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HomeMy WebLinkAbout6512_Duke_Sutton_Cell5SubgradeCertification_DIN27695_201704271300 Mint Street, Suite 300 Charlotte, North Carolina 28203 PH 704.227.0840 www.geosyntec.com GC6198/Subgrade Certification - Cell 5 25 April 2017 Mr. Stephen Williams Duke Energy Corporation 801 Sutton Steam Plant Road Wilmington, NC 28401 Subject: Subgrade Certification Letter Sutton CCR Landfill - Cell 5 Wilmington, North Carolina Dear Mr. Williams: Geosyntec Consultants of North Carolina, P.C. (Geosyntec) prepared this letter to comply with Condition No. 9 found in Attachment 2 of the Permit to Construct No. 6512-INDUS-2016 for the Sutton CCR Landfill located in Wilmington, North Carolina. Condition No. 9 states, “A licensed geologist must report any pertinent geological feature(s) exposed during phase or cell excavation. Prior to placing any landfill liner, the geologist must submit to the Section Hydrogeologist a written report that includes an accurate description of the exposed geological feature(s) and effect of the geological feature(s) on the design, construction, and operation of the cell, phase, or unit.” OVERVIEW OF CONSTRUCTION OBSERVATION The earthworks construction activities were performed by Glover Construction (Glover) starting on 16 February 2017 and were substantially completed on 14 April 2017. Mr. John Carruth of Geosyntec served as the designated representative and was on site to observe the construction activities under the direction of the undersigned. CERTIFICATION Surficial sands and the Cretaceous Peedee Formation form part of the borrow pit at the ST Wooten Property, which is adjacent to landfill area, and are very similar in nature. There are no significant confining units between the two formational units in this area. Fill material was excavated from the borrow pit at the ST Wooten Property to bring the Cell 5 area up in elevation from between five and eleven feet; no excavation occurred in the Cell 5 area. Mr. Stephen Williams 25 April 2017 Page 2 GC6198/Subgrade Certification - Cell 5 As expected, the soils excavated in the borrow pit to obtain structural fill for placement in Cell 5 corresponded to a light brown to tan, fine to medium sand. The observed geological features will not have any adverse effect on the design, construction, and operation of Cell 5. If you have any questions or require additional information, please do not hesitate to contact the undersigned. Sincerely, Beau Hodge, P.G. Principal Geologist NC License No. 1243 C. Fabian Benavente, P.E. Senior Engineer