EPA/DOE
MINE WASTE TECHNOLOGY
PROGRAM
Technology Testing for Tomorrow's Solutions
MINE
.WASTE
TECHNOLOGY
PROGRAM
2OO1 ANNUAL REPORT
EPA DOE Montana Tech Implemented by MSE, Inc.
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EPA/DOE
MINE WASTE TECHNOLOGY
PROGRAM
2001 ANNUAL REPORT
Prepared by:
MSB Technology Applications, Inc.
P.O. Box 4078
Butte, Montana 59702
Mine Waste Technology Program
Interagency Agreement Management Committee
IAG ID NO. DW89938870-01-0
Prepared for:
U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research Laboratory
26 W. Martin Luther King Drive
Cincinnati, Ohio 46268
and
U.S. Department of Energy
National Energy Technology Laboratory
P.O. Box 10940
Pittsburgh, Pennsylvania 15236-0940
Contract No. DE-AC22-96EW96405
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CONTENTS
Page
Vision Statement for the Butte Mine Waste Technology Program 1
Program Manager's Executive Summary 3
Introduction 5
Program Overview 7
Organizational Structure 9
Activities 11
Descriptions, Accomplishments, and Future Direction 11
Activity I Overview—Issues Identification 11
Activity II Overview—Quality Assurance 11
Activity III Overview—Pilot-Scale Demonstrations 12
Project 3 Sulfate-Reducing Bacteria Demonstration 12
Project 8 Underground Mine Source Control 14
Project 12 Sulfate-Reducing Bacteria Reactive Wall Demonstration 16
Project 14 Biological Cover Demonstration 20
Project 15 Tailings Source Control 23
Project 16 Integrated Passive Biological Treatment Process Demonstration 24
Project 16A Sulfate-Reducing Bacteria-Driven Sulfide Precipitation
Demonstration Project 26
Project 19 Site In Situ Mercury Stabilization Technologies 27
Project 21 Integrated Process for Treatment of Berkeley Pit Water 28
Proj ect 22 Phosphate Stabilization of Mine Waste Contaminated Soils 29
Project 23 Revegetation of Mining Waste Using Organic Amendments and Evaluate
the Potential for Creating Attractive Nuisances for Wildlife 29
Project 24 Improvements in Engineered Bioremediation of Acid Mine Drainage 34
Project 25 Passive Arsenic Removal Demonstration Project 35
Project 26 Prevention of Acid Mine Drainage Generation from Open-Pit
Mine Highwalls 37
Project 27 Remediating Soil and Groundwater with Organic Apatite 38
Project 29 Remediation Technology Evaluation at the Gilt Edge Mine 39
Project 30 Acidic/Heavy Metal-Tolerant Plant Cultivars Demonstration, Anaconda
Smelter Superfund Site 42
Project 31 Remote Autonomous Mine Monitor 43
Project 33 Microencapsulation to Prevent Acid Mine Drainage 45
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Project 34 Bioremediation of Pit Lakes (Guilt Edge Mine) 46
Project 35 Biological Prevention of Acid Mine Drainage (Gilt Edge Mine) 49
Project 36 Ceramic Microfiltration System Demonstration 50
Activity IV Overview 52
Project 13 Sulfide Complexes Formed from Mill Tailings Project 52
Project 14 Artificial Neural Networks as an Analysis Tool for Geochemical Data 53
Project 16 Pit Lake System Characterization and Remediation for Berkeley
Pit—Phase III 54
Project 17 Mine Dump Reclamation Using Tickle Grass Project 57
Project 18 Investigation of Natural Wetlands Near Abandoned Mine Sites 57
Project 19 Removing Oxyanions of Arsenic and Selenium from Mine Wastewaters Using
Galvanically Enhanced Cementation Technology 58
Project 20 Algal Bioremediation of Berkeley Pit Water, Phase II 59
Activity V Overview—Technology Transfer 60
Activity VI Overview—Training and Education 60
Financial Summary 62
Completed Activities 63
Key Contacts 64
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VISION STATEMENT
FOR THE BUTTE MINE
WASTE TECHNOLOGY PROGRAM
THE PROBLEM
Mining activities in the United States (not
counting coal) produce between 1 and 2 billion
tons of mine waste annually. These activities
include extraction and beneficiation of metallic
ores, phosphate, uranium, and oil shale. Over
130,000 of these noncoal mines, concentrated
largely in nine western states, are responsible for
polluting over 3,400 miles of streams and over
440,000 acres of land. About seventy of these
sites are on the National Priority List for
Superfund remediation. In the 1985 Report to
Congress on the subject, the total noncoal mine
waste volume was estimated at 50 billion tons,
with 33% being tailings, 17% dump/heap leach
wastes and mine water, and 50% surface and
underground wastes. Since many of the mines
involve sulfide minerals, the production of acid
mine drainage (AMD) is a common problem
from these abandoned mine sites. The cold
temperatures in the higher elevations and heavy
snows frequently prevent winter site access.
The combinations of acidity, heavy metals, and
sediment have severe detrimental environmental
impacts on the delicate ecosystems in the West.
PHILOSOPHY/VISION
End-of-pipe treatment technologies, while
essential for short-term control of environmental
impact from mining operations, are a stopgap
approach for total remediation. Efforts need to
be made on improving the end-of-pipe
technologies to reduce trace elements to low
levels for applications in ultra-sensitive
watersheds and for reliable operation in
unattended, no power situations. The concept of
pollution prevention, emphasizing at-source
control and resource recovery, is the approach of
choice for the long-term solution. Our objective
in the Butte Mine Waste Technology Program is
not to assess the environmental impacts of the
mining activities, but it is to develop and prove
technologies that provide satisfactory short- and
long-term solutions to the remedial problems
facing abandoned mines and the ongoing
compliance problems associated with active
mines, not only in Montana but throughout the
United States.
APPROACH
There are priority areas for research, in the
following order of importance:
Source Controls, Including In Situ
Treatments and Predictive Techniques
It is far more effective to attack the problem at
its source than to attempt to deal with diverse
and dispersed wastes, laden with wide varieties
of metal contaminants. At-source control
technologies, such as sulfate-reducing bacteria;
biocyanide oxidation for heap leach piles;
transport control/pathway interruption
techniques, including infiltration controls,
sealing, grouting, and plugging by
ultramicrobiological systems; and AMD
production prediction techniques should strive
toward providing a permanent solution, which of
course is the most important goal of the
program.
Treatment Technologies
Improvements in short-term end-of-pipe
treatment options are essential for providing
immediate alleviation of some of the severe
environmental problems associated with mining,
and particularly with abandoned ore mines.
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Because immediate solutions may be required,
this area of research is extremely important for
effective environmental protection.
Resource Recovery
In the spirit of pollution prevention, much of the
mining wastes, both AMD (e.g., over 25 billion
gallons of Berkeley Pit water) and the billions of
tons of mining/beneficiation wastes, represent a
potential resource as they contain significant
quantities of heavy metals. While remediating
these wastes, it may be feasible to incorporate
resource recovery options to help offset remedial
costs.
Biofilm Engineering), which can conduct the
more basic type of research related to kinetics,
characterization, and bench-scale tests at
minimal cost to the program, while at the same
time providing environmental education that will
be useful to the region and to the Nation. The
Butte Mine Waste Technology Program supports
cooperative projects between the educational
system and the mining industry, where teams of
students conduct research of mine site-specific
problems, often with monetary support from the
industry. The results are made available to the
industry as a whole and to the academic
community.
THE PARTNERSHIPS
In these days of ever-tightening budgets, it is
important that we leverage our limited funding
with other agencies and with private industry.
The Bureau of Land Management and Forest
Service actively participate by providing sites
for demonstrations of the technologies. It is
important where these technologies have
application to active mining operations to
achieve cost-sharing partnerships with the
mining industry to test the technologies at their
sites. Fortunately, the program has strong
cooperation from industry. Within the U.S.
Environmental Protection Agency, the Butte
program is coordinated and teamed, where
appropriate, with the Superfund Innovative
Technology Evaluation (SITE) program to
leverage the funding and maximize the
effectiveness of both programs. We have strong
interaction, cooperation, and assistance from the
mining teams in the EPA Regional Offices,
especially Regions 7, 8, 9, and 10. Several joint
projects are underway, and more are planned.
A considerable resource and willing partner is
the University system (such as Montana Tech of
the University of Montana, University of
Montana-Missoula, Montana State
University-Bozeman, and the Center for
THE SCIENCE
The research program is peer-reviewed annually
by the Technical Integration Committee (TIC),
who technically reviews all ongoing and
proposed projects. The TIC is composed of
technical experts from the U.S. Environmental
Protection Agency and the cooperating agencies,
academia, environmental stakeholders, and
industry and their consultants.
Roger C. Wilmoth
Chief, Industrial Multimedia Branch
Sustainable Technology Division
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
(MS 445)
26 W. Martin Luther King Drive
Cincinnati, OH 45268
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PROGRAM MANAGER'S
EXECUTIVE SUMMARY
The Mine Waste Technology Program (MWTP)
Annual Report for fiscal 2001 summarizes the
results and accomplishments for the various
activities within the Program. The MWTP has
met its goals by providing assistance to the
public and forming cooperative teams drawn
from government, industry, and private citizens.
The funds expended have returned tangible
results, providing tools for those faced with
mine waste remediation challenges.
After 11 years, everyone involved with the
MWTP can look with pride to the Program's
success. Technology development and basic
research has proceeded successfully through the
efforts of MSB Technology Applications, Inc.
(MSB) and its prime subcontractor Montana
Tech.
MSB has developed thirty-four field-scale
demonstrations, several of which are attracting
attention from the stakeholders involved in the
cleanup of mine wastes.
Montana Tech has developed twenty bench-
scale projects, five of which are ongoing during
2001.
Numerous activities are associated with the
development of a field-scale demonstration.
Among these activities are acquiring federal and
state permits, securing liability limiting access
agreements, developing and adhering to health
and safety operation plans, and complying with
the National Environmental Policy Act and other
federal and state environmental oversight
statutes.
The Program has received substantial support
from state and federal agencies, the mining
industry, environmental organizations, and
numerous associations interested in mining and
development of natural resources at state,
regional, and national levels.
Montana Tech continued the post-graduate
degree program with a mine waste emphasis.
The quality of short courses offered by Montana
Tech is becoming highly recognized among the
mine waste remediation community.
The MWTP recognizes its major
accomplishments and looks forward to providing
new and innovative technologies; meeting the
challenges of mine waste remediation; and
providing economical, permanent solutions to
the nation's mineral waste problems.
Jeff LeFever
MSB MWTP Program Manager
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INTRODUCTION
Mining waste generated by active and inactive
mining production facilities and its impact on
human health and the environment are a growing
problem for Government entities, private
industry, and the general public. The nation's
reported volume of mine waste is immense.
Presently, there are more than sixty mining
impacted sites on the U.S. Environmental
Protection Agency's National Priorities List.
Environmental impacts associated with inactive
and abandoned mines are common to mining
districts around the country, as shown in
Table 1.
Total estimated remediation costs for these
states range from $4 to $45 billion.
Health effects from the predominate
contaminants in mine waste range from mild
irritants to proven human carcinogens, such as
cadmium and arsenic. The large volume of mine
wastes and consequential adverse environmental
and human health effects indicates an urgency
for cleanup of abandoned, inactive, and active
mining facilities. The environmental future of
the United States depends in part on the ability
to deal effectively with mine waste problems of
the past and present, and more importantly, to
prevent mine waste problems in the future.
The fiscal year (FY) 1991 Congressional
Appropriation allocated $3.5 million to establish
a pilot program in Butte, Montana, for
evaluating and testing mine waste treatment
technologies. The Mine Waste Technology
Program (MWTP) received additional
appropriations of $3.5 million in FY91,
$3.3 million in FY94, $5.9 million in FY95,
$2.5 million in FY96, $7.5 million in FY97,
$6.0 million in FY98 and FY99, $4.3 million in
FYOO, and $3.9 million in FY01.
The projects undertaken by this Program focus
on developing and demonstrating innovative
technologies at both the bench- and pilot-scale
that treat wastes to reduce their volume,
mobility, or toxicity. To convey the results of
these demonstrations to the user community, the
mining industry, and regulatory agencies,
MWTP includes provisions for extensive
technology transfer and educational activities.
This report summarizes the progress of the
MWTPinFYOl.
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Table 1. Number and types of sites and abandoned mine lands in Western Region.
State
Alaska
Arizona
California
Colorado
Idaho
Michigan
Montana
Nevada
New Mexico
Oregon
South Dakota
Texas
Utah
Wisconsin
Wyoming
Estimated Number of Sites or Land Areas
10,910 sites
95,000 sites
11,500 sites
20,229 sites covering
26,584 acres
8,500 sites covering
18,465 acres
400-500 sites
19,751 sites covering
11,256 acres
400,000 sites
7,222 sites covering
13,585 acres
3,750 sites
4,775 acres
17,300 acres
14,364 sites covering
12,780 acres
200 acres
5,000 acres
Classification and Estimated Number
mine dumps - 1,000 acres
disturbed land - 27,680 acres
mine openings - 500
hazardous structures - 300
polluted water - 2,002 acres
mine dumps - 40,000 acres
disturbed land - 96,652 acres
mine openings - 80,000
polluted water - 369,920 acres
mine dumps - 171 acres
mine openings - 1,685
polluted water - 830,720 acres
mine dumps - 11,800 acres
disturbed land - 13,486 acres
mine openings - 20,229
hazardous structures - 1,125
polluted water - 84,480 acres
mine dumps - 3,048 acres
disturbed land - 24,495 acres
mine openings - 2,979
hazardous structures - 1,926
Accurate information not available.
polluted water - 715,520 acres
mine dumps - 14,038 acres
disturbed land - 20,862 acres
mine openings - 4,668
hazardous structures - 1,747
Accurate information not available.
polluted water - 44, 160 acres
mine dumps - 6,335 acres
disturbed land - 25,230 acres
mine openings - 13,666
hazardous structures - 658
polluted water - 140,800 acres
mine dumps - 1 80 acres
disturbed land - 61,000 acres
mine openings - 3,750
hazardous structures - 695
Accurate information not available.
Accurate information not available.
polluted water - 53, 120 acres
mine dumps - 2,369 acres
disturbed land - 18,873 acres
mine openings - 14,364
hazardous structures - 224
Accurate information not available.
Accurate information not available.
Information was collected from the following sources and is only an estimate of the acid mine drainage problem in the West.
-Bureau of Land Management -U.S. Department of the Interior
-Bureau of Mines -U.S. Forest Service
-Mineral Policy Center -U.S. Geological Survey
-National Park Service -U.S. General Accounting Office
-U.S. Department of Agriculture -Western Governor's Association Mine Waste Task Force Study
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PROGRAM OVERVIEW
FISCAL 2001 PROGRAM
This Mine Waste Technology Program (MWTP)
annual report covers the period from
October 1, 2000, through September 30, 2001.
This section of the report explains the MWTP
organization and operation.
MISSION
The mission of the MWTP is to provide
engineering solutions to national environmental
issues resulting from the past practices of mining
and smelting metallic ores. In accomplishing
this mission, the MWTP develops and conducts
a program that emphasizes treatment technology
development, testing and evaluation at bench-
and pilot-scale, and an education program that
emphasizes training and technology transfer.
Evaluation of the treatment technologies focuses
on reducing the mobility, toxicity, and volume
of waste; implementability; short- and long-term
effectiveness; protection of human health and
the environment; community acceptance; and
cost reduction.
The statement of work provided in the
Interagency Agreement between the U.S.
Environmental Protection Agency and the U.S.
Department of Energy identifies six activities to
be completed by MWTP. The following
descriptions identify the key features of each and
the organization performing the activity.
ACTIVITY I: ISSUES
IDENTIFICATION
Montana Tech of the University of Montana
(Montana Tech) is documenting mine waste
technical issues and innovative treatment
technologies. These issues and technologies are
then screened and prioritized in volumes related
to a specific mine waste problem. Technical
issues of primary interest are Mobile Toxic
Constituents—Water/Acid Generation; Mobile
Toxic Constituents-Air, Cyanide, Nitrate,
Arsenic, Pyrite, Selenium, and Thallium; and Pit
Lakes. Wasteforms reviewed related to these
issues include point- and nonpoint-source acid
drainage, abandoned mine acid drainage,
streamside tailings, impounded tailings, priority
soils, and heap leach-cyanide/acid tailings. In
addition, under this task Montana Tech produced
a CD-ROM based summary of the Program in
two volumes—Annual Report and Activities in
Depth. The CDs can be obtained from the
personnel listed in the Contacts Section of this
report. The Annual Report data is also available
on the web at www.epa.gov/ORD/NRMRL/
std/mtb.
ACTIVITY II: GENERIC
QUALITY ASSURANCE
PROJECT PLAN
In 2001, EPA approved the Quality Management
Plan for the MWTP. This plan provides specific
instructions for data gathering, analyzing, and
reporting for all MWTP activities.
ACTIVITY III: PILOT-SCALE
DEMONSTRATIONS
Pilot-scale demonstration topics were chosen
after a thorough investigation of the associated
technical issue was performed, the specific
wasteform to be tested was identified, peer
review was conducted, and sound engineering
and cost determination of the demonstration
were formulated.
MSE continued thirteen field-scale
demonstrations during fiscal 2001. One field
demonstration, Selenium Treatment, was
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completed. Ten projects were begun: 1) Passive
Arsenic Removal Demonstration; 2) Prevention
of Acid Mine Drainage Generation from Open-
Pit Mine Highwalls; 3) Remediating Soil and
Groundwater with Organic Apatite; 4)
Remediation Technology Evaluation at the Gilt
Edge Mine; 5) Acidic/Heavy Metal-Tolerant
Plant Cultivars Demonstration, Anaconda
Smelter Superfund Site; 6) Remote Autonomous
Mine Monitor; 7) Microencapsulation to Prevent
Acid Mine Drainage; 8) Bioremediation of Pit
Lakes (Gilt Edge Mine); 9) Biological
Prevention of Acid Mine Drainage (Gilt Edge
Mine); and 10) Ceramic Microfiltration System
Demonstration.
ACTIVITY IV: BENCH-SCALE
EXPERIMENTS
Montana Tech successfully completed three
projects during fiscal 2001: 1) Pit Lake System-
Characterization and Remediation for the
Berkeley Pit; 2) Pit Lake System-Deep Water
Sediments/Pore Water Characterization and
Interactions; and 3) Pit Lake System-Biological
Survey of the Berkeley Pit. Four projects were
begun: 1) an investigation to develop a
technology for removing thallium from mine
waste; 2) sulfide complexes formed from
depositing mill tailings into a pit lake; 3)
artificial neural networks as an analysis tool for
geochemical data; and 4) Pit Lake System
Characterization and Remediation of Berkeley
Pit-Phase III. In addition, Project 11, Pit Lake
System Characterization and Remediation for
Berkeley Pit-Phase II, which assesses the effect
of organic carbon, wall rock/water interactions,
bacteria for natural remediation, and the effect
of redepositing neutral tailings into the Berkeley
Pit was in progress.
ACTIVITY V:
TRANSFER
TECHNOLOGY
MSE is responsible for preparing and
distributing reports for the MWTP. These
include routine weekly, monthly, quarterly, and
annual reports; technical progress reports; and
final reports for all MWTP activities. MSE also
publicizes information developed under MWTP
in local, regional, and national publications.
Other means of information transfer include
public meetings, workshops, and symposiums.
ACTIVITY VI:
PROGRAMS
EDUCATIONAL
Montana Tech has developed a post-graduate
degree program with a mine waste emphasis.
The program contains elements of geophysical,
hydrogeological, environmental, geochemical,
mining and mineral processing, extractive
metallurgical, and biological engineering.
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ORGANIZATIONAL STRUCTURE
MANAGEMENT ROLES AND
RESPONSIBILITIES
Management of the Mine Waste Technology
Program (MWTP) is specified in the Interagency
Agreement. The roles and responsibilities of
each organization represented are described
below. The MWTP organizational chart is
presented in Figure 1.
U.S. ENVIRONMENTAL
PROTECTION AGENCY
The Director of the National Risk Management
Research Laboratory (NRMRL) in Cincinnati,
Ohio, is the principal U.S. Environmental
Protection Agency Office of Research and
Development representative on the Interagency
Agreement Management committee. NRMRL
personnel are responsible for management
oversight of technical direction, quality
assurance, budget, schedule, and scope.
DEPARTMENT OF ENERGY
The Director of the National Energy Technology
Laboratory (NETL) is the principal U.S.
Department of Energy (DOE) representative on
the Interagency Agreement Management
committee. NETL personnel provide contract
oversight for the MWTP. MSE Technology
Applications, Inc. (MSE) is responsible to
NETL for adherence to environmental, safety
and health requirements; regulatory
requirements; National Environmental
Protection Act requirements, and conduct of
operations of all projects.
MSE TECHNOLOGY
APPLICATIONS, INC.
MSE, under contract with DOE, is the principal
performing contractor for MWTP. The MWTP
Program Manager is the point of contact for all
mine waste activities. The Program Manager is
responsible for program management and
coordination, program status reporting, funds
distribution, and communications.
An MSE project manager has been assigned to
each MWTP project and is responsible to the
MWTP Program Manager for overall project
direction, control, and coordination. Each
project manager is responsible for implementing
the project within the approved scope, schedule,
and cost. MSE also provides all staff necessary
for completing Activities III and V and oversight
of Activities II, III, IV, and VI.
MONTANA TECH OF THE
UNIVERSITY OF MONTANA
As a subcontractor to MSE, Montana Tech of
the University of Montana is responsible to the
MWTP Program Manager for all work
performed under Activities I, II, IV, and VI.
The responsibility for overall project direction,
control, and coordination of the work to be
completed by Montana Tech is assigned to the
MWTP Montana Tech Project Manager.
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TECHNICAL INTEGRATION
COMMITTEE
The Technical Integration Committee (TIC)
serves several purposes in the MWTP
organization: 1) TIC reviews new proposals and
ranks them at a meeting held in Butte, Montana;
2) it reviews progress in meeting the goals of the
MWTP and alerts the Interagency Agreement
Management Committee to pertinent technical
concerns; 3) it provides information on the needs
and requirements of the entire mining waste
technology user community; and 4) it assists
with evaluating technology demonstrations as
well as technology transfer. This committee is
comprised of representatives from both the
public and private sectors.
MINE WASTE TECHNOLOGY PROGRAM
ORGANIZATIONAL STRUCTURE
Interagency Agreement | i
Management 1 J
fliteBa/ura TimOppelt | i
1
fiMMbnfemqpenttins 1 * EPA Pro/ect Officer \n \
Jolmmi-M 1 » Roger Wilmoth I |
1
/1/Trte Bishop I
' i
I
1
I
I
1
I
I
1
I
I
1
EPAQuaftjx/tesurance 1 j DOE Project Officer } * i
Officer |_l j Dr. Madhav R. Ghate f*
Lauren Drees J [ J ,
i
i
I
MSE - Creighton Barry 1
Montana Tech - Kari Burgher 1
i
f^ Technical Integration Committee ^
RoryTibbals Golden Sunlight Mine
David Gaskin State of Nevada
Ronald Hill Environmental Consultant
John Ray Montana Environmental
Information Center
Robert Robinson U.S. Department of Interior
Bureau of Land Management
Daryl Reed State of Montana
Thomas Wildeman Colorado School of Mines
John Panta.no BP America, Inc.
John Martin EPA NRMRL
Marshall Leo State of West Virginia
Tom Mdntyre Advanced Silicon Materials
Mike Esishop EPA Region 8
Carol Russell EPA Region 8
Jim Dunn EPA Region 8
Nick Ceto EPA Region 10
1 1
Activity 1 h Activity II \ Activity III | Activity IV 1 /Ict/^rtyV 1 Activity VI |
M7 | MSE | MSE | MT | MSE | MT |
Figure 1. MWTP organizational chart.
10
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ACTIVITIES
DESCRIPTIONS,
ACCOMPLISHMENTS, AND
FUTURE DIRECTION
This section describes the Mine Waste
Technology Program (MWTP) Activities I
through VI and includes project descriptions,
major project accomplishments during fiscal
2001, and future project direction.
ACTIVITY I OVERVIEW ISSUES
IDENTIFICATION
This activity focuses on documenting mine
waste technical issues and identifying innovative
treatment technologies. Issues and technologies
are screened and prioritized in volumes related
to a specific mine waste problem/market.
Following completion of a volume, appendices
are prepared. Each appendix links a candidate
technology with a specific site where such a
technology might be applied. The
technology/site combinations are then screened
and ranked.
Technical Issue Status
The status of the volumes approved for
development includes:
• Volume 1, Mobile Toxic
Constituents—Water and Acid Generation,
complete.
• Volume 2, Mobile Toxic Constituents—Air,
complete.
• Volume 3, Cyanide, complete.
• Volume 4, Nitrate, complete.
• Volume 5, Arsenic, complete.
• Volumes 1-5 Summary Report, complete.
• Volume 6, Pyrite, complete.
• Volume 7, Selenium, complete.
• Volume 8, Thallium, complete.
• Volume 9, Pit Lakes, in progress.
The status of the appendices for approved
projects includes:
• Volume 1, Appendix A (Remote Mine Site),
complete.
• Volume 1, Appendix B (Grouting), complete.
• Volume 1, Appendix C (Sulfate-Reducing
Bacteria), complete.
• Volume 3, Appendix A (Biocyanide),
complete.
• Volume 4, Appendix A (Nitrate), complete.
These documents can be reviewed at the web
site, www.epa.gov/ORD/NRMRL/std/mtb.
ACTIVITY II OVERVIEW
QUALITY ASSURANCE
The objective of this activity is to provide
support to individual MWTP projects by
ensuring all data generated is legally and
technically defensible and that it supports the
achievement of individual project objectives.
The primary means of carrying out this activity
is the Quality Assurance Project Plan, which is
written for each project. This plan specifies the
quality requirements the data must meet, states
11
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the project objectives, describes all sampling and
measurement activities, and contains standard
operating procedures, when applicable. Other
functions of this activity include reviewing
technical systems, validating data, implementing
corrective action, and reporting to project
management.
The U.S. Environmental Protection Agency
approved the MWTP Quality Management Plan
in 2001.
ACTIVITY III OVERVIEW PILOT-
SCALE DEMONSTRATIONS
The objective of this activity is to demonstrate
innovative and practical remedial technologies at
selected waste sites, a key step in proving value
for widespread use and commercialization.
Technologies and sites are selected primarily
from the prioritized lists generated in the
Volumes from Activity I, or they may be a
scale-up from bench-scale experiments
conducted under Activity IV.
ACTIVITY III, PROJECT 3:
SULFATE-REDUCING
BACTERIA DEMONSTRATION
Project Overview
Acid generation typically accompanies sulfide-
related mining activities and is a widespread
problem. Acid is produced chemically, through
pyritic mineral oxidation, and biologically,
through bacterial metabolism. This project
focuses on a source-control technology that has
the potential to significantly retard or prevent
acid generation at affected mining sites.
Biological sulfate reduction is being
demonstrated at an abandoned hard-rock mine
site where acid production is occurring with
associated metal mobility.
Technology Description
For aqueous waste, this biological process is
generally limited to the reduction of dissolved
sulfate to hydrogen sulfide and the concomitant
oxidation of organic nutrients to bicarbonate.
The particular group of bacteria chosen for this
demonstration, sulfate-reducing bacteria (SRB),
require a reducing environment and cannot
tolerate aerobic conditions for extended periods.
These bacteria require a simple organic nutrient.
This technology has the potential to reduce the
contamination of aqueous waste in three ways.
First, dissolved sulfate is reduced to hydrogen
sulfide through metabolic action by the SRB.
Next, the hydrogen sulfide reacts with dissolved
metals forming insoluble metal sulfides.
Finally, the bacterial metabolism of the organic
substrate produces bicarbonate, increasing the
pH of the solution and limiting further metal
dissolution.
At the acid-generating mine site chosen for the
technology demonstration, the Lilly/Orphan Boy
Mine near Elliston, Montana, the aqueous waste
contained in the shaft is being treated by using
the mine as an in situ reactor. A substrate
composed of cow manure, wood chips, and
alfalfa was added to promote growth of the
organisms. This technology will also act as a
source control by slowing or reversing acid
production. Biological sulfate reduction is an
anaerobic process that will reduce the quantity
of dissolved oxygen in the mine water and
increase the pH, thereby, slowing or stopping
acid production.
The shaft of the Lilly/Orphan Boy Mine was
developed to a depth of 250 feet and is flooded
to the 74-foot level. Acid mine water
historically discharged from the portal
associated with this level.
12
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Pilot-scale work at the MSB Technology
Applications, Inc., Testing Facility in Butte,
Montana, was performed in fiscal 1994 prior to
the field demonstration. The objective of these
tests was to determine how well bacterial sulfate
reduction lowers the concentration of metals in
mine water at the shaft temperature (8 °C) and
pH (3).
Status
During fiscal 2001, the field demonstration was
again monitored on a regular basis. Figure 2
presents a cross-section of the mine and
technology installation.
During the past year of monitoring, the data
generally demonstrated a decrease in metals
concentrations (see Figure 3), with the exception
of manganese, which SRBs do not effectively
remove. An increase in metals was observed
during spring runoff as occurred in prior years;
however, the levels decreased when flow rates
returned to normal. Field demonstration
monitoring has been ongoing for 7 years.
Monitoring was scheduled to be completed in
June 2001 but was extended until October 2002.
Figure 2. Cross-section of the Lilly/Orphan Boy Mine and the technology installation.
13
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PORTAL: REMOVAL EFFICIENCIES
LJJ
O 50%
DATE
Figure 3. Metal removal efficiency at the Lilly/Orphan Boy Mine.
ACTIVITY III, PROJECT 8:
UNDERGROUND MINE SOURCE
CONTROL
Project Overview
A significant environmental problem at
abandoned underground mines occurs when the
influx of water contacts sulfide ores and forms
acid and metal-laden mine discharge. The
Underground Mine Source Control Project
demonstrated that grout materials can be used to
reduce and/or eliminate the influx of water into
the underground mine system by forming an
impervious barrier that results in reduced, long-
term environmental impacts of the abandoned
mine.
Technology Description
Groundwater flow is the movement of water
through fractures, fissures, or intergranular
spaces in the earth. Some of the fractures are
naturally occurring; others were the result of
blasting during mining.
For this demonstration, a closed-cell, expandable
polyurethane grout was injected into the fracture
system that intercepts the underground mine
workings. The demonstration consists of three
phases: 1) extensive site characterization; 2)
source control material identification and
testing; and 3) source control material
emplacement.
Phase One, completed in 1999, consisted of
characterization studies, including
hydrogeological, geological, geochemical, and
geophysical information gathering directly
related to the mine and its operational history.
Phase Two encompassed source control material
testing. Approximately 40 materials were tested
according to ASTM methods for acid
resistiveness, shear strength, plasticity,
compressive strength, compatibility, and
viscosity. The source control grout material
selected for injection was Hydro Active Combi
Grout, a closed-celled, expandable polyurethane
grout manufactured by de neef Construction
Chemicals, Inc. When compared to a cement-
based source control material, this material
offered the following advantages: greater
retention of plasticity; less deterioration due to
the acidic conditions and during rock movement;
and better rheological characteristics.
14
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Status
The Miller Mine near Townsend, Montana, was
selected for the demonstration because the
underground workings were accessible, it has a
point-source discharge into the underground
workings, the slightly acidic inflow is laden with
heavy metals, and the inflow could be
potentially controlled using the source control
technology.
Phases One and Two were completed in March
1999. Phase Three, the field emplacement
(shown in Figure 4), was completed in October
1999.
First year monitoring results indicate that the
water flow into the underground mine was
reduced from 10 to 15 gpm to approximately 1
to 1.2 gpm as a result of Phase III field
emplacement.
In April 2000, additional grout was emplaced to
reduce the flow into the mine as low as possible.
The result was a reduction in flow from 1.2 to
.6 gpm.
Figure 4. Grout emplacement in the underground mine workings.
15
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ACTIVITY III, PROJECT 12:
SULFATE-REDUCING
BACTERIA REACTIVE WALL
DEMONSTRATION
Project Overview
Thousands of abandoned mine sites in the
western United States impact the environment
by discharging acid mine drainage (AMD) to
surface water or groundwater. Acid mine
drainage is formed when sulfide-bearing
minerals, particularly pyrite, produce oxygen
and water in a chemical reaction that results in
an increased acidity of the water (lowered pH),
and increased concentration of dissolved metals
and sulfate.
At many abandoned mine sites in the West,
conventional treatment strategies for AMD (e.g.,
lime neutralization) are not feasible because of
the remoteness of the mine locations, insomuch
as a lack of a power source and limited site
accessibility in winter. Sulphate-reducing
bacteria (SRB) are capable of reducing the
sulfate to sulfide, decreasing the load of
dissolved metals in the effluent by precipitating
metals as sulfides, and increasing the pH of the
effluent. To demonstrate the feasibility of using
SRB passive technology for mitigation of AMD
emanating from the toe of a waste rock pile,
three bioreactors were built at the abandoned
Calliope Mine site located near Butte, Montana.
Technology Description
The Calliope mine site includes a collapsed adit
discharging water into a large (66,000 cubic
yards) waste rock pile. This relatively good
quality water flows over the top of the waste
rock and accumulates in a small lower pond at
the toe of the pile. The AMD is mostly
produced by atmospheric water that infiltrates
the waste rock pile and reappears on the surface
at the toe of the pile enriched in metals and with
a pH of 2.6. This AMD also flows to the pond
where it mixes with good quality water and
lowers its pH. A portion of the water that
accumulates in the pond was diverted for
treatment to three engineered SRB bioreactors.
The quantity of AMD that recharges the pond is
related to the amount of atmospheric water that
infiltrates into the waste rock pile. Except for
the first 8 months of operation, atmospheric
precipitation was well below normal.
Consequently, the amount of low pH AMD
laden with metals decreased, and the quality of
water in the pond improved. The pH increased,
and the load of metals decreased, bringing
concentrations of iron (Fe), aluminum (Al), and
manganese (Mn) in the influent AMD below the
target treatment levels for the project.
The SRB bioreactors constructed at the Calliope
abandoned mine site in the fall of 1998 were
approximately 70 feet long, 14 feet wide, and 6
feet high. They were placed in parallel (see
Figure 5) downstream from the pond, allowing
the AMD to be piped to and treated in the
reactors using gravity flow. The bioreactors
were designed to evaluate the SRB technology
applied under different environmental
conditions.
Two bioreactors were placed in trenches. One
was constructed above the ground using a 12-
foot-wide metal half-culvert to investigate the
impact of seasonal freezing and thawing on SRB
activity. To evaluate the efficiency of the SRB
at optimal pH and oxidation-reduction potential
(EH), two of the reactors contained a passive
pretreatment section to increase the alkalinity of
the AMD.
The reactors were designed to flow at a rate of 1
gallon per minute. Bioreactor performance was
monitored monthly by taking pH, EH, dissolved
oxygen, and temperature measurements, and
collecting samples of influent and effluent for
chemical analysis. The analytes included SRB
population; pH; EH; dissolved oxygen;
alkalinity; and concentrations of sulfate, sulfide,
16
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dissolved metals, aluminum (Al), arsenic (As),
cadmium (Cd), copper (Cu), iron (Fe),
manganese (Mn), and zinc (Zn).
Each bioreactor was filled with a combination of
organic matter and cobbles placed in discrete
chambers (see Figures 5 and 6). Reactors II and
IV also have a crushed limestone chamber.
Each of these media was expected to play a
certain role in the treatment train. 1) The
organic matter, an electron donor and carbon
source for the SRB, was provided as an 80% to
20% by volume mixture of cow manure and cut
straw. The cow manure was also the SRB
source. The cut straw was added to provide
secondary porosity to the mix and to prevent
settling of the medium. 2) For the pretreatment
section, a chamber with cow manure was
included to lower the EH of AMD. 3) Crushed
limestone provided the buffering capacity to
increase the pH of AMD in the pretreatment
section. 4) Cobbles placed in the reactive,
primary treatment section of the bioreactor were
supposed to provide stable substrate for bacterial
growth.
Chambers filled with organic carbon or
limestone were each 5 feet long; whereas,
chambers filled with cobbles were 50 feet long.
Such dimensions were selected based on the
literature review and information acquired
through the bench-scale test that was conducted
in the MSE Technology Applications, Inc.,
laboratory in 1998. Preliminary results of the
bench-scale test, at the time of the bioreactor's
design, indicated the required residence time in
the reactors should range from 3 to 5 days. This
resulted in the bioreactors being sized for a flow
rate of 1 gallon per minute. To provide
flexibility, the flow and hydraulic head control
systems placed in the bioreactors ensure a much
wider range of the residence time.
The main challenges were to design the organic
carbon chambers so the AMD would permeate
through the entire cross-sectional area without
channeling and to ensure that the organic
substrate did not settle. These goals were
achieved by placing the organic substrate in the
cellular containment system (CCS) (U.S. Patent
No. 6,325,923) consisting of 10 lifts of
TerraCell™ (see geogrid in Figure 6) that would
limit settling of the organic matter to each
individual cell if it occurred. The TerraCell™
material, commonly used in landscaping for
slope stabilization and made of high density
polyethylene, was used to form CCS to house
the organic matter. The CCS prevented the
organic matter from settling to the bottom of the
bioreactor, thus, fostering the flow of AMD
through the entire cross-sectional area without
channeling. Each layer (lift) of TerraCell™ was
positioned at 60 degrees off the horizontal plane
so that the cells of each lift would be partially
offset with respect to the cells of adjacent lifts.
Each lift was 6 inches thick (as measured along
the horizontal direction of flow) and contained
11-inch by 8.5-inch rhombohedral-shaped cells.
Status
The bioreactors operated from December 1998
to July 2001, when they were decommissioned.
The decommissioning activity included an
autopsy of the solid matrix material that was not
accessible during the operational time. Autopsy
sampling included collecting solid matrix
samples for chemical analyses to determine
concentrations of total metals (Al, As, Cd, Ca,
Cu, Fe, Mg, Mn, and Zn), sulfate, sulfide,
nitrogen, phosphorous, and total organic carbon
(TOC) in the chambers of organic matter and
limestone. Bacteriological analyses were also
conducted to determine SRB population in the
organic substrate and in the limestone. Because
the cobbles did not have a visually discernible
film of bacteria or chemical precipitate, no solid
matrix samples were collected from these
chambers.
Aqueous samples were also collected from the
previously inaccessible bottom of the crushed
limestone and cobble chambers and analyzed for
total and dissolved metals.
The autopsy revealed a convoluted biochemical
environment that was probably caused by the
dramatic change in the AMD chemistry after the
first 10 months of operation. The material
17
-------
examined during the autopsy showed the mixed
results of processes that were occurring at low
pH and a reasonably high load of metals with the
subsequent reactions that were characteristic for
water of neutral pH laden with much less of the
dissolved metals.
Interpretation of monthly monitoring results
combined with the autopsy findings allowed for
the formulation of a number of conclusions and
recommendations, the most essential of which
are listed below.
• The CCS worked very well in preventing
settling of the organic matter and ensuring
uniform flow of AMD throughout the entire
cross section of the organic carbon with no
preferential flow paths (channeling).
• Configuring the bioreactors to accommodate
flow in a horizontal plane (rather than in the
vertical direction) was successful. Problems
that were experienced with reductions in flow
rate turned out to be associated with the
AMD distribution system that was plugged
by iron and aluminum hydroxide precipitates.
This hindrance, however, is common to both
configurations.
• The SRB establishment in the bioreactors
took time. Once established and supplied
with organic matter, they maintained a
population of E+4 most probable
number (MPN)/milliliter or higher in the
aqueous phase at temperatures ranging from
2 to 16 °C.
• The SRB average population of 2.06E+6
MPN/cubic centimeter in the solid matrix of
organic matter was two orders of magnitude
greater than the SRB population present in
the aqueous phase.
• The AMD in the bioreactors was notably
stratified with respect to oxidation-reduction
potential that was up to 400 millivolts lower
at the bottom of the bioreactors than at the
top. Because maintaining reduced conditions
is required for SRB, the bioreactors should
have been more carefully isolated from
atmospheric air. A plastic liner placed on top
of the bioreactors is preferred over the straw
bails used for this project.
• Only Zn, Cu, and Cd were being removed as
sulfides due to SRB activities. Changes in
concentrations of other metals (Fe, Mn, Al,
and As), which do not necessarily precipitate
as sulfide, seemed to be affected by SRB
only in an indirect manner by responding to
increased pH caused by SRB activity.
• For the Calliope site climatic and
hydrochemical conditions, the thresholds for
removing Zn, Cd, and Cu were
approximately 500 micrograms per liter
(|ig/L), 5 (ig/L, and 80 (ig/L, respectively.
These thresholds were slightly lower for
Bioreactors II and IV than for Bioreactor III,
which did not include a pretreatment cell.
This indicates that the removal thresholds
were dependent on the configuration of the
bioreactor but were not affected by the
shutdown and freezing of a bioreactor during
winter.
• Most of the metal sulfides that were formed
due to the SRB activity precipitated within
the organic matter. The same seems to be
true for the rest of the metals that must have
formed hydroxides and carbonate
compounds. The role of the cobble chamber
was limited to a collection sump for a small
mass of precipitates that escaped the organic
matter chambers. This demonstrated that
there was no need for the large cobble
chamber, which could have been substituted
with a smaller "trap" sump.
• The abundance of TOC present (20% by
weight) in the organic matter chamber at the
end of the project demonstrated that the
bioreactors would have worked equally
efficiently with a much smaller supply of
organic carbon, provided the same residence
time of AMD was maintained. Since the
organic matter mass inhibits permeability, it
is prudent to reduce the ratio of organic
18
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carbon to the permeability enhancing
component (e.g., gravel, shell, etc.) and have
more permeable medium.
• Since most of the material that caused
plugging was found within and adjacent to
the outlets of the AMD distribution system,
there is a need to devise a system that would
allow for occasional breakdown and removal
of that material. Such a system might
involve only a few outlets rather than the
three dozen used in this design. It may
include ports extended to the ground surface
that would facilitate blowing in combustion
engine exhaust to destroy plugging material
that would then be removed by bailing.
Overall, the project documented that SRB
technology, as applied in this demonstration, is
effective in removing Zn, Cu, and Cd by
precipitating them as sulfides. Removal
mechanisms for Fe, Al, Mn, and As were
overshadowed by a dramatic change of the
quality of the influent AMD. The results of the
project have also allowed the formulation of an
important recommendation regarding the design
and construction of SRB bioreactors.
Organic
Carbon
CrushedLimestone
Organic
Carbon
Cobble
Pretreatment
Section
Lower
Pond,
Source
of AMD
AMD
Discharge
Piping
Above
Ground
Reactor
-Below
Ground
Reactors
Figure 5. Layout of bioreactors.
19
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Treated
AMD
Discharge
Longitudinal Cross-Section of a Bioreactor
-14'
AMDSupplyX \
Distribution System-^
Terracell™ filled
Mix of Manure (80%)
and Cut Straw (20%)
2x4 Geogrid Hangers
-m
Terracell"
\
Geotextile (woven) 40M|IThk.
Geomembrane 40 Mil Thk.
Geotextile (woven) 40 Mil Thk.
Cross-Section of the Organic Carbon Supply Chamber in Below Ground Bioreactor
Figure 6. Bioreactors design.
ACTIVITY III, PROJECT 14:
BIOLOGICAL COVER
DEMONSTRATION
Project Overview
Acidic, metal-laden waters draining from
abandoned mines have a significant
environmental impact on surface and
groundwater throughout the nation and the
world. Specifically, the State of Montana has
identified more than 20,000 abandoned mine
sites, on both public and private lands, resulting
in more than 1,300 miles of streams
experiencing pollution problems.
Acid mine drainage arises from tailings and
waste rock containing sulfide minerals and
lacking acid-consuming carbonate minerals.
Sulfide minerals, such as pyrite (FeS2), are
oxidized to form sulfate when water containing
oxygen infiltrates tailings and waste rock. This
process can be described by the following
reaction:
4FeS2 +1502 +2H20 -> 4Fe3+ + 8SO42' +4H
(1)
The activity of bacteria, such as Thiobacillus
ferrooxidans, which are capable of oxidizing
inorganic sulfur compounds, greatly accelerates
this reaction. The ferric iron (Fe3+) produced in
the above reaction also contributes to pyrite
oxidation:
FeS2 +14Fe3+ + 8H2O -> 15Fe2+ + 2SO42' + 16H+. (2)
T. ferrooxidans is also capable of oxidizing
ferrous iron (Fe2+) produced in the above
reaction:
4Fe2+ + O2 + 4H+ -> 4Fe3+ + 2H2O. (3)
Although the above reaction consumes some
acidity, the ferric iron produced is capable of
oxidizing more pyrite and producing much more
acidity (via reaction 2).
The key to breaking this cycle is preventing the
initial oxidation of pyrite. Bound with iron, the
sulfur in pyrite is unable to participate in the
microbially catalyzed reactions that cause acid
generation. Preventing oxygen infiltration into
tailings and waste rock is necessary to prevent
oxidation of pyrite and subsequent acid
generation. An innovative method to prevent
oxygen transport into tailings is constructing and
20
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maintaining a biologically active barrier on the
surface of the tailings. This barrier is made up
of microorganisms that consume dissolved
oxygen from the infiltrating water, thereby,
maintaining the reducing conditions necessary
for pyrite to remain bound in mineral form.
MSB Technology Applications, Inc. and
researchers at the Center for Biofilm
Engineering at Montana State University are
investigating the microbial processes involved
with establishing and maintaining subsurface
and near surface microbial barriers for hydraulic
control and microbially catalyzed reactions.
Biofilm barrier technology has been successfully
tested in laboratory and field-scale systems
where permeability reductions of five orders of
magnitude were achieved. During these tests, it
was also shown that biofilm barriers can
successfully remove oxygen from infiltrating
waters to trace levels.
By conducting this demonstration, the Mine
Waste Technology Program is illustrating the
ability of microbial biomass to reduce the
permeability of mine tailings and remove
oxygen from infiltrating water, thereby, reducing
the generation of acid mine drainage. This
technology promises to be a cost-effective
approach for stabilizing and remediating acid-
generating abandoned mine tailings.
Technology Description
A biologically active zone is established in the
tailings by adding a nutrient solution to the
surface of the tailings pile. The nutrient solution
contains low cost ingredients that serve as
sources of carbon and energy for microbial
growth, as well as sources of nitrogen,
phosphorous, and necessary micronutrients. The
nutrient solution is formulated to stimulate
indigenous oxygen-consuming microorganisms,
as well as sulfate-reducing bacteria (SRB). In
some cases, a microbial inoculum containing
appropriate microorganisms may have to be
added. The oxidation of carbon compounds in
the nutrient mixture by microorganisms depletes
oxygen from infiltrating water. Also, bacterial
cells and associated extra-cellular polymers
occupy free pore space within the tailings
matrix, greatly reducing permeability. The
reduction of water volume flowing through the
tailings and depletion of oxygen as water passes
through the barrier will mitigate pyrite oxidation
and subsequent acid generation. The anaerobic
conditions and production of organic acids by
fermentative bacteria will also promote SRB
growth. The SRB activity is desirable because it
neutralizes acid and stabilizes metals by H2S-
mediated metal sulfide precipitation. After
establishing the biological barrier, periodic
nutrient treatments are applied to maintain the
barrier.
Status
The site selected for implementing this
technology is the Mammoth tailings site located
in the South Boulder Mining District
approximately 18 miles from Cardwell,
Montana. Two lined test cells were constructed
at the field site in the fall of 1999. An initial
nutrient treatment was applied to one of the test
cells (treated cell) in the fall of 1999 (see
Figure 7). Additional nutrient treatments were
applied to the treatment cell in the spring and
summer of 2000 and 2001. The control
(untreated) cell received an equivalent amount
of water to that applied to the treatment cell
during nutrient treatments. Other than the
nutrient or water treatments, all water entering
the test cells was due to natural precipitation.
The test cells were not operated during the
winter months when they were frozen.
The nutrient formulation used for the initial
treatment and treatments applied in 2000
included molasses as a carbon and energy
source, urea as a source of nitrogen, and
potassium phosphate. Drainage from the treated
cell had a slightly higher pH than drainage from
21
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the untreated control cell. The mean dissolved
metal concentration in effluent from the treated
cell relative to the control cell was 76% lower
for aluminum, 90% lower for copper, and 38%
lower for zinc. Drainage from the control cell
exceeded the maximum contaminant level
(SMCL) for copper (1.0 mg/L), while the copper
concentration in drainage from the treated cell
remained below the SMCL. These results
indicate the molasses-based treatment improved
the water quality of drainage from the tailings at
the mammoth site.
Laboratory column tests conducted in the winter
of 2000-2001 indicated whey-based nutrient
treatments were superior to molasses-based
treatments for preventing acid mine drainage
generation. The effect of molasses treatments,
as determined by increased drainage pH, lasted
1-2 months; whereas, whey treatments
influenced effluent pH for approximately 6
months. Whey-based nutrient solutions were
applied to the treatment cell during the spring
and summer of 2001.
Whey is a byproduct of cheese manufacturing
that contains organic carbon primarily in the
form of lactose and protein. The results of the
whey treatments in the field test were similar to
those observed for the molasses-based
treatments with a slightly higher pH and lower
concentrations of dissolved aluminum, copper,
and zinc in drainage from the treated cell
relative to the control cell. Thus, the increased
effectiveness of whey-based treatments over
molasses-based treatments observed in the
laboratory experiments was not apparent in the
field test. This is likely the result of the much
higher dosages of the whey in the nutrient
solutions used to treat tailings in the laboratory
experiments. Further research is needed to
optimize the dosage rates and composition of
nutrient solutions, although these parameters are
likely dependant on properties of the specific
tailings to be treated. Overall, the results
indicate that this is a promising technology for
source control of acid mine drainage.
Figure 7. Application of nutrient solution to the test cells at the Mammoth site.
22
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ACTIVITY III, PROJECT 15:
TAILINGS SOURCE CONTROL
Project Overview
Processing metallic ores to extract the valuable
minerals leaves remnant material behind called
tailings. In the case of sulfide mineral-bearing
ores, process tailings often contain large
quantities of sulfide minerals that do not meet
the economic criteria for extraction. These
remnant sulfide minerals are usually pyrites and
nonextracted ore minerals. The exposure of
these minerals to air and water often leads to
detrimental environmental conditions such as
increased sedimentation in surface waters due to
runoff events, increased wind borne particulate
transport, generation of acid mine drainage, and
increased metals loading in surface and
groundwaters.
Technology Description
The objective of this demonstration was to
identify potential source control materials and
apply one or more of them at a selected site.
The demonstration consists of two phases: 1)
site characterization and materials testing; and 2)
materials emplacement and long-term
monitoring and evaluation.
Phase one consisted of the site characterization
studies, including hydrogeological, geological,
and geochemical information directly related to
the tailings impoundment. The materials testing
and development involved testing, evaluation,
and formulation of source control materials for
application at the selected site.
Phase two will encompass the application of
three select source control materials at the
demonstration site and an evaluation of the
material application and feasibility. Long-term
evaluation of the materials will include air borne
particulate testing, moisture profiles generated
from reflectometers, in situ permeability tests
(using Guelph Permeameters), ex situ
permeability tests, and freeze/thaw testing
(flexible wall permeameter).
Status
The Mammoth Tailings site located adjacent to
the historic mining town of Mammoth, Montana
(see Figure 8) was the project site selected.
Material testing was completed during the first
quarter of 2000. Three source control materials
were applied at the site during the summer of
2001. These materials included two, polymeric
cementitious grouts that incorporate the tailings
material as a filler material (IESCRETE and
Krystal Bond) and a spray-applied, modified
polyurea chemical grout. Following a year of
moisture testing and material evaluation, the
project is scheduled to be completed by the end
of calendar year 2002.
23
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Figure 8. Mammoth Mine Tailings site.
ACTIVITY III, PROJECT 16:
INTEGRATED PASSIVE
BIOLOGICAL TREATMENT
PROCESS DEMONSTRATION
Project Overview
The objective of this project is to develop
technical information on the ability of an
integrated passive biological reactor to treat and
improve water quality at a remote mine site.
This technology offers advantages over many
acid mine drainage (AMD) treatment systems
because it does not require a power source or
frequent operator attention. For this
demonstration, the technology will treat the
acidic aqueous waste by removing toxic,
dissolved metallic and anionic constituents from
the water in situ and increasing the pH so the
effluent is near neutral.
Technology Description
The technology uses a series of biological
processes for the complete mitigation of AMD
by concentrating and immobilizing metals
within the reactors and raising the pH of the
water. Both anaerobic and aerobic bacteria are
used. The bacteria are fed inexpensive waste
products such as feedlot wastes. The sulphate-
reducing bacteria (SRB) are a group of common
bacteria that are able to neutralize AMD and
remove toxic metals. When supplied with
sulfate (present in mine water) and a carbon
source (composed of 50% cow manure and 50%
walnut shells), SRB produce bicarbonate and
hydrogen sulfide gas. Figure 9 shows the metals
removal results. Bicarbonate neutralizes AMD
while hydrogen sulfide gas reacts with metal
ions to precipitate them as insoluble metal
sulfides. Aerobic bacteria are used to mitigate
metals, such as iron and manganese, which are
not removed satisfactorily by SRB. The result
will be an integrated biological system capable
of completely and passively mitigating AMD.
The field system is depicted in Figure 10.
24
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In the first phase of the project, laboratory
testing was performed to identify design
parameters for the field design.
The second phase of the project was the design
and construction of an integrated passive
biological treatment system to treat AMD at the
Surething Mine located in Southwest Montana.
Status
The construction of the field-scale system was
completed in fiscal 2001.
O)
Out 0.051 0.064 0.004 0.006 0.336 0.04
Figure 9. September 2001 metal concentrations.
Acid Mine
Drainage
Treated
Discharge
Figure 10. Field system for integrated passive
biological treatment process demonstration.
25
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ACTIVITY III, PROJECT 16A:
SULFATE-REDUCING
BACTERIA-DRIVEN SULFIDE
PRECIPITATION
DEMONSTRATION PROJECT
Project Overview
Acid mine drainage (AMD), produced by
chemical and biological oxidation of sulfide
minerals, consists of acidic water containing
high concentrations of sulfate and dissolved
metals. Pollution of ground and surface water
by AMD is problematic at both active and
inactive mine sites. The use of sulfate-reducing
bacteria (SRB) to treat AMD is a promising
alternative to conventional treatment methods.
SRB oxidize organic matter under anaerobic
conditions using sulfate as a terminal electron
acceptor, resulting in sulfate removal and the
formation of sulfide and bicarbonate ions. The
sulfide produced can react with dissolved metals
in AMD, removing them from solution as
insoluble metal-sulfide complexes. The
alkalinity (bicarbonate) produced by SRB
metabolism is capable of buffering the acidity of
AMD.
Technical challenges in designing an SRB
treatment system for AMD include the fact that
the acidity and high metal concentrations of
AMD can be inhibitory or toxic to the bacteria.
Furthermore, the production of insoluble metal
sulfides and hydroxides in SRB bioreactors, as
well as the production of microbial biomass, can
lead to plugging of the reactor systems. These
challenges are being overcome in this project
using a novel two-stage SRB treatment system.
Bench-scale tests were conducted at the MSB
Testing Facility in Butte, Montana, to
demonstrate the feasibility of the concept. A
field-scale test system was constructed at
Golden Sunlight Mine near Whitehall Montana.
Initial results indicate the field scale system is
very effective for treating AMD emanating from
a large waste rock pile.
Technology Description
The SRB treatment system being evaluated in
this project consists of a two-stage reactor
design to separate the abiotic and biotic
reactions occurring during AMD treatment. In
the first stage of the process (settling pond),
AMD is mixed with water containing sulfide and
alkalinity generated by SRB metabolism in the
second stage of the process (bioreactor).
Following the abiotic buffering and metal-
precipitation reactions occurring in the settling
pond, the partially treated AMD enters the
bioreactor. The sulfate necessary for SRB
growth is provided by the AMD, and organic
carbon (methanol) is added to the settling pond.
A portion of the treated AMD from the
bioreactor effluent is recycled to the settling
pond, while the remainder is discharged. This
system design prevents direct exposure of the
SRB to the acidic metal-laden AMD and
prevents clogging of the biorector with metal
precipitates.
Status
Bench-scale testing of this technology was
completed in 2001. Acid mine drainage from
the Midas dump, a large waste rock pile, at
Golden Sunlight Mine was used in these tests.
Results of the bench-scale tests indicated this
was a feasible technology for treating AMD
from the Midas dump. Data from the bench-
scale tests was also used to estimate an
appropriate recycle rate for operating the field-
scale system. The field-scale system was
constructed at Golden Sunlight Mines in the
summer of 2001 and began operation in the fall
of 2001. The system was designed to treat
drainage from the Midas dump, which is
produced at rates of 1 to 3 gallons per minute.
Initial results indicate the system is significantly
improving the water quality of AMD from the
dump. The pH of the AMD from the Midas
dump was 2.7 ± 0.1, while the pH of the
bioreactor effluent has ranged from 5.3 to 6.4.
26
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The system has also been effective for removing
dissolved aluminum, copper, iron, and zinc from
the drainage. Overall, the results to date indicate
this is a very effective system for treating AMD.
ACTIVITY III, PROJECT 19:
SITE IN SITU MERCURY
STABILIZATION
TECHNOLOGIES
Project Overview
This demonstration project is being conducted in
conjunction with the U.S. Environmental
Protection Agency's Superfund Innovative
Technology Evaluation Demonstration Program.
Mercury contamination often is a critical
problem at mine sites, and there is a recognized
need to identify technologies for mercury
remediation. The application of an in situ
mercury stabilization technology would provide
an alternative treatment to completely removing
mercury-contaminated materials from remote
abandoned mine sites. As part of the overall
project, MSE Technology Applications, Inc.
(MSE) is responsible for conducting technology
assessment activities to comparative mercury
stabilization tests using mercury-contaminated
material.
The Sulphur Bank Mercury Mine (SBMM) in
Clear Lake, California, was chosen as the source
of mercury contaminated mining wastes for this
demonstration project. This abandoned mine
located in a geothermal active area was
historically mined for mercury and sulfur. It is
now part of a 120-acre superfund site containing
tailings, rock piles, and a pit lake. The mine
tailings are located upgradient and extend into
and along the shoreline of Clear Lake. The
development of an in situ mercury
treatment/stabilization technology could be used
to address the significant mercury contamination
problems at the site.
Technology Description
The main objective of this effort is to determine
a suitable method for in situ mercury
stabilization. An extensive treatability study
was performed on two mercury contaminated
SBMM materials by three types of stabilization
technologies. The primary objective of this
study was to determine the effectiveness of the
three stabilization technologies (silica
encapsulation, phosphate, and sulfide) in
reducing the quantity of leachable mercury from
SBMM material. Waste material evaluated in
this study consisted of "white material" from the
south white gate pile and "yellow material" from
the north yellow pile. The white material was
the primary test material due to its demonstrated
ability to produce consistent and detectable
levels of leachable mercury. The yellow
material was included because it is a common
material at the site, even though it yields lower
levels of leachable mercury.
To evaluate the performance of the three
technologies, the leachable and mobile mercury
(defined as the mercury in the <25-yWm filtered
leachate fraction) from control columns
receiving no treatment was compared to the
leachable and mobile mercury in the treatment
columns. Specifically, the objective was to
achieve a 90% reduction in the total mass of
mercury leached from each treatment relative to
the control over a 12-week continuous column
leaching study. The mass of mercury for each
treatment and control was calculated by
multiplying the mercury concentration of the
<25-pm fraction collected each week by the
volume of leachate collected, averaging the mass
for each set of replicate treatment or control
columns, and summing the total for the 12
weeks. The white material was used to evaluate
the primary objective in the column study, and
each treatment or control was run as triplicate
columns. As a secondary objective, and with no
quantitative reduction goals, the yellow material
was evaluated over a 12-week period in the
27
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column tests. In addition to mercury in the
leachate, the following parameters were
measured: pH, redox potential, sulfate, sulfide,
conductivity, alkalinity/acidity, turbidity, and
other metals (arsenic, iron, and antimony).
In addition to the column tests, kinetic testing
using the humidity cell procedure was run on the
control white material (no treatment) and treated
white material. Humidity cell testing, detailed in
ASTM D 5744-96, is a protocol designed to
meet kinetic testing regulatory requirements for
mining wastes and ores. In this test method, the
sample is subjected to alternate periods of dry
air, moist air, and water leaching in an effort to
simulate the weathering process that the ore
would undergo in a natural environment.
Status
The predemonstration leachability studies
revealed that the dominant form of leachable
mercury was in a particulate and mobile form.
These studies indicated that leaching with a
meteoric solution released particulates that
remained suspended in solution and, therefore,
could be mobile in a groundwater and/or surface
water hydraulic system. Levels of dissolved
mercury were low in these leaching studies. A
continuous column leaching test design was
used to collect effluent samples over a 12-week
period to evaluate leachable mercury in mobile
(<25 pm) and dissolved (<0.45 ^m) fractions
from treated and control columns. The
conventional phosphate treatment dramatically
increased the levels of mobile mercury (<25 jwm
fraction) over the course of the 12-week study.
A 94.7% increase in the total mass of mercury
leached occurred relative to the control. Sulfide
treatment did not appear to be effective in
reducing the levels of mobile mercury in the
column tests. There was no significant
difference in the cumulative levels of mobile
mercury in the effluent from the sulfide
treatment relative to the control. Silica
microencapsulation was effective in reducing
mobile mercury (<25 jwm) very close to the 90%
reduction goal of the study. However, the
dissolved mercury portion (<0.45 /u,m) of the
mobile fraction increased by approximately
200% relative to the control.
ACTIVITY III, PROJECT 21:
INTEGRATED PROCESS FOR
TREATMENT OF BERKELEY PIT
WATER
Project Overview
The objective of this project is to develop
integrated, optimized treatment systems for
processing Berkeley Pit water. The Berkeley Pit
is an inactive open-pit copper mine located in
Butte, Montana. Currently containing
approximately 30 billion gallons of acidic,
metals-laden water, the Berkeley Pit is filling at
a rate of approximately 3 million gallons per day
and is a good example of acid rock drainage.
Two optimized flow sheets will be developed for
this project. One flow sheet is to be oriented
toward minimizing the overall cost of water
treatment to meet discharge requirements—this
will include not only water treatment equipment
but also sludge handling/management. The
other flow sheet is to be oriented toward also
meeting discharge requirements but includes the
recovery of products from the water (copper,
metal sulfates, etc.) to potentially offset
treatment costs and result in overall better
economics.
Technology Description
The project will evaluate proven technologies
[e.g., precipitation (oxide/hydroxide, sulfide),
ion exchange, cementation, solvent extraction,
electrolysis, filtration options, etc.] as well as
technologies with credible pilot-scale supporting
data. Technology with only laboratory testing
history or with unverifiable pilot-scale data will
not be considered. The goal is to assemble the
sequence of unit operations resulting in the most
attractive overall economics, without relying on
relatively unproven technologies.
28
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Status
Technology Description
In FY 2001, a report documenting small-scale
testing to evaluate the effects of returning settled
sludges to the Berkeley Pit was completed and
issued. Information was gathered on a variety of
process options, including the use of high-
density sludge, and spreadsheets were prepared
evaluating a variety of metal recovery options to
evaluate the economics of potential
modifications. Options evaluated included
copper recovery as a sulfide, followed by
roasting to other forms; zinc recovery as a
sulfide and by solvent extraction, also followed
by various downstream process options;
aluminum recovery as an oxide; and various
others. Preliminary results showed that most of
the metals present cannot be profitably
recovered due to their low value and dilute
concentrations. Sulfide precipitation is an
attractive way to separate and recover copper
and zinc, but sulfide products are of very low
value, and on-site upgrading is needed to
potentially be profitable. Copper recovery is
viable but may not be more attractive than using
the existing cementation plant. Profitable zinc
recovery is very marginal at current prices.
Future plans are to issue a project final report in
FY 2002.
ACTIVITY III, PROJECT 22:
PHOSPHATE STABILIZATION
OF MINE WASTE
CONTAMINATED SOILS
Project Overview
The project goal is to provide information to
support technical feasibility and regulatory
acceptance of phosphoric acid-based in situ
stabilization of lead in residential soils at the
Joplin, Missouri National Priorities List Site.
The ultimate goal is to demonstrate this
technique is a cost-effective alternative to
excavation and haulage of metal-contaminated
soils to a waste repository.
The remediation approach involves mixing
commercial grade phosphoric acid and a trace of
potassium chloride into near surface soils,
followed by pH adjustment (e.g., with lime
addition) to attain paraneutrality. As a result,
soluble lead is converted to pyromorphite, a
highly insoluble and environmentally stable
mineral. Subsequently, lead uptake from rooting
zone soils (into aboveground plant biomass) and
into the bloodstream of young children (from the
gastrointestinal tract) is significantly reduced.
Status
The following activities were completed in fiscal
2001: sampling and analysis of soil and plant
materials collected from the field test plot;
dosing of young swine with soils from the test
plot; and laboratory characterization of the
treated soils. The overall results for mill tailings
receiving 1 percent by weight phosphoric acid
(as described above) were very promising. It
appears as though this treatment will
significantly reduce public health and
environmental risks due to exposure to these
contaminated soils. Additional work to verify
the pig dosing results will be completed in
FY 2002 and will be documented in the final
project report.
ACTIVITY III, PROJECT 23:
REVEGETATION OF MINING
WASTE USING ORGANIC
AMENDMENTS AND EVALUATE
THE POTENTIAL FOR
CREATING ATTRACTIVE
NUISANCES FOR WILDLIFE
Project Overview
The objectives of this project are to demonstrate
the use of organic amendments to enhance the
establishment and growth of grass on lead mine
tailings and to evaluate the affect of those
29
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amendments on plant uptake of metals. Two
sources of compost and an organic fertilizer
derived from municipal sewage treatment plant
sludge were incorporated into two types of
tailings near Desloge, Missouri, and the
replicated plots were planted with grass. Both
types of tailings (fine-textured floatation tailings
and course-textured gravity separation tailings
referred to as chat tailings) contain elevated
concentrations of lead, zinc, and cadmium. This
project will be evaluated for three growing
seasons.
Thousands of abandoned mine and mineral
processing sites throughout the United States are
very unattractive and can be a significant
environmental hazard. The federal government
and responsible parties need to develop cost-
effective remedial approaches to effectively
manage these large areas that are contaminated
with a wide variety of metals. Natural
revegetation is often prevented in these areas
because of low pH, phytotoxic concentrations of
metals, poor physical structure for plant growth,
nutrient deficiencies, and slopes too steep for
plant establishment. Mine waste reclamation
research frequently includes the addition of
organic soil amendments, since mine waste
materials are typically subsurface in origin and
have minimal organic content. However, the
diversity of organic amendments used and the
lack of uniformity within each category of
material make comparisons among sites and
studies difficult. In addition, while it is
generally agreed that organic amendments are
capable of stabilizing mine waste metals, the
potential for post reclamation impacts to wildlife
due to plant uptake of those metals requires
further research.
Technology Description
MSB Technology Applications, Inc., established
field plots at the Big River Mine Tailings Site
and the Leadwood Chat Tailings Site in
Missouri in the spring of 2000. The plots were
evaluated to determine vegetation establishment,
biomass production, and plant uptake of metals.
Procedures for establishing, maintaining, and
evaluating the plots will be broadly applicable
and reproducible so that subsequent studies at
other locations will produce comparable
information. The three organic amendments are
milorganite, ormiorganics compost, and St.
Peters compost. These amendments were
applied at a low, medium, and high application
rate. Each amendment/application rate
combination was replicated four times including
a control plot that only received the inorganic
fertilizer at both sites, totaling 80 plots. The
plant species for the demonstration was tall
fescue (Kentucky variety). The plots were
monitored monthly from May through
September 2000. The project will be evaluated
for three growing seasons.
Status
Figure 11 shows the Leadwood Chat Tailings
site prior to planting, Figure 12 shows the site
after the first growing season, and Figure 13
shows the site after the second growing season.
Figure 14 shows the Big River Mine Tailings
site prior to planting, Figure 15 shows the site
after the first growing season, and Figure 16
shows the site after the second growing season.
The results from the second year growing season
were compared to the first year growing season.
Preliminary results indicate that the cover and
production results had less vegetation compared
to the first year, which is largely due to the dry
season without irrigation. However, the
compost treatments have a considerable amount
of vegetation compared to the controls. In
general, both cover and production were
correlated with increasing application rates for
all treatment, which shows the benefits from
higher application rates. Overall, the plots have
easily vegetated and compost appears to reduce
metal uptake into the plants foliage compared to
the control plots.
Additional results of the second growing season
will be discussed in a Summary Report to be
issued in April 2002. The project will be
evaluated for a third growing season, and a Final
Report will be issued in March 2003.
30
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I I I -I
Figure 11. Leadwood Chat Tailings site prior to planting.
Figure 12. Leadwood Chat Tailings site after first growing season.
-31-
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Figure 13. Leadwood Chat Tailings Site after second growing season.
Figure 14. Big River Mine Tailings site prior to planting.
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I^^Bj&*
Figure 15. Big River Mine Tailings site after first growing season.
Figure 16. Big River Mine Tailings Site after second growing season.
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ACTIVITY III, PROJECT 24
IMPROVEMENTS IN
ENGINEERED
BIOREMEDIATION OF ACID
MINE DRAINAGE
Project Overview
Acid mine drainage (AMD) emanates from
many abandoned mine sites in the western
United States. Such drainage, having an
elevated content of dissolved metals and low
pH, presents an environmental problem that
needs to be economically addressed. Sulfate-
reducing bacteria (SRB) have the ability to
immobilize dissolved metals, by precipitating
them as sulfides, and increase pH provided that a
favorable biochemical environment is created.
Such conditions may be created by constructing
artificial wetlands, if space is not limited, or
converging the AMD flow to an engineered
passive SRB reactor.
A SRB reactor contains an organic-carbon
chamber that is vital for its operation. A life
span of a properly designed reactor depends on
the organic carbon supply, permeability of
organic-carbon chamber, and the capacity of the
reactor to accumulate precipitated sulfides.
When the source of organic carbon is depleted,
or becomes unavailable, because permeability of
the organic matter decreased due to settling
processes or physical or chemical encapsulation,
the bioreactor will cease operating. To
reactivate such a bioreactor, the organic carbon
source has to be either replenished or
rejuvenated. Therefore, it is desirable to: 1)
maximize the time interval between such
operations; and/or 2) be able to predict the
longevity of the carbon source to economically
optimize the reactor's size.
Similarly, when the capacity of the bioreactor's
chamber that was designed to hold precipitated
sulfides is exhausted, the sulfides will either
break through or the reactor will plug ceasing its
operation.
This project addresses engineering
improvements that include replacing the organic
carbon supply-system in a SRB reactor and
refining how the reactor is sized.
Technology Description
Engineered improvements of SRB reactors are
to be accomplished by implementing the four
tasks listed below.
Task I Selecting Optimal Media with
Organic Carbon
The optimal media needs to: 1) contain a
sufficient amount of organic carbon; 2) be used
economically as passive SRB bioreactors; and 3)
have high potential to be permeable when
saturated with water. Determination of the
optimal organic carbon media will be done
through a literature study. A database was set
up that included the media technical parameters,
records of use, availability, price index, etc.
Task II Designing a Permeability and
Contact Time Enhancing System
(PACTES)
PACTES will ensure a good supply of organic
carbon and will maintain good permeability of
the organic matter throughout the predicted life
of the reactor.
Task Ill-Designing an Organic
Carbon Replaceable Cartridge
System (RCS)
A replaceable cartridge system will be easy to
install and replace in a bioreactor, particularly at
a remote location.
To ensure that PACTES and RCS systems are
compatible, their development was symbiotic.
Work on each system included the following
phases: 1) developing a list of concepts for each
system; 2) narrowing the list to the most (one)
applicable solution; 3) laboratory testing of the
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selected solution; 4) preparing the design
document; 5) constructing the prototype of the
RCS combined with PACTES; and 6) bench-test
study of the constructed prototype.
Task IV-Developing a Computer
Software to Simulate SRB Activities
in the Bioreactor
The software will enable a designer to efficiently
design and size a bioreactor by quantifying the
expected rate of organic carbon depletion and
the volume of SRB activity by-products.
Status
Task I was completed, and a report of the
findings entitled Evaluation of Organic
Substrates for the Growth of Sulfate-Reduction
Bacteria to Treat Acid Mine Drainage was
prepared. The report contained the Microsoft
Access database that included information
obtained from more than 90 publications that
identified 36 organic substrates; among them, 7
substances were direct, e.g. methanol, lactate,
etc., and 29 were indirect, e.g. manure, sludge,
wood waste, etc.
The following conclusions were reached upon
completing this task.
• Selecting an organic substrate should be
based on effectiveness, cost, and availability.
• A mixture of substrates, with varying degrees
of biodegradability, provides the best long-
term bioreactor performance.
• Directly utilizable SRB substrates can be
used to either initiate the SRB activity or
restore the activity to spent organic media.
• The suitability of a substrate mixture for
treating a particular AMD is best assessed
empirically using laboratory tests.
As a result of the investigation conducted for
Task I, a mixture of walnut shells and cow
manure was selected as the optimum organic
medium for the project. Cow manure is readily
biodegradable, and the slow biodegradable
walnut shells enhance long-term performance of
the bioreactors and provide a structure for the
organic medium to prevent it from settling.
Task II, development of PACTES, was
completed. The PACTES consisted of a mixture
of walnut shells and manure prepacked in
plastic-net socks, approximately 1 cubic foot in
volume. The mix consisted of 50% manure and
50% walnut shells by volume.
Task III was also advanced to the development
of concepts for the RCS that currently includes a
pattern of pipes filled with PACTES. The pipes
will be placed in a container through which the
AMD will flow in a vertical direction collinear
with the axes of the pipes.
Initial work on Task IV identified an existing
software, MINTEQAK, that was developed to
simulate biochemical processes occurring in
wetlands. This software must be modified to
enable input of variables for the time and spatial
coordinates.
Work on the project will continue into the end of
fiscal 2002.
ACTIVITY III, PROJECT 25
PASSIVE ARSENIC REMOVAL
DEMONSTRATION PROJECT
Project Overview
The objective of this project is to evaluate
bench-scale, innovative, passive arsenic removal
technologies with applicability to remote mine
sites. By conducting this demonstration, the
Mine Waste Technology Program (MWTP) will
illustrate the functional and operational
requirements of passive arsenic technologies and
how these technologies can be used to alleviate
the environmental problems associated with
acidic, metal-laden mine drainage.
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Technology Description
This project will evaluate passive technologies
capable of removing arsenic from mine
drainage. The most effective conventional
arsenic treatment technologies are ferric
hydroxide and magnesium hydroxide
adsorption/precipitation. However, these
methods are not adaptable to remote locations
due to their chemical process nature.
Technologies capable of passively removing
arsenic from mine drainage include using
various fine-grain sands such as manganese-
dioxide-coated sand and granular ferric
hydroxide in gravity-fed reactors.
Status
The first phase of this project identified passive
arsenic treatment technologies. Several media
were selected for laboratory column testing (see
Figure 17). These media were manganese-
dioxide-coated sand (Greensand), granular
activated alumina, granular ferric hydroxide,
iron filings, limestone, apatite, granular sulfide,
and granular activated carbon. Silica sand was
selected as the control media.
Water from the Susie/Valley Forge Mine in
Rimini, Montana, was used for testing. Through
500 pour volumes, all test media, with the
exception of apatite, removed over 99% of the
arsenic (see Table 2). The next poorest
treatment was the activated carbon column.
Since the dissolved iron to arsenic ratio of the
Susie/Valley Forge Mine water was notably
high, some of the arsenic removal may have
been attributed directly to pH adjustment and the
resulting ferric hydride/arsenic coprecipitation.
Water with a lower iron to arsenic ratio was not
tested; therefore, the efficiency of the tested
arsenic treatment technologies is unknown for
these types of waters.
Table 2. Results of laboratory column testing.
Pour Magnesium Ferric
Volumes Dioxide Hydroxide
100
200
300
400
500
Activated
Alumna
Limestone Sulfide
Activated
Iron Carbon Apatite
100.0%
99.5%
99.5%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
99.7%
100.0%
100.0%
100.0%
99.7%
100.0%
100.0%
99.7%
100.0%
100.0%
100.0%
99.7%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
99.4%
97.9%
99.2%
99.7%
99.4%
96.7%
96.0%
97.9%
91.4%
97.5%
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Figure 17. Laboratory column testing of media at the MSE Testing
Facility in Butte, Montana.
ACTIVITY III, PROJECT 26
PREVENTION OF ACID MINE
DRAINAGE GENERATION FROM
OPEN-PIT MINE HIGHWALLS
Project Overview
Exposed, open-pit mine highwalls contribute
significantly to the production of acid mine
drainage (AMD) and can be problematic upon
closure of an operating mine. Four innovative
technologies were evaluated under the Mine
Waste Technology (MWTP), Prevention of
AMD Generation from Open-Pit Highwalls
Demonstration Project. The objective of the
field demonstration was to evaluate technologies
for their ability to decrease or eliminate acid
generation from treated areas of the highwall,
compared to untreated highwall areas.
Technology Description
Generation of AMD from open-pit mine
highwalls has been addressed in a limited
manner, and little information is available on the
subject. Most likely, this is due to the difficulty
and danger of physically working on or near the
face of the highwall. Other areas of concern
such as mine tailings, underground workings and
other above ground waste rock piles can usually
be dealt with by physical means to control the
generation of AMD, i.e., removal or application
of a permanent impermeable cover. However,
highwall generated AMD will continue to be
produced for indefinite periods of time as
weathering occurs and the flushing action of
atmospheric precipitation and/or groundwater
infiltration through the highwall takes place.
The main purpose of this project is to research
technologies applicable to controlling or
eliminating AMD generated from open-pit mine
highwalls and then apply and monitor the
potential technologies under actual field
conditions. For this demonstration, four
technologies having potential to passivate the
AMD from a highwall were selected. The
application methods required to apply each
technology varied along with the application
time and the materials.
The demonstration consists of three phases: 1)
extensive site characterization and gathering
background information; 2) technology
identification and field application; and 3) long-
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term field monitoring and laboratory testing for
confirmation of field results.
Site characterization in Phase I will include core
drilling the highwall to determine geology,
hydrogeology, and extent and depth of acid
generation (i.e. geochemical analysis), and
performing background sampling at all of the
sampling ports placed on the highwall.
The third phase of the project involves
monitoring the technologies using ASTMD
5744-96, Accelerated Weathering of Solid
Materials using a Modified Humidity Cells,
residual wall rinse samples from the treated
highwall plots, microscopy, and other methods.
Status
The field demonstration was performed at the
Golden Sunlight Mine (GSM), a subsidiary of
Placer Dome, an operating gold mine located
near Whitehall, Montana. The ore body at GSM
is sulfidic, and the exposed highwall provides an
AMD source.
Phase one, site characterization, was competed
in September 2001.
Phase two, included selecting four technologies,
was completed by May 2001. Placement of the
technologies is scheduled for early FY02.
ACTIVITY III, PROJECT 27
REMEDIATING SOIL AND
GROUNDWATER WITH
ORGANIC APATITE
Project Overview
Apatite remediation of heavy metals is an
emerging technology that addresses the need to
remediate metals in wastes, contaminated
groundwater, sediments and soils, including
agricultural soils. Metals readily leach from
contaminated soils and sediments serving as a
constant source of metal contamination to
surface waters, underlying groundwater zones,
and ingestion pathways of the biota. Efforts to
mobilize and remove metals from the subsurface
to below regulatory or risk-based limits have
been unsuccessful due to the various
intermediate solubilities and sorption properties
that each metal and suite of metals exhibits
under most environmental conditions. Total
removal of the contaminated material for
disposal elsewhere is not feasible, as it exceeds
all landfill space presently available.
Alternatively, metals can be stabilized in place
to prevent them from migrating or leaching into
groundwater or accumulating in the ecosystem.
Many materials have been proposed for this
purpose, but the technology described here is
particularly effective for nonredox-sensitive
metals for which no adequate, cost-effective
alternatives exist, e.g., lead, cadmium and
uranium. This technology stabilizes metals by
chemically binding them into new stable
phosphate phases (apatite minerals) and other
relatively insoluble phases in the soil, sediment,
or in a permeable reactive groundwater barrier.
Metals most effectively stabilized by this
treatment are lead, uranium, zinc, copper,
cadmium, nickel, barium, cesium, strontium,
plutonium, thorium, and other lanthanides and
actinides. Because of its high toxicity, lead has
been the focus of some previous studies by other
investigators. In addition to lead, this study will
focus on other contaminants of concern
frequently associated with mining derived
wastes such as arsenic, cadmium, copper,
mercury, and zinc.
Technology Description
The objective of the project is to determine the
efficacy of metal cation removal by Apatite II
from contaminated soil and groundwater. The
technical information will be summarized in a
final report, which represents the complete
product of the project.
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Technical objectives include:
- demonstrating that statistically significant
metal cation removal can be achieved with
Apatite II amendments to the soil or
treating the groundwater;
- evaluating the long-term stability of the
removed reaction products of cations with
Apatite II;
- determining if field-scale studies with the
material are warranted; and
- verifying that the technology is applicable
at field scale.
Status
During FY-01 the project was initiated with
preparation of the Work Plan and selection of
sites for soil collection to use in the first phase
of laboratory treatability studies.
• Batch reactor tests have been completed.
These first two sets of samples were from
areas along Silver Bow Creek near Butte,
Montana, impacted by acid mine drainage
and mill tailings. One area exhibited mercury
and uranium levels above background as well
as high levels of copper and zinc. The third
and fourth sets of samples are from the
Mammoth tailings near Mammoth, Montana.
The fifth set is from the Joplin, Missouri, lead
district. Apatite to soil concentrations that
were initially tested for all sample sets are 1,
5, and 10 percent. Preliminary results
indicated that the optimum apatite to soil
ratio is between 1 and 5 percent. Therefore,
an additional 1-week batch reactor test was
performed with an apatite to soil ratio of 3
percent.
• The laboratory data is being evaluated before
initiating the humidity cell tests. The
humidity cells have been fabricated. The test
equipment will simulate vadose zone soil
conditions.
ACTIVITY III, PROJECT 29
REMEDIATION TECHNOLOGY
EVALUATION AT THE GILT
EDGE MINE
Project Overview
The objective of this project is to generate
performance and cost data for promising new
technologies for preventing the oxidation of
sulfide waste rock, which may be applicable to
many mine waste sites. The new technologies
will be compared to the presumptive remedy of
lime treatment as well as to controls in which no
treatment is performed. The technology
demonstration will be performed at the Gilt
Edge Mine, a 270-acre, open-pit cyanide heap
leach gold mine located about 5 miles southeast
of Lead, South Dakota. The immediate area was
the site of sporadic mining activity for over 100
years. The Gilt Edge Mine was operated by
Brohm Mining Corporation, a wholly owned
subsidiary of Dakota Mining Cooperation from
February 1986 until July 1999. Brohm's
activities included developing several open pits,
crushing and placing the ore on a heap leach pad
for gold leaching by cyanidation, and Merrill-
Crowe gold recovery in an on-site mill. In July
1999, the mine's owners (Dakota Mining
Corporation) declared bankruptcy, resulting in
the Gilt Edge site being returned to the State of
South Dakota for management. After incurring
significant costs for water treatment to ensure no
discharge of acidic mine water to the
environment occurred, the State of South Dakota
requested that EPA Region VIII take over the
site and list it on the National Priorities List
(NPL) as a Superfund site. The Gilt Edge Mine
site presents an opportunity to evaluate
emerging acid mine drainage (AMD)-treatment
technologies while gathering data leading to a
Record of Decision (ROD) for the site.
-39-
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This project is a collaboration between EPA
Region VIII and the EPA Mine Waste
Technology Program (MWTP). The objective
of Region VIII is to conduct a treatability study
as part of the remedial investigation/feasibility
study process for the site—providing data to
help make decisions supporting the ROD for the
site. The technical and economic information
will be summarized in a final report.
The project involves constructing test cells,
which will be loaded with sulfide-bearing waste
rock from the Gilt Edge Mine site. EPA Region
VIII (or its contractors), assisted by the U.S.
Bureau of Reclamation will design and construct
the test cells, as well as load the waste rock.
Three technology providers will each install its
respective technology for reducing AMD
generated by the waste rock. The project will
take place west of the Anchor Hill Pit at the Gilt
Edge Mine. The test cells will receive ambient
precipitation, and an irrigation system will apply
additional simulated precipitation to the test
cells. A system for managing and sampling
leachate quality designed by EPA Region VIII
will be integrated into the cell design. Twelve
test cells are planned. Two cells are dedicated to
each of the three technologies to show
performance repeatability. Three control cells
containing only waste rock (with no additional
treatment) and three cells representing the
presumptive remedy of blending lime with the
waste rock will also be constructed. The
performance of the installed technologies will be
judged primarily by comparing leachate water
quality from the installed technology cells with
that of the control and presumptive remedy cells.
The test cells will be constructed and loaded in
September 2000. EPA Region VIII will monitor
for 1 year; thereafter, the monitoring
responsibility will be transferred to MWTP,
while EPA Region VIII uses the generated data
in preparing the site ROD. Monitoring will
continue for at least 1 additional year, with
following years added if budget allows and if
observed results make it advisable to do so.
Technology Description
The three technologies to be demonstrated are:
• Silica microencapsulation [Klean Earth
Environmental Company (KEECO)];
• Envirobond [Metals Treatment Technologies
(MTT)]; and
• Passivation technology [Mackay School of
Mines, University of Nevada, Reno (UNR)]
KEECO has developed a treatment technology
for treating and preventing metals-contaminated
waters, soils, and possibly sulfidic waste rock
called silica microencapsulation (SME). This
technology encapsulates metals in an impervious
microscopic silica matrix (essentially locking
them up in very small sand-like particles) that
prevents the metals from leaching and migrating.
Its chemical components react when introduced
to water, creating an initial pH adjustment and
electrokinetic reaction. The electrokinetic
reaction serves to facilitate electrokinetic
transport of metal particles toward the reactive
components of the SME product, enhancing its
efficiency. Metal hydroxyl formation follows;
next, silica encapsulation of the metals occurs,
forming a dense, stable coating. Contrary to
conventional treatment process where sludges
typically degrade over time, the SME silica
matrix appears to continue to strengthen and
tighten, providing for long-term isolation of
contaminants from the environment. Silica
microencapsulation has been applied to
wastewater, sediment, sludge, soil, mine tailings,
and other complex media but has never been
applied and tested directly on sulfidic mine
waste rock materials.
The Envirobond (Metals Treatment
Technologies) technology is similar to the
KEECO technology except that it involves
phosphate stabilization chemistry rather than
silicates. The technology has been applied at
mining sites, firing ranges, sediment removal
-40-
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sites, and others to produce a solid treatment
material meeting Toxicity Characteristic
Leaching Procedure criteria. The technology
can be adapted for a variety of wastestreams and
soil conditions.
Over the past few years, DuPont developed a
novel coating method known as a passivation
technology. Recently, the technology was
donated to UNR for further development and
commercialization. The passivation process
essentially creates an inert layer on the sulfide
phase by contacting the sulfide with a basic
permanganate solution to produce an inert
manganese-iron oxide layer. This layer prevents
contact with atmospheric oxygen during
weathering of the sulfide rock, thus, preventing
sulfuric acid generation. Another critical
element of the process is the addition of trace
amounts of magnesium oxide during pH
adjustment. Magnesium oxide addition
enhances the coating strength.
Status
The treatment cells were loaded and treated by
the technology vendors in November 2000.
Treatment monitoring started in May 2001 and
continued through October 2001, when the cells
froze. Monitoring will resume in the spring of
2002 when the cells thaw and will continue into
the fall of 2002. Data from 2001 is still in the
validation process; however, preliminary results
show all treatment technologies reduced most
metals concentrations and raised the pH of the
cell effluent. Figures 18 and 19 illustrate the
copper and pH trends for the treatment
technologies through October 2001.
1.E+05
0 1.E+01 -
1.E+00
Apr-01 May-01 May-01 Jun-01 Jul-01 Jul-01 Aug-01 Sep-01 Sep-01 Oct-01 Nov-01
Date
'KEECO
'Presumptive Remedy ^^^Control
Figure 18. Copper trends.
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Apr-01 May-01 May-01 Jun-01 Jul-01 Jul-01 Aug-01 Sep-01 Sep-01 Oct-01 Nov-01
Date
"KEECO
Presumptive Remedy
Figure 19. pH trends.
ACTIVITY III, PROJECT 30
ACIDIC/HEAVY METAL-
TOLERANT PLANT CULTIVARS
DEMONSTRATION, ANACONDA
SMELTER SUPERFUND SITE
Project Overview
Presently, grass, forb, and shrub species
commercially available for reclaiming
acidic/heavy metals-contaminated (A/M) soils
often come from outside the Northern Rocky
Mountain region. These cultivated varieties may
not tolerate the climatic-edaphic stresses (in
addition to A/M stresses) as well as would A/M
ecotypes indigenous to the region. Over the past
several years, plant populations exhibiting A/M
tolerance potential have been collected from the
Anaconda Smelter Superfund Site and evaluated
in laboratory, greenhouse, and preliminary field
trial studies. The results indicate that self-
sustaining plant communities comprised of
native A/M tolerant ecotypes are possible. Thus,
the goal of this project is to formally compare
the performance of local seed mixes against
comparable mixes now commercially available.
If the local ecotypes (of the given grass/forb
species) are indeed best performing, they would
be made available for full-scale reclamation of
hardrock mine/mill/smelter sites in the region.
Technology Description
The team comprised of the Deer Lodge Valley
Conservation District (DLVCD), USDA/Bridger
Plant Materials Center (BPMC), and MSB
Technology Applications, Inc., will select and
evaluate the most promising grass/forb
accessions at two test sites in the Anaconda area
over the 2002-2004 growing seasons. Shrub
species will be evaluated at a third site that is not
formally part of the Mine Waste Technology
Program funded study. Four grass/forb mixtures
from southwestern Montana will be compared
against four very similar mixtures of
commercially available cultivars. Four
replications of each mixture will be at both the
upland (Stucky Ridge) and lowland (Mill Creek)
test sites. The laboratory and field data gathered
during the three seasons will be statistically
analyzed to determine whether any of the local
seed mixes outperforms their commercial
counterparts.
-42-
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Status
The following project planning documents were
completed in fiscal 2001: work plan, quality
assurance project plan; NEPA compliance/site
access agreements; health and safety plan; and
subcontract with DLVCD-BPMC. The
following activities continued: collection and
laboratory analysis of plant and soil samples
from the Anaconda area; greenhouse and field
evaluations of plant performance; and
production of seeds (at BPMC) from the most
promising grass/forb accessions. The two test
sites were prepared for planting (in fiscal 2002),
and baseline soil samples were collected for
target heavy metals levels analysis. The
laboratory results (in Table 3) indicate the
general suitability of these sites as a test bed for
this project.
Table 3. Development of Acid/Metal Tolerant Cultivars Project: Baseline
Soils Data Summary11
A. Upl£
DLVCD-
BPMC
MSE
B. Low
DLVCD-
BPMC
MSE
Notes:
b r
1
and/Stucky Ridge Plot
AS r.H r.ii
131
178
land/Mil
As
386
493
2
1.8
Creek F
8
10
502
779
'lot
CLL
676
858
Eh
44
66
Eh
174
212
Zn
133
161
Zn
464
650
pH /
5.5 /
4.7 /
pH /
6.2 /
5.8 /
Eh
380
302
Eh
323
262
^cid-extractable metals in mg/kg; pH in S.U. and Eh in mv
J values are ^ threshold of concern levels, from QAPP;
evel for Pb is > 400 mg/kg
ACTIVITY III, PROJECT 31
REMOTE AUTONOMOUS MINE
MONITOR
Project Overview
Monitoring groundwater in the vicinity of mines
for heavy metal contamination can be
problematic in remote locations, especially when
extreme weather conditions exist. One solution
to this difficulty is an autonomous system
capable of monitoring mine waters at remote
locations for the presence of heavy metals.
Typical metals concentrations that might be
expected are shown in Table 4. Thus, an
autonomous system should be able to measure
metals at subparts per million (submilligrams
per liter (mg/L) levels to be effective. The
objective of this project is to test and evaluate a
monitor for heavy metals in a controlled
laboratory setting.
The project is divided into three phases:
• Phase I-Optimize Buffer
Formulations/Determine Appropriate
Detector;
• Phase II-Prototype Development/Laboratory
Demonstration; and
• Phase Ill-Field Installation and
Demonstration.
-43-
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During FY 2001, Phase I was partially
completed.
Technology Description
The remote mine monitor has three main
subsystems: a capillary electrophoresis
analyzer; a single board computer; and a satellite
telemetry link. The electrophoresis system will
be based on an automated system developed and
tested for NASA space applications. The NASA
system measures a number of components of
astronaut urine. The NASA system is fully
automated. Some alterations in the system must
be made to accommodate the remote mine
monitoring application.
Figure 20 shows a rear view of the NASA
automated system. The mine monitor would
remain essentially the same. The only
modifications envisioned include: enlarging the
buffer and sodium hydroxide tanks to
accommodate long deployment times and adding
a pump to draw well water samples to deliver to
the nanoliter syringe pump that delivers the
sample to the electrophoresis device. This pump
will also need to be incorporated into the control
system. Both of these changes are relatively
minor engineering changes. Once these changes
have been made, further laboratory testing will
establish how many analyses can be run on a
single capillary tube before replacement is
required. This information is essential to
examining sample rate versus unattended
deployment time issues.
Power consumption issues are important. At
this time, it is assumed that a battery bank will
be used to power the field deployable monitor.
The type and charging method for such a battery
bank would be site dependent and will not be
considered as part of this proof-of-principle
project.
Status
During FY 2001, the Johns Hopkins University
Applied Physics Laboratory (JHU/APL)
optimized the buffer formulations for the metals
of interest. The optimum separation buffer was
2 mM 8-hydroxyquinoline-5-sulfonic acid
(HQS), 10 mM phosphate, and 6 mM borate
adjusted to pH 8.0 with sodium hydroxide.
Work in FY 2002 will specify the detector that
will be used on the prototype instrument. The
final products of Phase I work will be the
optimal buffer and design specifications for the
detector, which will be included in a summary
report drafted by JHU/APL.
If Phase I of the testing program is promising,
JHU/APL may be funded to assemble a
prototype instrument based upon component
subsystems developed or under development at
JHU/APL that is capable of meeting the
requirements articulated above. JHU/APL
would assemble and laboratory test the
prototype as a of proof-of-principle exercise
during Phase II. MSB Technology Applications,
Inc., would serve as the verification entity and
support the laboratory testing portion of the
project. If the laboratory testing phase is
successful (i.e., the mine monitor could
accurately and precisely detect the metals of
interest), a field test of the mine monitor system
may be funded as Phase III of the project.
Table 4. Sample mine metal concentrations.
Al
Cu
Fe
Mn
Zn
Calliope
14.1
3.08
7.2
3.7
11.1
Concentration (mg/1)
Peerless
2.08
0.873
0.237
14.6
6.36
Lilly Orphan Boy
3.11
0.142
5.82
6.05
15.70
Crystal
22.0
25.7
105.0
13.7
80.6
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Figure 20. Rear view of the NASA monitor system
ACTIVITY III, PROJECT 33
MICROENCAPSULATION TO
PREVENT ACID MINE
DRAINAGE
Project Overview
This project is a laboratory-scale demonstration
project and is being conducted on a cost share
basis with the Minnesota Department of Natural
Resources. The objective of the project is to
evaluate the potential field application success
of commercial microencapsulation products to
prevent acid mine drainage on a mine waste
material. This demonstration serves as an
evaluation of the effectiveness of the technology
approach and will also be used to estimate field
application requirements.
Technology Description
Two technologies, Klean Earth Environmental
Company (KEECO) and Envirobond, are being
evaluated in comparative laboratory studies
using modified humidity cells. The KEECO
KB-SEA process employs a silica
microencapsulation treatment that acts to
encapsulate solid media particles. The materials
become stabilized as this silica coating helps to
control future acid generation. The Envirobond
process works to prevent the leaching of metal
contaminates by creating an impenetrable
chemical bond.
Status
Cell testing started in May 2001. All treatment
reagents were supplied and applied by the
technology vendors. The test cells are scheduled
for 16 months or until treatment is no longer
effective. Initial effluent pH results of the first
weeks of testing as compared to a control are
presented in Figure 21. Generally, the data
shows that both technologies offer some ability
to prevent the generation of an acidic leachate.
A full report with test data and materials
characterization results will be issued at the
completion of the project.
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"CONTROL —<^KEECO ENVIROBOND
Q.
0 2 4 6 8 10
Week / Leach Event
Figure 21. Initial microencapsulation cell test results.
ACTIVITY III, PROJECT 34
BIOREMEDIATION OF PIT
LAKES (GILT EDGE MINE)
Project Overview
This project is being conducted at the Gilt Edge
Mine Superfund site near Deadwood, South
Dakota. The project is a collaboration between
the Mine Waste Technology Program (MWTP)
and the EPA Region VIII Superfund office.
MWTP is taking the prime role in this project
with support from EPA Region VIII. EPA
Region VIII's interest is to conduct a treatability
study as part of the site Remedial Investigation/
Feasibility Study (RI/FS) process, while
MWTP's interest is to develop data applicable to
other similar sites. An in situ treatment of the
Anchor Hill Pit, an open pit at the Gilt Edge site
containing approximately 70 million gallons of
acidic water containing high levels of metals,
sulfate, and nitrate, will be performed. The
treatment will consist of an initial neutralization
step followed by a biological treatment to further
improve water quality and create a long-term,
stable system. After the two-step
treatment, the project will enter a monitoring
mode where the pit lake will be physically and
chemically characterized on a quarterly basis for
several years. The monitoring will show how
well the treatments work and how stable the pit
lake water becomes, e.g., if metal sulfides are
produced, does the system reoxidize and
remobilize those metals.
Technology Description
After initial chemical/physical characterization
of the pit lake, the neutralization step will be
implemented by Shepherd-Miller, Inc. (SMI) of
Fort Collins, Colorado, under subcontract to
MSE Technology Applications, Inc. (MSE).
SMI will use a Neutra-Mill fed with lime (CaO).
The Neutra-Mill is simply a floating platform
containing an apparatus to mix a reagent in with
the water it is floating on (see Figure 22). The
Neutra-Mill was developed by Earth System,
Pty. of Australia; SMI holds the United States
license to apply the technology. MSE and SMI
will take the lead in carrying out the
neutralization with assistance from EPA Region
VIII and its contractors.
-46-
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After neutralization, the pit will be allowed to sit
undisturbed for several weeks to allow
precipitated solids to settle and the system to
stabilize. After stabilization, the pit lake will
once again be characterized. Thereafter,
material consisting of methanol, molasses, and
phosphoric acid will be added to the pit lake.
This mixture has been patented by Green World
Science, Inc., of Boise, Idaho. The purpose of
the organic carbon addition is to produce
reducing conditions in the water and stimulate
the activity of indigenous bacteria. This should
have the effect of reducing or eliminating
nitrate/nitrite and selenium, and polishing toxic
metals concentrations to very low levels by
precipitating them as sulfides (produced by
reducing some sulfate to sulfide by sulfate-
reducing bacteria activity), and adding
bicarbonate alkalinity to the water to provide
buffering capacity.
Status
Project accomplishments in FY 2001 included
developing a project work plan; initiating
subcontracts with the technology providers
(Shepherd-Miller, Inc. and Green World
Science, Inc.); developing a quality assurance
project plan; initial sampling of the Anchor Hill
Pit water and sediment; neutralizing the Pit
using the Neutra-Mill and lime (CaO);
additional sampling of the Pit water and
sediment; dosing with methanol, molasses, and
phosphoric acid to initiate biological treatment
(see Figures 23 and 24); and initiating quarterly
monitoring of the Pit water after organic dosage.
Water samples are being collected quarterly at
two depths at each of two lateral locations.
Sediment samples are being collected annually
at the two lateral locations.
Neutralizing the Anchor Hill Pit consumed
approximately 290 tons of lime. Based on the
initial acidity of the water and neutralization
potential of the lime, this represents an
efficiency of approximately 70%, as compared
with a performance goal of 85% set by SMI.
However, it should be noted that the excess lime
settled to the bottom of the Pit and will serve as
an additional alkalinity source in the future.
Initial results from sampling after adding
nutrients to the Pit indicate that the biological
treatment was proceeding slowly. The
nitrate/nitrite concentrations were decreasing,
and selenium concentrations were decreasing.
No sulfate reduction had yet occurred; however,
no sulfate reduction is expected until
denitrification is complete.
Figure 22. Neutra-Mill and feed hopper.
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Figure 23. Molasses addition.
Figure 24. Methanol addition.
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ACTIVITY III, PROJECT 35
BIOLOGICAL PREVENTION OF
ACID MINE DRAINAGE (GILT
EDGE MINE)
Project Overview
This project is a collaboration between the U.S.
Environmental Protection Agency (EPA) Region
VIII and EPA Office of Research and
Development's (ORD) Mine Waste Technology
Program (MWTP). The goal of this project is to
evaluate the Shepherd-Miller, Inc. (SMI) Redox-
Mediated Biotransformation (RMB) technology
and determine cost, performance, and long-term
stability for SMFs RMB technology. MWTP is
responsible to provide a subcontract to SMI,
while EPA Region VIII will conduct the
technology demonstration. The technology will
be demonstrated at the Gilt Edge Mine, a 270-
acre open-pit cyanide heap leach gold mine
located about 5 miles southeast of Lead, South
Dakota. The immediate area was the site of
sporadic mining activity for over 100 years. The
Gilt Edge Mine was operated by Brohm Mining
Corporation, a wholly owned subsidiary of
Dakota Mining Cooperation from February 1986
until July 1999. Brohm's activities included
developing several open pits, crushing, and
placing ore on a heap leach pad for gold
leaching by cyanidation, and Merrill-Crowe gold
recovery in an on-site mill. In July 1999, the
mine's owners (Dakota Mining Corporation)
declared bankruptcy, resulting in the Gilt Edge
site being returned to the State of South Dakota
for management. After incurring significant
costs for water treatment to ensure no discharge
of acidic mine water to the environment
occurred, the State of South Dakota requested
that EPA Region VIII take over the site and list
it on the National Priorities List (NPL) as a
Superfund site. The Gilt Edge Mine site
presents an opportunity to evaluate emerging
acid mine drainage treatment technologies while
gathering data leading to a Record of Decision
for the site.
The RMB technology will be implemented in
Gilt Edge's high-density polyethylene (HPDE)-
lined neutralization pond. The pond's base
footprint is approximately 80 feet wide by 80
feet long and 15 feet deep with 2 to 1 sloped
walls. The pond will contain between 5,000 to
8,000 cubic yards of sulfide waste rock obtained
from the Ruby Waste Rock Dump.
Approximately 25,000 gallons of water will be
placed in the pond containing the waste rock to
mimic a backfilled pit lake. The Oro Fino shaft
will provide the groundwater used to fill waste
rock interstial voids.
Technology Description
The RMB technology is an in situ biological
treatment technology designed to reductively
remove nitrate, sulfate, metals, and metalloids
from mine wastewater. This reduction process
forms precipitates such as elemental selenium,
metal sulfide s, and elemental sulfur. The
transformation of aqueous constituents to the
solid phase improves the water quality in the
pond and the stability of these precipitates can
be maintained for long periods if proper
reducing conditions are maintained in the pond.
The RMB technology was developed by Green
World Science, Inc., and is covered by patents
granted (U.S. patents 5,632,715 and 5,710,361)
and others pending.
The RMB technology involves adding a
proprietary mixture developed by Green World
Science, Inc., containing organic carbon
(primarily sugars and alcohols) material and
biological nutrients to the pond water. Adding
organic carbon materials will create reducing
conditions within the pond and stimulate activity
of indigenous sulfate- and iron-reducing
bacteria. These bacteria will oxidize the carbon
to bicarbonate and reduce sulfate to the sulfide
form. This, in turn, will improve water quality
within the pond—bicarbonate will provide
alkalinity and buffering capacity while the
sulfide produced will facilitate removing metals
via the formation of stable metal-sulfide
precipitates.
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The pond water will be characterized physically
and chemically before organic dosage. After
organic dosage, EPA Region VIII will monitor
the pond for at least 1 year to assess the long-
term stability of the system set up by the RMB
technology. Untreated wasterock will be
isolated in 4-foot-diameter tanks to isolate the
wasterock and serve as a background for
comparing the technology.
Status
The pond was loaded and treated by Green
World Science in June 2001. EPA Region VIII
monitored the water levels, and it was evident by
July 2001 the pond had a leak. EPA Region
VIII made an effort to remedy the problem by
refilling the pond using water from the
secondary containment; however, the pond still
leaked, and new water had to be added several
times. Due to the constant fluctuation and flux
of water through the pond, the RMB technology
could not be evaluated accurately. As a result,
MWTP discontinued the evaluation of this
project.
ACTIVITY III, PROJECT 36:
CERAMIC MICROFILTRATION
SYSTEM DEMONSTRATION
Project Overview
The purpose of this project is to evaluate the
performance of the BASX Systems, LLC
Ceramic Microfiltration System (CMS) to
effectively remove copper, iron, manganese, and
zinc from a selected acid mine drainage (AMD).
The project is divided into three phases: bench-
scale scoping tests of two to four pretreatment
technologies to determine those most effective
in precipitating the target metals; 1-gallon per
minute (gpm) pilot-scale testing of these
technologies under field conditions; and
designing a 300-gpm treatment plant.
Table 5 summarizes the heavy metal
contamination problems currently observed at
the Gregory Incline outfall.
Although nickel does not currently exceed the
discharge standard for Clear Creek, it will be
monitored throughout the study because it is
possible that the discharge limit may be lowered
if a full-scale production facility was
implemented. All the metals listed above were
the only regulated heavy metals that can be
quantified in the Gregory Incline AMD.
The AMD from Gregory Incline has been
chosen for this project; however, the results of
this study can be applied to other sites with
similar water quality and heavy metal
contamination,
Technology Description
The CMS consists of two unit operations:
precipitation and solid liquid separation.
Chemical/physical precipitation is not unique in
treating AMD; however, when coupled with the
ceramic microfilter, the BASX CMS has the
potential for both technical and economic
improvement in the overall handling of heavy
metal precipitates. The ceramic microfilter
performs the work of a conventional clarifier.
As shown in Figure 25, slurry from the
precipitation stage is pumped through the
ceramic filter bundle. The pore size of the filters
is such that water can pass through tangentially
(see Figure 26) to the direction of flow; the
precipitate cannot pass through tangentially and
exits the end of the filter as a concentrated metal
stream.
In the bench-scale phase of this project, several
precipitation steps will be tested for their ability
to remove the targeted metals from AMD and
their compatibility with the ceramic microfilter.
These technologies include chemical
precipitation using sodium hydroxide,
magnesium hydroxide, and physical
precipitation by electrocoagulation with
aluminum and carbon electrodes.
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In the pilot-scale phase, the most effective
precipitation step(s) will be tested onsite in
Black Hawk, Colorado, in a continuous 1-gpm
plant. This phase will prove the CSM at a
higher flow rate than the bench-scale tests and
will provide operating parameters for designing
the 300-gpm plant, which is Phase III of the
Project.
Status
Project 36 began in August 2001. Project
planning and issue of a subcontract to BASX
Systems LLC were completed by the end of
fiscal year 2001.
Table 5. Gregory incline water quality contamination.
Parameter Concentration
Cadmium
Copper
Iron
Manganese
Nickel
Zinc
0.012
0.78 (± 0.06)
153 (±3)
30.8 (±0.6)
0.20 (±0.01)
6.9 (± 0.2)
Colorado Standard
for Clear Creek
0.007
0.064
5.4
1.0
0.56
0.74
Figure 25. Ceramic microfilter bundled.
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Figure 26. Cutaway view of ceramic microfilter bundle.
ACTIVITY IV OVERVIEW
The objective of this activity is to develop,
qualify, and screen techniques that show
promise for cost-effective remediation of mine
waste. The most promising and innovative
techniques will undergo bench- or pilot-scale
evaluations and applicability studies to provide
an important first step to full-scale field
demonstrations. Each experiment is assigned as
an approved project with specific goals, budget,
schedule, and principal team members.
ACTIVITY IV, PROJECT 13:
SULFIDE COMPLEXES
FORMED FROM MILL TAILINGS
PROJECT
Project Overview
A general belief is that any metal oxides that are
mobilized in the upper oxidized zone will be
reprecipitated as sulfides in the lower reducing
zones of the tailings. Numerous metal sulfides
exist and may be formed in this reducing zone of
the tailings. These complexes may be mobilized
as the reduction-oxidation (redox) potential
changes within the tailings. In the case of the
Berkeley Pit, if tailings are deposited into the Pit
lake, and the system's redox potential changes
over time, any metal sulfide complexes could be
mobilized and enter the deep aquifer
surrounding the Berkeley Pit. The main goal of
this project was to determine the leachability of
the tailings produced by Montana Resources
during their operation. This research was very
timely since Montana Resources, ARCO, and
the EPA are presently considering depositing the
tailings produced by Montana Resources into the
Berkeley Pit Lake.
Status
The following summarizes the data generated
during this project.
The initial conditions of the components of the
experiment are as follows:
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• Berkeley Pit water: pH2.2, Eh258 mV
(measured), 756 |o,g/L dissolved arsenic, 182
mg/L dissolved copper, 1072 mg/L dissolved
iron, and 8400 mg/L sulfate.
• Unlimed Tailings Slurry: pH 6.9, Eh 12.7
mV (measured), 5.9 |o,g/L dissolved arsenic,
10 |o,g/L dissolved copper, no dissolved iron,
and 1580 mg/L sulfate.
• Limed Tailings Slurry: pH 9.7, Eh 139 mV
(measured), 16.3 |o,g/L dissolved arsenic,
10 |o,g/L dissolved copper, 6.2 |o,g/L dissolved
iron, and 990 mg/L sulfate.
• Distilled Water: pH 9.1, Eh 108 mV
(measured), no dissolved arsenic, 2.4 |o,g/L
dissolved copper, 12.3 |o,g/L dissolved iron,
and no sulfate.
Using a mass balance approach, the total metals
leached out of the tailings material was
determined. Tailings slurry with lime added
deposited in Berkeley Pit water showed a 10%
increase in dissolved copper, an 18% increase in
dissolved iron, a 65% increase in sulfate, and a
16% decrease in dissolved arsenic. Tailings
slurry without lime added deposited in Berkeley
Pit water showed a 2% decrease in dissolved
copper, a 10% increase in dissolved iron, a 30%
increase in sulfate and a 3% decrease in
dissolved arsenic. Unlimed tailings were also
mixed with distilled water; but because of the
low concentrations present, only qualitative
statements can be made. Significant increases in
dissolved copper, iron, and sulfate can be
determined, but the actual percentage of the
increase would not be relevant. The pH of the
limed tailings/Berkeley Pit water mixture ranged
from 4.0 standard units near the top of the
column to 3.7 standard units at the bottom. The
pH of the unlimed tailings/Berkeley Pit water
mixture ranged from 4.5 standard units near the
top of the column to 3.7 standard units at the
bottom. The pH of the unlimed tailings/distilled
water mixture was fairly constant at about 7.0
standard units throughout the column.
The Final report will be completed in FY02.
ACTIVITY IV, PROJECT 14
ARTIFICIAL NEURAL
NETWORKS AS AN ANALYSIS
TOOL FOR GEOCHEMICAL
DATA
Project Overview
The Montana Bureau of Mines and Geology
provided inductively coupled plasma (ICP)
water quality analysis data from the Berkeley Pit
that were used in a neural network approach to
modeling Berkeley Pit water chemistry. The
available Berkeley Pit data comprise a relatively
small data set for neural network analysis and
results, though encouraging, are not reliable for
substantive predictive modeling.
Artificial neural networks comprise a relatively
new approach to modeling complex nonlinear
systems. Due to the inherent structure of neural
networks, they have the desirable characteristics
of being tolerant of noise in data and, more
importantly, of not requiring apriority model for
parameter prediction. Instead, neural networks
learn relationships from data examples.
Neural networks are generally grouped into two
main categories: supervised and unsupervised.
Supervised neural networks use known data
examples consisting of input/desired output pairs
and adjust themselves to learn the relationship
between input/output data. Unsupervised neural
networks use only input data with no known
output pairs. Unsupervised neural networks
work by detecting clusters and trends in the data
with minimal user input. As such, unsupervised
neural networks can provide a powerful,
unbiased approach to data analysis. Both neural
network approaches excel in analyzing large,
complex, multidimensional data sets.
Two neural network approaches were used to
analyze the available Berkeley Pit data. First,
the data matrix was used as input to an
unsupervised neural network to determine if any
previously unidentified data clusters or trends
could be determined. For this sparse data set,
this classification or data-mining approach was
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unsuccessful. Secondly, supervised neural
networks were constructed and trained to
investigate relationships between the various
chemical species, depth, pH, and specific
conductivity. Various testing combinations
were analyzed and results are encouraging to
pursue this approach with a more complete data
set.
Status
Results were not verified with a comprehensive
testing data set; but because they were validated
with small data subsets, indications are that
neural networks can analyze sparse,
geochemical data with good reliability. In each
case, the successful results were repeatable,
which is a good indicator of reliability. More
data is needed, and the intention of this project is
to recommend a good sampling program over
the next few years. If complete data were to be
collected, a neural network could determine data
relationships in a fraction of the time.
The final report will be completed in FY02.
ACTIVITY IV, PROJECT 16
PIT LAKE SYSTEM
CHARACTERIZATION AND
REMEDIATION FOR BERKELEY
PIT—PHASE III
Project Overview
This research project is designed to study and
characterize several aspects of the Berkeley Pit
lake system to gain a better understanding of the
pit lake systems. The information obtained from
the Berkeley Pit lake research will be used to
predict future qualities of the water, to evaluate
the potential for natural remediation, to
determine if partial in-situ remediation may be
practical prior to pump and treat remediation, to
develop new or improved remediation
technologies, and to predict water quality for
similar bodies of water in the United States. The
following areas of research and testing for the
Berkeley Pit lake have been determined: Humic
Remediation Potential; Algal Remediation of
Berkeley Pit Water; Berkeley Pit Aquifer
Modeling; and Remediation by Photocatalysis.
Technology Description
Humic Remediation Potential
Humic substances have widely varying chemical
compositions and molecular weights. These
substances are generally acidic and are
considered to be polymeric in structure. Humic
materials are produced by the biological and
chemical degradation of plant and animal matter
and are often operationally separated into two
water-soluble fractions, fulvic acids, and humic
acids. The distinction between these two groups
is a result of different molecular-weight ranges,
solubilities, and the separation procedure used.
The fulvic acid group has the lower molecular-
weight range and higher water solubility.
Chemical analyses of humic materials has
consistently demonstrated the presence of a
large fraction of aromatic material and
carboxylic acid and phenolic functional groups.
These oxygenated functional groups are
responsible for the strong binding of the humic
materials to mineral surfaces and the binding of
metal ions in aqueous solutions.
Algal Remediation of Berkeley Pit
Water
Ongoing research is beginning to help us
understand the microbial ecology of the
Berkeley Pit Lake System, with ever increasing
information becoming available regarding the
diversity of algae, protistans, fungi, and bacteria
that inhabit this mine waste site. Defining the
baseline community structure has been the first
step not only toward understanding the
interactions of the different groups of organisms
but also toward assessing any improvement in
biodiversity within the biotic community. Now
that this first step has begun, this research will
investigate how some of these extremophiles,
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specifically algae, that have been isolated from
the Berkeley Pit Lake System may be used as a
potential solution for bioremediation. The
primary goal of this study is to determine the
potential utilization of algae for bioremediation
of the Berkeley Pit Lake System.
Berkeley Pit Aquifer Modeling
The water level in the Berkeley pit has risen a
little more than 1 foot per month for the last
several years. There are several sources of
ground-water and a range of ground-water
qualities entering the pit: a) contaminated
groundwater from the underground workings in
the bedrock aquifer west of the pit; b) uncon-
taminated groundwater from the bedrock aquifer
east and southeast of the pit; and c)
contaminated alluvial groundwater from east and
south of the pit. At a water-depth of 850 feet,
the rising water in the pit is presently not in
contact with the alluvial aquifer, but rather,
seepage faces have formed along the rim of the
pit near the bedrock-alluvium contact. The
rising water level in the pit will reach a depth of
about 1,150 feet (100 feet above the bedrock-
alluvial contact) before controls will be
implemented.
Presently, a ground-water divide exists roughly
coincident with Continental Drive between the
Berkeley Pit and the Butte valley. Groundwater
and surface water north of the divide flow into
the pit while groundwater and surface water
south of the divide flow into the Metro Storm
Drain and ultimately into Silver Bow Creek. As
the pit water level rises above the bedrock-
alluvium contact, the ground-water gradient
toward the pit will decrease, possibly shifting
the ground-water divide south of the pit, thereby,
diverting a portion of the groundwater now
flowing into the pit to the Butte valley. This
would manifest itself as an increase in water
levels throughout the residential area south of
the pit and a flow increase in the metro storm
drain.
Remediation by Photocatalysis
Numerous technologies are available for
remediating acid rock drainage. These
technologies include biosorption, mineral/resin
adsorption, chemical precipitation, ion
exchange, freeze crystallization, evaporation,
and a host of others. Several of these
technologies have been tested over the past
decade on Berkeley Pit Lake water. Lime
precipitation became recognized as the U.S.
Environmental Protection Agency's Best-
Determined Available Technology for
remediating the Berkeley Pit water. However,
the conventional process had to be modified to
meet discharge standards regarding pH and
manganese and aluminum concentrations. The
resulting two-stage process required an
intermediate filtration step to remove
precipitates that would redissolve upon
continued lime addition.
In a previous study funded by the Mine Waste
Technology Program, a process was developed
for remediating Berkeley Pit water while
simultaneously recovering the copper and zinc
and producing other marketable products. This
process uses a combination of the technologies
listed above but has a novel approach for using
ultraviolet radiation to meet the objectives. As
indicated, the process uses five stages to
selectively remove various metal constituents in
the water by precipitation. Solid/liquid
separations between the individual stages allows
for the precipitates to be recovered and
eventually marketed. Furthermore, the process
also meets the discharge requirements of the
metals including that of arsenic.
Status
Humic Remediation Potential
The results from the experiments demonstrated
that organic amendments can have a positive
effect on the remediation of the water in the
Berkeley Pit. Of the four organic amendments
tested (sawdust, aspen leaves, lawn clippings,
and treated sewage sludge), the treated sewage
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sludge was the most effective at removing the
high concentration metal ions from the water
and raising the pH of the acidic water. The
experimental variables of light versus dark and
readily available room air versus exclusion of
room air had minimal differences in the
sequestering of most metals. Iron was the major
exception to this observation.
Algal Remediation of Berkeley Pit
Water
In general, Chromulina freiburgensis did not
remove metals over a long-term experiment
through absorption or adsorption from Berkeley
Pit water. Removal was not observed for
aluminum, cadmium, chromium, copper,
magnesium, manganese, sulfur, and zinc.
Significant removal was detected for calcium
(12.8%), iron (12.7%), nickel (8.4%), and
silicon (56.2%).
Metal removal was not observed, possibly
because of the long experimentation time of 90
days. In this time, cultures of Chromulina
freiburgensis could have become nutrient
starved and formed cysts. It is possible that the
metals were adsorbed initially, and rereleased
when the cells became stressed. Further
discussion is provided in the final report.
Berkeley Pit Aquifer Modeling
Since water-level data for the alluvial wells and
the Berkeley Pit continue to be collected, it is
possible to continue the calibration process for
several years. In 1995, water levels in the
alluvial aquifer south of the pit had increased by
1 to 3 feet compared to 1991 water levels; by
1998, water-level rise ranged from 5 to 9 feet
compared to 1991 data. In addition to the
continued water-level rise in the pit, this period
coincides with greater-than-normal precipitation
in the area. Thus, calibration in the strictest
sense becomes ambiguous: the relative
contribution of the pit water-level rise and the
increased recharge cannot be determined.
Through modeling, however, the increased
recharge can be eliminated; modeling can
demonstrate if the pit is contributing to the
water-level change in the alluvium.
Remediation by Photocatalysis
In summary, iron removal (Stage I) was
successful and fairly selective with ultraviolet
photo-oxidation in the presence of hydrogen
peroxide; was best under high oxidation
conditions with 254-nm radiation within the 2-
hour time examined; and was essential in this
photochemical treatment process (as noted in
most other industrial selective-metal recovery
processes).
Removal of arsenic (Stage I) was successful and
principally followed the ANSTO UV-Process.
Manganese removal could be accomplished with
photo-oxidation but requires further research to
prove. In this regard, it had to be accomplished
by permanganate addition resulting in Stage
Two. Because permanganate can increase
manganese concentrations, other oxidants should
be tested. Sulfide precipitation of copper (Stage
III) and cadmium (Stage IV) were successful.
Zinc removal (Stage IV) appeared to follow
wurtzite solubility; thus, ZnS precipitation did
not meet the drinking water standard. However,
sphalerite seeding of the stage could prove
worthy and needs further study. Aluminum
precipitation (Stage V) as a hydroxide also
nearly met the drinking water standard and could
feasibly benefit from seeding as well.
Based on the results and discussions of this
study, it is clear that the manganese, zinc, and
aluminum removal stages could be improved.
As discussed previously, this may simply
involve seeding the zinc and aluminum
precipitation stages with more stable solids or
studying further the manganese photo-oxidation
process. Of course, other possibilities could be
explored and may involve kinetics and
temperature effects. Likewise, all stages in the
selective metal recovery process could be
improved kinetically, thermally, and/or
chemically by using better compounds.
The final report will be completed in FY02.
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ACTIVITY IV, PROJECT 17:
MINE DUMP RECLAMATION
USING TICKLE GRASS
PROJECT
Project Overview
Experiments were conducted to test the
reclamation potential of tickle grass in the
greenhouse at Montana Tech and on three
reciprocal transplant sites with the hypothesis
that the Badger Mine (BM) tickle grass
population is an ecotype within the species
suitable for the reclamation of mine dump
materials. Agrostis hiemalis, tickle grass, grows
on the dump consisting of acid generating rock
and tailings formed about 25 years ago. Tests
indicate that this site has a pH of 3.1, and the
soil material has high concentrations of heavy
metals such as arsenic, copper, iron, lead, nickel,
and zinc. The area is located near the Badger
Mine site, northeast of Walkerville in Silver
Bow County, Montana.
The performance of the BM tickle grass
population was compared to populations of
tickle grass from the Beaver Pond (BP) site and
Yellowstone National Park (YN) growing at the
Bridger Plant Material Center in Bridger,
Montana. Data analysis was conducted for
height, basal area, biomass, vigor, plant
appearance, and state of the flower head to
determine whether BM tickle grass population is
an ecotype adapted to harsh conditions.
Status
The results of height and basal area from the
greenhouse study partially validated the
hypothesis of the BM tickle grass population
being an ecotype within the species, where as
the hypothesis of the BM tickle grass population
being more suitable to the mine dump material
was not completely satisfied. The results of the
transplant garden study partially supported the
hypothesis of the BM tickle grass population
being suitable for the reclamation of mine dump
material as compared to the BP and the YN
population. Soil characterization of the Badger
Mine dump material verified the assumption of
the BM tickle grass population surviving harsh
conditions of low pH, low nutrient levels, and
high concentrations of heavy metals such as
arsenic, copper, iron, lead, nickel, and zinc. An
on-site reclamation option was favored for the
Badger Mine site.
The final report will be completed in FY02.
ACTIVITY IV, PROJECT 18:
INVESTIGATION OF NATURAL
WETLANDS NEAR
ABANDONED MINE SITES
Project Overview
The main objective of this project was to
determine how and to what extent metals are
being attenuated by natural wetlands at two
remote locations in Montana. Sites selected for
fieldwork included the Copper Gulch wetland
(near Jefferson City, Montana), and the Fisher
Creek wetland (near Cooke City, Montana). At
both sites, representative samples of soil,
groundwater, and surface water were collected
for metal analysis. The hydrogeology of each
wetland was characterized, with the help of
shallow piezometers to monitor water level and
to collect groundwater samples. Each site was
visited several times throughout the year to
determine seasonal changes in hydrology or
metal removal efficiency.
Status
At Copper Gulch, discharging groundwater
initially had low pH (3.5 to 4) and elevated
concentrations of metals, including aluminum,
iron, copper, manganese, and zinc. By the time
water reached the outlet of the sedge wetland,
pH rose to > 5, and concentrations of aluminum,
iron, and copper were decreased. Most of the
copper appeared to be scavenged by the
subsurface wetland soils; whereas, aluminum
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and iron were precipitated within the surface
drainage of the wetland. At Fisher Creek,
influent springs were weakly acidic, very dilute,
but contained elevated copper concentrations.
Although a quantitative water and copper mass
balance was not possible, it appeared that most
of the influent copper passed through or around
the wetland, with only localized attenuation.
Nonetheless, copper concentrations in humic
wetland soils at this site were extremely high
(> 1 wt %), indicating that metal removal,
although inefficient, can result in impressive
accumulations over very long periods of time.
If natural wetlands are to be used for treating
metals or acidity near abandoned mine sites,
steps should be taken to create the largest water
retention time possible, which may entail
enlarging a preexisting wetland or eliminating
channeled flow. The potential for metal-rich
wetlands to become a source, rather than a sink,
for contaminants should also be considered.
The final report will be completed in FY02.
ACTIVITY IV, PROJECT 19:
REMOVING OXYANIONS OF
ARSENIC AND SELENIUM
FROM MINE WASTEWATERS
USING GALVANICALLY
ENHANCED CEMENTATION
TECHNOLOGY
Project Overview
Many solution species can be effectively
removed from mine water by electrochemical
reduction of the aqueous species, to a solid
elemental species on the surface of a metal
(called cementation), e.g., aqueous solution
species of copper, arsenic, selenium can be
reduced to the solid elemental state on an iron
surface. Presently, the industrial use of
cementation has been limited to copper
recovery. It was proposed that the rate of
reduction of arsenic (arsenate, arsenite) and
selenium (selenate, selenite) could be increased
dramatically by using galvanically coupled
substrates (instead of iron).
Galvanically coupled substrates provide greatly
enhanced active metal dissolution rates. The
enhanced metal dissolution rates (called anodic
dissolution) are accompanied by the production
of electrons in the substrate (iron). The
available electrons in the substrate metal (iron)
must be discharged at cathodic sites on the more
noble metal surface. The consumption of
electrons is characterized as reduction reactions,
i.e., reduction of aqueous species in the solution
phase to the elemental state on the nobler
cathodic surface. Therefore, if the metal
dissolution rate is enhanced (increased) then the
reduction rate of oxyanions (arsenic and
selenium) will also be increased.
Two major experimental studies were conducted
during the present investigation, i.e.,
electrochemical characterization of iron and
galvanic couple surfaces and application of iron
and galvanic couples for selenium/arsenic
removal from synthetic and real solutions. The
conclusions drawn from each of the major
studies are briefly presented below.
Status
Electrochemical Characteristics of Iron and
Galvanic Couple Surfaces
Selenate. The conclusions drawn from the
electrochemical studies included:
• The selenate reduction reaction proceeded
rapidly on an iron substrate.
• The selenate reduction reaction rate was
enhanced by using galvanically coupling.
Coupling of iron with copper approximately
doubles the selenate reduction rate (for equal
surface areas of iron and copper in the
presence of 2 mg/L selenium at pH 7).
Coupling of iron with nickel increased the
selenate reduction rate by a factor of
approximately 25 (for equal surface areas of
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iron and nickel in the presence of 2 mg/L
selenium atpH 7).
• If the electrochemically-measured rates are
applied to a kettle reactor environment, it is
predicted that selenate removal could be
accomplished very rapidly.
Ar sen ate. The conclusions drawn from the
electrochemical studies included:
• The arsenate reduction reaction proceeded
rapidly on an iron substrate.
• The hydrogen ion reduction reaction rate was
increased by using galvanically coupling.
Coupling of iron with copper increased the
hydrogen ion reduction rate by a factor of 18
times (for equal surface areas of iron and
copper at pH~7).
• The effect of the presence of arsenate in the
iron/copper/arsenic system was to decrease
the rate of the hydrogen ion reduction
reaction. This effect was opposite to the
effect of the presence of arsenate in the
iron/arsenic system, e.g., the presence of
arsenate in the iron/arsenic system increased
the overall rate. The reasons for the noted
effect are presently unknown.
• Insufficient data were generated to make a
final conclusion concerning the effect of
galvanic coupling on arsenate removal. It is
recommended that further studies be
conducted to evaluate the use of other
couples, such as iron/nickel, iron/palladium,
and magnesium/aluminum couples.
Application of Iron and Galvanic Couples
for Selenium/Arsenic Removal
Kettle Reactor Test Work. The conclusions
drawn from the kettle treatment test work using
synthetic water and industrial water included:
• Iron particulate was an excellent
reductant for reducing selenate or
arsenate. The same result was achieved
in synthetic water and industrial water,
except a lower pH was required for the
industrial water.
• Iron/copper galvanic couples showed mixed
results but in all cases the enhancement by
the galvanic couple, where it occurred, was
not very significant.
• The rate of arsenic and selenium removal at a
nominal pH of 4 showed the same general
trend for the various substrates, i.e., the rate
of removal of arsenic and selenium was
greater for the uncoupled iron than for the
iron/copper galvanic couples. At higher
copper contents, the arsenic and selenium
removal rate decreased.
• The electrochemical study results suggest
that galvanic couples should show a major
enhancement in the selenate reduction rate.
The kettle test results showed relatively poor
enhancement by the iron/copper galvanic
couples compared to uncoupled iron for both
arsenate and selenate.
The final report will be completed in FY02.
ACTIVITY IV, PROJECT 20:
ALGAL BIOREMEDIATION OF
BERKELEY PIT WATER,
PHASE II
Project Overview
The Berkeley Pit Lake System is one of the
largest contaminated sites in North America and
is located near the headwaters of the largest
superfund site in the United States. The Pit
Lake is more than 542 meters deep with a lateral
extent of approximately 1.8 by 1.4 kilometers
across the rim. The only larger pit mine in the
United States is the Bingham Pit in Salt Lake
City, Utah. The Berkeley Pit has a water depth
of approximately 275 meters and is rising at a
rate of about 8 meters per year. This represents
roughly 1,140 billion liters of metal laden,
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contaminated water, with a pH of 2.7, that has
been designated a Superfund project for cleanup.
The goal of the Mine Waste Technology
Program, Activity IV Project, was to continue to
gain an understanding of the microbial ecology
of the Berkeley Pit Lake System, which will
ultimately provide necessary data for
bioremediation studies that may apply to other
contaminated pit lakes worldwide.
Status
Preliminary lab experiments showed that even
getting algae to grow to very eutrophic levels
did not significantly remove metals from the
water. The only metal that was significantly
removed was aluminum, and the final
concentration of aluminum under optimal
removal in the experiments was 150 mg/L.
Furthermore, under optimal experimental metal
removal, the pit water still contained high levels
of metals and would need to be treated with lime
precipitation as stated in the record of decision.
Since the solubility product of A1(OH)3 is 3.8 X
10~9 compared to the solubility product of
Cu(OH)2 of 3.5 X 10"7, the aluminum would
precipitate before the copper. Therefore,
aluminum removal by the algae would not
significantly reduce the treatment cost for
Berkeley Pit water or significantly reduce the
amount of sludge generated.
The final report will be completed in FY02.
ACTIVITY V OVERVIEW
TECHNOLOGY TRANSFER
This activity consists of making technical
information developed during Mine Waste
Technology Program (MWTP) activities
available to industry, academia, and government
agencies. Tasks include preparing and
distributing MWTP reports, presenting
information about MWTP to various groups,
publications in journals and magazines, holding
Technical Integration Committee meetings,
sponsoring mine waste conferences, and
working to commercialize treatment
technologies.
Fiscal Year Highlights
• The MWTP Annual Report was published
summarizing fiscal year accomplishments. A
similar report will be published each year.
• Several MWTP professionals appeared at
varied meetings to discuss the Program with
interested parties. Many mine waste
conferences, as well as mining industry
meetings, were attended.
ACTIVITY VI OVERVIEW
TRAINING AND EDUCATION
Through its education and training programs, the
Mine Waste Technology Program (MWTP)
continues to educate professionals and the
general public about the latest information
regarding mine and mineral waste cleanup
methods and research.
As a result of rapid technology and regulatory
changes, professionals working in the mine- and
mineral-waste areas often encounter difficulties
in upgrading their knowledge and skills in these
fields. In recent years, the environmental issues
related to the mining and mineral industries have
received widespread public, industry, and
political attention. While knowledge of current
research and technology is vital for dealing with
mine and mineral wastes, time and costs may
prevent companies from sending employees
back to the college classroom.
Through short courses, workshops, conferences,
and video outreach, Activity VI of MWTP
educates professionals and the general public
and brings the specific information being
generated by bench-scale research and pilot-
scale technologies to those who work in mine-
and mineral-waste remediation.
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Fiscal 2001 Highlights
• The Mine Design, Operations, and Closure
Conference 2001, conducted in April 2001
continued last year's interagency cooperation.
The 5-day event was cosponsored by the U.S.
Forest Service; U.S. Bureau of Land
Management; Montana Department of State
Lands; MSB Technology Applications, Inc.;
Haskell Environmental Research Studies
Center; several other private companies; and
Montana Tech. During the conference,
experts presented overviews on such topics as
predictive chemical modeling for acid mine
drainage, mine water quality source control,
state-of-the-art containment technologies, and
innovative pit reclamation. Over 130 mine
operators, consultants, and professionals from
the private and public sectors attended the
conference.
• The Mine and Mineral Waste Emphasis
Program has an enrollment of 10 students
with all of them receiving funding from
MWTP. This is an interdisciplinary graduate
program that allows students to major in their
choice of a wide variety of technical
disciplines while maintaining an emphasis in
mining and mineral waste.
• A group of Mine and Mineral Waste
Emphasis graduate students attended the
Mine Design, Operations, and Closure
Conference 2001.
• A cooperative agreement is in place for work
with the Haskell Environmental Research
Studies Center at Haskell Indian Nations
University.
Graduate students in the Mine and Mineral
Waste Emphasis Program are working on
projects in Activities IV.
As part of the Native American Initiative,
Montana Tech presented five short courses:
Mining and the Environment at Fort Belknap,
and Acid Rock Drainage at both Fort
Belknap and Salish Kootenai College. An
environmental learning community was set
up to house the short courses and Web
courses to make them accessible to Native
American communities around the country.
One Web course, Environmental Planning
for Small Communities, is on-line.
Future Activities
The following training and educational activities
are scheduled for 2002:
• MWTP Training and Educational activities
will offer the Mine Design, Operations, and
Closure Conference 2002 in April 2002.
• MWTP is working on a cooperative
education package for the Montana
Department of Environmental Quality.
• All funded Mine and Mineral Waste
Emphasis Program graduate students will
work on mine waste-oriented projects as a
part of their funding requirements.
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FINANCIAL SUMMARY
Total expenditures during the period October 1,
2000, through September 30, 2001, were
$3,687,532, including both labor and nonlabor
expense categories. Individual activity accounts
are depicted on the performance graph in
Figure 27.
$4,000,000 -,
$3,000,000 -
$2,000,000 -
$1,000,000 -
$0
MWTP
Mine Waste Technology Program
FY-2002 Cost Per Activity
Activity I
Activity I
Activity I
Activity IV
Activity V
Activity VI
General
Support
^FY-2002 Costs $3,687,532 $256,821 $1,701 $2,117,062 $194,776 $219,925 $226,951 $670,294
Figure 27. Mine Waste Technology Program fiscal 2001 performance graph, costs per activity.
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COMPLETED ACTIVITIES
For information on the following completed Mine Waste Technology Program activities, refer to the web
site: http://www.epa.gov/ORD/NRMRL/std/mtb/mwtphome.html.
Activity III
Project 1
Project 2
Project 4
Project 5
Project 6
Project 7
Project 9
Project 10
Project 11
Project 12A
Project 13
Project 17
Project 18
Project 20
Activity IV
Project 1
Project 2
Project 3
Project 3A
Project 3B
Project 4
Project 5
Project 7
Project 8
Project 9
Project 10
Project 11
Project 12
Remote Mine Site Demonstration
Clay-Based Grouting Demonstration
Nitrate Removal Demonstration
Biocyanide Demonstration
Pollutant Magnet
Arsenic Oxidation
Arsenic Removal
Surface Waste Piles—Source Control
Cyanide Heap Biological Detoxification Demonstration
Calliope Mine Internet Monitoring System
Hydrostatic Bulkhead with Sulfate-Reducing Bacteria
Lead Abatement Demonstration
Gas-Fed Sulfate-Reducing Bacteria Berkeley Pit Water Treatment
Selenium Removal/Treatment Alternatives
Berkeley Pit Water Treatment
Sludge Stabilization
Photoassisted Electron Transfer Reactions Research
Photoassisted Electron Transfer Reactions for Metal-Complexed Cyanide
Photoassisted Electron Transfer Reactions for Berkeley Pit Water
Metal Ion Removal from Acid Mine Wastewaters by Neutral Chelating Polymers
Removal of Arsenic as Storable Stable Precipitates
Berkeley Pit Innovative Technologies Project
Pit Lake System—Characterization and Remediation for the Berkeley Pit
Pit Lake System—Deep Water Sediment/Pore Water Characterization and Interactions
Pit Lake System—Biological Survey of Berkeley Pit Water
Pit Lake System Characterization and Remediation for Berkeley Pit—Phase II
An Investigation to Develop a Technology for Removing Thallium from Mine
Wastewaters
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KEY CONTACTS
U.S. Environmental Protection Agency:
Roger C. Wilmoth
U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research
Laboratory
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Telephone: (513)569-7509
Fax: (513)569-7471
wilmoth.roger@epa.gov
U.S. Department of Energy:
Madhav Ghate
U.S. Department of Energy
National Energy Technology Laboratory
P.O. Box 880
3610 Collins Ferry Road
Morgantown, WV 26507-0880
Telephone: (304) 285-4638
Fax: (304)285-4135
mghate@netl.doe.gov
MSE Technology Applications, Inc.
Jeff LeFever, Program Manager
MSE Technology Applications, Inc.
P.O. Box 4078
Butte, MT 59702
Telephone: (406) 494-7358
Fax: (406)494-7230
jlefever@mse-ta.com
Montana Tech:
Karl E. Burgher, Montana Tech MWTP
Project Manager
Montana Tech of the University of Montana
1300 West Park Street
Butte, MT 59701-8997
Telephone: (406)496-4311
Fax: (406)496-4116
kburgher@mtech.edu
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Printed on recycled paper with soybean ink
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