3619_DukeAllenNSLF_GeoSubgradeObReport_FID1714916_20220727

(' DUKE
ENERGY-.
July 27, 2022
North Carolina Department of Environmental Quality (NCDEQ)
Division of Waste Management (DWM)
Solid Waste Section (the Section)
1646 Mail Service Center
Raleigh, North Carolina 28778
Attn: Ms. Sarah Moutos
Re: Geological Subgrade Observation Report - North Starter Landfill (NSLF)
Reference No.: 3619-INDUS
Allen Steam Station
Gaston County
Dear Ms. Moutos,
526 S. Church Street
EC13K
Charlotte, NC 28202
In accordance with Condition 7 of Attachment 2, Part I of the Permit to Construct the Allen Steam Station
North Starter Landfill (NSLF) 3619-INDUS-2021 issued by the Section on June 11, 2021, Duke Energy is
submitting the enclosed Geological Subgrade Observation Report. As required, the field observations were
conducted and the report prepared under the direction of a North Carolina Licensed Geologist.
This information is only being provided electronically, but hard copies are available upon request. If you
have any questions or comments regarding this submittal, please contact me at Courtney.Murphv@duke-
energy.com or [phone].
Respectfully submitted,
&Zklyw-ff"
Courtney W. Murphy, P.G.
Environmental Services
Enclosures: Geological Subgrade Observation Report — North Starter Landfill (NSLF), Allen Steam
Station, Gaston County, NC, (AECOM, July 20, 2022)
Cc: Jordan Russ — NCDEQ
Elizabeth Werner —NCDEQ
Claire Osborn — NCDEQ
Tyler Hardin — Duke Energy
Melonie Martin — Duke Energy
Ashley Healy — Duke Energy
Kyle Baucom — Duke Energy
Henry Duperier— Duke Energy
Page 1 of 1

AECOM
Duke Energy
400 S. Tryon Street
Charlotte, NC 28202
AECCM
5438 wade Park Boulevard
Suite 200
Raleigh, NC 27607
aecom.com
July 20, 2022
Geological Subgrade Observation Report — North Starter Landfill (NSLF), Allen Steam Station, Gaston County, NC
Dear Mr. Pulley,
AECOM prepared this report to comply with Condition 7 of Attachment 2, Part I of the North Carolina Department of
Environmental Quality (NCDEQ), Division of Waste Management, Solid Waste Section Permit to Construct for the
Duke Energy Carolinas (Duke) Allen Steam Station North Starter Landfill (NSLF) 3619-INDUS-2021 (herein referred
to as the Permit) located near Belmont in Gaston County, North Carolina.
Condition 7 of the Permit states, "A Licensed Geologist must report any pertinent geological feature(s) exposed during
phase or cell excavation. Prior to placing any landfill liner, the geologist must submit to the Section Hydrogeologist a
written report that includes an accurate description of the exposed geological feature(s), subsurface soil condition,
and the effect of the geological feature(s) on the design, construction, and operation of the cell, phase or unit."
Observations
AECOM performed site visits to observe various areas of landfill excavation subgrade on October 14, 2021,
November 10, 2021, March 15, 2022, and June 1, 2022. Observations were conducted to determine if any pertinent
geological feature(s) were exposed within the limits of the NSLF prior to placement of liner materials, in accordance
with Condition 7 of the Permit, stated above. Mr. Shaun Becker conducted the observations on October 14, 2021,
November 10, 2021, and March 15, 2022, under the direction of Dr. Peter Thibodeau, PhD, PG, a North Carolina
licensed Professional Geologist. Dr. Thibodeau conducted the final and comprehensive observations on June 1, 2022.
Representative photos of the general areas observed during the site visits are included in Attachment A.
Findings
Based on the observations made by AECOM during the site visits noted above, soils exposed at the surface in the
NSLF were consistent with residuum soils, as described in AECOM's Geological and Hydrogeological Report, Allen
Steam Station, CCR Closure Landfill Units (3619-, 3620-, and 3621-1NDUS), dated November 3, 2020. The observed
surface material primarily consisted of reddish brown silty clay residuum. No bedrock outcrops were observed within
the NSLF excavation area during the aforementioned site visits.
During the site visits noted above, AECOM did not observe geological features anticipated to have adverse effects on
the design, construction, or operation of the NSLF. This report will be updated if any pertinent geological features are
exposed during the removal of the final approximately 6 to 12 inches of soil layer.
Qualifications
This report includes findings based on the information available at the time it was prepared. It should be noted that
possible variations in stratigraphic characteristics and groundwater conditions may become evident during
construction and/or following further excavation activities in and about the construction. These variations could alter
the recommendations made before that information was available.
aecor.com
112

AECOM
The recommendations provided herein should not be used for other projects or purposes. Conclusions made from
data generated from these recommendations by others are the sole responsibility of the party thereof. The services
provided during the execution of this investigation are consistent with the level of care and skill ordinarily exercised by
professional consultants performing a similar scope of work. No other representation is intended.
If you have any questions or require additional information, please do not hesitate to contact the undersigned.
Sincerely,
Peter M. Thibodeau, PHD, PG
Principal Geologist
AECOM
T: 919.461.1515
E: [e-mail]
Attachment:
Attachment A. Representative Site Photos
z
Jay Mokotoff, PE, PMP
Engineer of Record
AECOM
T: 216.272.2275
E: [e-mail]
aeccm.com
212

Attachment A. Representative Site Photos

Geological Subgrade Observation Report
North Starter Landfill (NSLF), Allen Steam Station, Gaston County, NC
October 14, 2021
Location: North Starter Landfill (NSLF)
Direction: South
Description: Exposed subgrade, north
finger area
November 10, 2021
Location: North Starter Landfill (NSLF)
Direction: North
Description: Exposed subgrade,
northern and central portions of the
NSLF

Geological Subgrade Observation Report
North Starter Landfill (NSLF), Allen Steam Station, Gaston County, NC
November 10, 2021
Location: North Starter Landfill (NSLF)
Direction: Northwest
Description: Exposed subgrade, north
finger area
November 10, 2021
Location: North Starter Landfill (NSLF)
Direction: Northeast
Description: Exposed subgrade,
northern and central portions of the
NSLF

Geological Subgrade Observation Report
North Starter Landfill (NSLF), Allen Steam Station, Gaston County, NC
March 15, 2022
Location: North Starter Landfill (NSLF)
Direction: North
Description: Exposed subgrade,
southern portion of the NSLF
June 1, 2022
Location: North Starter Landfill (NSLF)
Direction: North
Description: Exposed subgrade,
comprehensive NSLF area

Geological Subgrade Observation Report
North Starter Landfill (NSLF), Allen Steam Station, Gaston County, NC
June 1, 2022
Location: North Starter Landfill (NSLF)
Direction: Southwest
Description: Exposed subgrade,
comprehensive NSLF area. Mounding
of excavated dirt from trench
June 1, 2022
Location: North Starter Landfill (NSLF)
Direction: West
Description: Exposed subgrade,
comprehensive NSLF area
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