20150041 Ver 1_Attach H Structural Fills At Clay Mines_20150224

Structural Fills at Clay Mines
As part of Duke Energy's plans to
excavate coal ash from high - priority
North Carolina sites, the company
selected Charah, Inc. to remove
coal ash from the Riverbend Steam
Station in Mount Holly and the
L.V. Sutton Steam Electric Plant in
Wilmington and beneficially reuse
the ash as a structural fill at open -
pit clay mines in Chatham and Lee
Counties, North Carolina.
What is a structural fill?
A structural fill is a material that is
placed and compacted in accordance
with approved design criteria
in order to improve land for an
intended use. Coal ash is a useful fill material due
to its low unit weight, relatively high shear strength,
and ease of handling and compaction. In this case,
coal ash will be used as a structural fill to restore the
Brickhaven Mine in Moncure (Chatham County) and
the Sanford Mine in Sanford (Lee County).
Charah will place the ash in a series of specially
engineered synthetic liners, with the top and bottom
impermeable liners being heat - welded to encapsulate
the ash. The completed structural fill will be covered
with soil. This project will meet all state and federal
standards for a structural fill, including groundwater
monitoring and reporting, and will comply with the
requirements set forth in Sections 4(b) and (c) of the
North Carolina Coal Ash Management Act.
VEGETATIVE STABILIZATION
SOIL COVER
40 MIL HOPE LINER (TE)(TURED)
COAL COMBUSTION RESIDUALS (CCRS)
WASHED #57 STONE WRAPPED WITH
NON -WOVEN GEOTEXTILE
PERFORATED HDPE COLLECTION PIPE
GEOCOMPOSITE DRAINAGE LAYER
60 MIL HOPE LINER (TEXTURED)
GEOCOMPOSITE CLAY LINER
SOILSUBGRADE
111 U37RATWE RiAPI]SES ONL I' - �T
How much coal ash will be used in structural fill
projects at the mines?
Duke Energy's phase one plans call for approximately
900,000 tons of material from Riverbend and 2
million tons of material from Sutton to be used as
a structural fill at the mines. Subsequent phases to
these structural fill projects are likely.
Why were these mine sites selected for structural fill
using coal ash?
The North Carolina Coal Ash Management Act
specifically includes mine reclamation projects in the
list of approved structural fill uses for coal ash. Using
these open -pit clay mines from the brick industry
for structural fills has several advantages, including
the reclamation of previously unusable land, existing
access to rail, and deep layers of impervious clay that
provide additional environmental protection.

Where are the mine sites?
The Brickhaven Mine is in Moncure, an
unincorporated community in southeastern Chatham
County, and the Sanford Mine is in Sanford in
northeastern Lee County. Both mines are in areas
zoned for industrial use.
When will the project start, and what is the
duration?
Duke Energy submitted its plans to the North
Carolina Department of Environment and Natural
Resources (NC DENR) on November 13, 2014. Based
on current estimates, phase one of the structural fill
projects will continue for 18 months after the plans
and associated permits are approved by NC DENR.
Subsequent phases to these structural fill projects
are likely, and the Coal Ash Management Act requires
the closure of basins at the high - priority sites by
August 1, 2019.
How will this project impact local residents and their
quality of life?
Charah makes every effort to be a good neighbor
in its operations. Coal ash will be transported
primarily by rail to alleviate concerns about increased
truck traffic on state roadways.
Additionally, safety is Charah's
foremost priority, and the company
has been recognized repeatedly
by the U.S. Department of Labor, s"1
state agencies including the N.C.
Department of Labor, and industry
organizations for its outstanding
record of employee safety.
What are the economic benefits of
this project?
The project is expected to create
d
up to 60 jobs in Chatham County7'
and up to 40 jobs in Lee County,
depending on operational needs.
Charah plans to invest more than
$10 million in the area for local
subcontractors, suppliers and fuel.
This project also will add to state
and local tax revenues, inclusive
of payroll, property and other
applicable taxes.
How will the restored mine sites be used?
The restored mine sites will be suitable for
commercial development, agricultural use or green
space. Specific plans have not been determined.
Who is responsible for long -term monitoring of the
sites?
Charah will be responsible for long -term
groundwater monitoring and reporting in
accordance with North Carolina state standards and
requirements.
What is Charah's track record, and has the company
successfully done this type of project?
Charah is one of the largest providers of coal
combustion product management and power plant
support services for the coal -fired electric utility
industry. Charah has been operating in North
Carolina since 2001, with 120 employees in the
state and eight current projects. The company uses
the best practices, materials and technology for
structural fills and is nearing completion of a coal
ash structural fill project at Asheville (North Carolina)
Regional Airport.
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