3612_Duke_Allen_CompactModReq_DIN26763_20160926

526 South Church Street:
Mail Code EC13K
Charlotte, North Carolina 28202
704-382-4761

September 19, 2016

North Carolina Department of Environmental Quality
Division of Waste Management
Solid Waste Section
2090 U.S. Highway 70
Swannanoa, North Carolina 28778

Attn: Mr. Larry Frost

Re: Retired Ash Basin (RAB) Ash Landfill Compaction Modification Request
Permit No.: 3612-INDUS
Allen Steam Station
Gaston County
Belmont, North Carolina 28012

Dear Mr. Frost,

As discussed via phone conversation on September 7, 2016, Duke Energy requests approval for
modification to the intermediate cover compaction specification for exterior slopes at Allen Steam
Station’s RAB Ash Landfill (Permit No. 3612-INDUS). The requested modifications are to revise the
minimum compaction requirement for intermediate cover soil from 95 percent of Standard Proctor
(ASTM D 698) maximum dry density to 90 percent and to revise the moisture content for intermediate
cover soil from within 5 percent to within 3 percent of the material’s optimum moisture content; this
requirement is found in Section 2.3 of the Operations Quality Assurance Plan located in the Operations
Plan – Revision 7, Duke Energy Carolinas, LLC – Allen Steam Station, Retired Ash Basin (RAB) Ash
Landfill – Phase 1, Permit No. 3612, Gaston County, Belmont, North Carolina. The requested
modifications to this section are shown below by an underline.

2.3 QA Field Testing
QA field testing shall be performed to monitor the compaction and moisture conditioning during
waste placement. Waste shall be compacted to a minimum 95 percent of its Standard Proctor
(ASTM D 698) maximum dry density, and intermediate cover soil shall be compacted to a minimum
90 percent of its Standard Proctor (ASTM D 698) maximum dry density. Compacted moisture
content of waste shall be within 5 percent of the material’s optimum moisture content, and
compacted moisture content of intermediate cover soil shall be within 3 percent of optimum moisture
content as determined by ASTM D 698.

Duke Energy proposes to revise this section of the Operations Plan to include the above requested
modifications during the next Permit amendment or modification. If there are any questions regarding this
request, please contact me at [phone].

Respectfully Submitted,
Sean DeNeale
Environmental Services
Cc (via e-mail): Ed Mussler, NCDEQ
Kyle Baucom, Duke Energy
Scott Harris, Duke Energy