NC0090212_plan of action_20230215

Consulting (U.S.), Inc.
srk consulting
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Technical Memo
February 15, 2023
To Adam Parr, Mining Director, North Carolina Department of Environmental Quality, Division of Energy,
Minerals, and Land Resources
From Ruth Griffiths, Amy Prestia, Rob Bowell
Cc David Miller (DEQ), Toby Vinson (DEQ), Morgan Warren (Albemarle Corporation)
Subject Kings Mountain Geochemical Characterization Work Plan
Client Albemarle Corporation
Project Kings Mountain Project
1 Introduction
The following work plan has been prepared by SRK Consulting (U.S.), Inc. (SRK) on behalf of
Albemarle Corporation (Albemarle) to provide the North Carolina Department of Environmental Quality
Division of Energy, Minerals and Land Resources (DEQ) with a description of the approach and test
methods being used for the geochemical characterization of waste rock, ore and tailings at the Kings
Mountain Project located in North Carolina.
1.1 Objectives
The primary purpose of this investigation is to provide an understanding of the geochemical
characteristics of geological materials specific to the Kings Mountain Project and to define the potential
for future mining wastes, including tailings, waste rock and pit wall rock, to generate acid or leach
deleterious constituents. In order to accomplish the objectives of the study, representative samples
have been collected and characterized following guidelines set forth in the Global Acid Rock Drainage
(GARD) Guide (INAP, 2014), the MEND Prediction Manual for Drainage Chemistry from Sulfidic
Geologic Materials (MEND, 2009) and the Bureau of Land Management Instruction Memorandum NV-
2010-014, Nevada Bureau of Land Management Rock Characterization Resources and Water Analysis
Guidance for Mining Activities (BLM, 2013). These are internationally recognized guidance documents
for the geochemical characterization of geological materials and are derived from best practices of the
mining industry, government, academia and community groups conducting mine site drainage
chemistry predictions.
Recognizing that the work performed as part of the geochemical characterization study will be
integrated into the subsequent permitting documents prepared for the site, SRK developed an
approach for a purpose-built characterization that focuses on the following aspects:
Assessment of waste rock geochemistry to provide a prediction of the potential geochemical
reactivity and stability of future waste rock and construction material for the project, and to
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Kings Mountain Geochemical Characterization Work Plan
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determine potential contact water (run-off and seepage) chemistry associated with the future mine
facilities.
Evaluation of tailings material geochemistry to provide a prediction of contact water chemistry that
may change over time and would influence the design, operation and closure of the Tailings
Storage Facility (TSF).
Determination of final pit wall geochemistry to define the control that the pit wall rocks would have
on the chemistry of waters removed from the pit during operation and pit lake that will form after
closure.
The results of the geochemical characterization testwork will provide a basis for the assessment for
Acid Rock Drainage and Metal Leaching (ARDML) and will support predictions of future contact water
quality (i.e., runoff and groundwater that contacts waste rock or pit walls). In turn, these results will be
used to inform decisions on engineering designs, mine planning and waste rock and tailings
management.
The purpose of this memorandum is to provide a detailed description of the geochemical
characterization program design, in particular the Leaching Environmental Assessment Framework
(LEAF) test methodology, and to obtain approval from DEQ on the approach and scope of the
program. This memorandum includes a summary of the static test data available to date that supports
the design of the LEAF and kinetic test programs and elaborates on the information provided by SRK
in the October 6, 2022 meeting with DEQ. Full details of the characterization program methodology
and results will be presented in a comprehensive geochemical characterization report.
2 Background
2.1 Project Location
The Kings Mountain Project is located in southwestern North Carolina, USA, adjacent to the city of
Kings Mountain on the 1-85 transit corridor, approximately 33 miles west of the city of Charlotte (Figure
2-1). The Property is located at approximately 35 degrees, 13 minutes north latitude and 81 degrees,
21 minutes west longitude.
2.2 Project Climate
South -Central North Carolina is situated in a humid subtropical climate (Cfa) per the Koppen climate
classification system. This climate is generally characterized by hot humid precipitous summers and
cold drier winters. Average winter temperatures vary between 30 degrees Fahrenheit (°F) to 50°F.
Average summer temperatures vary between 70OF to 90°F.
Average monthly precipitation varies between 3 inches 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. South -Central North Carolina is prone to thunderstorms during the summer and ice storms
during the winter.
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Kings Mountain Geochemical Characterization Work Plan
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2.3 Geology and Mineralization
As described by SRK (2021), North Carolina's tin-spodumene belt lies within the Inner Piedmont
terrane, an orogenic core formed during the Devonian -Mississippian, Acadian-Neoacadian orogeny of
the southern Appalachians. The Inner Piedmont stretches for some 700 kilometers (km) strike length
from Winston-Salem in North Carolina to the Coastal Plain in Alabama, bound between the Brevard
Fault Zone (BFZ) to the northwest and the Central Piedmont Suture (CPS) to the southeast (Merschat
et al., 2012). Rocks of the Eastern Inner Piedmont, the Cat Square terrane, are unconformably abutted
against the exotic peri-Gondwanan Carolina super terrane along the CPS; spodumene pegmatites,
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Kings Mountain Geochemical Characterization Work Plan
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hosted by rocks of the Cat Square terrane, occur along a reactivation of this major tectonic boundary,
the Kings Mountain shear zone (KMSZ).
In the Kings Mountain area, the Cat Square terrane is composed of amphibolites, mica schist, and
mica gneiss; these are interpreted to represent the deposition of pelitic sediments, with subsequent
mafic and ultramafic intrusions, in the remnant Iapetus Ocean basin that existed between Laurentia
and the Carolina superterrane. Mississipian aged Cherryville Granite, granite pegmatite, and
spodumene pegmatites intrude the mica schist and amphibolite units of the Cat Square terrane along
the KMSZ. Spodumene pegmatites, averaging up to 20% spodumene, vary in thickness and overall
extent; hundreds of these spodumene pegmatite dikes occur in the Kings Mountain area, with most
less than 10 feet (ft) thick while the largest spodumene pegmatite dikes are approximately 400 ft thick
and 3,300 ft long.
The Kings Mountain deposit is a Lithium -bearing rare -metal pegmatite intrusion that has penetrated
along the KMSZ. The pegmatite field at Kings Mountain is approximately 1,500 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 lithium mineralization at the Kings Mountain deposit occurs within albite-
spodumene pegmatites and to a lesser extent within metamorphosed altered wallrock adjacent to
mineralized pegmatites. A generalized stratigraphic column is provided in Figure 2-2.
No
•L L. O
N O upper mica Schist N■
(upper mica sch)
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O C
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1 U phyllite (phyllite)
Figure 2-2: Generalized Stratigraphic Column
■
SRK CONSULTING (U.S.), INC. ■ FEBRUARY 15, 2023

Kings Mountain Geochemical Characterization Work Plan
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A detailed geological model has been developed by Albemarle and various consultants as part of the
exploration program and to provide information for mine planning purposes. A plan view and cross -
sectional view of the geologic model from SRK (2021) is provided in Figure 2-3 and Figure 2-4.
Development of this geological model is ongoing, and the geologic interpretations are subject to
change.
A total of twelve material types have been identified for the purposes of the Kings Mountain
geochemical characterization program based on lithology and grade (i.e., ore versus waste). The Kings
Mountain material types are summarized in Table 2-1 along with the estimated proportions to be mined
based on the current mine plan and geologic model. The material type proportions in Table 2-1 may
change as the geologic interpretation of the deposit evolves, and the geologic model is updated.
Table 2-1: Kings Mountain Geochemical Program Material Types
Category Main Material Type
Estimated Percentage
of Total to be Mined'
Waste Rock Overburden
1.3%
Amphibolite Gneiss -Schist
45.5%
Biotite Gneiss
3.2%
Mica Schist
10%
Pyrrhotite (Po) Mica Schist
5%
Upper Mica Schist
6.2%
Shear Schist
4.2%
Silica Mica Schist
3.7%
Diabase
<1 %
Granite
<1 %
Ore Pegmatite
0.9%
Spodumene Pegmatite
19.3%
'Proportions are an estimate and subject to change based on ongoing modeling and mine planning.
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Kings Mountain Geochemical Characterization Work Plan
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Figure 2-3: Geologic Model Plan View
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Kings Mountain Geochemical Characterization Work Plan
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0
Figure 2-4: Geologic Model Cross -Sectional View
A'
Full —Rock —Name—
Merged_2018
■ Amphibole Gneiss -Schist
■ Amphibolite
. Aplite
- Chlorite Schist
■ Diabase
Granite
Mafic
■ Marble
Mica Schist
■ Musc Peg
■ NR
s ■ Overburden
7 Peg
phyllite
1 .
Quartzolite
■ Schist - Marble
Shear Schist
■ Silica Mica Schist
ANN*■ Spod Peg
Upper Mica Schist
,fA ■ Water
suo
Plunge 00
Azimuth 015
0 100 200 300
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Kings Mountain Geochemical Characterization Work Plan
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3 Mine Plan, Conceptual Model and Program Design
A conceptual geochemical model has been developed based on the deposit geology combined with
the proposed mining and processing methods. This conceptual model provides the basis for the scope
and methodology of the geochemistry baseline study and defines the approach for sample selection,
laboratory procedures and key criteria for decision -making throughout the process.
The Project will be developed as an expansion of a previously mined open pit. The Albemarle owned
site has an existing lithium conversion plant and research/administrative facility. The primary project
includes redevelopment of the open pit, spodumene concentrator and associated infrastructure, and
construction of waste rock/tailings storage facilities.
Ore and waste rock will be mined using conventional open pit mining techniques including drill and
blast, loading and truck haulage. Mining will take place below the regional water table and the pit will
be flooded upon closure of the mine. Waste rock will be generated from mining and placed in waste
rock storage facilities. Potentially acid generating (PAG) waste rock mined from the pit will be managed
to mitigate risks to the environment. The operation will employ dry stack tailings technologies to reduce
the amount of water required in the mining process, improve the stability of the TSF, and minimize the
overall footprint of the operation. Dry stack tailings technology removes most of the moisture from the
tailings slurry mixture.
The design of the geochemical characterization program has been developed based on the geology of
the site and the mine plan information. Table 3-1 provides a list of the mine materials that will require
geochemical characterization and the types of geochemical data required. Because Albemarle is
currently evaluating variations within the mineral processing flow sheet including ore sorting, magnetic
separations, and dense media separation (DMS), the specific type of waste produced may change.
The potential waste streams that will be generated from the lithium extraction process are summarized
in Table 3-1; however, the waste streams and management of these waste streams may change as
the ongoing metallurgical testing program and the flow sheet are finalized.
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Table 3-1: Program Design
Mine Component/ Location Duration Composition Material Geochemical Characterization Test Methods
Facility Available for
Characterization
ABA, Mineralogy EPA LEAF HCT
NAG, 1312
ICP (SPLP)
EPA 1313 EPA 1314 EPA 1315 EPA 1316
(pH) (Upflow) (Diffusion) (L/S)
Waste rock Mine area Permanent Non-PAG and PAG Core' X X X X X X
storage facilities Waste rock
Sonic core X -- X
Ore sorting rejects Met program3 X X X X X X
DMS material Met program3 X X X X X
Material from magnetic Met program3 X X X
separation
Ore stockpiles Plant site Temporary Ore grade material Core' X X X X X
Pit walls Open pit Permanent Waste rock and low- Core' X X X X X X
grade ore
Pit backfill Open pit Permanent Non-PAG and PAG Core' X X X X X X X
Waste rock
Sonic core X -- X
Dry stack TSF Mine area Permanent Flotation tails Met program3 X X X X X X X
Sonic core' X -- X
Reclamation Various Permanent Soil for reclamation Sonic core X -- X
covers (pre -strip)
Borrow areas Various Permanent Non-PAG waste rock Core' X -- X X
for construction
material
' Core from exploration drillholes throughout the deposit (unweathered)
2 Sonic core from legacy facilities (weathered)
3 Residues from metallurgical testwork programs
° Sonic core from holes drilled into alluvium within mine facility footprints
Note: The ore processing flow sheet is still under development and the information in this table may change as the details are finalized
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023
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Kings Mountain Geochemical Characterization Work Plan
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4 Waste Rock Characterization
4.1 Waste Rock and Ore Sample Collection
Sample selection is a fundamental step in any geochemical characterization program. The number of
samples selected for testing is typically based on the number of discrete material types identified for a
deposit as well as the relative percentage of each material type predicted to be mined according to the
geologic model. For the Kings Mountain geochemical characterization program, material types have
been delineated based on lithology and grade (i.e., ore vs. waste) as described above.
A total of 474 samples representative of future waste rock and ore have been collected from
exploration drill core for geochemical characterization testing. The samples are summarized in Table
4-1 and are shown in the context of the future pit in Figure 4-1. The material type proportions in Table
4-1 may change as the geologic interpretation of the deposit evolves, and the geologic model is
updated. However, the number and location of samples is still considered representative and adequate
to characterize the material associated with the Project and predict water quality for the future mine
facilities.
In addition, samples of waste rock are being collected from existing (legacy) waste rock piles from
previous operations. The purpose of these samples is to compare the geochemistry of fresh rock (i.e.,
core) to weathered rock material that has been exposed to oxygen and water for over 50 years. This
will provide an indication of the soluble weathering products that developed as a result of weathering
that are available for leaching from this material. An estimated 20 to 40 samples of legacy waste will be
collected during the ongoing drill program.
4.2 Waste Rock and Ore Characterization Test Methods
The geochemical test methods selected for this Project include both static and kinetic testing that are
designed to address the bulk geochemical characteristics of the samples, and to assess the potential
of waste rock and ore materials to generate acid or release metals into solution. "Static testing" is a
general term describing those analytical methods applied to characterize acid generation and metal
leaching characteristics of material at the time of testing and does not account for temporal changes
that may occur in the material as chemical weathering proceeds. Static tests provide a balance of acid
generating and acid consuming reactions at an end point and may be used to determine the potential
magnitude of metals leaching from a given material.
Static testing is distinguished from "kinetic tests", which evaluate the rate of sulfide oxidation and metal
release over time. Static testing provides a conservative approximation of acid generation and trace
metal release potential, which is used to determine whether more comprehensive kinetic testing is
warranted. Based on the results of the static tests, materials that exhibit uncertain or highly variable
geochemical behavior may require further characterization using kinetic test methods to determine the
rates and character of longer -term leaching.
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Kings Mountain Geochemical Characterization Work Plan
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The geochemical test methods for the Kings Mountain Project have been selected to determine the
total acid generating or neutralizing potential of the samples and assess the concentration of
constituents in leachates that could be derived from the material. Static and kinetic testing
methodologies include the following:
Multi -element analysis using four -acid digestion followed by Inductively Coupled Plasma Mass
Spectroscopy (ICP-MS) or ICP Atomic Emission Spectroscopy analysis (ICP-AES) to determine
total chemistry for 48 elements plus mercury (ALS Chemex Method ME-MS61 m)
Measurements of paste pH
Acid Base Accounting (ABA) using the modified Sobek method (Sobek et al., 1978) with sulfur
speciation by hydrochloric acid and nitric acid extraction
Net Acid Generating (NAG) testing that reports the final NAG pH and final NAG value after a two -
stage hydrogen peroxide (H2O2) digest (Miller et al., 1997)
Synthetic Precipitation Leaching Procedure (SPLP) testing (US EPA, 1994) and analysis of
leachate
Leaching Environmental Assessment Framework (LEAF) testing using the EPA 1313, 1314 and
1316 methodologies (US EPA, 2012a;b; US EPA, 2017a)
Humidity Cell Test (HCT) Procedure (ASTM D5744-96), including analysis of extracts
Mineralogical analysis, including optical microscopy, Scanning Electron Microscopy (SEM), X-Ray
Diffraction (XRD), QEMSCAN and TIMA.
A sample matrix summarizing the number of waste rock and ore samples submitted for each test is
provided in Table 4-1 and full details of the test methods are provided in the following sections. At the
time of writing, the ABA, NAG and multi -element analysis is complete, and the SPLP, LEAF, HCT and
mineralogy work is in progress.
Samples collected from the legacy waste rock and ore piles onsite will be submitted for ABA, NAG and
multi -element analysis. Based on the results of this testing, a sub -set of samples will be selected for
mineralogy, SPLP and LEAF testing.
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Kings Mountain Geochemical Characterization Work Plan
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Table 4-1: Waste Rock and Ore Sample Frequency and Testing Matrix
Category Main Material Type Estimated
ABA/NAG/
HCT/
Modified
LEAF EPA
Percentage
Multi-
Mineralogy
SPLP, LEAF
1314
of Total to be
Element
(optical,
(EPA 1313
(in
Mined
(complete)
SEM, XRD)
and 1316),
progress)
(in
Mineralogy
progress)
(XRD)
(in progress)
Waste Overburden
1.3%
5
1
0
0
Rock Amphibolite Gneiss -Schist
45.5%
116
5
4
2
Biotite Gneiss
3.2%
31
2
3
1
Mica Schist
10%
44
3
3
2
Pyrrhotite (Po) Mica Schist
5%
39
2
2
1
Upper Mica Schist
6.2%
12
2
1
1
Shear Schist
4.2%
49
3
4
2
Silica Mica Schist
3.7%
8
1
1
1
Diabase
<1 %
2
0
0
0
Granite
<1%
2
0
0
0
Ore Pegmatite
0.9%
109
2
3
0
Spodumene Pegmatite
19.3%
57
1
2
0
Total
474
22
23
10
Figure 4-1: Geochemical Characterization Samples in Context of Final Pit Shell
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Kings Mountain Geochemical Characterization Work Plan
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4.2.1 Static Testing
Acid Base Accounting
ABA provides an industry -recognized assessment of the acid generation or acid neutralization potential
of rock materials. It indicates the theoretical potential for a given material to produce net acid
conditions. The technique characterizes the `total potential reservoir of acidity or alkalinity in a given
material' but does not account for mineralogy, kinetics or other influencing factors controlling natural
sulfide oxidation.
The ABA method used for the Kings Mountain Project is the Modified Sobek ABA method (Sobek et
al., 1978), which includes both laboratory analysis and empirical calculations based on acid potential
(AP) and neutralizing potential (NP). An estimate of acid generation is made by assuming complete
reaction between all of the minerals with acid potential and all of the minerals with neutralizing potential
(essentially dissolution of carbonate minerals and to some extent silicate minerals). The AP values
were calculated from sulfide sulfur concentrations and reported as kilograms of calcium carbonate per
ton of rock (kg CaCO3 eq/t). The NP values were determined using the Modified Sobek protocol that
includes a digestion to expel any CO2 followed by a back titration with NaOH to pH 8.3. Neutralizing
potential is calculated as CaCO3 equivalents per ton of rock. The samples were also submitted for
determination of total inorganic carbon (TIC) by Leco analysis to provide a second measure of
neutralization potential for comparison. Measurements of paste pH are also taken and provide an
indication of the availability of the acid neutralizing minerals for buffering
The balance between the acid generating mineral phases and acid neutralizing mineral phases is
referred to as the net neutralization potential (NNP), which is equal to the difference between NP and
AP. The NNP allows classification of the samples as potentially acid consuming or acid producing. A
positive value of NNP indicates the sample neutralizes more acid than is produced during oxidation. A
negative NNP value indicates there are more acid producing constituents than acid neutralizing
constituents. Material that would be considered to have a high potential for acid neutralization
produces a net neutralizing potential greater than 20 kg CaCO3/t. Those materials considered to have
a higher potential for acid generation produce an NNP less than -20 kg CaCO3/t.
ABA data are also assessed using the neutralization potential ratio (NPR), which is calculated by
dividing the NP by the AP. NPR values less than 1 indicate a higher potential for acid generation and
greater than 3 indicate significant acid neutralization. For the purposes of the King Mountain
characterization program, a site -specific NPR cut-off will be developed for identifying potentially acid
generating material. This site -specific cut-off will be defined based upon the results of the
characterization program described herein.
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Kings Mountain Geochemical Characterization Work Plan
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Net Acid Generation Testing
Static Net Acid Generation (NAG) testing is being used as a second measure of ARID potential for the
Kings Mountain waste rock and ore samples. The static NAG test differs from the ABA test in that it
provides a direct empirical estimate of the overall sample reactivity, including any acid generated by
semi -soluble sulfate minerals as well as potentially acid -generating sulfide minerals. NAG testing was
carried out in accordance with the method described by Miller et al. (1997). The method essentially
involves intensive oxidation of the sample using hydrogen peroxide, which accelerates the dissolution
of sulfide minerals and has the net result that acid production and neutralization can be measured
directly. The leachate is then titrated with sodium hydroxide in two stages (to pH 4.5 and to pH 7) to
determine the NAG value, which is calculated as follows:
NAG = (Vi it / X) (49 * VNaOH * M) / W
Where:
NAG = net acid generation (kg H2SO4 per metric ton)
Vtnit = volume of initial hydrogen peroxide solution (mQ
X = volume used to determine NAG by titration (mL)
VNaOH = volume of NaOH used in titration (mQ
M = concentration of NaOH used in titration (moles/liter)
W = weight of sample reacted (g)
Based on the NAG method, the criteria used for assessing the acid generation potential based on NAG
results are summarized in Table 4-2. In general, a NAG pH greater than pH 4 and a NAG value equal
to zero are indicative of a non-acid generating material. A NAG value greater than one kg H2SO4/t
indicates the sample would generate some acidity in excess of available alkalinity. However, by
convention, any NAG value below 10 kg H2SO4/t has a limited potential for acid generation and the
results are considered inconclusive because a blank hydrogen peroxide solution can generate a NAG
artifact value up to 10 kg H2SO4/t (Sapsford et al., 2009).
Table 4-2: Acid Generation Criteria for NAG Test Results
Acid Generation Capacity Final NAG
NAG value
pH (s.u.)
(kg H2SO4 eglt)
Potentially Acid Higher Capacity < 4.5
>10
Generating (PAG)
Lower Capacity < 4.5
<10, >1
Non -Acid Generating (non-PAG) > 4.5 0
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Kings Mountain Geochemical Characterization Work Plan
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Multi -Element Analysis
The Kings Mountain waste rock and ore samples have been submitted for multi -element analysis using
the ME-MS61 m method that involves a four -acid digest followed by ICP-MS/ICP-AES analysis to
determine total concentrations for 48 elements plus mercury. The four -acid digest is able to dissolve
most minerals in the sample matrix and provides near -total quantitative results.
Multi -element analysis is a useful screening -level tool for geochemical characterization and the data
can be used to evaluate the variation in chemical composition across the deposit or fingerprint different
lithologies. When compared to average elemental crustal abundance, multi -element data can also
provide an indication of elemental enrichment that may be of environmental importance and can
identify parameters that might be of concern for the Project. The soluble or leachable portion of these
elements, however, needs to be estimated empirically by leach tests (i.e., SPLP, LEAF or HCT
testing), which account for site -specific factors that affect mineral solubility.
The results of the multi -element analysis are analyzed using the Geochemical Abundance Index (GAI;
]NAP, 2014), which compares the concentration of an element in a given sample to its average crustal
abundance. GAI values are particularly useful in determining the relative enrichment of elements
based on lithology and may be used to identify elements enriched above average crustal
concentrations.
GAI values are calculated as follows:
GAI =1og2 [C/(1.5*S)]
Where C is the concentration of an element as determined from the multi -element assay, and S is the
average crustal abundance of the element of interest (Mason, 1966). Materials are then assigned a
GAI value between zero and six based on the degree of enrichment (Table 4-3). According to the INAP
(2014) protocol, a GAI value greater than three indicates significant enrichment.
Table 4-3: Interpretation of GAI Values
GAI Value
Interpretation
0
< 3 times average crustal concentrations
1
3 to 6 times average crustal concentrations
2
6 to 12 times average crustal concentrations
3
12 to 24 times average crustal concentrations
4
24 to 48 times average crustal concentrations
5
48 to 96 times average crustal concentrations
6
>96 times average crustal concentrations
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Kings Mountain Geochemical Characterization Work Plan
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4.2.2 Short-term Leach Testing
Synthetic Precipitation Leaching Procedure (SPLP)
The Synthetic Precipitation Leaching Procedure (EPA Method 1312) is being conducted on
representative composite samples to evaluate the short-term reactivity of waste rock and ore materials
associated with the Kings Mountain Project. The SPLP method is an agitated extraction method that
requires particle size reduction to less than 9.5 mm. The standard SPLP method uses an extraction
solution that has been adjusted with dilute sulfuric/nitric acid to pH 5.0 and is typically run at a 20:1
solution to solid ratio. The high liquid to solid ratio may result in an underestimate of leachability and
grain size reduction may increase reactivity.
For the Kings Mountain characterization program, a modified SPLP method is being used where the
extraction solution consists of D.I. water with no pH adjustment and the solution to solid ratio is 2:1.
Due to these modifications, the results of the modified SPLP are more comparable to the Nevada
Meteoric Water Mobility Procedure (MWMP) that is frequently used to provide a measure of the readily
soluble constituents of mine waste. The results of the SPLP provide a qualitative evaluation of
constituents that could occur at concentrations above the water quality criteria (i.e., concentrations are
not considered to be conclusive or to represent actual predictions of water quality).
SPLP testing is being conducted on 23 composite samples representative of the main Kings Mountain
material types in Table 4-1. In addition to SPLP testing, these composites have also been submitted
for LEAF testing as described in Section 4.2.2 below. Composite samples were generated from the
core samples to capture the range of static test results (ABA and NAG) for each of the main material
types. The sub -samples selected for each of the composites contain similar sulfide sulfur content and
demonstrate similar ABA and NAG characteristics. For example, four composites were generated for
the Amphibolite Gneiss -Schist material as shown in Figure 4-2 through 4-5.
Also shown are the discrete samples selected for kinetic testing as described in Section 4.2.3. Graphs
showing the sub -samples included in the composites for the remaining material types are provided in
Attachment 1. Composites were not generated for the overburden (alluvium), granite or diabase
material types because these material types comprise an insignificant portion (<1.5%) of the waste
rock material.
SPLP extracts were submitted for the list of analytes and associated reporting/detection limits in Table
4-4. Radiochemistry was not completed for one sample of pegmatite due to limited sample material.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 16

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
NP vs. AP
1000
Non-PAG
100 O
. ' -
cn
8
♦
000
Amphibole Gneiss -Schist
g
O
-
004-•'
----
NPR =1
NPR =2
U 10
$ O
O
®
O
HCis
m
�e O
O
8 O
O
O
Comp 1*
z
O
Comp 2
O
Comp
PAG
O
Comp 4
1
' Selected
for EPA 1314
0.1
0.10
1.00
10.00
100.00
AP (kg CaCO3/t)
Figure 4-2: Neutralization Potential versus Acidification Potential
NAG pH vs. NPR
12
11
N r.-
•♦-���4♦o
10
r'
OO
O O O 00 O 0
9
cc
CL
Z
O O O
00
0 0
8
00
lia—
O O o
♦
Amphibole Gneiss -Schist
2
0 O O 0
00
NPR=2
x
o 0
1 0
- -
NAG pH=4.5
a 6
* * #
O
HCTs
z
g o A
O
Comp 1*
5
NAG pH = 4.5
O
Comp 2 *
O
Comp
4
Q'
O
O
Comp 4
3
�
o
* Selected for EPA 1314
2
1
0.00
0.01 0.10 1.00 10.00 100.00 1000.00
Neutralization Potential Ratio
Figure 4-3: Neutralization Potential Ratio versus NAG pH
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 17

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
NAG vs. NAG pH
60
PAG
1 Non-PAG
50
1
1
0
1
<, 40
1
O
`^
x
1
co
c
1
30
12
c
�
1
v
C7
1
a
Q 20
1
w
1
z
•
10
1
I ••
��
i�
o
�Y �i B �•rr� �• •� ■ulllijb
0 2 4
6 8 10 12
NAG pH (s.u.)
Figure 4-4: NAG pH versus Net Acid Generation
NAG pH vs. Sulfide (wt %)
12
11 • ♦ ♦ �• i
10
9 ♦ ♦ ♦♦
8
7 ?: ♦ O
a 6 i . . ♦ . O❑♦ Z
7
Q
Z ♦ ❑♦
5
AG pH = 4.5
----------- �♦�-♦♦------------
4 ❑♦
Epic *
3 ♦
2
1
0.001 0.01 0.1 1 10
Sulfide Sulfur (wt %)
Figure 4-5: Sulfide Sulfur versus NAG pH
•
Amphibole Gneiss -Schist
O
HCTs
— —
NAG pH=4.5
O
Comp 1
O
Comp 2
O
Comp 3
O
Comp 4
Selected for EPA 1314
♦ Amphibole Gneiss -Schist
O HCTs
— — NAG pH = 4.5
O Comp *
O Comp2 *
O Comp3
O Comp4
* Selected for EPA 1314
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 18

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
Table 4-4: List of Analytes and Detection Limits for Leach Tests
Parameter
Parameter Description
Laboratory Method
Laboratory Detection
Limit
pH
Hydrogen ion concentration
M9045D/M9040C
-
Conductivity
Electrical conductivity
SM2510B
2 pmhos/cm
Alkalinity as CaCO3
General inorganic
SM2320B - Titration
2 mg/L
Bicarbonate as CaCO3
General inorganic
SM2320B - Titration
2 mg/L
Carbonate as CaCO3
General inorganic
SM2320B - Titration
2 mg/L
Hydroxide as CaCO3
General inorganic
SM2320B - Titration
2 mg/L
Aluminum
Dissolved metals, filtered in lab
M6010D ICP
0.05 mg/L
Antimony
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.0004 mg/L
Arsenic
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.0002 mg/L
Barium
Dissolved metals (filtered in lab)
M6010D ICP
0.009 mg/L
Beryllium
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.00008 mg/L
Bismuth
Dissolved metals, filtered in lab
M6010D ICP
0.04 mg/L
Boron
Dissolved metals, filtered in lab
M6010D ICP
0.03 mg/L
Cadmium
Dissolved metals, filtered in lab
M6020B ICP-MS
0.00005 mg/L
Calcium
Dissolved metals, filtered in lab
M6010D ICP
0.1 mg/L
Carbon, total
General inorganic
SM5310B
1 mg/L
Carbon, total inorganic
General inorganic
SM5310B
1 mg/L
Carbon, total organic
General inorganic
SM5310B
1 mg/L
Chloride
General inorganic
SM4500CI-E
1 mg/L
Chromium
Dissolved metals, filtered in lab
M6010D ICP
0.02 mg/L
Cobalt
Dissolved metals, filtered in lab
M6010D ICP
0.02 mg/L
Copper
Dissolved metals, filtered in lab
M6010D ICP
0.01 mg/L
Fluoride
General inorganic
SM4500E-C
0.15 mg/L
Gross alpha & beta, total
Radiochemistry
WG551392
2 to 4 pCi/L
Iron
Dissolved metals (filtered in lab)
M6010D ICP
0.06 mg/L
Lead
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.0001 mg/L
Lithium
Dissolved metals, filtered in lab
M6010D ICP
0.008 mg/L
Magnesium
Dissolved metals, filtered in lab
M6010D ICP
0.2 mg/L
Manganese
Dissolved metals, filtered in lab
M6010D ICP
0.01 mg/L
Mercury
Dissolved metals (filtered in lab)
M1631E, Atomic Fluorescence
0.0000003 mg/L
Molybdenum
Dissolved metals, filtered in lab
M6010D ICP
0.02 mg/L
Nickel
Dissolved metals, filtered in lab
M6010D ICP
0.008 mg/L
Nitrate/Nitrite as N
General inorganic
M353.2
0.02 mg/L
Phosphorus
Dissolved metals, filtered in lab
M6010D ICP
0.1 mg/L
Potassium
Dissolved metals, filtered in lab
M6010D ICP
0.2 mg/L
Radium 226 + alpha
emitting radium isotopes
WG551336
WG551336
1 pCi.L
Radium 228, total
Radiochemistry
WG551336
1.5 pCi/L
Scandium
Dissolved metals, filtered in lab
M6010D ICP
0.05 mg/L
Selenium
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.0001 mg/L
Silicon
Dissolved metals, filtered in lab
M6010D ICP
0.1 mg/L
Silver
Dissolved metals (filtered in lab)
M6010D ICP
0.01 mg/L
Sodium
Dissolved metals, filtered in lab
M6010D ICP
0.2 mg/L
Strontium
Dissolved metals, filtered in lab
M6010D ICP
0.009 mg/L
Sulfate
General inorganic
D516--07 - TURBIDIMETRIC
1 mg/L
Sulfur
Dissolved metals, filtered in lab
M6010D ICP
0.25 mg/L
Thallium
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.0001 mg/L
Thorium
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.001 mg/L
Tin
Dissolved metals, filtered in lab
M6010D ICP
0.04 mg/L
Titanium
Dissolved metals, filtered in lab
M6010D ICP
0.005 mg/L
Total dissolved solids
General inorganic
SM2540C
20 mg/L
Uranium
Dissolved metals (filtered in lab)
M6020B ICP-MS
0.0001 mg/L
Vanadium
Dissolved metals, filtered in lab
M6010D ICP
0.01 mg/L
Zinc Dissolved metals (filtered in lab) M6010D ICP 0.02 mq/L
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 19

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
Environmental Assessment Framework (LEAF) Testing
The Leaching Environmental Assessment Framework (LEAF) is a leaching evaluation protocol that
consists of four leaching methods, data management tools, and scenario assessment approaches
designed to work individually or to be integrated to provide a description of the release of inorganic
constituents of potential concern (COPCs) for a wide range of solid materials (US, EPA, 2022). The
LEAF methods were originally developed in the European Union (EU) for evaluating coal combustion
products and are designed to consider the effect of key environmental conditions and waste properties
on leaching.
The application of LEAF methods to mining evaluations is relatively new, but they are typically used
when conventional static and kinetic test methods do not adequately describe potential chemical
releases. To date, they have primarily been used in the assessment of constituent leaching from
cemented backfill in underground mines (Schafer, 2016). For the Kings Mountain characterization
program, the LEAF tests are being done to provide additional information on the leachability of the
waste rock and ore material and provide the most comprehensive characterization of this material as
possible.
Each of the following leach tests is designed to vary a critical release -controlling parameter to provide
leaching data over a range of test conditions:
Method 1313: Liquid -Solid Partitioning as a Function of Eluate pH Using a Parallel Batch Extraction
Procedure (US EPA, 2012a)
Method 1314: Liquid -Solid Partitioning as a Function of Liquid -to -Solid Ratio Using an Up -Flow
Percolation Column Procedure (US EPA, 2017a)
Method 1315: Mass Transfer Rates in Monolithic and Compacted Granular Materials Using a
Semi -dynamic Tank Leaching Procedure (US EPA, 2017b)
Method 1316: Liquid -Solid Partitioning as a Function of Liquid -to -Solid Ratio Using a Parallel Batch
Extraction Procedure (US EPA, 2012b)
Three of these LEAF methods are proposed as being applicable for the Kings Mountain waste rock
and ore geochemical characterization program these are; EPA 1313, EPA 1314 and EPA 1316.
The EPA 1313 method is designed to evaluate the partitioning of constituents between liquid and solid
phases at or near equilibrium conditions over a wide range of pH values (pH 2 to 12). The method
consists of a series of parallel batch extractions of solid material at various target pH values, achieved
with an aliquot of either dilute acid or base. Testing is undertaken on a pulverized sample at a fixed L/S
ratio and produces a liquid -solid portioning curve of constituents as a function of pH.
The EPA 1314 method is a column percolation test designed to evaluate constituent release from solid
materials as a function of cumulative liquid -to -solid ratios (L/S). The method provides an estimate of
porewater concentrations at low L/S and allows determination of the changes in liquid -solid partitioning
as soluble constituents are released during successive pore volumes. The method is applicable to low
oxygen conditions where rock is submerged, for example pit backfill.
The EPA 1316 method is an equilibrium -based leaching test intended to provide eluate solutions as a
function of the L/S ratio. This method consists of five parallel batch extractions in reagent water over a
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 20

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
range of liquid -to -solid ratios (2:1, 5:1, 10:1, 50:1 and 100:1). The method provides liquid -solid
partitioning at the natural pH of a solid material as a function of L/S.
LEAF testing using the EPA 1313 and 1316 methods are being conducted on the 23 composite
samples that represent the range of geochemical variability demonstrated by the main Kings Mountain
material types. These are the same composites used in the SPLP test described above. Graphs
showing the sub -samples included in the 23 composite samples are provided in Attachment 1.
Composites were not generated for the overburden (alluvium), granite or diabase material types
because these material types comprise an insignificant portion (<1.5%) of the waste rock material.
In addition, nine of the composites and one sample from the HCT program were selected for the EPA
1314 test to represent waste rock materials that would be submerged in the pit backfill after dewatering
stops and groundwater recovers. The composites and HCT sample selected for EPA 1314 are shown
in the figures provided in Attachment 1 and include:
Composite 1 - Amphibole Gneiss -Schist
Composite 2 - Amphibole Gneiss -Schist
Composite 1 - Biotite Gneiss
Composite 1 - Mica Schist
Composite 2 - Mica Schist
Composite 1 - Po Mica Schist
Composite 1 - Shear Schist
Composite 2 - Shear Schist
Composite 1 - Upper Mica Schist
HCT - Silica Mica Schist
The EPA 1313, 1314 and 1316 methods have been selected for this study because they are
considered the most applicable batch leach methods to assess constituent release from waste rock
under the environmental conditions of the site. The EPA 1315 method is not considered applicable to
this study because it is designed to assess leaching from monolithic materials (e.g., concrete or
cemented rock fill) rather than heterogeneous waste rock materials.
The selected list analytes and associated reporting/detection limits for the LEAF tests are the same as
used for the SPLP test as summarized in Table 4-4. The exception to this is that the radiochemistry for
the LEAF tests is limited to Gross Alpha and Beta. The extracts were not submitted for the full suite of
radiochemistry because of limited sample volume generated by the LEAF test. However, the full suite
of radiochemistry is being completed on the SPLP extracts.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 21

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
4.2.3 Kinetic Testing
Kinetic testing is recommended for the Kings Mountain Project in order to assess the long-term
weathering rates of sulfide and other metal bearing minerals, consumption of inherent neutralizing
capacity and to determine potential metal and metalloid leaching rates, particularly for those material
types that demonstrated an uncertain potential for acid generation in the static tests. Kinetic tests (e.g.,
laboratory humidity cell tests, "HCT's") evaluate temporal changes in leachate chemistry, through the
sequential leaching of the rock in a regular cycle of exposure to dry and wet air in a controlled
laboratory environment. These cycles simulate and accelerate the chemical weathering rates observed
under field conditions, using test conditions that are specifically designed to target oxidation of sulfide
minerals.
The goal of kinetic testing is to provide reaction rate data to support prediction of the leachate
chemistry that would likely develop during meteoric rinsing of waste rock storage facilities. Kinetic test
data can also be used to predict concentrations of constituents that would be released from pit wall
rock in response to meteoric rinsing and to develop a prediction of future pit lake water quality required
for permitting of the project.
The kinetic testing procedure selected for the Kings Mountain Project consists of the standard HCT
procedure designed to simulate water -rock interactions in order to predict the rate of sulfide mineral
oxidation and therefore acid generation and metals mobility (ASTM D5744-13e1) (ASTM, 2013). Under
ASTM methodology, the test is carried out on material sized to pass a 6.3mm (0.25 inch) Tyler screen.
The test follows a seven-day cycle during which air that is humidified and at a temperature of 250C is
introduced at the bottom of the column for three days of each cycle followed by three days of dry air.
On the seventh day, the sample is rinsed with distilled water and the extracted solution is collected for
analysis. Key parameters including pH, alkalinity, acidity, electrical conductivity, iron and sulfate are
measured on a weekly basis to provide intermediate reference points between full analyses that are
conducted less frequently. Analysis of major and trace element chemistry is carried out on a weekly
basis for the first four weeks of the test, after which the frequency of analysis is reduced to every fourth
week.
The selected list analytes and associated reporting/detection limits for the HCTs are the same as used
for the SPLP test as summarized in Table 4-4. Due to the limited sample volume generated during the
HCT, radium 228 and radium 226 + alpha emitting radium isotopes are being analyzed on composite
samples. A 100 mL split is collected every week over an eight -week period to provide the sample
volume needed for radiochemistry analysis..
Geochemical reactions and reaction rates monitored throughout the test include sulfide oxidation,
depletion of NP, secondary mineral precipitation, adsorption -desorption reactions and mineral
dissolution (INAP, 2014). Termination of the HCTs will be determined when the release rates of key
constituents such as pH, sulfate, acidity, alkalinity and iron as well as dissolved metals and metalloids
become relatively constant with time and there is no substantial change in the calculated release rate
(INAP, 2014).
Prior to termination of the HCTs, a memo summarizing the results and a request for approval to
terminate the cells will be submitted to DEQ. This memo will provide the rational basis for termination
and outline the methods proposed for termination testing. Humidity cells will not be terminated without
DEQ approval.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 22

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
Following termination of the leach portion of the HCTs, the material within the cells will be blended and
split for termination testing. Termination testing will include multi -element analysis, ABA, NAG and
mineralogical analysis on some of the test residues to define the mineralogical processes that occurred
as the materials were exposed to oxygen and water and aid in the interpretation of the evolution of the
leachate during the HCT.
Results from the static geochemical characterization tests (ABA, NAG and multi -element) were used to
select a sub -set of 22 samples representing the main waste rock and ore types for kinetic testing
(Table 4-1). The geochemical properties of these material based on the static test results are illustrated
in the scatter plots presented in Figure 4-6 through Figure 4-8. These graphs show the distribution of
the samples selected for kinetic testing in relation to the entire dataset. Additional graphs are provided
in Attachment 1 broken out for the main material types. These graphs show the samples selected for
kinetic testing are representative of the range of static test results. Sulfide sulfur, NPR, NNP, NAG and
NAG pH were the key parameters used for sample selection.
Unlike the samples selected for SPLP and LEAF testing, the samples selected for the HCTs consist of
a single sample selected from the static test program (i.e., are not composites of multiple samples).
The exception to this is the HCT sample to represent pegmatite, for which limited material was
available. For this HCT, a composite using two samples was generated to represent this material type.
The resulting HCT sample set is lithologically representative of the deposit and the number of kinetic
test samples selected for each material type is based on the relative importance or mass of the
lithological unit with respect to the total mass in the deposit. Samples of granite and diabase material
types were not selected for kinetic testing because these material types comprise an insignificant
portion (<1 %) of the waste rock material. Even though alluvium represents a small portion of the mined
waste rock (1.3%), a sample of this material type was selected for kinetic testing to provide source
term chemistry for alluvium that will be needed for the pit lake geochemical modeling.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 23

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
140
120
100
c,
v
O 80
u
m
u
s 60
a
Z 40
m
20
0
0 0
c
0
0 -20
v -40
Z
Z -60
-80
-100
0.01
NPR vs NNP
0.1 1 10
Neutralizing Potential Ratio (NPR)
■ Overburden
Non-PAG
O
*Amphibole Gneiss -
Schist
♦ Biotite Gneiss
A Mica Schist
♦ Upper Mica Schist
x
A Po Mica Schist
♦ Shear Schist
♦Shear Schist 1
• Silica Mica Schist
• Pegmatite
•Spod Pegmatite
+Granite
X Diabase
O HCTs
100
1000
Figure 4-6: Waste Rock and Ore Neutralizing Potential Ratio vs. Net Neutralizing Potential
N P vs. AP
1000
Non-PAG ■ Overburden
a
a O Amphibole Gneiss -Schist
Ou 100 O
u O O O Uncn Biotite Gneiss
X Mica Schist
♦ Upper Mica Schist
O n BX 8
_ p Po Mica Schist
v 10 O O �,l>.' O n� ♦ Shear Schist
p■ OT
ao • i Md C : .. v �� • Silica Mica Schist
to • - • N �f m
t • ,• p • Pegmatite
7i 0 ❑ V • Spod Pegmatite
0
w 1 .•❑, + Granite
Z
X Diabase
PAG - NPR = 1
---- NPR =2
0 0 HCTs
0.1 1 10 100
Acid Generating Potential (AP) (kg CaCo3 eq/t)
Figure 4-7: Waste Rock and Ore Acid Generating Potential vs. Neutralizing Potential
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 24

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
NAG vs. NAG pH
60
A
1
■
Overburden
PAG
1
•
Amphibole Gneiss -Schist
1
50
1
♦
Biotite Gneiss
1
0
A
Mica Schist
O
A
A
1
♦
Upper Mica Schist
40
1
2
1
0
Po Mica Schist
s
Non-PAG
0
0
1
♦
Shear Schist
1
30
c
A
1
•
Silica Mica Schist
w
t7
0
1
•
1
•
Pegmatite
d 20
Z
1
1
•
Spod Pegmatite
1 •
+
Granite
Aa, Q
� QQ
1 •�•i
X
Diabase
10
1
��\
1
• •
Q
— —
HCTs
NAG pH=4.5
®�•
— lJ
•
D
0
2 4
6 8 10 12
NAG pH (s.u.)
Figure 4-8: Waste Rock and Ore NAG pH vs. Net Acid Generation
4.2.4 Mineralogy
Samples selected for kinetic testing have also been submitted for mineralogical analysis, including
optical microscopy, XRD and SEM analysis. A split was taken from the composites generated for the
SPLP and LEAF testing for XRD analysis to aid in the interpretation of the leach test results.
The purpose of the mineralogical analysis is to identify site -specific mineralogical characteristics that
influence ARDML. This includes the identification of any sulfide minerals that are present and an
assessment of how their grain size and mineral form will affect future weathering behavior. For
example, whether the sulfides are liberated (i.e., available for reaction) or encapsulated in unreactive
silicate minerals, and therefore unlikely to react. The mineralogical analysis also aims to identify any
minerals that will provide neutralizing capacity and to determine their availability for reaction.
Mineralogy is the key to interpreting results from the static and kinetic tests and may be used in
conjunction with the other test results to assess likely long-term weathering behavior.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 25

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
5 Tailings Characterization
5.1 Tailings Sample Collection
Samples representative of future tailings material have been sourced from various metallurgical test
programs for geochemical characterization testing. This includes six samples from the 2018 pilot plant
and 20 samples from the 2022 North Met program as summarized in Table 5-1.
As described above, the metallurgical process is still under development; however, a preliminary
process flow sheet is provided in Figure 5-1 that shows the points in the process at which the North
Met program samples summarized in were collected. Although subject to change, the current plan is
for ore from the pit to be crushed and ground to -850 pm and sent through a heavy liquid separation
process that produces the DMS tailings. Remaining ore will be ground to -300 pm for further
processing. Several waste streams will be generated during the flotation process that will be combined
and co -disposed in the TSF as shown in Figure 5-1. The DMS tailings are proposed to be co -mingled
with the waste rock and deposited in the waste rock dumps and the fine flotation tailings will be filtered
and dry stacked in the TSF.
As shown in Figure 5-1, a preconcentration step (i.e., ore sorting) will likely be included in the process.
Rejects from the ore sorting process will be comingled with the waste rock and placed on the waste
rock dump. Materials generated from this process are available from the North Met program and have
been included in the characterization program. Albemarle is also currently evaluating the magnetic
separation at various points in the process that may be included in the process flow sheet as shown in
Figure 5-1. However, at this stage, material representative of the rejects from the magnetic separation
are not available. Material from the magnetic separation process will be comingled with the waste rock
and placed on the waste rock dump.
As part of the 2022 North Met program, testing has been done on two master composites both with
and without preconcentration. Variability composites were also included in this test program to capture
the range of ore properties. In addition, process solutions from the metallurgical testwork were
submitted for the analytes in Table 4-4.
Various waste streams from the 2018 pilot plant study were also included in the characterization
program including rejects from the magnetic separation, which are not available from the North Met
program. However, the flow sheet for the 2018 pilot plant was slightly different from the 2022 North Met
program and did not include ore sorting.
In addition to the metallurgical test residues, approximately 10 to 20 additional samples of legacy
tailings will be collected during the ongoing drilling program. Porewater within the tailings will also be
sampled to provide an assessment of constituent leaching under field conditions.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 26

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
Table 5-1: Solid Tailings Samples and Selected Test Methods
Metallurgy
Ore
Location
Sample Name
ABA,
SPLP
LEAF
HCT
Program
Sorting
on Flow
NAG, ICP
(EPA
(EPA
Sheet
1312)
1313 and
(Figure 5-1)
1316)
NorthMet
No Ore
1
Comp 1 DMS Tailings
X
X
Program
Sorting
Comp 2 DMS Tailings
X
X
2
Comp1 Float Tailing
X
X
Comp 2 Float Tailing
X
X
Ore
3
Sorted Comp 1 DMS Tails
X
X
X
X
Sorting
Sorted Comp 2 DMS Tails
X
X
X
X
Sorted Var 1 DMS Tails
X
Sorted Var 2 DMS Tails
X
Sorted Var 3 DMS Tails
X
Sorted Var 4 DMS Tails
X
4
Sorted Var 1 Ore Sorting Float Tails
X
X'
X'
Sorted Var 2 Ore Sorting Float Tails
X
X'
X'
Sorted Var 3 Ore Sorting Float Tails
X
X'
X'
Sorted Var 4 Ore Sorting Float Tails
X
X'
X'
5
Sorted Comp1 Ore Sorting Rejects
X
X
X
X
Sorted Comp 2 Ore Sorting Rejects
X
X
X
X
Sorted Var 1 Ore Sorting Rejects
X
Sorted Var 2 Ore Sorting Rejects
X
Sorted Var 3 Ore Sorting Rejects
X
Sorted Var 4 Ore Sorting Rejects
X
6
Mag concentrate
X
2018 Pilot
No Ore
NA
DMS 1st Pass
X
X
Plant
Sorting
Locked -Cycle Tests
X
X
Floatation Tails
X
X
Magnetic Separation (+6M)
X
Magnetic Separation (-6M/+32M)
X
Blended Fines/Middlings
X
Note: 'Composite of Sorted Variability Ore Sorting Float Tails (1 through 4)
SRK CONSULTING (U.S.), INC. ■ FEBRUARY 15, 2023 27

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
F°rocu�i
Process
Crushing
Mine Rock &
Grinding
No Ore
6M5 HI Coarse DMS
I Concentrate
Grinding
Desliming
Mica Floatation
Spodumene
Flotation
Spodumene
Concentrate
re Sorting
3: DMS Tailings 6'
5, or, Sorting
Concentrafe
Reject
- « DMS Coarser Magnetic
Srparanon
a Coarse DMS
Concentrate
Ore Sorting No Mag Sep
Figure 5-1: Process Flow Sheet for the NorthMet Program
Ore Sorting I-1-0 DMS
Fines
Coarse DMS
Concentrate
SRK CONSULTING (U.S.), INC. ■ FEBRUARY 15, 2023 28

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
5.2 Tailings Test Methods
Test methods selected for the tailings sample are summarized in Table 5-1 and include:
1. Static characterization testing, including ABA, NAG and multi -element analysis
2. Short-term leaching testing, including SPLP, EPA 1313 and 1316 methodologies and
mineralogy
3. Kinetic testing, including HCTs, mineralogy and termination testing
The methods selected for the tailings samples are identical to those being used for characterization of
waste rock and ore samples described in Section 4.2. The only exception is the mineralogical analysis,
which will comprise QEMSCAN and TIMA analysis being completed as part of the metallurgical test
program. In addition, the tailings characterization program will not include the EPA 1314 LEAF method,
as this is an up -flow column percolation method not considered applicable to a dry stack tailings
facility.
6 Data Evaluation and Reporting
SRK will use the results of the static and kinetic geochemical characterization testing to evaluate the
potential for acid generation potential and metal leaching from waste rock, ore and tailings associated
with the Project. The results will be incorporated into numerical models to predict future water quality
associated with the mine facilities and pit lake. Water chemistry modeling allows for the quantitative
assessment of environmental impacts associated with the project and allows for the development of
appropriate engineering design for operation and closure of the mine facilities.
Geochemical test results will be compared to potentially applicable regulatory standards in North
Carolina to provide a context in which to understand and interpret the data.
An interim characterization report will be prepared in 1 sc Quarter 2023 that provides a summary of the
static test results including the short-term leach tests. In addition, this report will include preliminary
kinetic test data; however, the HCT program will be ongoing at the time the report is prepared and
conclusions will be preliminary. Upon completion of the kinetic test program, a comprehensive
characterization report will be prepared that contains full details of the characterization program
methodology and results. In addition, during the HCT program a series of memos will be prepared at
key milestones to provide a summary of the kinetic test results and recommendations for termination of
the cells that have stabilized and have meet the objectives of the test. The results of the numerical
modeling will be provided under separate cover.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 29

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
References
ASTM, 2013a, ASTM D5744 - 13e1. Standard Test Method for Laboratory Weathering of Solid Materials Using a
Humidity Cell.
Bureau of Land Management (BLM), 2008 (updated 2013), Instruction Memorandum No. NV-2013-046, Nevada
Bureau of Land Management Rock Characterization Resources and Water Analysis Guidance for Mining
Activities. Updated September 19, 2013.
Hanahan, J., 1985. The Foote Quarry, Kings Mountain, North Carolina: Revisited, 1984. Rocks & Minerals, 60(2), 76-
82.
International Network for Acid Prevention (INAP), 2014. Global Acid Rock Drainage Guide (GARD Guide).
http://www.gardquide.com/.
Mason, B., 1966, Principles of geochemistry: New York, John Wiley, 329 p.
MEND, 2009. Prediction Manual for Drainage Chemistry from Sulphidic Geologic Materials. MEND Report 1.20.1.
December 2009.
Merschat, A.J., Hatcher, R.D., Jr., Byars, H.E., and Gilliam, W.G., 2012. The Neoacadian orogenic core of the southern
Appalachians: A geo-traverse through the migmatitic Inner Piedmont from the Brushy Mountains to
Lincolnton, North Carolina. In: Eppes, M.C., and Bartholomew, M.J., eds., From the Blue Ridge to the Coastal
Plan: Field Excursions in the Southeastern United States: Geological Society of America Field Guide 29,
2012, p. 171-217.Miller, S., Robertson, A., & Donohue, T. 1997. Advances in acid drainage prediction using
the Net Acid Generation Test, Proceedings on the 4th International Conference on Acid Rock Drainage,
Vancouver, BC, 533-549.
Miller, S., Robertson, A., Donohue, T. 1997. Advances in Acid Drainage Prediction Using the Net Acid Generation Test,
Proceedings on the 4th International Conference on Acid Rock Drainage, Vancouver, BC, p. 533-549.
Sapsford, D.J., Bowell, R.J., Dey, M. and Williams, K.P., 2009, Humidity cell tests for the prediction of acid rock
drainage. Minerals Engineering 22(1), pp25-36.
Schafer, W., 2016. Geochemical Evaluation of Cemented Paste Tailings in a Flooded Underground Mine. Proceedings
IMWA 2016, Freiberg/Germany. Drebenstedt, Carsten, Paul, Michael (eds.). Mining Meets Water — Conflicts
and Solutions.
Sobek, A.A, Schuller, W.A., Freeman, J.R., & Smith, R.M. 1978. Field and laboratory methods applicable to
overburden and mine soils, EPA 600/2-78-054, 203.
SRK, 2021. SEC Technical Report Summary, Initial Assessment, Kings Mountain, North Carolina. Dated December 31,
2021.
US EPA, 1994. Method 1312. Synthetic Precipitation Leaching Procedure. Revision 0. September 1994.
US EPA, 2012a. Method 1313. Liquid -Solid Partitioning as a Function of Extract pH using a Parallel Batch Extraction
Procedure. Revision 0, October 2012
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 30

Kings Mountain Geochemical Characterization Work Plan
Technical Memo
US EPA, 2012b. Method 1316. Liquid -Solid Partitioning as a Function of Liquid -Solid Ratio in Solid Materials using a
Parallel Batch Procedure. Revision 0, October 2012
US EPA, 2017a. Method 1314. Liquid -Solid Partitioning as a Function of Liquid -Solid Ratio for Constituents in Solid
Materials using an Up -Flow Percolation Column Procedure. Revision 1, July 2017.
US EPA, 2017b. Method 1315: Mass Transfer Rates of Constituents in Monolithic or Compacted Granular Materials
Using a Semi -Dynamic Tank Leaching Procedure, July 2017.
US EPA, 2022. Leaching Environmental Assessment Framework (LEAF) Methods and Guidance. Leaching
Environmental Assessment Framework (LEAF) Methods and Guidance I US EPA. Accessed November 7,
2022.
Wilson, W.F and McKenzie, B.J., 1980. Mineral Collecting Sites in North Carolina. 250p. Geologic Survey North
Carolina.
SRK CONSULTING (U.S.), INC. FEBRUARY 15, 2023 31

Attachment 1 Data Evaluation Graphs showing
SPLP/LEAF Composites and HCT Samples