NC0004987_Appendix D_Soil and Rock Characterization_20150908

Sampling Procedures
Sampling Overview
Characterization of subsurface materials was conducted through the completion of soil borings
and borings performed for installation of monitoring wells as described below. Installation details
for soil borings and monitoring wells, as well as sample quantities and depths, are described
below.
For nested monitoring wells, the deep boring was utilized for characterization of subsurface
material and collection of environmental and/or geotechnical samples for lab analyses.
Standard Penetration Testing (SPT) was conducted utilizing split -spoon sampling techniques at
five foot increments with an 18-inch split -spoon sampler. Any environmental and/or
geotechnical samples not able to be collected in the deep well were collected in either the
shallow or bedrock well that was paired with the deep well. Geotechnical samples consisted of
undisturbed (Shelby tube) samples (natural moisture content, grain size with hydrometer,
hydraulic conductivity, and specific gravity), sorption samples (Kd/HFO), mineralogy, and index
property samples (natural moisture content and grain size with hydrometer). Environmental
sampling for soils consisted of Total Inorganic compounds (TI) and Total Organic Carbon (TOC)
and environmental sampling for ash consisted of TI, TOC, and Synthetic Precipitation Leaching
Potential (SPLP). In situations where there was a single well to installed, as many samples as
possible were collected in that boring, but if it was not feasible to collect the necessary samples
a second boring (geotechnical boring) was advanced within five ft of the original boring to obtain
the remaining samples.
Sampling equipment was decontaminated between each sample interval in the same borehole
as well as between each boring. Sampling equipment was first rinsed with tap water, washed
with a water-liquinox mix and then rinsed a final time with deionized water. All downhole
equipment utilized during boring/well installation (i.e.; augers, drill rods, split spoons, etc.) were
decontaminated between each borehole to eliminate potential cross contamination between
boreholes. A decontamination pad was constructed for field cleaning of downhole tooling.
Downhole tooling was decontaminated using a high temperature, high pressure steam cleaner
followed by rinsing with potable water.
Ash and Soil Borings
Characterization of ash and underlying soil will be accomplished through the completion and
sampling of borings advanced at 21 monitoring well locations within the ash basin and on the
ash basin dike (designated as AB-1 through AB-21), 4 monitoring well locations within and
immediately adjacent to the ash landfill areas (designated as AL-1 through AL-4), and 15 soil
boring locations in the ash basin and structural fill area (designated as SB-1 through SB-15). In
addition, 12 soil borings (designated as GWA-1 through GWA-9 and BG-1 through BG-3) will be
completed outside of ash management areas to provide additional soil quality data.

Duke Energy notified the Division of Waste Management (DWM) prior to installing proposed
borings/monitoring wells located adjacent to and within the permitted Dry Ash Landfill
(designated as AL-1 S/D, AL-2S/D, AL-3S/D, and AL-4D) and within the Structural Fill
(designated as SB-2 through SB-9 and AB-20S/D).
Field data collected during boring advancement was used to evaluate:
• the presence or absence of ash
• areal extent and depth/thickness of ash
• groundwater flow and transport characteristics if groundwater is encountered
Borings were advanced using hollow stem auger or roller cone drilling techniques to facilitate
collection of down -hole data. Standard Penetration Testing (SPT) (ASTM D 1586) and split -
spoon sampling was performed at 5-foot increments using an 18-inch split -spoon sampler. Soil
borings located within the waste boundary that were not be used for installation of monitoring
wells (SB-1 through S13-15) extended approximately 20 feet below the ash/native soil interface
or to refusal, whichever is encountered first. Note that continuous coring was performed from
auger refusal to a depth of at least 50 feet into competent bedrock for bedrock monitoring well
borings (designated as BR soil boring/groundwater monitoring well locations).
Borings were logged and ash/soil samples were photographed, described, and visually
classified in the field for origin, consistency/relative density, color, and soil type in accordance
with the Unified Soil Classification System (ASTM D2487/D2488).
BORINGS WITHIN ASH BASIN WASTE BOUNDARY
In areas where ash is known or suspected to be present (i.e., AB- and S-borings), solid phase
samples were collected for laboratory analysis from the following intervals in each boring:
• Shallow Ash — approximately 3 feet to 5 feet bgs
• Deeper Ash — approximately 2 feet above the ash/soil interface
• Upper Soil — approximately 2 feet below the ash/soil interface
• Deeper Soil — approximately 8 feet to 10 feet below the ash/soil interface
If ash was observed to be greater than 30 feet thick, a third ash sample was collected from the
approximate mid -point depth between the shallow and deeper samples. The ash samples were
used to evaluate geochemical variations in ash located in the ash basin and ash storage. The
upper and deeper soil samples were used to delineate the vertical extent of potential soil
impacts beneath the ash basin, ash landfill, and structural fill.
Ash and soil samples were analyzed for total inorganic compounds.
Select ash and soil samples were be analyzed for leachable inorganic compounds using the
Synthetic Precipitation Leaching Procedure (SPLP) to evaluate the potential for leaching of
constituents from ash into underlying soil. The ash and soil SPLP analytical results was
compared to Class GA Standards as found in 15A NCAC 02L .0202 Groundwater Quality
Standards, last amended on April 1, 2013 (2L Standards).

BORINGS OUTSIDE ASH BASIN WASTE BOUNDARY
Borings located outside the ash basin waste boundary are designated as GWA and BG borings.
The GWA soil samples will be used to provide additional characterization of soil conditions
outside the ash basin boundary. Solid phase samples were collected for laboratory analysis
from the following intervals in each boring:
• Approximately 2 feet to 3 feet above the water table
• Approximately 2 feet to 3 feet below the water table
• Within the saturated upper transition zone material (if not already included in the two
sample intervals above)
• From a primary, open, stained fracture within fresh bedrock if existent (bedrock core
locations only)
The boring locations designated as BG borings will be used to evaluate site -specific background
soil quality. Solid phase samples were collected for laboratory analysis from the following
intervals in each boring:
• At approximately 10-foot intervals until reaching the water table (i.e., 0 feet to 2 feet, 10
feet to 12 feet, 20 feet to 22 feet, and so forth)
• Approximately 2 feet to 3 feet above the water table
• Approximately 2 feet to 3 feet below the water table
• Within the saturated upper transition zone material (if not already included in the two
sample intervals above)
• From a primary, open, stained fracture within fresh bedrock if existent (bedrock core
locations only)
The laboratory analyses performed on the GWA and BG samples depended on the nature and
quantity of material collected.
One or more of the above listed sampling intervals were combined if field conditions indicated
they were in close proximity to each other (i.e., one sample was obtained that was applicable to
more than one interval).
INDEX PROPERTY SAMPLING AND ANALYSES
In addition, physical properties of ash and soil were tested in the laboratory to provide data for
use in groundwater modeling. Split -spoon samples were also collected at selected locations
with the number of samples collected from the material types as follows:
• Fill - 5 samples
• Ash - 5 samples
• Alluvium - 5 samples
• Soil/Saprolite - 5 samples
• Soil/Saprolite - immediately above refusal - 5 samples

Select split -spoon samples were tested for:
• Natural Moisture Content Determination in accordance with ASTM D-2216
• Grain size with hydrometer determination in accordance with ASTM Standard D-422
The select split -spoon samples were anticipated to be collected from the following boring
locations:
• Fill — AB-1 S/D (two samples) and AB-2S/D (three samples)
• Ash — AB-4S/D, AB-6S/D, AB-12S/D, AB-15S/D, AB-20S/D, and AL-2S/D
• Alluvium (if present) — AB-1 S/D, AB-2S/D, and SB-1
• Soil/Saprolite (two locations each as stated above) — AB-2S/D, AB-6S/D, AB-12S/D,
GWA-3 S/D, and GWA-6S/D
The depth intervals of the select split -spoon samples were determined in the field by the Lead
Geologist/Engineer.
In addition to split -spoon sampling, a minimum of five thin -walled undisturbed tubes ("Shelby"
Tubes) in fill, ash, and soil/saprolite layers was collected from the above -referenced boring
locations. Sample depths were determined in the field based on conditions encountered during
borehole advancement. The Shelby Tubes were transported to a soil testing laboratory and
each tube was tested for the following:
• Natural Moisture Content Determination in accordance with ASTM D-2216
• Grain size with hydrometer determination in accordance with ASTM Standard D-422
• Hydraulic Conductivity Determination in accordance with ASTM Standard D-5084
• Specific Gravity of Soils in accordance with ASTM Standard D-854
The results of the laboratory soil and ash property determination were used to determine
additional soil properties such as porosity, transmissivity, and specific storativity. The results
from these tests were used in the groundwater fate and transport modeling. The specific borings
where these samples are collected from was determined based on field conditions with
consideration given to their location relative to use in the groundwater model.

Sampling Variances

Variances from Groundwater Assessment Work Plan
Soil and Rock Characterization
Variance
As Proposed
As Completed
Basis for Variance
No.
1
Collect one or more undisturbed
AB-2S/D, AB-5S/DBR, AB-8S/D, AB-
UD samples were not collected due to no recovery
samples according to the
6S/D/BR, AB-9S/D/BR, AB-
of sample media or refusal during sampling attempt.
Groundwater Assessment Work Plan
10S/SL/D, AB-15S/SL/D/BR, AB-
17S/D, AL-1 S/D, AL-2S/D/BR, AL-
3S/D, GWA-1 S/D/BR, GWA-8S/D,
GWA-5S/D, S13-2, S13-5 one or more
UD samples not collected
2
Collect a Kd and/or HFO sample
AB-3S/D, AB-12S/SL/D, AB-14S/D, AB-
UD samples were not collected due to no recovery
according to the Groundwater
15S/SL/D/BR, AB-21S/D, GWA-7S/D,
of sample media or refusal during sampling attempt.
Assessment Work Plan
SB-1 Kd and/or HFO sample not
collected
3
Collect alluvium index parameter
No alluvium index parameter
Alluvium was not present at these locations
samples at boring locations AB-1 and
samples collected
AB-2
4
Collect two index samples in fill
No fill index parameter samples
Fill/soil interface encountered shallower than
material from boring location AB-2
collected
predicted in Work Plan
5
Collect soil/saprolite index parameter
No soil/saprolite samples collected
Soil/saprolite layer did not yield enough sample
samples from boring locations AB-6
quantity for proper analysis
6
Collect ash samples from boring
AB-9S/D/BR, AB-11 S/D no ash
Ash was not encountered at these locations
locations AB-9S/D/BR, and AB-
samples collected
11 S/D
7
Collect index parameter or UD
Index parameter or UD samples
Samples were collected as alternates to locations
samples from locations mentioned in
collected at boring locations AB-
where sample collection failed
Work Plan
3S/D, AB-4S/SL/D, AB-10S/SL/D,
AB-11 S/D,AB-12S/D, AB-
15S/SL/D/BR, AB-18S/D, AB-21 S/D,
and SB-1
8
Collect stained rock at boring
No stained rock fracture samples
No stained rock fractures present at boring location
locations AL-2, GWA-913R, and MW-
collected
14BR
9
Install soil boring S13-6
SB-6 was deleted from the scope of
Uncertainty of location of underground pipes in the
the Work Plan
vicinity of boring location