2018-07-02 Duke Energy Mayo Basin Investigation Pumping Work Plan

16V
synTerra
ASH BASIN PUMPING TEST
WORK PLAN
AT
MAYO STEAM ELECTRIC PLANT
10660 BOSTON ROAD
ROXBORO, NORTH CAROLINA 27574
PREPARED FOR
DUKE ENERGY PROGRESS, LLC
DUKE
EIDE RGYo
PROGRESS
estop er H. Bruce, NC LG 2246
Sr. Geologist
Ier A. Wylie, N LG 1425
Pro'p,d Manager

Ash Basin Pumping Test Work Plan July 2, 2018
Mayo Steam Electric Plant SynTerra
TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION.........................................................................................................1-1
2.0 SITE CONCEPTUAL MODEL...................................................................................2-1
2.1 Site Geology and Hydrogeology............................................................................ 2-1
2.1.1 Site Geology......................................................................................................... 2-1
2.1.2 Site Hydrogeology.............................................................................................. 2-2
3.0 WELL INSTALLATION.............................................................................................. 3-1
3.1
Installation of Pumping and Observation Wells ..................................................
3-1
3.1.1
Ash Pumping Well Installation.........................................................................
3-1
3.1.2
Ash Observation Well Installation...................................................................
3-2
3.2
Well Development....................................................................................................
3-2
4.0
AQUIFER PUMP TEST DATA NEEDS....................................................................4-1
5.0
AQUIFER PUMPING TEST.......................................................................................5-1
5.1
Static Water Level Collection..................................................................................
5-1
5.2
Pumping System Installation..................................................................................
5-1
5.3
Step -Drawdown Test................................................................................................5-1
5.4
Step Test Recovery....................................................................................................5-2
5.5
Constant -Rate Pumping Test..................................................................................
5-2
6.0
WATER -QUALITY MEASUREMENTS AND SAMPLING .................................
6-1
7.0
ANALYSIS OF WATER -LEVEL DATA...................................................................7-1
7.1
Baseline Analysis.......................................................................................................
7-1
7.2
Step Test Analysis.....................................................................................................
7-1
7.3
Constant Discharge Rate Test Analysis.................................................................
7-1
8.0
REFERENCES................................................................................................................
8-1
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LIST OF FIGURES
Figure 1-1 Site Location Map
Figure 1-2 Mayo Plant Vicinity Map
Figure 3-1 Proposed Locations for Ash Basin Pumping Test
Figure 5-1 Typical Flow Meter Configuration
Figure 5-2 Typical Step Test Drawdown Curve
LIST OF TABLES
Table 3-1 Proposed Well Construction Details
Table 5-1 Proposed Wells to be Monitored During Ash Basin Pumping Test
LIST OF APPENDICES
Appendix A Boring Logs for ABMW-2 and ABMW-3 Well Clusters
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1.0 INTRODUCTION
Duke Energy Progress, LLC (Duke Energy) owns and operates the coal-fired Mayo
Steam Electric Plant (Mayo, Plant, or Site), located in a rural area approximately 10
miles north of the City of Roxboro in Pearson County, North Carolina (Figure 1-1).
Duke Energy owns the site property, which is roughly bisected by US Highway 501
(Boston Road). The majority of the Plant property is located east of Highway 501,
encompasses 460 acres, and includes the power plant, ash basin, and the majority of
operational features (Figure 1-2). The Mayo Plant began operations in 1983 with a single
727 -megawatt capacity generating coal-fired unit. Coal combustion residuals (CCR)
have historically been managed in the Plant's on-site ash basin (surface impoundment).
CCR were initially deposited in the ash basin by hydraulic sluicing operations. CCR
was managed at the Plant's on-site ash basin and transported via wet sluicing until 2013
when the Mayo Plant converted to a dry ash system in which 90 percent of CCR was
dry. Final system upgrades were completed in October 2016; all CCR collection is dry.
Beginning in November 2014, CCR from the Plant has been managed in the newly
constructed Landfill permitted by the North Carolina Department of Environment
Quality (NCDEQ) Division of Waste Management (NCDEQ-DWM) Permit 7305.
Discharge from the ash basin to Mayo Lake is permitted by the NCDEQ Division of
Water Resources (NCDEQ-DWR) under National Pollutant Discharge Elimination
System (NPDES) Permit NC0038377.
Detailed descriptions of the Site operational history, the Site conceptual model, physical
setting and features, geology/hydrogeology, and results of the findings of the CSA and
other CAMA-related works are documented in full in the following documents:
• Comprehensive Site Assessment Report — Mayo Steam Electric Plant (SynTerra,
September 2, 2015)
• Corrective Action Plan Part 1— Mayo Steam Electric Plant (SynTerra, December 1,
2015)
• Corrective Action Plan Part 2— Mayo Steam Electric Plant (SynTerra, February 2,
2016)
• Comprehensive Site Assessment Supplement 1— Mayo Steam Electric Plant (SynTerra,
July 7, 2016)
• Comprehensive Site Assessment Update —Mayo Steam Electric Plant (SynTerra,
October 31, 2017)
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Ash basin pumping test are planned to collect site-specific data to refine the
groundwater flow and transport model to be used for closure planning and potential
groundwater corrective action evaluation. The pumping tests would focus on
evaluation of field scale horizontal and vertical variability of the hydrologic
characteristics for the saturated media. Each test would provide estimates of media
properties including transmissivity (T), hydraulic conductivity (K), and storativity (S).
The following major tasks are anticipated for well installation and ash basin pumping
test at the Mayo Steam Electric Plant:
1. Well Installation and Development
2. Static Water Level (Baseline Data) Collection
3. Pumping System Installation
4. Step -Drawdown Tests
5. Step Drawdown Test Recovery
6. Constant Rate Pumping Tests
7. Water Quality Sampling
8. Data Analysis
As a portion of this scope of work, both pumping wells and observation wells will be
installed at the Site. One ash pumping well will be installed at a selected location. A
total of six new observation wells will also be installed. Additionally, two existing wells
will be utilized as observation points during the ash pumping test.
One pumping test is estimated to take eight (8) days (72 hours for static conditions, 24
hours for step test/recovery, 72 hours for constant rate discharge test, 24 hours
recovery). During this time, water levels would be monitored in selected wells using
pressure transducers and manual water level readings. Groundwater samples will also
be collected daily during the pumping test for laboratory analysis.
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2.0 SITE CONCEPTUAL MODEL
2.1 Site Geology and Hydrogeology
This section provides a brief summary of the Site geology and hydrogeology. However,
it should be noted that the scope of the aquifer pumping tests will be limited to the ash.
Detailed descriptions of the Site geology and hydrogeology can be found in the
documents listed in Section 1.
2.1.1 Site Geology
The vicinity of the Mayo Plant is generally characterized by mature, well-
rounded hills and rolling rides cut by small streams and drainages. However, in
areas with thinner regolith, like in the immediate vicinity of the Mayo Plant, the
relief is more rugged with incised streams that occur as the rate of subsurface
weathering has failed to keep pace with the rate of erosion.
The Plant is located near the contact between two regional zones of
metamorphosed rocks: the Carolina Slate Belt (often referred to as Carolina
terrane) on the east and the Charlotte Belt (or Charlotte terrane to the west. The
majority of the Mayo Plant, including the largest portion of the ash basin and
Mayo Lake are situated in the Caroline terrane.
The subsurface at Mayo Plant is composed of regolith (including residual soils,
fill and reworked soils, alluvium, and saprolite), transition zone, and bedrock.
Subsurface conditions vary with topography, parent rock, and site infrastructure.
Saprolite is mostly thin (ranging from non-existent to around 25 feet deep) and
almost entirely unsaturated. This generalization is not consistent for the
southern, upland parts of the Site where a thick, saturated saprolite zone is
present nor for certain locations beneath the ash basin. The thin to non-existent
saprolite zone across the central and northern portion of the Site is due to
extensive excavation and reworking of surficial materials during Plant
construction.
A transition zone of partially weathered rock underlies the regolith and is
generally continuous throughout the Mayo Plant area. However, the transition
zone at Mayo Plant is mostly comprised of partially weathered rock that is
gradational between saprolite and competent bedrock. The change from
partially weather rock to the third unit, competent bedrock is subjective and at
Mayo Plant is defined by subtle changes in weathering, secondary staining and
mineralization, core recovery, and the degree of fracturing in the rock.
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Bedrock in the area includes volcanic and sedimentary rocks that have been
metamorphosed, intruded by coarse-grained granitic rocks, and subjected to
regional structural deformation. The shallow bedrock has been fractured;
however, only mildly productive fractures (providing water to wells) were
observed within the top 50 feet of competent rock.
2.1.2 Site Hydrogeology
In general, three hydrogeologic units or zones of groundwater flow can be
described for the Mayo Plant. The zone closest to the surface is the shallow or
surficial flow zone encompassing saturated conditions, where present, in the
residual soil, saprolite, or alluvium beneath the Site. A transition zone is
encountered below the surficial zone and the bedrock as is characterized
primarily by partially weathered rock of variable thickness. The transition zone
is not consistently saturated across the Site. The bedrock flow zone occurs below
the transition zone and is characterized by the storage and transmission of
groundwater in water -bearing fractures.
The Mayo Plant ash basin occupies the former stream valley of Crutchfield
Branch. The basin acts as a bowl -like feature towards which groundwater flows
from the northwest, west, south, and east. Groundwater flows north-northeast
from the ash basin into the small valley formed by Crutchfield Branch.
Groundwater flows from the highest topographic portion of the Site (near the
Plant entrance road) to the north and northeast. The ash basin was formed when
the Crutchfield Branch stream valley was damned. The flow of ponded water
within the ash basin is controlled laterally by groundwater flow that enters the
basin from the east, south, and west and is controlled downgradient (north-
northeast) by the ash basin damn and the NPDES outfall/discharge. The head
created by the ash pore water creates a slight mounding effect that influences the
groundwater flow direction in the immediate vicinity of the ash basin. East of
the ash basin, a groundwater divide separates the Crutchfield Branch flow
regime from the Mayo Lake flow regime.
The vertical gradients are near equilibrium across the Site indicating that there is
no distinct horizontal confining layer beneath the Mayo Plant.
The topographically highest portion of the Site is along the Plant entrance road
just off Highway 501. In general, the topography slopes away from the entrance
road and the power plant area towards Mayo Lake. The power plant area is
situated at an approximate elevation of 520 feet mean sea level (msl) and Mayo
Lake is at an elevation of about 435 feet msl, a vertical difference (relief) of 85
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feet. One small stream traverses the southern end of this portion of the Site
flowing from west to east, originating south of the coal pile, and eventually
flowing into Mayo Lake. Whereas the Piedmont region of North Carolina is
typically characterized by gently rolling hills and ridges, the topography around
the Mayo Plant is steeper with incised streams and deeply cut ridges and inter -
ridge valleys. This steeper topography is attributed to the shallow regolith in the
Plant area that leads to a faster rate of erosion relative to the rate of weathering.
These geomorphic processes were in place prior to the damming of Crutchfield
Branch (to create the ash basin) and Mayo Creek (to create Mayo Lake).
Based on review of the USGS topographic map of the Mayo Plant area prior to
Plant construction, it is apparent that the ash basin now encapsulates the
headwaters of Crutchfield Branch. Topography surrounding the ash basin is
gentler than near Mayo Lake with relief in the range of 60 feet. Surface runoff
drains to the ash basin from the higher areas to the east, south, and west. The
ash basin dam is approximately 2,300 feet long, 400 feet wide at the base, and has
a maximum height of approximately 110 feet. The dam is oriented northwest —
southeast and was completed in October 1982. Recent surveying and
bathymetric studies indicate that the basin has a storage capacity of 1,500 acre-
feet. Two engineered toe drains are located on the downstream side of the dam.
Steep hills are present in the area downslope from the ash basin. Crutchfield
Branch and a small tributary that drains the west toe drain flow north-northeast,
under May Lake Road and off -Site. Deeply cut ridges and valleys occur in the
extreme northern portion of the Site along the North CarolinaNirginia border
and to the east of the ash basin. A small, intermittent stream flows south to north
from the east side of the 1981 C&D landfill, under Mayo Lake Road, and
eventually merges with Crutchfield Branch off -Site prior to crossing the North
CarolinaNirginia state line.
Mayo Lake is the dominant feature on the eastern portion of the Site. Mayo Lake
was formed when Mayo Creek was dammed, and now encapsulates the majority
of the reach of Mayo Creek as well as a number of smaller streams that flowed
into Mayo Creek prior to the lake formation. The 2,800 -acre lake is maintained
by the earthen dam located at the northern end of the lake.
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3.0 WELL INSTALLATION
SynTerra will conduct field oversight of drilling operations and well installations at the
proposed test locations. SynTerra's oversight will include documentation of field
observations and activities associated with well drilling, well installation and well
development activities conducted by a licensed North Carolina driller and support crew
contracted by Duke Energy.
Proposed pumping well and observation well locations and a conceptual well layout
and cross-sectional view are provided on Figure 3-1. A summary of proposed well
construction details for the pumping wells and observation wells is included in Table 3-
1. Proposed well depths and screened intervals are based on boring logs from the
adjacent well clusters ABMW-2 and ABMW-3. Boring logs form these locations have
been included as Appendix A.
3.1 Installation of Pumping and Observation Wells
Prior to the start of any drilling activities at the Site, subsurface utility location will be
conducted in the area of all proposed borings.
3.1.1 Ash Pumping Well Installation
The ash pumping well will be installed using sonic drilling techniques utilizing a
nominal 13 -inch sonic core barrel. The ash pumping well will be drilled to
approximately 80 feet below ground surface (see Table 3-1).
A six-inch schedule 40 PVC well, with a 10 -foot wire -wrapped 0.10 slot PVC
screen will then be installed in the boring. The well will be hung approximately
one foot off the bottom of the boring (to allow filter material below the well
screen).
No. 1 well sand or equivalent filter pack materials will be used. The filter pack
material will be tremie washed in if there is standing water in the bore hole (not
anticipated with sonic drilling). The filter pack will be extended from the base of
the boring to a minimum of five feet above screen interval. Coated bentonite
pellets will be used for the seal and extend a minimum of five feet above the
sand pack. Pellets will be allowed to hydrate for in accordance with
manufactures specifications before grouting. After hydration of the seal, the
remaining annulus will be pressured grouted using a 1-2 percent bentonite 90
percent neat cement mixture (grout mixing should be 5.2-5.75 gallons of water
per 94 pound bag of Portland Type cement). Where a well is installed within 15
feet of an existing monitoring well location, a low pH grout, such as
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AQUAGUARD, should be used. The use of this type of grout is intended to
reduce the potential for grout impacts on existing or nearby monitoring wells.
3.1.2 Ash Observation Well Installation
A total of 6 ash observation wells will be installed at the site. These wells will be
located at 15 feet and 30 feet away from the pumping well. Distance from the
pumping well for each observation well is provided on Table 3-1.
Ash observation wells will be installed using sonic drilling techniques utilizing a
nominal six-inch (or equivalent) core barrel advanced to the target depth (see
Table 3-1).
A two inch schedule 40 PVC well, with a five-foot Vee -Pack PVC screen will then
be installed in the boring. The well will be hung approximately one foot off the
bottom of the boring (to allow filter material below the well screen).
No. 1 (or equivalent) filter pack will be extended from the base of the boring to a
minimum of five feet above Vee -Pack screen interval. Coated bentonite pellets
will be used for the seal. The well seal will be extended a minimum of five feet
above the sand pack. Pellets will be allowed to hydrate in accordance with
manufactures specifications before grouting. After hydration of the seal, the
remaining annulus will be pressured grouted (for grout specifications see section
3.1.1).
3.2 Well Development
The newly installed wells will be developed until discharge is clear and stable. Well
development should include surging and high volume water removal (air lifting or
other methods capable of quickly removing water). Completion of development will be
determined when turbidity remains below 10 Nephelometric Turbidity Units (NTUs) or
5 borehole volumes have been extracted (subject to change based on field observations).
The main objective of the well development is to improve near -well permeability and
stability. The removal of the fine particles from the near -well area will help create a
more permeable zone and minimize the effect of well smear or caking. Improper well
development can cause significant impact to the results of both the step test and the
constant rate discharge test. This could result in the need to stop the test (step test or
constant rate test) and redevelop the wells (primarily pumping wells). Well
development for the pumping wells will be considered complete when no fines are
observed in the well discharge (less than 10 NTUs) after surging the well.
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Once the wells have been fully developed they will be allowed to equilibrate for five
days prior to the collection of baseline water level data.
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4.0 AQUIFER PUMP TEST DATA NEEDS
Aquifer pumping test results will be used to define aquifer characteristics within the
ash basin. Information gathered during aquifer pumping tests will be used to refine the
groundwater flow and transport model. Based on the pumping rates obtained during
well installation, it is anticipated that three-day (72 hours) tests will allow for evaluation
of aquifer properties.
Evaluation of data in the field will ultimately be used to determine the durations. Each
test will be conducted in general accordance with ASTM D 4050-96 (2002).
The following pretest data is needed:
• Geologic characteristics of the subsurface that influence groundwater flow.
The subsurface in the area of the pumping test is composed of ash, saprolite,
transition zone, and bedrock. The aquifer testing will be limited to the ash.
Groundwater flow in the ash (primary test aquifer) is porous media flow. It is
assumed that groundwater flow direction and gradients are primarily
controlled by topography.
• The type of water -bearing zone and its lateral and vertical extent.
The primary water -bearing zone for the aquifer test is the ash. For the purpose
of this test, it is assumed to be infinite in lateral and vertical extent.
• The depth, thickness, and lateral extent of any confining beds.
Observations will be made during drilling operations to identify any confining
beds. It is currently unknown whether the lower ash wells will indicate water
table conditions, partially confined conditions, or confined conditions.
• Location of groundwater recharge.
Groundwater recharge is assumed to be primarily from the ash basin area.
• Horizontal and vertical flow components (e.g., direction, gradient).
Water levels will be measured in the ash monitoring wells to determine the
horizontal and vertical hydraulic gradient in the area of the aquifer test.
Additionally, the multi-level well screens will provide information on potential
stratification within the ash.
Location, construction, and zone of completion of existing wells in the area (see
Table 3-1).
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5.0 AQUIFER PUMPING TEST
5.1 Static Water Level Collection
Static water level (baseline data) collection may commence once the pumping wells and
observation wells have been installed, developed, and allowed to equilibrate (for
approximately five days). Baseline water -level readings will be used to determine long-
term data trends or potential interferences from other pumping/discharge source(s).
Water levels will be monitored in selected wells using pressure transducers. A
summary of the wells to be monitored for each test is included as Table 5-1.
Transducers will be installed in all proposed observation well at the site.
Prior to the installation of transducers, an initial round of water levels will be manually
collected from the wells listed in Table 5-1. Transducers will then be installed and
programmed to collect water level data every 10 minutes for a minimum of 72 hours
before the start of any active pumping (step test). At the end of the 72 -hour period,
baseline measurements would be stopped and downloaded for review.
5.2 Pumping System Installation
Once baseline conditions have been established, a submersible pump would be installed
in the pumping well by the Duke well installation contractor.
The Duke well installation contractor will provide and install a flow meter capable of
continuously logging discharge rates and total flow in-line with the pump discharge
line. The flow meter will need to be installed in such a way as to allow it to be full of
water at all times. This can be done by the installation of a six-inch drop in the
discharge line prior to the flow meter and a subsequent 6 inch rise in the discharge line
past the flow meter. A minimum of one foot of straight piping will also need to be
installed after the drop and before the rise to ensure laminar flow through the
transducer. Two ball valves should be installed in the discharge line. One should be
located prior to the drop and one should be located post rise. A photograph showing
the general proposed configuration for the flow meter is presented on Figure 5-1. A
small diameter sampling port should also be installed somewhere near the flow meter
to allow for taking field water quality measurements and samples. The remaining
discharge line should be extended away from the test area (300-500 feet) to minimize
potential influence of the discharged groundwater.
5.3 Step -Drawdown Test
After the pumping system has been installed, the well will be allowed to fully recover
(assumed to be 12 hours). Once the pumping well has fully recovered, SynTerra in
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conjunction with the drilling contractor will conduct a step -drawdown test. A typical
step test drawdown curve is presented in Figure 5-2.
A step -drawdown test (or step test) is a single -well pumping test designed to
investigate the performance of a pumping well under controlled variable discharge
conditions. During the step -drawdown test, an initial rate of one gallon per minute
(gpm) would be used. The discharge rate would be increased approximately five gpm
per step period (subject to change based on field observations). Each step would be
approximately 2 hours (subject to change based on field observations). This duration
should allow wellbore storage effects to dissipate. This process would continue until the
well can no longer sustain the selected flow rate (curve does not flatten out) or a
maximum of 20 gpm flow rate is reached. After completion of the step test, the
pumping well would be allowed to return to static conditions (recovery tests).
Data from the step test will be used to determine an appropriately conservative initial
pumping rate (Qmax) for the constant rate pumping tests. A Qmax should be calculated
that will result in a drawdown after 72 hours that is approximately 25 percent of the
water column (see Section 5.2). At the end of the test the flow will be adjusted to the
selected Qm. using one of the ball valves prior to shutting down the pump. As the
pump is shut down the remaining ball valve will be closed to prevent the discharge line
from draining into the well (which would affect recover data).
5.4 Step Test Recovery
Once the step test is complete, the pump will be shut off and the flow meter will be
isolated (using ball valves upstream and downstream of the flow meter). The well will
be allowed to fully recover prior to the start of the constant discharge test. It is
anticipated that recovery will take less than 12 hours. Water levels will continue to be
monitored at the same frequency during recovery.
Once recovery is complete, the transducers water -level readings will be stopped and the
data downloaded and analyzed.
5.5 Constant -Rate Pumping Test
Once the step -drawdown test has been completed and water levels in the pumping well
and affected observation wells have returned to static conditions and transducers have
been stopped and reprogramed, a constant -rate pumping test will be conducted. Prior
to the start of any active pumping a round of water levels will be collected in the
monitored wells for each test location (see Table 5-1)
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A constant -rate pumping test involves a control well that is pumped at a constant rate
while water -level response (drawdown) is measured in one or more surrounding
observation wells and in the pumping well. The goals of a constant -rate pumping test
are to estimate hydraulic properties of a saturated porous media such as T, K, and S and
to identify potential boundary conditions that may exist.
Discharge rate would be measured approximately every 15 minutes during the initial
portion of the test (first four hours). If discharge rate is stable, flow readings will be
collected at 8 -hour intervals for the remainder of the test. Water level transducers will
be set to record measurements every minute for the duration of the 72 -hour test and
recovery period. Discharge water will be routed to the active ash basin in the
approximate locations depicted on Figure 3-1.
Once pumping has started, the test will run uninterrupted for up to 72 hours. During
that period, water -levels will be continuously monitored with data logging pressure
transducers and flow measurements continuously recorded (24 hours per day) with an
electronic flow meter that averages measurements at five minute intervals. Manual
water -level readings would be collected every two hours at each selected well during
active pumping to provide automated data backup (see Table 5-1). Manual water -level
readings will also be collected twice daily at monitoring wells ABMW-3S, ABMW-4,
ABMW-4S, and SMP -1. Manual flow measurements may be conducted based on field
observations, as described earlier in this section. Ground water quality field readings
and laboratory samples will be collected from the discharge at selected intervals during
active pumping (see Section 4.0).
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6.0 WATER -QUALITY MEASUREMENTS AND SAMPLING
In order to help identify the potential geochemical changes that may accrue in the ash
pore water during the active pumping, water -quality data will be collected during each
pumping test. Water -quality data will include the collection of both field reading and
laboratory samples. Particular emphasis will be placed on collection of conductivity
and pH data. Changes in water chemistry (conductivity and pH) may indicate contact
with a recharge boundary. Groundwater samples will be collected from the pumping
well discharge and analyzed for IMP constituent list.
Water -quality measurements will be collected from the discharge during the entire
constant rate discharge test. Readings of pH, specific conductance, temperature,
dissolved oxygen, oxidation reduction potential, Eh, and turbidity will be collected once
every hour during the test. To facilitate this, a YSI Pro Plus water -quality meter will be
plumbed into the discharge line. Flow through the meter will be regulated with both
upstream and downstream valves.
Water -quality samples for laboratory analysis will be collected prior to the step -
drawdown test and once per day during the constant rate pumping test from each of
the pumping wells. Each sample will be collected from a sampling port plumbed into
the discharge line. Water will be collected in laboratory -prepared sample bottles and
immediately placed on ice under strict chain -of -custody.
Page 6-1
P: \ Duke Energy Progress.1026\ 105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping
Test\Ash Basin Pumping Test Work Plan\Mayo Ash Basin Pumping Test Work Plan FINAL.docx

Ash Basin Pumping Test Work Plan July 2, 2018
Mayo Steam Electric Plant SynTerra
7.0 ANALYSIS OF WATER -LEVEL DATA
Analysis of water -level fluctuations in monitoring wells will be initially conducted
using Aqtesolv® Version 4.5. Baseline data, step test data, constant rate discharge data
(pumping test), drawdown data, and analytical results will be summarized and
included as part of a technical memorandum on the results of aquifer testing.
7.1 Baseline Analysis
Baseline data will be evaluated to determine whether any long-term trends or
interference from nearby production wells are observable. If long-term data trends are
observed, the baseline data will be used to adjust the pumping test drawdown data to
compensate for the observed trend.
7.2 Step Test Analysis
Step test analysis will be conducted in the field. The Theis (1935) step -drawdown
procedure will be used to analyze data. Additional analytical methods (Dougherty -
Badu, 1984; Hantush-Jacob, 1955; Theis, 1935; and Hantush, 1961) may be used
depending on results of the step test drawdown data.
Step test results will be used to calculate a flow rate that will result in a drawdown of
approximately 25 percent of the saturated thickness after 72 hours (and excel spread
sheet will be provided for making these calculations).
7.3 Constant Discharge Rate Test Analysis
Final analysis methods of drawdown data are dependent on actual results of the
tests. Initially, it is assumed that the proposed ash pumping wells are unconfined.
Additionally, drawdown may be observed only in the pumping well. This will result in
analysis of the data as a single -well pumping test. If data indicates drawdown in one or
more observation well, the test will be analyzed as a multiple -well pump
test. Suggested analytical methodologies for data analysis of both single -well and
multiple -well pump tests are outlined in the Technical Guidance Manual for
Hydrogeologic Investigations and Groundwater Monitoring, Chapter 4, Slug and
Pumping Test, Table 4.2 (single -well pump test) and Table 4.7 (multiple -well pump test)
(Clemson, February 1995) at: httj2://www.clemson.edu/cesftdro/murdoch/PDF`/`
20Files/Pumping%20tests, %20EPA%20guidance.12df
Page 7-1
P:\Duke Energy Progress.1026\ 105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping
Test\Ash Basin Pumping Test Work Plan\Mayo Ash Basin Pumping Test Work Plan FINAL.docx

Ash Basin Pumping Test Work Plan July 2, 2018
Mayo Steam Electric Plant SynTerra
8.0 REFERENCES
Daniel, C. C., & Dahlen, P. R. (2002). Preliminary hydrogeologic assessment and study plan
for a regional ground -water resource investigation of the Blue Ridge and Piedmont provinces
of North Carolina. Raleigh, North Carolina: U.S. GEOLOGICAL SURVEY Water -
Resources Investigations Report 02-4105.
Dougherty, D.E and D.K. Babu, 1984. Flow to a partially penetrating well in a double
porosity reservoir, Water Resources Research, vol. 20, no. 8, pp. 1116-1122.
Hantush, M.S. and C.E. Jacob, 1955. Non -steady radial flow in an infinite leaky aquifer, Am.
Geophys. Union Trans., vol. 36, pp. 95-100.
Hantush, M.S., 1961b. Aquifer tests on partially penetrating wells, Jour. of the Hyd. Div.,
Proc. of the Am. Soc. of Civil Eng., vol. 87, no. HY5, pp. 171-194.
LeGrand, H. (2004). A master conceptual model for hydrogeological site
characterization in the Piedmont and Mountain Region of North Carolina: A
guidance manual. North Carolina Department of Environment and Natural Resources,
Division of Water Quality, Groundwater Section, Raleigh, NC, 55.
Theis, C.V., 1935. The relation between the lowering of the piezometric surface and the rate and
duration of discharge of a well using groundwater storage, Am. Geophys. Union Trans.,
vol. 16, pp. 519-524.
Page 8-1
P: \ Duke Energy Progress.1026\ 105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping
Test\Ash Basin Pumping Test Work Plan\Mayo Ash Basin Pumping Test Work Plan FINAL.docx

Ash Basin Pumping Test Work Plan July 2, 2018
Mayo Steam Electric Plant
FIGURES
SynTerra
P:\ Duke Energy Progress.1026\ 105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping
Test\Ash Basin Pumping Test Work Plan\Mayo Ash Basin Pumping Test Work Plan FINAL.docx

HALIFAX COUNTY - -
PERSON COUNTYY Y- %
• `S N
RRo ;
//..
��♦
i
001,
•
J:.-.. .-...- :_, ♦ ♦ R.O. W. 70�, .cx:• -
I ,R
♦
� 1
/P ♦ I3 '
O
Q- I O
l4
�'' 0
-.l N
A
�.
-. ;Y., --�-�,----------
',� f , •'qtr,
4.'
e - MULUNSLN
IE
PERSON
410
VnTem
;DUKE
ENERGY
IGRAPHIC SCALE
600 300 0 600 1,200
1148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PHONE [phone]
DRAWN BY: A. ROBINSON DATE: 02/27/2018
CHECKED BY: K. DONOVAN
PROJECT MANAGER: J. WYLIE
CAROLINA -VIRGINIA STATE
(APPROXIMATE)
LEGEND
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
DUKE ENERGY PROGRESS MAYO PLANT
- " - SITE BOUNDARY
STREAM
NOTES:
PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY PROGRESS.
AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON JULY 13, 2017.
AERIAL WAS COLLECTED ON JUNE 13, 2016.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM RIPS 3200 (NAD83/2011).
FIGURE 1-2
MAYO PLANT VICINITY MAP
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

CONCEPTUAL LAYOUT, ACTUAL LOCATIONS FOR
PUMPING WELLS AND OBSERVATION WELLS WILL
BE FIELD VERIFIED
1 rr+rnin
O
PROPOSED OBSERVATION WELL (UPPER ASH PORE WATER)
O
PROPOSED OBSERVATION WELL (MEDIUM ASH PORE WATER)
0
PROPOSED OBSERVATION WELL (LOWER ASH PORE WATER)
0
PROPOSED PUMPING WELL (ASH PORE WATER)
ABMW-26R
WELL IN BEDROCK
ABMW-2
WELL IN ASH PORE WATER
ABMW 4D
WELL IN TRANSITION ZONE
ABMW-3S
WELL IN ALLUVIUM/SAPRO LITE
' ,•
ASH BASIN WASTE BOUNDARY (APPROXIMATE)
10 BGS
DISCHARGE LINE (APPROXIMATE)
BGS
BELOW GROUND SURFACE
CONCEPTUAL PROPOSED PUMPING TEST
WELL SCHEMATIC
AP -6
PROPOSED UPPER ASH WELLS
A�i!H PUMPING WELL
GROUND
GROUND
SURFACE
' ,•
SURFACE
10 BGS
i
10 BGS
20 BGS
20 BGS
30 BGS
a •
y ` .
30 BGS
PROPOSED M
ASH
ASH WELLS
.
40 BGS
50 BGS
50 BGS
S
60 oMpoc,
!
60 BGS
70
70 BGS
80 BGS 5 FEET
SAPROLITE
80 BGS
90 BGS
BEDROCK
90 BGS
100 BGS
100 BGS
e le l§O
FORMER CRUTCHFIELD BRANCH
AP -6 (PERENNIAL) BASED ON 1968
(ASH PUMPING TEST) USGS TOPOGRAPHIC MAP
• PUMPING WELL
SCREENED 70-80 FEET BGS `
6 -INCH WIRE WRAPPED PVC SCREEN.
6 -INCH WELL PVC CASING k,r
F Y
OBSERVATION WELLS CLUSTER -
SET 15 FEET FROM PUMPING WELL
2 -INCH WELL
• UPPER ASH (SCREENED 10-20 FEET BGS) .t
• MEDIUM ASH (SCREENED 40-50 FEET BGS) - z
• LOWER ASH (SCREENED 70-80 FEET BGS)
SET 30 FEET FROM PUMPING WELL / J
2 -INCH WELL
• UPPER ASH (SCREENED 10-20 FEET BGS) \
• MEDIUM ASH (SCREENED 40-50 FEET BGS)
• LOWER ASH (SCREENED 70-80 FEET BGS)
/
/ I ,
i
/ I
BMW -MR -
ABMW-2BRL ABMW-2
i
s
FORMER INTERMITTENT STREAM BA
ON 1968 USGS TOPOGRAPHIC MAP
,Y o
j � vvvv vv y;
,
ABMW-3S
ABMW-3
F.
wKs
F
T
A -
°�BMW4D
,�
V
\ V
I
i E �
DUKE
ENERGY
PROGRESS
r ••� . r Terra MAYO STEAM ELECTRIC PLANT
10660 BOSTON RD
ROXBORO, NORTH CAROLINA
GRAPHIC SCALE
100 0 100
IN FEET
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PHONE [phone]
www.synterracorp.com
DRAWN BY: CHRIS BRUCE DATE: 02/19/18
PROJECT MANAGER: JERRY WYLIE
LAYOUT: FIG 1 (PROP WELL)
nFro�ionaa rnF Pnn c�nuP c„P.m, c.,,a.P«�ma�,n
PROPOSED LOCATIONS FOR
ASH BASIN PUMPING TESTS
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

-
f _
BALL VALVE
FLOW METER CONFIGURATION
�mom
Rise -post flow meter`"
LAMINAR FLOW SECTIONS
• (12 -INCHES PER AND POST METER)
THISSH41.
OWSSHOWS THE GENERAL CONFIGURATION OF THE DISCHARGE LINE AND FLOW METER.
FLOW METER TYPE MAY VARY BUT SHOULD FOLLOW THIS GENERAL CONFIGURATION.
�r L,.
i 7 ..
ylv■nTAFa&VIS

0
in
SOURCE:
25
20
10
R]
STEP DRAWDOWN TEST
i a t
* 1
■ a r
i 1 +
i 1 +
a 1 ■
■ 1 4
� ! r
� 1
■
6411.■i!##�F#•4■#*!#l�yt�tt■*#■t•a7i•##ttli•i4■•fii ii■#a■•r■lM if■!*!*#i •F!•i F#■* ###■r##•#!p•■ill
■ !
r
i 1
k 1
i
F
"STEP" PORTION OF CURVE
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VE a
:ir.r4t.... t... t. i.. iti­..t..•i t t t. air#- t t t t f t.ii. t t. r f t. i•afi■Frr
rr. rrt t#rd r i+
"FLAT" PORTION OF CURVE
tf■•ttats.■ ..........................#rttftta■c•t:tis
•
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r 1 �
� Y
i 1 i
4 1 ■
� 1 4
� ! r
k +
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i a F
! ■
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a 1 ■
a 1 r
i ! r
■ r r
� 1
� ! F
� 1 4
� 1
f 4
r � r
MLU (Multi -Layer Unsteady state)
http://www.microfem.ni/products/mlu.html
1F
Time [h ]
fis
RECOVERY PORTION OF CURVE
h
•
i
t. a i■ s ti t t}
...........
f■isas.f.. .+....s.a
•
i
r
i
+
f
4
farsr�iiia�irrararrararararai■irar•�•
4
4
i
r
i
25
Pumping Period 1, Layer: 1
Pumping Period 2, Layer: 1
Pumping Period 3, Layer: 1
Pumping Period 4, Layer: 1
Pumping Period 5, Layer: 1
Pumping Period 6, Layer: 1
Pumping Period 7, Layer: 1
♦ Pumping Period 1
0 Pumping Period 1
Pumping Period 1
♦ Pumping Period 1
E Pumping Period 1
Pumping Period 1
♦ Recovery Period

Ash Basin Pumping Test Work Plan July 2, 2018
Mayo Steam Electric Plant
TABLES
SynTerra
P:\ Duke Energy Progress.1026\ 105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping
Test\Ash Basin Pumping Test Work Plan\Mayo Ash Basin Pumping Test Work Plan FINAL.docx

TABLE 3-1
PROPOSED WELL CONSTRUCTION DETAILS
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Identification
Well Purpose
Distance from
Pumping Well
(feet)
Monitoring
Zone
Borehole
Diameter
(inches)
Well
Diameter
(inches)
Casing Depth
(feet BGS)
Total Well
Depth'
(feet BGS)
Screen
Length
(feet)
Ash Basin
AP -6 Ash Well
Pumping
NA
Lower Ash
13.25
6
NA
80
10
AP -6 Upper Ash
Observation
15
Upper Ash
6.25
2
NA
20
10
AP -6 Medium Ash
Observation
15
Medium Ash
6.25
2
NA
50
10
AP -6 Lower Ash
Observation
15
Lower Ash
6.25
2
NA
80
10
AP -6 Upper Ash
Observation
30
Upper Ash
6.25
2
NA
40
10
AP -6 Medium Ash
Observation
30
Medium Ash
6.25
2
NA
66
10
AP -6 Lower Ash
Observation
30
Lower Ash
6.25
2
NA
40
10
ABMW-2 (Existing)
Observation
TBD
Ash
NA
2
NA
39.2
5
ABMW-3 (Existing)
Observation
TBD
Ash
NA
2
NA
40.5
5
Prepared by: CHB Checked by: JAW
Notes:
Proposed depths and well construction details are approximate and subject to change based on field observations
Bold - Indicates Proposed Wells
"'Total Well Depth" is the depth to the bottom of the screened interval, as measured durinq well installation.
BGS - Below ground surface
NA - Not applicable
TBD - to be determined
P:\Duke Energy Progress. 1026\105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping Test\Ash Basin Pumping Test Work Plan\Tables\Table 3-1 Proposed Well
Construction Details—Mayo Page 1 of 1

TABLE 5-1
PROPOSED WELLS TO BE MONITORED DURING ASH BASIN PUMPING TEST
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Well ID
PROPOSED WELL CLUSTER
Step Test
(Ash)
Pumping Test Z
(Ash)
AP -6 Ash Pumping Well
X
AP -6 Upper Ash (15 feet)
X
AP -6 Medium Ash (15 feet)
X
AP -6 Lower Ash (15 feet)
X
AP -6 Upper Ash (30 feet)
X
X
AP -6 Medium Ash (30 feet)
X
AP -6 Lower Ash (30 feet)
X
ABMW-2
X
ABMW-3
X
Prepared by: CHB Checked by: JAW
Notes•
Refer to Scope of Work for frequency of manual water level measurements
P:\Duke Energy Progress. 1026\105. Mayo Ash Basin GW Assessment Plan\Ash Basin Pumping Test\Ash Basin Pumping Test\Ash Basin
Pumping Test Work Plan\Tables\Table 5-1 Proposed Wells to be MonitoredTable 5-1 Proposed Wells to be Monitored Page 1 of 1

Ash Basin Pumping Test Work Plan July 2, 2018
Mayo Steam Electric Plant
APPENDIX A
BORING LOGS FOR
ABMW-2 AND ABMW-3 WELL CLUSTERS
SynTerra
P:\ Duke Energy Progress.1026 \ 105. Mayo Ash Basin GW Assessment Plan\ Ash Basin Pumping Test\ Ash Basin Pumping
Test \Ash Basin Pumping Test Work Plan \Mayo Ash Basin Pumping Test Work Plan FINAL.docx

PROJECT: Mayo Station
PROJECT NO: 1026.105
WELL / BORING NO: ABMW-02
STARTED: 5/30/15 COMPLETED: 5/31/15
NORTHING: 1012778.26 EASTING: 2030477.81
G.S. ELEV: 490.68 ft M.P. ELEV: 492.90 ft
DEPTH TO WATER: ft TOC TOTAL DEPTH: 41.2 ft BGS
LOGGED BY: J. Wylie CHECKED BY: E. Black
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
BOREHOLE DIAMETER: 61N
NOTES:
a
w"
o
U
0_0 0
<
U
U)
DESCRIPTION
a-
Q
�
0�
w �-
�
p z
m �
U
o f
a s
WELL
CONSTRUCTION
5
10
15
20
25
30
35
No recovery.
BOTTOM ASH, dark gray, moist, mostly fine to coarse
sand.
No recovery.
Grout
2" Sch. 40 threaded PVC
riser
—Bentonite seal
''° —Sand Pack
2" pre -packed well screen
'
BOTTOM ASH, dark gray, moist, mostly fine to coarse
sand, some gravel/coal fragments.
BOTTOM ASH, same as above at 8 ft.
FLY ASH, black, saturated, mostly fine sand, little silt,
dense.
BOTTOM ASH, same as above.
No recovery.
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
No recovery.
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
No recovery.
ML
SILT, tan, moise, mostly silt with some fine to medium
sand.
Mottled tan/gray, dry, very dense, weathered gneiss.
(SAPROLITE)
SynTerra CLIENT: Duke Energy Progress, LLC.
L�148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
�T� Greenville, ling 29601
erPhone:864-421-9999 PAGE 1 OF 2

PROJECT: Mayo Station
WELL / BORING NO: ABMW-02
PROJECT NO: 1026.105
STARTED: 5/30/15 COMPLETED: 5/31/15
NORTHING: 1012778.26 EASTING: 2030477.81
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 490.68 ft M.P. ELEV: 492.90 ft
BOREHOLE DIAMETER: 6 IN
DEPTH TO WATER: ft TOC TOTAL DEPTH: 41.2 ft BGS
NOTES:
LOGGED BY: J. Wylie CHECKED BY: E. Black
a
Uui
0-0
Q
o
co
O Z
0 a
WELL
wo
DESCRIPTION
Q
Lu `�
0
a n
CONSTRUCTION
m
45
50
55
60
65
70
75
CLIENT: Duke Energy Progress, LLC.
SynTerra
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
Greenville, South Carolina 29601
s)mTerm Phone: [phone] PAGE 2 OF 2

PROJECT: Mayo Station
WELL / BORING NO: ABMW-02BR
PROJECT NO: 1026.105
STARTED: 5/28/15 COMPLETED: 6/3/15
NORTHING: 1012781.97 EASTING: 2030476.42
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 490.65 ft M.P. ELEV: 493.85 ft
BOREHOLE DIAMETER: 61N
DEPTH TO WATER: ft TOC TOTAL DEPTH: 120.0 ft BGS
NOTES:
LOGGED BY: J. Wylie CHECKED BY: E. Black
a
w"
o
U
Q-0 0
<
U
U)
DESCRIPTION
a
Q
U)
0�
w �-
�
p z
m �
U
o f
a s
WELL
CONSTRUCTION
No recovery.
BOTTOM ASH, dark gray, moist, mostly fine to coarse
sand.
5
'
No recovery.
BOTTOM ASH, dark gray, moist, mostly fine to coarse
sand, some gravel/coal fragments.
10
BOTTOM ASH, same as above at 8 ft.
FLY ASH, black, saturated, mostly fine sand, little silt,
dense.
15
BOTTOM ASH, same as above.
No recovery.
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
20
2" Sch. 40 threaded PVC
BOTTOM ASH, same as above.
riser
FLY ASH, same as above 12.3 ft.
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
25
No recovery.
30
BOTTOM ASH, same as above.
FLY ASH, same as above 12.3 ft.
No recovery.
35
ML
SILT, tan, moise, mostly silt with some fine to medium
sand.
Mottled tan/gray, dry, very dense, weathered GNEISS.
(SAPROLITE)
SynTerra CLIENT: Duke Energy Progress, LLC.
L�148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
Greenville, ling 29601
�T�
erPhone:864-421-9999 PAGE 1 OF 4

PROJECT: Mayo Station
WELL / BORING NO: ABMW-02BR
PROJECT NO: 1026.105
STARTED: 5/28/15 COMPLETED: 6/3/15
NORTHING: 1012781.97 EASTING: 2030476.42
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 490.65 ft M.P. ELEV: 493.85 ft
BOREHOLE DIAMETER: 6 IN
DEPTH TO WATER: ft TOC TOTAL DEPTH: 120.0 ft BGS
NOTES:
LOGGED BY: J. Wylie CHECKED BY: E. Black
o
wo
Uui
0-0
Q
DESCRIPTION
Q
o
w `�
co
O Z
m 0
0 a
a n
WELL
CONSTRUCTION
NN
Grout
6" PVC surface casing
45
Mottled, dark brown, tan, gray, and black, very dense,
dry, saprolitic (schist).
50
Same as above.
55
Same as above.
60
Same as above, strong relict structure, more gneissic
structure/texture.
65
_
RK
Same as above, becoming harder with depth, mostly
rock fragments above 66 W, schistose texture,
saprolite/partially weathered rock contact at 67 ft.
70
No recovery.
5
75
No recovery from 75-77 ft.
RK
Partially weathered rock/bedrock transition from 77-80
ft. Hard, fresh to slightly weathered GRANITIC
GNEISS, iron and manganese staining on joint
surfaces, dry.
SynTerra CLIENT: Duke Energy Progress, LLC.
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
Greenville, South Carolina 29601
s)mTerm Phone: [phone] PAGE 2 OF 4

PROJECT: Mayo Station
WELL / BORING NO: ABMW-02BR
PROJECT NO: 1026.105
STARTED: 5/28/15 COMPLETED: 6/3/15
DRILLING COMPANY: Cascade Drilling
NORTHING: 1012781.97 EASTING: 2030476.42
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 490.65 ft M.P. ELEV: 493.85 ft
BOREHOLE DIAMETER: 6 IN
DEPTH TO WATER: ft TOC TOTAL DEPTH: 120.0 ft BGS
NOTES:
LOGGED BY: J. Wylie CHECKED BY: E. Black
o
wo
Uui
0_0
<
0
Q
�
DESCRIPTION
Q
U
o
w `�
co
O Z
m 0
U
o a
a n
WELL
CONSTRUCTION
Black with thin white bands on folliations, fresh,
PHYLLITE fracture breaks along planes of foliation, top
of bedrock designated at –80 ft.
85
-
Hard, slightly weathered to fresh, medium grained,
GRANITIC GNEISS.
�— Bentonite seal
90
_
-
Hard, fresh, medium grained, GRANITIC GNEISS, few
closely spaced tight breaks along foliation planes with
no staining or mineralization. High angle fracture at
90.8-91 ft. with mineralized joint surface. Vertical
95
,,_ -"
_
-
fracture/intersecting horizontal fracture at 94.4-95 ft.,
brownish -red surface staining on joint plane. 95-96' no
recovery, 97-100 ft. hard, fresh to slightly weathered,
medium grained GRANITIC GNEISS fractures at 97.3,
99 (healed), 99.3-99.6 ft. Joint surfaces, stained
-"
reddish -brown.
-
J9
Sand Pack
100
2" pre -packed well screen
- -`
Hard, GRANITIC GNEISS, weathered with abundant
- -
fractures and reddish brown mineralization, mostly
healed fracture in bottom 6-8".
Abrupt rock change/contact. Black, fresh, fine grained
105
HORNBLENDE GNEISS with 90% mafic minerals with
reddish orange staining on felsic crystallization.
Quartzite vein.
Hard, GRANITIC GNEISS, moderately weathered with
horizontal and vertical fractures some healed).
110
No recovery.
Moderate to severely weathered, dark gray
115
GRANITOID GNEISS, grades into more felsic light gray
GRANITOID GNEISS with some horizontal and vertical
fractures and red -orange mineralization/staining at
joints.
Light gray, moderately weathered GRANITOID
GNEISS with moderate to high angle bedding planes.
Horizontal fractures at 117.5, 118.2, 118.5, and 119 ft.
I
I
I
I
Sharp co tact into dark gray. fine grained PHYLLITF
SynTerra CLIENT: Duke Energy Progress, LLC.
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
Carolina 29601
erPhone:864 421 PAGE 3 OF 4
s)mTraGreenville, 9

PROJECT: Mayo Station
WELL / BORING NO: ABMW-02BR
PROJECT NO: 1026.105
STARTED: 5/28/15 COMPLETED: 6/3/15
NORTHING: 1012781.97 EASTING: 2030476.42
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 490.65 ft M.P. ELEV: 493.85 ft
BOREHOLE DIAMETER: 6 IN
DEPTH TO WATER: ft TOC TOTAL DEPTH: 120.0 ft BGS
NOTES:
LOGGED BY: J. Wylie CHECKED BY: E. Black
a
Uui
0-0
Q
o
co
O Z
0 a
WELL
wo
DESCRIPTION
Q
w `�
0
a n
CONSTRUCTION
m
with high angle rough joint Trom119-120 ft.
Boring terminated at 120 ft. Bentonite added to boring
from 106-120 ft. to facilitate well construction.
125
130
135
140
145
150
155
CLIENT: Duke Energy Progress, LLC.
SynTerra
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
Greenville, South Carolina 29601
s)mTerm Phone: [phone] PAGE 4 OF 4

PROJECT: Mayo Station
PROJECT NO: 1026.105
WELL / BORING NO: ABMW-03
STARTED: 5/18/15 COMPLETED: 5/19/15
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
BOREHOLE DIAMETER: 6 IN
NOTES:
NORTHING: 1012714.21 EASTING: 2030856.72
G.S. ELEV: 497.34 ft M.P. ELEV: 500.17 ft
DEPTH TO WATER: ft TOC TOTAL DEPTH: 40.5 ft BGS
LOGGED BY: J. Wylie CHECKED BY: E. Black
a
wo
Uui
0_0
DESCRIPTION
a-
Q
() o
w `�
co
O
m 0
a
o n
WELL
CONSTRUCTION
5
10
15
20
25
30
35
No recovery.
Grout
2" Sch. 40 threaded PVC
riser
�— Bentonite seal
—Sand Pack
2" pre -packed well screen
'
BOTTOM ASH, black, dry, loose, mostly fine to
medium sand, poorly graded with some small gravel.
No recovery.
FLY ASH, dark gray, wet, silt.
BOTTOM ASH, medium grained, loose, dry, mostly fine
to coarse sand with some small gravel.
No recovery.
Hole collapse material.
FLY ASH, dark gray, dry, mostl silt, few
.x
�ne�nd.
Same as 8.6'.
FLY ASH, darkgray,moist, mostly silt, fe
BOTTOM ASH, medium gray, mostly fine sand, moist,
e silt.
TTOM ASH, light to medium gray with tan and
tV�wn,dry, mostly fine to coarse sand with gravel
ces.
I
x z '
xt '
Y ASH, ra , wet, mostly silt, few fine sand.
BOTTOM ASH, light to medium gray, moist, mosjto
to coarse sand, few silt.
FLY ASH, dark gray, saturated, mostly silt, few fi
coarse sand.
BOTTOM ASH, light green/gray, medium to coarse
sand, moist, loose.
FLY ASH, medium to dark gray, mostly silt, moist,
some fine sand.
BOTTOM ASH same as 21.3 ft.
FLY ASH, same as 23.3 ft.
BOTTOM ASH same as 21.3 ft.
FLY ASH, same as 23.3 ft.
BOTTOM ASH, gray, loose, fine to coarse sand, mois
with small lens of silt and gravel 25.6-25.8 ft.).
Interbedded FLY and BOTTOM ASH.
FLY ASH, dark gray, wet/saturated, silt.
Interlayered and interbedded FLY ASH and BOTTOM
ASH layers, recovery only a few inches thick.
SynTerra CLIENT: Duke Energy Progress, LLC.
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
s)mTraGreenville, 9Carolina 29601
erPhone:864 421 PAGE 1 OF 2

PROJECT: Mayo Station
WELL / BORING NO: ABMW-03
PROJECT NO: 1026.105
STARTED: 5/18/15 COMPLETED: 5/19/15
NORTHING: 1012714.21 EASTING: 2030856.72
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 497.34 ft M.P. ELEV: 500.17 ft
BOREHOLE DIAMETER: 6 IN
DEPTH TO WATER: ft TOC TOTAL DEPTH: 40.5 ft BGS
NOTES:
LOGGED BY: J. Wylie CHECKED BY: E. Black
a
U
a 0
U
a
O o
co
0 z
0 Q
WELL
w
< J
DESCRIPTION
Q
w �-
m 0
a
CONSTRUCTION
45
50
55
60
65
70
75
CLIENT: Duke Energy Progress, LLC.
SynTerra
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
Greenville, South Carolina 29601
s)mTerm Phone: [phone] PAGE 2 OF 2

0
ao
g
a
0
Cn
z
z
0
PROJECT: Mayo Station
WELL / BORING NO: ABMW-03S
PROJECT NO: 1026.105
STARTED: 5/20/15 COMPLETED: 5/20/15
NORTHING: 1012718.52 EASTING: 2030858.24
DRILLING COMPANY: Cascade Drilling
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 497.33 ft M.P. ELEV: 500.30 ft
BOREHOLE DIAMETER: 61N
DEPTH TO WATER: ft TOC TOTAL DEPTH: 68.0 ft BGS
NOTES:
LOGGED BY: E. Black CHECKED BY: J. Wylie
a
w V
o
U
Q-0 0
<
(D
U)
DESCRIPTION
o-
Q
U)
0�
w �-
�
p z
m �
U
o f
a s
WELL
CONSTRUCTION
No recovery.
BOTTOM ASH, black, dry, loose, mostly fine to
medium sand, poorly graded with some small gravel.
5
'
No recovery.
FLY ASH, dark gray, wet, silt.
BOTTOM ASH, medium grained, loose, dry, mostly fine
10
' r
to coarse sand with some small gravel.
No recovery.
Hole colla se material.
FLY ASH, dark gray, dry, mostlysilt, few fine sand.
Same as 8.6 ft.
FLY ASH, dark gray, moist, most) silt, few clay.
15
.x
BOTTOM ASH, medium gray, mostly fine sand, moist,
e silt.
x z '
TTOM ASH, light to medium gray with tan and
xt '
tV�wn,dry, mostly fine to coarse sand with gravel
20
ces.
Y ASH, ra , wet, mostly silt, few fine sand.
BOTTOM ASH, light to medium gray, moist, mostly fi
to coarse sand, few silt.
FLY ASH, dark gray, saturated, mostly silt, few fine to
coarse sand.
Grout
BOTTOM ASH, light green/gray, medium to coarse
sand, moist, loose.
FLY ASH, medium to dark gray, mostly silt, moist,
25
some fine sand.
BOTTOM ASH same as 21.3 ft.
FLY ASH, same as 23.3 ft.jr
BOTTOM ASH same as 21.3 ft.
FLY ASH, same as 23.3 ft.
BOTTOM ASH, gray, loose, fine to coarse sand, mois
with small lens of silt and gravel 25.6-25.8 ft.).
30
Interbedded FLY and BOTTOM ASH.
2" Sch. 40 threaded PVC
riser
FLY ASH, dark gray, wet/saturated, silt.
35
Interlayered and interbedded FLY ASH and BOTTOM
ASH layers, recovery only a few inches thick.
SynTerra CLIENT: Duke Energy Progress, LLC.
148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
South ling 29601
rPhone:Greenvllle,
synTera 864-421-9999 PAGE 1 OF 2

PROJECT: Mayo Station WELL / BORING NO: ABMW-03S
PROJECT NO: 1026.105 STARTED: 5/20/15 COMPLETED: 5/20/15
DRILLING COMPANY: Cascade Drilling
NORTHING: 1012718.52 EASTING: 2030858.24
DRILLING METHOD: Rotary Sonic
G.S. ELEV: 497.33 ft M.P. ELEV: 500.30 ft
BOREHOLE DIAMETER: 6 IN
DEPTH TO WATER: ft TOC TOTAL DEPTH: 68.0 ft BGS
NOTES:
LOGGED BY: E. Black CHECKED BY: J. Wylie
w
p
U
_
Q J
C�
U)
p
DESCRIPTION
LU
<
Wv
OJ D
mO
a n
WELL
CONSTRUCTION
SC
SAND, tan to gray, medium to coarse sand with fine
sand and silt, few small gravel, moist.
ML
SILT, medium to dark gray, mostly silt, some fine sand,
saturated.
45
SP
SP
ML
SAND, silty, greenish brown (2.5 YR 5/2), little clay,
moist, some roots/or anic matter.
SAND, silty, light yellowish brown )2.5 YR, 6/4), some
cla , moist, low plasticity.
CLAY, silty, yellowish red (5 YR 5/6), moist, medium
lastici
Bentonite seal
Yellowish red (5 YR 5/6) clay with little silt. From
47.4-48 ft. (SAPROLITE)
ML
SILT, loose, strong brown, (7.5 YR 5/6), moist, some
sand.
50
ML
SILT, yellowish brown, (10 YR, 5/8), medium dense,
moist, trace fine sand.
55
—Sand Pack
2" pre-packed well screen
ML
SILT, reddish brown, (5 YR, 5/4), most, trace fine sand,
mottled. (SAPROLITE)
ML
SILT, yellowish brown, (10 YR, 5/8), moist, trace fine
sand, thinly bedded. (SAPROLITE)
60
SM
SAND, brown, (7.5 YR, 5/4), loose, moist, little clay.
(SAPROLITE)
ML
SILT, dense, brown, (7.5 YR, 5/4) moist, fine sand,
iron and manganese staining, infrequent relic texture.
(SAPROLITE)
65
ML
Same as 60.5-65 ft. except dry, more relict structure,
SAPROLITE/PARTIALLY WEATHERED ROCK,
contact at 68 ft.
Borning terminated at 68 ft. Bentonite added to boring
from 61 to 68 ft. to facilitate well construction.
70
75
CLIENT: Duke Energy Progress, LLC.
SynTerra
L� 148 River Street, Suite 220 PROJECT LOCATION: Roxboro, NC
lle, South ling 29601
GreenvsynTerra l864-421-9999
Phone: PAGE 2 OF 2