1812_DukeMarshall_MonthlyUpdates_FID1809377_20230626

Duke Energy Carolinas LLC, Marshall Steam Station
June 26, 2023
NCDEQ Division of Waste Management (DWM) Solid Waste Section Marshall Steam Station Monthly Update
May 25 through June 26, 2023
Below is the monthly summary for Marshall Steam Station Solid Waste facility and project activities, regulatory submittals and
approvals, and upcoming items.
Facility and Project Activities:
• General:
• No general site updates.
• Dry Ash Landfill (1804-INDUS-1983):
• No general facility updates.
Phase I:
• Area has been stabilized. It is proposed to continue excavating soil from below the final CCR excavation
elevation. The excavated soil would be used as an onsite soil resource for construction projects as needed. It
is proposed that soil would be used within a liner system, or used below a geosynthetic cap.
• Certification for completing closure by excavation is expected to be submitted in 2023 or when borrow
activities and final grading is completed.
Phase II:
• Construction of the geosynthetic cap continues with tree clearing and grubbing at the western toe. Ash
excavation to support construction of the southern stability feature is expected to begin by the end of June
2023.
• FGD Landfill (1809-INDUS-2006):
• No general facility updates.
• Industrial Landfill No.1 (1812-INDUS-2008):
• No general facility updates.
ILF Phase 1 and 2 Operations:
• Normal operations for Phase 1 and Phase 2, Cell 5. Placement of CCR material is primarily in Cell 5.
• The Phase 2, Cell 5 blanket underdrain remains operational.
ILF Phase 2, Cell 6 Construction:
• Pumps and functional testing are expected to be installed and completed by the end of June or early July,
waiting for permanent power to be supplied.
• Other ongoing construction includes electrical work on the riser pad and installation of accessory structures
(e.g., canopy).
ILF Future Phases Area Excavation:
• Excavation and dewatering of CCR in the future phases is ongoing. CCR excavated from this area was placed
in Cell 5.
Groundwater:
• Water levels in 23 piezometers and groundwater monitoring wells in the ILF area continue to be monitored.
The next manual water level measurements will be collected the week of June 26, 2023. Transducers
continue to record data at 1-hr to 4-hr intervals.
Leachate Basin:
• Functional testing of the pump station was completed in June 2023.
• The temporary single walled leachate forcemain line on top of the Structural Fill remains operational; daily
inspections are completed.
• Fusing of the dual walled forcemain is complete. The dual walled forcemain tie in with the leachate basin and ILF
Phase 1 and 2 is schedule to occur late June or early July. NCDEQ will receive a notification when the tie in
activities begin and are completed. The leachate basin will not become operational upon completing the tie in.
• Structural Fill (CCB0031):
• Installation of the closure turf geomembrane and closure turf began installation on March 21, 2023 and continues.
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Duke Energy Carolinas LLC, Marshall Steam Station
June 26, 2023
Installation of the geomembrane and geotextile for all other areas of the cap began installation on April 26, 2023
and continues.
Structural Fill Access Road (CCB0030):
• Excavation of the ash basin continues adjacent to the road. The road is planned for excavation beginning in July
2023.
• A temporary stockpile of clay (for landfill construction) has been placed in a small portion of the Structural Fill
Access Road. The stockpile will be relocated for closure by excavation.
Stability Features (Ash Basin, Structural Fill and Dry Ash Landfill Phase 11):
• Excavation of the dry stacked ash from the Dry Ash Landfill Phase II to support stability feature construction is
expected to begin by the end of June 2023.
• Additional instrumentation (vibrating wire piezometers and inclinometers) were installed in June 2023 at the Dry
Ash Landfill Phase 11 and the Structural Fill to monitor water levels and stability through excavation and
construction.
• Instrumentation continues to be monitored within the vicinity of the stability features.
• Other Ash Basin Closure Projects:
• Continued ash basin dewatering, with current elevation of the pond at approximately 775 NAVD 88.
• Excavation of CCR from the ash basin continues. Excavated CCR is placed in ILF Cell 5.
Regulatory:
• On May 31, 2023, Duke Energy submitted a request to install monitoring instrumentation through the Structural Fill
and Dry Ash Landfill Phase II for construction of the stability features. Approval of the request was received on June
1, 2023.
• On June 12, 2023, Duke Energy submitted the Amended Closure Plan for the Structural fill Access Road. Approval of
the plan was received on June 23, 2023.
• On June 13, 2023, Duke Energy submitted the Dry Ash Landfill Semiannual Groundwater Monitoring Report.
• On June 13, 2023, Duke Energy submitted the ILF Semiannual Environmental Controls Monitoring Plan Report.
• On June 25, 2023, Duke Energy submitted a well abandonment completion report for wells associated with the Dry
Ash Landfill Phase II.
• On June 26, 2023, Duke Energy provided a notification that the dry, stacked ash excavation for the Dry Ash Landfill
Phase II will begin by the end of June 2023.
Upcoming:
• The double walled forcemain section to the ILF LCRS is expected to be tied in by early July. A notification will be
provided when beginning and completing the work.
• Volume 3 (Mechanical, Electrical, and Piping) of the Leachate Basin construction certification report will be submitted
by June 30, 2023.
• Volume 3 (Leachate Removal System) of the Cell 6 construction certification report will be submitted by July 7, 2023.
• The Interim Operations Request to begin placing protective cover in Cell 6 will follow submittal of Volume 3 of the
Leachate and Volume 3 of Cell 6 in July 2023.
• The Q2 2023 Groundwater Conditions Report will be submitted by August 1, 2023.
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