First 5-Year Review
of the Non-Populated Area Operable Unit
Bunker Hill Mining and Metallurgical Complex
Shoshone County, Idaho
Approved by:
Michael F. Gearheard, Director
Environmental Cleanup Office
USEPA Region 10
Date:
September 2000
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Contents
Page
Executive Summary ES-1
Acronyms iv
1.0 Introduction 1-1
1.1 Statutory Requirements 1-1
1.2 Purpose of 5-Year Review 1-1
1.3 Relevant Guidance Documents 1-4
1.4 Rationale for Separate 5-Year Review 1-6
2.0 Site Chronology 2-1
3.0 Background 3-1
3.1 Site Location, Description, and Characteristics 3-1
3.2 Site History 3-1
3.3 Relationship of Site Activities with Coeur d'Alene Basin Investigation ... 3-5
3.4 Source and Nature of Contamination 3-5
3.5 State Superfund Contract and Two Phase Site Implementation Strategy . . 3-6
4.0 Review of Selected Remedies 4-1
4.1 Site-Wide 4-1
4.1.1 Bunker Hill Superfund Site 5-Year Review for Populated
Areas 4-1
4.1.2 Application of the Institutional Control Program 4-2
4.1.3 Health and Safety Review 4-4
4.1.4 Operation and Maintenance Plan 4-5
4.1.5 Activities Undertaken for the 5-Year Review 4-6
4.2 Site-Wide Monitoring 4-6
4.2.1 Surface Water and Groundwater and Air Monitoring 4-7
4.2.2 Hillsides Monitoring Program 4-13
4.2.3 Smelter Closure Observational Approach Monitoring 4-15
4.3 Review of Specific Site Work and Remedial Actions 4-17
4.3.1 Hillsides Remedial Action 4-17
4.3.2 Gulches Remedial Actions 4-27
4.3.3 Smelterville Flats Remedial Action 4-38
4.3.4 Central Impoundment Area Closure 4-47
4.3.5 Page Pond Remedial Action - PRP Implemented Remedial Action 4-54
4.3.6 Industrial Complex Remedial Action 4-63
4.3.7 Mine Operations and Boulevard Areas, Railroad Gulch
Drainage 4-73
4.3.8 Central Treatment Plant 4-77
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Page
4.3.9 Bunker Creek 4-80
4.3.10 Union Pacific Railroad Rights-of-Way - PRP Implement
Remedial Action 4-83
4.3.11 Milo Gulch and Reed Landing Remedial Action 4-89
5.0 5-Year Review Findings and Recommendations 5-1
5.1 Identification and Review of Newly Promulgated or Revised
Regulatory Standards 5-1
5.1.1 Air 5-1
5.1.2 Soil and Dust 5-2
5.1.3 Groundwater and Surface Water 5-2
5.2 Assessment of Remedial Actions 5-3
5.3 Recommendations and Required Actions 5-3
6.0 Statement of Protectiveness 6-1
7.0 Next 5-Year Review 7-1
8.0 References 8-1
Figures
1 Site Chronology 2-2
2 Site Map 3-3
3 Groundwater and Surface Water Monitoring Locations 4-11
4 CIA Location Map 4-49
5 Page Pond Site Map 4-55
6 Industrial Complex, Smelter Closure, and PTM Cell Locations 4-66
7 PTM Cell Plan View 4-69
8 PTM Cell Section 4-70
9 Milo Gulch Location Map 4-90
Tables
Table 4-1 TSP Ambient Air Quality Monitoring Results -Aggregate Results 4-10
Table 4-2 TSP Ambient Air Quality Exceedances - Individual Sites by Year 4-13
Table 4-3 Hillsides Remedial Actions 4-18
Table 4-4 Gulches Remedial Actions 4-30
Table 4-5 Smelterville Flats Remedial Actions 4-38
Table 4-6 Central Impoundment Area Remedial Actions 4-48
Table 4-7 Page Pond Remedial Actions 4-57
Table 4-8 Industrial Complex Remedial Actions 4-64
Table 4-9 Mine Operations and Boulevard Areas Remedial Actions 4-74
Table 4-10 Bunker Creek Remedial Actions 4-80
Table 4-11 UPRR Remedial Actions 4-84
Table 4-12 Samples with Highest Lead Concentrations 4-88
Table 4-13 Identified Barrier Deficiencies 4-88
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 4-14 Milo Gulch and Reed Landing Remedial Actions 4-93
Table 5-1 Summary of Initial 5-Year Assessment 5-4
Table 5-2 Summary of Recommendations and Required Actions 5-9
Appendix A: Identification of Newly Promulgated or Revised Regulatory Standards
Appendix B: Bunker Hill Hillsides Project Purpose, Goals, and Objectives
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Executive Summary
Introduction
This report summarizes the initial 5-year review of remedial actions implemented by the
Environmental Protection Agency (EPA) Region 10 and the State of Idaho at the Non-
Populated Areas operable unit of the Bunker Hill Superfund Site (Site) located in Shoshone
County, Northern Idaho. This 5-year review of remedial actions has been prepared to meet
the federal statutory requirements of the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA).
At the time of this initial 5-year review, full implementation of the site remedy had not yet
been completed. The purpose of this 5-year review is to document the remedial action work
conducted to date, and based on information at this time, to assess whether the remedy at
the Bunker Hill Superfund site, once completed, will be protective of human health and the
environment. Since the time from completion of the implemented remedial actions ranges
from months to a couple of years, adequate time has not passed to fully judge the
effectiveness of the specific remedial actions. Therefore, this initial 5-year review is not
expected to provide final definitive judgements on the effectiveness of the remedies
completed at the Site; but rather to be a starting point for ongoing monitoring and
evaluation of the overall site remedy.
EPA documents that define the selected remedy for the Non-Populated Areas of the Site
include:
• Record of Decision, Bunker Hill Mining and Metallurgical Complex, Shoshone County,
Idaho, September 1992.
• Amendment to the Record of Decision for the Bunker Hill Mining and Metallurgical
Complex (Non-Populated Areas) Superfund Site, September 3, 1996.
• Explanation of Significant Differences (ESDs) for Revised Remedial Actions at the
Bunker Hill Superfund Site, Shoshone County, Idaho: two separate ESDs, January
1996, April 1998.
Brief Site History and Chronology
Commercial mining for lead, zinc, silver, and other metals began at the Site in 1883. Mineral
processing and smelting began in the early 1900's and continued until 1981. Over the
following decades, the Silver Valley became one of the most important centers of metals
mining and processing in the United States. Milling of ore resuited in by-products (tailings)
that were routinely disposed in surface waters. In 1910, a plank and pile dam was
constructed along the South Fork of the Coeur dAlene River (SFCDR) at the Pinehurst
Narrows to retain the tailings. This retention dam deposited tailings throughout the
floodplain of the SFCDR in an area referred to as Smelterville Flats. The dam failed in 1933
resulting is some portion of the tailings spreading downstream. A second tailings
repository, the Central Impoundment Area (CIA) was initially constructed in 1928. This
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
tailings impoundment was expanded several times throughout its life as necessary to
receive more tailings and other waste materials (eventually to approximately 200 acres in
surface area).
Environmental contamination of surface water, groundwater, soil and sediment occurred
throughout the valley as a result of the mining, milling, and smelting processes. Vegetation
of the surrounding hillsides was gradually denuded from logging, deposition of air-borne
metals contamination, and acidification by sulfur compounds. Air-borne emissions affected
areas near the Smelter and Zinc Plant as well as the surrounding communities. Over time,
blood lead levels of children in the valley reached concentrations well above those
considered to be toxic.
In 1983, the federal government listed the site on its National Priorities List. Shortly
thereafter, EPA presented various orders to the companies held responsible for the
contamination (the Potentially Responsible Parties, PRPs) in an effort to begin remediation
of the environmental problems existing on the Site. PRP-supported investigation and
cleanup efforts ensued for about 10 years. Their efforts included conducting a Remedial
Investigation and Feasibility Study, initial cleanup of the smelter complex, terracing of the
denuded hillsides, and some re-vegetation work. EPA issued a Record of Decision (ROD) in
1992 describing the required remedy for the Non-Populated Areas of the Site (which had
been delineated as an approximate 21 square mile area).
In 1992 and 1994, two PRPs went bankrupt resulting in EPA and the State of Idaho
assuming responsibility for the majority of the Non-Populated Areas cleanup. Five
remaining PRPs signed Consent Decrees with EPA and committed to implementing those
remedial actions in the Non-Populated Areas of the Site that they agreed to perform. A
detailed chronology of site actions and remediations is included in Section 2 of this report.
Responsibilities for Remedy Implementation and
Long-Term Operations and Maintenance
In 1994, EPA and the State of Idaho entered into a cost-sharing agreement (as documented
in the State Superfund Contract) specific to those areas of the Site that EPA and the State
were performing remedial actions. These areas include:
Hillsides,
Gulches (Grouse, Government, Magnet, and Deadwood),
Smelterville Flats, north and south of Interstate 90,
Central Impoundment Area,
Industrial Complex (Lead Smelter, Zinc Plant, Phosphoric Acid Plant),
Boulevard Area and Railroad Gulch,
Mine Operations Area,
Central Treatment Plant,
Bunker Creek, and
Milo Creek and Reed Landing.
For these same areas, based on the requirements of CERCLA, the State of Idaho will be
responsible for 100-percent of long-term operations and maintenance (O&M).
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The five remaining PRPs (Union Pacific Railroad (UPRR), Stauffer Chemical, Hecla,
Sunshine Mining, and ASARCO) signed Consent Decrees with EPA and committed to
implementing and conducting long-term O&M for those Non-Populated Areas' remedial
actions that they agreed to perform. PRP-implemented remedial actions include:
Remediation of UPRR right-of-way through the Site - UPRR,
Closure of A-4 Gypsum Pond - Stauffer Chemical, and
Page Pond remediation - Hecla, Sunshine, and ASARCO.
For the portion of the site which EPA and the State are performing the cleanup actions, a
two-phased implementation strategy was agreed upon as documented in the State
Superfund Contract. Phase I work (reviewed in this initial 5-year review document)
includes source removals aimed at removing and consolidating extensive contamination
from various site areas, demolition of structures, development and implementation of an
Institutional Controls Program (ICP), future land use development, and public health
response actions. Phase I work also includes support studies for long-term water quality
improvement. Phase I was expected to last approximately 8 years (1995 through 2002).
Phase II will be implemented following completion of source control and removal activities
and evaluation of the effectiveness of these activities in meeting water quality improvement
objectives. This phase will consider any shortcomings encountered in implementing Phase I
and will specifically address long-term water quality, ecological, and environmental
management issues.
ROD Requirements
The selected remedy documented in the 1992 Non-Populated Areas ROD addresses both
human health and ecological aspects of the Non-Populated Areas of the Bunker Hill site
through the following general objectives:
• Minimize direct human contact with contaminants.
Reduce erosion of the hillsides.
Minimize windblown dust from contaminated areas.
Reduce suspended sediment and contaminant loading in surface water runoff to the
SFCDR.
Minimize migration of contaminants to groundwater.
Consolidate contaminated material removed during remedial actions in on-site
repositories and close these areas with engineered covers to reduce infiltration.
In addition to these general objectives, the remedy selected in the ROD is required to
comply with federal and state standards that are applicable or relevant and appropriate
requirements (ARARs). As part of this initial 5-year review, the ARARs identified in the
1992 Non-Populated Areas ROD were reviewed and any changes or newly promulgated
standards were identified and summarized (Appendix A). Section 5.1 of this report
summarizes revisions to existing ARARs or to be considered (TBC) documents initially
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summarizes revisions to existing ARARs or to be considered (TBC) documents initially
identified in the ROD, and newly identified regulations of TBCs.
Remedy Description
The selected remedy was designed to achieve the ROD objectives through a series of source
removals, surface capping, reconstruction of surface water creeks, demolition of abandoned
milling and processing facilities, engineered closures for waste consolidated on-site, and re-
vegetation efforts.
A brief description of each remedial action that is part of the overall site remedy is
summarized in Table ES-1. More detailed descriptions of the various remedial actions and
the specific ROD requirements that apply to each action are presented in Section 4 of this
report.
Table ES-1
Summary of Remedial Action Descriptions
Remedial Action
General Description of Remedial Action
Implemented by EPA and State of Idaho
Hillsides
Reduce erosion, increase infiltration, and minimize direct
contact by contouring, terracing, and re-vegetating
hillsides areas that are essentially denuded. Provide
surface armor or soil cover on mine waste rock dumps and
remove solid waste landfills to on-site consolidation areas.
Gulches (Grouse,
Government, Upper Magnet,
and Deadwood)
Reduce erosion, minimize direct contact, and minimize
migration of contaminants to surface and groundwater by
constructing erosion control structures and sediment
basins, removing contaminated soils above cleanup levels,
relocating the A-1 Gypsum Pond from Magnet Gulch to the
CIA, reconstructing Government and Magnet Creeks, and
installing surface barriers consistent with future land use.
Smelterville Flats (north and
south of Interstate 90)
Minimize direct contact, surface water erosion, and
migration of contaminants to surface and groundwater by
conducting extensive tailings removals throughout the
floodplain, depositing removed tailings on the CIA,
reconstructing portions of the SFCDR, providing soil
barriers and re-vegetation as necessary. Construct storm
drain/swale conveyance system for surface water
generated south of I-90 highway.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Table ES-1
Summary of Remedial Action Descriptions
Remedial Action
General Description of Remedial Action
Implemented by EPA and State of Idaho
Central Impoundment Area
Minimize dust dispersion, direct contact, and infiltration
through underlying contaminated materials by closing the
impoundment with an engineered cover of permeability
1 x 10"7 cm/sec or less. Minimize seepage to the SFCDR
by intercepting the CIA seeps located on the north side
of the CIA.
Industrial Complex (Lead
Smelter, Zinc Plant,
Phosphoric Acid Plant)
Minimize dust dispersion, direct contact, and potential for
migration to surface and groundwater; remove safety
hazards of abandoned facilities by recycling or
consolidating principal threat materials in a fully lined and
covered monocell, removing PCB transformers and PCB-
contaminated soils, removing asbestos material,
demolishing structures and consolidating debris in
Smelter Closure area, consolidating contaminated soil
and slag from site removals in Smelter Closure area,
demolishing 4 stacks in Smelter and Zinc Plant, and
constructing an engineered cover over the closure area
with a permeability of 1 x10"7 cm/sec or less.
Mine Operations and
Boulevard Area, Railroad
Gulch
Minimize direct contact, infiltration through contaminated
material, and erosion by demolishing structures,
removing contaminated soils to cleanup levels and
disposing in the Smelter Closure area, removing principal
threat materials and recycling or disposing in the Smelter
Closure, capping and re-vegetating disturbed areas, and
reconstructing Railroad Gulch Creek to increase surface
water flow capacity.
Central Treatment Plant
Treat acid mine drainage and contaminated site surface
waters to current NPDES discharge standards and
dispose of resulting sludge on top of the CIA. These
actions are considered interim measures. EPA and the
State are presently evaluating acid mine drainage issues
and long-term treatment issues for the Site. A separate
ROD documenting the evaluations and remedy selection
process is anticipated to be issued in 2001.
Bunker Creek
Minimize infiltration through contaminated soil,
contaminated sediment releases to surface water, and
direct contact by channelizing and reconstructing Bunker
Creek, removing contaminated surface soil to cleanup
levels, and capping and re-vegetating disturbed areas.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Table ES-1
Summary of Remedial Action Descriptions
Remedial Action
General Description of Remedial Action
Implemented by EPA and Sate of Idaho
Milo Creek and Reed Landing
Minimize sediment transport into Milo Creek from
adjacent tailings and waste rock dumps and surface
water infiltration into the underlying Bunker Hill mine
workings by lining the creek (pipe the flow) and removing
contaminated sources adjacent to the Creek as
practicable.
Implemented by PRPs
Page Pond
Minimize fugitive dust, direct contact and contaminant
releases to surface and groundwater by removing tailings
from the West Page Swamp, regrading, capping, and re-
vegetating the Page Pond impoundment and dikes,
diverting/modifying surface water channels into the
swamp areas, providing hydraulic controls to enhance
wetlands, and inundating remaining tailings.
Union Pacific Railroad Rights-
of-Way
Minimize fugitive dust and direct contact by "hot spot"
removals, soil/rock barriers, and re-vegetation.
A-4 Gypsum Pond Closure
Minimize dust dispersion and seepage from the
impoundment by placing a soil barrier, regrading, and re-
vegetating the surface of the Pond and providing a stable
channel for Magnet Creek flow across or through the A-4
Pond to Bunker Creek.
Monitoring Programs
The ROD requires periodic monitoring of soil, water and air at the Bunker Hill Superfund
site to provide information about the changing nature and extent of contamination of
various media. ROD-stated objectives of monitoring are:
To evaluate compliance with ARARs in surface water and groundwater,
To assess the status of environmental receptors (i.e., biological monitoring),
To evaluate the performance of specific remedial actions and their respective O&M
programs,
To evaluate success in meeting public health protection goals (i.e., continuation of blood
lead screening program),
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
To evaluate the adequacy of control measures instituted during the implementation of
remedial actions, and
To evaluate the success of remedial actions in protecting human health and the
environment and determine the adequacy of remedial actions selected in the ROD.
Monitoring is also used in conjunction with design to meet the objectives of the ROD.
Surface water, groundwater, and air monitoring at the Bunker Hill Superfund Site is being
performed in three different programs:
The Site-Wide Surface Water, Groundwater and Air Monitoring Program
• The Hillsides Monitoring Program
The Smelter Observational Approach Monitoring Program
These programs are described in Section 4 of this report.
The three monitoring programs will continue to be conducted, with annual reports
prepared to document trends observed. The site-wide monitoring program was initially
developed during the remedial investigation phase of the project (late 1980's) and was
initially planned to evaluate the general nature and extent of contamination throughout the
site. This site-wide monitoring program has been modified over the years for the purposes
of tracking site-wide trends as well as gathering needed remedial design data. Now that the
remedial designs and remedial actions are nearly complete, the site-wide monitoring
program (primarily surface and groundwater) will be re-evaluated and modified as
necessary to ensure that appropriate data are gathered to address remedial actions that have
been designed and implemented across the Site.
Biological monitoring of wildlife is currently being planned under an inter-agency
agreement between EPA and the U.S. Fish and Wildlife Service. This monitoring is expected
to begin in 2001. A description of the biological monitoring program and any results
obtained from this program will be addressed in a future 5-year review report.
Assessment of Remedial Actions
Table ES-2 provides a summary of this initial 5-year assessment for the Non-Populated
Areas of the Site. Included in the table are dates during which particular activities or
remedial actions were conducted, work that is remaining to complete the remedial action, a
general assessment of the performance or protectiveness of the remedy, and any deficiencies
noted during this 5-year review. This same table is repeated in the text of this 5-year
report in Section 5 as Table 5-1.
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table ES-2
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Activity
ICP Program within
Non-Populated Areas
1994- present
As part of individual
RAs, placement of ICP
barriers and fences at
various Site locations
As has been conducted to date,
EPA, IDEQ, and USACE will
continue to provide oversight of ICP-
related work in the Non-Populated
Area of the Site
None noted.
Health and Safety
During Remediations
1994 - present
Ongoing
Successful implementation of safety
programs as evidenced by no lost
time or injuries reported for prime
contractor
None noted.
Operations and
Maintenance of
Remedies
1994 - present
Day-to-day O&M
currently provided by
subcontractors to
USACE.
O&M being performed adequately.
None noted.
1999-2000
IDEQ in process of
preparing Site-Wide
O&M Plans
Not applicable (NA)
NA
Site-Wide Monitoring
1987-1993
1996-present
Ongoing monthly and
quarterly programs, data
reports, and trend
analysis prior to next
5-year review.
Insufficient data exists at this time to
establish trends between data and
effectiveness of remedies.
None noted.
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table ES-2
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Hillsides Monitoring
Program
1999 - present
Ongoing monitoring,
annual reports and
workshops to discuss
data modifications to RA
approach, if necessary
Adaptive management approach
working adequately.
None noted.
Smelter Closure
Observational
Approach
1997 - present
Ongoing monthly
sampling, yearly trend
analysis reports
As expected, insufficient amount of
post-remediation data to conclusively
determine trends at this time.
None noted.
Remedial Action
Hillsides RA
1990-1994
(PRPs)
1996 - present
(Fund-lead)
N/A
Re-vegetation programs
planned through 2001,
adaptive management
afterwards.
Upper Industrial Landfill
yet to be removed.
Terracing was effective. Planting
was marginally effective.
Adaptive management approach
working adequately. Raveling
hillslopes above Smelterville and
Wardner residential areas may need
additional monitoring and/or cleanout
to reduce potential for
recontamination.
None noted.
None noted.
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Table ES-2
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Gulches RA
Grouse: 1997
Govt: 1996-
1998
Magnet: 1995-
present
Deadwood:
1995- 1998
None noted.
Lower Gov't Creek re-
alignment. Riparian
planting.
Lower Magnet Creek
channel through A-4
gypsum pond to native
ground.
Riparian planting.
All Gulches:
Access control throughout gulches
and hillsides should be evaluated to
determine appropriate level of
concern (i.e., trail bikers have been
reported to use Grouse Gulch for
recreation).
Remedies are performing as
expected. Creek channels are
expected to become more stable
with time.
Determine need for access
restriction and if current access is
deficient implement greater
controls.
None identified.
Smelterville Flats RA
1996-1998
1999 - present
Plantings in Flats area.
Recapping of Truck
Stop area.
South of 1-90 storm drain
and ICP capping.
Special Area
Management Plan as
prepared by State of
Idaho
East of Theater Bridge
tailings removals and
capping
Remedy is performing adequately.
Channel of SFCDR is expected to
become more stable with time.
Truck portion of RV Park needs to
be re-capped to prevent direct
contact and dispersion of dust.
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Table ES-2
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Central Impoundment
RA
1995 - present
Final closure to be
completed in 2000.
Ongoing monitoring of
CIA seeps.
No assessment at this time; remedy
is only partially complete
None at this time.
Page Pond RA
1997 - present
Majority of RA yet to be
completed: Tailings
removal, placement of
clean fill, modifications
to South and North
Channels, construction,
of outlet and discharge
structures to SFCDR,
construction of internal
berms in West Swamp.
No assessment at this time; remedy
is only partially complete
Program for baseline and routine
groundwater and surface water
monitoring was reviewed by EPA
and the State and found to have
possible deficiencies. Revisions
to the monitoring program are
being considered.
Industrial Complex
RA
1995-1998
Remedy is performing adequately.
None noted.
Construction
season 2000
Borrow Area/ICP Landfill
construction.
Ongoing monthly
monitoring of
groundwater wells as
part of observational
approach.
Mine Operations Area
RA
1994
None noted.
Remedy is performing adequately.
None noted.
Boulevard RA
1997
None noted.
Remedy is performing adequately.
None noted.
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Table ES-2
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Railroad Gulch RA
1997
None noted.
Remedy is performing adequately.
None noted.
Central Treatment Plant
RA
1994 - present
Ongoing O&M
Remedy is performing adequately.
None noted.
Bunker Creek
1996-1997
ICP capping on west
end of Bunker Creek
project area.
Emergency overflow
channel to Gov't Creek.
Remedy is performing adequately.
Protectiveness from direct contact is
not yet achieved until all areas
receive ICP cap.
None noted.
UP Railroad RA
1995- 1999
A portion of the UPRR
right-of-way used as a
haul road remains to be
remediated by EPA.
Remedy is performing adequately;
verification sampling indicated that
none of the sampled areas exceeded
1,000-mg/kg lead. 1999 Sampling
Report did indicate that 7 areas
sampled did not have the required
thickness of ICP barrier.
Increasing barrier thickness in
some locations is warranted as
indicated by 1999 sampling.
Milo Creek and Reed
Landing RA
1995-2000
None noted.
Remedy appears to be performing
adequately, however, much of the
remedy has been constructed in last
2 years and will require more time to
determine effectiveness and
protectiveness.
None noted.
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Recommendations and Required Actions
As part of this 5-year review, recommendations and required actions were identified to
improve remedy performance or protectiveness in alignment with the Remedial Action
Objectives and performance standards of the Site. Section 5, Table 5-2 of this 5-year review
summarizes the specific recommendations and required actions that have been identified for
the various monitoring activities and remedial actions. Also identified in Table 5-2 are parties
responsible for implementation and oversight, proposed completion milestone dates, and the
potential to affect protectiveness of the remedy.
Recommendations and required actions resulting from this initial 5-year review include:
Evaluate the need for additional efforts to encourage vegetative growth at the Page Mine
Waste Rock Dump.
Evaluate the need for an Explanation of Significant Differences or ROD Amendment to
address groundwater control and collection systems and creek lining in Government
Gulch.
Evaluate the site-wide monitoring program to confirm that appropriate data is being
gathered to assess remedy performance across the Site.
Evaluate the need for an Explanation of Significant Differences or ROD Amendment to
address the adaptive management approach adopted for the hillsides remedial action.
Inspect catchment walls at the base of Smelterville and Wardner hillsides to determine if
additional action is necessary to prevent recontamination.
Assess the need for additional access controls to hillsides and gulches.
Develop and implement operations and maintenance procedures for all remedial actions,
including measures to address recontamination potential.
Conduct yearly surveys of gulch remedial actions to evaluate channel and surface barrier
stability, success of vegetation, and surface water and groundwater quality.
Develop and implement a biological monitoring program for the Site.
Clean out sediment from the bottom of the Lined Pond.
Evaluate the areas of the Union Pacific Railroad right-of-way that were identified as
having insufficient barrier thickness to determine the scope of work necessary to
reestablish the prescribed thickness.
Evaluate the need to cover mine waste and tailings disposed in tlhe Milo Creek Guy
Caves area with clean material.
Evaluate the need for an Explanation of Significant Differences or ROD Amendment to
address increased tailings removal on the Flats and the decision to defer construction of
the groundwater and surface water wetland treatment systems.
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Evaluate the need for an Explanation of Significant Differences or ROD Amendment to
address the deferment of construction of a seep collection system at the Central
Impoundment Area.
Conduct an evaluation of new groundwater and surface water quality criteria or standards
and the recently issued TMDL to determine their status as ARARs or TBCs.
Statement of Protectiveness
Overall, the remedy being implemented in the Non-Populated Area operable unit of the
Bunker Hill Superfund Site is expected to be protective of human health and the
environment upon completion, provided that the recommendations identified above are
implemented. Although the remedy hasn't been fully implemented, immediate threats to
human health and the environment have been addressed by source removal efforts, capping
activities, erosion control measures, ongoing treatment of mine water, and institutional
controls. The site requires ongoing reviews.
Next 5-Year Review
Statutory requirements of CERCLA require ongoing 5-year reviews for Superfund sites once
remediations have been initiated. The next review will be conducted within 5 years of the
completion date of this 5-year review report. The completion date is the date of the
signature shown on the cover of this report. This subsequent review will cover all remedial
work, monitoring, and O&M activities conducted at the Site. This subsequent 5-year report
is expected to summarize more detailed information on protectiveness of the remedy since
five additional years of monitoring data and annual remedy inspection reports will then be
available to judge remedy performance.
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Acronyms
Administrative Orders on Consent (AOC)
Applicable or Relevant and Appropriate Requirements (ARARs)
Best Demonstrated Available Technology (BDAT)
Bunker Limited Partnership (BLP)
Center for Disease Control's (CDC)
Central Impoundment Area (CIA)
Central Treatment Plant (CTP)
Code of Federal Regulations (CFR)
Coeur d'Alene Tribe (Tribe)
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
Environmental Protection Agency (EPA)
Explanation of Significant Difference (ESD)
Feasibility Study (FS)
Federal Emergency Management Administration (FEMA)
Federal Water Quality Criteria (FWQC)
Health and Safety (H&S)
Idaho Department of Environmental Quality (IDEQ)
Institutional Controls Program (ICP)
Mean sea level (MSL)
micrograms per cubic meter (|ig/m3)
micrograms per deciliter (|ig/dL)
micrograms per liter (|ig/L)
milligrams per kilogram (mg/kg)
Mine Operations Area (MOA)
Minimum Contaminant Level (MCL)
Morrison-Knudsen (MK)
National Ambient Air Quality Standards (NAAQS)
National Contingency Plan (NCP)
National Prionty List (NPL)
Operation and Maintenance (O&M)
Page Pond Wastewater Treatment Plant (PPWTP)
Panhandle Health District (PHD)
Potentially Responsible Parties (PRPs)
Principal threat material (PTM)
Quality Assurance and Quality Control (QA/QC)
Record of Decision (ROD)
Remedial Action Objectives (RAOs)
Remedial Design (RD)
Remedial Investigations (RI)
Remedial Investigation and Feasibility Study (RI/FS)
Removal Verification Team (RVT)
Resource Conservation and Recovery Act (RCRA)
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Rights-of-Way (ROWs)
Safe Drinking Water Act (SDWA)
Smelterville Flats (Flats)
South Fork of the Coeur d'Alene River (SFCDR)
Special Area Management Plan (SAMP)
State Superfund Contract (SSC)
Total Maximum Daily Load (TMDL)
Toxic Substance Control Act (TSCA)
Total suspended particulate (TSP)
Total suspended solids (TSS)
Union Pacific Railroad (UPRR)
Upstream Mining Group (UMG)
U.S. Army Corps of Engineers (USACE)
U.S. Bureau of Land Management (USBLM)
U.S. Fish and Wildlife Service (USFWS)
Washington State University (WSU)
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1.0 Introduction
The Environmental Protection Agency (EPA) Region 10 has conducted the first 5-year
review of the remedial actions implemented at the Bunker Hill Superfund site (Site) located
in Shoshone County, Northern Idaho. The Site is divided into two operable units, the
Populated Areas and the Non-Populated Areas. This 5-year review addresses the Non-
Populated Area review and was conducted from January through June 2000. The Populated
Area is addressed in a separate 5-year review document.
1.1 Statutory Requirements
The Record of Decision (ROD) for the Non-Populated Areas of the Bunker Hill Superfund
site was signed in 1992 (EPA, September 1992). The selected remedy addressed both human
health and ecological impacts to the Non-Populated Areas. Remedial designs and
implementation of the selected site remedy was begun in 1994.
This 5-year review of remedial actions in the Non-Populated Areas of the Bunker Hill site
was conducted to meet federal statutory requirements. Hazardous substances in the Non-
Populated Area of the Bunker Hill Superfund site are being addressed in accordance with
the requirements of the federal Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA) Section 121(c), as amended, and the National Contingency Plan
(NCP) Part 300.430(f)(4)(ii) of the Code of Federal Regulations (CFR).
The methods, findings, and conclusions of the review are documented in this initial 5-year
review report. In addition, this report summarizes deficiencies found during the review and
provides recommendations to address them.
This is the first 5-year review for the Non-Populated Area of the Bunker Hill Superfund site.
Remedial actions at the Site were initiated in the Fall of 1994. Since some of the remedial
actions performed or planned in the Non-Populated Area at the Bunker Hill site have
resulted or will result in hazardous substances remaining at the Site that will restrict future
uses, a 5-year review of the Bunker Hill site must be completed to meet statutory
requirements.
1.2 Purpose of 5-Year Review
1.2.1 General
The purpose of 5-year reviews on Superfund sites is to evaluate whether the selected
remedial actions are protective of human health and the environment. For remedial actions
that have not been completed, the 5-year review will determine if immediate threats have
been addressed and if remedies are expected to be protective when remedial actions are
complete. The main purpose of the 5-year review is not to reconsider decisions made during
selection of remedies, but to evaluate the implementation and performance of remedies.
However, in some situations, the 5-year review contains recommendations that remedies be
re-evaluated or that additional response actions be considered. Examples of situations that
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
might result in re-evaluation of remedies or consideration of additional response actions
include finding that a remedy will not adequately reduce levels of a contaminant of concern or
finding that a new contaminant, source, or pathway of exposure has been identified or has not
been sufficiently addressed. Where necessary, the 5-year review report will include
recommendations to improve the protectiveness of the remedy and address deficiencies
identified during the review.
1.2.2 Specific to Bunker Hill
As noted in Section 1.1, implementation of select remedial actions at the Non-Populated Areas
Bunker Hill site was begun in 1994. When remedial actions were initiated, it was projected that
full implementation and completion of all required remedial actions would take place over a
period of 10 or more years. Currently after 5 years, while many remedial actions have been
completed, several additional remedial actions are either in the design phase, or are being
implemented and are partially complete. In addition, many of the remedial actions have only
recently been completed. As such, their time from completion may range from months to a
couple of years, and adequate time may not have passed to judge the effectiveness of the
specific remedial action.
Based on the staged implementation and completion of the site remedial actions, this initial
5-year review is not expected to provide final definitive judgements on the effectiveness of the
remedies completed at the Site; but rather to be a starting point for ongoing monitoring and
evaluation of the overall site remedy. For example, in the future, as remedial activities progress
and the ability of these activities to achieve water quality improvement objectives for the Site
becomes clearer, the 5-year review will be expanded to include an assessment of the need for
any further remedial actions. Likewise, the extent of any site recontamination issues, which was
not considered as part of this 5-year review process, will be evaluated as part of future
processes. See Table 5-2, Recommendations and Required Actions. A chronology of the Site
that includes the staged implementation of remedial actions is shown in Section 2. A schedule
for future 5-year reviews is summarized in Section 7.
Heavy metals contamination in soil, sediment, surface water, and groundwater throughout the
site has impacted both human health and biological resources. Concerns in the populated
areas of the site are primarily related to human health, whereas environmental concerns exist
predominantly in the non-populated areas. Previous environmental studies conducted within
the Site have indicated exposure of biological resources to elevated metals concentrations and a
lack of vegetative cover resulting in loss of wildlife habitat.
Most of the remedial actions at the Site are expected to benefit both humans and biological
resources in the following ways: preventing or minimizing the potential for direct contact with
contaminants, minimizing releases of contaminants to surface water, limiting contaminant
loading to groundwater, and minimizing erosion and contaminant transport. Some actions, for
example, improving wetland vegetation and reestablishing riparian habitats, are aimed more
specifically at biological receptors.
As identified in the ROD, removal of all contaminants to levels below those believed to have
an impact on biological resources is believed to be infeasible. Habitat establishment, however,
is both feasible and desirable. As remedial actions progress, additional habitat is established,
and wildlife are recruited to the area, it is expected that aquatic and terrestrial
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
organisms will be exposed to residual levels of contaminants. As discussed in Section 4.2 of
this document, a biological monitoring program is being developed in order to evaluate the
exposure of biological resources to contaminants of concern. As with this and other site
monitoring programs discussed in Section 4.2, it is expected that future 5-year reviews will
also include an expanded discussion of monitoring results. These results will be considered
and evaluated when assessing the need for any further cleanup actions in the non-
populated area of the Site.
1.2.3 5-Year Review Process
This 5-year review consisted of a review of relevant documents and interviews with various
individuals familiar with specific remedial activities. The report was reviewed by
representatives of the EPA, the U.S. Army Corps of Engineers, the State of Idaho Division of
Environmental Quality (DEQ), the Panhandle Health District, contractors for EPA and DEQ,
and various representatives of the federal and state natural resource trustees including the
U.S. Department of Interior, U.S. Department of Agriculture, the Coeur dAlene Tribe, and
Idaho Fish and Game. The federal and state natural resource trustees have participated in
the remedial investigation, feasibility study, remedy selection, and remedial action
processes for the Bunker Hill Superfund site. General notification was made of the
upcoming review in fact sheets and at Bunker Hill Superfund Site Task Force meetings. The
Cities of Wardner, Smelterville, Pinehurst and Kellogg were advised of the upcoming
review, as well as the Shoshone County Commissioners. In addition, a draft annotated
outline of the 5-year review report was submitted for comment to the Bunker Hill
Superfund Task Force, federal and state natural resource trustees, and the Peoples Action
Coalition. A fact sheet announcing the draft findings of the 5-year review process and the
availability of the draft document for public review and comment was issued, and a public
meeting was held to discuss the draft findings of the 5-year review report. The public
comment period was held for 45 days.
During the public comment period, comments on the 5-year review report were submitted
by the U.S. Fish and Wildlife Service, Hecla Mining Company on behalf of the Upstream
Mining Group, a private citizen, MFG, Inc. on behalf of the Union Pacific Railroad, and the
Coeur dAlene Tribe. The comments have been taken into consideration by EPA and IDEQ
and incorporated into the final document to the extent possible. All comments received have
been incorporated into the administrative record. A brief summary of the comments is
included below, along with a brief response or where appropriate a reference to the section
of the document that has been modified to address the concern.
1.2.3.1 U.S. Fish and Wildlife Service (USFWS)
The USFWS expressed concerns that waterfowl in the Page Ponds area are exposed to lead
contaminated sediments, felt that the remedy may not be fully protective of biological
receptors at the Site, noted the potential for recontamination and continuing wildlife
exposures, and suggested that a biological monitoring program be undertaken to evaluate
the effects of remedial actions (The following sections of the document have been modified
to address these concerns: see Sections 1.2.2, 4.2, and 4.3.5.5 B).
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
1.2.3.2 Upstream Mining Group (UMG)
The UMG commented specifically on portions of the 5-year review document that discusses
the Page Pond remedial actions. Several inconsistencies were pointed out between the
discussion of Page Ponds in the Executive Summary versus that in the body of the text.
These issues have been addressed in this final document.
1.2.3.3 Private Citizen
A private citizen from Kellogg, Idaho wrote with concerns regarding the drinking water
supplied by the Central Shoshone County water district. Drinking water is not being
addressed as part of the Bunker Hill Superfund activities. This comment was referred to the
IDEQ regional field office in Coeur d'Alene to be considered during their assessment of
drinking water sources.
1.2.3.4 Union Pacific Railroad (UPRR)
The UPRR commented specifically on portions of the 5-year review document which discuss
the railroad right-of-way. An inconsistency was pointed out in the discussion of barrier
thickness provided in the Executive Summary versus that in the body of the text. This issue
has been addressed in this final document. Also, UPRR noted that they believe that the
right-of-way should not be considered as being fully incorporated into the institutional
controls program. The EPA and IDEQ disagree. The right-of-way will not be incorporated
into the institutional controls program until certification of completion has been issued.
1.2.3.5 Coeur d'Alene Tribe (Tribe)
The Tribe submitted two lengthy comment letters on the non-populated area 5-year review.
The Tribe's general comments focused on several key areas including: a concern that
biological resources may not be adequately protected by the remedy; a belief that site-wide
monitoring activities may not be sufficient to assess the effectiveness of the remedial actions;
that numerical performance standards have not been developed for all components of the
remedial actions by which to determine the success of the cleanup; that the potential for
recontamination and the need for any additional remedial actions was not addressed in the
document; that the document did not adequately describe the relationship of site activities
with the Coeur dAlene Basin investigation; and a lack of documentation of specific site
maintenance procedures and an assessment of their long-term effectiveness. The following
sections of the document have been modified to address these general concerns: see Sections
1.2.2, 3.3, 4.1.4, 4.1.2, 4.2, 4.3.5.5 B, 5.1, and Table 5-2. More detailed comments provided
by the Tribe on specific remedial actions, e.g., smelter closure, hillsides, gulches, central
impoundment area, the railroad right-of-way, and the industrial complex have also been
incorporated into the relevant sections of this document to the extent possible. In addition,
specific comments provided by the Tribe on possible enhancements to the site-wide
monitoring program will be further considered during the reevaluation of this program
which is noted in Table 5.2 Recommendations and Required Actions.
1.3 Relevant Guidance Documents
EPA has issued a draft guidance document titled Draft Comprehensive 5-Year Review
Guidance(EPA, October 1999) that was used for the preparation of this 5-year review. A
process for the review was developed in accordance with EPA guidance and site-specific
conditions at
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
the Bunker Hill site. The following steps were conducted to provide the summaries,
evaluations, and recommendations for this report:
1. Description of the work area or remedial action with a brief presentation of background
information,
2. Review of remedies selected in the ROD as amended or modified and identification of
performance standards and cleanup goals,
3. Description of work that has been performed and remains to be completed,
4. Discussion of Operation and Maintenance (O&M) considerations,
5. Assessment of remedy performance and conformance with ROD requirements, discussion
of newly identified information, and discussion of identified deficiencies and
recommended improvements, and
6. Description of documents reviewed and interviews completed for the review.
The conclusions of the review are summarized in this report with recommendations for
future actions to be taken at the Site, a statement of the level of protectiveness of ongoing
remedies, and a schedule for the next 5-year review.
Since the ROD was issued in 1992, various changes have occurred in the general approach
of implementing the selected remedy. A general shift towards increased source removals
across the Site (versus approaches that relied on a greater degree of long-term operations
and maintenance) was adopted by EPA and the State of Idaho, as documented in the
Comprehensive Cleanup Plan which is appended to the State Superfund Contract (State of
Idaho, 1995). Per CERCLA, remedy changes are required to be formally documented either
in an amendment to the ROD or in a document referred to as an Explanation of Significant
Differences (ESD). For the Bunker Hill Site, there has been one ROD amendment and two
ESDs prepared since the ROD was issued in 1992. The rationale for the remedy changes is
noted in this 5-year review document. Other potential changes to the remedy that may
require future ESDs or ROD amendments are identified and discussed later in this
document.
Current EPA documents that define the selected remedy for the Non-Populated Areas of the
Site include:
Record of Decision, Bunker Hill Mining and Metallurgical Complex, Shoshone
County, Idaho, September 1992.
• Amendment to the Record of Decision for the Bunker Hill Mining and Metallurgical
Complex (Non-Populated Areas) Superfund Site, September 3, 1996.
Explanation of Significant Differences for Revised Remedial Actions at the Bunker
Hill Superfund Site, Shoshone County, Idaho: two separate ESDs, January 1996, April
1998.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
1.4 Rationale for Separate 5-Year Reviews
When work first began in the early 1980's on investigation of the Bunker Hill area, elevated
levels of lead were found in the blood of children residing in the Populated Areas of the
Site. Because of the elevated blood lead levels, remediation of the Populated Areas of the
Site was given a higher priority over remediation of the Non-Populated Areas. A separate
remedial investigation and feasibility study (RI/FS), and a residential soil ROD (EPA,
August 1991) were completed to allow accelerated cleanup of the Populated Areas.
Separate 5-year reviews corresponding with the two separate RODs have been conducted
for the populated and Non-Populated Areas (operable units) of the Bunker Hill site. These
operable units have been managed as separate efforts throughout the study and cleanup
process. The decision by EPA to prepare separate 5-year reviews conforms with previous
decisions to conduct separate RI/FSs and prepare separate RODs for the populated and
Non-Populated Areas of the Bunker Hill site and reflects the different types of cleanup
activities carried out in these areas.
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1-6
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2.0 Site Chronology
Commercial mining for lead, zinc, silver, and other metals first began in the Coeur d'Alene
mining district in 1883. Over the following decades, the Silver Valley progressed to become
one of the most important centers of metals mining and processing in the U.S. One
ramification of this distinction, however, was the environmental contamination that resulted
from these activities. At one point, industrial output associated with the Bunker Hill Mine
alone peaked at over 2,500 tons of processed ore per day. In the meantime, groundwater
became heavily contaminated with metallic compounds with potentially detrimental human
health effects: lead, cadmium, mercury, arsenic, and others. Milling by-products, rich in
metals, were deposited on the floodplains of both major and minor drainages of the valley.
The vegetation of surrounding hillsides was gradually denuded from logging, fires,
deposition of air-borne metals, and acidification by sulfur compounds. Over time, blood
lead levels of children in the valley reached concentrations well above those considered to
be toxic leading to substantial health concerns.
Smelting activities in the complex ceased in 1981. Two years later, in 1983, the federal
government became formally involved with the cleanup of the Site when it listed the area
on its National Priority List (NPL). Shortly thereafter, EPA presented various orders to the
companies held responsible for the contamination (the Potentially Responsible Parties,
PRPs) in an effort to begin remediation of the environmental problems existing on the Site.
PRP-supported cleanup efforts ensued for about 10 years. Their efforts included funding of
numerous studies, initial cleanup of the smelter complex, terracing of the denuded hillsides,
and some re-vegetation work. However between 1992 and 1994, two PRPs went bankrupt.
As a result, EPA and the State of Idaho performed cleanup of those areas of the site that the
remaining PRPs would not agreed to perform. Consent Decrees for the cleanup work that
the remaining PRPs agreed to perform were signed and that work has also been
implemented.
A detailed listing of the chronology of the Site is shown in Figure 1.
09/26/00
2-1
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3.0 Background
3.1 Site Location, Description, and Characteristics
The Bunker Hill Mining and Metallurgical Complex Superfund Site (Figure 2) is located in
Shoshone County, in northern Idaho. The Site lies in the Silver Valley of the South Fork of
the Coeur d'Alene River (SFCDR). Figure 2 shows a site map identifying the key features of
the Bunker Hill site. The Silver Valley is a steep mountain valley that trends from east to
west. It has an average elevation of approximately 2,250 feet above mean sea level (MSL) at
the base of the valley and extends to approximately 4,500 feet MSL in the upper Milo Gulch
area. Interstate 90 bisects the Site east to west and parallels the SFCDR.
The Site is approximately 21 square miles in size, and has been impacted by over 100 years
of mining and 65 years of smelting activities. This has resulted in widespread contamination
of the Site with metals from a variety of sources. Contamination of soils, surface and ground
water, and air has occurred to varying degrees.
Further description of the physical and cultural setting of the Site can be found in the RODs
for the Non-Populated and Populated Areas of the Site (EPA, September 1992; EPA, August
1991).
3.2 Site History
The Bunker Hill site has a history of mining and metallurgy that spans approximately 100
years. Mining first began in the area during the mid-1880s. While various ore concentration
methods were employed at the Site prior to this time, actual smelting of ore did not begin
until 1917 when the Lead Smelter began operations. Zinc smelting began in 1928. Milling of
ore resulted in by-products (tailings) that were routinely disposed in surface waters. This
type of disposal in surface waters occurred in both the Bunker Hill site and upstream
milling sites as well. In 1910, a plank and pile dam was constructed along the SFCDR at the
Pinehurst Narrows (Figure 2) to retain the tailings. This dam resulted in tailings being
deposited in the current floodplain of the SFCDR or Smelterville Flats area. The dam failed
in 1933 resulting in some portion of the tailings being spread downstream of Pinehurst
Narrows. Other tailings impoundments at the Bunker Hill site included Page Pond, built in
1926, and the Central Impoundment Area (CIA), constructed in 1928 (Figure 2).
From the time of initiation of smelting through the 1960s, the Bunker Hill site was
dominated by industrial activity. Mining and the production of lead, zinc, silver, sulfuric
and phosphoric acids, and fertilizer were the primary activities occurring in the area.
Ultimately, milling capacity at the Site reached 2,500 tons per day. The 1970s began an era of
increased environmental concern about the Site. A 1973 fire in the baghouse of the Lead
Smelter stack led to increased emissions of lead particulates into the environment. This, in
turn, led to studies showing significantly increased blood lead levels in children living in the
immediate area. Subsequent actions taken during the latter 1970s resulted in at least partial
reduction in blood lead levels. Also, in 1977, tall stacks were constructed on the Site to help
disperse sulfur dioxide from the Site.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
The decade of the 1980s was one of official recognition by the federal government of the
Bunker Hill Mining and Metallurgy Complex as an environmentally contaminated area.
Initial studies focused on gathering data to understand the nature and extent of
contamination along with some initial remedial work. The Site was placed on the National
Priority List (NPL) in 1983. This year marked both the beginning of EPA presence in the
Silver Valley and the initiation of CERCLA activities at the Site. Various studies examined
both Populated and Non-Populated Areas of the Site and served to understand the range of
contamination as well as the assignment of liability associated with it.
The 1990s ushered in a number of environmental decision documents and the beginning of
EPA-directed cleanup work. Two RODS, one for the Populated Areas of the Site (Residential
Soil ROD) and one for the Non-Populated Areas, were released in 1991 and 1992,
respectively. In addition, three Administrative Orders on Consent (AOC) were issued by
EPA from 1990 to 1992 to the Site's PRPs directing work on the hillsides, the Mine
Operations Area (MOA), and elsewhere.
With the 1992 bankruptcy of one of the Site's PRPs (the Bunker Limited Partnership) and the
subsequent bankruptcy of the Site's major PRP (Gulf Resources) in 1994, EPA took control of
the Site in 1995 and entered into a contractual agreement with the State of Idaho (Idaho
Division of Environmental Quality (IDEQ) to jointly implement the majority of the ROD-
specified remedial actions for the Non-Populated Areas of the Site (IDEQ May 1995). Five
remaining PRPs (Union Pacific Railroad (UPRR), Stauffer Chemical, Hecla, Sunshine
Mining, and ASARCO) signed Consent Decrees with EPA and committed to implementing
those Non-Populated Areas' remedial actions that they agreed to perform. PRP-
implemented remedial actions include:
Remediation of UPRR right-of-way through the Site -UPRR,
Closure of A-4 Gypsum Pond -Stauffer Chemical, and
Page Pond remediation -Hecla, Sunshine Mining, and ASARCO.
EPA and the State of Idaho took on the responsibility of implementing the remaining
remedial actions at the following site areas:
Hillsides,
Gulches (Grouse, Government, Magnet, and Deadwood),
Smelterville Flats, north and south of Interstate 90,
Central Impoundment Area,
Industrial Complex (Lead Smelter, Zinc Plant, Phosphoric Acid Plant),
Boulevard Area and Railroad Gulch,
Mine Operations Area,
Central Treatment Plant,
Bunker Creek, and
Milo Creek and Reed Landing.
Design and implementation of both PRP- and government-implemented remedial actions
began in 1994. This 5-year review summarizes both PRP and government-lead activities.
A more detailed history of the Bunker Hill site is found in the Non-Populated Areas ROD.
09/26/00
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SOUTH FORK COEUR D'ALf-NE RIVER
SOUTH FORK COEUR D'ALENE RIVER
THEATER BRIDGE
_ /- TRUCK STOP
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IMPOUNDMENT
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, Closure'area*.
A*4 GYPSUM
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k /—WYOMING J
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'AGE MILL SITE
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/ ACID PLANT J -
,,a-1-Gypsum
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LANDFILLS. 3
GROUSE -
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.-NEVAl
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ID 50 2000 MOO
S'Xt •» "EET
Figure 2
Site Map
HUNKER HILL NON-POPULAT^C Atf£AS
INITIAL S-TTH REVIEW
-------
BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
3.3 Relationship of Site Activities with Coeur d'Alene Basin
Investigation
The Coeur d'Alene River Basin (Basin) encompasses 1500 square miles of land in northern
Idaho. The Basin, including Lake Coeur d'Alene, is the home of the Coeur d'Alene Indian
Tribe, and provides a variety of recreational uses. For over 100 years, the Basin has been the
center of very intensive metals mining and smelting activities. In the center of the Coeur
d'Alene River Basin sits the Bunker Hill Mining and Metallurgical Complex.
After the Bunker Hill site was placed on the NPL in 1983, EPA and the State focused their
studies and cleanup on an approximate 3-mile by 7-mile area centered on the Bunker Hill
Mining and Metallurgical Complex, the area of the most severe human health risk
historically. This 21-square mile area included the surrounding communities of Kellogg,
Wardner, Smelterville, and Pinehurst. The 1992 Bunker Hill Non-Populated Areas ROD
specifically identifies remedial actions that are to be conducted within this designated
21-square mile area. Actions selected in the ROD do not address sources of contamination
upgradient of the Bunker Hill Superfund Site, and while actions are expected to have
benefits to downgradient SFCDR water quality conditions over time, active remediation of
the SFCDR is beyond the scope of actions specified in the ROD.
In 1992, EPA, the State of Idaho and the Tribe entered into a Memorandum of Agreement to
establish the Coeur d'Alene Basin Restoration Project, an attempt to investigate a broad
range of environmental issues including agriculture, forestry, mining and urbanization. In
1996, EPA joined the federal natural resource trustees and the Tribe in a lawsuit against
various mining companies in the Basin seeking judgement of liability for cost recovery and
natural resource damages. The scope of the natural resource damage claim includes injuries
to natural resources within the 21 square mile area as well as the broader Basin. Over the
past several years EPA has been looking more closely at Basin-wide contamination issues.
In 1998, EPA initiated a RI/FS for the Coeur d'Alene Basin. The Bunker Hill Mining and
Metallurgical Complex is located within the boundaries of the Coeur d'Alene Basin
currently being investigated in the RI/FS.
The remediations conducted within the Bunker Hill 21-square mile site are being reviewed
and considered by the Coeur d'Alene Basin investigation team within the context of the
Basin's overall specific remedial objectives and will be coordinated with the Basin-specific
RI/FS documents.
For example, an evaluation of metals loading from all sources in the Basin, including the
Non-Populated Area of the Bunker Hill 21-square mile area, is included in the Coeur
d'Alene Basin RI/FS. It is possible that in the future additional cleanup actions in the Non-
Populated Area may need to be considered if determined necessary to meet overall cleanup
goals for the Basin.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
3.4 Source and Nature of Contamination
Contamination by heavy metals at the Site occurs in soils, surface and ground water, and
air. Sources of contamination included jig tailings, flotation tailings, inflow of contaminants
from upstream sources, air emissions from ore processing facilities, particulate dispersion
from ore stockpiles, and residuals from the Industrial Complex. Additional sources include
gypsum generated from phosphoric acid production and zinc fuming, and acidic, metals-
laden mine water emanating from the Bunker Hill Mine.
Jig and flotation tailings were generated as waste products during concentration of mined
ores. Jig tailings were generated by earlier mine concentrating techniques and were typically
dumped on the valley floor. During flood events, these tailings were transported by the
SFCDR, mixed with alluvium, and deposited on the flood plain. Over time, the valley floor
throughout the site became mantled with a mixture of jig tailings, flotation tailings, and
alluvium as floods occurred and as the SFCDR naturally meandered across the valley floor.
Flotation tailings, which were generated by an improvement to ore concentration methods
that came into predominant use in 1930, were typically discharged to the CIA. The flotation
tailings were identified during the RI/FS as an important source of air-borne contamination
as well as a source of contamination to ground and surface waters.
Air emissions occurred from ore processing facilities. Although both the Lead Smelter and
Zinc Plant had recycling processes designed to minimize air-borne particulates, significant
metals deposition still occurred together with deposition of sulfur dioxide emissions. These
affected areas near the Smelter and Zinc Plant as well as the surrounding hillsides.
Materials and residues from the Smelter Complex included ores, concentrates, sinter and
calcine, copper dross flue dust, lead residues, slag, gypsum, and other materials and wastes.
These materials were stored, transported, and occasionally spilled in various areas around
the Site. Gypsum was generated during production of phosphoric acid, and slag was
produced by fuming processes aimed at converting zinc to zinc oxide. For the most part,
these materials were either concentrated in ponds or deposited in the CIA. Acid mine
drainage was actively pumped to the east cell of the CIA until early 1991.
3.5 State Superfund Contract and Two Phase Site
Implementation Strategy
Per CERCLA requirements for Superfund remediations led by the Federal government, and
as noted above in Section 3.3, EPA and the State of Idaho entered into a cost-sharing
agreement specific to the Non-Populated Areas Bunker Hill site as documented in the State
Superfund Contract (SCC) (IDEQ and EPA, May 1995). In addition to defining the cost-
sharing agreements, the SSC had several documents appended to it that provided a
framework for decision-making and conducting the site cleanup. These appended
documents included:
• Support Agency Cooperative Agreement: Documents agreements between EPA and
the State concerning credits to the State for "in-kind" services and identifies those
activities the State will perform to satisfy their financial obligations per CERCLA.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
2. Performance standards for remedial actions (e.g. specifications for barriers),
3. An educational program for residents and contractors to familiarize themselves with
ICP requirements, and
4. A testing and monitoring program to evaluate the effectiveness of the ICP.
The Panhandle Health District (PHD) formally approved their involvement as the
management entity for the ICP in 1992 and proceeded to draft an Environmental Health Code,
known as the Contamination Management Regulations. These rules were adopted under
IDAPA 41.01 in February 1995.
The ICP includes management of a public disposal site for soil and other contaminated
material disposal, inspection of homeowner- and contractor-performed projects, and education
on the applicable elements of the ICP, health and safety awareness information, contractor
licensing and training, sampling assistance, and project tracking of construction activities for
particular properties to facilitate land transfers.
Performance standards for barriers were written into the Contaminant Management
Regulations. Barrier types vary depending upon the site use activities.
Educational program elements include:
Contractor licensing classes that are held twice each week;
Printing and distribution of educational flyers on the various aspects of the ICP;
Outreach, in the form of permit requirements, for projects exceeding 1 cubic ya" soil;
A full-time inspector who is available for permit issuance, contractor licensing,
health and safety awareness, community education, and sample assistance to identify
areas of concern.
These actions include capping, enforcing existing controls on access, and maintaining existing
fencing. These activities are intended to preclude migration of and human exposure to
contaminants (Panhandle Health District, 1996).
Portions of the Site will be transferred to the State of Idaho once remedial actions are
completed and performance standards have been achieved. ROD specified barriers (caps) are
required for most areas where surface soil concentrations exceed residential soil cleanup goals
for lead and which are likely to be developed. To facilitate the transfer of land and O&M
responsibility, the ROD caps have been installed to meet the ICP performance standards.
Once properties have been certified and transferred to the State, all of the elements of the ICP
will apply to any entity intending to develop or otherwise use those properties. Until such
time, however, ongoing monitoring and any necessary repair of completed remedial actions is
being performed by EPA through its contract with the US ACE.
A more thorough discussion of the ICP can be found in the Bunker Hill Populated Areas
Operable Unit First Five Year Review Report. In addition, both UMG (MFG, 1999) and the
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
State (TerraGraphics, 1999) conducted evaluations of the ICP, implemented by the
Panhandle Health District under local statute as described above.
4.1.3 Health and Safety Review
Construction work funded by EPA and the State of Idaho at the Bunker Hill Superfund site
was performed under the USACE Safety and Health Requirements Manual EM 385-1-1
(September 1996). In addition, each of the USACE's remediation contractors working at the
Site prepared their own project-specific health and safety (H&S) plan that met the
requirements of the USACE's site-wide plan. H&S plans prepared by remediation
contractors were then approved by the USACE. Within any given area of the Site, both the
USACE's H&S plan and the remediation contractor's project-specific H&S plan would be in
effect for all personnel in that area. Contractors were responsible for H&S for their own
project, including subcontractors, although the USACE monitored and enforced operations
for H&S compliance over the entire Site (Fink, 2000).
Accordingly, the prime contractor at the Site operated under their own USACE-approved
project-specific H&S plan that was consistent with requirements of the Occupational Safety
and Health Administration's Hazardous Waste Site Regulations (CFR 1910.129 and 29 CFR
1926.65). The H&S plan covered the following information (MK, 1999):
Hazard evaluation of the Site and work performed at the Site,
Training requirements for any and all personnel,
Actions required for medical surveillance of workers,
Required personal protective equipment,
Health and safety monitoring, including air, noise, heat stress, confined space,
perimeter, and mercury vapor monitoring;
Personnel sampling for lead exposure, asbestos, total and respirable dust, cadmium,
and arsenic;
Health and safety work precautions and procedures;
Site control measures such as establishment of work zones: support, contamination
reduction and exclusion zones, and related procedures;
Personnel and equipment decontamination and hygiene procedures;
Onsite first aid;
Emergency response plan; and
Record keeping requirements.
Subcontractors operated under a prime contractor's H&S plan or, in the case of specialty
work, prepared a site- and activity-specific H&S plan which was reviewed and approved by
both the prime contractor and the USACE.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Success of the H&S procedures and safety emphasis at the Site can be judged by the fact that
after five plus years, involving over 1,000,000 person-hours on the project with a work force
of over 200 personnel and 175 pieces of heavy equipment, no lost time accidents or injuries
occurred.
4.1.4 Operation and Maintenance Plans
In January 1999, the IDEQ and EPA began planning for the transfer of O&M responsibilities
from the federal government to the State of Idaho for those portions of the Bunker Hill site
that were cleaned up under the government-implemented program. The PRPs are
responsible for preparing O&M plans and conducting long-term O&M for the remaining
remedial actions at the Site that they are responsible for.
For the government-implemented remedial actions, the State of Idaho is taking the lead to
develop the O&M program for these portions of the Bunker Hill site. A report of the
progress that has been made to date on the State's O&M program was presented in the State
Lead Activity Update/Summary, Operation and Maintenance Project Bunker Hill Superfund
Site Memorandum, (TerraGraphics, December 23,1999). The development of the program has
included the participation of the local community including officials of Kellogg,
Smelterville, Pinehurst, Wardner, and Shoshone County. The goal of the State is to
efficiently transition remediated properties into productive use in accordance with land use
requirements while maintaining the integrity of the remedy.
Until the performance standards for specific remedial actions are met, and the State takes
over the operations and maintenance of those areas, ongoing monitoring and any necessary
repair of completed remedial actions is being performed by EPA through its contract with
the USACE. At the current time, while active cleanup work is ongoing, site personnel
routinely inspect completed remedial activities for any deficiencies and conduct repairs or
modifications as necessary. The State's O&M program described below, and the need for
planned and regular inspections of remediated areas, will be critical in the future as site
cleanup activities are completed, the number of site cleanup personnel is reduced, and land
is transferred over to State and private ownership for future development purposes.
The main features of the State's O&M program are described below.
4.1.4.1 Framework and Format Feasibility Study
As the State plans for taking on the O&M of the Site, it is investigating alternative means by
which O&M services can be delivered. Based on the current preliminary analysis of
alternatives, the most viable option is a phased approach, initially using an existing entity, i.e.,
IDEQ or the PHD, followed by creation and implementation of a new, long-term means such
as Charter Unit of Local Government or Legislative Action. Evaluations are ongoing to
further refine the manner in which the long-term O&M for the Site will be delivered.
4.1.4.2 Operation and Maintenance Manuals
Separate O&M manuals will be prepared for each remedial action. The O&M manuals are
being completed as a joint effort by IDEQ and EPA. The O&M manual for Smelterville Flats
was developed and is being used as a model for other plans. The Smelterville Flats O&M
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
manual was completed in May 2000 and began being implemented shortly thereafter
(TerraGraphics, 2000).
4.1.4.3 0&M Site-Wide Plan
All elements of the O&M program for the Bunker Hill site will eventually be presented in the
O&M Site-Wide Plan. The main elements of this plan include:
• Management Framework and Format: The selected means for delivering O&M
for the Site and how the O&M program will be administered will be presented.
• Property Management: Land use issues will be addressed, and the procedures for
property transfer.
• Site Inspection and O&M Requirements: These will be presented for each
remedial action.
4.1.5 Activities Undertaken for the 5-Year Review
Several sources of information and data were used to conduct this initial 5-year review for the
Bunker Hill site, including decision documents (i.e., the 1992 ROD, ROD amendment, and
ESDs); area-specific remedial design (RD) reports; construction plans and specifications; site
monitoring reports; remediation completion reports; and interviews with site personnel
involved in the specific remediations.
The references used for each remedial action review are summarized in Section 8 and listed
according to each particular remedial action. This list of references includes all documents
reviewed to evaluate each remedial action. Those references that are specifically cited within
the text of this report are shown to emphasize specific facts or data. Other references in
Section 8 that are not specifically cited within the text of the report are included as
background documentation.
4.2 Site-Wide Monitoring
The ROD requires periodic monitoring of soil, water and air at the Bunker Hill Superfund site
to provide information about the changing nature and extent of contamination of various
media. ROD-stated objectives of Non-Populated Area monitoring are:
To evaluate compliance with ARARs in surface water and groundwater,
To assess the status of environmental receptors (i.e., biological monitoring),
To evaluate the performance of specific remedial actions and their respective O&M
programs,
To evaluate the adequacy of control measures instituted during the implementation
of remedial actions, and
To evaluate the success of remedial actions in protecting human health and the
environment and determine the adequacy of remedial actions selected in the ROD.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Monitoring is also used in conjunction with design to meet the objectives of the ROD. Surface
water, groundwater, and air monitoring at the Bunker Hill Superfund Site is being performed
by EPA and the State in three different programs:
The Site-Wide Surface Water, Groundwater and Air Monitoring Program
• The Hillsides Monitoring Program
The Smelter Observational Approach Monitoring Program
These programs are described in general below. Biological monitoring of wildlife is
currently being planned under an inter-agency agreement between EPA and the USFWS.
This monitoring is expected to begin in 2001. A description of the biological monitoring
program and any results obtained from this program will be addressed in a future 5-year
review report. The purpose of the biological monitoring program is to evaluate the status of
biological resources and their habitat at the site, and thereby monitor the effectiveness of
remedial actions related to these resources. This program will address the monitoring
objective of assessing the status of environmental receptors as specified in the ROD. The
biological monitoring program is expected to evaluate the exposure of biological resources
to contaminants of concern and the extent to which habitat is reestablishing in remediated
areas. Monitoring activities will likely occur in the following areas at a minimum, Page
Ponds, Smelterville Flats, the South Fork Coeur dAlene River, the gulch areas, and the
hillsides, and include but not be limited to animal surveys, vegetation mapping, habitat
evaluation, and sampling.
4.2.1 Surface Water, Groundwater, and Air Monitoring
4.2.1.1 Background
From 1987 to 1993, surface water, groundwater, and air monitoring at the Bunker Hill
Superfund site was conducted by consultants to the PRPs. PRP sampling events were
carried out by Dames & Moore in 1987, 1988, and 1991 in support of the Site's RI/FS. PRP
monitoring programs conducted in 1992 and 1993 by McCulley, Frick and Gilman were part
of site-wide monitoring requirements of an AOC from EPA (U.S. EPA, 1990). The
bankruptcy of the primary PRP in 1994 resulted in EPA conducting the necessary site-wide
monitoring.
The air-monitoring program was restarted in 1995 by the Corps of Engineers to monitor
fugitive dust that could potentially be generated by the ongoing government cleanup efforts.
EPA and the State of Idaho provided oversight of the air-monitoring program. EPA
conducted the quarterly and monthly surface water and groundwater sampling programs for
one year beginning in October 1996. After that year, the State of Idaho took over the
groundwater and surface water site-wide monitoring responsibility and has continued from
October 1997 to the present.
4.2.1.2 Objectives
The site-wide surface water, groundwater, and air monitoring program is intended to record
and report on the changing nature and extent of contamination in the Non-Populated Areas as
remedial actions are implemented.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
The objectives for the site-wide groundwater and surface water monitoring are to:
Provide documentation on the condition of groundwater and surface water media
site-wide,
Support remedial design, and
Monitor the effectiveness of remedial actions.
When the program was re-started in 1996, existing monitoring wells and surface water sites
were used when at all possible. The groundwater wells were installed during several
different investigations over the past 10 years. During the last several years of remediation
work at the site, several wells have been destroyed or damaged such that monitoring in
these wells was no longer possible. The existing site-wide monitoring program will continue
to be evaluated, expanded and modified as necessary to obtain the data necessary to
evaluate performance of the remedies.
Figure 3 shows the locations of groundwater wells and surface water monitoring sites as of
January 1999. Groundwater and surface water samples are sampled on a quarterly basis.
A total of 61 wells are typically sampled during the quarterly monitoring programs. The
areas monitored and the number of wells in the vicinity of each area are:
CIA, Slag Pile, and CIA seeps-19 wells
Smelterville Flats (north of 1-90) - 8 wells
South of 1-90 - 7 wells
Lead Smelter - 8 wells
• Government Gulch - 6 wells
City of Kellogg - 2 wells
Industrial Landfill -1 well
Deadwood Gulch -1 well
Magnet Gulch -1 well
• Bunker Creek - 6 wells
• Lined Pond -1 well
• North of Pinehurst -1 well
The groundwater samples obtained from these wells are analyzed for dissolved arsenic,
antimony, cadmium, lead, mercury, zinc, and copper. Field parameters include
temperature, pH, conductivity, and groundwater level where possible.
The surface water-monitoring program is being developed to focus on metals concentrations
at Smelterville Flats and within the tributaries to the SFCDR upstream and downstream of
remediation areas, specifically:
SFCDR at east and west site borders -2 sites
Milo Gulch - 5 sites
Magnet Gulch - 2 sites
Deadwood Gulch - 2 sites
• Pine Creek-1 site
Bunker Creek - 6 sites
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Government Gulch - 6 sites
Page Pond
The 24 surface water sites are monitored for total and dissolved arsenic, mercury, lead, zinc,
copper and antimony and total suspended solids (TSS).
In 1995, air monitoring was reestablished for the purpose of monitoring air quality during
site remediation activities. The monitoring locations varied depending on where remedial
activities were occurring.
4.2.1.3 Results To-Date
A. Groundwater and Surface Water
In February 1998, EPA compiled a partial set of the results of the groundwater and
surface water sampling that had been performed to date (CH2M HILL, 1998). In
1999, IDEQ analyzed the results of the sampling that had been performed to date for
trends (TerraGraphics, 1999).
Presently, the State's trend analysis report exists in draft form only. This document
analyzed results from historic samples as well as data from the current surface and
groundwater-monitoring program through 1998. The trend analysis report will be
updated to include monitoring data collected in 1999. The memorandum concluded
that:
• There were not enough observations to determine trends over time. A
minimum of 15 to 25 observations collected, preferably at uniformly spaced
sampling events, are required for statistically valid conclusions of trending.
• A strong correlation between the presence and concentration of cadmium and
zinc was found across most areas of the Site. Discrepancies exist however,
which indicate extremely variable materials.
• Samples with arsenic readings exceeding the 50 |ig/L Safe Drinking Water Act
(SDWA) Maximum Contaminant Level (MCL) were found in only
6 wells on the CIA.
• Cadmium consistently exceeded 5 |ig/L (SDWA MCL) in wells throughout
the Site (29 of 34 wells) but only in 2 of 6 surface water sites.
• Lead exceeded 15 |ig/L (SDWA MCL) in 15 of the 34 wells, but only in 1 of
the 6 surface water samples.
• Zinc levels varied widely throughout the Site. Three of the four wells with
zinc levels greater than 100,000 |ig/L were in Government Gulch.
Smelterville Flats samples were generally lower than the rest of the Site with
none exceeding 50,000 |ig/L. The results of samples taken from Central
Impoundment Area (CIA) wells generally fell mid-range.
The fact that significant trends were not identified in the analysis was to a degree
anticipated since at the time of the last sampling event a great deal of work on the
remedial actions around the Site was being performed, and few of the remedial
actions and none of the remedies for an entire sub-area were completed.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Existing monitoring data is most useful to document the condition and variability of
pre-remedial and implementation stages of the remediations. As work progresses
and is complete at the Site, future 5-year review reports will continue to include a
discussion of surface water, groundwater, and air monitoring results to assess
remedy performance over time.
The primary conclusion concerning the status of the site-wide monitoring program is
the need to re-evaluate the program to determine if sufficient and appropriately
located data is being obtained to assess whether performance standards are being
achieved and whether the installed remedy is protective of human health and the
environment. EPA and the State of Idaho plan to conduct this re-evaluation of the
site-wide monitoring program beginning in 2001.
B. Air Monitoring Program
As noted above, the purpose of the air-monitoring program was to monitor fugitive
dust that may be generated during the various site cleanups. For the safety of the
general public, the applicable levels for comparison to measured data are the
National Ambient Air Quality Standards (NAAQS) for particulate matter less than
10 microns (PM10). Air monitors were installed around ongoing government
cleanup efforts implemented by the USACE and overseen by EPA and DEQ.
Table 4-1 is a summary of total suspended particulate (TSP) ambient air quality
results for the years 1995 through 1998 (CH2M Hill, 2000)' and a breakdown by
season.
Table 4-1
TSP Ambient Air Quality Monitoring Results - Aggregate Results
Total number of days monitored
814
Total number of 24-hour concentrations that
exceed NAAQS - 0.150 mg/m3 in the period from
June 1995 to January 1999
47
Number of 24-hour exceedances by season
Spring -10
Summer -18
Autumn -11
Winter - 8
Table 4-2 presents TSP exceedances for each site by year. It should be noted that data
exceedances do not necessarily indicate the presence of contaminants (i.e., the dust
could be "clean" dust).
' Suspended particulate matter measured at 10 microns or less (PM10) is a subset of total suspended
particulate (TSP).
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Legend
0 Groundwater Monitoring Wells
0 Surface Water Monitoring Locations
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-------
BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Table 4-2
TSP Ambient Air Quality Exceedances- Individual Sites by Year
Site / Year
1995
1996
1997
1998
Total Exceedances / Total
Measurements / Percentage
Bunker Avenue
0
0
0
6
6 out of 49 /12%
East Gate
0
3
2
2
7 out of 173/4%
East Gate - Collocated
0
2
4
1
7 out of 174/4%
Multi-plate
0
0
2
9
11 out of 54/22%
Pinehurst
0
0
3
1
4 out of 46 / 9%
Smelterville Gate
0
2
4
0
6 out of 135/4%
West Gate
0
0
3
2
5 out of 182/3%
Total Exceedances
0
7
18
21
46 out of 817/ 6%
The data in Table 42 indicates that a number of exceedances are associated with
heavy haul-route areas such as the "multi-plate" (overpass) structure built in
Smelterville to convey tailings parallel with Interstate 90 from the Smelterville Flats
to the CIA. This portion of the haul route has been removed and no longer needed2,
therefore, no further action is warranted with respect to these exceedances. All of the
site areas in Table 4-2 were used by construction equipment and these areas were
frequently watered to control dust. Some areas (such as the CIA and haul road) were
sprayed with dust suppressants including lignin and magnesium chloride on a
periodic basis. The air monitoring data indicates a need to continue and perhaps
increase dust suppression near active work areas, such as the ongoing CIA work that
began in 1999 and is scheduled to be completed in 2000. This monitoring will occur
as part of the CIA Closure contract and will be evaluated as part of the contractor's
performance. No new sources of fugitive dust have been identified since the RI/FS.
4.2.2 Hillsides Monitoring Program
4.2.2.1 Background/Objectives
In 1999, a Hillsides Monitoring Program was begun to measure plant growth, sediment
discharge, surface water quality, and other parameters in particular drainages impacted by the
re-vegetation and erosion control work on the hillsides (White, 2000a). This monitoring
program was designed during a series of workshops attended by EPA, IDEQ, USACE, U.S.
Bureau of Land Management (USBLM), Washington State University (WSU), TerraGraphics
and CH2M HILL that identified goals, objectives and performance standards for the Hillsides
work, summarized in greater detail in Appendix B (CH2M HILL, 1999). This program is
intended to:
2 This route was constructed with clean fill material, and trucks entering the haul route were
decontaminated before traveling the route.
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Measure achievement of project goals and objectives,
Validate the interim performance standards, and
Evaluate the effectiveness of the hillsides' design elements.
Evaluation of hillside design elements will be achieved using performance monitoring of the
particular remedial activities to ensure that they are performing as intended. Beyond this
evaluation, on-going monitoring will help to determine whether the remedial action goals are
being met and whether the remedies are protective.
A. Hillside Performance Monitoring Activities:
1. Aerial photography interpretation to estimate area percent cover (with ground-
truthing) in all treated management areas. Use color infrared photographs shot
during the annual June flight 2 years after the first construction season. (Infrared
aerial photographs provide better definition of vegetation than standard color
aerial photographs).
2. Aerial photography interpretation to estimate area percent cover in all major
gullies and on check-dam terraces3. Use color orthographic photographs shot
during annual June flights 2 years after the first construction season.
3. Use site inspection to look for evidence of regeneration from seed production,
new shoot growth, and sprouting from damaged or cut stems at the end of the
third growing season.
4. Perform site inspection to determine presence of noxious weeds listed in the
State of Idaho Noxious Weed Regulations at the end of the second full growing
season.
B. On-Going Hillside Performance Monitoring Activities:
1. Inspect each check dam after installation and at least once per year for proper
impedance/ retention of flow.
2. Continuously measure precipitation, air temperature and wind speed (White,
2000a) at a minimum of one weather station onsite. Continuously monitor
turbidity and flow at up to 10 sample sites situated in sub-watersheds that would
experience impact of check dams and plantings. Measure total suspended solids
(TSS) periodically at each station via grab sample.
3. Use results of metals analyses of surface water samples taken quarterly from
sites expected to be impacted by check-dams and plantings.
4. Convene project team at least annually to review the results of the monitoring
program and recommend acceptance or modification of the program for the
future.
4.2.2.2 Hillsides Monitoring Results To-Date
The monitoring program is not yet fully in place and the hillsides' remedy is not projected to
be fully installed until 2001. A pilot surface water-sampling program is currently being
3 Hay or straw bale "dams" staked into the ground on hillside terraces for the purpose of retarding or retaining
surface water runoff in order to minimize erosion and maximize water seepage into the hillside soils as much as
possible.
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established and data loggers installed. A weather station is in place. Check dams will be
inspected once they are all constructed. Initial data for all of these elements are expected by
late 2000. The entire monitoring program is expected to be operational at the time the
hillsides re-vegetation solution is completed in late 2001 (White, 2000b).
Data collected by the performance-monitoring program will be compiled by CH2M HILL.
These data will be presented in an annual monitoring results report.
Results of the performance-monitoring program will be reviewed by the project team every 2
years to guide the program in providing the information needed to ensure that the needs of the
hillsides' watersheds are being met.
Because the remedies are in the process of being implemented, monitoring data collected from
some stations may be considered as background data. Lack of background data from some of
the monitoring sites needs to be considered while evaluating data generated from the program.
Future 5-year review reports will include a discussion of hillsides monitoring results in order
to evaluate the performance of the hillsides remedy over time.
4.2.3 Smelter Closure Observational Approach Monitoring
4.2.3.1 Background
At the time the ROD was written, the Lead Smelter area was one of the most contaminated
areas of the Industrial Complex at the Bunker Hill Superfund site. The ROD required that
the Lead Smelter be demolished and contaminated materials consolidated and capped within
that area to limit direct contact with contaminants and control migration of contaminants to
surface and groundwater (EPA, 1992). With respect to seepage collection from the capped
Smelter Closure area (see Figure 2), the ROD also directs that other appropriate Resource
Conservation and Recovery Act (RCRA) requirements for closure of existing facilities will be
incorporated into the closure design (EPA, 1992).
During the predesign phase of the Smelter Closure area, a cost-benefit analysis was conducted
to evaluate the effectiveness of a groundwater seepage collection system downgradient from
the Smelter Closure. A groundwater interceptor trench was found to be infeasible due to the
high construction cost, combined with the presence of an extensive low
permeability-confining layer between the consolidated waste and the perched groundwater
table underlying the closure area. Based on this cost-benefit analysis, an observational method
was implemented to monitor groundwater quality at the down-gradient edge of the closure
over time (CH2M HILL, 1996a).
To address a minor amount of seepage that historically flowed along the ground surface of the
Smelter Closure area and into structure basements, a seepage toe-drain (approximately 4 feet
deep) was constructed along about 800 lineal feet of the 1,100-lineal-foot long northern edge
of the closure. The seepage collected from this toe-drain is hard-piped to the Sweeney Pump
Station located near McKinley Avenue north of the closure. This water is then conveyed to
the Lined Pond and the CTP for treatment.
The observational method for the Smelter Closure involves evaluating groundwater quality
down-gradient of the closure area by monitoring a network of groundwater wells in the
vicinity of the closure. When monitoring was started in 1996, 10 wells made up the network
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of wells monitored. During the construction of the Smelter Closure, 2 wells were damaged
and not replaced, therefore, the current network consists of 8 wells (2 up-gradient and
6 down-gradient). Six of the eight wells are being sampled monthly and two of the eight
wells are being sampled quarterly as part of the site-wide monitoring program for water
level, and dissolved and total lead, zinc, cadmium and arsenic concentrations (CH2M HILL,
1996b). Monitoring began in February 1997 and continues to the present.
The Smelter Closure cap was constructed over two seasons and was completed in 1998.
Based on flow computer modeling and permeability rates anticipated in the various Smelter
Closure cover elements (e.g., drainage layer, geomembrane, waste material, underlying
native soil, etc.), seepage that may result from within the waste is projected to decrease
rapidly in the first 3 years after final closure. Within 4 years of closure (December 2002), the
computer model projected that seepage from consolidated waste would approach the
steady-state value of less than 1 percent of the annual precipitation (CH2M HILL, 1996a).
Based on these analyses and the presence of the low permeability confining soil layer
underlying the closure, water quality, as measured at the down-gradient edge of the closure,
is not expected to be adversely impacted by the contaminated materials consoidated in the
closure. Should water quality measurements over time indicate that groundwater quality is
worsening as a result of the consolidated contaminated materials in the Smelter Closure, the
need for addition remedial actions will be evaluated.
4.2.3.2 Objectives of Smelter Closure Observational Approach Monitoring
The objectives of the Smelter Closure Observational Monitoring approach are to:
• Provide a cost-effective design approach based on the most probable site conditions.
• Establish a program to monitor reasonable deviations from probable conditions
including identifying parameters to be observed and evaluating actual conditions.
If necessary, select a course of action or remedial design modification based on the
observational findings. For example, if groundwater quality measurements (taken
up-gradient and down-gradient of the Smelter Closure area) indicate that water
quality is actually worsening over time, an evaluation will be conducted to determine
if the consolidated materials in the closure are the most likely source. If determined
as the source, additional remedial actions will be evaluated for the closure, such as
collection trenches and traditional treatment or in-situ treatment walls.
4.2.3.3 Results To-Date
Data is currently being collected and compiled. A draft memorandum describing the status
of the seepage monitoring with data evaluation for the interim period before the Smelter area
was capped was prepared in November 1998 (Turner, 2000). The next memorandum
presenting analysis of data collected through the second year after the cap was completed is
anticipated to be prepared by the third quarter of 2001. Future 5-year review reports will
include a discussion of monitoring results in order to evaluate the performance of the Smelter
Closure remedy over time.
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4.3 Review of Specific Site Work and Remedial Actions
4.3.1 Hillsides Remedial Action
4.3.1.1 Background
The hillsides within the Bunker Hill site have been impacted by 100 years of mining and
metals refining related activities. These activities include logging and clearing, mine waste
rock dumping, and emissions and fugitive dust from processing operations. Natural events
such as forest fires, wind and flooding have increased the impacts to the hillsides leading, to
severe erosion and reduced vegetation in many areas. The erosion of the contaminated soils
from the hillsides has resulted in contaminants being conveyed to the streams, gulches and
other areas.
In the ROD, the remedial action for the hillsides is based on the 1990 Pintlar AOC 1990 for
Re-vegetation and Stabilization. The major requirements of the ROD are shown in Table 4-3.
The remedial action is to focus on the approximately 3,200 acres of hillsides identified in the
AOC work plan. These areas were selected as the areas that were severely eroded, having less
than 50 percent vegetative cover. This is based on the Remedial Investigation (Dames and
Moore, 1990) that evaluated about 12,000 acres of the hillsides. Severely eroded areas
within the area that had more than 50 percent vegetative cover are also to be re-vegetated.
In the ROD, and in this initial 5-year review, the hillsides area includes the steep portions of
the site that slope upwards from the floor of the valley and/or gulches. The term "gulch
areas", as used in the ROD and this 5-year review, include the flat portions of the gulches
exclusive of the hillsides.
Clear project goals are fundamental to the development of design solutions for the hillsides.
Project goals identify the desired end point for land management. The AOC (EPA, 1990)
calls for areas having less than 50 percent cover to be re-vegetated, as well as for the
implementation of a number of slope stabilization and erosion control measures. The ROD
goes on to discuss an EPA-approved PRP workplan that seeks 85 percent ground cover
within 8 to 12 years. It also emphasizes the establishment of 100-foot-wide riparian
corridors. However, the ROD does not identify which stream systems are to receive this
treatment, neither does it state that all streams must receive treatment. The ROD also
expects re-vegetation efforts to occur in areas where there is a high potential for
contaminant transport and to develop new access where it is environmentally acceptable.
The primary purposes of the individual hillside remedial actions are (EPA 1992):
Contouring, terracing and re-vegetation are intended to control erosion and increase
infiltration.
• Erosion control structures and surface water treatment activities are intended to
reduce the suspended sediment/ contaminant loading in surface runoff to the
SFCDR.
Surface armoring, or covering the mine waste rock dumps, is intended to control
direct contact or erosion hazards.
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4.3.1.2 ROD Requirements
ROD requirements for the hillsides are summarized in Table 4-3.
Table 4-3
Hillside Remedial Actions
ROD Requirements
Remedial Action Objective/Goal
Document
1. Contouring, terracing and re-vegetation of
areas with <50% cover
Reduce erosion and increase infiltration
ROD 9.2.1
2. Spot re-vegetation of areas with >50%
cover within areas that are >50% cover
class and have high potential for
contaminant transport
Control erosion and increase infiltration
ROD 9.2.1
3. Surface armor or soil cover on selected
mine waste rock dumps
Control direct contact or erosion hazard
ROD 9.2.1
4. Enforce existing controls on access
Human contact
ROD 9.2.1
5. Maintain existing fencing
Human contact
ROD 9.2.1
6. Some or all of the solid waste landfill
material may be relocated to the Lead
Smelter Closure. Contour and re-vegetate
disturbed areas.
To reduce surface infiltration through
potential source materials; to reduce
potential groundwater loadings from these
sources
ROD 9.2.5/
ESD 12-95/
ESD 4-98
7. Surface water flows at the solid waste
landfill will be returned to their natural
conditions to the extent practicable.
Control erosion
ESD 12-95
The ROD also called for monitoring of the performance and maintenance of erosion control
structures until re-vegetation efforts are proven successful.
A. Implementation of Hillsides Work
The 1990 Hillsides AOC resulted in the PRPs beginning remedial work on the
hillsides prior to the ROD being finalized. The remedial work conducted by the PRPs
is described in Section 4.3.1.3, Description of Remedial Actions Conducted at the
Site. In general, the PRP-implemented work on the hillsides consisted of hillside
terracing, installation of check dams to minimize further erosion in gullied areas,
tree-planting programs, and erosion control measures at select mine waste dumps.
With the bankruptcy of the Site's primary PRP is 1994, EPA and the State took on the
responsibility of the additional hillsides remedial work necessary to achieve the
requirements of the 1992 ROD. The initial planning conducted by EPA and the State
was to review and refine the performance standards as necessary to result in a cost-
effective hillsides remedy. The process used to evaluate and document hillside
performance standards is described below.
B. Agency Guidance Statement Workshops
While the ROD provides general guidance regarding hillside remedial actions, it did
not define specific actions that could be used in actual projects. As a result, prior to
implementation of remedial actions on the hillsides, a series of three workshops
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(January and April 1998, April 1999) were convened to refine the purpose, goals, objectives,
and interim performance standards of hillsides remedial actions. The concept of the
workshops was to provide consensus-based guidance for developing specific re-vegetation
solutions within the spirit of the information provided by the ROD. A significant additional
benefit of the workshops is that they resulted in a platform for both a Monitoring Plan and a
short- and long-term Hillsides O&M Plan. At the time of this review, the Monitoring Plan
has been prepared. Participants in the workshops included EPA, US ACE, BLM, IDEQ and
their consultants including CH2M HILL, Dr. Ed DePuit (Washington State University), and
TerraGraphics.
Upon examination of the ROD, two general themes emerge: hillsides projects should
ultimately control erosion and sediment discharge and, as a secondary consideration, improve
the ecological function of the watershed. These themes were captured in two goals during the
workshop that ultimately are the drivers behind the hillsides design decisions (Appendix B).
The first goal is to improve overall watershed function by reducing runoff, soil erosion, and
pollutant transport. The project team is accomplishing this goal through re-vegetation,
installation of check dams, and other approaches. The second goal is to ensure that the design
approach provides a permanent solution to erosion and sedimentation control by using plant
species capable of natural reseeding or other forms of regeneration, and in addition, also
return supplemental societal or ecological value to the watershed. This goal is being
addressed by use of soil-building species and use of native species believed to be capable of
natural regeneration within the harsh hillsides environment.
In addition to providing more specific guidance than was used in the ROD, the workshops
formalized the process of adaptive management of the hillsides. This management technique
will result in periodic review of the hillside design solutions to ensure that the requirements
of the ROD and the needs of the overall project goals are met. The guidance statements
generated by these workshops are found in Appendix B and discussed in greater detail in the
Bunker Hill Hillsides Re-vegetation Conceptual Plan and Monitoring Plan (CH2M HILL,
1999).
These guidance statements form the basis for long-term monitoring of hillside performance.
As such, adaptive management will also allow for conversion of "interim" performance
standards to final performance standards. It will do so through monitoring of the standards in
the field for their success in meeting sediment discharge goals to the SFCDR.
While the output of the workshops has provided clear direction for work conducted on the
hillsides, the guidance statements may require more formal confirmation through an ESD. As
part of reviewing annual hillsides monitoring and trend reports, it is recommended that the
need for either an ESD or ROD Amendment be also evaluated to address the adaptive
management approach for establishing hillsides' performance standards.
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4.3.1.3 Description of Remedial Actions Conducted at the Site
A. Erosion Control Structures
Terraces. Mining companies built bench terraces, over a period of several years, as a
first step in a program of hillside stabilization. Pintlar Corporation installed
25.6 miles of terrace construction across 29 separate benches in 1992 (EPA, 1992).
Pintlar Corporation designed these bench terraces to have zero longitudinal slope
with an approximate 20 percent inslope (EPA, 1992). One bench was to be installed
for every 100 feet of elevation change, with each bench averaging 14 to 16 feet in
width (EPA, 1992). The highest terrace bench was constructed at an elevation of
about 3,700 feet. Prior to 1992, an additional 43 miles of terrace were constructed. In
total, approximately 69 miles of terraces have been constructed in the project area.
Terrace construction shortens slope length and reduces water velocity as it flows
down the mountain. The terraces were designed to hold surface runoff from a 2-inch
event, assuming no infiltration (Harbert,1992). The construction of flat terraces
helped reduce the direct discharge of runoff to the gulches, but also resulted in
indirect, negative effects. Bench terrace construction inevitably produced cut-and-fill
slopes that were steeper than the surrounding area. Subsurface mineral matter was
exposed at the cut-and-fill slopes, and the cut-and-fill slopes extended for significant
distances both upslope and downslope of the benches. These areas present some of
the greatest re-vegetation challenges.
Check Dams. As a secondary physical blockage to runoff, straw bales were to be
installed as check dams on the benches. Each check dam was to be keyed into the
slope using approximately 3 to 15 bales per dam in one to three layers, depending on
the specific installation. However, although terrace benches were installed, the
Pintlar did not install check dams in many areas. This led to channeled flow,
additional down-cutting of gullies, and in places, mass movement and sediment
discharges to streams. Down-cutting is especially severe along the western slopes of
Government Gulch and it results in significant discharge of sediment to Government
Creek and, eventually, the SFCDR.
As a result of this initial marginal stabilization effort by the PRPs, EPA and the State
began more extensive erosion control work in 1998 and 1999 after the government
took over the Site. In 1998 approximately 500 straw bale check dams, three to six log
pole toe-of-gully check dams, and 400 inner gully and toe-of-gully check dams were
installed along the hillside terrace benches. Additional work on check dam
installation was completed in 1999 including use of concrete "ecology blocks" at the
base of large gullies. These latter check dams are designed to withstand the larger
flow events occurring in the gullies. As a result, check dam installation work actually
extended the original plan of the PRPs by installing not only straw bale check dams,
but also larger dams within larger gullies. Check dam installations occurred in
Deadwood, Grouse, and Government Gulches.
The performance of each check dam will be evaluated regularly beginning in the
summer of 2000.
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Additional check dam structures were installed in the gulches and are evaluated in the
Section titled "Gulches".
B. Re-vegetation Programs
PRP-Implemented Re-Vegetation Programs. The Remedial Investigation (Dames &
Moore, 1990) identified 1,424 acres with from 0 to 25 percent vegetative cover; 1,697
acres with from 25-50 percent cover; and 8,873 acres with between 50 and
85 percent cover. Areas with less than 50 percent cover (3,121 acres) of the
11,994 acres studied or about 26 percent were targeted for re-vegetation. Much of
this acreage was planted by the PRPs with small tree seedlings prior to the
bankruptcy of the Site's primary PRP.
Between 1975 and 1982, the Bunker Hill Company planted approximately 2 million
tree seedlings over 2,290 acres of the Site. In 1990, under direction of the AOC,
Pintlar initiated a seedling planting program that extended from 1991 until 1994 when
Gulf (their parent company) declared bankruptcy. From May through June 1991,
Pintlar planted 140,000 tree seedlings on just under 300 acres and hydroseeded a total
of 45 acres. Pintlar also performed soil sampling and analysis for 1991 planting areas,
surface water sampling and meteorological monitoring.
In 1992 and 1993 additional tree planting was performed by Pintlar. Approximately
1,287 acres were scheduled to be planted in these 2 years, however because this effort
was not fully documented, it is uncertain how many acres or trees were actually
planted. And in 1994, Pintlar planted 100-400 trees per acre on 758 acres and 400-450
trees per acre on 215 acres.
EPA and State-Implemented Re-vegetation Programs. During the last 5 years, re-
vegetation by the government-lead project has primarily focused on re-vegetation of
the most highly denuded portion of the hillsides. This area, measuring 1,050 acres in
size, is an almost contiguous block of land located primarily within Government,
Deadwood, Magnet, and Grouse Gulches (Figure 2). This area is known as the
Hillsides Project Area. It consists of steep, terraced hillsides with acidic soils.
In 1996, EPA and the State planted 200,000 white pine seedlings in areas that had not
been planted by the PRPs.
In 1997, EPA and the State conducted an evaluation of the success of the planting
efforts conducted to date. Many of the trees planted by the PRPs and others were
found to have generated only a minimal amount of aboveground growth, particularly
within the hillsides project area. The acidic conditions, lack of nutrients and water,
rockiness of the soil, and steepness of the hillside slopes combine to make growing
conditions very difficult at the Site. As a result, much of the projected cover and
erosion protection from the trees has not been realized. In response to the difficult
growing conditions, the major re-vegetation activities since that time have focused on
establishment of grasses and forbs (herb-like plants) that, while protective of the hill
slopes, would not significantly compete with the trees in the long-term.
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To optimize re-vegetation approaches, demonstration test plots were installed in 1997
on some of the steepest and rockiest portions of the hillsides. The primary purpose of
the re-vegetation test plots was to evaluate the effectiveness of various soil
amendments, seed mixes, and hardiness of different plant species. The demonstration
plots were the initial step in the adaptive management approach to the hillsides
remedy, were evaluated after one growing season, and provided the necessary data to
optimize the initial larger-scale re-vegetation program conducted in the spring of
1998.
Information regarding EPA and the State's approaches and considerations regarding
hillside re-vegetation are presented in the Hillsides Re-vegetation Conceptual Plan
and Monitoring Plan (CH2M HILL, 1999). The plan presents a range of
cost-effective, technically feasible design solutions for re-vegetating the area of the
Site defined as "barren slopes" in the Non-Populated portion of the hillsides south of
1-90 (M, F, & G, 1992). The implementation of the design elements of this plan began
in the spring of 1998 when approximately 220 acres were limed at rates between 1
and 4 tons/acre. In the fall of 1998 that acreage was hydroseeded.
In the spring of 1999, EPA and the State limed an additional 700 acres of which 365
acres were subsequently hydroseeded in the fall. Additional liming and planting are
planned through 2001. The soil amendments are planned to consist of organic
matter, liming products, fertilizers, tackifiers, and seed mixes proven successful at
the demonstration plots. These products will be applied both from land-based
equipment and from the air. Beginning in 2000, hydroseeded areas will be evaluated
for percent cover and vigor. The project team will revisit those areas considered to be
unsuccessful and make decisions regarding new design solutions if needed.
C. Monitoring of Hillsides Performance
To ensure that the hillsides work meets the requirements of the ROD and overall
project goals, a monitoring program will begin in 2000. The Hillsides Monitoring
Program (Section 4.2.2) will measure suspended solids, flow, and turbidity in the
drainages affected by re-vegetated areas. This approach will be used to directly
determine the effect of the re-vegetation efforts on surface water quality. In addition,
percent cover of vegetation will be measured and the quality of that vegetation
assessed particularly with respect to its ability to regenerate naturally. Areas that do
not re-vegetate with current treatments will be analyzed and treated individually
according to the deficiency detected.
D. Selected Surface Armor or Soil Cover on Mine Waste Rock Dumps
The AOC (EPA, 1990) and AOC work plan describes the erosion control measures to
be undertaken at the Site at five mine rock waste dumps. The proposed action varies
between sites. Actual activities performed are described below; locations are shown
on Figure 2:
• Page Mine Waste Rock Dump. The AOC required five steps that were
generally accomplished for this site. The remedy was performed by ASARCO
in 1992. They demolished and removed the foundations from the mill
buildings and buried them under the waste rock pile as it was flattened and
recontoured to more closely match the natural topography. No information
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was found about the actual finished slopes of the waste pile. A shot-creted
spillway channel was constructed down the face of the dump to carry Silver
Creek in the event of a flood where the flow exceeds the capacity of the
existing buried culvert. The spillway appeared in good condition at the end of
1999.
Six inches of clean soil was placed over the regraded mine dump. The area
was then hydoseeded and planted with trees. Presently, the trees planted
appear to be in good condition and a minor amount of secondary vegetative
growth has established under the trees. There has been no evidence of
erosion of the waste rock pile itself. In general, the system appears to be
performing adequately; however, it is recommended that the area be
reviewed to evaluate the need for additional efforts to encourage further
vegetative growth.
Silver Bowl Waste Rock Dump. The AOC work plan required sampling and
analysis of the soil at the site to determine appropriate soil amendments
needed to enhance plant growth. Pintlar regraded the area in 1992. The area
has been re-vegetated at least three times without success. The first time the
plants survived two seasons with declining vigor, but had died by the third
season. The area was limed and hydroseeded in 1998 and 1999 and is
included in the current conceptual plan for re-vegetating the Magnet Gulch
area.
• Arizona Tunnel Waste Rock Area. In 1998 and 1999, the Bunker Limited
Partnership (BLP) removed the Arizona Tunnel waste, rock pile from
Deadwood Gulch and disposed the rock on the CIA. Following regrading of
the affected Deadwood Gulch area, BLP lined the drainage channel with rock
and limed and hydroseeded the riparian area adjacent to the creek.
Sierra Nevada Mine Waste Rock Dump. Pintlar removed this waste rock
pile from Deadwood Gulch except for approximately 4 to 5 feet of rock
remaining on the valley floor. They then graded the dump into the hillside and
re-vegetated it. Additionally, the BLP has performed restoration work above
and below the rock dump area in Deadwood Gulch which consisted primarily
of creek stabilization efforts, placing in-stream boulders to dissipate energy,
and re-vegetation programs.
Wardner and Smelterville Slope Stabilization Plan. The AOC discussed
the fact that erosion of barren hillsides affected a number of residences in both
towns. The document called for a detailed study and plan to be submitted by
1991. While a formal plan has not been prepared for this work, cribbing and
gabion retaining structures were constructed (Pintlar, 1992). Pintlar installed
approximately 160-linear feet of cribbing and 450 feet of gabion wall at the
slope toe in Smelterville. In 1997, EPA and the State performed additional
hillside stabilization at the base of the Smelterville hillside that consisted of
cleaning out sloughed soils, reinforcing existing catchment walls, and
constructing additional gabion walls to prevent sloughing soils from entering
remediated yards. In 1992 in the town of Wardner, Pintlar Corporation
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constructed approximately 380 linear feet of cribbing along the toe of hillside
slopes adjacent to remediated yards. During the summer of 1999, the
USACE's infrastructure contractor restored capacity behind existing cribbing
in Wardner by removing accumulated sediment and rock. Also in 1999,
various isolated small mine dumps were removed from the hillside above
Wardner by BLP.
E. Enforce Existing Controls on Access
Controls of access to the hillsides currently consist of locked gates across
Government Gulch Road and gates across a closed portion of McKinley Avenue. The
general public cannot drive up to the hillsides area from the northern portion of the
site. However, long-term access restrictions are recommended to be evaluated,
especially after McKinley Avenue is re-opened to the public.
F. Maintain Existing Fencing
The hillsides area is generally not fenced with the exception of a few hillside road
crossings where access is limited and controlled.
G. Some or all of the Solid Waste Landfill Material May Be Relocated to the
Lead Smelter Closure. Contour and Re-vegetate Disturbed Areas.
Solid waste from the lower Industrial Landfill east of Deadwood Gulch (Figure 2)
was removed to the CIA in 1998. Solid waste from the upper Industrial Landfill is
planned to be excavated and disposed at the Borrow Area Landfill after its
completion.
H. Surface Water Flows at the Solid Waste Landfill Will Be Returned to
Their Natural Conditions to the Extent Practicable
EPA graded the removal area of the lower Industrial Landfill to match existing
contours. Capping was not thought necessary since the waste was removed and was
not process-related and not considered hazardous. The upper landfill is planned for
removal in the fall of 2000.
4.3.1.4 Hillsides Operations and Maintenance Considerations
In the short-term, operations and maintenance will be guided by the Hillsides Monitoring
Program (Section 4.2.2). This program will monitor the performance of the particular
elements of the Hillsides re-vegetation and stabilization activities. The results of the
monitoring will be reviewed annually by the project team in order to remedy any problems
with achievement of the goals and objectives of the remedy.
For the long-term, operations and maintenance for the hillsides stabilization and re-
vegetation is expected to include continued monitoring for surface erosion and repair of rills
if needed, cleaning out ditches and culverts on roads near slopes, inspecting check dams
and repair if necessary. Vegetation should be sustainable and only need to be replaced or
repaired if erosion or mass movement disturbs it in a manner that could result in
degradation of the human and/or natural environment.
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4.3.1.5 Assessment of Remedial Actions
A. Evaluate Remedy Performance
1. Erosion Control Structures
The installation of both bench terraces and check dams was completed in
accordance with their respective designs in 1999. EPA and the State will measure
performance of current check dams beginning in 2000. Consequently, this portion
of the hillsides project is too immature to make any statements specific to
performance.
2. Re-vegetation Programs
This remedial activity is in progress. Earlier tree planting efforts by the PRPs
were very successful in areas north of 1-90. However, within the hillsides project
area, seedling success was thought to be marginal due to the slow growth of
seedlings planted. More recent observations, however, suggests that although
slow growth initially occurred, the trees may have been concentrating growth on
root structures that will support above ground growth when sufficient water and
nutrients are obtained. The current adaptive management approach being
implemented by EPA and the State focuses on the performance of the vegetation
with built-in repair activities when needed. This approach is expected to address
potential issues, problems or failures that may occur. Initial performance, while
premature, indicates potential for successfully covering the hillside ground
surfaces with vegetation sufficient to contribute to the goal of controlling erosion
and increasing infiltration.
3. Surface Armor Or Soil Cover On Selected Mine Waste Rock Dumps
All of these sites received treatments more protective of the goal to control direct
contact or erosion hazards, than was called for in the AOC. The PRPs and EPA
removed most of the waste rock-at these sites which provides for a more long-
term treatment of the contaminants at these locations the regrading and capping
remedies that had previously been planned. Additionally, the sites either were
re-vegetated or are scheduled for re-vegetation as part of the general re-vegetation
on-going at the site. Re-vegetation is likely to be a more long-term and
sustainable treatment than a layer of soil or rock.
In addition to the sites named in the AOC and the ROD, four other waste rock
piles were removed. Two mine dumps located on the Wardner hillsides (Figure
2) were removed by BLP in 1999 and disposed in the Guy Cave depression in the
Milo Creek Basin. These two mine dump areas were regarded for drainage and
sprayed with tackifier. The third mine dump removed is the Wyoming Mine
Dump in Grouse Gulch (Figure 2). BLP funded removal of waste rock adjacent to
the creek. The area was re-sloped and the creek bed stabilized using rock to armor
the ranks and as check-dams across the creek profile. New sedimentation basins
were also constructed and sediment that had deposited behind existing gabion
dams was cleaned out. EPA and the State re-vegetated the area in 1998. A fourth
tailings pile was removed from the old mill site on Grouse Gulch to the CIA. The
area was also regraded and re-vegetated.
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4. Wardner and Smelterville Slope Stabilization Plan
Cribbing was minimally to moderately successful in controlling erosion above
the towns of Wardner and Smelterville. For both of the hillsides, a portion
consists of weathered bedrock outcrops that naturally ravel. This raveling of rock
and soil is a continual natural process that cannot be cost-effectively controlled.
Gullies from the hillsides occasionally deposit sediment on resident property
located at the base of both the Wardner and Smelterville hillsides. Recent
analyses of soil samples from the Warder and Smelterville hillsides were an
average of 5633 mg/kg and 4555 mg/kg lead, respectively (TerraGraphics, 2000).
Since these hillside contamination levels are above the 1,000 mg/kg action level
for yard cleanups, it is important that sloughing from these hillsides be contained
at the base of the slopes such that yards are not recontaminated. Periodic clean
out behind soil catchment walls will be necessary on an as-needed basis.
In general, the potential for mine dumps to erode and impact the protectiveness
of the Populated Areas of the Bunker Hill Site is considered in the Bunker Hill
Populated Areas Operable Unit First Five Year Review Report. That document
concludes that no further action is warranted on mine dumps at this time from a
human health perspective.
For information on the impact of hillside sloughing on the protectiveness of the
Populated Areas of the Bunker Hill site, refer to the Populated Areas Five Year
Review Report. That document identifies areas where sloughing may be
recontaminating clean portions of the Populated Areas. In addition, that
document also discusses the need for local planning and zoning changes so that
future development efforts on, or at the base, of hillsides do not result in further
recontamination.
5. Enforce Existing Controls On Access
This activity is ongoing and provides some means of controlling or limiting
contact with contaminants in the area. Some isolated reports have been received
that the Grouse Gulch hillsides are being used by trail bikers. Should these types
of uses continue, existing access controls may need to be enhanced to limit
uncontrolled use.
6. Maintain Existing Fencing
This activity is ongoing and provides some measure of controlling or limiting
direct contact with any contaminants that may be in existence in those areas.
7. Some or all of the Solid Waste Landfill Material May Be Relocated to the
Lead Smelter Closure. Contour and Re-vegetate Disturbed Areas.
Solid waste from the lower Industrial solid waste landfill east of Deadwood Gulch
was removed to the CIA in 1998. The area was regraded and hydroseeded. This
treatment is believed to be protective since the waste removed was not considered
hazardous.
8. Surface Water Flows At The Solid Waste Landfill Will Be Returned To
Their Natural Conditions To The Extent Practicable
The removal area of the lower landfill was regraded and hydroseeded to match
existing contours which should bring surface flows to nearly original condition.
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As noted in Section 4.3.1.3 H, the upper landfill is planned to be removed in the
fall of 2000.
B. New Information
The workshop process discussed above approved the use of adaptive management
for making decisions about short and long-term management of these steep areas. By
default, this process will continually introduce and discuss new information about the
performance of the hillsides in order to determine appropriate new approaches for
repairing any failures that may occur.
The results of agency workshops (Appendix B) restated some of the ROD
suggestions for remedial activities for the hillsides re-vegetation work. As such, these
modifications will be evaluated to determine if an ESD or ROD amendment is
necessary to document changes to performance standards.
C. Identify Deficiencies
None were found.
D. Recommend Improvements
1. Evaluate whether additional restrictions to site access are to prevent direct
contact with contaminants.
2. Periodic inspection and, if necessary, removal of sloughed soil and rock from
behind catchment walls in Smelterville and Wardner is recommended to prevent
recontamination of remediated yards that are located at the base of hillsides in
these communities.
3. Evaluate the need for additional efforts to encourage vegetative growth at the
Page Mine waste rock dump.
4.3.2 Gulches Remedial Actions
4.3.2.1 Introduction and Background
As discussed previously, the Bunker Hill Superfund site is located in the Silver Valley of the
SFCDR. This steep, mountain valley trends east to west with numerous smaller creek eroded
valleys or gulches running south to north primarily on the south side of the-valley. The seven
gulches of primary concern cited in the ROD for remedial actions are from west to east
(Figure 2):
Grouse Gulch,
Government Gulch,
Magnet Gulch,
Deadwood Gulch,
Railroad Gulch,
Portal Gulch, and
• Milo Gulch.
Railroad, Portal, and Milo Gulch remediations are discussed in Sections 4.3.7, 4.3.8, and
4.3.11 respectively, rather than this section. These three gulches are discussed separately
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because their contaminant source issues and required remedial approaches differed from the
other gulches, specifically:
Railroad Gulch: included with Boulevard Area discussions because its creek crosses
the Boulevard property (refer to Section 4.3.7).
Portal Gulch: ROD-required actions focus on mine water treatment from the Bunker
Hill mine whose portal is located in Portal Gulch (refer to Section 4.3.8).
Milo Gulch: major water piping project with multiple agency involvement and
stabilization of existing mine landing area (refer to Section 4.3.11).
The remaining gulches discussed in this section (Grouse, Government, Magnet and
Deadwood) focus on similar contaminant issues and similar remedial approaches (source
removal actions and rebuilding/ stabilization of creeks). As noted in Section 4.3.1, the ROD
and this 5-year review distinguish between the term "hillsides" and "gulches". For both of
these documents, the gulches include the flat portions of the gulches and not the upward
sloping hillsides.
A. Grouse Gulch
Grouse Gulch is a small watershed located west of Government Gulch with a
perennial creek (Grouse Creek) that courses through the Smelterville city limits. Past
mining activities; sparse hillside vegetation, and relocation/ confinement of the creek
channel have all contributed to an unstable creek profile and alignment that continues
to erode and convey sediment into Smelterville. Following a major flood event in
1986, Shoshone County and the Soil Conservation Service constructed four gabion
dams across the creek at various locations along its length in an attempt to stabilize
the creek bed profile. Past smelting and mining activities have resulted in surface
contamination of the soils in the gulch area, including point sources of a mine dump
and an abandoned tailing pile. These contamination sources and the unstable and
eroding creek contributed to contaminated sediment being carried downstream,
especially during high flow runoff events. Prior to remediations conducted in Grouse
Gulch, the City of Smelterville was particularly concerned that if Grouse Creek
flooded during high flow events that several remediated yards within Smelterville
could be recontaminated.
B. Government Gulch
Government Gulch, the largest gulch on site, is also the historic location of several
ore processing facilities. The Zinc Plant operated in Government Gulch from 1928 to
1981. Two sulfuric acid plants were constructed at the Zinc Plant in 1954 and 1966.
A phosphoric acid plant was added in 1960 and a fertilizer plant was added in 1965.
The Zinc Plant complex also housed a silver refinery, and mercury and cadmium
processing units. A cobalt storage structure was located just upstream of the zinc
plant. Several wastewater ponds (typically unlined) were also located in this gulch.
A significant amount of mine waste-rock and other random fill (up to 10-feet thick)
was placed across the valley since the early 1900's in order to increase the foundation
elevation of the processing facilities as well as to provide an easy means of disposing
mine waste materials from processing. As a result, during the RI, much of the
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subsurface soils were found to be highly contaminated to about 10-feet in depth
especially in the industrial parts of the gulch.
Government Creek, which historically flowed down the center of the gulch in a
meandering pattern, was modified during the time of active ore processing. Above
the Zinc Plant, Government Creek remained in a somewhat natural, unlined surface
water channel, but was routed to flow through the zinc plant reservoir to serve as a
water source for processing. From the Zinc Plant reservoir, Government Creek was
then hard-piped to the western side of the gulch where it discharged into a shot-crete
lined channel that flowed north past the Phosphoric Acid Plant. Once past the
Phosphoric Acid Plant, Government Creek flowed back to the center of the gulch into
the original natural channel. Government Creek then crosses under McKinley Avenue
and continues to flow north before crossing under 1-90 and discharging into the
SFCDR. As part of EPA's 1990 AOC with Gulf Resources and Hecla Mining,
sediment retention gabion dams were constructed in Government Creek upstream of
the Zinc Plant to settle sediment from surface water prior to its continued
downstream flow.
C. Magnet Gulch
Magnet Gulch, located to the east of Government Gulch, was used for various
material storage and handling processes. The 13.5 acre A-4 gypsum pond located at
the base of Magnet Gulch was impounded by a waste rock embankment on the north
to store waste gypsum from the phosphoric acid/fertilizer plant. Above this feature a
roadway embankment was constructed to enable rail transport of concentrates and
ores from the mill concentrator and railroad facilities to the Smelter Complex. Later
McKinley Avenue was constructed between the A-4 gypsum pond and the railroad
grade. This railroad embankment impounded surface water from the gulch and
formed McKinley Pond. Upstream of the railroad embankment, Magnet Gulch was
filled with waste mine rock to create a storage area for smelter process by-products.
This location was used to store copper dross flue dust amongst other materials. The
copper dross flue dust was eventually consolidated in the principal threat materials
disposal cell at the smelter closure landfill. Further upstream, a third embankment
was constructed across Magnet Gulch to create the initial impoundment for waste
gypsum, the A-l pond.
With the infilling of much of Magnet Gulch to construct the A-l gypsum pond,
railroad embankment/ materials storage area, and the A-4 gypsum pond, the seasonal
flows of Magnet Creek were displaced from its natural channel and put into a buried
4-foot by 4-foot box culvert. The box culvert discharged into McKinley Pond (Figure
2) which tended to seep into the subgrade soils and through the A-4 gypsum pond
prior to discharging as seeps through the northern A-4 embankment and into Bunker
Creek. Additional creek stabilization work, primarily a sediment retention gabion
dam, was constructed in 1992 as part of EPA's 1990 AOC with Gulf Resources and
Hecla Mining.
Much of the native vegetation in Magnet Gulch and surrounding hillsides had been
significantly adversely impacted by smelter emissions resulting in substantial
surface erosion within the gulch (McCulley, Frick & Gilman, 1996).
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D. Deadwood Gulch
Deadwood Gulch is located immediately east of Magnet Gulch. As Deadwood Creek
leaves the gulch area, it flows beneath McKinley Avenue between the eastern edge of
the A-4 Gypsum Pond and the Lined Pond prior to discharging to Bunker Creek. As
a result of mining-related activities, the Deadwood Gulch corridor has also been
substantially impacted from its natural state. Including having the Arizona Mine
dump totally block the gulch in the upper reaches, having vegetation destroyed by
emissions and logging resulting in severe erosion and sediment transport, and
destabilization of the Deadwood Creek channel because of high flows. To lessen the
impacts of some of these adverse conditions, in the early 1990's as part of EPA's 1990
AOC, Pintlar built two gabion dams across Deadwood Creek for sediment retention.
The intent of these sediment dams was to slow down flow during spring run-off such
that sediment could be retained within the gulch rather than flowing into downstream
water systems. In the spring of 1994, the northernmost gabion dam was damaged by
extensive spring run-off Water had built up behind the dam and undermined the
dam's soil foundation causing settlement across the crest of the gabion dam as well as
damage and shifting of the downstream apron of the dam. A clogged filter fabric on
the upstream face of the dam, that apparently caused the dam to fail and overtop, was
removed. Removal of the filter fabric allowed free flow of water through the dam in
high flow conditions and re-established the necessary stability of the dam. The dam
continues to perform adequately, and will be routinely inspected after major storms
and during annual inspections.
4.3.2.2 Review of ROD, ESD, & ROD Amendment
Table 4-4 summarizes ROD and ESD requirements for the various gulch remedial actions
discussed within this section. The ROD requirements for the gulches were cited amongst
several general sections of the ROD rather than being summarized by specific gulch. For
clarity purposes in comparing with the ROD, the ROD requirements are summarized as
contained within the ROD versus by gulch.
Table 4-4
Gulch Remedial Actions
ROD Requirement
Remedial Action Objective/Goal
Document
1. Erosion control structures and
sediment basins in Deadwood,
Magnet and Government Gulches
Reduction of suspended sediment/contaminant
loading in surface runoff to the SFCDR
Oct 1990 AOC
ROD 9.2.1
2. Institutional controls
Limit direct contact with contaminants
ROD 9.2.1
3. Enforce existing controls on access
Limit direct contact with contaminants
ROD 9.2.1
4. Maintain existing fencing
Limit direct contact with contaminants
ROD 9.2.1
5. Rock and/or soil barrier on A-4
Gypsum Pond or relocate to CIA
Limit direct contact with contaminants and control
migration of contaminants to surface and
groundwater; Minimize infiltration through the
gypsum material
ROD 9.2.5
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Table 4-4
Gulch Remedial Actions
ROD Requirement
Remedial Action Objective/Goal
Document
6. Temporary dust control on material
accumulation sites
Control migration of windblown dust
ROD 9.2.1
7. Channelize and line Government Creek;
A natural stream channel will be
developed from the upper reaches of the
gulch down
to Bunker Creek
Streambed excavation goals (ESD 4-98)
Pb - 1,000 mg/kg; As - 850 mg/kg; Zn - 1,000 mg/kg; Sb
- 850 mg/kg; Hg - 850 mg/kg; Cd - 850 mg/kg - Soils
above these contamination levels will be placed in the
Lead Smelter Closure.
ROD 9.2.1/
ESD 12-95/
ESD 4-98
8. Contaminated materials from the Zinc
plant and Phosphoric Acid plant areas will
be placed in the Lead Smelter Closure.
Reduce potential groundwater loadings from these
sources
Upland (gulch areas outside the stream banks)
excavation cleanup goals (ESD 4-98)
Pb - 10, 000 mg/kg; As - 850 mg/kg; Zn - 9, 000 mg/kg;
Sb - 850 mg/kg; Hg - 850 mg/kg; Cd - 850 mg/kg - Soils
above these contamination levels will be placed in the
Lead Smelter Closure.
ROD 9.2.5/
ESD 12-95/
ESD 4-98
9. Place cutoff wall in upper Government
Gulch to divert clean water away from
contaminated areas; place cutoff wall in
lower Government Gulch to collect
groundwater for treatment in the collected
water wetland.
Minimize contamination to SFCDR
ROD 9.2.5
10. Re-vegetate disturbed areas
Minimize erosion
ROD 9.2.5
11. Relocate A-1 Gypsum pond to CIA. A
portion of this material pile will be
relocated from.Magnet Gulch to the Lead
Smelter Closure.
Limit direct contact with contaminants and control
migration of contaminants to surface and groundwater;
Minimize infiltration through the gypsum material
ROD 9.2.5/
ESD 12-95
12. Install barriers consistent with land-use in
remaining areas (a minimum of 6" of
clean soil or other barrier will be installed
if
surface concentrations >1000 mg/kg Pb)
Minimize direct contact with contaminants
ROD 9.2.5
13. Permanent dust control through
containment, "hot spot" removal, soil/rock
barriers and re-vegetation
Minimize contaminant migration and direct contact risk
ROD 9.2.6
4.3.2.3 Description of Remedial Actions Conducted at the Site
A. Grouse Gulch
The overall goal of the Grouse Gulch remedial action was to minimize further
contaminated sediment transport down the gulch and thereby reduce the potential for
recontamination of previously remediated areas within the city of Smelterville and
sediment load into downstream river systems.
To achieve these goals, the following work was conducted:
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Approximately 1,200 cubic yards of tailings above the uppermost gabion
structure were removed from locations closest to the creek and disposed in
the CIA.
A new gabion dam was constructed in the lower reaches of the gulch to
increase sediment retention time and to augment the sediment retention
capacity of the existing gabion dam system in the gulch.
Sediment that had built up behind existing gabion dams was removed to
provide more capacity for future runoff events.
The Wyoming mine dump located near the creek was buttressed at its base to
minimize the potential for erosion into the creek. To increase its stability,
approximately 2,000 cubic yards of mine dump material was removed and
disposed at the CIA.
Accumulated sediment and alluvium was removed from downstream portions
of the creek within the Smelterville city limits to increase the flow capacity
within this portion of the creek and to minimize the potential for overtopping
into remediated yards.
Access roads up through the gulch were improved to enable easier O&M of
the gabion retention structures.
The Grouse Gulch remedial action was implemented in the summer of 1997 using
BLP bankruptcy funds.
B. Government Gulch
Those components of the Government Gulch remedy that relate directly to the
demolition of facilities located in the gulch are discussed in Section 4.3.6, Industrial
Complex Remedial Action. The remedial actions discussed in this section focus on
source removal measures and controlling migration of contaminants to surface and
groundwater.
As part of EPA performing remedial actions at the Site, implementation strategies
were developed to increase the quantity of source removals (approaches believed to
have a greater positive effect on health and the environment) and also defer some
aspects of remedies that appeared to have a low certainty of success or a narrow
cost-benefit margin. For the Government Gulch remedial action, this specifically
meant that:
• Tailings removal quantities were significantly increased (about two-fold)
over those removal quantities estimated in the Feasibility Study (FS) and the
ROD.
• In light of the increased source removal action, EPA and the State chose to
defer construction of the ROD-specified groundwater cutoff wall located up-
gradient of the Zinc Plant and the groundwater collection wall located down-
gradient of Phosphoric Acid Plant. These groundwater control and collection
systems are part of the long-term constructed wetland water treatment
remedy described in the FS and the ROD for the Smelterville Flats area
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(Section 4.3.3). As discussed in Section 4.3.3, long-term water treatment and
the constructed wetland treatment technology is also being deferred until the
benefits of the large-scale source removal actions can be evaluated. If further
treatment is determined to be necessary, additional remedial measures will be
evaluated. In addition, if monitoring data indicates that the source removal
actions are effective in improving surface and groundwater quality, the need
for either an ESD or ROD Amendment will be evaluated to delete the ROD
requirement for groundwater control and collection systems.
• Because of the large-scale source removal action in Government Gulch, EPA
and the State chose to defer lining Government Creek to reduce infiltration
into what was to be, under the FS approach, contamination left in-place. The
large-scale source removal action resulted in EPA and the State deciding to
reconstruct Government Creek as a 'natural channel'. The need for either an
ESD or a ROD Amendment will be evaluated to address the ROD
requirement to line Government Creek.
From 1996 through 1998, the Government Gulch remedy was implemented. This
remedial action consisted of the following work components:
• Soil Removal Action: Nearly 700,000 cubic yards of contaminated materials
(tailings, waste rock, and PTMs) were removed from the gulch extending
from the upper reaches of Government Gulch down to McKinley Avenue. As
noted previously, the "gulch area" is defined as the flat valley-bottom of the
gulch, exclusive of the hillsides. This quantity of removed material is over
twice the amount of contaminated material that was projected to be removed
under the remedy planned in the FS and ROD. Within the area of the creek
channel, contaminated soil greater than 1,000 mg/kg lead was removed up to
a maximum depth of 3 feet below the channel and then backfilled with clean
borrow. Outside the creek channel and extending to the upward slope of the
hillsides, soils with lead concentrations greater than 10,000 mg/kg were
removed. The entire gulch area received a 6-inch barrier cap of clean soil (less
than 100 mg/kg lead) typical for future industrial use. Verification testing of
all removal areas was conducted by the site removal verification team (RVT)
(representatives of EPA, the State, and the US ACE).
• Reconstruction of Government Creek: Government Creek was
reconstructed from the upper reaches of the gulch up to approximately 2000
feet south of McKinley Avenue. Plans are in place to continue reconstruction
of Government Creek from McKinley Avenue to 1-90 where it flows into a
culvert system under the highway in order to discharge into the SFCDR. The
low flow channel of Government Creek was sized to handle a 25-year storm,
with an enlarged channel section to handle the 100-year storm. The low flow
channel was typically rock-lined; the flood plain channel was vegetated.
Concrete and riprap grade control structures were constructed intermittently
along the creek profile at major changes in grade.
• ICP Capping and Re-vegetation: A 6-inch clean soil ICP barrier cap was
placed outside the channel floodplain area. The entire gulch area was then
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hydroseeded, with the exception as noted above for the rock-lined low flow
channel of Government Creek. Willows were planted in riparian areas of the
creek.
C. Upper Magnet Gulch - Government-Implemented Action
Similar to Government Gulch, the primary objectives of the upper Magnet Gulch
remediation were to focus on increased source removal actions and reconstruction of
natural surface-water flow channels. The Magnet Gulch remediation implemented by
EPA and the State included:
• A-l Gypsum Pond Removal: Conducted in 1995 and 1996, this action
removed the gypsum and the A-l embankment and consolidated these
materials at the CIA and the Smelter Closure area.
• Removal of Mid-Gulch Fill Materials: The mid-gulch area below the A-l
gypsum pond was removed in 1997 to 1998. As noted above, this area of the
gulch was infilled to provide material storage areas for processing byproducts
and to provide space for the railroad line to the Smelter. These contaminated
gulch materials were removed and consolidated in the Smelter Closure area.
The EPA and State removal verification team (RVT) verified that soil removal
levels had been achieved. Approximately 200,000 cubic yards of material
were removed. In addition, the box culvert that the mining companies had
constructed beneath the mid-gulch fill to carry the flows of Magnet Creek was
located and removed.
• Reconstruction and Re-vegetation of Magnet Creek: In 1999, the portion
of Magnet Creek above McKinley Avenue was reconstructed on native
material after the source removal actions had been conducted. Because of the
steepness of Magnet Gulch, erosion of the newly constructed channel was a
concern resulting in three sediment retention basins being constructed along
the creek's alignment to slow down water flow. The channel and banks were
rock-lined to minimize erosion. Magnet Gulch was hydroseeded upon
completion of the channel work.
D. Lower Magnet Gulch, Partial Removal and Capping of A-4 Gypsum Pond -
PRP Implemented Action
The lower portion of the Magnet Gulch remedial action is being performed by a PRP
(Stouffer Chemical) and has not yet been completed. The ROD states that the A-4
impoundment in this area will either be capped in-place, partially, or completely
removed as long as water quality performance standards are achieved. Initially,
PRPs planned achieve the ROD requirements and close the gypsum impoundment
by grading, capping, and re-vegetating the surface of the A-4 pond to control erosion
and infiltration. Magnet Creek was routed over the top of the closed pond surface
through a geomembrane-lined channel. This channel discharged surface water
through a drop structure, constructed on the face of the northern A-4 embankment,
and into Bunker Creek. Surface water entered the new geomembrane-lined channel
through a culvert extending beneath McKinley Avenue from McKinley Pond. In
order to minimize seepage from McKinley Pond through the McKinley Avenue road
fill, the design included a geosynthetic cutoff barrier extending along the southern
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perimeter of pond between McKinley Avenue and McKinley Pond. Other identified
performance standards associated with the remedial action include:
The areas adjacent to the channel are required to be graded such that final slopes are
not less than two percent nor greater than 5 percent.
The total thickness of the closure cover for Pond A-4 is required to be not less than
12 inches, including a minimum of 6 inches of clean topsoil overlying a minimum
of 6 inches of grading fill.
The channel and appurtenant works are required to be sized to convey the 100-year,
24-hour storm event.
The re-vegetation of the A-4 closure area is required to achieve an 85 percent
coverage within 3 years following planting.
The surface capping and channel construction was completed as initially designed in
1997. However, shortly after the channel was placed in service, leakage into the
underlying gypsum material through the geomembrane-lined channel was
observed. The Magnet channel leakage and subsequent formation of solution cavities
along the channel alignment resulted in additional failures of the geomembrane
channel liner. To address this issue and provide a long-term solution, the PRP
proposed an alternative channel design that involves establishing the base of the
channel on the underlying native valley, soils. The agencies approved the conceptual
redesign in a letter to the PRP dated January 5, 1999.
During the redesign of the Magnet Gulch channel, the agencies expressed concerns
regarding potential long-term gypsum dissolution resulting from groundwater
seepage through the existing pond subgrade. In response to this concern, a series of
supplemental studies were conducted by the PRP to establish a water quality
monitoring program and to evaluate the effectiveness of the proposed remedial
efforts regarding the closure of the A-4 impoundment. The studies included
geochemical modeling of groundwater and an evaluation of impacts associated with
flood events in Magnet Gulch. Agency comments on these studies focused on
concerns regarding the ability of a proposed gravel toe drain to control seepage
along the base of the A-4 embankment. This gravel drain is to extend approximately
600 feet along the toe of the embankment and is designed, with the use of a
geotextile fabric, to control erosion and route collected groundwater into the new
Magnet Gulch channel.
In September 1998, excavation activities were initiated to lower the Magnet Gulch
channel down to the native soil at the floor of the impoundment. Along the initial
channel section, adjacent to McKinley Road, the channel bed was sloped steeply
through the exposed gypsum materials (approximately 30 to 40 feet vertically)
before encountering the underlying native soils. The channel excavation extends to
depths of over 40 feet. Side-slopes were graded to 2.5H:1V resulting in a surface
opening in excess of 200 feet. Excavation activities were halted in December 1998 due
to inclement weather. At that time, the channel excavation was complete with the
exception of the lower most portion of the channel cut through the north
embankment. In this area, the excavation was terminated at an elevation
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approximately 10 feet above the floor of the impoundment, leaving a plug of soil in the
bottom of the channel. The plug restricted surface water flows and resulted in
the ponding of water within the channel. As a protective measure, a temporary
culvert was placed as an overflow pipe. Monitoring of this area indicated that the
overflow was never used, as the rate of surface water inflow in the channel reached
equilibrium with the rate of infiltration through the plug.
During the 1999 summer construction season, the soil plug was removed and the
channel excavation completed. Remedial action work still to be completed at the site
includes: 1) the armoring of the new Magnet Gulch channel between McKinley
Avenue and Bunker Creek, 2) the construction of surface water control channels and
appurtenant works on the surface and around the perimeter of the A-4 pond, 3) the
construction of the toe drain to protect the pond's perimeter embankment,
4) placement of 12 inches of clean soil over the Magnet Channel side slopes, and final
soil cap placement and seeding of the soil cover system.
E. Deadwood Gulch
Deadwood Gulch, located to the east of Magnet Gulch, has historically had the lowest
levels of contamination in its surface water compared to the other major gulches at the
Site. This was thought to be a result of the relative lack of industrial mining activity
that took place in Deadwood Gulch in comparison with Government and Magnet
Gulches. The Arizona Mine dump filled the narrow valley of Deadwood Gulch it its
upper reaches. In addition to the Arizona Mine Dump, various mine adits/portals
surfaced in Deadwood Gulch that occasionally discharged groundwater seepage. Other
than these point sources of contamination, Deadwood Gulch contamination was
primarily from the erosion of adjacent hillside soils that had become contaminated
with smelter emissions. The Arizona Mine Dump that blocked the upper reaches of
Deadwood Creek also resulted in significant quantities of rock bed load being
transported downstream during run-off events.
To address the levels of contamination and the erosion damage in Deadwood Gulch,
the following remedial actions were conducted:
Gabion Dam Sediment Removal: In 1995 and 1996, sediment that had
collected behind the gabion dam retention structures was removed. The
sediment was tested for contaminant levels and was found to be below
cleanup goals enabling the sediment to be spread out along areas outside the
creek bed and then hydroseeded. Since erosion continues in Deadwood
Gulch, it is anticipated that periodic sediment removal behind the gabion
dams will likely be required until the hillside re-vegetation and the creek
stabilization efforts become more stable.
Creek Stabilization: Creek stabilization work was conducted in 1998 using
BLP remediation funds. The activities consisted of constructing small cobble
and boulder grade check dams perpendicular to the creek flow about every
200 to 300 feet. The purpose of the check dams was to slow stream flow
down, to drop out sediment/bedload, and to minimize erosion of creek
banks on meander curves. Typically the check dams were 1.5 to 2 feet high, a
couple feet wide, and spanned perpendicularly across the channel.
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• Removal of Arizona Mine Dump: The Arizona Mine Dump was removed
and hauled to the CIA for disposal in 1997 and 1998. Approximately 500,000
cubic yards of material was removed such that a reconstructed streambed
could be constructed in the previously blocked portion of Deadwood Gulch.
The mine waste rock removed to the CIA was put to beneficial use as haul
road surfacing on top of the CIA.
Lower Deadwood Creek Reconstruction: Lower Deadwood Creek from the
first gabion down to a sedimentation basin just south of McKinley Avenue
was reconstructed in 1996 and 1997 using the BLP remediation fund. New
culverts were installed under McKinley Avenue in lieu of the existing under-
sized box culvert. A site PRP (Stauffer Chemical) constructed a heavy riprap
channel from the north side of the McKinley Avenue culvert down to Bunker
Creek in the steep portion between the A-4 Gypsum Pond and the Lined Pond.
4.3.2.4 Operations and Maintenance Considerations
The O&M manual for the gulches discussed in this section is in the process of being
developed by IDEQ. However, some maintenance issues that should be expected include:
Seasonal inspection and clean out of culverts and gabion dams.
Inspection and repair, if necessary, of creek beds for erosion, piping around riprap,
and grade structures.
Inspection and cleanout of sedimentation ponds and disposal of sediments.
Inspection and repair, if necessary, of vegetated areas.
Inspection and repair, if necessary, of caps.
4.3.2.5 Assessment of Gulch Remedial Actions (Grouse, Government, Magnet,
Deadwood)
A. Remedy Performance
Remedy performance for the gulch actions can be judged based on whether the
remedy satisfies the following intent of the ROD and ESD documents:
Stable non-eroding surface water channels
Contaminated soil either capped or removed such that migration to surface and
groundwater is substantially minimized
Vegetation reestablished sufficiently such that surface water runoff will not
erode caps
A sufficient amount of contaminated source material removed such that
groundwater contamination levels decrease with time.
At this time, none of the gulch remedial actions have been completed for more than
1 or 2 years, such that it is premature to judge whether remedy performance has
been achieved. In addition, in many areas, additional actions are still required (i.e.,
riparian plantings for most gulches).
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It is however recommended that routine surveys be conducted to evaluate channel and
cap stability, success of vegetation, and surface water and groundwater quality. These
surveys will then provide data for the next 5-year review.
B. New Information
No new information became evident during this 5-year review.
C. Identify Deficiencies
No deficiencies were evident during this 5-year review. Some components of the
remedy have not yet been initiated (e.g., riparian planting of Government and
Deadwood Gulches), however, this is not considered a deficiency.
D. Recommended Improvements
No improvements to the gulch remedies are recommended at this time.
4.3.3 Smelterville Flats Remedial Action
4.3.3.1 Introduction and Background
Mining companies constructed the first mill at the Bunker Hill Complex in 1886 to process
locally mined lead, zinc, silver and other metals. Metals processing expanded and continued
until 1981. Before the widespread use of ponds to contain tailings, mining companies often
disposed of tailings on the valley floor and in local surface waters. The SFCDR received
tailings in this manner from numerous mines and mills in the Silver Valley (see Sections 2nd
3). A wood plank darn was constructed across the Pinehurst Narrows to retain tailings within
the floodplain of the SFCDR. Failure of dam and subsequent flooding resulted in a portion of
the tailings being spread downstream.
For the purposes of describing this remedial action, the boundaries of the Smelterville Flats
area (Flats) are the northern bank of the SFCDR floodplain, Pinehurst Narrows to the west,
the town of Smelterville on the south and the 1-90 West Kellogg interchange on the east
(Figure 2).
4.3.3.2 Review of ROD, ESD, & ROD Amendment Requirements
Remedial actions for the Flats area as prescribed in the 1992 ROD and the 1998 ESD are
listed below:
Table 4-5
Smelterville Fiats Remedial Actions
ROD and ESD Requirements
Remedial Action
Objective/Goal
Document
1. Rock/vegetation barriers on truck stop and RV park
Minimize direct contact
ROD 9.2.2
2. Temporary dust control during remediations;
re-vegetate as part of long-term solution
Minimize surface water erosion
and wind dispersion of
contaminants
ROD 9.2.2
3. Soil or rock barriers on exposed contaminated soils
and tailings that cannot be re-vegetated
Minimize direct contact
ROD 9.2.2
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Table 4-5
Smelterville Flats Remedial Actions
ROD and ESD Requirements
Remedial Action
Objective/Goal
Document
4. Remove tailings as necessary for natural wetland
and floodway construction
Control migration of contaminants
to surface and groundwater,
minimize the potential need for
future water treatment
ROD 9.2.2
5. Construct groundwater treatment wetland system
upstream of Pinehurst Narrows
Control migration of contaminants
to surface and groundwater
ROD 9.2.2
6. Construct collected water wetland treatment
system
Treatment of specific surface
waters collected at the Site,
reduction of contaminants to
SFCDR
ROD 9.2.2
7. Treatment Wetlands, if constructed will most
likely be located in an area different from
Smelterville Flats
Treatment of specific surface
waters collected at the Site,
reduction of contaminants to
SFCDR
ESD 4-98
8. Construct floodway for SFCDR
Minimize surface water erosion
and sedimentation
ROD 9.2.2
9. Runoff controls will be constructed south of 1-90
in areas expected to be developed and paved
Minimize infiltration and
percolation into underlying
contaminants
ESD 4-98
A. Final Design Solutions for the Flats
Ultimately, many of the potential design solutions for the Flats were significantly
modified. As part of the State Superfund Contract, an agreement was reached to
emphasize source removal actions as an initial response over treatment systems in
the Flats and Gulches areas (refer to Section 3.5). This resulted in two significant
changes to the design of the Flats project. First, near total removal of the tailings in
the Flats was determined to be the most cost-effective method to reduce the potential
need for groundwater and surface water treatment-based remedial actions.
Consequently, tailings were removed at quantities that greatly exceeded those
directed to be adequate by the ROD. EPA and the State of Idaho removed over 70
percent more tailings volume from the Flats than that originally proposed as
adequate to protect human health and the environment within the ROD (shown as
Remedial Element #4 in Table 4-5). Second, EPA and the State decided that
increased source removals would also occur in Government Gulch.
As a result of the large-scale source removals in both the Flats and Government
Gulch, EPA and the State decided to defer construction of the groundwater and
surface water wetland treatment systems that the ROD requires to be constructed in
the Flats in order to evaluate if the increased focus on source removal will reduce
and/or eliminate the need for further treatment.
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When EPA took over the Site in 1995, subsequent bench studies by the U.S. Bureau
of Mines showed that the technical approach for the constructed wetlands was not
viable on a year-round basis for the desired water quality discharge requirements
(CH2M HILL, 1996). Bench-scale laboratory studies were performed by the Bureau
of Mines specifically to test this treatment process on Bunker Hill mine water. The
bench scale program did not achieve treatment objectives (USBOM,1998).
If in the future, further treatment is determined necessary, the results of the
constructed wetlands treatment study will be re-evaluated, as well as other types of
treatment.
As a result of this 5-year review, EPA will evaluate the need for an Explanation of
Significant Differences or ROD Amendment to address the increased tailings
removal on the Flats and the decision to defer construction of the groundwater and
surface water wetland treatment systems.
4.3.3.3 Description of Remedial Actions Conducted at the Site
A. Rock/Vegetation Barriers on Truck Stop and RV Park
The truck stop and RV park are located north of the SFCDR and east of the Theater
Bridge (Figure 2). Pintlar capped both of these areas in the early 1990s. However, the
material used for the cap was too high in arsenic to be acceptable. In 1996 to 1997,
additional clean material was placed on the RV park (Chavez, 2000). Recapping of
the truck stop area has been partially accomplished with a 6-inch layer of topsoil
placed over the portion of the property owned by the truck stop. This area will
eventually be seeded and used as a picnic area (Chavez, 2000).
B. Temporary Dust Control during Remediations; Re-vegetate as Part of
Long-Term Solutions
During the tailings removal actions on the Smelterville Flats, dust suppression
techniques were used during construction to minimize the amount of dust
dispersion. Haul roads to the CIA were also watered to control dust. As part of the
long-term remediation, all areas surrounding the SFCDR upper bank and
throughout much of the reconstructed floodplain were hydroseeded. Riparian
plantings consisting of trees and shrubs are scheduled for installation during 2000 to
2001.
C. Soil or Rock Barriers on Exposed Contaminated Soils and Tailings That
Cannot Be ReVegetated
EPA and the State removed tailings from the SFCDR Floodplain in 1997 and 1998. A
6-inch to 8-inch layer of imported "clean" topsoil (less than 100 mg/kg lead) was
placed over areas where contamination remained and where material was too coarse
to support vegetation.
The remaining contaminated soils were capped with a clean soil barrier to prevent
direct contact with underlying contaminants by humans and animals.
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D. Remove Selected Jig Tailings as Necessary for Natural Wetland and
Floodway Construction
EPA and the State have removed nearly all of the tailings within the Flats area north
of 1-90 and transported these materials to the CIA for disposal.
Soil removal actions in the Flats were performed with the intent of maximizing
source control via contamination removal. To that end the decision was made to
remove as much mine waste tailings as possible to the CIA for containment. Several
test pit investigations and borings performed during the RI and remedial design
phases of the project found the depth of tailings to be highly variable. They extended
from one foot to 8 feet below the ground surface. The project team linked these
results to visual identification of tailings and native alluvium by a Removal
Verification Team (RVT). Representatives of the EPA, IDEQ, and the US ACE
formed the RVT. The RVT acted in conjunction with verification sampling to
determine how much contaminated material should be removed from any given area.
Lab analysis identified the levels of lead and zinc within verification samples. If
necessary, further excavation occurred beyond the level established by visual
inspection based on these sample analyses. The project team determined that removal
of tailings to a level cleaner than the sediments carried by the river was impractical
(Hudson, 2000, Zilka, 2000). Consequently, the RVT set 3,000 mg/kg lead and 3,000
mg/kg zinc as removal goals. These are the concentrations found in the sediments
typical of the SFCDR as documented in the RI (McCulley, Frick, and Gilman, 1992).
It should be noted that the 3,000 mg/kg removal goals for lead and zinc are not
requirements of the ROD and were used on a site-specific basis for the Smelterville
Flats removal actions only. In addition, as noted above, a clean soil barrier layer (less
than 100 mg/kg lead) was placed on top of exposed removal areas. The soil barriers
were re-vegetated to stabilize the soil and minimize erosion. Riparian plantings are
planned in late 2000.
E. Construct Floodway for SFCDR
The ROD further directed river work to improve groundwater and surface water
quality by protecting sediments and remaining contamination from transport during
flood events. The ROD also stressed erosion prevention. The ROD discusses how
improvement to aquatic habitat could occur as part of the remedial design solution.
Performance standards for the low-flow channels and floodplain were established in
CH2M HILL (1996) as:
Convey the estimated 2-year and 100-year recurrence-interval peak flows
without increasing water surface elevations upstream of the Theater Bridge
beyond those that would occur for this flow under existing conditions.
Maintain the current level of flood protection for 1-90 and the airport for the
100-year recurrence-interval peak flow.
Eliminate impact to current flood flows in the SFCDR downstream of the
project area.
Develop a "stable" low-flow channel and floodplain system, keeping the
lowflow channels along the northern part of the valley similar to existing
conditions.
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Ensure that the reach of the SFCDR affected by these remedial activities has
post-remedial action characteristics consistent with a functioning native
species fishery.
Control sediment during construction to avoid adverse impacts to SCFCDR
biota to the extent practicable.
Minimize erosion after construction is completed.
Specific remedial work consisted of:
Grading back the riverbanks.
• Armoring the lower bank with riprap.
Creating a flatter sloped upper bank protected with a combination of riprap,
growth media and live branch plantings.
Construction of spillways and sills in the river channel.
Construction of low flow channels and overflow channel in the floodplain.
Reseed native, organically enriched topsoils across much of the Flats.
Winter 2000 riparian plantings in floodplain area.
The river stabilization was constructed in 1997 through 1998.
The riverbanks and floodways were specifically designed to minimize the
recontamination potential from SFCDR sediments during high flow events. The
interim O&M plan that is being implemented at the Smelterville Flats specifically
focuses on preventing recontamination of the barrier caps placed on the Flats.
F. South of 1-90 Tailings Removals
Tailings were also removed south of 1-90 as part of the Smelterville Flats remedial
action. The tailings removal areas are designated as the West End and West County
removal areas (Figure 2}. The West End area is a narrow strip of land bounded on
the north by 1-90, on the west and south by the UPRR right-of-way, and on the east
by the City of Smelterville wastewater lagoons. The West County area is also
bounded on the north by 1-90, on the west by the Smelterville wastewater lagoons, on
the south by the UPRR and on the east by the right-of-way of "Silver Road".
Tailings were removed in these areas until alluvium was reached, generally between
depths ranging from 5 to 10 feet, and were hauled to the CIA for disposal. The areas
were regraded for drainage purposes and clean borrow soil from the Borrow Area
was placed to bring the excavations to a suitable grade for long-term drainage. The
remediated areas were revegetated protect the surface cap and to minimize erosion.
Further tailings removal actions to the east of these areas were not conducted by
EPA and the State as these properties were either already capped, were owned by
PRPs of the site, or were currently under high use by community industrial
businesses. In lieu of tailings removal actions in these areas, EPA and the State chose
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to conduct surface water drainage improvements to minimize infiltration into the
underlying tailings (as described below).
G. South of 1-90 Runoff Control and Capping
Improvements to runoff control and capping of tailings remaining in-place after the
West County and West End removal actions are planned for developable areas
immediately south of 1-90 near Smelterville in order to minimize percolation of
runoff into the underlying contaminants (EPA, 1998). Runoff control measures are
intended to reduce the potential for metals leaching into groundwater. The cap will
conform to ICP requirements and prevent direct contact with contaminants and
minimize the potential for windblown dispersion of dust. Remedial design for this
activity is currently ongoing with construction slated for the summer of 2000.
Runoff control will be achieved by regrading the area and constructing a vegetated
swale and storm-drain pipe parallel to 1-90. The conveyance will transport
stormwater from just south of 1-90 and west of the Smelterville interchange
approximately 6,500 feet west to a newly constructed sedimentation pond in the
West End removal area (Figure 2). The majority of the stormwater conveyance will
be in a swale, with the portion adjacent to the Smelterville wastewater treatment
ponds in a buried pipe. Tailings beneath the profile of the swale will be over-
excavated to a depth of 2 feet below the final grade of the swale and backfilled with
clean (less than 100 mg/kg lead) soil and growth media and then vegetated. The
properties through which the storm conveyance will run and from which tailings
were not removed will be capped with a minimum of 6-inches of rock to prevent
direct contact with tailings and reduce dust generation.
The project team is designing this remedial action to work in conjunction with future
anticipated development of these properties.
4.3.3.4 SAMP - Maintain the Integrity of the Remedy with Future Uses
To protect the integrity of the remedy implemented in the Flats, the State of Idaho is
preparing a Special Area Management Plan (SAMP). The plan is intended to establish
common understanding of the Flats remediation, interaction with future development, long-
term floodplain function, and establishment of a streamlined permitting process for future
activities. The decision to develop such a plan was adopted in the 1998 ESD (EPA, 1998).
The intent of the SAMP is to provide a comprehensive, long-term approach to resource and
floodplain management that considers all stakeholder interests within the Flats area. The
SAMP will provide a common vision for the Flats to improve permitting of local
development while recognizing the functional role of floodplain and other natural
resources. This will improve predictability for development interests and local governments
without sacrificing environmental function. The SAMP helps assure agencies that impacts
are identified, acknowledge, and accepted as part of an overall strategy for final Flats
configuration, stabilization, and function (Bourque, 1997).
The removal action performed in the Flats resulted in excavation of approximately 45 acres
of land previously outside the 100-year floodplain (north along the airport) to below the
100-year floodplain elevations. Although the positive results of reduced metals loading to
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the SFCDR, floodplain stabilization, and enhanced aquatic and wildlife habitat, are expected,
some long-term concerns remain. These include:
Ability of the floodplain to naturally stabilize within a reasonable time frame.
Continued metals contribution from remaining tailings.
Protection of the Shoshone County Airport.
Loss/impact of currently developable County property.
As part of the SAMP, an interagency group will oversee preparation of a master plan for the
Flats to address these concerns. The participating agencies and officials will include:
Shoshone County, the City of Smelterville, IDEQ, Idaho Department of Water Resources,
US ACE, U.S. Federal Emergency Management Agency, EPA, BLM, USFWS, Idaho Fish and
Game, and the Coeur dAlene Tribes. A primary goal of this group is a common
understanding of interim and final cleanup concepts, stabilization, and restoration within
the context of current and future floodplain work. In recognizing these aspects, this-group
will develop an interagency agreement, through the SAMP, that produces a strategy for
land use within the Flats area.
The SAMP team will identify several jointly beneficial actions and management options
such as:
Capping remaining tailings with impervious structures, buildings, and pavement to
prevent infiltration into tailings while providing for development.
Enhanced protection of the Shoshone County Airport with expanded development
along the northeast corner of the Flats.
Floodplain stabilization off-sets by developers to fund subsequent floodplain
activities.
Higher public awareness of the beneficial function of the restored floodplain
4.3.3.5 Operations and Maintenance (O&M)
Long-term O&M for the Flats is the responsibility of the State of Idaho. The State will take
over this aspect when the remedy is determined to be complete. Monitoring of the Flats will
occur during an interim 3-year period (CH2MHILL, December 1996). After this period, the
formal transfer of responsibility to the State from EPA will occur. Although willows will not
yet have been planted, the 3-year stabilization period is scheduled to begin October 15, 1999
(TerraGraphics, 2000).
The focus of the O&M interim period is to:
Create an O&M plan for the Flats and develop the State of Idaho's process for
implementing O&M activities.
• Implement O&M activities and monitor the achievement of interim and long-term
performance standards for the Flats.
Revise, as necessary, the performance standards and interim O&M manual and
procedures for the Flats to reflect the experience gained and lessons learned during
the interim period.
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Demonstrate the achievement of all final performance standards for the Flats.
The interim O&M manual was completed in May 2000 (TerraGraphics, 2000). The manual
includes scheduled and unscheduled O&M requirements, repair standards and authorization,
equipment and personnel requirements, refinements and modifications, and other
considerations such as regulations, unresolved decisions, and equipment and personnel
substitutions.
IDEQ and EPA jointly prepared the O&M Manual for the Flats. The agencies chose the Flats
area for the first O&M Manual because remedial activities in this area are very close to
completion. Lessons learned from its development will be applied to the completion of the
remaining O&M Manuals (TerraGraphics, 1999a)
Specific items that will need to be performed under Operations and Maintenance include
inspection and repair if required of:
Riverbanks: Check for bank erosion, bare ground, vegetative cover, riprap condition.
Sills: Check for structural condition, downstream scour, lateral erosion, head cutting,
deposition, and flow control.
Spillways: Check for debris, riprap condition, headcutting.
Floodplain: Check vegetative cover.
Floodplain Berm: Check for structural condition and vegetative cover.
Wetland Ponds: Check for vegetative cover and deposition.
Wetland and Upland Re-vegetation Areas: Check vegetative cover.
4.3.3.6 Assessment of Remedial Actions Conducted at the Site
A. Evaluate remedy performance
1. Rock/vegetation barriers at truck stop and RV Park.
The RV Park remediation has.been certified as complete (Chavez 2000). The
area used as a truck stop is still in need of re-capping.
2. Temporary dust-control during remediation; re-vegetate as part of
long-term solutions.
This remedial activity is in progress. The 'Emerald Pond' area just west of
Theatre Bridge (Figure 2) was one of the first completed areas of tailings
removal and reconstruction. This area shows a significant amount of natural
wetland vegetation that has occurred without planting. The response of Emerald
Pond to the reworking of the Flats appears very favorable. Grasses and forbs
were hydroseeded throughout the Flats area to begin establishment of
herbaceous cover. Additional herbaceous work is not expected to begin until
there is an opportunity to see how nature responds to the soils and hydrological
regime that has been created elsewhere on the Flats.
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3. Soil or rock barriers on exposed contaminated soils and tailings
that cannot be re-vegetated.
This remedial action is still in progress. Surface barriers, particularly in the East
of Theater Bridge area of the SFCDR, are placed in lieu of complete removals.
The choice of soil or rock barriers depends on future land use. High flows of the
SFCDR have not been experienced since installation and may cause changes
that will require repair or re-evaluation of the remedy. The highest flows
generally occur in late winter and early spring and should provide needed
information as to the performance of the remedy over the 3-year interim O&M
interval.
4. Remove selected jig tailings as necessary for natural wetland and floodway
construction.
As discussed in Section 4.3.3.2 A, over 70 percent more tailings were removed
from the Flats area than was identified in the ROD (1.2 million cubic yards
versus 700,000 cubic yards). The larger scale removal is expected to result in
less migration of contaminated sediment to surface water and groundwater in
the Flats area. Performance monitoring will continue to determine the effects of
this larger scale removal action in relation to water quality improvement at the
Site, as well as monitor the potential for recontamination of the floodplain. As
noted previously, if the large-scale removal actions do not improve water
quality to desired levels, water treatment or other remedial alternatives will be
evaluated.
5. Construct floodway for SFCDR.
Construction was performed as designed. The stabilization project is still in
progress, as the upper bank planting and riparian plantings have not yet been
installed. Evaluation of the floodway's success relative to its performance
standards should be made after the 3-year interim period to take into
consideration plant establishment and seasonal flow fluctuations.
6. South of 1-90 Tailings Removals.
The tailings removal project in the West End and West County areas is
protective in that, as much as practicable, tailings were removed down to natural
alluvial gravels. Water quality is expected to improve over time since these
tailings are removed and no longer in contact with infiltrated water or the
fluctuation of the groundwater table. The surface cap placed on top of the
removal grade provides for controlled surface water drainage and support
vegetation to minimize erosion.
7. South of 1-90 Runoff Control and Capping
This project will be constructed during the summer of 2000. The design criteria
established for this action (over-excavating tailings beneath the runoff control
channel (swale) by 2 feet and placement of a minimum 6-inch thick cap across
the property sites) are expected to provide an adequate level of protection from
direct contact with contaminants and a reduction of contaminant migration into
the underlying groundwater.
B. Discuss New Information
As stated in Section 4.3.3.2, the bench scale constructed wetlands treatment study
conducted by the Bureau of Mines in 1998 indicated that the constructed wetlands
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
treatment process as currently configured would not be optimal to treat metals-laden
water under site conditions and required discharge requirements.
The SAMP is intended to provide an approach to cooperatively manage the Flats and
to integrate new information into decision-making in the future.
C. Identify Deficiencies
As noted above in Section 4.3.3.6 A, the truck stop portion of the RV Park is still in
need of re-capping.
D. Recommend Improvements
It is recommended that the Flats area be included in future biological monitoring of
plant and wildlife that is planned to begin in 2000 under an inter-agency agreement
between EPA and the USFWS (Section 4.2).
4.3.4 Central Impoundment Area Closure
4.3.4.1 Introduction and Background
The CIA area was originally constructed in 1928 as the Bunker Hill Mine tailings
impoundment. The upstream method of impoundment construction was used to raise the
height of the exterior dikes as new tailings were placed. The entire structure was constructed
over river gravel and a 1 to 5-foot thick layer of jig tailings.
The CIA was operated in a manner similar to a dewatering pond in that it was intended to
accept slurries and saturated materials, allowing the liquid to drain through the dikes and
ultimately discharge to groundwater or surface waters. Tailings, gypsum, and some mine
waste were delivered to the CIA as slurry. Other materials were discharged as liquid or
dumped from trucks on the more stable areas.
As shown in Figure 4, the CIA is composed of three cells defined by area and material
placed. The West Cell contains primarily granulated slag from the Lead Smelter, the Middle
Cell contains gypsum by-product from the production of phosphoric acid and overlies
flotation tailings, and the East Cell contains primarily flotation tailings from the Bunker Hill
Concentrator. The Middle and East Cells are separated by a buried dike, which extends to the
surface. The surface area of the top of the CIA is about 260 acres.
Disposal of operational and process waste streams on the CIA was mostly discontinued
when the Bunker Hill mine was shut down in 1982. However, the Central Treatment Plant
(CTP) continues to the present to dispose sludge to one pond on the CIA. However, this
pond is estimated to have only a few years of remaining capacity and would be closed once
it could no longer accept sludge. As part of the Bunker Hill mine water RI/FS further
discussed in Section 4.3.8, other options for sludge disposal are currently being considered
including new lined sludge ponds on the, CIA as well as offsite sludge disposal.
Additionally, for many years, the top of the CIA provided mine water storage prior to
treatment at the CTP, either in the decant pond or flooding the entire East Cell (Figure 4).
The last time the CIA was flooded by mine water was in the winter of 1995 (CH2M HILL,
1996).
As discussed above, the tailings were often placed in the CIA as slurry. It has been
hypothesized that the water from these slurries, as well as water impounded on top of the
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
CIA in unlined ponds, has resulted in an isolated location of seepage from the CIA to the
north and into the SFCDR, referred to as the "CIA seeps". However, this hypothesis has not
been conclusively proved and other potential sources of seepage may be contributing to
contaminant loading to the SFCDR. Specifically, the area where the CIA has been
constructed is part of the old river channel of the SFCDR and as a result, the base of the CIA
lies on top of a gravel alluvial layer. It has also been hypothesized that seepage beneath the
CIA may come from tributary creek sources on the Site (e.g., Magnet and Deadwood
Creeks) that have a portion of their subsurface flow moving beneath the CIA into the
SFCDR. At times when the river stage of the SFCDR is high (during spring run-off, for
instance), the CIA seeps are not visible, but otherwise in low river water conditions, the seep
locations into the SFCDR can be visually observed.
4.3.4.2 Review of ROD, ESDs and ROD Amendment
Table 4-6 summarizes ROD and ESD requirements for the Central Impoundment Area
remedial action.
Table 4-6
Central Impoundment Area Remedial Actions
ROD and ESD Requirements
Remedial Action Objective/Goal
Document
1. Temporary dust control measures
Minimize releases from this source
ROD 9.2.3
2. Institutional controls
Prevent direct contact
ROD 9.2.3
3. Collection of upper zone groundwater in
CIA seep area, for wetland treatment
Maximize efficient interception of
contaminated groundwater from the "CIA
seeps"
ROD 9.2.3
ROD 9.2.10
4. Repository for consolidation of tailings,
gypsum, and other non-principal threat
materials removed as part of site removals.
Consolidation of Industrial Waste Landfills
to the CIA.
Consolidation of Arizona Mine Dump rock to
the CIA.
Limited quantities of mine waste from other
areas of the Coeurd'Alene Basin may be
disposed in the CIA.
Prevent direct contact and minimize
infiltration through contaminated media.
ROD 9.2.3
ESD 4-98
ESD 4-98
ESD 4-98
5. Close CIA without removing approximately
30,000 cubic yards of suspected principal
threat materials that were placed in the CIA
by the PRPs in 1982.
Increased protectiveness is provided by a
lower permeability cap (1X10 7 cm/sec),
that is specified in the ROD.
ESD 4-98
6. Close CIA with a cap having a hydraulic
conductivity of 1 X10"6 cm/sec or less, and re-
vegetate.
Minimize infiltration and control erosion.
ROD 9.2.3
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NORTH
EMBffNI
SMELTER MATERIAL
ACCUMULATION AREA
GYPSUM POND A-5
BURIED DIKH-—
{APPROX LOCATION)
MIDDLE DIKE
OLD PHOSPHATE
PLANT OUTFALL
EXISTING DECANTS
(APPROX LOCATION
FORMER POUSHING POND—
(RECYCLE CLEARWELL, DRY)
DECANT POND
EXISTING DECANT
STRUCTURE
OLD DECANT
STRUCTURES
{APPROX LOCATION^
GYPSUM
POND A-Sf"
ICPLANTS
CH2IWIHILL.
SCALE IM FEET
Figure 4
CIA Location Map
aUNKER HIU. NCN-POPULATEP AREAS
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
4.3.4.3 Description of Remedial Actions Conducted at the Site
A. Temporary Dust Control Measures
In 1995, Pintlar rocked the majority of the East and Middle Cells of the CIA for the
purposes of minimizing air-borne dust from the CIA. During the government-
implemented remedies, construction dust was also suppressed by watering the CIA
and applying chemical sprays to inhibit dust (MK, 1999). The geomembrane cover
placed on the CIA and the vegetating and rocking the exterior slopes are permanent
means to mitigate dust from the CIA.
B. Institutional Controls
As stated earlier (Section 4.1.2), one of the primary goals of the ICP is to prevent
direct contact between humans and the remaining contamination. Several aspects of
the CIA remedial action address this concern. A geomembrane cover system and
vegetated surface will prevent direct exposure on the top of the CIA and the side
slopes will either be rocked or revegetated to prevent direct contact. In addition, the
area is entirely fenced to prevent unauthorized access.
C. Collection of Upper Zone Groundwater In CIA Seep Area For Wetland
Treatment (Install System To Recover And Treat Contaminated Groundwater
Surfacing North Of The CIA Through CIA Seeps. Convey to Constructed
Wetland Treatment System.)
As part of remedial design, CH2M HILL conducted an evaluation of the feasibility of
collecting the CIA seepage in the upper groundwater zone (CH2M HILL, 1996b).
This evaluation indicated that it was not cost effective to collect and treat the CIA
seeps, primarily because a collection system would intercept a larger portion of
upstream groundwater than the actual CIA seeps. In addition, engineering analyses
indicated that once the CIA cap is completed and stormwater controls are in place,
that the ongoing consolidation of the tailings in the CIA and gravity drainage of the
water in the tailings would decrease over time such that 90 percent of the seepage in
the CIA tailings pile would have drained in 10 to 15 years without active collection
(CH2M HILL, 1996b). Based on these evaluations, EPA and the State decided to
defer construction of a seep collection system and instead will monitor the seeps
after placement of the CIA geomembrane cap to evaluate whether the seepage flow
is significantly reduced or eliminated over time.
Based on the above, EPA will evaluate the need for an Explanation of Significant
Differences or ROD Amendment to address the deferment of construction, of a seep
collection system.
D. Consolidate Jig Tailings from Smelterville Flats, Close CIA with 1x10-7 cm/sec
Cover, Re-Vegetate
Approximately 1.2 million cubic yards of material from the Smelterville Flats,
additional material from the mine waste dumps and gulches, and a layer of slag has
been placed on the CIA as of the end of November 1999. No additional materials will
be placed there. The surface has been brought to grade, the subgrade prepared, and
compaction was achieved. The outer perimeter dikes have been graded, rock cover
placed, toe sloping done, top of dike sloping completed, and a lot of slag placed to
date. The surface has been graded and the drainage channels installed. A polyvinyl
chloride (PVC) geomembrane cover was designed to meet the lxlO"7 cm/sec
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permeability criteria. The geomembrane cover installation is expected to be complete
by the end of the 2000 construction season.
E. Limited Quantities of Mine Waste from Other Areas of the Coeur d'Alene Basin
May Be Disposed Of In the CIA
During 1999, residential soil from EPA's yard removal program in the Coeur d'Alene
Basin was deposited in the CIA. In addition, some contaminated soil from the State
of Idaho Trustee projects was also disposed in the CIA.
4.3.4.4 Operations and Maintenance
An O&M plan has not yet been developed for the CIA Closure. General O&M requirements
for the completed CIA cover system are expected to include (CH2M HILL, 1997):
Periodic inspection and occasional maintenance will be required for the general
cover areas, drainage system and sludge ponds. This includes inspection and
maintenance of settlement areas and maintenance of the cover system such as
replacing soil, grass cover, or rock lost to erosion during severe storm events. Minor
regrading would be required in areas where settlement causes water to pond over
the cover.
The drainage system will require periodic inspection and cleanout of catch basins
and other structures.
Additional O&M requirements will be developed upon completion of the CIA Closure.
4.3.4.5 Assessment of Remedial Actions
A. Evaluate Remedy Performance
The CIA remedial action has been ongoing since 1995 when site removal materials
began to be consolidated in the closure area. The capping of the CIA is planned to
begin in 1999 and be completed in 2000. A complete assessment of the CIA remedial
action can therefore not be conducted until the full remedy is complete. Performance
observations from those remedial components that are complete are summarized
below.
1. Temporary Dust Control Measures
Dust suppression techniques are being used during construction. Once the cover
is in place contaminants from the CIA will be prevented from migrating as dust.
2. Institutional Controls
Fencing that is currently in place and enforced restrictions on access are
preventing direct contact between humans and contaminants on the CIA. When
the remedy is complete, the cover that will be placed will prevent direct contact
as well as dust generation and reduce infiltration of water and metals migration.
3. Collection of Upper Zone Groundwater in CIA Seep Area for Wetland
Treatment
As noted above, the collection and treatment of the CIA seeps is being deferred
until the effectiveness of the CIA Closure cap to minimize infiltration into the
underlying tailings has been evaluated. As noted in Section 4.3.4.3, 10 to 15 years
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has been estimated for the CIA to drain on its own after capping. Based on this
analysis, the next 5-year review will provide a mid-way point to evaluate whether
the expected natural gravity drainage of the CIA is on track. Also, as noted in the
Smelterville Flats section, construction of the treatment wetlands is being deferred
in order to evaluate if the increased focus on source removals will reduce and/or
eliminate the need for passive wetland or other type of treatment.
4. Repository for Consolidation of Non-PTM Materials from Site Removals
The material consolidation portion of the CIA remedial action is essentially
complete. An estimated 2 million cubic yards of tailings and mine waste material
has been consolidated in the CIA Closure since 1995. This large quantity of
material came from several on-site sources, and represents a significant increase
in protectiveness than if these site materials were left in place. Once the CIA
cover is in place and gravity drainage of water within the tailings is complete, the
underlying materials will be prevented from further leaching into surface water
and groundwater. Long-term monitoring of surface and groundwater in the
vicinity of the removal areas, as discussed in the site-wide monitoring program
(Section 4.2), should indicate the success of the waste consolidation activity at
minimizing metals releases from this source.
5. CIA Closure
This remedial activity is in progress. The final capping should be completed by
the end of the 2000 construction season. Collection and treatment of the CIA
seeps was identified as a component of the CIA remedial action, but has not yet
been implemented. First, the CIA remedial action will be evaluated to determine
whether the closure has successfully reduced the contaminant loading from the
CIA seeps to the SFCDR. This evaluation process will be based in part on the
results of long-term groundwater monitoring, as well as monitoring of surface
water and perched water within the CIA. Additionally, this evaluation will
consider the contribution of metals contamination from jig tailings located
underneath the CIA and throughout the valley floor.
In addition, the April 1998 ESD requires that the CIA be closed with a cap having
a permeability of at least lxlO"7 cm/sec (versus lxlO"6 cm/sec as required by the
ROD). This increased level of protectiveness was judged to be warranted by EPA
to further decrease potential infiltration through the closure cap in light of a
small amount (219,000 cyds) of PTMs known to exist in the CIA and also in light
of deferring the CIA seep collection.
B. New Information
The study of the collected water wetlands treatment system reported by the Bureau
of Mines in 1998 concluded that the current state of technology of this process would
not be effective under year-round site conditions for treatment of the metals. inA
treatment component for the site flows, including the CIA seeps, was therefore
deferred by EPA and the State in favor of more extensive removals of source
contaminants at the Site.
C. Identify Deficiencies
None were found.
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
D. Recommend Improvements
None at this time.
4.3.5 Page Pond Remedial Action - PRP-impiemented Remedial
Action
4.3.5.1 Introduction and Background
This remedial action is being conducted by the PRP group of Hecla, Sunshine Mining, and
ASARCO with oversight by the State of Idaho and EPA.
The Page Pond Area is located near the west end of the Bunker Hill site, and is bounded on
the east by the community of Smelterville, on the south and west by Highway 10, and on the
north by the Union Pacific Railroad Rights-of-Way (Figure 5). The Site comprises an area of
approximately 170 acres, including approximately 70 acres of tailings repository and
100 acres of wetlands and riparian habitat.
The Page Pond repository was used during the period between 1926 and 1968 as a deposition
area for flotation tailings generated at the Page Mill in nearby Humboldt Gulch.
Approximately 30 acres in the central portion of the inactive 70-acre tailings repository now
serves as the site of the Page Pond Wastewater Treatment Plant (PPWWTP) which was
constructed in 1974. The PPWWTP includes four aeration lagoons and a stabilization pond
located atop the tailings impoundment. Treated effluent from the PPWWTP currently is
conveyed to an outfall along the SFCDR approximately a half-mile upstream from the
confluence of the river with Pine Creek.
The Page Pond repository is essentially surrounded by water that isolates it from public access
except via the access road for the PPWWTP. Two natural wetlands, the East and West
Swamps, are located to the east and west, respectively, of the tailings repository. The wetlands
are connected along the north boundary of the repository by the North Channel, which
conveys water from the East Swamp to the West Swamp. A smaller channel (the South
Channel) is located along the southwest boundary of the repository and conveys localized
runoff from the southeast corner of the repository eastward into the East Swamp. The water
levels and surface areas of the swamps fluctuate seasonally with high water levels during
periods of heavy rainfall and snowmelt in the spring and early summer and low water levels in
the late summer and fall dry season.
In addition to the tailings in the repository, exposed tailings were present in the west end of
the West Swamp in an area known as the West Beach, in localized areas in the North Channel,
and in small quantities in other locations within the Page Pond area. Investigations of the East
Swamp did not identify any significant quantities of tailings.
4.3.5.2 Review of ROD, ESDs and ROD Amendment
The 1992 ROD identified the tailings in the Page Pond area as a source of localized
contamination of surface water and groundwater and of windblown dust. The east and west
bench areas adjacent to the PPWWTP is also serving as repositories for soils removed from
residential properties within the Bunker Hill site. Remedial actions specified in the ROD are
summarized below in Table 4-7.
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auNKER HILL NON-POPULATED AREAS
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 4-7
Page Pond Remedial Action
Remedial Actions
Remedial Action
Objectives/Goals
Success Criteria
Document
Source
Temporary dust control
Minimize exposure from
fugitive dust
Meet ambient air criteria
ROD 9.2.4
Institutional controls
Prevent direct exposure to
tailings and contaminated
soil
Reduce the potential for
accidental exposure
ROD 9.2.4
Maintenance of existing fencing
Prevent direct exposure to
tailings and contaminated
soil
Reduce the potential for
unauthorized access
ROD 9.2.4
Divert and modify the channels of
Humbolt and Grouse Creeks; consider
the effect of modifications on habitat
Isolate the creeks from
contact with tailings;
minimize habitat
destruction
Reduce releases from
tailings into surface
water; maintain habitats
ROD 9.2.4
Removal of exposed tailings from the
West Page Swamp area and
placement of this material on the Page
Pond benches
Minimize exposure from
fugitive dust; minimize
releases to surface water
and groundwater
Meet ambient air criteria;
reduce releases from
tailings to surface water
and groundwater
ROD 9.2.4
Regrading, capping, and re-vegetation
of the Page Pond tailings
impoundment and dikes after
emplacement of West Page Swamp
tailings
Minimize exposure from
fugitive dust; minimize
releases to groundwater
Meet ambient air criteria;
reduce releases from
tailings to groundwater
ROD 9.2.4
Evaluation of wetlands associated with
the Page Pond areas for water quality,
habitat considerations, and
bio-monitoring
Minimize habitat
destruction
Maintain habitats
ROD 9.2.4
Enhancement of existing wetlands in
West Page Swamp using hydraulic
controls
Improve wetland
vegetation and habitats
Enhance vegetation and
habitats
ROD 9.2.4
4.3.5.3 Description of Remedial Actions Conducted at the Site
The remedial action at Page Pond is ongoing and is planned by the PRPs to extend over
several years. The primary remedial action is planned to be implemented in four actions:
1. Removal of tailings from West Beach.
2. Removal of remaining localized accumulations of tailings and placement of clean soil
barriers.
3. Modifications to the South Channel to increase flow capacity and efficiency from
Humbolt Creek and to protect the toe of the south embankment; modifications to the
North Channel to accommodate diversion of wastewater from the PPWWTP into the
North Swamp; construction of the East Swamp and West Swamp outlet control
structures, discharge channel, and culvert to the SFCDR.
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4. Construction of internal beans within the West Swamp.
Of these four actions, only the removal of tailings from West Beach has been completed. The
remaining actions are at the design stage.
The design for removal of tailings in the West Beach area of the West Swamp called for
removal of tailings that were at an elevation higher than 2,187 feet (AMSL) to the extent
technically practicable. The reference elevation was established 2 feet below the free-water
surface that will be maintained in the West Swamp after construction of an outlet control
structure. The removed tailings were to be deposited onto the west bench adjacent to the
PPWWTP (the Page Pond repository).
Removal of approximately 40,000 cubic yards of West Beach tailings occurred in the winter
of 1997-1998. The tailings were placed into the West Bench area of the Page Pond repository.
About 50 percent of the tailings placed on the West Bench have been covered by soils from
the Milo Creek flood control project. The tailings will eventually be completely covered by
residential soils derived from the residential yard cleanup program of the Bunker Hill site.
When the repository reaches final grade, the residential soils will be vegetated to provide a
permanent cover for the tailings.
The current plan for Page Pond addresses other smaller accumulations of tailings that are
present in portions of the North Channel and in isolated areas of the West Swamp. Some of
these tailings will be completely removed in the same manner as the West Beach tailings. If it
is not practicable to remove tailings remaining in the West Swamp to the reference
elevation (2,187 ft. AMSL), then the remaining tailings will be left in place and covered with
a minimum of 12 inches of clean soil. Some tailings will be left in place above the reference
elevation without placement of a soil cover if the tailings are located in areas with well-
established wetland vegetation and if the vegetation would be destroyed by removal activities.
The Remedial Action Plan for Page Pond includes improvements to the North and South
Channels. Exposed tailings in the North Channel will be removed except where tailings will
be below the reference elevation, where removal is not practicable or where tailings will be
covered with embankment regrading materials. If exposed tailings remain above the
reference elevation they will be covered with a barrier layer of clean soil. The North Channel
will be trimmed to accommodate the design 100-year, 24-hour storm flow discharging from
the East Swamp. A vegetative cover will be provided in the North Channel to provide
erosion protection. A gated-concrete structure will be constructed in the North Channel to
allow for diversion of wastewater from the PPWWTP into the North Channel. To control
erosion, a grouted-riprap energy dissipation blanket will be placed over a non-woven
geotextile on a swale-shaped subgrade at the pipe outfall from the wastewater diversion
structure.
The west portion of the South Channel conveys discharge from Humbolt Gulch and runoff
from an adjacent road and repository embankments to the West Swamp. The east portion of
the South Channel conveys localized runoff from an adjacent roadway and repository
embankments into the East Swamp. Since the east portion of the South Channel conveys only
localized runoff, only minor construction such as channel trimming and grading are
planned. The west portion of the South Channel will be trimmed to convey the design
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
100-year, 24-hour storm flow from Humbolt Creek. Riprap erosion protection will be placed
along the toe of the repository embankment slope approximately 600 feet downstream from
the confluence of Humbolt Creek with the South Channel.
Outlet control structures are planned for construction in the East and West Swamps. The
outlet control structure for the East Swamp will be a weir across the eastern end of the
North Channel. The weir will allow discharge of water down to elevation 2,203.5 feet and
raise the discharge elevation by approximately 2 feet above the existing channel. The East
Swamp will remain saturated for longer periods of time but could shrink in area or become
dry during periods of extended dry weather. An outlet control weir will be located at the
western edge of the West Swamp that will maintain a water level two feet above exposed
tailings that remain in the West Beach. Since flows into the West Swamp will be
supplemented by discharge from the PPWWTP, the West Swamp should remain saturated
throughout the year. The outlet control weirs in each swamp will be constructed of
compacted earth fill on firm native soil and will include a reinforced concrete sill and
seepage barrier across the crest with an armored spillway on the crest and the downstream
face. To control seepage through and beneath the West Swamp weir, a geosynthetic clay
liner (GCL) will be used on the upstream face of the weir structure with an extension two
feet below the invert. The West Swamp weir will also be provided with a flume to allow for
measurement of flow rates and loading rates to the SFCDR.
The existing outflow from the West Swamp into Pine Creek will be plugged and a new
discharge channel and culvert will be constructed to allow direct discharge into SFCDR. The
channel from the new West Swamp weir will have a bottom width of 5 feet with 2:1
sideslopes, a minimum depth of 4.5 feet, a gradient of 0.005 ft. /ft., and a length of
approximately 420 feet. The new channel will be well vegetated to resist erosion. A new
72-inch culvert will be installed under the railroad embankment. The new culvert will be
provided with headwalls and riprap blankets to protect the railroad embankment, improve
flow into the culvert, and protect the channel from scour.
The existing plan calls for the construction of two internal berms in the eastern portion of
the West Swamp to promote a water flow. The final number and design of the internal
berms will be based on assessment of field conditions prior to construction. The internal
berms will consist of clean granular fill placed over soft marsh sediments. Approximately 6
inches of growth medium will be placed on the berms and the berms will be planted with
wetland/ riparian vegetation.
Access to the Page Pond area will be restricted to authorized personnel. Most of the area
will be surrounded by water that will restrict public access. The existing fencing and gates at
the point of entry to the Site will be maintained and upgraded as necessary. Public access
might be possible via the North Channel during dry periods. If this access route is found to
be significant, new fencing with warning signs will be installed to restrict access. The need
for and extent of new fencing will be determined in the field in consultation with EPA and
State oversight representatives.
Interim measures will be taken at the Site while the cleanup action is implemented. These
measures will include dewatering, stormwater management and sediment control, dust
control, decontamination, and traffic control. Dewatering of the swamps will be allowed to
occur naturally during the dry season to allow for minimum disturbance of wetland areas
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during construction. Dewatering might also include routing of drainage around areas during
construction. Stormwater management and sediment control will include placement of
temporary culverts to redirect flows and installation of silt fencing, straw bales or other
sediment control facilities downstream of work areas. Upon completion of work natural flow
paths will be restored and materials associated with sediment control will be disposed into the
Page Pond repository.
Dust control will be accomplished using water trucks with hoses or spray bars. Heavy
equipment, trucks, tools, and personnel will be decontaminated prior to leaving the Site in
accordance with the governing Health and Safety Plan. Most traffic will be controlled onsite,
however if it becomes necessary to move equipment along public roads the work will be done
in accordance with Idaho Transportation Department rules and regulations.
The Bunker Hill Populated Areas Operable Unit Five Year Review Report discusses and
evaluates potential recontamination issues associated with the PRPs residential soil, disposal
activities to the Page Repository. That document states that ICP soil samples obtained from
the adjacent road and near the Page Pond area's gate were above cleanup levels of lead (up to
5,937 mg/kg) indicating that the PRPs current vehicle decontamination procedures may not be
adequate. That document also recommended that additional decontamination and drainage
control procedures be implemented at the Page Pond area to mitigate future vehicle tracking
of contaminants.
4.3.5.4 Operations and Maintenance
Since construction of the majority of the Page Pond remedial action has not been completed, it
is not possible to describe the final O&M plan. However, there are some proposed interim and
post-closure O&M requirements that can be summarized. Objectives for interim O&M are to:
Preserve the integrity and effectiveness of completed components of the remedy.
Facilitate subsequent remedial actions.
Limit erosion and transport of potentially contaminated materials from the component
areas of the Site.
Prepare the Site areas for winter shutdown periods between construction seasons.
Interim O&M activities will include installation and maintenance of interim stormwater
management and sediment control facilities (ditches, silt fences, sediment traps, flumes,
splash pads, etc.) and dust control.
Post-closure O&M activities will focus primarily on ensuring the integrity of the closure
surfaces, drainage facilities, and site security provisions and on addressing monitoring of the
performance and effectiveness of the remedy. Closure surfaces and site security
provisions will be regularly inspected and repaired as necessary. Drainage facilities will be
inspected to identify the onset of erosion, displacement of riprap, loss of vegetation,
localized slope instability, or debris deposition and will be maintained and repaired as
necessary.
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Environmental monitoring will include sampling and testing of upstream and downstream
surface water and effluent from the PPWWTP, sampling and testing of upgradient and
downgradient groundwater, sampling and testing of soils and sediments in the West
Swamp along surveyed transects, and monitoring of the establishment of wetland/riparian
vegetation on the Site. Environmental monitoring will be reviewed every 5 years to evaluate
the need for a continued long-term environmental monitoring program.
4.3.5.5 Assessment of Remedial Actions
A. Evaluate Remedy Performance
The only remedial action that has been completed at the Page Pond site is removal and
relocation of tailings from the West Beach area of the West Swamp. The cleanup
action was completed in accordance with the ROD. The only remaining work to be
done on this cleanup action is the covering of the tailings with residential soil. This
work will be completed as additional residential soils are generated from the ICP.
Interim dust control measures will prevent air releases from uncovered West Beach
tailings and interim access controls will prevent exposure.
The remaining remedial actions for Page Pond are expected to meet ROD
requirements for minimizing releases to air, sediment, and soil and enhancing wetland
vegetation. The increased water level in the East Swamp will prolong the seasonal
high water level and enhance wetland vegetation. The increased water level in the
West Swamp, in combination with flow diversion from the PPWWTP into the West
Swamp, are expected to enhance wetland vegetation and prevent tailings remaining in
the swamp from drying out and becoming fugitive dust. The establishment of wetland
and riparian vegetation in combination with other erosion controls will minimize
releases of tailings and their potential contamination of sediment. Placement of a
vegetated residential soil cap over tailings deposited on the East and West Benches
will prevent releases to soils and minimize potential exposure to waterfowl feeding in
the area and to humans.
According to design analyses, releases of metals from tailings into surface water and
groundwater will be minimized by placement of a vegetated residential soil cap over
tailings on the east and west benches, maintenance of an elevated water level in the
West Swamp, and the diversion of wastewater from the PPWWTP into the West
Swamp. The vegetated residential soil cap on the benches is designed to increase
evapotranspiration and reduce leachate generation and subsequent groundwater
contamination from infiltration through the tailings. The increased water level and
wastewater diversion into the West Swamp are designed to maintain a near neutral pH
and create metal sulfides that will decrease the mobility of metals in tailings or
sediments remaining in the West Swamp. Since these RAs have not been constructed,
an evaluation of the effectiveness of these remedies cannot be completed at this time.
Post-construction surface water and groundwater monitoring will be necessary to
evaluate the effectiveness of these RAs on reducing releases to surface water and
groundwater.
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B. Discuss New Information
In 1996, EPA requested technical assistance through an interagency agreement from
the USFWS to characterize wildlife and vegetation in the Page Ponds area. This
information was to document baseline biological conditions prior to remedial
actions. A final report, prepared by USFWS in 1999, includes a waterfowl and
breeding bird survey, identifies seasonal waterfowl use of the Page Ponds area
including the treatment ponds and swamps, discusses waterfowl blood sample
results, and characterizes the wetland and riparian vegetation in the swamps (Audet et
al., 1999). The report concludes that: waterfowl numbers and diversity are most likely
impacted by human activity adjacent to the treatment ponds and swamps; waterfowl
captured in the East Swamp had elevated blood lead concentrations; and that possible
sources of lead include tailings present in the ponds and swamps, possible airborne
deposition, and storm water run-off entering the treatment ponds. These results will be
used in the development of the biological monitoring program for the entire site,
discussed in section 4.2 of this document, which is currently being planned.
C. Deficiencies Identified
A recent draft memorandum (CH2M HILL, 1999) has recommended improvements to
the Page Pond baseline and routine groundwater and surface water monitoring
programs. In particular, the draft memorandum indicates that four of seven existing
monitoring wells plus two new wells should be included in the groundwater
monitoring program (see Figure 5). The memorandum proposes the establishment of
four new surface water monitoring stations. Proposed parameters for groundwater
monitoring wells are lead, zinc, cadmium, arsenic, nitrate, phosphate, iron, manganese,
ammonia, total organic carbon, pH, specific conductance, temperature, and static water
level. Proposed surface water chemical monitoring parameters are the same as for
groundwater except for the addition of total Kjeldahl nitrogen, dissolved organic
carbon, total suspended solids, and dissolved oxygen. Flow rates at each surface-water
monitoring station are also proposed in the memorandum. Additional details regarding
proposed monitoring stations, frequencies, and parameters are provided in the draft
memorandum.
The information in the draft memorandum suggests that there are possible deficiencies
in the existing Page Pond monitoring program. The memorandum will need to be
reviewed, revised, and finalized before the possible deficiencies can be verified and
remedied.
D. Recommended Improvements
The Bunker Hill Populated Areas Operable Unit First Five Year Review Report
discusses and evaluates the potential for inadequate decontamination procedures at the
Page Ponds area that has resulted in vehicle tracking of contaminants to the Populated
Areas of the Site. For further information and recommendations on this topic, please
refer to Populated Areas First Five Year Review Report.
The memorandum regarding the Page Pond monitoring program (CH2M HILL, 1999)
makes the following recommendations for further action and evaluation:
Clarify regulatory considerations regarding beneficial wetland use, and
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discharge of sewage effluent to a water of the state.
Develop a work plan that describes monitoring well installation, installation
of surface water flow measurement devices, Quality Assurance and Quality
Control (QA/QC) requirements and data quality objectives for water quality
sampling and analysis, sampling protocols, database management
responsibilities, and routine reporting requirements.
Develop objective assessment statistical methods of analysis for determining
the overall effectiveness of the wet closure remediation.
Install additional groundwater monitoring wells, flow gauging devices, and
staff gauges to complete the overall monitoring network; survey, all new
wells and staff gauges to establish horizontal and vertical control.
Identify coordination opportunities with the administrators of other water
quality monitoring programs to minimize collection of potentially redundant
data.
As mentioned above, the memorandum will need to be reviewed, revised, and
finalized before these recommendations can be approved and implemented.
Other than possible changes to the monitoring program, there are no current
improvements that have been identified for the Page Pond remedial action. Longterm
O&M of the remedial action should minimize metals releases to air, soil, and
sediment. Future improvements might be necessary if post-construction
groundwater and surface water monitoring determine that significant metals
releases are continuing from the West Swamp or from the East and West Benches. If
metals releases continue from the West Swamp, additional chemical adjustment of
water within the swamp, or excavation and capping of additional tailings and
sediments might be necessary. If continued leaching of metals from the benches is
identified as a source of significant metals releases, installation of an impervious cap
over the benches might be necessary to further reduce infiltration into the tailings.
4.3.6 Industrial Complex Remedial Action
4.3.6.1 Introduction and Background
The 1992 ROD defines the Industrial Complex as comprised of three main areas: the Lead
Smelter, the Zinc Plant and the Mine Operations Area. This section focuses on the Lead
Smelter, Zinc Plant, Phosphoric Acid Plant and the various areas used to store mine process
materials (ores, concentrates, processed or partially processed material) associated with
these facilities. The Mine Operations Area is discussed separately in Section 4.3.7.
The Industrial Complex typically contained the most highly contaminated areas of the Site
with metal concentrations of mine processing material accumulations and soils well into the
percentage range in many instances. Process material accumulation sites were present
within and outside the various facilities. Risk assessments conducted during the Remedial
Investigation (RI) phase resulted in a sub-set of site process materials that were designated
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at Principal Threat Materials (PTMs) based on their higher level of contamination. PTM
action levels are:
• Antimony -127,000 mg/kg
• Arsenic-15,000 mg/kg
Cadmium - 71,000 mg/kg
Lead - 84,600 mg/kg
• Mercury - 33,000 mg/kg
Figure 6 shows the locations of the Lead Smelter, Zinc Plant, Phosphoric Acid Plant, and the
Smelter Closure area. The Smelter Closure area is where the demolition debris from the Lead
Smelter, Zinc Plant and Phosphoric Acid Plant and contaminated soil from various soil
removal actions across the Site were disposed.
4.3.6 2 Review of ROD, ESDs, and ROD Amendment
Table 4-8 summarizes ROD, ESD and ROD Amendment requirements for the Industrial
Complex remedial action.
Table 4-8
Industrial Complex Remedial Actions
ROD and ESD Requirements
Remedial Action
Objective/Goal
Document
1. Temporary dust control on material
accumulation sites
Control migration of windblown
dust
ROD 9.2.1
2. Remove PCB transformers and PCB
contaminated soils
Minimize direct contact risk
ROD 9.2.1
3. Repair or remove asbestos materials
Minimize direct contact risk
ROD 9.2.1
4. Institutional controls
Minimize direct contact risk
ROD 9.2.5
5a. Demolish Lead Smelter, Zinc Plant and
Phosphoric Acid Plant structures in-place
and cap to reduce infiltration.
5b. Place contaminated materials and debris
from the Zinc and Phosphoric Acid Plants in
the Lead Smelter Closure and eliminate the
closure planned for the Zinc Plant Area.
5c. Maintain the Zinc Plant Concentrate
Handling Building and Warehouse Building
so that these structures can be turned over
to the county for use as maintenance
facilities.
Minimize direct contact risk
Reduce O&M costs by
eliminating Zinc Plant closure.
Decontaminate structures to
minimize direct contact risk
ROD 9.2.5
ESD 12-95
ESD 4-98
6. Demolish the Phosphoric Acid Plant
warehouse
Minimize direct contact risk and
imminent safety hazard
ESD 4-98
7. Relocate Boneyard materials under Smelter
Cap
Minimize direct contact risk
ROD 9.2.5
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Table 4-8
Industrial Complex Remedial Actions
ROD and ESD Requirements
Remedial Action
Objective/Goal
Document
8. Consolidate under the Smelter Cap:
- slag from west cell of CIA
- material accumulations including former
waste disposal or holding pond
sediments within Smelter Complex
- contaminated soil, tailings, and mine
waste from removal actions conducted
within the Site boundaries
Minimize direct contact risk
ROD 9.2.5
9. Close the Smelter Closure area with a cap
having a hydraulic conductivity of 1 x 10"7
cm/sec or less and re-vegetate to minimize
erosion
Minimize direct contact and
infiltration and control erosion
ROD 9.2.5
10. Reprocess principal threat materials (PTM)
and other recyclable materials to minimize
the volume of materials under the closure
cap
Material reuse
ROD 9.2.5
11. Dispose PTMs under the Lead Smelter Cap
in a fully lined monocell (this amends ROD
9.2.5 which required chemical stabilization of
PTMs
Minimize direct contact risk and
reduce potential for migration to
groundwater
ROD Amdt 9-96
12. Demolish four (4) stacks in the Lead Smelter
and Zinc Plant
Minimize direct contact risk
ESD 4-98
4.3.6.3 Description of Industrial Complex Remedial Action
The primary objective of the Industrial Complex remedial action was to consolidate
contaminated soil and material accumulations from site removal actions and debris resulting
from demolition of the Industrial Complex structures into an engineered closure with a low
permeability cap. This section describes the various components of this remedial action.
A. Demolition of Industrial Complex Structures
Industrial Complex structures were demolished in two phases:
Demolition of Fire-Risk Structures (1995): Wood structures, within the Lead
Smelter and Zinc Plant, were demolished in the first phase of demolition in 1995.
A total of 87 structures (about one-fourth of the structural area) were demolished
(OHM, 1995). Prior to demolition, PCB-containing equipment was removed and
disposed in accordance with applicable regulations, asbestos was removed,
bagged and consolidated within a specific area of the Smelter Closure, and select
equipment was salvaged for reuse or recycling. Lead Smelter structures were
demolished in-place; Zinc Plant structures were demolished and than hauled to
the Smelter Closure for burial. Slag was used as in-fill material with the wooden
demolition debris to minimize void spaces and the potential for future
settlement.
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• Demolition of Lead Smelter, Zinc Plant, and Phosphoric Acid Plant (1995 -
1997): The remaining structures of the Lead Smelter, Phosphoric Acid and Zinc
Plants were demolished between 1995 and 1997 (Morrison Knudsen, 1999).
Similar to the procedures used for the wooden fire-risk structures, all PCB-
containing equipment or other hazardous materials werOe removed prior to
demolition. Asbestos abatement procedures were also similar with removed
asbestos continuing to be disposed in the southwest corner of the Smelter
Closure. Since the structures demolished in this phase were primarily steel and
concrete, the resulting debris often needed to be reduced in size in order to be
transported to the Smelter Closure as well as to minimize void spaces in the
closure area. Slag, and eventually contaminated soil from various site removals,
was used as in-fill for the debris.
The Smelter and Zinc Plant stacks were dynamited on May 26, 1996 (Morrison
Knudsen, 1999). The ROD initially did not require demolition of the two tallest
stacks, but rather that, at a minimum, they be decontaminated. As'noted in Table
4-8, the 1996 ROD Amendment revised the ROD to include demolition of these
structures. The Lead Smelter stacks were felled into the closure area and buried
with the rest of the demolition debris. The Zinc Plant stack was felled to the
northeast behind a small ridge and buried in-place.
B. Consolidation of Debris and Other Contaminated Materials in Smelter
Closure
The general intent of the ROD with respect to consolidation of contaminated materials
was to place the most contaminated materials within the Smelter Closure (and Zinc
Plant closure prior to its elimination in deference to a single debris closure area). For
this reason, the ROD requirements for hydraulic conductivity of the Smelter Closure
cap were one order of magnitude more protective (10-7 cm/sec versus 10-6 cm/sec)
than the ROD requirements of the CIA Closure cap. (However, as noted in Section
4.3.4, CIA Closure, the inclusion of a geomembrane cover for the CIA increased the
protectiveness of this closure to a level equivalent with the Smelter Closure).
However, the philosophy of placing the most highly contaminated materials in the
Smelter Closure continued, due in part to its greater distance from the SFCDR. Figure
6 shows the outline of the closure area. This area was designed to accommodate up to
420,000 cubic yards of material (CH2M HILL, April 1996, July 1996).
A brief description of the materials consolidated in the Smelter Closure follows:
Demolition Debris: As noted above, debris from the Lead Smelter,
Phosphoric Acid and Zinc Plants was consolidated in the Smelter Closure
area. The debris was sized and placed to minimize void spaces. Slag and
contaminated soil from removal actions was used to in-fill voids. The debris
and slag/soil layers were typically compacted by the traffic of track dozers and
haul equipment. The debris and soil were placed to the lines and grades of the
final closure plan (CH2M HILL, April 1997).
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Principal Threat Materials: PTM Mono-Cell: The 1996 ROD Amendment
revised the 1992 ROD such that all PTMs except mercury were to be
contained rather than stabilized. The ROD was amended because disposal of
the PTMs in a mono-cell was judged to be equally protective as stabilization and
up to 90 percent less costly. The requirement for stabilization of mercury
contaminated material was not revised. The containment system required by the
ROD Amendment is a fully-lined and sealed geomembrane mono-cell
constructed within the boundary of the larger Smelter Closure (CH2M HILL,
May 1996). Figure 6 shows the location of the PTM cell. Figures 7 and 8
provide more detailed plan and sectional views of the PTM cell. The PTM cell
was designed and constructed in 1996 through 1997. The PTM cell was
designed to have a maximum capacity of about 125,000 cubic yards of
material. The geomembrane cover of the PTM cell could be adjusted as
necessary to account for the wide volume range of expected PTMs. Stabilized
mercury contaminated materials were also deposited in the PTM cell. The
PTM volume placed in the cell was not surveyed, however, based on general
elevations of the top geomembrane cover, it is estimated that about 80,000 to
100,000 cubic yards of PTMs are contained in the PTM cell.
Boneyard Material: Figure 2 shows the general location of the Boneyard area.
This area was used by the operators of the Smelter to dispose of process material
accumulations and unused metal and wood debris from the facilities and
processing equipment. Sampling conducted during the Remedial Design phase
indicated that the majority of the contaminated Boneyard material was,located
within the upper 5 feet and that the soil concentrations were typically below PTM
level. Based on the remedial design sampling, the majority of the Boneyard soil
and larger wood and metal debris was deposited in the general Smelter Closure
area.
• Non-PTM Contaminated Soil: Contaminated soil excavated as part of the
source removal actions conducted throughout the Site that was below the
specified PTM levels was disposed in either the CIA or the Smelter Closure. The
decision of which closure would receive contaminated soil was primarily based
on minimizing haul distances, accepting enough material at the Smelter Closure
to meet final capping grades, and the closure schedule for the Smelter Closure
final capping. Once the Smelter Closure final capping began in 1997, the CIA
became the one contaminated soil consolidation area at the Site. The
contaminated soil was placed within and on top of the demolition debris enabling
the surface to be graded and contoured as necessary to accommodate the final
closure grades necessary for capping and long-term surface water control.
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SMELTER CLOSURE
GENERAL DISPOSAL
area>
a" DIA-GOt±
DRAIN PIPE
SM% MIN
:HON
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FIB ERG!
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2% MIN
PTM DISPOSAL
¦CELL LIMITS
SMELTER CLOSURE-
FINAL COVER LIMITS
TYP
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Figure 7
PTM Cell Plan View
BUNKER HILL NON-POPULATED AREAS
-------
I'-O" uw
SEE NOTE 1
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PTM DISPOSAL.
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NORTH LIMIT
PTM DISPOSAL -
SECTION ^AT\
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FIGURE 7
Figure 8
PTM Cell Section
BUNKER HiLL NON-POPULATED AREAS
INITIAL 5-YEAR REVIEW
CONTAINMENT
BfRM
CH2MHILL.
I YPILAL
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1. MAINTAIN MINIMUM 2'-0" SEPARATION
SJETWEEW PTM CELL COVER AND SWEl TF«
CLOSURE FINAL COVER
2,ACTUAL PTM VOLUME IS UNKNOWN
FINAL CONFIG URATjON Of PTM C£LL
COVER WILL DEPEND ON AefUAL PTM
VOLUME.
. COLLECTION
DRAW PIPE
TO CELL aox
2 A MIN
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APPRO* SMEL.TF.ft CLOSURE
FJNAL COVER CRAOES
SOi/TM L *H1T
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/—ITPICA1
t anchor
TRENCH
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
• Slag and A-l Gypsum Pond Materials: As noted above, slag was used as
infill material in voids during placement of the demolition debris. The west
cell of the CIA provided the slag source. When it was realized that the
Smelter Closure could accommodate additional material, a portion of the
A-l Gypsum Pond (Figure 2) was also placed in the Smelter Closure
because of the shorter haul distance in comparison to the CIA.
C. Capping the Smelter Closure
Once the contaminated soil was placed to its final design closure grades the Smelter
Closure area was capped with a geomembrane liner and re-vegetated (CH2M HILL,
June 1997). The closure was capped in two phases spanning two construction seasons,
1997 and 1998. Specific components of the Smelter Closure cap include:
• Closure Configuration and Grading: The 30-acre closure area footprint
was defined by the existing perimeter roads encompassing the Smelter. The
grading plan for the closure was developed to attain the containment volume
necessary for the removal actions and as necessary for stability of the
geomembrane cover layer. Slopes typically ranged between 3:1 to 4:1 and
flatter. The top of the closure area was designed to be adjusted, as necessary
to accommodate either greater or less volumes of consolidated materials.
• Cover System: The cover system consisted of 6 inches of slag placed on top
of the final layer of contaminated material which served as a cushion for the
overlying textured 60-mil HDPE geomembrane; a strip drain system to
collect and convey infiltration to positive drainage outlets; and 12-inches of
drain material (also slag) covered with 12 inches of growth media (a
topsoillike material). The growth media was then re-vegetated.
• Surface Water Management: Surface water management system consisted
of stormwater ditches constructed around the perimeter of the closure,
runoff control berms constructed on top of the cover, and culverts beneath
roadways. The stormwater ditch system was designed and constructed to
prevent run-on onto the closure cap and to collect stormwater and convey it
to one of three adjacent creeks, (Government, Magnet, or Bunker Creek).
D. Re-vegetation of Disturbed Areas
The Smelter Closure cover and disturbed areas in the general vicinity were
hydroseeded upon completion of the construction. Native seed mixes were used that
had proven to be successful at the Bunker Hill site.
E. Borrow Area Development and Future ICP Landfill
To satisfy the "clean" fill (less than 100 mg/kg lead) requirements needed to complete
several of the remediations, a borrow area was developed on a knoll located to
the west of the Smelter (Figure 2) (CH2M HILL, April 1997). Generally, the upper
foot of soil on this knoll did not meet the ICP clean fill requirements, and therefore
was stripped and stockpiled to be used as growth media for the Smelter Closure
vegetative layer. The borrow was used for general site fill in contaminated soil
removal areas, for growth media development, and as grading fill needed for the
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Smelter Closure. The borrow area will also be used as a clean soil source for backfill
and capping when future remediations are conducted in the valley by the local
community.
A future disposal area to be located within the confines of the Borrow Area was
designed by EPA and the State for local community use (CH2M HILL, 2000). The
purpose of this borrow area landfill will be to consolidate contaminated soil and
waste that may be generated by the community ICP program during future
remediations. The borrow area landfill is anticipated to be constructed in 2001.
F. Mc Kin ley Avenue
The April 1998 ESD provides for EPA's participation with the local communities in
the repair of McKinley Avenue once site remediations have been completed. During
the remediation phase, the portion of McKinley Avenue that extends from the edge of
Kellogg to Government Gulch road was closed to public traffic. This portion of the
road received heavy truck traffic as part of the remediation. In light of this, EPA
agreed to compensate the City of Kellogg for $542,530 for the remedial impacts. The
City of Kellogg will be responsible for repairs, upgrades, or reconstruction of
McKinley Avenue in the future as they see fit.
4.3.6.4 Operations and Maintenance Considerations
An O&M plan for the Smelter Closure has not yet been prepared. However, it is anticipated
that O&M activities would include:
Routine inspections of the closure cap vegetation for growth and signs of erosion.
Inspection of ditches, runoff control berms and culverts for erosion and debris
accumulation.
General maintenance such as ditch and culvert cleaning, hydroseeding, and road
maintenance.
4.3.6.5 Assessment of Remedial Action
A. Remedy Performance
The Industrial Complex remedy was constructed in accordance with its plans and
specifications and the ROD requirements. It is performing adequately. In one location
of the Smelter Closure cap, water overtopped a check dam in a drainage ditch and
resulted in an area of erosion on the cap. This check dam, as well as all others, was
removed and the cap was repaired. No further erosion has been noted on the cap, and
the problem is not expected to occur again. Surface water drainage ditches located on
the cap are performing as designed, and are conveying runoff off of the cap. In
addition, water draining along the prior ground surface prior to the consolidation of
demolition debris is being intercepted by the closure toe-drain and is conveyed to the
CTP for treatment.
Routine and annual inspections and monitoring is necessary to verify ongoing
performance (i.e., vegetative growth, erosion of cap, stability of surface water
drainages, ongoing seepage monitoring, etc.).
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B. New Information
EPA, the State, and the ICP continue to determine the regulatory and long-term
management requirements of the future ICP Landfill. The design of this landfill will be
influenced by the regulatory and operations requirements agreed to by the project
stakeholders. As noted previously, this landfill is projected to be constructed during
the year 2001.
C. Deficiencies Identified
No deficiencies have been identified. However as noted in Section 4.2 Site-Wide
Monitoring, data continues to be gathered in the Smelter Closure Observational
Approach monitoring program to evaluate whether down-gradient seepage
collection is necessary for the Smelter Closure.
D. Recommended Improvements
None at this time.
4.3.7 Mine Operations and Boulevard Areas, Railroad Gulch
Drainage
4.3.7.1 Introduction and Background
Historically, the Mine Operations Area (MOA) consisted of land and ore processing
structures bounded on the north by the UPRR and the CTP and on the south by the cut-slope
hillsides leading up to the Bunker Hill Mine (Figure 2). McKinley Avenue bisects the
MOA in the east-west direction. The mining and ore-processing structures and facilities that
were included in this remedial action of the MOA consisted of:
the Powerhouse,
the Concentrator Silo and conveyor system,
the Concentrator Building and trestle system to the CIA,
the mill settling pond, and
two small ancillary office buildings west of the Concentrator Building.
For the purposes of this 5-year review document, the remediation of the Boulevard Area
and improvements to the Railroad Gulch drainage system, both located to the west of the
MOA on the southern side of McKinley Avenue, will also be addressed in this section.
When ore processing was conducted at the Mine Operations facilities, the Boulevard Area
was used as a staging area for concentrates prior to being loaded into rail cars, and
transported to the Lead Smelter. Because the surface water flows from Railroad Gulch
traverse across the eastern portion of the Boulevard Area, the drainage improvements
associated with Railroad Gulch will also be addressed in this section.
4.3.7.2 Review of ROD, ESDs, and Rod Amendment
Table 4-9 summarizes requirements of the ROD and ROD Amendment for the Mine
Operations and Boulevard Areas.
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Table 4-9
Mine Operations and Boulevard Areas Remedial Actions
ROD Requirement
Remedial Action Objective/Goal
Document
1 MOA: Demolish or decontaminate
structures consistent with intended future
use
Prevent direct contact
ROD 9.2.5
2 MOA: Close or remove contaminated soil
from the bottom of the mill settling pond
Prevent direct contact and minimize
infiltration through contaminated
material
ROD 9.2.5
3 MOA and Boulevard: Remove non-PTM
contaminated soils with metal
concentrations greater than 1000 mg/kg
and dispose in the Smelter Closure
Prevent direct contact and minimize
infiltration through contaminated media
ROD 9.2.5
4 MOA: Process, recycle or stabilize PTM
accumulations
Material reuse, minimize material disposed
and prevent direct contact
ROD 9.2.5
5 Boulevard: Dispose PTMs under the
Smelter Closure cap in a fully lined
monocell (this amends ROD 9.2.5 which
required chemical stabilization of PTMs)
Prevent direct contact
ROD Amdt
9.2.5
Performance standards for the remedies include:
Decontamination procedures for offsite salvage that are consistent with the proposed
rule for Best Demonstrated Available Technology (BDAT) treatment technologies for
contaminated debris (Federal Register, January 9,1992).
Management of PCB-containing equipment and other regulated wastes in accordance
with the Toxic Substance Control Act (TSCA) and RCRA.
Management of asbestos-containing materials in accordance with applicable
regulations.
Soil removal goal: Soil with lead concentration greater than 1,000 mg/kg.
• Placement of a minimum 6-inch thick clean fill cap over removal areas if surface
concentrations are greater than 1,000 mg/kg lead in compliance with ICP requirements
for industrial sites. Clean barrier fill is defined as having less than 100 mg/kg lead.
4.3.7.3 Description of Remedial Actions
A. Mine Operations Area
Up until the early 1980's, the facilities had been operational. Since being shut down,
the structures became dilapidated from lack of maintenance as well as from piece-meal
salvage operations by the owners of the MOA. With the bankruptcy of this
owner/PRP, the MOA land and buildings were deeded to Shoshone County as
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payment for back-taxes. As new owners of the land and buildings, the County elected
to demolish all structures.
The design of the MOA demolition and remediation was prepared in the summer of
1994. The MOA remediation included the following activities:
• Characterization and removal of hazardous materials located within buildings.
• Removal of concentrates and ores for reprocessing.
• Asbestos abatement and offsite disposal.
• Wash-down of buildings prior to demolition
• Demolition of buildings and disposal of debris on top of the CIA.
• Contaminated soil removal consistent with the ICP program.
• Site grading and placement of ICP barriers.
• Re-vegetation in designated areas.
EPA and the State of Idaho elected to use a site PRP, the Bunker Limited Partnership,
and its EPA-controlled bankruptcy fund to contract and conduct the remediation.
BLP in turn, hired Rust Environmental as their remediation contractor for the MOA.
The MOA remediation was conducted in the summer of 1994 and completed in early
1995.
The work associated with the waste characterizations, removals, demolition, material
disposal, and placement of protective barriers were all conducted according to
remedial performance goals and plans and specifications.
B. Boulevard Area
The design of the Boulevard Area remediation was prepared in 1996. The remediation
consisted of PTM and contaminated soil removals, replacement with clean soil and
surface water control measures.
The depth of contaminated soil removals generally ranged between one to 6 feet
across the Boulevard Area. PTMs were transported to the Smelter Closure and
disposed in the geomembrane-lined PTM Cell; contaminated soil with lead
concentrations less than PTM-level (84,600 mg/kg) were disposed in the general
Smelter Closure area as in-fill of demolition debris and for closure grading. The final
grading of the ICP barrier over the Boulevard promoted surface water flow to a
roadside ditch constructed parallel to McKinley Avenue with culverts under
McKinley Avenue that eventually conveyed Boulevard Area runoff to Bunker Creek.
C. Railroad Gulch Drainage System
As part of the Site remediation and not specifically cited in the ROD, the portion of
the Railroad Gulch surface water channel that extends across the eastern end of the
Boulevard area, crosses under McKinley Avenue, and then connects to Bunker Creek
was reconstructed to increase flow capacity. This portion of the channel routinely
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flooded onto the Boulevard Area during high-flow spring run-off events and spread
surface contamination throughout the area. The reconstructed channel was designed to
accommodate a 10-year design storm. A conceptual design prepared by CH2M HILL
was modified in the field by oversight personnel from CH2M HILL and IDEQ to fit
site grading conditions (CH2M HILL, 1997). The channel reconstruction work was
conducted using the BLP remediation fund. The channel was lined with riprap and
culverts beneath McKinley Avenue were increased in size to handle the estimated
spring run-off flows. Areas adjacent to the channel that were disturbed during
construction were re-vegetated.
4.3.7.4 Operations and Maintenance Considerations
The O&M considerations for the MO A, Boulevard, and Railroad Gulch remedies will focus
primarily on minimizing the possibility of surface recontamination, and therefore direct
contact with underlying contaminated materials. This will be achieved by maintaining the
integrity of the ICP barriers (either soil, rock, or vegetation) and by maintaining the final site
grading and surface water control systems.
A final O&M plan has not yet been prepared for these areas, however, it is anticipated that
O&M activities will include:
Routine inspection of ICP cap surfaces for evidence of erosion or loss of vegetation.
Routine inspection of drainage facilities (ditches, free-flowing sediment removal in
culverts, ditch rock lining stable, etc.).
Routine maintenance and repair as necessary.
In addition to the routine inspections, inspections after major storms and runoff events
should also be conducted.
4.3.7.5 Assessment of Remedial Action
A. Remedy Performance
The MO A, Boulevard, and Railroad Gulch remedies are performing adequately in that
they were remediated in accordance with design specifications and ROD requirements.
The soil caps in the MOA and Boulevard areas remain intact and serve to prevent
direct contact with underlying contaminated soils. In addition, the rock lined channel
and sediment basin in Railroad Gulch remain fully operational. Routine inspections
and monitoring are necessary to verify ongoing performance (i.e., such as ICP cap
thickness, vegetative growth, and surface contamination levels, and stability of flow
channel).
B. New Information
No new information exists concerning these remedies that would impact their
performance.
C. Remedial Action Deficiencies
No deficiencies in the MOA, Boulevard, or Railroad Gulch drainage system
improvements have been identified as part of this 5-year review.
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D. Remedial Action Improvement Recommendations
No improvements to the MO A, Boulevard, or Railroad Gulch remedies are
recommended as part of this 5-year review.
4.3.8 Central Treatment Plant
4.3.8.1 Introduction and Background
The Central Treatment Plant (CTP) was constructed in 1974 to treat metals-laden acid mine
drainage from the Bunker Hill Mine using a lime precipitation process. The CTP is located
at the base of the southeast corner of the CIA (Figure 2). The Bunker Hill mine water
discharges from the portal of the Kellogg Tunnel, which is located about 1/4 mile up Portal
Gulch. When the ROD was written in 1992, the mine water was pumped out of submerged
mine workings and flowed by gravity to the top of the CIA to an unlined holding pond
prior to being conveyed to the CTP for treatment. Additional metals-contaminated water
from other site sources (runoff from the Zinc Plant, Phosphoric Acid Plant, and the Lead
Smelter) was pumped to the CTP for treatment beginning in the early 1980s. These
additional site flows (often referred to as the 004 flows and the Sweeney Pump Station flows
for the Zinc/Phos Plants and Lead Smelter, respectively) made up only a fraction of the
water treated at the CTP in comparison with the Bunker Hill acid mine drainage.
4.3.8.2 Review of ROD, ESDs, and ROD Amendment
The ROD requires that acid mine drainage be conveyed to the CTP for pre-treatment prior to
additional treatment in a constructed wetland system. As noted in the Smelterville Flats
review (Section 4.3.3), the construction of the wetland treatment system has been deferred
until the effectiveness of the large-scale tailings removal actions across the Site can be
evaluated. Based on this decision, mine water and the minor amount of contaminated site
waters continue to be treated to effluent discharge requirements established by the CTP's
National Pollution Discharge Elimination Standard (NPDES) permit.
Currently, EPA and the State of Idaho are conducting investigations and evaluations that
will result in a separate ROD to address acid mine drainage issues associated with the
Bunker Hill Mine and long-term water treatment needs for the Site. Until this separate ROD
is prepared and issued, the remedial action for the CTP will be one of continuing current
procedures to treat the mine water to required discharge standards and disposal of
treatment plant sludge in a designated unlined cell on top of the CIA (Section 4.3.4.1).
4.3.8.3 Description of Remedial Designs and Remedial Actions
To continue treatment of the Bunker Hill mine water and other contaminated site flows,
EPA and the State decided that it was necessary to improve operational efficiency of the
CTP, conduct more routine maintenance, and potentially upgrade some equipment. In
addition, it was decided to cease the historic practice of placing mine water in unlined
ponds on top of the CIA. As a result of these decisions by EPA and the State, the following
remedial actions have been conducted at the CTP from 1995 to the present:
Construction of a Geomembrane-Lined Holding Pond: Located on McKinley
Avenue to the west of the CTP (Figures 2 and 4); pipelines from the Kellogg Tunnel
and the 004/Sweeney Pump Station were constructed to discharge directly into the
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Lined Pond (CH2M HILL, August 1994). The Lined Pond pump station and piping
conveyed influent directly to the CTP. The purpose of the Lined Pond is to provide
additional water storage capacity, to modulate the flow rate into the treatment plant,
and to provide mixing of flows with various contaminant levels prior to treatment at
the CTP. An additional benefit of the Lined Pond is that mine water no longer needs to
be stored on top of the CIA.
Failure Modes and Effects Analysis of the CTP: Conducted in December 1996 to
identify immediate, near-term, and potential long-term maintenance needs, to evaluate
the impact of various failure scenarios of the CTP, and to prioritize maintenance and
equipment purchase needs (CH2M HILL, January 1997)
90 Percent Design of a New Mine Water Pond and Sludge Holding Facility: In the
spring of 1997, EPA's design contractor prepared 90 percent complete construction
plans and specifications for a new lined pond and sludge facility that was to be
constructed on top of the CIA (CH2M HILL, March 1997). At the State's request, the
construction of this mine water storage and sludge facility was deferred pending the
results of a separate RI being conducted by EPA of the Bunker Hill Mine's acid mine
drainage.
High Density Sludge Pilot Study: Conducted between March and July 1997 to
optimize treatment efficiency and as a means to decrease the sludge volume that would
require disposal (CH2M HILL, December 1997). This pilot study indicated that the
HDS process is a more efficient process but that additional equipment and capital
investment is necessary to operate in the HDS treatment mode.
• Direct Discharge Line from the Mine to the CTP: Constructed by the Bunker Hill
Mine owner in 1997, this direct pipeline to the CTP would enable mine water to
bypass the Lined Pond if desired.
Installation of New Mine Water Discharge Line to the CTP: Constructed in May
1999, this new pipeline was necessary to replace the original line that failed to carry
the necessary volume of mine water flows.
• Miscellaneous O&M Activities:
- Rebuilding the thickener drive-head
- Periodic raising of the sludge impoundment berms
- Closing the east sludge cell
• ICP Barriers on the CTP Property: A minimum 6-inch ICP barrier was placed on
the CTP property (approximately 12.4 acres) in the fall of 1997.
4.3.8.4 Operations and Maintenance Considerations
The responsibility for operating and maintaining the CTP has rested with three different
organizations since the ROD was signed in 1992; two different site PRPs (Gulf /Pintlar) and
the Bunker Limited Partnership, and from 1996 to the present, by the US ACE and their
contractors.
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O&M manuals for the CTP and the Lined Pond were revised and upgraded to optimize the
plant's efficiency in 1997. As mentioned above, EPA is currently preparing to write a separate
ROD that will address the long-term management aspects of the Bunker Hill Mine acid mine
drainage and the CTP. Until that time, O&M activities are expected to continue at their
present level.
4.3.8.5 Assessment of Remedial Action
A. Remedy Performance
Performance of the CTP remedy is measured daily by monitoring the effluent
standards prior to discharge to Bunker Creek. The treatment plant operators are
required by the NPDES permit to take daily samples and submit monthly discharge
monitoring reports. The CTP continues to meet its current discharge standards with
only minor excursions.
The goal of limiting direct contact with contaminants in soils surrounding the CTP has
been achieved by placing 6-inch ICP barriers on the CTP property.
B. New Information
As noted above, a remedial investigation and feasibility study (RI/FS) are currently
being conducted by EPA and the State of Idaho to evaluate options for the long-term
management of acid mine drainage from the Bunker Hill mine. The investigation
includes options for reducing the metals content and amount of mine drainage being
produced by diverting surface water-from the most acid-laden portions of the mine,
upgrades to the current treatment plant, and options for continued sludge disposal. The
unlined sludge disposal cell on top of the CIA is estimated to have only a few years of
remaining capacity. A treatability study is also being conducted to evaluate the
potential for meeting the CTP waste load allocations for lead, cadmium and zinc that
have been issued in a Total Maximum Daily Limit (TMDL) for the South Fork of the
Coeur d'Alene River.
A TMDL for dissolved cadmium, dissolved lead, and dissolved zinc in surface waters
of the Coeur dAlene Basin was jointly issued by EPA and the State of Idaho in August
21, 2000. The TMDL establishes loading capacities, waste load allocations, load
allocation, background conditions, and a margin of safety in accordance with Federal
regulations. Compliance with the new TMDLs would likely require upgrades to the
CTP and changes in operational approaches to treat the water.
C. Identify Deficiencies
No deficiencies were noted.
D. Recommended Improvements
1. The CTP is functioning adequately and in accordance with its treatment and
discharge requirements. However, the plant requires a significant amount of
routine maintenance and upkeep based on the plant's age (constructed in 1974).
The EPA RI/FS being conducted for the Bunker Hill acid mine drainage is also
addressing options associated with the upgrade of the CTP. The RI/FS is
expected to identify additional recommendations for improving the operational
efficiency of the CTP as well as reducing routine O&M costs.
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2. The Lined Pond was designed to have capacity for about 1.5 feet of sediment at
the bottom of the pond prior to it needing to be cleaned out. At the time of this 5-
year review, the sediment in the pond needs to being removed. It is recommended
that this cleaning occur during the spring/summer of 2000.
3. Storage capacity of sludge generated from treatment of water at the CTP is limited
to less that 6 years. The Bunker Hill Mine RI/FS is also evaluating sludge
disposal options. It is recommended to closely monitor the available sludge
capacity remaining in the current disposal pond to ensure that adequate capacity
remains until a long-term storage solution can be put in place.
4.3.9 Bunker Creek
4.3.9.1 Introduction and Background
At the time of ROD preparation, Bunker Creek consisted of a man-made conveyance ditch
that originated near the CTP and flowed west along the base of the CIA. It then angled north
at the western end of the CIA before flowing into a culvert system beneath 1-90 to its
discharge point in the SFCDR (Figure 2).
Prior to its remediation in 1996 and 1997, Bunker Creek received flow from several sources,
including storm drainage from a portion of western Kellogg, effluent discharge from the CTP,
and surface water from Railroad, Deadwood and Magnet Gulches.
Aerial photography taken in the later 1930's indicates that in the Bunker Creek location, a
natural drainage/wetland existed prior to the construction of the CIA. Historical records
indicate that uncontrolled dumping of coarse tailings, fine-grained tailings (slimes), and mine
waste rock occurred in the Bunker Creek corridor, similar to much of the Silver Valley.
Sampling and testing conducted during the. RI indicated that the corridor was moderately to
highly contaminated. Lack of maintenance, sediment deposition from the tributary gulches,
and flow through underlying contaminated tailings all contributed to poor hydraulic
performance and water quality degradation in the Bunker Creek corridor.
4.3.9.2 Review of ROD Requirements
ROD requirements for Bunker Creek are summarized in Table 4-10.
Table 4-10
Bunker Creek Remedial Actions
ROD Requirement
Remedial Action Objective/Goal
Document
1. Channelize and line Bunker Creek
Minimize infiltration through contaminated
material and minimize releases to surface
water
ROD 9.4
2. Treat base flows of Bunker Creek if water
exceeds Federal Water Quality Criteria
Minimize releases to surface water
ROD 9.2.5
3. Remove non-PTM contaminated soils with
lead concentrations greater than 1000
mg/kg and dispose in the Smelter Closure
Prevent direct contact and minimize
infiltration through contaminated media
ROD 9.2.5
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The 1992 Non-Populated Areas ROD specifies that Bunker Creek is to be channelized and
lined. The ROD does- not specify the type of lining (i.e., compacted soil, geomembrane,
concrete, etc.) nor the degree of liner permeability that was intended. In 1995,
TerraGraphics, the State of Idaho's consultant, conducted the subsurface exploration to
determine the nature and extent of contamination in the Bunker Creek corridor as well as the
general geotechnical qualities of the underlying materials. Based on the subsurface
exploration and the planned elevation of the creek bottom, it was decided by EPA and the
State that the in-place soil had an existing permeability sufficiently low enough that a
separate constructed lining for Bunker Creek was not necessary (i.e., the in-place low
permeability soils would perform as a liner). This decision to use the in-place soils as a
natural liner for Bunker Creek was not considered a change to the intent of the remedy, and
therefore, it was determined by EPA that an ESD was not necessary to document this design
change.
The 1992 ROD also states that the Bunker Creek base flows are to be treated in the collected
water wetland should sampling indicate exceedances of Federal Water Quality Criteria
(FWQC).
At the time the ROD was prepared, the collected water wetlands were to be constructed in the
Smelterville Flats area. The April 1998 ESD clarifies that because of a greater focus on
source removals in Smelterville Flats and in other areas of the Site, the wetlands are not
planned for immediate construction in the Flats. The ESD defers construction of the
wetlands in order to provide time to evaluate if the more significant source removals would
result in the wetlands being unnecessary to reach surface water and groundwater goals.
With respect to the quality of Bunker Creek flows, surface water quality measurements are
being taken as part of site-wide monitoring (Section 4.2.1) and flows currently do not meet
FWQC. If monitoring data over time indicates that the large-scale source removals have not
resulted in the Bunker Creek water quality improving to required levels, additional
remedial actions such as treatment of Bunker Creek base flows may be necessary.
4.3.9.3 Description of Remedial Action
The Bunker Creek remedial action was conducted between September 1996 and November
1997. The major elements of the Bunker Creek remedial action included:
Reconstructing approximately 7,600 linear feet of the creek channel, including a low
flow channel and floodplain. The stream reach reconstructed extends from 1-90 to just
downstream of the temporary -road between the CTP and the Christopher son Assay
Lab. The low flow stream channel was rocked for erosion protection; the floodplain
was seeded.
Removing flotation slimes exposed at the surface of channel excavations to a depth of
2 feet below the slimes and backfilling to stream grade with clean compacted backfill
material meeting the ICP requirements of less than 100 parts per million lead.
Disposing excavated slimes on the CIA.
Incorporating non-contaminated excavated material into the grading of the adjacent
floodplain.
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Installing culverts and riprap headwalls for three road crossings to maintain necessary
site access over Bunker Creek.
Placing minimum 6-inch ICP barriers at the surface of all disturbed areas in the
Bunker Creek corridor. As of the time of this initial 5-year review, only the southern
side of the Bunker Creek corridor from about the Lined Pond east to the CTP has
received an ICP barrier. The northern portion of the Bunker Creek corridor will
receive its ICP barrier in 2000 as part of the CIA Closure activities. The area to the
west of the CIA where Bunker Creek flows in a northerly direction will require
capping at the completion of the CIA remedial action (completion planned for 2000).
The CIA construction traffic through this western portion of the Bunker Creek corridor
prevents capping at this time.
4.3.9.4 Operations and Maintenance Considerations
The O&M considerations for the Bunker Creek corridor will focus primarily on minimizing
direct contact with underlying potentially contaminated materials and maintaining the
hydraulic capacity of the creek channel such that surface water flow is unimpeded into the
SFCDR. Maintaining hydraulic capacity of the channel will minimize the quantity of surface
water that may leak down through the natural low permeability layer beneath the channel.
An O&M plan has not yet been prepared for this area. However, it is anticipated that O&M
activities would include:
Routine inspection of ICP cap surfaces for evidence of erosion or loss of vegetation.
• Routine inspection of Bunker Creek channel (free flowing, sediment removal in
channel/ culverts, channel rock lining and riprap headwalls stable, etc.).
Routine maintenance and repair as necessary.
In addition to the routine inspections, inspections after major storms and runoff events should
also be conducted.
4.3.9.5 Assessment of Remedial Action
A. Remedy Performance
Remedy performance for the Bunker Creek corridor is judged primarily on inspections
that focus on the integrity of the ICP barriers, on maintaining the hydraulic capacity of
the channel, and on monitoring water quality. To date, assessment of the remedy has
focused on water quality.
Water quality is monitored quarterly as part of the site-wide monitoring program
(Section 4.2.1). The water quality of Bunker Creek is significantly influenced by the
water on the various creeks and discharges that drain into it (Railroad, Deadwood, and
Magnet Creeks; CTP discharge; surface-water runoff from the perimeter ditches of the
Smelter Closure). Bunker Creek water quality currently does not meet FWQC,
however, this is expected considering that the Bunker Creek remedy and the
remedies of all the other site tributaries that flow into Bunker Creek have only been
in place for one to 2 years. Bunker Creek and the site tributaries are continuing to
stabilize, and less sediment moves downstream now than did prior to creek
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remediations. It will be necessary to continue monitoring water quality of Bunker
Creek and its tributaries in order to gather appropriate data to determine if any
further remedial actions are necessary to meet the water quality requirements for
Bunker Creek.
B. New Information
None noted.
C. Identify Deficiencies
Water quality of Bunker Creek does not currently meet FWQC. However, it is
expected that its water quality will improve over time as the water quality of the
various drainage that flow into Bunker Creek improves as a result of their individual
remedial actions.
D. Recommended Improvements
None noted.
4.3.10 Union Pacific Railroad Rights-of-Way - PRP-lmplemented Remedial
Action
4.3.10.1 Introduction and Background
This remedial action is being conducted by the Union Pacific Railroad with oversight within
the Bunker Hill 21-square mile area by the State of Idaho and EPA.
Approximately 7.75 miles of UPRR ROW run east/west through the Bunker Hill site. The
location of the UPRR within the Site is shown on Figure 2. The width of the UPRR ranges
from 60 to 200 feet. The Wallace Branch of the UPRR, including the portion that runs
through the Bunker Hill site, has been taken out of service and is no longer used to transport
materials. The right-of-way of the railroad is being maintained for recreational uses only.
The rail line was constructed in the late 1800s and transported mining products to and from
the Coeur dAlene River Valley. Mine tailings and waste rock were prevalent in the valley
from the mining activities that date to the last 20 years of the 19th century. In portions of the
UPRR, these lead-bearing materials were used in the construction of the original rail bed.
Lead-bearing mine tailings and concentrates may also have been deposited on portions of
the UPRR from historical flood deposition as well as from occasional spillage from the rail
cars. On the basis of results of sampling in the Bunker Hill site, the UPRR was not identified
as an active contributor of lead to the environment (AGI, 1991). Accumulations of lead-
bearing materials were essentially confined to the ballast area beneath the track.
4.3.10.2 Review of ROD, ESDs and ROD Amendment
The majority of the UPRR is located in the non-populated area of the Site; however, portions
of the UPRR are adjacent to populated areas such as commercial and residential areas of
Smelterville and Kellogg. The portions of the UPRR that are adjacent to the Populated Areas
of the Site are further discussed and evaluated in the Bunker Hill Populated Areas Operable
Unit First Five Year Report. Since the portions of the UPRR are located in both areas, the
ROD specified that remedial action for rights-of-way in residential areas must meet the
requirements of the Residential Soils ROD. The Non-Populated Areas ROD states that
ROWs in the Non-Populated Areas of the Site will be capped in most instances (ROD, 9.2.6).
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Remedial actions specified in the ROD are summarized below in Table 4-11. For reasons
cited above, requirements from both the Non-Populated Areas ROD and the Residential Soils
ROD are included in Table 4-11.
The Residential Soils ROD sets a threshold level for lead concentrations in soils of
1,000 mg/kg. Criteria for removal and replacement of soil according to the Residential Soils
ROD is as follows:
If the 0- to 1-inch or 1- to 6-inch-depth intervals exceed the threshold level, 6 inches
of contaminated material will be excavated and replaced. In addition, if the 6- to
12-inch interval exceeds the threshold level, another 6 inches (total of 12 inches) will
be removed and replaced. If the 6- to 12-inch interval does not exceed the threshold
level, the property will have a 6-inch excavation and replacement.
In the case where the 6- to 12-inch-depth interval exceeds the threshold level-but the
0- to 1-inch and 1- to 6-inch intervals do not, 12 inches of material will be excavated
and replaced.
• If the 0- to 1-inch and the 1- to 6-inch and the 6- to 12-inch intervals do not exceed the
threshold level, the property will not be remediated.
Table 4-11
UPRR Remedial Actions
Remedial Actions
Remedial Action
Objectives/Goals
Success
Criteria
Document
Source
UPRR in Populated and Non-Populated Areas
Temporary dust control
Minimize lead exposure
from fugitive
Meet ambient air criteria
ROD 9.2.6
Enforce existing controls on access
Prevent direct exposure to
contaminated soil
Reduce the potential for
unauthorized access
ROD 9.2.6
Maintain existing fencing
Prevent direct exposure to
contaminated soil
Reduce the potential for
unauthorized access
ROD 9.2.6
Institutional controls
Prevent direct exposure to
contaminated soil
Reduce the potential for
accidental exposure
ROD 9.2.6
Permanent dust control through
containment,"hot spot" removal, soil/rock
barriers, and re-vegetation
Minimize lead exposure
from fugitive dust
Meet ambient air criteria
ROD 9.2.6
Additional Action for UPRR Adjacent to Residential Areas
Treat consistent with the remedial action
selected in the Residential Soils ROD
Minimize lead exposure
from fugitive dust; prevent
direct exposure to
contaminated soil
Meet ambient air
criteria;
reduce the potential for
accidental exposure
ROD 9.2.6
The 1977 Annual Remedial Action Implementation Plan for Remedial Actions Along the
Union Pacific RailroadRights-of-Way (MFG, April 1977) (the 1997 Implementation Plan )
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states that the ROD requires removal from the UPRR of process material having measured
lead concentrations exceeding levels typically associated with mine tailings or waste rock. In
accordance with this requirement, concentrate, ballast, and soils with lead concentrations
exceeding 30,000 mg/kg and not attributable to mine tailings or waste rock were to be
excavated from the UPRR and disposed. In addition, all portions of the UPRR with lead
concentrations in excess of 1,000 mg/kg in the top 12 inches (or 6 inches, depending on
location) of ballast or soil were to receive either barrier placement, removal, replacement (if
necessary, to maintain drainage), re-vegetation, and/or access control, dependent on
geographic location and current land use.
4.3.10.3 Description of Remedial Actions Conducted at the Site
Work first began on the UPRR in 1995. Under an agreement with EPA and the State of Idaho,
some portions of the UPRR would be remediated by EPA and the State in exchange for use of
the UPRR for construction of a haul road to transport mine tailings from Smelterville Flats to
the CIA. Other portions of the right-of-way would be remediated by UPRR as part of their
Consent Decree with EPA. Remediation of the UPRR right-of-way extended from 1995
through 1999. Yearly activities included the following:
1995
Areas of concentrate ("hot spots") were identified and removed, transported to the Smelter
Complex, and placed in storage for eventual disposal in the Smelter Closure area.
The UPRR was subdivided into 250-foot segments to establish a basis for sampling. Sampling
and analysis was conducted to determine where and to what depth excavation along the UPRR
would occur (soils near the Concentrator Building of the Mine Operations Area were to be
removed to a depth of 18 inches).
Dust control was performed in 1995 and in each subsequent year until remediation was
completed in 1997.
1996
Rails, ties, and other track material were removed prior to ballast and soil excavation;
decontaminated materials were shipped offsite for reuse; contaminated or unusable materials
were disposed in the CIA.
After rail and tie removal, excavation occurred in all or portions of the UPRR from Kellogg
on the east side of the Bunker Hill site to the west where the UPRR goes beneath 1-90 near the
Pinehurst Narrows; verification sampling proceeded concurrently with excavation activities.
Excavated materials from most areas were disposed in the CIA; potential PTM materials from
the concentrator and other areas were stockpiled and sampled and those identified as PTM
materials were transported from the CIA to the PTM cell at the Lead Smelter site.
Clean soil barriers (less than 100 mg/kg lead) were placed along UPRR adjacent to or near
residential areas in Smelterville.
A portion of a residential yard in Smelterville and a landscaped area in front of the Kellogg
Lumber commercial facility in Kellogg were remediated since they were located on the
UPRR.
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1997
Railroad ties remaining from the 1996 removal were sorted and either decontaminated for
reuse or disposed in the CIA.
Excavation, disposal, verification sampling, and barrier installation continued along the
remaining portions of the UPRR that needed remediation except those to be remediated by
EPA and the State of Idaho.
1998 - 1999
Verification sampling was completed on areas remediated by UPRR; cover material was
added to deficient areas.
The majority of work was completed by EPA and the State of Idaho on the portion of the
UPRR that was used as a haul road for the CIA.
There are several types of areas along the UPRR that were determined to be no action areas.
No action areas were defined as those areas of the UPRR with total lead levels that exceeded
the action level of 1,000 mg/kg, but where physical conditions precluded remediation. The no
action areas included river embankments, hillside areas, paved areas, submerged portions of
Page Swamp, and densely vegetated areas. River embankments and paved areas were no
action areas because they already had effective barriers of riprap and pavement, respectively.
Hillside areas were no action areas because they either consisted of rock outcrops or were well
vegetated. Excavation or barrier installation on a rock outcrop could have resulted in slope
instability. Excavation or barrier installation on vegetated hillsides or other densely vegetated
areas was not recommended because of the difficulty in reestablishing the vegetation.
Approximately 7,000 feet of the UPRR is adjacent to the north boundary of Page Pond. The
toe of the slope of the south portion of the UPRR in this area is either submerged or heavily
vegetated. The submerged areas of this embankment were determined to be no action areas
because they will be addressed as part of the Page Pond remedial action.
According to the Letter Report for Submittal of Sampling Results for Union Pacific Area 5-Yr.
Review Rights-of-Way Sampling at the Bunker Hill Superfund Site (MFG, June 1999) (the
1999 Sampling Report), some areas of the UPRR still remain to be remediated by EPA and
the State of Idaho. Verification sampling needs to be completed by EPA and the State of Idaho
along the portions of the UPRR that were used for the CIA haul road. Crossings of the
UPRR that allow access to the CIA are located between Smelterville and Government Gulch
Road, east of Government Gulch Road adjacent to McKinley Avenue, and near the west side
of the Concentrator area. These crossings will most likely become permanent. The crossing
between Smelterville and Government Gulch Road and the crossing near the west side of
the Concentrator area have been paved. The crossing between east of Government Gulch
Road adjacent to McKinley Avenue is planned for paving. This work that remains to be
completed by EPA and the State of Idaho on areas of the UPRR is scheduled for completion
in 2000.
Although not required as part of the UPRR remedial action, it should be noted that the
portion of the UPRR from Smelterville through Kellogg to Elizabeth Park has been paved as
part of trail construction. Paving of remaining areas of the UPRR within the Bunker Hill site
is currently under consideration.
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Detailed mapping of the work along specific segments of the UPRR, of the no action areas,
and of the areas remediated by EPA and the State of Idaho is provided in the 1999 Sampling
Report.
4.3.10.4 Operations and Maintenance
Proposed O&M activities for the UPRR are presented in the Bunker Hill Superfund Site Union
Pacific Area Remedial Action Work Plan (MFG, March 1995) (the 1995 Work Plan). Annual
inspections of areas capped with a rock barrier and areas capped with a re-vegetated soil
barrier will be conducted by Union Pacific Railroad representatives until ownership of the
UPRR is transferred to other parties. If areas of rock barriers are found to be disturbed or
eroded, they will be repaired using additional rock or other barrier material depending on site
specific needs. Re-vegetated soil barriers will be similarly repaired if they are found to be
disturbed or eroded. If re-vegetated areas are found to be inadequately re-vegetated within 3
years of seeding, they will be reseeded by Union Pacific representatives and inspected until
re-vegetation is completed. Additional O&M activities will include preparation of a Post
Closure O&M Plan with a UPRR annual inspection procedure that includes a checklist of key
inspection criteria. An O&M plan for some portions of the UPRR outside of the Bunker Hill
site has been prepared, and the general contents of this plan are similar to the plan proposed
for portions of the UPRR within the Site boundary.
4.3.10.5 Assessment of Remedial Actions
A. Remedy Performance
According to the maps presented in the 1999 Sampling Report, remediated areas of
the UPRR have been remediated in accordance with the requirements of the ROD, the
1995 Work Plan, and the 1997 Implementation Plan. In 1999, data was collected from
32 sampling locations along the UPRR. The analytical results of sampling the UPRR
presented in the 1999 Sampling Report indicate that none of the areas sampled
exceeded the 1,000-mg/kg threshold concentration for lead. Two samples had
elevated lead concentrations (Table 4-12), however these concentrations were well
below the 1,000-mg/kg threshold concentration.
Barrier depths were also determined at each sampling location. The majority of
barrier depths met or exceeded the prescribed barrier thickness, however barrier
thickness deficiencies were identified at seven locations (Table 4-13).
In general the remedy is meeting performance standards and cleanup goals since none
of the sampled areas exceeded the 1,000-mg/kg threshold lead concentration.
However, seven of the areas sampled for barrier thickness does not meet prescribed
barrier thickness requirements.
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Table 4-12
Samples with Highest Lead Concentrations
(Concentrations in mg/kg)
Sample ID
Segment ID
0 -1 Inch Deep
1-6 Inches Deep
General Location
99-004
012
603
688
East of Ross Ranch
99-017
CA-1
549
490
Concentrator Area
Table 4-13
Identified Barrier Deficiencies
Sample
ID
Segment
ID
Prescribed Barrier
Thickness (in.)
Measured Barrier
Thickness (in.)
General Location
99-001
001
12
10.5
Elizabeth Park
99-005
015
12
9.5
Ross Ranch
99-008
021
12
6
Near Ross Ranch
99-009
026
12
11
East Kellogg
99-023
080
12
11
Smelterville
99-024
085
12
9.5
Smelterville
99-030
150
6
4.5
Near West End of the Site
B. Deficiencies Identified
The results presented in the 1999 Sampling Report identify seven segments of the
UPRR that apparently have barriers that do not meet prescribed barrier thickness
requirements. The locations of these segments are presented in Table 4-13.
Since work on the UPRR has not been certified, the UPRR has not yet been
incorporated into the ICP. The ICP has formal procedures for monitoring
construction and other activities on remediated areas of the Site. Since the UPRR is
not covered by the ICP, utility crossings have apparently not been monitored
carefully and the potential for recontamination by other activities, such as placement
of snow removed from contaminated residential areas on the UPRR, has not been
adequately assessed.
The information and evaluation of the potential for contaminant tracking due to lack
of access controls along the UPRR that may impact protectiveness of the Populated
Areas of the Bunker Hill site, please refer to the Bunker Hill Populated Areas
Operable Unit First Five Year Report.
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C. Recommended Improvements
Segments of the UPRR with barriers that apparently do not meet thickness
requirements should be assessed in the following manner:
• Re-sample each deficient segment to verify that the barrier thickness is as
reported in the 1999 Sampling Report
• For segments with confirmed barrier thickness deficiencies, evaluate the
magnitude of the deficiency, the potential impact of the deficiency on
protectiveness, and the need for additional remedial action
• For segments that are identified as needing additional remedial actions, prepare
a plan for the proposed remedial actions and implement the plan
• Conduct confirmation sampling during or following plan implementation to
verify that barrier thickness requirements have been met
Since the majority of the UPRR remedial action has been completed, Union Pacific
should proceed with preparation and implementation of the O&M plan discussed in
the 1995 Work Plan. In addition to discussing inspection and maintenance of the
UPRR, the plan should also address the requirements of the ICP and the transfer of
O&M responsibilities to new owners.
To prevent recontamination of the UPRR, an interim program needs to be developed
to manage construction and other activities occurring within remediated areas of the
UPRR. This program should be similar to the existing ICP and should be maintained
in place until remedial actions are certified as complete and the UPRR is
incorporated into the ICP.
4.3.11 Milo Gulch and Reed Landing Remedial Action
4.3.11.1 Introduction and Background
Milo Creek drains an approximate 4-square mile watershed located above and into the towns
of Wardner and Kellogg and eventually discharges into the SFCDR. For the purposes of this
initial 5-year review document, the Milo Creek watershed will be discussed in two segments,
the upper watershed and the lower Milo Creek piping system beneath the towns of Wardner
and Kellogg.
A. Upper Milo Watershed
Figure 9 shows the upper Milo Creek watershed that comprises about 2 square miles
and consists of forested and clear-cut areas, mine dumps, and some industrial mining
areas (the Reed Landing). In the upper reaches of the basin, there are three forks of
Milo Creek (West, South and Upper) that join to form the main stem of Milo Creek.
Prior to the remediations discussed in this report. Milo Creek flowed in a steep narrow
canyon with heavy bedload (sediment, gravel, and rocks transported downstream by
the force of water). The watershed crest at Wardner Peak is at approximately 6,300
feet mean MSL and drops to 2,300 feet MSL in Kellogg.
Historically, the upper Milo Creek watershed primarily supported mining and
logging. Mine dumps, portals, access roads, hoists, and other industrial mining
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features are located throughout this area and have impacted Milo Creek's water quality
and discharge over the years. A large surface depression resulting from underground
block caving mining techniques is located in the western portion of the upper Milo
watershed and is referred to as the Guy Cave Area. West Milo Creek flows into this
surface depression and into the underground mine workings. In addition, several faults
are located in the upper Milo watershed that cross the various forks of Milo Creek. It is
believed that these fault zones and the close proximity of the extensive mine workings
beneath this area result in significant surface water infiltration into the mine workings.
This clean surface water is then changed through chemical reactions with pyrite and
oxygen to acid mine drainage that eventually requires treatment at the CTP.
The Reed Landing consists of a mine dump located midway up the watershed that
filled Milo Creek in the early days of the Bunker Hill Mine Complex. A 4x4 box
concrete culvert conveyed Milo Creek through the dump or "landing." A screen or
"grizzly" made of railroad rails was placed over the entrance of the box culvert to
restrict bedload (rocks and woody debris) from entering the culvert. During flood
events, a backhoe would remove debris from the grizzly to ensure that water could
enter into the culvert. During the 1997 flood event that caused substantial damage to
the downstream infrastructure for Milo Creek, debris overwhelmed the backhoe's
ability to keep the grizzly clear and it overtopped the culvert. Discussions with
workers at the scene suggested that debris, not flood water, was the major cause of
problems at the Reed Landing. One exception was a roof cave-in of the box culvert
that was repaired by the Mine Owner. This repair was consistent with the Mine
Owner's responsibility to operate and maintain the Reed Landing and it's components,
including the approximately 100-foot high crib wall that held up the northern face of
the mine dump and the 4 x 4 box culvert.
A second grizzly structure was constructed in Milo Creek approximately 300 feet
above the town of Wardner to screen excessive bedload prior to flow entering the
48-inch corrugated metal pipe system that conveyed Milo Creek beneath Wardner and
Kellogg.
B. Lower Milo Creek Piping System
As Milo Creek enters the town of Wardner at the lower grizzly, it flowed underground
through a combination of open channels, 48-inch concrete pipe, 48-inch corrugated
metal pipe, and 4-foot by 4-foot box culverts. Through the town of Kellogg, Milo
Creek was totally contained by similar piping materials as those used through Wardner.
Severe flood damage to the existing Lower Milo Creek piping system occurred during
a major runoff event in May 1997. Debris accumulations plugged the grizzlies and
eventually resulted in failure of the Milo Creek subsurface conveyance structures
downstream in Kellogg. Heavy bedload and debris plugged culvert and pipe systems
and resulted in several blowouts of culverts, pipe failures, and the creation of
sinkholes. In addition, lead-contaminated surface water flooded through many
properties and recontaminated areas that had previously been remediated as part of the
Populated Areas residential soil ROD. The affected properties were remediated by the
Federal Emergency Management Administration (FEMA) and
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Idaho Bureau of Disaster Services (BDS) under a Presidential Declaration. More than
$500,000 in remedial activities were required to remove the contaminated sediment
from properties in Kellogg.
4 3.11.2 Review of ROD, ESDs, and Rod Amendment
Requirements for the Milo Gulch and Reed Landing are summarized in Table 4-14.
Table 4-14
Milo Gulch and Reed Landing Remedial Actions
ROD Requirement
Remedial Action Objective/Goal
Document
1. Channelize and line Milo Creek from the
Wardner Water System intake to the
culvert that directs flow beneath
Wardner and Kellogg
1. Minimize contact between Milo Creek
surface water, tailings, and waste rock on the
gulch floor
2. Reduce contaminant transport to the
SFCDR as suspended sediment in runoff
events
ROD 9.2.1
ROD 9.2.1
3. Minimize surface water infiltration into the
underlying Bunker Hill mine workings
ROD 9.2.5
2. Financial contribution to the
reconstruction of the underground Milo
Creek pipeline project beneath Wardner
and Kellogg
Minimize the potential for recontamination of
previously remediated residential yards.
ESD 4-98
As noted in the above table, the April 1998 ESD modifies the upper Milo Creek remedy by
including EPA participation in the reconstruction of the underground Milo Creek pipeline
system beneath Wardner and Kellogg. As noted above, the pipeline system was damaged and
breached in May of 1997 during a flood event resulting in the recontamination of
approximately 50 remediated yards and over 5 miles of right-of-way in Wardner and Kellogg
with soil and sediment containing up to 14,000 mg/kg lead. Costs associated with
remediation of the recontaminated areas was estimated at about $500,000. The cost to replace
the pipeline system was estimated at $10 million, toward which EPA contributed $2,000,000.
The State of Idaho managed the implementation of this multi-agency-funded project through
the Bureau of Disaster Services and other State agencies.
4.3.11.3 Description of Remedial Actions
A. Removal of Waste Rock and Tailings from Portions of the Milo Creek
Basin
A mine waste rock and tailings removal project within the stretch of Milo Creek
between the Water District dam and the Reed Landing grizzly was conducted in the
fall of 1995 by the Bunker Hill mine owner. EPA and the State of Idaho participated
in scope discussions with the mine owner and agreed that the tailings removal action
would meet the objectives of the ROD for Milo Creek (minimize contact of surface
water with contaminants and reduce contaminated sediment transport to the
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SFCDR). Approximately 30,000 cubic yards of mine waste and tailings were removed
from the creek bank areas (a 50 percent increase over ROD estimated removal
quantities). These materials were transported to the Guy Cave and used as backfill in
this surface depression as a means to improve grading in this area.
B. Upper and Lower Milo Creek Improvements
A water diversion project was implemented in the latter part of 1998 through 1999 on
the main stem of Milo Creek for the purposes of minimizing contact between Milo
Creek surface water and tailings/mine waste rock on the valley floor and to reduce
infiltration into the mine workings that underlie the stretch of Milo Creek between the
confluence with the South Fork of Milo Creek and Reed Landing. This water
diversion piping project satisfies the ROD requirement to line Milo Creek.
This project was partially funded by EPA and FEMA as a response to the flooding that
occurred in the spring of 1997. This Milo Creek diversion project consisted of
installing a new diversion dam above the existing Wardner Water District dam and
hard-piping the flow from the upper and main stem of Milo Creek down to another
diversion structure located at the Reed Landing. From the Reed Landing structure, the
Milo Creek flow is piped down to the Upper Wardner structure prior to discharging
into a new piping system beneath the towns of Wardner and Kellogg. Based on
funding constraints, this surface water diversion system was designed for a flood
recurrence interval of between 2 and 5 years maximum. The twin 54-inch pipes that
flow beneath Wardner and Kellogg were designed for a 100-year recurrence interval.
C. Reed Landing
In 1999, EPA, the State of Idaho, and the US ACE implemented a remediation project
at the Reed Landing area to enhance the area's drainage capacity and to increase the
stability of the landing. Because of the poor structural condition of a downstream 4-
foot by 4-foot overflow culvert, it was believed that the failure of this culvert could
result in overland flow across the Reed Landing and significant erosion of the mine
waste rock and tailings that contained in the Landing. The Reed Landing project was
designed to mitigate this potential for overland flow by constructing an overflow
channel down the Reed Landing that made the existing overflow culvert unnecessary.
The Reed Landing remediation project included the following components:
Removal of the timber crib-walls and regrading the nearly vertical face of the landing
to at least 2 horizontal to 1 vertical (2H: IV). Excess soil from the regrading (mine
waste rock and tailings predominantly) were transported to the Guy Cave and used for
backfill to enhance surface water drainage in this area. This area is recommended to
be evaluated to determine if a clean soil cap over the waste material is necessary.
Construction of a reinforced concrete channel across the Reed Landing fill that has an
average width of 8 feet and average channel wall height of 5.5 feet. The channel
alignment had two horizontal curves that were banked and super-elevated as necessary
to confine the flow in the channel. A stilling basin was constructed at the
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downstream end of the channel to dissipate energy prior to the creek entering a
700-foot long riprap lined channel that was constructed to join the existing Milo Creek
drainage.
Incidental items such as debris trash-racks and debris basins were also constructed on
the upstream end of the Reed Landing.
4.3.11.4 Operations and Maintenance
A watershed district was formally established in 1998 by a vote of people residing in Kellogg
and Wardner. The district, which is managed by three directors, has the responsibility to
conduct regular O&M activities as necessary to insure the Milo Gulch stormwater control
system continues to function as designed. Funding for the activities is provided by annual
property assessments. A formal O&M plan is being prepared that will likely include:
Periodic inspection and clean out of culverts, sedimentation basins, and diversion
structures.
Inspection of entire gulch after major storm events.
Inspection, and repair if necessary, of damage to channels or structure.
Inspection, and repair if necessary, of fences and other safety features.
Inspection and repair if necessary, of maintenance access routes.
4.3.11.5 Assessment of Remedial Actions
A. Remedy Performance
As noted above, the Milo Gulch remedies were constructed between 1995 and 1999.
The performance of drainage systems such as those installed in Milo Gulch and at the
Reed Landing (especially the natural channel portions) require a period of years to
evaluate the effectiveness as the system incurs varying storm events.
However, both the Milo Creek water diversion and Reed Landing projects were
implemented according to design plans and specifications, and have to date performed
as designed. These projects, including the removal of waste rock and tailings from
portions of the Milo Creek Basin, have minimized contact of surface water with
contaminants, and reduced the potential for contaminated sediment to be transported
downstream. It is recommended that ongoing monitoring continue to gather data to
evaluate remedy performance and whether modifications to the remedy are necessary.
B. New Information
As discussed in Section 4.3.8 of this report, EPA is currently evaluating additional
remedial actions that may be implemented in the upper Milo basin to further reduce
surface water infiltration into the underlying mine workings. The potential additional
remedial actions would focus on diverting the surface water flows of the West and
South Milo Creek around existing fault zones and bypassing the Guy Cave area. If it
is decided to implement these remedial actions, they will not be part of the
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Non-Populated Areas ROD, but rather a separate ROD to specifically address the
Bunker Hill mine water and long-term treatment needs at the Site.
C. Identify Deficiencies
No deficiencies were noted with respect to the Milo Gulch and Reed Landing
remediations.
D. Recommended Improvements
Evaluate whether a clean cap is necessary on the contaminated materials disposed in
the Guy Caves area.
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5.0 5-Year Review Findings and
Recommendations
5.1 Identification and Review of Newly Promulgated or
Revised Regulatory Standards
The remedies selected in the ROD are intended to be protective of human health and the
environment and to comply with Federal and State standards that are applicable or relevant
and appropriate requirements (ARARs). As part of this initial 5-year review, the ARARs
identified in the 1992 Non-Populated Areas ROD were reviewed and any changes or newly
promulgated standards were identified and summarized in Appendix A.
As discussed in Appendix A, there are revisions to existing Chemical-Specific ARARs or to
be considered (TBC) documents initially identified in the ROD, as well as newly identified
Chemical-Specific regulations or TBCs. These are further reviewed below. There were no
identified changes to Action-Specific or Location-Specific standards that were determined to
affect the protectiveness of the remedy.
5.1.1 Air
The 1992 ROD identified standards for particulate matter 10 micrometers (|im) in diameter
or smaller. Since that time standards have also been issued for particles smaller than 2.5 |im.
EPA has determined that these new standards do not affect the protectiveness of the remedy.
For the following reasons these new standards are not being adopted as ARARs for the site:
1. The remedial actions selected in the ROD and being implemented at the site include
removal and containment that will isolate contaminated material from high winds.
Therefore, following completion of the remedial action, contaminated dust and dirt
should be significantly reduced and no longer available to pose an unacceptable risk to
human health regardless of which particulate matter standard is used.
2. While remediation is ongoing, the trigger for taking action to reduce construction related
dust at the site is based on a no visible dust standard. This standard is not tied to, or
dependant upon, any particulate diameter. However, five air monitors located
throughout the site do collect near real-time air quality data including collection of
particulate matter 10 |im in diameter and smaller. This data is available for public
viewing on a website at http://www.bunkerhillair.org. This data, which also includes
meteorological information, is reviewed by onsite contractors during implementation of
construction activities to assist in determining the necessary frequency of dust
suppression efforts at the site. The data is also reviewed by EPA to evaluate any trends
over time, e.g., seasonal variations in dust levels. See Section 4.2.1.3 B of this
document for more information on the air monitoring program. The collection of
particles smaller than 2.5 |im in diameter would not affect the specific remedy that is
being implemented because dust management practices are already being instituted as
part of the remedy
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because dust management practices are already being instituted as part of the remedy
construction process. These dust management practices are being tracked and amended as
discussed above.
5.1.2 Soil and Dust
The 1992 ROD identified several policy level and guidance documents as "To Be Considered"
(TBC) materials in the selection of acceptable lead levels in soil. The-ROD, however, did not
identify specific soil action levels, but rather the type of remedial action to be accomplished
based on the contaminant source, type, volume, and area of the site. For example, remedial
activities conducted at the site include the removal of highly contaminated materials from the
mineral processing facilities, visual removal of tailings in and around stream beds and banks,
stabilization of contaminated soils in steeply sloped areas likely to experience erosion, and
capping of high volume, low concentration materials that is more appropriately managed by
containment technologies. For this reason, the soil lead TBC material identified in the ROD
did not directly affect the cleanup actions taken in the non-populated area of the site.
Nonetheless, because soil and dust TBC material was included in the ROD, any revisions or
updates to these previously identified materials are also included in Appendix A. As the
originally identified TBC materials did not directly affect the cleanup actions taken, the
revisions or updates do not affect the protectiveness of the remedy and therefore are not being
adopted at the current time as TBCs for the site.
5.1.3 Groundwater and Surface Water
In the 1992 ROD, EPA determined that the federal water quality criteria for human health
protection for the ingestion of organisms (fish) and the chronic aquatic life water quality
criteria under the Federal Clean Water Act were applicable with regard to on-site surface
waters for antimony, arsenic, beryllium, cadmium, copper, lead, zinc, mercury, and PCBs. For
groundwater, the cleanup levels specified in the ROD for site-wide groundwater were
maximum contaminant levels (MCLs) and MCL goals for arsenic, copper, lead, mercury,
PCBs, selenium, silver, zinc, and nitrate as identified under the Safe Drinking Water Act. The
ROD further defined contingency measures to be implemented if these cleanup goals were not
capable of being met. It also defined an ARAR waiver process that would be pursued if the
contingency measures were unsuccessful.
Since the ROD was written, several new groundwater and surface water quality criteria or
standards have been developed and are identified in Appendix A. In addition, as noted in
section 4.3.8 of this report, a Total Maximum Daily Load (TMDL) for dissolved cadmium,
lead and zinc in surface waters of the Coeur dAlene Basin was jointly released by EPA and
the State of Idaho on August 21, 2000. The TMDL establishes long-term water quality goals
for discrete (e.g., discharging from a pipe) and non-discrete (e.g., waste piles and floodplain
tailings) sources of metals contamination to the SFCDR. A specific amount of allowable
metals loading has been established for the Bunker Hill Central Treatment Plant (a discrete
source) and is further discussed in Section 4.3.8 of this report. Non-discrete sources in the
Coeur dAlene Basin have not been assigned specific allowable loadings. Rather, a single
allocation has been assigned to all non-discrete sources within various segments of the
SFCDR. At the current time, it is uncertain how the TMDL will be applied at the Bunker Hill
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21-square mile area. In addition to the Bunker Hill 21-square mile area, two other EPA
investigations are currently ongoing (the Basin RI/FS and the Bunker Hill Mine Water RI/FS)
for which this issue is also important and that require coordination with the non-populated
area of the Bunker Hill 21-square mile area. Therefore, EPA is not making a determination at
this time as to the status of the TMDL as an ARAR or TBC, or how it could be applied in the
non-populated area of the site. An analysis of this issue will be conducted in the future, and a
determination made then (see Table 5-2). This analysis will also compare the surface and
groundwater ARARs identified in the ROD to the new ground and surface water quality
criteria or standards identified in Appendix A. The status of these new criteria and standards
as ARARs or TBCs will also be addressed. Upon review of the analysis, if EPA and DEQ
determine that the protectiveness of the remedy is called into question by the new standards,
criteria or limits identified above, any new ARARs or TBCs would be adopted through an
appropriate decision document.
5.2 Assessment of Remedial Actions
Table 5-1 provides a summary of this initial 5-year assessment for the Non-Populated Areas of
the Site. Included in the table are dates during which particular activities or remedial actions
were conducted, work that is remaining to complete the remedial action, a general assessment
of the performance or protectiveness of the remedy, and any deficiencies noted during this
5-year review.
5.3 Recommendations and Required Actions
Table 5-2 summarizes recommendations and required actions that have been identified during
this initial 5-year review. These recommendations and actions were identified to improve
remedy performance or protectiveness in alignment with the Remedial Action Objectives and
performance standards for this Site. Specifics of these activities, if not provided for in the
ROD, the ROD Amendment, or in either of the two ESDs, may need to be documented in a
separate decision document.
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-1
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Activity
ICP Program within
Non-Populated Areas
1994 - present
As part of individual
RAs, placement of ICP
barriers and fences at
various Site locations
As has been conducted to date,
EPA, IDEQ, and USACE will
continue to provide oversight of ICP
related work in the Non-Populated
Area of the Site
None noted.
Health and Safety
During Remediations
1994 - present
Ongoing
Successful implementation of safety
programs as evidenced by no lost
time or injuries reported for prime
contractor
None noted.
Operations and
Maintenance of
Remedies
1994 - present
Day-to-day O&M
currently provided by
subcontractors to
USACE.
O&M being performed adequately.
None noted.
1999-2000
IDEQ in process of
preparing Site-Wide
O&M Plans. All O&M
responsibilities
eventually turned over to
IDEQ.
Not applicable (NA)
NA
Site-Wide Monitoring
1987-1993
1996-present
Ongoing monthly and
quarterly programs,
yearly trend analysis
reports
Insufficient data exists at this time to
establish trends between data and
effectiveness of remedies.
None noted.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-1
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Hillsides Monitoring
Program
1999 - present
Ongoing monitoring,
annual reports and
workshops to discuss
data modifications to RA
approach, if necessary
Adaptive management approach
working adequately.
None noted.
Smelter Closure
Observational
Approach
1997 - present
Ongoing monthly sampling,
yearly trend analysis
reports
As expected, insufficient amount of
post-remediation data to conclusively
determine trends at this time.
None noted.
Remedial Action
Hillsides RA
1987-1993
(PRPs)
1996-present
(Fund-lead)
None
Re-vegetation programs
planned through 2001,
adaptive management
afterwards.
Upper Industrial Landfill
yet to be removed.
Terracing was effective. Planting
was marginally effective.
Adaptive management approach
working adequately. Raveling
hillslopes above Smelterville and
Wardner residential areas may
need additional monitoring and/or
cleanout to reduce potential for
recontamination.
None noted.
None noted.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-1
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Gulches RA
Grouse: 1997
None noted.
All Gulches:
Govt: 1996-
1998
Magnet: 1995-
present
Lower Gov't Creek re-
alignment. Riparian
planting.
Lower Magnet Creek
channel through A-4
gypsum pond.
Access control throughout gulches
and hillsides should be evaluated to
determine appropriate level of
concern (i.e., trail bikers have been
reported to use Grouse Gulch for
recreation).
Determine need for access
restriction and if current access
is deficient implement greater
controls.
Deadwood:
1995-1998
Riparian planting.
Remedies are performing as
expected. Creek channels are
expected to become more stable
with time.
None identified.
Smelterville Flats RA
1996-1998
1999 - present
Plantings in Flats area.
Re-capping of Truck
Stop area.
South of I-90 storm drain
and ICP capping.
Special Area
Management Plan as
prepared by State of
Idaho
East of Theater Bridge
tailings removals and
capping
Remedy is performing adequately.
Channel of SFCDR is expected to
become more stable with time,
Truck portion of RV Park needs
to be re-capped to prevent
direct contact and dispersion of
dust.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-1
Summary of Initial 5-Year Assessment
Activity or Remedial
Remedial Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Central Impoundment
RA
1995 - present
Final closure to be
completed in 2000.
Ongoing monitoring of
CIA seeps.
No assessment at this time; remedy
is only partially complete
None at this time.
Page Pond RA
1997 - present
Majority of RA yet to be
completed: Tailings
removal, placement of
clean fill, modifications
to South and North
Channels, construction
of outlet and discharge
structures to SFCDR,
construction of internal
berms in West Swamp.
No assessment at this time; remedy
is only partially complete
PRP program for baseline and
routine groundwater and
surface water monitoring was
reviewed by EPA and found to
be deficient. PRPs are
required to revise program and
re-submit for EPA and State
review.
Industrial Complex RA
1995-1998
Construction
season 2001
Borrow Area/ICP Landfill
construction.
Ongoing monthly
monitoring of
groundwater wells as
part of observational
approach.
Remedy is performing adequately.
None noted.
Mine Operations Area
RA
1994
None noted:
Remedy is performing adequately.
None noted.
Boulevard RA
1997
None noted.
Remedy is performing adequately.
None noted.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-1
Summary of Initial 5-Year Assessment
Activity or Remedial
Action (RA)
Dates of
Activity or RA
Work Remaining
Assessment
Deficiency of the Activity or
Remedial Action
Railroad Gulch RA
1997
None noted.
Remedy is performing adequately.
None noted.
Central Treatment Plant
RA
1994 - present
Ongoing O&M
Remedy is performing adequately.
None noted.
Bunker Creek
1996- 1997
ICP capping on west
end of Bunker Creek
project area.
Emergency overflow
channel to Gov't Creek.
Remedy is performing adequately.
Protectiveness from direct contact is
not yet achieved until all areas
receive ICP cap.
None noted.
UP Railroad RA
1995-1999
A portion of the UPRR
right-of-way used as a
haul road remains to be
remediated by EPA.
Remedy is performing adequately;
verification sampling indicated that
none of the sampled areas exceeded
1,000 mg/kg lead. 1999 Sampling
Report did indicate that 7 areas
sampled did not have the required
thickness of ICP barrier.
Increasing barrier thickness in
some locations is warranted as
indicated by 1999 sampling.
Milo Creek and Reed
Landing RA
1995-2000
None noted.
Remedy appears to be performing
adequately, however, much of the
remedy has been constructed in last
2 years and will require more time to
determine effectiveness and
protectiveness.
None noted.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-2
Recommendations and Required Actions
Required Action
Party
Responsible
Proposed
Milestone
Date
(quarters
based on
calendar
year)
Oversight
Agency
Potential to Affect
Protectiveness
upon Completion
(X)
Activity
Site-Wide Monitoring Program: Re-confirm that current monitoring
program is gathering appropriate data to address remedy performance
across the Site.
EPA - IDEQ
2nd quarter
2001
EPA - IDEQ
Site-Wide Monitoring Program: Continue monitoring program, report
data results, prepare trend analysis prior to next 5-year review.
IDEQ
Ongoing,
trend report
prior to 2005
EPA
Hillsides Monitoring Program: Continue monitoring program,
conduct trend analyses/reports, conduct annual stakeholder
workshops.
EPA
Ongoing,
trend report in
3rd quarter
2001
IDEQ
Smelter Closure Observation Approach Monitoring: Continue
monitoring program, conduct trend analyses, prepare annual trend
report.
IDEQ:
sampling
EPA: trend
analyses,
reports
Ongoing
Trend report
in 3rd quarter
2001
EPA: sampling
IDEQ: trend
analyses,
reporting
Site-Wide Biological Monitoring: Implement biological monitoring
program for plants and wildlife.
EPA - U.S.
Fish and
Wildlife
2001 -2004
IDEQ
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-2
Recommendations and Required Actions
Required Action
Party
Responsible
Proposed
Milestone
Date
(quarters
based on
calendar
year)
Oversight
Agency
Potential to Affect
Protectiveness
upon Completion
(X)
O&M Plans - Government Funded RAs: Prepare O&M plans
including need for on-going inspections and measures to monitor and
address recontamination potential.
IDEQ
4th quarter
2000-1st
quarter 2001
EPA
O&M Plans - PRP Funded RAs: Review and approve PRP-prepared
O&M plans including need for on-going inspections and measures to
monitor and address recontamination potential.
PRPs
2nd quarter
2001
EPA - IDEQ
ARARs: Conduct an evaluation of new groundwater and surface water
quality criteria or standards and the recently issued TMDL to determine
their status as ARAR or TBCs.
EPA
3rd quarter
2001
IDEQ
X
Future 5-Year Reviews: As remedial activities progress, future 5-year
reviews will include an assessment of the need for any further remedial
actions and the extent of any site recontamination issues.
EPA
By 2005
IDEQ
Remedial Action
Hillsides Performance Standards: Evaluate the need for an ESD or
ROD Amendment to address the adaptive management approach for
establishing hillsides/ performance standards.
EPA
2nd quarter
2001
IDEQ
Smelterville and Wardner Hillslopes: Inspection of catchment wall
areas to determine if additional action is necessary to prevent
recontamination of remediated yards.
IDEQ
Ongoing
EPA
X
Hillsides - Access Control: Assess the need for additional access
control to hillsides and gulches.
EPA
Ongoing
IDEQ
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-2
Recommendations and Required Actions
Required Action
Party
Responsible
Proposed
Milestone
Date
(quarters
based on
calendar
year)
Oversight
Agency
Potential to Affect
Protectiveness
upon Completion
(X)
Gulch Remedial Actions: Conduct yearly surveys to evaluate channel
and surface barrier stability, success of vegetation, and surface water
and groundwater quality
EPA-
USACE
Ongoing
IDEQ
X
Guy Caves Area (Milo Creek): Evaluate the need to cover mine waste
and tailings disposed in Guy Caves with clean material
EPA
3rd quarter
2001
IDEQ
X
Page Pond: Revisions to monitoring approach.
IDEQ
2nd quarter
2001
EPA
Lined Pond: Clean out sediment at bottom of pond.
EPA-
USACE
Construction
season 2001
IDEQ
Smelterville Fiats: Evaluate the need for an ESD or ROD Amendment
to address the increased tailings removal on the Flats and the decision
to defer construction of the groundwater and surface water wetland
trpfltmpnt systems
EPA
2nd quarter
2001
IDEQ
Page Mine Waste Rock Dump: Evaluate the need for additional
efforts to-encourage vegetative growth.
EPA - IDEQ
4th quarter
2000
EPA - IDEQ
X
Central Impoundment Area: Evaluate the need for an ESD or ROD
Amendment to address deferment of construction of a
seep collection system.
EPA
2nd quarter
2001
IDEQ
Union Pacific Railroad: Address barrier thickness deficiencies as
necessary based on 1999 Sampling Report.
UPRR
Construction/
season 2000
IDEQ
X
09/27/00
5-11
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table 5-2
Recommendations and Required Actions
Proposed
Milestone
Date
(quarters
Potential to Affect
based on
Protectiveness
Party
calendar
Oversight
upon Completion
Required Action
Responsible
year)
Agency
(X)
Government Gulch Groundwater and Surface Water: Evaluate the
need for an ESD or ROD Amendment to address groundwater control
and collection systems and creek lining in Government Gulch as
described in the ROD
EPA
2nd quarter
2001
IDEQ
09/27/00
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6.0 Statement of Protectiveness
The remedy being implemented in the Non-Populated Area operable unit of the Bunker Hill
Superfund Site is expected to be protective of human health and the environment upon
completion, provided that the required actions identified in Table 5-2 are implemented.
Although the remedy has not been fully implemented, immediate threats to human health and
the environment have been addressed by source removal efforts, capping activities, erosion
control measures, ongoing treatment of mine water, and institutional controls. These efforts
have reduced or eliminated the potential for humans and animals to have direct contact with
soil/source contaminants, have reduced opportunities for transport of contaminants by surface
water and air, and are expected to provide surface and groundwater quality improvements
over time throughout the site. Groundwater and surface water quality will continue to be
monitored to assess improvements over time. The need for surface and groundwater
collection and treatment measures, as indicated in the ROD, will be evaluated as part of the
second phase of cleanup actions at the site, following the completion of source removal,
capping, and erosion control efforts.
09/26/00
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7.0 Next 5-Year Review
Statutory requirements of CERCLA require ongoing 5-year reviews for Superfund sites once
remediations have been initiated. The next review will be conducted within 5 years of the
completion date of this 5-year review report. The completion date is the date of the signature
shown on the cover of this report. This subsequent review will cover all remedial work,
monitoring, and O&M activities conducted at the Site. This subsequent 5-year report is
expected to summarize more detailed information on protectiveness of the remedy since five
additional years of monitoring data and annual remedy inspection reports will then be
available to judge remedy performance.
09/26/00
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8.0 References
8.1 General Overall References
Amendment to the Record of Decision for the Bunker Hill Mining and Metallurgical
Complex (Non-Populated Areas) Superfund Site, September 3,1996.
Compensation, and Liability Act (CERCLA) Section 121(c), as amended.
Contingency Plan (NCP) Part 300.430(f)(4)(ii) of the Code of Federal Regulations (CFR).
Draft Comprehensive 5-Year Review Guidance (EPA, October 1999).
Explanation of Significant Differences for Revised Remedial Actions at the Bunker Hill
Superfund Site, Shoshone County, Idaho: two separate ESDs, January 1996, April 1998.
U.S. Environmental Protection Agency. Record of Decision, Bunker Hill Mining and
Metallurgical Complex Residential Soils Operable Unit, Shoshone County, Idaho. August
1991.
U.S. Environmental Protection Agency. Record of Decision, Bunker Hill Mining and
Metallurgical Complex, Shoshone County, Idaho. September 1992.
8.2 Site-Specific References
State Superfund Contract and Two Phase Implementation Strategy (Section 3.5)
Idaho Department of Health and Welfare. 1995. State Superfund Contract (SSC) and
Corresponding Documents. May 12,1995.
Bunker Hill Superfund Site 5-Year Review for Populated Areas (Section 4.1.1)
TerraGraphics Inc., March 2000. Draft 1999 Five-Year Review Reports.
Application of the Institutional Controls Program (Section 4.1.3)
McCulley, Frick, & Gilman, Inc., 1999. Bunker Hill Superfund Site 5-Year Review Report,
prepared for the Upstream Mining Group, November 12, 1999.
TerraGraphics, Inc., Final 1999 Five year Review Report, Bunker Hill Superfund Site,
prepared for the Idaho Department of Health and Welfare, Division of Environmental Quality,
April 2000.
Health & Safety Review (Section 4.1.3)
Morrison Knudsen, 1999, Bunker Hill Remedial Action Project Closure Report; Appendix G—
Final Safety Report, February 10, 1999.
Fink, Rich/USCOE, 2000, Health and Safety: telephone interview from Tami
Thomas/CH2M HILL, February 14, 2000.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Operation and Maintenance Manuals (Section 4.1.4.2).
TerraGraphics, 2000. Interim Operations and Maintenance Manual for the Smelterville Flats,
Bunker Hill Site. May 16, 2000.
Surface Water, Groundwater, and Air Monitoring (Section 4.2.1)
CH2M HILL, 1998, Site-Wide Monitoring: Time Series Plots and Initial Evaluation of Data
Quality Trends: memorandum prepared for USEPA, February 10, 1998.
Federal Register. Vol. 62, No. 138, July 18,1999. 50 CFRPart 50, National Ambient Water
Quality Standards for Particulate Matter, Final Rule.
Morrison-Knudsen,1999, Bunker Hill Remedial Action Project Closure Report, February 10,
1999.
TerraGraphics, 1999, DRAFT Bunker Hill Site-Wide Monitoring of Groundwater and Surface
water Trend Analysis: report prepared for Idaho Department of Health and Welfare, Division
of Environmental Quality, Boise, Idaho, August, 1999.
U.S. Environmental Protection Agency, 1990, Bunker Hill SuperfundSite Administrative
Order on Consent: Hillsides Re-vegetation/Stabilization Removal Action: October 1, 1992.
U.S. Environmental Protection Agency. Comprehensive Five-Year Review Guidance. EPA
540R-98-050. OSWER Directive 9355.7-03B-P. Draft, October 1999.
U.S. Environmental Protection Agency. National Recommended Water Quality Criteria
Correction, EPA 822-Z-99-001. April 1999. Office of Water 4304.
U.S. Environmental Protection Agency. Region X. Draft Technical Support Document, Total
Maximum Daily Load for Dissolved Cadmium, Dissolved Lead and Dissolved Zinc in Surface
Waters of the Coeur d'Alene Basin. April 1999.
Hillsides Monitoring Program (Section 4.2.2)
A. Documents
CH2M HILL, 1999, Bunker Hill Hillsides Re-vegetation Conceptual Plan and Monitoring
Plan - Final: report prepared for USEPA, December, 1999.
B. Interviews
White, Tim/CH2M HILL, 2000a, Hillsides Monitoring Program: e-mail interview from
Tami Thomas/CH2M HILL, January 28, 2000.
White, Tim/CH2M HILL, 2000b, Hillsides.Monitoring Program: phone message
interview from Tami Thomas/CH2M HILL, January 31, 2000.
Smelter Closure Observational Approach Monitoring (Section 4.2.3)
A. Documents
CH2M HILL, 1996a, Smelter Area Closure Predesign Report - Bunker Hill Superfund
Site, Kellogg, Idaho: report prepared for USEPA, April, 1996.
CH2M HILL, 1996b, Smelter Closure Area Observational Approach for Seepage
Monitoring: memorandum prepared for USEPA, June 26, 1996.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
B. Interviews
Turner, Alta/CH2M HILL, 2000, Smelter Closure data: e-mail interview from Tami
Thomas/CH2M HILL, February 1, 2000.
Hillsides Remedial Actions (Section 4.3.1)
A. Documents
CH2M HILL, 1999, Bunker Hill Hillsides Revegetation Conceptual Plan and Monitoring
Plan: Work Assignment No. 31-68-0NX9, December 1999.
Dames & Moore, 1990, Bunker Hill Site RI/FS. Vegetation Growing Condition Analysis
Subtask 5.4: Volumes. I and II. Denver, Colorado, May 14,1990.
Dames & Moore, 1990, Bunker Hill Site RI/FS. Revised Technical Memorandum,
Evaluation of Erosion and Effects of Vegetation on Erosion Potential: Denver, Colorado,
May 14,1990.
McCulley, Frick, & Gilman,1992, Bunker Hill Superfund Site Remedial Investigation
Report (RI): Volumes I, II, and III. May 1, 1992.
Panhandle Health District, 1996, Contaminant Management Rules: January 1, 1996.
Panhandle Health District, 1999, Institutional Controls Program Summary.
Pintlar,1992, 1991 Bunker Hill Hillside Project Evaluation Report: January 1992.
TerraGraphics, Final 1999 Five Year Review Report Bunker Hill Superfund Site, prepared
for the Idaho Department of Health and Welfare, Division of Environmental Quality,
April 2000.
U.S. Environmental Protection Agency, 1990, Administrative Order on Consent: Hillsides
Re-vegetation/Stabilization Removal Action: EPA Docket No. 1090-10-01-106, October
3, 1990.
U.S. Environmental Protection Agency, 1996, Memorandum of Agreement between the
U.S. EPA Region X, Hazardous Waste Division and the Idaho Department of Health and
Welfare, Division of Environmental Quality for the Bunker Hill Superfund Site;
Comprehensive Cleanup Plan: March 17,1996.
B. Interviews
Cobb, Jerry /Panhandle Health District, 2000, Applicability oflCP to Hillsides,
Smelterville Flats, Gulches, telephone interview by Tami Thomas/CH2M HILL, January
5, 2000.
Hudson, Bill/CH2M HILL onsite representative for EPA, 1999, Hillsides/Mine waste
dumps status, telephone interview by Tami Thomas/CH2M HILL. December 28, 1999.
Stoupa, Joan/CH2M HILL project manager for Bunker Hill Site under EPA RACS
Contract, 1999, Summary of Actions Performed at Sub-areas: Hillsides, Gulches,
Smelterville Flats, Site-Wide Monitoring, personal interview by Tami Thomas/CH2M
HILL. December 22, 1999.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
White, Tim/CH2M HILL Hillsides Re-vegetation design manager, 1999, Hillsides Re-
vegetation Status, personal interview by Tami Thomas/CH2M HILL, December 30, 1999.
Smelterville Flats Remedial Action (Section 4.3.3)
A. Documents
CH2M HILL, 1996, Bunker Hill Final Smelterville Flats Tailings Removal - Thirty
Percent Design Report: report prepared for USEPA, Bellevue, Washington, December 2,
1996.
CH2MHILL, 1996, Government Gulch Stream - Design Memorandum: memorandum
prepared for USEPA, Bellevue, Washington, July 31,1996.
CH2M HILL, 1996, Bunker Hill Soil Removal Design and Instructions: plans and
instructions prepared for USEPA, Bellevue, Washington, July 1996.
Dames & Moore, 1990, Bunker Hill Site RI/FS; Revised Technical Memorandum,
Evaluation of Erosion and Effects of Vegetation on Erosion Potential: Denver, Colorado,
May 14,1990.
McCulley, Frick, & Gilman, 1992, Bunker Hill Superfund Site Remedial Investigation
Report (RI): Volumes I, II and III, May 1, 1992.
McCulley, Frick, & Gilman, 1996, Bunker Hill Superfund Site Gypsum Pond A-4 Closure
Final Remedial Design Report, April 1996.
Morrison Knudsen,1999, Bunker Hill Remedial Action Project Closure Report, February
10, 1999.
Panhandle Health District, 1996, Contaminant Management Rules, January 1, 1996.
Panhandle Health District, 1999, Institutional Controls Program Summary.
Pintlar,1992, 1991 Bunker Hill Hillside Project Evaluation Report January 1992.
TerraGraphics, 1999, Bunker Hill Small Projects Memorandum: memorandum to IDEQ
and US COE, Kellogg, Idaho, June 30,1999.
TerraGraphics, 1999a, State Lead Activity Update/Summary, Operation and Maintenance
Project Bunker Hill Superfund Site: memorandum, December 23, 1999.
TerraGraphics, 2000, Interim Operation and Maintenance Manual for the Smelterville
Flats, Bunker Hill Superfund Site, prepared for the State of Idaho DEQ and USEPA, May
16, 2000.
U.S. Bureau of Mines, 1998, Bunker Hill Collected Water Wetlands Study: Interagency
Agreement DW14957159-01-0 between the U.S. Environmental Protection Agency and
the U.S. Bureau of Mines, September 14, 1998.
U.S. Environmental Protection Agency, 1990, Administrative Order on Consent:
Hillsides Stabilization and Re-vegetation Work Plan: Submitted to U.S. EPA Superfund
Branch Region X, Seattle, Washington, September 28, 1990.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
U.S. Environmental Protection Agency, 1996, Memorandum of Agreement between the
U.S. EPA Region X, Hazardous Waste Division and the Idaho Department of Health and
Welfare, Division of Environmental Quality for the Bunker Hill Superfund Site;
Comprehensive Cleanup Plan, March 17,1996.
B. Interviews
Bourque, Tom/Terragraphics, 1997, Smelterville Flats, Special Areas Management Plan:
letter report prepared for State of Idaho Department of Environmental Quality, June 12,
1997.
Chavez, Tony/McCulley, Frick & Gilman, 2000, East of Theater Bridge Work, telephone
interview by Tami Thomas/CH2M HILL, January 7, 2000.
Cobb, Jerry /Panhandle Health District, 2000, Applicability oflCP to Hillsides,
Smelterville Flats, Gulches, telephone interview by Tami Thomas/CH2M HILL, January
5, 2000.
Fitzgerald, Mike /TerraGraphics, 2000, CIA seeps, telephone interview by Tami
Thomas/CH2M HILL, February 2, 2000.
Hudson, Bill/CH2M HILL onsite representative for EPA, 1999, East of Theater Bridge
Removals, telephone interview by Tami Thomas/CH2M HILL, January 7, 2000.
Hudson, Bill/CH2M HILL onsite representative for EPA, 1999, Smelterville Flats Work
Remaining, telephone interview by Tami Thomas/CH2M HILL, January 13, 2000.
Hudson, Bill/CH2M HILL onsite representative for EPA, 2000, Gulches and Misc.
Questions: telephone interview by Tami Thomas/CH2M HILL, January 18, 2000.
Mullen, Tom/McCulley, Frick & Gilman, 2000, CIA/A-4 Gypsum pond, telephone
interview by Tami Thomas/CH2M HILL, January 18, 2000.
Reimbold, Mike/CH2M HILL, 2000, A-l Gypsum Pond: telephone interview by Tami
Thomas/CH2M HILL, January 18, 2000.
Stoupa, Joan/CH2M HILL project manager for Bunker Hill site under EPA RACS
contract, 1999, SAMP Questions, telephone interview by Tami Thomas/CH2M HILL,
January 10, 2000.
White, Tim/CH2M HILL soil scientist, 1999, Hillsides Planting Status and Misc.,
December 28, 1999.
Zilka, Nick/IDEQ 2000, Government Gulch Removals: telephone interview by Tami
Thomas/ CH2MHILL, January 18, 2000.
Central Impoundment Area Remedial Action (Section 4.3.4)
A. Documents
CH2M HILL, 1996a, Central Impoundment Area Closure - Thirty Percent Design Report,
Bunker Hill Superfund Site, Kellogg, Idaho: report prepared forUSEPA, Bellevue,
Washington, November 1996.
CH2MHILL, 1996b, Bunker Hill, CIA Seepage Collection Technical Memorandum:
technical memorandum prepared for USEPA, Seattle, Washington, March 20, 1996.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
CH2M HILL, 1997, Central Impoundment Area Closure - Cover Design Technical
Memorandum, Bunker Hill Superfund Site, Kellogg, Idaho: technical memorandum
prepared for USEPA, Seattle, Washington, April 1997.
CH2M HILL, 1998, Bunker Hill, Central Impoundment Stormwater Management:
technical memorandum prepared for USEPA, Seattle, Washington, December 14, 1996.
Morrison Knudsen, 1999, Bunker Hill Remedial Action Project Closure Report, February
10, 1999.
B. Interviews
Cobb, Jerry/Panhandle Health District, 2000, Applicability of ICP to Hillsides,
Smelterville Flats, Gulches, telephone interview by Tami Thomas/CH2M HILL,
January 5, 2000.
Page Pond Remedial Actions (Section 4.3.5)
Audet, D.J., M.R. Snyder and J.K. Campbell. 1999. Biological Monitoring at the Page Pond
Wastewater Treatment Plant Ponds and Wetlands on the Bunker Hill Superfund Site, Idaho,
1997, prepared for EPA IAGNo. DW 14957137-01-0.
CH2M HILL, Inc., 1999. Draft Technical Memorandum. Page Pond Monitoring
Recommendations Bunker Hill Superfund Site. Draft technical memorandum prepared for
USEPA, December 16, 1999.
McCulley, Frick & Gillman, Inc. (MFG), 1994. Bunker Hill Superfund Site. Page Pond
Closure: Draft Final Remedial Design Report. Report prepared for Upstream Mining Group
(UMG), September 1994.
McCulley, Frick & Gillman, Inc. (MFG), 1997. Diversion of Page Pond Wastewater
Treatment Plan Effluent to West Page Swamp. Technical memorandum prepared for the
UMG, June 17,1997.
McCulley, Frick & Gillman, Inc. (MFG), 1999. Bunker Hill Superfund Site. Page Pond
Closure: West Swamp Tailings Removal and Diversion of PPWTP Effluent to West Swamp.
Remedial Action Work Plan. Report prepared for the UMG, April 1999.
Peterson, Scott. Idaho State Department of Environmental Quality. Telephone interview to
obtain construction information regarding the removal and relocation of tailings from the
West Beach area of the West Swamp, January 5, 2000.
Industrial Complex Remedial Action (Section 4.3.6)
CH2M HILL, Inc. 1996. Memorandum. Response to Review Comments to the Smelter Area
Closure Predesign Report prepared for USEPA, July 25,1996.
CH2M HILL, Inc. 1996. PTM Disposal Cell-Conceptual Design prepared for USEPA, May
16, 1996.
CH2M HILL, Inc. 1996. Smelter Area Closure Predesign Report prepared for USEPA, April
1996.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
CH2M HILL, Inc. 1997. Borrow Area Management Plan Final Design (includes Technical
Specifications and Drawings) -100% Submittal prepared for USEPA, April 9, 1997.
CH2M HILL, Inc. 1997. Final Smelter Area Closure Construction Quality Assurance Plan
prepared for USEPA, June 1997.
CH2M HILL, Inc. 1997. Final Smelter Area Closure Final Design Submittal Technical
Specifications and Drawings prepared for USEPA, April 1997.
CH2M HILL, Inc. 2000. Borrow Area Landfill, Management Plan - Phase I, prepared for
USEPA and USACE, May 2000.
OHM Remediation Services Corp. 1995. Final Project Report - Removal of Select Structures
from the Lead Smelter and Zinc Plant at the Bunker Hill Superfund Site prepared for USEPA,
October 1995.
Morrison, Knudsen. 1999. Bunker Hill Remedial Action Project Closure Report prepared for
USEPA, February 10, 1999.
Mine Operations and Boulevard Areas, Railroad Gulch Drainage (Section 4.3.7)
CH2M HILL, Inc. 1994b. Construction Documents for the Mine Operations Area Remedial
Action, prepared for USEPA and BLP, August 1994.
CH2MHILL, Inc. 1996a. Technical Memorandum. Bunker Hill Soil Removal Design and
Instructions, prepared for USEPA and U.S. Army Corps of Engineers. July 15, 1996.
CH2M HILL, Inc. 1996b. Technical Memorandum. ADDENDUM to Bunker Hill Soil
Removal Design and Instructions, prepared for USEPA and U.S. Army Corps of Engineers.
July 26, 1996.
CH2M HILL, Inc. 1996c. Soil Removal Areas Drainage Design - Boulevard and Magnet
Gulch, prepared for USEPA and U.S Army Corps of Engineers. July 31, 1996.
CH2M HILL, Inc. 1997. North End Railroad Gulch Creek Design - Draft No. 2, prepared for
USEPA. June 16, 1997.
Central Treatment Plant (Section 4.3.8)
CH2M HILL, Inc. 1994. Contract Documents for Construction of a Lined Storage Pond,
prepared for USEPA, August 1994.
CH2M HILL, Inc. March 1997. Lined CTP Influent Pond No. 2 and Sludge Pond Facility,
prepared for USEPA, March 1997.
CH2M HILL, Inc. December 1997. CTP High Density Trial Report, Bunker Hill Superfund
Site, prepared for USEPA, December 1997.
CH2MHILL, Inc. January 1997. Technical Memorandum. Failure Modes and Effects
Analysis - Central Treatment Plant, prepared for USEPA, January 7, 1997.
CH2M HILL, Inc. 1996b. Bunker Creek Design, Addendum No. 1, prepared for the USEPA
and USACE. July 12, 1996. (Includes application of ICP barrier at CTP.)
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Bunker Creek (Section 4.3.9)
Spectrum Engineering, 1996. Draft Report. Bunker Creek and Government Gulch Flood
Hydrology, prepared for TerraGraphics and the State of Idaho. March 20, 1996.
CH2M HILL, Inc. 1996a. Bunker Creek Design, prepared for the USEPA and US ACE. July 3,
1996.
CH2M HILL, Inc. 1996b. Bunker Creek Design, Addendum No. 1, prepared for the USEPA
and US ACE. July 12,1996
Union Pacific Railroad Rights-of-Way (Section 4.3.10)
Applied Geotechnology Inc. and USPCI. Study of Lead Contamination Along the Union
Pacific RailroadRight-of-Way. Prepared for the Union Pacific Railroad Company by Applied
Geotechnology Inc. and USPCI, 1991.
McCulley, Friek, and Gilman, Inc. 1997 Annual Remedial Action Implementation Plan for
Remedial Actions Along the Union Pacific Railroad Right-of-Way. Prepared for Union Pacific
Railroad Company by McCulley, Frick, and Gilman, Inc., April 1997.
McCulley, Frick, and Gilman, Inc. Bunker Hill SuperfundSite Union Pacific Area Remedial
Action Work Plan. Prepared for Union Pacific Railroad Company by McCulley, Frick, and
Gilman, Inc., March 1995.
McCulley, Frick, and Gilman, Inc. Letter Report for Submittal of Sampling Results for Union
Pacific Area 5-Yr. Review Rights-of-Way Sampling at the Bunker Hill Superfund Site. Prepared
for Union Pacific Railroad Company by McCulley, Frick, and Gilman, Inc., June 22,1999.
Peterson, Scott. Idaho State Department of Environmental Quality. Telephone interview to
obtain information regarding remediation of areas of the UPRR by the Agencies and
verification sampling and testing. February 2, 2000.
Newly Promulgated or Revised Regulatory Standards (Section 5.1)
American Conference of Governmental Industrial Hygienists. Threshold Limit Values for
Chemical Substances and Physical Agents Biological Exposure Indices. 1999.
U.S. Department of Health and Human Services, Public Health Service, Centers for Disease
Control. "Preventing Lead Poisoning in Young Children." October 1991.
U.S. Environmental Protection Agency. Guidance Concerning Soil Lead Cleanup Levels at
Superfund Sites. OSWER 9355.4-02. September 1989.
U.S. Environmental Protection Agency. Guidance Manual for the Integrated Exposure Uptake
Biokinetic Model for Lead in Children. February 1994. (NTIS #PB93-963510, OSWER
#9285.7-15-1).
U.S. Environmental Protection Agency. Integrated Exposure Uptake Biokinetic Model for
Lead in Children (IEUBK) Version 0.99d (NTIS #PB94-501517, OSWER #9285.7-15-2).
U.S. Environmental Protection Agency. Memorandum Titled: Clarification to the 1994
Revised Interim Soil Lead Guidance for CERCLA Sites and RCRA Corrective Action
Facilities. EPA 540-F-98-030. OSWER 9200.4-27. August 1998.
09/27/00
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
U.S. Environmental Protection Agency. Memorandum Titled: Proposed TSCA 403 Soil Lead
Hazard and OSWER's Lead-in-Soils Policy. EPA 540-F-98-061. OSWER 9200.4-29.
December 1,1998.
U.S. Environmental Protection Agency. Recommendations of the Technical Review Workgroup
for Lead for an Interim Approach to Assessing Risks Associated with Adult Exposures to Lead
in Soil. December 1996.
U.S. Environmental Protection Agency. Revised Interim Soil Lead Guidance for CERCLA
Sites and RCRA Corrective Action Facilities. EPA 540-F-94-043. OSWER 9355.4-12. August
1994.
U.S. Environmental Protection Agency. Technical Support Document for the Integrated
Uptake Biokinetic Model for Lead in Children. December 1994. [NTIS #PB94-963505,
OSWER #9285.7-22]
U.S. Environmental Protection Agency. Validation Strategy for the Integrated Exposure
Uptake Biokinetic Model for Lead in Children. December 1994.
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Appendix A
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Appendix A Identification of Newly
Promulgated or Revised Regulatory Standards
Chemical-Specific Standards
A. Air - Potential Applicable Requirements
Revised
National Ambient Air Quality Standards (40 CFR Part 50) -The health- and welfare-
based standards for particulate matter (measured as PM10, particles that are 10
micrometers in diameter or smaller) enforced at the time of the ROD were promulgated in
1987. They were (1) a 24-hour standard set at 150 micrograms per cubic meter (|ig/m3),
and (2) an annual 24-hour standard set at 50 |ig/m3. Since these PM10 standards were
established, a large number of important new studies have been published on the health
effects of particulate matter. Many of these studies suggest that significant adverse health
effects occur at concentrations below the previous standards. On July 17, 1997, EPA
revised the coarse particulate matter (from particles with diameters less than 10 |im or
PM10 to 2.5 |im or PM2 5) 24-hour standards of 150 |ig/m3to protect against short-term
exposure to coarse fraction particles. The approach now used is thought to provide a more
stable target for control programs and eliminates the need for complex data handling for
missing values. In addition, two new PM2 5 standards were added, set at 15 |ig/m3, based
on the 3-year average of annual arithmetic mean PM2 5 concentrations, and 65 |ig/m3,
based on the 3-year average of the 98th percentile of 24-hour PM2 5 concentrations. EPA
has concluded that fine particles (PM2 5) are better surrogates for those components of
particulate matter most likely linked to mortality and morbidity effects at levels below the
previous standards (PM10 standards).
In 1999, the new standards were challenged in the U.S. Court of Appeals. Until the Court
determines the outcome of the new standards, EPA is supplementing the existing PM10
standard by adding the standard for PM2 5. State and local air agencies are currently
collecting PM2 5 data nationwide. EPA will re-examine this data before designating any
corresponding non-attainment areas. New non-attainment areas are not expected to be
identified before the year 2004.
B. Soil and Dust - Potential To Be Considered Materials
Revised
Center for Disease Control's (CDC) Statement on Childhood Blood Levels (October
1,1991) - In the fourth revision of the Statement on Preventing Lead Poisoning in Young
Children dated October 1, 1991, CDC's Advisory Committee on Childhood Lead
Poisoning Prevention stated that new data indicate significant adverse effects of lead
exposure in children at blood lead levels much lower than previously believed to be safe.
Some adverse health effects have been documented at blood lead levels at least as low as
10 |ig/dL. As a result, the 1985 intervention level of 25 |ig/dL was revised downward to
10 |ig/dL by the CDC in their October 1991 document.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
Revised
Revised U.S. EPA Interim Soil Lead Guidance for CERCLA Sites (OSWER
Directive 9355.4-12, July 14,1994)-The 1994 OSWER directive established OSWER's
approach to addressing lead in soil at CERCLA and Resource Conservation and
Recovery Act (RCRA) sites. It established a streamlined approach for determining
protective levels for lead in soil as follows:
recommends a 400 mg/kg screening level for lead in soil in residential -
properties;
describes how to develop site-specific preliminary remediation goals (PRGs) and
media cleanup standards (MCSs),
describes strategy for management of lead contamination at sites that have
multiple sources of lead.
A previous soil lead OSWER Directive (September 1989) recommended a soil lead
cleanup level of 500-1,000 mg/kg for protection of human health at residential CERCLA
sites (OSWER Directive #9355.4-02). The current recommended residential screening
level for lead of 400 mg/kg is calculated with the Integrated Exposure Uptake Biokinetic
Model (IEUBK) model (Pub #9285.7-15-2, PB93-963511), using default parameters.
EPA recommends that residential PRGs for CERCLA sites can be developed using the
IEUBK model on a site-specific basis, where site data support modification of model
default parameters.
In developing lead PRGs for CERCLA sites, EPA recommends that a soil lead
concentration be determined so that a typical child or group of children exposed to lead
at this level would have an estimated risk of no more than 5 percent of exceeding a
blood lead level of 10 |ig/dL, which corresponds to a soil lead level of 400 mg/kg using
the IEUBK model.
New
Clarification to 1994 Revised Interim Soil Lead Guidance for CERCLA Sites
(OSWER Directive 9200.4-27P, August 1998) -This directive clarified OSWER's 1994
policy on (1) using the IEUBK model and blood lead level studies that were reviewed by
EPA's Science Advisory Board, (2) determining the geographic area to use in evaluating
human exposure to lead contamination, (3) addressing multimedia lead contamination,
and (4) determining appropriate response actions at lead sites. The purpose for clarifying
the existing 1994 directive is to promote national consistency in decision-making at
CERCLA and RCRA lead sites across the country.
C. Groundwater and Surface Water - Potential Applicable Requirements
Withdrawn
Water Quality Standards (40 CFR Part 131.36) - The National Toxics Rule (NTR)
(40 CFR 131.36) sets forth numeric water quality criteria for toxic pollutants for the
protection of human health and aquatic life. In 1992, EPA promulgated NTR federal
requirements for toxic pollutants for the State of Idaho because it failed to fully comply
with Section 303(c)(2)(c) of the Clean Water Act (CWA). Idaho subsequently adopted,
and EPA approved, human health and aquatic life water quality criteria. As a result, in
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
April 2000, EPA withdrew the NTR for the State of Idaho (65 FR No. 71 pages 19659-
19662). Therefore, only State of Idaho Standards, as presented below, are in effect.
New
State of Idaho Water Quality Standards and Wastewater Treatment Requirements
(IDAPA 58.01.02) - The Department of Health and Welfare of the State of Idaho
promulgated rules governing water quality standards in July of 1993. The rules
designated uses that are to be protected in, and of, the waters of the State and established
standards of water quality protection for these uses. In November 1999, the State (Board
of Health & Welfare) adopted significant revisions to the water quality standards. These
revisions were adopted by the 2000 Idaho State Legislature. In 2000, the State Legislature
also elevated the Division of Environmental Quality to Department status. IDEQ the Idaho
Department of Environmental Quality is the state agency responsible for administering
and enforcing the water quality standards.
Because the toxic substance criteria set forth in the National Toxics Rule was incorporated
by reference and adopted in the 2000 Idaho State Water Quality Standards, EPA removed
the State of Idaho from the NTR.
In its current standards, IDEQ has identified 20 water body units that comprise the South
Fork Coeur d'Alene Subbasin (Idaho Administrative Procedure Act (IDAPA)
58.01.02.110.09). Of these, Unit P-6, Government Gulch is located within the Bunker Hill
21-square mile area. Uses identified for Government Gulch include cold water
communities (Cold) and salmonid spawning (SS) for protection of aquatic life and
Secondary Contact Recreation (SCR) for protection of human health. The State's current
surface water use designations for all of the 20 water body units can be found in IDAPA
58.01.02.110.09.
Surface water bodies not specifically designated in the water quality standards and that
fall with the Bunker Hill 21-square mile area include Milo Creek, Bunker Creek and
ancillary tributaries. These units would be classified as undesignated surface waters per
IDAPA 58.01.02.101. The beneficial uses of these water bodies include cold water
aquatic life (Cold), primary or secondary contact recreation (PCR or SCR) (Geoff Harvey,
IDEQ Pers. Comm. 9/26/2000).
In 62 FR 41162, July 31, 1999, EPA designated cold water biota as the beneficial use for
segments of the SFCDR. Idaho's current designation (effective April 2000) for these
segments is secondary contact recreation (SCR). As a result, the State is proposing
changes to its water quality standards to add these designations (Docket 58-0102-0002).
Upon state designation of the uses, EPA is expected to withdraw their designation. The
proposed rulemaking is currently undergoing public comment and is expected to be
approved during the forthcoming (2001) legislative session.
Idaho's current numeric Water Quality Standards for the surface water analytes listed in
the 1992 ROD (antimony, arsenic, beryllium, cadmium, copper, lead, mercury, zinc and
PCBs) are presented in Table A-2.
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BUNKER HILL NON-POPULATED AREAS FIRST 5 YEAR REVIEW
D. Groundwater and Surface Water - Potential Relevant and Appropriate
Requirements
New
State of Idaho Ground Water Quality Rule - Idaho's Ground Water Quality Rule
provides numeric groundwater quality standards for sensitive and general resource
groundwaters of the state (Table II of IDAPA 58.01.11.200.01). The numeric standards for
primary constituents are identical to the federal MCLs under 40 CFR 141. These are
considered potentially relevant and appropriate.
Secondary MCLs (SMCLs) published under 40 CFR 143 regulate contaminants that may
cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as
taste, odor, or color) in drinking water. Idaho's Ground Water Quality rule lists secondary
constituent standards that are identical to the federal SMCLs under 40 CFR 143 (Table 3
of IDAPA 58.01.11.200.01). These are potentially "to be considered" materials (TBCs).
New
National Recommended Water Quality Criteria (FR 63, No. 234, December 7,1998) -
The national recommended water quality criteria developed pursuant to section 304(a) of
the Clean Water Act were published in the Federal Register (December 7,1998; FR Vol.
63 No. 234). The criteria were subsequently republished (April 1999; FR Vol. 64 No. 77).
These criteria are not regulations, and do not impose legally binding requirements on the
states. However, the states are expected to adopt the new or revised numeric water quality
criteria into their standards within 5 years from the date of EPA's publication of these
criteria. For this reason, these criteria are considered as potentially relevant and
appropriate.
E. Groundwater and Surface Water - Potential To Be Considered Materials
New
Total Maximum Daily Load (TMDL) for Dissolved Cadmium, Dissolved Lead, and
Dissolved Zinc in Surface Waters of the Coeur d'Alene Basin (August 2000) - In
September 1996, the U.S. District Court for the Western District of Washington ordered
EPA and the State of Idaho to develop a schedule for completing TMDLs for all streams
identified by the State of Idaho in its 1994 Section 303(d) list. In a letter dated February
26, 1999, the State of Idaho proposed that EPA and the State jointly issue a TMDL for the
Coeur d'Alene Basin. EPA and-the State of Idaho jointly issued the Draft Technical
Support Document (April 1999). It describes the information assembled and analyzed to
develop the TMDL, including applicable water quality standards (freshwater aquatic life
criteria), available water quality and flow data, calculation methods, legal and policy
considerations, and implementation mechanisms. The proposed TMDL would establish
loading capacities, waste load allocations, load allocation, background conditions, and a
margin of safety in accordance with 40 CFR 130.
On August 21, 2000, a TMDL for dissolved cadmium, lead, and zinc in surface waters of
the Coeur d'Alene Basin was jointly released by EPA and the State of Idaho. The TMDL
establishes long-term water quality goals for discrete (e.g., discharging from a pipe) and
non-discrete (e.g., waste piles and floodplain tailings) sources of metals contamination to
the SFCDR. At the current time it is uncertain how the TMDL will be applied at the
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Bunker Hill 21-square mile area. Therefore, EPA is not making a determination at this time
as to the status of the TMDL as an ARAB or TBC. If EPA and DEQ determine that the
protectiveness of the remedy is called into question by the new standards, criteria or limits
identified, any new ARARs or TBCs would be adopted through an appropriate decision
document.
For cadmium, lead and zinc in the dissolved form in the water column, the water quality
criteria designed to protect aquatic life from chronic exposure effects are the-most stringent
criteria that apply to waters in the Coeur dAlene Basin. TMDLs for these metals values are
established based on EPA's 1995 National Toxics Rule. Using an average hardness of 25
mg/L, the chronic criteria for dissolved cadmium, lead, and zinc values are calculated to be
0.38 |ig/L, 0.54 |ig/L and 32 |ig/L respectively. These TMDLs may change if EPA and DEQ
determine that new standards, criteria, or limits are required.
New
Water Quality Standards for Surface Waters of the Coeur d'Alene Tribe (August 30,
2000) - The Coeur d'Alene Tribe has also promulgated water quality standards within its
Reservation waters (which are located downstream of the Bunker Hill 21-square mile area
adjacent to Lake Coeur d'Alene). The Tribe's rule is currently being reviewed by EPA and
has not been finalized (Bill Beckley, Ridolfi Engineers. Pers. Comm. 9/26/2000). The Tribe's
proposed aquatic life criteria are identical to the criteria established in the National Toxics
Rule (NTR) and those adopted by the State of Idaho with the exception of the use of hardness
values. If the hardness value in the water body is below 25 mg/L, the Tribe uses actual
hardness values to calculate hardnessdependent metals criteria instead of using a default value
of 25 mg/L as the state and federal does. The Tribe's human health criteria are identical to the
NTR criteria except that they are calculated based on fish consumption rate of 17.8 grams per
day, which EPA has recommended for recreational users. NTR human health criteria are
based on a fish consumption rate of 6.5 grams per day.
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BUNKER HILL 5-YEAR NON-POP REVIEW (2nd WORKING DRAFT)
Table A-1
Summary of Newly Promulgated or Revised Standards
Media/ Change Status
Category/
Regulation
Entity
Citation
Prerequisite
Requirement
Location
Chemical-Specific Standards
Air
Potentially
Applicable
Requirement
Revised
Clean Air Act National
Ambient Air Quality
Standards (NAAQS)
Federal
42 U.S.C.
Section 7401 et
seq.; 40 CFR
Part 50
Establishes ambient air quality
standards for emissions of
chemicals and particulate
matter.
Emissions that occur during
remedial activities will meet the
current applicable NAAQS including:
Particulate Matter as PM10, (particles
with diameters <=10|j meters): 150
|jg/m3 24-hour average
concentration, 50 |jg/m3 annual
arithmetic mean; Lead at 1.5 jjg
Pb/m3 Quarterly arithmetic mean.
Site-Wide
Soil and Dust
Potential To Be
Considered
Materials
Revised
Advisory
Committee on
Childhood Lead
Poisoning Prevention
Federal
Centers for
Disease
Control's
statement on
Preventing Lead
Poisoning in
Young Children,
1991
Removal of contaminated soils
New data indicate significant
adverse effects of lead exposure in
children at blood lead levels lower
than previous believed to be safe.
The 1985 intervention level of 25
|jg/dL is, therefore, revised
downwards to 10 jjg Pb/dL.
Site-Wide
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BUNKER HILL 5-YEAR NON-POP REVIEW (2nd WORKING DRAFT)
Table A-1
Summary of Newly Promulgated or Revised Standards
Media/ Change Status
Category/
Regulation
Entity
Citation
Prerequisite
Requirement
Location
Chemical-Specific Standards
Air
Potentially
Applicable
Requirement
Revised
Clean Air Act National
Ambient Air Quality
Standards (NAAQS)
Federal
42 U.S.C.
Section 7401 et
seq.; 40 CFR
Part 50
Establishes ambient air quality
standards for emissions of
chemicals and particulate
matter.
Emissions that occur during
remedial activities will meet the
current applicable NAAQS including:
Particulate Matter as PM10, (particles
with diameters <=10|j meters): 150
|jg/m3 24-hour average
concentration, 50 |jg/m3 annual
arithmetic mean; Lead at 1.5 jjg
Pb/m3 Quarterly arithmetic mean.
Site-Wide
Soil and Dust
Potential To Be
Considered
Materials
Revised
Advisory
Committee on
Childhood Lead
Poisoning Prevention
Federal
Centers for
Disease
Control's
statement on
Preventing Lead
Poisoning in
Young Children,
1991
Removal of contaminated soils
New data indicate significant
adverse effects of lead exposure in
children at blood lead levels lower
than previous believed to be safe.
The 1985 intervention level of 25
|jg/dL is, therefore, revised
downwards to 10 jjg Pb/dL.
Site-Wide
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-1
Summary of Newly Promulgated or Revised Standards
Media/
Change Status
Category/
Regulation
Entity
Citation
Prerequisite
Requirement
Location
Groundwater
and Surface
Water
Potential Relevant
and Appropriate
Requirement
New
Ground Water
Quality Rule
State
IDAPA §§58.01.11
Prevent contamination
of groundwater.
Provides for numeric groundwater quality
standards based on protection of human
health and aesthetic qualities.
Site-Wde
New
National
Recommended
Water Quality
Criteria
Federal
FR 63, No. 234,
December 7, 1998.
Criteria were
republished in April
1999.
Applicable to the
waters of the United
States
Recommended water quality criteria for
147 pollutants
Site-Wde
Groundwater
and Surface
Water
Potential To Be
Considered
Materials
New
Total Maximum
Daily Load (TMDL)
for the Coeur
d'Alene Basin
Federal
and
State
Joint
Technical Support
Document, TMDL for
Dissolved Cd, Pb, Zn
in Surface Waters of
the Coeur d'Alene
Basin (August, 2000)
Discharge of lead,
cadmium, and zinc
into the surface waters
of the CDA basin
Establishes total maximum daily load
elements including water quality
standards, loading capacity, natural
background, loads, gross allocations,
waste load allocation, load allocations,
and margin of safety.
Site-Wde
New
Water Quality
Standards
Coeur
d'Alene
Tribe
Draft Water Quality
Standards for
Surface Waters of
the Coeur d'Alene
Tribe (August, 2000)
Discharge of water
into surface waters
within the exterior
boundaries of the
Coeur d'Alene
Reservation
Establishes water quality criteria for
priority pollutants
Site-Wde
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-2
New or Revised Numeric Standards
Media
Regulation
Citation
Analyte
Concentration
Comments
Air
Clean Air Act -
National Ambient Air
Quality Standards
(NAAQS)
40 CFR Part 50
Particulate Matter as
PM10, (particles with
diameters <= 10 |j
meters)
PM2 5 (particles with
diameters <=2.5 |j
meters):
Lead
150 |jg/m3 24-hour average
concentration, 50 |jg/m3 annual
arithmetic mean
65 |jg/m3 24-hour average
concentration, 15 |jg/m3 annual
arithmetic mean
1.5 jjg Pb/m3 Quarterly arithmetic
mean.
PM2 5 standards are not adopted by the site.
Soil and
Dust
Revised U.S. EPA
Interim Soil Lead
Guidance for
CERCLA Sites
OSWER
Directive
#9355.4-12
August 1994
Lead
400 ppm screening level
For a typical child, the 400 ppm soil lead
screening level corresponds to an estimated
risk of no more than 5% exceeding the 10
jjg/dl blood lead level using the IEUBK
model.
Groundwater
Safe Drinking Water
Act - MCLs
40 CFR 141
Arsenic
Copper (at tap)
Lead (at tap)
Mercury
PCBs
Selenium
Silver
Zinc
Nitrate
0.05 mg/L (0.005 mg/L proposed)
1.3 mg/L (Action Level)
0.015 mg/L (Action Level)
0.002 mg/L
0.0005 mg/L
0.05 mg/L
10 mg/L
Drinking Water Standards and Health
Advisories, Summer 2000. Office of Water,
USEPA. EPA 822-B-00-001.
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-2
New or Revised Numeric Standards
Media
Regulation
Citation
Analyte
Concentration
Comments
Groundwater
Safe Drinking Water
40CFR 141
Arsenic
zero
Drinking Water Standards and Health
Act - MCLGs
Copper (at tap)
1.3 mg/L
Advisories, Summer 2000. Office of Water,
USEPA. EPA 822-B-00-001.
Lead (at tap)
zero
Mercury
0.002 mg/L
PCBs
zero
Selenium
0.05 mg/L
Silver
-
Zinc
-
Nitrate
10 mg/L
Groundwater
Idaho Groundwater
IDAPA
Arsenic
0.05 mg/L
Primary and secondary constituent standards
Quality Rule
58.01.11.200
Copper (at tap)
1.3 mg/L
listed.
Lead (at tap)
0.015 mg/L
Mercury
0.002 mg/L
PCBs
0.0005 mg/L
Selenium
0.05
Silver
0.1 mg/L
Zinc
6 mg/L
Nitrate
10 mg/L
10/12/00
A-10
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-2
New or Revised Numeric Standards
Media
Regulation
Citation
Analyte
Concentration
Comments
Surface Water
Idaho Water Quality
Standards - Water
designated for
aquatic life use -
Chronic Freshwater
Criteria
IDAPA
§§58.01.02.210
Antimony
Arsenic
Beryllium
Cadmium*
Copper*
Lead*
Zinc*
Mercury
PCBs
50 jjg/L
1.1 ijg/L
12 |jg/L
3.2 ijg/L
110 jjg/L
0.012 jjg/L
0.014 jjg/L
Idaho water quality standards incorporate toxic
substance criteria set forth in 40 CFR
131.36(b)(1), as of July 1, 1993, with
exception of arsenic which is 50 |jg/L.
Freshwater quality standards and human
health criteria for ingestion of organisms are
incorporated by reference for waters
designated for aquatic life use.
*Freshwater aquatic life criteria for these
metals are a function of hardness and water
effect ratio. Criteria presented are dissolved
metal and correspond to a total hardness of
100 mg/L and a water effect ratio of
1.0. Mercury criterion listed is for total
recoverable.
PCB criterion listed is for individual PCBs.
10/12/00
A-11
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-2
New or Revised Numeric Standards
Media
Regulation
Citation
Analyte
Concentration
Comments
Surface
Water
Idaho Water Quality
Standards - Water
designated for
recreation use -
Human health
criteria for ingestion
of organisms
IDAPA
§§58.01.02.210
Antimony
Arsenic
Beryllium
Cadmium
Copper
Lead
Zinc
Mercury
PCBs
4300 jjg/L
50 jjg/L
0.05 jjg/L
0.000045 jjg/L
Idaho water quality standards incorporate toxic
substance criteria set forth in 40 CFR
131.36(b)(1), as of July 1, 1993, with exception
of arsenic which is 50 |jg/L.
Human health criteria for ingestion of
organisms are incorporated by reference for
waters designated for recreation use.
Water designated for aquatic life use are
incorporated by reference
PCB criterion listed is for individual PCBs.
Surface
Water
National
Recommended
Water Quality
Criteria - Freshwater
Quality Standards,
chronic
FR 63 No. 234,
December 7,
1998 and FR64
No. 77, April 22,
1999
Antimony
Arsenic
Beryllium
Cadmium*
Copper*
Lead*
Zinc*
Mercury
PCBs
50 jjg/L
2.2 ijg/L
9.0 jjg/L
2.5 ijg/L
120 jjg/L
0.77 jjg/L
0.014 jjg/L
Based on National Toxics Rule (last revised April
2000)
*Freshwater aquatic life criteria for these
metals are a function of hardness in the water
column. Criteria presented are dissolved metal
and correspond to a total hardness of 100
mg/L.
Mercury criterion listed is for total recoverable.
10/12/00
A-12
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-2
New or Revised Numeric Standards
Media
Regulation
Citation
Analyte
Concentration
Comments
Surface
Water
National
Recommended
Water Quality
Criteria - Human
health criteria for
consumption of
organisms
FR 63 No. 234,
December 7,
1998 and FR 64
No. 77, April 22,
1999
Antimony
Arsenic
Beryllium
Cadmium
Copper
Lead
Zinc
Mercury
PCBs
4300 jjg/L
0.14 jjg/L
1300 jjg/L
69000 jjg/L
0.051 jjg/L
0.00017 jjg/L
Copper value is not available for consumption
of organisms. Value presented is for
consumption of water and organisms.
PCB criterion listed is for individual PCBs.
Surface
Water
Total Maximum
Daily Load (TMDL)
for the Coeur
d'Alene Basin
Technical
Support
Document,
TMDL for
Dissolved Cd,
Pb, Zn in
Surface Waters
of the Coeur
d'Alene Basin
(August 2000)
Dissolve Cadmium
Dissolved Lead
Dissolved Zinc
0.37 jjg/L
0.54 jjg/L
32 ijg/L
Values established based on EPA's 1995
National Toxics Rule. Freshwater chronic
criterion calculated at hardness of 25 |jg/L.
Surface
Water
Coeur d'Alene Tribe
Water Quality
Standards -
Freshwater Quality
Standards, chronic
Water Quality
Standards for
Siurface Waters
of the Coeur
d'Alene Tribe
(August, 2000)
Antimony
Arsenic
Beryllium
Cadmium*
Copper*
Lead*
190 jjg/L
1.0 |jg/L
11 |jg/L
*Freshwater aquatic life criteria for these
metals are a function of hardness in the water
column. Criteria presented are dissolved metal
and correspond to a total hardness of 100
mg/L.
Mercury criterion listed is for total recoverable.
10/12/00
A-13
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table A-2
New or Revised Numeric Standards
Media
Regulation
Citation
Analyte
Concentration
Comments
Zinc*
Mercury
PCBs
2.5 ijg/L
100 jjg/L
0.012 jjg/L
0.014 jjg/L
Surface
Water
Coeurd'Alene Tribe
Water Quality
Standards - Human
health criteria for
consumption of
organisms
Draft Water
Quality
Standards for
Surface Waters
of the Coeur
d'Alene Tribe
(August, 2000)
Antimony
Arsenic
Beryllium
Cadmium
Copper
Lead
Zinc
Mercury
PCBs
1573 jjg/L
0.051 jjg/L
0.15 jjg/L
0.000016 jjg/L
Tribe's criteria are calculated based on a fish
consumption rate of 17.8 grams per day
instead of 6.5 grams per day as used by NTR.
PCB criterion listed is for individual PCBs.
Notes:
-
|jg/m3
PPm
(jg/L
mg/L
Not available
micrograms per cubic meter
parts per million
micrograms per liter
milligrams per liter
10/12/00
A-14
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Appendix B
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Appendix B
Bunker Hill Hillsides Project Purpose,
Goals, and Objectives
The tables below were excerpted from the Bunker Hill Hillsides Revegetation Conceptual Plan
and Monitoring Plan (CH2M HILL 1999). This information forms the basis for hillsides project
design and long-term monitoring of hillsides treatments. Performance standards listed in Table
B-2 are interim in nature. Monitoring results will be reviewed by the interagency project team
for consistency with project and ROD goals prior to acceptance as final standards.
Table B-1
Bunker Hill Hillsides Project Purpose, Goals, and Objectives
Purpose
Improve the condition and safety of the human and natural environment which have been impaired
by actual or threatened releases of hazardous substances from this site in the Silver Valley, Idaho,
through the implementation of selected response actions for the hillsides.
Goals
1. Improve watershed function by reducing runoff, soil erosion, and transport of pollutants within
and from the site.
2. Establish adapted plant communities capable of natural regeneration and providing ecological
and/or societal values.
Objectives
1. Establish herbaceous cover on sites with less than 50 percent cover with priority to areas with
high contaminant levels and/or sites with less than 25 percent cover.
2. Establish check dams in gullies and on terraces.
3. Establish herbaceous and woody vegetation in gullies and on terraces.
4. Ameliorate soil physical and chemical constraints to watershed function and plant growth.
5. Reduce runoff from terraces.
6. Establish self-regenerating species and, where needed, soil-building species.
7. Minimize colonization by noxious weeds.
8. Manage the Bunker Hill hillsides using adaptive management techniques.
09/27/00
B-1
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table B-2
Bunker Hill Hillsides Project Interim Performance Standards
Interim Performance Standard #1
Herbaceous plant canopy cover of regeneration species shall exceed 50 percent within each planting area
designated in each task order specification within two (2) full growing seasons after installation. Actual
determination of canopy cover will be measured on each 5-acre management unit block. Any management unit
with less than 50 percent cover will be evaluated further to determine the appropriate course-of-action including,
but not limited to, reseeding, addition of soil amendments, lime, or fertilizer, or additional monitoring to determine
rate of cover expansion.
Interim Performance Standard #2
Check dams, built and installed as specified, shall be constructed in all major gullies and adjacent to major gullies
on terraces. Each check dam shall be inspected following precipitation events (including rain, rain-on-snow, and
specific snowmelt events) sufficient to cause sheet erosion runoff from the barren hillsides. The inspection shall
determine if each check dam is retarding or retaining water flow by ensuring that water is not bypassing or "short-
circuiting" each check dam. Any check dam exhibiting short-circuiting of water shall be repaired immediately.
Monitoring shall continue within each gully-check dam system until Objective 3 (as measured by Performance
Standard #3 below) is achieved for that gully.
Interim Performance Standard #3
Vegetation cover of regeneration species shall exceed 70 percent of each major gully bottom and terrace within
two (2) full growing seasons after completion of installation.
Interim Performance Standard #4
4A. Within five (5) years after completion of plant establishment projects, the following ratios of runoff volume
to precipitation shall decrease:
Runoff volume to precipitation (per annual monitoring period)
Hourly runoff volume to hourly rainfall intensity
4B. Water quality of discharges is within Bunker Hill project targets for heavy metals, and turbidity decreases
within five (5) years after completion of plant establishment projects.
Interim Performance Standard #5
Water shall not flow from the terraces into major gullies with sufficient energy to initiate sediment transport and
down-cutting, but shall instead be retained or retarded until it infiltrates, evaporates, or slowly discharges onto the
hillsides. The check dams shall also not result in any terrace being breached due to operation of the check dams.
This shall apply to the vicinity of check dams only and until such time as vegetation becomes established and stops
sediment movement. This would be observed during rain and/or snowmelt events of sufficient intensity to cause
sheet runoff from barren hillsides.
09/27/00
B-2
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BUNKER HILL NON-POPULATED AREAS FIRST 5-YEAR REVIEW
Table B-2
Bunker Hill Hillsides Project Interim Performance Standards
Interim Performance Standard #6
Evidence of regeneration of site species must be present on at least 50 percent of each management unit within 3
years following execution of a given Task Order. Evidence of potential for regeneration includes but is not limited to
one or more of the following:
1. Seed production of onsite plant species and presence of newly germinated seed. The presence of newly
germinated seed must be linked to on-site seed production from existing plant species (either artificially
planted or naturally invading from surrounding areas) to ensure that newly germinated seed did not arise from
previous seeding operations and/or a short-term invasion from offsite species.
2. Expansion of cover by vegetative production of new shoot growth from rhizomes or other underground
structures.
3. Evidence of sprouting from damaged or cut stems of woody species.
Interim Performance Standard #7
1. Comply with State of Idaho Noxious Weed regulations.
Interim Performance Standard #8
1. Use information derived from the Monitoring Program in an iterative fashion to determine the effectiveness,
utility, and validity of each of the performance standards in the project.
09/27/00
B-3
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