01_Final Response to DEMLR ADI No 2

P I E DM0 N T Piedmont Lithium Carolina, Inc.
42 E Catawba St.
LITHIUM Belmont, NC 28012
April 27, 2023
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, dated January 14, 2022
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.
In PLCI's June 20, 2022 response to ADI#2, there were items for which studies,
applications, or agency coordination were ongoing and/or under review and were
therefore deemed incomplete. Therefore, PLCI would like to thank DEMLR for granting
PLCI an extension until May 1 , 2023 to provide responses to ADI#2 items deemed
incomplete from our June 20, 2022 response.
Please see the following responses to the incomplete items from ADI#2. 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 Monique Parker at [phone] or
mparker(a)_piedmontlithium.com.
Yours truly,
J. Monique Parker, CSP
Senior Vice President, Safety, Environment & Health
Piedmont Lithium Carolinas, Inc.

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
Appendices:
Appendix A: NPDES Permit Application Acknowledgement Receipts
Appendix B: Updated Response to MRO Comments from January 14, 2022
Appendix C: Updated Response to DWR-WQPS Comments from January 14, 2022
Appendix D: Air Quality Permit Completeness Letter
Appendix E: Waste Rock Pit Backfill Plan South and East Pits Technical Specifications
Carolina Lithium Project Piedmont Lithium Carolinas, Inc., Gaston County,
North Carolina
Appendix F: Leaching Environmental Assessment Framework (LEAF) and Accelerated
Weathering of Solid Materials Using a Modified Humidity Cell (ASTM D
5744-96) Collaboration Technical Summary
Appendix G: Proposed Mitigation Plan for Above-Ground Waste Rock Pile with
Supporting Information Carolina Lithium Project Piedmont Lithium
Carolinas, Inc., Gaston County, North Carolina
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Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
For the following items, the Division still has questions concerning the
Company's December 16, 2021, reply to the Division's October 29, 2021,
Additional Information Letter [ADI#1]. All other items from the October 29, 2021
have been resolved.
Item 3. Supply proof that the company has applied for NCG02 Stormwater Permit.
PLCI Reply: A statement that they applied for the permit.
Review: DEMLR-Stormwater Program reviewed the application and found
the site did not qualify for the NCG02. The Stormwater Program
did inform the Company by letter that the Company needs to get
an Individual NPDES permit.
Status: The Company will need to supply proof that an Individual NPDES
Permit has been received for the mine site.
PLCI June 20, 2022 Response:
PLCI is currently awaiting results from Leaching Environmental Assessment Framework
(LEAF) testing so a determination can be made in collaboration with DEMLR-
Stormwater Program and DWR-WQPS as to the type of permit required.
Update April 27, 2023:
PLCI submitted two separate NPDES Individual permits for the Carolina Lithium Project
site. One NPDES permit covers the Lithium Mine/Concentrate Operations and one
NPDES permit covers the Lithium Hydroxide Conversion Plant. Both permits were
submitted to the Division of Water Resources — Water Quality Permitting Section on
December 28, 2022. They are both currently under review by DWR-WQPS.
Application acknowledgement receipts for both applications can be found in Appendix
A.
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Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
For the following items, the Division requires clarification on PLCI's December 16,
2021 response to information requested by agencies, Departments or Division:
Item 1: MRO comments concerning the submitted erosion and sedimentation
control plans.
PLCI Reply: PLCI submitted revised drawings.
Review: MRO still has concerns regarding the plans. PLCI need to contact
Zahid Khan, Mooresville Regional Engineer at 704-235-2145 to
resolve their concerns with the plan.
PLCI June 20, 2022 Reply:
After consultation with the Mooresville Regional Office (MRO) team including Zahid
Khan on February 3, 2022, PLCI was able to gain a better understanding of their
concerns with previously provided information. The list included items such as
connection between the drawings, the lack of skimmers within the design and other
administrative items. MRO feedback has been addressed in the updated drawings.
Update April 27, 2023:
PLCI was notified on October 12, 2022 of further comments from MRO on the drawings
provided in the June 20, 2022 submittal. PLCI met with MRO and DEMLR on
December 13, 2022 to discuss the feedback and gain alignment on required updates.
All items from the December 2022 discussion have been incorporated into the updated
drawings that were delivered to DEMLR on February 23, 2023.
See Appendix B for an updated response to DWR-MRO comments from January 14,
2022 associated with these drawings.
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Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
Item 2(a & b): Submit copies of agreements between PLCI and publicly owned
sewer operations concerning the liquid waste being discharged
into the sewer system. Supply a chemical analysis of the waste.
PLCI Reply: PLCI submitted a letter and a Technical Memorandum between
PLCI and Two Rivers Utilities, concerning this matter.
PLCI has requested that the materials supplied be treated "as good faith
evidence that ongoing coordination with the local sewer provider is
occurring to discharge their processed wastewater effluent to a POTW with
pretreatment." PLCI did not supply chemical analysis of the waste.
Review: The Division of Water Resources-Water Quality Permitting Section-
NPDES Industrial Permitting Unit (DWR-WQPS) reviewed the
documentation and raise many concerns. Please see the attached
document.
Status: PLCI needs to address DWR-WQPS concerns as presented in the
attached document.
PLCI June 20, 2022 Reply:
See Appendix C (of June 2022 response) for response to DWR-WQPS concerns.
Update April 27, 2023:
Please see Appendix C for an updated response to the DWR-WQPS comments from
January 14, 2022.
Item 4(a): Supply proof the site has received an Air Permit.
PLCI Reply: PLCI is still in the process of applying to Division of Air Quality
for a permit.
Review: PLCI needs to supply proof they have received an air quality
permit for the facility.
PLCI June 20, 2022 Reply:
PLCI has not received an air permit for this site. A pre-application meeting was held with
North Carolina Division of Air Quality on June 13, 2022. Final preparations are being
made to the air permit application which will be submitted no later than early July 2022.
Update April 27, 2023:
PLCI submitted an application for a combined Prevention of Significant Deterioration
(PSD) Construction and Title V operating air quality permit for the integrated Carolina
Lithium project on August 31, 2022. Additional information was provided to Division of
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Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
Air Quality (DAQ) on October 14, 2022 and an updated application on January 4, 2023.
The application is currently under review by the agency.
Please see Appendix D for the completeness determination letter from DAQ.
After further discussion and review of your application, the following issues have
been identified and need to be addressed. It should be noted that the following
represents new requests, and for this reason the amount of time you have to
address all of the issues raised by this letter has been reset to 180-days.
Item 1: To ensure compliance with NCAC §74-53 (4), please provide the PLCI's
plan on how it is going to back fill the East Pit and the South Pit. This plan must
contain as a minimum:
a. Thickness of each lift.
b. The lift will have to be compacted.
1. What percent compaction will be achieved?
2. How will the compaction be measured (type of instrument or test
to be used)?
3. Supply proof that the instrument or test will be adequate to
measure the thickness of the lift to ensure compaction levels have
been achieved.
4. What will be the frequency of the test (amount of surface area per
test)?
5. How will the measurements be recorded?
c. How long will it take the material to achieve 90% of its subsidence?
d. Certify that the plan will ensure that no pools of water on the finished
grading will develop due to subsidence.
e. How the company will address any pools that might develop after final
grading?
PLCI June 20, 2022 Reply:
See Appendix E (of the June 20,2022 response) for the Waste Rock Pit Backfill Plan —
Technical Specifications.
Update April 27, 2023:
PLCI met with DEMLR, Division of Solid Waste and Division of Water on October 4,
2022 to discuss the results from the LEAF testing and implications to the previously
provided plan. Based on the results of the testing, PLCI has decided to remove the
Chemical Plant tailings from the backfill plan. Due to this change the Waste Rock Pit
Backfill Plan has been updated to reflect this change.
6

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
See Appendix E for the updated Waste Rock Pit Backfill Plan South and East Pits
Technical Specifications.
Item 2: Please supply a comprehensive flowsheet showing both solid and liquid
waste discharges from the Separation Plant and the Chemical Plant. The
flowsheet must show at a minimum:
a. A description of the materials including:
I. Any reagents that might be present.
II. The concentration of the reagents.
III. Any product that will degrade and what are the by-products.
b. Worst case, how much of the material would be sent to the waste pile or
the pit hourly and annually?
c. How frequently will the material be sampled and for what parameters?
PLCI June 20, 2022 reply:
See Appendix F (of the June 20, 2022 response) with the corresponding flowsheets for
solid and liquid waste. For solid and liquid waste, details responding to (a) and (b)
above are included in their representative flowsheets.
At this time, we are not able to provide a detailed answer as to what parameters will be
evaluated due to ongoing wastewater analysis work and LEAF testing. Upon receipt of
this data, we will work closely with the designated agency or department to algin on
frequency of sampling (at least quarterly) and parameters to be evaluated.
Update April 27, 2023:
Please see Appendix F — Leaching Environmental Assessment Framework (LEAF) and
Accelerated Weathering of Solid Materials Using a Modified Humidity Cell (ASTM D
5744-96) Collaboration Technical Summary.
Item 3: Please supply proof that PLCI has received all necessary permits required
by DWR- WQPS, or documentation from DWR-WQPS stating that a given
permit is not required.
PLCI June 20, 2022 reply:
PLCI has not received all necessary permits required by DWR-WQPS. We are currently
awaiting results from Leaching Environmental Assessment Framework (LEAF) testing
so a determination can be made in collaboration with DEMLR-Stormwater Program and
DWR-WQPS as to the type of permit required.
7

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
Update April 27, 2023:
PLCI submitted two separate NPDES Individual permits for the Carolina Lithium Project
site. One NPDES permit covers the Lithium Mine/Concentrate Operations and one
NPDES permit covers the Lithium Hydroxide Conversion Plant. Both permits were
submitted to the Division of Water Resources - Water Quality Permitting Section on
December 28, 2022. They are both currently under review by the DWR-WQPS.
Application acknowledgement receipts for both applications can be found in Appendix
A.
Item 4: Your application is inadequate to determine whether the reclamation plan
will prevent leaching of pollutants to groundwater. To avoid triggering
NCAC§74- 51(3), Please provide:
a. A protocol for analyzing all waste products, including the pit waste, to
determine the pH range in which the material will not leach.
b. The number of samples that will be analyzed to achieve statistical
confidence that the pH range is appropriate to prevent leaching.
c. Explain how the waste disposal areas will be zoned/encapsulated to
ensure that if any leachate forms, it will not migrate?
d. How will the waste pile be treated to ensure proper pH control?
PLCI June 20, 2022 reply:
Please find below responses to above questions.
a. PLCI along with MMA and Energy and Environment Innovation joined together
to develop a detailed plan to conduct Leaching Environmental Assessment
Framework (LEAF) testing to analyze all waste products that would be
collected either on the waste rock pile or as backfill into the excavated mine
pits. At this time, all data is not available. Once complete, a technical memo
will be provided highlighting the plan, its results, and proposed management
based on results.
b. The samples that were or are currently being analyzed include:
1. Potentially acid generating (PAG) waste rock
2. Non-PAG waste rock
3. Tailings
4. Various combinations of waste rock and tailings
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Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
In order to show statistical confidence, testing has included testing using
natural and Synthetic Precipitation Leaching Procedure (SPLP). Testing was
also conducted using pH ranges from 9 — 4 including duplicates.
c. Once results are received, we will be able to provide an answer to this
question.
d. Once results are received, we will be able to provide an answer to this
question.
Update April 27, 2023:
Please see Appendix F - Leaching Environmental Assessment Framework (LEAF) and
Accelerated Weathering of Solid Materials Using a Modified Humidity Cell (ASTM D
5744-96) Collaboration Technical Summary
To further ensure the proper measures are in place, PLCI has created a Proposed
Mitigation Plan for Above-Ground Waste Rock Pile with Supporting Information. This
plan can be found at Appendix G.
9

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
April 27, 2023
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Appendix A — NPDES
Permit Application
Acknowledgement
Receipts

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Appendix B — Updated
Response to MRO
Comments from January
1472022

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Appendix C — Update
Response to DWR-WQPS
Comments from January
1472022

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Appendix D — Air Quality
Permit Completeness
Letter

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Appendix E — Waste Rock
Pit Backfill Plan South and
East Pits Technical
Specifications

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Appendix F — LEAF and
Accelerated Weathering of
Solid Materials Using a
Modified Humidity Cell
(ASTM D 5744-96)
Collaboration Technical
Summary

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Appendix G — Proposed
Mitigation Plan for Above-
Ground Waste Rock Pile
with Supporting
Information

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