Duke Mayo Gyp Pad Additional Assessment Work Plan_20190213

4� DUKE
ENERGY
February 13, 2020
North Carolina Department of Environmental Quality
Water Quality Regional Operations
3800 Barrett Drive
1628 Mail Service Center
Raleigh, North Carolina 27699
Attn: Mr. Eric Rice (submitted electronically)
Re: Mayo Steam Electric Plant Gypsum Pad Storage Area
Additional Groundwater Assessment Work Plan
Mayo Steam Electric Plant
10660 Boston Road
Roxboro, North Carolina 27574
Dear Mr. Rice:
2500 Fairfax Road
Greensboro, North Carolina 27407
336-215-4576
Duke Energy is submitting the attached Additional Assessment Work Plan for the Gypsum Pad
Storage Area (GPSA) at the Mayo Steam Electric Plant for your review.
The initial assessment Work Plan for the GPSA was submitted to the Division Raleigh Regional
Office on May 15, 2019, subsequently approved on June 14, 2019.
Initial assessment efforts indicate the presence of CCR related constituents in groundwater
proximate with the GPSA. Two monitoring well clusters are proposed for installation to further
characterize the GPSA on the northwest side. Like the Coal Pile Storage Area (GPSA), the
GPSA is bound on the northwest by internal plant roadways, multiple rail lines, multiple utilities,
and ultimately the ash basin. The southeast area of the GPSA is constrained by plant roads,
underground utilities, overhead conveyors, and ultimately the powerhouse. The CPSA is
adjacent to the southwestern side of the GPSA. The Conceptual Site Assessment for the CPSA
and GPSA will be combined and completed as one report since source characterization
potentially overlaps the area between the areas.
Upon concurrence with this Work Plan, Duke Energy will pursue receipt of necessary permits
for the installation of 6 proposed groundwater monitoring wells, soil investigation, and perform
associated sampling and analysis.
If you need additional information regarding this submittal do not hesitate to call or email, 336-
215-4576 or [e-mail].
Mayo Steam Electric Plant - Page I of 2

Respectfully submitted,
K-`64
Kimberlee Witt, PE
Environmental Services
Attachments: Work Plan for Additional Assessment — Gypsum Pile Storage Area, Mayo Steam
Electric Plant, SynTerra February 2020
ecc: Coal Ash War Room - NCDEQ
Rick Bolich - NCDEQ
Eric Smith — NCDEQ
Scott Vinson - NCDEQ
Steve Lanter — NCDEQ
Eric Rice - NCDEQ
John Toepfer - Duke Energy
Ed Sullivan — Duke Energy
Jerry Wylie — SynTerra
Peggy Altman - SynTerra
Mayo Steam Electric Plant - Page 2 of 2