EPA/600/R-09/160
September 2008
Mine Waste Technology Program
Activity III, Project 42
Physical Solutions for Acid Rock Drainage at
Remote Sites Demonstration Project
By:
Jay McCloskey and Randy Hiebert
MSB Technology Applications, Inc.
Mike Mansfield Advanced Technology Center
Butte, Montana 59702
Under Contract No. DE-AC09-96EW96405
Through EPA IAG No. DW89-92178601-0
Diana Bless, EPA Project Officer
Systems Analysis Branch
National Risk Management Research Laboratory
Cincinnati, Ohio 45268
This study was conducted in cooperation with
U.S. Department of Energy
Environmental Management Consolidated Business Center
Cincinnati, Ohio 45202
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Disclaimer
This publication is a report of work conducted under the Mine Waste Technology Program that was
funded by the Environmental Protection Agency and managed by the Department of Energy under the
authority of an Interagency Agreement.
Because the Mine Waste Technology Program participated in EPA's Quality Assurance Program, the
project plans, laboratory sampling and analyses, and final report of all projects were reviewed to ensure
adherence to the data quality objectives. The views expressed in this document are solely those of the
performing organization. The views and opinions of authors expressed herein do not necessarily state or
reflect those of the United States Government or any agency thereof
Reference herein to any specific commercial product, process, or service by trade name, trademark,
manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or
favoring by the United States Government or any agency thereof or its contractors or subcontractors.
Neither the United States Government nor any agency thereof, nor any of their employees, nor any of
their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes
any legal liability or responsibility for the accuracy, completeness, or any third party's use or the results
of such use of any information, apparatus, product, or process disclosed, or represents that its use would
not infringe privately owned rights.
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation's
land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to
formulate and implement actions leading to a compatible balance between human activities and the ability
of natural systems to support and nurture life. To meet this mandate, EPA's research program is
providing data and technical support for solving environmental problems today and building a science
knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect
our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for investigation
of technological and management approaches for preventing and reducing risks from pollution that
threaten human health and the environment. The focus of the Laboratory's research program is on
methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and
subsurface resources; protection of water quality in public water systems; remediation of contaminated
sites, sediments and ground water; prevention and control of indoor air pollution; and restoration of
ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies that
reduce the cost of compliance and to anticipate emerging problems. NRMRL's research provides
solutions to environmental problems by: developing and promoting technologies that protect and improve
the environment; advancing scientific and engineering information to support regulatory and policy
decisions; and providing the technical support and information transfer to ensure implementation of
environmental regulations and strategies at the national, state, and community levels.
This project was conducted under the Mine Waste Technology Program. It was funded by the U.S. EPA
and administered by the U.S. Department of Energy in cooperation with various offices and laboratories
of the DOE and its contractors. It is made available at www.epa.gov/minewastetechnology by EPA's
Office of Research and Development to assist the user community and to link potential users with the
researchers.
Sally Gutierrez, Director
National Risk Management Research Laboratory
in
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Abstract
This report summarizes the results of Mine Waste Technology Program, Activity III, Project 42, Physical
Solutions for Acid Rock Drainage at Remote Sites, funded by the U.S. Environmental Protection Agency
(EPA) and jointly administered by EPA and the U.S. Department of Energy.
Acid rock drainage (ARD) is a serious environmental problem facing many inactive and active mine sites
throughout the United States. The ARD from the Susie Mine in Rimini, Montana has a high ratio of iron
to other metals, which means that conventional treatment technologies have limited applicability. MSE
Technology Applications, Inc.'s Reductive Precipitation Process, a two-stage iron precipitation/filtration
process with a polishing step to remove arsenic, is designed to treat high-iron ARD. Following successful
laboratory treatability tests, the process was implemented at the Susie Mine, with an emphasis on zinc and
arsenic removal. While zinc was effectively removed and the level of arsenic substantially reduced, the
field system was never able to achieve arsenic levels below 10 micrograms per liter (jig/L). The lowest
arsenic level measured in the treated effluent was 51.9 (ig/L on October 3, 2006. Reasons for less-than-
ideal arsenic removal include: numerous process upsets, a shortened schedule with minimal process
optimization, and elimination of the polishing step. The process had mixed results, but was generally
effective for the removal of cadmium, copper, lead, iron, and manganese. The primary recommendation
from the field study was to continue to operate and maintain the Reductive Precipitation Process. Further
process optimization and implementation of a polishing step for arsenic removal were also recommended.
IV
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Contents
Page
Disclaimer ii
Foreword iii
Abstract iv
Contents v
Figures vi
Tables vi
Acronyms and Abbreviations vii
Acknowledgments viii
Executive Summary ES-1
1. PROJECT DESCRIPTION 1
1.1 Background 1
1.2 General Information 2
1.2.1 Acid Rock Drainage Chemistry Overview 2
1.2.2 Geochemistry Review 3
1.3 Project Objectives 4
1.4 Site Description 5
1.5 Experimental Design 5
1.5.1 Sampling Locations 5
1.5.2 Field Measurements 5
1.6 Technology Description and Design 5
1.6.1 Technology Description 5
1.6.2 Technology Design 6
1.6.3 Technology Construction 6
1.6.4 Documentation 7
1.6.5 Assessment and Response 7
1.6.6 System Verification and Acceptance 7
1.6.7 Process Flow Description 8
2. RESULTS AND DISCUSSION 14
2.1 Treatability Study Results 14
2.2 Field Demonstration Results 14
2.2.1 Arsenic 14
2.2.2 Cadmium 15
2.2.3 Copper 15
2.2.4 Iron 15
2.2.5 Lead 15
2.2.6 Manganese 15
2.2.7 Zinc 15
2.2.8 Sludge 16
2.3 Contaminant Reduction Calculations 16
2.4 Technology Costs and Process Economics 16
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Contents (Cont'd)
Page
3. CONCLUSIONS AND RECOMMENDATIONS 20
4. REFERENCES 21
Appendix A: Technical Review Meeting - Phase I, Attendance Sheet A-
Appendix B: Historical Data for Susie Mine Discharge B-
Appendix C: Reductive Precipitation Process Diagrams C-
AppendixD: Simulation Model for Reductive Precipitation Process D-
AppendixE: Independent Technical Review, Attendance Sheet E-
Appendix F: Summary of Quality Assurance Activities F-
Figures
1-1. Iron speciation diagram for Susie/Valley Forge Mine water 10
1-2. Site map 10
1-3. Susie Mine Reductive Precipitation Process equipment layout 11
2-1. Total arsenic values of Reductive Precipitation Process 17
Tables
1-1. Susie Mine Contaminant Concentrations and Regulatory Standards 12
1-2. Analytical Information for the Susie Mine Waters 12
1-3. Sample Locations 13
1-4. Laboratory Analyses and Field Measurements 13
2-1. Bench-Scale Tests - Standards, Feed Concentrations, and Effluent Levels 17
2-2. Field Test- Standards, Feed Concentrations, Effluent Levels, and MDLs 18
2-3. Effluent Data 18
2-4. Contaminant Loading Reduction to Tenmile Creek 18
2-5. Estimated Annual Reagent Costs 19
2-6. Water Model Capital Cost Breakdown 19
2-7. Annual Operational CostEstimate 19
2-8. Annual Disposal Cost for Solid Waste Material 19
VI
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Acronyms and Abbreviations
Al
ARD
As
As(III)
As(V)
Ca
Ca(OH)2
Cd
COM
Cu
DOE
EPA
EXAFS
Fe
GFH
H&S
ITR
MCL
MDEQ
MDL
Mg
Mn
MSB
MWTP
NaOH
NRMRL
O&M
ORP
P&ID
Pb
QA
QAPP
RACs
RPD
Se
Susie
TCLP
TSS
Zn
ZVI
aluminum
acid rock drainage
arsenic
arsenite
arsenate
calcium
calcium hydroxide or hydrated lime
cadmium
CDM Federal Programs Corporation
copper
U.S. Department of Energy
U.S. Environmental Protection Agency
extended x-ray absorption fine structure
iron
granular ferric hydroxide
health and safety
independent technical review
maximum contaminant level
Montana Department of Environmental Quality
method detection limit
magnesium
manganese
MSE Technology Applications, Inc.
Mine Waste Technology Program
sodium hydroxide
National Risk Management Research Laboratory
operating and maintenance
oxidation-reduction potential
piping and instrumentation diagram
lead
quality assurance
quality assurance project plan
Remedial Action Contracts
relative percent difference
selenium
Susie/Valley Forge Mine
toxicity characteristic leaching procedure
total suspended solids
zinc
zero valent iron
vn
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Acknowledgments
This document was prepared by MSB Technology Applications, Inc. (MSB) for the U.S. Environmental
Protection Agency's (EPA) Mine Waste Technology Program (MWTP) and the U.S. Department of
Energy's (DOE) Environmental Management Consolidated Business Center. Ms. Diana Bless was EPA's
MWTP Project Officer while Mr. Gene Ashby was DOE's Technical Program Officer. Ms. Helen Joyce
was MSB's MWTP Program Manager. Mr. Jay McCloskey was MSB's MWTP Project Manager.
Other individuals that supported the project and development of this document are listed below.
Mike Bishop, EPA Region 8
Keith Large, Montana Department of Environmental Quality (MDEQ)
Vic Anderson, MDEQ
Neil Marsh, COM Federal Programs Corporation (COM)
David Swanson, COM
Mark Poore, Rimini Land Owner (Rimini)
Roger James, Rimini
Dr. Larry Twidwell, Montana Tech
Joe Ruschetti, MSE
Randy Hiebert, MSE
Michelle Lee, MSE
Dave Sheldon, MSE
Roland Rees, MSE
Larry Beagley, MSE
Miriam King, MSE
Vlll
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Executive Summary
Acid rock drainage (ARD) is a serious environmental problem facing many inactive, abandoned, and
active mine sites throughout the United States. ARD is produced when metal-sulfide minerals,
particularly pyrite (FeS2), come in contact with oxygen and water. This reaction results in increased
acidity of the water and increased toxic metal mobility.
The ARD from the Susie Mine in Rimini, Montana has a high ratio of iron to other metals, which means
that conventional treatment technologies have limited applicability. This is due to difficulties associated
with high particulate loadings, elevated total suspended solids, and high concentrations of total dissolved
solids. Therefore, it was postulated that adsorption of the heavy metals onto ferrihydrite and co-
precipitation followed by solid/liquid separation would be an effective treatment process. An added
benefit was to use the physical characteristics of the Susie Mine to enhance the overall efficiency of the
proposed treatment process.
MSB Technology Applications, Inc.'s (MSB) Reductive Precipitation Process is designed to remove
arsenic and heavy metals from high-iron ARD similar to that from the Susie Mine. The process is
normally a two-stage iron precipitation/filtration process with a polishing step to remove trace quantities
of arsenic resulting in two environmentally stable products. Ferrous iron is added to remove dissolved
arsenic as an insoluble ferrous arsenate salt. The remaining dissolved arsenic is removed by adsorption
on ferric oxide (ferrihydrite) when the ferrous ions are oxidized to ferric and ferrihydrite is precipitated.
The ferrous arsenate and ferrihydrite solids are combined in the process and removed by conventional
settling/flocculation and pressure filtration prior to disposal.
Initially, laboratory treatability tests were performed to test the Reductive Precipitation Process on waters
from various mines, including the Susie. Process optimization was performed in the lab to save time in
the field and to achieve arsenic and metals removal to levels below Circular WQB-7, Montana Numeric
Water Quality Standards. Data collected during these tests indicated that all contaminants, with the
exception of manganese, could be consistently reduced below the WQB-7 standards.
Following successful laboratory treatability tests, the process was implemented at the Susie Mine, with an
emphasis on zinc and arsenic removal. While zinc was effectively removed and the level of arsenic was
reduced more than 99.8%, the field system was never able to achieve arsenic levels below the WQB-7
action level of 10 micrograms per liter (|ig/L). The lowest arsenic level measured in the treated effluent
was 51.9 (ig/L on October 3, 2006. Reasons for less-than-ideal arsenic removal included: numerous
process upsets, a shortened schedule with minimal process optimization, and elimination of the polishing
step. The process had mixed results, but it was generally effective for removal of cadmium, copper, lead,
iron, and manganese.
The primary recommendation from this field study was the continued operation and maintenance of the
Reductive Precipitation Process implemented by the MWTP at the Susie Mine. While the treatment
process did not achieve all the WQB-7 action level standards, it continues to remove a substantial
quantity of contamination from the mine effluent. It is also recommended that the process be optimized
further and that a polishing step be implemented to remove arsenic to WQB-7 action level standards.
EPA Region 8 plans to run the current process for an additional six months to one year and share data
with the MWTP. To further improve the treatment process, enhanced settlers were recommended to
separate the solid particles from the liquid. The slow settling time in the field turned out to be the primary
bottleneck in the system, reducing the flow at times, and preventing process optimization.
ES-1
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1. Project Description
1.1 Background
This document is the final report for the Mine
Waste Technology Program (MWTP), Activity III,
Project 42, Physical Solutions for Acid Rock
Drainage at Remote Mine Sites Demonstration
Project (Physical Solutions Project). This final
report provides information on the work
completed and the findings by MSB Technology
Applications, Inc. (MSB) and contract personnel
during the execution of the field demonstration at
the Susie Mine during late 2006 and early 2007.
The Phase I scope of work (laboratory treatability
testing) was completed in March 2006 and the
findings are summarized in the Interim Report for
the Physical Solutions Project (MSB, 2006). This
report references those tests but deals primarily
with results obtained during the field
demonstration at the Susie Mine.
This project was funded by the U.S.
Environmental Protection Agency (EPA) and
jointly administered by EPA and the U.S.
Department of Energy (DOE) through an
Interagency Agreement. This project was selected
for demonstration from several potential projects
presented by MSE, private industry, and EPA
regional offices at the Technical Integration
Committee Meeting for the MWTP in April 2002.
Representatives from the Montana Department of
Environmental Quality (MDEQ) Environmental
Management Bureau and Mine Waste Cleanup
Bureau, EPA Region 8, COM Federal Programs
Corporation (COM), and MSE met in Helena,
Montana on March 26, 2003. The purpose of the
meeting was to discuss options for source control
and reduction of metals loading from acid rock
drainage (ARD) to the Tenmile Creek in the
Rimini Mining District, approximately 15 miles
west of Helena, Montana. The Upper Tenmile
Creek Mining Area Site Remedial Design Acid
Mine Drainage Study (COM, 2003), prepared by
COM for EPA in consultation with the MDEQ,
was discussed. This report highlighted 17 mine
discharges that contribute to metal loadings in
Tenmile Creek. The project and how it could
support sustainable remediation efforts for the
Tenmile Creek drainage were also discussed.
Representatives from both the MDEQ and EPA
Region 8 requested that the MWTP perform
treatability studies on three of the 17 mine waters
to determine viable treatment options. These three
metal-laden mine waters, which contribute over
65% of the metals loading, are the Susie /Valley
Forge (Susie), Lee Mountain, and Red Water mine
effluents. Laboratory treatability studies were
proposed for the three mine waters individually
and a combination of all three. MDEQ had been
approached previously by the Corps of Engineers
with the concept of collecting these metal-laden
mine waters prior to entering Tenmile Creek and
treating them in a single treatment system.
On June 2, 2004, MSE presented preliminary
treatability test results to the EPA National Risk
Management Research Laboratory (NRMRL)
Project Officer, representatives from the MDEQ,
EPA Region 8, and COM. (Appendix A provides
a list of the attendees.) During this meeting, the
Susie Mine was selected as the site for the MWTP
field demonstration. The criteria used to select the
Susie Mine were: 1) significance to the Tenmile
Creek Drainage EPA Record of Decision to
determine alternative treatment for ARD; 2)
accessibility to the mine site; 3) opportunity for
sustainable treatment of the water; and 4)
compatibility with future plans (i.e., EPA Region 8
and MDEQ) to treat the water and/or identify
source control options in the mine workings. Final
results from the treatability studies or Phase I of
the Physical Solutions Project are summarized in
the document entitled Interim Report - Physical
Solutions for Acid Mine Drainage at Remote Sites
Demonstration Project, Phase I (MSE, 2006).
Following treatability tests, the Reductive
Precipitation Process was determined to be the
most effective process scenario to treat the Susie
Mine water. This process consists of pH
adjustment using sodium hydroxide (NaOH) or
hydrated lime [Ca(OH)2], combined with
adsorption of metals onto ferric hydroxide
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precipitate followed by a polishing step using
granular ferric hydroxide (GFH) or zero valent
iron (ZVI).
Representatives from EPA Region 8, CDM,
MDEQ, ASARCO, and Montana Tech performed
technical reviews of the draft interim report in
which their comments and recommendations were
incorporated into the final version. There was an
overwhelming consensus in the technical reviews
that the proposed treatment process should be able
to effectively treat the Susie Mine water and
should be tested at the pilot-scale. EPA Region 8
supported the project by opening the Susie Mine
adit and installing a room inside the mine to house
the treatment system.
1.2 General Information
Acid rock drainage is a serious environmental
problem facing many inactive, abandoned, and
active mine sites throughout the United States.
ARD chemistry is generally discussed in this
section and further discussed in the following
sections. Some environmental problems resulting
from mining operations occur when reactive
sulfide-bearing ore bodies and mine wastes are
exposed to oxidizing environments and create
ARD. Acid rock drainage is produced when
metal-sulfide minerals, particularly pyrite (iron
disulfide), come in contact with oxygen and water.
This reaction results in increased acidity (lowered
pH) of the water and increased toxic metal
mobility. The weathering process of other base
metal sulfides is similar to the process described
for pyrite, although it may not produce acid.
Common metals associated with ARD are arsenic,
cadmium, copper, iron, manganese, and zinc.
Arsenic is a metalloid element while cadmium,
copper, iron, manganese, and zinc are metals.
Within ambient systems, arsenic can occur as
arsenate [As(V)] orarsenite [As(III)]. Over the
natural pH range of most soils and waters, the
principal species of arsenate is H2ASO4"2 and
arsenite is H3AsO3.
Conventional technologies for removing heavy
metals from ARD use coagulation/filtration,
adsorption media, and/or biological treatment
processes. Topography, climate, cost,
infrastructure, treatment volumes, and metal
loading can present difficulties for any technology.
Remote abandoned mine sites are particularly
impacted because they often: (1) do not have
electricity; (2) have extreme weather conditions;
(3) have limited area available for a treatment
plant; and (4) do not have year-round access. A
need exists for a simple, low-maintenance
technology to reduce heavy metals from ARD at
remote sites.
Because of the high ratio of iron to other metals in
the Susie Mine water, conventional treatment
technologies have limited applicability in this
situation. This is due to difficulties associated
with high particulate loadings, elevated total
suspended solids (TSS), and high concentrations
of total dissolved solids (i.e., reactor plugging,
media coating, etc.). Therefore, it was postulated
that adsorption of the heavy metals onto
ferrihydrite and co-precipitation followed by
solid/liquid separation would be the most effective
treatment process. An added benefit was to use
the physical characteristics of the Susie Mine in
such a manner as to enhance the overall efficiency
of the proposed treatment process. These included
(1) using the mine as a physical structure to house
the treatment technology, (2) using the higher
temperature of the mine water as a heat source to
prevent freezing in the winter, and (3) taking
advantage of the ARD chemistry (described
below) to more efficiently remove metals of
concern.
1. 2. 1 Acid Rock Drainage Chemistry
Overview
The production of ARD occurs through the
weathering of pyrite (FeS2). The pyrite is
dissolved over time by the groundwater, which is
indicated by Reaction 1 below. Mine water often
has high acidity and, therefore, a lower pH due to
acid being produced in the weathering of pyrite.
FeS2 +7/2O2 + H2O -> Fe2+ +2SO4
[1]
pyrite + oxygen + water ->• ferrous + sulfate + acidity
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The second reaction, which occurs when the mine
water comes in contact with oxygen, involves the
conversion of ferrous iron (Fe2+) to ferric iron
(Fe3+). The conversion of one mole of ferrous iron
to one mole of ferric iron consumes one mole of
acidity. Certain bacteria can increase the rate of
oxidation from ferrous to ferric iron, but the
presence of these bacteria is not required. This
reaction is referred to as the "rate determining
step" in the overall acid generating sequence.
2Fe2
O2
2 Fe3+ + H2O [2]
(ferrous Fe + oxygen + acidity ->• ferric Fe + water)
The third reaction that may occur is the hydrolysis
of Fe+3. Three moles of acidity are generated as a
byproduct. Many metals are capable of
undergoing hydrolysis. The formation of ferric
hydroxide precipitate (solid generally referred to
as ferrihydrite) occurs if the pH is above
approximately 3.5.
Fe3+ + 3 H2O -> Fe(OH)3 ^ + 3 FT
[3]
(ferric Fe + water ->• ferric hydroxide + acidity)
Throughout all these reactions, acidity is being
produced and consumed. Without a buffer (i.e.,
limestone, caustic, or calcium hydroxide) present,
the mine water discharge will be acidic.
1.2.2 Geochemistry Review
To understand the results and terms discussed in
the following sections, it is important to review
some dominant chemical reactions (i.e.,
ferrihydrite formation, precipitation/dissolution,
adsorption, etc.) that occur in waters such as these.
The geochemical processes controlling arsenic
mobility are reviewed below (USGS, 2001).
Two types of processes largely control arsenic and
heavy metal mobility in aquifers: 1) adsorption
and desorption reactions; and 2) solid-phase
precipitation and dissolution. Attachment of
arsenic and heavy metals to an iron oxide surface
is an example of an adsorption reaction. The
reverse of this reaction is an example of
desorption. Solid-phase precipitation is the
formation of a solid phase from components
present in aqueous solution. Precipitation of the
mineral ferrihydrite from the ferric ion in water is
an example of solid-phase precipitation. The
ferric ion is not stable in an aqueous environment
above pH 7 and will precipitate as 1) ferrihydrite -
Fe(OH)3 and/or ferrioxy sulfates; 2)
schwertmannite - Fe8O8(OH)6SO4; and 3)
greenrust- Fe4Fe2(OH)12SO4 (Robins, 1984,
Jambor and Dutrizac, 1998). Figure 1-1 is an
Eh/pH stability diagram showing iron speciation in
the Susie/Valley Forge Mine water. Solid-phase
precipitation and dissolution reactions are
controlled by solution chemistry: pH, oxidation-
reduction potential (ORP) or redox, and chemical
composition. The formation of ferrihydrite
depends on the sulfate concentration. For the
example shown in Figure 1-1, where the sulfate
level is appreciable, ferrioxysulfates will likely
form.
The chemical reaction for the formation of
ferrihydrite (Fe5HO8.4H2O) is shown below:
5Fe+3 + 12H2O -> Fe5HO8.4H2O fs1 + 15H+
[4]
Arsenic adsorption and desorption reactions are
influenced by changes in pH, redox reactions,
presence of competing anions, and solid-phase
structural changes at the atomic level. Arsenic is a
redox-sensitive element. Arsenate and arsenite are
the two forms of arsenic commonly found in
groundwater. Arsenate generally predominates
under oxidizing conditions, while arsenite
predominates in a reducing environment. Under
the pH conditions of most waters, arsenate is
present as the negatively charged oxyanions
H2AsO4", F£AsO42", or AsO4"3 and arsenite is
predominately present as the uncharged species
H3AsO30 (Masscheleyn, 1991).
Adsorption during co-precipitation of arsenate and
ferric hydroxide is illustrated by Reaction 5:
AsO4 3 + Fe(OH)3(s) -> Fe(OH)3(s) + AsO4 3(ad) [5]
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The dissolved arsenic is removed from the
oxidized water by lime neutralization in Reaction
6 in the presence of the Fe+3 that results in the
formation of arsenic-bearing ferrihydrite (hydrous
ferric oxide). Neutralization with sodium
hydroxide can also be utilized.
Ca(OH)2
Ca+/ + 2H2O
[6]
The ferrihydrite may be formed by the natural
presence of iron in solution or it may be added as a
reagent (i.e., ferric chloride, ferric sulfate, or
ferrous sulfate) in sufficient quantities to
effectively remove the dissolved arsenic. Studies
have shown that if Fe+3 is present in solution, the
maximum adsorption capacity for arsenic onto the
ferrihydrite is 0.7-mole arsenate per mole iron. On
the other hand, if no Fe+3 is present and it is added,
then the maximum adsorption capacity is 0.2-mole
arsenate per mole iron (Nishimura and Umetsu,
2000; Nishimura et al, 2000). A solid-liquid
separation may then be performed and
accomplished by a process involving conventional
settling/flocculation followed by pressure
filtration. Adsorption of heavy metals also occurs
during the ferrihydrite precipitation process.
A number of studies have indicated that various
complexes are formed in the adsorption of
arsenate on ferrihydrite (Manceau, 1995; Sun and
Doner, 1996; Fendorf et al, 1997). Extended x-ray
absorption fine structure (EXAFS) studies on
arsenic-bearing ferrihydrite formed at pH > 7,
have shown that arsenate is adsorbed onto
ferrihydrite as a strongly bonded inner-sphere
complex with either monodentate or bidentate
attachment (Waychunas et al, 1993; Waychunas
et al, 1995). It has also been reported that
monodentate attachment predominates near the
optimal pH 4 to 5 for adsorption.
The adsorption of arsenite onto ferrihydrite has
also been investigated, but the optimal adsorption
in this case occurs at pH 8 to 9 (Nishimura and
Umetsu, 2000) and, although it seems an efficient
process, there is no evidence that the adsorbed
species is in fact arsenite. It may be that during
the process, oxidation of arsenite will occur with
some ease, being balanced by the reduction of
ferric iron to ferrous iron in the ferrihydrite
structure. It is well known that ferrous iron
substitution in ferrihydrite does occur (Nishimura
et al, 2000).
1.3 Project Objectives
The overall objective of MWTP, Activity III,
Project 42 was to design, construct, and test the
operation and functionality of a treatment facility
to remove arsenic and heavy metals from the
selected demonstration site, the Susie Mine
discharge in Rimini, Montana. Specifically, the
objective was to achieve arsenic and metals
removal to levels below the Circular WQB-7
Montana Numeric Water Quality Standards shown
in Table 1-1 (Montana Department of
Environmental Quality, 2004). The 2004 WQB-7
standards are calculated using the Chronic Aquatic
Life Standard based on 100 milligrams per liter
(mg/L) hardness and total recoverable analysis.
The regulatory standards for metals are hardness-
based standards. Since the hardness of the Susie
Mine discharge is greater than 1,000 mg/L, the
maximum WQB-7 hardness of 400 mg/L is used
to calculate the standards. The arsenic standard is
listed as 10 micrograms per liter (|ig/L), reflecting
the new Federal maximum contaminant level
(MCL) for drinking water. WQB-7 does not list
an aquatic standard for manganese; instead, a
secondary MCL (aesthetic, taste) of 50 (ig/L is
listed.
Table 1-1 summarizes the regulatory standards
(action levels) and the current Susie Mine
discharge concentration of contaminants evaluated
for this project. The untreated Susie Mine
discharge values are from the CDM Acid Mine
Drainage Study (CDM, 2003). Greater detail from
that study can be found in Table 1-2. Analytical
data results and the treatment system capabilities
are discussed in detail in later sections.
This project was a demonstration, investigative by
design, and should not be construed as an attempt
to fully remediate the Susie Mine discharge.
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1.4 Site Description
The field-scale demonstration was performed at
the Susie Mine in Rimini, Montana. Figure 1-2
shows the locations for the Rimini Mining District
near Rimini, Montana and the MSB Testing
Facility in Butte, Montana. Analytical information
for the Susie Mine water is shown in Table 1-2
with historical data for the Susie Mine discharge
provided in Appendix B. Other historical
information on the Susie Mine water can be found
in the 2002 COM AMD Study (COM, 2003) and
more recently in EPA's First Five-Year Review
Report for Upper Tenmile Creek NPL Site (EPA,
2008). The COM report states that the flow rate of
the Susie Mine discharge fluctuates from 4 gallons
per minute (gpm) to 6 gpm. During preliminary
testing in Phase I, the flow rate was measured at
about 5 gpm.
The treatment system was housed inside the Susie
Mine and was designed to treat up to 10 gpm and
operate 24 hours per day and 7 days per week.
The equipment layout is shown in Figure 1-3.
EPA Region 8, as a task in their FY05 Remedial
Action Contracts (RACs), mined out a room large
enough for the proposed treatment process. The
Susie Mine water was collected and treated inside
the mine. The two products from the treatment
process were treated water and process sludge,
which were disposed as specified in the
Technology Description section.
1.5 Experimental Design
The purpose of this project was to demonstrate the
effectiveness of the Reductive Precipitation
Process for treating the entire flow of the Susie
Mine discharge for removal of arsenic and zinc.
In addition, the effect of the technology on other
constituents (i.e., cadmium, copper, iron, and
manganese) was evaluated. Other parameters
necessary for process control were also measured.
To evaluate the critical objectives and investigate
other aspects of the project, an experimental
design was developed. The experimental design
used sampling and analysis to monitor, operate,
and evaluate the Reductive Precipitation Process.
1.5.1 Sampling Locations
Samples were collected from the sampling
locations summarized in Table 1-3. The piping
and instrumentation diagram (P&ID) for the
process is provided in Appendix C. The sample
port locations are shown on the P&ID, and the
approximate locations can be seen on Figure 1-3.
1.5.2 Field Measurements
Table 1-4 summarizes the critical and noncritical
measurements that were collected by location and
sampling type. Critical measurements were
necessary to achieve critical project objectives
while noncritical measurements provide additional
information about process control, as well as
information of interest to project participants.
Field measurements included temperature, pH, and
ORP.
1.6 Technology Description and Design
1.6.1 Technology Description
The Reductive Precipitation Process was the
technology used to remove arsenic and heavy
metals from the Susie mine water. This process
consisted of:
- pH adjustment using hydrated lime
[Ca(OH)2] to produce ferric hydroxide
precipitate combined with adsorption of
arsenic and metals onto ferric hydroxide
precipitate;
- natural settling of the formed precipitates;
- filtration to remove suspended solids; and
- a polishing step using granular ferric
hydroxide or ZVI to remove remaining
arsenic (if necessary).
Although it was very effective during laboratory
treatability tests, the final GFH polishing step was
not implemented at the Susie Mine due to funding
limitations. In addition, the intended two-stage
process was shortened to one stage because of
problems associated with solids settling. More
information on these issues can be found in
Section 1.6.6, System Verification and
Acceptance.
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The ferric hydroxide precipitate or iron sludge was
collected and stored as sludge or as a filter cake
and then properly disposed of at the Luttrell
Repository. Treated water was discharged to the
existing 6-inch pipe originating in the Susie Mine
that discharged to a series of settling ponds which
then discharged to Tenmile Creek.
1.6.2 Technology Design
The two-stage iron precipitation/filtration process
designed for this project was based on the
Reductive Precipitation Process developed by
MSB and Dr. Larry Twidwell, Metallurgical
Engineering Professor at Montana Tech of the
University of Montana and President of Montana
Enviromet. The process was first implemented by
MSE in 1998 at a Superfund site in Emeryville,
California to treat the arsenic-contaminated
groundwater. During preliminary laboratory
testing, the two-stage iron precipitation/filtration
process removed over 99.6% of the arsenic and
over 99.9% of the heavy metals from Susie Mine
water. When necessary, GFH was used to remove
the remaining arsenic to below the Montana
Circular WQB-7 Standard (Montana Department
of Environmental Quality, 2004).
The process flow diagram of the treatment system
is provided in Appendix C. The P&ID, mine
elevation drawing, and general layout drawing
showing the equipment in the mine are provided in
Appendix C. A simulation model of the process,
which identified the process flow rates and
products, is provided in Appendix D. This model
was developed by Dr. Larry Twidwell to support
the process design efforts. The simulation model
was used as a process management tool since it
could be modified during the demonstration
project to better simulate the actual process and
products generated.
The design of the complete water treatment system
was accomplished as follows.
• Design and review requirements for the
proposed system were established for the
project as Quality Level B per the MSE
Quality Management Manual. Reviews
included an independent technical review
(ITR) by qualified peers of all work requests
and work packages prior to being issued in the
field, as well as an informational design
review of the system.
• All design work was completed by MSE in
accordance with current established design
procedures. Additional requirements detailed
by applicable codes and standards were
incorporated into the design work.
• Any changes or modifications to the design as
a result of error or improvements were
accomplished by completing the required
work package for ITR and obtaining approval.
• Modifications to the drawings or the creation
of required drawings were completed on a
drafting-only work package. The modified
drawing was approved and signed off by this
process.
1.6.3 Technology Construction
Most components (i.e., process tanks, pumps,
mixers, etc.) for the Reductive Precipitation
Process were off-the-shelf items. The coned-
bottom tanks (Tanks 301 through 308) were
modified to function as static settlers. Tank
modifications were completed at the MSE Testing
Facility in Butte, Montana.
The components for the Reductive Precipitation
Process were installed in the Susie Mine according
to the process flow diagram and general layout
diagram. Field piping was implemented to
complete installation of the process. See
Figure 1-3 for equipment layout details.
Process equipment [i.e., flowmeter (LCV-101), pH
probes (pH-114, pH-128, pH-176)] was calibrated
per manufacturer specifications prior to operation.
The frequency of the process equipment
calibration was performed in accordance with
manufacturer's specification or more frequently if
required to maintain the reliability/operability of
the process. Calibration of process equipment was
documented in the daily logbook. Periodic audits
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were performed on this equipment according to
the determined schedule.
1.6.4 Documentation
Prior to system operation, an operating and
maintenance (O&M) manual and a detailed health
and safety (H&S) Plan were written specifically
for the Reductive Precipitation Process at the
Susie Mine.
1.6.4.1 Operating and Maintenance Manual
The O&M manual was based on a similar
treatment system at a Superfund site in
Emeryville, California, which MSB installed and
operated. A senior process engineer,
knowledgeable with the system, trained operators,
engineers, and safety personnel prior to process
startup. The O&M manual included:
- appropriate controls for materials
(including consumables) and measuring
and testing equipment;
- configuration management; and
- operating procedures and parameters for
specific components and systems
configuration.
Documentation requirements for the system
operating instructions/guides were available on
site in the O&M manual. Daily operation and
maintenance activities were documented in the
daily logbook.
1.6.4.2 Health and Safety Plan
The project-specific H&S plan (MSB, 2006) dealt
with safety issues associated with the operation
and maintenance of the Reductive Precipitation
Process. The following items were part of the
H&S plan.
• Material safety data sheets on all reagents and
chemicals used during the demonstration were
placed in a notebook and maintained on site
during the life of the project.
• All required personal protective equipment for
entering the Susie Mine and for the operation
and maintenance of the system was identified.
• Procedures for entering the mine and
inspecting the mine walls and ceiling were
written.
• A daily H&S meeting logbook was maintained
throughout the demonstration.
• Daily safety meetings were held to instruct
MSB personnel and others entering the Susie
Mine on H&S issues associated with process
operation and mine structural integrity.
• Daily H&S log sheets were generated and
maintained at the demonstration site.
1.6.5 Assessment and Response
External review of the preliminary work (i.e.,
Interim Report - Physical Solutions for Acid Mine
Drainage at Remote Sites Demonstration Project,
Phase I for Mine Waste Technology Program,
Activity III, Project 42) conducted by MSB was
completed by EPA Region 8 representatives;
RACs Region 8 contractor, COM; MDEQ; and
ASARCO representatives. During apre-review
meeting in Helena, Montana on June 2, 2004, a
COM water treatment expert informed the
attendants including EPA, DOE, EPA Region 8,
MDEQ, COM, and MSE representatives (see
attendance list in Appendix A) that the proposed
MSE treatment process to treat the Susie Mine
water was appropriate.
MSE completed an ITR of the proposed treatment
system on January 26, 2006 (see attendance list in
Appendix E). All comments received from the
ITR were reviewed by the MSE Project Manager
and MSE Project Engineer. Appropriate
comments and suggestions were incorporated in
the design.
1.6.6 System Verification and Acceptance
The Reductive Precipitation Process at the Susie
Mine was started and operated using verification
requirements and acceptance criteria established
prior to implementation.
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1.6.6.1 Preliminary Testing
After the treatment system components were
installed inside the Susie Mine, the system was
checked to determine that all equipment
functioned properly and that process flow rates
were achievable. The system was designed to
operate at 10 gpm. Initially, the system was
operated at this flow rate with clean water to test
piping and plumbing for leaks and to verify that
the design flow rate could be achieved. All
process and analytical instruments were calibrated
and evaluated for accuracy and repeatability as
specified by the manufacturer.
1.6.6.2 Startup
The goal of the startup was to optimize the process
using parameters established during the laboratory
treatability studies to optimize the system for
arsenic and zinc removal. Following preliminary
testing, the system was operated as designed and
outlined in the O&M manual to remove arsenic
and heavy metals from the Susie Mine water. The
average flow rate of the Susie Mine water was
expected to be about 5 gpm. The actual flow rate
was slightly less than this throughout the
demonstration.
1.6.6.3 Demonstration
During the demonstration, data was collected to
determine the effectiveness of the proposed
treatment system for removing arsenic and zinc
from the Susie Mine water. Other metals were
also analyzed to show the system effectiveness for
non-critical parameters. O&M costs were then
generated to perform a cost analysis of the
treatment system. The data generated during the
demonstration was utilized by EPA Region 8 and
the MDEQ to make decisions on operating the
treatment system long term.
Following the commissioning startup, the
treatment system was operated for a period of four
months (September 26, 2006 through January 26,
2007) to demonstrate its feasibility. The
demonstration was originally intended to run for at
least six months, but was shortened due to limited
funding. Several problems were encountered
during the demonstration. The lime used to
initially raise the pH of the mine water during the
first stage contained small amounts of sand or
gravel that clogged the lines and pumps, shutting
the system down at times. This caused delays
until a source of better lime could be found.
Another problem that plagued the system was that
the settling tanks were undersized and the quantity
and settling rate of the solids hampered their
effectiveness. Partway through the demonstration,
two additional tanks were added to help alleviate
the problem. However, the settling process was
never optimized.
Due to these issues, the process was changed from
a two-stage operation to a single-stage operation.
The two-stage process consisted of increasing the
pH to a range between 8.0-8.5, removing solids,
adding ferrous sulfate, raising the pH to a range
between 10.0-11.0, and removing additional
solids. For the single-stage process, the pH was
raised to between 10.5-11.0 immediately, and then
solids were removed in one step. While the single
stage process is able to remove the vast majority
of metals, the advantage of the two-stage process
is that lower levels of arsenic could be achieved
due to adsorption on the iron precipitate.
The GFH or ZVI polishing step, originally planned
for the process, was not implemented due to
funding limitations.
1.6.7 Process Flow Description
Refer to Figure 1-3 for a diagram of equipment
layout. Susie Mine water was collected in the adit
behind a man-made dam. From the dam, the mine
water flowed by gravity to Makeup Tank T-101.
Filter backwash water was also collected and
recycled back to T-101. Process feed water was
pumped from T-101 by Pump P-101. The process
flow rate was controlled by maintaining a constant
level in T-101 using a level transmitter (LT 116)
and level PLC input (LX-116). The PLC output
(FZ-105) controlled the level control valve (LCV-
101). As LCV-101 automatically adjusted to the
PLC or controller's setpoint level, a flow rate was
established that is equal to the process feed water
influent to T-101. Excess process water from
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Pump P-101 was recirculated through a hand valve
(HV-104) back to T-101. As the effluent water
from the Susie Mine fluctuated, the level control
system maintained the setpoint level and the
process water flow rate was equal to the mine
water flow rate.
Process water leaving the level control system
continued on through the first stage, encountering
two static mixers (SM-101 and SM-102) and a
flow meter (FM-101) before discharging into the
settlers (T-301 and T-303). Flow rate to the
settlers was controlled manually by utilizing a
mechanical splitter and hand valves (FfV-108 and
HV-109).
Primary settling tanks consisted of Tank T-301 in
series with Tank T-302, and Tank T-303 in series
with Tank T-304. Permeate from settlers T-301
and T-303 flowed by gravity to settlers T-302 and
T-304, respectively. Permeate from T-302 and
T-304 discharged to the 400-gallon permeate tank
T-102 where the second level control system
controlled the flow rate through the second stage.
Process transfer pump P-102 pushed the water
through static mixers SM-103 and SM-006, to the
secondary settling tanks (T-305 in series with
T-306 and T-307 in series with T-308). Similar to
the first stage, settling tanks T-306 and T-308
overflowed to the 400-gallon permeate tank
(T-103). Here the third level control system along
with pump P8 regulated the flow rate through the
screen filtering and GFH columns. Process pump
P-103 pushed the T-103 permeate through
SM-105, screen filters, and GFH columns to the
1,600-gallon process water tank (T-104). The
screen filters were programmed to switch
manually with a high differential pressure alarm.
The system was capable of auto switching with
reprogramming. Initially, a slipstream of filtered
second stage permeate (1.0 gpm) was pushed
through the GFH columns. The slipstream to the
GFH columns was controlled using a hand valve
(HV-122) and the remaining flow was pumped to
T-104. Due to funding limitations, both the screen
filters and GFH columns were bypassed. The
treated water in Tank T-104 was discharged to the
Tenmile Creek by gravity using either the existing
system or Process Line 114.
A portable trailer with dual pneumatic pumps
(P-301 and P-302) was used to manually push the
ferrous arsenate and ferrihydrite sludge from each
of the settling tanks to the sludge pH adjustment
tanks (T-309 and T-310). Each settling tank had a
hand valve (HV-301 through HV-308) that was
opened manually to isolate the sludge in each
settling tank for transfer. The sludge from the
primary and secondary settling tanks was pumped
from Process Lines 301 and 303 and pushed
through Process Line 302 to Tanks T-309 and
T-310. The sludge was then treated with calcium
hydroxide and iron in order to pass the toxicity
characteristic leach procedure (TCLP) standards.
Once the sludge passed TCLP, it was pushed to
the outdoor sludge storage tanks (T-311, T-312,
and T-313) through Process Line 308 at an
estimated 7% to 13% solids. The treated sludge
was filtered to remove most of the water and
placed into 5 5-gallon drums, which were sealed
for disposal. Water from the filter press was then
recycled in line to T-105.
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Susie Water
m
-P
H
o
— Conditions
S 1250ppm
Fe 119ppm
File susie
Figure 1-1. Iron speciation diagram for Susie/Valley Forge Mine
water (thermodynamic data from STABCAL 2004).
ACAD#: DEE14-1001
10/28/03
Figure 1-2. Site map.
10
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P-Z04 P-2DS P-104 J-203 H B P-203
120 VAC OUTLET (DUPLEX)
240 VAC OUTLET (DUPLEX)
PUMPS
Figure 1-3. Susie Mine Reductive Precipitation Process equipment layout.
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Table 1-1. Susie Mine Contaminant Concentrations and Regulatory Standards
Untreated Action Level
Contaminant Susie Mine Discharge WQB-7 Standards
(n.g/L)
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Zinc
23,300
241
69.7
228,000
3.8
20,500
50,200
10
0.76
30.5
300
18.6
50*
388
* Secondary MCL
Table 1-2. Analytical Information for the Susie Mine Waters (COM 2002 AMD Study)
Analytical Data
PH
ORP [millivolts (mV)]
TSS (mg/L)
Aluminum
Antimony
Arsenic
Cadmium
Calcium
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Selenium
Thallium
Zinc
Rimini Mining District Water
Susie/Valley Forge
4.7
162
29
Analytes (jig/L)
1,250
<0.5
23,300
241
251,000
69.7
228,000
3.8
93,700
20,500
55.7
6.1
0.12
50,200
12
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Table 1-3. Sample Locations
Sample Location
101
102
103
104
105
106
107
301
302
Sample Description
Feed, process feed water, Susie Mine discharge
Settler 1 feed, process water following pH adjustment with Ca(OH)2 and mixing (needed
to check process chemistry)
Settler 1 overflow, process water after first stage precipitation
Settler 2 feed, Settler 1 overflow following addition of ferrous sulfate and Ca(OH)2 and
mixing, needed to check process chemistry
Settler 2 overflow/GFH feed, process water after second stage precipitation
GFH intermediate, process water after first GFH column
Process effluent
Slurry from settler
Slurry after being treated to pass TCLP and prior to being pumped to storage tanks
Matrix
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Solids
Solids
Table 1-4. Laboratory Analyses and Field Measurements
Parameter
Temperature
PH
ORP
Flow Rate/Total Flow
TSS
Density - % Solids
Sampling
Classification Matrix Locations Frequency
Noncritical Aqueous 101 through 107 Daily
Noncritical Aqueous 101 through 107 Daily
Noncritical Aqueous 101 through 107 Daily
Noncritical Aqueous Flow in and out of Daily
system at flow meter
or totalizer locations
Noncritical Aqueous 101 through 107 Every other week
Noncritical Solids 301,302 Slurry from 301 and 302 analyzed
Responsible
Laboratory
MSE
MSE
MSE
MSE
MSE
MSE
Total Metals (Al, Ca, Noncritical Aqueous 101,103,105,107
Cd, Cu, Fe, Mg, Mn,
Pb)
Dissolved Metals (Al, Noncritical Aqueous 101,103,105,107
As, Ca, Cd, Cu, Fe,
Mg, Mn, Pb, Zn)
Total As, Zn
TCLP
(Metals are silver, As,
barium, Cd, Cr,
mercury, Pb, Se)
Critical Aqueous 101, 103, 105, 107
Noncritical Solids 302
when T-309 or T-310 become full
Every other week MSE
Every other week MSE
Daily during startup and MSE
commissioning; Monday and Friday
for long-term demonstration
Slurry from 302 analyzed when T-309 MSE
or T-310 became full and prior to
pumping slurry to T-311. If the sample
passed TCLP, the slurry in T-309 or
T-310 was pumped to T-311. If the
sample failed TCLP, the contents in
T-309 or T-310 was reconditioned with
reagents and analyzed again. This was
repeated until the slurry passed TCLP.
13
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2. Results and Discussion
The Phase I scope of work (laboratory treatability
testing) was completed in March 2006 and the
findings are summarized in the Interim Report for
the Physical Solutions Project (MSB, 2006). This
section discusses laboratory treatability results
briefly, but deals primarily with results obtained
during the field demonstration at the Susie Mine.
A summary of the quality assurance (QA)
activities from the project specific quality
assurance project plan (QAPP) is contained in
Appendix F.
2.1 Treatability Study Results
The overall objective of MWTP, Activity III,
Project 42 was to design, construct, and test the
operation and functionality of a treatment facility
to remove arsenic and heavy metals from the
selected demonstration site, the Susie Mine
discharge in Rimini, Montana. To meet this
objective in the field, laboratory treatability tests
were performed. The objective of the treatability
tests was to test the Reductive Precipitation
Process on various mine waters, including the
Susie Mine. Process optimization in the
laboratory was performed to save time in the field
and to achieve arsenic and metals removal to
levels below the Circular WQB-7, Montana
Numeric Water Quality Standards, provided in
Table 2-1 (Montana Department of Environmental
Quality, 2004). Data collected during these
treatability tests, shown in Table 2-1, indicated
that all the contaminants could be consistently
reduced to below the WQB-7 Standards with the
exception of manganese. It was anticipated that
further process optimization in the field would
reduce the manganese to acceptable levels.
2.2 Field Demonstration Results
Because of the success of the laboratory
treatability tests, the process was taken to the field
and implemented at the Susie Mine. The system
was designed for arsenic and zinc removal by
using the knowledge gained from the laboratory
studies. However, while zinc was effectively
removed, the field system was never able to
achieve arsenic levels below the WQB-7 Action
Level of 10 (ig/L. The October 3, 2006 treated
effluent sample had the lowest arsenic level (51.9
(ig/L) that also had all the non-critical parameters
measured. This data was then reported as the best
that the Reductive Precipitation Process was able
to achieve within the budget and schedule
constraints of this project. A summary of these
treated water results is shown in Table 2-2, along
with the raw mine water discharge results, method
detection limits (MDL), and the WQB-7 standards.
As shown in Table 2-2, most contaminant levels
were substantially reduced by the Reductive
Precipitation Process. Permanent operation of this
technology at the Susie Mine would result in the
removal of the vast majority of the contaminants
of concern, which, in turn, would reduce the
contamination in Tenmile Creek. Table 2-3
summarizes the effluent data. The data includes
the number of samples and the average, standard
deviation, maximum, and minimum concentration
for each contaminant. A brief synopsis of each
parameter follows.
2.2.1 Arsenic
As shown in Table 2-2, the concentration of
arsenic in the October 3, 2006 Susie Mine effluent
was reduced by almost three orders of magnitude -
from 23,300 to 51.9 (ig/L. Full time
implementation of this technology at the Susie
Mine should have resulted in the removal of about
99.8% of the total arsenic in the incoming stream.
However, as Table 2-2 also shows, the WQB-7
Action Level Standard was never achieved during
the field demonstration. During numerous process
optimization attempts, arsenic in the treated
samples varied from 38 to 680 (ig/L with a mean
concentration of 248 ±195 (ig/L standard
deviation, which was higher than the action level
standard for all twenty-five samples.
The low values seen during the laboratory
treatability tests were not achieved. There were
several reasons for this. As explained previously,
14
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the ZVI or GFH process that was proposed as a
polishing step to remove residual arsenic was
never implemented due to lack of funds. In
addition, the settling problems discussed
previously, caused problems that did not allow full
process optimization. Other process problems and
the shortened project schedule also made
optimization difficult.
Figure 2-1 shows arsenic data from all 25 samples.
A logarithmic scale is used for arsenic
concentration due to the large differences between
the influent and effluent concentration data.
2.2.2 Cadmium
The level of cadmium in the Susie Mine October
3, 2006 discharge was reduced from 241 to 0.53
(ig/L, slightly below the WQB-7 action level
standard of 0.76 (ig/L. This is a 99.8% reduction,
which eliminates most of the cadmium from the
effluent. As process conditions were changing,
cadmium discharge levels during the field
operation varied from 0.15 to 3.4 (ig/L.
2.2.3 Copper
The average inlet concentration of copper (69.7
Hg/L) in the Susie Mine water is about double the
WQB-7 action level standard of 30.5 (ig/L.
Following treatment, the level of copper in the
October 3, 2006 discharge was reduced to a level
below the detection limit. As part of the
optimization process, the process parameters were
varied throughout these tests, resulting in copper
discharge levels that varied from non-detect to 4.7
(ig/L (total of five samples).
2.2.4 Iron
The level of iron in the mine discharge was
reduced by more than 99.8%, from over 228,000
to 375 (ig/L for the October 3 sample. This was
slightly greater than the action level standard of
300 (ig/L. As process conditions were changing,
iron levels in the treated effluent varied from 83 to
1,780 (ig/L (total of five samples).
2.2.5 Lead
The amount of lead in the untreated mine water
was already below the WQB-7 action level
standard of 16.8 (ig/L. In the October 3, 2006
treated effluent, the concentration of lead was
reduced from 3.8 (ig/L to a level of 0.149 (ig/L,
which is barely above the instrument detection
limit of 0.1 (ig/L. The lead concentration in the
five samples of treated effluent varied from 0.13 to
0.97 (ig/L throughout the optimization process.
2.2.6 Manganese
As shown in Table 2-2, the level of manganese in
the mine discharge was reduced substantially by
the Reductive Precipitation Process. As with most
of the other contaminants, the implementation of
this technology at the Susie Mine would
dramatically reduce loading to Tenmile Creek.
However, as the table also shows, the WQB-7
discharge standard of 50 (ig/L was not consistently
met during the field demonstration. The treated
Susie Mine effluent on October 3, 2006 was
reduced from 20,500 to 680 ng/L, a 96.7%
reduction. While the process was being
optimized, manganese in the treated effluent
varied from 16.6 to 1,520 (ig/L (total of five
samples).
There was also difficulty during laboratory
treatability tests in meeting action level standards.
It was believed that better results could have been
achieved for reasons identified for the arsenic
treatment as explained above (i.e., one stage
versus two stages and no polishing step).
2.2.7 Zinc
In addition to arsenic, zinc was the other
measurement specified as critical for this
demonstration. Unlike arsenic, however, the
treatment goal for zinc was easily achieved. On
October 3, 2006, the concentration of zinc in the
Susie Mine discharge was reduced from 50,200 to
24.3 (ig/L, a reduction greater than 99.9%. This is
about double the MDL of 10.0 (ig/L listed in the
project QAPP (MSB, 2006). Only two of the 25
samples were above the WQB-7 action level
standard of 388 ng/L. These exceedences
occurred due to process upsets that were easily
fixed. Throughout the field operation, zinc in the
15
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treated effluent varied from 2.5 to 816 (ig/L (total
of 25 samples).
2.2.8 Sludge
The total amount of sludge produced during the
demonstration was 14 drums each containing 350
pounds each. This is equivalent to 4,900 pounds
of sludge. Measurements indicated that the sludge
contained about 30% solids.
2.3 Contaminant Reduction Calculations
As stated previously, the primary project goal of
reducing arsenic below regulatory standards was
not achieved. However, there is no doubt that the
Tenmile Creek drainage benefited greatly as a
result of the implementation of the Reductive
Precipitation Process at the Susie Mine. In order
to quantify these tangible benefits, the total
quantity of contaminants removed from Tenmile
Creek as a direct result of this project was
calculated. Data used for the calculations were the
historical Susie Mine water values (CDM, 2003)
and the October 3, 2006 treated water
measurements. The inlet flow totalizer at the
Susie Mine registered about 73,176 gallons of
water treated over the four-month test period.
There were many interruptions during this period
for problems and process modifications.
Extrapolation to a system running at 4.0 gpm over
an entire year was also done to determine the
annual reduced metal loading. These results are
shown in Table 2-4.
As shown in Table 2-4, implementation of this
technology has the potential to remove large
quantities of contaminants from Tenmile Creek.
For example, over 400 pounds of arsenic and 800
pounds of zinc could be removed annually.
2.4 Technology Costs and Process
Economics
The treatment system can be classified as a small
coagulation/filtration system with adsorption of
arsenic onto GFH as a polishing system. The
system was designed to treat 10 gpm or 0.014
million gallons per day of Susie/Valley Forge
Mine water. The adit flow rate ranged from 3 to
6.4 gpm. Operational costs are calculated for
treating an average of 5 gpm. Annual reagent
costs are provided in Table 2-5. The unit price for
each reagent was taken from the EPA document,
Technologies and Costs for Removal of Arsenic
from Drinking Water (US EPA, 2000). The GFH
cost is a quote from USFilter Corporation received
in 2004.
Table 2-6 is a preliminary capital cost breakdown
for a package coagulation/filtration water
treatment plant with a 12-square foot (ft2) filter
area. The model was taken from the EPA
document referenced above. This cost model was
used because of similarities in the process
equipment.
Table 2-7 is an estimated annual cost breakdown
to operate the proposed system. Assumptions used
to determine the operational costs are as follows.
• Labor rates for an operator - $48 per hour for
4 hours per week
• Labor rates for a water treatment engineer -
$95 per hour for 1 hour per week
• Analytical sampling - $500 per quarter
• Electricity - $0.08/kilowatt hour (kWh)
• Building energy use - 102.6 kWh/ft2/year
• Building - 500 ft2
• Annual safety & health, and hazardous
material training would be required
It was estimated that 9,554 pounds of ferrihydrite
sludge would be produced annually by the process.
In addition, 1,318 pounds of spent GFH would
require disposal. All solid waste from the process
would be sent to the Luttrell Repository. To
determine a cost for disposing of the process
solids, $0.50 per pound was used for each solid
waste. This cost estimate, as shown in Table 2-8,
included all shipping and handling (i.e., labor,
vehicle, food).
16
-------
Susie Mine Water Treatment System
Total Arsenic
•Influent ^^"First Stage Second Stage Effluent Action Level
100 -,
0.01
9/20/2006 10/5/2006 10/20/2006 11/4/2006 11/19/2006 12/4/2006 12/19/2006 1/3/2007 1/18/2007 2/2/2007
Date
Figure 2-1. Total arsenic values of Reductive Precipitation Process.
Table 2-1. Bench-Scale Tests - Standards, Feed Concentrations, and Effluent Levels
Action Level Untreated Concentration from
Contaminant WQB-7 Standards Susie Mine Discharge Bench-Scale Testing
(p,g/L)
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Zinc
10
0.76
30.5
300
18.6
50
388
23,300
241
69.7
228,000
3.8
20,500
50,200
0.9-5.43
ND1
<5.0
<1003
NA2
<2.2 to 3003
6.0-69.0, usually <25.03
1 ND - not determined
2 NA - not applicable; feed water concentration below action level
3 Data taken from the passive reactor testing completed in November 2004
17
-------
Table 2-2. Field Test - Standards, Feed Concentrations, Effluent Levels, and MDLs
Contaminant
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Zinc
Action Level
WQB-7
Standards
(MS/L)
10
0.76
30.5
300
18.6
50
388
Untreated
Susie Mine
Discharge
(Hg/L)
23,300
241
69.7
228,000
3.8
20,500
50,200
10/03/06
Treatment System
Effluent
Oig/L)
51.9
0.53
BDL
375
0.149
680
24.3
MDL
(Hg/L)
0.5
0.1
2.0
15
0.1
5.0
10.0
BDL = below detection limits
Table 2-3. Effluent Data
Contaminant
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Zinc
Number of
Samples
25
5
5
5
5
5
25
Average
Oig/L)
248
1.67
2.51
942
0.45
785
130.7
Standard
Deviation
Gig/L)
195
1.47
1.27
739
0.41
700
184.4
Maximum
(Hg/L)
680
3.40
4.70
1780
0.97
1520
816.0
Minimum
(Hg/L)
38
0.15
1.43
83
0.13
17
2.5
Note: To calculate average and standard deviation, the instrumentation detection limit was used for non-detect
samples
Table 2-4. Contaminant Loading Reduction to Tenmile Creek
Contaminant
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Zinc
Untreated
Susie Mine
Discharge
(Hg/L)
23,300
241
69.7
228,000
3.8
20,500
50,200
10/03/06
Treatment System
Effluent
(MS/L)
51.9
0.53
<2.0
375
0.149
680
24.3
Quantity Removed
during Demonstration
(pounds)
14.2
0.15
0.04
139
0.002
12.1
30.6
Extrapolated Removal
(pounds/year)
408
4.22
1.2
3993
0.06
348
880
18
-------
Table 2-5. Estimated Annual Reagent Costs
Reagent
Ca(OH)2
Polymer
Sulfuric Acid
GFH Media
Total Annual Reagent Costs to treat 5 gpm
Unit
ton
pounds
ton
pounds
S/Unit
$95.00
$2.25
$116.00
$3.50
Amount
Required
3.8
100
20
1,318
Cost of Reagents
$365
$225
$2,340
$4,614
$7,544
Table 2-6. Water Model Capital Cost Breakdown
Cost Component
Excavation and Site Work
Manufactured Equipment
Concrete
Labor
Pipes and Valves
Electrical
Housing*
Subtotal
Contingencies
Total (2000)
Total (Adjusted to 2004)
Cost Breakdown
$3,500
$44,900
$1,000
$14,700
$8,300
$4,500
$18,600
$95,500
$14,300
$109,800
$120,780
Percentage Breakdown
3.19%
40.89%
0.91%
13.39%
7.56%
4.10%
16.94%
13.02%
100.00%
' Housing costs are added to the total capital cost after application of the TDP cost approach.
Table 2-7. Annual Operational Cost Estimate
Cost Component
Cost Breakdown
Labor (operator hours)
Labor (engineer)
Analytical
Energy
Training
Total
$10,000
$5,000
$2,000
$4,000
$2,000
$23,000
Table 2-8. Annual Disposal Cost for Solid Waste Material
Cost Component
Ferric Hydroxide Sludge
GFH Media
Total
Amount (pounds)
9,554
1,318
Cost Breakdown
$4,800
$650
$5,450
19
-------
3. Conclusions and Recommendations
The primary recommendation from this field study
is the continued operation and maintenance of the
Reductive Precipitation Process implemented by
the MWTP at the Susie Mine. It is also
recommended that the process be optimized
further and that a polishing step be implemented to
clean the water to WQB-7 action level standards.
While the treatment process did not achieve
WQB-7 action level standards for water treated
under this field study, it removed a substantial
quantity of contamination from the mine effluent.
Continued operation will ensure that future water
emanating from the Susie Mine and entering
Tenmile Creek will have a much reduced
contaminant load. EPA Region 8 plans to run the
current process for an additional six to twelve
months and share data with the MWTP.
There is enough design capacity in the Susie Mine
treatment system to accommodate additional flow.
After the existing process issues are resolved,
another mine water, such as the Lee Mountain
Mine discharge, could be fed to the Susie Mine
treatment system.
In order to further improve and speed up the
treatment process, settlers capable of enhanced
solids separation are recommended. The slow
settling time in the field turned out to be the
primary bottleneck in the system, reducing the
flow at times, and preventing process
optimization. Taller settlers with greater volumes
would improve this portion of the process. This
recommendation has been communicated to EPA
Region 8 and COM.
The preliminary economic analysis indicated that
the Reductive Precipitation Process, as
implemented at the Susie Mine, could be an
economical option for treatment of ARD.
Implementation at other mines depends on
numerous factors including: availability of power,
access to mine workings, and mine discharge
characteristics.
This process obviously has much merit, and it is
recommended that it be implemented at mines
throughout Montana and the western United States
that have similar characteristics to the Susie Mine.
Lessons learned during the Susie Mine
demonstration would be beneficial if this
technology were transferred to other mines.
20
-------
4. References
CDM Federal Programs Corp., Acid Mine
Drainage Study, 2001-2002 Data Summary Report
and Loading Analysis, Upper Tenmile Creek
Mining Area Site, U.S. EPA Contract No. 68-W5-
0022, March 2003.
Fendorf, S.M., J. Eick, P.R. Grossl, D.L. Sparks,
"Arsenate and Chromate Retention Mechanisms
on Goethite, I Surface Structure," Env. Sci. and
Technol, 31, pp.315-320, 1997.
Jambor J., J. Dutrizac, "Occurrence and constitution
of natural and synthetic ferrihydrite, a widespread
iron oxyhydroxide," Chemical Review, pp. 2549-
85,1998.
Manceau, A., "The Mechanism of Anion
Adsorption on Iron Oxides: Evidence for the
Bonding of Arsenate Tetrahedra on Free
Fe(O,OH)6 Edges," Geochimica et Cosmochimica
Acta, 59, pp. 3647-3653, 1995.
Masscheleyn, P.H., R.D. Delaune, and W.H.
Patrick, Jr., "Effect of redox potential and pH on
arsenic speciation and solubility in a contaminated
soil," Environmental Science and Technology, v.
25, pp.1414-1419, 1991.
Montana Department of Environmental Quality,
Montana Numeric Water Quality Standards,
Circular WQB-7, January 2004.
MSE Technology Applications, Inc., Mine Waste
Technology Program, Quality Assurance Project
Plan - Physical Solutions for Acid Mine Drainage
at Remote Sites Demonstration Project, Activity
III, Project 42, October 2006.
MSE Technology Applications, Inc., Mine Waste
Technology Program, Health and Safety Plan for
the Installation and Operation of the Susie Mine
Water Treatment System in Rimini, Montana,
Activity III, Project 42, April 2006.
MSE Technology Applications, Inc., U.S.
Environmental Protection Agency, Mine Waste
Technology Program, Interim Report - Physical
Solutions for Acid Mine Drainage at Remote Sites,
Phase I, Document number MWTP-271, February
2006.
Nishimura, T., Y. Umetsu, "Chemistry on
Elimination of Arsenic, Antimony and Selenium
from Aqueous Solutions with Iron (III) Species,"
In: Minor Metals 2000, Ed. C. A. Young, SME,
Littleton CO, pp. 105-112, 2000.
Nishimura, T., R.G. Robins, L.G. Twidwell,
"Removal of Arsenic from Hydrometallurgical
Process and Effluent Streams," Proceedings V
International Conference on Clean Technologies
for the Mining Industry. Santiago, Chile, May 9-
13, 2000, Vol. I, Waste Treatment and
Environmental Impact in the Mining Industry,
pp.131-141.
Robins R.G., "The Stability of Arsenic in Gold
Mine Processing Wastes," Precious Metals, Eds.:
V. Kydryk, D.A. Corrigan, W.W. Liang, TMS-
AIMS, Warrendale, PA, pp. 241-249, 1984.
Sun, X., H.E. Doner, "An Investigation of
Arsenate and Arsenite Bonding Structures on
Goethite by FTIR," Soil Science, 161, pp. 865-
872, 1996.
U.S. Environmental Protection Agency, "First
Five-Year Review Report for Upper Tenmile Creek
NPLSite", July 2008.
http://www.epa.gov/region8/superfund/mt/upper_t
en/1 OmileRevisedFinal3 0 Jul08 .pdf
U.S. Environmental Protection Agency,
"Technologies and Costs for Removal of Arsenic
from Drinking Water", EPA 815-R-00-028,
December 2000.
21
-------
USGS, Geochemistry of Arsenic, Arsenic in Waychunas, G.A., Davis, J.A., and Fuller, C.C.,
Ground Water of the Willamette Basin, Oregon, "Geometry of sorbed arsenate on ferrihydrite and
2001. http://or.water.usgs.gov/pubs_dir/ crystalline FeOOH: Re-evaluation of EXAFS
Online/Html/WRIR98-4205/as_report6.html results and topological factors in predicting
sorbate geometry, and evidence for monodentate
Waychunas, G.A., B.A. Rea, C.C. Fuler, J.A. complexes." Geochem Cosmochim Acta 59, 3655-
Davis, "Surface Chemistry of Ferrihydrite: I 3661, 1995.
EXAFS Studies of the Geometry of Coprecipitated
and Adsorbed Arsenate," Geochimica et
Cosmochimica Acta, 57, pp. 2251-2269, 1993.
22
-------
APPENDIX A
Technical Review Meeting - Phase I
Attendance Sheet
-------
RIMINI SITE MEETING
JUNE 2, 2004
Name
Jay McCloskey
Kami Mainzhausen
Kent Whiting
Darre! Slordahl
Diana Bless
Gene Ashby
Roger Wilmoth
Mike Bishop
Helen Joyce
Neil Marsh
Lynn McCloskey
Vic Andersen
Keith Large
John Trudnowski
Company
MSB
COM
COM
CDM
U.S. EPA
U.S. DOE
U.S. EPA
EPA -
MSB
CDM
MSB
MDEQ
MDEQ
MSB
Phone
406-494-7262
406-449-2121
406-449-2121
406-449-212!
513-569-7674
406-494-7298
513-569-7509
406-457-5041
406-494-7232
406-495-1414 £'fot-
406-494-7371
406-841-5025
406-841-5039
406-494-7220
E-Mail
jmcclosk@mse-ta.com
mainzhausenk@cclm.com
whitingks@cdm.com
stordahldm@cdm.com
bless.diana@ej3a.gov
gashby@in-tch.com
wilmoth.roger@epa.gov
bishop.mike@epa.gov
hojoyce@mse-ta.com
marshna@cdm.com
lmcclosk@mse-ta.com
vandersen@state.nit. us
klarge@state.mt.us
jolmt@mse-ta.com
A-l
-------
APPENDIX B
Historical Data for Susie Mine Discharge
-------
Table B-l. Historical data of Susie Mine discharge.
Project Water
Sample Date
Analyte
Aluminum
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Selenium
Thallium
Zinc
PH
ORP
Unit
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
|ig/L
Mg/L
Mg/L
Mg/L
Mg/L
SU
mV
Susie/Valley Forge
10/10/2002
Total
760
4.2
8,280
1.0
200
1.1
59
48
119,000
4.9
105,000
13,400
0.10
37
14
5.3
28,400
4.5
170
From COM report, 2003
B-l
-------
APPENDIX C
Reductive Precipitation Process
Process Flow Diagram
and
Process General Layout in Susie Mine
and
Piping and Instrumentation Diagram
-------
,-£—I
-ff
AH 0
L-u—rW^
** ia
D
D
i
e
I
(J
3
I
N^ v If 1 - j -. 3,
t t. *u 0] h
P t , i ^ L 3 i T.
X- " j i -
•s 1 !"> T_,L
1
t CtE
7
[ p-
t
J
U Uf
"30
298
j-l
T CT -tt
'
! "
* - l-r^r- ^ F r^
-
L I l
j
1 * "
\
\ l
, » ' '
L * L L
I ,
1 J
1 ' J 1
1 ' i ^' !
J. ^ ,1
j»
tr
M -
^ i
1 i
1
'
'
j
ut * (. l ^ 15 "M.-M 3
j f n D- - i » 10, EL PHL Tdi jf.t.s erl - s * J ",,
•> t T * JX i eJ HD
t 1 s _ L ' L L ^ L 1? idp J,V * 3,
t ' 1 " -"4 ' 1 ' 'fill. J
] PC Pit fi
U* U L:!| i *• 1A Ct«Jj!>
35 1 ti' 8 0 i T d 3y j 1 «1
•SS CM 171 j 3 EF 4 T ! t jPjTir
; TA, INC.
CAD |
-------
9 I 10 I 11 I P I 13 I 14 I 15 I 16
14 | 15 | 16
-------
10
12
13
1t
DRAWING NUMBERI DESCRIPTION
REFERENCES
T I I I I I
12
16
-------
10
13
14
15
3 ELEVATION HENCIMARK " 10QJQQ (A83lJhB3)
QE8CRFTION: BRASS CAP CORNER MARKED: TBf. ML1-171B, 1711SUSE'
PROFILE IS E&TMATED IN THIS AREA
(CM8T1WO)
ELEVATION VIEW
OWN LINE
(SEE CONSTRUCTION NOTES)
DUum tni LmgUi an ±
Etowrton. era ±0.10 tea
Rimini Adit and Room Opening Information
OHmrticlion Notes:
I. Contractor shall provide u temporary piping system or olh
filter flow from the dam located in the Adit to the present drain piping
located unhide of the Atfil during i-cmKtrltction »nil until the permanent
piping *v*tem vh^nn on fhi* dni»ing is compk'te. 1 lie cMtnisiIet! do» niteof
the HHU'r nonin^ from the dsiiti to the oulsidc dr^in b 5 gitllunH per minuti'.
monitwring «f ventilation of the Adit to OSHA Mandards, toilet faeilities,
potable uater a* reijiiireU anil construction power throughout con^truelion.
^. Contractor is responsible for any res|ifire(i snow removal, ^radin» or sanding
of entrance nmd to facilitate const ruction aeliv ities.
4. Permanent piping shall )>e supplied and instiillfd in accordance nirh the
contract specifications ami contract Drawing No. l«>t-«]PI>-l«>2
5, A miniraum or2-inchet thick AIM (road mil) material shall be niacetl and
compai-tet! in all areas that will he concreted anil adjacent to areas to he
concreted as indicated on 111 is drawii*£.
6. All floor areas that are not scheduled to have concrete placed shall he
backfilled vtith 9A-inch to 1-inch vuishcd gravel »ith no fines. These areas
this contract.
1- " 1.0.C." stands for eles ation at the "top of concrete".
MSEWILL PROVIDE ALL LABORAND MATERIAL
FOR ELECTRICAL BOND. CONTRACTOR 18 REQUIRED
TO PROVIDE 24 HOUR NOTICE TO MSEWHEN
INSTALLATION OF WIRE MESH IB COMPLETE.
:ans to allim
MN-PLACE CONCRETE WALKWAY
l-TOI-WASrEmOCKfTYFEM)
TO ACHT WALL£ (TYP) AND TO
ELEVATION OF ADJACENT CONCRETE WALKWAY
WBXa-D&XBFLAT SHEET
WELDED WIRE MESH
(TYP) ALL AREAS
HO MINE ADIT ROCK FLOOR
TYPE ABC (ROADMX) MATERIAL
0 CPVC PIPE PLACED ON ESSTNO ROCK FLOOR
(SEE CONSTRUCTION NOTES)
AT 119 DISTANCE FROM PORTHOLE
(TYP]
SCALE: 1'=1r
NOTES:
1. AREA OF ROOM BETWEEN Tff LINE AND 12S LHE B 1,337.8 « *.
2. PERNETER OF SAME AREA IS 147.6-,
i. AREA OF MIE BETWEEN -V LINE AM> 19ff LME 132021/ttl1.
4. PERIMETER OF SAME AREA B S&-ST
'III
RGHHB
-------
j I
J in I 11 I IT I 13 I H I 15 I
-J-
UAJtEUPTAMK
T.1PI
(12SBAL.)
LJME SlURBY TAMK
TJBi
(MOGUL)
fLOCTANK
im.
|*M«M.)
MIKREACTQBTmK
(«l OAL)
REJUSEHT yHPUMP F1RROUSMLUTXIH
IDBAIHNC NUMBER
1 T
1 7 I I I I I T I I I I I 10 | fl | 12 I 13 |
| 15 1 16
-------
SUIT URIC ACID BACKWASH CAPTURE TANK
T-105
(53 SAL.J (SOQ QAL)
NOTES:
1. SLUDGE HOLD TANKS T-311 THRU T-313 AND ASSOCIATED PIPING IS FOR FUTURE INSTALLATION.
A FILTER PRESS WILL BE INSTALLED INITIALLY.
16
-------
APPENDIX D
Simulation Model for Reductive Precipitation Process
-------
COAGULATION/ PRECIPITATION MODEL (Confidential): VERSION 7/18/05
Liquid ^^^^^~
Composition. moA
— Galjhiin Litjmin As Fe SO4 Cd
JUIIj ...... .™... -, ,, , , u „ Ji.-j ,u._ , ^u.u P_^._. u.i-r-j
Causti
* «a oooo oo o.o DO o
Total 10.0 37.9 10.9 150.0 152.0 0.243
c or • To Inputs Ferric, mg/L 55
(If needed) FERRIC FEED RATE (If needed)
r^nr F°2(Qn4)q in F°°d q.'l
PRECiPITATION '' Lime ^"l««on Required addition, ml/min
REACTOR pH= 6.5 Total Ferric, mg/L.
| Fk
I Ferrous Solution
1 / '"lurr-^cnc ™t " 'L
1 1r^ " " /"• From Sand '
fc SETTLER NO. ONE 1" / Filters Backflush
/ Flowsheet 2 HYDRATED LIME FEED RATE
\ / / T0 PRECIPATION REACTOR
\ / , ^v *«>
Tank Y^ Mlx SETTLER NUMBER ONE
w / Rea=tor PH- 8 Solids Accumulation, IDS
As
4
Solids, %
25
t
20
TOTAL SLUDGE
Ibs/day
ton/yr
1 f / Days for Accumulation
] f. Solids
i cj 200 gal Required addition, ml/min
SLUDGE \ HYDRATED LIME FEED RATE
TANK Miy Boar-tnr slurry ml/min
To Settler One Mi< Reactori jipj,-,,, rng/mm
SETTLER NUMBER TWO
Solids Accumulation, Ibs
Days for Accumulation
| Solids
1 FILTER PRESS Solution, ug/L
FILTER CAKE
Filter Press So|ids m R||er Cak^ %
Solills Solids, Ibs
Solution, Ibs
^ Solution for Recycle, L
Filter Cake Soiids Composition
TOTAL SLUDGE
,% Fe Cd Cu Ni Pb Zn Al Ibs/day
.9 42.6 0.1 0.0 0.0 0.0 1.7 0.3 tons/day
tons/yr
Solution in Filter Cake Composition, ugJL
M: Fe Cd Cu Ni Pb Zn Al
)0.2 46958.5 0.0 0.0 62.7 4.0 11874.0 102.2
142.7
26.0
0
240.6
1DD
0,27
55.1
43.57
4345,56
430,9
29.2
77,0
2.7
20.3
As
12.1
3954.0
300
60
76.8
76850
Note:
Fe(IM)/As wt ratio must always be >1.12
Fe(lll)/As mole ratio must always be >1.5
In this case: Fe(lll)/As wl ratio= 2.91
Fe Cd
0.0 0.2
94189.5 0.0
37ml
Cu Mo Pb Zn
0.1 0.1 0.0 4.8
0.0 62.6 4.0 23482.8
TOTAL HYDRATED LIME SLURRY FEED RATE
ml/mm 12042
mg/min 12030.52
956.3
29.2
As Fe Cd
1.6 61.8 0.0
104.9 2744.4 00
25
1387,2
4161.7
4717.8
1427
0.071
260
Mo
00
62.9
Pb Zn
0.0 0.3
4.0 12.9
-------
APPENDIX E
Independent Technical Review
Attendance Sheet
-------
LEVEL C DESIGN REVIEW
FOR
PHYSICAL SOLUTIONS FOR ACID MINE DRAINAGE AT REMOTE MINE
SITES DEMONSTRATION PROECT
<*•
ATTENDANCE SHEET
NAME
DIVISION
'>
PHONE #
O
74-1 f
/'/f £*«/-' '
4 ineciy m&,
(/ /7'
E-l
-------
APPENDIX F
Summary of Quality Assurance Activities
-------
Summary of Quality Assurance Activities
Mine Waste Technology Program
Activity III, Project 42
(Physical Solutions for Acid Rock Drainage at Remote Sites)
F.I BACKGROUND
The following is a summary of the Quality Assurance (QA) activities associated with MWTP Activity III,
Project 42, Physical Solutions for Acid Rock Drainage at Remote Sites Demonstration Project.
Analytical samples and field data were collected according to the schedule outlined in the approved
project-specific quality assurance project plan (QAPP) document. All field and laboratory data available
has been evaluated to determine the usability of the data. Data from both critical and noncritical analyses
were evaluated. Critical analyses are analyses that must be performed to determine if project objectives
were achieved, while noncritical analyses provide additional information about process control, as well as
information that is of interest to project participants. The critical parameters, total arsenic and zinc, were
analyzed to support the project objective of determining if the Reductive Precipitation Process could
effectively remove arsenic and heavy metals to below the Montana Circular WQB-7 Standards.
F.2 PROJECT REVIEWS
An external technical systems audit (TSA) of project field activities and MSB Laboratory was performed
by David Gratson of Neptune and Company (subcontractor to EPA) on September 19 and 20, 2006.
There were no findings, ten observations, and no additional technical comments identified during the
audit.
On September 19, the analytical activities at MSB Laboratory were reviewed. The observations regarding
the laboratory audit included improving sensitivity for metals analysis, toxicity characteristic leaching
procedure (TCLP) preparation modifications, SOP modification for sample receipt temperature, and data
validation requirements. Appropriate amendments were made and implemented to correct the
observations presented in the report. To improve sensitivity for metals analysis, particularly arsenic,
cadmium, and lead, MSB Laboratory utilized ICP-MS method 6020, when appropriate, and used EPA
Method 200.2 for digestion. The TCLP preparation modifications included discontinuing use of
hydrogen peroxide reagent in the TCLP extract preparation, and ensuring that filtration of TCLP solids
other than vacuum filtration would be documented. The SOP pertaining to sample receipt (GP005) was
amended to include criterion and action for sample temperatures taken during receipt. The data validation
requirements in the QAPP were clarified so that Contract Laboratory Program guidelines for inorganic
data review would be applied for data validation although EPA SW-846 methods were being used.
On September 20, the field activities at the Susie Mine in Rimini, Montana were reviewed. The
observations pertaining to the field audit included updating the operating and maintenance (O&M)
manual, system flow rate modifications, daily oxidation-reduction potential (ORP) calibration, including
sampler's initials on sample labels, and verification of sample preservation. Appropriate amendments
were made and implemented to correct the observations. The O&M manual was updated to include
additional details on daily checks, corrective actions, sampling, and monitoring. To monitor system flow
rates, a process effluent flow totalizer was installed, because only the influent flow was being monitored.
Also, the use of flow meters in the system was documented. The O&M manual indicated that the ORP
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electrode was to be calibrated weekly, while the QAPP specified a daily calibration. The O&M manual
was edited to include a daily ORP calibration. The prepared sample labels did not include a place for
sampler's initials, so new sample labels were prepared to include sampler information. Because some of
the samples from the system were anticipated to have a high pH, no means were available to ensure that
the acid was lowering the pH to < 2. Verification of pH in the field by using pH paper or a handheld pH
probe was implemented.
F.3 DATA EVALUATION
Data that was generated throughout the project was validated. The purpose of data validation is to
determine the usability of data generated during a project. Data validation consists of two separate
evaluations: an analytical evaluation and a program evaluation. The analytical evaluation focuses on
laboratory data validation, field logbook evaluation, and field data evaluation, while the program
evaluation concentrates on chain-of custody procedures, sampling and data completeness, and field
quality control (QC) samples.
F.3.1 Analytical Evaluation
An analytical evaluation of all data was performed to determine the usability of the data that was
generated by MSB Laboratory for the project.
F.3.1.1 Laboratory Data Validation
Laboratory data validation was performed using USEPA Contract Laboratory Program National
Functional Guidelines for Inorganic Data Review (OSWER 9240.1-45, EPA540-R-04-004, October
2004) as a guide. The data quality indicator objectives for critical measurements were outlined in the
project QAPP and were compatible with project objectives and the methods of determination being used.
The data quality indicator objectives were method detection limits (MDLs), accuracy, precision, and
completeness. Control limits for each of these objectives are summarized in Table F-l. In addition to the
data quality indicators listed in Table F-l, internal QC checks, including calibration, calibration
verification checks, calibration blanks, matrix spike duplicates, interference checks, method blanks, and
laboratory control samples were used to identify outlier data and to determine the usability of the data for
each analysis.
Measurements that fell outside of the control limits specified in the QAPP or method requirements, or for
other reasons were judged to be outlier, were flagged appropriately to indicate that the data was judged to
be estimated or unusable. All data requiring flags are summarized in Table F-2.
For part of the project, MSB Laboratory used influent samples for QC. The spiking levels were not
appropriate for arsenic and zinc. The influent concentration of arsenic ranged from 400-500 times greater
than the spike concentration of 40 |o,g/L, while the influent concentration of zinc ranged from 60-80 times
greater than the spike concentration of 500 |og/L. Because the sample concentrations for arsenic and zinc
were greater than four times the spike concentrations, the recovery limits were not applicable. It was
requested that for future data sets, MSB Laboratory should use different sample locations other than the
feed water for spike analysis (per Memorandum issued 12/15/2006). Serial dilution results were deemed
outlier in a few instances, but were never outlier for the critical parameters. Serial dilutions were within
acceptable limits for arsenic and zinc, which indicates that there were no significant matrix effects.
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F.3.1.2 Field Logbook Evaluation
Field data validation began with an examination of the field and sampling logbooks that were generated
for this project. The general logbook contained daily logs of safety inspections, process evaluations, and
operation and maintenance work performed on the process. The sampling logbook contained all
information for sample collection and field measurements that were taken. Sample dates and times,
sample identification, sampling personnel, pH, ORP and temperature measurements, and comments were
documented in the logbook for each sampling event. A daily log sheet was also used to document
treatment system information including flow totalizer readings, system pH readings, and reagent tank
level measurements. Not all sampling measurements were documented for each sampling event. The
missing field measurements will be further discussed.
F.3.1.3 Field Data Evaluation
Field data validation was performed to determine the usability of the data generated during field activities.
Usability was determined by verifying that correct calibration procedures on field instruments were
followed. All of the field measurements for this project were classified as non-critical.
Measurement of pH was performed manually using a hand-held probe. The pH meters had automatic
temperature compensation and were capable of measuring pH at the demonstration site to ± 0.1 pH units.
The hand-held probe was calibrated daily prior to analysis using pH 7 and 10 buffer solutions. In-line pH
probes were also installed to automatically control process pH. The pH from the in-line probes was also
reported on the daily process log sheet. Calibration of the in-line probes was performed daily prior to
analysis using the same buffer solutions. The in-line pH readings were compared to the hand-held pH
readings to verify that the readings were consistent.
The QAPP required recording of daily pH measurements for all sampling locations. In several instances,
a pH measurement was not recorded in the field or sampling logbook. In most cases, an explanation of
the omission was included (i.e., broken/unavailable probe or dead batteries). Missing pH data resulted in
a percent completeness of 8 1 .4%, which was lower than the 90% target.
ORP
An ORP meter with a silver/silver chloride reference electrode will be used to determine the ORP at the
demonstration site. The electrode was calibrated at the beginning of every sampling event using the
manufacturer's instructions and a solution with known ORP. The measured standard ORP was not
documented, so it is not known if the ORP was within ± 20% of the known value.
The QAPP required daily ORP measurements for all sampling locations. In several instances, an ORP
measurement was not recorded in the field or sampling logbook. In most cases, an explanation of the
omission was included (i.e., broken/unavailable probe or dead batteries). The missing ORP data resulted
in a percent completeness of 70%, which was lower than the 90% target.
Temperature
Water temperature was measured using the thermistor in the hand-held pH meter.
The QAPP required a daily temperature measurement for all sampling locations. In several instances, a
temperature measurement was not recorded in the field or sampling logbook. In most cases, an
explanation of the omission was included (i.e., broken/unavailable probe or dead batteries). Missing
temperature data resulted in a percent completeness of 70.5%, which was lower than the 90% target.
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Flow Rate/Total Flow
A flowmeter with a totalizer was used to monitor flow into the system. The flow totalizer monitored the
total flow in and out of the system. The flowmeters and totalizers were factory calibrated. The QAPP
required daily measurements of flow rate and total flow for flow in and out of the system. Flow rate and
total flow measurements were recorded on the daily log sheet. Flows and system readings were not
recorded during the commissioning period because it was not being treated at that time. Readings were
initiated following system startup.
F.3.2 Program Evaluation
Program evaluations included an examination of data generated during the project to determine that all
field QC checks were performed and within acceptable tolerances. Program data that was inconsistent or
incomplete and did not meet the QC objectives outlined in the QAPP were viewed as program outliers,
flagged appropriately to indicate the usability of the data, and are summarized in Table F-2.
F.3.2.1 Chain-of-Custody Procedures
Information provided on the chain-of-custody was accurate and complete, and any discrepancies noted by
MSB Laboratory were communicated to the project manager and resolved through laboratory corrective
action procedures.
F.3.2.2 Sampling and Data Completeness
Due to budget constraints, not all samples that were planned to be collected were collected. In some
instances, certain sample sites were omitted from the daily sampling, and the samples were not taken at
the frequency specified in Table 1-5 of the QAPP. Also, some of the required field measurements were
not documented in sampling log sheets. In most cases, there was a documented explanation of why
measurements were omitted, but in some instances, there was no indication as to why parameters were
absent.
F.3.2.3 Field QC Samples
In addition to internal laboratory checks, field QC samples were collected to determine overall project
performance. All field QC samples were collected at the proper frequency for tests specified in the
QAPP. Any samples requiring qualification due to field QC samples are summarized in Table F-2. None
of the field blanks collected for the project showed significant contamination, with one exception. A field
blank collected November 3, 2006 (SP-108), did show significant contamination for total calcium,
copper, and magnesium. As a result, total calcium, copper, and magnesium values for affected samples
received a "J" flag. However, the field blank results for the critical parameters remained under the
contract required quantitation limit (CRQL). Field duplicates showed very good agreement to the original
sample, with one exception. A field duplicate sampled January 16, 2007 (SP-109), was out of control for
arsenic and zinc, resulting in the associated samples to be flagged "J" for arsenic and zinc values.
F.4 SUMMARY
MWTP, Activity III, Project 42 provided data for twelve weeks of system operation and testing. While
findings were discovered during program and analytical evaluations, none of the critical data was rejected
during the data evaluation and validation process.
Several lessons can be learned from this project to improve future project quality assurance/quality
control (QA/QC). The biggest issue was that the field logbook disappeared after all field and sampling
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activities were completed, and was not available for the final report. Although field log sheets were used
to collect specific data during sampling events, critical activities are usually documented in the field
logbooks. Better management of such an important part of the project is critical. Also, information
provided in the logbook and log sheets needs to be expanded and better organized so that anyone
reviewing the logbook can clearly understand what occurred at each sampling event. The importance of
logbook protocol should be reiterated to sampling personnel. Better planning and training of sampling
personnel could improve the completeness percentage of data collection, and ensure that all parameters
are documented. Proper training of sampling procedures prior to sampling events could eliminate field
QA/QC discrepancies, and ensure good representativeness and comparability.
Table F-l. Data Quality Indicator Objectives For Precision, Accuracy, MDL, and Completeness
Parameter Matrix Unit MDLa Precision1" Accuracy0 Completeness*1
Total As Aqueous |ig/L 0.5 <20% 75-125% 90%
Total Zn Aqueous |ig/L 10.0 <20% 75-125% 90%
a MDLs are based on what is achievable by the methods, and what is necessary to achieve project objectives and account for
anticipated dilutions to eliminate matrix interferences. MDLs will be adjusted as necessary when dilutions of concentrated
samples are required.
b Relative percent difference (RPD) of analytical sample duplicates.
0 Percent recovery of matrix spike, unless otherwise indicated.
d Based on number of valid measurements, compared to the total number of samples.
Table F-2. Summary of Flagged Data for Activity III, Project 42
Date of
Collection
9/26/2006
10/3/2006
11/3/2006
11/3/2006
11/3/2006
Sample ID
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
Analysis
Total Ca and Fe
Total Al and
Mn
Total Cd
Total and
Dissolved Pb
Total Ca, Cu,
andMg
Quality Criteria
+10% difference of original
determination for serial
dilution analysis if analyte
concentration is >50 times
the MDL.
+10% difference of original
determination for serial
dilution analysis if analyte
concentration is >50 times
the MDL.
+10% difference of original
determination for serial
dilution analysis if analyte
concentration is >50 times
the MDL.
75%-125% spike recovery
Blank concentration >
CRQL; sample
concentration < 10* CRQL
Flag Comment
J Serial dilution percent difference
was 11.2% and 11.4% for Ca and
Fe, respectively. The associated
samples should be flagged J for
total Ca and Fe.
J Serial dilution percent difference
was 27.1% and 36.4% for Al and
Mn, respectively. The associated
samples should be flagged J for
total Al and Mn.
J Serial dilution percent difference
was 18.2% for Cd. The
associated samples should be
flagged J for total Cd.
J Spike recovery for total Pb was
at 66%, while dissolved Pb spike
recovery was at 62%. The
associated samples should be
flagged J for total and dissolved
Pb.
J The field blank sample showed
significant contamination; the
associated samples should be
flagged J for total Ca, Cu, and
Me.
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Date of
Collection
1/16/2007
1/17/2007
1/18/2007
1/26/2007
Sample ID
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
SP-101
SP-103
SP-105
SP-107
Analysis Quality Criteria
Total As and Zn <20%RPD
Dissolved Mg +10% difference of original
determination for serial
dilution analysis if analyte
concentration is >50 times
theMDL.
Dissolved Mg +10% difference of original
determination for serial
dilution analysis if analyte
concentration is >50 times
theMDL.
Dissolved Mg +10% difference of original
determination for serial
dilution analysis if analyte
concentration is >50 times
theMDL.
Flag Comment
J Field duplicate RPD was 83. 5%
and 74.6% for As and Zn,
respectively; the associated
samples should be flagged for
total As and Zn.
J Serial dilution percent difference
was 17.7% for Mg. The
associated samples should be
flagged for total Mg.
J Serial dilution percent difference
was 17.7% for Mg. The
associated samples should be
flagged for total Mg.
J Serial dilution percent difference
was 17.7% for Mg. The
associated samples should be
flagged for total Mg.
Data Qualifier Definition:
J—The measurements are estimated.
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