Appendix C Response to DWR-WQPS Comments

Piedmont Lithium Carolinas, Inc. I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
Updates shown in red
Comments on Carolina Lithium Project by DWR-WQPS
January 14. 2022
1. Chemical Processing Wastewater: The Application in section C.3.d. reflects industrial
process wastewater from chemical operations will be discharged to a Publicly Owned
Treatment Works (POTW) with pretreatment. Thank you for providing the requested details
concerning MGD to the Long Creek WWTP. However, we still request submission of
detailed chemical analysis or characterization of the wastewater. This is necessary for DWR
to determine if the selected POTW has sufficient capacity to manage not only the flow
volume, but the anticipated pollutant load under our rules 15A NCAC 02H section .0900.
Since these comments were received, two Technical Memorandums were issued characterizing
the projected flows and constituent loads for the Carolina Lithium project that are proposed to be
sent to Long Creek WWTP. Please see Attachment 1 for the February 22, 2022 Technical
Memorandum titled Wastewater Treatment Plant Considerations Update and the November 9,
2022 Technical Memorandum titled Carolina Lithium Wastewater Characterization.
2. Prior to issuing this Permit we believe it is in the best interest of all that Long Creek WWTP
submit and secure approval from the NCDEQ DWR WQPS Municipal Permitting Unit for the
anticipated increased flow to the facility. In the advent that Long Creek WWTP is unable to
accept the additional flow what alternative plan does the facility operator have to manage
and treat the proposed flow? In addition, an application from Long Creek WWTP will
include various studies and analyses to determine if the proposed receiving water can
accommodate the proposed pollutant load; including but not limited to proposed sulfate,
chloride, organic carbon content and TDS.
Two Rivers Utilities (TRU) have conducted studies and analysis of their Long Creek WWTP
current systems. PLCI and Two Rivers Utilities have exchanged letters stating that PLCI will meet
whatever limits are imposed by Two Rivers Utilities and Two Rivers Utilities has responded that
they can accept PLCI's proposed volume and load as long as limits and conditions are met which
are under development.
Please see Attachment 2 which includes PLCI's letter to Two Rivers Utilities and Two Rivers
Utilities response.
3. At this time, we believe based upon the information provided that proposed coverage under
NCG02 may be inadequate to meet the operational needs of the facility. It is our position
that the proposed industrial process waters potentially generated at this mine site would
not have coverage under this stormwater general permit including: boiler blowdown,
scrubber waste, cooling water. These wastewaters may need to be discharged under the
potential POTW Significant Industrial User Permit or seek separate coverage to discharge
through the NPDES program. Again, at this time we request that the applicant provide
information on other wastewaters generated, including full waste characterization and
Page 1 of 6

Piedmont Lithium Carolinas, Inc. I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
proposed disposal methods.
Since discharges associated with "the waste rock disposal areas will be collected in ponds
and subject to NPDES monitoring prior to discharge to receiving waters" at this time the
applicant should apply for an NPDES discharge permit with the NCDEQ DWR WQPS IPU
prior to issuance of this Permit.
On December 28, 2022, PLCI submitted two separate NPDES Individual permit applications to
cover stormwater associated with the site. One application covers the Lithium Mine/Concentrate
Operations, and the second application covers the Lithium Hydroxide Conversion Plant. Both
applications are currently under review by DWR-WQPS.
4. The information and data provided in regards to TCLP and humidity cell analyses suggests
that the facility operator should secure an individual stormwater or wastewater permit to
commence operations. Humidity cells are not necessarily the best way to simulate the
process in mine setting and the related variation. Also, it's not known whether other real
oxidation state (e.g. low DO, anoxic) would happen or not. We recommend that this option
be evaluated and determined by the applicant before proceeding further.
PLCI completed its' Leaching Environmental Assessment Framework (LEAF) testing and
evaluated the results and its correlation to humidity cell analysis. Please see Attachment 3 to
highlight the results from the above referenced testing titled LEAF and Accelerated Weathering of
Solid Materials Using a Modified Humidity Cell (ASTM D 5744-96) Collaboration Technical
Summary.
As noted in the #3 response above, PLCI submitted two separate NPDES Individual permit
applications to cover stormwater associated with the site.
5. A review of the information provided did not include "Attachment 2 Concentrate Operation
Drawings (Sheets 1-34) as noted in Appendix G — Response to DEMLR MRO Comments,
please provide these sheets.
The missing sheets as referenced can be found as Attachment 1 of this document.
NOTE: The original documents included in Attachment A have been updated and are no longer
the correct version to review. The updated drawings are now included as part of Appendix B —
Attachment 3 of the overall response to the additional information request dated January 14, 2022.
6. The information provided in Appendix I - the Technical memo on the WWTF considerations
raises a few questions that require additional clarification as follows.
• We request that the facility operator [Long Creek WWTF (NC0020184)] review the
November 5, 2021 Technical Memorandum and acknowledge in detail that the facility
not only can accept, but can adequately handle and treat the proposed flow. This detail
should be included in their letter to Piedmont Lithium.
Page 2 of 6

Piedmont Lithium Carolinas,Inc.I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
Long Creek WWTP has conducted their studies and analysis of their current systems. PLCI
and Long Creek WWTP have continued conversations and as noted in a letter from Two
Rivers Utilities dated December 2, 2021, they can accept the quantity of water PLCI proposes
to send to Long Creek WWTP. PLCI and Two Rivers Utilities have exchanged letters stating
that PLCI will meet whatever limits are imposed by Two Rivers Utilities and Two Rivers
Utilities has responded that they can accept PLCI's proposed load as long as limits are met.
Please see Attachment 2 which includes PLCI's letter to Two Rivers Utilities and Two Rivers
Utilities response.
• Based upon the information provided baring any pretreatment issues the wastewater
system may have capacity. However, information provided did not include sufficient
detail to determine if the sewer system has adequate capacity to handle the projected
flow. The WWTP acceptance letter should include language that the existing sewer
system has adequate capacity and an identified route for the flow in MGD.
Long Creek WWTP has conducted their studies and analysis of their current systems. PLCI
and Long Creek WWTP have continued conversations and as noted in a letter from Two
Rivers Utilities dated December 2, 2021, they can accept the quantity of water PLCI proposes
to send to Long Creek WWTP. PLCI and Two Rivers Utilities have exchanged letters stating
that PLCI will meet whatever limits are imposed by Two Rivers Utilities and Two Rivers
Utilities has responded that they can accept our load as long as limits are met. Gaston County
has issued a Request for Qualifications (RFQ) to identify the engineering firm that will design
and eventually construct the lines necessary to carry the wastewater from the PLCI site to the
defined sewer system.
Please see Attachment 2 which includes PLCI's letter to Two Rivers Utilities and Two Rivers
Utilities response.
• Based upon a review of the data provided there will be potential impact to the POTW
MBAS due to oxygen transfer limits, the ability of the wastewater system to separate
solids from liquids, and the potential to create overall operational issues associated
with foaming. Thus, we request additional information from the applicant detailing how
these concerns will be addressed.
As indicated in the November 2022 Technical Memorandum, the MBAS concentration in a
wastewater sample generated by simulating the Concentrator Plant process indicated a
MBAS concentration of 0.43 mg/L. Surfactants are used only at the Concentrator Plant and
not at the Conversion Plant. The peak design flow for the Concentrator Plant is 68.2 gpm and
123.7 gpm for the Conversion Plant. On this basis, the projected discharge concentration of
MBAS from the combined streams is projected to be 0.16 mg/L.
The United States Environmental Protection Agency (USEPA) secondary drinking water
standard for foaming agents is 0.5 mg/L. The North Carolina FRESH SURFACE WATER
QUALITY STANDARDS for all classes of water is 0.5 mg/L for MBAS.
Page 3 of 6

Piedmont Lithium Carolinas, Inc. i Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
Based on the above, it is expected that there is little to no risk of MBAS causing performance
issues of the treatment plant. Pretreatment limits for MBAS can be placed on the PLCI
discharge and PLCI will meet them via evaluating multiple options.
• Additional details and supporting data are requested as to how the WWTP operator will
manage the increased flow and pollutant load to ensure that biosolids utilization at the
facility will not be impacted.
Based on the studies completed by Long Creek WWTP and their corresponding letter, they will
be able to manage the increased flow and pollutant load as long as PLCI meets the limits and
conditions imposed by the future permit.
• Has the applicant evaluated how the potential levels of sulfate, chloride and TDS
concentrations can impact toxicity testing at the POTW? If so, please provide additional
details and data on how this was determined, such as a pilot study or bench scale
testing.
Since these comments were received, two Technical Memorandums were issued
characterizing the projected flows and constituent loads for the Carolina Lithium project that are
proposed to be sent to Long Creek WWTP. Please see Attachment 1 for the February 22, 2022
Technical Memorandum titled Wastewater Treatment Plant Considerations Update and the
November 9, 2022 Technical Memorandum titled Carolina Lithium Wastewater
Characterization.
• The information and analysis provided in the 12/15/21 response evaluates compliance
with applicable Water Quality Standards; however, additional detail is required to
evaluate how the facility operator will manage inhibition or sludge criteria at the plant.
Please provide additional detail specifying how the plant operator will address inhibition
or sludge criteria or an analysis of same.
Since these comments were received, two Technical Memorandums were issued
characterizing the projected flows and constituent loads for the Carolina Lithium project that
are proposed to be sent to Long Creek WWTP. Please see Attachment 1 for the February 22,
2022 Technical Memorandum titled Wastewater Treatment Plant Considerations Update and
the November 9, 2022 Technical Memorandum titled Carolina Lithium Wastewater
Characterization.
Page 4 of 6

Piedmont Lithium Carolinas, Inc. I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
7. Based upon the information provided to DWR it will be necessary to have a robust
pretreatment treatment unit at the Lithium plant and the POTW will need to develop local
limits. Please provide details so that DWR can evaluate.
Since these comments were received, two Technical Memorandums were issued characterizing
the projected flows and constituent loads for the Carolina Lithium project that are proposed to be
sent to Long Creek WWTP. Please see Attachment 1 for the February 22, 2022 Technical
Memorandum titled Wastewater Treatment Plant Considerations Update and the November 9,
2022 Technical Memorandum titled Carolina Lithium Wastewater Characterization.
Once Long Creek WWTP provides limits and conditions, PLCI's pretreatment unit will be
designed to meet such limits.
The agreement to this point can be found in Attachment 2.
8. As a final note of concern the high flow wet weather data used to make assimilative
capacity determinations is very optimistic. We request that assimilative capacity
determinations be made based upon low flow data. Please provide the updated analyses.
Since these comments were received, two Technical Memorandums were issued characterizing
the projected flows and constituent loads for the Carolina Lithium project that are proposed to be
sent to Long Creek WWTP. Please see Attachment 1 for the February 22, 2022 Technical
Memorandum titled Wastewater Treatment Plant Considerations Update and the November 9,
2022 Technical Memorandum titled Carolina Lithium Wastewater Characterization.
Page 5 of 6

Piedmont Lithium Carolinas,Inc.I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
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Page 6 of 6

Piedmont Lithium Carolinas, Inc. I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
Appendix C — Attachment 1
Technical Memorandum Wastewater Treatment Plant
Considerations Update (February 22, 2022)
Technical Memorandum Carolina Lithium — Wastewater
Characterization (November 9, 2022)

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PIEDAAONT
Technical
Memorandum
Wastewater Treatment Plant
Considerations Update
Piedmont Lithium Carolinas, Inc.
Gaston County, North Carolina
February 22, 2022

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Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Contents
Contents
Contents ......................................................................................................................................i
Introduction................................................................................................................................ 1
Projected PLCI Wastewater Characteristics............................................................................... 2
TotalWastewater Flow........................................................................................................... 2
Total Wastewater Flow and Characteristics............................................................................ 3
Potential Impact of PLCI Wastewater on WWTPs...................................................................... 5
PermittedFlows...................................................................................................................... 5
NC Water Quality Standards .................................................................................................. 5
Effluent Characteristics........................................................................................................... 6
Considerations for Long Creek WWTP................................................................................... 8
Conclusion and Recommendations............................................................................................ 9
Tables
Table 1. Projected Flows from PLCI Facilities*........................................................................... 3
Table3. Existing Plant Flows..................................................................................................... 5
Table 4. Evaluation of Impact of PLCI water on Long Creek WWTP effluent.............................. 7
i

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Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Introduction
Introduction
Piedmont Lithium Carolinas, Inc. (PLCI) is proposing to construct an open pit mine in the
Carolina Tin-Spodumene Belt (TSB) of North Carolina where lithium-bearing pegmatites have
been identified. The PLCI Carolina Lithium Project consists of the Concentrate Operations and
the Lithium Hydroxide Conversion Plant (the Site) and is located in the TSB of the Piedmont
physiographic province in south-central North Carolina. The Site is approximately 1,548 acres in
size and is in an unincorporated area of Gaston County on private land surrounding portions of
Hephzibah Church Road, Whitesides Road, and St. Mark's Church Road, approximately 1 mile
east of Cherryville, North Carolina.
The overall Concentrate Operation is composed of three components: the Piedmont Lithium
Carolinas Mine #1, a Concentrate Plant, and an Industrial Minerals Plant. The Piedmont Lithium
Carolinas Mine #1 will consist of four open pits of varying sizes, a waste rock disposal area,
topsoil stockpiles areas, haul roads, and other mine support areas. This process will produce
native overburden and dry-stacked concentrator tails at the Concentrate Plant. PLCI is proposing to
dry-stack the co-mingled mine refuse streams (native overburden and concentrator tails) in the
waste rock disposal area and/or use the refuse for reclamation to backfill the mine pits. The Lithium
Hydroxide Conversion Plant will accept concentrated ore from the Concentrate Plant and
ultimately produce Analcime tailings, which PLCI is also proposing to dry-stack and co-mingle as
mine refuse in the waste rock disposal area. Tailings from either the Concentrate Operation or
Lithium Hydroxide Conversion Plant will be mechanically dewatered and dry stacked; slurry
impoundments are not proposed. This integrated approach (Concentrate Operations and Lithium
Hydroxide Conversion Plant)will allow PLCI to concentrate and convert mined ore to battery-
grade lithium hydroxide within Gaston County, Cleveland County, and surrounding areas.
HDR Engineering Inc. of the Carolinas (HDR) has been tasked with developing an
understanding of potential receiving municipal wastewater treatment plants (WWTPs) that could
accept industrial wastewater discharged from the PLCI chemical conversion process. In order to
evaluate the potential capability of WWTPs to accept the PLCI process water discharge,
National Pollutant Discharge Elimination System (NPDES) permit discharge criteria and the size
of receiving streams were evaluated against wastewater characterization parameters developed
by HDR based on production information provided by Primero.' NPDES permit discharge
criteria are based on the North Carolina 15A NCAC 02B Water Quality Standards for Surface
Water and In-Stream Target Values for Surface Waters.2
Four options were identified for possible treatment of the PLCI discharge: the City of
Cherryville's Cherryville WWTP, the City of Gastonia's Long Creek WWTP, the City of Shelby's
First Broad River WWTP, and the City of Lincolnton's Lincolnton WWTP (Figure 1). The
Cherryville WWPT is the closest facility to the PLCI site and was initially considered as the best
option due to proximity; however as discussed herein, the three alternative plants all have larger
18605-MEM-PR-009 C, Primero,dated June 14,2021
2 https://deq.nc.gov/documents/nc-stdstable-06102019
1

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations FR
treatment facilities and larger receiving streams. In addition, the larger municipalities have active
industrial pretreatment programs.
LEGEND
Q PLCI Carolina Lithium Project
l
Wastewater Treatment Plants
0 ,-'k
Wes
1). R
Lin: d n th n C°QF
Cherryville WWTP
(City of Cherryville)
Lincolnton WWTP
L+,n]a tr �- - _ _ "'9`� (City of Lincolnton)
GASTr,,;, Wigh Shaalr.
_ Ch-rrydili- ..
K
c
V
tie Long Creek WWTP
(City of Gastonia)
t
Besse m-r m y
First Broad River WWTP
(City of Shelby) Gastonia
P.1 uiilain Etlm5n1
t•rrui-i' �
i
nl
Figure 1. Location of reviewed municipal wastewater treatment facilities
Projected PLCI Wastewater Characteristics
Total Wastewater Flow
The PLCI total facility discharge, based on updated design data provided by Primero on
February 16, 2022, is projected to be an average of 0.284 mgd or 197 gpm (Table 1), on which
calculations for Tables 2-4 are based. The peak hydraulic design loading for the conveyance
system should safely accommodate a greater flowrate than this. The majority of the flow comes
from the Lithium Hydroxide Conversion Plant. This plant chemically converts the concentrated
lithium from the ore into lithium hydroxide. A smaller stream of wastewater is also generated
from the Concentrator Plant. The Concentrator separates the lithium from the rest of the rock
present, through grinding and flotation. Sanitary wastewater is combined with process
wastewater at the site boundary for proposed disposal to a municipal WWTP. Sanitary
wastewater generation rates were calculated using NC standards for wastewater production
from manufacturing facilities with showers, at a peak manpower loading of 200 people onsite.
2

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Projected PLCI Wastewater Characteristics
Table 1. Projected Flows from PLCI Facilities*
Total Wastewater Flow Nominal Average Peak Flow
m3/hr** gpm mgd m3/hr** gpm mgd
Concentrator Wastewater 7.74 34.1 0.049 15.48 68.2 0.098
Conversion Wastewater 18.6 81.9 0.118 28.1 123.7 0.178
Sanitary Wastewater 0.9 4.0 0.006 1.2 5.3 0.008
Total 27 120 0.173 45 197 0.284
'Due to ongoing refinement in process engineering of facility,flows have changed from previous projections
**derived from Primero design data, provided February 16,2022
^calculated using NC standards for wastewater production from manufacturing
facilities with showers, increased to 40 gpd from design standard of 35 gpd for safety
Total Wastewater Flow and Characteristics
In the Concentrator plant, there are a number of operations in which ores are processed to
separate byproducts and undesirable components through gravity and flotation processes. The
water recycled in the various operations passes through a clarifier dedicated to that circuit
before reuse. Thus, all the water discharged from the concentrator plant is in essence clarified
water. The excess water discharged from the concentrator area is treated in a wastewater
treatment system consisting of the processes of lime addition for precipitation of fluoride and
metals, followed by dissolved air flotation (DAF), sand filtration and granular activated carbon
filtration. This process has been projected by Primero to remove fluoride to a concentration of
50 mg/L and TOC to a concentration of 19 mg/L. Other parameters, for which data is not yet
available, are estimated based on published solubility data and past observations of
coprecipitation of various metals with iron hydroxide precipitates. As shown in Table 2, the raw
wastewater iron concentration is 569 mg/L, so the solids produced from increasing the pH will
be over 1000 mg/L of iron hydroxide. Due to the projected low TOC concentration after
precipitation and activated carbon absorption, it is expected that there will be little remaining
MBAS, and foaming issues which previously were identified as a potential concern are no
longer expected to be an issue.
This wastewater is then blended with the discharge from the Conversion plant. The Conversion
plant (also referred to as the lithium hydroxide plant) discharge is made up of the boiler
blowdown, the ion exchange elutriant (rinsewater), and bleed streams from filter cake washing,
filter cake filtrate and the CO2 scrubber recirculating streams. These streams are not treated
other than the treatment received in recirculation. The expected individual stream
characteristics and the combination of the concentrator plant and conversion plant waters are
shown below in Table 2. Note that there are no other wastewater streams produced onsite. All
Cooling Tower and Boiler blowdown streams and solution bleed streams are included in the
calculated flows in Table 1 and the characteristics in Table 2. Table 2 also includes the sanitary
wastewater stream from all locations on the plant site, using typical sanitary wastewater
characteristics for strong sewage. As shown, the combined stream has an average flow of 27.2
cubic meters/hour, or 0.173 mgd. Peak flow is projected to be 0.284 mgd. The principal
inorganic constituents include sodium and chloride, with lesser amounts of calcium, sulfate,
phosphorus and lithium.
3

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Projected PLCI Wastewater Characteristics
Table 2:Wastewater Characteristics
Concentrator Conversion Plant Sanitary Design Average
Wastewater Wastewater Wastewater Wastewater To TRU
nominal high low end high end
WTP Calc WTP low end of highend low end end of low end of range high end of range
Name Feed Discharge range of range nom of range range design of range conc. of range conc.
Flow-Maximum-mgd 0.098 0.178 0.008 0.284
Flow Design-mgd 0.049 0.118 0.006 0.173
Units-Wastewater Parameters mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L lb/day mg/L lb/day mg/L
Total Dissolved Solids 6170 3072 1536 4609 11131.52 5566 16697 622 6057 4208 16795 11668
Fluoride 2590 50 25 75 1 10 7 31 21
Chloride 250 250 125 375 3845 1923 5768 80 1944 1351 5826 4047
PO4-P 84 17 8.5 25.5 581 290 871 15 289 201 867 602
Carbon(total) 300 300 14 10 14 10
Total Organic Carbon 190 19 1 9.5 28.5 1 250 16 11 24 16
Hardness[mg/Las CaCO3] 1610 2292 1146 3438 125 475 330 1412 981
Aluminum(total) 533 20 10 30 0.1 4.1 2.8 12.3 8.5
Arsenic(total) 0.45 0.30 0.15 0.45 0.00 0.06 0.04 0.18 0.13
Ba ri u m(tota 1) 1.83 1.83 0.92 2.75 0.01 0.37 0.26 1.12 0.78
Be ryl I i u m(tota 1) 0.322 0.100 0.050 0.150 0.001 0.020 0.014 0.061 0.043
Ca I ci u m(tota 1) 568 800 400 1200 10 1 25 50 167 116 518 360
Chromium(total) 5.71 0.10 0.05 0.15 0.01 0.021 0.015 0.062 0.043
Copper(tota 1) 1.32 0.10 0.05 0.15 0.10 0.025 0.018 0.066 0.046
Iron(total) 569 10 5 15 1 2.1 1.5 6.2 4.3
Potassium(total) 33.9 33.9 17.0 50.9 300 100 500 10 106 73 513 356
Lithium(total) 2.41 2.41 1.21 3.62 158 100 207 0.01 99 69 205 142
Magnesium(total) 54.5 54.5 27.3 81.8 10 12 8 34 24
Manganese(total) 91.1 70 35 105 0.1 14 10 43 30
Sodium(total) 461 461 231 692 5988 2994 7385 80 3041 2112 7545 5242
Lead(total) 1.90 0.20 0.10 0.30 0.01 0.04 0.03 0.12 0.09
Anti mony(tota 1) 0.082 0.025 0.013 0.038 0.001 0.005 0.004 0.015 0.011
Selenium(total) 0.0011 0.0011 0.0006 0.0017 0.0030 0.0004 0.0003 0.0008 0.0006
Silicon(total) 392 100 50 150 5 21 14 62 43
Sulfate# 1200 1200 600 1800 250 100 400 70 347 241 1133 787
Thallium(total) 0.0111 0.0020 0.0010 0.0030 0.0010 0.0005 0.0003 0.0013 0.0009
Zinc(total) 7.87 1.00 0.50 1.50 1 0.10 0.21 0.15 0.62 0.43
The projections on water quality are based on chemical consumption and mass balance
calculations, and information supplied by process technology and equipment suppliers. Using
this information and past experience with treatment of these streams, projected effluent quality
from the concentrator treatment system was developed. Laboratory process simulations are in
progress to better define the wastewater characteristics for the Concentrator wastewater after
treatment and will provide a clearer definition of water quality and blowdown flows. Similarly, for
the Converter (lithium hydroxide) plant, process design is still in progress, and some refinement
of the characteristics of water from that system is expected. Conservative estimates have been
used, so that as more information becomes available, it is expected that the projected discharge
water quality will fall within the projected range.
4

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Potential Impact of PLCI Wastewater on WWTPs
Potential Impact of PLCI Wastewater on WWTPs
Permitted Flows
Table 3, below, shows the current and permitted flows to each of the wastewater treatment
plants considered, along with the estimated low flow in the receiving stream. Of the WWTPs
considered, the Long Creek WWTP has the highest permitted flow capacity, approximately 10
million gallons per day (mgd) more than the next highest flow capacity. Table 2 (below) ranks
the WWTPs in order of highest permitted flow capacity to least. The higher the flow capacity, the
more advantage a WWTP would have for dilution of the influent wastewater.
Table 2 also summarizes the receiving stream minimum flowrates used for NPDES permit limits.
The Long Creek and First Broad River WWTPs have substantially more dilution capability as
their receiving stream flow is larger and would dilute the WWTP effluent to a greater degree,
potentially allowing higher concentrations for some parameters in the effluent discharges (like
sulfate and chloride). Allowable parameter effluent levels are determined by the state modelling
the receiving streams' mixing zone, to ensure enough dilution of a certain discharge parameter
can occur relative to NC stream standards within a short distance of the discharge point.
Table 2. Existing Plant Flows
Flow(mgd) Instream Low Flow*
Rank Facility Current Current Average+ Current Concen-Waste Receiving Stream
Permit Average PLCI Peak Maximum (cfs) (mgd)
tration*
South Fork Catawba River
1 Long Creek WWTP 16 6.2 6.484 27.2 8% 130 84
-Class WS-V
First Broad River
2 First Broad River WWTP 6 3.24 3.524 11.8 10% 55 36
-Class C
South Fork Catawba River
3 Lincolnton WWTP 3.5 1.96 2.244 12.75 4.16% 83 54
-Class WS-IV
Indian Creek
4 Chenyville WWTP 2 0.65 0.934 1.5 16% 9 5.8
-Class C
*Current average plus PLCI Peak flow divided by Receiving Stream low flow
Evaluation of the Cherryville WWTP indicates that the maximum flow from PLCI would make up
about 40% of the average flow to the treatment plant. Given the projected concentration of
chlorides and sulfates in the PLCI discharge, Cherryville could not meet the receiving stream
water quality criteria for these parameters if the PLCI discharge is directed there. The dilution
available in Indian Creek is limited and requires that the Cherryville WWTP discharge be close
to the stream water quality standards. Therefore, the Cherryville WWTP is removed from
consideration.
Based on dilution potential under low flow conditions of receiving streams, particularly for
chlorides in this case, it is highly desirable to convey the PLCI wastewater effluent to the Long
Creek WWTP and undesirable to convey the PLCI water to the Cherryville WWTP.
NC Water Quality Standards
All surface waters in North Carolina are assigned a primary classification by the NC Division of
Water Resources (DWR). All waters must at least meet the standards for Class C (fishable and
5

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Potential Impact of PLCI Wastewater on WWTPs
swimmable)waters. The other primary classifications provide additional levels of protection for
primary water contact recreation (Class B) and drinking water (Water Supply [WS] Classes I
through V). The state of North Carolina has established water quality standards for surface
waters and in-stream target value standards.3 These stream standards define the required
quality in the stream, and a WWTP's receiving stream must meet them for its assigned surface
water classification, as approved in a WWTP effluent NPDES permit limits.
• Class C Waters— is the base waters classification for basic protection of aquatic life and
secondary recreation (i.e. fishable and swimmable waters); all waters must at least meet
the standards for Class C Waters;
• Class WS-IV Waters—water supply waters used as sources for drinking, culinary, or
food processing purposes where a WS-1, 11 or III classification is not feasible; usually in
moderately to highly developed watersheds;
• Class WS-V Waters —water supply waters which are generally upstream and draining to
Class WS-IV waters or waters used by industry to supply their employees with drinking
water or as waters formerly used as water.
The criteria of concern for receiving streams classified as Class WS I-V receiving the PLCI
discharge would include Chloride (230 mg/L), Sulfate (250 mg/L), Methylene Blue Active
Substances (MBAS) (0.5 mg/L), Arsenic (10 pg/L), Benzene (1.10 pg/L), and polynuclear
aromatic hydrocarbons (PAHs) (2.8 qg/L). In comparison, Class C receiving waters have
required water quality for the following criteria: Arsenic (150 pg/L) and Chloride (230 mg/L).
Class C waters are more heavily monitored for metals.
The MBAS test measures the presence of anionic surfactants or detergents to monitor the
potential for foaming. In the biological process employed at all four of the plants noted above,
foaming in the biological system could:
(1) be damaging to the treatment process, as foam formation would limit oxygen transfer;
(2) limit the WWTP's ability to separate solids from liquid by stabilizing small particles; and,
(3) present operational issues that could result in the WWTP not accepting the influent.
The concern is that frothing agents used in flotation would continue to froth once they reach the
WWTP. While it is possible that any of these WWTPs could require a stipulation in a
pretreatment permit about frothing characteristics, the effluent from the concentrator plant
treatment system after passing through solids precipitation and activated carbon would not be
expected to contain a substantial concentration of MBAS that would cause foaming to occur.
Effluent Characteristics
An evaluation was made of the potential impact of the PLCI wastewater on the effluent from the
Long Creek treatment plant (Table 3). Table 4 shows characteristics based on the low value and
high value of the expected range of possible parameter concentrations. Whereas Table 2 is
based on the design values, Table 4 shows a low end of the range that is generally about 50%
3 https://deq.nc.gov/about/divisions/water-resources/planning/classification-standards/surface-water-standards
6

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Potential Impact of PLCI Wastewater on WWTPs
less than the nominal value, and a high end that is in most cases 50% above the nominal value.
This range reflects (1) the level of accuracy of the design values at this stage of development,
and (2) some conservatism in the water quality characteristics to provide a factor of safety. The
high flow capacity at the Long Creek WWTP provides substantial dilution, and the receiving
stream also provides more dilution than the First Broad River and Lincolnton WWTPs. For the
Long Creek WWTP, the projected effluent sulfate, chloride and TDS concentrations are
sufficiently low and would meet stream standards in the effluent before considering dilution in
the receiving stream. Other parameter concentrations are within or reasonably close to stream
standard values. Thus, the best fit for the PLCI wastewater is the Long Creek WWTP.
Table 3. Evaluation of Impact of PLCI water on Long Creek WWTP effluent
Stream
Parameter Units Standards ong Creek
PLCI low PLCI high Long Creek Long Creek
existing end of end of +low end +high end Discharge
effluent range range PLCI PLCI Limits
Flow m d 6.2 0.173 0.284 6.373 6.48 16
BOD5 mg/L 3 2 20 3 3.0 5/10
Ammonia N mg/L 0.20 0.10 5.00 0.20 0.25 2/4
Total N m /L 21.1 0.2 10.00 21 22
Sulfate mg/L 250 66 241 787 71 98
Chloride mg/L 250 56 1351 4047 91 231
TDS m /L 1000 223 4205 11668 331 724
PO4-P 2 199 602 7.3 28
Sodium 45 2112 5242 102 273
Calcium 25 116 360 27.7 39.9
Fluoride m /L 1.8 1.0 7.1 21.3 1.2 1.9
Lithium mg/L 0.20 68.62 142.4 2.1 6.4
Arsenic m /L 0.01 0.005 0.043 0.128 0.006 0.010
Benzene* mg/L 0.0011 <0.001 <0.001 <0.001 <0.001 <0.001
PAH m /L 0.0000028 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Aluminum mg/L 0.010 2.8 8.5 0.09 0.38
Iron m /L 0.1 1.5 4.3 0.14 0.28
blue is after treatment in Long Creek Treatment Plant
red is assumed values based on typical wastewater characteristics
The First Broad River WWTP would be a second choice and is also the furthest from the Site.
Combined with PLCI effluent, the First Broad River WWTP TDS concentration would be two
times the predicted level in the Long Creek WWTP. However, since the First Broad River is
Class C, there is no stream standard for TDS. In communication with the City of Shelby, staff
indicated that the nearest connection point in Shelby's collection system would need to be
upgraded to accept the flow from PLCI.
Finally, the Lincolnton WWTP may not be a desirable choice, because the smaller WWTP with
the PLCI effluent would have the highest concentrations of sulfate, chloride and TDS. Also, the
7

Piedmont Lithium Carolians,Inc. i Wastewater Treatment Plant Considerations ���
Potential Impact of PLCI Wastewater on WWTPs
Lincolnton WWTP was originally a 6 mgd facility that was downgraded by the NC Department of
Environmental Quality to 3.5 mgd. This downgrade was due to condition of assets within the
WWTP and could indicate a potential infrastructure issue.
Considerations for Long Creek WWTP
The Long Creek WWTP appears to be the best option for the PLCI wastewater; however, based
on the information supplied by the facility process engineer, the following parameters still need
to be considered and may become discussion points for a pre-treatment permit: Phosphorus,
Benzene, PAHs, Fluoride, Lithium, and MBAS. In addition, Gastonia will also evaluate any
impacts on biosolids utilization under pretreatment regulations.
Phosphorus (particularly phosphate) is a nutrient that is frequently the controlling factor in
biological growth and is commonly controlled to prevent undesirable levels of biological activity
in streams. Evaluations are currently in progress to make changes to the production process to
eliminate most of the phosphorus present.
Benzene is a component of kerosene, which is used in limited amounts at the Concentrator
plant. It is largely biodegradable and should be effectively removed in the WWTP biological
treatment process; however, the current characterization does not yet include data for benzene.
Benzene is also effectively removed by activated carbon and would not be expected to be
present in the effluent from the Concentrator Treatment System. Polynuclear Aromatic
Hydrocarbons (PAHs) can also be present in kerosene and are not generally well biodegraded.
However, PAHs are also effectively removed by activated carbon, and should thus be limited in
the discharge from the facility, if further characterization work indicates that PAH concentrations
in the wastewater are problematic, pretreatment for PAH removal may be required.
It is not expected that either Fluoride or Lithium would negatively impact the South Fork
Catawba River at the concentrations shown in Table 4.
MBAS is a concern because the frothing agents used in flotation would continue to froth once
they reach the WWTP, so the potential exists for a foaming issue. However, MBAS (being
organic compounds) also have a tendency to be absorbed onto activated carbon and should
thus be very limited in the Concentrator Treatment System.
Additionally, the anticipated increase in sulfate, chloride and TDS concentrations could have an
impact on the Long Creek WWTP's effluent toxicity testing. However, only bench scale testwork
or actual testing would accurately determine this. Bench scale testing could be conducted on a
mixture of actual municipal wastewater from the Long Creek WWTP and a synthetic solution of
PLCI wastewater once the PLCI stream is better characterized. It would be ideal for the mixture
to be subject to the same treatment processes employed at the Long Creek WWTP, which may
be difficult. A literature-based evaluation of potential toxicity issues for a municipal wastewater
and PLCI wastewater mixture is likely effective in lieu of actual treatment per Long Creek
WWTP processes.
It is recommended to pursue connection to Gastonia based on:
8

Piedmont Lithium Carolians,Inc. I Wastewater Treatment Plant Considerations ���
Conclusion and Recommendations
• The Long Creek WWTP has a pretreatment program;
• the capacity at Gastonia's Long Creek WWTP is best able to accept the waste stream of
the WWTPs evaluated; and
• the receiving stream (South Fork Catawba River) has the largest flow of all receiving
streams associated with the evaluated WWTPs.
There are two potential connection points to Gastonia's collection system for initial consideration
— one at the Apple Creek Business Industrial Park and one at the High Shoals Lift Station near
Gaston County Landfill (upstream of the Long Creek WWTP). The next steps would be to
continue discussions with Gastonia on connection points, determine alternatives for the
infrastructure needed to convey the waste to the connection point, and then implementation
(design, permitting, construction).
Conclusion and Recommendations
In conclusion, the best WWTP option to discharge PLCI's wastewater would ultimately be to the
Long Creek WWTP. Not only is the WWTP facility equipped to handle the volume and
characteristics of the PLCI wastewater, but the receiving stream also has a flow capacity that
will further dilute the wastewater to desirable stream standards.
A full wastewater characterization has been requested from the facility engineers and will be
done as part of process development work currently in progress. Gaps in PLCI effluent data
come largely from activated carbon removal efficiencies for MBAS and organic alcohols, as well
as inorganic parameters whose concentration will be controlled by coprecipitation in the fluoride
precipitation step of the Concentrator treatment plant.
In lieu of a full wastewater characterization, a literature-based review of the impact of the
various components of the PLCI water on the treatment process, residual solids characteristics
and potential toxicity impacts could be conducted.
9

440 S Church Street, Suite 1200
Charlotte, NC 28202
704-338-6710
hdrinc.com
© 2022 HDR, Inc., all rights reserved

PIEDAAONT
Technical
Memorandum
Carolina Lithium - Wastewater
Characterization
Piedmont Lithium Carolinas, Inc.
Gaston County, North Carolina
November 9, 2022

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Piedmont Lithium Carolians, Inc. I Wastewater Characterization ���
Contents
Contents
Contents ......................................................................................................................................i
Introduction................................................................................................................................ 1
TotalWastewater Flow............................................................................................................... 1
Wastewater Stream Characteristics ........................................................................................... 2
Concentrator Plant Wastewater Characteristics...................................................................... 2
Conversion Plant Wastewater Characteristics........................................................................ 3
Mixed Wastewater Characteristics.......................................................................................... 4
Precipitates......................................................................................................................... 5
Metalloids............................................................................................................................ 6
OtherImpacts ..................................................................................................................... 6
Summary ................................................................................................................................... 7
Tables
Table 1. Projected Flows from Carolina Lithium Project Facilities .............................................. 2
Table 2. Concentrator Plant Wastewater Sample....................................................................... 3
Table 3. Conversion Plant Wastewater Sample ......................................................................... 4
Table 4. Combined Wastewater Characteristics......................................................................... 5
i

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i

Piedmont Lithium Carolians,Inc. I Wastewater Characterization ���
Introduction
Introduction
Piedmont Lithium Carolinas, Inc. (Piedmont) is proposing to construct an open pit mine in the
Carolina Tin-Spodumene Belt (TSB) of North Carolina where lithium-bearing pegmatites have
been identified. The Carolina Lithium Project (the Site) consists of the Concentrate Operations
(Concentrator Plant) and the Lithium Hydroxide Conversion Plant (Conversion Plant) and is
located in the TSB of the Piedmont physiographic province in south-central North Carolina (NC).
The Site is approximately 1,548 acres in size and is in an unincorporated area of Gaston County
on private land surrounding portions of Hephzibah Church Road, Whitesides Road, and St.
Mark's Church Road, approximately 1 mile east of Cherryville, North Carolina.
The production of lithium from the lithium-bearing pegmatites called spodumene, requires
production of a spodumene concentrate and conversion to lithium hydroxide. In the Concentrate
Operations process, grinding and flotation are used to separate the undesirable components
from spodumene, resulting in an increased concentration of lithium in the spodumene
concentrate product. Some of these processes are wet and involve the use of chemical
reagents to enhance separation. The spodumene concentrate is then taken to the Conversion
Plant, where it is then chemically converted to lithium hydroxide. Both of these operations use
water and generate wastewater streams that would require treatment prior to discharge. This
integrated approach (Concentrate Operations and Lithium Hydroxide Conversion Plant) will
allow Piedmont to concentrate and convert mined lithium-bearing spodumene to battery-grade
lithium hydroxide.
Piedmont intends to pretreat the collected onsite process wastewater to discharge to Two
Rivers Utilities (TRU) for treatment at their Long Creek Wastewater Treatment Plant (WWTP).
In order to evaluate the potential quality of generated wastewater, Piedmont in conjunction with
Primero and Metso-Outotec, simulated the concentration and conversion processes in a
laboratory, utilizing ore samples extracted from the site. The laboratory simulation employed the
proposed processes that will be used to produce the spodumene concentrate which is then
used to produce battery-grade lithium hydroxide as the final product. The laboratory simulation
was conducted by North Carolina State University for the concentrator process and by Metso-
Outotec for the conversion process. HDR Engineering Inc. of the Carolinas (HDR) was tasked
with ordering the laboratory analysis and analyzing the characterization results of the two
separate wastewater streams from each of the Concentrate and Conversion Plants. To
characterize and analyze the combined discharge as one wastewater stream, HDR simulated
the combined discharge mixture using OLI Flowsheet (version 10.2), which is a software used to
model process chemistry in chemical process and treatment systems. This technical memo
outlines and identifies the wastewater characteristics of the separate wastewater streams as
well as the combined mixture.
Total Wastewater Flow
The Carolina Lithium Project total facility discharge is expected to consist of combined
wastewater from the Concentrator Plant, the Conversion Plant, and sanitary wastewater
1

Piedmont Lithium Carolians,Inc. I Wastewater Characterization ���
Wastewater Stream Characteristics
generated onsite. The Concentrate and Conversion Plant wastewaters will be pretreated as
needed to comply with TRU provided requirements, while the sanitary wastewater will be
conveyed along with the pretreated wastewater to the Long Creek WWTP.
The projected flowrates from the Carolina Lithium Project facilities are summarized in Table 1.
The peak hydraulic design loading for the conveyance system should safely accommodate a
greater flowrate than the indicated peak. The majority of flow comes from the Lithium Hydroxide
Conversion Plant. This plant chemically converts the lithium-bearing spodumene concentrate to
lithium hydroxide. A smaller wastewater flow is generated from the Concentrator Plant. Sanitary
wastewater is combined with process wastewater at the site boundary for proposed disposal to
the Long Creek WWTP. Sanitary wastewater generation rates were calculated using NC
standards for wastewater production from manufacturing facilities with showers, at a peak
manpower loading of 200 people onsite.
Table 1. Projected Flows from Carolina Lithium Project Facilities
Total Wastewater Flow Nominal Average Peak Flow
m3/hr* gpm mgd m3/hr* gpm mgd
Concentrator Wastewater 7.74 34.1 0.049 15.48 68.2 0.098
Conversion Wastewater 18.6 81.9 0.118 28.1 123.7 0.178
Sanitary Wastewater** 0.9 4.0 0.006 1.2 5.3 0.008
Total 27 120 0.173 1 45 197 0.284
"derived from Primero design data, provided February 16,2022
calculated using NC standards for wastewater production from manufacturing facilities with showers,increased to 40
gpd from design standard of 35 gpd for safety
Wastewater Stream Characteristics
Concentrator Plant Wastewater Characteristics
The primary process of the Concentrator Plant is to separate lithium-bearing spodumene from
the byproducts and undesirable components through gravity and flotation processes. Water
used in this facility is recycled extensively. A laboratory simulation of the Concentrate
Operations produced a sample of wastewater, representative of the blowdown stream from the
Concentrator Plant without pretreatment, which was then analyzed by Pace Laboratories, a
certified North Carolina laboratory. The analytical results from this sample are summarized in
Table 2.
There was a limited sample amount generated from the Concentrate Operations simulation; as
such, the analytical identification is limited to parameters which were suspected to be present by
virtue of their use in production operations or in the raw material. Notable results from this
analysis include a pH of 2.0, aluminum concentration of 363 mg/L, fluoride concentration of 272
mg/L, and silicon concentration of 656 mg/L.
2

Piedmont Lithium Carolians,Inc. I Wastewater Characterization ���
Wastewater Stream Characteristics
Table 2. Concentrator Plant Wastewater Sample
Parameter Units Result
Iron mg/L 78.6
Manganese mg/L 11.9
Potassium mg/L I 38.3
Sodium mg/L 518
Calcium mg/L 141
Magnesium mg/L 24.9
Silicon mg/L 656
Aluminum mg/L 363
Beryllium mg/L 0.097
Chromium mg/L 1.41
Copper mg/L 0.060
Lead mg/L 0.198
Molybdenum mg/L 0.121
Nickel mg/L 0.925
Zinc mg/L 1.79
Lithium mg/L 2.25
Total Dissolved Solids (TDS) mg/L 4700
pH Std 2.0
Total Kjeldahl N mg/L 11.2
Fluoride mg/L 272
Phosphorus mg/L 9.3
Chemical Oxygen Demand mg/L 4050
Total Organic Carbon (TOC) mg/L 222
Conversion Plant Wastewater Characteristics
The Conversion Plant (also referred to as the Lithium Hydroxide Conversion Plant) discharge is
comprised of the boiler blowdown, the ion exchange elutriant (rinsewater), and bleed streams
from filter cake washing, filter cake filtrate and the CO2 scrubber recirculating streams. The
sample generated in the laboratory simulation is representative of the sum of these streams,
without pretreatment. The analysis of sample that simulates the production of this wastewater
stream is shown below in Table 3, which was also analyzed by Pace Laboratories, a certified
North Carolina laboratory. Notable characteristics of the simulated Conversion Plant wastewater
include substantial concentrations of sodium, chloride and phosphorus.
3

Piedmont Lithium Carolians, Inc. I Wastewater Characterization
Wastewater Stream Characteristics
Table 3. Conversion Plant Wastewater Sample
Parameter Units Result
Potassium mg/L 272
Arsenic mg/L 0.239
Aluminum mg/L 1.25
Antimony mg/L 0.105
Selenium mg/L 0.328
Sodium mg/L 11,400
Silicon mg/L 98
Lithium mg/L 137
pH Std units 10.3
Chloride mg/L 3560
Phosphorus mg/L 1250
COD mg/L 164
TKN mg/L 0.76
Note that there are no other process wastewater streams produced onsite. Cooling tower and
boiler blowdown streams and solution bleed streams are included in the projected flows in Table
1 and the characteristics in Table 2 and Table 3.
Mixed Wastewater Characteristics
In order to evaluate the chemistry of the combined wastewaters from both the Concentrator and
Conversion Plants, a model was prepared in the OLI Flowsheet (version 10.2) software.
Graphically the model is as shown below.
10.
Concentrator
Mixed 10
Wastewater
Conversion
Plant Mix-1
The software models the chemistry of the two wastewater streams, and identifies the
precipitation of solids, mixture pH, and overall combined wastewater characteristics. For this
model, average flowrates were used and the inputs were the two sets of characteristics
presented in Table 2 and Table 3. The output for this model given the inputs in Table 2 and
Table 3, is shown in Table 4. The columns marked liquid indicate soluble components of the
wastewater. The columns labelled as solids are precipitated and are present in the liquid as
suspended or colloidal solids. Sanitary wastewater was not included in this model, as the flow is
low and the presence of the contaminants from production operations is minimal.
4

Piedmont Lithium Carolians,Inc. I Wastewater Characterization ���
Wastewater Stream Characteristics
Table 4. Combined Wastewater Characteristics
Concentrator Plant Conversion Plant Combined Wastewater
Parameter Liquid Solids Total Liquid Solids Total Liquid Solids Total
mg/L mg/L Ib/hr mg/L mg/L Ib/hr mg/L mg/L Ib/hr
Si(+4) 53 600 11.2 97 4 52 190 15.1
Na(+1) 515 0 9.0 11277 449 7999 458
CI(-1) 0 0 0.0 3533 141 2449 140
K(+1) 38 0 0.7 269 10.7 199 11.4
AI(+3) 361 0 6.3 0.49 0.76 0.050 10.4 101 6.4
F(A) 271 0 4.7 79 4.0 4.7
Ca(+2) 141 0 2.4 0.2 42.7 2.4
Fe(+3) 62 16.2 1.4 0.000007 23.8 1.36
Mg(+2) 24.8 0 0.43 7.6 0.43
Mn(+2) 11.9 0 0.21 3.10 0.54 0.21
P(+5) 0.220 9.0 0.13 1236 49.3 829 33.2 49.4
Li(+1) 2.2 0 0.039 136 5.41 95 5.4
Zn(+2) 1.8 0 0.032 0.2880 0.266 0.0318
Cr(+3) 1.4 0 0.024 0.0010 0.423 0.0243
Ni(+2) 0.93 0 0.016 0.2830 0.000 0.0162
Pb(+2) 0.19 0 0.0034 0.0047 0.054 0.0034
Cu(+1) 2.23E-06 0.070 0.0012 1.0E-07 0.021 0.0012
Mo(+6) 0.121 0.000 0.0021 0.0310 0.006 0.0021
Be(+2) 0.093 0.000 0.0016 0.0282 0 0.0016
As 0.24 0.010 0.17 0.01
Sb 0.11 0.004 0.07 0.00
Se 0.33 0.013 0.23 0.01
TOC 222 3.8 0.00 65.5 3.80
COD 4040 69.1 164 6.7 1307 75.79
TKN 11.2 0.2 0.76 0.031 3.84 0.22
Flow, gpm 34.2 81.8 116
pH, std 2 10.3 6.3
units
Review of Table 4 leads to several observations related to the characteristics of the modeled
combined wastewater.
Precipitates
• First, when mixed in the proportions generated, the two wastewater streams function to
neutralize each other, with a resulting pH of 6.3.
• Precipitates are formed in the mixture as might be expected at a near-neutral pH. The
largest concentration comes from silicon in the Concentrator Plant wastewater. At
ambient conditions, silica (Si02) is only soluble to about 100 to 150 mg/L; silica solubility
increases substantially at an approximate pH of 9 or higher. Since the silica was present
mostly in the Concentrator Plant wastewater at acidic pH levels, even though the silica
5

Piedmont Lithium Carolians,Inc. i Wastewater Characterization ���
Wastewater Stream Characteristics
was input as soluble silica, the model correctly identified that if it was soluble as an input,
it quickly precipitated. It is likely that most of the silica is present as fine or colloidal sand.
• Aluminum is the next highest concentration of precipitate in the combined wastewater.
The minimum solubility of aluminum hydroxide occurs at a pH of 6 to 6.5. The model
indicates that the mixture will have approximately 10 mg/L soluble aluminum and about
100 mg/L aluminum present as aluminum hydroxide and possibly other precipitates.
Aluminum hydroxide is soluble to only tenths of a mg/L at this pH. The model indicates
that AIF3 and AIFa' are both present in solution in the range of 15 to 20 mg/L as soluble
complexes and thus maintains the aluminum in solution. As the combined wastewater is
diluted in domestic wastewater, the dilution of these complexes will allow for precipitation
of aluminum hydroxide to produce low soluble aluminum concentrations.
• Nearly all of the calcium and iron in the combined wastewater are precipitated. The OLI
model indicates these are in the form Ca5(PO4)3F and FeP042H2O. Concentrations of
under 1 mg/L are precipitated of manganese, zinc, chromium, lead, copper and
molybdenum, as phosphates, oxides and hydroxides.
Metalloids
• In Table 4, below the metals analyses are a block of metalloids and conventional
parameters. The OLI model requires speciation data to accurately predict the reactions
involving metalloids, which was not available due to limitations in the volume of sample
generated. These parameters and the conventional parameters are included purely on
the basis of mass balance with no accounting for reactions that might capture them as
solids. It is likely that some of the arsenic and antimony will co-precipitate with iron and
aluminum precipitates. The degree of removal of arsenic, antimony, iron, and aluminum,
and the removal of any selenium by coprecipitation, is a function of pH and redox-driven
speciation of the metalloid. The concentrations shown as soluble in the combined
wastewater are thus the worst-case modeled condition.
Other Impacts
• Removal of the precipitated solids by clarification or filtration would result in the removal
of most of the precipitates in the combined wastewater.
• For conventional parameters, the Concentrator Plant wastewater COD is an order of
magnitude higher than the associated TOC. This may be due to the demand for oxygen
from the metals being oxidized in the COD test. It would normally be expected that in the
absence of large concentrations of ammonia nitrogen (a component of TKN which are all
relatively low) that oxygen demand would be on the order of 2.7 times the organic
carbon. It is believed on this basis that the TOC values offer a better representation of
the organic loading coming to the treatment facility. As noted, TKN concentrations are
projected to be below 10 mg/L.
• Of the soluble components identified in the analysis of the laboratory simulated
wastewater samples, the largest soluble components in the combined wastewater
include sodium, chloride, and phosphorus. The lithium concentration in the combined
wastewater is 95 mg/L, and the soluble fluoride is 79 mg/L.
6

Piedmont Lithium Carolians,Inc. I Wastewater Characterization ���
Summary
• For the Concentrator Plant wastewater, methylene blue active substance (MBAS) was
found to be 0.43 mg/L. TDS was found to be 4700 mg/L. Ammonia was identified at 0.49
mg/L and nitrate/nitrite nitrogen was 0.1 mg/L. Barium was 0.82 mg/L. Thallium was
below the reporting limit. Acetone was reported as 0.06 mg/L.
• For the Conversion Plant wastewater, MBAS was not run (no surfactants are used
there). Total nitrogen was 0.95 mg/L. Traces of chromium and cadmium were present
(below 0.1 mg/L), and aniline was identified as below detection limits.
Summary
Piedmont intends to pretreat the collected onsite process wastewater to the degree necessary
to discharge to the TRU Long Creek WWTP. It is Piedmont's understanding that TRU is
currently evaluating the capability of the Long Creek WWPT to accept wastewater components
such as the ones discussed herein. The modeling of the combined wastewater discharge to
include both the Concentrator and Conversion Plant wastewaters does not include onsite
pretreatment at this time; however, pending the provision of parameters and criteria from TRU,
Piedmont would tailor a pretreatment design to accommodate TRU's requirements.
7

440 S Church Street, Suite 1200
Charlotte, NC 28202
704-338-6710
hdrinc.com
© 2022 HDR, Inc., all rights reserved

Piedmont Lithium Carolinas,Inc.I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
Appendix C — Attachment 2
PLCI Letter to Two Rivers Utilities (April 11 , 2023)
Two Rivers Utilities Response (April 26, 2023)

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P I E N T
LITHIUM
April 11, 2023
Via Electronic Mail
Ms. Stephanie Scheringer
Division Manager Wastewater Treatment
Two Rivers Utilities
1300 N. Broad St
Gastonia, NC 28054
Re: Piedmont Lithium Inc. Significant Industrial User Permit
Dear Ms. Scheringer,
Piedmont Lithium Inc. ("Piedmont") and Two Rivers Utilities ("Two Rivers") continue to
engage in discussions related to Two Rivers issuing Piedmont a Significant Industrial User
("SIU") permit for process wastewater discharged from Piedmont's Carolina Lithium project in
Gaston County, North Carolina.
Piedmont and Two Rivers agree and acknowledge that their discussions regarding the
Carolina Lithium project are part of Piedmont's broad effort to obtain permits and approvals from
other State and local agencies related to the Carolina Lithium project.
In an effort to facilitate the above, Piedmont shall meet all SIU permit limits and conditions
in compliance with all applicable laws and regulations required by Two Rivers as such limits and
conditions relate to Piedmont's sanitary sewer discharge from the Carolina Lithium project.
If there are any questions concerning this matter, please contact me at [phone]
or mparker piedmontlithium.com.
Thank you,
J. Monique Parker, CSP
SVP — Safety, Environment & Health
Piedmont Lithium Inc.
• .. • Australia Address OX- 4 nfo@piedrnontlithiumcom
PIEDMONT

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TWO VERS
U T I L I T I E S
We are TRU to our customers!
April 26, 2023
Via Electronic Mail
Ms. Monique Parker, CSP
Senior Vice President for Safety, Environment and Health
Piedmont Lithium Inc.
42 E. Catawba St.
Belmont, NC 28012
RE: Acceptance of Wastewater Discharge
Dear Ms. Parker:
Two Rivers Utilities (TRU) has received Piedmont Lithium's (Piedmont) April 11, 2023 letter regarding wastewater
from the planned Carolina Lithium mining and processing operation in Gaston County. It is acknowledged that
Piedmont and TRU continue to discuss the makeup of the sanitary sewer discharge and the future Significant
Industrial User(SIU) permit that is required for the sanitary sewer discharge from the Carolina Lithium project.
Two Rivers Utilities has the available capacity at the Long Creek Wastewater Treatment Plant to treat the
proposed volume of wastewater from this project, which is a peak flow of 0.284 MGD for combined domestic
and process discharge. Per Piedmont's April 11, 2023 letter stating that all SIU permit limits and conditions, as
well as all applicable laws and regulations related to Piedmont's sanitary sewer discharge will be met, TRU can
accept and effectively treat the wastewater from the Carolina Lithium project.
TRU will continue to work with Piedmont to best determine appropriate limits and conditions for this discharge
before construction is completed. However, limits or conditions in Piedmont Lithium's SIU permit may be
revised in accordance with the City of Gastonia Code of Ordinances Section 14-289 due to unforeseen or
undisclosed pollutants (including, but not limited to the PFAS/PFOA family of compounds), municipal treatment
process interference, changing regulations or other conditions. In accordance with Gastonia's Code of
Ordinances Section 14-396, 397 and 399, Piedmont will be obligated to meet any change in requirements.
Two Rivers Utilities appreciates the information that has been provided thus far and looks forward to continuing
to work with Piedmont Lithium through the remainder of the SIU permitting process.
Sincerely,
Stephanie Scheringer
Division Manager Wastewater Treatment
Two Rivers Utilities
CC: Joe Albright, Director Public Utilities,TRU
Brian Potocki,Assistant Director Public Utilities,TRU
David Shellenbarger,Assistant WWT Division Manager Compliance,TRU
L.Ashley Smith,City Attorney, Gastonia
Keyes McGee, Pretreatment Coordinator, NCDEQ DWR

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Piedmont Lithium Carolinas, Inc. I Response to DEMLR Additional Information Request
Comments on Carolina Lithium Project by DWR-WQPS January 14,2022
Appendix C — Attachment 3
LEAF and Accelerated Weathering of Solid Materials Using a
Modified Humidity Cell (ASTM D 5744-96) Collaboration
Technical Summary

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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
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
►► ►► Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Summary
Apri12023
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)
and Accelerated Weathering of Solid Materials
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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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Leaching Environmental Assessment Framework(LEAF)
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
►►' ►► Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Summary
Apri12023
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)
and Accelerated Weathering of Solid Materials
►►' ►► Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Summary
April2023
(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)
and Accelerated Weathering of Solid Materials
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April2023
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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Leaching Environmental Assessment Framework(LEAF)
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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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