Appendix I - TSF_Water Quality Modeling_PFS_Rev03_20240418

Technical Report
2023 Prefeasibility Study, Kings Mountain
Mining Project
Archdale Tailings Storage Facility Water
Quality Predictions
Effective Date: April 18, 2024
Report Date: April 18, 2024
Report Prepared for
A ALBEMARLE"
Albemarle Corporation
4250 Congress Street
Charlotte, NC 28209
Report Prepared by
.srk consulting
SRK Consulting (U.S.), Inc.
999 17th Street, Suite 400
Denver, CO 80202
SRK Project Number: USPR000576
Signed by Qualified Persons:
Ruth Griffiths, Principal Consultant(Geochemistry)
Reviewed by:
Amy Prestia, Principal Consultant (Geochemistry)
Rob Bowell, Corporate Consultant(Geochemistry and Geometallurgy)

SRK Consulting(U.S.), Inc.
2023 PFS Report—Water Quality Predictions for the Archdale Project Page i
Executive Summary
The Kings Mountain Mining Project (KMMP or Project) is a historical open pit lithium (Li) mining
operation located in the city of Kings Mountain, North Carolina, in the southeastern United States. The
Project is a lithium pegmatite deposit that is currently being investigated for redevelopment by
Albemarle Corporation (Albemarle) as part of a prefeasibility-level analysis.
The Project will generate tailings material that will be disposed of at the proposed Archdale tailings
storage facility (TSF) located approximately 3 miles south of the Project. The TSF will be built within
the existing open pits at Archdale and will have a surrounding embankment consisting of newly
excavated non-potential acid generating (non-PAG) waste rock from the Kings Mountain pit. The
filtered tailings material will be placed and compacted within the storage facility with mobile equipment.
Over the life of the Project, the TSF embankment will be raised, and the filtered tailings will continue
to be placed until the facility reaches its capacity.At final build-out the TSF will contain 9.2 million short
tons (Mst) of tailings, after which it will be closed and reclaimed.
The purpose of this study is to determine the quality of contact waters associated with the Archdale
TSF and to inform water management requirements for the Project. This work forms part of the
geochemistry baseline study being conducted to assess the Acid Rock Drainage and Metal Leaching
(ARDML) potential of the Project.
Site-specific information from the water balance, groundwater model, mine plan, geologic model,
geochemical characterization program and onsite water quality monitoring have been used to develop
an integrated conceptual model for the Archdale TSF. The conceptual models developed for the
Archdale TSF provide the basis for the development of the water quality predictions. The general
approach for modeling water quality for the facility is to quantify annual solute concentrations in:
• Contact waters that will run off the tailings surface prior to cover placement and report to the
contact water pond. After cover placement, any runoff waters are assumed to only contact the
reclamation cover and will be non-contact water.
• Meteoric waters that will infiltrate the tailings and report to the drains at the base of the TSF and
be pumped to the contact water pond during operations.
• Meteoric water that will enter the waste rock perimeter berm either through infiltration or 'as
groundwater flow.This water will either report to the drains at the base of the TSF and get pumped
to the contact water pond, or report as toe seepage.
• Groundwater underneath the facility (incorporates loading from both the tailings and surrounding
waste rock embankment).
• Water quality in the seepage collection drain (SCD;also referred to as a trench in design drawings)
adjacent to the TSF, which will receive toe seepage from the base of the embankment, plus a
proportion (approximately 90%) of seepage from the TSF and embankment that reports to the
shallow groundwater system and migrates to the SCD. The remaining approximate 10% of
seepage is assumed to bypass the SCD and report to Archdale Creek over long time spans
through low conductivity saprolite and deep bedrock(SRK, 2024c).
• Water quality in the contact water pond (operations only), which will receive water from the SCD,
TSF sumps and from direct precipitation on the pond surface.
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• Water quality in Archdale Creek. This is primarily assumed to be fed by base groundwater flow,
plus approximately 10% of the seepage from the TSF and embankment that bypasses the SCD.
Post-closure, Archdale Creek will also receive flow directly from the SCD.
Representative leachate chemistry data for the future tailings material were obtained from modified
Synthetic Precipitation Leaching Procedure(SPLP)testing using deionized water(US EPA, 1994)and
United States Environmental Protection Agency (US EPA) Leaching Environmental Assessment
Framework (LEAF) testing using the 1313 method (US EPA, 2012). These tests were carried out on
two composite samples (COMP1 and COMP2)obtained from the 2023 Met Program. The EPA LEAF
1313 test results at pH 7 were used, as these are the most representative of the pH conditions
expected in the future TSF based on the HCT program. The results were scaled to field conditions
using the parameter-specific calibration factors developed as part of the calibration model for the Kings
Mountain existing TSF (i.e., the legacy facility constructed during the historical operation), described
herein. Representative leachate chemistry data for the non-PAG waste rock used in the TSF
embankment construction were derived from the results of the ongoing humidity cell test (HCT)
program. Standard industry approaches include developing a scaling factor that is applied to the
laboratory HCT data to account for the differences in reaction masses, reaction rates,temperature and
liquid-to-solid ratios between the laboratory test and expected field conditions. Site-specific scaling
factors were developed based on information relating to the water balance, geological model and mine
plan. Representative groundwater chemistry in the vicinity of the Archdale TSF was obtained from
samples collected by SRK as part of the Archdale field and drilling campaign in December 2023. In
the absence of site-specific precipitation chemistry data,the chemistry of representative rainwater was
obtained from the Piedmont Research Station in Rowan County approximately 85 km from the Project
area.
The base case water quality predictions use a mass balance approach, whereby the tailings, waste
rock and groundwater source terms are mixed in the proportions provided in the water balance at the
various water quality prediction points. This is considered a conservative approach, as mineral
precipitation and trace element sorption processes (i.e., natural geochemical processes that may
remove trace elements from solution and will likely occur)are not accounted for.A sensitivity analysis
is included to evaluate the effect of incorporating mineral precipitation and sorption on the resulting
water chemistry.
The modeling results show that water quality in the contact water pond and Archdale Creek, is
predicted to be circum-neutral (pH 6.7 to 7.4),with all parameters predicted to be below North Carolina
Department of Environmental Quality (NCDEQ) Class C Surface Water Standards. Post-closure, the
contact water pond will no longer be operational. Groundwater underlying the proposed TSF is also
predicted to be circum-neutral (pH 6.7 to 7.3), with the majority of parameters predicted to be below
NCDEQ Groundwater Quality Standards during operations and closure. The only exceptions are iron
and manganese,which are elevated in existing (i.e., baseline)groundwater at Archdale(SRK, 2024b).
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Table of Contents
1 Introduction.................................................................................................................. 1
1.1 Objectives of the Study.......................................................................................................................1
2 Background.................................................................................................................. 2
2.1 Property Location................................................................................................................................2
2.2 Project Overview.................................................................................................................................3
2.2.1 Archdale Tailings Facility.........................................................................................................3
2.3 Previous Mining...................................................................................................................................5
3 General Setting ............................................................................................................ 6
3.1 Topography and Morphology..............................................................................................................6
3.2 Surface Water Features......................................................................................................................6
3.3 Project Climate....................................................................................................................................8
3.3.1 Temperature............................................................................................................................8
3.3.2 Precipitation.............................................................................................................................8
3.3.3 Evaporation .............................................................................................................................9
3.4 Regional Geology..............................................................................................................................10
3.5 Groundwater and Surface Water Quality..........................................................................................12
4 Geochemical Characterization Summary ................................................................ 15
4.1 Future Tailings ..................................................................................................................................15
4.2 TSF Embankment.............................................................................................................................16
4.3 Archdale Bedrock and Pit Wall Rock................................................................................................17
4.4 Cover Material (Saprolite and Alluvium) ...........................................................................................18
5 Kings Mountain Existing TSF Calibration Model..................................................... 19
6 Archdale TSF Water Quality Predictions ................................................................. 22
6.1 Conceptual Model .............................................................................................................................22
6.2 Data Sources ....................................................................................................................................26
6.3 TSF Composition ..............................................................................................................................26
6.4 Waste Rock Embankment Composition ...........................................................................................27
6.5 Water Balance...................................................................................................................................27
6.6 Chemistry Inputs...............................................................................................................................29
6.6.1 Precipitation Chemistry .........................................................................................................29
6.6.2 Tailings Chemistry.................................................................................................................31
6.6.3 Waste Rock Embankment Chemistry ...................................................................................32
6.6.4 Derivation of Rock Weathering and Leaching Rates for Embankment.................................32
6.6.5 Groundwater Chemistry ........................................................................................................38
6.7 Nitrate Leaching from TSF Embankment..........................................................................................39
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6.8 Equilibration Sensitivity Analysis.......................................................................................................39
6.9 Model Results ...................................................................................................................................40
6.9.1 Base Case.............................................................................................................................40
6.9.2 Equilibration Sensitivity Analysis...........................................................................................41
7 Summary..................................................................................................................... 48
8 References.................................................................................................................. 49
Disclaimer........................................................................................................................ 50
Copyright ......................................................................................................................... 50
List of Tables
Table 5-1: Kings Mountain Existing TSF Calibration Results...........................................................................21
Table 6-1: Archdale TSF Model Data Sources.................................................................................................26
Table 6-2: TSF Embankment Tonnage and Lithological Composition.............................................................27
Table 6-3: Average Flows During the Operational and Post-Closure Periods.................................................28
Table 6-4: Piedmont Research Station Precipitation Data - 2011 to 2021.......................................................29
Table 6-5: Tailings Source Term used in Archdale TSF Model (Scaled to Field Conditions)..........................31
Table 6-6: Humidity Cells used to Develop Source Terms for Non-PAG Waste Rock in TSF Embankment..36
Table 6-7: Non-PAG Waste Rock HCT Source Terms used in Archdale TSF Model (Unscaled)...................37
Table 6-8: Groundwater Chemistry used in Archdale TSF Model....................................................................38
Table 6-9: Mineral Equilibrium Phases used in the Equilibration Sensitivity Analysis.....................................40
Table 6-10: Predicted Groundwater Quality Underlying the Archdale TSF (Base Case) ................................42
Table 6-11: Predicted Water Quality in the Archdale TSF Contact Water Pond (Base Case).........................43
Table 6-12: Predicted Water Quality in Archdale Creek (Base Case) .............................................................43
Table 6-13: Predicted Groundwater Quality Underlying the Archdale TSF (Equilibrium Sensitivity Analysis) 44
Table 6-14: Predicted Water Quality in the Archdale TSF Contact Water Pond (Equilibrium Sensitivity
Analysis) ..............................................................................................................................................46
Table 6-15: Predicted Water Quality in Archdale Creek (Equilibrium Sensitivity Analysis) .............................47
List of Figures
Figure 2-1: Project Location Map .......................................................................................................................2
Figure 2-2: Preliminary Site Layout....................................................................................................................4
Figure 2-3: Previous Usage of the TSF Area .....................................................................................................5
Figure 3-1: Location of Kings Creek Watershed.................................................................................................7
Figure 3-2: Annual Precipitation and Distribution of Monthly Precipitation ........................................................9
Figure 3-3: Average Monthly Evaporation........................................................................................................10
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Figure3-4: Surface Geology.............................................................................................................................11
Figure 3-5: Archdale Surface Water Sample Locations...................................................................................13
Figure 3-6: Archdale Groundwater Sample Locations .....................................................................................14
Figure 4-1: Legacy TSF Lysimeter Locations...................................................................................................16
Figure 6-1: Archdale TSF Conceptual Model - Operations..............................................................................24
Figure 6-2: Archdale TSF Conceptual Model — Post-Closure..........................................................................25
Figure 6-3: pH Trends at Piedmont Research Station (NADP, 2022)..............................................................30
Figure 6-4: Sulfate Trends at Piedmont Research Station (NADP, 2022).......................................................30
Figure 6-5: Chloride Trends at Piedmont Research Station.............................................................................31
Figure 6-6: Cross-section Showing Reactive Rim of Waste Rock Particle......................................................33
Appendices
Appendix A: Annual Water Quality Predictions (Base Case)
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Glossary of Terms
Abbreviation Unit or Term
ABA Acid Base Accounting
ARDML Acid Rock Drainage and Metal Leaching
bgs Below ground surface
DIMS Dense Media Separation
EPA Environmental Protection Agency
HCT Humidity Cell Test
HDPE High Density Polyethylene
LEAF Leaching Environmental Assessment Framework
MAP Mean Annual Precipitation
Mg/kg Milligrams per kilogram
Mg/L Milligrams per liter
Mst Million short tons
NADP National Atmospheric Deposition Program
NAG Net Acid Generation
Non-PAG Non-Potentially Acid Generating
NP Neutralizing Potential
NPR Neutralizing Potential Ratio
PAG Potentially Acid Generating
PSD Particle Size Distribution
RSF Rock Storage Facility
SCD Seepage Collection Drain
SPLP Synthetic Precipitation Leaching Procedure
TDS Total Dissolved Solids
TSF Tailings Storage Facility
TSS Total Suspended Solids
UT Unnamed Tributary
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1 Introduction
The Kings Mountain Mining Project (the Project) is an historical open pit lithium (Li) mining operation
located in the city of Kings Mountain, North Carolina, in the southeastern United States. The Project
is a lithium pegmatite deposit that is currently being investigated for redevelopment by Albemarle
Corporation (Albemarle) as part of a prefeasibility-level analysis. Albemarle commissioned SRK
Consulting (U.S.), Inc. (SRK) to develop prefeasibility-level designs for an expansion of the existing
pit, waste rock management, water management, and ancillary infrastructure to aid Albemarle in
making informed decisions concerning advancement of the Project. The Project will generate tailings
material that will be disposed of at the Archdale tailings storage facility (TSF) located approximately 3
miles south of the Project.
1.1 Objectives of the Study
The purpose of this study is to determine the quality of contact waters associated with the Archdale
TSF and to inform water management requirements for the Project. This work has been undertaken
on behalf of Albemarle and forms part of the geochemistry baseline study being conducted to assess
the Acid Rock Drainage and Metal Leaching (ARDML) potential of the Project (SRK, 2024a and SRK
2024b).
Site-specific information from the water balance, groundwater model, mine plan, geologic model,
geochemical characterization program and onsite water quality monitoring have been used to develop
an integrated conceptual model for the Archdale TSF. The conceptual model was used as a basis for
developing quantitative water quality predictions.
The purpose of this report is to present the conceptual model, to provide a description of the inputs
and assumptions used for the water quality predictions, and to present the results.
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2 Background
2.1 Property Location
Situated in Cleveland County, the mine is approximately 35 miles west of Charlotte, North Carolina.
Located amidst rolling hills of the Piedmont Plateau, the Project is in a predominantly rural setting
within the city of Kings Mountain. The mine site covers a significant area of land, which includes both
the proposed extraction areas and associated processing infrastructure. Figure 2-1 shows the location
of the mine and the location of the Archdale TSF.
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.E SRK=3 — 10i KINGS MOUNTAIN MINING PRCJi 1,1
r«F Fig 1-1 Project W"J.n a.USPRMD576
Source:SRK,2024a
Figure 2-1: Project Location Map
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2.2 Project Overview
The Project ore deposit is a lithium-bearing rare-metal pegmatite intrusion that has penetrated along
the Kings Mountain shear zone, a regional structural feature known to host multiple lithium-bearing
pegmatites along its trend. The pegmatite field at Kings Mountain is approximately 1,500 feet(ft)wide
at its widest point in the historic pit area and narrows to approximately 400 to 500 ft in width at its
narrowest point south of the historic pit. The field has a lithium mineralization strike length of
approximately 7,500 ft and is predominantly contained in the mineral spodumene. The spodumene
pegmatite bodies exhibit a texture-based variation in lithium grade, spodumene grain size, mineral
alteration, and rock hardness.
After dewatering the historic pit, the lithium deposit is to be mined using conventional open pit mining
techniques. Blasting will fragment the ore and waste rock where it will be loaded and hauled to either
the processing facilities (ore)or the rock storage facilities (RSF) (overburden/waste rock). The current
plan includes mining in the existing pit and expanding the pit to the southwest. Ore would be drilled,
blasted, loaded, and transported by haul truck to a new processing plant at a rate of approximately
2.98 million tons (Mt) per annum of ore (-8,150 tons (t) per day)and processed to produce 385 to 440
thousand tons (kt) per annum of spodumene concentrate. The concentrate will be filtered to
approximately 11 percent (%) moisture by weight and transported off-site for further refinement into
lithium hydroxide monohydrate at a separate facility.
2.2.1 Archdale Tailings Facility
Tailings from the spodumene concentrate process at Kings Mountain will be filtered to approximately
10% to 15% moisture content by weight and transported off-site to the proposed Archdale facility for
disposal. The current Archdale site includes several shallow pit lakes formed from the previous mica
mining operations. These pit lakes will be dewatered and waste rock from the Kings Mountain pit will
be transported to Archdale for construction of the TSF embankment.
An initial TSF embankment(i.e., starter dam)will be constructed on-site to hold approximately 1 year
of filtered tailings. The filtered tailings material will be placed and compacted within a storage facility
with mobile equipment. Over the 10-year life of the Project, the TSF embankment will be raised, and
the filtered tailings will continue to be placed until the facility reaches its capacity. At final build-out the
TSF will contain 9.2 million short tons (Mst) of tailings, after which it will be closed and reclaimed.
Figure 2-2 presents the Project layout, showing the relative locations of the major components of the
Project. The Project is bounded by Interstate 85 on the southeast and Highway 24 on the northwest.
Access to the TSF will be off Highway 24 with a truck entrance and a light vehicle entrance. The site
will include minor office and maintenance facilities, parking, water storage facilities, and a TSF
perimeter access road.A small road base stockpile and growth media storage area are included in the
site plan.
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y
SrrE ENTRANCE -
FEET
100FT.PERIMETER r">'. _ --_'_—- — -_ - HIGH POINT
HAUL?ACCESS ROAD f ----------
FILTERED % r
TAILINGS '
STORAGE
LIGHT VEHICLE ENTRANCE ,•f � f`
r / ROCK I'LL,EMBANKMENTS
CREST 96D ELEV.amsE
/ SEEPAGE INTERCEPTION DRAIN
r /
PERIMETER ACCESS ROAD
WATER AND SEWER MAIN
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EXISTING CULVERTS[TYP.]
PROPOSED CULVERT(TYP-)
SEDIMENT BASINS
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i
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,
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PROPERTY BOUNDARY ///� -. OVERHEAD POWER
CONTACT WATER POND
GROWTH MEDIA /
STOCKPILE(-200k CY's) \ f / LAY DOWN AREA
TRUCK PARKING
PARKING
Source:SRK,2024b
Figure 2-2: Preliminary Site Layout
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2.3 Previous Mining
The Archdale TSF is located on a former mica mine. The following summary of the site is compiled
from records available to SRK:
• The site was formerly owned by the Kings Mountain Mica Company, which began operation in
1949.
• The site was owned by several different companies, including Franklin Minerals, Oglebay Norton,
Zemex, General Chemical, and Imerys between 1994 and 2021.
• Imerys expanded mining to a nearby property north of the Archdale site in 2011.
The presence of pit lakes at the Archdale TSF site since 2013 suggests that mining activities ceased
around that time. The current site layout encompasses several shallow pit lakes formed from the
previous mica mining operations. The property north of the Archdale site also contains a pit lake.
Figure 2-3 illustrates the site utilization based on satellite images dating back to 1999.
March 1999 Oerember 2005 March 20"
f_ r
December 2013 0—ber 2015 July 2023
1 r_Cr
r.
Source:SRK,2024b
Figure 2-3: Previous Usage of the TSF Area
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3 General Setting
3.1 Topography and Morphology
The Project area exhibits diverse topographic and geomorphological features reflecting the long and
dynamic history of geological and environmental processes. The landscape is primarily composed of
metamorphic rocks, such as biotite gneiss, amphibolite, and schist, which have been heavily
weathered and eroded over time.
The property north of the Archdale site and the Archdale site are positioned on opposite sides of the
topographic divide, with flows from the Archdale site directed to the south and flows at the site north
of the Archdale area flowing north. Topographic maps illustrate a gradient sloping southward in the
Archdale area. Elevations at the TSF area range from approximately 750 ft above mean sea level
(amsl)to over 1,050 ft amsl.
3.2 Surface Water Features
The Archdale site sits immediately south of a surface water divide roughly defined by South
Battleground Avenue. On the site, surface water drains south to an upper tributary of Dixon Branch
referred to as Archdale Creek. Dixon Branch joins with Kings Creek approximately 2 miles south of
the site in South Carolina(as shown on Figure 3-1). For the property north of the Archdale site,surface
water flows north into an unnamed tributary of Long Branch.
The site is heavily influenced by the legacy mining activities of the former mica mine. Existing
conditions result in local surface water collection in the open pits,which is pumped as part of operations
to an upper pond (shallow open pits)where it is allowed to flow through a rock filter dam before leaving
the property and flowing south under Highway 85 in a 60-inch-diameter concrete culvert. Additional
culverts crossing under Highway 85 are located at 500-to 800-ft intervals,with diameters ranging from
18 to 60 inches, discharging the drainage swale collecting runoff against the northern side of the
highway or drainages bypassing the legacy pits. These culverts typically discharge 20 to 35 ft below
the highway surface into Archdale Creek.
The site has no well-defined drainage due to legacy mining activities, but discharges from the Site
would flow into the Dixon Branch drainage, as shown in Figure 3-1. For the sake of clarity, this
document refers to the Unnamed Tributary (UT) of Dixon Branch that carries the discharges from the
Archdale property"Archdale Creek".
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raE N-E:Fig 2-1 WRgs Creek Watershed SRKPROJECTND._USPR*0000576
Source:SRK,2024b
Figure 3-1: Location of Kings Creek Watershed
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3.3 Project Climate
The Project is situated within the K6ppen-Geiger Cfa climate classification (Kottek, 2006), which
describes a continental type of climate without a dry season.Temperatures during the warmest months
are above 72 degrees Fahrenheit(°F), and temperatures in the coldest months are between 27°F and
65°F. Average monthly precipitation varies between 3 and 5 inches. Average annual precipitation is
42 inches, with an even distribution of rainfall throughout the year and an average annual snowfall of
4 inches. Southwestern North Carolina is prone to thunderstorms during the summer and ice storms
during the winter.
3.3.1 Temperature
The climate of the Project vicinity is humid subtropical with hot summers and mild winters.The monthly
temperature ranges from a minimum of around 3°F in January to a maximum of around 104°F in
August, with an average temperature of around 60°F. Historical data show that temperatures in the
area have been increasing, with an average rise of 0.3°F per decade since 1970, or roughly 1.7°F
from 1895 to 2020. Climate change is expected to further contribute to this warming trend, potentially
impacting surface water conditions, such as increased evaporation rates and altered streamflow
patterns. Predictive climate models suggest further warming in the future, potentially resulting in more
frequent and severe heatwaves and droughts.
3.3.2 Precipitation
Precipitation totals at the Project vary throughout the year. Based on the last 30 years, the area
typically receives between 41 to 55 inches of rainfall annually (Figure 3-2), with precipitation being
distributed relatively evenly throughout the year without a clear wet or dry season. The region is
susceptible to extreme precipitation events, such as tropical storms and hurricanes, which can bring
heavy rainfall and cause flooding.
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Distribution of Precipitation
80
70
v to —
L N
� 8 _
o
.a 5 40
a 30
20
o ¢`
10
a p
January February m—h April May June July Aug-t 5eptember October November December Annual Total
2.59G5% 5%-30% ■1D%-25% ■25%-SD% ■Median ■50%-75% ■75%-90% ■90%-95% 95%-97.5%
Annual Precipitation
ao
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r 60
c 50
Y 40
i 30
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1925 1930 1935 1940 1945 1950 1955 1%0 1%5 1970 1925 19 0 199i 1990 1195 2000 2005 2010 2015 2020
Source:SRK
Figure 3-2: Annual Precipitation and Distribution of Monthly Precipitation
3.3.3 Evaporation
Evaporation rates at the Project vary based on temperature, humidity levels, wind speed, and solar
radiation. Legacy data show that evaporation rates are highest in summer, averaging around 6 to
7 inches per month, and lowest in winter, with around 2 to 3 inches per month (Figure 3-3). Overall,
average annual evaporation ranges from 55 to 65 inches. Evaporation impacts surface water
availability by contributing to water loss from lakes, rivers, and streams. Factors, such as vegetation
cover, land use practices, and soil moisture levels, influence evaporation variability. Climate models
predict that evaporation rates will continue to increase in the future due to warming temperatures and
changes in precipitation patterns.
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S
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January February March April May June July August September October November December
Clemson Univ Chesnee 7 WSW Chapel Hill 2 W — — —Average Gold Sim
Figure 3-3: Average Monthly Evaporation
3.4 Regional Geology
The Kings Mountain District is located in the central part of the Piedmont Plateau. The plateau ranges
in elevation from 750 to 1,050 ft amsl. The rocks of the Piedmont Plateau are both igneous and
sedimentary in origin, with various grades of metamorphism observed. The meta-sedimentary rocks
include assemblages of gneissic and schistose rocks.
At the regional scale, metamorphism has modified sandstones to quartzites, impure or shaly
sandstones to graywackes and gneisses, shales to schists, and limestones to marbles. Some of the
sediments were in part volcanic in origin, such as volcanic ash or tuff laid down in water with varying
amounts of detrital material derived from weathering. The metamorphism of these rocks has produced
varieties of crystalline rocks transitional between those of purely sedimentary origin and those of purely
igneous origin.
Some of the regional-scale igneous protoliths underwent high-grade metamorphism and transformed
to mica and garnet gneisses or schists. The metamorphism made some of the meta-igneous rocks
indistinguishable from similarly foliated rocks of sedimentary origin. Other less-metamorphosed
igneous rocks in the area are generally classified as granite, diorite, gabbro, pyroxenite, peridotite,
porphyry, and diabase.These igneous rocks represent intrusive and extrusive events, such as granitic
batholiths (and associated pegmatite stock intrusions)and surface lava flows.
The understanding of the geological composition of the bedrock beneath the TSF is currently
undergoing further exploration and analysis. Legacy data collected from the site are not available, and
during the 2023 field program, drilling into bedrock was limited by equipment, ranging up to 30 ft in a
few cases. Observations from site reconnaissance suggest that the soil zone had previously been
removed from a majority of the site, exposing the saprolite. Based on the regional geologic maps, the
bedrock geology likely consists of muscovite schist and granite. Figure 3-4 shows the regional geology
around the TSF.
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. 5 _ Y '.; • r •1• ❑ M •^ �' : JUST OF MAP UNITS
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LEGEND USES.—II'+laa,2l)l:b
Name 9rk Consulting $.A.ceG• Y
©Archdale Tailings Facility +v..At:C �.�r-.VU A&ALBEMARLE �; Ea���A�Ae.EssME�taFuo.,
w:� ;2023 �e a¢N9121123 KINGS MOUNTAIN MINING PROJECT ARCHpALF TAIBN%S FACILITY
Fig 24
F�ax.acr-ar>or VSPRf10U570
Source: USGS,2006
Figure 3-4: Surface Geology
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3.5 Groundwater and Surface Water Quality
A total of 11 groundwater samples (including one duplicate and one field blank) and 6 surface water
samples (including one duplicate and one field blank) were collected from Archdale site during the
quarterly sampling event in December 2023. Monthly groundwater and surface water quality
monitoring has continued since this initial sampling. In addition, surface water samples were collected
from four locations in the Dixon Creek watershed located south of the TSF. Surface water locations
are shown in Figure 3-5: and groundwater locations are shown in Figure 3-6. A groundwater sample
was not collected from SNKM23-548 because the well was dry.Water quality samples were submitted
to ACZ Laboratories in Steamboat Springs, Colorado.
The groundwater in the Archdale area is mainly characterized by a neutral pH and sodium/potassium-
bicarbonate type geochemical signature. SNKM23-511 shows a different anion signature and is
characterized as a sodium/potassium-chloride type groundwater. SNKM23-540A shows a different
cation signature and is characterized as a mixed cation-bicarbonate type groundwater. There is no
apparent correlation between the major ion signature and the screened lithology.
Surface water samples at the Archdale site generally display a similar major ion geochemical signature
and are characterized as sodium/potassium-bicarbonate type waters. ADSW-3 shows a slightly
different major ion signature with mixed anions (i.e., bicarbonate/chloride). Surface water samples
from Dixon Branch are characterized as calcium+sodium-potassium/bicarbonate type waters.
Surface water and groundwater water quality data have been compared to the North Carolina
Department of Environmental Quality (NCDEQ) Surface Water Quality Standards for Class C Waters
and the North Carolina Groundwater Standards. Based on this assessment,the surface water samples
meet all surface water standards. The groundwater within the Archdale area does not meet the North
Carolina groundwater standard for iron and manganese. Total lead was the only other constituent
found above North Carolina groundwater standards and was only above the standard in one well
(SNKM23-531). However, the level of dissolved lead in SNKM23-531 was below the groundwater
standard. SNKM23-531 also exhibited the highest amount of Total Suspended Solids (TSS), which
could lead to higher total lead concentrations. The Dixon Branch water samples meet all groundwater
and surface water quality standards.
Radioactive elements (gross alpha and gross beta, radium-226/radium-228, and uranium) were
detected in most wells, but did not exceed North Carolina groundwater standards. The exception to
this I one well (SNKM23-531) with gross alpha levels elevated above North Carolina groundwater
standard. SNKM23-531 also contained the highest levels of gross beta, along with radium 226 and
228.
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SURFACE WATER SAMPLING LOCATIONS ra
2023 Surface Water V ADSW 1-20231211
Samples AD5W-2-20231211 1'
0 Dixon Creek Surface ADSW-"4-20231211 ADSW-3-2D232 11
Water Samples
Archdale Property
Boundary UT-Dixon-2D24D118
r f ♦�
_ 1 l
16
Y
1
s
US-D00n-2D2401 8
Confluence-2624- 8
DS-Dixon- D24D118•
0 300 600 900 12001500 w.,C
Feet
Figure 3-5: Archdale Surface Water Sample Locations
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r
5NKM 23-527-20331211
SHKM23=52 -2D231211
5NKM2 - 5 -20231 11
5NKM23-54D- 0231211
SNKM23-51 -2D231 11
a
SNKM23-557-2D2%-— b�
.SHKM23=550-20231 11
rt; 5HKM23-531-2D231 11
t
r,
SHKM23;! D231 11
GROUNDWATER SAMPLING LOCATIONS
Groundwater Samples
Archdale Property
Boundary
Figure 3-6: Archdale Groundwater Sample Locations
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4 Geochemical Characterization Summary
4.1 Future Tailings
Geochemical characterization of future tailings material that will be deposited at the Archdale site has
been completed as part of the Kings Mountain geochemical characterization program as described in
detail in the Kings Mountain Geochemical Characterization Report(SRK, 2024a).
Thirteen samples of flotation tails were submitted for geochemical testing to determine the bulk
geochemical characteristics and assess the potential to generate acid or release metals in drainage.
The ABA results indicate that overall, the sulfide sulfur content was low or below detection for the
flotation tailings. Neutralizing potential (NP) is also relatively low in the flotation tailings. The ABA and
NAG results demonstrate that the flotation tailings are depleted with respect to sulfide minerals,
demonstrating the effectiveness of sulfide removal in the ore sorting process. Flotation tailings that did
not undergo ore sorting have lower overall sulfide sulfur, indicating the magnetic separation process
also removes sulfides. The samples were classified as non-PAG based on ABA and NAG test results.
The two humidity cell tests (HCTs) representative of flotation tails have also maintained neutral
conditions throughout the test(Week 62 at the time of this report), as predicted by the static test data.
TSF porewater samples were obtained from lysimeters installed in the historical TSFs at Kings
Mountain. Lysimeter locations are provided in Figure 4-1 below and show the north lysimeter(KM23-
LY-01)was installed in the legacy TSF north of Highway 85 referred to as the Mill Tailings. The south
lysimeter(KM23-LY-02)was installed in the legacy TSF south of the highway referred to as the Chem
Tailings. The results for both lysimeters indicate the TSF porewaters are circum-neutral, which is
consistent with the static and kinetic test program. Metals concentrations are also low in the porewater,
with many parameters below analytical detection limits, including cadmium, beryllium, lead, chromium,
cobalt, boron, selenium, silver, and thorium. The results showed concentrations of a few parameters
that were higher in comparison to the leach test results for future tailings material including copper and
manganese.
Sulfate concentrations for the south lysimeter were higher than the north lysimeter, with a
concentration of 1,280 mg/L that is notably higher than seen for the north lysimeter (11.4 mg/L).
Furthermore, sulfate concentrations observed in the leach tests conducted on historic and future
tailings material have sulfate concentrations more comparable to the north lysimeter sulfate
concentrations. For these reasons, porewater from the north lysimeter is considered a better analog
for the future tailings.
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/ / �•
.. f rx
(CHEM TalI
' -- - APPROK ROHNCARY OF
LFG TAY IS) _
(MILL TAILINGS)
KM LY-02
G.
Figure 4-1: Legacy TSF Lysimeter Locations
4.2 TSF Embankment
Material that will be used for construction of the TSF embankment will be sourced from waste rock
mined from the King Mountain pit that is classified as non-potentially acid generating (non-PAG). The
site-specific approach for classifying waste rock as PAG or non-PAG is described in the Kings
Mountain Baseline Geochemical Characterization Report (SRK, 2024a).
Geochemical characterization of the non-PAG waste rock that may be sourced from Kings Mountain
has been completed as part of the Kings Mountain geochemical characterization program. This
involved the collection and analysis of 474 samples for static testing, with 22 representative samples
submitted for kinetic humidity cell testing.
The results of the static test work demonstrate that the Kings Mountain waste rock is variable with
respect to its acid generation potential. The amphibole gneiss schist is the main waste rock type and
demonstrates a low potential for acid generation and metal leaching. Other waste rock material types,
including the upper mica schist, biotite gneiss, mica schist, pyrrhotite mica schist, and shear schist,
are predicted to have net PAG potential, with average neutralization potential ratio (NPR) values of
less than 1 (<1). Only waste rock that is classified as non-PAG will be used in construction of the TSF
embankment.
Multi-element analysis indicated that several elements are enriched with respect to crustal averages
in the future waste rock materials, including arsenic, beryllium, cesium, lithium, rubidium, sulfur,
selenium,tin,thallium, uranium,and tungsten.Of these, modified SPLP testing(using deionized water)
indicated that arsenic, lithium, selenium, sulfur, and uranium would be leachable at detectable, albeit
low, dissolved concentrations.
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LEAF testing, a modernized suite of testing methods by the EPA, has extended the leach datasets to
a wider range of conditions (pH and liquid-to-solid contact ratios). Interpretation of the LEAF testing
indicates that the leach behavior of many trace elements is strongly controlled by pH-dependent
solubility and/or sorption processes. There is evidence, however, that for some elements (notably
lithium), a key control on leaching may be the presence of small, finite quantities of a soluble mineral.
In such cases, dissolved concentrations are strongly influenced by the L/S contact ratio.
4.3 Archdale Bedrock and Pit Wall Rock
Tailings generated from the Kings Mountain Mine will be placed directly into the Archdale Pit.
Geochemical characterization of bedrock and pit wall rock at Archdale has been undertaken as part of
the Archdale geochemical characterization program (SRK, 2024b). Nine bedrock samples considered
to be representative of pit wall rock were collected from eight drillholes,which were advanced to depths
between 30 and 120 ft bgs within the footprint of the Archdale site. The samples are representative of
Muscovite Pegmatite (seven samples) and Mica Schist (two samples) and were submitted for static
geochemical characterization testing.
The results can be summarized as follows:
• The Muscovite Pegmatite unit is characterized by sulfide sulfur contents below analytical detection
limits and has a low potential for acid generation (i.e., non-PAG)and metal leaching. Multi-element
analysis indicates that lithium, lead, selenium, tin, thallium, uranium, and tungsten are elevated
relative to average crustal abundance; however, out of these, only lithium, lead, and uranium were
detected in the SPLP leachate, demonstrating that these constituents may be leached from the
muscovite pegmatite pit wall rocks.
• The Mica Schist unit is characterized by higher sulfide sulfur content (0.81 to 1.0 wt%) in
comparison to the Muscovite Pegmatite. This material is classed as PAG based on NPR values
less than one. Multi-element analysis demonstrates similar enrichment as the Muscovite
Pegmatite samples with the exception of lithium and thallium that were notably lower in the two
Mica Schist samples compared to the Muscovite Pegmatite. Of these, only lithium, lead, and
uranium were detected in the SPLP leachate, demonstrating that these constituents could be
leached from the Mica Schist pit wall rock.
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4.4 Cover Material (Saprolite and Alluvium)
Saprolitic soils underlie the existing Archdale Pit and form the base of the TSF. Recompacted saprolitic
soils will also be used to line the inner face of the perimeter berm.
The outer slopes of the perimeter berm will be reclaimed as final grades are achieved. During closure,
the entire exterior TSF perimeter berm will be covered with a reclamation cover consisting of alluvium
and growth medium. The top of the tailings surface will also be graded to drain and covered with
reclamation cover.
Seven samples of alluvium and saprolite were collected from the holes drilled during the 2023 drilling
program and submitted for static geochemical characterization testing.The results can be summarized
as follows:
• The alluvium and saprolite materials have a low potential for acid generation, with sulfide sulfur
being close to the limit of detection for all samples.
• Multi-element analysis indicates that lithium, lead, selenium, tin, thallium, uranium, and tungsten
are elevated relative to average crustal abundance. Out of these elements, lithium, lead, and
uranium were the only elements readily detectable in the SPLP leachate of one sample of
saprolite.
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5 Kings Mountain Existing TSF Calibration Model
SRK has developed a calibration model for the existing historical Kings Mountain TSF. The calibration
model has been developed using static and kinetic geochemical characterization data from the Kings
Mountain characterization program, plus water quality monitoring data collected from the north
lysimeter installed in the legacy TSF at Kings Mountain located north of Highway 85. The purpose of
the calibration model is to develop parameter-specific scaling ratios that can be used to scale the
laboratory characterization data to field conditions for the existing Kings Mountain TSF. This approach
was then applied to predict future water quality for the Archdale TSF (described in Section 6).
The following data were used to develop the calibration model for the existing Kings Mountain TSF:
• SPLP1 and LEAF test data (EPA 1313) for samples of legacy tailings material collected from the
existing Kings Mountain TSF.
• Water quality results for samples collected from a suction lysimeter installed in the existing Kings
Mountain TSF that represents tailings pore water under steady state conditions.
• Groundwater chemistry from monitoring well SNKM22-432. This well is screened in the existing
Kings Mountain tailings and has broadly similar chemistry to the lysimeter.
The data review was limited to legacy tailings samples collected from the northern TSF as well as
water quality for the lysimeter and monitoring well installed in the northern TSF. The geochemical
signature for the tailings in the southern TSF is distinct from the northern tailings and is not considered
representative of future tailings.
Humidity cell test data are also available for two samples of tailings material and data are available
through week 62. The pH conditions for these two cells during the test have ranged from pH 6.5 to 7.7
(average pH 7.1). Based on the HCT results,the EPA 1313 data at pH 7 are expected to be analogous
to those in the existing historical TSF.
The lysimeter data were compared to the leachate data from the modified SPLP test and EPA 1313
test (at pH 7)to determine the degree to which the leach test results represent actual site conditions.
Based on this comparison the following conclusions were made:
• Parameters that are pH/redox controlled are generally higher for the lab data compared to the
lysimeter data (e.g., aluminum, arsenic, iron, manganese, sulfate).
• Parameters that are solubility controlled are generally lower for the lab data compared to the
lysimeter data (e.g., potassium, sodium, alkalinity).
• Some parameters are comparable for the lab and lysimeter data (e.g., pH, selenium, uranium).
Because some parameters are higher in the leach test data compared to the measured lysimeter data
and some parameters are lower, a uniform `upscaling'approach is not appropriate for scaling lab data
to field conditions. As an alternative approach, SRK developed a unique scaling factor for each
Note a modified version of the SPLP test with deionized water was used.
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parameter based on the relationship between modified SPLP/LEAF test data and the concentration in
the lysimeter.A parameter-specific ratio was calculated for each parameter by comparing the lysimeter
chemistry to the average of the modified SPLP chemistry and EPA 1313 chemistry at pH 7 for the
following five legacy tailings samples:
• B-SANDTAILINGS-002 (sand tailings collected from a depth of 0 to 0.5 feet)
• B389-003 B389-010 COMP (a composite sample of north tailings collected from a depth of 3 to
6.5 feet, and 21 to 27 feet)
• B434-005 (north tailings collected from a depth of 8 to 10 feet)
• B432-024 (black tailings collected from a depth of 48 to 55 feet)
• B434-022 (black tailings collected from a depth of 43 to 45 feet)
The resulting parameter specific scaling ratios were used to either 'upscale' or'downscale' the SPLP
and EPA 1313 results at pH 7 for the legacy tailings to develop a calibrated chemistry for the existing
TSF.
The lysimeter data do not include results for fluoride or chloride. As such, results from well SNKM22-
432 were used for these parameters. Similarly,the detection limit for mercury in the lysimeter data was
high and skewed the calibration. Therefore, the mercury result from well SNKM22-432 (that has a
lower detection limit)was used to develop the calibration model.
The calibrated tailings chemistry is provided in Table 5-1 and is the basis for the source term for the
future tailings material that was incorporated into the Archdale TSF model as described in Section 6.
The comparison of the lysimeter data and the calibrated chemistry in Table 5-1 shows a good
correlation between measured and predicted concentrations.Although originally considered,the LEAF
1313 data at pH 8 was not used, because a better calibration was obtained without it.
Comparison of the calibrated tailings chemistry to North Carolina groundwater standards, North
Carolina surface water standards shows that silver, copper and zinc are elevated above the surface
water standard. However, these exceedances can be attributed to laboratory detection limits in the
test work that are higher than the standards. Manganese is elevated above the groundwater standard
and is the only constituent elevated above an applicable standard in the calibrated tailings chemistry
that is not related to a laboratory detection limit constraint.
The parameter-specific scaling ratios developed as part of the calibration model were then applied to
the future Archdale TSF model. The full methodology is outlined in Section 6 below.
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Table 5-1: Kings Mountain Existing TSF Calibration Results
North Carolina North Carolina Average Lysimeter Calibrated
Parameter Units Surface Water Groundwater Data from Existing Tailings
Standard' Standard TSF (North) (n =2) Chemistry
pH S.U. 6.0-9.0 6.5-8.5 6.7 6.87
Alkalinity mg/L as CaCO3 >20** -- 36.1 39.2
Ag mg/L 0.00006 0.02t <0.0001 <0.0001
Al mg/L -- -- 0.05 0.01
As mg/L 0.15 0.01 t 0.001 0.001
B mg/L -- 0.7t 0.26 0.27
Ba mg/L -- 0.7t 0.089 0.092
Be mg/L 0.0065 -- <0.00008 0.00008
Ca mg/L -- -- 19.3 25.8
Cd mg/L 0.0097* 0.002t 0.00028 0.00035
CI mg/L 230 250 3.26** 3.32
Co mg/L -- -- 0.0009 0.0009
Cr mg/L -- 0.01 t 0.0007 0.0007
Cu mg/L 0.01266* 1 t 0.012 0.013
F mg/L 1.8 2 0.81** 0.82
Fe mg/L -- 0.3t 0.02 0.02
Hg mg/L 0.000012t 0.001 t 0.0000013*** 0.0000015
K mg/L -- -- 7.12 7.13
Li mg/L -- -- 0.42 0.56
Mg mg/L -- -- 2.7 4.07
Mn mg/L -- 0.05t 0.21 0.28
Mo mg/L -- -- 0.014 0.014
Na mg/L -- -- 20.1 20.1
Ni mg/L 0.07329* 0.1 t 0.0069 0.0093
P mg/L -- -- 0.25 0.25
Pb mg/L 0.0039* 0.015t 0.00014 0.00014
Sb mg/L -- 0.001 t 0.0008 0.0008
Se mg/L 0.0031§ 0.02t <0.0001 0.0001
Si mg/L -- -- 21.4 10
Sn mg/L -- -- <0.04 0.04
SO4 mg/L -- 250 11.4 19.6
Sr mg/L -- -- 0.46 0.63
TI mg/L -- 0.002t <0.0001 0.0001
U mg/L -- -- 0.0007 0.0007
V mg/L -- -- 0.086 0.086
Zn mg/L 0.16522* 1 t 0.098 0.25
NO3 mg/L as NO3 -- 44.3 -- 0.4
TDS mg/L -- 500 -- 104
-- Indicates no standard for parameter
0.01 Indicates predicted concentration is greater than most restrictive surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
' North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic
standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents
the 25th percentile of available data from Weir 7 and is a conservative approach to calculating a limit.
t Represents total recoverable metal concentration
**No results for Cl and F in lysimeter data.Uses data from well SNKM22-432 screened in existing tailings
***Detection limit for mercury in lysimeter data is too high.Uses data from well SNKM22-432 screened in existing tailings
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6 Archdale TSF Water Quality Predictions
6.1 Conceptual Model
A total of 9.2 million short tons (Mst) of flotation tailings from the spodumene concentrate process at
Kings Mountain will be filtered to approximately 10% to 15% moisture content by weight and
transported off-site to the Archdale TSF for disposal. The TSF will be built within the existing open pits
at Archdale and will have a surrounding embankment comprising approximately 4.37 Mst of newly
excavated non-PAG waste rock from the Kings Mountain site. The facility footprint will be
approximately 78 acres, comprising an internal tailings footprint of approximately 58 acres and a waste
rock embankment footprint of approximately 20 acres.
The filtered tailings material will be placed and compacted within the storage facility with mobile
equipment. Over the 10-year life of the Project, the TSF embankment will be raised, and the filtered
tailings will continue to be placed until the facility reaches its capacity. The facility will be closed once
it reaches full capacity and reclaimed.
Saprolitic soils underlie the existing Archdale Pit and form the base of the TSF. Recompacted saprolitic
soils will also be used to line the inner face of the perimeter berm. The embankment will be reclaimed
and covered with a reclamation cover consisting of alluvium and growth medium when final grades
are achieved. The top of the tailings surface will also be graded to drain and covered with reclamation
cover, which will reduce infiltration to the facility.
At the existing Archdale site, several pit lakes have formed in the formerly mined areas and the water
table is above the bottom of these existing pit lakes. Since the existing pit lakes at the Archdale facility
are likely in contact with the groundwater, any future tailings deposited in the pits will be in direct
contact with the groundwater system (SRK, 2024c). Prior to deposition of the tailings, the existing pit
lakes will be dewatered to provide a dry environment for the land preparation activities (i.e., sump
installation, earthwork). During operations, the groundwater entering the tailings will be removed by
the sump at the base of the facility and pumped to the contact water pond. At closure, the pumping
will cease, and groundwater will rebound within the tailings.
Conceptual models for the Archdale TSF have been developed for the operational and post-closure
periods and are shown in Figure 6-1 and Figure 6-2, respectively. The conceptual models have been
developed from the mine plan, groundwater model, water balance and ongoing geochemical
characterization program. Further details about the inputs and assumptions are provided in Sections
6.2 to 6.8.
The conceptual models developed for the Archdale TSF provide the basis for the development of the
water quality predictions. The general approach for modeling water quality for the facility is to quantify
annual solute concentrations in:
• Contact waters that will run off the tailings surface prior to cover placement and report to the
contact water pond. After cover placement, any runoff waters are assumed to only contact the
reclamation cover and will be non-contact water.
• Meteoric waters that will infiltrate the tailings and report to the drains at the base of the TSF and
be pumped to the contact water pond during operations.
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• Meteoric water that will enter the waste rock perimeter berm either through infiltration or as
groundwater flow.This water will either report to the drains at the base of the TSF and get pumped
to the contact water pond, or report as toe seepage to the seepage collection drain (SCD), also
referred to as the trench in design drawings.
• Groundwater underneath the facility (incorporates loading from both the tailings and surrounding
waste rock embankment).
• Water quality in the SCD adjacent to the TSF, which will receive toe seepage from the base of the
embankment (described above) and a proportion (approximately 90%) of seepage from the TSF
and embankment that reports to the shallow groundwater system and migrates to the SCD. The
remaining approximate 10% of seepage is assumed to bypass the SCD and report to Archdale
Creek. Note that this bypass travel through the low conductivity saprolite unit and is expected to
report over a long time span (SRK, 2024c).
• Water quality in the contact water pond (operations only), which will receive water from the SCD,
TSF sumps and from direct precipitation on the pond surface.
• Water quality in Archdale Creek. This is primarily assumed to be fed by base groundwater flow,
plus approximately 10%of seepage from the TSF and embankment that bypasses the SCD. Post-
closure, Archdale Creek will also receive flow directly from the SCD.
These water quality prediction points are shown on the conceptual model figures in Figure 6-1 and
Figure 6-2.
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Waste Rock Perimeter Filtered Tailings Interior Perimeter
Berm(20.5 acres) (57.7 acres) Berm
Direct precipitation JL
(5]
[9] Sump Pump to Contact
Water Pond(0) Net
Contact Precipitation(B)
Water Pond dump Pump to Contact
Water Pond(S)
(1]
Active Tailings Tailings Infiltration Op
WR Infiltration Op(E)
WR Infiltration Op(E) [1] Runoff(S) (C)
1
Tailings into Tailings Drainage
WR Loss to Toe Nj [ ] WR ,` 2[ ] -- - $APROLITE
Seepage <iJ Q ( ) to Drains(K) Z
Collection Seepage(R) 3
[ ] Tailings Loss to Regional Groundwater
Drain `:;:
Archdale g WR Drainage to 5 GW(N) Inflow(L)
Creek [ ] Drains(Z) [
Tailings Seepage WEATHERED BEDROCK
Returned from
Tailings Seepage to Groundwater(M)
[1f Regional WR Drainage 6roundwater(U) COMPETENT BEDROCK(<200 ft bgs)
Loss to GW
(o) KEY
[7] Water quality prediction point
Inflow
Outflow/Seepage/Uptake
Operational Period WR=Waste Rock
BEDROCKFrMPETENT 600 gs) Pr GW=Groundwater
Figure 6-1: Archdale TSF Conceptual Model -Operations
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Waste Rock Perimeter Filtered Tailings Interior Perimeter
Berm(20.5 acres) (57.7 acres) IL Berm
Net
Precipitation(B)
WR Infiltration
WR Infiltration Tailings Infiltration Closed(F)
Closed(F) Closed Tailings g
Runoff(T) Closed(D)
1 �-
Tailings into WR(G)Tailings Drainage [2]
Seepage WR loss to Toe [47 [3]� to Drains(K) 1
Collection Seepage(R) 1 Regional Groundwater SAPROLITE
Drain [6]� ... Tailings Loss to ( )
Archdale 7 WR Drainage rC GW(N) Inflow L
Creek r to Drains(z) � Tailings Seepage
I WEATHERED BEDROCK
Returned from
Tailings Seepage to Groundwater(M)
[10] 1 Regional COMPETENT BEDROCK(<200 ft bgs)
WR Drainage 1 Groundwater(U)
Loss to G W
(4) KEY
[7] Water quality prediction point
Inflow
Outflow/Seepage/Uptake
Closure Period WR=Waste Rock
GW=Groundwater
Figure 6-2: Archdale TSF Conceptual Model—Post-Closure
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6.2 Data Sources
The data sources for the Archdale TSF water quality predictions are summarized in Table 6-1. More
detailed information on each of these inputs is provided in the following sections.
Table 6-1: Archdale TSF Model Data Sources
Component Source Details
A water balance for the Archdale TSF has been
developed that provides details of monthly and annual
Water balance SRK(2024d) flows associated with the facility, including estimates of
infiltration, runoff, seepage, groundwater in/outflow and
flows to the contact water pond.
Tailings tonnages in TSF SRK(2024e) Tailings tonnages were obtained from the September
11, 2023 Mine Plan.
Volumes of non-PAG waste rock material in the TSF
Waste rock volumes and embankment were obtained from the waste rock
lithological composition SRK(2024f;g) production schedule. The volumes were converted to
in TSF embankment tonnages assuming a density of 120 pcf. It was
assumed the Iithological composition of the
embankment will be the same as RSF-A minus DMS .
Estimated emulsion usage was provided by Albemarle.
Emulsion usage Albemarle (2023) Estimated losses due to spills,failure to detonate and
residue from blast detonation are assumed to be 3%.
Representative rainwater chemistry data from monthly
Precipitation chemistry NADP(2022) monitoring carried out between 2011 and 2021 at the
Piedmont Research Station Meteorological Station,
North Carolina.
Scaled SPLP' and LEAF test data from the SRK
SRK Geochemical geochemical characterization program have been used
Tailings chemistry Characterization to develop source terms for the tailings in the TSF.The
Program (SRK, data were scaled to field conditions based on
2024a) parameter-specific scaling factors developed as part of
the existing TSF calibration model.
Scaled HCT data from the SRK HCT program have
SRK Geochemical been used to develop source terms for the non-PAG
Waste rock embankment Characterization waste rock in the embankment. The data were scaled
chemistry Program (SRK, to field conditions based on the difference in
2024a) temperature and liquid to solid ratio between the lab
HCT and field conditions.
Representative groundwater chemistry data in the
Groundwater chemistry SRK(2024b) vicinity of the TSF were obtained from samples
collected by SRK as part of the Archdale field and
drilling campai n in December 2023.
Note a modified version of the SPLP test with deionized water was used.
6.3 TSF Composition
The mass of tailings that will report to the TSF was obtained from the ore production schedule in the
September 11, 2023 mine plan, which states that 9.2 Mst of tailings will be produced over LOM, with
an annual production rate of approximately 1.1 Mst (SRK, 2024e).
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6.4 Waste Rock Embankment Composition
The volume of waste rock that will be used in construction of the Archdale TSF embankment was
obtained from the waste rock production schedule (SRK, 2024f), which states that 2,700,009 cubic
yards of material will be used. This was converted to a mass of 4.37 Mst using an assumed density of
120 pcf.
It is assumed the embankment will comprise entirely freshly mined non-PAG material from the Kings
Mountain site. The lithological composition of the embankment is listed in Table 6-2 and is assumed
to be the same as the waste rock component of RSF-A(SRK, 2024g)with the exception that no Dense
Media Separation (DMS) rejects will be placed in the TSF embankment.
Table 6-2: TSF Embankment Tonnage and Lithological Composition
Mass in TSF Proportion in TSF
Non-PAG Unit Embankment Embankment
Mst
Amphibole Gneiss-Schist 0 0%
Chlorite Schist 0 0%
Mica Schist 1.57 35.8%
Muscovite Peg 0.01 0.3%
Overburden 0.74 16.8%
Pegmatite 0.008 0.2%
Schist-Marble 0.04 0.9%
Shear Schist 0.92 21.0%
Silica Mica Schist 1.00 23.0%
Spodumene Peg 0 0%
Upper Mica Schist 0.09 2.0%
Po Mica Schist 0.003 0.1%
Total 4.37 100%
6.5 Water Balance
A water balance for the Archdale TSF has been developed by SRK including estimates of infiltration,
runoff, seepage, groundwater in/outflow and flows to the contact water pond (SRK, 2024d;h). Each of
the flow components included in the water balance are labelled as A to Z on the conceptual models
shown in Figure 6-1 and Figure 6-2. Average flows for each of these components during the
operational and post-closure periods are listed in Table 6-3. Full details of how the water balance was
developed are provided in SRK (2024h)and the main points pertinent to the water quality predictions
are summarized below.
According to the groundwater flow model and water balance (SRK, 2024c;h), groundwater will flow
into the TSF during the operational and post-closure phases and will contact the tailings and adjacent
waste rock embankment. During the operational phase, the facility will be drained by sumps located
under the TSF and this flow will report to the contact water pond. These drains will be deactivated
during the recovery phase and the groundwater will be allowed to recover(SRK, 2024c).
Groundwater flowing into the TSF and adjacent embankment will originate from the saprolite and
weathered bedrock underlying the facility. During operations, approximately 23% of groundwater flow
into the TSF is estimated to originate from saprolite and 77% will originate from weathered bedrock.
Post-closure, groundwater flows are estimated to be approximately 60% and 40% from the saprolite
and weathered bedrock units, respectively.
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In addition to groundwater entering the facility,a proportion of precipitation falling on the facility surface
will infiltrate the tailings and adjacent waste rock embankment. During operations, infiltration to the
tailings is assumed to be 40% of mean annual precipitation (MAP), with approximately 65% of MAP
assumed to infiltrate the waste rock embankment. At closure, infiltration to both the TSF and
embankment will reduce to approximately 3% of MAP as a result of the cover application.
During operations, water that infiltrates the facility will either report to the sumps at the base of the
facility, report as toe seepage at the toe of the embankment, report to the SCD adjacent to the facility
or recharge groundwater. Post-closure the sumps will no longer be operational, and this water will
either report as toe seepage from the embankment, report to the SCD adjacent to the facility or
recharge groundwater. Groundwater flow underlying the TSF is assumed to be approximately
102 gpm.
Surface water running off the side of the TSF, toe seepage from the waste rock embankment and
shallow groundwater and will be collected in a SCD (SRK, 2024c). The SCD will also receive a
proportion (approximately 90%)of seepage from the TSF and embankment that reports to the shallow
groundwater system and migrates to the SCD. During operations, water from the SCD will be fed to
the contact water pond along with water from the TSF sumps. Post-closure, the contact water pond
will no longer be operational and water from the SCD will report directly to Archdale Creek.
Archdale Creek is primarily assumed to be fed by base groundwater flow, plus approximately 10% of
seepage from the TSF and waste rock embankment that bypasses the SCD. Post-closure, Archdale
Creek will also receive flow directly from the SCD.
Table 6-3: Average Flows During the Operational and Post-Closure Periods
Average During Average Post-
Component Operations Closure
pm pm
Tailings Uncovered Infiltration (C) 55.9 0
Tailings Covered Infiltration (D) 0 4.62
Waste Rock Uncovered Infiltration E 8.66 0
Waste Rock Covered Infiltration F 0.98 1.64
Tailings Water to Waste Rock Berm (G) 8.29 0.42
Tailings Seepage to Collection Drains(K) 95.8 7.06
Regional Groundwater inflow to TSF (L) 117 28.3
Tailings Groundwater Seepage return to TSF (M) 30.7 2.62
Tailings Seepage to Shallow Groundwater(N) 30.7 2.62
TSF Sump Pumping to Pond (0) 188 2.52
Waste Rock Seepage to GW(Q) 64.4 7.08
Waste Rock Toe Seepage(R) 0.41 2.21
Active tailings runoff/Pump to Pond (S) 2.27 0
Closure Runoff to Perimeter(T) 0 8.43
Tailings Seepage to Regional Groundwater U 26.2 2.50
Waste Rock Drainage to Drains Z 13.5 2.06
Runoff from the exterior berm of the TSF (A) 3.47 2.99
Contact Pond Direct Precipitation 3.40 0.10
Regional Groundwater Flow 102 102
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6.6 Chemistry Inputs
6.6.1 Precipitation Chemistry
The primary source of water to contact material within the Archdale TSF and embankment is assumed
to be precipitation. In the absence of any site-specific precipitation chemistry data, the chemistry of
representative rainwater was obtained from monthly monitoring carried out between 1978 and 2021 at
the Piedmont Research Station, Rowan County, North Carolina (NADP, 2022), which is located
approximately 85 km from the Project area.
Precipitation chemistry at the Piedmont Research Station has been variable over the period of record,
with increasing pH trends and decreasing trends in sodium, chloride, calcium, magnesium, sulfate and
nitrate overtime (Figure 6-3 to Figure 6-5). As such, data from the last 10 years (2011 to 2021) have
been used in the water quality predictions (Table 6-4).
Table 6-4: Piedmont Research Station Precipitation Data -2011 to 2021
Parameter Units Value
pH S.u. 5.29
Ca mg/L 0.06
CI mg/L 0.17
K mg/L 0.05
Mg mg/L 0.02
Na mg/L 0.10
SO4 mg/L 0.47
NH4 mg/L 0.31
NO3 mg/L 0.55
Source: NADP,2022
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6
5
4
R
42. 3
x
a a i
Period used in
2 water quality
predictions
1
0
1985 1995 2005 2015 2025
Figure 6-3: pH Trends at Piedmont Research Station (NADP, 2022)
3.5
3
Period used in
water quality
2.5 predictions
J
OA 2
E
41
.� 1.5
3
N
1
0.5 —
0 �i
1975 1985 1995 2005 2015 2025
Figure 6-4: Sulfate Trends at Piedmont Research Station (NADP, 2022)
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0.45
0.4
Period used in
0.35 water quality
predictions
0.3
J
OQ
E 0.25
a�
L 0.2
0
s
u 0.15
0.1
0.05
0
1975 1985 1995 2005 2015 2025
Source:NADR 2022
Figure 6-5: Chloride Trends at Piedmont Research Station
6.6.2 Tailings Chemistry
Representative leachate chemistry data for the future tailings material was obtained from modified
SPLP testing (using deionized water) and EPA 1313 testing carried out on two composite samples
(COMP1 and COMP2) obtained from the 2023 Met Program. The EPA 1313 test results at pH 7 were
used, as these are the most representative of the pH conditions expected in the future TSF based on
the HCT program and is a conservative approach. The results were scaled to field conditions using
the parameter-specific calibration factors developed as part of the Kings Mountain existing TSF
calibration model (Section 5). The scaled tailings source term used as input to the water quality
predictions is provided in Table 6-5.
Table 6-5: Tailings Source Term used in Archdale TSF Model (Scaled to Field Conditions)
Tailings
Parameter Units Source
Term
pH S.U. 8.20
Alkalinity mg/L as CaCO3 324
Ag mg/L 0.0001
Al mg/L 0.10
As mg/L 0.002
B mg/L 0.27
Ba mg/L 0.08
Be mg/L 0.00005
Ca mg/L 58.1
Cd mg/L 0.0002
CI mg/L 7.06
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Tailings
Parameter Units Source
Term
Co mg/L 0.0008
Cr mg/L 0.0007
Cu mg/L 0.0087
F mg/L 0.36
Fe mg/L 0.01
Hg mg/L 0.0000009
K mg/L 2.06
Li mg/L 0.38
Mg mg/L 1.68
Mn mg/L 0.005
MO mg/L 0.01
Na mg/L 19.4
Ni mg/L 0.005
P mg/L 1.49
Pb mg/L 0.0001
Sb mg/L 0.003
Se mg/L 0.00009
Si mg/L 11.8
Sn mg/L 0.04
SO4 mg/L 3.80
Sr mg/L 1.09
TI mg/L 0.00004
U mg/L 0.0017
V mg/L 0.086
Zn mg/L 0.06
NO3 mg/L as NO3 26.3
6.6.3 Waste Rock Embankment Chemistry
Source terms for the non-PAG waste rock in the TSF embankment were developed from the results
of the ongoing HCT program that were scaled to field conditions. The HCTs used to represent non-
PAG waste rock are listed in Table 6-6 along with relevant static and kinetic test data. The HCT
program is currently ongoing, and data collected up to week 74 were used in the source term
development.
The unscaled source term chemistry for the non-PAG waste rock is listed in Table 6-7. The method
for scaling the HCT chemistry to field conditions is consistent with that used for waste rock in RSF-A,
RSF-X and RSF-W (SRK, 2024g) and is described below.
6.6.4 Derivation of Rock Weathering and Leaching Rates for Embankment
A scaling factor was applied to the laboratory HCT data to account for the differences in reaction
masses, reaction rates, temperature and liquid-to-solid ratios between the laboratory test and field
conditions. Site-specific scaling factors were developed based on information relating to the water
balance, geological model and mine plan.
The Archdale TSF model assumes that a fraction of the total mass within the embankment will be
effectively contacted by meteoric waters reflecting the coarse nature of waste rock, preferred flow
paths and high field capacity. This fraction is termed the'contacted mass'or the'reactive mass',which
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is a result of the combined influence of wetting and grain size effects on small particles and the surface
of particles, whereby a proportion of the total mass will be effectively isolated within larger particles
and therefore unavailable for contact with water, weathering, and mobilization of constituents. The
assumptions regarding the derivation of the contacted mass are described below.
Future waste rock at Kings Mountain is expected to be relatively coarse in terms of grain size
distribution. It is assumed that any water infiltrating the embankment will only contact the outermost
150 pm of each individual waste particle (i.e., a reactive rim, see Figure 6-6). The contacted mass (P)
of material within the embankment was determined by establishing the relationship between the
volume/mass in the outermost reactive rim and the total volume/mass of each particle. Based on an
assumed reactive rim of 150 pm and the waste rock particle size distribution (PSD) data presented in
SRK(2024g), approximately 2.1% of the total mass of waste rock within the embankment is assumed
to be contacted by meteoric waters and contribute to solute loading during operations. The leaching
rates from the HCTs were then applied to this mass to define source term chemistry as described in
Equation [2] and Equation [3]. Once the embankment is covered and reclaimed, the mass of material
that will be contacted by meteoric water is assumed to reduce in-line with the reduction in infiltration.
150 µm
reactive rim
r�
' �5t
Particle
diameter
0
5
Figure 6-6: Cross-section Showing Reactive Rim of Waste Rock Particle
In addition to wetting and grain size effects within the embankment, the ambient temperature in the
field will also affect reaction rates and solute release. Therefore, an additional scaling factor has been
applied that considers the difference in temperature between the laboratory HCT (conducted at 250C
according to ASTM 5744-13e1)and annual average field conditions in the Project area(15.21C)2.This
2 Average temperature data were derived from Shelby, approximately 22.5 km from Kings Mountain. Data for
the period 1937 to 2018 were evaluated.
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scaling factor was developed from the calculated difference in rate constant, as determined from the
Arrhenius equation in Equation 1.
EA
Equation 1 K = Ae-RT
Where:
K= rate constant
A = frequency factor(assumed to be approximately constant)
EA = Activation energy (assumed to be 88,000 joules per mole (J/mol) (Nicholson et al.,
1988)
R = Gas constant(8.31 joules per mole per kelvin [J/mol/K])
T= Temperature (kelvin)
Rate constants(K)are developed for both laboratory temperature conditions(Kiab)and annual average
field temperature conditions (Kfieia) and the temperature scaling factor (T) is defined as Kfleld/Klab. As
with the laboratory HCTs, the embankment is assumed to be fully oxygenated and therefore no
additional oxygen scaling factor has been applied. This is a conservative assumption.
The HCT chemistry data were then scaled using Equation
Equation 2 C•i = R;xMxPxTxO
21
Where:
Ci= scaled dissolved concentration of element i (mg/L)
Ri= average release rate of element i in the HCTs (mg/kg/week)
M= total mass of material in embankment(kg)
P= proportion of material contacted by infiltration to the facility(%), assumed to be 2.1%
T= temperature scaling factor based on Arrhenius equation (unitless)
O= oxygen scaling factor (unitless), assumed to be 1 for this analysis (i.e. no oxygen
scaling factor applied)
Qi= average infiltration from the water balance (L/week)
Using this approach, seepage source terms were developed for each non-PAG lithology within the
embankment. These source terms were then mixed according to the relative proportion of each
lithology to develop a combined source term for the embankment using the methodology outlined in
Equation 3.
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Equation 3 Essr = (CiA x LiA)+ (CiB x LiB) + (Cic x Lic)...etc
Where:
Essr= embankment seepage source term
CiA= scaled dissolved concentration of element i for lithology A (mg/L)
LiA = proportion of lithology A in embankment, etc.
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Table 6-6: Humidity Cells used to Develop Source Terms for Non-PAG Waste Rock in TSF Embankment
Mica Muscovite Schist- Shear Silica Mica Upper Po Mica
Schist Pegmatite Overburden Pegmatite Marble Schist Schist Mica Schist
Schist
HCTs used in Source Term HCT-14 HCT-21 HCT-01 HCT-21 HCT-26 HCT-18 HCT-26 HCT-03 HCT-14
Development
Hole/Sample ID DDKM17- DDKM17- DDKM17- DDKM17- DDKM18- DDKM18- DDKM18- DDKM17- DDKM17-
019 037 121 037 317 206 317 080 019
From (ft) 1289.22 1381.27 0 1381.27 189 845.8 189 842.5 1289.22
To(ft) 1292 1384.71 16.4 1384.71 194 850.75 194 846.94 1292
Sulfide S (wt%) 0.04 0.005 0.005 0.005 0.05 0.26 0.05 0.03 0.04
N N P (kg CaCO3 eq/t 7.8 2.85 0.35 2.85 16.4 27.9 16.4 5.1 7.8
NPR 7.5 20 1 3.33 20 11.3 4.44 11.3 6.67 7.5
Acid Generation Prediction Uncertain Uncertain Uncertain Uncertain Uncertain Non-PAG Uncertain Uncertain Uncertain
based on ABA
NAG pH (s.u.) 7.2 6 5 6 7.4 10.4 7.4 5.8 7.2
NAG (kg H2SO4 eq/t 0.5 10 2 10 0.5 0.5 0.5 4 0.5
Acid Generation Prediction Non-PAG Non-PAG Non-PAG Non-PAG Non-PAG Non-PAG Non-PAG Non-PAG Non-PAG
based on NAG
Current HCT status (weeks) 73 73 74 73 66 73 66 74 73
Current HCT pH s.u. 5.8 5.9 4.8 5.9 6.3 6.2 6.3 5.5 5.8
Final Classification I Non-PAG I Non-PAG I Non-PAG I Non-PAG I Non-PAG I Non-PAG I Non-PAG I Non-PAG I Non-PAG
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Table 6-7: Non-PAG Waste Rock HCT Source Terms used in Archdale TSF Model (Unscaled)
Mica Muscovite Schist- Shear Silica Upper Po Mica
Parameter Units Schist Peg Overburden Pegmatite Marble Schist Mica Mica Schist
Schist Schist
HCT-14 HCT-21 HCT-01 HCT-21 HCT-26 HCT-18 HCT-26 HCT-03 HCT-14
H S.U. 6.34 6.16 4.80 6.16 6.94 6.83 6.94 5.70 6.34
-Alkalinity mg/kg/week as CaCO3 8.64 3.91 1.37 3.91 6.92 14.63 6.92 3.31 8.64
-Ag m /k /week - - - - - - - - -
AI mg/kg/week 0.13 0.05 - 0.05 0.08 0.12 0.08 0.06 0.13
As mg/kg/week 0.0022 0.0012 - 0.0012 0.0036 - 0.0036 0.0002 0.0022
B mg/kg/week - - 0.013 - - - - - -
Ba -mg/kg/week - - - - - - - - -
Be mg/kg/week 0.00004 - - - - - - - 0.00004
Ca mg/kg/week 3.64 0.26 0.05 0.26 3.42 8.81 3.42 2.84 3.64
Cd mg/kg/week - - - - - - - - -
CI I mg/kg/week 0.47 0.50 1.02 0.50 0.47 0.53 0.47 - 0.47
Co mg/kg/week - - - - - - - - -
Cr -mg/kg/week - - - - - - - - -
Cu mg/kg/week - 0.005 - 0.005 - - - - -
F mg/kg/week 0.14 0.07 - 0.07 - 0.09 - 0.08 0.14
Fe mg/kg/week - - - - - - - - -
_Hg mg/kg/week 0.0000003 0.0000003 0.0000003 0.0000003 0.0000002 0.0000002 0.0000002 - 0.0000003
K mg/kg/week 0.92 0.16 0.13 0.16 1.17 1.20 1.17 0.44 0.92
Li mg/kg/week 0.22 0.76 0.008 0.76 0.08 0.42 0.08 0.04 0.22
-Mg mg/kg/week 0.16 0.09 0.09 0.09 0.49 0.90 0.49 0.13 0.16
Mn mg/kg/week - 0.010 0.005 0.010 - 0.016 - - -
Mo mg/kg/week - - - - - - - - -
Na -mg/kg/week 0.91 0.77 0.81 0.77 0.36 1.32 0.36 0.46 0.91
Ni mg/kg/week - - - - - - - 0.004 -
P mg/kg/week - 0.88 - 0.88 - - - - -
Pb mg/kg/week 0.00005 0.00006 0.00004 0.00006 - - - - 0.00005
Sb mg/kg/week 0.00034 0.00038 - 0.00038 0.00098 0.00030 0.00098 0.00040 0.00034
Se mg/kg/week 0.00009 - 0.00011 - 0.00008 0.00022 0.00008 0.00007 0.00009
Si mg/kg/week 0.62 0.55 1.18 0.55 0.85 0.73 0.85 0.51 0.62
Sn -mg/kg/week - - - - - - - - -
SO4 mg/kg/week 1.90 0.63 0.82 0.63 5.64 15.86 5.64 4.41 1.90
Sr mg/kg/week 0.011 - - - 0.005 0.013 0.005 0.005 0.011
TI mg/kg/week - - - - - 0.00007 - - -
U mg/kg/week 0.0004 0.0007 0.0007 0.0001 0.0001 0.0001 0.0003 0.0004
V mg/kg/week - - - - - - - - -
Zn mg/kg/week
- - - - - - - - -
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6.6.5 Groundwater Chemistry
Representative groundwater chemistry in the vicinity of the Archdale TSF was obtained from samples
collected by SRK as part of the Archdale field and drilling campaign in December 2023. The wells are
screened in a combination of saprolite and weathered bedrock. The groundwater chemistry for each
of these units is listed in Table 6-8. For the purpose of the water quality predictions the chemistry of
the saprolite and weathered bedrock groundwater was proportioned according to the flow from each
of these units into the TSF (see Section 6.5).
Table 6-8: Groundwater Chemistry used in Archdale TSF Model
Saprolite Weathered Bedrock
Average of wells SNKM23-
Parameter Units Average of wells SNKM23- 511, SNKM23-527,
531A and SNKM23-553 SNKM23-529, SNKM23-
540A, SNKM23-550 and
SNKM23-557
pH units 7.48 7.34
Alkalinity mg/L as CaCO3 29.8 30.5
Ag mg/L <0.0001 0.0001
Al mg/L 0.02 0.15
As mg/L 0.0003 0.0003
B mg/L <0.03 <0.03
Ba mg/L 0.013 0.016
Be mg/L 0.00064 0.00034
Ca mg/L 2.85 5.47
Cd mg/L 0.00028 0.00029
CI mg/L 5.11 8.72
Co mg/L 0.002 0.004
Cr mg/L 0.0005 0.0006
Cu mg/L <0.0008 0.0009
F mg/L <0.15 0.19
Fe mg/L 1.56 1.06
Hg mg/L 0.0000008 0.0000010
K mg/L 2.70 2.97
Li mg/L 0.05 0.07
Mg mg/L 1.04 1.73
Mn mg/L 0.84 0.84
Mo mg/L 0.002 0.001
Na mg/L 7.91 9.30
Ni mg/L 0.002 0.002
P mg/L <0.1 0.10
Pb mg/L <0.0001 0.0003
Sb mg/L <0.0004 <0.0004
Se mg/L <0.0001 <0.0001
Si mg/L 8.92 10.9
Sn mg/L <0.04 <0.04
SO4 mg/L <1 3.78
Sr mg/L 0.01 0.03
TI mg/L 0.0005 0.0003
U mg/L 0.0008 0.002
V mg/L <0.0005 0.0007
Zn mg/L 0.030 0.011
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6.7 Nitrate Leaching from TSF Embankment
The use of blasting emulsion during mining at Kings Mountain will potentially lead to leaching of
explosive residues (primarily nitrate)from the TSF waste rock embankment. Potential nitrate leaching
rates cannot be derived from the HCT program,as this testwork is conducted on mechanically crushed
core material rather than blasted rock.Therefore,the amount of nitrate that may potentially be leached
from the waste rock within the embankment has been calculated from information regarding estimated
explosive usage at Kings Mountain, in addition to estimates of seepage from the water balance.
Emulsion tonnages were obtained from Albemarle, approximately 0.3 kg of emulsion will be consumed
per ton of rock (i.e., powder factor), with approximately 1.5% of this mass being lost due to spillage
during loading blast holes and 1.5% of this mass being lost to occasional misfired holes, giving a total
loss of 3% (Albemarle, 2023c). Due to the highly soluble nature of nitrogen compounds, it is assumed
that any explosive residue that is accessible will be leached within a year of emplacement and that
any nitrate leaching is therefore attributed to waste rock deposited during the previous year.
6.8 Equilibration Sensitivity Analysis
The base case water quality predictions described above use a mass balanced approach, whereby
the tailings, waste rock and groundwater source terms are mixed in the proportions provided in the
water balance to provide a mass balanced chemistry at the various water quality prediction points.
This is considered a conservative approach, as mineral precipitation and trace element sorption
processes (i.e., natural processes that may remove trace elements from solution and will likely occur)
are not accounted for.
A sensitivity analysis has been undertaken to evaluate the effect of incorporating mineral equilibration
and sorption on the resulting water chemistry. This sensitivity was undertaken using the USGS
program PHREEQC (Parkhurst and Appelo, 1999)for the following key prediction points:
• Groundwater underneath the facility (point [7] in Figure 6-1 and Figure 6-2).
• The contact water pond (point [9] in Figure 6-1).
• Archdale Creek (point [10] in Figure 6-1 and Figure 6-2).
The mineral phases included in the model are listed in Table 6-9 and are consistent with those used
in the Kings Mountain RSF water quality predictions.These mineral phases are considered appropriate
given the geology and mineralogy of the mine materials.
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Table 6-9: Mineral Equilibrium Phases used in the Equilibration Sensitivity Analysis
Mineral Ideal Formula
Equilibrium Phase
Alunite KAI3(SO4)2(OH)6
Barite BaSO4
Birnessite MnO2
Calcite CaCO3
Cerussite PbCO3
Ferrihydrite Fe(OH)3
Fluorite CaF2
Gibbsite AI(OH)3
Gypsum CaSO4.2H2O
Malachite Cu2(OH)2CO3
MnHPO4 MnHPO4
Pyromorphite Pb5(PO4)3CI
Rhodochrosite MnCO3
SbO2 SbO2
Tenorite CuO
6.9 Model Results
6.9.1 Base Case
Predicted water quality in the contact water pond, Archdale Creek and groundwater underneath the
TSF is summarized in Table 6-10 to Table 6-12 for the operational and post-closure periods. The
annual predicted water quality for all of the 10 prediction points labelled in Figure 6-1 and Figure 6-2
is presented in full in Appendix A.
Predicted water quality has been compared against NCDEQ Surface Water Quality Standards for
Class C Waters and North Carolina Groundwater Quality Standards. In addition, predicted
groundwater quality underneath the TSF has been compared to existing groundwater quality, and
predicted water quality in Archdale Creek has been compared to existing surface water quality at US
Dixon and UT Dixon sample locations.
The results show that predicted water quality in the contact water pond, Archdale Creek and
groundwater underneath the facility is circum-neutral (pH 6.7 to 7.4), with all parameters predicted to
be below North Carolina Surface Water Standards. The majority of parameters are also predicted to
be below North Carolina Groundwater Quality Standards. The only exceptions are iron and
manganese, which are elevated in existing (i.e., baseline) groundwater at Archdale. Antimony in the
contact water pond and Archdale Creek is predicted to be marginally above the North Carolina
Groundwater Quality Standard of 0.001 mg/L during the operational period, with predicted
concentrations between 0.0011 mg/L and 0.0018 mg/L. However, it is noted that groundwater
standards are not applicable to the contact water pond and Archdale Creek and a comparison is
presented for completeness only. In addition, the site-specific saprolitic soils and shallow aquifer are
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expected to provide natural attenuation in the form of oxide sorption sites further reducing
concentrations of this parameter of interest. Post-closure, the contact water pond will no longer be
operational. Antimony concentrations in groundwater underneath the TSF are predicted to be below
the North Carolina Groundwater Quality Standard for both the operational and post-closure periods.
6.9.2 Equilibration Sensitivity Analysis
The results of the equilibration sensitivity analysis are summarized in Table 6-13 to Table 6-15. The
results show that the equilibrated chemistry is similar to the mass balanced chemistry, however
predicted concentrations of iron, manganese and aluminum are slightly lower for the equilibrated
chemistry sensitivity, reflecting the precipitation of ferrihydrite, alunite, and MnHPO4. In addition,
predicted antimony concentrations are slightly lower for the equilibration sensitivity analysis, reflecting
a combination of SbO2 precipitation and adsorption onto precipitated iron oxides. However, average
and maximum antimony concentrations in the contact water pond, and maximum antimony
concentrations in Archdale Creek are still predicted to be above the North Carolina groundwater
standard during operations. Although groundwater standards are not applicable to the contact water
pond and Archdale Creek, a comparison has been presented for completeness.
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Table 6-10: Predicted Groundwater Quality Underlying the Archdale TSF (Base Case)
Existing Weathered
North North Existing Saprolite Bedrock Groundwater Predicted Groundwater Quality During Predicted Groundwater Quality Post-
Carolina Carolina Groundwater Quality Quality(average of wells Operations Closure
Parameter Units Surface Groundwater (average of wells SNKM23-511, SNKM23-
Water 1 Standard SNKM23-531A and 527, SNKM23-529,
Standard SNKM23-553) SNKM23-540A, SNKM23- Average Minimum Maximum Average Minimum Maximum
550 and SNKM23-557)
H SM. 6.0-9.0 6.5-8.5 7.48 7.34 7.02 6.75 7.24 7.27 7.26 7.29
-Alkalinity m /L as CaCO3 >20** -- 29.8 30.5 51.3 32.0 60.7 31.9 31.3 32.1
-Ag m /L 0.00006 0.02t <0.0001 0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
AI m /L -- -- 0.02 0.15 0.16 0.13 0.22 0.08 0.08 0.08
As m /L 0.15 0.01 t 0.0003 0.0003 0.001 0.0005 0.002 0.0005 0.0005 0.0005
B m /L -- 0.7t <0.03 <0.03 0.05 0.03 0.05 0.03 0.03 0.03
Ba m /L -- 0.7t 0.013 0.016 0.019 0.015 0.022 0.014 0.014 0.015
Be m /L 0.0065 -- 0.00064 0.00034 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005
Ca m /L -- -- 2.85 5.47 9.70 5.41 12.1 4.50 4.35 4.55
Cd m /L 0.00097* 0.002t 0.00028 0.00029 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
-Cl m /L 230 250 5.11 8.72 8.34 7.92 8.55 6.60 6.59 6.61
Co m /L -- -- 0.002 0.004 0.0038 0.0036 0.0038 0.0028 0.0028 0.0028
Cr m /L -- 0.01 t 0.0005 0.0006 0.0006 0.0006 0.0007 0.0006 0.0006 0.0006
Cu m /L 0.01266* 1 t <0.0008 0.0009 0.0014 0.0009 0.0017 0.0009 0.0009 0.0009
F m /L 1.8 2 <0.15 0.19 0.22 0.18 0.26 0.17 0.17 0.17
Fe m /L -- 0.3t 1.56 1.06 1.15 1.12 1.17 1.36 1.35 1.36
_Hg m /L 0.000012t 0.001 t 0.0000008 0.000001 0.0000011 0.0000009 0.0000012 0.0000009 0.0000009 0.0000009
K m /L -- -- 2.7 2.97 3.32 2.98 3.88 2.89 2.88 2.89
Li m /L -- -- 0.05 0.07 0.16 0.08 0.30 0.07 0.07 0.08
-Mg m /L -- -- 1.04 1.73 1.78 1.60 2.01 1.35 1.34 1.35
Mn m /L -- 0.05t 0.84 0.84 0.83 0.81 0.84 0.84 0.84 0.84
Mo m /L -- -- 0.002 0.001 0.002 0.001 0.003 0.002 0.002 0.002
Na m /L -- -- 7.91 9.3 10.2 9.07 10.8 8.57 8.54 8.59
Ni m /L 0.07329* 0.1t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P m /L -- -- <0.1 0.1 0.19 0.11 0.24 0.11 0.10 0.11
Pb m /L 0.0039* 0.015t <0.0001 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002
Sb m /L -- 0.001t <0.0004 <0.0004 0.0007 0.0004 0.0010 0.0005 0.0004 0.0005
Se m /L 0.0031§ 0.02t <0.0001 <0.0001 0.0002 0.0001 0.0002 0.0001 0.0001 0.0001
Si m /L -- -- 8.92 10.9 11.2 10.5 11.5 9.77 9.75 9.78
Sn m /L -- -- <0.04 <0.04 0.04 0.04 0.04 <0.04 <0.04 <0.04
SO4 m /L -- 250 <1 3.78 5.57 3.68 9.46 2.67 2.58 2.72
Sr m /L -- -- 0.01 0.03 0.09 0.03 0.12 0.02 0.02 0.03
TI m /L -- 0.002f 0.0005 0.0003 0.0003 0.0003 0.0003 0.0004 0.0004 0.0004
U m /L -- -- 0.0008 0.002 0.002 0.002 0.002 0.001 0.001 0.001
V m /L -- -- <0.0005 0.0007 0.006 0.001 0.008 0.001 0.001 0.001
Zn m /L 0.16522* 1 t 0.03 0.011 0.02 0.02 0.02 0.02 0.02 0.02
NO3 m /L as NO3 -- 44.3 Not analyzed 2.28 0.10 4.28 0.11 0.07 0.13
TDS calc m /L -- 500 40.3 52.3 83.5 60.7 95.3 55.9 55.1 56.1
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity.Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration
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Table 6-11: Predicted Water Quality in the Archdale TSF Contact Water Pond (Base Case)
North North Predicted Water Quality in Contact Pond During Predicted Water Quality in ContactEMaximum
Carolina Carolina Operations Closure
Parameter Units Surface Groundwater
Water Standard Average Minimum Maximum Average Minimum
Standard'H S.U. 6.0-9.0 6.5-8.5 7.18 6.75 7.41
Alkalinity mg/L as CaCO3 >20** -- 164 143 193
-Ag m /L 0.00006 0.02t <0.0001 <0.0001 <0.0001
Al m /L -- -- 0.15 0.13 0.23
As m /L 0.15 0.01 t 0.002 0.001 0.003
B m /L -- 0.7t 0.14 0.12 0.16
Ba m /L -- 0.7t 0.043 0.039 0.048
Be m /L 0.0065 -- 0.0003 0.0002 0.0003
Ca m /L -- -- 30.0 25.3 35.0
Cd m /L 0.00097* 0.002t 0.0003 0.0002 0.0003
Cl m /L 230 250 8.36 7.32 8.76
Co m /L -- -- 0.0028 0.0020 0.0031
Cr m /L -- 0.01 t 0.0007 0.0006 0.0007
Cu m /L 0.01266* 1 t 0.004 0.004 0.005
F m /L 1.8 2 0.30 0.26 0.34
Fe m /L -- 0.3t 0.76 0.50 0.85
_Hg m /L 0.000012t 0.001 t 0.0000011 0.0000009 0.0000013
K m /L -- -- 3.10 2.56 3.83
Li m /L -- -- 0.28 0.20 0.43 Contact water pond will no longer be in operation
-Mg m /L -- -- 1.88 1.67 2.18 during post-closure period
Mn m /L -- 0.05t 0.55 0.35 0.61
_MO m /L -- -- 0.007 0.006 0.008
Na m /L -- -- 14.6 13.7 14.8
Ni m /L 0.07329* 0.1t 0.003 0.003 0.003
P m /L -- -- 0.72 0.63 0.87
Pb m /L 0.0039* 0.015t 0.0002 0.0002 0.0003
Sb m /L -- 0.001t 0.0016 0.0013 0.0018
Se m /L 0.0031§ 0.02t 0.0001 0.0001 0.0002
Si m /L -- -- 12.1 11.0 12.6
Sn m /L -- -- 0.04 0.04 0.05
SO4 m /L -- 250 5.79 4.03 10.3
Sr m /L -- -- 0.49 0.42 0.61
TI m /L -- 0.002t 0.0002 0.0002 0.0002
U m /L -- -- 0.002 0.002 0.002
V m /L -- -- 0.038 0.033 0.048
Zn m /L 0.16522* 1 t 0.03 0.03 0.04
NO3 m /L as NO3 -- 44.3 12.2 9.8 14.5
TDS (calc) m /L -- 500 187 164 208
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity.Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration
Table 6-12: Predicted Water Quality in Archdale Creek(Base Case)
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North North Existing Surface Water Predicted Water Quality in Archdale Creek During Predicted Water Quality in Archdale Creek
Carolina Carolina Quality in Archdale Operations Post-Closure
Parameter Units Surface Groundwater Creek(average of US
Water Average Minimum Maximum Average Minimum Maximum
Standard Dixon and UT Dixon)
)
H S.U. 6.0-9.0 6.5-8.5 6.90 7.07 6.73 7.33 7.30 7.11 7.33
Alkalinity m /L as CaCO3 >20** -- 22.1 129 118 135 31 28 60
-Ag m /L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al m /L - -- 0.12 0.16 0.13 0.23 0.07 0.07 0.11
As m /L 0.15 0.011t 0.0004 0.001 0.001 0.003 0.000 0.000 0.001
B m /L -- 0.7t <0.03 0.11 0.10 0.11 0.05 0.04 0.05
Ba m /L -- 0.7t <0.009 0.036 0.033 0.038 0.014 0.013 0.020
Be m /L 0.0065 -- <0.00008 0.0003 0.0003 0.0003 0.0005 0.0004 0.0005
Ca m /L -- -- 5.10 23.9 21.4 26.6 4.4 4.0 10.4
Cd m /L 0.00097* 0.002t <0.00005 0.0003 0.0003 0.0003 0.0003 0.0002 0.0003
-Cl m /L 230 250 5.35 8.36 7.59 8.70 6.03 5.86 6.92
Co m /L -- -- 0.0003 0.0031 0.0028 0.0033 0.0025 0.0024 0.0028
Cr m /L -- 0.011t <0.0005 0.0007 0.0006 0.0007 0.0005 0.0005 0.0006
Cu m /L 0.01266* 1 t <0.0008 0.003 0.003 0.004 0.001 0.001 0.002
F m /L 1.8 2 <0.15 0.27 0.24 0.32 0.16 0.15 0.20
Fe m /L -- 0.3t 0.24 0.88 0.79 0.93 1.23 1.16 1.35
_Hg m /L 0.000012t 0.001 t 0.80 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K m /L -- -- 2.00 3.19 2.75 3.84 2.64 2.57 2.97
Li m /L -- -- 0.01 0.25 0.18 0.39 0.07 0.07 0.14
-Mg m /L -- -- 1.75 1.87 1.64 2.13 1.24 1.20 1.48
Mn m /L -- 0.05t 0.19 0.63 0.57 0.66 0.76 0.74 0.84
Mo m /L -- -- <0.0002 0.005 0.005 0.006 0.002 0.002 0.003
Na m /L -- -- 5.26 13.2 12.2 13.8 7.9 7.6 9.7
Ni m /L 0.07329* 0.1t 0.0004 0.003 0.003 0.003 0.002 0.002 0.002
P m /L -- -- <0.1 0.55 0.50 0.59 0.19 0.14 0.24
Pb m /L 0.0039* 0.015t 0.00015 0.0003 0.0002 0.0003 0.0002 0.0002 0.0002
Sb m /L -- 0.001t <0.0004 0.0013 0.0011 0.0016 0.0004 0.0004 0.0007
Se m /L 0.0031§ 0.02t <0.0001 0.0002 0.0001 0.0002 0.0001 0.0001 0.0001
Si m /L -- -- 4.26 11.8 10.8 12.3 8.9 8.7 10.1
Sn m /L -- -- <0.04 0.04 0.04 0.04 0.04 0.04 0.04
SO4 m /L -- 250 5.00 5.92 4.12 10.12 2.51 2.38 3.93
Sr m /L -- -- 0.01095 0.37 0.33 0.39 0.03 0.02 0.13
TI m /L -- 0.002t <0.0001 0.0003 0.0002 0.0003 0.0004 0.0003 0.0004
U m /L -- -- 0.00012 0.002 0.002 0.002 0.001 0.001 0.001
V m /L -- -- <0.0005 0.028 0.025 0.030 0.001 0.001 0.009
Zn m /L 0.16522* 1 t <0.006 0.03 0.03 0.03 0.02 0.02 0.02
NO3 m /L as NO3 -- 44.3 Not analyzed 9.22 7.81 11.40 0.24 0.10 2.62
TDS (calc) mg/L -- 500 38.0 156 143 170 53 50 85
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity.Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration
Table 6-13: Predicted Groundwater Quality Underlying the Archdale TSF (Equilibrium Sensitivity Analysis)
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2023 PFS Report-Water Quality Predictions for the Archdale Project Page 45
North Existing Saprolite Existing Weathered Bedrock
North Groundwater Quality(average Predicted Groundwater Quality During Predicted Groundwater Quality Post-
Carolina Groundwater Quality Y g Y
Carolina of wells SNKM23-511, Operations Closure
Parameter Units Surface Groundwater (average of wells SNKM23-527, SNKM23-529, p
Water Standard SNKM23-531A and SNKM23-540A, SNKM23-550
Standard' SNKM23-553) and SNKM23-557) Average Minimum Maximum Average Minimum Maximum
H s.u. 6.0-9.0 6.5-8.5 7.48 7.34 7.04 6.76 7.29 7.34 7.32 7.36
-Alkalinity m /L as CaCO3 >20** -- 29.8 30.5 51.7 32.4 61.2 32.4 31.8 32.6
-Ag m /L 0.00006 0.02t <0.0001 0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al m /L -- -- 0.02 0.15 0.16 0.13 0.22 0.08 0.08 0.08
As m /L 0.15 0.01 t 0.0003 0.0003 0.001 0.0005 0.002 0.0005 0.0005 0.0005
B m /L -- 0.7t <0.03 <0.03 0.05 0.03 0.05 0.03 0.03 0.03
Ba m /L -- 0.7t 0.013 0.016 0.019 0.015 0.022 0.014 0.014 0.015
Be m /L 0.0065 -- 0.00064 0.00034 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005
Ca m /L -- -- 2.85 5.47 9.70 5.42 12.1 4.50 4.35 4.56
Cd m /L 0.00097* 0.002t 0.00028 0.00029 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
_Cl m /L 230 250 5.11 8.72 8.35 7.93 8.56 6.61 6.60 6.62
Co mg/L -- -- 0.002 0.004 0.0038 0.0036 0.0038 0.0028 0.0028 0.0028
Cr m /L -- 0.01 t 0.0005 0.0006 0.0006 0.0006 0.0007 0.0006 0.0006 0.0006
Cu m /L 0.01266* 1 t <0.0008 0.0009 0.0014 0.0009 0.0017 0.0009 0.0009 0.0009
F m /L 1.8 2 <0.15 0.19 0.22 0.18 0.26 0.17 0.17 0.17
Fe m /L - 0.3t 1.56 1.06 1.15 1.12 1.17 1.36 1.35 1.36
_Hg mg/L 0.000012t 0.001t 0.0000008 0.000001 0.0000010 0.0000009 0.0000012 0.0000009 0.0000009 0.0000009
K m /L - -- 2.7 2.97 3.32 2.98 3.88 2.89 2.87 2.89
Li m /L - -- 0.05 0.07 0.16 0.08 0.30 0.07 0.07 0.08
-Mg m /L - -- 1.04 1.73 1.78 1.60 2.01 1.35 1.34 1.35
Mn m /L -- 0.05t 0.84 0.84 0.83 0.81 0.84 0.84 0.84 0.84
Mo mg/L -- -- 0.002 0.001 0.002 0.001 0.003 0.002 0.002 0.002
Na m /L -- -- 7.91 9.3 10.2 9.07 10.8 8.57 8.54 8.59
Ni m /L 0.07329* 0.1t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P m /L -- -- <0.1 0.1 0.19 0.11 0.24 0.11 0.10 0.11
Pb m /L 0.0039* 0.015t <0.0001 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002
Sb m /L -- 0.001t <0.0004 <0.0004 0.0006 0.0004 0.0009 0.0005 0.0004 0.0005
Se m /L 0.0031§ 0.02t <0.0001 <0.0001 0.0002 0.0001 0.0002 0.0001 0.0001 0.0001
Si m /L -- -- 8.92 10.9 5.22 4.90 5.39 4.57 4.56 4.57
Sn mg/L -- -- <0.04 <0.04 0.04 0.04 0.04 <0.04 <0.04 <0.04
SO4 m /L -- 250 <1 3.78 5.57 3.68 9.46 2.67 2.58 2.72
Sr m /L -- -- 0.01 0.03 0.09 0.03 0.12 0.02 0.02 0.03
TI m /L -- 0.002t 0.0005 0.0003 0.0003 0.0003 0.0003 0.0004 0.0004 0.0004
U m /L -- -- 0.0008 0.002 0.002 0.002 0.002 0.001 0.001 0.001
V m /L -- -- <0.0005 0.0007 0.006 0.001 0.008 0.001 0.001 0.001
Zn m /L 0.16522* 1 t 0.03 0.011 0.02 0.02 0.02 0.02 0.02 0.02
NO3 m /L as NO3 -- 44.3 Not analyzed 2.28 0.10 4.28 0.11 0.07 0.13
TDS calc m /L -- 500 40.3 52.3 77.8 55.4 89.3 51.0 50.2 51.3
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
' North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity.Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration
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Table 6-14: Predicted Water Quality in the Archdale TSF Contact Water Pond (Equilibrium Sensitivity Analysis)
North North Predicted Water Quality in Contact Pond During Predicted Water Quality in Contact Pond Post-
Carolina Carolina Operations Closure
Parameter Units Surface Groundwater
Water Standard Average Minimum Maximum Average Minimum Maximum
Standard'
H S.U. 6.0-9.0 6.5-8.5 7.08 6.71 7.38
Alkalinity mg/L as CaCO3 >20** -- 159 140 191
-Ag m /L 0.00006 0.02t <0.0001 <0.0001 0.000
-Al m /L - -- <0.005 <0.005 <0.005
As m /L 0.15 0.01 t 0.001 0.001 0.003
B m /L -- 0.7t 0.13 0.12 0.16
Ba m /L -- 0.7t 0.042 0.038 0.048
Be m /L 0.0065 -- <0.00008 <0.00008 <0.00008
Ca m /L -- -- 29.7 25.3 35.1
Cd m /L 0.00097* 0.002t 0.0003 0.0002 0.0003
Cl m /L 230 250 8.37 7.33 8.78
Co m /L -- -- 0.0028 0.0020 0.0030
Cr m /L -- 0.01 t <0.0005 <0.0005 <0.0005
Cu m /L 0.01266* 1 t 0.002 0.001 0.002
F m /L 1.8 2 0.30 0.26 0.34
Fe m /L -- 0.3t 0.04 0.03 0.05
-Hg m /L 0.000012t 0.001 t 0.0000011 0.0000009 0.0000013
K m /L -- -- 3.14 2.56 3.83
Li m /L -- -- 0.29 0.20 0.43 Contact water pond will no longer be in operation
-Mg m /L -- -- 1.90 1.67 2.18 during post-closure period
Mn m /L -- 0.05t <0.01 <0.01 <0.01
Mo m /L -- -- 0.007 0.006 0.008
Na m /L -- -- 14.5 13.6 14.8
Ni m /L 0.07329* 0.1t 0.003 0.003 0.003
P m /L -- -- 0.36 0.26 0.64
Pb m /L 0.0039* 0.015t <0.0001 <0.0001 <0.0001
Sb m /L -- 0.001t 0.0011 0.0004 0.0017
Se m /L 0.0031§ 0.02t 0.0002 0.0001 0.0002
Si m /L -- -- 5.66 5.16 5.89
Sn m /L -- -- 0.04 0.04 0.05
SO4 m /L -- 250 6.08 4.03 10.3
Sr m /L -- -- 0.48 0.42 0.61
TI m /L -- 0.002t 0.0002 0.0002 0.0002
U m /L -- -- 0.002 0.002 0.002
V m /L -- -- 0.037 0.031 0.048
Zn m /L 0.16522* 1 t 0.03 0.02 0.03
NO3 m /L as NO3 -- 44.3 12.1 9.79 14.5
TDS calc m /L -- 500 177 156 201
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity.Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration
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2023 PFS Report-Water Quality Predictions for the Archdale Project Page 47
Table 6-15: Predicted Water Quality in Archdale Creek (Equilibrium Sensitivity Analysis)
North North Existing Surface Water Predicted Water Quality in Archdale Creek During Predicted Water Quality in Archdale Creek Post-
Carolina Carolina Quality in Archdale Operations Closure
Parameter Units Surface Groundwater Creek(average of US
Water Average Minimum Maximum Average Minimum Maximum
Standard Dixon and UT Dixon)
)
H s.u. 6.0-9.0 6.5-8.5 6.90 7.05 6.71 7.30 7.16 7.05 7.18
Alkalinity mg/L as CaCO3 >20** -- 22.1 126.7 115.7 132.4 28.9 26.7 58.1
-Ag m /L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al m /L - -- 0.12 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005
As m /L 0.15 0.01 t 0.0004 0.0011 0.0004 0.0022 <0.0002 <0.0002 <0.0002
B m /L -- 0.7t <0.03 0.11 0.10 0.11 0.05 0.04 0.05
Ba m /L -- 0.7t <0.009 0.036 0.033 0.038 0.014 0.013 0.020
Be m /L 0.0065 -- <0.00008 <0.00008 <0.00008 <0.00008 <0.00008 <0.00008 <0.00008
Ca m /L -- -- 5.10 23.9 21.4 26.7 4.44 4.04 10.4
Cd m /L 0.00097* 0.002t <0.00005 0.0003 0.0003 0.0003 0.0002 0.0002 0.0003
-Cl m /L 230 250 5.35 8.38 7.60 8.71 6.04 5.87 6.93
Co m /L -- -- 0.0003 0.0031 0.0028 0.0032 0.0025 0.0024 0.0027
Cr m /L -- 0.01 t <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005
Cu m /L 0.01266* 1 t <0.0008 0.0011 0.0010 0.0012 <0.0008 <0.0008 <0.0008
F m /L 1.8 2 <0.15 0.28 0.24 0.32 0.16 0.15 0.20
Fe m /L -- 0.3t 0.24 0.040 0.035 0.046 <0.007 <0.007 <0.007
_Hg m /L 0.000012t 0.001 t 0.80 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K m /L -- -- 2.00 3.19 2.75 3.84 2.64 2.57 2.97
Li m /L -- -- 0.01 0.25 0.18 0.39 0.07 0.07 0.14
-Mg m /L -- -- 1.75 1.87 1.64 2.13 1.24 1.20 1.48
Mn m /L -- 0.05t 0.19 0.01 0.01 0.01 0.59 0.35 0.62
Mo m /L -- -- <0.0002 0.005 0.005 0.006 0.002 0.001 0.003
Na m /L - -- 5.26 13.2 12.2 13.8 7.88 7.61 9.70
Ni m /L 0.07329* 0.1t 0.0004 0.003 0.003 0.003 0.002 0.002 0.002
P m /L -- -- <0.1 0.17 0.12 0.21 <0.1 <0.1 <0.1
Pb m /L 0.0039* 0.015t 0.00015 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Sb m /L -- 0.001t <0.0004 0.0009 0.0004 0.0013 0.0004 0.0004 0.0007
Se m /L 0.0031§ 0.02t <0.0001 0.0002 0.0001 0.0002 <0.0001 <0.0001 <0.0001
Si m /L -- -- 4.26 5.54 5.04 5.75 4.17 4.05 4.70
Sn m /L -- -- <0.04 0.04 0.04 0.04 0.04 0.04 0.04
SO4 m /L -- 250 5.00 5.92 4.12 10.12 2.51 2.37 3.93
Sr m /L -- -- 0.01095 0.37 0.33 0.39 0.03 0.02 0.13
TI m /L -- 0.002t <0.0001 0.0003 0.0002 0.0003 0.0004 0.0003 0.0004
U m /L -- -- 0.00012 0.002 0.002 0.002 0.001 0.001 0.001
V m /L -- -- <0.0005 0.027 0.024 0.028 0.002 0.002 0.002
Zn m /L 0.16522* 1t <0.006 0.03 0.02 0.03 0.02 0.02 0.02
NO3 m /L as NO3 -- 44.3 Not analyzed 9.22 7.81 11.4 0.24 0.10 2.62
TDS calc m /L -- 500 38.0 148 136 162 46.7 44.1 77.9
Indicates predicted concentration is greater than North Carolina surface water quality
0.01 standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity.Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration
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2023 PFS Report—Water Quality Predictions for the Archdale Project Page 48
7 Summary
SRK has undertaken water quality predictions to assess future contact water quality associated with
the Archdale TSF.
The base case water quality predictions use a mass balanced approach, whereby the tailings, waste
rock and groundwater source terms are mixed in the proportions provided in the water balance to
provide a mass balanced chemistry at the various water quality prediction points. This is considered a
conservative approach, as mineral precipitation and trace element sorption processes (i.e., processes
that may remove trace elements from solution) are not accounted for that will likely occur in nature. A
sensitivity analysis has been undertaken to evaluate the effect of incorporating mineral equilibration
and sorption on the resulting water chemistry.
The results show that predicted water quality in the contact water pond and Archdale Creek is circum-
neutral (pH 6.7 to 7.4), with all parameters predicted to be below North Carolina Surface Water
Standards. Post-closure,the contact water pond will no longer be operational. Groundwater underlying
the proposed TSF is also predicted to be circum-neutral (pH 6.7 to 7.3),with the majority of parameters
predicted to be below North Carolina Groundwater Quality Standards. The only exceptions are iron
and manganese, which are elevated in existing (i.e., baseline)groundwater at Archdale.
The results of the equilibration sensitivity analysis show that the equilibrated chemistry is similar to the
mass balanced chemistry, however predicted concentrations of iron, manganese, aluminum and
antimony are slightly lower for the equilibration sensitivity, reflecting the precipitation of ferrihydrite,
alunite, MnHPO4 and SbO2, with the latter including additional sorption processes onto iron oxides.
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SRK Consulting(U.S.), Inc.
2023 PFS Report—Water Quality Predictions for the Archdale Project Page 49
8 References
National Atmospheric Deposition Program (NADP), 2022. https://nadp.slh.wisc.edu/sites/ntn-NC34/,
accessed 12th December 2022.
Parkhurst, D.L.and Appelo, C.A.J., 1999. User's guide to PHREEQC(version 2)-A computer program
for speciation, batch-reaction, one-dimensional transport, and inverse geochemical
calculations: U.S. Geological Survey Water-Resources Investigations Report 99-4259, 312pp.
SRK, 2024a. Technical Report 2022 Prefeasibility Study Baseline Geochemistry Characterization.
Kings Mountain Mining Project. Report prepared for Albemarle, January 30, 2024.
SRK, 2024b. Draft Baseline Geochemistry Characterization Study for Archdale Tailings Facility, 2022
Prefeasibility Study. Kings Mountain Mining Project. Report prepared for Albemarle, March 12,
2024.
SRK, 2024c. Hydrogeological Assessment Study for Archdale Tailings Facility, Kings Mountain Mining
Project Prefeasibility Study. Report prepared for Albemarle, March 6, 2024.
SRK, 2024d. Archdale Water Balance: 'Annual flows and Monthly Flows — Model Export —
25MAR2024.xlsx'.
SRK, 2024e.Tailings tonnages. Personal communication with Breese Burnley dated 11th March 2024.
SRK, 2024f. Waste rock volumes. Personal communication with Joshua Sames dated 24th March
2024.
SRK, 2024g. Technical Report 2022 Prefeasibility Study Baseline Geochemistry: Water Quality
Predictions—DRAFT. Kings Mountain. Report prepared for Albemarle, January 19, 2024.
SRK, 2024h. Archdale Surface Water Management Report. Kings Mountain Ming Project. Report
prepared for Albemarle, April 2, 2024.
United States Environmental Protection Agency(US EPA), 1994. Method 1312. Synthetic Precipitation
Leaching Procedure. Revision 0. September 1994.
US EPA, 2012. Method 1313. Liquid-Solid Partitioning as a Function of Extract pH using a Parallel
Batch Extraction Procedure. Revision 0, October 2012
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SRK Consulting(U.S.), Inc.
2023 PFS Report—Water Quality Predictions for the Archdale Project Page 50
Disclaimer
The opinions expressed in this Report have been based on the information supplied to SRK Consulting
(U.S.), Inc. (SRK) by Albemarle Corporation (Albemarle). These opinions are provided in response to
a specific request from Albemarle to do so, and are subject to the contractual terms between SRK and
Albemarle. SRK has exercised all due care in reviewing the supplied information. Whilst SRK has
compared key supplied data with expected values, the accuracy of the results and conclusions from
the review are entirely reliant on the accuracy and completeness of the supplied data. SRK does not
accept responsibility for any errors or omissions in the supplied information and does not accept any
consequential liability arising from commercial decisions or actions resulting from them. Opinions
presented in this report apply to the site conditions and features as they existed at the time of SRK's
investigations, and those reasonably foreseeable. These opinions do not necessarily apply to
conditions and features that may arise after the date of this Report.
Copyright
This report is protected by copyright vested in SRK Consulting (U.S.), Inc. It may not be reproduced
or transmitted in any form or by any means whatsoever to any person without the written permission
of the copyright holder, SRK.
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2023 PFS Report—Water Quality Predictions for the Archdale Project Appendices
Appendices
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SRK Consulting(U.S.), Inc.
2023 PFS Report—Water Quality Predictions for the Archdale Project Appendices
Appendix A: Annual Water Quality Predictions (Base Case)
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Predicted Tailings Seepage/Runoff Chemistry [1] and [2]
North Carolina North Carolina TSF is uncovered Cover is TSF is covered
Parameter Units Surface Water Groundwater applied
Standard 1 Standard 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
pH s.u. 6.0-9.0 6.5-8.5 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20
Alkalinity mg/L as CaCO3 >20** -- 324 324 324 324 324 324 324 324 324 324 324 324 324 324 324 324
Ag*** mg/L 0.00006 0.02t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Al mg/L -- -- 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10
As mg/L 0.15 0.01 t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
B mg/L -- 0.7t 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27
Ba mg/L -- 0.7t 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076
Be mg/L 0.0065 -- 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005
Ca mg/L -- -- 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1
Cd mg/L 0.00097* 0.002t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 1 0.0002 0.0002 0.0002
CI mg/L 230 250 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06
Co mg/L -- -- 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008
Cr mg/L -- 0.01 t 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007
Cu mg/L 0.01266* it 0.01 0.01 0.01 0.01 1 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 1 0.01 0.01
F mg/L 1.8 2 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36
Fe mg/L -- 0.3t 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012
Hg mg/L 0.000012t 0.001 t 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 10.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009
K mg/L -- -- 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06
Li mg/L -- -- 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38
Mg mg/L -- -- 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68
Mn mg/L -- 0.05t 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005
Mo mg/L -- -- 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 1 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014
Na mg/L -- -- 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4
Ni mg/L 0.07329* 0.1t 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 1 0.005 0.005 0.005 0.005 0.005
P mg/L -- -- 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49 1.49
Pb mg/L 0.0039* 0.015t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Sb mg/L -- 0.001 t 0.003 0.003 0.003 1 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Se mg/L 0.0031§ 0.02t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 1 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Si mg/L -- -- 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8
Sn mg/L -- -- 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040
SO4 mg/L -- 250 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80
Sr mg/L -- -- 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09
TI mg/L -- 0.002t 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 1 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
V mg/L -- -- 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 1 0.086 1 0.086 1 0.086 0.086
Zn mg/L 0.16522* 1 t 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06
NO3 mg/L as NO3 -- 1 44.3 1 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 1 26.3
TDS(calc) mg/L I -- 1 500 1 325 1 325 1 325 325 325 325 325 325 325 325 325 325 325 325 325 325
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
***Silver is predicted to be above the most restrictive surface water quality standard, but this is an artifact of the elevated detection limit for silver in in laboratory SPLP and EPA 1313 tests(0.0001 mg/L compared to a surface water standard of 0.00006 mg/L).Silver is consistently below analytical
detection limits in the laboratory tests and the lysimeter installed in the existing TSF and is thus not likely to be a constituent of concern in future tailings seepage waters
§Lotic standard
t Represents total recoverable metal concentration

Predicted Tailings Seepage/Runoff Chemistry [1] and [2] (continued)
North Carolina North Carolina TSF is covered
Parameter Units Surface Water Groundwater
Standard 1 Standard 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
pH s.u. 6.0-9.0 6.5-8.5 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20
Alkalinity mg/L as CaCO3 >20** -- 324 324 324 324 324 324 324 324 324 324 324 324 324 324 324 324
Ag*** mg/L 0.00006 0.02t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Al mg/L -- -- 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10
As mg/L 0.15 0.01 t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
B mg/L -- 0.7t 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27 0.27
Ba mg/L -- 0.7t 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076 0.076
Be mg/L 0.0065 -- 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005 0.00005
Ca mg/L -- -- 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1 58.1
Cd mg/L 0.00097* 0.002t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
CI mg/L 230 250 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06 7.06
Co mg/L -- -- 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008
Cr mg/L -- 0.01 t 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007
Cu mg/L 0.01266* it 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 1 0.01 0.01 0.01 0.01 0.01 0.01 0.01
F mg/L 1.8 2 0.36 0.36 1 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36
Fe mg/L -- 0.3t 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012
Hg mg/L 0.000012t 0.001 t 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009 0.0000009
K mg/L -- -- 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06 2.06
Li mg/L -- -- 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 1 0.38 0.38 0.38 0.38 0.38 1 0.38 0.38 0.38
Mg mg/L -- -- 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68 1.68
Mn mg/L -- 0.05t 0.005 0.005 1 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005
Mo mg/L -- -- 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014
Na mg/L -- -- 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4
Ni mg/L 0.07329* 0.1t 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005
P mg/L -- -- 1.49 1.49 1.49 1 1.49 1.49 1.49 1.49 1.49 1.49 1 1.49 1.49 1.49 1.49 1.49 1.49 1.49
Pb mg/L 0.0039* 0.015t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Sb mg/L -- 0.001 t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Se mg/L 0.0031§ 0.02t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Si mg/L -- -- 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8
Sn mg/L -- -- 0.040 0.040 1 0.040 0.040 0.040 0.040 0.040 0.040 1 0.040 0.040 0.040 0.040 0.040 0.040 1 0.040 0.040
SO4 mg/L -- 250 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80 3.80
Sr mg/L -- -- 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09
TI mg/L -- 0.002t 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004 0.00004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
V mg/L -- -- 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086 0.086
Zn mg/L 0.16522* 1 t 0.06 0.06 0.06 1 0.06 0.06 0.06 0.06 0.06 1 0.06 1 0.06 0.06 0.06 0.06 0.06 1 0.06 0.06
NO3 mg/L as NO3 -- 1 44.3 1 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3
TDS(calc) mg/L -- 500 325 325 325 325 325 325 325 325 325 325 325 325 325 325 325 325
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
***Silver is predicted to be above the most restrictive surface water quality standard, but this is an artifact of the elevated detection limit for silver in in laboratory SPLP and EPA 1313 tests(0.0001 mg/L compared to a surface water standard of 0.00006 mg/L).Silver is consistently below analytical
detection limits in the laboratory tests and the lysimeter installed in the existing TSF and is thus not likely to be a constituent of concern in future tailings seepage waters
§Lotic standard
t Represents total recoverable metal concentration

Predicted Chemistry Resulting from Interaction of Groundwater with Tailings [3]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20
Alkalinity mg/L as CaCO3 >20** -- 354 354 354 354 354 354 354 354 354 354 354 354 354 354 354 354
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.17 0.17 0.17 0.17 0.17 0.17
As mg/L 0.15 0.01 t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
B mg/L -- 0.7t 0.30 1 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 1 0.30 0.30 0.30
Ba mg/L -- 0.7t 0.091 0.091 0.091 0.091 0.091 0.091 0.091 0.091 1 0.091 0.091 0.090 0.090 0.090 0.090 0.090 0.090
Be mg/L 0.0065 -- 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Ca mg/L -- -- 62.9 62.9 62.9 62.9 62.9 62.9 62.9 62.9 62.9 62.9 62.0 62.0 62.0 62.0 62.0 62.0
Cd mg/L 0.00097* 0.002t 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
CI mg/L 230 250 14.9 14.9 14.9 14.9 14.9 14.9 14.9 14.9 14.9 14.9 13.6 13.6 13.6 13.6 13.6 13.6
Co mg/L -- -- 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036
Cr mg/L -- 0.01t 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012
Cu mg/L 0.01266* it 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01
F mg/L 1.8 2 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.52 0.52 0.52 0.52 0.52 0.52
Fe mg/L -- 0.3t 1.19 1.19 1.19 1.19 1.19 1.19 1.19 1.19 1.19 1.19 1.37 1.37 1.37 1.37 1.37 1.37
Hg mg/L 0.000012t 0.001 t 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 1 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002
K mg/L -- -- 4.96 4.96 4.96 4.96 4.96 4.96 4.96 4.96 4.96 4.96 4.86 4.86 4.86 4.86 4.86 4.86
Li mg/L -- -- 0.44 0.44 0.44 0.44 0.44 0.44 0.44 0.44 0.44 0.44 0.43 0.43 0.43 0.43 0.43 0.43
Mg mg/L -- -- 3.25 3.25 3.25 1 3.25 3.25 3.25 3.25 3.25 3.25 3.25 2.99 2.99 2.99 2.99 2.99 2.99
Mn mg/L -- 0.05t 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85
Mo mg/L -- -- 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015
Na mg/L -- -- 28.4 28.4 28.4 28.4 28.4 28.4 28.4 28.4 28.4 28.4 27.9 27.9 27.9 27.9 27.9 27.9
Ni mg/L 0.07329* 0.1t 0.006 0.006 0.006 0.006 0.006 0.006 0.006 0.006 0.006 0.006 0.007 0.007 0.007 0.007 0.007 0.007
P mg/L -- -- 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59
Pb mg/L 0.0039* 0.015t 0.0004 0.0004 0.0004 1 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
Sb mg/L -- 0.001 t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
Si mg/L -- -- 22.2 22.2 22.2 22.2 22.2 22.2 22.2 22.2 22.2 22.2 21.5 21.5 21.5 21.5 21.5 21.5
Sn mg/L -- -- 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
SO4 mg/L -- 250 6.94 6.94 6.94 1 6.94 6.94 6.94 6.94 6.94 6.94 6.94 5.91 5.91 5.91 5.91 5.91 5.91
Sr mg/L -- -- 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11
TI mg/L -- 0.002t 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
U mg/L -- -- 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
V mg/L -- -- 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087
Zn mg/L 0.16522* 1 t 0.07 1 0.07 1 0.07 0.07 1 0.07 1 0.07 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08
NO3 mg/L as NO3 -- 44.3 26.3 26.3 26.3 1 26.3 26.3 26.3 26.3 26.3 26.3 1 26.3 26.3 1 26.3 26.3 26.3 26.3 26.3
TDS(calc) mg/L -- 500 383 383 383 383 383 383 1 383 383 383 383 378 378 378 378 378 378
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Chemistry Resulting from Interaction of Groundwater with Tailings [3] (continued)
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20 8.20
Alkalinity mg/L as CaCO3 >20** -- 354 354 354 354 354 354 354 354 354 354 354 354 354 354 354 354
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17
As mg/L 0.15 0.01 t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
B mg/L -- 0.7t 0.30 0.30 1 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30
Ba mg/L -- 0.7t 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090
Be mg/L 0.0065 -- 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Ca mg/L -- -- 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0 62.0
Cd mg/L 0.00097* 0.002t 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
CI mg/L 230 250 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6 13.6
Co mg/L -- -- 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036 0.0036
Cr mg/L -- 0.01t 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012 0.0012
Cu mg/L 0.01266* it 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01
F mg/L 1.8 2 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52 0.52
Fe mg/L -- 0.3t 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37
Hg mg/L 0.000012t 0.001 t 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 1 0.000002 0.000002
K mg/L -- -- 4.86 4.86 4.86 1 4.86 4.86 4.86 4.86 4.86 4.86 4.86 4.86 4.86 4.86 4.86 4.86 4.86
Li mg/L -- -- 0.43 0.43 0.43 0.43 0.43 0.43 0.43 0.43 1 0.43 0.43 0.43 0.43 0.43 0.43 0.43 0.43
Mg mg/L -- -- 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99
Mn mg/L -- 0.05t 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85
Mo mg/L -- -- 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015
Na mg/L -- -- 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9 27.9
Ni mg/L 0.07329* 0.1t 0.007 0.007 0.007 1 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007
P mg/L -- -- 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59
Pb mg/L 0.0039* 0.015t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
Sb mg/L -- 0.001 t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
Si mg/L -- -- 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5 21.5
Sn mg/L -- -- 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
SO4 mg/L -- 250 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91 5.91
Sr mg/L -- -- 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11
TI mg/L -- 0.002t 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
U mg/L -- -- 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
V mg/L -- -- 0.087 0.087 0.087 0.087 0.087 0.087 0.087 1 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087 0.087
Zn mg/L 0.16522* 1 t 1 0.08 1 0.08 0.08 0.08 0.08 0.08 0.08 0.08 1 0.08 0.08 1 0.08 0.08 0.08 0.08 0.08 0.08
NO3 mg/L as NO3 -- 44.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 26.3 1 26.3 26.3 26.3 26.3 26.3
TDS(calc) mg/L -- 1 500 378 378 378 378 378 378 378 378 378 378 378 378 378 378 378 378
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Chemistry in the Drains at the Base of the Waste Rock Embankment [4]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 5.68 5.69 5.70 5.70 6.38 6.39 6.39 6.39 6.09 5.73 5.69 5.68 5.67 5.66 5.65 5.65
Alkalinity mg/L as CaCO3 >20** -- 163 186 214 246 325 325 325 325 297 223 209 204 201 198 195 193
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al mg/L -- -- 0.78 0.95 1.23 1.57 0.42 0.42 0.42 0.42 0.61 1.11 1.19 1.22 1.25 1.27 1.28 1.30
As mg/L 0.15 0.01 t 0.014 0.017 0.022 0.028 0.006 0.006 0.006 0.006 0.010 0.020 0.021 0.022 0.023 0.023 0.023 0.024
B mg/L -- 0.7t 0.10 0.11 0.12 0.13 0.26 0.26 0.26 0.26 0.23 0.14 0.12 0.11 0.11 0.10 0.10 0.10
Ba mg/L -- 0.7t 0.026 0.027 0.028 0.029 0.079 0.079 0.079 0.079 0.066 0.034 0.027 0.025 0.024 0.022 0.021 0.021
Be mg/L 0.0065 -- 0.0003 0.0003 0.0003 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0003 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003
Ca mg/L -- -- 49.6 58.6 71.3 86.9 64.4 64.3 64.3 64.3 65.8 69.2 69.6 69.8 70.1 70.1 70.2 70.3
Cd mg/L 0.00097* 0.002t 0.0001 0.0002 0.0002 0.0002 0.0004 0.0004 0.0004 0.0005 0.0004 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001
CI mg/L 230 250 8.78 10.17 12.0 14.2 14.3 14.3 14.3 14.3 13.7 12.1 11.4 11.3 11.2 11.2 11.1 11.1
Co mg/L -- -- 0.0013 0.0014 0.0014 0.0015 0.0040 0.0040 0.0040 0.0040 0.0033 0.0017 0.0011 0.0010 0.0009 0.0009 0.0009 0.0008
Cr mg/L -- 0.01 t <0.0005 <0.0005 <0.0005 <0.0005 0.0011 0.0011 0.0011 0.0011 0.0009 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005
Cu mg/L 0.01266* it 0.003 0.003 0.003 0.003 0.008 0.008 0.008 0.008 0.007 0.004 0.003 0.003 0.003 0.003 0.003 0.002
F mg/L 1.8 2 0.70 0.84 1.05 1.32 0.63 0.63 0.63 0.63 0.73 0.98 1.03 1.04 1.06 1.06 1.07 1.08
Fe mg/L -- 0.3t 0.33 0.36 0.37 1 0.37 1.02 1.02 1.02 1.02 0.86 0.44 0.42 0.38 0.36 0.34 0.33 0.31
Hg mg/L 0.000012t 0.001 t 0.000003 0.000003 0.000004 0.000005 0.000002 0.000002 0.000002 0.000002 0.000003 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004
K mg/L -- -- 8.48 10.3 13.0 16.4 6.5 6.5 6.5 6.5 8.1 12.0 12.7 13.0 13.2 13.3 13.5 13.6
Li mg/L -- -- 1.65 2.03 2.61 3.35 0.87 0.86 0.86 0.86 1.29 2.36 2.56 2.63 2.68 2.72 2.75 2.78
Mg mg/L -- -- 3.93 4.72 5.89 7.36 3.76 3.76 3.75 3.75 4.26 5.54 5.70 5.79 5.86 5.90 5.94 5.98
Mn mg/L -- 0.05t 0.27 0.30 0.32 0.34 0.74 0.74 0.74 0.74 0.63 0.36 0.31 0.29 0.28 0.27 0.26 0.25
MO mg/L -- -- 0.004 0.005 0.005 0.005 0.013 0.013 0.013 0.013 0.011 0.006 0.005 0.004 0.004 1 0.004 0.004 0.003
Na mg/L -- -- 14.6 16.8 19.6 22.9 26.6 26.6 26.6 26.6 24.8 20.1 19.0 18.7 18.6 18.4 18.2 18.1
Ni mg/L 0.07329* 0.1t 0.002 0.003 0.003 0.003 0.006 0.006 0.006 0.006 0.005 0.003 0.003 0.003 0.003 0.003 0.003 0.003
P mg/L -- -- 0.48 0.52 0.54 0.57 1.38 1.38 1.38 1.38 1.17 0.63 0.53 0.50 0.47 0.45 0.43 0.42
Pb mg/L 0.0039* 0.015t 0.0003 0.0004 0.0005 0.0006 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
Sb mg/L -- 0.001 t 0.004 0.005 0.006 0.008 0.004 0.004 0.004 0.004 0.004 0.006 0.006 1 0.006 0.007 0.007 0.007 0.007
Se mg/L 0.0031§ 0.02t 0.0010 0.0012 0.0016 0.0020 0.0005 0.0005 0.0005 0.0005 0.0007 0.0014 0.0015 0.0016 0.0016 0.0016 0.0017 0.0017
Si mg/L -- -- 12.4 14.4 17.0 20.1 21.1 21.1 21.1 21.1 20.0 17.2 16.4 16.3 16.2 16.0 15.9 15.9
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 0.07 0.07 0.07 0.07 1 0.06 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 46.5 57.2 74.1 95.4 20.2 20.1 20.0 20.0 33.2 66.5 72.4 74.6 76.2 77.4 78.5 79.4
Sr mg/L -- -- 0.37 0.41 0.45 0.48 0.98 0.98 0.98 0.98 0.84 0.50 0.43 0.41 0.40 0.38 0.37 0.36
TI mg/L -- 0.002t 0.0002 0.0003 0.0003 0.0004 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
U mg/L -- -- 0.002 0.003 0.003 0.004 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
V mg/L -- -- 0.024 0.026 0.027 0.027 0.075 0.075 0.075 0.075 0.063 0.032 0.026 0.024 0.023 0.022 0.021 0.020
Zn mg/L 1 0.16522* 1 1 t 0.02 0.02 0.02 0.02 1 0.06 1 0.06 0.06 0.06 0.05 0.03 0.02 0.02 0.02 0.02 0.02 0.02
3 mg as 3 __ 44.3 24.7 24.0 45.5 52.1 23.0 23.0 23.0 23.0 19.7 11.2 9.6 9.1 8.7 8.4 8.1 1 7.8
TDS(calc) mg/L -- 500 269 311 1 390 468 376 376 1 376 376 369 351 1 346 345 345 343 343 342
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
'*No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Chemistry in the Drains at the Base of the Waste Rock Embankment [4] (continued)
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 5.64 5.64 5.63 5.63 5.62 5.62 5.62 5.61 5.61 5.61 5.61 5.61 5.61 5.62 5.62 5.62
Alkalinity mg/L as CaCO3 >20** -- 192 189 187 185 184 182 181 181 181 180 180 180 181 181 181 182
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al mg/L -- -- 1.31 1.32 1.34 1.35 1.36 1.37 1.37 1.38 1.38 1.38 1.38 1.37 1.38 1.37 1.37 1.36
As mg/L 0.15 0.01 t 0.024 0.024 0.024 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025
B mg/L -- 0.7t 0.10 0.09 1 0.09 0.09 0.09 0.09 0.08 1 0.08 0.08 0.08 0.08 0.08 0.08 1 0.08 0.08 0.08
Ba mg/L -- 0.7t 0.020 0.019 0.018 0.017 0.016 0.016 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.016 0.016
Be mg/L 0.0065 -- 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
Ca mg/L -- -- 70.5 70.4 70.5 70.6 70.8 70.6 70.7 70.7 70.8 70.6 70.6 70.5 70.7 70.5 70.4 70.4
Cd mg/L 0.00097* 0.002t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
CI mg/L 230 250 11.1 11.0 11.0 11.0 11.0 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9
Co mg/L -- -- 0.0008 0.0007 1 0.0007 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Cr mg/L -- 0.01 t <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005
Cu mg/L 0.01266* it 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
F mg/L 1.8 2 1.09 1.09 1.10 1.10 1.11 1.11 1.12 1.12 1.12 1.12 1.12 1.12 1.12 1.11 1.11 1.11
Fe mg/L -- 0.3t 0.30 0.29 0.27 0.26 0.25 0.24 0.24 0.23 0.23 1 0.23 0.23 0.23 0.23 0.23 1 0.24 0.24
Hg mg/L 0.000012t 0.001 t 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004
K mg/L -- -- 13.7 13.7 13.9 14.0 14.1 14.1 14.1 14.2 14.2 14.2 14.2 14.1 14.2 14.1 14.1 14.0
Li mg/L -- -- 2.81 2.84 2.86 2.89 2.92 2.93 2.94 2.95 2.96 2.95 2.95 2.95 2.95 2.94 2.93 2.92
Mg mg/L -- -- 6.02 6.05 6.08 6.11 6.15 6.16 6.17 6.18 6.20 6.18 6.18 6.17 6.18 6.16 6.15 6.14
Mn mg/L -- 0.05t 0.24 0.24 0.23 0.22 0.22 0.21 0.21 0.21 0.21 0.20 0.20 0.21 0.21 0.21 0.21 0.21
MO mg/L -- -- 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 1 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Na mg/L -- -- 18.0 17.8 17.7 17.6 17.5 17.4 17.3 17.3 17.3 17.2 17.2 17.2 17.3 17.2 17.3 17.3
Ni mg/L 0.07329* 0.1t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P mg/L -- -- 0.40 0.39 0.37 0.36 0.35 0.34 0.33 0.33 0.33 0.32 0.32 0.33 0.33 0.33 0.33 0.34
Pb mg/L 0.0039* 0.015t 0.0004 0.0004 0.0004 1 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
Sb mg/L -- 0.001 t 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007
Se mg/L 0.0031§ 0.02t 0.0017 0.0017 0.0017 0.0017 0.0018 0.0018 0.0018 0.0018 1 0.0018 0.0018 0.0018 0.0018 0.0018 0.0018 0.0018 0.0018
Si mg/L -- -- 15.8 15.7 15.6 15.6 15.5 15.5 15.4 15.4 15.4 15.4 15.4 15.4 15.4 1 15.4 15.4 15.4
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 80.4 81.1 82.0 82.8 83.7 84.0 84.4 84.6 84.9 84.7 84.6 84.5 84.6 84.2 84.0 83.7
Sr mg/L -- -- 0.35 0.34 0.33 0.33 0.32 0.31 0.31 0.30 0.30 0.30 0.30 0.30 0.31 0.31 0.31 0.31
TI mg/L -- 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
U mg/L -- -- 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 1 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
V mg/L -- -- 0.019 0.018 0.017 0.016 0.016 0.015 0.015 0.015 0.015 0.014 0.014 0.015 0.015 0.015 0.015 0.015
Zn mg/L 1 0.16522* 1 1 t 1 0.02 0.02 0.02 0.01 0.01 1 0.01 1 0.01 0.01 0.01 0.01 0.01 1 0.01 0.01 0.01 0.01 0.01
3 mg as 3 __ 44.3 7.6 7.4 7.2 1 6.9 6.8 6.6 6.5 6.4 6.4 1 6.4 6.4 6.4 6.5 6.5 1 6.5 6.6
TDS(calc) mg/L -- 500 342 341 340 1 340 340 339 338 338 339 1 338 338 338 338 337 1 337 337
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
'*No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Chemistry in the Drains at the Base of the TSF [5]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040+
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 6.75 6.65 6.69 6.71 7.48 7.34 7.34 7.34 7.30 7.22 6.93 6.84
Alkalinity mg/L as CaCO3 >20- -- 159 167 168 169 149 161 162 162 189 210 119 86.0
Ag- mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
AI mg/L -- -- 0.16 0.19 0.21 0.23 0.12 0.13 0.13 0.13 0.13 0.13 0.16 0.17
As mg/L 0.15 0.01 t 0.002 0.003 0.003 0.003 0.001 0.001 0.001 0.001 0.001 0.002 0.002 0.002
B mg/L -- 0.7t 0.13 0.14 0.14 0.14 0.13 1 0.14 0.14 0.14 0.16 0.17 1 0.10 0.07
Ba mg/L -- 0.7t 0.041 0.042 0.042 0.041 0.040 0.043 0.043 0.043 0.048 0.052 0.033 0.025
Be mg/L 0.0065 -- 0.0003 0.0002 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0003 0.0003
Ca mg/L -- __ 29.6 32.1 32.9 33.6 26.5 28.9 29.0 28.9 34.1 38.0 22.3 16.7
Cd mg/L 0.00097' 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
CI mg/L 230 250 7.62 7.77 7.92 8.08 7.65 7.87 7.87 7.87 7.66 7.49 7.80 7.93
Co mg/L -- -- 0.0024 0.0023 0.0024 0.0024 0.0026 0.0026 0.0026 0.0026 0.0023 0.0020 0.0029 0.0032
Cr mg/L -- 0.01 t 0.0006 0.0006 0.0006 0.0006 0.0006 0.0007 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006
Cu mg/L 0.01266* it 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.005 0.006 0.003 0.002
mg 1.8 2 0.29 0.32 0.33 0.35 0.25 0.27 0.27 0.27 0.29 0.30 0.26 0.25
e mg -- 0.3t 0.64 0.61 0.62 0.63 0.72 0.71 0.70 0.71 1 0.57 0.47 0.82 0.95
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K mg/L -- -- 2.97 3.28 3.46 1 3.70 2.62 2.74 2.74 2.74 2.65 2.60 3.09 3.29 TSF sump
Li mg/L __ -- 0.31 0.38 0.42 0.47 0.20 0.23 0.23 0.23 0.27 0.30 0.26 0.25 no longer
g mg -- 1.79 1.92 2.01 2.10 1.64 1.72 1.72 1.72 1.72 1.72 1.78 1.81 operational
n mg. 0.05t 0.46 0.44 0.45 0.46 0.51 0.50 0.50 0.50 0.41 0.33 0.59 0.68
Mo mg/L -- -- 0.007 0.007 0.007 0.007 0.006 0.007 0.007 0.007 0.008 0.009 0.005 0.003
Na mg/L -- -- 13.6 14.1 14.3 1 14.5 13.3 14.0 14.0 14.0 14.9 15.5 12.3 11.2
Ni mg/L 0.07329* 0.1t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.004 0.003 0.002
P mg/L -- -- 0.69 0.72 0.72 0.71 0.66 0.72 0.72 0.72 0.85 0.94 0.51 0.34
m9 0.0039* 0.015t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0003
mg -- 0.001 t 0.002 0.002 0.002 0.002 0.001 0.001 0.001 1 0.001 0.002 0.002 0.001 0.001
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0003 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002
Si mg/L -- -- 11.1 11.4 11.6 11.8 11.1 11.5 11.5 11.5 11.4 11.4 11.1 10.9
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 0.04 0.04 0.04 0.04 0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 6.55 8.70 9.80 11.18 3.62 4.21 4.22 4.22 4.51 4.93 6.25 6.96
Sr mg/L -- -- 0.48 0.50 0.50 0.50 0.45 0.49 0.50 0.49 0.60 0.67 0.34 0.21
TI mg/L -- 0.002t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0003
U mg/L -- -- 0.002 1 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
V mg/L -- -- 0.037 0.038 0.038 0.038 0.035 0.038 0.038 0.038 0.046 0.052 0.025 0.015
Zn mg/L 0.16522* 1 t 0.03 0.03 0.03 0.03 0.03 1 0.03 0.03 0.03 0.04 0.04 0.03 0.02
NO3 mg/L as NO3 -- 1 44.3 12.4 13.2 15.0 15.2 10.6 11.6 11.6 1 11.6 14.1 15.9 7.7 1 4.7
TDS(calc) mg/L -- 1 500 182 193 199 202 167 180 180 180 205 224 1 144 116
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
"No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Toe Seepage Chemistry at the Base of the Embankment [6]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 5.68 5.69 5.70 5.70 6.38 6.39 6.39 6.39 6.09 5.73 5.69 5.68 5.67 5.66 5.65 5.65
Alkalinity mg/L as CaCO3 >20** -- 163 186 214 246 325 325 325 325 297 223 209 204 201 198 195 193
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al mg/L -- -- 0.78 0.95 1.23 1.57 0.42 0.42 0.42 0.42 0.61 1.11 1.19 1.22 1.25 1.27 1.28 1.30
As mg/L 0.15 0.01 t 0.014 0.017 0.022 0.028 0.006 0.006 0.006 0.006 0.010 0.020 0.021 0.022 0.023 0.023 0.023 0.024
B mg/L -- 0.7t 0.10 0.11 0.12 0.13 0.26 0.26 0.26 0.26 0.23 0.14 0.12 0.11 0.11 0.10 0.10 0.10
Ba mg/L -- 0.7t 0.026 0.027 0.028 0.029 0.079 0.079 0.079 0.079 0.066 0.034 0.027 0.025 0.024 0.022 0.021 0.021
Be mg/L 0.0065 -- 0.0003 0.0003 0.0003 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0003 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003
Ca mg/L -- -- 49.6 58.6 71.3 86.9 64.4 64.3 64.3 64.3 65.8 69.2 69.6 69.8 70.1 70.1 70.2 70.3
Cd mg/L 0.00097* 0.002t 0.0001 0.0002 0.0002 0.0002 0.0004 0.0004 0.0004 0.0005 0.0004 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001
CI mg/L 230 250 8.78 10.2 12.0 14.2 14.3 14.3 14.3 14.3 13.7 12.1 11.4 11.3 11.2 11.2 11.1 11.1
Co mg/L -- -- 0.0013 0.0014 0.0014 0.0015 0.0040 0.0040 0.0040 0.0040 0.0033 0.0017 0.0011 0.0010 0.0009 0.0009 0.0009 0.0008
Cr mg/L -- 0.01 t <0.0005 <0.0005 <0.0005 <0.0005 0.0011 0.0011 0.0011 0.0011 0.0009 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005
Cu mg/L 0.01266* it 0.003 0.003 0.003 0.003 0.008 0.008 0.008 0.008 0.007 0.004 0.003 0.003 0.003 0.003 0.003 0.002
F mg/L 1.8 2 0.70 0.84 1.05 1.32 0.63 0.63 0.63 0.63 0.73 0.98 1.03 1.04 1.06 1.06 1.07 1.08
Fe mg/L -- 0.3t 0.33 0.36 0.37 1 0.37 1.02 1.02 1.02 1.02 0.86 0.44 0.42 0.38 0.36 0.34 0.33 0.31
Hg mg/L 0.000012t 0.001 t 0.000003 0.000003 0.000004 0.000005 0.000002 0.000002 0.000002 0.000002 0.000003 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004
K mg/L -- -- 8.48 10.28 13.02 16.44 6.53 6.52 6.51 6.51 1 8.08 12.02 12.74 12.99 13.19 13.32 13.45 13.55
Li mg/L -- -- 1.65 2.03 2.61 3.35 0.87 0.86 0.86 0.86 1.29 2.36 2.56 2.63 2.68 2.72 2.75 2.78
Mg mg/L -- -- 3.93 4.72 5.89 7.36 3.76 3.76 3.75 3.75 4.26 5.54 5.70 5.79 5.86 5.90 5.94 5.98
Mn mg/L -- 0.05t 0.27 0.30 0.32 0.34 0.74 0.74 0.74 0.74 0.63 0.36 0.31 0.29 0.28 0.27 0.26 0.25
MO mg/L -- -- 0.004 0.005 0.005 0.005 0.013 0.013 0.013 0.013 0.011 0.006 0.005 0.004 0.004 1 0.004 0.004 0.003
Na mg/L -- -- 14.6 16.8 19.6 22.9 26.6 26.6 26.6 26.6 24.8 20.1 19.0 18.7 18.6 18.4 18.2 18.1
Ni mg/L 0.07329* 0.1t 0.002 0.003 0.003 0.003 0.006 0.006 0.006 0.006 1 0.005 0.003 0.003 0.003 0.003 0.003 0.003 0.003
P mg/L -- -- 0.48 0.52 0.54 0.57 1.38 1.38 1.38 1.38 1.17 0.63 0.53 0.50 0.47 0.45 0.43 0.42
Pb mg/L 0.0039* 0.015t 0.0003 0.0004 0.0005 0.0006 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
Sb mg/L -- 0.001 t 0.004 0.005 0.006 0.008 0.004 0.004 0.004 0.004 0.004 0.006 0.006 1 0.006 0.007 0.007 0.007 0.007
Se mg/L 0.0031§ 0.02t 0.0010 0.0012 0.0016 0.0020 0.0005 0.0005 0.0005 0.0005 0.0007 0.0014 0.0015 0.0016 0.0016 0.0016 0.0017 0.0017
Si mg/L -- -- 12.4 14.4 17.0 20.1 21.1 21.1 21.1 21.1 20.0 17.2 16.4 16.3 16.2 16.0 15.9 15.9
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 0.07 0.07 0.07 0.07 1 0.06 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 46.5 57.2 74.1 95.4 20.2 20.1 20.0 20.0 33.2 66.5 72.4 74.6 76.2 77.4 78.5 79.4
Sr mg/L -- -- 0.37 0.41 0.45 0.48 0.98 0.98 0.98 0.98 0.84 0.50 0.43 0.41 0.40 0.38 0.37 0.36
TI mg/L -- 0.002t 0.0002 0.0003 0.0003 0.0004 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
U mg/L -- -- 0.002 0.003 0.003 0.004 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
V mg/L -- -- 0.024 0.026 0.027 0.027 0.075 0.075 0.075 0.075 1 0.063 0.032 0.026 0.024 0.023 0.022 0.021 0.020
Zn mg/L 0.16522* 1 t 0.02 0.02 0.02 0.02 0.06 0.06 0.06 0.06 0.05 0.03 0.02 0.02 0.02 0.02 0.02 0.02
NO3 mg/L as NO3 -- 44.3 24.7 24.0 45.5 52.1 23.0 23.0 23.0 23.0 19.7 11.2 9.6 9.1 8.7 8.4 8.1 1 7.8
TDS(calc) mg/L -- 500 269 311 1 390 468 376 376 376 376 369 351 1 346 345 345 343 343 342
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
'*No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Toe Seepage Chemistry at the Base of the Embankment [6] (continued)
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 5.64 5.64 5.63 5.63 5.62 5.62 5.62 5.61 5.61 5.61 5.61 5.61 5.61 5.62 5.62 5.62
Alkalinity mg/L as CaCO3 >20** -- 192 189 187 185 184 182 181 181 181 180 180 180 181 181 181 182
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
-Al mg/L -- -- 1.31 1.32 1.34 1.35 1.36 1.37 1.37 1.38 1.38 1.38 1.38 1.37 1.38 1.37 1.37 1.36
As mg/L 0.15 0.01 t 0.024 0.024 0.024 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025
B mg/L -- 0.7t 0.10 0.09 0.09 0.09 0.09 0.09 0.08 1 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
Ba mg/L -- 0.7t 0.020 0.019 0.018 0.017 0.016 0.016 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.016 0.016
Be mg/L 0.0065 -- 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
Ca mg/L -- -- 70.5 70.4 70.5 70.6 70.8 70.6 70.7 70.7 70.8 70.6 70.6 70.5 70.7 70.5 70.4 70.4
Cd mg/L 0.00097* 0.002t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
CI mg/L 230 250 11.1 11.0 11.0 11.0 11.0 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9
Co mg/L -- -- 0.0008 0.0007 0.0007 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Cr mg/L -- 0.01 t <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005
Cu mg/L 0.01266* 1 t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
F mg/L 1.8 2 1.09 1.09 1.10 1.10 1.11 1.11 1.12 1.12 1.12 1.12 1.12 1.12 1.12 1.11 1.11 1.11
Fe mg/L -- 0.3t 0.30 0.29 0.27 0.26 0.25 0.24 0.24 0.23 0.23 1 0.23 0.23 0.23 0.23 0.23 1 0.24 0.24
Hg mg/L 0.000012t 0.001 t 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004 0.000004
K mg/L -- -- 13.68 13.75 13.85 13.95 14.06 14.09 14.13 14.16 14.20 14.17 14.15 14.14 14.16 14.10 14.07 14.04
Li mg/L -- -- 2.81 2.84 2.86 2.89 2.92 2.93 2.94 2.95 2.96 2.95 2.95 2.95 2.95 2.94 2.93 2.92
Mg mg/L -- -- 6.02 6.05 6.08 6.11 6.15 6.16 6.17 6.18 6.20 6.18 6.18 6.17 6.18 6.16 6.15 6.14
Mn mg/L -- 0.05t 0.24 0.24 0.23 0.22 0.22 0.21 0.21 0.21 0.21 0.20 0.20 0.21 0.21 0.21 0.21 0.21
MO mg/L -- -- 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 1 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Na mg/L -- -- 18.0 17.8 17.7 17.6 17.5 17.4 17.3 17.3 17.3 17.2 17.2 17.2 17.3 17.2 17.3 17.3
Ni mg/L 0.07329* 0.1t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P mg/L -- -- 0.40 0.39 0.37 0.36 0.35 0.34 0.33 0.33 0.33 0.32 0.32 0.33 0.33 0.33 0.33 0.34
Pb mg/L 0.0039* 0.015t 0.0004 0.0004 0.0004 1 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
Sb mg/L -- 0.001 t 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007
Se mg/L 0.0031§ 0.02t 0.0017 0.0017 0.0017 0.0017 0.0018 0.0018 0.0018 0.0018 1 0.0018 0.0018 0.0018 0.0018 0.0018 0.0018 0.0018 0.0018
Si mg/L -- -- 15.8 15.7 15.6 15.6 15.5 15.5 15.4 15.4 15.4 15.4 15.4 15.4 15.4 1 15.4 15.4 15.4
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 80.4 81.1 82.0 82.8 83.7 84.0 84.4 84.6 84.9 84.7 84.6 84.5 84.6 84.2 84.0 83.7
Sr mg/L -- -- 0.35 0.34 0.33 0.33 0.32 0.31 0.31 0.30 0.30 0.30 0.30 0.30 0.31 0.31 0.31 0.31
TI mg/L -- 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
U mg/L -- -- 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 1 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
V mg/L -- -- 0.019 0.018 0.017 0.016 0.016 0.015 0.015 0.015 0.015 0.014 0.014 0.015 0.015 0.015 0.015 0.015
Zn mg/L 1 0.16522* 1 1 t 1 0.02 0.02 0.02 0.01 0.01 1 0.01 1 0.01 0.01 0.01 0.01 0.01 1 0.01 0.01 0.01 0.01 0.01
NO3 mg/L as NO3 -- 44.3 7.6 7.4 7.2 1 6.9 6.8 6.6 6.5 6.4 6.4 1 6.4 6.4 6.4 6.5 6.5 1 6.5 6.6
TDS(calc) mg/L -- 500 342 341 340 340 340 339 338 338 339 338 338 338 338 337 337 337
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
'*No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Groundwater Quality Underneath TSF [7]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 6.75 6.76 6.76 1 6.76 7.17 7.18 7.18 7.18 7.20 7.24 7.29 7.29 7.29 1 7.29 7.29 7.28
Alkalinity mg/L as CaCO3 >20** -- 45.4 50.2 52.2 54.3 57.2 60.6 60.7 60.7 40.1 32.0 31.3 31.9 31.8 31.8 31.8 31.8
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.16 0.18 0.19 0.22 0.14 0.14 0.14 0.14 0.13 0.13 0.08 0.08 0.08 0.08 0.08 0.08
As mg/L 0.15 0.01 t 0.001 0.001 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000
B mg/L -- 0.7t 0.04 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.04 0.03 0.03 0.03 1 0.03 0.03 0.03 0.03
Ba mg/L -- 0.7t 0.017 0.018 0.018 1 0.018 0.021 0.022 0.022 0.022 0.017 0.015 0.014 0.015 0.014 0.014 0.014 0.014
Be mg/L 0.0065 -- 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
Ca mg/L -- -- 8.9 10.1 11.0 12.1 10.1 10.7 10.8 10.8 7.0 5.4 4.4 4.5 4.4 4.4 4.4 4.5
Cd mg/L 0.00097* 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
CI mg/L 230 250 8.08 8.25 8.37 8.52 8.47 8.55 8.55 8.55 8.10 7.92 6.59 6.60 6.60 6.60 6.60 6.60
Co mg/L -- -- 0.0036 0.0037 0.0037 0.0037 0.0038 0.0038 0.0038 0.0038 0.0038 0.0038 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028
Cr mg/L -- 0.01 t 0.0006 0.0006 0.0006 0.0006 0.0007 0.0007 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Cu mg/L 0.01266* it 0.001 0.001 0.001 0.001 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
F mg/L 1.8 2 0.22 0.23 0.25 0.26 0.22 0.22 0.22 0.22 0.20 0.18 0.17 0.17 0.17 0.17 0.17 0.17
Fe mg/L -- 0.3t 1.12 1.12 1.12 1.12 1.17 1.17 1.17 1.17 1.17 1.17 1.36 1.36 1.36 1.36 1.36 1.36
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K mg/L -- -- 3.31 3.46 3.64 3.88 3.20 3.21 3.22 3.21 3.06 2.98 2.88 2.88 2.88 2.88 2.88 2.88
Li mg/L -- -- 0.18 0.20 0.25 0.30 0.13 0.13 0.13 0.13 0.10 0.08 0.07 0.07 0.07 0.07 0.07 0.07
Mg mg/L -- -- 1.76 1.83 1.91 2.01 1.75 1.77 1.77 1.77 1 1.66 1.60 1.34 1.35 1.35 1.35 1.35 1.35
Mn mg/L -- 0.05t 0.81 0.81 0.81 0.81 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84
Mo mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.003 0.003 0.003 0.002 0.001 0.002 0.002 0.002 0.002 0.002 0.002
Na mg/L -- -- 9.73 10.1 10.3 10.5 10.6 10.8 10.8 10.8 9.6 9.1 8.5 8.6 8.6 8.6 8.6 8.6
Ni mg/L 0.07329* 0.1t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P mg/L -- -- 0.16 0.17 0.18 0.18 0.22 0.24 0.24 0.24 0.14 0.11 0.10 0.11 0.11 0.11 0.11 0.11
Pb mg/L 0.0039* 0.015t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
Sb mg/L -- 0.001 t 0.0007 0.0008 0.0009 0.0010 0.0007 0.0007 0.0007 0.0007 0.0005 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Si mg/L -- -- 10.8 11.0 11.2 11.4 11.4 11.5 11.5 11.5 10.8 10.5 9.7 9.8 9.8 9.8 9.8 9.8
Sn mg/L -- -- <0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 6.07 6.84 8.01 9.46 4.38 4.40 4.40 4.40 4.01 3.68 2.60 2.58 2.58 2.58 2.60 2.62
Sr mg/L -- -- 0.07 0.08 0.09 0.09 0.11 0.12 0.12 0.12 0.06 0.03 0.02 0.02 0.02 0.02 0.02 0.02
TI mg/L -- 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0004 0.0004 0.0004 1 0.0004 0.0004 0.0004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001
V mg/L -- -- 0.004 0.005 0.005 0.005 0.007 0.008 0.008 0.008 0.003 0.001 0.001 0.001 0.001 0.001 0.001 0.001
Zn mg/L 0.16522* 1 t 0.02 0.02 0.02 0.02 1 0.02 0.02 1 0.02 0.02 0.02 1 0.02 1 0.02 1 0.02 0.02 0.02 0.02 1 0.02
NO3 mg/L as NO3 -- 44.3 1 2.14 2.36 3.83 4.28 2.12 2.39 2.40 1 2.40 0.74 0.10 0.07 0.12 0.11 0.11 0.11 1 0.11
TDS(calc) mg/L -- 500 1 78.4 84.5 90.1 95.3 86.7 90.1 90.2 1 90.2 69.3 60.7 55.1 55.7 55.6 55.6 55.6 1 55.7
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Groundwater Quality Underneath TSF [7] (continued)
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 7.28 7.28 7.27 1 7.27 7.27 7.26 7.26 7.26 1 7.26 7.26 7.26 7.26 7.26 7.26 1 7.26 7.26
Alkalinity mg/L as CaCO3 >20** -- 31.8 31.9 31.9 31.9 31.9 31.9 31.9 32.0 32.0 32.0 32.0 32.0 32.1 32.1 32.1 32.1
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
As mg/L 0.15 0.01 t 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
B mg/L -- 0.7t 0.03 0.03 1 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03
Ba mg/L -- 0.7t 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014 1 0.014 0.014 0.014 0.014 0.014 0.014 0.014 0.014
Be mg/L 0.0065 -- 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
Ca mg/L -- -- 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.6 4.6 4.6
Cd mg/L 0.00097* 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
CI mg/L 230 250 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.61 6.61 6.61 6.61 6.61 6.61 6.61 6.61
Co mg/L -- -- 0.0028 0.0028 0.0028 1 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028 0.0028
Cr mg/L -- 0.01 t 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 1 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Cu mg/L 0.01266* it 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
F mg/L 1.8 2 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17 0.17
Fe mg/L -- 0.3t 1.36 1.36 1.36 1.36 1.36 1.36 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 1 0.000001 0.000001
K mg/L -- -- 2.88 2.88 2.89 1 2.89 2.89 2.89 2.89 2.89 2.89 2.89 2.89 2.89 2.89 2.89 2.89 2.89
Li mg/L -- -- 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 1 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
Mg mg/L -- -- 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35
Mn mg/L -- 0.05t 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84
Mo mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
Na mg/L -- -- 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6
Ni mg/L 0.07329* 0.1t 0.002 0.002 0.002 1 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P mg/L -- -- 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11
Pb mg/L 0.0039* 0.015t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
Sb mg/L -- 0.001 t 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
Se mg/L 0.0031§ 0.02t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Si mg/L -- -- 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 2.64 2.65 2.67 2.68 2.69 2.70 2.71 2.71 2.72 2.72 2.72 1 2.72 2.72 2.72 2.72 2.71
Sr mg/L -- -- 0.02 0.02 0.02 0.02 0.02 0.02 0.02 1 0.02 0.02 0.02 0.02 0.02 1 0.02 0.03 0.03 0.03
TI mg/L -- 0.002t 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
U mg/L -- -- 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
V mg/L -- -- 0.001 0.001 1 0.001 1 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
Zn mg/L 0.16522* 1 t 1 0.02 0.02 0.02 0.02 1 0.02 1 0.02 0.02 0.02 0.02 0.02 1 0.02 0.02 0.02 0.02 0.02 0.02
NO3 mg/L as NO3 -- 44.3 0.11 0.11 0.11 0.11 0.11 0.11 1 0.11 0.11 0.12 0.12 0.12 1 0.12 0.12 0.12 0.13 0.13
TDS(calc) mg/L -- 500 55.7 55.8 55.8 55.8 55.9 55.9 55.9 56.0 56.0 56.0 56.0 1 56.1 1 56.1 56.1 56.1 56.1
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Water Quality in Trench Adjacent to TSF [8]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 6.83 6.88 6.88 1 6.88 7.26 7.31 7.31 7.31 7.26 1 7.08 6.81 6.76 6.64 6.56 1 6.48 6.42
Alkalinity mg/L as CaCO3 >20** -- 116.1 143.4 145.0 145 128 156 156 156 106.1 34.7 40.5 125.6 127.8 128.0 127.6 127.6
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.18 0.19 0.21 0.23 0.16 0.17 0.17 0.17 0.15 0.14 0.14 0.18 0.21 0.23 0.26 0.28
As mg/L 0.15 0.01 t 0.001 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.002 0.002 0.003 0.003 0.004 0.004
B mg/L -- 0.7t 0.10 1 0.12 0.12 0.12 0.11 0.13 0.13 0.13 0.09 0.03 0.04 0.10 1 0.10 0.10 0.10 0.10
Ba mg/L -- 0.7t 0.034 0.041 0.041 0.040 0.038 0.045 0.045 0.045 1 0.033 0.016 0.015 0.035 0.034 0.034 0.033 0.032
Be mg/L 0.0065 -- 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
Ca mg/L -- -- 21.4 26.5 27.1 27.8 22.8 27.7 27.8 27.8 18.8 6.3 7.7 23.5 24.7 25.6 26.4 27.2
Cd mg/L 0.00097* 0.002t 0.0003 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
CI mg/L 230 250 9.65 10.3 10.4 10.5 10.0 10.6 10.6 10.6 9.54 7.98 6.84 8.71 8.78 1 8.80 8.82 8.83
Co mg/L -- -- 0.0039 0.0039 0.0039 1 0.0039 0.0040 0.0041 0.0041 0.0041 0.0040 0.0037 0.0027 0.0029 0.0028 0.0028 1 0.0027 0.0026
Cr mg/L -- 0.01 t 0.0008 0.0008 0.0008 0.0008 0.0008 0.0009 0.0009 0.0009 1 0.0008 0.0006 0.0005 0.0007 0.0007 0.0007 0.0007 0.0007
Cu mg/L 0.01266* it 0.003 0.004 0.004 0.004 0.003 0.004 0.004 0.004 0.003 0.001 0.001 0.003 0.003 0.003 0.003 0.003
F mg/L 1.8 2 0.29 0.33 0.34 0.35 0.29 0.32 0.32 0.32 0.27 0.20 0.21 0.32 0.34 0.35 0.37 0.39
Fe mg/L -- 0.3t 1.13 1.14 1.14 1.14 1.17 1.17 1.17 1.17 1.17 1.16 1.31 1.30 1.27 1.25 1.22 1.20
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000002
K mg/L -- -- 3.71 3.94 4.09 4.27 3.63 3.79 3.79 3.79 3.48 3.11 3.39 4.05 4.30 4.51 4.74 4.94
Li mg/L -- -- 0.24 0.28 0.32 0.35 0.20 0.23 0.23 0.23 0.18 0.12 0.20 0.33 0.40 0.45 0.51 0.56
Mg mg/L -- -- 2.11 2.28 2.34 2.41 2.12 2.26 2.26 2.26 2.00 1.66 1.57 2.06 2.16 2.25 2.34 2.41
Mn mg/L -- 0.05t 0.81 0.82 0.82 0.82 0.84 0.84 0.84 0.84 0.84 0.83 0.81 0.81 0.79 0.78 0.76 0.75
Mo mg/L -- -- 0.005 0.006 0.006 0.006 0.005 0.007 0.007 0.007 0.004 0.001 0.002 0.005 0.005 0.005 0.005 0.005
Na mg/L -- -- 14.0 15.7 15.8 15.9 14.9 16.5 16.5 16.5 13.5 9.2 9.1 14.2 14.3 14.3 14.3 14.3
Ni mg/L 0.07329* 0.1t 0.003 0.003 0.003 0.003 0.003 0.004 0.004 0.004 0.003 0.002 0.002 0.003 0.003 0.003 0.003 0.003
P mg/L -- -- 0.48 0.61 0.61 0.61 0.55 0.68 0.68 0.68 0.45 0.11 0.13 0.51 0.51 0.50 0.49 0.48
Pb mg/L 0.0039* 0.015t 0.0003 0.0003 0.0003 0.0003 0.0003 1 0.0003 0.0003 0.0003 0.0003 0.0003 1 0.0002 0.0002 0.0002 0.0002 0.0003 1 0.0003
Sb mg/L -- 0.001 t 0.0012 0.0015 0.0016 0.0016 0.0012 0.0015 0.0015 0.0015 0.0011 0.0005 0.0007 0.0015 0.0016 0.0017 0.0019 0.0020
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0002 0.0001 0.0002 0.0002 0.0002 0.0001 0.0001 0.0002 0.0002 0.0003 0.0003 0.0003 0.0004
Si mg/L -- -- 13.4 14.5 14.6 14.7 14.0 15.0 15.0 15.0 13.2 10.6 10.1 13.2 13.3 13.3 13.3 13.3
Sn mg/L -- -- 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.05 <0.04 <0.04 0.05 0.05 0.05 0.05 0.05
SO4 mg/L -- 250 6.43 7.09 8.00 9.14 5.07 5.30 5.30 5.30 4.74 4.57 6.24 8.19 10.01 11.66 13.45 14.99
Sr mg/L -- -- 0.31 0.40 0.40 0.40 0.35 0.44 0.45 0.45 0.28 0.04 0.04 0.33 0.33 0.33 0.32 0.31
TI mg/L -- 0.002t 0.0003 0.0003 0.0003 1 0.0003 0.0003 0.0003 0.0003 0.0003 1 0.0003 0.0003 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.001 0.002 0.002 0.002 0.002 0.002
V mg/L -- -- 0.023 0.030 0.030 0.030 0.026 0.034 0.034 0.034 0.021 0.001 0.002 0.024 0.024 0.024 0.023 0.023
Zn mg/L 0.16522* 1 t 0.03 0.03 0.03 0.03 0.03 0.04 0.04 0.04 0.03 0.02 0.02 0.04 1 0.04 0.04 1 0.03 0.03
NO3 mg/L as NO3 -- 44.3 1 7.72 9.75 10.88 11.14 7.90 1 10.15 10.18 10.18 6.11 0.25 1 0.57 7.40 7.45 7.35 7.19 1 7.07
TDS(calc) mg/L -- 1 500 1 149 177 181 184 158 1 185 186 186 135.5 64.8 70.3 157.3 162.4 1 165 168 1 170
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Water Quality in Trench Adjacent to TSF [8] (continued)
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 6.38 6.35 6.32 1 6.29 6.27 6.25 6.24 6.22 1 6.21 6.20 6.20 6.19 6.18 6.18 1 6.17 6.17
Alkalinity mg/L as CaCO3 >20** -- 127.5 127.5 127.9 128.2 128.9 129.7 130.7 131.7 133.1 134.4 135.7 136.9 138.2 139.5 141.0 142.5
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.30 0.32 0.34 0.35 0.37 0.38 0.39 0.40 0.41 0.42 0.42 0.43 0.43 0.44 0.44 0.44
As mg/L 0.15 0.01 t 0.005 0.005 0.005 0.006 0.006 0.006 0.006 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007
B mg/L -- 0.7t 0.10 0.10 1 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10
Ba mg/L -- 0.7t 0.032 0.031 0.031 0.030 0.030 0.030 0.030 0.030 1 0.030 0.030 0.030 0.031 0.031 0.031 0.031 0.031
Be mg/L 0.0065 -- 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
Ca mg/L -- -- 27.8 28.3 29.0 29.5 30.1 30.6 31.1 31.6 32.1 32.5 32.9 33.3 33.7 34.0 34.4 34.7
Cd mg/L 0.00097* 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
CI mg/L 230 250 8.85 8.86 8.89 8.91 8.93 8.96 8.99 9.02 9.06 9.09 9.12 9.15 9.18 9.21 9.25 9.28
Co mg/L -- -- 0.0026 0.0026 0.0025 1 0.0025 0.0025 0.0025 0.0024 0.0024 0.0024 0.0024 0.0024 0.0024 0.0024 0.0024 0.0024 0.0024
Cr mg/L -- 0.01 t 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006
Cu mg/L 0.01266* it 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
F mg/L 1.8 2 0.40 0.41 0.42 0.43 0.44 0.45 0.46 0.46 0.47 0.47 0.48 0.48 0.49 0.49 0.50 0.50
Fe mg/L -- 0.3t 1.18 1.17 1.15 1.14 1.13 1.12 1.11 1.10 1.09 1.08 1.08 1.07 1.07 1.07 1.06 1.06
Hg mg/L 0.000012t 0.001 t 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 0.000002 1 0.000002 0.000002
K mg/L -- -- 5.11 5.25 5.39 1 5.52 5.64 5.74 5.84 5.92 6.00 6.05 6.11 6.16 6.21 6.24 6.28 6.31
Li mg/L -- -- 0.61 0.64 0.68 0.72 0.75 0.77 0.80 0.82 0.84 0.85 0.87 0.88 0.89 0.90 0.91 0.92
Mg mg/L -- -- 2.48 2.54 2.59 2.65 2.69 2.74 2.78 2.81 2.85 2.87 2.90 2.92 2.94 2.96 2.98 3.00
Mn mg/L -- 0.05t 0.74 0.73 0.72 0.72 0.71 0.70 0.70 0.69 0.69 0.69 0.68 0.68 0.68 0.68 0.67 0.67
Mo mg/L -- -- 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005
Na mg/L -- -- 14.3 14.3 14.3 14.3 14.4 14.4 14.5 14.5 14.6 14.7 14.7 14.8 14.9 15.0 15.1 15.1
Ni mg/L 0.07329* 0.1t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
P mg/L -- -- 0.47 0.47 0.46 0.46 0.46 0.46 0.46 0.46 0.46 0.47 0.47 0.47 0.48 0.48 0.49 0.49
Pb mg/L 0.0039* 0.015t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
Sb mg/L -- 0.001 t 0.0020 0.0021 0.0022 0.0023 0.0023 0.0024 0.0024 0.0025 0.0025 0.0026 0.0026 0.0026 0.0027 0.0027 0.0027 0.0027
Se mg/L 0.0031§ 0.02t 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0006 0.0006 0.0006 0.0006 0.0006
Si mg/L -- -- 13.3 13.3 13.3 13.3 13.3 13.4 13.4 13.4 13.5 13.5 13.6 13.6 13.7 13.7 13.8 13.8
Sn mg/L -- -- 0.04 0.04 0.04 1 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04
SO4 mg/L -- 250 16.29 17.40 18.51 19.49 20.41 21.16 21.86 22.45 1 23.01 23.42 23.78 24.11 24.45 24.67 24.92 25.13
Sr mg/L -- -- 0.31 0.31 0.31 0.30 0.30 0.31 0.31 0.31 0.31 0.32 0.32 0.32 0.33 0.33 0.33 0.34
TI mg/L -- 0.002t 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
V mg/L -- -- 0.022 0.022 1 0.022 1 0.021 0.021 0.021 0.021 0.021 0.022 0.022 0.022 0.022 0.023 0.023 0.023 0.023
Zn mg/L 0.16522* 1 1 t 1 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 1 0.03 1 0.03 0.03 0.03 0.03 0.03
NO3 mg/L as NO3 -- 1 44.3 6.98 6.89 6.85 6.81 6.79 6.81 6.84 1 6.88 1 6.95 7.03 7.11 7.19 1 7.27 7.36 7.47 7.58
TDS(calc) mg/L -- 1 500 173 174 177 179 181 183 185 1 187 1 189 191 193 195 1 197 198 200 202
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Water Quality in Contact Water Pond [9]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 6.78 6.72 6.75 1 6.77 7.41 7.34 7.34 7.34 7.30 1 7.22 6.93 6.76
Alkalinity mg/L as CaCO3 >20- -- 145 159 160 161 143 159 159 159 175 193 107 125
Ag- mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
AI mg/L -- -- 0.16 0.19 0.21 0.23 0.13 0.14 0.14 0.14 0.13 0.13 0.15 0.18
As mg/L 0.15 0.01 t 0.002 0.002 0.003 0.003 0.001 0.001 0.001 0.001 0.001 0.002 0.002 0.002
B mg/L -- 0.7t 0.12 0.13 0.13 0.13 0.12 1 0.13 0.14 0.13 0.15 0.16 1 0.09 0.10
Ba mg/L __ 0.7t 0.038 0.041 0.041 1 0.041 0.039 0.043 0.043 0.043 0.045 0.048 0.030 0.035
Be mg/L 0.0065 -- 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0003 0.0005
Ca mg/L __ -- 26.9 30.2 30.9 31.6 25.3 28.4 28.5 28.5 31.5 35.0 20.0 23.4
Cd mg/L 0.00097' 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0003 0.0003
CI mg/L 230 250 8.14 8.49 8.62 8.76 8.28 8.69 8.70 8.70 7.83 1 7.32 7.44 8.70
Co mg/L -- -- 0.0028 0.0028 0.0028 0.0028 0.0030 0.0031 0.0031 0.0031 0.0025 0.0020 0.0027 0.0029
Cr mg/L -- 0.01 t 0.0006 0.0007 0.0007 1 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0006 0.0006 0.0007
Cu mg/L 0.01266* it 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.005 0.005 0.003 0.003
mg 1.8 2 0.29 0.32 0.33 0.34 0.26 0.29 0.29 0.29 0.28 0.29 0.25 0.32
e mg -- 0.3t 0.78 0.77 0.78 0.78 0.84 0.85 0.85 0.85 1 0.65 0.50 0.84 1.29
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K mg/L -- -- 3.15 3.44 3.62 3.83 2.89 3.05 3.05 3.06 2.73 2.56 3.01 4.05
Li mg/L __ -- 0.28 0.35 0.38 0.43 0.20 0.23 0.23 0.23 0.25 0.28 0.24 0.33
g mg -- -- 1.86 2.01 2.09 2.18 1.77 1.88 1.88 1.88 1.74 1.67 1.69 2.06
n mg __ 0.05t 0.56 0.55 0.56 0.56 0.60 0.61 0.61 0.61 0.46 0.35 0.59 0.81
MO mg/L -- -- 0.006 0.006 0.006 0.006 0.006 0.007 0.007 0.007 0.007 0.008 0.004 0.005
Na mg/L -- -- 13.6 14.5 14.7 14.8 13.7 14.7 14.7 14.7 14.5 14.7 1 11.5 14.17
Ni mg/L 0.07329* 0.1t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
P mg/L -- -- 0.62 0.68 0.68 0.68 0.63 0.70 0.70 0.70 0.78 0.87 0.45 0.51
Pb m9 0.0039* 0.015t 0.0002 0.0002 0.0003 0.0003 0.0002 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002 0.0002
mg -- 0.001 t 0.0015 0.0017 0.0017 0.0018 0.0013 0.0014 0.0014 0.0014 0.0016 0.0017 0.0012 0.0015
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0002 0.0002
Si mg/L -- -- 11.7 12.2 12.4 12.6 11.9 12.5 12.5 12.5 11.5 11.0 10.6 13.2
Sn mg/L -- -- 0.04 0.04 0.04 1 0.04 0.04 0.05 0.05 0.05 0.04 <0.04 <0.04 0.05
SO4 mg/L -- 250 6.43 8.05 9.07 10.34 4.03 4.53 4.53 4.53 4.47 4.79 6.05 8.18
Sr mg/L -- -- 0.43 0.47 0.47 0.47 0.42 0.48 0.48 0.48 0.54 0.61 0.29 0.33
TI mg/L -- 0.002t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
V mg/L -- -- 0.032 0.036 0.036 0.035 0.033 0.037 0.037 0.037 0.042 0.048 0.022 0.024
Zn mg/L 0.16522* 1 t 0.03 0.03 0.03 1 0.03 1 0.03 1 0.03 1 0.03 0.03 0.04 0.04 0.03 0.04
NO3 mg/L as NO3 -- 1 44.3 10.9 12.1 13.6 13.8 9.8 11.1 11.1 1 11.1 12.8 14.5 6.67 7.39
TDS(calc) mg/L -- 1 500 170 187 192 195 164 181 181 1 181 193 208 132 157.0
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
"No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Water Quality in Archdale Creek [10]
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 6.77 6.73 6.75 1 6.77 7.33 7.29 7.29 7.29 7.27 1 7.23 7.11 7.22 7.33 7.33 1 7.32 7.32
Alkalinity mg/L as CaCO3 >20** -- 118 131 133 134 121 134 135 135 130 122 60 39 29 29 29 29
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.16 0.19 0.20 0.23 0.13 0.14 0.14 0.14 0.13 0.13 0.11 0.08 0.07 0.07 0.07 0.07
As mg/L 0.15 0.01 t 0.002 0.002 0.002 0.003 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.0004 0.0004 0.0004 0.0004
B mg/L -- 0.7t 0.10 0.11 0.11 0.11 0.10 0.11 0.11 0.11 0.11 0.10 0.05 0.04 <0.03 1 <0.03 <0.03 <0.03
Ba mg/L -- 0.7t 0.033 0.035 0.035 0.035 0.035 0.038 0.038 0.038 0.036 0.034 0.020 0.016 0.013 0.013 0.013 0.013
Be mg/L 0.0065 -- 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0004 0.0005 0.0005 0.0005 0.0005 0.0005
Ca mg/L -- -- 22.2 25.1 25.9 26.6 21.4 24.0 24.1 24.0 23.3 22.0 10.4 5.9 4.1 4.1 4.1 4.1
Cd mg/L 0.00097* 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
CI mg/L 230 250 8.12 8.43 8.56 8.70 8.33 8.65 8.66 8.66 7.92 7.59 6.92 6.77 6.09 6.08 6.06 6.04
Co mg/L -- -- 0.0030 0.0030 0.0030 1 0.0031 0.0032 0.0033 0.0033 0.0033 1 0.0029 0.0028 0.0027 0.0028 0.0025 0.0025 0.0025 0.0025
Cr mg/L -- 0.01 t 0.0006 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0005 0.0005 0.0005 0.0005
Cu mg/L 0.01266* it 0.003 0.003 0.003 0.003 0.003 0.004 0.004 0.004 0.004 0.003 0.002 0.001 0.001 0.001 <0.0008 <0.0008
F mg/L 1.8 2 0.27 0.29 0.31 0.32 0.25 0.27 0.27 0.27 0.25 0.24 0.20 0.18 0.16 0.16 0.16 0.16
Fe mg/L -- 0.3t 0.87 0.86 0.86 0.87 0.93 0.93 0.93 0.93 0.82 0.79 1.16 1.35 1.25 1.25 1.25 1.24
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K mg/L -- -- 3.19 3.45 3.62 3.84 2.97 3.09 3.09 3.10 2.84 2.75 2.93 2.97 2.65 2.65 2.64 2.64
Li mg/L -- -- 0.25 0.31 0.35 0.39 0.18 0.20 0.20 0.20 0.20 0.19 0.14 0.09 0.07 0.07 0.07 0.07
Mg mg/L -- -- 1.83 1.97 2.04 2.13 1.77 1.85 1.85 1.85 1.71 1.64 1.48 1.40 1.24 1.24 1.24 1.23
Mn mg/L -- 0.05t 0.63 0.62 0.62 0.63 0.66 0.66 0.66 0.66 0.59 0.57 0.74 0.84 0.77 0.77 0.77 0.77
Mo mg/L -- -- 0.005 0.005 0.005 0.005 0.005 0.006 0.006 0.006 0.005 0.005 0.003 0.002 0.002 0.002 0.002 0.002
Na mg/L -- -- 12.6 13.4 13.6 13.7 12.9 13.7 13.8 13.8 12.8 12.2 9.7 9.0 7.9 7.9 7.9 7.8
Ni mg/L 0.07329* 0.1t 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.002
P mg/L -- -- 0.50 0.55 0.55 0.55 0.52 0.59 0.59 0.59 0.57 0.53 0.24 0.14 <0.1 <0.1 <0.1 <0.1
Pb mg/L 0.0039* 0.015t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
Sb mg/L -- 0.001 t 0.0013 0.0014 0.0015 0.0016 0.0011 0.0013 0.0013 0.0013 0.0012 0.0012 0.0007 0.0005 0.0004 0.0004 1 0.0004 0.0004
Se mg/L 0.0031§ 0.02t 0.0002 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001
Si mg/L -- -- 11.4 11.9 12.1 12.3 11.7 12.3 12.3 12.3 11.3 10.8 10.1 10.0 9.01 8.99 8.97 8.94
Sn mg/L -- -- 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 <0.04 <0.04 0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 6.33 7.75 8.80 10.12 4.12 4.50 4.50 4.50 4.31 4.30 3.93 3.02 2.38 2.38 2.39 2.39
Sr mg/L -- -- 0.33 0.37 0.37 0.37 0.34 0.39 0.39 0.39 0.38 0.35 0.13 0.05 0.02 0.02 0.02 0.02
TI mg/L -- 0.002t 0.0003 0.0003 0.0003 1 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0003 0.0004 0.0004 0.0004 1 0.0004 0.0004
U mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001
V mg/L -- -- 0.025 0.028 0.028 0.028 0.026 0.030 0.030 0.030 0.029 0.027 0.009 0.003 0.001 0.001 0.001 0.001
Zn mg/L 0.16522* 1 t 0.03 0.03 0.03 0.03 0.03 1 0.03 1 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02
NO3 mg/L as NO3 -- 44.3 8.60 9.60 11.12 11.40 7.81 8.91 8.94 8.93 8.78 8.15 2.62 0.69 0.11 0.10 0.10 0.10
TDS(calc) mg/L -- 500 146 161 1 166 170 144 158 158 1 158 1 152 143 84.7 63.6 51.3 51.2 51.1 51.0
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration

Predicted Water Quality in Archdale Creek [10] (continued)
North Carolina North Carolina
Parameter Units Surface Water Groundwater 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
Standard 1 Standard
pH s.u. 6.0-9.0 6.5-8.5 7.32 7.32 7.31 1 7.31 7.31 7.31 7.31 7.31 1 7.31 7.31 7.31 7.31 7.31 7.31 1 7.31 7.31
Alkalinity mg/L as CaCO3 >20** -- 29 29 29 29 29 29 29 29 29 29 29 29 29 29 29 28
Ag*** mg/L 0.00006 0.02t <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Al mg/L -- -- 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07
As mg/L 0.15 0.01t 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
B mg/L -- 0.7t <0.03 <0.03 1 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03
Ba mg/L -- 0.7t 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 1 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013
Be mg/L 0.0065 -- 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005
Ca mg/L -- -- 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.0 4.0 4.0 4.0 4.0 4.0
Cd mg/L 0.00097* 0.002t 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002 0.0002
CI mg/L 230 250 6.02 6.00 5.99 5.97 5.96 5.94 5.93 5.92 5.91 5.90 5.89 5.89 5.88 5.87 5.87 5.86
Co mg/L -- -- 0.0025 0.0025 0.0025 1 0.0025 0.0025 0.0025 0.0025 0.0025 0.0025 0.0025 0.0025 0.0025 0.0024 0.0024 0.0024 0.0024
Cr mg/L -- 0.01 t 0.0005 0.0005 0.0005 0.0005 0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005
Cu mg/L 0.01266* it <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008 <0.0008
F mg/L 1.8 2 0.16 0.16 0.16 0.16 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15
Fe mg/L -- 0.3t 1.24 1.23 1.23 1.23 1.22 1.22 1.22 1.21 1.21 1.21 1.21 1.21 1.21 1.20 1.20 1.20
Hg mg/L 0.000012t 0.001 t 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001 0.000001
K mg/L -- -- 2.63 2.62 2.62 2.61 2.61 2.60 2.60 2.59 2.59 2.59 2.58 2.58 2.58 2.57 2.57 2.57
Li mg/L -- -- 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07
Mg mg/L -- -- 1.23 1.23 1.22 1.22 1.22 1.22 1.21 1.21 1.21 1.21 1.21 1.21 1.20 1.20 1.20 1.20
Mn mg/L -- 0.05t 0.77 0.76 0.76 0.76 0.76 0.76 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.74 0.74
Mo mg/L -- -- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
Na mg/L -- -- 7.8 7.8 7.8 7.8 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.6 7.6 7.6 7.6 7.6
Ni mg/L 0.07329* 0.1t 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
P mg/L -- -- <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
Pb mg/L 0.0039* 0.015t 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002
Sb mg/L -- 0.001 t 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
Se mg/L 0.0031§ 0.02t 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 <0.0001 <0.0001 <0.0001
Si mg/L -- -- 8.91 8.88 8.86 8.84 8.82 8.80 8.78 8.76 8.75 8.73 8.72 8.71 8.70 8.69 8.68 8.67
Sn mg/L -- -- <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04
SO4 mg/L -- 250 2.40 2.41 2.42 2.42 2.43 2.43 2.43 2.43 2.43 2.43 2.43 2.42 2.42 2.42 2.41 2.41
Sr mg/L -- -- 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02
TI mg/L -- 0.002t 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 1 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004
U mg/L -- -- 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
V mg/L -- -- 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
Zn mg/L 0.16522* 1 t 1 0.02 1 0.02 0.02 0.02 0.02 1 0.02 1 0.02 0.02 0.02 0.02 1 0.02 1 0.02 0.02 0.02 0.02 0.02
NO3 mg/L as NO3 -- 44.3 0.10 0.10 0.10 0.10 0.10 1 0.10 0.10 0.10 0.10 0.10 0.11 0.11 1 0.11 0.11 1 0.11 0.11
TDS(calc) mg/L -- 500 50.8 50.7 50.6 50.5 50.4 1 50.3 50.3 50.2 50.1 50.1 50.0 50.0 1 49.9 1 49.9 1 49.8 49.8
0.01 Indicates predicted concentration is greater than North Carolina surface water quality standard
0.01 Indicates predicted concentration is greater than North Carolina groundwater standard
Values are presented for dissolved metal concentrations unless otherwise noted
1 North Carolina DEQ Water Quality Standards for Class C Waters.The most stringent value of the acute/chronic standard is used
*Hardness dependent criteria.Standards were calculated using a default hardness value of 150 mg/L,which represents the 25th percentile of available data from the onsite weir
**No NC DEQ standard for alkalinity. Uses EPA NRWQC Freshwater Class C Standard
§Lotic standard
t Represents total recoverable metal concentration