Allen_AmendedClosurePlan_Rev1_AppendixC2_20200731

APPENDIX C2
Borrow Soil Quantities

AECOM
Job Duke Energy — Allen Closure Project No. 60572629 Sheet 1 of 2
Description Soil Borrow Quantities Computed by MLM Date 7/13/20
Closure by Excavation Checked by AMC Date 7/13/20
The purpose of this memorandum is to summarize the results of the borrow soil demand quantity
calculations for closure -by -excavation (CbE) of the Allen Steam Station Ash Basins. As the design
is further developed, these quantities will be refined. The quantities included herein are to be
considered a rough -order -of magnitude.
Soil borrow demand quantities that were calculated at this stage of the design include the
following:
- Fill: Backfill in CbE areas following removal of CCR materials to promote surface water
drainage and to stabilize these areas.
Cut: Breaching the RAB North Dike, AAB East Dike, AAB North Dike.
Required borrow soil volumes were calculated using AutoCAD. The net cut balance of borrow soil
is represented as a soil surplus. This analysis shows that sufficient quantities of soil borrow are
anticipated to be generated by the project; however, additional material, if necessary, is assumed
to be available in other locations on the Duke Allen property.
The estimated borrow soil demand quantities are summarized in Table 1 below, along with
additional assumptions and notes.

AECOM
Job Duke Energy — Allen Closure Project No. 60572629 Sheet 2 of 2
Description Soil Borrow Quantities Computed by MLM Date 7/13/20
Closure by Excavation Checked by AMC Date 7/13/20
Table 1— Summary of Borrow Soil Cut/Fill Quantities
Retired Ash Basin (RAB)
Description
Quantity
Unit
Notes
Cut
65,000
CY
• 65K CY cut for breaching RAB North Dike
Fill
194,000
CY
• 194 CY fill for backfill of CbE areas
RAB soil deficit
128,000
CY
• Cut minus fill
Active Ash Basin (AAB)
Description
Quantity
Unit
Notes
Cut
521,000
CY
. 374K CY cut for breaching AAB East Dike
• 147K CY cut for excavation of AAB North Dike
Fill
156,000
CY
. 156K CY fill for backfill of CbE areas
AAB soil surplus
365,000
CY
• Cut minus fill
Total Soil Surplus
(RAB + AAB)
237,000
CY
Assumptions:
1. No adjustments were used for material swelling, shrinkage, settlement, and waste.
2. Material quantities for construction of the proposed Ash Basin Landfill (ABLF), North Starter Landfill
(NSLF) and South Starter Landfill (SSLF) are excluded.
3. Material quantities for backfill of CbE areas based on one foot of cut and soil replacement in areas outside
of proposed landfill boundaries, and within the CCR Unit Boundary.
4. Material quantities for construction of stormwater channels and ponds associated with Ash Basin closure
are excluded.