2019_11_27 Coal Pile Assessment Tech Memo - Cliffside - Addendum

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TECHNICAL MEMORANDUM
Date: November 27, 2019 File: 1026.21.060
To: Ryan Czop (Duke Energy)
Cc: Kathy We7.,OPJ--
From: Scott Spinner
Subject: Soil and Groundwater Assessment Addendum - Coal Pile - Cliffside Steam
Station
Duke Energy Carolinas, LLC (Duke Energy) owns and operates the Rogers Energy
Complex (henceforth referred to as the Cliffside Steam Station (CSS), or the site), which
is located in Mooresboro, Rutherford and Cleveland Counties, North Carolina. CSS
began operation in 1940 as a coal-fired generating station. Units 1 through 4 were
retired in October 2011, and currently only Units 5 and 6 are in operation at CSS. Coal
used for electricity generation is transported to the Site by railroad and stored on
approximately 22 acres northeast of the the Unit 5 power generation plant and north of
the Unit 6 power generation plant. The coal ash residue and other liquid discharges
from coal combustion processes at CSS have historically been managed in CSS ash
basins, which consist of the active ash basin, the former Units 1-4 ash basin, and the
Unit 5 inactive ash basin.
An initial soil and groundwater assessment of the coal pile was conducted from May
2019 through July 2019. Thirteen (13) monitoring wells were installed in general
accordance with the Soil and Groundwater Assessment — Coal Pile — Cliffside Steam Station
Technical Memorandum dated June 29, 2018 (workplan). The workplan was approved by
NCDEQ in a July 31, 2018 letter from Jon Risgaard, Chief, Animal Feeding Operations
and Groundwater Section to Paul Draovitch, Senior Vice President, with Duke Energy.
The monitoring well locations and well identifications for the installed assessment wells
are presented on Figure 1. A well construction table is provided as Table 1.
An initial round of sampling and analysis of groundwater from the coal pile assessment
wells was conducted in July 2019. The analytical results have been previously
submitted to NCDEQ in the August 2019 quarterly comprehensive data submittal.
Based on the analytical results from the coal pile wells, the horizontal and vertical
extent of groundwater impacts around the CSS coal pile have not been delineated.
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Memo - Cliffside - Addendum.docx

Soil and Groundwater Assessment Addendum — Coal Pile November 27, 2019
Cliffside Steam Station
Page 2 of 4
Additional groundwater and soil assessment activities for the coal pile to delineate the
horizontal and vertical extent of groundwater impacts 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 not installed near the coal pile during CAMA-
associated fieldwork. Duke Energy understands the soils beneath the coal pile may be a
potential "secondary source" of inorganic constituents that will be assessed apart from
CAMA.
Station Description
Coal-fired power generation operations began at CSS in 1940. Coal is transported on -
site by rail and offloaded onto the coal pile area where it is stored until burned by the
coal -powered energy generating units. The coal pile area is approximately 22 acres and
is located northeast of the the Unit 5 power generation plant and north of the Unit 6
power gerneration plant. A liner is located beneath approximately four acres of the
eastern end of the coal pile.
Coal Pile Area Additional Assessment Objectives
Objectives of the coal pile area additional assessment activities include the following:
• Characterize inorganic constituents associated with coal pile area soils
• Characterize the horizontal and vertical extent of inorganic constituent
concentrations in groundwater surrounding the coal pile area
• Compare inorganic constituent concentrations in coal pile area groundwater and
site background groundwater
Soil Assessment
Coal pile area soils are proposed to be sampled and analyzed for inorganic parameters
to determine if the soil may be a secondary source of coal pile constituents that could
leach into underlying groundwater. Soil samples are proposed to be collected at
proposed monitoring well locations (CP-7, CP-8, and CP-9) as part of well installation
activities (Figure 1). Due to the coal pile being active, soil samples directly beneath the
footprint of the coal pile will not be accessible. Soil samples will be collected at
approximately 5-foot intervals to the top of the groundwater table. An additional
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Soil and Groundwater Assessment Addendum — Coal Pile November 27, 2019
Cliffside Steam Station Page 3 of 4
shallow soil sample will be collected below the water table within the new well
screened intervals. Samples of bedrock will not be collected for analysis. Soil samples
will be analyzed for inorganic parameters as listed on Table 2. Soil samples will also be
collected approximately 5-feet below ground surface and the interval immediately
above the water table and analyzed for leachable inorganics using Synthetic
Precipitation Leaching Procedures (SPLP) at each well cluster location.
Groundwater Assessment
Thirteen coal pile assessment (CP) groundwater monitoring wells are proposed to be
installed to characterize the horizontal and vertical extent of coal pile area impacts to
groundwater. Three shallow ("S"), three deep ("D"), and seven bedrock ("BR")
groundwater monitoring wells (CP-1BR, CP-3BRL, CP-4BR/BRL, CP-7S/D/BR, CP-
8S/D/BR, and CP-9S/D/BR) are proposed to be installed. Proposed approximate
additional CP well installation locations are shown on Figure 1 and proposed well
details are provided as Table 3. Shallow groundwater monitoring wells will be installed
approximately 5 feet below the water table. 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. Groundwater
samples from monitoring wells CP-3BRL, CP-4BR/BRL, CP-8S/D/BR, and CP-9S/D/BR
will also be analyzed for total uranium, radium-226, and radium-228.
Coal Pile Assessment Report
A coal pile comprehensive site assessment report (CSA) will be prepared and submitted
to NCDEQ by March 31, 2020. Groundwater data available by February 1, 2020 will be
included in the CSA report. If data for the additional monitoring wells in not available
in time for inclusion in the CSA report an addendum to the report may be necessary.
Additional existing site data will be used in characterizing the coal pile soils and
groundwater, including CAMA and CCR program data. 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
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Memo - Cliffside - Addendum.docx

Soil and Groundwater Assessment Addendum - Coal Pile
November 27, 2019
Cliffside Steam Station
ATTACHMENTS:
Table 1: Monitoring Well Construction
Table 2: Soil Analytical Methods
Table 3: Proposed Coal Pile Assessment Soil Samples and Monitoring Wells
Table 4: Groundwater Analytical Methods
Figure 1: Additional Coal Pile Assessment Proposed Monitoring Wells
Page 4 of 4
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Action \ Assessment \ Coal Pile Assessment \ Coal Pile Assessment Workplan - Addendum \ Coal Pile Assessment Tech
Memo - Cliffside - Addendum.docx

Soil and Groundwater Assessment — Coal Pile
November 22, 2019
Cliffside Steam Station
ATTACHMENTS
P:\Duke Energy Carolinas \ 21. CLIFFSIDE \ 06.EHS-CAMA Compliance Support and Corrective
Action\ Assessment\ Coal Pile Assessment\Coal Pile Assessment Workplan - Addendum\Coal Pile Assessment Tech
Memo - Cliffside - Addendum.docx

TABLE 1
MONITORING WELL CONSTRUCTION
COAL PILE ASSESSMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Well ID
Well Installed
Outer Casing Depth
(6-inch)
(ft bgs)
Well Screen
Interval
(ft bgs)
( S U.)
Turbidity
Flow Layer
Surface Completion
CP-1D
6/11/2019
N/A
39.1-49.1
3.84
7.3
Deep
Stick-up
CP-2S
6/4/2019
N/A
37-47
5.09
8.6
Shallow
Flush Mount
CP-2BRU
6/10/2019
48.0
57-67
6.91
9.1
Deep
Flush Mount
CP-2BR
6/11/2019
48.0
167-177
8.38
7.5
Bedrock
Flush Mount
CP-3S
5/31/2019
N/A
37-47
5.31
3.6
Shallow
Flush Mount
CP-3BR
5/31/2019
71.0
107-117
5.74
9.9
Bedrock
Flush Mount
CP-4S
5/29/2019
N/A
31-36
3.63
9.5
Shallow
Stick-up
CP-4BRU
5/29/2019
43.0
49-59
3.45
7.8
Deep
Stick-up
CP-SS
5/22/2019
N/A
39.9-49.9
5.32
7.6
Shallow
Stick-up
CP-5I
5/20/2019
110.0
113-123
5.49 7.8
Shallow
Stick-up
CP-5BR
5/22/2019
127.0
166-176
7.53
9.8
Bedrock
Stick-up
CP-6S
6/12/2019
N/A
42-47
5.67
8.9
Shallow
Flush Mount
CP-6BR
6/13/2019
49.0
117-127
7.64
9.5
Bedrock
Flush Mount
Notes:
ft bgs - feet below ground surface
S.U. - Standard Units
NTU - Nephelometric Turbidity Units
pH and turbidity readings were taken after well development
Prepared by: TJG Checked by: SAS
Page 1 of 1

TABLE 2
SOIL ANALYTICAL METHODS
COAL PILE ASSESSMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
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
Prepared by: RBI Checked by: SRW/TCP
Notes•
1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045; select soil samples will
also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with USEPA Methods 6010/6020.
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.
meq/100g - millequivalents per 100 grams
mg/kg - Milligrams per kilogram
my - Millivolts
S.U. - Standard Unit
Page 1 of 1

TABLE 3
PROPOSED COAL PILE ASSESSMENT SOIL SAMPLES AND MONITORING WELLS
COAL PILE ASSESSMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Monitoring
Well I
Estimated
Well Depth
(feet bgs)
Soil Sample ID
(Estimated Depth
Interval in feet bgs)
Comments
C13-11311
120
CP-1SB (110-120)
HAO/HFO sample
CP-3BRL
200
CP-3SB (190-200)
HAO/HFO sample
C13-41311
120
CP-3SB (110-120)
HAO/HFO sample
CP-4BRL
200
CP-3SB (190-200)
HAO/HFO sample
--
--
CP-7SB (3.5-5)
Near -surface unsaturated soil sample (water table —25 feet bgs)
--
--
CP-7SB (8.5-10)
Unsaturated soil sample
--
--
CP-7SB (13.5-15)
Unsaturated soil sample
--
--
CP-7SB (18.5-20)
Unsaturated soil sample
--
--
CP-7SB (23.5-25)
Unsaturated soil sample
CP-7S
40
CP-7SB (33.5-35)
Soil sample from shallow well screened interval, HAO/HFO sample
CP-7D
60
CP-7SB (53.5-55)
Soil sample from deep well screened interval, HAO/HFO sample
CP-71311
130
CP-7SB (128.5-130)
HAO/HFO sample
--
--
CP-8SB (3.5-5)
Near -surface unsaturated soil sample (water table "25 feet bgs)
--
--
CP-8SB (8.5-10)
Unsaturated soil sample
--
--
CP-8SB (13.5-15)
Unsaturated soil sample
--
--
CP-8SB (18.5-20)
Unsaturated soil sample
--
--
CP-8SB (23.5-25)
Unsaturated soil sample
CP-8S
40
CP-8SB (33.5-35)
Soil sample from shallow well screened interval, HAO/HFO sample
CP-8D
60
CP-8SB (53.5-55)
Soil sample from deep well screened interval, HAO/HFO sample
CP-81311
130
CP-8SB (128.5-130)
HAO/HFO sample
--
--
CP-9SB (3.5-5)
Near -surface unsaturated soil sample (water table —25 feet bgs)
--
--
CP-9SB (8.5-10)
Unsaturated soil sample
--
--
CP-9SB (13.5-15)
Unsaturated soil sample
--
--
CP-9SB (18.5-20)
Unsaturated soil sample
--
--
CP-9SB (23.5-25)
Unsaturated soil sample
CP-9S
40
CP-9SB (33.5-35)
Soil sample from shallow well screened interval, HAO/HFO sample
CP-913
60
CP-9SB (53.5-55)
Soil sample from deep well screened interval, HAO/HFO sample
CP-9BR
130
CP-9SB (128.5-130)
HAO/HFO sample
Prepared by: SAS Checked by: TJG
Notes:
bgs = below ground surface
— = Approximately
SynTerra recommends hollow stem auger and air rotary or sonic methods for boring and well installation.
Continuous cores from air rotary or sonic drilling provide sufficient material for soil sampling and lithologic description.
Estimated well and soil sample depths based on data from the existing 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 the shallow monitoring wells be installed approximately 5 feet below the water table and have a length of at least 10 feet.
Page 1 of 1

TABLE 4
GROUNDWATER ANALYTICAL METHODS
COAL PILE ASSESSMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
PARAMETER RL UNITS IMETHOD
FIELD PARAMETERS
pH
NA
SU
Field Water Quality Meter
Specific Conductance
NA
VS/CM
Field Water Quality Meter
Temperature
NA
0C
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
INA
INTU
Field Water Quality Meter
INORGANICS
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)
10.0003
mg/L
I EPA 200.8 or 6020B
Zinc
10.005
mg/L
I EPA 200.7 or 6010D
RADIONUCLIDES
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
ANIONS/CATIONS/OTHER
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
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
Prepared by: HHS Checked by: RH]
Page 1 of 1

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t NOTES:
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•� - '.r , '< ",• }_! ,,, _ ENGINEERS AT THE TIME OF THE MAP CREATION. THIS MAP IS NOT TO BE USED FOR
JURISDICTIONAL DETERMINATION PURPOSES. THE WETLANDS AND STREAMS
.. = ti - BOUNDARIES WERE OBTAINED FROM AMEC FOSTER WHEELER ENVIRONMENTAL
AND ♦� - INFRASTRUCTURE, INC NATURAL RESOURCE TECHNICAL REPORT (NRTR) FOR
�' ,� f �'F ♦� ♦ _ CLIFFSIDE STEAM STATION DATED JUNE 19, 2015.
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yl� ; '; r ' ♦', - - 2. AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON SEPTEMBER 7,
-``,� 2018. IMAGE COLLECTED ON APRIL 20, 2018.
3. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
y COORDINATE SYSTEM RIPS 3200 (NAD83).
150 D 150 300 FIGURE 1
GRAPHIC SCALE IN FEET
ADDITIONAL COAL PILE ASSESSMENT
synTerra PROPOSED MONITORING WELLS
DRAWN BY: C. DAVIS Date: 10/01/2019
ti CHECKREVISEDBY.C.DAVIS.GRA Date:11/13/2019 CLIFFSIDE STEAM STATION
Y x - ♦ - ~ - '�~ �. "+� �' DUKE CHECKED BY. T. GRANT Date: 11/13/2019
, ' "�♦ r _ t R a-. ENERGY PROJECT MANAGER: S. SPINNER Date:11/13/2019 MOORESBORO, NORTH CAROLINA
�-` CAROLINA S
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