ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
This case study is part of a
series focused on ecological
revitalization as part of
contaminated site remediation
and reuse; these case
studies are being compiled
by the U.S. Environmental
Protection Agency (EPA)
Technology Innovation and
Field Services Division
(TIFSD). The purpose of these
case studies is to provide
site managers with ecological
reuse information, including
principles for implementation,
recommendations based
on personal experiences, a
specific point of contact and
a network of sites with an
ecological reuse component.
£EPA
United States
Environmental Protection
Agency
Anaconda Smelter, Anaconda,
Montana, Superfund Case Study
Revitalization of the Upland Areas
This is the story of ecological revitalization in the upland areas of the
Anaconda Smelter Superfund site (the Site), where years of cleanup continue
to transform contaminated lands into functional properties and support a
sustainable environment. Located in southwest Montana, in and near the
towns of Anaconda and Opportunity, the Site is part of the larger Upper Clark
Fork Basin Superfund area. Contamination from nearly 100 years of copper
smelter operations have affected the health and quality of the environment at
the Site. Estimates indicate that more than a billion gallons of groundwater
were contaminated and thousands of acres of soil were affected by fluvially-
transported mine wastes and smelter emissions.
The massive 300-square-mile site area and variable, rugged terrain provided
major remedial design challenges. This case study focuses on the upland areas
of the Site, which include surface soil primarily contaminated by smelter
emissions. Innovative assessment techniques, developed through years of studies
and investigations, helped tailor remediation. Though originally designed for the
Anaconda Smelter Superfund site, these evaluation and remedial processes may
also be applicable at other contaminated sites across the country.
Smelter operations had immediate and long-term effects on the environment.
Very little vegetation was able to survive on nearby properties or areas directly
downwind. Smelting facilities released tons of arsenic, copper, sulfur, lead and
zinc each day. A United States Department of Agriculture Technical Bulletin
stated, "In 1910 and 1911, all of the major tree species were either dead or
dying as far as 5 to 8 miles from the smelter." Local ecosystems worsened
over the years. By the 1980s, forestry impacts were documented as far as 22
miles away. In addition to forests, impacted properties primarily include open
grasslands and individually-owned ranches. These lands need to sustain area
livelihood and local wildlife.
The innovative site evaluation and assessment techniques, paired with
effective remedial processes such as tilling and adding soil amendments, have
helped restore these vital grasslands and ranch areas. The uplands remediation
and ecological revitalization efforts have served to provide key lessons and
replicable assessment techniques for other sites with area-wide contamination.
Ecological
Revitalization
Ecological revitalization is
the process of returning land
from a contaminated state to
one that supports functioning
and sustainable habitat.
Topics Highlighted in
this Case Study:
•	Soil Amendments
•	Use of Native Plants
•	Area-wide Remediation
•	Wildlife Habitat
•	New Evaluation
Techniques
•	Soil Reclamation
March 2016 EPA 542-F-16-001
www. clu-in. ors/ecotools 1

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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Background
The Site is located in the Upper Clark Fork River Basin in
Anaconda Deer Lodge County. During almost 100 years of
operation, the Anaconda smelters and mining at the nearby
Butte site supplied enormous quantities of raw ore for material
production across the country.
The Anaconda Copper Mining Company began large-scale
copper smelting and concentrating activities outside the
town of Anaconda in 1884. In 1902, additional smelting and
processing operations began at a second smelter east of the
town of Anaconda. Butte mining and Anaconda smelting
activities provided most local jobs and revenue in the area; the
industries were the cornerstone of the town and its economy.
The Anaconda smelter had a national reputation as one of
the leading producers of copper and boasted the largest free-
standing smokestack in the world, standing over 580 feet.
In 1977, Atlantic Richfield Company (ARCO) purchased
Anaconda Copper Mining's holdings, which included the
smelting site.
Milling and smelting operations released hazardous waste
into the air and water.
•	Records beginning in 1907 indicate that each day the
smelter released over 30 tons of arsenic, copper, lead,
sulfur and zinc into the environment.
•	By 1978, the daily average of contaminants released
into the surrounding communities and ecosystems had
increased to 578 tons.
•	Because of aerial emissions, contamination spread
across 300 square miles around the Anaconda smelter.
Figure 1: During their years of operation, the Butte
mines and Anaconda smelters produced more than
$300 billion worth of metal.
When the smelter closed in 1980, it left the area's soil and water contaminated with heavy metals from almost
a century of copper smelting. The shutdown quickly devastated the community and investigations revealed the
degree to which the contamination had also damaged local vegetation and aquatic systems, threatening the nearby
blue ribbon trout population.
In 1983, EPA listed this 300-square-mile area as the Anaconda Smelter Superfund site on the Superfund program's
National Priorities List (NPL). Terrain at the Site ranges from steep-slope uplands to level valley floors and
includes a variety of creeks and drainages. The Site is bordered by the Clark Fork River and encompasses the
towns of Anaconda and Opportunity (see Figure 3).
2
Anaconda Smelter, Anaconda, Montana, Superfund Case Study

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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Millions of cubic yards of tailings, furnace
slag and flue dust, and thousands of acres
of soil contaminated by airborne emissions
required remediation.
EPA, ARCO and the Montana Department
of Environmental Quality (MDEQ) have
coordinated cleanup efforts. EPA has
divided the Site into a number of operable
units (OUs). Remedial construction is
ongoing at three OUs, including the
Anaconda Regional Waste Water & Soil
(ARWW&S) OU.
Figure 2: Environmental impacts from the smelter were documented as far
as 22 miles away from the smokestack. Emissions caused short-term and
long-term damage, including limited plant growth and inhibited forestation.
Figure 3: The massive Anaconda Smelter Superfund site includes 20,000 acres impacted by aerial emissions from the smelter.
These areas are called uplands and are shaded in the map above.
Springs-, Warm
| Springs
I Ponds
.1Harm Springs Creek
inaconda3»-
'pportumity
Willow Creek
Anaconda,
O ° 2 4 Mi|es
NORTH I	I	I	I	I
Legend
~ Anaconda Smelter Site Area
Upland Areas
A Anaconda Smelter Smokestack
Sources: Esri, DigitalGlobe, GeoEye, i-cubed. USDA, AEX, Getmapping, Aerogrid, IGN, IGP,
DeLorme, AND, Tele Atlas, First American, UNEP-WCMC, USGS, Mike McLeod, TREC, Inc.,
Butte-Silver Bow Planning Department, and the GIS User Community.
Anaconda Smelter, Anaconda, Montana, Superfund Case Study
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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
The ARWW&S OU covers thousands of acres of land contaminated with arsenic and metals. Fifteen smaller
remedial design units (RDUs) make up the OU, and these contaminated areas can be grouped into three larger
land types, or units.
•	The first land unit of the ARWW&S OU is the area that immediately surrounds the old smelters. Known as
Waste Management Areas and Dedicated Development, this area includes tailings, slag and other smelting
wastes. It also includes railroad bed built out of waste materials and the Anaconda Ponds and Opportunity
Ponds tailings impoundments, in which contamination is about 100 feet deep.
•	The second land unit of ARWW&S OU is the lowland areas. Creeks, streams and rivers contaminated
with sulfidic mine tailings from the Site periodically flooded these lowlands and deposited contamination.
In addition, polluted water used to irrigate lowland areas resulted in soil contamination. Contamination
depth in this section ranges from less than
an inch to several feet in historic stream
channels. Despite metals contamination,
vegetation typically grows in these areas
due to the influence of groundwater and
surface water.
•	Upland areas furthest from the smelter
make up the third land unit; this unit is the
focus of this case study. Airborne smelter
emissions reached soil in these upland
areas and deposited arsenic, metal and
sulphur compounds. Contaminants are
most concentrated in the upper 2 inches of
soil, but low pH and limited soil buffering
capacity may leach copper and zinc up to
18 inches in some areas. Remedial efforts
are taking place on about 20,000 acres
impacted by smelter fallout.
Learning from Site Investigations
Years of investigations and studies shaped cleanup efforts at the Site, and numerous on-site revegetation attempts
informed the final strategies. As early as the 1950s, the Anaconda Copper Mining Company experimented with
revegetating waste piles to abate fugitive dust emissions in the tailings impoundment. The Company also learned
about the utility of amendments in greenhouse studies. In the early 1980s, the Company found that separating new-
plants from wastes using crushed
limestone and clean soil, and
using in-situ soil treatment could
re-establish vegetation. These
results were obtained from two
demonstrations in the 1980s: the
Streambank Tailing Revegetation
Study (STARS) and the
Governor's Demonstration Study
of in-situ treatment of tailings
Anaconda Smelter, Anaconda, Montana, Superfund Case Study
Remedial Design
' Overview Map
Figure 4: Varied topography, as indicated by the different colors
on this aerial map of the Stucky Ridge uplands area, presented
challenges for site remediation. The brown areas required tilling
and chartreuse indicates steep slope reclamation areas.
(Source: EPA and CDM Smith)
During the remedial design phase for soil in the upland areas,
site stakeholders faced a variety of challenges.
•	It was impractical to completely excavate and replace
contaminated soils at such a large site.
•	It was difficult to use large equipment on the steep slopes
of upland areas.
•	Commercial alkaline amendments were expensive.

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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
near the Clark Fork River. STARS also screened
tolerant vegetation and preliminary liming rates
to permanently maintain appropriate soil pH
levels. These studies revegetated treated soils
and wastes rather than using covers composed
of clean off-site soil. This type of revegetation is
more feasible over larger areas than excavation or
surficial stripping.
Lessons learned from those demonstration
studies were used to develop remedial
techniques for the specific conditions at the
Site. This development process was known as
the Anaconda Revegetation Treatability Studies
(ARTS). These studies were conducted in the
early 1990s, and were performed in four phases:
•	Phase I evaluated site-specific experience
with revegetation, worldwide revegetation
literature and current site conditions to
identify limiting factors for growth. This phase identified and sampled candidate plots for revegetation.
•	Phase II included laboratory and greenhouse evaluations of soil treatments, soil amendments and related
species-specific plant responses.
•	Phase III documented five ARTS trial sites - three on tailing material and two on impacted soils.
•	Phase IV presented the investigation results.
From information provided through ARTS, EPA and MDEQ selected in-situ reclamation as the remedy for much
of the ARWW&S OU in a 1998 Record of Decision (ROD). Common in-situ reclamation techniques require some
level of physical soil manipulation, amendment application, and revegetation based on site-specific conditions.
However, large-scale remediation at the Site would require some changes to these common techniques. First, site
stakeholders needed to develop a cost-effective and efficient way to systematically
evaluate remedial needs for the 20,000-acre upland area. As noted in the ROD,
the aim of remedial efforts would be to establish a self-sustaining collection of
plant species to stabilize the soils against erosion and minimize contaminants
reaching soil and groundwater; prevent human contact with contaminants;
maximize water usage; re-establish wildlife habitat; and accelerate successional
processes.
A New Tool: Land Reclamation Evaluation System (LRES)
Because the ARWW&S OU included such a large and varied landscape, it was important to efficiently determine
the conditions of specific areas and appropriate remedies for each area. Site stakeholders needed a method that
was precise and quantifiable and also incorporated non-scientific values, like the history or ownership of the area.
Montana State University's (MSU) Reclamation Research Group, local ecologists and reclamation scientists from
CDM Smith developed a standardized decision-making tool called the Land Reclamation Evaluation System
(LRES) to achieve the ROD's goals.
Common Techniques for Soil Reclamation
Physical methods of soil reclamation can be
divided into ex-situ and in-situ. Ex-situ methods
include transportation of contaminated soil for
cleaning, mechanical separation (using properties
like density) or soil extraction and storage. In-situ
methods can be applied on site, without removal,
such as tilling and amendments. Common in-situ
techniques used in Anaconda include soil mixing
(i.e., tillage) to various depths for contaminant
dilution and the addition of soil organic matter, lime
and other amendments. Very highly contaminated
material is often excavated/removed or a soil cover
is applied. Information on other types of in-situ
treatment can be found at: Safe Management of
Mining Waste and Waste Facilities.
Remedial Team
ARCO, CDM Smith,
EPA, MDEQ, and the
MSU Reclamation
Research Group
Anaconda Smelter, Anaconda, Montana, Superfund Case Study
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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Steep Slope Reclamation
In the ARWW&S OU, some upland areas have slopes too steep for reclamation techniques like
tilling or amendments. PRP contractors developed alternative methods to remediate these areas.
These alternatives vary based on local conditions, such as the slope's steepness and degree of
contamination. Alternatives include:
•	Engineered stormwater controls so runoff
will not contaminate streams.
•	Herbicide aerial application to control
weeds.
•	Organic matter and fertilizer application for
smaller slope areas.
•	Rock check dams to stop erosion.
•	Dozer basins to capture sediments.
•	Grading steep gullies to establish vegetation
at the bottom of gullies.
•	Establishing trees, shrubs and grasses.
Jo one :e< lique as proven successful or the Figure 5: Aerial application of herbicide can help
upland slopes. Investigations and remedial efforts control weeds on steep slopes,
continue to vegetate slope areas and minimize
erosion.
*
The TRES requires:
•	Assessment of potential human and ecological risk.
•	Quantitative scoring of the existing vegetation communities, soil stability attributes and the potential for
contaminant transport.
•	Identification of modifying factors that may impact the level and extent of land remediation.
•	Use of decision diagrams to guide site decision makers in determining remedial actions and levels of
reclamation intensity.
To assess contamination so that remedial techniques could be considered, affected properties were divided
into smaller polygon areas of similar vegetative status. Boundaries for the polygon parcels could be a body of
water, a change in topography or other dividers that were already in place. Each parcel's LRES score included
consideration of vegetation attributes, soil stability attributes and modifying criteria (such as land ownership).
These scores informed decision makers about what to do with each parcel, making the LRES the primary
basis for the remedial design. Parcels were given vegetation scores (0 to 100; these included cover and species
richness) and soil scores (0 to 75; included water erosion and surficial tailings). Parcels with higher scores
were less likely to need remedial action. For example, a parcel with a vegetation score of 73, a soil score of
69 and a total score of 142 was designated as needing no further action. However, a different parcel with a
vegetation score of 7, a soil score of 19 and a total score of 26 needed deep plowing plus soil amendments.
This conceptual design allowed for implementation of the remedial action work plan. Based upon validation-
scoring, it was determined that the long-term compliance standard for the upland areas is a post-remediation
score of 115 or greater.
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Anaconda Smelter, Anaconda, Montana, Superfund Case Study

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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Considering Soil Amendments
In addition to the LRES evaluations and data
collection, other remedial design investigations
were conducted to provide the basis for the in-situ
treatment design. These investigations focused
on surficial soils impacted by smelter emissions.
Many surfaces with low LRES soil scores had
poor buffering capacity due to low pH and high
metal content. Soils with low pH are more acidic
and are likely to allow contaminant mobilization
and leaching into groundwater. Acidic soils can
also inhibit seedling establishment and long-
term plant growth, cause soil infertility, and limit
microbial activity. Soil amendments can reduce
bioavailability of contaminants while enhancing
soil structure and revegetation.
The pre-ROD alkaline amendments considered
were commercial lime, such as limestone and
calcium oxide. These products are expensive
and because the Site is so large, the potentially
responsible party (PRP) hoped to find a more cost-effective alternative. Because the amendments would need to be
applied over a vast area, the 2002 greenhouse studies (during Phase II of the ARTS) by ARCO and MSU assessed
the effectiveness of alkaline industrial byproducts, such as lime kiln dust and cement kiln dust, as replacements for
more expensive commercial products. Though PRP contractors found these byproducts to be effective, they were
also hazardous due to elevated metal levels and high causticity, which could result in health risks during application.
Spent lime was chosen as the appropriate and non-hazardous lime amendment for the uplands. Spent lime is
a byproduct of the beet sugar purification process.1 During sugar beet processing, a precipitate of solid lime
product forms that needs to be discarded, otherwise known as spent lime. Though spent lime is an inexpensive
product, costs related to the transportation are significant as the closest sugar beet refinery is in Billings, Montana.
Nonetheless, site stakeholders selected spent lime as the responsible choice for an alkaline amendment at the Site.
It is effective, less toxic, and even contains some organic matter that further helps plant growth.
Remedial Action
The results of the site-specific evaluations, data collection and demonstrations formed the basis of design for the
contaminated soil remedy in upland areas. The studies:
•	Determined soil tillage would be an effective alternative to soil replacement to achieve metals dilution.
•	Determined organic matter and alkaline amendments would promote plant growth.
•	Found alternatives to expensive and hazardous commercial alkaline amendments.
•	Suggested alternatives for difficult steep-slope reclamations (including planting trees, aerial application of
herbicides, construction of rock check dams and dozer basins).
•	Calculated a new liming equation based on site-specific conditions.
1	https://www.crvstalsugar.com/media/19680/impact.pdf
Updating Application Rates
Studies in the early 1990s calculated a liming equation
(alkaline amendment) based on the specifics of site
contamination. Previous research had developed
an amendment distribution equation based on the
presence of sulfide minerals (often from tailings),
rather than years of constant sulfur dioxide deposition
and resulting depressed pH (from smelter emissions).
Due to years of emissions exposure, the Site's soil
had developed active acidity rather than the potential
for acidity which is due to weathering or leaching
of sulfide minerals. Between 1999 and 2002,
ARCO's demonstration project updated application
rates for active acidity. These updated area-specific
considerations were able to reduce the selected lime
amendment application rate by 25 percent, along with
tests to ensure proper pH levels. Site stakeholders agreed
to use spent lime as the lime amendment at this site.
Anaconda Smelter, Anaconda, Montana, Superfund Case Study
7

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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Upland areas, with the exception of steep-slope areas,
are remediated through a variety of techniques based
on their LRES score. As of 2014, 11,500 acres have
been remediated (8,300 acres remain to be addressed).
Methods included:
•	In-situ soil tillage to dilute metals
concentrations, which is generally limited to
the upper 2 inches of the soil profile, but could
include tilling up to 18 inches.
•	Application of soil amendments.
•	Application of organic matter; top 6 inches should
include at least 1.5 percent organic matter.
•	Application of native seed mixes for
revegetation.
These techniques can be altered for the varied
topography of the upland areas and can allow for
reuse. The ecological risk assessments did not predict
that metal uptake in the revegetated areas would
negatively impact livestock or wildlife consuming the
plants. Site stakeholders have not seen any impacts on
livestock or wildlife from metal uptake2
Steep-slope remedial techniques are still being
investigated and tested.
Development of Seed Mixtures and
Adapted Varieties
Eight seed mixes have been developed for lands being
remediated at the ARWW&S OU. The mixes are
based on the environment to be remediated: general
grassland areas, drainageway/wet areas, bottomlands,
waste management areas, landowner-specific mixtures,
steep slope/dozer basin areas, saline areas, and areas
with particularly high soil metal concentrations.
These mixtures are dominated by wheatgrass, fescue
and poa species that have proven hardy in the semi-
arid climate and soils of Anaconda. These soils have
residual metal contamination, low fertility and damaged
microorganism communities.
2	Potential wildlife bioaccumulation of contaminants
were assessed by Dr. Dale Hoff of EPA in consultation with the
USFWS and Texas Tech University. Their findings indicated
that wildlife risks through direct exposure or through
bioaccumulation were not significant.
Figure 8: The same on-site plot in July 2014
Figure 7: I he same on-site plot with
organic matter applied.
The Role of Organic Matter
Organic matter is especially helpful for
promoting early plant growth. For successful
remediation and revegetation, it was determined
that the top 6 inches of so I should have at
least 1.5 percent organic matter. Remediation
contractors account for existing organic matter
in the soil and use composted manure from
local cattle ranches, making this a green, cost-
effective part of the remedial effort.
8
Anaconda Smelter, Anaconda, Montana, Superfund Case Study

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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Remediation Milestones Timeline
1884-1980: The Anaconda Copper Mining Company conducted copper smelting,
processing and mining activities.
Eariv 1950s: The Anaconda Company used revegetation to abate fugitive dust
emissions.
Earlv 1980s: The Anaconda Company experimented with in-situ remediation of
treated soils and wastes.
1983: EPA listed the Site on the National Priorities List (NPL).
Earlv 1990s: Anaconda Revegetation Treatability Studies (ARTS) were
conducted; these studies informed the Land Reclamation Evaluation System
(LRES), which was developed concurrently.
1998: EPA and MDEQ selected in-situ reclamation as the remedy for the
ARWW&S OU with assessment using LRES.
1999-2002: ARCO's demonstration projects informed decisions on alkaline
amendments.
2003-2009: CDM Smith developed the Vegetation Management Plan to manage
vegetation on reclaimed areas.
2005-2006:	LRES was used to prepare remedial action work plans and designs.
2006-ongoing:	Large scale in-situ soil remediation was performed. Steep slope
reclamation was also conducted.
2010-2014: The Montana NRDP performed remediation on Stucky Ridge (within
the ARWW&S OU) using new varieties of metal-tolerant species.
2010: EPA's Five-Year Review of the Site found that some treated areas remained
poorly vegetated.
2011: CDM Smith conducted a Vegetation Response Investigation to further
study poor plant establishment.
2012: Total Metal Index (TMI) was developed based on the findings of the 2011
investigation.
2013: The Vegetation Management Plan updated to acknowledge different kinds
of land uses and to identify vegetation performance compliance standards.
Anaconda Smelter, Anaconda, Montana, Superfund Case Study
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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Three grass varieties have been developed by the United States Department of Agriculture Natural Resources
Conservation Service from germplasm from smelter-impacted land near Anaconda. These varieties, Copperhead
slender wheatgrass (Elymus trachycaulus), Washoe Great Basin wildrye (Leymus cinereus), and Opportunity big
bluegrass (Poa secunda), were tested on Stucky Ridge (Anaconda) by the Montana Natural Resource Damage Program
(NRDP). NRDP found the grasses performed well. As a result, they are being incorporated into the seed mixtures used
in the upland areas of the ARWW&S OU.
Making Adjustments: Total Metal Index (TMI)
EPA's 2010 Five-Year Review found that some in-situ treated areas remained poorly vegetated. Based on this, the
Five-Year Review recommended further investigations.
•	In 2011, site contractor CDM Smith conducted a Vegetation Response Investigation to further study poor
plant establishment, particularly related to residual metals concentrations.
•	The site team revisited the 2002 greenhouse studies to assess metal impacts on growth during these studies.
•	The 2011 Vegetation Response Investigation found many areas where soil pH was neutral, but remaining
contaminant levels (mainly metals) were negatively impacting plants.
The need to determine an in-situ threshold for residual contamination that would allow for successful vegetation
spurred development of the Total Metal Index (TMI) in 2012. The TMI correlates metal and metalloid
concentrations (either the sum of total arsenic [As], copper [Cu], and zinc [Zn], or only arsenic) with qualitative
plant stress levels. Arsenic is useful as an indicator contaminant both because increases and decreases in arsenic
concentrations were consistent with other combined metal concentrations and because EPA used it at the Site to
determine human health risks for different land uses.
Soil Metal Index (Sum of	Soil Arsenic Index (mg/kg)	General Plant Stress Level
Total As+Cu+Zn in mg/kg*)	Due to Soil Contaminants
700-
166-
Very Low
1,200
245
Low
1,450
290
Low-Moderate
1,700
330
Moderate
2,300
430
Moderate-High
2,900
530
High
3,500+
630+
Very High
*milligrams per kilogram
The TMI is being used to determine if in-situ remediation is
likely to be successful based on the degree of contaminant-
related phytotoxicity. If the post-remediation plant stress
level is likely to be moderate or higher (>1,700 TMI),
then enhanced remediation, such as deeper tillage or more
amendments, needs to be considered. Cleanup techniques
used at high and very high TMI areas include stripping
and removal of the very contaminated surface soil layer,
or applying cover soil and then seeding.
\
Figure 9: Performing soil tiiiing on the Site.
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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
On-site seed mixes are primarily native and
naturalized grasses. Several mixes have
been distributed on the Site depending on
topography (e.g., different species are used
on wetlands versus dry uplands). One plant,
called Redtop, is found throughout the Site
even though it was not in seed mixes. Redtop
is aggressive, grows naturally in the area and
performs well in acidic soils. Seed mixes are
often applied based on landowner preference
and projected future land use.
Land Management
Initial remedial work focused on contaminated areas
owned by the PR P. As work shifted more to private
property, the remedial approach also shifted to better
incorporate private property owners' needs. Many
landowners desired efficient reclamation without long-
term management or property restrictions. As a result,
EPA and ARCO revised the Vegetation Management
Plan in 2013 to acknowledge different kinds of land
uses and allow the cleanup to accommodate individual
landowners' needs, if feasible. Results from the Vegetation
Response Investigation informed development of six
land management categories:
•	Category 1. Unrestricted Use Properties
The soil has less than 250 mg/kg arsenic according to
the TMI, which is the approved level for residential
use. This is primarily used at private properties. No
long-term operation and maintenance is required.
•	Category 2. Upland Properties
The TMI is low to moderate (up to 1,700 mg/kg).
These properties have limited long-term operation
and maintenance responsibilities.
•	Category 3. Upland Properties
The TMI is moderate to high (>1,701 mg/kg).
These areas may have enhanced reclamation and
require future assessments.
•	Category 4. Upland Properties
The TMI is moderate to high (>1,701 mg/kg).
These properties are similar to Category 3 and
require a land management plan.
•	Category 5. High Arsenic Areas
These have restricted uses and more long-term responsibilities; they require a land management plan.
•	Category 6. Waste Management Areas
These have restricted uses and long-term responsibilities.
Depending on the property and desired use, long-term responsibilities can include monitoring and Five-Year
Reviews, and implementing institutional controls to restrict the disturbance of soil. The updated Vegetation
Management Plan for the Site allows for the restoration of private properties faster while supporting future use.
This plan marks the culmination of many different remedial efforts and innovative assessment techniques. EPA
continuously monitors the ARWW&S OU to ensure that the remedial actions continue to be effective and that remedial
action objectives and remedial action goals are being met.
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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Current Land Use
Though remediation continues on much of the Site,
there have been many developments on the site already.
Developers turned 250 acres of the Site into a 21-hole
golf course. Designed by golf legend Jack Nicklaus, the
course combines historic mining artifacts with beautiful
landscaping. Maintenance of the golf course serves the
dual purpose of providing recreation and keeping the Site
vegetated for remedial purposes.
In addition to recreational reuse, the Site also supports
residential and public service developments. Dozens
of homes have been built next to the course, and the
community has plans for a recreational vehicle (RV) park.
Community, Counseling and Correctional Services, Inc.
(CCCS) developed a regional prison facility on remediated property in 2008. AWARE, Inc., a private, non-profit
corporation that provides community-based services to people with mental, emotional and physical needs, also
developed and operates a campus on site. In 2009, a contaminated abandoned railroad bed was removed west of
Anaconda to make way for future highway, sewer and multi-use trail expansion to the West Valley.
There are several commercial companies at the Site. Northwestern Energy began operating an on-site natural
gas-fired electric generation facility, Mill Creek Generating Station, in 2011. U.S. Mineral, an industrial supplier
of coal slag and roofing granules, also operates on a portion of the Site.
Lessons Learned/Next Steps
Remedial action to address site contamination has been implemented at more than 340 residential properties and
more than 11,500 acres of open space. Of the almost 12,000 acres remediated so far, more than 93 percent are
considered successfully reclaimed and thereby protective of human health and the environment. The remaining
areas are being monitored and are anticipated to be successful or will have additional remedial action performed.
Key lessons learned include:
•	Changes in topography required customized remedial techniques. To keep costs low, several techniques
were applied during trials to assess which would have the highest success rates.
•	Cost-effective remedial actions for impacted soils over a large area required a new evaluation tool, LRES,
that was easily replicable and based on quantitative values.
•	Using alternative alkaline amendments can be cost-effective and safe.
•	Evaluating areas with low vegetative success after remediation assisted with long-term solutions and
adjustments to land management plans. It is important to evaluate the amount of metals in the soil, rather
than focusing only on pH.
•	Earlier studies and recently-collected data helped inform the development of compliance standards and
dictate future land management practices.
•	Cooperation between the stakeholders (PRP, county and private landowners) was essential to the ensuring
that remediation would align with future land use goals.
•	Collaboration of oversight agencies, like EPA and MDEQ, allowed efficient development and approval of
innovative techniques to evaluate and remediate impacted lands and to perform long-term land management.
Native Pollinators
Not only do native pollinators provide
us with a significant amount of the food
we eat and contribute to the economy,
they also perform key roles in natural
ecosystems. By helping to keep plant
communities healthy and able to
reproduce naturally, native pollinators
assist plants in providing food and
cover for wildlife, preventing erosion,
and keeping waterways clean. Source:
httD://www. nrcs.usda.gov/lnternet/FSE
D0CUMENTS/nrcsl41n2 014931.ndf
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ECOLOGICAL REVITALIZATION OF CONTAMINATED SITES CASE STUDY
Additional Information
Websites to obtain additional information on the Anaconda Smelter Superfund site and ecological
revitalization include:
EPA Region 8 Site Profile
www2.epa.gov/region8/anaconda-co-smelter
EPA's Eco Tools
www.clu-in org/ecotools/
Mine Tailings Fundamentals: Current Technology and Practice for Mine Tailings Facilities
Operation and Closure Webinar
https://clu-in.org/conf/tio/mining_052015/
ASMR Paper, Land Reclamation Performance Evaluation Process and Standards Used at the
Anaconda Smelter Site, Montana
www.asmr.us/Publications/Conference%20Proceedings/2009/ri29-Rennick-MT.pdf
Frequently Asked Questions About Ecological Revitalization of Superfund Sites
www.clu-in.org/download/remed/542f06002.pdf
Remedial Action, Remedy Performance, and Long-Term Land Management at the Anaconda
Smelter NPL site Webinar
https://clu-in.org/conf/tio/mining2_060415/
The Use of Soil Amendments for Remediation, Revitalization, and Reuse
https://clu-in.org/download/remed/epa-542-r-07-013.pdf
Contact Information
For additional information on the Anaconda Smelter Superfund site, please contact the EPA project
manager:
Charles Coleman
EPA Region 8
(406) 457-5038
coleman.charles@epa.gov
US EPA Region 8 - Montana Operations Office
lOWest 15th St., Suite 3200
Helena, MT 59626
Anaconda Smelter, Anaconda, Montana, Superfund Case Study
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