21050_South Saunders St_GeophyRpt_20220614

Technical Report
Geophysical Evaluation
Park City South Phases 2 & 3
927 S. Saunders Street
Raleigh, North Carolina
91
A 1.
Y'Vfl ,
Prepared For:
Hart & Hickman, PC
Prepared By:
Geo Solutions Limited, Inc.
June 14, 2022

C�eO L�l,
P.O. Box 293
Conway, NC 27820
[phone]
June 14, 2022
Justin Ballard, PG
Hart & Hickman, PC
3921 Sunset Ridge Rd, Ste 301
Raleigh, NC 27607
Re: Geophysical Evaluation — Park City South Phases 3 & 4 — 927 S. Saunders Street
Raleigh, NC
Dear Mr. Ballard:
Geo Solutions Limited, Inc. (Geo Solutions) is pleased to submit this report to Hart &
Hickman, PC (Hart & Hickman) of a geophysical evaluation of a site that is planned for
development at 927 S. Saunders Street in Raleigh, North Carolina.
Background
Hart & Hickman is completing an environmental site assessment of a planned development
site known as Park City South located on S. Saunders Street in Raleigh, NC. Construction
in Phase 1 of the development is currently underway. Large amounts of buried debris were
encountered during the grading of Phase 1. The majority of the debris was composed of
concrete slabs, rebar, scrap metal, and other construction debris. Geo Solutions was
contracted to complete a geophysical evaluation of the Phase 1 area in March 2022 to
delineate the buried debris. Phases 2 and 3 of the Park City South development lies South
of the Phase 1 area. Phase 2 and 3 have not been cleared and grubbed and is covered with
dense vegetation. Hart & Hickman contracted Geo Solutions to complete a geophysical
evaluation of this area to detected potential buried debris following the same technical
approach as used in the Phase 1 area.

The site is approximately 4.0-acres in size however all of the site is not accessible due to
thick vegetation. Figure 1 below and at the rear of this report is a site map with the
geophysical evaluation boundary delineated in yellow.
LEGEND
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Figure 1. Site map with the geophysical evaluation boundary delineated in yellow and inaccessible
areas delineated in blue.
Technical Approach
Geo Solutions completed the evaluation utilizing three geophysical methods to investigate
the property at 927 South Saunders Street in Raleigh, NC.

Multifrequency Electromagnetic (EM) Evaluation
A high resolution electromagnetic (EM) evaluation was completed using a Geophex Model
GEM-2 multifrequency electromagnetic profiler which collects at a rate of 30 times per
second. The EM data was collected on a hand-held data logger that communicated with the
GEM-2 unit via Bluetooth. The GEM-2 was connected to a Hemisphere Model A-325 GPS
unit which is augmented by the Wide Area Augmentation System (WAAS) and is capable
of submeter accuracy. The EM profiler was hand carried using a shoulder strap with the
GPS mounted on a backpack through accessible areas of the site. Dense vegetation was
present throughout most of the site. Some areas were inaccessible. The EM profile spacing
was variable but overall moderate coverage of the site was achieved (Figure 2). The EM
method is useful at evaluating the shallow subsurface for both metallic and non-metallic
conductive materials such as buried construction debris, tires, scrap metal, and underground
storage tanks (USTs) which may be related to former land use. Once data collection was
complete the EM data were transferred to a laptop computer. The data was then used to
create a contour map of the EM results using Surfer 18 so that the draft results could be
reviewed in the field.
Magnetometry Evaluation
Geo Solutions completed a magnetometry evaluation of the site. Magnetometry evaluations
also known as total field magnetic evaluations area useful at detected iron or nickel bearing
materials. The purpose of the total field magnetic evaluation is to further characterize the
composition of the buried debris by providing a means to differentiate areas of metallic
(steel) debris compared to areas of non-metallic conductive materials. Geo Solutions
utilized a GEM Systems GSMP-35 potassium total field magnetometer which has an
operating sensitivity of 0.0003 nT and a data collection rate of 20 readings per second. The
GSMP-35 magnetometer was mounted on a backpack and walked over the accessible areas
of the site. The magnetometer is larger and less maneuverable than the GEM-2 EM
profiler. The magnetic profile spacing was variable with slightly less coverage than the
EM data. Once data collection was complete the magnetic data was transferred to a

laptop computer using the system software. The data was then used to create a contour map
of the magnetic results using Surfer 18 so that the draft results could be reviewed in the
field.
Ground -penetrating Radar (GPR) Evaluation
Geo Solutions completed a limited ground -penetrating radar (GPR) evaluation of
accessible areas of the site. The objective of the GPR evaluation was to image areas of
detected debris identified during the EM and magnetic evaluations. Geo Solutions
completed the GPR evaluation using a GSSI SIR 4000 connected to a 400 MHz antenna.
The 400 MHz antenna was mounted on a three -wheel cart and pushed through areas of
suspected debris. In order to acquire high quality subsurface images with GPR the ground
surface needs to be relatively smooth. Here, the ground surface was very irregular due to
logs, stumps, vines, and roots in the area of investigation.
Results
Multifrequency Electromagnetic (EM) Evaluation
Once adequate coverage was achieved, the EM field data were post -processed to produce
a comma separated variable (CSV) file that was then transferred to a laptop computer.
These data were then processed using software developed by Geophex to calculate the
apparent conductivity and in -phase values for each EM frequency collected (1,47011z, 4,110
Hz, 9,810 Hz, 32,190 Hz, 60,000 Hz, and 90,030 Hz). Typically, the in -phase data
(sometimes referred to as the metal detection mode) is more representative of surficial and
buried metallic materials whereas the apparent conductivity is more representative of non-
metallic conductive materials. The apparent conductivity response can also be elevated in
the presence of large metal features. By evaluating both the in -phase and apparent

conductivity responses, the horizontal extents of conductive and metallic materials can be
characterized. All the frequencies were evaluated and the 9,810 Hz data was chosen to
create figures for this report as it provided the best contrast to background site conditions.
Shown on Figure 3 and Figure 4 are the EM in -phase (metal detection) and apparent
conductivity results maps respectively with explanations for the anomalous conditions
observed in the EM data. Here, anomalous conditions are shown as orange to red andblue
hues where the background site conditions are shown as light yellow and green hues. Two
small to moderate areas of suspected buried debris were detected in both the in -phase
(metal detection) and apparent conductivity data. These areas have been delineated on
Figures 3 and 4. Thirty (30) points have been assigned to delineate these boundaries.
Approximate coordinates of these boundary points can be found in Table 1. Other less
significant areas of suspected buried metal and scattered debris were detected as well as
surface features.
Magnetometry Evaluation
A map illustrating the results of the magnetometry evaluation is shown on Figure 5. Here,
the total field values have been adjusted by subtracting 49,200 nT from each data point for
easier mapping. The orange, red, blue, and purple hues are areas of suspected buried iron
bearing materials (steel) such a rebar and scrap metal whereas the faint yellow and green
hues are indicative of background site conditions. A similar pattern as noticed in the EM
data can be observed in the total field magnetic data which would suggest metallic materials
are present throughout the areas of buried debris.
Ground Penetrating Radar (GPR) Evaluation
The limited GPR evaluation was completed over areas suspected of buried debris based on
the EM and magnetic data. Access for the GPR evaluation was poor due to the thick
vegetation, logs, and roots. Several profiles were collected over the two areas of suspected
debris delineated on Figures 3 and 4 where shallow buried materials were confirmed.
Shallow buried sheet metal was detected and visually observed at the southernmost EM
anomaly. GPR images were not of high enough quality to include in this report.

Conclusions
• Geo Solutions completed a detailed EM evaluation, magnetometry evaluation, and
limited GPR evaluation of the Phase 2 and 3 areas of the City Park South
development site located at 927 S. Saunders Street Raleigh, North Carolina.
• The entire site was covered in vegetation which limited or prevented access is
some areas.
• Two areas of suspected buried debris were detected during the geophysical
evaluation.
• Other less significant areas of debris were also detected.
• Of the areas covered during the geophysical evaluation it is our opinion that
Phases 2 and 3 have less significant areas of buried debris than the active
construction site in Phase 1.
• We recommend test pits be completed in the west -central portions of the site (see
Figures 3-5) to confirm the presence of debris as well assess the composition and
thickness of the materials.
• Following the completion of the recommended test pits, an additional geophysical
evaluation of the site may be warranted once the vegetation has been removed and
the entire site is accessible.

Limitations
The detection of subsurface objects is dependent upon parameters that include size,
physical composition, and depth of burial. The combination of these parameters may
produce a response that is below the detection threshold for a given geophysical method.
The geophysical methods used at this site require access overtop the target. Some areas of
the site where not accessible due to thick vegetation. Therefore, it is possible that all the
buried debris and subsurface structures such as USTs were not detected during the
geophysical evaluation.
Please don't hesitate to call if you have any questions concerning this report. We appreciate
the opportunity to have worked with you on this project.
Very truly yours,
GEO SOLUTIONS LIMITED, INC.
John DeLoatch, PG
Project Manager

Table 1. List
of Approximate Coordinates of the Suspected Buried Debris Boundaries
Station
Easting NC STATE PLANE (NAD 83) ft
Northing NC STATE PLANE (NAD 83) ft
1
2104198.21
734108.01
2
2104192.43
734133.32
3
2104191.15
734163.58
4
2104201.67
734184.78
5
2104225.89
734198.77
6
2104242.36
734203.47
7
2104251.57
734222.81
8
2104270.72
734235.01
91
2104281.38
734202.04
10
2104290.46
734184.22
11
2104282.88
734152.25
12
2104269.84
734130.48
13
2104243.141
734118.43
14
2104232.721
734101.63
151
2104216.261
734097.56
16
2104404.65
734114.50
17
2104402.19
734136.62
18
2104386.27
734153.21
19
2104363.62
734153.68
201
2104345.38
734142.43
21
2104335.22
734156.58
22
2104335.63
734176.91
23
2104352.05
734184.12
24
2104380.53
734185.28
25
2104405.22
734170.84
26
2104428.89
734163.96
27
2104447.34
734157.19
28
2104439.871
734132.37
29
2104433.731
734116.23
301
2104422.441
734104.26

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LEGEND
Indicates Location of
EM Data Point
Geotechnical Boring
l oc:alion
Map Scale (#t)
0 8.5 170
1" = 85'
Figure Geophysical Evaluation
2 EM Profile Lmation Map
Park City South - Phases 2 &
927 Sarah Saunders Street
Raleigh. North Carolina
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ljo
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Metal s
3
Suspected Minor Amcunt�,
of Scattered Debris
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uspecetad Buried
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of Scattered Debris
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Suspected Shallow
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dIP" Suspected Surface &
Possible Buried Debris
rt.,Interferen" from
Metal Fence
Suspected Surface &
Buried Debris
Metal Debris �
bow
f
LEGEND
10000
3700
3300
2900
7,100
2100
11100
CL
1300
9110
M
500
u=
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1 110
-300
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roll
0
-1100
0
1,100
-1900
TWO
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31 (11)
-3 500
GeotechnicaI Baring
Location
Map Scale (ft)
s
0 35 170
k x -
1"=85'
�.
Figure Geophysical Evaluation
EM hti-phase INletaI Derertion)
Results Map
.�
Park City+ South - Phases 2 & 'J
927 15auth Saunders Street
_
RaJeigh. NorRh Carolina
Crs lifd

0 lq . -
1dSurface ;
Metal s
,k
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Suspected Mirror Ameun "
of Scattered Debris
1 5 •.
it N,
i 4
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ebris
e
y
5
L
V
0
0
Suspected Shallo
Metal Debris
)ected Minor Amounts
of Scattered Debris
rr
r � f
r k
Suspected Surface &
Possible Buried Debris
Fe
,ntererence from
Metal Fence
Suspected Surface
Buried Debris
0
1�
'THY y5 I.
LEGEND
E
1000
185
165
145
125
105
85
5.5
45
£5
5
-15
-3 5
-.55
-7 5
-9 5
-115
-13 5
-155
-17 5
-19 5
Cjeat rsc:hnical 11oririq
Location
Map Scale (ft)
Nor-
0 85 170
1., 8,},
Figure Geophysical Evaluation
4 EM Apparent Con[luctivitw
Results Map
Park City South - Phase=
927 South Saunders Street
Raleigh. North Ca rohna
Crs UIL

w �
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} Suspected Minor
Amounts of Scattered DArk
r _
rDuspecte; Buried
ebris 40
i
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40
r w>
Concrete Wall
itl, Possible Steel
LEGEND
Reinforcement
LO
O
10000
12
925
t
5'
f
825
=
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g 725
All.r
,
525
°
S2S
425
in 325
225
T
125
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r
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t -175
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1-975
LL-575
-675
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-87 5
,A
Geotechnical Boring
spected Surface
Buried Debris ti
Map Scale (ft)
0 85 DO
1" = 85'
Figure OwPhOcalEwaluation
5 Magnetic Resuits Map
Park City South - Phases 2 &
927 Sairth Satinders Street
RaJeigFh. North Carolina
Ces SEPE LhL