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HomeMy WebLinkAbout3612_Allen_ModifiedClosurePlan_Rev2_AppendixC2_FID1897219_20230731APPENDIX 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.