20241031_Narrative_19-08

EIS
ENGINEERING & ENVIRONMENTAL SCIENCE COMPANY
3008 ANDERSON DRIVE.SUITE 102
RALEIGH,NC 27609
[phone]
LETTER OF TRANSMITTAL
Date: October 29, 2024 RECEIVED
To: NCDEQ-DEMLR '7 31 2024
1612 Mail Service Center
Raleigh,NC 27699-1612 LAND QUALITY SECTION
From: T. Patrick Shillington, P.E.
Engineering and Environmental Science Company (E2S)
3008 Anderson Dr., Suite 102
Raleigh, NC 27609
Subject: Brickhaven Mine#2 Tract B (Mining Permit# 19-08)
Mining Permit Modification
Chatham County
Submitted are two (2) copies of the revised mine maps, specifications, and evaluation for
the above referenced project. The revisions were based on the comments from NCDEQ-
DEMLR in a letter dated May 6, 2024.
1. Please clearly identify and label on the mine map all pit boundaries and limits of
excavation. Limits of disturbance do not clearly indicate where mine excavations will
occur. Existing contours are shown on the reclamation map.
The limits of excavation are provided on Sheet 3.
2. The grades shown on the reclamation plan are the same as what is shown on the
erosion control plan. Please include proposed final grades/contours on your reclamation
plan.
The mining operation and reclamation process will occur per the approved plans
and operating conditions. Providing final proposed grades/contours for the life of
the mine is impracticable due to the indeterminate final depths of the mining
operation process. However, an additional Cross-Section has been added to the
reclamation plan indicating the proposed post-mining conditions for the proposed
mining area.

3. The extended berm on the north-eastern edge of the proposed permit boundary does
not address visual screening, or inadvertent access to the site from the adjoining property.
Please provide additional measures, such as extending the proposed berm, to address
visual screening and inadvertent site access.
The berm on the northeastern portion of the site has been extended to prevent
inadvertent access to the site. Also, existing trees are present within the 25'
Undisturbed Buffer along the northern property line to provide visual screening.
4. Please provide a plan or schematic clarifying the 40 ft undisturbed buffer from the
power poles. In addition,please label the easement as non-excavated on the mine maps.
No excavation is proposed within the 100' Progress Energy Easement. Also, a 25'
Undisturbed Buffer is provided adjacent to and north of the easement. A schematic
showing the 40' undisturbed buffer from the power poles is provided on Sheet 1 as
well as the Reclamation Plan.
5. Please remove the two ponds on the southwestern edge of the mine maps,just outside
the permit boundary, which have been filled in and no longer exist per your response to
our last ADI request, received from Engineering & Environmental Science Company,
dated March 8, 2024.
These two ponds have been removed from the mine maps. These ponds are not part
of the mining operation.
6. Please provide more accurate topographic contours, for more accurate site conditions,
which affect the design of sediment basins.
2' Lidar contour data has been provided. The 2' contours generally matched the
drainage patterns of the previously used 5' contours. However, the drainage areas
for the basins were re-delineated and re-designed based on the 2' contours.
7. The detail provided for a stable conveyance for basin inflow into the sediment basins is
inadequate. Discharge device into basin must be designed to handle anticipated volume
and shown in plain view in both the generalized detail and on individual plan sheets.
Additionally, detail must include maintenance requirements for whatever method is used.
The detail for the stable conveyance for basin inflow has been revised (See Sheet 5).
Maintenance requirements are also provided.
8. Please provide adequate space between the sediment basins and the berms to prevent
sloughing from the berms directly into the basins. Waiting for the berms to slough into
the basins to then clean them from the basins is not an acceptable maintenance plan.
A 5' area is provided between the soil berm and the 3:1 (H:V) downward slope to
the bottom of the basins. A general detail indicating this has been provided on Sheet
3.
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9. The Manning's roughness coefficient is too high, which has the effect of lengthening
flow time which reduces required basin size. The issue with the velocity of shallow
concentrated flow appears to come back to the unreasonably high Manning's roughness
coefficient. A value of 0.025 for bare clay soil may be acceptable, but the 0.05 as
proposed is too high.
The basins have been re-designed, and a Manning's roughness coefficient of 0.025
for bare clay soil is now used for the time of concentration calculations
10. Diversion ditches/slope drains are needed at a minimum to direct stormwater runoff
to a well-defined and stable conveyance and into the sediment basins. Slope drains: must
be designed to ensure adequate capacity. Diversion ditches: provide design calculations
for planned channels and diversion ditches. Provide identifiers on the plan to
corresponding calculations. Provide liners/matting to aid the stabilization when the runoff
velocity will exceed 2 ft/sec on bare earth during the 2-year rainfall event that produces
peak runoff. The product(s) selected must have a permissible shear stress that exceeds the
shear stress of the runoff event. If liners/mattings are used provide a plan detail,
construction specifications and maintenance requirements.
Stormwater runoff will generally be directed to the basins via sheet water runoff, or
along the exterior berms.No diversion ditches are proposed.
11. Based on a recent site visit and discussions with Warren Paschal and David Curtis, a
revised design for Basin K is requested. Currently the skimmer is installed high on the
riser structure, potentially inhibiting the skimmer from drawing down the basin per the
approved plan and calculations. The off-site outlet area may have a higher elevation than
the basin which may be the cause of permanent impoundment of water. The baffles are
currently permanently overtopped preventing the intended function of allowing the
sediments to settle out.
The skimmers will be re-installed lower on the existing riser structure. Elevations
for the skimmer installation are provided on the mine drawings.The lowering of the
skimmers by 2.5 ft.will prevent the baffles from being permanently overtopped and
will allow the basin to function as intended.
12. Please update the mine maps with the current owners of all adjoining land and ensure
that they have been properly notified. The parcels to the north and east of the site are
labeled as owned by Chatham Ridge LLC while the Chatham County GIS and tax record
currently indicates that it is owned by VinFast Manufacturing US LLC. To the southeast
are several residential lots. Please add Lisa Maloof, of Parcel #67946, to the mine maps.
Please update parcel #68036 as it is listed under George W. Brown while Chatham
County GIS and tax record indicate that the owner is Tammy Lynn Brown. Please update
the owners of record of the adjoining land with the current owners, Duke Energy
Progress LLC, south and east of Moncure Flatwood Rd, and Green Meadow LLC to the
west.
The adjoining landowner information has been updated based on the Chatham
County GIS information. The permitted acreage for the mine (348 acres) has not
changed since 2014. Notifications were sent to adjoining landowners and the county
6's

official at that time. Since no increase to the permitted acreage is proposed,
notifications have not been sent to the adjacent landowners as part of this permit
modification.
13. Please provide proof, such as copy of the signed return receipts from certified mail,
that all landowners of the land adjoining the proposed modification and chief
administrative officer of each county and municipality have been properly notified.
The permitted acreage for the mine (348 acres) has not changed since 2014.
Notifications were sent to adjoining landowners and the county official at that time.
Since no increase to the permitted acreage is proposed, notifications have not been
sent to the adjacent landowners as part of this permit modification.
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