TM_PiedmontLithium_AquiferTest_20190125

J 17 OlOA!
Technical
Memorandum
Aquifer Test
Piedmont Lithium
Gaston County, North Carolina
January 25, 2019

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Contents
Contents
Contents.........................................................................................................................................
i
Introduction...................................................................................................................................1
Methods........................................................................................................................................1
PumpingWell............................................................................................................................1
Results..........................................................................................................................................5
Conclusions..................................................................................................................................7
Figures
Figure1 - Site Feature Map..........................................................................................................2
Figure2 - Pumping well drawdown...............................................................................................4
Figure 3 - Drawdown in observation wells....................................................................................6
Tables
Table 1 - Pumping well and observation well construction details and locations relative to the
pumpingwell.................................................................................................................................3
Table 2 - Step test and constant rate pump test methods............................................................4
Table 3 - Results of the analyses..................................................................................................6
Appendices
Appendix A - Aquifer Test Analyses

Piedmont Lithium I Technical Memorandum - Aquifer Test �J�
Contents
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Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Introduction
Introduction
HDR Engineering, Inc. of the Carolinas (HDR) performed an aquifer test at the planned
Piedmont Lithium, Inc. (PLI) mine site (site) between October 8 and 10, 2018. Pumping well
PW-1 was pumped and observation wells OW-1 S, OW-1 D, OW-2S, OW-21D, and MW-5 were
monitored to evaluate hydrogeologic properties of the unconfined regolith and fractured bedrock
rock aquifers.
Methods
Pumping Well
The aquifer test was completed by pumping from PW-1, a well located in the northern part of the
project area on PLI-accessible land (Figure 1). Well PW-1 is a 6-inch (in) diameter, 500 foot
deep open borehole, with the top 105 feet completed with 6-in diameter schedule 40 PVC within
the unconsolidated regolith. Geologic Exploration, Inc. installed a Berkeley 4-in submersible 5-
horsepower (HP) pump at 318 feet below the top of casing and operated the pump test while
HDR monitored water levels and directed the pumping rate changes.
An In -Situ vented transducer (Level TROLL 700) was suspended in each of the pumping and
observation wells in Table 1. Water level measurements were recorded at 1-minute intervals for
several weeks prior to the test, during the test, and during aquifer recovery.

0 Pumping Well
Observation Well
Study Area
Stream
Topographic Contour
CA -
SITE FEATURE MAP
PIEDMONT JANUARY 2019
FIGURE 1
PATH: \\CLTSMAIN\GIS_DATA\GIS\PROJECTSM135_PIEDMONTLITHIUM100896a0_PIEDMONTLITHIUM7.2_WORK _IN_PROGRESS\MAP_DOGS\MMHYDROGEO\PUMPINGTEST_HOURE A= - USER:CMARCHIN - DATE:112512019 AQUIFER TEST ANALYSIS

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Methods
Table 1 - Pumping well and observation well construction details and locations relative to the pumping well
Distance Well Total
Well ID to PW-1 Diameter Depth Screened unit or open borehole
(feet) (feet bgs)
PW-1 0 6-in 500 Cherryville Granite
OW-1S 102.37 2-in 60 Unconsolidated regolith
OW-1 D 110.33 6-in 302 Cherryville Granite
OW-2S 217.31 2-in 30 Unconsolidated regolith
OW-21D 207.96 6-in 300 Cherryville Granite
MW-5 547.22 6-in 152 Cherryville Granite
The aquifer test was planned as a step-drawdown test followed by a 72-hour constant rate
pumping test. A step-drawdown test is a single -well pumping test designed to investigate the
performance of a pumping well under controlled variable discharge conditions. In a step-
drawdown test, the discharge rate in the pumping well is increased from an initially low constant
rate through a sequence of pumping intervals (steps) of progressively higher constant rates.
Each step is typically of approximate equal duration. The step drawdown test was planned with
steps of pumping intended at 35, 55, 80, and 100 gallons per minute. The purpose of the step
drawdown test at PLI was to evaluate the maximum pumping potential of the fractured rock.
Table 2 provides the sequence of pumping and recovery completed and Figure 2 displays the
drawdown and recovery curve in the pumping well PW-1. The pump and motor utilized did not
have the horsepower to pump the 80 gpm rate, and investigation of the pump curve for the
pump provided by Geologic Exploration, Inc. indicated that there was a higher horsepower
motor for the same pump that would be more likely to achieve the higher pumping rates desired.
The new pump was ordered and intended to be installed the morning of October 10, 2018;
however, rainfall made the road unsuitable for a pump rig to access the well. Therefore, a
constant rate test was still completed at the highest rate possible for the installed pump. The
length of the constant rate pump test was shortened to 30 hours for two reasons, 1) Hurricane
Michael was approaching and the rainfall was predicted to be significant starting on October 11,
2018, which would skew the drawdown effects making analysis unfeasible; and 2) the
drawdown had stabilized in the pumping well (Figure 2).

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Methods
Table 2 - Step test and constant rate pump test methods
Adjustment
Rate
(gpm)
Date and
Time
Duration
(min from start)
Notes
Step Test Start
35
10/8/2018
0
NA
15:38
Step Test Rate Change
55
10/8/2018
121
NA
17:39
Step Test Rate Change
80
10/8/2018
300
Pump could not sustain 80 gpm
20:38
so began troubleshooting
Step Test End (Recovery
0
10/8/2018
344
NA
Start)
21:21
Rate held at 57 gpm for
10/9/2018
approximately 4 hours, then
Constant Rate Test Start
45-57
8:12
995
slowly decreased as the water
level decreased and stabilized
for last 14 hours at 45 gpm
End test
0
10/10/2018
2783
30 hours
14:00
PW-1 Pumping Well Drawdown
250
200
c
150
3
0
100
.Ik
50
0
OOtiA
°`ti
ti
'O-O\Y
Figure 2 - Pumping well drawdown
tio� tio19 ,�olti �olti 1olti �o`titi
Date
4

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Results
Results
The constant rate pumping test was completed over 30 hours of pumping. The pumping rate
started at 57 gpm and was maintained for several hours before the water level dropped such
that the pump could not maintain the rate and slowly declined. During the last 14 hours of the
test, the pump maintained a rate of 45 gpm. Figure 3 displays the drawdown recorded by
transducers in observation wells. In wells approximately 100 feet from the pumping well,
approximately 1.15 feet of drawdown was recorded in the deep well and 0.87 feet of drawdown
in the shallow well. In wells approximately 200 feet from the pumping well, approximately 0.70
feet of drawdown was recorded in the deep well and 0.17 feet of drawdown in the shallow well.
Well MW-5 had a maximum drawdown of approximately 0.46 feet and is located approximately
550 feet away from PW-1. Other monitoring wells on the property were also monitored (MW-1,
MW-2, MW-3, and MW-4) and no drawdown was observed. These four monitoring wells are
between 1,000 and 4,500 feet away from the pumping well.
Aqtesolv was used to analyze the drawdown data. Specifically, HDR applied the Theis (1935)
and Neuman (1974) method of analysis for unconfined aquifers. Aquifer model solutions
assume anisotropy, even though all the wells are partially penetrating in the formation. Table 3
summarizes the transmissivity, calculated hydraulic conductivity, storativity, and specific yield
and Appendix A includes the curve fit graphs and model results. The aquifer transmissivity was
calculated to range between 0.014 and 0.034 feet squared per second (ft2/s). Using the
saturated thickness of the pumping well as the assumed saturated thickness of the aquifer
(494.8 feet), the aquifer hydraulic conductivity ranged between 0.040 to 0.098 feet per day (ft/d).
The storativity and transmissivity values are very similar between the shallow and deep
observation wells. The results indicate that the aquifer has high hydraulic conductivity (0.040 to
0.098 ft/d) for fractured crystalline rock (Heath, 1983, Domenico and Schwartz, 1990).
Shallow observation wells (OW-1 S and OW-2S) were completed in the unconsolidated regolith
above the bedrock. Deep observation wells were completed in the bedrock (OW-1 D, OW-2D,
and MW-5). The following data indicate that there is high horizontal and vertical connectivity
between the fractured rock and the unconsolidated regolith that lies above:
• Very similar storativity and transmissivity values between the shallow and deep
observation wells;
• Drawdown response in deeper wells (delayed yield) indicates recharge from overlying
regolith;
• Water levels in the shallow and deep observation wells are very similar (approximately
0.5 foot difference in OW-1 S and OW-1 D and approximately 1 foot difference in OW-2S
and OW-2D);
• Water levels in the shallow and deep observation wells respond to pumping and
recovery and rainfall events similarly (Figure 3);
• Recharge rates in bedrock wells are rapid and similar to rates observed in paired regolith
wells;
• PLI and HDR boring logs do not indicate any confining unit between the unconsolidated
material and the fractured rock.

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Results
PLI Aquifer Test
1.5
Constant , / Pump Stop
Rate Test r
1 S art /
Recover
0.5
/ Recovery
9�s -OW-IS
N 00 'zT O LD N 00 'zT O LD fV 00 V O LD N LD N 00 'q O lD N 00 ':T O-OW-ID
N Ln I, O M Ln 00 O M LD 00 N M lD a) c-i 0) :T n Ol N Ln I, O " Ln 00
O N LD 0) c-i M Ln 00 O N �T n 0) rI M to 00 O N O1 N �7r to 00 N M Ln I,
-a c-i t-I N N N N N" N M M M M v v M M Ln Ln LD LD LD LD —OW_2S
M0.5 \ OW-21D
Step
Test
M W-5
1 Recharge from
hurricane rainfall
(3.5") _y�+
-1.5
-2
Time (min)
Figure 3 - Drawdown in observation wells
Table 3 - Results of the analyses
Solution
OW -IS
OW-1D
OW-2S
OW-2113
MW-5
Transmissivity (ft2/s)
0.032
0.034
0.027
0.020
0.014
Theis
Hydraulic Conductivity
0.092
0.098
0.078
0.058
0.040
Unconfined
(ft/d)*
Storativity
0.067
0.054
0.089
0.021
0.007
Transmissivity (ft2/s)
0.032
0.034
0.024
0.019
0.014
Neuman
Hydraulic Conductivity
0.092
0.098
0.069
0.055
0.040
(mod)*
Unconfined
Storativity
0.067
0.053
0.076
0.019
0.0073
Specific Yield
0.1
0.1
0.3
0.3
0.3
"assuming a saturated thickness of 494.8 feet (saturated thickness of PW-1)
6

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Conclusions
Conclusions
The results of the aquifer test provide a baseline understanding of hydrogeologic properties
beneath the project site and show connection between the regolith and fractured bedrock
geologic units. Further, drawdown was observed in shallow observation wells, as far as 200 feet
from the pumping well, and in deep observation wells, as far as 550 feet from the pumping well.
Based on these data, HDR recommends completion of additional aquifer testing within the PLI
site to evaluate spatial variability in hydrogeologic properties and to assess potential effects of
pumping on nearby water supply wells, wetlands, and streams.

Piedmont Lithium I Technical Memorandum - Aquifer Test �1�
Conclusions J
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Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Appendix A - Aquifer Test Analyses
Appendix A - Aquifer Test
Analyses

Piedmont Lithium I Technical Memorandum - Aquifer Test ���
Appendix A - Aquifer Test Analyses
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0
0.1
0.01
0.001 L
1.
10. 100.
Time (min)
WELL TEST ANALYSIS
1000. 1.0E+4
Data Set: C:\Users\mreeves\Documents\Piedmont Lithium\Aquifer test data\Analysis\OW1 D.aqt
Date: 12/14/18 Time: 09:36:35
Company: HDR
Test Well: PW1
Saturated Thickness: 494.8 ft
PROJECT INFORMATION
AQUIFER DATA
\A/P:I I r)ATA
Well Name
X ft
Y ft
PW-1
0
0
Aquifer Model: Unconfined
T = 0.03435 ft2/sec
Sy = 0.1
Observation Wells
Well Name
X ft
Y ft
° OW-1 D
110.33
0
Cnl I ITInN
Solution Method: Neuman
S = 0.05314
R = 1.021E-5

0
0.1
0.01
0.001 L
1.
0
10. 100.
Time (min)
WELL TEST ANALYSIS
1000. 1.0E+4
Data Set: C:\Users\mreeves\Documents\Piedmont Lithium\Aquifer test data\Analysis\OW1S.agt
Date: 12/14/18 Time: 09:33:04
Company: HDR
Test Well: PW1
Saturated Thickness: 494.8 ft
PROJECT INFORMATION
AQUIFER DATA
\A/P:I I r)ATA
Well Name
X ft
Y ft
PW-1
0
0
Aquifer Model: Unconfined
T = 0.03213 ft2/sec
Sy = 0.1
Observation Wells
Well Name
X ft
Y ft
° OW-1 S
102.37
0
Cnl I ITInN
Solution Method: Neuman
S = 0.06671
R = 1.021E-5

z
0.1
0.01
0.001
1 OE 4
1. 10. 100. 1000. 1.0E+4
Time (min)
WELL TEST ANALYSIS
Data Set: C:\Users\mreeves\Documents\Piedmont Lithium\Aquifer test data\Analysis\OW2D.agt
Date: 12/14/18 Time: 09:37:59
PROJECT INFORMATION
Company: HDR
Test Well: PW1
Pumnina Wells
WELL DATA
Well Name
X ft
Y ft
PW-1
0
0
Observation Wells
Well Name
X ft
Y ft
° OW-21D
207.96
0
SOLUTION
Aquifer Model: Unconfined Solution Method: Theis
T = 0.02006 ft2/sec S = 0.02054
Kz/Kr = 1. b = 494.8 ft

z
a�
a)
U
(6
Q
Cn
w
0.1
0.01
0.001
1 OE 4
❑
a
a ❑
❑
❑
❑
❑
1. 10. 100. 1000. 1.0E+4
Time (min)
WELL TEST ANALYSIS
Data Set: C:\Users\mreeves\Documents\Piedmont Lithium\Aquifer test data\Analysis\OW2S.agt
Date: 12/14/18 Time: 09:37:25
PROJECT INFORMATION
Company: HDR
Test Well: PW1
Saturated Thickness: 494.8 ft
AQUIFER DATA
WELL DATA
Well Name
X ft
Y ft
PW-1
0
0
Aquifer Model: Unconfined
T = 0.02449 ft2/sec
Sy = 0.3
Observation Wells
Well Name
X ft
Y ft
❑ OW-2S
217.31
0
SOLUTION
Solution Method: Neuman
S = 0.07642
R = 0.03063

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