SW_F_5306-STRUCT-2015_03-13-2015_SP_AC.pdf

hdrinc.com
440 S Church Street, Suite 1000, Charlotte, NC 28202-2075
704.338.6700

March 13, 2015

Mr. Ed Mussler, III, PE, Supervisor
Permitting Branch, Solid Waste Section
Division of Waste Management, NCDENR
1646 Mail Service Center
Raleigh NC 27699
Dear Mr. Mussler,
On behalf of Green Meadow, LLC and Charah, Inc., HDR provides the enclosed Addendum 3
regarding the permit application entitled:
Permit Application, Colon Mine Site, Structural Fill, Charah, Inc., Sanford, North Carolina.
Prepared for Charah, Inc. Prepared by HDR Inc. November 2014. DIN 22354.
This addendum revises the financial assurance calculation and Closure Plan to set the largest area
available for closure area to 31.9 acres. This area matches the largest Cell area that will be
constructed at one time
Financial Assurance Letter
The attached financial assurance letter will replace the letter dated November 11, 2014 currently in
the permit application.
Closure-Post Closure Plan
Section 2.5 of the Closure-Post Closure Plan has been revised to identify 31.9 acres as the largest
area to require closure at one time.
Revisions in narrative documents are shown with deletions struckthrough (struckthrough) and
additions underlined (underlined) along with a change line indicator in the left margin. As requested,
upon completion of the permit application process the revisions will be combined into a final permit
application document for the record.
Please contact me should you have any questions. We hope you find these design enhancements
acceptable and we look forward to discussing them with you.
Sincerely,
HDR Engineering, Inc. of the Carolinas

Michael D. Plummer, PE
Project Manager

Enclosures: Financial Assurance
Closure-Post Closure Plan (revised page only)
This page intentionally left blank.

hdrinc.com
440 S Church Street, Suite 1000, Charlotte, NC 28202-2075
704.338.6700

March 13, 2015
Mr. Norman Divers
Senior Engineer
12601 Plantside Drive
Louisville, KY 40299
RE: Colon Mine Site Structural Fill
Financial Assurance Estimate
HDR Project No. 235691
Dear Mr. Divers,
North Carolina General Statute (NCGS) §130A-309.217 (a) requires that a financial assurance be
established to ensure sufficient funds are available for a structural fill for facility closure, post-
closure care, corrective action, and to satisfy any potential liability for sudden and non-sudden
accidental occurrences. The purpose of this letter is to provide an estimate of the expenses to meet
the financial assurance requirements in NCGS §130A-309.217.
Closure
The cost for closure is provided per acre in the Closure and Post-Closure Plan in the permit
application for the Colon Mine Site Structural Fill. There are two different types of final cover caps
that can be built over the Colon Mine Site Structural Fill. In addition, the final cover cap thickness
varies based on the location of the cap; whether on top of the structural fill or on the side slope of
the structural fill. The highest final cover cap estimate in the Closure and Post-Closure Plan is
$171,300 per acre (for a cap with a geocomposite on the top of the structural fill). The largest cell
area requiring closure is 31.9 acres. Therefore approximately $5,464,470 needs to be set aside in
order to cover the closure costs for the largest area requiring closure at any time at the Colon Mine
Site Structural Fill.
Post-Closure Care
The cost for post-closure care is provided in the Closure and Post-Closure Plan in the permit
application for the Colon Mine Site Structural Fill. The Closure and Post-Closure Plan estimates a
post-closure care cost of $2,916,000.
Corrective Action
The Corrective Action costs assume a one time release, which includes assessment monitoring, an
assessment of corrective measure report/selection of a remedy, and implementation of corrective
action. It is assumed that corrective action occurs in post-closure and that monitored natural
attenuation would be the selected remedy. The total cost for corrective action is estimated to be
approximately $1,383,400. The North Carolina Department of Environment and Natural Resources
Division of Waste Management requires that at least $2 million be set aside for corrective action for
2

solid waste management facilities. Because the state is requiring a permit be obtained from the
Division of Waste Management, HDR has assumed that the $2 million corrective action threshold
also applies to structural fills.
Total
The total amount to be set aside for financial assurance is $10,380,470, as detailed in the
calculation below.
Closure Costs $5,464,470
Post-Closure Costs $2,916,000
Corrective Action Costs $2,000,000
Total Costs $10,380,470

If you have any questions about this cost estimate, please feel free to contact me at (704) 338-
6700.
Sincerely,
HDR Engineering, Inc. of the Carolinas

Michael D. Plummer, PE
Project Manager

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Charah, Inc. | Colon Mine Site – Closure and Post-Closure Plan
Appendix

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Closure and Post-Closure Plan
Colon Mine Site
Structural Fill
Charah, Inc.
Sanford, NC
November 2014
Revised January 2015
Revised March 2015

Charah, Inc. | Colon Mine Site – Closure and Post-Closure Plan
Closure Plan

3

pressure construction equipment meeting the requirements of the project specifications. The
topsoil will be a six-inch thick layer of soil capable of promoting the growth of vegetation. The
total thickness of the final cover shall be at least six feet on the top of the structural fill and at
least four feet on the side slopes of the structural fill.
2.2 Surface Water Runoff and Run-on
Surface water running off the structural fill during and after a rainfall event will be collected and
routed off the cover by erosion control benches and slope drains. Surface water that flows
toward the structural fill from uphill areas (run-on) will be intercepted and channeled away from
the structural fill and final cover surface by diversion channels and perimeter berms.
2.3 Erosion Control
Erosion will be controlled by vegetation, erosion control benches and diversion of run-off.
Vegetation will aid in reducing soil erosion. Benches break the velocity of sheet flow over the
closed structural fill, control development of erosion features before they damage the final
cover, and divert runoff into manageable flow volumes. Sediment laden runoff will be collected
in the sediment basins.
2.4 Dust Control
Dust control during closure construction will be managed as outlined in the Operations Plan and
appropriate for closure construction.
2.5 Estimate of Largest Area to Require Closure
NCGS §130A-309.218 (b) (1) b. requires the Closure Plan to provide an estimate of the largest
area of the structural fill project that will require a cap at any time during the overall construction
period. The largest area requiring closure at any time will be 51.231.9 acres.
2.6 Estimate of Maximum Inventory of Coal Combustion
Products
NCGS §130A-309.218 (b) (1) c. requires the Closure Plan to provide an estimate of the
maximum inventory of CCPs ever onsite over the construction duration of the structural fill. The
structural fill is sized to hold an estimated total of approximately 7.25 million cubic yards of
CCPs in five cells.
2.7 Closure Schedule
NCGS §130A-309.218 (b) (1) d. requires the Closure Plan to provide a schedule for completing
all activities necessary to satisfy the closure criteria. In accordance with NCGS §130A-309.218
(a) (1), cap application will start no later than 30 working days or 60 calendar days, whichever is
less, after CCP placement has ceased. Closure construction is anticipated to take up to a year
to complete. Refer to the Reclamation Timeline in the Earthwork Calculations section for the
anticipated closure schedule.