Appendix F LEAF and Humidity Cell

Leaching Environmental Assessment Framework (LEAF)
and Accelerated Weathering of Solid Materials
Using a Modified Humidity Cell (ASTM D 5744-96)
Collaboration Technical Summary
April 2023
Prepared for: Prepared by:
Piedmont Lithium Carolinas, Inc. Marshall Miller &Associates, Inc.
42 East Catawba Street 582 Industrial Park Road
Belmont, NC 28012 Bluefield, Virginia 24605
www.mmal.com

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Leaching Environmental Assessment Framework(LEAF)
and Accelerated Weathering of Solid Materials
1k,
►► Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Summary
April2023
Table of Contents
Page No.
1 Introduction ......................................................................................................................1
2 Leaching Environmental Assessment Framework(LEAF)Testing.........................................2
3 Accelerated Weathering of Solid Materials Using a Modified Humidity Cell
(ASTM D 5744-96)..............................................................................................................4
4 Summary of Results...........................................................................................................5
5 Operation Plan for Monitoring and Potential Mitigation for Waste Rock
Disposal Areas and Backfilled Pits......................................................................................8
5.1 Above-Ground Waste Rock Disposal Area................................................................... 8
5.2 Pit Backfill Waste Rock Disposal Areas......................................................................... 9
Attachments
1 ...................Table of Applicable State and Federal Guidelines for Groundwater and Surface Water
2 ................................................................................................. LEAF Method 1313 Screening Results
3 ....................................................................................Summary of 2019 & 2021-2022 Humidity Cell
(ASTM D5744 [reapproved 2001]) Leaching Results
4 ....................................LEAF Test Results RE: V, Al, As and pH under "natural" leachage conditions
5 ............................ Duration of Elevated pH Relative to Regulatory Standards in Humidity Cell Tests
6 ....................................................................................... Humidity Cell Test Results RE: V, Al, and pH
7 ........................................................Summary of Elevated Parameters in Humidity Cell Test Results
Exhibits
1 ...............................................................................................Conceptual Reclamation Flow Diagram
2 ........................... Conceptual Diagram of Water Collection and Monitoring System in Backfilled Pit
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Leaching Environmental Assessment Framework(LEAF)
and Accelerated Weathering of Solid Materials
►►' ►► Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Summary
April2023
1 Introduction
In response to North Carolina Division of Energy, Mineral, Land, and Resources' (DEMLR) additional
information request item 4, dated January 14, 2022; Piedmont Lithium Carolinas, Inc. (PLCI) is
providing the following details with regard to our current reclamation plan associated with placement
of waste rock and tailings material in above-ground disposal areas and backfilled mine pits. This
document assumes that all tailings and waste rock materials to be exposed of in the proposed above-
ground and pit backfill disposal areas will originate from PLCI's North Carolina mine.
The waste rock and tailings assessment, upon which the reclamation plan is based, has evolved since
the initial submittal of the mine permit application in August 2021. To date, the waste rock and tailings
material assessment includes Acid-Base Account (ABA) testing, "whole rock" elemental determination,
Toxicity Characteristic Leaching Procedure (TCLP), Leaching Environmental Assessment Framework
(LEAF) [LEAF Method 1313], and a kinetic testing program through use of the Accelerated Weathering
of Solid Materials Using a Modified Humidity Cell (ASTM D 5744-96) protocol. The most current
evolution of the assessment includes completion of LEAF testing (as recommended by DEMLR) and
additional kinetic (humidity cell) testing; the results of which are now incorporated into the updated
reclamation plan. Samples for LEAF test analyses were collected and compiled by PLCI and PLCI
coordinated with Eurofins Pittsburgh (Pittsburgh, Pennsylvania) to conduct the LEAF testing. Sample
collection for the humidity cell work was completed by PLCI and Marshall Miller&Associates(MM&A),
and MM&A coordinated with SGS Laboratory(Lakefield, Ontario,Canada)to conduct the ASTM D 5744-
96 testing.
The inclusion of the additional test results into the assessment provides a more thorough understanding
of both the short-term and long-term potential leaching characteristics associated with the waste rock
and concentrator plant tailings (both with and without by-products associated with feldspar recovery).
In this context, the LEAF testing provides an initial screening "snapshot" of potential "worst case"
leaching conditions under various hypothetical scenarios and helps to identify Constituents of Potential
Concern (COPC). Subsequently, the humidity cell testing (ASTM D 5744-96) provides results that are
indicative of more representative (but still potentially aggressive compared to actual field conditions),
long-term expected conditions of leaching potential.The humidity cell testing provides a means to more
thoroughly evaluate the COPCs identified by the LEAF testing.
The LEAF and humidity cell analyses indicate that production of acidic drainage from the waste rock
and tailings, initially considered to be a possibility in some cases, is not expected. As discussed in
previously submitted information, the waste rock for the site was characterized as either Potentially
Acid Generating (PAG) rock or non-Potentially Acid Generating (non-PAG).The distinction between the
PAG and non-PAG rock was based on previous ABA testing that indicated that some of the waste rock
from the East Pit Extension area (the southeast corner of the East Pit) had the potential to create acidic
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Leaching Environmental Assessment Framework(LEAF)
and Accelerated Weathering of Solid Materials
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conditions. The distinction was originally identified as a change in rock type by PLCI geologists during
exploration drilling activities. In general, approximately 93 percent of the waste rock for the entire mine
is amphibolite that is non-PAG throughout. The remaining 6-7 percent of the waste rock is a mixture of
schist, mudstone, and amphibolite that was initially suspected of containing some PAG material. While
initial ABA testing suggested the PAG material had the potential to produce acidic conditions, acidic
conditions were not observed in the long-term results from ASTM D 5744-96 (humidity cell) testing. In
contrast, the newly-available test data indicate that the waste material (waste rock and concentrator
tailings) has the potential to temporarily elevate pH values in the earliest stage of leachate production,
with long-term humidity cell testing showing that the elevated pH values are expected to quickly and
naturally buffer to a near-neutral pH value. The behaviors of COPCs identified by LEAF and further
analyzed via ASTM D 5744-96 (humidity cell testing) are discussed in subsequent sections below. In
general, the results of the revised assessment suggest that initial placement of waste material may be
expected to result in a "first flush" of water drainage that temporarily exhibits elevated pH values, but
that will naturally buffer to a near neutral pH condition. The results of the testing indicate that the
temporarily elevated pH leachate can be associated with concentrations of COPCs that, in some cases,
may have the potential to temporarily exceed regulatory guidelines for groundwater and/or stream
water quality. Long-term ASTM D5744-96 results indicate that, in nearly all cases, elevated pH values
and associated COPC concentrations are expected to decrease rapidly as leaching progresses.
In consideration of the results of the updated assessment, PLCI has modified the previous reclamation
plan. The revised reclamation plan now includes placement of only waste rock and concentrator plant
tailings for backfilling of pits and construction of the proposed above-ground waste rock disposal areas.
Placement of tailings associated with the conversion plant into above-ground waste rock disposal areas
and backfilled pits on the mine site is not part of the current revised plan. The subsequent sections of
this document include summary background information for LEAF and ASTM D 5744-96 (humidity cell)
testing methodologies; a summary of the results from the LEAF and ASTM D 5744-96 testing;and details
of the revised waste disposal and reclamation plan. A table summarizing applicable parameter
guidelines for groundwater and surface water is included as Attachment 1.
2 Leaching Environmental Assessment Framework
(LEAF) Testing
PLCI (via Eurofins) conducted multiple LEAF Method 1313, pH Dependence tests to evaluate "worst
case" leaching potential for numerous potential waste material combinations. The material analyzed
with LEAF Method 1313 included both waste rock (PAG and non-PAG) and tailings from the proposed
concentrator plant. The LEAF testing (recommended by DEMLR) supplemented and confirmed results
of other testing (ASTM D 5744-96) conducted by PLCI. The LEAF test results assist with developing
management and mitigation measures to minimize and prevent leaching of COPCs.
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Leaching Environmental Assessment Framework(LEAF)
and Accelerated Weathering of Solid Materials
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The LEAF testing was completed on representative 1 kilogram (kg) samples, with potential material
combinations based on anticipated production rates during normal mining operations. The current
assessment considers LEAF testing of the following material combinations:
> PAG waste rock
> non-PAG waste rock
> Concentrator Tailings
> PAG/non-PAG waste rock
> PAG/non-PAG/Concentrator Tailings
> PAG/Concentrator Tailings
> non-PAG/Concentrator Tailings
Based on input from Eurofins, the LEAF Method 1313 testing was conducted over a pH range from 4.0
— 9.0, and tests under Synthetic Precipitation Leaching Procedure (SPLP) (beginning pH near that of
rainwater) and "natural" (de-ionized water) conditions were also completed as part of the LEAF testing
program. The LEAF sample material was milled to a size of 2 millimeters or less, which is much smaller
than the expected size of waste rock material to be placed under actual conditions. The reduced size,
and therefore increased surface area, of the material tested with LEAF methods artificially increases
the potential leachability of the material, as compared to expected actual conditions.
The LEAF Method 1313 testing provides an initial screening at a wide range of pH values including those
that are unrealistic for the project conditions; consequently, LEAF 1313 provides only an initial
"snapshot" for COPCs that could be associated with leaching of the waste material. The results from
LEAF are generally consistent with the earliest stages of long-term ASTM 5744-96 (humidity cell) test
results (further discussion below). The LEAF How-To Guide (May 2019) issued by the United States
Environmental Protection Agency (EPA) establishes that the various LEAF methods are not regulatory
compliance tests, and should not be used as such. Instead, LEAF is intended to help provide information
about various leaching scenarios so that adverse conditions can be avoided via implementation of
mitigation strategies. Specifically, the LEAF How-to Guide states:
"The LEAF tests and approach is voluntary and not a requirement under the Resource
Conservation and Recovery Act (RCRA). This guidance provides a general approach that needs
to be tailored to the specific application or regulation under which it is being used.....LEAF is not
a regulatory test but may be useful in support of evaluations not designed to meet requirements
under the RCRA regulations. The use of LEAF on a site-specific basis needs to be tailored to the
questions being asked. The usefulness of LEAF testing will depend on how well test results
estimate environmental conditions for a specific application."
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Leaching Environmental Assessment Framework(LEAF)
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For the current assessment, LEAF Method 1313 testing has been completed on seven samples
representative of the site (not including conversion plant tailings). Summary results tables for each of
the individual LEAF tests are included in Attachment 2. The tables summarize results of the testing for
laboratory-controlled pH ranges from 4.0 to 9.0, for "Natural" conditions, and for SPLP analysis. The
results of the LEAF 1313 testing are discussed in detail in the Summary of Results section of this
document.
3 Accelerated Weathering of Solid Materials Using a
Modified Humidity Cell (ASTM D 5744-96)
Humidity Cell Testing is a kinetic test that subjects a material to varying oxidizing and rewetting
conditions over time to simulate the changes in drainage quality with changing composition of a
material undergoing leaching. The test method involves periodic (often weekly) leaching of a 1-kg
sample of solid material with a water of specified purity. In the current case,the testing was completed
with de-ionized water. The test is commonly used in the mining industry to evaluate how drainage
characteristics from mining waste material may be expected to change over time. Important notes
excerpted from the ASTM International [formerly American Society for Testing and Materials (ASTM)]
information for humidity cell testing(ASTM D 5744-96)1 are included below to emphasize the relevancy
of the test method to the current assessment:
"This accelerated weathering test method is designed to increase the geological-chemical-
weathering rate for selected 1000-g solid material samples and produce a weekly effluent that
can be characterized for solubilized weathering products."
"The purpose of this accelerated weathering procedure is to determine the following: (1) whether
a solid material will produce an acidic, alkaline, or neutral effluent, (2) whether that effluent will
contain diagnostic cations (including trace metals) and anions that represent solubilized
weathering products formed during a specific period of time, and (3) the rate at which these
diagnostic cations and anions will be released (from the solids in the effluent) under the closely
controlled conditions of the test."
"The principle of the accelerated weathering test method is to promote more rapid oxidation of
solid material constituents than can be accomplished in nature and maximize the loadings of
weathering reaction products contained in the resulting weekly effluent."
1 D 5744—96(Reapproved 2001),Standard Test Method for Accelerated Weathering of Solid Materials Using a Modified Humidity Cell,ASTM International.
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and Accelerated Weathering of Solid Materials
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"This test method has been tested on both coal and metal mine wastes to classify their respective
tendencies to produce acidic, alkaline, and neutral effluent, and to subsequently measure the
concentrations of selected inorganic components leached from the waste."
"An assumption used in this test method is that the pH of each of the leachates reflects the
progressive interaction of the interstitial water with the buffering capacity of the solid material
under specified laboratory conditions."
As stated, the humidity cell testing allows for assessment of the effects on the leachate from
progressive buffering capacity of the solid material overtime, a factor that is not accounted for by LEAF
1313 testing. The humidity cell testing included introduction of de-ionized water and the waste rock
material was reduced to a size much smaller (less than 6.35 mm) than that of the planned waste rock
material, both of which factors increase the propensity for leaching to occur. For the current
assessment, ASTM D 5744-96 testing has been completed for thirteen (13) samples. Attachment 3
includes individual results summary sheets for the humidity cell tests.
4 Summary of Results
As stated above, the results of the recent testing program and revised assessment resulted in
modification of the proposed reclamation plan. Specifically, the current plan for on-site material
disposal includes only waste rock and concentrator plant tailings (with by-products recovery), and
excludes conversion plant tailings. The conversion plant tailings will be transported off-site to an
appropriate disposal facility (facility selection process is in-progress). The following discussion relates
to results specific to the actual planned waste materials.
Results from LEAF and ASTM D 5744-96 (humidity cell) test methods provide information for
identification of COPCs and for assessment of both short-term and long-term leaching potential from
the proposed waste material. The LEAF testing, and long-term results from humidity cell leaching over
extended periods, identify that pH values from initial leaching associated with the planned waste
material (PAG waste rock, non-PAG waste rock, and concentrator plant tailings) are expected to be
elevated above neutral.The pH values are sometimes in excess of applicable groundwater and surface
water regulatory and/or guidance standards in the short-term LEAF tests (see Attachment 4 for LEAF
test results summary table) and rarely and only marginally so in the very early phases of leaching in a
few of the humidity cell samples (see Attachment 5). Comparison of the Attachment 4 and Attachment
5 tables indicates that the pH values for the LEAF test results are generally comparable to the pH values
observed in the very early stages of the humidity cell testing (both are elevated above neutral, but the
LEAF results more often exceed standards in a laboratory-induced condition), but humidity cell results
(Attachment 5) indicate that the elevated pH values are quickly attenuated by the natural buffering
capacity of the material and decrease to within regulatory standards within the first week of humidity
cell testing. The long-term humidity cell test results, which involve the repeated introduction of
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Leaching Environmental Assessment Framework(LEAF)
and Accelerated Weathering of Solid Materials
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oxygenated water, are expected to be most representative of actual site conditions at the PLCI mine
site.
The short-term elevated pH values of the leachate are associated with increased concentrations of
Vanadium (V) and Aluminum (Al), as the solubility of those constituents is increased at those higher pH
levels. In some LEAF test samples (where pH is greater than —9.3), those parameters in the leachate are
elevated above regulatory standards for ground or surface waters (Attachment 4). In the humidity cells,
the immediate ("first flush" or Week 0 leach event) on rare occasions exhibited a pH marginally higher
than standards; however, twenty (20) to thirty (30) weeks of repeated leaching resulted in no
exceedances of standards in V or Al concentrations (Attachment 6). Attachment 7 summarizes all
instances where humidity cell test leachate exceeds the groundwater or surface water guidance values.
The humidity cell results indicate that initially-elevated pH values (which generally are associated with
higher concentrations of V and Al) drop to within standards by the next flushing event (Week 1).
Both LEAF Method 1313 results and ASTM D 5744-96 (humidity cell) results consistently indicate that
pH values from the waste material are likely to be initially elevated in the very early stages of waste
placement. The results from both tests suggest that the temporarily-elevated pH values have the
potential to result in elevated concentrations of V and Al, which are recognized as COPCs. However,
only a small percentage of the LEAF test results (and none of the early humidity cell results) indicate
concentrations for those parameters that exceed regulatory standards. In addition, the humidity cell
results indicate that, under continuous waste disposal operations over time, the ever-increasing mass
of disposal material allows for attenuation via the natural buffering capacity of the waste material that
results in compliant pH and a diminishing rate of release of high-pH-soluble parameters (V and Al). The
overall indication is that pH, V and Al are unlikely to exceed applicable regulatory and/or guidance
standards in water passing through waste rock disposal facilities associated with the subject mine. The
results also indicate that V and Al concentrations are a direct result of elevated pH, and therefore can
be mitigated (if necessary) via commonly-implemented pH-control measures (see further discussion in
subsequent section).
Arsenic (As) occasionally shows up in leaching test results at concentrations greater than 10 µg/L (the
drinking water and North Carolina groundwater standard), but at levels that are within the range of,
and below, some of the levels shown to exist naturally in groundwater chemistry samples from
monitoring wells in the project area. Unlike V and Al, As does not appear to correlate well with the pH
of the leachate.Two of seven LEAF samples showed As at levels greater than 10 µg/L, and both of those
included PAG waste rock (which is known to be limited to the East Pit Extension area and does not
exhibit acidic conditions due to its inherent alkalinity, as shown by subsequent kinetic testing). In the
humidity cell program, one of two mudstone samples (again, rock that was originally designated PAG,
but does not yield acidic conditions) showed As to leach over the duration of the 20-week program.
Drilling information indicates that mudstone is only expected to be present in the East Pit Extension
area and is only expected to constitute a small percentage of the overall waste rock material. In
contrast, amphibolite (estimated to represent the majority of waste rock in the entire mine) and schist
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Leaching Environmental Assessment Framework(LEAF)
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(only present in the East Pit Extension) rock samples showed no leaching of As at concentrations
exceeding standards. Importantly, groundwater samples collected by PLCI in April 2022 from the
recently-installed site monitoring/pump test wells show As to commonly be present in the site
groundwater, an observation that is generally consistent with publicly-available water quality data for
the area. In the April 2022 groundwater samples, the As content exceeded the primary drinking water
standard in approximately one-fourth of the wells,and in one well it occurred at a concentration similar
to the highest concentrations seen in the leaching test results. Therefore, at the levels indicated by the
test program results, Arsenic is considered to be within background levels common in this area of
Gaston County and is not considered a COPC specific to the proposed project.
The LEAF Method 1313 test results indicate the potential for Cobalt (Co)to be leachable, but only under
certain geologic conditions and only where pH is lower than the expected range of approximately 7.5
to 8.5. LEAF results under natural conditions do not indicate exceedances of North Carolina surface and
ground water guidelines for Co. Only one out of the 13 humidity cell tests indicated Co to be leachable
at a concentration that exceeded the groundwater guideline.That one humidity cell test involved schist,
a rock type that is only present in the East Pit Extension area.
In summary, the LEAF Method 1313 and ASTM 5744-96 (humidity cell) test results indicate that the
waste rock and concentrator tailings have the potential to create temporarily-elevated pH levels, and
associated temporarily-elevated concentrations of some COPCs, in the earliest stages of material
placement. However, the long-term humidity cell testing indicates that the temporarily-elevated pH
values and associated slightly elevated COPC concentrations are quickly attenuated by the natural
buffering capacity of the bedrock material. In addition, since the COPCs that are associated with
elevated pH values are pH-dependent, pH-control mitigation measures are applicable. The results
indicate that the potential for adverse effects to the environment are not expected and can be reduced
or eliminated when pH is maintained between approximately 7.5 to 8.5 through a combination of the
material's natural buffering capacity and pH control mitigation measures. In addition to the effects of
temporarily-elevated pH (Al and V) in the early stages of waste disposal, certain test results indicate
that As and Co are infrequently present under specific geologic and geochemical conditions. Of those,
As concentrations from testing are associated only with mudstone and are within the range of As
concentrations observed in local groundwater. Elevated Co concentrations can be expected to occur
only at lower pH values outside the expected pH range for discharge from the waste material and only
appear to be associated with schist, a rock type that is only present in the East Pit Extension area.
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Leaching Environmental Assessment Framework(LEAF)
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5 Operation Plan for Monitoring and Potential
Mitigation for Waste Rock Disposal Areas and
Backfilled Pits
The current mine reclamation plan includes placement of waste rock and concentrator plant tailings in
both above-ground disposal areas as well as in open pit mine areas where mining has been completed.
Monitoring and mitigation (if necessary) strategies for each scenario are discussed below. In general,
the results of the geochemical analyses completed for the waste rock and concentrator plant tailings
(including, but not limited to, humidity cells and LEAF testing) indicate that long-term adverse
environmental conditions are not expected to occur associated with either the above-ground waste
disposal sites or the backfilled pits. As discussed in previous sections, the analysis indicates that there
is a potential for water with elevated pH values (with associated increased concentrations of Al and V)
to temporarily discharge from the waste material in early stages of placement, but long-term leach tests
indicate that the natural buffering capacity of the material will attenuate both the pH and associated
COPC concentrations to within regulatory guidance values. A conceptual flow diagram is included as
Exhibit 1 to illustrate the concepts discussed below.
5.1 Above-Ground Waste Rock Disposal Area
Design of the above-ground waste rock disposal areas inherently facilitates containment and
monitoring of runoff from the waste material via site construction and stormwater runoff control
measures. Prior to placement of material in the waste rock area, the native, low-permeability silt and
clay-rich soil will be pre-compacted to reduce the potential for infiltration of runoff from the waste
material into the underlying ground. Incremental placement of waste material onto the pre-compacted,
low-permeability silt and clay-rich soil will provide additional densification and compaction of the soil
as the waste disposal area is constructed. Rainwater that infiltrates through the waste material will
percolate down to the base of the pile, be impeded by the low-permeability soil beneath the waste pile,
and discharge to sediment control ponds that are part of the disposal area design. As the pile is
constructed from the bottom upwards, each incremental level of the out-slope will be covered with soil
and vegetated to progressively decrease the amount of infiltration. Upon completion of the final waste
rock and tailings storage area, the top will be "domed" to create positive drainage, to decrease
infiltration, and to reduce the potential for pooling of rainwater on the pile. Each sediment control pond
is designed to collect runoff from a specific area of the waste rock pile, facilitating thorough monitoring
of discharge.
Water quantity and quality monitoring for above-ground waste disposal areas will be conducted for the
inflow and outflow of sediment control ponds that are part of the existing waste rock pile design
(monitoring will be done immediately upstream and downstream of the pond). In addition, monitoring
wells positioned along the perimeter of the proposed mine area will be used to monitor for any adverse
groundwater effects from the waste rock pile or other portions of the operation. Monitoring of water
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quality of the inflow to each sediment pond will allow PLCI to evaluate the need for temporary water
treatment mitigation procedures on a regular basis. Monitoring of the outflow of each pond will allow
PLCI to observe the quality of the final discharge, assess the performance of mitigation procedures, and
adjust treatment as necessary. The sampling and testing will be conducted using industry-standard
procedures and methods, and certified laboratories. Water quantity and quality monitoring for above-
ground waste rock disposal areas will be completed monthly for the first six months of construction and
quarterly thereafter, with the option to adjust the frequency of the monitoring based on observed
conditions, and subject to review and approval by NC DEMLR. If water quality mitigation is required at
a pond,the primary method will be pH adjustment using a low-pH additive, supplemented byflocculant
addition if necessary. Adjustment of the pH of water is a common and effective mitigation strategy for
a wide variety of mineral, hard rock, and surface mining projects. Upon completion of reclamation
activities for above-ground waste disposal areas, water quantity and quality monitoring will be
continued until hydrologic equilibrium is established and water quality parameters are stabilized and
within regulatory or background ranges.
5.2 Pit Backfill Waste Rock Disposal Areas
Placement of waste material into open-pit mining areas will start after mine pits are excavated to their
planned completion depth by following the proposed reclamation plan reviewed and approved by
DEMLR. During mining and backfilling of a pit, groundwater (and direct rainfall) will enter the pit, be
collected, and be pumped out of the pit to a specifically designed pit discharge pond. As indicated on
Exhibit 1,water from the pit discharge ponds may either be used at the concentrator plant or discharged
to streams.The pit discharge ponds provide locations for monitoring water quality from the pit (and for
conducting pH modifications as necessary) in the same way that water will be monitored in the
sediment control ponds associated with the above-ground waste disposal area (previously discussed).
Due to the reverse-gradient associated with the excavation of and pumping from the open pit,
groundwater will flow into, and not out of,the pit up until the time that the water level in the backfilled
pit is allowed to reach a level equal to, or greater than, the surrounding natural groundwater table.
As a pit is progressively backfilled, groundwater and rainfall will infiltrate and accumulate in the waste
material.As pit backfilling progresses, PLCI will monitor the water level and water quality characteristics
of water accumulating in the backfill via a water collection and monitoring system (see Exhibit 2). The
system will provide PLCI with the means to monitor and sample water in the backfill. The water
collection and monitoring system also provides a means for dewatering the backfill, if necessary, in the
event of adverse environmental impact. Pumping for mitigation purposes would establish a reverse-
gradient condition and prohibit adverse water from moving away from the pit into the groundwater
system. In the event that backfill dewatering is necessary for mitigation purposes (due to undesirably
low or elevated pH and associated COPCs), water pumped from the backfill would be monitored and
treated (pH control) at the pit discharge pond on a monthly basis (with the option to adjust the
frequency of monitoring based on observed conditions) until the pH condition is attenuated by the
natural buffering capacity of the material.
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Upon completion of backfilling of a pit with waste rock and concentrator tailings to the elevation of the
surrounding ground,the material will continue to be piled in a manner consistent with the construction
specifications defined in the permit (in a similar manner to the construction of the above-ground waste
rock disposal areas). As such, incremental levels of the pile on top of the backfilled pit will be covered
with low-permeability soil and vegetated progressively to reduce infiltration and reduce excess
stormwater runoff. Upon completion of the final above-ground pile on top of a backfilled pit, the top
of the constructed pile will be domed to create positive drainage and reduce infiltration. Water
monitoring from each backfilled pit will be continued after reclamation until hydrologic equilibrium is
established and water quality parameters are stabilized and within regulatory or background ranges.
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Attachments

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Piedmont Lithium
Attachment 1: Table of Applicable State and Federal Guidelines
for Groundwater and Surface Water
USEPA North Carolina North Carolina
Drinking Water Ground Water Surface Water Standard
Parameter Standard Standard Acute Chronic
(Units:µg/L)
Hg 2 1 0.012 0.012
Ag 100* 20 Calculate
As 10 10 340 150
B 300 H.A. 700 34,000 TV 7,300 TV
Ba 2,000 700 21,000 TV
Be 4 4 65 6.50
Bi
Cd 5 2 Calculate
Co 1 16 TV 1.6 TV
Cr+6=16 Cr+6=11
Cr 100 10 Calculate
Cu 1,300 A.L. 1,000 Calculate
Mo 51,000 TV
Ni 100 H.A. 100 Calculate
Pb 15 A.L. 15 Calculate
Sb 6 1 5,300 TV
Se 50 20 5 5
Sn 2,000
Sr 25,000 H.A. 2,000
Ti
Th
TI 2 2
u 30
V 7
W
y
Zr
(Units:mg/L)
Al 0.05-0.2* 0.75 0.30
Fe 0.3* 0.3
K
Li
Mg
Mn 0.05* 0.05
Na
P
Si
Zn 5* 1.00 Calculate
SO4 250* 250
F 2* 2 68 2
Chloride 250* 250 230 230
Ca
NO3 10 10
Acidity
Alkalinity
Hardness 100
(Units:pH in Standard Units,EC in µS/cm)
pH 6.5-8.5 6.5-8.5 6-9 6-9
EC
Drinking Water/
* Secondary Standard
Groundwater H.A. Health Advisory
A.L. Action Level
Surface Calculate: Water quality standard for
Water parameter depends upon water hardness.
TV: In-stream target value

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
PAG Composite
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAF.1
(Note:The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF methods are not
regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various leaching scenarios so that adverse
conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH9 @pH8 @aH7 I @pH5.5 @pH4 SPLP Natural
(Units:µg/L)
As 6.3 3.6 1.3B 7.6 17 12 8.9
1.5 8 DUP 8.2 8 DUP 32 8 DUP 15 DUP
Ba <3.1 10 15 26 210 <3.1 <3.1
390 DUP
Be <0.27 <0.27 <0.27 <0.27 1.3 <0.27 <0.27
4l8 DUP
Cd <0.22 0.28 J <0.22 0.39 J <0.22 <0.22 <0.22
<0.22 DUP <0.22 DUP
Co <0.26 0.51 2.9 B 35 35 <0.26 <0.26
8.4 8 DUP 68 8 DUP
Cr,Total <1.5 <1.5 <1.5 <1.5 9.4 1.5 J <1.5
74 DUP <1.5 DUP
Ni <0.52 0.23 22 100 150 0.66 J 0.59 J
0.741 DUP 9.6 DUP 52 DUP 200 DUP <0.52 DUP
Pb <0.17 0.21 J <0.17 <0.17 1.1 0.59 J 2.5
<0.17 DUP 12 8 DUP 1.1 DUP
Se <0.74 0.77 J <0.74 <0.74 <0.74 <0.74 <0.74
TI <0.47 0.64 J <0.47 <0.47 <0.47 <0.47 <0.47
0.551 DUP
V 13 3.1 4.2 6.2 47 20 20
4.0 DUP 140 DUP 17 DUP
(Units:mg/L)
Acidity -17.9 -63.4 -68.5 10.7 150 -28 <5
-23.4 DUP -22.8 DUP 320 DUP 180 DUP -18 DUP
Alkalinity 38 120 98 44 <5 37 38
61 DUP 50 DUP <5 DUP
Al 0.57 0.073 0.045 0.360 5.400 1.400 1.500
0.0271 DUP 44.0 DUP
Ca 20 93 120 280 240 5.5 4.5
68 DUP 180 DUP
Fe 0.037 J <0.028 0.044 J 13.00 70.0 0.38 0.34
0.055 DUP 0.20 DUP 89.0 DUP 0.20 DUP 0.29 DUP
K 12 12 16 16 24 8.6 8.7
16 DUP 7.9 DUP
Li 0.19* 0.22* 0.26 B 0.34* 0.59 0.16 0.17
0.82 8 DUP
Mg 2.3 5.5 6.8 9.6 17.0 0.55 0.39 J
24 DUP
Mn 0.0017 J B 0.18 B 0.61 1.60 B 1.80 0.0054 0.0045 J
0.28 DUP
Na 4 3.9 5.5 4.9 7.4 3.7 3.2
I1.0 DUP
P <0.057 <0.057 <0.057 0.22 J 0.97 <0.057 <0.057
0.061 l DUP 15.0 DUP 1.1 DUP
Si 2.5 3.9 6.9 16.0 31.0 3.5 3.3
45.0 DUP
Zn <0.0029 0.0034 J <0.0029 0.037 0.10 0.0046 J 0.0032 J
0.0069 DUP 0.0063 DUP 0.21 DUP
(Units:pH in Standard Units,EC in µS/cm)
pH 9.4 7.9 7.3 5.5 4.3 9.8 9.8
SC 220 640 710 1800 1800 81 80
480 DUP 630 DUP 1900 DUP
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
non-PAG/PAG/Concentrator Tailings with By-Products
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAF.2
(Note: The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF methods are not
regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various leaching scenarios so that adverse
conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH9 @pH8 @pH7 I @pH5.5 @pH4 SPLP Natural
(Units:µg/L)
As 1.3 1.0 5.8 7.3 6.8
5.9 DUP 4.2 DUP 2.7 DUP
Ba 13 48 170 4.6 JB 4.3 J,B
91 DUP
Be <0.27 <0.27 0.84 J <0.27 <0.27
<0.27 DUP
Cd <0.22 <0.22 0.42 J <0.22 <0.22
0.25J DUP
Co <0.26 0.40 J 33 <0.26 <0.26
32 DUP
Cr,Total <1.5 <1.5 3.9 <1.5 <1.5
<1.5 DUP
Ni <0.52 0.82 J 40 <0.52 <0.52
33 DUP
Pb <0.17 <0.17 <0.17 <0.17 <0.17
<0.17 DUP
Se <0.74 <0.74 <0.74 <0.74 <0.74
<0.74 DUP
TI <0.47 <0.47 0.63 J <0.47 <0.47
0.5 J DUP 0.571 DUP
V 5.8 3.1 12 23 36
3.8 DUP 23 DUP
(Units:mg/L)
Acidity -16.6 -33.5 6.1 60 -15.1 -13.1
43 DUP
Alkalinity 41 63 40 9.4 <5 36 37
52 DUP <5 DUP
Al 0.2 0.024 J 2.6 1.1 1.6
1.1 DUP 1.4 DUP
Ca 32 78 130 6.4 3.3
110 DUP 5.4 DUP
Fe <0.028 <0.028 28.0 0.22 0.34
21.0 DUP 0.48 DUP
K 7.8 11.0 14.0 9.1 8.8
14.0 DUP 9.8 DUP 9.3 DUP
Li 2.0 B 1.7 B 0.49 0.22 0.28
0.44 DUP 0.20 DUP
Mg 2.4 4.7 8.1 0.78 0.34 J
7.7 DUP 0.71 DUP
Mn 0.0054 B 0.32 B 2.1 0.0029 J 0.0042 J
1.8 DUP
Na 9.3 11.0 5.1 4.2 5.2
4.8 DUP 5.0 DUP
P <0.057 <0.057 4.8 0.0811 0.111
2.6 DUP 0.1 J DUP
Si 3.1 7.3 22.0 3.0 3.7
18.0 DUP
Zn <0.0029 <0.0029 0.11 <0.0029 <0.0029
0.078 DUP
(Units:pH in Standard Units,EC in µS/cm)
pH 8.9 7.5 6.6 5.8 4.5 9.2 9.6
5.1 DUP 9.3 DUP
SC 200 450 530 1000 1100 93 80
330 DUP 89 DUP
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
PAG/Concentrator Tailings with By-Products
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAF.3
(Note: The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF methods are not
regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various leaching scenarios so that adverse
conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH9 @pH8 @pH7 I @pH5.5 @pH4 SPLP Natural
(Units:µg/L)
As 8.9 13 3.4 5.6 34 22 32
5.7 DUP 3.9 DUP 7.1 DUP 14 DUP 29 DUP
Ba <3.1 7.2 J 18 46 170 <3.1 6.2 J
Be <0.27 <0.27 <0.27 <0.27 3.1 <0.27 <0.27
Cd <0.22 <0.22 <0.22 0.35 J 0.53 J <0.22 <0.22
Co <0.26 <0.26 0.66 43 64 <0.26 0.45 J
1.6 DUP
Cr,Total <1.5 <1.5 <1.5 <1.5 74 <1.5 2.1
Ni 0.83 J 0.95 J 4.9 13.0 210 0.86 J 1.6
16 DUP 1.1 DUP
Pb <0.17 <0.17 <0.17 <0.17 1.1 <0.17 0.27 J
Se <0.74 <0.74 <0.74 <0.74 <0.74 <0.74 <0.74
TI <0.47 <0.47 <0.47 <0.47 <0.47 <0.47 <0.47
V 8.9 2.8 1.8 5.0 49 17 27
7.0 DUP 3.0 DUP 20 DUP
(Units:mg/L)
Acidity -17.6 -31.9 -15.2 8.1 160 -6.71 <5
<5 DUP -36.4 DUP -21.6 DUP <5 DUP -12.9 DUP
Alkalinity 38 73 94 35 <5 33 37
64 DUP 74 DUP 9.1 DUP
Al 0.84 0.14 0.028 J 0.51 6.50 1.3 2.3
0.77 DUP 0.18 DUP <0.016 DUP 1.7 DUP
Ca 8.2 48 120 250 190 6.0 4.2
10.0 DUP 84 DUP
Fe 0.11 <0.028 <0.028 19.0 58.0 0.19 0.74
<0.028 DUP 0.36 DUP 0.49 DUP
K 8.9 13.0 11.0 18.0 17.0 11.0 12.0
9.3 DUP I1.0 DUP 14.0 DUP
Li 0.15 0.18 B 3.10 B 0.45 B 0.49 0.18 0.20
0.21 DUP
Mg 0.9 3.7 3.7 9.3 11.0 0.55 0.56
1.1 DUP 2.8 DUP 4.8 DUP 0.63 DUP
Mn 0.0017 J 0.067 B 0.29 B 2.5 B 2.4 0.0022 J 0.0086
0.82 DUP 0.0057 DUP
Na 3.2 3.9 11.0 5.0 4.7 5.2 6.3
2.9 DUP 2.8 DUP 3.8 DUP 5.4 DUP
P <0.057 <0.057 <0.057 <0.057 4.9 <0.057 <0.057
Si 2.2 3.2 7.1 17.0 23.0 3.1 4.7
2.6 DUP 5.7 DUP 3.9 DUP
Zn <0.0029 <0.0029 0.0043 J 0.056 0.12 <0.0029 0.0031
(Units:pH in Standard Units,EC in µS/cm)
pH 9.3 8.0 7.4 5.6 3.8 9.4 9.6
6.9 DUP
SC 180 480 610 18 1700 96 92
370 DUP 1700 DUP
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
Sample 1-Concentrator Tailings with By-Products
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAF.4
(Note: The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF methods are not
regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various leaching scenarios so that adverse
conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH9 @pH8 @pH7 I @pH5.5 @pH4 SPLP Natural
(Units:µg/L)
As 0.801 0.65 J 0.811 5.2 2.1 2.3
1.3 DUP 1.9 DUP
Ba <3.1 8.3 J 18 99 <3.1 4.6 JB
78 DUP <3.1 DUP
Be <0.27 0.35 J 3 17 <0.27 <0.27
Cd <0.22 0.49 J 1.7 3.3 <0.22 <0.22
2.0 DUP
Co <0.26 5.5 26 59 <0.26 <0.26
6.9 DUP
Cr,Total <1.5 <1.5 <1.5 410 <1.5 <1.5
4.5 DUP 310 DUP
Ni <0.52 29 130 390 <0.52 <0.52
33 DUP 340 DUP
Pb <0.17 <0.17 <0.17 0.37 J <0.17 <0.17
Se <0.74 <0.74 <0.74 <0.74 <0.74 <0.74
0.791 DUP
TI <0.47 0.75 J 0.95 J 1.7 <0.47 <0.47
1.1 DUP 1.4 DUP
V 0.94 J <0.78 <0.78 13 2.9 2.7
1.0 DUP 0.851 DUP 9.4 DUP 2.4 DUP 3.6 DUP
(Units:mg/L)
Acidity -38.4 -31.1 140 200 -18.3 -13.1
-10.7 DUP 240 DUP -11.0 DUP
Alkalinity 52 54 8.6 <5 36 36
30 DUP <5 DUP
Al 0.14 0.028 J 0.88 4.70 B 0.59 0.65
0.099 DUP 1.3 8 DUP 4.10 DUP 0.50 DUP 0.71 DUP
Ca 28 88 110 130 7.5 6.5
74 DUP 5.6 DUP
Fe 0.035 J 0.063 50.0 120.0 0.057 0.087
0.094 DUP 1.70 DUP 62.0 DUP 0.061 DUP
K 4.9 6.9 7.3 9.2 5.0 4.5
5.8 DUP 8.5 DUP 7.6 DUP
Li 0.26 B 0.93 B 1.50 B 2.30 0.27 0.25
0.69 DUP 1.50 DUP 1.70 DUP
Mg 1.3 3.2 4.0 4.9 0.5 0.43 J
2.9 DUP
Mn 0.17 B 9.0 B 16.0 B 23.0 0.011 0.0091
8.2 DUP 17.0 DUP 0.0071 DUP
Na 3.3 4.7 4.5 5.4 4.4 3.8
3.9 DUP 5.2 DUP 4.6 DUP 4.2 DUP
P 0.081 J <0.057 <0.057 2.0 J 0.27 J 0.241
4.0 DUP
Si 3.4 9.5 14.0 21.0 3.4 3.3
8.0 DUP
Zn <0.0029 0.017 0.28 0.61 B <0.0029 <0.0029
0.043 DUP 0.59 DUP
(Units:pH in Standard Units,EC in µS/cm)
pH 8.1 6.5 5.5 4.0 9 8.9
7.3 DUP 8.8 DUP
SC 290 760 1200 1700 87 74
560 DUP 1500 DUP
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
non-PAG/Concentrator Tailings with By-Products
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAFS
(Note:The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF methods are not
regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various leaching scenarios so that adverse
conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH9 @pH8 @aH7 I @pH5.5 @pH4 SPLP Natural
(Units:µg/L)
As 0.66 J 0.39 J 0.30 J 0.47 J 5.5 0.79 J 1.3
<0.28 DUP
Ba 9.7 J 18 73 150 350 5.2 JB 6.5 JB
28 DUP 48 DUP 110 DUP
Be <0.27 <0.27 <0.27 <0.27 5.1 <0.27 <0.27
Cd <0.22 <0.22 <0.22 0.45 J 0.59 J <0.22 <0.22
Co <0.26 <0.26 1.4 21 30 <0.26 <0.26
0.261 DUP
Cr,Total <1.5 <1.5 <1.5 <1.5 85 <1.5 <1.5
Ni <0.52 <0.52 1.2 18 26 <0.52 <0.52
0.791 DUP 14 DUP
Pb <0.17 <0.17 <0.17 <0.17 0.31 J <0.17 <0.17
Se <0.74 <0.74 <0.74 <0.74 <0.74 <0.74 <0.74
TI <0.47 <0.47 <0.47 0.66 J 1.3 <0.47 <0.47
V 7.4 5.2 1.4 2.9 98 20 34
8.4 DUP 1.5 DUP 4.0 DUP 3.5 DUP
(Units:mg/L)
Acidity -20.8 -29.9 -31.9 28 150 <5 -23.0
<5 DUP -54.4 DUP 15 DUP -7.1 DUP -5.54 DUP
Alkalinity 35 41 39 <5 <5 35 36
56 DUP 73 DUP 7.7 DUP
Al 0.30 B 0.17 B <0.016 0.43 12.0 1.60 1.90
0.39 B DUP 0.034 DUP 0.029 JB DUP 0.18 DUP 0.94 DUP 1.70 DUP
Ca 14 23 44 84 150 4.8 3.5
9.4 DUP 33 DUP 5.7 DUP 3.0 DUP
Fe <0.028 0.042 J <0.028 18.0 46.0 0.15 0.73
0.028 J DUP 9.5 DUP 0.48 DUP
K 9.2 9.8 7.9 11.0 16.0 7.6 7.5
8.6 DUP 5.1 DUP 11.0 DUP 8.1 DUP
Li 0.23 0.25 0.22 0.47 0.84 B 0.22 0.26
0.19 DUP 0.10 DUP 0.31 DUP
Mg 1.7 2.6 3.0 5.4 11.0 0.61 0.48J
1.1 DUP 1.9 DUP 3.9 DUP
Mn 0.013 0.056 1.40 2.60 3.20 B 0.0023 J 0.0089
0.0049 J DUP 0.16 DUP 0.71 DUP 0.0061 DUP
Na 4.0 3.9 3.6 4.2 6.7 3.9 5.2
4.0 DUP
P <0.057 <0.057 <0.057 0.12 J 12.0 0.098 J 0.17
Si 2.6 3.1 5.1 14.0 35.0 2.5 4.1
2.2 DUP 2.7 DUP 5.8 DUP
Zn <0.0029 <0.0029 0.0035 0.081 0.23 <0.0029 <0.0029
0.004 J DUP 0.054 DUP
(Units:pH in Standard Units,EC in µS/cm)
pH 8.6 8.1 6.8 5.5 3.6 9.2 9.6
7.7 DUP 7.3 DUP 6.0 DUP
SC 180 470 360 750 1700 87 75
270 DUP 700 DUP 76 DUP
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
Composite#1,#2,and#3 (Waste Rock)
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAF.6
(Note: The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF methods are
not regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various leaching scenarios so that
adverse conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH8 @pH7 @pH5.5 I @pH4 SPLP Natural
(Units:µg/L)
As 0.37J 0.42J 0.52J 1.9 0.511 0.69J
Ba 69 180 470 980 22 27
Be <0.27 <0.27 <0.27 2.4 <0.27 <0.27
Cd <0.22 <0.22 0.30 J 0.70 J <0.22 0.25 J
Cr,Total <1.5 <1.5 <1 s <1.5 <1.5 <1.5
Ni <0.52 <0.52 11 17 <0.52 <0.52
Pb <0.17 <0.17 <0.17 0.26 J <0.17 <0.17
0.241 DUP
Se <0.74 <0.74 <0.74 <0.74 <0.74 <0.74
TI <0.47 0.47 J 0.81 J 1.8 <0.47 <0.47
1.4 DUP
Co <0.26 1.4 44 79 <0.26 <0.26
87 DUP
V 2.5 1.5 1.7 8.9 8.9 5.2
2.2 DUP 2.4 DUP 17 DUP 5.0 DUP 6.8 DUP
(Units:mg/L)
Acidity -21.1 -22.7 12 19 7.8 -14.8
36 DUP -9.71 DUP
Alkalinity 36 31 5 <5 33 36
Al 0.060 <0.016 0.150 3.90 1.10 0.71
Ca 22 36 77 140 7.10 8.60
Fe 0.076 0.055 3.10 22.0 0.570 0.310
<0.028 DUP <0.028 DUP 0.48 DUP
K 8.6 9.50 13.0 15.0 6.50 6.10
Li 0.120 0.120 0.350 0.54 0.084 0.06
0.057 DUP
Mg 3.40 5 6.90 9.60 1.10 1.10
Mn 0.120 1.30 2.90 4.30 0.0078 0.0081
0.012 DUP
Na 3.40 3.40 4.00 4.60 3.50 3.20
P <0.057 <0.057 0.058 J 0.95 <0.057 <0.057
1.5 DUP
Si 3.8 6.60 14.00 56.00 3.70 3.10
28 DUP
Zn 0.0029 J 0.003 J 0.046 0.200 <0.0029 <0.0029
(Units:pH in Standard Units,EC in µS/cm)
pH 7.9 7.0 4.2 9.0 8.7
SC 200 340 630 1200 89 97
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 2: LEAF Method 1313 Screening Results
Concentrator Tailings without By-Products
[Results for Duplicate(DUP)Substantially Similar except as Noted]
LEAF.7
(Note:The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the various LEAF
methods are not regulatory compliance tests,and should not be used as such.Instead,LEAF is intended to help provide information about various
leaching scenarios so that adverse conditions can be avoided via implementation of mitigation strategies.)
pH-controlled screening tests
Parameter @pH8 @pH7 @pH5.5 @pH4 SPLP Natural
(Units:µg/L)
As 0.901 0.96 J 2.1 1.9 0.92 J
O.801 DUP
Ba <3.1 <3.1 3.3 J 18 <3.1 <3.1
Be <0.27 <0.27 1.0 7.3 <0.27 <0.27
8.1 DUP
Cd <0.22 <0.22 0.27 J 0.46 J <0.22 <0.22
Co <0.26 0.27 J 0.48 J <0.26 <0.26
0.63 DUP
Cr,TotaI <1.5 <1.5 <1.5 <1.5 <1.5 1.7J
Ni <0.52 <0.51 3.9 7.1 <0.52 0.57J
Pb 1.2 0.17 0.82 J ^" 1.7
0.991 DUP
Se <0.74 <0.7ti <0.74 <0.74 <0.74 <0.74
TI <0.47 <0.47 <0.47 <0.47 <0.47 <0.47
V 0.86 0.99 J 0.84 J 0.88 J 0.80 J <0.78
<0.78 DUP <0.78 DUP 1.1 DUP 0.85 J DUP
(Units:mg/L)
Acidity <5 <5 8 23 20 14
12 DUP 23 DUP
Alkalinity 7.3 <5 <5 <5 <5 6.8
5.7 DUP
Al 0.460 0.220 0.058 0.490 0.280 0.750
0.340 DUP 0.32 DUP
Ca 1.60 2.00 6.00 11.00 1.70 1.20
Fe 0.077 0.079 0.055 0.440 0.078 0.120
0.054 DUP 0.50 DUP 0.096 DUP 0.11 DUP
K 0.65 0.67 0.76 1.00 0.54 0.54
Li 0.038 0.037 0.098 0.190 0.028 0.036
Mg 0.1601 0.22 J 0.35 J 0.43 0.18 J 0.111
Mn 0.026 0.078 0.820 1.700 0.044 0.017
1.90 DUP
Na 1.40 1.30 1.40 1.60 1.60 1.30
P 0.071 J 0.160 J 0.910 2.50 0.077 J 0.066 J
Si 1.60 1.40 1.80 2.40 1.70 2.00
Zn 0.00461 0.005 0.049 0.110 0.0036 J 0.00411
(Units:pH in Standard Units,EC in µS/cm)
pH 8.3 4.2 7.7 9.0
LSE
18 52 55 130 20
*Calibration Blank Outside Acceptance Limits
J -Approximate value,greater than Method Detection Limit but less than Reporting Limit.
B-Compound found in both blank and sample.

Piedmont Lithium
Attachment 3: Summary of 2019 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
Waste Rock 205-7
HC.1
Leachate Week of Peak Final Week
Parameter Concentration Range I Concentration Concentration
(Units:µg/L)
Hg ND(<0.01) - 0.01 15 ND(<0.01)
Ag ND(<0.05)µg/L throughout
As ND(<0.2) - 0.2 0 ND(<O.2)
B ND(<2) 4 1 ND(<2)
Ba 0.22 - 0.7 0 0.22
Be ND(<0.007) 0.008 3 ND(<0.007)
Bi ND(<0.007)µg/L throughout
Cd ND(<0.003) 0.015 5 0.009
Co ND(<0.004) - 0.025 15 ND(<0.004)
Cr ND(<0.08)µg/L throughout
Cu ND(<0.2) 0.5 0 0.15
Mo 0.95 12.4 5 9.11
Ni ND(<0.1) 0.2 1 0.1
Pb ND(<0.01) - 0.06 1 0.03
Sb ND(<0.9)µg/L throughout
Se ND(<0.04) - 0.15 0 ND(<0.04)
Sn ND(<0.06) 0.25 0 ND(<0.06)
Sr 3.63 6.24 0 3.82
Ti ND(<0.05) 0.24 0 0.20
Th ND(<0.1) - 0.9 1 ND(<0.1)
TI ND(<0.005) 0.023 0 ND(<0.005)
U 0.031 - 0.272 20 0.272
V 0.3 1.99 0 0.40
W ND(<0.02) - 0.19 0 ND(<0.02)
Y ND(<0.002) 0.008 0 0.004
Zr ND(<2)µg/L throughout
(Units:mg/L)
Al 0.057 0.111 0 0.067
Fe ND(<0.007) - 0.007 0 ND(<0.007)
K 0.13 1.8 0 0.130
Li 0.0095 0.317 0 0.0095
Mg 0.177 0.242 15 0.190
Mn 0.00110 0.00524 2 0.00340
Na 0.16 2.28 0 0.16
P ND(<0.003) 0.016 20 0.016
Si 0.38 0.47 1 0.43
Zn ND(<0.002)mg/L throughout
SO4 ND(<0.2) 0.5 0 ND(<0.2)
F
Chloride
Ca Not analyzed
NO3 Not analyzed
Acidity ND(<2)mg/L throughout
Alkalinity 9 22 1 0 1 11
Hardness I I Not analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.98 8.01 0 7.15
EC 20 - 44 0 1 22

Piedmont Lithium
Attachment 3: Summary of 2019 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
Waste Rock 212-6
HC.2
Leachate Week of Peak Final Week
Parameter Concentration Range I Concentration Concentration
(Units:µg/L)
Hg ND(<0.01)µg/L throughout
Ag ND(<0.05)µg/L throughout
As 0.3 1.1 0 0.3
B ND(<2) 4 1 ND(<2)
Ba 0.61 - 3.38 0 0.61
Be ND(<0.007) 0.013 3 ND(<0.007)
Bi ND(<0.007) - 0.008 1 ND(<0.007)
Cd ND(<0.003) 0.010 3 ND(<0.003)
Co 0.013 0.048 0 0.030
Cr ND(<0.08) 0.19 20 0.19
Cu ND(<0.2) 2 15 ND(<0.2)
Mo 1.61 - 20.5 3 5.36
Ni ND(<0.1) 0.6 1 0 1 0.1
Pb ND(<0.01) - 0.13 1 1 0.01
Sb ND(<0.9)µg/L throughout
Se ND(<0.04) - 0.42 0 ND(<0.04)
Sn ND(<0.06) 0.2 3 ND(<0.06)
Sr 8.32 - 15.7 0 9.27
Ti 0.08 0.38 1 0.08
Th ND(<0.1) - 0.3 2 ND(<0.1)
TI 0.011 0.069 0 0.011
U 0.015 3.47 5 0.204
V 0.14 0.59 0 0.20
W ND(<0.02) - 0.19 1 ND(<0.02)
Y ND(<0.002) 0.014 20 0.014
Zr ND(<2)µg/L throughout
(Units:mg/L)
Al 0.059 0.094 10 0.061
Fe ND(<0.007) - 0.008 1 ND(<0.007)
K 0.424 7.89 0 0.424
Li 0.0171 - 0.589 0 0.0171
Mg 0.422 0.784 5 0.422
Mn 0.00227 - 0.00637 3 0.00321
Na 0.08 2.13 0 0.09
P ND(<0.003) 0.012 20 0.012
Si 0.52 0.66 5 0.55
Zn ND(<0.002)mg/L throughout
SO4 1.9 6.2 0 2.4
F
Chloride
Ca Not analyzed
NO3 Not analyzed
Acidity ND(<2)mg/L throughout
Alkalinity 10 24 1 0 1 11
Hardness I I Not analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 7.07 7.77 0 7.10
EC 27 - 82 0 1 31

Piedmont Lithium
Attachment 3: Summary of 2019 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
Tailings 4(Concentrator Tailings without By-Products)
HC.3
Leachate Week of Peak Final Week
Parameter Concentration Range I Concentration Concentration
(Units:µg/L)
Hg ND(<0.01) - 0.01 1 5 ND(<0.01)
Ag ND(<0.05)µg/L throughout
As 0.4 - 1.3 1 0.4
B ND(<2) 9 1 ND(<2)
Ba 0.25 2.76 3 0.92
Be 0.009 0.034 20 0.034
Bi ND(<0.007) - 0.017 0 ND(<0.007)
Cd ND(<0.003) 0.032 1 0.009
Co ND(<0.004) - 0.027 0 ND(<0.004)
Cr ND(<0.08) 0.66 2 ND(<0.08)
Cu ND(<0.2) 3 0 ND(<0.2)
Mo 0.24 - 26.5 5 0.31
Ni ND(<0.1) 0.3 0 ND(<O.1)
Pb 0.01 - 0.16 1 0.04
Sb ND(<0.9) 1.1 2 ND(<0.9)
Se ND(<0.04) - 0.05 0 ND(<0.04)
Sn 0.11 0.43 0 0.13
Sr 1.59 11.9 2 2.03
Ti ND(<0.05) 0.19 1 ND(<0.05)
Th ND(<0.01) - 0.1 2 ND(<0.01)
TI 0.006 0.048 1 0.006
u 0.046 12.2 1 0.046
V 0.16 0.47 1 0.16
w ND(<0.02) - 0.25 1 ND(<0.02)
y ND(<0.002) 0.011 5 0.003
Zr ND(<2)µg/L throughout
(Units:mg/L)
Al 0.007 0.55 1 0 0.007
Fe ND(<0.007)mg/L throughout
K 0.077 1.12 1 0.119
Li 0.0093 0.135 2 0.0118
Mg 0.043 0.448 2 0.043
Mn 0.0005 0.0219 20 0.0219
Na 0.07 5.35 1 0.11
P 0.034 - 0.131 20 0.131
Si 0.47 1.76 2 0.68
Zn ND(<0.002) - 0.004 0 0.003
SO4 ND(<0.2) 1.4 0 ND(<0.2)
F
Chloride
Ca Not analyzed
NO3 Not analyzed
Acidity ND(<2) - 2 15 ND(<2)
Alkalinity 2 21 2 2
Hardness Not analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.34 7.27 5 6.34
EC 4 - 42 1 1 5

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
20-350-ABA8(Schist)
H C.4
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 20) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 1.2 - 7.3 20 7.3
B <2 6 2 <2
Ba 0.32 - 1.06 0.32
Be <0.007 N/A <0.00
Bi <0.01 - 0.05 2 <0.01 Detected only once
Cd <0.003 0.011 1 <0.003 Detected only twice
Co 0.039 0.233 1 0.058
Cr <0.08 0.14 20 0.14
Cu <0.2 2.2 0 <0.2
Mo 0.11 - 5.05 1 0.23
Ni 0.2 2.7 0 0.2
Pb <0.09 0.15 4 <0.09
Sb <0.9 N/A <0.9
Se 0.08 - 0.42 0 0.11
Sn <0.06 0.24 0 <0.06
Sr 4.87 - 14 1 4.87
Ti 0.16 1.38 0 0.31
Th <0.1 N/A <0.1
TI <0.005 - 0.055 2 <0.005
U 0.213 0.743 1 0.301
V 0.52 0.71 0 0.53
W 0.06 - 0.65 0 0.06
Y <0.2 0.11 0 <0.02 Detected only twice
Zr <2 N/A <2
(Units:mg/L)
Al 0.029 - 0.065 0 0.029
Fe <0.007 0.017 0 0.007
K 0.562 - 3.94 1 0.562
Li 0.016 0.230 1 0.016
Mg 0.260 0.578 1 0.294
Mn 0.00261 0.0086 0 0.00261
Na 0.14 - 6.24 1 0.14
P <0.003 0.013 20 0.013
Si 0.26 - 0.38 4 0.28
Zn <2 N/A <2
SO4 5 - 38 1 5 Static
F - - Not Analyzed
Chloride Not Analyzed
Ca Not Analyzed
NO3 - - Not Analyzed
Acidity <2 N/A <2
Alkalinity 4 - 13 0 5 Static
Hardness Not Analyzed
(Units:pH in Standard Units,EC in MS/cm)
pH 6.91 - 8.32 1 0 7.2 Static
EC 1 25 102 1 1 25 Static

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
20-363-ABA6(Mudstone)
H C.5
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 20) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 0.5 - 2.1 15 1
B <2 4 2 <2
Ba 0.13 0.82 1 0.13
Be <0.007 0.009 2 <0.007 Detected only once
Bi <0.01 N/A <0.01
Cd <0.003 - 0.015 2 <0.003
Co 0.090 0.0149 3 0.1
Cr <0.08 0.12 N/A 0.12 Detected only once
Cu <0.2 0.4 0&1 <0.2
Mo 0.06 - 4.37 3 0.06
Ni 0.3 1.7 0 0.3
Pb <0.09 0.3 1 <0.09 Detected only twice
Sb <0.9 N/A 0.04
Se <0.04 - 0.24 0 0.04
Sn <0.06 0.33 0 <0.06
Sr 11.3 32.2 2 11.3
Ti 0.11 1.35 5 0.27
Th <0.1 - 0.1 1 <0.1 Detected only once
TI <0.005 0.033 2 <0.005
U 0.075 0.699 2 0.243
V 0.47 1.3 3 0.47
W <0.02 - 0.67 0 <0.02
Y <0.02 N/A <0.02
Zr <2 N/A <2
(Units:mg/L)
Al 0.018 - 0.085 1 0.021
Fe <0.007 0.012 1 <0.007
K 0.098 0.606 0 0.08
Li 0.0185 0.220 2 0.0185
Mg 0.0406 - 0.922 3 0.406
Mn 0.00512 0.0192 2 0.00512
Na 0.08 1.64 0 0.08
P <0.003 0.059 1 0.011
Si 0.25 0.53 2 0.25
Zn <0.002 0.013 1 <0.002 Detected only twice
SO4 11 - 21 7&8 12 Static
F - Not Analyzed
Chloride - - Not Analyzed
Ca 5.57 8.98 2 5.57
NO3 - - Not Analyzed
Acidity <2 N/A <2
Alkalinity 3 - 16 1 2 1 5 Static
Hardness - Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.86 - 7.88 1 1 7.18
EC 1 41 - 69 1 2 1 48

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
21-408-ABA5 (Schist)
H C.6
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 20) Comments
(Units:µg/L)
Hg <0.01 N/A <0.1
Ag <0.05 N/A <0.05
As 1.3 - 5.6 15 4.1
B <2 7 1&2 <2
Ba 0.39 1.09 0 0.39
Be <0.007 0.017 0&1 <0.007
Bi <0.01 - 0.04 2 <0.01 Detected only once
Cd <0.003 0.008 2 0.003
Co 0.050 0.181 0 0.095
Cr <0.08 0.10 15&20 0.10
Cu <0.2 1.1 0 0.3
Mo 0.20 4.78 1 0.33
Ni 0.3 4.5 0 0.3
Pb <0.09 N/A <0.09
Sb <0.9 N/A <0.9
Se 0.06 - 0.6 0 0.06
Sn <0.06 0.28 0 <0.06
Sr 12.6 30 0 12.6
Ti <0.005 0.72 0 0.07
Th <0.1 N/A <0.1
TI <0.005 - 0.034 0 <0.005
U 0.699 1.85 2 0.716
V 0.13 0.33 0 0.13
W 0.05 0.9 0 0.05
Y <0.02 0.05 0 <0.02 Detected only once
Zr <2 N/A <2
(Units:mg/L)
Al 0.025 - 0.066 0 0.05
Fe <0.007 0.013 0 <0.007 Detected only once
K 0.467 - 4.27 0 0.467
Li 0.0062 0.108 1 0.002
Mg 0.240 0.670 0 0.24
Mn 0.0073 0.0193 0 0.0175
Na 0.05 5.08 0 0.05
P <0.003 0.008 0,1,&20 0.008
Si 0.28 0.45 0 0.28
Zn <0.002 0.003 2 <0.002 Detected only once
SO4 12 - 26 0&1 16 Static
F - Not Analyzed
Chloride Not Analyzed
Ca Not Analyzed
NO3 - Not Analyzed
Acidity <2 N/A <2
Alkalinity <2 - 20 1 0 1 <2 Static
Hardness - Not Analyzed
(Units:pH in Standard Units,EC in MS/cm)
pH 6.86 - 7.96 1 1 7.12 1 Static
EC 1 14 105 1 1 14

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
21-408-ABA6(Amphibolite)
H C.7
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 20) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 0.9 - 3.5 15 3.2
B <2 3 0&2 <2
Ba 0.34 - 0.47 1&3 0.35
Be <0.007 0.013 2 <0.007 Detected only once
Bi <0.01 N/A <0.01
Cd <0.003 - 0.006 1 <0.03
Co 0.074 - 0.226 0 0.158
Cr <0.08 0.13 2 0.08
Cu <0.2 0.7 0 0.3
Mo 0.11 - 1.36 1 0.36
Ni 0.4 4.7 0 0.5
Pb <0.09 N/A <0.09
Sb <0.9 N/A <0.9
Se <0.04 - 0.21 0 <0.04
Sn <0.06 0.22 0 <0.06
Sr 5.78 24.7 0 5.78
Ti 0.14 0.53 1 0.14
Th <0.1 n/a <0.1
TI <0.005 - 0.019 20 <0.005
U 0.009 0.032 10 0.01
V 0.39 0.58 0&2 0.39
W 0.24 - 9.78 2 0.24
Y <0.02 N/A <0.02
Zr <2 N/A <2
(Units:mg/L)
Al 0.027 - 0.052 0 0.027
Fe <0.007 0.01 2 <0.007 Detected only twice
K 0.447 - 0.912 0 0.56
Li 0.0084 0.0406 2 0.0084
Mg 0.182 - 0.588 0 0.182
Mn 0.00123 0.00604 0 0.00123
Na 0.19 1.65 0 0.19
P <0.003 0.018 20 0.018 Detected only once
Si 0.26 - 0.39 3 0.27
Zn <0.002 0.002 20 0.002
SO4 3 15 0 3 Static
F - - Not Analyzed
Chloride Not Analyzed
Ca 2.10 7.60 0 2.22
NO3 - - Not Analyzed
Acidity <2 3 4 <2
Alkalinity <2 - 13 1 <2 Static
Hardness Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.50 - 7.71 1 1 6.77
EC 1 16 61 1 0 1 16

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
21-408-ABA11(Amphibolite)
H C.8
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 20) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 1.5 - 6.5 20 6.5
B <2 3 2&3 <2
Ba 0.1 - 0.24 0 0.13
Be <0.007 0.015 2 <0.007 Detected only once
Bi <0.01 N/A <0.01
Cd <0.003 - 0.009 5 <0.003 Detected only twice
Co 0.016 - 0.068 0 0.19
Cr <0.08 0.15 0 0.1
Cu <0.2 1.2 0 <0.2
Mo 0.11 - 2.73 1 0.22
Ni <0.1 0.8 0 <0.1
Pb <0.09 N/A <0.09
Sb <0.9 N/A <0.9
Se <0.04 - 0.12 0 <0.04
Sn <0.06 0.34 0 <0.06
Sr 9.01 - 19.3 0 9.01
Ti 0.14 3.1 0 0.14
Th <0.1 N/A <0.1
TI <0.005 - 0.008 2 <0.005 Detected only once
U 0.015 0.035 4 0.02
V 1.28 2.05 0 1.28
W 0.05 0.64 0 0.05
Y <0.02 N/A <0.02
Zr <2 N/A <2
(Units:mg/L)
Al 0.036 - 0.107 0 0.052
Fe <0.007 0.029 0 <0.007
K 0.132 - 0.705 0 0.159
Li 0.0071 0.0561 1 0.0071
Mg 0.241 - 0.369 0 0.259
Mn 0.00181 0.00469 1 0.00181
Na 0.09 3.32 0 0.09
P <0.003 0.015 20 0.015
Si 0.33 0.48 0&3 0.35
Zn <0.002 N/A <0.002
SO4 <2 - 3 1&2 <2
F - Not Analyzed
Chloride Not Analyzed
Ca Not Analyzed
NO3 - - Not Analyzed
Acidity <2 N/A <2
Alkalinity 5 - 22 0 8
Hardness Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 1 7.33 8.95 1 1 7.45 1 Below 8 at week 1
EC 1 18 52 1 0 1 20

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 20 Weeks)
21-408-ABA13 (Mudstone)
H C.9
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 20) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 4.1 - 24.2 15 22.7
B <2 23 2 <2
Ba 0.14 - 0.65 2 0.14
Be <0.007 0.074 2 <0.007
Bi <0.01 - 0.1 2 <0.01
Cd <0.003 0.080 2 0.003
Co 0.028 0.2 2 0.05
Cr <0.08 0.19 2 0.08
Cu <0.2 0.7 0 <0.2
Mo 0.08 0.8 10 0.18
Ni 0.1 0.7 0 0.1
Pb <0.09 0.44 2 <0.09
Sb <0.9 1.1 2 <0.9 Detected only once
Se <0.04 - 0.36 2 0.05
Sn <0.06 0.43 0 <0.06
Sr 16.5 26.6 0 17.4
Ti 0.1 0.95 2 0.12
Th <0.1 N/A <0.1
TI <0.005 - 0.15 2 <0.005 Detected only once
U 0.012 - 0.071 15 0.050
V 0.7 1.64 1 0.70
W 0.27 - 3.9 0 0.27
y <0.02 0.02 2 <0.02 Detected only once
Zr <2 N/A <2
(Units:mg/L)
Al 0.027 - 0.063 0 0.028
Fe <0.007 0.02 2 <0.007
K 0.048 0.31 0 0.074
Li 0.0295 0.471 0 0.0295
Mg 0.019 0.333 0 0.325
Mn 0.00147 0.00439 4 0.00249
Na 0.12 - 4.93 0 0.12
P <0.003 0.018 20 0.018
Si 0.34 - 0.45 3 0.34
Zn <0.002 0.012 2 <0.002
SO4 5 12 0&20 7
F - Not Analyze
Chloride Not Analyze
Ca Not Analyze
NO3 - Not Analyze
Acidity <2 N/A <2
Alkalinity 7 - 30 1 0 1 8 Static
Hardness - Not Analyze
(Units:pH in Standard Units,EC in µS/cm)
pH 1 7.18 8.97 1 1 7.S7
EC 1 32 71 1 0 1 34 1 Below 50 after week 0

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 25 Weeks)
20-350-ABA6(Schist)
HC.10
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 25) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 0.4 - 1.4 15 0.6 Elem.An.140 µg/g
B <2 12 4 <2
Ba 0.36 - 1.29 0 0.39
Be <0.007 0.012 2 0.011
Bi <0.01 N/A <0.01
Cd 0.003 - 0.026 20 0.026
Co 0.513 5.39 0 1.33
Cr <0.08 0.13 1 <0.08
Cu <0.2 1.9 0 <0.2
MO 0.06 - 0.34 1 0.22
Ni 3.2 49.2 0 5.3
Pb <0.09 0.15 0 <0.09 Detected only in week 0
Sb <0.9 N/A <0.9
Se 0.26 - 1.16 1 0.33
Sn <0.06 0.29 0 <0.06
Sr 15.2 - 56.7 1 15.2
Ti <0.05 0.12 1 <0.05
Th <0.1 - 0.1 5 <0.1 Detected only once
TI <0.005 0.017 2 <0.005
U 0.119 0.506 2 0.119
V <0.01 0.08 2&3 <0.01
W <0.02 - 0.16 1 <0.02
Y <0.02 3 0 <0.02
Zr <2 N/A <2
(Units:mg/L)
Al 0.008 0.038 3 0.008
Fe <0.007 0.104 15 0.021
K 0.302 - 3.72 0 0.302
Li 0.0054 0.0365 1 0.0054
Mg 0.263 2.32 1 0.263
Mn 0.0173 0.0735 15 0.0641
Na 0.07 - 3.73 0 0.07
P <0.003 0.006 20 <0.003
Si 0.27 - 0.48 3 0.27
Zn <0.002 0.008 15 0.003
SO4 37 - 87 1 37
F - - Not Analyzed
Chloride - - Not Analyzed
Ca 15.8 31.4 2 15.8
NO3 - - Not Analyzed
Acidity <2 7 1 <2
Alkalinity 3 12 1 0 2
Hardness I - - Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.58 7.45 1 1 6.7
EC 1 94 207 1 1 1 98

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 25 Weeks)
20-350-ABA12(Amphibolite)
HC.11
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 25) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 1.2 - 2.2 15 1.6 Elem.An.2.2 µg/g
B <2 4 2 <2
Ba 0.15 0.49 15 0.17
Be <0.007 0.008 2 <0.007
Bi <0.01 N/A <0.01
Cd <0.003 - 0.007 0 0.004
Co 0.044 - 0.108 0 0.086
Cr <0.08 0.15 2 <0.08
Cu <0.2 1.5 0 0.2
Mo 0.08 4.62 3 0.16
Ni 0.1 0.6 0 0.1
Pb <0.09 0.11 20 <0.09
Sb <0.9 N/A <0.9
Se <0.04 - 0.13 0 <0.04
Sn <0.06 0.2 0 <0.06
Sr 5.69 15 1 7.97
Ti 0.05 3.12 0 0.05
Th <0.1 N/A <0.1
TI <0.005 - 0.011 2 <0.005
U 0.009 0.068 15 0.009
V 0.30 3.48 0 0.30
W 0.04 - 1.56 2 0.04
Y <0.02 N/A <0.02
Zr <2 N/A <2
(Units:mg/L)
Al 0.028 - 0.12 0 0.028
Fe <0.007 0.04 0 <0.007
K 0.074 - 0.509 0 0.039
Li 0.0109 0.371 0 0.0109
Mg 0.141 - 0.377 20 0.207
Mn 0.00146 0.00315 3 0.00161
Na 0.05 6.22 0 0.05
P <0.003 0.023 20 <0.003
Si 0.21 - 0.52 0 0.21
Zn <0.002 0.003 10 <0.002 Detected only once
SO4 3 13 18 9
F - - Not Analyzed
Chloride - - Not Analyzed
Ca 2.03 5.31 15 4.26
NO3 - - Not Analyzed
Acidity <2 N/A <2
Alkalinity 3 - 16 0 6
Hardness Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.87 - 9.12 1 1 6.93 Exceeded 8.5 only in week 0
EC 1 23 52 1 0 1 27

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 25 Weeks)
21-408-ABA14 (Schist)
HC.12
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 25) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 N/A <0.05
As 0.2 - 0.5 1 0.2 Elem.An.5.7 µg/g
B <2 4 2&3 <2
Ba 0.28 0.67 20 0.28
Be <0.007 0.026 1 <0.007
Bi <0.01 - 0.01 0 <0.01 Detected only once
Cd <0.003 0.022 2 0.007
Co 0.019 0.064 2 0.035
Cr <0.08 0.13 20 <0.08
Cu <0.2 0.8 0 <0.2
MO 0.19 22.4 3 0.19
Ni <0.1 0.7 5 <0.1
Pb <0.09 N/A <0.09
Sb <0.9 N/A <0.9
Se 0.06 - 0.28 0 0.07
Sn <0.06 0.28 0 <0.06
Sr 9.30 20.0 15 14.9
Ti 0.09 0.89 1 0.14
Th <0.1 - 0.2 1 <0.1 Detected only once
TI <0.005 0.013 2 0.005
U 0.040 0.977 15 0.687
V 0.29 0.98 0 0.29
W 0.03 1.5 0 0.03
Y <0.02 N/A <0.02
Zr <2 N/A <2
(Units:mg/L)
Al 0.031 - 0.094 0 0.031
Fe <0.007 - 0.011 2 <0.007
K 0.427 - 4.83 0 0.427
Li 0.0096 0.344 2 0.0096
Mg 0.215 0.528 10 0.243
Mn 0.00209 0.00555 15 0.00442
Na 0.03 5.26 0 0.03
P <0.003 0.012 0 <0.003
Si 0.28 0.43 3 0.28
Zn <0.002 - 0.007 15 <0.002 Detected only once
SO4 10 21 13 17
F - - Not Analyzed
Chloride - - Not Analyzed
Ca 2.89 8.53 15 7.65
NO3 - - Not Analyzed
Acidity <2 N/A <2
Alkalinity 4 - 21 1 1 1 5
Hardness Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 6.84 - 8.69 1 1 7.00
EC 1 37 69 1 0 1 48

Piedmont Lithium
Attachment 3: Summary of 2021-2022 Humidity Cell
(ASTM D5744-96[reapproved 2001])Leaching Results
(Leached for 30 Weeks)
21-408-ABA9(Schist)
HC.13
Leachate Final Week
Concentration Week of Peak Concentration
Parameter Range Concentration (Week 30) Comments
(Units:µg/L)
Hg <0.01 N/A <0.01
Ag <0.05 - 0.07 0 <0.05 Detected only in week 1
As <0.2 - 1.0 15 0.2 El.An: 20 µg/g
B <2 5 3 <2
Ba 0.47 - 1.55 0 0.52
Be <0.007 N/A <0.007
Bi <0.01 N/A <0.01
Cd <0.003 - 0.007 2,5,15,&20 0.005
Co 0.139 0.561 0 0.505
Cr <0.08 0.6 0&5 <0.08
Cu <0.2 0.6 0&5 <0.2
Mo 0.10 4.13 25 0.13
Ni 0.5 5.2 0 4.2
Pb <0.09 0.16 1 <0.09
Sb <0.9 N/A <0.9
Se 0.08 - 1.09 0 0.08
Sn <0.06 0.29 0 <0.06
Sr 12.5 45.9 0 12.5
Ti <0.05 0.4 4 <0.05
Th <0.1 N/A <0.1
TI <0.005 - 0.015 0&2 <0.005
U 0.152 - 1.091 2 0.228
V 0.03 0.14 4&20 0.03
W <0.02 - 0.3 0 <0.02
y <0.02 0.03 0 <0.02 Detected only once
Zr <2 N/A <2
(Units:mg/L)
Al 0.009 - 0.055 3 0.009
Fe <0.007 N/A <0.007
K 0.729 - 8.00 0 0.729
Li 0.0115 0.123 0 0.0133
Mg 0.19 1.82 0 0.19
Mn 0.0128 0.0897 30 0.0897
Na 0.04 - 4.96 0 0.06
P <0.003 0.010 20 <0.003
Si 0.29 0.62 3 0.32
Zn <0.002 0.005 15 <0.002
SO4 31 - 68 0 35
F - - Not Analyzed
Chloride - - Not Analyzed
Ca 12.1 25.6 0 12.1
NO3 - - Not Analyzed
Acidity <2 9 1 <2 Detectable in weeks 1 and 2
Alkalinity 2 - 20 0 3 Below 10 by week 1
Hardness Not Analyzed
(Units:pH in Standard Units,EC in µS/cm)
pH 1 6.79 7.62 1 1 6.95
EC 1 76 199 1 0 1 82

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Piedmont Lithium
Attachment 4: LEAF Test Results Re: V,Al, As and pH under "natural" leachate conditions
(Note: The LEAF How-To Guide(May 2019)issued by the United States Environmental Protection Agency(US EPA)establishes that the
various LEAF methods are not regulatory compliance tests, and should not be used as such. Instead, LEAF is intended to help provide
information about various leaching scenarios so that adverse conditions can be avoided via implementation of mitigation strategies.)
V Al As
Concentration Concentration Concentration
Sample ID and Description (µg/L) (µg/L) (µg/L) pH
LEAFA PAG Composite 20 1.50 8.9 - 15 9.8
LEAF.2 non-PAG/PAG/Concentrator Tailings with By-Products 23 - 36 1.4 - 1.6 2.7 - 6.8 9.3-9.6
LEAF.3 PAG/Concentrator Tailings with By-Products 27 1.7 - 2.3 29 - 32 9.6
LEAF.4 Sample 1-Concentrator Tailings with By-Products 2.7 - 3.6 0.65 - 0.71 2.3 8.9
LEAFS non-PAG/Concentrator Tailings with By-Products 34 1.7 - 1.9 1.3 9.6
LEAF.6 Composite#1,#2,and#3(Waste Rock) 5.2 - 6.8 0.71 0.69J 8.7
LEAF.7 Concentrator Tailings without By-Products <0.78 - 0.95.1 0.75 0.92.1 9.0

Piedmont Lithium
Attachment 5: Duration of Elevated pH Relative to Regulatory Standards in Humidity Cell Tests
Test Week in Week in
Sample Duration pH which pH which pH
Material ID (weeks) Range falls below 9 falls below 8.5 Note
2017-2018 Waste Rock Waste Rock 205-7 20 6.98 - 8.01 N/A N/A
2017-2018 Waste Rock Waste Rock 212-6 20 7.07 - 7.77 N/A N/A
Concentrator Tailings Tailings 4 20 6.34 - 7.27 N/A N/A
Schist 20-350-ABA8 20 6.91 - 8.32 N/A N/A
Schist 21-408-ABA5 20 6.86 - 7.96 N/A N/A
Schist 20-350-ABA6 25 6.58 - 7.45 N/A N/A
Schist 21-408-ABA14 25 6.84 - 8.69 N/A Week 1 Was 8.69 in Week 0;8.45 in Week 1
Schist 21-408-ABA9 30 6.79 - 7.62 N/A N/A
Mudstone 20-363-ABA6 20 6.86 - 7.88 N/A N/A
Mudstone 21-408-ABA13 20 7.18 - 8.97 N/A Week 1 Was 8.97 in Week 0;8.42 in Week 1
Amphibolite 21-408-ABA6 20 6.50 - 7.71 N/A N/A
Amphibolite 21-408-ABA11 20 7.33 - 8.95 N/A Week 1 Was 8.95 in Week 0;7.83 in Week 1
Amphibolite 20-350-ABA12 25 6.87 - 9.12 Week 1 Week 1 Was 9.2 in Week 0; 8.22 in Week 1

Piedmont Lithium
Attachment 6: Humidity Cell Test Results Re:V,Al, and pH
Test V Week Al pH when Week when
Sample Duration pH (µg/L) pH when when (mg/L) Al>0.3 Al>0.3
Material ID (weeks) Range Range V>7 µg/L V>7 µg/L Range mg/L mg/L
2017-2018 Waste Rock Waste Rock 205-7 20 6.98 8.01 0.30 1.99 N/A N/A 0.057 0.111 N/A N/A
2017-2018 Waste Rock Waste Rock 212-6 20 7.07 7.77 0.14 0.59 N/A N/A 0.059 0.094 N/A N/A
Concentrator Tailings Tailings 4 20 6.34 7.27 0.16 0.47 N/A N/A 0.007 0.55 7.21 1
Schist 20-350-ABA8 20 6.91 8.32 0.52 0.71 N/A N/A 0.029 0.065 N/A N/A
Schist 21-408-ABA5 20 6.86 7.96 0.13 0.33 N/A N/A 0.025 0.066 N/A N/A
Schist 20-350-ABA6 25 6.58 7.45 <0.01 0.08 N/A N/A 0.008 0.038 N/A N/A
Schist 21-408-ABA14 25 6.84 8.69 0.29 0.98 N/A N/A 0.031 0.094 N/A N/A
Schist 21-408-ABA9 30 6.79 7.62 0.03 0.14 N/A N/A 0.009 0.055 N/A N/A
Mudstone 20-363-ABA6 20 6.86 7.88 0.47 1.3 N/A N/A 0.018 0.085 N/A N/A
Mudstone 21-408-ABA13 20 7.18 8.97 0.7 1.64 N/A N/A 0.027 0.063 N/A N/A
Amphibolite 21-408-ABA6 20 6.50 7.71 0.39 0.58 N/A N/A 0.027 0.052 N/A N/A
Amphibolite 21-408-ABA11 20 7.33 8.95 1.28 2.05 N/A N/A 0.036 0.107 N/A N/A
Amphibolite 20-350-ABA12 25 6.87 9.12 0.30 3.48 N/A N/A 0.028 0.12 N/A N/A

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Piedmont Lithium
Attachment 7: Summary of Elevated Parameters in Humidity Cell Test Results
Sample Duration of Elevated Standard
Material ID Parameter Concentration Exceeded Comment
2017-2018 Waste Rock 2 Samples, No Instances of Elevated Parameters
Concentrator Tailings 1 Sample, No Instances of Elevated Parameters
Schist 20-350-ABA8 None
21-408-ABA5 None
20-350-ABA6 Co Week 0-1 and 10-25 NCGW
21-408-ABA14 pH Week 0 NCGW Week 0 pH =8.69
21-408-ABA9 None
Mudstone 20-363-ABA6 None
21-408-ABA13 As Week 1-20(duration) DW, NCGW
Sb Week 2 NCGW Detected only once
pH Week 0 NCGW Week 0 pH =8.97
Amphibolite 21-408-ABA6 None
21-408-ABA11 JpH I Week 0 NCGW Week 0 pH =8.95
20-350-ABA12 JpH I Week 0 NCGW ]Week 0 pH =9.12
Notes RE: Humidity Cell Test Results
>V: while indicated to be a potential COPC in LEAF M.1313 tests as a result of highly-elevated pH,V in Humidity Cells shows no
exceedences of a standard at any time.
>Al: while indicated to be a potential COPC in LEAF M.1313 tests as a result of highly-elevated pH,Al in Humidity Cells shows no
exceedences of a standard at any time.
>As: can exceed the DW standard and NCGW standard for extended periods in the mudstone.
>Co: exceeded the NCGW standard in only one sample(a schist),and did so fairly persistently but at only low-level exceedences.
>pH: slightly exceeded a standard in 4 of 13 samples, but quickly declined to within standards.

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Exhibits
HkLLNNLLER

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P I E DAAO N T Stream and Wetlands
LITHIUM
Conceptual Reclamation
Flow Diagram Onsite Lithium
Treatment Hydroxide
Product Pit Discharge
t Ponds
Offsite Waste Water
Water
Treatment
Facility
Pit Discharge
Ponds
Conversion Plant Active Open Pit
Ore
Ore
Conversion Plant
Tailings Concentrator Plant Concentrator
Tailings Plant
Water
Waste Rock
Disposal
Facility ZAbove-ground Waste Rock
Waste Rock
Disposal Area I
7
Water I Fully Excavated
Concentrator Plant Tailings Open Pit (to be
backfilled)
Sediment
Control Ponds
o Monitoring Point
Stream and Wetlands
Exhibit 1

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CONCEPTUAL DIAGRAM OF
WATER COLLECTION AND
MONITORING SYSTEM IN
BACKFILLED PIT
WATER COLLECTION AND
MONITORING SYSTEM
ORIGINAL (DESIGN TBD) ORIGINAL
GROUND GROUND
COMPLETED
PIT
Q �BACKFILL
ROCK ROCK
O O
WATER COLLECTION AND WATER COLLECTION AND
MONITORING SYSTEM MONITORING SYSTEM
(DESIGN TBD) ORIGINAL (DESIGN TBD) ORIGINAL
GROUND GROUND
AB VE-GROUNDi
♦Y WASTE ♦1
iiFtt♦ C PI iii
? �BACKFILLBACKFILL�
ROCK ROCK?
O O
WATER COLLECTION AND
MONITORING SYSTEM
(DESIGN TBD) ORIGINAL
TEMPORARYABOVE-GROUND GROUND
TREATMENT ����.♦ BR WATT LE
*IF NECESSARY, WATER COLLECTION AND MONITORING
¢ SYSTEM CAN BE PUMPED TO CREATE"REVERSE
BACKFILL GRADIENT"CONDITIONS TO TEMPORARILY FACILITATE pH
MITIGATION CONTROL.
Y ROCKY ,
O
Exhibit 2

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