2024.02.15_ADI #4_Binder 2 of 2

Piedmont Lithium Carolina, Inc.
PIEDMONT 42 E Catawba St.
LITHIUM Belmont, NC 28012
March 15, 2024
Mr. Adam Parr, PE
NC Department of Environmental Quality
Division of Energy, Mineral, and Land Resources
1612 Mail Service Center
Raleigh, NC 27699-1612
Subject: Piedmont Lithium Carolinas, Inc.
Carolina Lithium Project
Response to Additional Information Request#4 (dated February 9, 2024)
(Binder 2 of 2)
Dear Mr. Parr:
Piedmont Lithium Carolinas, Inc. (PLCI) submitted a North Carolina Mine Permit Application on August 30,
2021 to the Division of Energy, Mineral, and Land Resources (DEMLR). DEMLR issued an Additional
Information request on October 29, 2021 (ADI#1) and PLCI responded to ADI#1 on December 15, 2021.
DEMLR issued an ADI#2 on January 14, 2022 and PLCI responded to ADI#2 on June 20, 2022 followed
by an extended response to ADI#2 on April 27, 2023. DEMLR issued ADI#3 on May 30, 2023 and PLCI
responded to ADI#3 on January 18, 2024.
DEMLR issued ADI#4 on February 9, 2024. PLCI is thankful to DEMLR and other agencies for their
continued diligence and review of material.
Please see the following responses to the items from ADI#4. The agency comments are in bold text and
responses are provided in regular text. Two copies of this response are provided, including an electronic
version.
Should you have any questions or require additional information following your review of the enclosed
materials, please contact me, Monique Parker, at(704) 813-2301 or mparker(a)piedmontlithium.com.
Yours truly,
J. Monique Parker, CSP
Senior Vice President, Safety, Environment& Health
Piedmont Lithium Carolinas, Inc.
1

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request#4
March 15, 2024
Binder 2 of 2 Attachments:
Appendix B— In-Pit Mine Groundwater Monitoring Well Plan
Appendix C— Updated Tabular Document Library
2

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request#4
March 15, 2024
1. Please provide a response to the enclosed comments from the Mooresville Regional office.
See Binder 1 of 2 for this response.
2. In your response to item 5 of your Additional Request for additional information dated January
18, 2023, states that you propose to evaluate real time monitoring data of the water generated
from the above ground waste rock pile to inform decisions for the in-pit waste rock system and
rely on 12 months of data before developing a plan for monitoring and treatment of the in-pit
waste rock. The above ground waste rock pile, exposed primarily to rainwater, will exist in a
different environment than the in-pit waste rock system, exposed both to rainwater and
groundwater once the water table equalizes post dewatering. Data from the above ground waste
rock pile may act as a supplement to the proposed in-pit waste rock system, however in order
to evaluate any potential unduly adverse effects on potable groundwater supplies or standards
groundwater quality, please provide a monitoring plan for the in-pit waste rock system.
Please see Appendix B for PLCI's In-Pit Mine Groundwater Monitoring Well Plan.
Additional Information Provided (not requested as part of ADI #4)
Tabular Document Library
In the response to ADI#3, PLCI provided a Tabular Document library of documents provided during the
mine permit application review process. With the provision of this ADI#4, an updated Tabular Document
Library to reflect information herein is provided in Appendix C.
3

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request#4
March 15, 2024
This page intentionally left blank.
4

Piedmont Lithium Carolinas, Inc. I Response to Additional Information Request#4
Appendix B— In-Pit Mine Groundwater Monitoring Well Plan
PIEDMONT
LITHIUM
Appendix B — In-Pit Mine
Groundwater Monitoring Well
Plan

Piedmont Lithium Carolinas, Inc. I Response to Additional Information Request#4
Appendix B—In-Pit Mine Groundwater Monitoring Well Plan
This page intentionally left blank.
6

I n-Pit Mine
•
Groundwater
Monitoring Wel I
Plan
Carolina Lithium Project
Piedmont Lithium Carolinas, Inc.
Gaston County. North Carolina
March 12, 2024

Page intentionally left blank.

Piedmont Lithium Carolinas, Inc. I Carolina Lithium
Table of Contents
Table of Contents
Certification................................................................................................................................iii
1 Introduction......................................................................................................................... 1
2 In-Pit Mine Groundwater Monitoring.................................................................................... 1
2.1 In-Pit Groundwater Monitoring Well Network................................................................ 1
2.2 Groundwater Level Monitoring ..................................................................................... 4
2.3 Groundwater Quality Monitoring................................................................................... 4
2.3.1 Baseline Monitoring .............................................................................................. 4
2.3.2 Compliance Monitoring ......................................................................................... 4
2.3.3 Monitoring Parameters.......................................................................................... 5
3 Other Considerations.......................................................................................................... 6
Table of Tables
Table 1. Proposed In-Pit Groundwater Monitoring Well Network................................................ 1
Table 2. Proposed Monitoring Parameters................................................................................. 5
Table of Figures
Figure 1. In-Pit Groundwater Monitoring Well Network............................................................... 2
i

Page intentionally left blank.
H

Piedmont Lithium Carolinas,Inc. I Carolina Lithium
Certification
Certification
I, Mark P. Filardi, a Licensed Geologist in the State of North Carolina, do certify that the
information contained in this report is correct and accurate to the best of my knowledge. HDR
Engineering, Inc. of the Carolinas is a professional corporation licensed to practice geology in
the State of North Carolina (License No. C-503).
Mark P. Filardi, LG #1886
Senior Geologist
r
SEA
1886 W
9�Rousso
M.P�
iii

Piedmont Lithium Carolinas,Inc. I Carolina Lithium
Introduction
1 Introduction
The North Carolina Department of Environmental Quality (NCDEQ)— Division of Energy, Mineral,
and Land Resources (DEMLR) issued an Additional Information Request#4 (ADI#4)on February
9, 2024, which requested a monitoring plan for the in-pit waste rock system to evaluate potential
effects on potable groundwater supplies and groundwater quality.
Piedmont Lithium Carolinas, Inc. (PLCI) presents the following plan for groundwater monitoring
of the in-pit waste rock system. Note that this water quality monitoring plan (WQMP) is based on
available information at the time of preparation; as additional data becomes available (e.g., 12
months of data from waste rock pile monitoring), this WQMP may be revisited and revised, as
necessary.
2 In-Pit Mine Groundwater Monitoring
Groundwater monitoring in the vicinity of planned mine pits will commence up to one year prior to
mine operation to provide baseline groundwater level and quality data. Monitoring will continue
throughout mine operation to monitor potential changes in groundwater levels and quality from
dewatering activities, as they relate to potable groundwater supplies beyond the mine permit
boundary.
Well locations were selected based on permitted area, planned pit extents, proximity to known or
suspected private water supply wells, and spatial coverage. Monitoring of deep (bedrock) and
shallow (overburden) intervals is proposed at locations to align with the anticipated extent of
drawdown estimated by three-dimensional groundwater flow modeling.'
2.1 In-Pit Groundwater Monitoring Well Network
Four deep(bedrock) monitoring locations and 15 paired deep(bedrock)and shallow(overburden)
monitoring locations are proposed around the pits to monitor groundwater quality in the bedrock
and overburden aquifers (Table 1 and Figure 1).
Table 1. Proposed In-Pit Groundwater Monitoring Well Network
OB-1D/OB-1S OB-8D OB-24D/OB-24S
OB-2D/OB-2S OB-9D/OB-9S OB-25D
OB-3D/OB-3S OB-10D/OB-10S OB-26D/OB-26S
OB-4D/OB-4S OB-11 D/OB-11 S OB-27D/OB-27S
OB-5D/OB-5S OB-14D/OB-14S OB-28D
OB-6D/OB-6S OB-15D/OB-15S
OB-7D OB-23D/OB-23S
Note:D=deep(bedrock)well;S=shallow(overburden)wells
Technical Memorandum—Groundwater Model Update. Prepared by HDR,dated November 16,2023.
1

^• •
~ `SMe AN to
�^ ,.q� O�tl.�•af l' - \ . 1 � y�y L e - �r
• v �o l ba h Church Rd-d f M1
r '` tlePliz
FLa
PhzibahC
r d
IN
Ry -- j�� .�♦♦♦♦♦♦♦♦Q♦� ��♦♦♦♦♦♦♦♦♦♦♦♦♦♦♦�♦jI • : D
1, r, ♦ ♦♦1� ��♦♦ ♦♦♦♦♦♦♦♦♦♦♦♦�►♦♦♦♦♦Ii
d!Penters.54;a` =',•P • - ♦�♦♦ ♦♦♦♦♦♦♦♦ ♦♦♦
w �r i♦♦♦♦♦♦♦�►♦♦ ♦♦ ��►♦♦
'~ A - ' .mod ; t /, •♦♦♦♦♦♦♦�♦♦ ♦♦ ♦♦♦•' • - • -
• •. : pays Sv`` •
4.11
x 9-11/ :.,

Piedmont Lithium Carolinas,Inc. I Carolina Lithium
In-Pit Mine Groundwater Monitoring
Page intentionally left blank.
3

Piedmont Lithium Carolinas,Inc. I Carolina Lithium
In-Pit Mine Groundwater Monitoring
2.2 Groundwater Level Monitoring
For up to one year prior to mine operation, and throughout the life of the mine, water levels will
be monitored in deep and shallow groundwater monitoring wells via dedicated data loggers. The
purposes of water level monitoring will be to evaluate seasonal fluctuations prior to operation and
potential pumping-induced variation during mine operation.
As proposed in the Water Supply Well Mitigation Plan (Appendix A of the Technical Memorandum
—Groundwater Model Update, dated November 16, 2023) submitted to DEMLR as part of the ADI
#3 response, graphs of water level change over time shall be used by PLCI and NCDEQ to
evaluate if groundwater withdrawals have potential to affect usability of private water supply wells
beyond the permitted mine boundary.
2.3 Groundwater Quality Monitoring
Water quality monitoring will consist of baseline monitoring to establish site-specific constituent
concentrations prior to mine operation, followed by periodic compliance monitoring to evaluate
potential effects of mining on groundwater quality.
2.3.1 Baseline Monitoring
PLCI proposes to install the proposed groundwater monitoring wells around the pits to facilitate
sampling of groundwater in the deep (bedrock) and shallow (overburden) aquifers. Baseline
monitoring will be conducted on a monthly basis for one year prior to mine operation to obtain
background groundwater quality data representative of seasonal fluctuations in groundwater
geochemistry. The data will be used to evaluate naturally occurring concentrations of constituents
(e.g., arsenic) as a baseline for developing statistically derived site-specific background threshold
values (BTVs)for groundwater. Statistically derived BTVs will be compared to established criteria
(Ground Water Quality Standards in 15A NCAC 02L [21L Standards]) to propose site-specific
target limits (SSTLs) for each monitored constituent identified in Table 2.
These data may be used to request support future changes to groundwater sampling parameters
and frequency during mining operations, as applicable.
2.3.2 Compliance Monitoring
PLCI proposes to conduct quarterly sampling of the in-pit mine groundwater monitoring well
network once mining operations commence. The results would be compared to SSTLs and/or 2L
Standards to evaluate compliance. PLCI proposes to continue quarterly sampling of the in-pit
mine groundwater monitoring well network through the life of mine and for two (2)years after mine
pits have been backfilled and reclaimed. After this period, sampling frequency may be reduced or
eliminated depending on the results of the monitoring program and with approval of NCDEQ.
4

Piedmont Lithium Carolinas,Inc. i Carolina Lithium
In-Pit Mine Groundwater Monitoring
2.3.3 Monitoring Parameters
Parameters commonly required in mining applications, those listed in the NCG02 General Permit
for Lithium Ore Mining, and results of the LEAF and humidity cell test work,2 form the basis for
groundwater quality monitoring around the pits (Table 2).
Table 2. Proposed Monitoring Parameters
Parameter* Field or Lab Method* Rationale
Parameter
pH Field Water Quality Meter Common for mining applications;indicator for
potential solubility of metals
Water level Field Water Level Meter Common for mining applications;
representative nature of sampling feasibility
Turbidity Field Water Quality Meter Common for mining applications;listed in
NCG02 for lithium ore mines
Specific Conductance Field Water Quality Meter Common for water quality sampling events
Temperature Field Water Quality Meter Common for water quality sampling events
Dissolved Oxygen Field Water Quality Meter Common for water quality sampling events
Based on results from LEAF and/or humidity
Total Aluminum Lab EPA 200.7 cell tests;common for mining applications;
listed in NCG02 for lithium ore mines
Total Manganese Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Total Nickel Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Total Cadmium Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Based on results from LEAF and/or humidity
Total Cobalt Lab EPA 200.7 cell tests
Total Lead Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Total Arsenic Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Total Chromium Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Total Iron Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Total Zinc Lab EPA 200.7 Based on results from LEAF and/or humidity
cell tests
Based on results from LEAF and/or humidity
Total Vanadium Lab EPA 200.7 cell tests
Total Lithium Lab EPA 200.8 Based on results from LEAF and/or humidity
cell tests
Total Fluoride Lab EPA 300.0 Listed in NCG02 for lithium ore mines
Nitrate/Nitrite N Lab EPA 353.2 Common for mining applications;indicator of
blasting agents
Ammonia N Lab EPA 350.1 Common for mining applications;indicator of
blasting agents
Total Organic Carbon Lab SM 5310 Indicator of Total Petroleum Hydrocarbons
(TOC) (TPH)
Parameters should be analyzed utilizing laboratory methods with detection limits less than regulatory standards,as applicable.
2 Leaching Environmental Assessment Framework(LEAF)and Accelerated Weathering of Solid Materials Using a Modified
Humidity Cell(ASTM D 5744-96)Collaboration Technical Summary(dated April 2023); prepared by Marshall Miller&Associates.
5

Piedmont Lithium Carolinas,Inc. I Carolina Lithium
Other Considerations
3 Other Considerations
PLCI believes that parameters proposed in Table 2 are adequate to effectively monitor
groundwater quality of the in-pit waste rock system. Significant testing of expected pit backfill
materials generated during bench-scale testing (waste rock and concentrator tailings) was
conducted to support the mine permitting process. This testing focused on evaluating leachability
of metals, radiological constituents, and general chemistry parameters in mine waste rock
materials via LEAF,toxic characteristic leaching procedure(TCLP), and humidity cell testing. Note
that since the materials tested were solids, the results of testing are most applicable to material
that may be used as pit backfill once pit backfill operations commence.
Based on these results, the following parameters were not selected for testing during baseline or
compliance monitoring:
• Uranium: North Carolina does not have surface or groundwater regulatory standards for
uranium; however, the United States Environmental Protection Agency (USEPA) has
established a Maximum Contaminant Level (MCL)of 30 lag/L for uranium in public drinking
water. All three leachability tests detected uranium well below the USEPA MCL. In the test
work conducted to date, the highest uranium concentration reported was 12.2 tag/L during
week 1 of a 20-week humidity cell test. Uranium was also detected in TCLP and LEAF
samples at maximum concentrations of 7.466 lag/L and 5.30 lag/L, respectively. In
comparison, naturally occurring uranium has been detected in groundwater within the
Piedmont Physiographic Region of North Carolina at concentrations ranging from 5.1-10.0
lag/L.3 Thus, the uranium leaching results are consistent with the levels of naturally
occurring uranium in groundwater in this region.
• Thorium: North Carolina also does not have surface or groundwater standards for thorium,
nor does the USEPA have an MCL for thorium. Given that thorium is present in trace
quantities in virtually all rock, soil, and water, PLCI included thorium in the test work
program conducted to support the mine permitting process. Thorium was detected at
concentrations ranging from 0.1 to 1.2 lag/L in TCLP and humidity cells tests, marginally
above the laboratory reporting Iimit4 (0.1 lag/L) and was not detected above the laboratory
reporting limit of 5.0 lag/L in LEAF samples.
Based on these low-level occurrences below regulatory criteria that are generally consistent with
naturally occurring concentrations in groundwater, radiological parameters are not proposed as
part of the routine in-pit groundwater monitoring plan.
3 Coyote, R.and Vengosh,A.2020. Factors controlling the risks of co-occurrence of the redox-sensitive elements of arsenic,
chromium,vanadium,and uranium in groundwater from the eastern United States. Environmental Science&Technology,54(7),
4367-4375. [URL]https://doi.org/10.1021/acs.est.9bO6471.
4 Laboratory reporting limit is defined as the smallest concentration of a chemical that can be reported by a laboratory. Detection
above a laboratory reporting limit is not necessarily indicative of an exceedance of a regulatory standard(e.g., MCL).Regulatory
standards are typically one or more orders of magnitude greater than the laboratory reporting limit.
6

FN
440 S Church Street
Suite 1200
Charlotte, NC 28202-2075
[phone]
hdrinc.com
©2024 HDR, Inc., all rights reserved

Piedmont Lithium Carolinas, Inc. I Response to Additional Information Request#4
Appendix C — Updated Tabular Document Library
PIEDMONT
LITHIUM
Appendix C — Updated
Tabular Document Library

Piedmont Lithium Carolinas, Inc. I Response to Additional Information Request#4
Appendix C— Updated Tabular Document Library
This page intentionally left blank.
8

Identifying Attchment DEMLR Receipt
Document Name Most Recent Version
(if applicable) Date
Cover Letter,Mine Application,and Figures 8/31/2021 Mine Permit Application:Cover Letter,Mine Permit Application,and Figures
Overall Site Plan Map and Reclamation Map(Sheets 1-2) Appendix A 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Associated Concentrate Operations Drawings(Sheets 1-34) Appendix B 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Associated Lithium Hydroxide Conversion Plant Drawings(Sheets 1-18) Appendix C 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Supporting Concentrate Operations Documentation Appendix D
Piedmont Lithium Carolinas Mine#1 Pit Sequencing Specifications(Sheets 1-4) Appendix D.1 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Road and Conveyor Construction Specifications Appendix D.2 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Ditch General Construction Specifications Appendix D.3 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Sediment Structures and General Construction Specifications Appendix DA 8/31/2021 ADI#4 Response:ES&C Detailed Drawings
Guideline Technical Specifications for Waste Rock Disposal Area Appendix D.5 8/31/2021 ADI#3 Final Response:Appendix D-Appendix C
Drainage Calculations(Concentrate Operations) Appendix D.6 8/31/2021 ADI#2 Partial Response:Appendix B-Attachment 1 and
ADI#3 Final Response:Appendix C(for waste rock pre-construction only)
Mine Waste Rock and Topsoil Pile Stability Analysis Appendix D.7 8/31/2021 ADI#1 Response:Appendix G-Attachment 3.7
Supporting Lithium Hydroxide Conversion Plant Documentation Appendix E
NC Mine Permit
Road,Parking,Walls, Fencing,and Stream Crossing Construction Specifications Appendix E.1 8/31/2021 ADI#1 Response:Appendix G-Attachment 5.1
Application Rail Construction Specifications Appendix E.2 8/31/2021 ADI#1 Response:Appendix G-Attachment 5.2
Drainage and Sediment Structure Specifications Appendix E.3 8/31/2021 ADI#1 Response:Appendix G-Attachment 5.3
Drainage Calculations(Lithium Hydroxide Conversion Plant) Appendix EA 8/31/2021 ADI#2 Partial Response:Appendix B-Attachment 2
Technical Memorandum-Water Quality Testing Appendix F 8/31/2021 Mine Permit Application:Appendix F
Summary of Waste Rock and Process Tailings Geochemical Assessment—Piedmont Lithium Project Appendix G 8/31/2021 Mine Permit Application:Appendix G(valid for waste rock testwork discussion only);
ADI#2 Final Response:Appendix F is more re resetative of concentrator tailings testwork discussion
Technical Memorandum-Groundwater Model Appendix H 8/31/2021 ADI#3 Final Response:Appendix C
Acid Base Account ABA and Toxicity Characteristic Leaching Procedure TCLP Test Results Summary, Mine Permit Application:Appendix I(still valid with the exception of Proposed Mitigation discussion;proposed
(ABA) y g ( ) ry,and Proposed Mitigation Appendix 1 8/31/2021 mitigation related to potentially acid generating rock is no longer applicable due to results of
Plan Associated with Potentially Acid Producing Waste Rock in the Southern Portion of East Pit ADI#2 Final Response:Appendix F which showed that acidic conditions are no longer expected)
Technical Memorandum Toxicity Testing of Lithium Hydroxide Conversion Tailings Appendix J 8/31/2021 See Note 1 (below)
Technical Memorandum-Evaluation of Mine Pit Operations on Water Quality Appendix K 8/31/2021 Mine Permit Application:Appendix K(still valid with the exception of chemical conversion plant tailings discussion
which is no longer applicable,see Note 1)
Section 404/401 Individual Permit Approvals Appendix L 8/31/2021 Mine Permit Application:Appendix L
Required Adjoining Landowner Notification Appendix M 8/31/2021 Mine Permit Application:Appendix M
Courtesy Adjoining Landowner Notification Appendix N 8/31/2021 Mine Permit Application:Appendix N
Land Entry Agreements Appendix O 8/31/2021 Mine Permit Application:Appendix O
Note 1:Chemical conversion plant tailings(also referred to as analcime)are no longer proposed to be placed in either the waste rock pile or as backfill in the pits.

Identifying Attchment DEMLR Receipt
Document Name Most Recent Version
(if applicable) Date
Cover Letter and ADI Responses 12/17/2021 ADI#1 Response Cover Letter and ADI Responses
MSD Sheets Appendix A 12/17/2021 ADI#1 Response:Appendix A
General Heavy Media Circuit Simplified Appendix B 12/17/2021 ADI#1 Response:Appendix B
Water Supply Well Mitigation Plan Appendix C 12/17/2021 ADI#3 Final Response:Appendix C-Appendix A
Proof of NCG02 Notice of Intent Application Submittal Appendix D 12/17/2021 Not eligible for NCG02 coverage(eligible for Individual NPDES)
see ADI#2 Final Response:Appendix A
Piedmont Lithium Blasting Impact Study Appendix E 12/17/2021 ADI#1 Response:Appendix E
Item D.7-Revegetation Plan(from mine permit application) Appendix F 12/17/2021 ADI#1 Response:Appendix F
Response to DEMLR MRO Comments Appendix G
Response to DEMLR MRO Comments Responses 12/17/2021 ADI#1 Response:Appendix G Responses
Overall Mine Map and Reclamation Map(Sheets 1-2) Attachment 1 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
Concentrate Operation Drawings(Sheets 1-34) Attachment 2 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
Supporting Concentrate Operations Documentation Attachment 3
Piedmont Lithium Carolinas Mine#1 Pit Sequencing Specifications(Sheets 1-4) Attachment 3.1 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
Road and Conveyor Construction Specifications Attachment 3.2 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
Ditch General Construction Specifications Attachment 3.3 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
ADI#1 Sediment Structures and General Construction Specifications Attachment 3.4 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
Response to
DEMLR Guideline Technical Specifications for Waste Rock Disposal Area Attachment 3.5 12/17/2021 ADI#3 Final Response:Appendix D-Appendix C
Drainage Calculations(Concentrate Operations) Attachment 3.6 12/17/2021 ADI#2 Partial Response:Appendix B-Attachment 1 and
ADI#3 Final Response:Appendix C(for waste rock pre-construction only)
Mine Waste Rock and Topsoil Pile Stability Analysis Attachment 3.7 12/17/2021 ADI#1 Response:Appendix G-Attachment 3.7
Lithium Hydroxide Conversion Plant Drawings(Sheets 1-20) Attachment 4 12/17/2021 ADI#4 Response:ES&C Detailed Drawings
Supporting Conversion Operations Documentation Attachment 5
Road,Parking,Walls,Fencing,and Stream Crossing Construction Specifications Attachment 5.1 12/17/2021 ADI#1 Response:Appendix G-Attachment 5.1
Rail Construction Specifications Attachment 5.2 12/17/2021 ADI#1 Response:Appendix G-Attachment 5.2
Drainage and Sediment Structure Specifications Attachment 5.3 12/17/2021 ADI#1 Response:Appendix G-Attachment 5.3
Drainage Calculations(Lithium Hydroxide Conversion Plant) Attachment 5.4 12/17/2021 ADI#2 Partial Response:Appendix B-Attachment 2
Two Rivers Utilities Letter to Piedmont Lithium Appendix H 12/17/2021 ADI#2 Final Response:Appendix C-Attachment 2
Technical Memorandum-WWTP Considerations Appendix 1 12/17/2021 ADI#2 Final Response:Appendix C-Attachment 1
Figure-Groundwater Observation Wells and Stream Flow Monitoring Locations Appendix J 12/17/2021 ADI#3 Final Response:Appendix C-Appendix A
Federally and State Threatened and Endangered Species Survey Appendix K 12/17/2021 ADI#1 Response:Appendix K
Archaeological Survey of the Carolina Lithium Mine Project Expansion Gaston County,NC Appendix L 12/17/2021 ADI#2 Partial Response:Appendix D
Response to Division of Water Resources-Industrial Permitting Unit Comment#3 Appendix M 12/17/2021 ADI#1 Response:Appendix M(valid for waste rock test work discussion only);ADI#2 Final Response:Appendix
F is more represetative of concentrator tailings test work discussion.

Identifying Attchment DEMLR Receipt
Document Name Most Recent Version
(if applicable) Date
Cover Letter and ADI Responses 6/21/2022 ADI#2 Partial Response:Cover Letter and ADI Responses
Water Supply Well Mitigation Plan(revised) Appendix A 6/21/2022 ADI#3 Final Response:Appendix C-Appendix A
Mooresville Regional Office Comments Appendix B
Mooresville Regional Office Comments Responses 6/21/2022 ADI#2 Final Response:Appendix B Response
Concentrator Plant Drainage Calculations Attachment 1 6/21/2022 ADI#2 Partial Response:Appendix B-Attachment 1 and
ADI#3 Final Response:Appendix C for waste rock re-construction only)
Conversion Plant Drainage Calculations Attachment 2 6/21/2022 ADI#2 Partial Response:Appendix B-Attachment 2
Piedmont Lithium Detailed Drawings(attached separately as a planset) Attachment 3 6/21/2022 ADI#4 Response:ES&C Detailed Drawings
DWR-WQPS Comments Apppendix C
ADI#2 Partial
Response to DWR-WQPS Comments Responses 6/21/2022 ADI#2 Final Response:Appendix C Responses
DEMLR Concentrate Operation Drawings(Sheets 1-34) Attachment 1 6/21/2022 ADI#4 Response:ES&C Detailed Drawings
(was not in compiled ADI#1 PDF submittal,so provided in ADI#2 PDF submittal)
Archaeological Survey of the Carolina Lithium Mine Project Expansion Gaston County,NC Appendix D 6/21/2022 ADI#2 Partial Response:Appendix D
Waste Rock Pit Backfill Plan-South and East Pits-Technical Specifications Appendix E 6/21/2022 ADI#2 Final Response:Appendix E
Solid and Liquid Waste Flowsheets Appendix F
Overall Site Solid Waste Flowsheet Attachment 1 6/21/2022 ADI#2 Partial Response:Appendix F-Attachment 1
Overall Site Liquid Waste Flowsheet Attachment 2 6/21/2022 ADI#2 Partial Response:Appendix F-Attachment 2
DRAFT Response to Select Portions of ADI#2 from DEMLR Permit Review Process 9/27/2022 ADI#2 Final Response:Appendix
Piedmont Lithium Detailed Drawings-Revised Planset per MRO Comments 2/24/2023 ADI#4 Response:ES&C Detailed Drawings
2 electronic volumes,but printed as one bound set 2 copies)
Cover Letter and ADI Responses 5/1/2023 ADI#2 Final Response:Cover Letter and AD
NPDES Permit Application Acknowledgement Receipts Appendix A 5/1/2023 ADI#2 Final Response:Appendix A
Updated Response to MRO Comments from January 14,2022 IF Appendix B 5/1/2023 ADI#2 Final Response:Appendix B
Updated Response to DWR-WQPS Comments from January 14,2022 Appendix C
Updated Response to DWR-WQPS Comments from January 14,2022 Responses 5/1/2023 ADI#2 Final Response:Appendix C Responses
Technical Memorandum-WWTP Considerations Update Attachment 1 5/1/2023 ADI#2 Final Response:Appendix C-Attachment 1
ADI#2 FINAL Technical Memorandum-Carolina Lithium Wastewater Characterization Attachment 1 5/1/2023 ADI#2 Final Response:Appendix C-Attachment 1
Response to PLCI Letter to Two Rivers Utilities Attachment 2 5/1/2023 ADI#2 Final Response:Appendix C-Attachment 2
DEMLR
Two Rivers Utilities Response Attachment 2 5/1/2023 ADI#2 Final Response:Appendix C-Attachment 2
LEAF and Accelerated Weathering of Solid Materials Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Attachment 3 5/1/2023 ADI#2 Final Response:Appendix C-Attachment 3
Summary
Air Quality Permit Completeness Letter Appendix D 5/1/2023 ADI#2 Final Response:Appendix D
Waste Rock Pit Backfill Plan-South and East Pits-Technical Specifications Appendix E 5/1/2023 ADI#2 Final Response:Appendix E
LEAF and Accelerated Weathering of Solid Materials Using a Modified Humidity Cell(ASTM D 5744-96)Collaboration Technical Appendix F 5/1/2023 ADI#2 Final Response:Appendix F
Summary
Proposed Mitigation Plan for Above-Ground Waste Rock Pile with Supporting Information Appendix G 5/1/2023 ADI#3 Final Response:Appendix D-Appendix C
Cover Letter and Partial Responses 9/7/2023 ADI#3 Partial Response:Cover Letter and Partial Responses
Liner Basis of Design Package DRAFT(attached separately) attached separately 9/7/2023 ADI#3 Final Response:Appendix D
ADI#3 Partial Geotechnical Engineering Report for Piedmont Concentrator Definitive Feasiblity Study Project Appendix A 9/7/2023 ADI#3 Final Response:Appendix D-Appendix A
DRAFT
Response to Operational Details on Waste Rock Pile Construction and Sequencing DRAFT Appendix B 9/7/2023 ADI#3 Final Response:Appendix D-Appendix B
DEMLR Waste Rock Pile Monitorig and Treatment Plan DRAFT Appendix C 9/7/2023 ADI#3 Final Response:Appendix D-Appendix C
Sediment Basin GCL Equivalency Appendix D 9/7/2023 ADI#3 Final Response:Appendix D-Appendix D
Liner Sequencing Drawings DRAFT(attached separately) attached separately 9/7/2023 ADI#3 Final Response:Liner System Basis of Design Sequencing Drawings

Identifying Attchment DEMLR Receipt
Document Name Most Recent Version
(if applicable) Date
Cover Letter and ADI Responses 1/18/2024 ADI#3 Final Response:Cover Letter and ADI Responses
Monitoring Well Construction Plan Appendix A 1/18/2024 ADI#3 Final Response:Appendix A
Email from DEMLR Appendix B 1/18/2024 ADI#3 Final Response:Appendix B
Technical Memorandum-Groundwater Model Update Appendix C 1/18/2024 ADI#3 Final Response:Appendix C
Water Supply Well Mitigation Plan Appendix A 1/18/2024 ADI#3 Final Response:Appendix C-Appendix A
Liner System Basis of Design Appendix D 1/18/2024 Provided via lWee Note 2)
Geotechnical Engineerng Report for Piedmont Concentrator Definitive Feasibility Study Project Appendix A 1/18/2024 Appendix A(Provided via Email[See Note 2])
ADI#3 FINAL Details on Waste Rock Pile Construction and Sequencing Appendix B 1/18/2024 Appendix B(Provided via Email[See Note 2])
Response to Waste Rock Pile Monitoring and Treatment Plan Appendix C 1/18/2024 Corrected Appendix C within Liner System Basis of Design(Provided via Email[See Note 2])
DEMLR Sediment Basin GCL Equivalency Appendix D 1/18/2024 Appendix D(P ovided via Email[See Note 2])
Liner System Basis of Design Sequencing Drawings("Liner Sheets")(attached separately) attached separately 1/18/2024 ADI#3 Final Response:Liner System Basis of Design Sequencing Drawings
Tabular Document Library Appendix E 1/18/2024 ADI#4 Response:Appendix C
Skimmer Calculation Tables Appendix F 1/18/2024 ADI#3 Final Response:Appendix F
Concentrator Plant Skimmer Design Tables Attachment 1 1/18/2024 ADI#4 Response:Appendix A-Attachment 1
Conversion Plant Skimmer Design Tables Attachment 2 1/18/2024 ADI#4 Response:Appendix A-Attachment 2
Drainage Calculations for Concentrate Operations-Waste Rock Pile(Pre-Construction Phase Only) Appendix G 1/18/2024 ADI#3 Final Response:Appendix G
ES&C Detailed Drawings("ES&C Sheets")(attached separately) attached separately 1/18/2024 ADI#4 Response:ES&C Detailed Drawings
Identifying Attchment DEMLR Receipt
Document Name Most Recent Version
(if applicable) Date
Cover Letter 3/12/2024 Cover Letter(See Note 2)
Liner System Basis of Design 3/12/2024 Provided via Email(See Note 2)
Geotechnical Engineerng Report for Piedmont Concentrator Definitive Feasibility Study Project Appendix A 3/12/2024 Appendix A(Provided via Email[See Note 2])
Via Email Details on Waste Rock Pile Construction and Sequencing Appendix B 3/12/2024 Appendix B(Provided via Email[See Note 2])
Waste Rock Pile Monitoring and Treatment Plan Appendix C 3/12/2024 Corrected Appendix C within Liner System Basis of Design(Provided via Email[See Note 2])
Sediment Basin GCL Equivalency Appendix D 3/12/2024 Appendix D(Provided via Email[See Note 2])
Note 2:The"Section 4 Other Considerations"in the Waste Rock Pile Monitoring and Treatment Plan(Appendix C of the Liner System Basis of Design)needed revisions;therefore,the Liner System Basis of Design document is being reissued with the corrections made in Appendix C. No other revisions
were made to the Liner System Basis of Design document.
Identifying Attchment DEMLR Receipt
Document Name Most Recent Version
(if applicable) Date
Cover Letter and ADI Responses 3/15/2024 ADI#4 Response:Cover Letter and ADI Responses
MRO Comments for Piedmont Lithium Response to ADI#3 Appendix A 3/15/2024 ADI#4 Response:Appendix A
ADI#4 Concentrator Plant Skimmer Design Tables Attachment 1 3/15/2024 ADI#4 Response:Appendix A-Attachment 1
Response to Conversion Plant Skimmer Design Tables Attachment 2 3/15/2024 ADI#4 Response:Appendix A-Attachment 2
DEMLR In-Pit Groundwater Monitoring
Well Plan Appendix B 3/15/2024 ADI#4 Response:Appendix B
Tabular Document Library Appendix C 3/15/2024 ADI#4 Response:Appendix C
ES&C Detailed Drawings("ES&C Sheets")(attached separately) attached separately 3/15/2021 ADI#4 Response:ES&C Detailed Drawings