20210521_LQS_Comments

From:
EEolin, Tamera
To:
Parr, Adam
Cc:
Lentz, Zachary; Hiatt, Levi
Subject:
86-01 Mt. Airy Quarry, WSRO Comments
Date:
Thursday, May 20, 2021 11:57:57 AM
Attachments:
86-01 Mt. Airy Ouarry Mine Inspection 20210514.docx
image001.pno
86-01 DAO Comments 20210506.Ddf
Adam, our combined comments on the application are below:
1. Levi, Zac and others inspected the mine May 11, 2021 and the inspection report is
attached. I -BEAM will be updated for this inspection after Levi returns from vacation.
2. DAQ comments were scanned and are attached.
3. Sue Homewood usually forwards her comments directly to you. Please let me know if
you haven't received her comments.
4. NCWRC recommends a 100-ft buffer to lessen impacts to the Ararat River. This may
impact the mine footprint and proposed measures, so at least another iteration of
review will be necessary.
5. Seeding specifications were also commented on by NCWRC, and would have to be
addressed within the application.
6. Calculations for the sediment basins are based upon 10-year design storms. Redesign
for the 25-yr storm is necessary.
7. The acreage table required to be on the mine map shows 0 acres for sediment ponds
despite several being shown on the plan. It is understood that the permittee has viewed
the sediment ponds as temporary measures that do not need to be included in the
table, but they must be included due to their potential for long-term implementation
and the indefinite timing of their installation and removal.
8. Please elaborate on what discussions have been held with the owner of the 128' wide
powerline easement shown on the plan as it relates to the proposed work in the area.
9. Part B.2. of the application lists minimum features that must be clearly illustrated on the
mine maps. The items below must be shown and labeled on the maps:
a. Initial and ultimate limits of clearing and grading
e. Outline and acreage of all pits/excavations
f. Outline and acreage of all stockpile areas
k. Location and acreage of all planned and existing access roads and on -site haul
roads
m. Location and dimensions of all proposed sediment and erosion control
measures.
10. Part C.1 of the application calls for a detailed description of events for the development
and operation of the mine to be referenced to the mine maps. The response provided
lacks sufficient detail to adequately evaluate the plan and proposed measures. Please
provide detailed sequencing, referencing the particular drainage areas and movement
across the site.

11. Part C.3.b of the application indicates that the operation will not discharge to waters of
the State. This is not accurate since the removal of soil down to the rock is considered
mining and the sediment basin outfalls will discharge to waters of the State. A permit is
required for stormwater discharges (See part C.3.d), and the outfalls must be shown on
the mine maps.
12. Please provide documentation showing that the excavation will not extend below the
water table, as indicated in the application in part C.3.c.
13. Part D.1. of the application, asks for a description of the reclamation plan, design
information, and calls for information to be included on the reclamation map. The
application and mine maps lack clear sequencing for grading, stabilizing, and
demobilizing for reclamation, and a reclamation map has not been provided.
14. The scale for sheet C-10 showing the approximate mine excavation limits is at 1" = 300.'
Please revise this map so that it is shown at a scale no smaller than 1" = 200' as required
by the mining application.
15. The pond shown on sheet C-2 located on the southern area of the site, directly south of
the existing power line easement and directly north of the Ararat River, is within the pit
mining area. Will this pond be dewatered, and at what point will this occur?
16. A 32 acre area within the existing permit boundary is proposed as an overburden area;
please address erosion control for this area.
17. Diversions should be installed along the top of the sediment basin wall directed toward
slope drains to prevent sheet flow over sediment basin slopes greater than 7 feet, such
as along the top of skimmer basins #1 and #6 to direct runoff into both slope drains for
this basin.
18. A diversion ditch is also needed along the top of skimmer basin #2 on the northeast side
to protect the cut slope and direct the runoff to enter the basin on the northwest.
19. 1A diversion ditch is needed along the northwest and southeast sides of sediment basin
#3 to collect runoff in the subdrainage areas below the first baffle, and direct it to enter
the basin above the first baffle.
20. The diversion ditch on the north side of skimmer basin #4 should be extended in a
northeast direction to capture sediment laden runoff from the downstream side of the
ridge and direct it to the basin.
21. The current silt fence detail does not include the strength of the steel posts used for silt
fence and shows the depth of the backfill trench as being 6-inches deep. The steel posts
used for silt fence must be 1.25 Ibf/LF at a minimum, with a minimum length of 5-feet.
The backfill trench for silt fencing needs to be at least 8-inches deep with the post being
at least 2-foot deep. Furthermore, the current detail does not show the maximum
spacing between the steel posts. Please revise the detail to illustrate the above
specifications.
22. The elevation of the top of the riser for sediment basin #3 is 0.14 inches lower than the
water elevation for a 2-yr, 24-hr storm event. The top of the riser should be above this
depth to ensure the skimmer is the only outlet functioning during a 2-yr, 24-hr storm.

Redesign is recommended.
23. Remove silt fence from the emergency spillway of any basin where it's shown.
24. Please clarify if any land -disturbing activity will occur south of the diversions on sheet C-
6; additional measures may be required.
25. Silt fencing typically has a design life of six months. Will the silt fence and stone outlets
be replaced every six months for the life of this mine? Please address.
Please let us know if we may provide additional assistance,
Tamera Eplin, PE
Regional Engineer
Land Quality Section, Winston-Salem Regional Office
Division of Energy, Mineral and Land Resources
North Carolina Department of Environmental Quality
[phone] office
tamera.eplinQncdenr.gov
450 West Hanes Mill Road, Suite 300
Winston-Salem, NC 27105-7407
EQ:>
NORTH CAROLINA i
Department of Environmental Quality
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North Carolina Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19, the Department of
Environmental Quality has adjusted operations to protect the health and safety of the staff
and public. Many employees are working remotely or are on staggered shifts. To
accommodate these staffing changes, The Winston-Salem Regional office is presently
closed to the public, except by appointment only. We are still accepting mail and reviewing
erosion control plans. Temporary modifications to our express review procedures are in
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