NC0005363_Revised Coal Pile Assessment Tech Memos_20180606

TECHNICAL MEMORANDUM

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Date: Revised June 1, 2018
Submitted January 12, 2018
File: 1026.17.05J

To: Courtney Murphy (Duke Energy)
Cc: Kathy Webb (SynTerra)
From: Chris Suttell
Subject: Allen Steam Station Coal Pile Assessment Work Plan
Introduction
The initial technical memorandum describing groundwater and soil assessment
activities for the Allen Steam Station (Allen, Plant, or Site) was submitted to the North
Carolina Department of Environmental Quality (NC DEQ) in January 2018. In
correspondence dated May 2, 2018, NC DEQ approved the planned assessment
activities and provided comments to be incorporated. This revised technical
memorandum incorporates the NC DEQ comments (see Table 1 for details of the
comments and responses).
Duke Energy Carolinas, LLC (Duke Energy) owns and operates the Allen Steam Station
(Allen, Plant, or Site) in Belmont, Gaston County, North Carolina. The Site encompasses
approximately 1,009 acres. Groundwater and soil assessment activities proposed for
the coal storage area (coal pile) are described herein.
Regulatory Background
In 2014, The North Carolina General Assembly passed the Coal Ash Management Act
(CAMA). CAMA required owners of a coal combustion residuals (CCR) surface
impoundment to conduct detailed assessment of site groundwater within and around
the CCR surface impoundments.
Primary sources of CCR-related constituents were identified during the Comprehensive
Site Assessment (CSA) for CAMA to be the ash basins, which consists of the active ash
basin and the inactive ash basin. Groundwater monitoring wells were installed south
and west of the coal pile during CAMA-associated fieldwork. Additionally, wells were
installed for compliance with the Environmental Protection Agency’s Coal Combustion
Residuals (CCR) Rule in the vicinity of the coal pile area. Boron, an inorganic
constituent, is commonly used as an indicator of CCR impacts to groundwater.
Groundwater sampling results from the wells near the coal pile did not indicate
Coal Pile Assessment Work Plan Submitted January 12, 2018, Revised June 1, 2018
Duke Energy Carolinas, LLC, Allen Steam Station SynTerra
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elevated concentrations of boron. However, CAMA and CCR assessment data
indicated constituents, such as arsenic, beryllium, cadmium, nickel, selenium, thallium,
and zinc in groundwater samples at concentrations uncharacteristic of other samples
from around the ash basins. For these reasons, Duke Energy understands the coal pile
area soils and underlying groundwater to be a potential additional primary and
“secondary source” of inorganic constituents that will be assessed apart from CAMA or
the CCR Rule.
Station Description
Power generating operations began at Allen in 1957 and the Plant remains active. Coal
used to fuel power generating units is transported to Allen by railroad and is stored on
approximately 18.5 acres south of the power generation plants and north of the ash
basins. CCR have been sluiced to the ash basin system located south of the power
generating units, which includes an active ash basin and the inactive ash basin.
Topography at the site generally slopes downward from the west to the Catawba River
to the east of the Plant and coal pile area.
Currently, a portion of the coal pile is being modified as part of the Allen Steam Station
Water Re-direction Program to allow construction of a lined holding basin on the east
side of the historical coal pile footprint. Part of the construction of the holding basin
includes installation and operation of extraction wells to de-water the area. As of the
date of this memorandum, construction of the dewatering system is complete and the
system is operating at an approximate flowrate of 80 gallons per minute. Eight
observation wells were installed in the vicinity of the holding basin construction project,
and water levels are being recorded on a daily basis. Pressure transducers have also
been installed in wells in close proximity to the coal pile to monitor water level changes
on a more frequent basis.
Coal Pile Area Assessment Objectives
Objectives of the coal pile area assessment include the following:
Characterize inorganic constituents associated with coal pile area soils
Characterize inorganic constituent concentrations in soil and groundwater along
the coal pile perimeter
Compare inorganic constituent concentrations in coal pile area to Site
background concentrations

Coal Pile Assessment Work Plan Submitted January 12, 2018, Revised June 1, 2018
Duke Energy Carolinas, LLC, Allen Steam Station SynTerra
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Soil Assessment
Coal pile area soils will be sampled and analyzed for inorganic parameters to determine
if they are a potential secondary source of CCR-related constituents that can leach into
underlying groundwater. Soil samples will be collected at proposed monitoring well
locations (CP-1 through CP-6) as part of well installation activities (Figure 1). Soil
samples will be collected at approximately 2-foot intervals to the top of the
groundwater table (approximately 10 feet below ground surface). An additional soil
sample will be collected below the water table within the new well screened intervals.
Soil samples will be analyzed for inorganic parameters listed on Table 2.
Groundwater Assessment
Twelve coal pile (CP) assessment groundwater monitoring wells will be installed to
characterize coal pile area groundwater in shallow and deep groundwater zones. The
shallow zone is considered groundwater within soil and saprolite material. The deep
zone is considered groundwater within partially weathered rock transition zone
material underlying the shallow zone and overlying competent bedrock. Six shallow
(“S”) and six deep (“D”) groundwater monitoring wells (CP-1S/D through CP-6S/D)
will be installed as well pairs. Proposed CP well installation locations are shown on
Figure 1 and proposed well details are provided as Table 3. Specific well locations may
be shifted depending upon access and field conditions at the time of installation.
Groundwater samples will be analyzed for inorganic constituents listed on Table 4.
Coal Pile Assessment Report
A coal pile assessment report will be prepared once soil and groundwater sample
analytical data is received. The report will include the following components:
1) Site History and Source Characterization
2) Site Geology and Hydrogeology
3) Sampling Results
4) Site Conceptual Model
5) Conclusions and Recommendations
ATTACHMENTS:
Table 1: Response to NC DEQ Comments - Coal Pile Assessment Work Plan
Table 2: Soil Analytical Methods
Table 3: Proposed Coal Pile Assessment Soil Samples and Monitoring Wells
Table 4: Groundwater Analytical Methods
Figure 1: Proposed Coal Pile Assessment Sample Locations
Coal Pile Assessment Work Plan Submitted January 12, 2018, Revised June 1, 2018
Duke Energy Carolinas, LLC, Allen Steam Station SynTerra

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ATTACHMENTS
TABLE 1
RESPONSE TO NC DEQ COMMENTS - COAL PILE ASSESSMENT WORK PLAN
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC

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The Allen Steam Station Coal Pile Assessment Work Plan Technical Memorandum was
submitted to the North Carolina Department of Environmental Quality (NC DEQ) Division of
Water Resources in January 2018. NC DEQ’s approval of the work plan, with comments on the
submittal, was forwarded to Duke Energy on May 2, 2018. Table 1 (below) includes the NC
DEQ comments with a brief summary response and/or the section(s) of the current submittal
containing a detailed response.
NC DEQ Comment 1
The coal pile assessment report is expected to contain necessary evaluations and
interpretations associated with collected data and not just present the results of the
assessment. This may mean incorporation of groundwater assessment data, coal
combustion residuals (CCR) program data, or any other necessary information needed to
draw appropriate, technically supportable conclusions.
Response Summary
Data will be collected and used in the coal pile assessment report to achieve the
objectives of characterizing inorganic constituents in coal pile area soils and
groundwater, including comparison with site background concentrations. As suggested,
this may include CAMA and CCR program data and other available and relevant data
associated with improvement projects in the vicinity of the coal pile.
NC DEQ Comment 2
The following information shall be presented as part of an evaluation of the hydraulic
effect of the dewatering system in the vicinity of the coal pile before and after operations
commenced:
 A groundwater elevation map prior to operation of the dewatering system,
 A groundwater elevation map for initial start-up (or as close to it as possible),
 A groundwater elevation map under existing conditions as part of the coal pile
assessment, and
 A comparison of data collected as part of the coal pile assessment to groundwater
assessment and/or CCR data as well as data collected as part of the permitting
process for the dewatering system such as aquifer testing, etc.
Response Summary
The hydraulic effect of the dewatering system will be evaluated, including presentation
of the information as suggested. Data from transducers installed in existing wells in the
vicinity of the coal pile will help support this evaluation.
NC DEQ Comment 3
The following technical direction shall be incorporated into the coal pile assessment:
 It was stated in the Coal Pile Assessment Work Plan that Duke would “Compare
Table 1 - Response to NC DEQ Comments - Coal Pile Assessment Work Plan June 1, 2018
Duke Energy Carolinas, LLC, Allen Steam Station SynTerra
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inorganic constituent concentrations in coal pile area to Site background concentrations.”
Analytical results from wells located downgradient of the ash basin shall also be
used for comparison.
• There have been constituents observed at the GWA-6 well cluster that are likely
attributable to other activities at the Site, which should be considered as part of
this assessment since the well is situated between the coal pile and the inactive
ash basin.
• Ensure that when analyzing soil samples for constituents identified in Table 1
[now Table 2], the reporting limit is not above the North Carolina Division of
Waste Management’s Inactive Hazardous Sites Branch Protection of Groundwater
value for that constituent.
• Hexavalent chromium shall be added as a parameter for analysis as part of the
coal pile assessment in Table 3 [now Table 4].
• Groundwater samples from locations CP-2S/D, CP-4S/D, and CP-6S/D shall be
analyzed for total uranium, radium 226, and radium 228.
• Samples from locations CP-2S/D, CP-4S/D, and CP-6S/D shall be collected at
appropriate depths and analyzed for leachable inorganics suing Synthetic
Precipitation Leaching Procedures.
Response Summary
• In addition to analytical results being compared with background values,
analytical results from wells located downgradient of the ash basins will also be
compared with results from the wells downgradient of the coal pile to determine
whether there are notable differences in groundwater quality downgradient of the
different source areas.
• Constituents observed at the GWA-6 well cluster are included in Table 4
(formerly Table 3), which has been updated to be consistent with ongoing IMP
sampling parameters. Results from GWA-6 will be considered as part of the coal
pile assessment to evaluate the potential source(s) of constituents in groundwater
in the vicinity of this well cluster.
• Coal pile assessment soil samples will be analyzed using laboratory reporting
limits at or less than those outlined by the North Carolina Division of Waste
Management’s Inactive Hazardous Sites Branch for Protection of Groundwater.
• Hexavalent chromium will be added as a parameter for analysis as part of the coal
pile assessment. Table 4 (formerly Table 3) of the work plan technical memorandum
has been updated accordingly.
• Groundwater samples from locations CP-2S/D, CP-4S/D, and CP-6S/D will be
analyzed for total uranium, radium-226, and radium-228. The analytical methods for
these analytes are included in Table 4 (formerly Table 3).
• Soil samples from locations CP-2S/D, CP-4S/D, and CP-6S/D will be analyzed for
leachable inorganics using Synthetic Precipitation Leaching Procedures.
Table 1 - Response to NC DEQ Comments - Coal Pile Assessment Work Plan June 1, 2018
Duke Energy Carolinas, LLC, Allen Steam Station SynTerra
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NC DEQ Comment 4
The following revisions to the coal pile assessment plan are recommended:
• While sonic drilling has been recommended as the method of installation for the
coal pile assessment wells, using sonic drilling for the deeper boreholes may
result in complications, therefore, it is recommended traditional drilling methods
(i.e., auger, air, etc.) be employed for wells completed in bedrock or partially
weathered rock. If sonic drilling is chosen, Duke Energy must ensure that the
borehole is properly flushed to remove drilling fluid/cuttings prior to installation
of the monitoring well to reduce the likelihood of sediment accumulation in the
monitoring well which will cause water quality issues and potentially make
development/sampling difficult. These potential complications may result in
installation of replacement wells.
• Proposed well construction involves submerging well screens below the water
table. It is recommended that for shallow wells the screen should not be
submerged (intentionally), but should bracket the water table and if necessary
extend the screen interval to 15-ft to allow the shallow well to accommodate
water table fluctuations.
• CP-1S/D is proposed in a parking/staging area of the site. It is recommended that
this well be moved further south in the grassy area (see attached map).
Positioning a well in a parking/storage area can be problematic for locating the
well and make sampling the well more difficult due to activities in the
parking/storage area.
• It is recommended CP-6S/D be moved further south and install the well
upgradient of the S-9 location to have a better understanding of groundwater
quality and aid in evaluation of whether the coal pile is contributing to impacts
observed at S-9. Also, it is recommended to adjust CP-5S/D a little further south to
compensate for moving CP-6S/D (See attached map).
Response Summary
• Sonic drilling remains SynTerra’s recommended drilling method for the coal pile
assessment. SynTerra provided rationale for the use of sonic drilling techniques in
the 2014 CSA Work Plans for the Duke Energy Progress sites. The rationale
highlighted the advantages of sonic drilling. Compared with other drilling
methods capable of achieving targeted well depths, which includes drilling into
partially weathered rock/transition zone, sonic drilling:
o Produces continuous cores of unconsolidated and consolidated material
with high recovery percentage that can be used for soil sampling and for
observation to determine appropriate depth intervals for well
construction.
o Minimizes formation compaction, borehole disturbance, and smearing
through the use of vibration and slow rotation rates, which minimize the
skin friction on the outer walls of the tooling.
Table 1 - Response to NC DEQ Comments - Coal Pile Assessment Work Plan June 1, 2018
Duke Energy Carolinas, LLC, Allen Steam Station SynTerra
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o Improves well construction reliability as well materials are installed
within the outer steel casing as it is withdrawn and sonic vibration
eliminates the potential for sand bridging.
o Requires less drilling fluids, and the fluids are potable water rather than
mud slurry. This minimizes the amount drilling fluids and sediment that
must be removed later in the well development process.
After installation, the boreholes will be properly flushed/developed to remove
fluids and cuttings prior to the installation of the monitoring wells. As
recommended by NC DEQ during a meeting on May 18, 2018, Duke/SynTerra
will consult closely with drillers to use appropriately sized filter packs and
screens. Centralizers will be used in wells to ensure uniform annulus space for the
filter packs.
• The approach for well screen intervals was outlined in the May 18, 2018 meeting
“Items to Discuss” agenda and in an email from Duke Energy (J. Toepfer) to
NCDEQ (S. Lanter). NCDEQ responded via email (S. Lanter to J. Toepfer) on
May 23, 2018, stating “During the May 18, 2018 teleconference concerning Coal Pile
Assessment Plans, Duke Energy requested concurrence concerning the proposed technical
approach for installing well screens approximately 5 feet below the water table. Based on
the supporting rationale presented during the meeting, the Division agrees with the
proposed plans for well construction to support the assessment. However, the Division
may expect news wells for other scopes of work to have screened intervals installed to
bracket the water table.”
• CP-1S/D, CP-5S/D, and CP-6S/D have been moved accordingly as shown on the
revised work plan Figure 1. Well locations will be appropriately vetted in the
field with input from NC DEQ based on access, utilities, and other potential
impacts.

TABLE 2
SOIL ANALYTICAL METHODS
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
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Table 2 - Soil Analytical Methods.xlsx Page 1 of 1
INORGANIC COMPOUNDS UNITS METHOD
Aluminum mg/kg EPA 6010D
Antimony mg/kg EPA 6020B
Arsenic mg/kg EPA 6020A
Barium mg/kg EPA 6010C
Beryllium mg/kg EPA 6020B
Boron mg/kg EPA 6010C
Cadmium mg/kg EPA 6020A
Calcium mg/kg EPA 6010C
Chloride mg/kg EPA 9056A
Chromium mg/kg EPA 6010C
Cobalt mg/kg EPA 6020A
Copper mg/kg EPA 6010C
Iron mg/kg EPA 6010C
Lead mg/kg EPA 6020A
Magnesium mg/kg EPA 6010C
Manganese mg/kg EPA 6010C
Mercury mg/kg EPA Method 7471B
Molybdenum mg/kg EPA 6010C
Nickel mg/kg EPA 6010C
Nitrate as Nitrogen mg/kg EPA 9056A
pH SU EPA 9045D
Potassium mg/kg EPA 6010C
Selenium mg/kg EPA 6020A
Sodium mg/kg EPA 6010C
Strontium mg/kg EPA 6010C
Sulfate mg/kg EPA 9056A
Thallium (low level) (SPLP Extract only)mg/kg EPA 6020A
Total Organic Carbon mg/kg EPA 9060
Vanadium mg/kg EPA 6020A
Zinc mg/kg EPA 6010C
Notes:
1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045, as noted above.
meq/100g - millequivalents per 100 grams
mg/kg - Milligrams per kilogram
mV - Millivolts
S.U. - Standard Unit
Prepared by: RBI Checked by: CJS
2. Ash samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045; select ash
samples will also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with USEPA Methods 6010/6020.
3. Analytical methods and reporting limits as presented were applicable at time of CSA field implementation in 2015. Analytical methods
and reporting limits are updated periodically and applied as appropriate.
TABLE 3
PROPOSED COAL PILE ASSESSMENT SOIL SAMPLES AND MONITORING WELLS
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
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Table 3 - Allen Proposed Coal Pile Assessment Boring & Well Depths.xlsx Page 1 of 1
Monitoring
Well ID
Estimated
Well Depth
(feet bgs)
Soil Sample ID
(Estimated Depth
Interval in feet bgs)
Comments
----CP-1SB (2-3)Near-surface unsaturated soil sample, water table ~10 feet bgs
----CP-1SB (5-6)Unsaturated soil sample, water table ~10 feet bgs
----CP-1SB (8-9)Unsaturated soil sample, water table ~10 feet bgs
CP-1S 30 CP-1SB (25-26)Soil sample from shallow well screened interval
CP-1D 140 CP-1SB (135-136)Soil sample from deep well screened interval
----CP-2SB (2-3)Near-surface unsaturated soil sample, water table ~10 feet bgs
----CP-2SB (5-6)Unsaturated soil sample, water table ~10 feet bgs
----CP-2SB (8-9)Unsaturated soil sample, water table ~10 feet bgs
CP-2S 30 CP-2SB (27-28)Soil sample from shallow well screened interval
CP-2D 125 CP-2SB (122-123)Soil sample from deep well screened interval
----CP-3SB (2-3)Near-surface unsaturated soil sample, water table ~10 feet bgs
----CP-3SB (5-6)Unsaturated soil sample, water table ~10 feet bgs
----CP-3SB (8-9)Unsaturated soil sample, water table ~10 feet bgs
CP-3S 25 CP-3SB (22-23)Soil sample from shallow well screened interval
CP-3D 115 CP-3SB (112-113)Soil sample from deep well screened interval
----CP-4SB (2-3)Near-surface unsaturated soil sample, water table ~10 feet bgs
----CP-4SB (5-6)Unsaturated soil sample, water table ~10 feet bgs
----CP-4SB (8-9)Unsaturated soil sample, water table ~10 feet bgs
CP-4S 25 CP-4SB (22-23)Soil sample from shallow well screened interval
CP-4D 115 CP-4SB (112-113)Soil sample from deep well screened interval
----CP-5SB (2-3)Near-surface unsaturated soil sample, water table ~10 feet bgs
----CP-5SB (5-6)Unsaturated soil sample, water table ~10 feet bgs
----CP-5SB (8-9)Unsaturated soil sample, water table ~10 feet bgs
CP-5S 25 CP-5SB (22-23)Soil sample from shallow well screened interval
CP-5D 115 CP-5SB (112-113)Soil sample from deep well screened interval
----CP-6SB (2-3)Near-surface unsaturated soil sample, water table ~10 feet bgs
----CP-6SB (5-6)Unsaturated soil sample, water table ~10 feet bgs
----CP-6SB (8-9)Unsaturated soil sample, water table ~10 feet bgs
CP-6S 25 CP-6SB (22-23)Soil sample from shallow well screened interval
CP-6D 115 CP-6SB (112-113)Soil sample from deep well screened interval
Prepared by: LWD Checked by: CJS
Notes:
bgs = below ground surface
~ = Approximately
SynTerra recommends rotosonic drilling methods for boring and well installation
Continuous cores from sonic drilling provide sufficient material for soil sampling and lithologic description.
Estimated well and soil sample depths based on data from the GWA-4, GWA-5 and GWA-7 well clusters.
SynTerra recommends each well screen be submerged beneath the water table and have a length of at least 10 feet
SynTerra proposes soil samples be collected from well screen intervals for potential use in MNA analysis.
Number of soil samples shown is approximate. A shallower water table will result in fewer samples, and a deeper water table will result in additional
samples.
TABLE 4
GROUNDWATER ANALYTICAL METHODS
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
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Table 4 - Groundwater Analytical Methods.xlsx Page 1 of 1
PARAMETER RL UNITS METHOD
pH NA SU Field Water Quality Meter
Specific Conductance NA µS/cm Field Water Quality Meter
Temperature NA ºC Field Water Quality Meter
Dissolved Oxygen NA mg/L Field Water Quality Meter
Oxidation Reduction Potential NA mV Field Water Quality Meter
Eh NA mV Field Water Quality Meter
Turbidity NA NTU Field Water Quality Meter
Aluminum 0.005 mg/L EPA 200.7 or 6010D
Antimony 0.001 mg/L EPA 200.8 or 6020B
Arsenic 0.001 mg/L EPA 200.8 or 6020B
Barium 0.005 mg/L EPA 200.7 or 6010D
Beryllium 0.001 mg/L EPA 200.8 or 6020B
Boron 0.05 mg/L EPA 200.7 or 6010D
Cadmium 0.001 mg/L EPA 200.8 or 6020B
Chromium 0.001 mg/L EPA 200.8 or 6020B
Cobalt 0.001 mg/L EPA 200.8 or 6020B
Copper 0.001 mg/L EPA 200.8 or 6020B
Hexavalent Chromium 0.000025 mg/L EPA 218.7
Iron 0.01 mg/L EPA 200.7 or 6010D
Lithium 1 mg/L EPA 200.7 or 6010D
Lead 0.001 mg/L EPA 200.8 or 6020B
Manganese 0.005 mg/L EPA 200.7 or 6010D
Mercury 0.00005 mg/L EPA 245.1 or 7470A
Molybdenum 0.001 mg/L EPA 200.8 or 6020B
Nickel 0.001 mg/L EPA 200.8 or 6020B
Selenium 0.001 mg/L EPA 200.8 or 6020B
Strontium 0.005 mg/L EPA 200.7 or 6010D
Thallium (low level)0.0002 mg/L EPA 200.8 or 6020B
Vanadium (low level)0.0003 mg/L EPA 200.8 or 6020B
Zinc 0.005 mg/L EPA 200.7 or 6010D
Radium 226 1 pCi/L EPA 903.1 Modified
Radium 228 1 pCi/L EPA 904.0/SW846 9320 Modified
Uranium (233, 234, 236, 238)Varies by isotope µg/mL SW846 3010A/6020A
Alkalinity (as CaCO3)5 mg/L SM 2320B
Bicarbonate 5 mg/L SM 2320B
Calcium 0.01 mg/L EPA 200.7
Carbonate 5 mg/L SM 2320B
Chloride 0.1 mg/L EPA 300.0 or 9056A
Fluoride 0.1 mg/L EPA 300.0 or 9056A
Magnesium 0.005 mg/L EPA 200.7 or 6010D
Potassium 0.1 mg/L EPA 200.7
Sodium 0.05 mg/L EPA 200.7
Sulfate 0.1 mg/L EPA 300.0 or 9056A
Sulfide 0.1 mg/L SM 4500 S2 D
Total Dissolved Solids 25 mg/L SM 2540C
Total Phosphorus 0.05 mg/L EPA 365.1
Total Organic Carbon 0.1 mg/L SM5310C/EPA9060A
Total Suspended Solids 5 mg/L SM 2450D
Prepared by: HHS Checked by: RHJ
Notes:
NA indicates not applicable.
°C - Degrees Celsius
mg/L - Milligrams per liter
mV - Millivolts
NTU - Nephelometric turbidity unit
pCi/L - picocuries per liter
RL = reporting limit
S.U. - Standard Unit
ug/mL - micrograms per milliliter
µS/cm = micro-Siemens per centimeter
Dissolved and total metals analysis
FIELD PARAMETERS
INORGANICS
RADIONUCLIDES
ANIONS/CATIONS/OTHER
&<
&<
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&<
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&<
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&<
&<
&<
&<&<&<
&<
&<
&<
&<
&<
&<
&<!(
LAKE WYLIE
ALLEN STEAM STATION
COAL PILE
INA CTIVE A SH BASIN
S-9
GWA-6S/D/DA/BR
GWA-7S/D
AB-33S/D
CP-6S/D
CP-5S/D
CP-4S/D
CP-3S/D
CP-2S/D
CP-1S/D
CCR-9S/D
CCR-8S/DCCR-7S/DCCR-6S/D
CCR-5S/D
CCR-4S/D
600
610
6
2
0 5906
3
0
6406505
8
0
570
6606006 0 0
570
6105906205
8
0
610
5 8 0
590
580580
590
6305906105
8
0
610 6005906
3
0
6205
9
0
6405905905
8
0
610FIG URE 1PROPOSED COAL PILE ASSESSMENTSAMPLE LOCATIONSALLEN STEAM STATIONDUKE ENERGY CAROLINAS, LLCBELMONT, NORTH CAROLINADRAWN BY: K. KINGPROJECT MA NAGER: C. SUTTELLCHECKED BY: L. DRAGO
DATE: 05/24/2018
148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE [phone]www.synterracorp.com
P:\Duke Energy Progress.1026\00 GIS BASE DATA\Allen\Map_Docs\MISC\ALLEN_PropCoalPile_AssessmentWells05242018.mxd
80 0 80 16040
GRAPHIC SCA LE IN FEET
NOTES:
PROPOSED WELL AND BORING LOCATIONS ARE APPROXIMATEAND MAY BE ADJUSTED BASED ON ACCESSIBILITY AND FIELDCONDITIONS.
2014 AERIAL ORTHOPHOTOGRAPHY OBTAINED FROM W SP, APRIL2014.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTHCAROLINA STATE PLANE COORDINATE SYSTEM FIPS 3200(NAD83/2011).
LEGEND
&<PROPOSED COAL PILE ASSESSMENT SOILBORING AND MONITORING W ELL
&<EXISTING CCR RULE MONITORING W ELLLOCATION (APPROXIMATE)
&<EXISTING CAMA GROUNDW ATERMONITORING WELL LOCATION
!(AOW AND SEDIMENT SAMPLE LOCATION
APPROXIMATE EXTENT OF COAL PILESTORAGE AREA
WASTE BOUNDARY
DUKE ENERGY PLANT BOUNDARY
TOPOGRAPHIC CONTOURS (10' INTERVAL)
TOPOGRAPHIC CONTOURS (2' INTERVAL)
TECHNICAL MEMORANDUM

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Revision May 2018\Coal Pile Assessment Tech Memo Revised.docx
Date: Revised June 1, 2018
Submitted January 12, 2018
File: 1026.15.05I

To: Bristol Grohol (Duke Energy)
Cc: Kathy Webb (SynTerra)
From: Judd Mahan
Subject: Soil and Groundwater Assessment – Former Coal Pile – Riverbend Steam Station
Introduction
The initial technical memorandum describing groundwater and soil assessment
activities for the Riverbend Steam Station (RBSS or Site) was submitted to the North
Carolina Department of Environmental Quality (NC DEQ) in January 2018. In
correspondence dated May 4, 2018, NC DEQ approved the planned assessment
activities and provided comments to be incorporated. This revised technical
memorandum incorporates the NC DEQ comments (see Table 1 for details of the
comments and responses).
Duke Energy Carolinas, LLC (Duke Energy) owns and operated the RBSS in Mount
Holly, NC. The Site encompasses approximately 340.7 acres. RBSS began operation as a
coal-fired generating station in 1929 and was retired in April 2013. Coal used for
electricity generation was transported to the Site by railroad and stored on
approximately 12 acres northeast of the power generation plant. Ash generated by the
coal-fired power-generating units was sluiced to ash management areas located
northeast of the plant operations. Groundwater and soil assessment activities for the
former coal storage area (coal pile) are described herein.
Regulatory Background
In 2014, The North Carolina General Assembly passed the Coal Ash Management Act
(CAMA). CAMA required owners of a coal combustion residuals (CCR) surface
impoundment to conduct detailed assessment of site groundwater within and around
the CCR surface impoundment.
Groundwater monitoring wells were installed near the eastern edge of the former coal
pile during CAMA-associated fieldwork. Boron, an inorganic constituent, is commonly
used as an indicator of CCR impacts to groundwater. Groundwater sampling results
from the wells near the former coal pile did not indicate elevated concentrations of
boron. However, the data indicated beryllium in groundwater samples at
Soil and Groundwater Assessment – Former Coal Pile Submitted January 12, 2018 Revised June 1, 2018
Duke Energy Carolinas, LLC, Riverbend Steam Station SynTerra
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concentrations uncharacteristic of other samples from around the coal ash management
areas. For these reasons, Duke Energy understands the former coal pile area soils and
underlying groundwater to be a potential “secondary source” of inorganic constituents
that will be assessed apart from CAMA.
Station Description
Coal-fired power generation operations began at RBSS in 1929 and ended in April 2013
when the coal-fired units were retired. Coal was transported on-site by rail and
offloaded onto the coal pile area where it was stored until burned by the coal-powered
energy generating units. The former coal pile area is approximately 12 acres and is
located adjacent to the RBSS power house building and the Catawba River. Coal
removal from the area was completed in September 2014. Commingled coal and soil
material removal was completed in December 2016. A visual inspection was performed
to verify commingled coal and soil material was removed.
The topography at RBSS generally slopes downward from the south to the Catawba
River on the north. The site layout is shown on Figure 1.
Coal Pile Area Assessment Objectives
Objectives of the coal pile area assessment include the following:
Characterize inorganic constituents associated with coal pile area soils
Characterize inorganic constituent concentrations in shallow groundwater
underlying the coal pile area and along the coal pile area perimeter
Compare inorganic constituent concentrations in coal pile area groundwater and
site background groundwater
Soil Assessment
Coal pile area soils will be sampled and analyzed for inorganic parameters to determine
if they are a secondary source of coal pile constituents that can leach into underlying
groundwater. Soil samples will be collected at proposed monitoring well locations
(CPA-1 through CPA-7) as part of well installation activities. Two proposed sample
locations (CPA-4 and CPA-5) are within the footprint of the former coal pile (Figure 1).
Soil samples will be collected at approximately 2-foot intervals to the top of the
groundwater table. An additional soil sample will be collected below the water table
within the new well screened intervals. Soil samples will be analyzed for inorganic
parameters as listed on Table 2.
In addition to proposed monitoring well locations, this work plan has been modified to
incorporate three soil borings (SB-1 through SB-3) that will be installed by direct push
Soil and Groundwater Assessment – Former Coal Pile Submitted January 12, 2018 Revised June 1, 2018
Duke Energy Carolinas, LLC, Riverbend Steam Station SynTerra
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technology (DPT) in approximate locations as shown on Figure 1. The proposed soil
borings will be installed to total depths dictated by first encounter of either probe
refusal or top of groundwater. Sampling intervals and analyses for these proposed
borings will be consistent with monitoring well soil assessment as described above.
Groundwater Assessment
Fourteen coal pile assessment (CPA) groundwater monitoring wells will be installed to
characterize coal pile area groundwater. Seven shallow (“S”) and seven deep (“D”)
groundwater monitoring wells (CPA-1S/D, CPA-2S/D, CPA-3S/D, CPA-4S/D, CPA-
5S/D, CPA-6S/D, and CPA-7S/D) will be installed as well pairs. Four wells (CPA-4S/D
and CPA-5S/D) will be installed within the former coal pile footprint. Proposed
approximate CPA well installation locations are shown on Figure 1 and proposed well
details are provided as Table 3. Specific well locations may be shifted depending upon
access and field conditions at the time of installation. Groundwater samples will be
analyzed for inorganic constituents as listed on Table 4.
Coal Pile Assessment Report
A coal pile assessment report will be prepared once all soil and groundwater sample
analytical data is received. The report will include the following components:
1) Site History and Source Characterization
2) Site Geology and Hydrogeology
3) Sampling Results
4) Site Conceptual Model
5) Conclusions and Recommendations
ATTACHMENTS:
Table 1: Response to NC DEQ Comments – Coal Pile Assessment Work Plan
Table 2: Soil Analytical Methods
Table 3: Proposed Coal Pile Assessment Soil Samples and Monitoring Wells
Table 4: Groundwater Analytical Methods
Figure 1: Proposed Monitoring Well Locations
Soil and Groundwater Assessment – Former Coal Pile Submitted January 12, 2018 Revised June 1, 2018
Duke Energy Carolinas, LLC, Riverbend Steam Station SynTerra

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ATTACHMENTS

TABLE 1
RESPONSE TO NC DEQ COMMENTS – COAL PILE ASSESSMENT WORK PLAN
RIVERBEND STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOUNT HOLLY, NC

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The Riverbend Steam Station Coal Pile Assessment Work Plan Technical Memorandum was submitted
to the North Carolina Department of Environmental Quality Division of Water Resources (Division) in
January 2018. NCDEQ approval of the work plan with comments on the submittal was forwarded to
Duke Energy on May 04, 2018. The table below includes the NCDEQ comments with a brief summary
response and/or the section(s) of the current submittal containing a detailed response.
DEQ Comment 1
The coal pile assessment report is expected to contain necessary evaluation and interpretation
associated with data collected and not just a presentation of the results of the assessment in a
data summary format. This may mean incorporation of groundwater assessment data, coal
combustion residuals (CCR) program data, or any other necessary information needed to draw
appropriate, technically supportable conclusions.
Response Summary
The Coal Pile Assessment Report will utilize data collected to achieve the objectives of
characterizing inorganic constituents in coal pile area soils and shallow groundwater including
comparison with site background concentrations. As suggested, this may include groundwater
assessment data and CCR program data collected as part of other assessments at the site.
DEQ Comment 2
To assess the vertical extent of impacts in the shallow aquifer, the Division recommends
screening the paired deeper wells at an interval of 50-60 feet for this phase.
Response Summary
As discussed in the conference call between Duke Energy, DEQ, and SynTerra on May 18,
2018, the deeper well at each well pair is intended to monitor the saturated zone of overburden
above competent bedrock. Careful observation of core collected at each well pair location, and
professional judgement to determine the zone of potential relative high conductivity located
above competent bedrock (transition zone) will be used to determine screened intervals.
Review of boring logs for nearby existing wells (GWA-3D, GWA-11D, and GWA-12D) indicates
that strong to very strong, meta-quartz diorite occurs at depths ranging from 40 to 122 feet.
Potential screened intervals for the current assessment are likely to be located at or just above
those depths.
DEQ Comment 3
Move wells CPA-1S/D, CPA-2S/D, CPA,-3S/D, CPA-6S/D, and CPA-7S/D to the known perimeter
of the former coal pile footprint.
Response Summary
As discussed in the conference call between DEQ, Duke Energy, and SynTerra on May 18,
2018, the distance between the perimeter of the former coal pile footprint and the Catawba
River is very limited (approximately 200 feet in several locations). The available locations for
monitoring wells are also constrained by steep terrain and wetlands. Therefore as agreed
during the call, additional soil borings SB-1 through SB-3 will be added to assess soil at an
intermediate distance, and the original proposed well locations will be used for monitoring well
installations (see Figure 1).
DEQ Comment 4
Install an additional downgradient monitoring well pair between the northern edge of the
former coal pile area (between proposed wells CPA-1S/D and CPA-2S/D) and the Catawba
River.

Table 1 - Response to NC DEQ Comments – Coal Pile Assessment Work Plan June 1, 2018
Duke Energy Carolinas, LLC, Riverbend Steam Station SynTerra
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Response Summary
As noted in the response for Comment 3, the distance between the former coal pile footprint
and the Catawba River is limited and locations available for well installation are constrained by
steep topography and wetlands. Additional soil borings SB-1 through SB-3 have been added to
address assessment between the coal pile footprint and the downgradient area (see Figure 1).
DEQ Comment 5
Samples for radionuclide analysis (Radium 226 and 228 and Total Uranium) shall be collected
from the soil and groundwater in the proposed wells and additional well requested above. For
soil, one sample per well pair is sufficient. For groundwater, one groundwater sample shall be
collected in each well.
Response Summary
Radionuclide data will be collected for characterization of shallow groundwater. NCDEQ
provided concurrence on May 31, 2018 that soil samples for radionuclide data do not need to
be taken because there is no background data available for comparison. An email from NCDEQ
(S. Lanter) to Duke (B. Grohol) was received on May 31, 2018 acknowledging that "Removal of
soil analysis for radionuclides as part of the plans supersedes previous direction given by
Division for the Riverbend and Weatherspoon facility Coal Pile Assessment Plan comment
letters both dated May 4, 2018."
DEQ Comment 6
While sonic drilling has been recommended as the method of installation for the coal pile
assessment wells, using sonic drilling for the deeper boreholes may result in complications,
therefore, it is recommended traditional drilling methods (i.e., auger, air, etc.) be employed for
wells completed in bedrock or partially weathered rock. If sonic drilling is chosen, Duke Energy
must ensure that the borehole is properly flushed to remove drilling fluid/cuttings prior to
installation of the monitoring well to reduce the likelihood of sediment accumulation in the
monitoring well which will cause water quality issues and potentially make
development/sampling difficult. These potential complications may result in installation of
replacement wells.
Response Summary
Sonic drilling remains SynTerra’s recommended drilling method for the coal pile assessment.
SynTerra provided rationale for the use of sonic drilling techniques in the 2014 CSA Work Plans
for the Duke Energy Progress sites. The rationale highlighted the advantages of sonic drilling.
Compared to other drilling methods capable of achieving targeted well depths, which includes
drilling into partially weathered rock/transition zone, sonic drilling:
• Produces continuous cores of unconsolidated and consolidated material with high recovery
percentage that can be utilized for soil sampling and for observation to determine
appropriate depth intervals for well construction.
• Minimizes formation compaction, borehole disturbance and smearing through the use of
vibration and slow rotation rates which minimize the skin friction on the outer walls of the
tooling.
• Improves well construction reliability as well materials are installed within the outer steel
casing as it is withdrawn and sonic vibration eliminates the potential for sand bridging.
• Requires less drilling fluids, and the fluids are potable water rather than mud slurry. This
minimizes the amount drilling fluids and sediment that need to be removed later in the well
development process.
After installation, the boreholes will be properly flushed/developed to remove fluids and
cuttings prior to the installation of the monitoring wells. As recommended by NCDEQ,
Duke/SynTerra will consult closely with drillers to use appropriately-sized filter packs and
screens. Centralizers will be used in wells to ensure uniform annulus space for the filter packs.

Table 1 - Response to NC DEQ Comments – Coal Pile Assessment Work Plan June 1, 2018
Duke Energy Carolinas, LLC, Riverbend Steam Station SynTerra
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DEQ Comment 7
Proposed well construction involves submerging well screens below the water table. It is
recommended that for shallow wells the screen should not be submerged (intentionally), but
should bracket the water table and if necessary extend the screen interval to 15-ft to allow the
shallow well to accommodate water table fluctuations.
Response Summary
The approach for well screen intervals was outlined in a May 18, 2018 email from Duke Energy (J.
Toepfer) to NCDEQ (S. Lanter). NCDEQ responded via email (S. Lanter to J. Toepfer) on May 23, 2018,
stating “During the May 18, 2018 teleconference concerning Coal Pile Assessment Plans, Duke Energy
requested concurrence concerning the proposed technical approach for installing well screens
approximately 5 feet below the water table. Based on the supporting rationale presented during the
meeting, the Division agrees with the proposed plans for well construction to support the
assessment. However, the Division may expect new wells for other scopes of work to have screened
intervals installed to bracket the water table.”

TABLE 2
SOIL ANALYTICAL METHODS
RIVERBEND STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOUNT HOLLY, NC
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Table 2 Soil Analytical Methods.xlsx Page 1 of 1
INORGANIC COMPOUNDS UNITS METHOD
Aluminum mg/kg EPA 6010D
Antimony mg/kg EPA 6020B
Arsenic mg/kg EPA 6020B
Barium mg/kg EPA 6010D
Beryllium mg/kg EPA 6010D
Boron mg/kg EPA 6010D
Cadmium mg/kg EPA 6020B
Calcium mg/kg EPA 6010D
Chloride mg/kg EPA 9056A
Chromium mg/kg EPA 6010C
Cobalt mg/kg EPA 6020A
Copper mg/kg EPA 6010C
Iron mg/kg EPA 6010C
Lead mg/kg EPA 6020B
Magnesium mg/kg EPA 6010D
Manganese mg/kg EPA 6010C
Mercury mg/kg EPA 7471 B
Molybdenum mg/kg EPA 6010D
Nickel mg/kg EPA 6010C
Nitrate as Nitrogen mg/kg EPA 9056A
pH SU EPA 9045D
Potassium mg/kg EPA 6010D
Selenium mg/kg EPA 6020B
Sodium mg/kg EPA 6010D
Strontium mg/kg EPA 6010D
Sulfate mg/kg EPA 9056A
Thallium (total, low level)mg/kg EPA 6020B
Total Organic Carbon mg/kg EPA 9060
Vanadium mg/kg EPA 6020B
Zinc mg/kg EPA 6010C
Notes:
1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045, as noted above.
meq/100g - millequivalents per 100 grams
mg/kg - Milligrams per kilogram
mV - Millivolts
S.U. - Standard Unit
Prepared by: RBI Checked by: WJW
2. Ash samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045; select ash
samples will also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with USEPA Methods 6010/6020.
3. Analytical methods and reporting limits as presented were applicable at time of CSA field implementation in 2015. Analytical methods
and reporting limits are updated periodically and applied as appropriate.
TABLE 3
PROPOSED COAL PILE ASSESSMENT SOIL SAMPLES AND MONITORING WELLS
RIVERBEND STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOUNT HOLLY, NC
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Assessment Boring & Well Depths.xlsx Page 1 of 2
Monitoring
Well/Soil
Boring ID
Estimated
Well Depth
(feet bgs)
Soil Sample ID
(Estimated Depth
Interval in feet bgs)
Comments
----CPA-1SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-1SB (5-6)Unsaturated soil sample
----CPA-1SB (8-9)Unsaturated soil sample
----CPA-1SB (11-12)Unsaturated soil sample
----CPA-1SB (14-15)Unsaturated soil sample
----CPA-1SB (17-18)Unsaturated soil sample
----CPA-1SB (20-21)Unsaturated soil sample
----CPA-1SB (23-24)Unsaturated soil sample
CPA-1S 35 CPA-1SB (30-31)Soil sample from shallow well screened interval
CPA-1D 150 CPA-1SB (145-146)Soil sample from deep well screened interval
----CPA-2SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-2SB (5-6)Unsaturated soil sample
----CPA-2SB (8-9)Unsaturated soil sample
----CPA-2SB (11-12)Unsaturated soil sample
----CPA-2SB (14-15)Unsaturated soil sample
----CPA-2SB (17-18)Unsaturated soil sample
----CPA-2SB (20-21)Unsaturated soil sample
----CPA-2SB (23-24)Unsaturated soil sample
CPA-2S 35 CPA-2SB (30-31)Soil sample from shallow well screened interval
CPA-2D 150 CPA-2SB (145-146)Soil sample from deep well screened interval
----CPA-3SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-3SB (5-6)Unsaturated soil sample
----CPA-3SB (8-9)Unsaturated soil sample
----CPA-3SB (11-12)Unsaturated soil sample
----CPA-3SB (14-15)Unsaturated soil sample
----CPA-3SB (17-18)Unsaturated soil sample
----CPA-3SB (20-21)Unsaturated soil sample
----CPA-3SB (23-24)Unsaturated soil sample
CPA-3S 35 CPA-3SB (30-31)Soil sample from shallow well screened interval
CPA-3D 150 CPA-3SB (145-146)Soil sample from deep well screened interval
----CPA-4SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-4SB (5-6)Unsaturated soil sample
----CPA-4SB (8-9)Unsaturated soil sample
----CPA-4SB (11-12)Unsaturated soil sample
----CPA-4SB (14-15)Unsaturated soil sample
----CPA-4SB (17-18)Unsaturated soil sample
----CPA-4SB (20-21)Unsaturated soil sample
----CPA-4SB (23-24)Unsaturated soil sample
CPA-4S 35 CPA-4SB (30-31)Soil sample from shallow well screened interval
CPA-4D 150 CPA-4SB (145-146)Soil sample from deep well screened interval
----CPA-5SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-5SB (5-6)Unsaturated soil sample
----CPA-5SB (8-9)Unsaturated soil sample
----CPA-5SB (11-12)Unsaturated soil sample
----CPA-5SB (14-15)Unsaturated soil sample
----CPA-5SB (17-18)Unsaturated soil sample
----CPA-5SB (20-21)Unsaturated soil sample
----CPA-5SB (23-24)Unsaturated soil sample
CPA-5S 35 CPA-5SB (30-31)Soil sample from shallow well screened interval
CPA-5D 150 CPA-5SB (145-146)Soil sample from deep well screened interval
TABLE 3
PROPOSED COAL PILE ASSESSMENT SOIL SAMPLES AND MONITORING WELLS
RIVERBEND STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOUNT HOLLY, NC
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Assessment Boring & Well Depths.xlsx Page 2 of 2
Monitoring
Well/Soil
Boring ID
Estimated
Well Depth
(feet bgs)
Soil Sample ID
(Estimated Depth
Interval in feet bgs)
Comments
----CPA-6SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-6SB (5-6)Unsaturated soil sample
----CPA-6SB (8-9)Unsaturated soil sample
----CPA-6SB (11-12)Unsaturated soil sample
----CPA-6SB (14-15)Unsaturated soil sample
----CPA-6SB (17-18)Unsaturated soil sample
----CPA-6SB (20-21)Unsaturated soil sample
----CPA-6SB (23-24)Unsaturated soil sample
CPA-6S 35 CPA-6SB (30-31)Soil sample from shallow well screened interval
CPA-6D 150 CPA-6SB (145-146)Soil sample from deep well screened interval
----CPA-7SB (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
----CPA-7SB (5-6)Unsaturated soil sample
----CPA-7SB (8-9)Unsaturated soil sample
----CPA-7SB (11-12)Unsaturated soil sample
----CPA-7SB (14-15)Unsaturated soil sample
----CPA-7SB (17-18)Unsaturated soil sample
----CPA-7SB (20-21)Unsaturated soil sample
----CPA-7SB (23-24)Unsaturated soil sample
CPA-7S 35 CPA-7SB (30-31)Soil sample from shallow well screened interval
CPA-7D 150 CPA-7SB (145-146)Soil sample from deep well screened interval
--SB-1 (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
--SB-1 (5-6)Unsaturated soil sample
--SB-1 (8-9)Unsaturated soil sample
--SB-1 (11-12)Unsaturated soil sample
--SB-1 (14-15)Unsaturated soil sample
--SB-1 (17-18)Unsaturated soil sample
--SB-1 (20-21)Unsaturated soil sample
--SB-1 (23-24)Unsaturated soil sample
--SB-2 (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
--SB-2 (5-6)Unsaturated soil sample
--SB-2 (8-9)Unsaturated soil sample
--SB-2 (11-12)Unsaturated soil sample
--SB-2 (14-15)Unsaturated soil sample
--SB-2 (17-18)Unsaturated soil sample
--SB-2 (20-21)Unsaturated soil sample
--SB-2 (23-24)Unsaturated soil sample
--SB-3 (2-3)
Near-surface unsaturated soil sample (water table ~25 feet
bgs)
--SB-3 (5-6)Unsaturated soil sample
--SB-3 (8-9)Unsaturated soil sample
--SB-3 (11-12)Unsaturated soil sample
--SB-3 (14-15)Unsaturated soil sample
--SB-3 (17-18)Unsaturated soil sample
--SB-3 (20-21)Unsaturated soil sample
--SB-3 (23-24)Unsaturated soil sample
Prepared by: JDM Checked by: WJW
Notes:
bgs = below ground surface
~ = Approximately
SynTerra recommends rotosonic drilling methods for boring and well installation.
Continuous cores from sonic drilling provide sufficient material for soil sampling and lithologic description.
Estimated well and soil sample depths based on data from the GWA-3, GWA-11 and GWA-12 well clusters.
Number of soil samples shown is approximate. A shallower water table will result in fewer samples, and a deeper water table will result in additional samples.
SynTerra recommends each well screen be submerged beneath the water table and have a length of at least 10 feet.
SB-3
SB-1
SB-2
TABLE 4
GROUNDWATER ANALYTICAL METHODS
RIVERBEND STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOUNT HOLLY, NC
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PARAMETER RL UNITS METHOD
pH NA SU Field Water Quality Meter
Specific Conductance NA µS/cm Field Water Quality Meter
Temperature NA ºC Field Water Quality Meter
Dissolved Oxygen NA mg/L Field Water Quality Meter
Oxidation Reduction Potential NA mV Field Water Quality Meter
Turbidity NA NTU Field Water Quality Meter
Ferrous Iron NA mg/L Field Test Kit
Aluminum 0.005 mg/L EPA 200.7 or 6010D
Antimony 0.001 mg/L EPA 200.8 or 6020B
Arsenic 0.001 mg/L EPA 200.8 or 6020A
Barium 0.005 mg/L EPA 200.7 or 6010C
Beryllium 0.001 mg/L EPA 200.8 or 6020A
Boron 0.05 mg/L EPA 200.7 or 6010C
Cadmium 0.001 mg/L EPA 200.8 or 6020A
Chromium 0.001 mg/L EPA 200.8 or 6010C
Cobalt 0.001 mg/L EPA 200.8 or 6020A
Copper 0.001 mg/L EPA 200.8 or 6020B
Iron 0.01 mg/L EPA 200.7 or 6010C
Lead 0.001 mg/L EPA 200.8 or 6020A
Manganese 0.005 mg/L EPA 200.7 or 6010C
Mercury (low level)0.005 ng/L 1631 ONLY
Molybdenum 0.001 mg/L EPA 200.8 or 6020B
Nickel 0.001 mg/L EPA 200.8 or 6020B
Phosphorus 0.005 mg/L EPA 365.1
Selenium 0.001 mg/L EPA 200.8 or 6020A
Strontium 0.005 mg/L EPA 200.7 or 6010C
Thallium (low level)0.0002 mg/L EPA 200.8 or 6020A
Vanadium (low level)0.0003 mg/L EPA 200.8 or 6020A
Zinc 0.005 mg/L EPA 200.7 or 6010C
Radium 226 1 pCi/L EPA 903.1 Modified
Radium 228 1 pCi/L EPA 904.0/SW846 9320 Modified
Uranium (233, 234, 236, 238)Varies by isotope µg/mL SW846 3010A/6020A
Alkalinity (as CaCO3)5 mg/L SM 2320B
Bicarbonate 5 mg/L SM 2320
Calcium 0.01 mg/L EPA 200.7
Carbonate 5 mg/L SM 2320
Chloride 0.1 mg/L EPA 300.0 or 9056A
Magnesium 0.005 mg/L EPA 200.7
Methane 0.01 mg/L RSK 175
Nitrate as Nitrogen 0.01 mg-N/L EPA 353.2
Potassium 0.1 mg/L EPA 200.7
Sodium 0.05 mg/L EPA 200.7
Sulfate 0.1 mg/L EPA 300.0 or 9056A
Sulfide 0.1 mg/L SM4500S2-D
Total Dissolved Solids 25 mg/L SM 2540C
Total Organic Carbon 0.1 mg/L SM 5310C/EPA9060A
Total Suspended Solids 2.5 mg/L SM 2450D
Prepared by: RBI Checked by: WJW
Notes:
ºC - Degrees Celsius
µS/cm = micro-Siemens per centimeter
mg/L - Milligrams per liter
mg - N/L - Milligrams nitrogen per liter
mV - Millivolts
NA - Not analyzed
NTU - Nephelometric turbidity unit
pCi/L - picocuries per liter
RL = reporting limit
S.U. - Standard Unit
ug/mL - micrograms per milliliter
2.Analytical methods and reporting limits as presented were applicable at time of CSA field implementation in 2015.Analytical methods and reporting limits are updated periodically and
applied as appropriate.
INORGANICS
FIELD PARAMETERS
1. Select constituents will be analyzed for total and dissolved concentrations.
ANIONS/CATIONS
RADIONUCLIDES
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FIGURE 1PROPOSED MONITORING W ELL LOCATIONSCOAL P ILE AS SESSMENTRIVERBEND ST EAM STATIONDUKE ENE RGY CAROLINAS, LLCMOUNT HOLLY, NORTH CAROLINADRAWN BY: A. FEIGLPROJECT MANAGER: J. MAHANCHECKED BY: B. WYLIE
DATE: 05/30/2018
148 RIVER STREET, SUITE 220GREENVILLE, S OUTH CAROLINA 29601PHONE [phone]www.synterracorp.com
P:\Duke Energy Progress.1026\00 GIS BASE DATA\Riv erbend\MapDocs\Vetting\CoalPileAssess\Riverbend_CoalPileAssess_20180530.mxd
300 0 300 600150
GRAPHIC SC ALE IN FEET
LE GEND
!(PROPOS ED COAL PILE ASSESSMENTMONITORING WE LL LOCATION
")SOIL B ORIN G LOCATIONS
&<EXISTING M ONITORIN G WELL LOCATION
&<OB SE RVATION WELL LOCATION
WE TLAND S [AMEC]
CULTURAL AREA
RAILROAD
TRA NS MISS ION LINE
APP ROXIMATE WASTE BOUNDARY
DUKE P OWER PLA NT BOUNDARY
NOTES:
PROPOSED WELL L OCATI ONS SHOW N ARE APPROXIMATED.EXACT WELL LOCATIONS WIL L BE DETERMINED BASED ONACCESS AND FIELD CONDITIONS AT THE TIME OF W ELLINSTALLATION.
ALL BOUNDARIES ARE APPROXIMATE.
SITE AERIAL ORTHOPHOTOGRAPHY OBTAINED FROMMECKLENBURG COUNTY GIS, DATED 2 017. ADDITIONAL AERIALORTHOPHOTOGRAPHY OBTAINED FROM W SP, 10/30/2015.
DRAWING HAS BEEN SET WIT H A PROJECTION OF NORTHCAROLINA STATE PLANE COORDI NATE SYSTEM FIPS 3200
CATAWBA RIVERCATAWBA RIVER
FORM ERCOAL P ILE
ASH BA SINSECONDARY CELL
ASH BA SINPRIMARY CELL
ASH S TORAGE
CINDERSTORAGE
TECHNICAL MEMORANDUM
P:\Duke Energy Progress.1026\109. Weatherspoon Ash Basin GW Assessment Plan\44.EHS Coal Pile Asmt\Tech
Memo\Version 5\Weatherspoon Coal Pile Asmt Tech Memo.docx
DATE: Revised June 5, 2018 File: 1026.109.44
Submitted January 12, 2018
To: Bryson Sheetz (Duke Energy)
Cc: Kathy Webb (SynTerra)
From: Ted Volskay
Subject: Coal Pile Area Assessment––W.H. Weatherspoon Power Plant
The initial technical memorandum describing groundwater and soil assessment
activities for the W.H. Weatherspoon Power Plant (Weatherspoon, Plant, or Site) was
submitted to the North Carolina Department of Environmental Quality (NC DEQ) in
January 2018. In correspondence dated May 4, 2018, NC DEQ approved the planned
assessment activities and provided comments to be incorporated. This revised technical
memorandum incorporates the NC DEQ comments (see Table 1 for details of the
comments and responses).
Duke Energy Progress, LLC (Duke Energy) owns and operated the W.H. Weatherspoon
Power Plant (Plant or Site) in Lumberton, NC. The Site encompasses approximately 835
acres. Coal-fired power generation operations began in 1949 and ended in October 2011
when the coal-fired units were retired. Coal used for electricity generation was
transported to the Site by railroad and stored on approximately 6.5 acres southeast of
the power generation plant. Groundwater and soil assessment activities for the coal
storage area (coal pile) are described herein.
Regulatory Background
In 2014, The North Carolina General Assembly passed the Coal Ash Management Act
(CAMA). CAMA required owners of a coal combustion residuals (CCR) surface
impoundment to conduct detailed assessment of site groundwater within and around
the CCR surface impoundment.
Groundwater monitoring well AW-2S was installed near the southeastern edge of the
coal pile area during CAMA-associated fieldwork. Inorganic analysis of groundwater
samples collected from well AW-2S detected constituents (aluminum, beryllium,
cadmium, cobalt, copper, nickel, selenium, and zinc) at concentrations uncharacteristic
of Plant background groundwater or groundwater underlying the coal ash basin.
Boron, an indicator constituent of CCR impacts to groundwater, has been detected in
Coal Pile Area Assessment Tech Memo Submitted January 12, 2018, Revised June 5, 2018
W.H. Weatherspoon Power Plant Page 2 of 4
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AW-2S groundwater samples at relatively low concentrations (<165 ug/L). For these
reasons, Duke Energy understands the coal pile area soils and underlying groundwater
to be a potential “secondary source” of inorganic constituents that will be assessed
apart from CAMA.
Station Description
Coal was transported on-site by rail and offloaded onto the coal pile area where it was
stored until burned by coal-powered energy generating units. The coal-fired power
plants have since been demolished and coal is no longer stored onsite. The coal pile
area is approximately 6.5 acres and is located adjacent to and southeast of the former
coal powered power plants (Figure 1). A 225 acre cooling pond is located adjacent to
and southwest of the former coal powered power plants and the coal pile area.
The topography at the coal pile area generally slopes toward the south and southeast.
Surface water that falls on the northeastern half of the coal pile area drains to a low
lying area along the southeast and eastern perimeter of the coal pile area. Surface water
that collects in this area flows into a drainage pipe beyond the western perimeter of the
coal stockpile area. The drainage pipe transports surface water underneath the former
rail spur and the discharge flows into a wetland located between the coal pile area, ash
basin, and cooling pond. Surface water on the southwestern half of the coal pile area
drains toward the south and southwest and into the cooling pond.
Coal Pile Area Assessment Objectives
Objectives of the coal pile area assessment include the following:
Characterize inorganic constituents associated with coal pile area soils
Compare inorganic constituent concentrations in coal pile area soils and site
background soils
Characterize inorganic constituent concentrations in groundwater underlying the
coal pile area and just beyond the coal pile area perimeter
Compare inorganic constituent concentrations in coal pile area groundwater and
site background groundwater

Soil Assessment
Coal pile area soils will be sampled and analyzed for inorganic parameters to determine
if they are a secondary source of coal pile constituents that can leach into underlying
groundwater. Soil samples will be collected from 17 soil boring locations (CPA-SB1
through CPA-SB17) presented in Figure 1 using a GeoProbe© rig. Soil samples will be
collected from the near ground surface (2 to 3 foot) and at approximately 2-foot
intervals to the top of the groundwater table. Soil samples will be analyzed for
Coal Pile Area Assessment Tech Memo Submitted January 12, 2018, Revised June 5, 2018
W.H. Weatherspoon Power Plant Page 3 of 4
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inorganic parameters consistent with assessment of areas used for coal and CCR
management (Table 2).
Continuous soil cores will be collected from the ground surface to the first confining
unit at each proposed well pair and at CPA-2I using a GeoProbe© rig. The continuous
soil cores will serve four purposes:
Continuous soil cores will be used to document the underlying stratigraphy
Continuous soil cores will be used to identify the zones where shallow (Surficial
sands) and intermediate (Yorktown Formation) wells will be screened
Soil samples will be collected from a depth corresponding to the middle of the
shallow and intermediate well screens
Documentation of the underlying stratigraphy (#1 above) will provide the
flexibility of using different types of drill rigs (e.g., rotosonic, hollow-stem auger)
to install the shallow and deep coal pile assessment wells
Groundwater Assessment
Fifteen coal pile assessment (CPA) groundwater monitoring wells will be installed to
characterize coal pile area groundwater. Seven shallow (“S”) and seven intermediate
(“I”) groundwater monitoring wells (CPA-1S/I, CPA-3S/I, CPA-4S/I, CPA-5S/I, CPA-
6S/I, CPA-7S/I, and CPA-8S/I) will be installed as well pairs and CPA-2I will be installed
as a single intermediate well.
Proposed CPA well installation locations are shown on Figure 1 and proposed well
details are provided in Table 3. Groundwater samples will be analyzed for the field
parameters (e.g., pH, conductivity, and turbidity) and inorganic constituents consistent
with assessment of areas used for coal and CCR management Table 4.
Existing fuel oil remediation wells MW-2 and MW-4 will be included in coal pile
groundwater assessment. Both wells are located within the coal pile area footprint.
Well MW-2 is located southeast of the above ground storage tank and well MW-4 is
located south of the above ground storage tank (Figure 1). Both wells have 10 ft. long
well screens and are screened across the water table. The bottom of the MW-2 well
screen is 13.0 ft. below ground surface and The bottom of the MW-2 well screen is 12.7
ft. below ground surface.
Coal Pile Assessment Report
A coal pile assessment report will be prepared once all soil and groundwater sample
analytical data is received. The report will include the following components:
Coal Pile Area Assessment Tech Memo Submitted January 12, 2018, Revised June 5, 2018
W.H. Weatherspoon Power Plant Page 4 of 4
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1) Site History and Source Characterization
2) Site Geology and Hydrogeology
3) Sampling Results (two rounds of groundwater sampling)
4) Site Conceptual Model
5) Conclusions and Recommendations

Coal Pile Area Assessment Tech Memo Submitted January 12, 2018, Revised June 5, 2018
W.H. Weatherspoon Power Plant Page 5 of 4
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Attachments: Figure 1: Proposed Monitoring Well & Soil Boring Location Map
Table 1: Response To NC DEQ Comments - Coal Pile Assessment Work
Plan
Table 2: Soil Analytical Methods
Table 3: Proposed Coal Pile Assessment Soil Samples and Monitoring
Wells
Table 4: Groundwater Analytical Methods

Coal Pile Area Assessment Tech Memo Submitted January 12, Revised June 5, 2018
W.H. Weatherspoon Power Plant

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ATTACHMENTS

12/18/2017 3:35 PMP:\Duke Energy Progress.1026\09.WEATHERSPOON PLANT\09.COAL PILE ASSESSMENT\DWG\DE WEATHERSPOON CPA BASE MAP 2017-12-18.dwg148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE [phone]www.synterracorp.comPROJECT MANAGER:LAYOUT:DRAWN BY:TED VOLSKAYDATE:JOHN CHASTAINFIG 1 (PROP MW & SB LOC MAP)12/18/2017FORMER SMOKE STACKFIGURE 1PROPOSED MONITORING WELL & SOILBORING LOCATION MAPW.H. WEATHERSPOON POWER PLANT491 POWER PLANT RDLUMBERTON, NORTH CAROLINACSA MONITORING WELL (SURVEYED)MONITORING WELL (APPROXIMATE)LEGENDMW-3AW-2SAW-2DAW-2I50050100GRAPHIC SCALEIN FEETMW-53IMW-53DMW-5MW-4MW-3MW-1CW-01CW-01COMPLIANCE MONITORING WELL (SURVEYED)SOURCES:OCTOBER 26, 2016 AERIAL PHOTOGRAPH OBTAINED FROM GOOGLE EARTH PROEXTENT OF COAL STOCKPILE (COMPOSITE)COAL STOCKPILE ASSESSMENT AREAMW-2AW-2DRW-05RW-06RW-03RW-02RW-04RW-01RW-00RW-06FUEL OIL RECOVERY WELL (APPROXIMATE)NO. 2 FUEL OIL AST500,000 GALRETIRED COAL PLANTC
T

P
LAN
T
CT PLANTOIL/WATER SEPARATORCPA-8SCPA-8ICPA-7SCPA-7ICPA-4SCPA-4ICPA-5SCPA-5ICPA-6SCPA-6ICPA-1SCPA-1ICPA-2ICPA-3SCPA-3ICPA-SB5CPA-SB4CPA-SB3CPA-SB2CPA-SB8CPA-SB7CPA-SB1CPA-SB6CPA-SB17CPA-SB16CPA-SB15CPA-SB14CPA-SB11FUEL OIL UNLOADING STATIONFUEL OIL PIPE LINECPA-SB10CPA-SB13CPA-SB12CPA-SB9CPA-SB8CPA-SB12CPA-2IPROPOSED SOIL BORING TO THE TOP OF THE CONFINING LAYERPROPOSED SOIL BORING TO THE TOP OF THE WATER TABLEPROPOSED COAL PILE ASSESSMENT MONITORING WELLFENCEFORMER RAILROAD LINE130128 13
0
128128
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Page 1 of 3

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Responses to NCDEQ Comments.docx
TABLE 1
RESPONSE TO NC DEQ COMMENTS - COAL PILE ASSESSMENT WORK PLAN
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, LLC, LUMBERTON, SC
The W.H. Weatherspoon Coal Pile Assessment Work Plan Technical Memorandum was
submitted to the North Carolina Department of Environmental Quality (NC DEQ) Division of
Water Resources in January 2018. NC DEQ’s approval of the work plan, with comments on the
submittal, was forwarded to Duke Energy on May 4, 2018. Table 1 (below) includes the NC
DEQ comments with a brief summary response and/or the section(s) of the current submittal
containing a detailed response.
NC DEQ Comment 1
The coal pile assessment report is expected to contain necessary evaluations and
interpretations associated with collected data and not just present the results of the
assessment. This may mean incorporation of groundwater assessment data, coal combustion
residuals (CCR) program data, or any other necessary information needed to draw
appropriate, technically supportable conclusions.
Response Summary
Data will be collected and used in the coal pile assessment report to achieve the
objectives of characterizing inorganic constituents in coal pile area soils and
groundwater, including comparison with site background concentrations. As suggested,
this may include CAMA and CCR program data and other available and relevant data
associated with improvement projects in the vicinity of the coal pile.
NC DEQ Comment 2
The following technical direction shall be incorporated into the coal pile assessment:
With the exception of CPA-1S/lD, move the remaining proposed coal pile assessment
wells to the known or assumed perimeter of the former coal pile footprint.
Response Summary
The specific locations of proposed coal pile assessment groundwater monitoring wells
contained in the W.H. Weatherspoon Coal Pile Assessment Work Plan Technical
Memorandum was addressed during the May 18 conference call between Duke Energy and
NCDEQ. NCDEQ said that proposed coal pile assessment groundwater monitoring well
locations were acceptable as proposed in the W.H. Weatherspoon Coal Pile Assessment
Work Plan Technical Memorandum.
NC DEQ Comment 3
The following technical direction shall be incorporated into the coal pile assessment:
• Samples for radionuclide analysis (Radium 226 and 228 and Total Uranium) shall be
collected from soil and groundwater in the proposed soil borings and wells. For soil,
one sample per boring or well pair is sufficient. For groundwater, one groundwater
sample shall be collected in each well.
Table 1 - Response to NC DEQ Comments – Coal Pile Assessment Work Plan June 5, 2018
Duke Energy Progress, LLC, W. H. Weatherspoon Power Plant SynTerra

Page 2 of 3

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Responses to NCDEQ Comments.docx
Response Summary
• One groundwater sample per groundwater monitoring well will be analyzed for
Radium 226, Radium 228, and Total Uranium.
• NCDEQ provided concurrence on May 31, 2018 that soil samples for radionuclide data
do not need to be taken because there is no background data available for comparison.
An email from NCDEQ (S. Lanter) to Duke (B. Grohol) was received on May 31, 2018
acknowledging that "Removal of soil analysis for radionuclides as part of the plans
supersedes previous direction given by Division for the Riverbend and Weatherspoon
facility Coal Pile Assessment Plan comment letters both dated May 4, 2018
• The analytical methods for these analytes are included in Table 4 (formerly Table 3).
NC DEQ Comment 4
The following revisions to the coal pile assessment plan are recommended:
While sonic drilling is proposed as a potential method of installation for the coal pile
assessment wells, using sonic drilling may result in complications, therefore, it is
recommended traditional drilling methods (i.e., auger, air, etc.) be employed. If sonic
drilling is chosen, Duke Energy must ensure that the borehole is properly flushed to
remove drilling fluid/cuttings prior to installation of the monitoring well to reduce the
likelihood of sediment accumulation in the monitoring well which will cause water
quality issues and potentially make development/sampling difficult. These potential
complications may result in installation of replacement wells.
Response Summary
SynTerra considers rotosonic or hollow stem auger drilling technologies to be acceptable
drilling methods for the installation of W.H. Weatherspoon coal pile assessment
groundwater monitoring wells. However, SynTerra will recommend that the hollow stem
auger drilling technique be used to install groundwater monitoring wells proposed in the
Coal Pile Assessment Work Plan Technical Memorandum.
NC DEQ Comment 5
The following revisions to the coal pile assessment plan are recommended:
Proposed well construction involves submerging well screens below the water table. It is
recommended that for shallow wells the screen should not be submerged (intentionally),
but should bracket the water table and if necessary extend the screen interval to 15-ft to
allow the shallow well to accommodate water table fluctuations.
Table 1 - Response to NC DEQ Comments – Coal Pile Assessment Work Plan June 5, 2018
Duke Energy Progress, LLC, W. H. Weatherspoon Power Plant SynTerra

Page 3 of 3

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Responses to NCDEQ Comments.docx
Response Summary
To date, all CAMA and CCR groundwater monitoring wells installed at W.H. Weatherspoon
have been designed so that the well screen is approximately 5 or more feet below the water
table. Duke Energy continues to recommend well installation with top of screen
approximately 5 feet below the water table. That approach is consistent with the approach
for shallow well installation proposed in the Groundwater Assessment Work Plans for DEP
sites submitted to DEQ in December 2014 and implemented in subsequent CAMA-related
well installations. This approach for well screen intervals was outlined in a May 18, 2018,
email from Duke Energy (J. Toepfer) to NCDEQ (S. Lanter). NCDEQ responded via email
(S. Lanter to J. Toepfer) on May 23, 2018, stating “During the May 18, 2018 teleconference
concerning Coal Pile Assessment Plans, Duke Energy requested concurrence concerning the proposed
technical approach for installing well screens approximately 5 feet below the water table. Based on the
supporting rationale presented during the meeting, the Division agrees with the proposed plans for
well construction to support the assessment. However, the Division may expect news wells for other
scopes of work to have screened intervals installed to bracket the water table.”

Duke Energy recommends sampling existing fuel oil remediation wells MW-2 and MW-4.
Both wells are located within the coal pile area footprint. Well MW-2 is located southeast of
the above ground storage tank and well MW-4 is located south of the above ground storage
tank (Figure 1). Both wells have 10 ft. long well screens and are screened across the water
table. The bottom of the MW-2 well screen is 13.0 ft. below ground surface and The bottom
of the MW-2 well screen is 12.7 ft. below ground surface.
NC DEQ Comment 6
The assessment of all other potential sources of groundwater contamination that are located
within the footprint of or that may contribute to the groundwater plumes associated with
impoundment should also be included as part of the updated Comprehensive Site
Assessment.
Response Summary
Other potential sources of groundwater contamination that are located within the footprint
of or that may contribute to the groundwater plumes associated with impoundment will be
included as part of the updated Comprehensive Site Assessment.

TABLE 2
SOIL ANALYTICAL METHODS
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, LLC, LUMBERTON, NC
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INORGANIC COMPOUNDS ANALYTICAL METHODS
Aluminum EPA 6010D
Antimony EPA 6020B
Arsenic EPA 6020A
Barium EPA 6010C
Beryllium EPA 6020B
Boron EPA 6010C
Cadmium EPA 6020A
Calcium EPA 6010C
Chloride EPA 9056A
Chromium EPA 6010C
Cobalt EPA 6020A
Copper EPA 6010C
Iron EPA 6010C
Lead EPA 6020A
Magnesium EPA 6010C
Manganese EPA 6010C
Mercury EPA 7471B
Molybdenum EPA 6010C
Nickel EPA 6010C
Nitrate as Nitrogen EPA 9056A
pH EPA 9045D
Potassium EPA 6010C
Selenium EPA 6020A
Sodium EPA 6010C
Strontium EPA 6010C
Sulfate EPA 9056A
Thallium EPA 6020A
Total Organic Carbon EPA 9060
Vanadium EPA 6020A
Zinc EPA 6010C
Prepared by: RBI Checked by: SRW/TCP/VTV
Notes:
EPA - United States Environmental Protection Agency
TABLE 3
PROPOSED COAL PILE ASSESSMENT SOIL SAMPLES AND MONITORING WELLS
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, LLC, LUMBERTON, NC
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Monitoring
Well ID
Estimated
Well Depth
(feet bgs)
Soil Sample ID
(Estimated Depth
Interval in feet bgs)
Comments
----CPA-SB1 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB1 (5-6)Unsaturated soil sample
----CPA-SB1 (8-9)Unsaturated soil sample
----CPA-SB1 (11-12)Unsaturated soil sample
----CPA-SB1 (14-15)Unsaturated soil sample
----CPA-SB1 (17-18)Unsaturated soil sample
CPA-1S 35 CPA-SB1 (29-31)Soil sample from shallow well screened interval
CPA-1I 65 CPA-SB1 (59-61)Soil sample from deep well screened interval
----CPA-SB2 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB2 (5-6)Unsaturated soil sample
----CPA-SB2 (8-9)Unsaturated soil sample
----CPA-SB2 (11-12)Unsaturated soil sample
----CPA-SB2 (14-15)Unsaturated soil sample
----CPA-SB2 (17-18)Unsaturated soil sample
CPA-2I 65 CPA-SB2 (59-61)Soil sample from deep well screened interval
----CPA-SB3 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB3 (5-6)Unsaturated soil sample
----CPA-SB3 (8-9)Unsaturated soil sample
----CPA-SB3 (11-12)Unsaturated soil sample
----CPA-SB3 (14-15)Unsaturated soil sample
----CPA-SB3 (17-18)Unsaturated soil sample
CPA-3S 35 CPA-SB3 (29-31)Soil sample from shallow well screened interval
CPA-3I 65 CPA-SB3 (59-61)Soil sample from deep well screened interval
----CPA-SB4 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB4 (5-6)Unsaturated soil sample
----CPA-SB4 (8-9)Unsaturated soil sample
----CPA-SB4 (11-12)Unsaturated soil sample
----CPA-SB4 (14-15)Unsaturated soil sample
----CPA-SB4 (17-18)Unsaturated soil sample
CPA-4S 35 CPA-SB4 (29-31)Soil sample from shallow well screened interval
CPA-4I 65 CPA-SB4 (59-61)Soil sample from deep well screened interval
----CPA-SB5 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB5 (5-6)Unsaturated soil sample
----CPA-SB5 (8-9)Unsaturated soil sample
----CPA-SB5 (11-12)Unsaturated soil sample
----CPA-SB5 (14-15)Unsaturated soil sample
----CPA-SB5 (17-18)Unsaturated soil sample
CPA-5S 35 CPA-SB5 (29-31)Soil sample from shallow well screened interval
CPA-5I 65 CPA-SB5 (59-61)Soil sample from deep well screened interval
----CPA-SB6 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB6 (5-6)Unsaturated soil sample
----CPA-SB6 (8-9)Unsaturated soil sample
----CPA-SB6 (11-12)Unsaturated soil sample
----CPA-SB6 (14-15)Unsaturated soil sample
----CPA-SB6 (17-18)Unsaturated soil sample
CPA-6S 35 CPA-SB6 (29-31)Soil sample from shallow well screened interval
CPA-6I 65 CPA-SB6 (59-61)Soil sample from deep well screened interval
----CPA-SB7 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB7 (5-6)Unsaturated soil sample
----CPA-SB7 (8-9)Unsaturated soil sample
----CPA-SB7 (11-12)Unsaturated soil sample
----CPA-SB7 (14-15)Unsaturated soil sample
----CPA-SB7 (17-18)Unsaturated soil sample
CPA-7S 35 CPA-SB6 (29-31)Soil sample from shallow well screened interval
CPA-7I 65 CPA-SB6 (59-61)Soil sample from deep well screened interval
----CPA-SB8 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB8 (5-6)Unsaturated soil sample
----CPA-SB8 (8-9)Unsaturated soil sample
----CPA-SB8 (11-12)Unsaturated soil sample
----CPA-SB8 (14-15)Unsaturated soil sample
----CPA-SB8 (17-18)Unsaturated soil sample
CPA-8S 35 CPA-SB8 (29-31)Soil sample from shallow well screened interval
CPA-8I 65 CPA-SB8 (59-61)Soil sample from deep well screened interval
TABLE 3
PROPOSED COAL PILE ASSESSMENT SOIL SAMPLES AND MONITORING WELLS
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, LLC, LUMBERTON, NC
P:\Duke Energy Progress.1026\109. Weatherspoon Ash Basin GW Assessment Plan\44.EHS Coal Pile Asmt\Tech Memo\Version 5\Table 3 Weatherspoon Coal Pile Asmt Tech Memo Page 2 of 2
Monitoring
Well ID
Estimated
Well Depth
(feet bgs)
Soil Sample ID
(Estimated Depth
Interval in feet bgs)
Comments
----CPA-SB9 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB9 (5-6)Unsaturated soil sample
----CPA-SB9 (8-9)Unsaturated soil sample
----CPA-SB9 (11-12)Unsaturated soil sample
----CPA-SB9 (14-15)Unsaturated soil sample
----CPA-SB9 (17-18)Unsaturated soil sample
----CPA-SB10 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB10 (5-6)Unsaturated soil sample
----CPA-SB10 (8-9)Unsaturated soil sample
----CPA-SB10 (11-12)Unsaturated soil sample
----CPA-SB10 (14-15)Unsaturated soil sample
----CPA-SB10 (17-18)Unsaturated soil sample
----CPA-SB11 (2-31 Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB11 (5-6)Unsaturated soil sample
----CPA-SB11 (8-9)Unsaturated soil sample
----CPA-SB11 (11-12)Unsaturated soil sample
----CPA-SB11 (14-15)Unsaturated soil sample
----CPA-SB11 (17-18)Unsaturated soil sample
----CPA-SB12 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB12 (5-6)Unsaturated soil sample
----CPA-SB12 (8-9)Unsaturated soil sample
----CPA-SB12 (11-12)Unsaturated soil sample
----CPA-SB12 (14-15)Unsaturated soil sample
----CPA-SB12 (17-18)Unsaturated soil sample
----CPA-SB13 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB13 (5-6)Unsaturated soil sample
----CPA-SB13 (8-9)Unsaturated soil sample
----CPA-SB13 (11-12)Unsaturated soil sample
----CPA-SB16 (14-15)Unsaturated soil sample
----CPA-SB13 (17-18)Unsaturated soil sample
----CPA-SB14 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB14 (5-6)Unsaturated soil sample
----CPA-SB14 (8-9)Unsaturated soil sample
----CPA-SB14 (11-12)Unsaturated soil sample
----CPA-SB14 (14-15)Unsaturated soil sample
----CPA-SB14 (17-18)Unsaturated soil sample
----CPA-SB15 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB15 (5-6)Unsaturated soil sample
----CPA-SB15 (8-9)Unsaturated soil sample
----CPA-SB15 (11-12)Unsaturated soil sample
----CPA-SB15 (14-15)Unsaturated soil sample
----CPA-SB15 (17-18)Unsaturated soil sample
----CPA-SB16 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB16 (5-6)Unsaturated soil sample
----CPA-SB16 (8-9)Unsaturated soil sample
----CPA-SB16 (11-12)Unsaturated soil sample
----CPA-SB16 (14-15)Unsaturated soil sample
----CPA-SB16 (17-18)Unsaturated soil sample
----CPA-SB17 (2-3)Unsaturated soil sample (water table <20 feet bgs)
----CPA-SB17 (5-6)Unsaturated soil sample
----CPA-SB17 (8-9)Unsaturated soil sample
----CPA-SB17 (11-12)Unsaturated soil sample
----CPA-SB17 (14-15)Unsaturated soil sample
----CPA-SB17 (17-18)Unsaturated soil sample
Prepared by: VTV Checked by: KLS
Notes:
bgs = below ground surface
~ = Approximately
SynTerra recommends rotosonic or hollow-stem auger drilling methods for boring and well installation.
Continuous cores from GeoProbe drilling provide sufficient material for soil sampling and lithologic description.
Estimated well and soil sample depths based on data from the AW-2S, CW-1, CCR-105 and CCR-106 well clusters.
Number of soil samples shown is approximate. A shallower water table will result in fewer samples, and a deeper water table will result in additional samples.
SynTerra recommends each well screen be submerged beneath the water table and have a length of at least 10 feet.
TABLE 4
GROUNDWATER ANALYTICAL METHODS
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, LLC, LUMBERTON, NC
P:\Duke Energy Progress.1026\109. Weatherspoon Ash Basin GW Assessment Plan\44.EHS Coal Pile Asmt\Tech Memo\Version 5\Table 4 Weatherspoon Coal Pile Asmt Tech Memo Page 1 of 1
PARAMETER RL UNITS METHOD
pH NA SU Field Water Quality Meter
Specific Conductance NA µS/cm Field Water Quality Meter
Temperature NA ºC Field Water Quality Meter
Dissolved Oxygen NA mg/L Field Water Quality Meter
Oxidation Reduction Potential NA mV Field Water Quality Meter
Turbidity NA NTU Field Water Quality Meter
Ferrous Iron NA mg/L Field Test Kit
Aluminum 0.005 mg/L EPA 200.7 or 6010D
Antimony 0.001 mg/L EPA 200.8 or 6020B
Arsenic 0.001 mg/L EPA 200.8 or 6020A
Barium 0.005 mg/L EPA 200.7 or 6010C
Beryllium 0.001 mg/L EPA 200.8 or 6020A
Boron 0.05 mg/L EPA 200.7 or 6010C
Cadmium 0.001 mg/L EPA 200.8 or 6020A
Chromium 0.001 mg/L EPA 200.8 or 6010C
Cobalt 0.001 mg/L EPA 200.8 or 6020A
Copper 0.001 mg/L EPA 200.8 or 6020B
Hexavalent Chromium 0.000025 mg/L EPA 218.7
Iron 0.01 mg/L EPA 200.7 or 6010C
Lead 0.001 mg/L EPA 200.8 or 6020A
Lithium 1 mg/L EPA 200.7 or 6010D
Manganese 0.005 mg/L EPA 200.7 or 6010C
Mercury (low level)0.005 ng/L 1631 ONLY
Molybdenum 0.001 mg/L EPA 200.8 or 6020B
Nickel 0.001 mg/L EPA 200.8 or 6020B
Phosphorus 0.005 mg/L EPA 365.1
Selenium 0.001 mg/L EPA 200.8 or 6020A
Strontium 0.005 mg/L EPA 200.7 or 6010C
Thallium (low level)0.0002 mg/L EPA 200.8 or 6020A
Vanadium (low level)0.0003 mg/L EPA 200.8 or 6020A
Zinc 0.005 mg/L EPA 200.7 or 6010C
Radium 226 1 pCi/L EPA 903.1 Modified
Radium 228 1 pCi/L EPA 904.0/SW846 9320 Modified
Uranium (233, 234, 236, 238)Varies by isotope ug/ml SW846 3010A/6020A
Alkalinity (as CaCO3)5 mg/L SM 2320B
Bicarbonate 5 mg/L SM 2320
Calcium 0.01 mg/L EPA 200.7
Carbonate 5 mg/L SM 2320
Chloride 0.1 mg/L EPA 300.0 or 9056A
Magnesium 0.005 mg/L EPA 200.7
Methane 0.01 mg/L RSK 175
Nitrate as Nitrogen 0.01 mg-N/L EPA 353.2
Potassium 0.1 mg/L EPA 200.7
Sodium 0.05 mg/L EPA 200.7
Sulfate 0.1 mg/L EPA 300.0 or 9056A
Sulfide 0.1 mg/L SM4500S2-D
Total Dissolved Solids 25 mg/L SM 2540C
Total Organic Carbon 0.1 mg/L SM 5310C/EPA9060A
Total Suspended Solids 2.5 mg/L SM 2450D
Prepared by: RBI Checked by: SRW/TCP/VTV
Notes:
ºC - Degrees Celsius
µS/cm = micro-Siemens per centimeter
mg/L - Milligrams per liter
mg - N/L - Milligrams nitrogen per liter
mV - Millivolts
NA - Not analyzed
NTU - Nephelometric turbidity unit
pCi/L - picocuries per liter
RL = reporting limit
SU - standard unit
ug/mL - micrograms per milliliter
2.Analytical methods and reporting limits as presented were applicable at time of CSA field implementation in 2015.Analytical methods and reporting limits are updated periodically and
applied as appropriate.
INORGANICS
FIELD PARAMETERS
1. Select constituents may be analyzed for total and dissolved concentrations.
ANIONS/CATIONS
RADIONUCLIDES
1

Meeting Minutes

Project: Duke Energy Coal Pile Assessments – Allen, Riverbend, and Weatherspoon
Subject: Meeting to Discuss NCDEQ Comments to Coal Pile Assessment Work Plans
Date: Friday, May 18, 2018 13:00 - 13:56
Location: Conference Call (organized by Duke Energy)

Meeting Attendees

Duke Energy NCDEQ SynTerra
John Toepfer Kent White Judd Mahan
Ryan Czop Shuying Wang Chris Suttell
Bristol Grohol Jay Zimmerman
Courtney Murphy Steve Lanter
Julie Robertson Brandy Costner
Bryson Sheetz Joanna Harbison

Meeting Purpose
The purpose of the meeting is to discuss comments recently received from NCDEQ on the Coal Pile
Assessment Work Plans for the Allen, Riverbend, and Weatherspoon sites, submitted in January 2018.
Meeting Summary
Use of Sonic Drilling at 3 sites (Allen, Riverbend, and Weatherspoon)
NCDEQ expressed concerns with sonic drilling methods for deep and bedrock wells due to
potential elevated turbidity given water amounts typically required for the sonic method.
NCDEQ’s position is if well integrity issues are encountered, the expectation is the well will be
replaced regardless of drill method chosen.
Duke mentioned that they have installed over 1,500 wells at various sites with relatively few
pH/turbidity issues. SynTerra mentioned that in prior instances of pH issues at Allen,
Duke/SynTerra feel it is likely attributed to a previous consultant using grout as a backfill (rather
than bentonite or sand ) when the borehole overshot anticipated well depth.
NCDEQ mentioned they prefer to see bentonite-grout used, and recommended consulting
closely with drillers to use appropriately-sized filter packs and screens, and additionally, using
centralizers to ensure uniform annulus space around well for filter pack. NCDEQ mentioned
2

that when determining most suitable drilling method, be aware that different methods might
introduce variables in well construction that are difficult to manage.
Submerged Well Screens for Shallow Groundwater Wells (Allen, Riverbend, and
Weatherspoon)
The pros and cons of submerged shallow screen for this scope were listed by Duke/SynTerra
on the respective meeting agenda. NCDEQ will review and provide a response early next week
(week of May 21, 2018). NCDEQ mentioned that the industry standard is to bracket the water
table for shallow wells, but for the purpose of metals analysis, NCDEQ will internally discuss
and consider if screens can be submerged for this scope. Duke mentioned that justification for
submerging the screens for similar scopes/purposes had previously been approved for DEP
sites.
Relocation of W ells to Coal Pile Perimeter vs More Downgradient Location (Riverbend and
Weatherspoon)
Riverbend – NCDEQ suggested relocating wells closer to the former coal pile footprint so that
soil data can be collected within the former coal pile area. Duke/Synterra explained that if wells
were added closer to the former coal pile footprint, they would be too close to the wells to the
west and north of the coal pile, which are located as close to the water’s edge as possible
(limited by steep terrain and wetlands). Duke/SynTerra and NCDEQ agreed to keep the
originally proposed well locations and perform additional soil borings at the perimeter of the
former coal pile. NCDEQ requested collection of radionuclide samples from material just above
the water table; i.e. “the smear zone” at each well cluster and soil boring location.
Weatherspoon – Duke/SynTerra and NCDEQ agreed to keep the originally proposed well
locations.
Site Specific Comments
Allen – NCDEQ recommended comparison of data from Coal Pile Assessment with data
observed downgradient of ash basin. Duke mentioned this will be a useful data comparison but
may not be appropriate to include in a Coal Pile Assessment Report if it is a stand-alone report.
NCDEQ expressed that they would prefer not to have separate reports for additional source
areas; however, with several Corrective Action Plan (CAP) dates not currently set, it is difficult to
determine if additional sources areas can be included in the CAP. It will be determined at a
later date in what document/report this information should be included.
Riverbend – NCDEQ is concerned with the ~120-foot depth variation between the shallow and
deep wells and recommended this difference in depth be reduced. Duke/Synterra explained
that the saprolite layer at Riverbend is very thick and the proposed deep well depth intends to
capture the transition zone. The well depths may be adjusted depending on field conditions.
3

Weatherspoon – Duke mentioned that a large portion of the coal pile area is inaccessible due to
the AST fuel remediation. NCDEQ inquired if Duke could collect samples at existing wells
within the AST remediation field. Duke to vet if this will be possible and/or appropriate for the
Coal Pile Assessment scope.
Action Items
• Duke/SynTerra to resubmit revised plans with revised figures.

• NCDEQ to respond to Duke early next week (week of May 21, 2018) in regards to
submerged screens for shallow wells.

• Duke to determine if sampling AST remediation wells is possible and/or appropriate for the
Coal Pile Assessment scope.

• Duke/SynTerra to schedule a walkdown to stake well locations at Allen, and Duke to invite
Brandy and Joanna from NCDEQ MRO to attend.

END NOTES