20211215_Response to DEMLR ADI

PIEDtAONT
L I T H I U M
Responseto
DEMLR Additional
Information
Request (dated October 29, 2021)
Carolina Lithium Project
Piedmont Lithium Carolinas, Inc.
Gaston County, North Carolina
December 15, 2021

PIEDMONT
LITHIUM
December 16, 2021
Mr. David Miller, PE
NC Department of Environmental Quality
Division of Energy, Mineral, and Land Resources
1612 Mail Service Center
Raleigh, NC 27699-1612
Piedmont Lithium Carolinas, Inc.
32N Main Street Suite 100
Belmont, NC 28012
SUBJECT: Piedmont Lithium Carolinas, Inc.
Carolina Lithium Project
Response to Additional Information Request, dated October 29, 2021
Dear Mr. Miller:
Piedmont Lithium Carolinas, Inc. (PLCI) would like to thank you for your comments in response to
our North Carolina Mine Permit Application, submitted on August 30, 2021 for the proposed
Carolina Lithium Project (Project). The proposed Project consists of the mine excavation and
corresponding infrastructure, Concentrate Operations, and a Lithium Hydroxide Conversion Plant.
Please see the following responses to your Additional Information Request. Comments are in bold
text and responses are provided in regular text. Two copies of this response are provided, including
an electronic copy.
Additionally, since the submittal of the Mine Permit Application in August 2021, the Gaston County
Unified Development Ordinance (UDO) was updated (approved draft dated 0912912021)' and the
design submitted in this response reflects changes in the UDO such as a revised setback from the
permit boundary, sound wall barrier placement in certain areas, and additional screening berms.
Should you have any questions or require additional information following your review of the
enclosed materials, please contact me at [phone] or pbrindle0r)iedmontlithium.com.
Your ly,
7.W• �Ie
Patrick H. Brindle
Executive Vice President and Chief Development Officer
Piedmont Lithium Carolinas, Inc.
i.1 11.1c,
Page 1 of 10

Attachments:
Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
Appendix A: MSD Sheets
Appendix B: General Heavy Media Circuit Simplified
Appendix C: Water Supply Well Mitigation Plan
Appendix D: Proof of NCG02 Notice of Intent Application Submittal
Appendix E: Blast Impact Study
Appendix F: Item D.7 - Revegetation Plan
Appendix G: Response to DEMLR Mooresville Regional Office
Comments
Appendix H: Two Rivers Utilities Letter to Piedmont Lithium
Appendix I: Technical Memorandum — WWTP Considerations
Appendix J: Groundwater Well Observation Network Figure
Appendix K: Federally and State -Threatened and Endangered Species
Survey
Appendix L: Archaeological Survey of the Carolina Lithium Mine Project
Expansion, Gaston County, North Carolina
Appendix M: Response to Division of Water Resources — Industrial
Permitting Unit Comment #3
Page 2 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
From the "Application for a Mining Permit" form:
1. From item C.3.a of the form:
a. The application lists several chemicals you are requesting to use. Please
supply MSD sheets for the reagents and chemicals listed in the application.
The below table lists the MSD reagents including common name and use. See
Appendix A for the MSD sheets for each reagent PDF bookmarked by a MSD ID
Table 1. Summary of reaaents listed in the mine nermit annlication.
Concentrator and Byproducts Plants
MSD ID
Reagents
Common Name
Use
1
Ferrosilicon
FeSi
Dense Medium Separation (DMS)
2
Fatty Acid - Oleic Acid
FA-2
Spodumene flotation - collector
3
Tallow alkyl amine acetate
Armac T
Mica flotation - collector
4
Hydrofluoric acid (47-48%)
HF
Feldspar flotation - collector
3 and 5
Tallow alkyl amine acetate
and Coco amine acetate mix
Armac T / Armac C
Feldspar flotation - collector
6
Kerosene
Feldspar flotation - promoter
7
Methyl Isobutyl Carbinol
MIBC
Mica flotation - frother
8
F220
Proprietary chemical -
chemically modified natural
polymer Ca, S, C hydrates
Flotation - Dispersant
9
Magnafloc 10
Flocculant
10
Sodium Hydroxide (50%)
Caustic Soda
pH control - mica flotation & high
intensity scrubbing
11
Sodium Carbonate (100%)
Soda Ash
pH control - spodumene flotation
12
Sulfuric acid (98%)
H2SO4
pH control - feldspar flotation
13
Activated Carbon
Water treatment
14
Calcium Hydroxide (20%w/w
Slurry)
Milk of Lime
Water treatment
Chemical Plant
MSD ID
Reagents
Common Name
Use
11
Sodium Carbonate (95%)
Soda Ash
lithium extraction/precipitation from
s odumene
15
Hydrated Lime (100%)
Lime
lithium hydroxide conversion step
16
Hydrochloric Acid (33%)
IX resin regeneration
17
Sodium Hydroxide (98%)
Caustic Soda
pH control
18
Trisodium Phosphate
Lithium phosphate precipitation
19
Sulfuric Acid (> 92%)
Cleaning acid
20
Lewatit MDS TP208
Cation Resin
Ion exchange
21a or
21 b
Antiscalant
Demineralized Water Reverse
Osmosis
22
Sodium Bisulfate
Demineralized Water Reverse
Osmosis
23
DBNPA
Biocide - Evaporative coolers
24
Sodium Molybdate
Corrosion inhibitor- Boiler
25
Sodium Polyphosphate
Inhibitor - Boiler/Demin water
Page 3 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
b. Your application states the there will be a "heavy media separation" circuit
in the Concentration plant. Please explain this circuit, what is the make up
of the heavy media, and how will it be removed from the material being
separated.
Regarding the heavy media circuit, or dense media separation (DMS), Ferrosilicon
(FeSi) is the only reagent used in that part of the plant. The heavy media circuit is
a gravity separation technique using heavy particles such as FeSi to alter and
control the density of water (heavy media) causing lighter particles to float and
heavier particles to sink. Water and magnetic separators are added to control the
density within the heavy media circuit.
A mixture of heavy media and sized spodumene ore will be passed through a
dense media cyclone. The cyclone separates particles according to their specific
gravity. Spodumene concentrate (sinks) will be discharged from the apex (bottom)
of the cyclone, whereas gangue minerals (floats) will discharge from the vortex
(top) of the cyclone.
The heavy media is separated from the sinks and floats and is recovered on drain
and rinse (D&R) screens. On the first section of the D&R screens free draining
heavy media passes through the screen and is returned to the heavy media circuit.
On the second section of the screen the heavy media is washed off ore particles
in the streams to the screen underflow at the rinse sections of the D&R screens
using process water. The resulting dilute media is passed through magnetic
separators to a magnetic concentrate (FeSi) which is then returned to the heavy
media circuit. The effluent from the magnetic separators is recycled as process
water forming a closed circuit.
A process flow diagram of the heavy media circuit is included in Appendix B.
The Concentrator has four (4) such DMS circuits.
There are no other reagents used in the heavy media processing of spodumene.
2. From item C.3.c of the form, the application states there is a water supply well
mitigation plan. Please supply a copy of the well mitigation plan. Note, it is
recommended that you review plans submitted by other permittees in the State.
See Appendix C for a Water Supply Well Mitigation Plan.
3. From item C.3.d of the form, the application states that the applicant will apply for
the correct NPDES permits. Please provide proof that the company has submitted
an application for or has received a NPDES stormwater permit.
A Notice of Intent (NOI) for NCG02 coverage was submitted electronically on 11/12/2021,
with a hard copy followed in the mail. A Pumping Operation and Monitoring (POM) Plan
was submitted with the NCG02 NOI. See Appendix D for proof of NCG02 NOI submittal.
Page 4 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
4. From item C.8 of the form, the applicant states a 6-foot security fence will be erected
around the site. Please explain how the operation will handle trash and vegetated
matter building up where the 6-foot fence crosses streams.
Per the Gaston County Unified Development Ordinance, a 7-foot chain -link security fence
with an additional foot of 3-strand barbed wire will be erected around the site. Fences will
terminate at the top of stream banks and will not be constructed across streams. This will
allow for a wildlife travel corridor along the stream and avoid trash and debris build up.
The perimeter fence will be posted with No Trespassing signs to prevent inadvertent public
access into the site at each stream location.
5. From item CA 1 of the form, the application appears to be mimicking the Z-curve for
blasting. Either state the company will keep all blast vibrations below the Z-curve
or supply compelling reasons to allow the company to exceed the Z-curve. It is
acceptable to make the curve more restrictive. Please supply a plot as to what the
company is recommending.
All blast vibrations will be below the Z-Curve for particle velocity as shown below based
on the frequency of the blast vibration or 2 in/sec whichever is less:
-�
UNSAFE BLASTING REGIONS
U)
(above solid line for drywall) 2.0 ips
1.00
0.75 ips (drywall)
0.5 ips (plaster] '
- - - - - - -
c�
a
a�
a�
E
E 0.10
SAFE BLASTING REGION
0
to prevent hairline cracking
a�
E
(below solid line for drywall)
E
X
ns
0.01
1
10 100
Blast Vibration Frequency (Hz)
Page 5 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
6. From item CA 1 of the form, please submit a third -party Projected Impact of Blasting
on Adjacent Structures report.
A third -party Blast Impact Study is provided in Appendix E.
7. From item CA 1 of the form, please explain any adjustment the company might make
to their blasting on cloudy days.
PLCI will check with the Lincolnton-Lincoln Regional Airport or Charlotte Douglas
International Airport when overcast conditions are present to make sure an inversion is
not in progress.
8. From item D.7 of the form, please state what sort of mulch is being applied. If the
company is planning to apply different types of mulch, such as wheat straw versus
wood chip mulch, each type of mulch would require different lime and fertilizer
rates.
Please see Appendix F.
9. From item D.7 of the form, the plan was not signed by an approved signature
authority. Please supply a plan signed by an approved signature authority.
Please see Appendix F.
For information requested by agencies, Departments or Division, it is recommended that
the company consult with the individual source associated with each item:
1. Please address the concerns of the Department of Environment Quality - Division
of Energy, Mineral, and Land Resources - Mooresville Regional Office, as listed in
attachment Item I.
See Appendix G.
2. Please address the concerns of the Department of Environment Quality - Division
of Water Resource - NPDES Industrial Permitting:
a. Section C.3.d, of the application indicates that wastewater from the chemical
operation will be discharged to a Publicly Owned Treatment Works with
pretreatment. Please supply the name of the Publicly Owned Treatment
Works, and a copy of the agreement.
Please see Appendix H for a letter provided to PLCI by Two Rivers Utilities. This
letter states that the proposed project is located within the service area of their
Long Creek Wastewater Treatment Plant (WWTP) facility which is an advanced
biological nutrient removal treatment facility with an existing pretreatment program.
Page 6 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
Based on the Technical Memorandum — Wastewater Treatment Plant
Considerations (Appendix 1), the projected peak discharge rate from the PLCI's
facility is 0.22 million gallons per day (mgd). The Two Rivers Utilities letter states
that the Long Creek WWTP has an available capacity of 6.4 mgd to serve the
proposed project. Two Rivers Utilities would also require PLCI to submit a
wastewater discharge permit and further evaluation of the effluent to determine the
level of pretreatment necessary.
Two Rivers Utilities may require PLCI to participate in sewer system improvements
to accommodate the additional flows from the proposed project once a route to the
site has been determined.
b. Please supply a chemical analysis of the discharge in item 2(a).
Please see the answer above to 2a. PLCI has requested the letter provided by
Two Rivers Utilities as good faith evidence that ongoing coordination with the local
sewer service provider is occurring to discharge their process wastewater effluent
to a POTW with pretreatment.
3. Please address the concerns of the Department of Environment Quality - Division
of Water Resource -Groundwater Management Branch, as listed in attachment Item
II.
Per the Groundwater Management Branch comments (attachment Item II), and the
request in #2 above (page 4), see Appendix C for a Water Supply Well Mitigation Plan.
Per review of the groundwater monitoring well network submitted on the Overall Site Plan
(Appendix A of the Mine Permit application) and the predicted drawdown contours
presented in the Groundwater Model (Appendix H of the Mine Permit application), and in
addition to the 17 observation wells PLCI has already committed to installing, PLCI offers
to add the following observation wells (see Appendix J for an updated Groundwater
Observation Well Network Figure):
• 3 additional wells between OB-1 and OB-2
• 2 additional wells between OB-3 and OB-4
• 1 additional well between OB-4 and OB-5
• 1 additional well between OB-10 and OB-11
• 1 additional well between OB-13 and OB-1
• 2 additional wells on the northwest side of the West Pit
PLCI respectfully declines to add additional groundwater monitoring wells between OB-15
and OB-17 and between OB-17 and OB-18 as the groundwater model does not indicate
measurable drawdown in these areas and PLCI believes the currently proposed
monitoring network is sufficient. Should conditions in these areas change once dewatering
commences, PLCI will revisit this request.
Page 7 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
PLCI also commits to monitoring groundwater levels beginning no less than 60 days prior
to dewatering activities. Please note that PLCI has already conducted 17 groundwater
level gauging events from July 2018 to February 2020 as presented in Appendix F of the
Mine Permit application. These measurements are representative of baseline
groundwater level conditions and support additional measurements collected prior to and
during dewatering activities.
4. Please address the concerns of the Department of Environment Quality - Division
of Air Quality - Mooresville Regional Office:
a. Please supply proof that the site has received an Air Permit.
A pre -consultation meeting with NC Department of Air Quality — Mooresville
Regional Office is scheduled to be held on December 15, 2021. Based on
alignment from the pre -consultation meeting between PLCI and DAQ, PLCI plans
to submit an Air Quality permit application no later than January 14, 2022.
b. In the application, Appendix D, page 2, the plan presented is to open burn
waste vegetated material. DAQ would prefer that the company seek other
ways to dispose this material in hot dry summer periods. Please supply a
plan to address this concern. Please remember that if the company decides
to mulch this material and use it for erosion control, your reclamation plan
must reflect this.
Please see Appendix G, Attachment 3.1 which now includes the clearing and
grubbing material disposal plan. A burning permit would be obtained from the
County Fire Marshall prior to burning; if burning is not allowed due to dry periods
or air quality, materials would be disposed of in a demolition landfill.
5. North Carolina Wildlife Resources Commission noted that in the application you
stated that "HDR conducted surveys for federally protected species, and none were
observed within the proposed mine site." Please supply a copy of this study.
Please see Appendix K. No federally protected species were observed on the site.
6. Please comply with the State Historic Preservation Office request, see attached item
III.
Please see Appendix L. At the request of HDR, on behalf of PLCI, TRC conducted an
intensive archaeological survey on a 963-acre area of potential effect (APE) in 2018 and
2019 for the original Carolina Lithium Project area. The North Carolina State Historic
Preservation Office (NCSHPO) concluded that no known archaeological sites listed in or
eligible for listing in the National Register of Historic Places (NRHP) would be adversely
impacted by the original project area.
Page 8 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
In 2021, TRC conducted a Phase I cultural resources survey of a 929-acre expansion to
the original 963-acre project area (Appendix L). The recent 929-acre cultural resources
survey investigated the expanded mine boundary as well as 228 acres outside the mine
boundary. TRC conducted this survey under standards set by the NCSHPO, and in
compliance with Section 106 of the National Historic Preservation Act (NHPA), 36 CFR
800.
TRC recorded nineteen field sites as a result of the 2021 expanded mine boundary APE.
Thirteen of these are historic in nature, two are prehistoric isolated finds, and four are
cemeteries. TRC recommends that the historic and prehistoric sites are not eligible for
listing on the NRHP and no additional archaeological studies are needed for those sites.
The four historic cemeteries have not been assessed for NRHP eligibility and will need to
be avoided with a minimum 25-foot buffer surrounding each. Two of these cemeteries are
within the Mine Permit boundary in the Lithium Hydroxide Conversion Plant area — PLCI
has avoided these with a larger 50-foot buffer than what is recommended. The remaining
two cemeteries are outside the Mine Permit boundary and not subject to the mine permit
review.
NCSHPO did not require/request an architectural survey in 2018 and 2019 for the original
APE. There are no currently listed properties listed on the NRHP within or directly adjacent
to the expanded APE. In the absence of a federal nexus requirement for Mine Permit
review, an architectural survey is not required per NCSHPO.
Page 9 of 10

Piedmont Lithium Carolinas, Inc. I Carolina Lithium Project
Response to Mine Permit Additional Information Request
December 15, 2021
Lastly, PLCI would like to offer a response to the Division of Water Resources —
Industrial Permitting Unit comment letter (dated 11/1212021) (Appendix M). This comment
letter was supplied via email by your office to PLCI on 11/16/2021.
1. Chemical Processing Wastewater
Please see the response to 2a and 2b (pages 6 and 7) and Appendix H and I.
2. Individual NPDES Industrial Permit Coverage and Chemical Analysis
Please see the response to 2a and 2b (pages 6 and 7) and Appendix H and I. PLCI's
intent is to pretreat and discharge process waters (including boiler blowdown, scrubber
waste, and cooling water) to a POTW.
PLCI is respectfully requesting the letter provided by Two Rivers Utilities as good faith
evidence that ongoing coordination with the local sewer service provider is occurring
to discharge their process wastewater effluent to a POTW with pretreatment.
3. Waste Rock and Tailings Leaching
Please see Appendix M for the response to Comment #3.
Page 10 of 10