tailings, removal of hydraulic mining tailings,
additional regulation of gold mining activity), and sediment management
(stream channel dredging, reservoir dredging, reservoir operational
changes). These strategies were evaluated using the criteria above and
then ranked. For the results of these rankings, please refer to LWA's
report. Additional criteria when estimating costs, such as human health,
risk, and methylation reduction are also important indicators when
assessing and implementing a remedial strategy.

## C. Remediation Cost Strategy

Most cost estimates that have been shown in this document have been from
engineers. Project costs are very site specific and are based on a
number of parameters, such as type of contaminant, type of remediation
technology selected, size of the affected area, characteristics of the
contaminants, required cleanup standards, and so on. Agencies use these
characteristics and break them down into different cost elements (FRTR,
1998).

Others use a methodology to estimate costs that relies on a variety of
cost worksheets under categories such as source control, active
treatment, passive treatment, general treatment and polishing, and
discharge methods (Tetra Tech, 2000). Costs are usually broken down into
capital (one-time costs occurring at the beginning of a project:
construction, equipment, and installation) and operating costs
(recurring costs; costs associated with doing the work necessary to
obtain required remediation levels, labor, and so on). Using these
worksheets, although used consistently throughout engineers' work lives,
is very time and resource intensive. Several software packages currently
in use are helping engineering companies estimate remediation costs (for
instance, the Remedial Action Cost Engineering and Requirements system).
However, the costs of these systems, the upfront costs of purchasing the
equipment, and the time and effort to estimate hundreds of various sites
may be too burdensome.

An econometric approach to estimate remediation costs is an alternative
solution in predicting remediation costs for mercury control. Since
there are hundreds of potential remedial solutions for mercury control,
some type of tool is needed that can easily predict an average cost
estimate with confidence for each of these potential controls. One
possible approach would be to create a multivariate regression model of
average or total costs that correlates with the physical and location
attributes of existing projects. A regression formulation would consist
of environmental (X~i~) and location attributes (X~j~), with a series of
fixed--effects variables for mine locations and attributes (D~m~)[^5]:

Total Costs = f (X~i~,X~j,~ D~m~)

The second step is to collect as much information as possible on current
mines and other possible remediation options (for instance, sediment
control, geothermal springs, wetland modification). Regression
coefficients can be estimated using these data. Cost estimates can be
based on these environmental and location attributes. The benefit of
using this tool is the ability to predict rough yet confident cost
approximations for specific locations without doing a complete
engineering analysis. Although this approach has some promise, there
have been doubts expressed by engineers who believe that projects are
much too site specific to establish such relationships. Such a tool
depends on the availability and accuracy of the data.

# VIII. Conclusion 

RWQCBs have the challenging task of developing TMDLs for numerous
watersheds. The complexity of mercury fate and transport, speciation,
and biological consequences does not make this job easier. Applying cost
estimates for mercury remediation projects complicates the situation
even further. However, compiling information on past, current, and
proposed projects reveals some insights into general categories of
remediation costs. Numerous mercury technologies, reduction programs,
and remediation techniques provide a clearer picture of the types of
activities that public or private entities can undertake to reduce the
risk of mercury contamination and the associated costs of these
activities. Gold and mercury mine remediation, mercury reduction
programs, sediment management, and ecosystem restoration projects are
all possible solutions with certain advantages and disadvantages.
Agencies have to decide which priorities are more important when
assessing a potential remediation project, area, technique, and
activity.

The purpose of this economic analysis was to show the general costs
associated with the various remedial practices that are applicable to
mercury sources in the delta and its tributary watersheds. The RWQCB
intends to use this information to determine the relative costs for mine
remediation projects and other mercury reduction programs.

# Appendices

## A: Estimated Cost for Final Compliance: Buena Vista Mine (after SECOR, 1999) 

+---------------+--------+-----------+-----------+--------+----------+
| Remediation   | Qu     | Total     | Price     | Unit   | Price    |
| action        | antity | cost (TC) | deflator  | cost   | deflator |
|               | and    | (\$)      | 2003 TC   | (UC)   | 2003 UC  |
|               | type   |           | (\$)      | (\$)   | (\$)     |
|               | of     |           |           |        |          |
|               | unit   |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Office-perm   | #  {   | #  {#se   | #  {#se   | #  {   | #  {#sec |
| itting/design | #secti | ction-17} | ction-18} | #secti | tion-20} |
|               | on-16} |           |           | on-19} |          |
+---------------+--------+-----------+-----------+--------+----------+
| Engineering   | 1 LS   | 40,000    | 43,084    | 40,000 | 43,084   |
| evaluation    |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Perm          | 1 LS   | 30,000    | 32,313    | 30,000 | 32,313   |
| itting/agency |        |           |           |        |          |
| c             |        |           |           |        |          |
| orrespondence |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Surveying     | 1 LS   | 15,000    | 16,157    | 15,000 | 16,157   |
+---------------+--------+-----------+-----------+--------+----------+
| Health and    | 1 LS   | 1,000     | 1,077     | 1,0000 | 1,077    |
| safety plan   |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Engineering   | 1 LS   | 50,000    | 53,855    | 50,000 | 53,855   |
| design        |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| *Subtotal*    |        | 136,000   | 146,486   |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Onsite        |        |           |           |        |          |
| engine        |        |           |           |        |          |
| ering/project |        |           |           |        |          |
| management    |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Prejob        | 1 LS   | 5,000     | 5,386     | 5,000  | 5,386    |
| meetings      |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Field         | 42     | 126,000   | 135,715   | 3,     | 3,213/wk |
| technician    | weeks  |           |           | 000/wk |          |
+---------------+--------+-----------+-----------+--------+----------+
| Project       | 22     | 88,000    | 94,785    | 4,     | 4,308/wk |
| management    | weeks  |           |           | 000/wk |          |
+---------------+--------+-----------+-----------+--------+----------+
| Project       | 42     | 105,000   | 113,095   | 2,     | 2,693/wk |
| control       | weeks  |           |           | 500/wk |          |
+---------------+--------+-----------+-----------+--------+----------+
| Field         | 42     | 10,500    | 11,309    | 250/wk | 269/wk   |
| equipment     | weeks  |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Photo         | 1 LS   | 500       | 539       | 500    | 539      |
| documentation |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| *Subtotal*    |        | 335,000   | 473,924   |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Site          |        |           |           |        |          |
| preparation   |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Mobilization  | 1 LS   | 50,000    | 53,855    | 50,000 | 53,855   |
+---------------+--------+-----------+-----------+--------+----------+
| Construction  | 80     | 80,000    | 86,168    | 1,000/ | 1        |
| staking and   | days   |           |           |        | ,077/day |
| field surveys |        |           |           | day    |          |
+---------------+--------+-----------+-----------+--------+----------+
| Road          | 1 LS   | 5,000     | 5,386     | 5,000  | 5,386    |
| improvements  |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Clear and     | 1 LS   | 20,000    | 21,542    | 20,000 | 21,542   |
| grub          |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Debris        | 1 LS   | 20,000    | 21,542    | 20,000 | 21,542   |
| removal       |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Storm water   | 1 LS   | 15,000    | 16,157    | 15,000 | 16,157   |
| diversion     |        |           |           |        |          |
| conduit and   |        |           |           |        |          |
| pump          |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Misc.         | 1 LS   | 25,000    | 26,928    | 25,000 | 26,928   |
| erosion;      |        |           |           |        |          |
| safety/fire   |        |           |           |        |          |
| controls      |        |           |           |        |          |
+---------------+--------+-----------+-----------+--------+----------+
| Subtotal      | #  {   | 215,000   | 231,578   | #  {   | #  {#sec |
|               | #secti |           |           | #secti | tion-23} |
|               | on-21} |           |           | on-22} |          |
+---------------+--------+-----------+-----------+--------+----------+

**Appendix---A continued**

+-----------------------+-------+---------+---------+-------+--------+
| Remediation action    | Qua   | Total   | Price   | Unit  | Price  |
|                       | ntity | cost    | d       | cost  | de     |
|                       | and   | (       | eflator | (UC)  | flator |
|                       | type  | TC)(\$) | 2003 TC | (\$)  | 2003   |
|                       | of    |         | (\$)    |       | UC     |
|                       | unit  |         |         |       | (\$)   |
+-----------------------+-------+---------+---------+-------+--------+
| *Ore excavation,      |       |         |         |       |        |
| segregation,          |       |         |         |       |        |
| trucking*             |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Excavation,           | 15    | 300,000 | 323,130 | 2.    | 2      |
| segregation,          | 0,000 |         |         | 00/CY | .15/CY |
| loading^5^            | CY    |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Trucking to           | 20    | 400,000 | 430,840 | 2.0   | 2.     |
| repository            | 0,000 |         |         | 0/ton | 15/ton |
|                       | tons  |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Ore dump              | 80    | 8,000   | 8,612   | 10    | 107.   |
| dewatering/treatment  | days  |         |         | 0/day | 65/day |
+-----------------------+-------+---------+---------+-------+--------+
| Dust control          | 170   | 85,000  | 91,554  | 50    | 5      |
|                       | days  |         |         | 0/day | 39/day |
+-----------------------+-------+---------+---------+-------+--------+
| Building demolition   | 1 LS  | 300,000 | 323,130 | 30    | 3      |
|                       |       |         |         | 0,000 | 23,130 |
+-----------------------+-------+---------+---------+-------+--------+
| Retort dump final     | 2,000 | 5,000   | 5,386   | 2.    | 2      |
| grading/topsoil       | CY    |         |         | 50/CY | .69/CY |
+-----------------------+-------+---------+---------+-------+--------+
| Verification soil     | 50    | 10,000  | 10,771  | 200/  | 215.42 |
| sampling^1^           | sa    |         |         |       | s      |
|                       | mples |         |         | s     | amples |
|                       |       |         |         | ample |        |
+-----------------------+-------+---------+---------+-------+--------+
| Placement and         | 15    | 450,000 | 484,695 | 3.    | 3      |
| compaction of ore     | 0,000 |         |         | 00/CY | .23/CY |
|                       | CY    |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Subtotal              |       | 1,      | 1,      |       |        |
|                       |       | 558,000 | 678,118 |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| *Repository           |       |         |         |       |        |
| construction/ore      |       |         |         |       |        |
| placement*            |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Repository earthwork  | 5     | 2       | 215,420 | 4.    | 4      |
|                       | 0,000 | 00,0000 |         | 00/CY | .31/CY |
|                       | CY    |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Repository liner      | 1 LS  | 275,000 | 296,203 | 27    | 2      |
| installation^2^       |       |         |         | 5,000 | 75,000 |
+-----------------------+-------+---------+---------+-------+--------+
| Leachate collection   | 1 LS  | 25,000  | 26,928  | 2     | 25,000 |
| system                |       |         |         | 5,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Geotextile/geonet     | 1 LS  | 130,000 | 140,023 | 130   | 1      |
|                       |       |         |         | ,0000 | 30,000 |
+-----------------------+-------+---------+---------+-------+--------+
| Protective soil cover | 1     | 40,000  | 43,084  | 2.    | 2      |
|                       | 6,000 |         |         | 50/CY | .69/CY |
|                       | CY    |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Onsite compacted      | 5,500 | 22,000  | 23,696  | 4.    | 4      |
| cohesive soil         | CY    |         |         | 00/CY | .31/CY |
+-----------------------+-------+---------+---------+-------+--------+
| Topsoil               | 5,500 | 13,750  | 14,810  | 2.    | 2      |
|                       | CY    |         |         | 50/CY | .69/CY |
+-----------------------+-------+---------+---------+-------+--------+
| Monitoring wells^3^   | 3     | 6,000   | 6,463   | 2,000 | 215    |
|                       | each  |         |         | /each | 4/each |
+-----------------------+-------+---------+---------+-------+--------+
| **Subtotal**          |       | 711,750 | 766,626 |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| *Erosion control of   |       |         |         |       |        |
| nonacid-generating    |       |         |         |       |        |
| soil*                 |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Grading/ore           | 10    | 400,000 | 430,840 | 4.    | 4      |
| segregation/b         | 0,000 |         |         | 00/CY | .31/CY |
| ackfill/compaction^4^ | CY    |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Sedimentation         | 1 LS  | 70,000  | 75,397  | 7     | 75,397 |
| basin^5^              |       |         |         | 0,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Cypress Road          | 1 LS  | 40,000  | 43,084  | 4     | 43,084 |
| diversion/culvert^6^  |       |         |         | 0,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Rock-lined conveyance | 1 LS  | 40,000  | 43,084  | 4     | 43,084 |
| channels              |       |         |         | 0,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Upper pit seed        | 1 LS  | 35,000  | 37,699  | 3     | 37,699 |
| pipe/culvert          |       |         |         | 5,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Subtotal              |       | 585,000 | 630,104 |       |        |
+-----------------------+-------+---------+---------+-------+--------+

+-----------------------+-------+---------+---------+-------+--------+
| *Passive AMD          |       |         |         |       |        |
| collection and        |       |         |         |       |        |
| conveyance*           |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Sump/piping upgrades  | 1 LS  | 5,000   | 5,385   | 5,000 | 5,385  |
+-----------------------+-------+---------+---------+-------+--------+
| Sump installations    | 2     | 6,000   | 6,462   | 3,000 | 323    |
| (2)                   | each  |         |         | each  | 1/each |
+-----------------------+-------+---------+---------+-------+--------+
| Subtotal              |       | 11,000  | 11,847  |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| *Constructed wetlands |       |         |         |       |        |
| pilot test*           |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Field technician      | 48    | 28,800  | 31,020  | 60    | 646.   |
|                       | days  |         |         | 0/day | 25/day |
+-----------------------+-------+---------+---------+-------+--------+
| Project management    | 30    | 18,000  | 19,388  | 60    | 646.   |
|                       | days  |         |         | 0/day | 26/day |
+-----------------------+-------+---------+---------+-------+--------+
| Cell construction^7^  | 1 LS  | 8,000   | 8,617   | 8,000 | 8,617  |
+-----------------------+-------+---------+---------+-------+--------+
| Lin                   | 1,200 | 1,800   | 1,938   | 1.    | 1      |
| er/geonet/geotextiles | SF    |         |         | 50/SF | .62/SF |
+-----------------------+-------+---------+---------+-------+--------+
| Import/placement of   | 110   | 2,750   | 2,962   | 25.   | 26     |
| substrate             | CY    |         |         | 00/CY | .93/CY |
+-----------------------+-------+---------+---------+-------+--------+
| Piping installation   | 1 LS  | 5,000   | 5,385   | 5,000 | 5,385  |
+-----------------------+-------+---------+---------+-------+--------+
| Water supply storage  | 1 LS  | 5,000   | 5,385   | 5,000 | 5,385  |
| tank                  |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Water sampling^8^     | 1 LS  | 5,000   | 5,385   | 5,000 | 5,385  |
+-----------------------+-------+---------+---------+-------+--------+
| Subtotal              |       | 74,350  | 80,080  |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Lime treatment system |       |         |         |       |        |
| decommissioning/pond  |       |         |         |       |        |
| closure               |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Lime treatment system | 1 LS  | 3,000   | 3,231   | 3,000 | 3,231  |
|                       |       |         |         |       |        |
| Decommissioning       |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Sludge                | 5,000 | 50,000  | 53,855  | 10.   | 10     |
| remova                | CY    |         |         | 00/CY | .77/CY |
| l/dewatering/disposal |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Verification sampling | 15    | 5,250   | 5,655   | 350/  | 377/   |
|                       | sa    |         |         |       | sample |
|                       | mples |         |         | s     |        |
|                       |       |         |         | ample |        |
+-----------------------+-------+---------+---------+-------+--------+
| Upper and lower pond  | 5,000 | 15,000  | 16,157  | 3.    | 3      |
| blackfill and         | CY    |         |         | 00/CY | .23/CY |
| compaction            |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Subtotal              |       | 73,250  | 78,898  |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Site                  |       |         |         |       |        |
| restoration/final     |       |         |         |       |        |
| reporting             |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Site cleanup/debris   | 1 LS  | 20,000  | 21,542  | 2     | 21,542 |
| removal               |       |         |         | 0,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Demobilization        | 1 LS  | 30,000  | 32,313  | 3     | 32,313 |
|                       |       |         |         | 0,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Final                 | 1 LS  | 35,000  | 37,699  | 3     | 37,699 |
| surv                  |       |         |         | 5,000 |        |
| ey/reporting/as-built |       |         |         |       |        |
| plan preparation      |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Revegetation          | 1 LS  | 25,000  | 26,928  | 2     | 26,928 |
|                       |       |         |         | 5,000 |        |
+-----------------------+-------+---------+---------+-------+--------+
| Subtotal              |       | 110,000 | 118,482 | #     |        |
|                       |       |         |         |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-24} |        |
+-----------------------+-------+---------+---------+-------+--------+
| SUBTOTAL              |       | 3,      | 6,      | #     |        |
|                       |       | 809,350 | 746,250 |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-25} |        |
+-----------------------+-------+---------+---------+-------+--------+
| CONTINGENCY           | 15%   | 571,402 | 1,      | #     |        |
|                       |       |         | 011,939 |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-26} |        |
+-----------------------+-------+---------+---------+-------+--------+
| TOTAL ESTIMATED       |       | 4,380   | 7,      | #     |        |
| CONSTRUCTION COST     |       | ,752.50 | 758,188 |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-27} |        |
+-----------------------+-------+---------+---------+-------+--------+

**Appendix---A continued**

+-----------------------+-------+---------+---------+-------+--------+
| Annual operation and  |       |         |         | #     |        |
| maintenance costs     |       |         |         |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-28} |        |
+-----------------------+-------+---------+---------+-------+--------+
| Site inspections      | 4     | 2,800   | 3,016   | 700   | 75     |
|                       | each  |         |         | /each | 4/each |
+-----------------------+-------+---------+---------+-------+--------+
| Site operations and   | 600   | 30,000  | 32,313  | 50    | 5      |
| maintenance           | hrs   |         |         | /hour | 4/hour |
+-----------------------+-------+---------+---------+-------+--------+
| Basin sediment        | 1,000 | 5,000   | 5,385   | 5/CY  | 5.4/CY |
| Removal/disposal^9^   | CY    |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| Monitoring well       | 12    | 7,200   | 7,755   | 600   | 64     |
| Sampling/analysis^10^ | each  |         |         | /each | 6/each |
+-----------------------+-------+---------+---------+-------+--------+
| Field supplies/repair | 1 LS  | 2,500   | 2,693   | 2,500 | 2,693  |
| parts                 |       |         |         |       |        |
+-----------------------+-------+---------+---------+-------+--------+
| *Subtotal*            |       | 47,500  | 51,162  | #     |        |
|                       |       |         |         |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-29} |        |
+-----------------------+-------+---------+---------+-------+--------+
| Contingency           | 15%   | 7,125   | 7,674   | #     |        |
|                       |       |         |         |   {#s |        |
|                       |       |         |         | ectio |        |
|                       |       |         |         | n-30} |        |
+-----------------------+-------+---------+---------+-------+--------+
| **TOTAL ESTIMATED     |       | 54,625  | 58,836  | #     |        |
| ANNUAL OPERATIONS AND |       |         |         |   {#s |        |
| MAINTENANCE COST**    |       |         |         | ectio |        |
|                       |       |         |         | n-31} |        |
+-----------------------+-------+---------+---------+-------+--------+

1\. Selection verification soil samples will be analyzed for pH,
priority pollutant metals, acid-generation potential, and
primary/secondary nutrients.

2\. The repository multilayered liner will include 60 mil HDPE smooth,
60 mil HDPE textured, 40-mil text.

3\. At least three monitoring wells will be installed upgradient and
downgradient of the repository.

4\. Earth quantities presented are preliminary. Final quantities will be
included in the engineered design.

5\. Construction costs will vary depending on final design constraints.

6\. Construction costs will vary pending negotiations with San Luis
Obispo County.

7\. Earthwork quantities assume a 3-foot-deep wetlands approximately 50
feet long and 20 feet wide. Final grades and elevations of the wetlands
will be determined following processed ore removal.

8\. Select influent and effluent samples will be analyzed for pH,
priority pollutant metals, and chronic/acute toxicity.

9\. Cost estimate done for sediment accumulation/removal using the
Universal Soil Loss Equation

10\. Assumes a minimum of three monitoring wells associated with the
repository will be sampled quarterly. Analytical costs may vary from
this estimate depending on RWQCB monitoring and reporting requirements

## B. Estimated Costs of Remediation Activities to Reduce Mercury in Clear Lake

**(after Cooke and Morris, 2002)**

+-------------------------+--------+------------+----------+----------+
| Remediation action      | No.    | Total cost | Price    | Unit     |
|                         | unit   | (TC) (\$)  | deflator | cost     |
|                         |        |            | 2003     | (\$)     |
|                         |        |            |          |          |
|                         |        |            | (TC)     |          |
|                         |        |            | (\$)     |          |
+-------------------------+--------+------------+----------+----------+
| [No                     | None   | 0 for Hg   | 0        | 0        |
| action]{.underline}:    |        | control    |          |          |
| Contaminated sediment   |        | activities |          |          |
| is expected to be       |        |            |          |          |
| buried passively under  |        |            |          |          |
| cleaner sediment        |        |            |          |          |
+-------------------------+--------+------------+----------+----------+
|   --------------------  |        |            |          |          |
|   **Mine site**         |        |            |          |          |
|                         |        |            |          |          |
|   --------------------  |        |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Waste rock controls     | 2      | 19--63     | 19.      | 9.5-     |
|                         | m      | million    | 38--64.3 | -31.5/CY |
|                         | illion |            | million  |          |
|                         | CY of  |            |          |          |
|                         | rock   |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Control surface water   | 50     | 18         | 183,6    | 0.0036   |
|                         | m      | 0,000--3.5 | 00--3.57 | --       |
| and runoff              | illion | million    | million  | .07/gal  |
|                         | gal/yr |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Control ground water    | 130    | 22--30     | 22.4     | 0.17 --  |
|                         | m      | million    | 4--30.60 | 0.23/gal |
|                         | illion |            | million  |          |
|                         | gal/yr |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Total mine site         | None   | 41.2 --    | 42.0     |          |
| remediation             |        | 69.5       | 2--70.89 |          |
|                         |        | million    | million  |          |
+-------------------------+--------+------------+----------+----------+
| Lakebed sediment        |        |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Dredge hot spots in     | 270 AC | 56--230    | 57.12    | 20,740   |
| eastern end of Oaks Arm |        | million    | --234.60 | --       |
|                         |        |            | million  |          |
|                         |        |            |          | 85       |
|                         |        |            |          | 1,851/AC |
+-------------------------+--------+------------+----------+----------+
| Dredge portions of Oaks | 780 AC | 140--930   | 142.     | 1        |
| Arm with Hg \> 25 ppm   |        | million    | 8--948.6 | 79,487-- |
|                         |        |            | million  |          |
|                         |        |            |          | 1,19     |
|                         |        |            |          | 2,308/AC |
+-------------------------+--------+------------+----------+----------+
| Deposit clean fill in   | 270AC  | 20 million | 20.4     | 7        |
| Oak Arm where Hg \> 50  |        |            | million  | 4,074/AC |
| ppm                     |        |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Reduce sediment         | 5,000  | N/A        |          |          |
| transport by subsurface | LF     |            |          |          |
| barriers to reduce      |        |            |          |          |
| wind- driven currents   |        |            |          |          |
| where Hg \> 25 ppm      |        |            |          |          |
+-------------------------+--------+------------+----------+----------+
| **Public outreach and   |        |            |          |          |
| education**             |        |            |          |          |
+-------------------------+--------+------------+----------+----------+
| Monitoring to assess    |        | \$35,000   | 35,700   | \$7,00   |
| progress toward         |        | --\$50,000 | --51,000 | 0--\$10, |
| water-quality           |        | every 5    | every 5  | 000/year |
| objectives              |        | years and  | years    |          |
|                         |        | additional |          |          |
|                         |        | \$40,000   |          |          |
|                         |        | every      |          |          |
|                         |        | 10^th^     |          |          |
|                         |        | year       |          |          |
+-------------------------+--------+------------+----------+----------+

## C. Carson River Mercury Mine Site

**(after Ecology and Environment, 2000)**

  --------------------------------- ------------------ -------------------
  **Remediation** action            **Total cost       **Price deflator
                                    (\$)**             2003 (\$)**

  Excavation                        350,000            371,420

  Transportation and disposal       810,000            859,572

  Backfill                          260,000            275,912

  Revegetation                      110,000            116,732

  Demolition                        60,000             63,672

  Well relocation                   50,000             53,060

  Hillside drainage system          60,000             63,672

  Mobilization/demobilization       450,000            477,546

  Compliance with Historical        310,000            328,972
  Preservation Act                                     

  Laboratory analysis               40,000             42,448

  *Subtotal*                        2,500,000          2,653,006
  --------------------------------- ------------------ -------------------

  -------------------------------- ------------------ --------------------
  **Project management**           Total cost (\$)    **Price deflator
                                                      2003 (\$)**

  Subcontractor field oversight,   350,000            371,420
  report                                              

  Subcontractor management         13,000             13,796

  Work plan development and        100,000            106,120
  management                                          

  Contractor fees                  30,000             31,836

  *Subtotal*                       493,000            523,172
  -------------------------------- ------------------ --------------------

  -------------------------------- ------------------ -------------------
  Direct compensation              Total cost (\$)    Price deflator 2003
                                                      (\$)

  Hotel/per diem paid for family   2,000              2,122
  relocation                                          

  Payment to property owners for   130,000            137,956
  demolition                                          

  Rental assistance to displaced   32,000             33,958
  tenants                                             

  *Subtotal*                       164,000            174,036

                                                      

  TOTAL PROJECT COST ESTIMATE      3,200,000          3,350,214
  -------------------------------- ------------------ -------------------

## D. Management Plan Costs for Control of Mercury Methylation in the San Francisco Bay Ecosystem

**(McFarland and others, 2002)**

  --------------------- ----------------- ----------------- -----------------
  Area type             Stations and      Receiver          Costs (\$)
                        samples                             

  Outside levee (tidal  20 stations; 5    Sediment (THg and 20,000
  salt marsh & mudflat) samples/station   MeHg)             

                                          Biota (THg)       4,000

  Inside levee (ponds,  20 stations; 5    Sediment (THg and 20,000
  drainage ditches,     samples/station   MeHg)             
  marshes)                                                  

                                          Biota (THg)       4,000

  Inside levee          5 stations; 5     Sediment (THg and 5,000
  (grassland)           samples/station   MeHg)             

                                          Biota (THg)       1,000

  Outside Hamilton      5 samples; 5      Sediment (THg and 5,000
  Airfield wetland      samples/station   MeHg)             
  (established salt                                         
  marsh, primary                                            
  channels                                                  

                                          Biota (THg)       1,000
  --------------------- ----------------- ----------------- -----------------

Cost estimates by task

  --------------------------- ----------------------- -----------------------
  **Task**                    **Description**         **Cost (\$)**

  Task #1: Relationships                              
  between MeHg and wetland                            
  type                                                

                              Labor                   81,712

                              Travel/boat time        67,917

                              Supplies                15,918

                              Chemical analysis       217,546

  Task #2: Risk of methyl                             
  mercury trophic transfer                            

                              Labor                   45,632

                              Travel/boat time        19,102

                              Supplies                7,428

                              Chemical analysis       90,202

                              Microbial analysis      23,346

  Task #3: Mitigation by                              
  wetland plants                                      

                              Labor                   212,240

                              Travel/boat time        8,490

                              Supplies                59,427

                              Chemical analysis       117,793

                              Microbial analysis      167,670

  Task #4: Microbial control                          
  of                                                  
  methylation/demethylation                           
  rate                                                

                              Labor                   182,526

                              Supplies                49,876

                              Microbial analysis      42,448

  General costs                                       

                              Final                   13,265
                              reporting/printing      

                              Travel for meetings in  29,714
                              San Francisco           
  --------------------------- ----------------------- -----------------------

##  E. Waste Pile Mine Remediation Costs

**(after MEND, 1995)**

**1. Range of estimated costs of engineered solutions for acid rock
drainage for waste rock piles (U.S. dollars/ton of waste) ^a^**

+-------------------+--------------------------------------------------+
| Remedial          | Cost (\$)                                        |
| technology        |                                                  |
+-------------------+--------------------------------------------------+
| Diversion ditches | 1.00/yd^3^ material moved --5.00/yd^3^ material  |
| and berms         | moved ^b^                                        |
+-------------------+--------------------------------------------------+
| Collect and treat | 0.02--0.14 ^b^                                   |
|                   |                                                  |
|                   | 0.24--0.57 ^c^                                   |
+-------------------+--------------------------------------------------+
| Collect and treat | 0.14--0.49 ^b^                                   |
| with soil cover   |                                                  |
|                   | 0.30--0.77 ^c^                                   |
+-------------------+--------------------------------------------------+
| Composite soil    | 0.81--1.02 ^b^                                   |
| cover             |                                                  |
|                   | 0.97--1.18 ^c^                                   |
+-------------------+--------------------------------------------------+
| Synthetic liner   | 9.36 yd ^2^--46.8 yd ^2\ c^                      |
| (200- year life)  |                                                  |
+-------------------+--------------------------------------------------+

a The values shown include only direct costs and not legal or permitting
expenses

b Capital unit costs

c Final unit costs

**2. Range of estimated costs of engineered solutions for acid rock
drainage for tailings (U.S. dollars/acre of tailings footprint) ^a^**

+-------------------------------+--------------------------------------+
| **Remedial technology**       | **Cost (\$)**                        |
+-------------------------------+--------------------------------------+
| Collect and treat             | 153,231--239,188 ^b^                 |
|                               |                                      |
|                               | **528,704--588,359** ^c^             |
+-------------------------------+--------------------------------------+
| Collect and treat with soil   | 224,582--450,335 ^b^                 |
| cover                         |                                      |
|                               | **494,783--652,693** ^c^             |
+-------------------------------+--------------------------------------+
| Composite soil cover          | 46,788--759,135 ^b^                  |
|                               |                                      |
|                               | **56,146--1,025,827** ^c^            |
+-------------------------------+--------------------------------------+
| Synthetic liner (200-yr life) | 52,632--734,572 ^b^                  |
|                               |                                      |
|                               | **59,655--998,924** ^c^              |
+-------------------------------+--------------------------------------+

a Upper estimates are capital costs, lower estimates are final costs.

b Capital unit costs

c Final unit costs

**3. Costs to treat acid rock drainage (dollars/gallon/minute flow)**

+-------------------+--------------------+----------------------------+
| Remedial          | Range of average   | Range of average annual    |
| technology        |                    | operating costs            |
|                   | capital cost       |                            |
+-------------------+--------------------+----------------------------+
| Lime              | \$3,               | \$802--4123/gal/min ^a^    |
| precipitation     | 322--7,331/gal/min |                            |
|                   | ^a^                |                            |
+-------------------+--------------------+----------------------------+
| Evaporation       | \$2,               | \$229--2520/gal/min        |
|                   | 290--6,872/gal/min |                            |
+-------------------+--------------------+----------------------------+
| Passive wetland   | \$3,3              | \$137--481/gal/min ^a^     |
|                   | 22--21,190/gal/min |                            |
|                   | ^a^                |                            |
+-------------------+--------------------+----------------------------+

a (Gusek, 1995)

## F. Unit Costs of Remedial Options for Hydraulic Mines

**(after CDM, 2002)**

+-------------+---------------------+---------------------------------+
| Remedial    | Equipment           | Unit costs (2003 deflator       |
| option      |                     | costs) (\$)                     |
+-------------+---------------------+---------------------------------+
| Mechanical  | Bulldozer           | 600 (612) -- 1,620 (1,652) /day |
| moving      |                     |                                 |
+-------------+---------------------+---------------------------------+
|             | Front-end loader    | 840 (857) -- 1,400 (1,428) /day |
+-------------+---------------------+---------------------------------+
|             | Track excavator     | 400 (408) -- 700 (714) /day     |
+-------------+---------------------+---------------------------------+
|             | Scrapers            | 960 (979) -- 1,700(1,734) /day  |
|             |                     | (23--31 CY capacity)            |
+-------------+---------------------+---------------------------------+
|             | Sheepsfoot          | 600 (612) -- 900 (918) /day     |
|             | compactor           | (300 Horsepower)                |
+-------------+---------------------+---------------------------------+
|             | Water truck         | 600 (612) -- 1200 (1224) /day   |
|             |                     | (3,200--5,000 gallons)          |
+-------------+---------------------+---------------------------------+
|             | Track-mounted       | N/A                             |
|             | drill; blasting     |                                 |
|             | supplies; offroad   |                                 |
|             | haul trucks         |                                 |
+-------------+---------------------+---------------------------------+
| Suction     | Vacuum truck        | 800 (816) -- 1,200 (1,224) /day |
|             |                     | (5,000 gallons)                 |
+-------------+---------------------+---------------------------------+
|             | Portable dredge     | N/A                             |
+-------------+---------------------+---------------------------------+
| Capping     | Bulldozer;          | Costs above                     |
|             | front-end loader;   |                                 |
|             | track excavator;    |                                 |
|             | offroad trucks;     |                                 |
|             | sheepsfoot roller   |                                 |
+-------------+---------------------+---------------------------------+
|             | Motor grader        | 560 (571) -- 900 (918) /day     |
|             |                     | (14-ft blade)                   |
+-------------+---------------------+---------------------------------+
|             | 1\. Low permeable   | 1\. 7--10/CY                    |
|             | soil;               |                                 |
|             |                     | 2\. 0.80--2.00/SF (material     |
|             | 2\. Geotextile clay | only)                           |
|             | liner;              |                                 |
|             |                     | 3\. 0.40--0.90/SF (material     |
|             | 3\. Geomembrane     | only)                           |
+-------------+---------------------+---------------------------------+
|             | Hydroseeder         | 1,500 (1,530) -- 2,000          |
|             |                     | (2,040)/AC                      |
+-------------+---------------------+---------------------------------+
|             | Native vegetation   | N/A                             |
|             | seed mixture        |                                 |
+-------------+---------------------+---------------------------------+
| Soli        | Jet grouting        | 150 (153) -- 225 (230)/CY (inc. |
| dification/ | (hydraulic mixing)  | labor)                          |
| st          |                     |                                 |
| abilization |                     |                                 |
+-------------+---------------------+---------------------------------+
|             | Soil mixing         | 40 (41) -- 100 (102)/CY (inc.   |
|             | (mechanical mixing  | labor)                          |
+-------------+---------------------+---------------------------------+
| Diversion   | Bulldozer; motor    | Costs above                     |
| channel     | grader; excavator;  |                                 |
+-------------+---------------------+---------------------------------+
|             | Backhoe w/ rock     | 300 (306) -- 400 (408) /day     |
|             | hammer              |                                 |
+-------------+---------------------+---------------------------------+
|             | Blasting supplies   | Casting: 3.00-6.00/CY; channel  |
|             |                     | excavation: 8.00-12.00/LF       |
+-------------+---------------------+---------------------------------+
| French      | Excavator;          | Costs above                     |
| drain       | geotextile;         |                                 |
+-------------+---------------------+---------------------------------+
|             | Clean aggregate     | 8.00-14.00/ton (1 ½ in)         |
+-------------+---------------------+---------------------------------+
|             | Perforated pipe     | 9.00-18.00/LF (installed cost)  |
+-------------+---------------------+---------------------------------+
| Recontour   | Bulldozer,          | Costs above                     |
| site; berms | front-end loader,   |                                 |
|             | track excavator;    |                                 |
|             | scrapes; offroad    |                                 |
|             | trucks; water truck |                                 |
+-------------+---------------------+---------------------------------+
| Breach mine | Bulldozer; track    | Costs above                     |
| site        | excavator; drill;   |                                 |
+-------------+---------------------+---------------------------------+
|             | Gas-powered         | 350 (357) -- 500(510) /day      |
|             | centrifugal and     |                                 |
|             | pump/hoses          |                                 |
+-------------+---------------------+---------------------------------+
|             | Microtunneling      | 500 (510) -- 750 (765) /ton     |
|             |                     | (inc. labor)                    |
+-------------+---------------------+---------------------------------+
| Slurry wall | Installation        | 4.00 -- 5.00/SF                 |
+-------------+---------------------+---------------------------------+
| Blast       | Bulldozer;          | Costs above                     |
| casting     | track-mounted;      |                                 |
|             | drill, and blasting |                                 |
|             | supplies            |                                 |
+-------------+---------------------+---------------------------------+
| Soil        | Soil nailing        | 40 (41) -- 100 (102) /CY        |
| nailing     |                     |                                 |
+-------------+---------------------+---------------------------------+
|             | Cut and fill (with  | 3.00-6.00/CY                    |
|             | compaction)         |                                 |
+-------------+---------------------+---------------------------------+

**Appendix F---continued**

+-----------------------+------------------------+---------------------+
| Remedial option       | Equipment              | Unit cost (2003     |
|                       |                        | price deflator      |
|                       |                        | costs) (\$)         |
+-----------------------+------------------------+---------------------+
| Reinforcement         | Retaining wall/timber  | 35 (36) -- 60       |
|                       | lagging                | (61)/SF             |
+-----------------------+------------------------+---------------------+
| Dewatering drainage   | French drain, fill     | Same as             |
| control               | wetland, diversion     | reinforcement costs |
|                       | surface channels;      |                     |
|                       | dewater wetland with   |                     |
|                       | evapotranspiration     |                     |
+-----------------------+------------------------+---------------------+
| Dewatering            | Vegetation; backhoe,   | Costs above         |
|                       | shovels                |                     |
+-----------------------+------------------------+---------------------+
| Mechanical            | 5 CY underground       | 750 (765) -- 900    |
| excavation/transport  | loader                 | (918) /day          |
+-----------------------+------------------------+---------------------+
|                       | Overshot mucker        | 480 (490) --600     |
|                       |                        | (612) /day          |
+-----------------------+------------------------+---------------------+
|                       | Installation of rail   | 18.00-25.00/LF      |
|                       | track for overshot     |                     |
|                       | mucker                 |                     |
+-----------------------+------------------------+---------------------+
| Hydrowash             | Water truck, pump,     | Costs above         |
|                       | hose                   |                     |
+-----------------------+------------------------+---------------------+
| Containment: jet      | Bulldozer, excavator,  | Costs above         |
| grouting, seal        | front end loader, low  |                     |
| openings, diversion   | permeable soil,        |                     |
| channels, material    | backhoe, blasting      |                     |
| screening;            | supplies, motor grader |                     |
|                       |                        |                     |
| hydraulics: tunnels,  |                        |                     |
| pipes                 |                        |                     |
+-----------------------+------------------------+---------------------+

### **Other unit costs**

  ------------------------- ---------------------------------------------
  **Equipment**             **Costs (2003 price deflator costs) (\$)**

  Dump truck                500 (510) -- 700 (714) /day (10 CY capacity)

  Articulated dump truck    900 (918) -- 1,100 (1,122) (30 CY capacity)

  Water wagon               200 (204) -- 350 (357) /day (high-pressure
                            pump)

  Standard processing       4.00-12.00/CY
  equipment                 

  Water treatment --        200 (204) -- 500 (510) /day (assumes rental
  filtration                or simple filtration equipment only)

  Water treatment           60 (61) -- 100 (102) /day (assumes use of
  clarification             retention pond and addition of flocculant)

  **Labor costs**           

  Superintendent            37 (38) -- 45 (46) /hour

  Operator                  22 (22) -- 38 (39) /hour

  Laborer                   18 (18) -- 25 (26) /hour
  ------------------------- ---------------------------------------------

Disclaimer: These prices do not include mobilization, labor, additional
transport costs (road construction), health and safety, disposal, design
and initial planning, site characterization, postmonitoring, final
reclamation, laboratory tests, and best management practices affiliated
costs.

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[^1]: PCA Water Code 13241 (2003). The other factors include the past,
    present, and probable future beneficial uses of water; environmental
    characteristics of the hydrographic unit under consideration; water
    quality conditions that could reasonably be achieved through the
    coordinated control of all factors affecting water quality in the
    area.

[^2]: Information on remediation costs was collected on numerous
    projects and sites for different years. For comparison purposes, a
    gross domestic price (GDP) deflator was used to adjust costs from
    one year to another using a GDP deflator inflation index
    (<http://www.jsc.nasa.gov/bu2/inflateGDP.html>). All of the costs in
    the text of this document report 2003 deflator costs. For original
    cost estimates, please review citations.

[^3]: The estimated unit costs shown are for additional treatment above
    what is already accomplished at Sacramento Regional Wastewater
    Treatment Plant. SRWTP currently removes approximately 95% of
    mercury from the influent. The removal efficiencies cited on this
    table are, for example, 97% of the 5% that currently remains in the
    effluent (Vicki Fry, SRCSD, written commun., 2003).

[^4]: http://calfed.water.ca.gov/ProgramTracking_2003/adobe_pdf/ERPProgramTracking_Jan2003.pdf
    for a list of active projects

[^5]: A fixed--effect variable is included in the regression to
    differentiate between abandoned mines as a possible remediation
    choice (an input that can be measured) and other remedial strategies
    that are not contributing as much mercury and are not direct loading
    sources.