Sutton Confirmation of Excavation Requirements_20190211

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health, & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental QuaW
February 11, 2019
Subject: Confirmation of Excavation Requirements for the 1971 Basin
Dear Mr. Draovitch:
The purpose of this letter is to confirm excavation requirements are being met in the L.V. Sutton
Energy Complex 1971 Basin. On December 1, 2017, the North Carolina Department of
Environmental Quality (DEQ) received the L. V Sutton Electric Plant Coal Ash Excavation Plan
2017 Update. On March 9, 2018, DEQ gave approval of the Excavation Soil Sampling Plan
component of the plan along with direction to follow the "Coal Combustion Residuals (CCR)
Surface Impoundment Closure Guidelines for Protection of Groundwater" - November 4, 2016
and the additional guidance provided in the email from Steve Lanter to John Toepfer dated June
14, 2017 and titled, Sutton 1971 Ash Basin - Bottom of Ash Determination - June 2017.
Duke Energy submitted the 1971 Basin Closure Investigation Report, L. V Sutton Energy Complex,
Wilmington, North Carolina that includes coal ash visual confirmation data and soil analytical
sample results. Figure 3 of this report depicts the anticipated elevations the dredging would reach
to complete excavation based on field data. Documentation of the bathymetry of excavation after
completion of dredging was promised by Duke Energy in the January 10, 2018 correspondence to
DEQ titled, L. V. Sutton Energy Complex - 19 71 Ash Basin Documentation for Closure.
The DEQ has reviewed documentation provided by Duke Energy to assess completion of closure
requirements at the subject basin. DEQ concurs that the data provided in the 1971 Basin Closure
Investigation Report, L. V. Sutton Energy Complex, Wilmington, North Carolina meets the
objectives of sample collection and analysis consistent with recommended technical direction
outlined in DEQ's CCR Surface Impoundment Closure Guidelines for Protection of Groundwater.
DEQ accepts the interpretation of unanticipated site conditions that resulted in dredging refusal
are related to localized lithified sandstone beds in the Pee Dee Formation as documented in the
Memorandum Subsurface Conditions at the Bottom of the 1971 Ash Basin, L. V. Sutton Energy
Complex, Wilmington, North Carolina dated January 9, 2019.
North Carolina Department of Environmental Quality I Division of Water Resources
J/ 512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
•,a v
919.707.9000

Based on our review, DEQ accepts that the data and information provided to date concerning
excavation activities at the 1971 Basin meets the objectives of soil closure guidelines that are
protective of groundwater and that unanticipated subsurface site conditions that were encountered
are adequately documented. In order to complete documentation of the 1971 Basin excavation,
DEQ requests submittal of a technical memorandum to summarize excavation activities that will
include:
• Revised estimated volume of coal ash that was stored in the basin, and a
• Revised base of excavation elevation map showing areas of dredging refusal.
Soil and groundwater samples that were collected during the excavation activities shall be
incorporated into the geochemical and transport models that shall be included in the upcoming
Corrective Action Plan.
If you have any questions, please feel free to contact Geoff Kegley at (910)-796-7215 or Steve
Lanter at [phone].
Sincerely,
J knRisg �,Chief
Animal Feeding Operations and
Groundwater Section
r---. )
Edward F. Mus:ler III, P.E.
Chief, Solid Waste Section
Division of Waste Management
cc: WIRO WQROS Regional Office Supervisor
Ellen Lorscheider - Division of Waste Management
WQROS Central File Copy