EPA/600/R-08/095
July 2008
Mine Waste Technology Program
Electrochemical Tailings Cover
By:
Diane Jordan
MSB Technology Applications, Inc.
Mike Mansfield Advanced Technology Center
Butte, Montana 59702
Under Contract No. DE-AC09-96EW96405
Through EPA lAGNo. DW8993989701-0
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 groundwater; 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 EPA and
administered by the U.S. Department of Energy (DOE) 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 (MWTP) Activity III, Project 40,
Electrochemical Tailings Cover, funded by the U.S. Environmental Protection Agency (EPA) and jointly
administered by EPA and the U.S. Department of Energy (DOE). MSE Technology Applications, Inc.
implemented the technology demonstration for EPA and DOE. This project addressed EPA's technical
issue of Mobile Toxic Constituents - Water and Acid Generation.
The objective of Project 40 was to demonstrate the effectiveness of an electrochemical enhancement of
conventional soil covers to inhibit the oxidation of sulfide minerals in mine waste to control generation of
acid mine drainage. ENPAR Technologies, Inc. of Guelph Ontario, Canada, was the technology provider
for trademarked electrochemical cover AmdEI™, which is an alternative to conventional earthen covers
for decommissioning and long-term management of deposits of mill tailings and mine waste rock
containing acid-generating sulfide minerals.
This demonstration showed evidence that the electrochemical tailings cover could reduce the oxidation of
sulfide minerals in sulfide-containing mine waste. The reduction in oxidation of sulfur in the tailings was
best shown by the post-test ABA analysis. The electrochemically treated cells retain total sulfur and
pyritic sulfur at significantly higher levels than in the control cells that had no special treatment. In fact,
treatment cell T2 retained over 90% of its original sulfur content. Nearly 50% of the sulfur was retained
in the other treatment cell, Tl; however, there was a large degree of variation in the initial sulfur data for
this treatment cell, which seemed somewhat suspect due to high total sulfur content when compared to the
three other test cells. Interestingly, both cells with the electrochemical treatment retained about 4.5%
total sulfur while the untreated cells contained less than 0.05% sulfur at the conclusion of the
demonstration. It is apparent that the sulfur was readily oxidized and leached away from the top few
inches of tailings in the untreated control cells since initial total sulfur in the cells ranged from 4.78% to
9.44%.
IV
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Contents
Page
Disclaimer ii
Foreword iii
Abstract iv
Contents v
Figures vii
Tables vii
Acronyms and Abbreviations viii
Acknowledgments ix
Executive Summary ES-1
1. INTRODUCTION 1
1.1 Project Description 1
1.2 Purpose 1
1.3 Project Schedule 1
1.4 Report Structure 2
2. DEMONSTRATION PARTICIPANTS AND RESPONSIBILITIES 3
2.1 Demonstration Participants 3
2.2 Responsibilities 3
2.2.1 MSE Technology Applications 3
2.2.2 Developers 3
3. PREDEMONSTRATION ACTIVITIES 4
3.1 Site Selection 4
3.2 Regulatory Plans and Classifications 4
3.2.1 Hazards Classification 4
3.2.2 Quality Assurance Project Plan 4
3.2.3 Analytical Laboratory 4
4. DEMONSTRATION INSTALLATION DESCRIPTION AND DESIGN 5
5. DEMONSTRATION TECHNOLOGY DESCRIPTION 11
6. EXPERIMENTAL DESIGN 12
6.1 Technology Demonstration Objectives 12
6.2 Factors Considered 12
6.3 Installation Tailings Characterization 12
6.3.1 Acid-Base Accounting 12
6.4 Sampling Design 12
6.5 Monitoring Phase Measurements 12
6.5.1 Electrochemical Measurements 12
6.5.2 Sulfate and pH Measurements 12
6.5.3 Dissolved Metals 13
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Contents (Cont'd)
Page
6.6 Completion Phase Measurements 13
6.6.1 Acid-Base Accounting 13
6.6.2 1:1 pH 13
6.7 Statistical Analysis 13
7. FIELD SAMPLING AND ANALYSIS 16
7.1 Techniques and Methods 16
7.2 Field Sample Analysis and Data Recording 16
7.3 Instrument Accuracy 16
8. DISCUSSION 18
8.1 Field Installation 18
8.1.1 Acid-Base Accounting 18
8.1.2 Other Installation Analysis 18
8.2 Monitoring Period Leachate Analyses 18
8.2.1 Voltage and Current Measurements 18
8.2.2 Leachate Analysis 19
8.2.3 Irrigation Water 20
8.3 Post-Demonstration Measurements 20
8.3.1 Acid-Base Accounting 20
8.3.2 1:1 pH 20
9. CONCLUSIONS AND RECOMMENDATIONS 27
9.1 Lessons Learned 27
10. REFERENCES 28
Appendix A: Laboratory and Field Data
A-l
Appendix B: Data Collection Schedule During Field Installation and Monitoring and After Test
Completion B-l
Appendix C: Quality Assurance Activities
C-l
VI
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Figures
Page
4-1. Top view of demonstration installation 7
4-2. Cross-sectional view of cell installation 8
4-3. Cathode mesh in treatment cell Tl 9
4-4. Magnesium anodes 9
4-5. Bentonite beads around test cell outer edge and well pipe 10
4-6. Test cell final configuration September 30, 2003 10
8-1. Water depth in the test cells overtime 21
8-2. Treatment cell Tl voltage and current measurements 21
8-3. Treatment cell T2 voltage and current measurements 22
8-4. Test cell leachate production 22
8-5. Test cell leachate pH 23
8-6. Test cell leachate sulfate 23
8-7. Total sulfate leached from the test cells 24
8-8. Leachate SC 24
Tables
2-1. Demonstration Support and Developer Organizations 3
6-1. Pre-Test and Post-Test ABA Total Sulfur Comparison 15
6-2. Pre-Test and Post-Test ABA Pyritic Sulfur Comparison 15
7-1. Calibration Requirements for Process Field Measurements 17
8-1. Total Metals in Test Cell Leachate 25
8-2. Post-Test Acid-Base Accounting and 1:1 pH Results 26
vn
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Acronyms and Abbreviations
ABA acid-base accounting
AMD acid mine drainage
COC chain-of-custody
DOE U.S. Department of Energy
EPA U.S. Environmental Protection Agency
GSM Golden Sunlight Mine
HOPE high-density polyethylene
MDL method detection limits
MSE MSE Technology Applications, Inc.
MWTP Mine Waste Technology Program
ORP oxidation-reduction potential
QA quality assurance
QAPP quality assurance project plan
QC quality control
SC specific conductance
SOP standard operating procedure
Vlll
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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
wa MSB's MWTP Program Manager. Ms. Diana Bless was the EPA Project Manager, while Ms. Lauren
Drees was the EPA Quality Assurance Officer, for this project.
The following people also contributed significantly to the success of this project:
Gene Shelp, ENPAR
Brian Park, MSE Technology Applications, Inc.
Gary Wyss, MSE Technology Applications, Inc.
Diane Jordan, MSE Technology Applications, Inc.
Dave Sheldon, formerly of MSE Technology Applications, Inc.
Rory Tibbals, Golden Sunlight Mine
Shannon Dunlap, Golden Sunlight Mine
IX
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Executive Summary
The Mine Waste Technology Program (MWTP), Activity III, Project 40, Electrochemical Tailings Cover,
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. MSE Technology
Applications, Inc. implemented the project for EPA and DOE. Project 40 addresses EPA's technical issue
of Mobile Toxic Constituents - Water and Acid Generation.
The ultimate goal of the Electrochemical Tailings Cover project was to demonstrate the effectiveness of
an electrochemical enhancement of conventional soil covers to inhibit the oxidation of sulfide minerals in
sulfide-containing mine waste to control the generation of acid mine drainage (AMD). The technology is
trademarked as AmdEI™ by ENPAR Technologies, Inc. of Guelph, Ontario, Canada, as an alternative to
conventional earthen covers for decommissioning and long-term management of deposits of mill tailings
and mine waste rock containing acid-generating sulfide minerals.
The AmdEI™ electrochemical cover is designed to prevent the influx of oxygen into the sulfide-
containing tailings or other waste materials to inhibit generation of AMD. The effectiveness of the
technology was assessed by monitoring changes in sulfide oxidation (as manifested by sulfate
concentration and pH of leachate samples) that occurs between electrochemically enhanced cells and
identical test cells with no electrochemical enhancement over a 2-year test period. Due to the short test
duration, information regarding longevity of the electrochemical cover was not acquired, and an
economic analysis was not performed because the scale of the demonstration was so small.
Disappointingly, the leachate water samples failed to provide any conclusive evidence about the
effectiveness of the electrochemical tailings cover. No significant trends in leachate sulfate, total sulfate,
or pH could be denoted. The oxidation rate of the sulfur in the tailings may be responsible for the
inconclusive findings from the leachate sulfate and pH. The duration of the demonstration may have been
of insufficient length for the oxidation of sulfide to dominate the leachate chemistry.
ES-1
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1. Introduction
This document is the final report for the Mine
Waste Technology Program (MWTP), Activity III,
Project 40, Electrochemical Tailings Cover
Project. The MWTP is funded by the U.S.
Environmental Protection Agency (EPA) and is
jointly administered by the EPA and the U.S.
Department of Energy (DOE) through an
interagency agreement. MSE Technology
Applications, Inc. (MSE) implements the MWTP
for EPA and DOE. This report details the project
history, preparation, site selection, field testing,
and final results. The project demonstrated the
ability of an electrochemical cover to inhibit
oxidation of sulfide minerals in mine waste
tailings to control the generation of acid mine
drainage (AMD).
1.1 Project Description
The objective of MWTP Activity III, Project 40
was to demonstrate the effectiveness of an
electrochemical enhancement of conventional soil
covers. The technology, trademarked as AmdEI™
by the technology provider (ENPAR
Technologies, Inc. of Guelph, Ontario, Canada), is
an alternative to conventional earthen covers for
decommissioning and long-term management of
deposits of mill tailings and mine waste rock
containing acid-generating sulfide minerals.
The AmdEI™ electrochemical cover is designed
to prevent the influx of oxygen into the sulfide-
containing tailings or other waste materials to
inhibit AMD generation. The effectiveness of the
technology was assessed by monitoring changes in
sulfide oxidation as manifested by pH and the
concentration of sulfate in the leachate occurring
between electrochemically enhanced cells and
identical test cells with no electrochemical
enhancement by monitoring for 2-years. Due to a
shortened test duration and small test cells,
information regarding longevity of the
electrochemical cover and an economic analysis
for a field-scale system was not performed.
1.2 Purpose
The purpose of this demonstration was to evaluate
the effectiveness of ENPAR's AmdEI™
technology as an enhancement of conventional dry
covers to prevent oxidation of sulfide minerals in
sulfide-containing mine wastes.
Effectiveness of the electrochemical treatment was
defined by the difference between the
electrochemically enhanced cells and the cells
without enhancement with respect to the amount
of sulfide oxidation as:
- reduced amount of sulfate in leachate from
the electrochemically enhanced cells
(treatment cells) compared to untreated
cells (control cells);
- neutral leachate pH from the treatment
cells verses acidic pH leachate from the
control cells;
- reduced conductivity in leachate from the
treatment cells compared to control cells;
and
- retention of total sulfur in the upper
tailings in the treatment cells compared to
reduced sulfur (and pyritic sulfur) in the
upper tailings portion of the control cells.
1.3 Project Schedule
Original plans were to conduct the demonstration
at Tailings Impoundment # 1 at Barrick Gold's
Golden Sunlight Mine (GSM) (formerly Placer
Dome, Inc.) located near Whitehall, Montana. In
April 2003, the EPA Project Officer suspended the
project due to concerns regarding the suitability of
the intended test site. In May 2003, MSE was
directed to scale the project down and perform it
under more controlled conditions. In the same
timeframe, GSM management chose not to host
the project at their site. It was therefore decided to
transport materials from GSM to MSE and
conduct the demonstration at MSB's site in Butte,
Montana.
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In September 2003, test materials, including
tailings and soil cover, were transported from
GSM to the MSB facility. Set-up of the cells
began in September 2003 and installation was
completed in October 2003. Beginning in May
2004, water was applied regularly and leachate
pumped weekly throughout the summer and fall.
Operations were suspended in October 2004 due
to freezing temperatures. Water application
restarted in May of 2005 and continued until
October 2005 when the project was terminated and
the test cells dismantled.
1.4 Report Structure
The final report has been organized systematically
to facilitate ease of review. Starting with the pre-
demonstration activities of the project, the
document continues through the demonstration
site description, the technology description,
experimental test design, data collection, analysis,
and evaluation. Other pertinent information
concerning laboratory performance, field
sampling, and analysis are provided as supporting
documentation in Appendices A and B.
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2. Demonstration Participants and Responsibilities
2.1 Demonstration Participants
The organization and execution of the
Electrochemical Tailings Cover project was a
collaborative effort between the technology
developer and support organizations listed in
Table 2-1.
2.2 Responsibilities
Demonstration of the technology was set up by the
developers with support and operation from MSB,
under the guidelines of the quality assurance plan
(QAPP). Specific responsibilities are outlined in
the following paragraphs.
2.2.1 MSE Technology Applications
MSE worked in consultation with the technical
lead, EPA, and was responsible for:
- developing the work plan and QAPP;
- selecting an appropriate demonstration
site;
- acquiring and transporting tailings from
GSM for the demonstration;
- providing backhoe, bobcat, other earth
moving equipment, and personnel needed
for construction of the demonstration
installation;
- irrigation water for demonstration
installation;
- pumping and disposal of leachate from
test cells;
- documenting the experimental
methodology and operation of the
technology;
- training operational and sampling
personnel;
- performing field analysis and sampling
activities, including duplication,
- packaging, labeling, storing, and shipping
of samples;
- selecting and verifying a qualified
analytical laboratory for demonstration
quality assurance (QA) sample analysis;
- managing, evaluating, interpreting and
reporting of demonstration data;
- evaluating and reporting technology
performance; and
- developing the final report for the
technology demonstration.
2.2.2 Developers
ENPAR is the sole developer of the
electrochemical tailings cover technology used in
this demonstration. ENPAR was responsible for:
- supporting the QAPP preparation;
- design and field installation as well as test
cell configuration including specifications
for instrumentation and monitoring
systems;
- overseeing the selection of tailings and
cover material from GSM to be used in the
demonstration;
- characterization of tailings and soil cover
materials used in the field installation;
- supervising the installation of the
experimental cells at the MSE facility
including installation of culverts, filling of
cells with tailings, covering cells, anode
installation, and testing electrical
connections;
- monitoring the installation; and
- training MSE personnel in proper
sampling and measurements as required.
Table 2-1. Demonstration Support and Developer Organizations
Organization
U.S. Environmental Protection Agency
U.S. Department of Energy
MSE Technology Applications, Inc.
ENPAR Technologies, Inc.
Principal Contact
Diana Bless
Gene Ashby
Brian Park
Gene Shelp
Telephone Number
(513)569-7674
(406) 494-7298
(406)494-7415
(519)836-6155
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3. Predemonstration Activities
3.1 Site Selection
Original plans were to conduct the demonstration
at Tailings Impoundment #1 at GSM. ENPAR
conducted initial characterization of the soil cover
material and tailings from Tailings Impoundment
# 1 in the fall and winter of 2002 to obtain
information for design of the field installation. In
April 2003, the EPA Project Officer suspended the
project due to concerns regarding the suitability of
the intended test site. Of particular concern was
the dryness of the tailings, with little chance for
the collection of leachate samples. In addition, the
tailings were partially oxidized, making it difficult
to quantify the extent of oxidation over the course
of the project. In May 2003, MSE was directed to
scale the project down and perform it under more
controlled conditions.
As previously mentioned, during this same
timeframe, GSM lost interest in conducting the
project at their site. It was therefore decided to
transport test materials, including tailings and soil
cover, from GSM to MSE and perform the
technology demonstration at MSE. Tailings
Impoundment #1, the original test site, had been
previously capped and permitted. Therefore,
collection of tailings would have been disruptive.
Consequently, tailings were obtained from
Tailings Impoundment #2. These tailings were
similar to those from Impoundment # 1 with the
exception of a slightly coarser texture. Prior to
placement of the tailings on Impoundment #2, the
material was passed through a hydrocyclone
allowing only the coarse fraction to be deposited
on the impoundment. This was advantageous, as
the coarser material facilitated water flow
distribution through the test cells.
3.2 Regulatory Plans and Classifications
An access agreement between GSM and MSE was
finalized in August 2003. The purpose of the
agreement was to allow MSE to obtain tailings and
soil cover for the demonstration and then return
the soil and tailings after the demonstration was
complete. The agreement was modified in
September 2004, due to the extension of the
project for an additional year.
3.2.1 Hazards Classification
Excavation work necessary for setup and
dismantling of the installation involved several
risks. Potential risks were:
- electrical lines;
- other utilities such as gas pipelines; and
- hazards associated with the use and
operations of heavy equipment, such as
tipping of the equipment and injuries that
can result from being stricken or crushed
by heavy equipment.
Installation setup and dismantling activities were
monitored by health and safety personnel.
Leachate accumulated during the demonstration
was analyzed for chemical hazards before
disposal.
3.2.2 Quality Assurance Project Plan
A QAPP was developed for this project and
submitted to the EPA Office of Research and
Development for review and approval (Ref 1).
The QAPP served as the standard operating
procedure (SOP) for sampling, sample
preparation, analytical laboratory protocol, and
data reduction.
3.2.3 Analytical Laboratory
The selection of the analytical laboratory to
process the demonstration samples was based on
appropriate analytical capabilities, qualifications,
and overall cost. The HKM Laboratory (now the
MSE Laboratory) in Butte, Montana, was selected
since it has extensive experience providing the
type of analysis needed for evaluation in this
project. An added benefit was the proximity of the
laboratory to the MSE facility, where the
demonstration was conducted. Samples were
transported to the laboratory within one day of
collection, prior to the expiration of any holding
times for the requested analysis.
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4. Demonstration Installation Description and Design
The test cells for the AmdEI™ technology
demonstration were setup at the MSB Testing
Facility in September 2003. Four in-ground test
cells (two electrochemically enhanced treatment
cells, Tl and T2, and two untreated cells, Cl and
C2) were arranged in a square for ease of
construction and to facilitate irrigation
(Figure 4-1). Each test cell consisted of a 5-foot-
diameter in-ground hole 10 feet deep. The test
cells were contained within an upright corrugated
steel culvert lined with an acid-resistant, water-
impervious liner to contain the leachate. The top
of each cell liner was located approximately
6 inches below the final grade. The total volume
of each test cell was 7.3 cubic yards. A cross
section view is shown in Figure 4-2.
The bottoms of the test cells were lined with
1.5 feet of quartz sand to facilitate collection of
leachate. The use of high-grade quartz sand
minimized the possibility of chemical reactions
between the leachate and sand that could confound
the results. Approximately 7.5 feet of tailings
were placed in each cell on top of the quartz sand,
with approximately 1.5 feet of soil cover obtained
from GSM placed on top of the tailings. The
1.5-foot soil thickness was selected as a
compromise to a more typical 3-foot thickness, as
an effort to promote oxidation in the control cells
during the relatively short 2-year test period. The
soil cover was not compacted. The test cells that
used electrochemical enhancement had the
cathode mesh placed on top of the tailings and
below the soil cover, and were wired to sacrificial
anodes placed within the soil cover. The cathode
mesh is shown on top of treatment cell Tl in
Figure 4-3. This cathode mesh was harnessed to
the magnesium anode shown in Figure 4-4.
Each test cell was equipped with a central 2-inch
diameter well for the collection of leachate and to
control the depth of an artificial water table. The
well was curved at the bottom to form a water trap
and prevent the influx of oxygen into the bottom
of the tailings through the well. "Beads" of
bentonite grout were placed at identical locations
in all cells (i.e., around the outer edge of the test
cell, at the top of the cell and at the soil/tailings
interface, as well as the same locations around the
well) to prevent oxygen transport along those
paths. Figure 4-5 shows the bentonite beads
around the outer edge of the test cell and the
2-inch well pipe.
An irrigation system was installed to apply water
to the test cells during the warmer months. The
additional water was intended to further challenge
the electrochemical cover and accelerate oxidation
in the test cells during the relatively brief 2-year
test. Meteorological data for the Butte area
indicated an average annual precipitation of
12.3 inches, primarily received as rainfall in the
summer months. The irrigation system
supplemented the total annual precipitation,
yielding a total annual precipitation to the test cells
of approximately 30 inches. The increased
amount of precipitation to the test cells was
expected to ensure adequate volume for leachate
sample collection and promote sulfide oxidation in
the tailings.
After placement of the culvert sections in the
ground, silica sand was placed in each cell to
provide a small cone shape in the floor so that
leachate was directed toward the center of the cell.
Pre-fabricated 60-mil high-density polyethylene
(HDPE) liners were placed in each cell. The
central well was located in each cell and 1.5 feet
of silica sand was placed in the bottom of each
cell. Tailings were then loaded into the cells. The
cells were loaded using a small "Bobcat" front-end
loader, placing one bucket-load in each cell in a
clockwise fashion [i.e., bucket-loads were placed
sequentially in cells Tl (Treatment #1), T2
(Treatment #2), C2 (Control #2), and Cl (Control
#1), referring to Figure 4-1]. After the addition of
tailings, approximately one vertical foot each, the
tailings were distributed by hand within each cell
to ensure there were no gaps or air pockets. There
was a slight deviation in the loading for test cell
Cl, which was filled to about 1.5 meters from the
top of the culvert before the previously described
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sequence was followed. Samples were taken at
approximately 1-foot intervals and submitted to
the laboratory for acid-base accounting (ABA)
analysis. Simultaneous loading of the test cells
ensured reasonable homogeneity and an equal
starting point for all treatments. In addition, the
tailings used for testing were obtained from a
single location on the Impoundment #2 dam; these
tailings had been greatly homogenized by passing
through GSM's mill (i.e., crushing, grinding, vat
leaching) and then deposited at approximately the
same time. 1.5 feet of soil cover from GSM was
placed in each cell, with the final grade being 6
inches above the top of each cell resulting in cells
that were representative of being in the ground.
The cells' ground cover was extended above grade
to prevent the possibility of snowdrifts
accumulating in an uncontrolled manner and
channeling water and/or oxygen down the sides of
the cells. The final test cell configuration is shown
in Figure 4-6.
A central irrigation system was installed, with one
sprinkler head in the center of the cell arrangement
that delivered water to all four cells. The
irrigation system was calibrated so that the amount
of water was known and uniform.
Upon completion of test cell installation in
October 2003, irrigation water was applied
regularly (and leachate pumped out weekly) until
cold weather prohibited further irrigation. The
purpose of this was to initiate water flow through
the system and to allow the bacteria responsible
for facilitating sulfide oxidation (e.g., Thiobacillus
ferrooxidans) to become acclimated to their new
environment; this could be thought of as
"priming" the system. Little activity was expected
during the winter months due to low temperatures
and no additional supplemental water. Beginning
in the following spring, May 2004, water was
regularly applied and leachate pumped out weekly
throughout the summer and fall, until operations
were suspended due to freezing temperatures in
October 2004. Water application began again the
following spring in May and continued until
October 2005, when the project was terminated
and the cells dismantled.
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Treatme/t 1 (T1)
Co
Junction Box
Treatment 2 (T2J
Anodes
Sample Well
60 mil PVC Liner
Bentonite
Culvert
Irrigation System (Sprinkler Head)
Sample Well
Plot Area (15' Radius
for Irrigation System)
Bentonite
Culvert
60 mil PVC Liner
Figure 4-1. Top view of demonstration installation.
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Anode Lead Wires
Cathode Lead Wires
Sample Well (2" PVC Pipe)
Bentonite
Final Grade (Ground Surface)
Anode (Treatment Cells Only)
60 mil PVC Liner
Cover Material
Cathode (Treatment Cells Only)
Corrugated Steel Culvert
Non-oxidized (Fresh) Tailings
Leachate Sample Chamber
Sand
Excavation Grade
Figure 4-2. Cross-sectional view of cell installation.
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r /•••
Figure 4-3. Cathode mesh in treatment cell Tl.
Figure 4-4. Magnesium anodes.
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Figure 4-5. Bentonite beads around test cell outer edge and well pipe.
Figure 4-6. Test cell final configuration September 30, 2003.
10
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5. Demonstration Technology Description
This demonstration implemented ENPAR's
electrochemical cover technology. One of the
conventional approaches currently used to control
the generation of AMD from mining waste is to
install engineered dry earthen or soil covers over
the waste material. In these types of installations,
earthen materials trucked from local sources are
commonly used to construct dry soil covers. The
AmdEI™ technology is designed to reduce the
amount of earthen material/soil cover needed for a
typical repository. The cost of earthen covers is
dependent upon the thickness and complexity of
the cover and the distance the earthen materials
must be transported to the site.
The ENPAR technology is designed to limit the
infiltration of water and oxygen into sulfide-
containing mill tailings and mine waste rock; thus,
eliminating oxidation of the sulfide minerals, and
consequently inhibiting the generation of AMD.
This electrochemical cover technology is an
enhancement of conventional dry covers and
consists of a cathode (i.e., steel mesh), an
electrolyte (i.e., the soil cover mixture), and an
anode (i.e., a sacrificial material such as
magnesium). The concept of the electrochemical
cover is to prevent oxidation of sulfide minerals by
inhibiting the infiltration/diffusion of oxygen into
the sulfide wastes. The fundamental
electrochemical process is the transfer of electrons
from the anode to the cathode through an external
circuit due to the presence of the galvanic couple
set up between the cathode and anode. This
transfer of electrons produces a chemical reaction
at the cathode/electrolyte interface that reduces the
concentration of oxygen and produces alkalinity
according to the following reaction:
2H2O + O2 + 4e -> 4OH
The technology is covered by U.S. patent
5,630,934 (May 20, 1997). There are both
Canadian (209581) and international (9927716.2)
patents pending.
There is also some evidence that the cathode can
generate an electro osmotic effect by attracting
dissolved cations, creating a localized zone with a
higher concentration of cations compared to the
surrounding soil matrix. The result is a difference
in osmotic potential between the cathode surface
and the soil matrix producing a localized gradient
where water is drawn to the cathode, increasing
the moisture content around the cathode. This
effect would also inhibit the transport of oxygen to
the underlying sulfide waste material, further
enhancing the ability of the electrochemical cover
to prevent AMD.
The AmdEI™ electrochemical cover is
independent of the mineralogy and the associated
electrical properties of the underlying waste
material. The system provides a uniform sink for
oxygen established over the entire surface of the
tailings/waste rock deposit. Given the nature of
the electrochemical system, the cathodic material
is prevented from breakdown, similar to cathodic
protection of underground steel pipes and tanks.
11
-------
6. Experimental Design
6.1 Technology Demonstration Objectives
The objective of the project was to demonstrate
the effectiveness of electrochemical enhancement
of conventional soil covers to inhibit the oxidation
of sulfide minerals in sulfide-containing mine
waste, and consequently control AMD generation.
6.2 Factors Considered
Several factors considered in the development of
the experimental design were:
- type of material to be used for tailings and
cover;
- selection of the materials to be tested;
- selection of analytical parameters to
measure extent of oxidation;
- design of the test cell;
- amount of precipitation needed to
maintain the appropriate artificial "water
table" and promote weathering; and
- sampling frequency of the test cell
leachate.
6.3 Installation Tailings Characterization
Initial samples of tailings taken during cell loading
were analyzed for ABA, total metals, size
distribution, and paste pH. The laboratory data is
presented in Appendix A.
6.3.1 Acid-Base Accounting
The ABA results were used to establish the acid-
generating variability between cells as well as
within cells. The ABA values provided the initial
sulfur concentrations for the test. Some samples
were obtained from the quartz sand and soil cover
for ABA for completeness, even though these
materials were known to be free of acid-generating
sulfur. This is verified by the ABA results as
shown in Appendix A.
6.4 Sampling Design
Quality control (QC) sampling format was derived
from the QAPP. The sampling frequencies were
somewhat relaxed when the decision was made to
extend the demonstration an additional year to
October 2005. Sampling was performed in three
separate phases: 1) field installation, 2)
monitoring, and 3) post-test or completion. The
type of samples, parameters, classification (i.e.,
primary/non-primary), matrix, and proposed
frequency were defined in the QAPP. The original
sampling criteria is found in Appendix B.
6.5 Monitoring Phase Measurements
Measurements obtained after the installation and
prior to dismantling of the test cells were
considered monitoring phase samples. Samples
from this phase comprise the majority of data
obtained during the demonstration. This data
reflected the impact that the electrochemical cover
technology had on the treatment cells during the
demonstration.
6. 5. 1 Electrochemical Measurements
The electrochemically enhanced treatment cells
had the cathode mesh placed on top of the tailings
and below the soil cover, and were wired to
sacrificial anodes placed within the soil cover.
During the monitoring phase, voltage and current
measurements were made intermittently, but at
least monthly, to ensure the galvanic couple was
present. The galvanic couple provides the
fundamental electromotive force (EMF) that
maintains the desired reducing conditions in the
treatment cell tailings.
6.5.2 Sulf ate and pH Measurements
Leachate sulfate and pH measurements were taken
to assess oxidation of the tailings during the
monitoring phase. Sulfate and acidity are
produced during the oxidation of tailings
containing sulfide minerals. Typically, pyrite is
the sulfide mineral present that provides the sulfur
source in AMD generation. Pyrite undergoes
oxidation to generate AMD by the following
equation:
7O2 + 2H2O + 2FeS2
4SO4
2Fe2
12
-------
Fresh tailings contain little sulfate; however, as
water percolates through the tailings as they are
being oxidized, the sulfate will increase while the
pH decreases. By this mechanism of measuring
the leachate sulfate and pH over time, the progress
of sulfide oxidation can be monitored. In the
demonstration, leachate sulfate concentration was
used as the primary parameter to indicate the
presence of oxygen in the tailings; thus, showing
the amount of sulfide oxidation that has occurred.
Data was compared between treatment and test
cells to indicate the effectiveness the
electrochemical cover had on oxidation of the
sulfide minerals and AMD.
During the period when water was applied,
intermittent leachate samples were collected and
analyzed for sulfate and pH as primary
measurements. Total leachate volume was
recorded and used to calculate total mass of sulfur
removed. Specific conductance (SC)
measurements were taken in the field from the
combined leachate. As AMD is generated,
increases in total dissolved solids should be seen,
resulting in increasing SC values.
6.5.3 Dissolved Metals
Leachate samples analyzed for dissolved metals
were gathered periodically throughout the project.
As a secondary measurement, dissolved metals
results provided additional information to assist in
the interpretation of the chemistry in the test cells.
6.6 Completion Phase Measurements
At the completion of the project, in the fall of
2005, the test installation was dismantled and the
tailings and soil cover were returned to GSM.
Prior to dismantlement, three tailings cores were
taken by the geoprobe in random locations in each
test cell for visual evaluation of oxidation and
laboratory analysis. Samples were taken from the
top three inches of the cores and analyzed for
ABAandl:lpH.
6.6.1 Acid-Base Accounting
The ABA samples taken at the completion of the
demonstration were to determine changes in the
sulfur content of the upper-most portion of the
cells. Comparison of the tailings total sulfur and
pyritic sulfur content was used to evaluate
oxidation in the test cells, as well as determine the
effectiveness of the electrochemical cover when
compared with the treatment and control cells.
6.6.2 1:1 pH
Since each core sample was limited, 1:1 pH
analysis was used at test completion instead of the
saturated paste pH. The 1:1 pH is a measure of the
hydrogen ion activity in a soil slurry. This
measurement indicates the presence or absence of
free acids in the soil, much like a saturated paste
pH. Differences between the two methods are
equilibration time and the solid to liquid ratio.
Equilibration time for the paste pH is at least four
hours, but typically overnight, while a 1:1 pH is
approximately half an hour. This means that there
is less time for slightly soluble salts to dissolve
and moderate the pH in the 1:1 pH determination.
The solid to liquid ratio is greater for the saturated
paste pH than for the 1:1 pH, but the dilution
effect alone does not greatly alter the resultant pH.
The pH result is not significantly biased between
the two methods because de-ionized water is used
in the slurry and paste, and has no buffering
capacity to contribute to the mixture.
6.7 Statistical Analysis
The original experimental design was to be a
completely randomized design using a one-way
treatment structure with repeated measures. Due
to changes in the frequency and number of
samples taken when the project duration was
extended, the application of the original design for
statistical analysis was not possible. In planning
the demonstration, the factors considered critical
to indicate the success of the demonstration were:
- sulfate leachate production;
- leachate pH; and
- total mass of sulfate leach from the test
cells.
The percent reduction in the oxidation of sulfide is
quantified by measuring the difference between
the mass of sulfate leached from the treatment and
control cells as shown by the equation:
13
-------
If the treatment is effective, the percent reduction
of oxidized sulfide would increase with time.
Figure 6-1 presents the results from the
demonstration. Inspection of the plot reveals no
specific trends, and the percent reduction appears
to be nearly random with respect to time. It must
be concluded that either reduction of oxidized
sulfide was an inappropriate measure of the
electrochemical cover effectiveness, or the cover
was ineffective.
% reduction = (SO42
control
-SO
4 treated.
)100
-------
Percent Reduction of Sufide Oxidized
100.00% -I
c
o
u
3
V U.UU/o
a:
c
o
CO
X
0
01
4/23/04
<
\.
\^
4 • N.
V
^
\. ^
^^^ / \
^^^^ / \
, ^^4
V
8/1/04
11/9/04 2/17/05 5/28/05
Date
f
I
^ \
\ /
\ >
\ /
Y^^
\ w
4
9/5/05 12/14/05
Figure 6-1. Percent reduction in sulfide oxidation.
Table 6-1. Pre-Test and Post-Test ABA Total Sulfur Comparison
Total Sulfur Standard
Range
Test Cell Project Phase Average (%) Deviation (%) 2 CT (%) Average + 2 CT (%) Average - 2 CT (%)
Cl
C2
Tl
T2
Initial 5.40
Final 0.05
Initial 6.07
Final 0.04
Initial 9.44
Final 4.51
Initial 4.78
Final 4.44
0.64 1.29 6.69 4.11
0.010 0.02 0.07 0.03
0.66 1.33 7.40 4.74
0.000 0.00 0.04 0.04
1.40 2.80 12.24 6.64
0.18 0.35 4.86 4.16
0.23 0.45 5.24 4.33
0.14 0.27 4.72 4.17
Table 6-2. Pre-Test and Post-Test ABA Pyritic Sulfur Comparison
Pyritic Sulfur Standard
Range
Test Cell Project Phase Average (%) Deviation (%) 2 CT (%) Average + 2 CT (%) Average - 2 CT (%)
Cl
C2
Tl
T2
Initial 4.45
Final 0.03
Initial 4.88
Final 0.02
Initial 7.83
Final 3.98
Initial 3.67
Final 4.01
0.61 1.23 5.68 3.22
0.010 0.02 0.05 0.01
0.65 1.30 6.18 3.58
0.010 0.02 0.04 0.00
1.52 3.05 10.88 4.78
0.30 0.60 4.58 3.38
0.33 0.65 4.32 3.02
0.14 0.28 4.29 3.73
15
-------
7. Field Sampling and Analysis
7.1 Techniques and Methods
All samples were taken and submitted to the
analytical laboratory within the guidelines
provided in the QAPP. All samples delivered to
the laboratory were accompanied by chain-of-
custody (COC) to serve as a record of the
analytical request and transfer of possession.
Installation tailings samples were random grab
samples taken at approximately 1-foot intervals in
1-gallon Ziploc bags as the cells were being
loaded. A composite sample was taken for metals
analysis. A sample of the sand and soil cover
sample from each of the test cells was also
obtained for analysis.
Field data was collected during the monitoring
phase of the project from aqueous samples that
consisted of 1) plant water used for irrigation of
the cells, and 2) cell leachate samples. Field
parameters taken on the fresh aliquots of the
aqueous samples were pH, SC, oxidation-
reduction potential (ORP), and dissolved oxygen.
These measurements were made with the YSI 556
Multi Probe System.
Leachate pumped from the test cells was collected
in a graduated tank or weighed to determine the
volume produced from each of the cells.
Irrigation water was analyzed for the parameters
of dissolved metals, sulfate, alkalinity, and
chlorine. Leachate samples were analyzed for
total metals, pH, and sulfate. Alkalinity and
sulfate samples were taken in 500-mL HDPE
bottles. Total metals were taken in 500-mL HDPE
bottles and dissolved metals in 250-mL HDPE
bottles. Chlorine was taken in a 250-mL HDPE
bottle with minimal headspace. All HDPE sample
bottles were rinsed three times with the subject
water before collecting the aliquot for analysis.
Samples were stored at 4 °C until delivery to the
analytical laboratory.
Core samples were taken using a Geoprobe at the
completion of testing, immediately prior to
dismantling the test cells. Three cores were taken
from each cell in random locations and stored in
sealed 1-inch plastic tubes under refrigeration until
analyzed.
7.2 Field Sample Analysis and Data
Recording
Parameters measured in the field were:
- pH;
- SC;
- ORP;
- dissolved oxygen; and
- leachate volumes.
All calibration and sample measurement data was
recorded in a bound all-weather notebook with
waterproof ink. To ensure that field measurements
were of acceptable quality, all parameters were
required to meet the calibration check criteria
stated in the QAPP (Section 5). The results of the
calibration checks were likewise recorded in the
project logbook for reference.
7.3 Instrument Accuracy
The accuracy of the field measurements is directly
related to the accuracy of the instrumentation and
procedures used in obtaining the values. The YSI
556 Multi Probe System was calibrated in
compliance with the requirements set forth in the
QAPP. The requirements are outlined in
Table 7-1.
16
-------
Table 7-1. Calibration Requirements for Process Field Measurements
Parameter
Measurement
Classification
Process
Instrument
Calibration
Procedure
Frequency of
Calibration
Expected Range/
Expected Accuracy
SC
Dissolved
Oxygen
ORP
Leachate
Volumes
Primary
Nonprimary
Nonprimary
Nonprimary
Primary
pH Electrode
Conductivity
Electrode
Dissolved
Oxygen
Electrode
Redox
Electrode
5-gallon tank
2 points
Calibrate with 1412
microSiemens per
centimeter (uS/cm)
standard
Per Manufacturer's
Specification
ZobelPs Solution
Manufacturer's
Graduation
Daily -2.00 to 16.00
+0.1
Daily 5,000 to 20,000
|iS/cm
+1%
Daily 0 to 10 milligrams
per liter (mg/L)
42%
Daily -250 to +250
millivolts (mV)
+20 mV
NA 3 to 10 gallons, 0.1
gallon
17
-------
8. Discussion
The ENPAR project was originally setup to be
conducted at the GSM. Concerns with the amount
of precipitation, suitability of demonstration
location and loss of interest on the behalf of GSM,
the demonstration was moved to the MSB facility.
The analytical results of samples taken are
presented within the following sections. Data is
presented in graphs and a summary of the quality
assurance activities from the project specific
QAPP are contained in Appendix C.
8.1 Field Installation
The experimental setup consisted of two treatment
cells and two control cells (Figure 4-1). The
natural precipitation was augmented by a sprinkler
system that was intended to provide enough
moisture to maintain an artificial water table in the
cells and provide ample water to generate leachate
sampling, and accelerate the weathering processes
in the tailings (Figure 4-2).
8.1.1 Acid-Base Accounting
The demonstration cells were sampled during
installation while they were being filled with
tailings at approximately 1-foot intervals.
Samples of the sand, used in the saturated zone of
the cells, and soil cover were obtained during the
installation process. The ABA results for these
samples are tabulated in Appendix A. The field
installation samples were analyzed for size
distribution, saturated paste pH, and total metals.
Tabulation of these results is found in
Appendix A.
8.1.1.1 Data Interpretation
The average sulfur content of the tailings in the
test cells ranged from 4.78% to 9.44% sulfur, with
the overall average being 6.42%. Cell Tl, which
had the highest total sulfur concentration,
exhibited the largest variability amongst the
analysis of the 1-foot interval samples, and it was
notable that results from this cell displayed the
largest variation in the referee sample results. The
majority of the sulfur content in the tailings
samples was initially present as pyritic sulfur. The
sand and soil cover had very little, if any, sulfur
present, which is shown by the results being below
or at the method detection limits.
8.1.2 Other Installation Analysis
Saturated paste pH, total metals, and sieve analysis
were performed on the composite samples taken
during the demonstration installation. The results
are tabulated in Appendix A. The analysis shows
the particle size to be relatively consistent between
the test cells. The mean particle size is 0.22 to
0.23 millimeters in diameter (Appendix A) and the
saturated paste pH is nearly neutral for each test
cell. Metals are similar between the test cells. All
metals show little variation in concentration
between the composite samples, as depicted by a
relative standard deviation of less than 15%.
8.2 Monitoring Period Leachate Analyses
The majority of the data was taken during the
monitoring phase of the demonstration. The
purpose of the data obtained during this phase was
to detect changes in the physical or chemical
parameters of the leachate. These data could
provide insight into the progress of oxidation
within the treatment and control cells. A
requirement during this phase was to establish an
artificial water table within the test cells so there
would be an aqueous reservoir from which to
obtain aqueous samples. Leachate samples were
pumped from the artificial water table within the
test cells. The water depth in each test cell is
presented in Figure 8-1.
8.2.1 Voltage and Current Measurements
The voltage and current were monitored
throughout the demonstration to insure the
galvanic couple, between the cathodic covering
and the anode in the treatment cells, was
established at installation and maintained until
dismantling. The galvanic couple is a required
element to provide electrons for the chemical
reactions necessary in the operation of the
electrochemical technology. The treatment cells
voltage and current data is presented in Figures
18
-------
8-2 and 8-3. The graphs show that indeed an
electrical connection, galvanic couple, was present
throughout the project.
8.2.2 Leachate Analysis
The leachate from each test cell was analyzed for
pH, sulfate, SC, and total metals during the
monitoring phase. The leachate volume produced
was also recorded.
8.2.2.1 Leachate Volume
The leachate volume accumulated over the
duration of the demonstration is shown in Figure
8-4. The data indicates that more leachate was
pumped out of the control cells compared to the
treatment cells. Reasons for the disparity in the
leachate production remain unclear, since the soil
physical properties appear to be relatively similar
between all the test cells from the installation data.
One potential cause is that the electrochemical
cover may have impeded migration of the
irrigation water and precipitation; possibly
retaining water in the upper portions of each cell,
therefore allowing more evaporation in the
treatment cells.
8.2.2.2 Test Cell pH
The pH of the test cell leachates at sampling, are
shown in Figure 8-5. No significant difference
between the control and treatment cells was noted
for the duration of the demonstration. In all the
test cells, the pH remained constant, with the
exception of the samples taken on October 6,
2004. The pH readings from October 6, 2004 are
questionable, since tank collection water had
siphoned back into the wells. The test cells' pH
was relatively neutral, with the pH still above 6.3
at the conclusion of the demonstration.
8.2.2.3 Sulfate
Sulfate was a primary parameter for determining
the effectiveness of the electrochemical cover
sulfide oxidation. The leachate sulfate
concentration overtime is shown in Figure 8-6.
The cumulative mass amount of sulfate leached
from the test cells is displayed in Figure 8-7.
Sulfate production is one measure of oxidation of
sulfides in the tailings. If the cover technology is
effective, it can be projected that the treatment
cells would yield less sulfate over time than the
control cells. From observation of Figures 8-6 and
8-7, for leachate sulfate and cumulative sulfate, no
significant differences between the treatment and
control cells are readily apparent. Generally,
leachate sulfate concentration in all the cells was
initially high and then dropped quickly to a
relatively steady value, or slightly decreasing
level. The initial peak in leached sulfate from the
test cells, which is common between all the cells,
indicates that the initial sulfate content within the
cells has been flushed from the tailings. The
apparent stabilization of the leached sulfate, near
the conclusion of the demonstration, may reflect
the true rate of sulfate production. The rate (i.e.,
kinetics) of sulfide mineral oxidation may be too
slow to cause significantly measurable differences
between the treatment and control cells in leached
sulfate during the timeframe of this demonstration.
It cannot be concluded whether sulfate is retained
preferentially in the treatment cell verses the
control cell from the sulfate data obtained in this
demonstration.
8.2.2.4 Specific Conductance
Specific conductance results are shown in Figure
8-8. Consistent with expectations, the test cell
leachate SC started out relatively high and
decreased gradually during the demonstration.
Initially, the soluble salts were washed from the
tailings, followed by the slightly soluble salts,
which was reflected by the decrease in leachate
SC. A significant secondary rise in conductance
was not observed. It was projected that oxidation
of sulfide in the tailings in the control cells would
generate more soluble salts; hence, a rise in the
SC. Throughout the demonstration, the treatment
cells' conductance remained higher than the
control cells. This may be partially explained by
dilution effects. If similar amounts of dissolved
salts were leached from all the test cells, cells with
greater leachate production (i.e., control cells)
would have a lower SC when compared to the
treatment cells, producing less leachate.
19
-------
8.2.2.5 Total Metals
Total metals summary is shown in Table 8-1.
There does not appear to be any significant
differences in metals concentration trends between
the control and treatment cells. Distinct
observations that can be made about all of the test
cells involve calcium, iron, and sodium.
Throughout the demonstration, the calcium
concentration was constant, the iron concentration
increased, and the sodium concentration decreased
within each test cell. The mechanisms behind the
concentration changes are likely independent of
each other. Leaching of soluble salts over time
will cause the decrease in sodium. The increase in
the iron leachate concentration may be due to
oxidation of the sulfides in the tailings. The data
from the October 6, 2004 samples was biased
because tank water was siphoned back into the
wells. This event correlated with an anomalously
high pH in the leachate, which impacted the
leachate by causing the iron to be precipitated.
Calcium was remarkably constant suggesting that
the calcium solubility in the leachate may be
controlled by a stable mineral phase.
8.2.3 Irrigation Water
Several parameters were monitored in the
irrigation water that was used to augment the
meteoric water during the demonstration. The
field and laboratory results are available in
Appendix A. The irrigation water physical and
chemical parameters were relatively consistent.
8.3 Post-Demonstration Measurements
Post-demonstration data was acquired from three
separate cores taken at random locations from
each test cell. There were no differences in
coloration between control and treatment cell
samples to provide any visual indication of
oxidation in the cells. If oxygen penetration into
the test cells is limited, any chemical changes
resulting from oxidation would occur near the
surface of the cell, and the effects should be
detectable in the upper portion of the core.
Samples from the top of the core would have
highest probability for showing the effects of
oxidation; therefore, only the top 3 inches of each
of the 1-inch cores was submitted for analysis to
the MSB Laboratory (formerly HKM Laboratory).
A larger sample would normalize the analysis if
oxidation were limited to the surface of the test
cell.
8.3.1 Acid-Base Accounting
ABA analysis of the core samples determined the
amount and form of the sulfur remaining in the
test tailings at the completion of the
demonstration. There were significant differences
between the treatment and control cell post-test
ABA results. The post-test ABA laboratory
analytical data is presented in Table 8-2. The
results between cores taken from the same test
cells show good precision, as well as good
agreement between treatments. Total sulfur in the
treatment cells was approximately 4.5%, with
about 88% being unoxided pyritic sulfur. In
contrast, the total sulfur remaining in the control
cells was only 0.04% to 0.05%. This is possibly
an indication that the electrochemical cover used
in the treatment cells was effective in inhibiting
oxidation when compared to the control cells.
8.3.2 1:1 pH
Due to the limited sample size submitted, 1:1 pH
was determined in lieu of a saturated paste pH.
The 1:1 pH results are also shown in Table 8-2.
The control cell tailings react significantly
different from the treatment cell tailings when
mixed with deionized water. The 1:1 pH of the
control cells was around 8, while the 1:1 pH of the
treatment cells was approximately 5.6. The lower
relative 1:1 pH from treatment cells may have
been caused by the oxidation/hydrolysis of the
remaining pyritic sulfur or the development of
acidic, secondary phases in the treatment cells
during the sample preparation process.
20
-------
Water Depth vs. Time
o
o
o
CM
§ g
oo
o
o
o
o
CM
s § §
oo
o
o
o
Time
Figure 8-1. Water depth in the test cells over time.
T1 Voltage/Current Measurements
400
200
0
—, -200
g -400
"oT -600
°> -800
3 -1000
> -1200
-1400
-1600
-1800
-T1 Voltage
T1 Instant Off Voltage
-T1 Current
sssssssssssssssssssssssss
Time
Figure 8-2. Treatment cell Tl voltage and current measurements.
21
-------
T2 Voltage/Current Measurements
400
200
0
—, -200 -
C -400
-600
-800
-1000
-1200
-1400
-1600
-1800
-T2 Voltage
T2 Instant Off Voltage
-T2 Current
8888888888888888888888888
CNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCNCN
Time
Figure 8-3. Treatment cell T2 voltage and current measurements.
Cumulative Test Cell Leachate
— 1000-
01
!8
HI
;B ;B s s a a
» " si is a
Date
Figure 8-4. Test cell leachate production.
22
-------
Test Cell Leachate pH
8.00
6.00
Illlllllllllllll
Time
Figure 8-5. Test cell leachate pH,
Test Cells Sulfate vs. Time
16000
14000
12000
"3)10000
"JJ" 8000
"re
2= 6000
(/)
4000
2000
Note,theT2datapoint isisnot validas
it does not c or r el ate by SC or by sulfur
fromlCP. UsingsulfurfromlCPwould
give11,370mg/l.
Illlllllllllllll
Time
Figure 8-6. Test cell leachate sulfate.
23
-------
10000
9000
8000
7000
-------
Table 8-1. Total Metals in Test Cell Leachate
Test
Cell
ID
Cl
Cl
Cl
Cl
Cl
Cl
C2
C2
C2
C2
C2
C2
Tl
Tl
Tl
Tl
Tl
Tl
T2
T2
T2
T2
T2
T2
FIELD ID
ENPAR-C 1-06 1504
ENPAR-C1-071504
ENPAR-C1-100604
ENPAR-C 1-06 1605
ENPAR-C1-083105
ENPAR-C1-101405
ENPAR-C2-061504
ENPAR-C2-071504
ENPAR-C2- 100604
ENPAR-C2-061605
ENPAR-C2-083105
ENPAR-C2-1 01405
ENPAR-T1-061504
ENPAR-T1-071504
ENPAR-T1 -100604
ENPAR-T1-061605
ENPAR-T1-083105
ENPAR-T1-101405
ENPAR-T2-061504
ENPAR-T2-071504
ENPAR-T2-100604
ENPAR-T2-061605
ENPAR-T2-083105
ENPAR-T2-101405
Date
Sampled
6/15/2004
7/15/2004
10/6/2004
6/16/2005
8/31/2005
10/14/2005
6/15/2004
7/15/2004
10/6/2004
6/16/2005
8/31/2005
10/14/2005
6/15/2004
7/15/2004
10/6/2004
6/16/2005
8/31/2005
10/14/2005
6/15/2004
7/15/2004
10/6/2004
6/16/2005
8/31/2005
10/14/2005
Ca
(mg/L)
419
386
372
403
436
464
390
348
344
373
415
416
385
348
316
349
396
394
366
327
298
336
384
386
Fe
(mg/L)
6.66
8.79
0.44
15.8
22.7
18.4
3.18
3.03
0.19
7.40
9.73
12.4
3.68
4.22
1.71
6.85
12.1
13.7
2.45
2.56
0.53
6.71
8.81
11.2
Mg
(mg/L)
436
420
502
381
613
782
1,030
884
850
739
843
886
918
863
907
813
933
871
1,410
1,400
1,260
1,210
1,370
1,430
Mn
(mg/L)
7.09
7.36
5.26
6.61
10.8
14.2
12.3
11.8
10.0
8.00
12.4
13.3
8.16
7.81
5.31
6.11
11.3
9.81
19.6
18.5
13.6
12.8
17.7
18.1
K
(mg/L)
364
346
397
284
239
211
455
386
379
306
229
280
465
422
426
384
319
322
497
450
446
439
358
364
Si
(mg/L)
6.31
6.52
7.90
6.74
8.29
8.46
6.49
6.38
7.39
6.63
8.16
8.28
6.15
6.12
6.37
6.03
7.64
7.97
6.33
6.22
6.43
6.60
7.63
8.69
Na
(mg/L)
959
895
1,150
554
348
226
1,310
1,040
869
617
356
447
1,670
1,540
1,750
1,070
610
527
1,400
1,540
1,740
1,350
765
644
S
(mg/L)
NA
1,790
2,100
1,410
1,520
1,700
NA
2,630
2,370
1,970
1,830
1,980
NA
2,980
3,130
2,490
2,200
2,040
NA
3,750
3,790
3,320
3,040
3,030
NA - parameter not measured
25
-------
Table 8-2. Post-Test Acid-Base Accounting and 1:1 pH Results
Test
Cell
ID
Client Sample ID
Pyritic Sulfur - Insoluble Sulfate - Residual Maximum
Total HNO3 Sulfide-HCl Water Sulfur-Non- Neutralization Potential
Sulfur Extractable Extractable Soluble Extractable Potential Acidity
(%) (%) (%) (%) (%) (tCaCCyiOOOt) (t/lOOOt)
Net
Neutralization pH-
Potential 1:1
(t/lOOOt) (SU)
u
ENPAR-C1-1-120506
ENPAR-C1-2-120506
ENPAR-C1-3-120506
Average
Standard Deviation
Rel. Std. Dev.
0.04
0.06
0.05
0.05
0.01
20.0
0.02
0.04
0.03
0.03
0.01
33.3
0.01
0.01 U
0.01 U
0.01
0.01 U
0.01 U
0.01
0.01
0.01 U
0.01
0.01 U
0.01
73.0
100.0
95.0
89.3
14.4
16.1
1.3
2.0
1.4
1.6
72
100
93
88.3
14.6
16.5
7.9
8.0
8.1
8.0
0.1
1.2
U
ENPAR-C2-1-120506
ENPAR-C2-2-120506
ENPAR-C2-3-120506
Average
Standard Deviation
Rel. Std. Dev.
0.04
0.04
0.04
0.04
0.00
0.0
0.01
0.03
0.02
0.02
0.01
50.0
0.02
0.01 U
0.01 U
0.01
0.01 U
0.01 U
0.01
0.01
0.01 U
0.01 U
0.01 U
0.01
120.0
120.0
110.0
116.7
5.8
4.9
1.2
1.1
1.2
1.2
120
120
110
117
5.8
4.9
8.1
8.0
8.2
8.1
0.1
1.2
i-H
H
ENPAR-T1-1-120506
ENPAR-T1-2-120506
ENPAR-T1-3-120506
Average
Standard Deviation
Rel. Std. Dev.
4.69
4.34
4.50
4.51
0.18
3.9
4.32
3.77
3.84
3.98
0.30
7.5
0.06
0.15
0.27
0.16
0.19
0.29
0.25
0.24
0.12
0.14
0.14
0.13
3.8
7.6
1.3
4.2
3.2
74.9
147
136
141
141.3
-140
-130
-140
-137
5.8
-4.2
5.7
5.5
5.6
5.6
0.1
1.8
ff
ENPAR-T2-1-120506
ENPAR-T2-2-120506
ENPAR-T2-3-120506
Average
Standard Deviation
Rel. Std. Dev.
4.35
4.60
4.38
4.44
0.14
3.1
3.99
4.16
3.88
4.01
0.14
3.5
0.01 U
0.07
0.01 U
0.03
0.32
0.29
0.43
0.35
0.06
0.09
0.13
0.09
5.0
8.2
8.8
7.3
2.0
27.9
136
144
137
139.0
-130
-140
-130
-133
5.8
-4.3
5.9
5.5
5.6
5.7
0.2
3.7
-------
9. Conclusions and Recommendations
The MWTP, Activity III, Project 40,
Electrochemical Tailings Cover demonstration,
has provided some evidence that the
electrochemical tailings cover can reduce the
oxidation of sulfide minerals in sulfide-
containing mine waste. The reduction in
oxidation of sulfur in the tailings was best
shown by the post-test ABA analysis. The
electrochemically treated cells retain total sulfur
and pyritic sulfur at higher levels than in the
control cells that had no special treatment. In
fact, treatment cell T2 retained over 90% of its
original sulfur content. Nearly 50% of the sulfur
was retained in the other treatment cell, Tl;
however, there was a large degree of variation in
the initial sulfur data for this treatment cell,
which seemed somewhat suspect due to initial
high total sulfur content when compared to the
three other test cells. Interestingly, both cells
with the electrochemical treatment retained
about 4.5% total sulfur while the untreated cells
contained less than 0.05% sulfur at the
conclusion of the demonstration. It is apparent
that the sulfur was readily oxidized and leached
away from the top few inches of tailings in the
untreated control cells, since initial total sulfur
in the cells ranged from 4.78 to 9.44%.
Disappointingly, the leachate water samples
failed to provide any real conclusive evidence
about the effectiveness of the electrochemical
tailings cover. No significant trends in leachate
sulfate, total sulfate, or pH could be denoted.
The oxidation rate of the sulfur in the tailings
may be responsible for the inconclusive findings
from the leachate sulfate and pH. The duration
of the demonstration may have been of
insufficient length for the oxidation of sulfide to
dominate the leachate chemistry.
Other factors may have influenced the chemistry
of the leachate as it migrated downward through
the tailings on its path to collection in the base
of the test cells. The calcium and sulfate
concentrations remained relatively constant in
the leachate throughout the demonstration. This
indicates that their concentration in the leachate
may have been controlled by a stable mineral
phase in the sediment. It is quite likely that
gypsum, CaSO4 + 2H2O, may be responsible for
the influence on the calcium and sulfate, since
both are present at considerable concentrations
in the leachate. If indeed gypsum was
controlling the solubility of calcium and sulfate,
any sulfate arising from oxidation of sulfide in
the tailings would be attenuated before it reaches
the reservoir of water at the base of the test cells;
thus, obscuring the sulfate data as a useful
indicator of sulfide oxidation.
9.1 Lessons Learned
When planning any testing demonstration,
especially when it entails a large-scale
demonstration, it is highly important to attempt
to understand the entire system and potential
effects on the analytical data to be collected. In
this demonstration, it was expected that leachate
sulfate and pH would provide the data necessary
to evaluate the effectiveness of the
electrochemical tailings cover. However, the
influence of the tailings and stability of mineral
phases may have confounded the results from
these two parameters. Fortunately, several types
of data were collected, and the ABA analysis
provided some data that allowed an alternative
for evaluation of the electrochemical cover
technology.
Quantification of the amount of sulfate being
leached from the cells was difficult in the
experiment. An alternative leachate collection
format may have improved the accuracy of
determining the amount of sulfur, and other
constituents leached from the tailings.
Dedicated collection barrels for each cell would
provide accurate volume determinations and a
reservoir from which to sample for sulfate and
other analytes of concern. Samples from the
collection reservoir would provide a more
accurate determination of the leachate
constituents.
27
-------
10. References
MSB Technology Applications, Inc., Mine
Waste Technology Program, Quality
Assurance Project Plan - Electrochemical
Tailings Cover, Activity III, Project 40,
October 2003.
28
-------
Appendix A
Laboratory and Field Data
-------
Metals in Test Cell Tailings
Results per dry weight basis
SAMPLE
ID
CRDL
IDL
0310200041
0310200042
0310200043
0310200044
FIELD
ID
ICP-AES
ENPAR-C1-TAILSCOMPOSITE-0925
ENPAR-C2-TAILSCOMPOSITE-0925
ENPAR-T1-TAILSCOMPOSITE-0925
ENPAR-T2-TAILSCOMPOSITE-0925
Test Cell
ID
C1
C2
T1
T2
Al
(mg/Kg)
40.0
6.22
820
829
801
804
As
(mg/Kg)
14.4
7.2
29.1
32.4
32.5
33.9
Cd
(mg/Kg)
2.7
1.354
1.3 U
1.3 U
1.3 U
1.3 U
Ca
(mg/Kg)
1,000
1.48
1,880
2,400
2,310
2,150
Cu
(mg/Kg)
5.0
0.28
133
153
167
141
Fe
(mg/Kg)
20.0
1.8
43,000
46,600
46,600
42,700
Pb
(mg/Kg)
23.4
11.7
16.1 B
14.5 B
12.3 B
18.1 B
M(j
(mg/Kg)
1,000
10,84
4,640
5,270
5,000
4,780
Mil
(mg/Kg)
3
0.6
77.9
96.3
91.8
83.4
K
(mg/Kg)
1000
4.22
1,010
1,030
993
969
Si
(mg/Kg)
5.98
2
575
648
637
498
Na
(mg/Kg)
1000
0.8
237 B
263 B
260 B
245 B
Zn
(mg/Kg)
4
1.3
70.7
94.7
94.0
86.4
Inter-Cellular Statistics
Average
Standard Deviation
Relative Standard Deviation (RSD)
814
13.3
1.6%
32.0
2.0
6.4%
1.3 U
N/A
N/A
2,185
228
10.4%
149
14.8
10.0%
44,725
2169
4.8%
15.3 B
2.5
16.1%
4,923
275
5.6%
87.4
8.3
9.5%
1,001
25.9
2.6%
589.5
68.9
11.7%
251
12.3
4.9%
86.5
11.2
12.9%
Legend:
IDL- Instrument Detection Limit
CRDL- Contract Required Detection Limit
U- analyte undetected
B - analyte detected, less than CRDL
-------
Test Cell Tailings Acid-Base Accounting Results
Fraction
Method of
Extraction
Total
Sulfur
(%)
None
Pyritic
Sulfur
(%)
Hot HHO;:
Leach
Soluble
Sulfur
(%)
Hot
Water
Leach
Insoluble
Sulfur
(%)
HCI
Leach
Organic
Sulfur
(%)
Residual
Neutralization
Potential
(HOOt)
Cell-C1
Avg.
Std. Dev.
RSD
5.40
0.64
11.9
4.45
0.61
13.8
0.37
0.12
31.8
0.10
0.07
69.9
0.51
0.16
30.7
14.9
1.9
12.5
Cell-C2
Avg.
Std. Dev.
RSD
6.07
0.66
10.9
4.00
0.65
13.3
0.37
0.12
32.5
0.25
0.19
76.4
0.67
0.13
19.7
19.6
3.6
18.5
Cell-T1
Avg.
Std. Dev.
RSD
9.44
1.40
14.8
7.03
1.52
19.5
0.62
0.43
70.6
0.33
0.27
84.2
0.67
0.17
25.8
10.4
1.6
8.9
Cell-T2
Avg.
Std. Dev.
RSD
4.70
0.23
47
3.67
0.33
8.9
0.40
0.20
50.6
0.15
0.13
82.8
0.50
0.17
29.8
25.3
2.0
8.1
Overall averages
6.42
5.21| 0.44 1 0.21| 0.61| 19.6
A-2
-------
Test Cell Soil & Sand Acid-Base Accounting Results
Fraction
Method of
Extraction
Total
Sulfur
(%)
None
Pyritic
Sulfur
(%)
Hot HN03
Leach
Soluble
Sulfur
(%)
Hot
Water
Leach
Insoluble
Sulfur
(%)
HCI
Leach
Organic
Sulfur
(%)
Residual
Neutralization
Potential
(t100t)
Cell-C1
Soil
Sand
0.02
<0.01
0.02
<0.01
<0.01
<0.01
<0.01
0.02
<0.01
<0.01
135.4
<1.0
Cell - C2
Soil
Sand
0.05
0.01
0.04
0.01
<0.01
0.01
0.01
<0.01
<0.01
<0.01
146.0
3.7
Cell-T1
Soil
Sand
0.03
0.01
0.01
<0.01
0.02
<0.01
<0.01
0.01
<0.01
<0.01
143.2
<1.0
Cell-T2
Soil
Sand
0.03
0.01
0.02
<0.01
0.02
0.01
<0.01
<0.01
<0.01
<0.01
157.2
9.4
A-3
-------
Test Cell Tailings Sieve Analysis
90 00% -
80 00% -
70 00%
'
-------
Irrigation Water (Plant Water) Chemical Analysis
FIELD
ID
ENPAR-PLANTWATER
ENPAR-PLANTWATER 060304
ENPAR-PLANTWATER-071504
ENPAR-PU\NTWATER-100604
ENPAR-PLANTWATER-061605
ENPAR-PWNTWATER-083105
ENPAR-PLANTAWTER-101405
Date
Collected
10/27/2003
6/3/2004
7/150004
10/60004
6/16/2005
8/31/2005
10/14/2005
Dissolved Metals (ug/L)
Al
52.5 B
33.5 U
41.7 B
41.7 B
40.6 U
40.6 U
40 6 U
As
0.50 U
05 U
29.9 U
23.3 U
246 U
24 6 U
24 6 U
Cd
0 06 U
0.06 U
8.1 U
81 U
g 1 u
9.1 U
9.1 U
Ca
13900
14800
12900
11700
14000
14500
17000
Cu
13.3 B
20.4 B
31.8
59.8
6D
115
58.8
Fe
242
198.0
142
289
736
195
439
PI)
D.94 U
0.9 U
44. B U
44.6 U
52.3 U
52.3 U
52.3 U
Mg
5270
5870
5120
4710 B
563D
5280
5930
Mil
273
42.2
32.3
48.2
78.1
41.1
81.1
P
NR
NR
NR
NR
NR
34.9 U
34.9 U
K
2000 B
2140 B
2030 B
1920 B
2220 B
20BO B
2270 B
Si
5785
6767
6740
6610
674D
7470
7330
Na
3330 B
3380 B
3150 B
3070 B
3320 B
3670 B
4030 B
S
NR
NR
8250
8150
7720
6760
7650
Zn
7.4 B
8 U
21.6
10.7 B
923
9.07 B
10.4 B
Alkalinity
(mg CaCCVL)
36
41
38
30
42
47
51
Cl
(mg/L)
< 5
NR
< 5
< 5
< 5
CI2 Res.
(mg/L)
< 005
015
< 005
< 2
< 2
026
005
Sulfate
(mg/L)
27
28
29
NR
25
30
29
NR - parameter not requested
-------
Appendix B
Data Collection Schedule During Field Installation and Monitoring and After Test Completion
-------
Table B-l: Data Collected During Field Installation
Location
Test cells
Cl, C2,
Tl, T2
Tailings
Test cells
Cl, C2,
T1,T2
Tailings
Test cells
Cl, C2,
T1,T2
Tailings
Test cells
Cl, C2,
Tl, T2
Tailings
Test cells
Cl, C2,
Tl, T2
Tailings
Soil cover
stockpile
Quartz
sand
Parameter
Size
Distribution
Acid-Base
Accounting
Paste pH
Total Metals
Analysis
Mineralogy
Acid-Base
Accounting
Acid-Base
Accounting
Classification
Nonprimary
Primary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Frequency
One composite
sample each cell
Seven composite
samples each cell,
one split duplicate
each cell
One composite
sample each cell
One composite
sample each cell
One composite
sample each cell
One random grab
sample
One random grab
sample
Matrix
Solid
Solid
Solid
Solid
Solid
Solid
Solid
Field Measurement
or Laboratory
Analysis
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Notes:
1 . The composite sample for size distribution, paste pH, total metals, and mineralogy for each cell
will be obtained by taking one scoop of material from each "Bobcat" bucket being added to
each cell, and placing it in a 5 -gallon bucket.
2. The composite samples for acid-base accounting for each cell will be obtained as follows:
After hand distribution of approximately each vertical foot of tailings, one scoop of material
will be obtained from each quadrant of the cell. Since the tailings depth will be approximately
7.5 feet, this will provide seven composite samples each cell, each representing a vertical foot.
For the top vertical foot, this will be performed twice to provide a field duplicate for each cell.
B-l
-------
Table B-2: Data Collected During Monitoring Period
Location
Test cells Tl,
T2
Irrigation water
Test cells Cl,
C2, Tl, T2
leachate
Parameter
Galvanic voltage
Galvanic current
pH
Specific
conductance
ORP
Dissolved oxygen
Dissolved metals
Alkalinity forms
Chlorine
Sulfate
Water Volume
PH
Sulfate
Specific
conductance
Total metals
Classification
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Nonprimary
Primary
Primary
Primary
Nonprimary
Nonprimary
Frequency
Monthly
Monthly
Monthly
Monthly
Monthly
Monthly
Bimonthly
Monthly
Monthly
Monthly
Weekly
Weekly
Weekly, one
duplicate each
sampling
event
Weekly
Monthly
Matrix
~
~
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Aqueous
Field
Measurement
or Laboratory
Analysis
Field
Field
Field
Field
Field
Field
Lab
Lab
Lab
Lab
Field
Field
Lab
Field
Lab
Notes:
1 . Samples of plant service water and test cells leachate will be obtained only during time periods
when irrigation water is being applied (approximately October 2003, then April through
September 2004).
2. Metals analyte list: (Al, As, Cd, Cu, Ca, Fe, Mg, Mn, Pb, Si, Na, K, Zn)
Table B-3: Data Collected After Test Completion
Location
Test cells
Cl, C2,
Tl, T2
Test cells
Cl, C2,
Tl, T2
Test cells
Cl, C2,
Tl, T2
Parameter
Acid-Base
Accounting
Paste pH
Mineralogy
Classification
Nonprimary
Nonprimary
Nonprimary
Frequency
Three cores each
cell
Three cores each
cell
Three cores each
cell
Matrix
Solid
Solid
Solid
Field Measurement
or Laboratory
Analysis
Lab
Lab
Lab
B-2
-------
Appendix C
Quality Assurance Activities
-------
Quality Assurance and Control Activities
Mine Waste Technology Program
Activity III, Project 40
(Electrochemical Tailings Cover)
C.I REVIEW OF LABORATORY QUALIFICATIONS
The HKM Laboratory performed all the analysis for MWTP Activity III, Project 40. The laboratory is
routinely audited by the Montana Department of Public Health & Human Services (MDPHHS) for
adherence to appropriate methods and required quality control for the analysis of drinking water in the
state of Montana. Additionally, the laboratory must analyze two sets of performance evaluation samples
each year to maintain the MDPHHS drinking water certification.
Primary laboratory parameters for the demonstration are leachate sulfate, pH, and ABA of solid samples.
HKM Laboratory is certified by the MDPHHS for the analysis of sulfate and pH in drinking water; thus,
demonstrating their ability to satisfactorily perform the analysis for this project. There is no certification
program in the state of Montana for the analysis of ABA parameters; however, the laboratory routinely
analyzes blanks, control samples, and duplicates in performing ABA analysis. The control standard,
KZK-1, used for checking the accuracy of the ABA method is a certified reference material for ABA
analysis by CANMET-MMSL in Ottawa, Ontario, Canada.
C.I.I Performance Evaluation Samples
The HKM Laboratory is required to analyze performance evaluation samples twice annually to maintain
its drinking water certification by the MDPHHS. The HKM Laboratory achieved satisfactory results on
the performance evaluation for sulfate in WS-86 Study from Environmental Resource Associates
conducted from September 15, 2003 to October 30, 2003, which was at the beginning of MWTP Activity
III, Project 40. The laboratory result for sulfate in the unknown sample was 27 mg/L, which was within
the acceptance range of 21.9 to 27.6 mg/L.
There are no performance evaluation studies for ABA analyses; however, strict analytical protocol is
followed, which consists of the QA samples previously mentioned in this section.
C.2 FIELD AUDITS
One field audit was performed during the setup of the experimental cell installation. Ken Reick, a quality
assurance officer for MSB, performed the technical systems review on September 29, 2003. The scope of
the audit was to monitor compliance of loading tailings into the study cells with procedures outlined in
the QAPP. There were no findings reported, but two observations were noted:
• The first observation noted that one of the cells was nearly completely loaded without following the
alternating 1-foot loading scheme outlined in the QAPP, where 1 foot of tailings would be loaded into
a cell and then move onto the next cell and load 1 foot of tailings and sequentially move on to the
next cell until the cells contained 7 feet of uncompacted tailings. Since the tailings were considered
relatively homogeneous, this was not considered a finding.
C-l
-------
• The second observation related to the fact that no permeability testing was performed on the tailings
used in loading the test cells. Since no permeability information was available or determined, it could
not be ascertained when the cells would begin to show an accumulation of leachate water in the base
of the study cell. Obtaining such information would only allow some speculation as to when water
would appear in the test cell lysimeters, and provides no absolute basis for appearance of leach water.
Additionally, other tests such as water holding capacity would be needed to properly elucidate such a
prediction. The extent of such analysis is beyond the scope of this project and was given no further
consideration.
C.3 FIELD AND LABORATORY DATA VALIDATION
The stated objective in the QAPP was to inhibit oxidation of sulfides in sulfide-containing tailings to
minimize consequential AMD. All of the field and laboratory data was collected between September
2003 and October 2005, with the exception of the post-test ABA and 1:1 pH samples which were
submitted for analysis in October of 2006.
The effectiveness of the electrochemical tailings cover was evaluated using the results from the
installation and post-test ABA tailings analysis, leachate field measurements, and sulfate and metals
analysis from the monitoring phase. The analyses were specified in the QAPP, and each analysis was
classified as critical or noncritical. A critical analysis is an analysis that must be performed to achieve
project objectives. A noncritical analysis is an analysis that is performed to provide additional
information about the demonstration. Critical analyses for this project are summarized below.
• Installation
- tailings ABA
• Monitoring
- leachate pH
- leachate sulfate
- leachate volume
Noncritical analyses for this project are summarized below.
• Installation
- size distribution
- total metals
- paste pH
- soils ABA
- quartz sand ABA
• Monitoring
- treatment cell
- galvanic voltage
- galvanic current
- irrigation water
- pH
C-2
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- sc
- ORP
- dissolved oxygen
- dissolved metals
- alkalinity (forms)
- chlorine
- sulfate
- test cell leachate
- SC
- total metals
• Test Completion
- test cell
- ABA
- paste pH
The QA objectives for each of the critical and noncritical analysis were outlined in the QAPP and were
compatible with project objectives and methods of determination being used. The QA objectives are
accuracy, precision, completeness, and method detection limits (MDL). Requirements for each of these
objectives were established in the QAPP. The usability of the data was determined by compliance of the
data with the stated QAPP QA requirements.
C.3.1 Validation Procedures
Data generated for all critical and noncritical analyses was validated. The purpose of data validation is to
determine the usability of project data. Data validation consists of two separate evaluations: analytical
evaluation and program evaluation.
C.3.1.1 Criteria for Analytical Evaluation
Analytical evaluation was performed to determine:
- all analyses were performed within specified holding times;
- calibration procedures were followed correctly by field and laboratory personnel;
- laboratory analytical blanks contain no significant contamination;
- all necessary independent check standards were prepared and analyzed at the proper frequency
and all remained within control limits;
- duplicate sample analysis was performed at the proper frequency and all relative percent
differences (RPDs) were within specific control limits;
- matrix spike sample analysis was performed at the proper frequency and all spike recoveries
(%R) were within specified control limits; and
- the data in the report submitted by the laboratory could be verified from the raw data generated
by the laboratory.
Measurements that fall outside of the control limits specified in the QAPP or for other reasons are judged
to be outliers, and were flagged appropriately to indicate the data is judged to be estimated or unusable.
All QC outliers for all samples are summarized in Table 8-1. In addition to the analytical evaluation, a
program evaluation was performed.
C-3
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C.3.1.2 Criteria for Program Evaluation
Program evaluations include an examination of data generated during the project to determine:
- all information contained in the COC forms is consistent with the sample information in field
logs, laboratory raw data, and laboratory reports;
- all samples, including field QC samples, were collected, sent to the appropriate laboratory for
analysis, analyzed, and reported by the laboratory for the appropriate analyses;
- all field blanks contained no significant contamination; and
- all field duplicate samples demonstrate precision for field and laboratory procedures by remaining
within the established RPD control limits.
Program data that was inconsistent or incomplete and did not meet the QC objectives outlined in the
QAPP were viewed as outliers and were flagged appropriately to indicate the usability of the data. Both
the analytical and program evaluations consisted of evaluating the data generated in the field as well as in
the laboratory.
C.3.2 Analytical Evaluation
The analytical evaluation of field and laboratory data was done in December 2005. Analytical and field
data were validated by the MSB Quality Assurance Officer (QAO), Michelle Lee.
C. 3.2.1 Field Logbook Evaluation
Field data validation began with an examination of the field logbooks. All project information was
recorded in two, bound all-weather transit-style 4.75-inch by 7-inch notebooks. Additional notes, SOPs,
and field sheets were retained in a project-dedicated 3-inch, 3-ring binder.
Information about Fieldwork Performed
The general logbooks contained notes on fieldwork performed and process measurements. Voltage and
current readings from the treatment cells were periodically recorded, to ensure that the technology in the
treatment cells was properly functioning. Water level measurements from each test cell were sporadically
recorded, but these measurements were only necessary to indicate that the artificial water table was
established. Leachate volumes were difficult to correlate between the logbook records and the sulfate
analytical data; however, data correlation was reconstructed based on the dates recorded.
C.3.2.2 Field Data Validation
Field data validation was performed to determine the usability of the data that was generated during field
activities. Data usability was determined by verifying correct calibration procedures for field instruments
were followed. In addition, the QC parameters of precision and accuracy calculated in the field were
compared to those specified in the QAPP. Any data that fell outside of the control limits was considered
outlier and was flagged appropriately. The measurements performed in the field were:
- amount of test cell leachate pumped (critical);
- test cell well depth (noncritical);
- leachate pH (critical);
- temperature (noncritical);
- ORP (noncritical);
- dissolved oxygen (noncritical); and
C-4
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- SC (noncritical).
C.3.2.3 Sample Collection
Samples were collected by the project manager and engineer during the project. The technical systems
review performed by Ken Reick in September 2003 during setup of the experimental installation, revealed
no sample collection findings.
C. 3.2.4 Sample Labeling
Samples were labeled in accordance with the scheme outlined in the QAPP. Labeling followed the
described format ensuring that each sample was given a unique sample identification number.
C.3.2.5 Sample Packing and Transport
Due to the proximity of the test installation and the laboratory, samples were hand-delivered to the
laboratory, typically within 24 hours of collection. However, in a couple instances, soil samples were
delivered to the laboratory several days after collection, but the delay is considered inconsequential, since
there is no technical holding time for soils analysis.
Amount of Test Cell Leach ate Pumped
The amount of leachate pumped was measured by collection in graduated tanks and/or weighed. The data
was not systematically recorded, making it difficult to correlate with the appropriate analytical sulfate
results. Due to this shortcoming, the amount of leachate pumped was considered to be of screening use
only.
pH
The pH meter was calibrated using two known buffer solutions. Typically, the buffer solutions would
bracket the measured pH. The accuracy of the pH meter was verified by measuring a third known buffer
within the calibration range. Accuracy was defined as the absolute difference between the measured and
known buffer value. Calibration was performed each day pH measurements were taken. All pH data was
considered usable.
Temperature
Temperature was recorded on the pumped leachate water samples and irrigation water (i.e., plant water)
used to augment the natural precipitation. All temperatures were recorded in the project logbooks. All
temperature data was considered usable.
Oxidation-Reduction Potential
ORP was performed on the leachate water and irrigation water samples. The accuracy of the ORP was
verified by measuring Zobell's solution of a known ORP. The measured ORP was required to be within
20 mV of the temperature specified value for the Zobell's solution. All readings were within the required
accuracy range so all ORP values were considered usable.
Dissolved Oxygen
Dissolved oxygen was measured on the leachate and plant water samples. The dissolved oxygen was
calibrated each time the meter was used. There was no known standard solution used to verify the
dissolved oxygen measurements. Since the meter was calibrated at the required frequency, all dissolved
oxygen measurements were considered usable.
C-5
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Specific Conductance
The SC was measured on leachate and plant water samples. The SC was calibrated daily as specified in
the QAPP. Since the SC was calibrated as specified, all SC data was considered usable.
C.3.2.6 Laboratory Data Validation
Laboratory data validation was performed to determine the usability of the data that was generated by the
laboratory for this project. The laboratory was reviewed and validated by the MSB QAO in December
2005, after the dismantling of the demonstration. The analyses performed by the HKM Laboratory were:
- ABA (critical);
- sulfate (critical);
- paste pH (noncritical);
- total and dissolved metals (noncritical);
- alkalinity, forms (noncritical);
- chlorine (noncritical); and
- sieve analysis (noncritical).
Laboratory validation was performed using the quality assurance objectives defined the QAPP for the
critical parameters ABA and sulfate. Evaluation of total and dissolved metals analysis was performed
using the quality control requirements of the Contract Laboratory Program (CLP) Statement of Work
(SOW)ILMOl.l.
Acid-Base Accounting
Acid-base accounting was performed according to the protocols in Method 3.2.6 from EPA-600/2-78-
054. Laboratory and field duplicates were prepared at the frequency required in the QAPP. All of the
ABA data was considered usable. Evaluation of the ABA data was based on compliance with duplicate
precision, accuracy of laboratory control samples, and analyte levels in preparation blanks. In summary,
there were no issues with accuracy or contamination. ABA data was flagged because of lack of precision
in laboratory and field duplicates only. The duplicate (precision) control limits assigned in the QAPP are
quite stringent; typically, the RPD limit of 35% is used to evaluate solid matrix samples. Table C-l
outlines the samples and the associated flags.
During analysis of the installation tailings samples, the HKM Laboratory encountered some difficulty in
ABA analysis. This prompted the project manager to submit a batch of samples to a referee laboratory,
Silver Valley Laboratory (SVL) for ABA analysis. A comparison of the ABA results is presented in
Table C-2. The results compare reasonably well except for the values from treatment cell Tl. HKM
Laboratory had high total sulfur results from cell Tl compared to SVL results; however, duplicate
analysis results from SVL displayed a large imprecision. It can only be concluded that cell Tl was not as
homogeneous as the other test cells. Further scrutiny of the sulfur fractions revealed that the HKM
Laboratory showed excellent agreement between the total sulfur and summation of the sulfur fractions;
whereas, SVL displayed significant discrepancies between the total sulfur and corresponding fraction
summations. The HC1 extractable sulfur values from SVL were consistently higher than HKM, while the
residual sulfur values from HKM were consistently higher than SVL results.
Leachate Sulfate
Sulfate analysis was performed by the HKM Laboratory. All sulfate data was considered usable.
However, one sulfate value that appeared to be discrepant. The sulfate value for cell T2 sampled on
October 6, 2004 seems to be low. The value does not correlate well with inductively coupled plasma
C-6
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(ICP) determined sulfur values. Additionally, there is no corresponding decrease in the SC, as would be
expected for such a dramatic drop in the sulfate concentration. All field duplicates complied with the
precision requirements of the QAPP, as can be seen in Table C-3.
Paste pH
Saturated paste pH and 1:1 paste pH analysis was performed by the methods found in the Methods of Soil
Analysis, Part 2, American Society of Agronomy (1982). All data met criteria established in the QAPP.
All soil pH data was considered usable.
Total and Dissolved Metals
Total and dissolved metals data was provided by the HKM Laboratory. Select soils/tailings and waters
were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). All data was
validated. Silicon was found in the laboratory preparation blanks; however, no data was flagged for
silicon since all sample concentrations were greater than ten times the levels found in the blanks.
Aluminum, copper, and silicon data from the installation tailings composite samples were flagged as
estimated because of matrix spike recoveries outside the 75-125% recovery limit in the QAPP. Lead was
flagged because of low matrix spike recovery in the final leachate samples taken on October 14, 2005.
Flagged samples are shown in Table C-l. All metals data was considered usable given the previously
cited constraints.
Remaining Analysis
Alkalinity, chlorine residual, and sieve analysis data was also reviewed. All data was considered usable
and requires no qualification.
C.3.3 Program Evaluation
Program evaluation focused on:
- COC procedures;
- sampling and data completeness;
- field blanks; and
- field duplicates.
C.3.3.1 COC Procedures
All information provided in the COC forms for this project was complete and accurate, with the following
exceptions.
• The tailings composite samples taken on September 25, 2003 had no time sampled provided. The
time sampled should accompany every sample.
• The referee samples sent to SVL on May 24, 2004 had no date or time sampled provided. The date
and time sampled should always be provided with a referee sample so correct and proper comparisons
can be made.
• The cell leachate and irrigation water samples taken on October 6, 2004, did not have a time sampled
provided. Again, the time sampled should accompany each sample to aid in identification.
C-7
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C.3.3.2 Sampling and Data Completeness
Samples were collected and analyzed for all the parameters and during all phases (field installation,
monitoring, and after test completion), except for mineralogy. Mineralogy was not a critical parameter
and was omitted from both the initial and final phases. Saturated past pH analysis was completed on
composite samples for the installation samples. Instead of paste pH on the test completion samples, 1:1
pH was substituted due to the limited amount of sample available in the cores.
The sampling frequency was dramatically relaxed after the decision was made to extend the project for a
year. It was determined that the kinetics of the processes would not require the frequency initially stated
in the QAPP and no compromise would occur as a result of the reduced sampling frequency.
C.3.3.3 Field QCSamples
All field QC samples were collected at the proper frequency for the tests specified in the QAPP. Sulfate
was the analyte of primary concern so several field duplicates were collected throughout the project. A
duplicate was not collected each sampling event; however, instructions were given and recorded on the
COC for the laboratory to use a specific sample for QA/QC to ensure that each leachate collection
location had several QC samples. The field duplicate results for sulfate were all within 20% RPD, so
none of the samples were qualified.
C.3.3.4 FieldBlanks
Field blanks were collected and analyzed for ABA analysis. Sand was designated as the field blank for
ABA analysis. The results for the sand were all at or below the detection for total sulfur and the various
sulfur fractions. No leachate sulfate field blanks were taken or defined in the QAPP. The leachate sulfate
concentration was sufficiently high to virtually guarantee that the results would not be affected by low-
level contamination. Laboratory blanks indicated that there was indeed no low or high-level sulfate
contamination introduced by the laboratory. The sulfate values were not qualified.
No field blanks were prescribed in the QAPP or submitted for any of the other analysis.
C. 3.3.5 Field Duplicates
Field duplicates for leachate sulfate all showed very good agreement.
Total sulfur for the tailings from the test cell installation ABA results had reasonable agreement (Table C-
2). The cell C2 duplicate RPD was 28.5%, which is less than a typical 35% RPD limit for solid matrix
samples. Field duplicate results for ABA total sulfur from the referee tailings samples sent to SVL were
all acceptable except from treatment cell Tl, which had 60.6% RPD.
Analysis of the ABA sulfur fractions (forms) had several results with RPDs in excess of 20%. The large
variation in the sulfur fractions is not unusual, since these values are determined by difference.
C.4 QA/QC SUMMARY
Analytical laboratory results for ABA, leachate sulfate, pH, and other analysis are located in Appendix A.
The majority of the findings with the analytical data and program evaluation are minor for this project.
Several installation tailings ABA results where qualified. Leachate recordkeeping on the leachate volume
was inconsistent and not clearly recorded.
C-8
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C.4.1 ABA Analysis
The ABA analysis provided a challenge for the HKM Laboratory. Preliminary data did not provide
acceptable agreement between total sulfur and the forms of sulfur. It was determined that further size
reduction of the sample was necessary to achieve acceptable results. In order to obtain satisfactory
results, the sample particle size had to be reduced to less than 100 mesh. This is significantly finer than
the 60-mesh sample size specified in the method. The delay in receiving results and communications
from the laboratory prompted the project manager to seek referee ABA analysis from SVL. Results were
variable between the laboratories, but seemed comparable.
The ABA analysis was qualified mainly for imprecision in laboratory and field duplicates. This is the
result of two factors, the first being the project precision requirement of < 20% RPD is more limiting than
a 35% RPD often assigned soil samples in other QA programs. Secondly, the ABA fractions were often
qualified. The general reason for this is due to ABA fractions being calculated from two separate
analyses and the error being a function of multiple determinations. Since each determination contributes
uncertainty to the final result, the more determinations involved in the result increases the uncertainty;
therefore, it is more likely the duplicate result will exceed the RPD criteria.
C.4.2 Leachate Volume
The leachate volume was established as a critical parameter to measure the success of the cover
technology being tested in this demonstration. There appeared to be no systematic means to record the
volume of leachate being pumped from each test cell. The leachate volume measurements were recorded
in field logbook; however, there was no direct correlation between the volume data from the logbook and
appropriate laboratory analytical data; therefore, accuracy in calculating the mass of sulfate leaching from
each cell was compromised. To help clarify this type of data collection in future projects, it would be
advisable to formulate a specific logbook or log sheet that requires the essential information to be
recorded for each event.
C-9
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Table C-l. Summary ofQA Outliers
Date Sample ID
9/25/2003 ENPAR-C2-TAILS-1-0925
ENPAR-C2-TAILS-1D-0925
ENPAR-C2-TAILS-2-0925
ENPAR-C2-TAILS-3-0925
ENPAR-C2-TAILS-4-0925
ENPAR-C2-TAILS-5-0925
ENPAR-C2-TAILS-6-0925
ENPAR-C2-TAILS-7-0925
ENPAR-C-SOIL-0926
ENPAR-C-SAND-0925
9/25/2003 ENPAR-T1-TAILS-1-0925
ENPAR-T1-TAILS-1D-0925
ENPAR-T1-TAILS-2-0925
ENPAR-T1-TAILS-3-0925
ENPAR-T1-TAILS-4-0925
ENPAR-T1-TAILS-5-0925
ENPAR-T1-TAILS-6-0925
ENPAR-T1-TAILS-7-0925
ENPAR-T1-SOIL-0926
ENPAR-T1-SAND-1-0925
9/25/2003 ENPAR-T1-TAILS-1-0925
ENPAR-T1-TAILS-1D-0925
ENPAR-T1-TAILS-2-0925
ENPAR-T1-TAILS-3-0925
ENPAR-T1-TAILS-4-0925
ENPAR-T1-TAILS-5-0925
ENPAR-T1-TAILS-6-0925
ENPAR-T1-TAILS-7-0925
ENPAR-T1-SOIL-0926
ENPAR-T1-SAND-1-0925
Lab ID Analysis QC Criteria Control Limit
0310200001 Hot Water Lab Duplicate 20% RPD
0310200002 Extractable
0310200003 SulfUI
0310200004
0310200005
0310200006
0310200007
0310200008
0310200009
0310200010
0310200021 HC1 Extractable Lab Duplicate 20% RPD
0310200022 Sulfur
0310200023
0310200024
0310200025
0310200026
0310200027
0310200028
0310200029
0310200030
0310200021 Residual Sulfur Lab Duplicate 20% RPD
0310200022
0310200023
0310200024
0310200025
0310200026
0310200027
0310200028
0310200029
0310200030
Result Flag* Comment
60.0% RPD J Control limit
established in
the QAPP
52.4% RPD J Control limit
established in
the QAPP
31.9% RPD J Control limit
established in
the QAPP
-------
Date Sample ID
9/25/2003 ENPAR-C 1 -TAILSCOMPOSITE-0925
ENPAR-C2-TAILSCOMPOSITE-0925
ENPAR-T1-TAILSCOMPOSITE-0925
ENPAR-T2-TAILSCOMPOSITE-0925
9/25/2003 ENPAR-C 1 -TAILSCOMPOSITE-0925
ENPAR-C2-TAILSCOMPOSITE-0925
ENPAR-T1-TAILSCOMPOSITE-0925
ENPAR-T2-TAILSCOMPOSITE-0925
9/25/2003 ENPAR-C 1 -TAILSCOMPOSITE-0925
ENPAR-C2-TAILSCOMPOSITE-0925
ENPAR-T1-TAILSCOMPOSITE-0925
ENPAR-T2-TAILSCOMPOSITE-0925
10/14/2005 ENPAR-T1-101405
ENPAR-T2-101405
ENPAR-C 1-1 01405
ENPAR-C2-1 01405
10/26/2005 ENPAR-EFFTANK-102605
9/25/2003 ENPAR-Cl-TAILS-1-0925
ENPAR-C 1 TAILS- 1D-0925
ENPAR-C 1 -TAILS-2-0925
ENPAR-C 1 -TAILS-3-0925
ENPAR-C 1 -TAILS-4-0925
ENPAR-C 1 -TAILS-5-0925
ENPAR-C 1 -TAILS-6-0925
ENPAR-C 1 -TAILS-7-0925
ENPAR-C l-SOIL-0926
ENPAR-C 1 -SAND-0925
Lab ID Analysis QC Criteria
0310200041 Aluminum in soil Matrix Spike
0310200042
0310200043
0310200044
0310200041 Copper in soil Matrix Spike
0310200042
0310200043
0310200044
0310200041 Silicon in soil Matrix Spike
0310200042
0310200043
0310200044
051017J002 Lead Matrix Spike
051017J003
051017J004
051017J005
0510270650
03 1 020O03 1 HC1 Extractable Field Duplicate
0310200032 Sulfur, HN03
Extractable
0310200033 Sulfur &
03 1 0200034 Residual Sulfur
0310200035
0310200036
0310200037
0310200038
0310200039
0310200040
Control Limit Result Flag* Comment
75-125% 374. 5 %R J Control limit
recovery (%R) established in
the QAPP
75-125 %R 127.5 %R J Control limit
established in
the QAPP
75-125 %R 157.7%R J Control limit
established in
the QAPP
75-125 %R 69.7 %R J Control limit
established in
the QAPP
20% RPD 64.0% RPD, J Control limit
24.6% RPD, & established in
53. 3% RPD the QAPP
-------
Date
9/25/2003
9/25/2003
9/25/2003
Sample ID
ENPAR-C2-TAILS-1-0925
ENPAR-C2TAILS-1D-0925
ENPAR-C2-TAILS-2-0925
ENPAR-C2-TAILS-3-0925
ENPAR-C2-TAILS-4-0925
ENPAR-C2-TAILS-5-0925
ENPAR-C2-TAILS-6-0925
ENPAR-C2-TAILS-7-0925
ENPAR-C2-SOIL-0926
ENPAR-C2-SAND-0925
ENPAR-T1-TAILS-1-0925
ENPAR-T1TAILS-1D-0925
ENPAR-T1-TAILS-2-0925
ENPAR-T1-TAILS-3-0925
ENPAR-T1-TAILS-4-0925
ENPAR-T1-TAILS-5-0925
ENPAR-T1-TAILS-6-0925
ENPAR-T1-TAILS-7-0925
ENPAR-T1-SOIL-0926
ENPAR-T1-SAND-0925
ENPAR-T2-TAILS-1-0925
ENPAR-T2TAILS-1D-0925
ENPAR-T2-TAILS-2-0925
ENPAR-T2-TAILS-3-0925
ENPAR-T2-TAILS-4-0925
ENPAR-T2-TAILS-5-0925
ENPAR-T2-TAILS-6-0925
ENPAR-T2-TAILS-7-0925
ENPAR-T2-SOIL-0926
ENPAR-T2-SAND-0925
Lab ID
0310200001
0310200002
0310200003
0310200004
0310200005
0310200006
0310200007
0310200008
0310200009
0310200010
0310200021
0310200022
0310200023
0310200024
0310200025
0310200026
0310200027
0310200028
0310200029
0310200030
0310200011
0310200012
0310200013
0310200014
0310200015
0310200016
0310200017
0310200018
0310200019
0310200020
Analysis QC Criteria
Total Sulfur, Hot Field Duplicate
Water
Extrac table
Sulfur, HC1
Extrac table
Sulfur, HN03
Extrac table
Sulfur, &
Residual Sulfur
Hot Water Field Duplicate
Extrac table
Sulfur, HC1
Extrac table
Sulfur, &
Residual Sulfur
Hot Water Field Duplicate
Extrac table
Sulfur, &
Residual Sulfur
Control Limit Result Flag* Comment
20% RPD 28. 5% RPD, J Control limit
44 .4% RPD, established in
25. 6% RPD, the QAPP
34.5% RPD, &
23. 9% RPD
20% RPD 68.1% RPD, J Control limit
1 04 .4% RPD, established in
& 24.0% RPD the QAPP
20% RPD 42. 4% RPD, & J Control limit
64 .4% RPD established in
the QAPP
* J - estimated
-------
Table C-2. ABA Field Duplicate Summary/Comparison, HKM Lab vs. SVL
Hot HC1 Sum of
HNO3 Water Extractable Sulfur
Extractable Extractable Sulfur Residual Sum of Fractions
Total Sulfur Sulfur (Insoluble Sulfur Sulfur -Total
Sulfur (Sulfide (Sulfate Sulfide (Organic Fractions Sulfur
Cell Lab Field ID (%) Sulfur-%) Sulfur-%) Sulfur-%) Sulfur-%) (%) (%)
i-H
U
HKM
ENPAR-C 1 -TAILS-1 -0925
ENPAR-C 1 TAILS- 1D-0925
RPD
5.80
6.68
14.1%
4.52
5.79
24.6%
0.38
0.38
0.4%
0.22
0.11
64.0%
0.68
0.39
53.3%
5.80
6.68
14.1%
SVL
C1-3-A
C1-3-B
RPD
5.55
5.01
10.2%
4.67
3.85
19.2%
0.83
1.12
29.7%
1.57
2.01
24.6%
0.05
0.04
22.2%
7.12
7.02
1.4%
0.00
0.00
1.57
2.01
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Table C-3. Leachate Sulfate Field Duplicates
Sample ID
041007L001
041007L005
051017J004
051017J006
040706M007
040706M010
040628K001
040628K005
050616Q004
050616Q006
0508310004
0508310006
04071 5P005
040715P006
Field ID
ENPAR-C 1-1 00604
ENPAR-C1-D-100604
ENPAR-C1-101405
ENPAR-C1-D-101405
ENPAR-C2-070104
ENPAR-C2-D-070104
ENPAR-T1-062304
ENPAR-T1-D-062304
ENPAR-T1-061605
ENPAR-T1D-061605
ENPAR-T1-083105
ENPAR-T1-D-083105
ENPAR-T2-071504
ENPAR-T2-D-071504
Test Cell Date
ID Collected
C1 10/6/2004
10/6/2004
C1 10/14/2005
10/14/2005
C2 7/1/2004
7/1/2004
11 6/23/2004
6/23/2004
11 6/16/2005
6/16/2005
11 8/31/2005
8/31/2005
12 7/15/2004
7/15/2004
Time
Collected
14:15
14:40
10:45
10:45
9:25
9:25
13:10
13:10
10:20
10:20
8:45
8:45
Sulfate
(mg/L)
6641
6376
5065
4953
9115
8862
9476
9283
8672
8918
8214
7354
12258
12035
RPD
4.1%
2.2%
2.8%
2.1%
2.8%
11.0%
1.8%
C-14
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