4117_A1SandrockCDLF_MSEwall_App_Incompleteness_DIN28647_20171128

1
Chao, Ming-tai
From:Chao, Ming-tai
Sent:Tuesday, November 28, 2017 1:46 PM
To:'Garrett, David'
Cc:Mussler, Ed
Subject:RE: [External] A-1 Sandrock MSE wall
Attachments:Draft_4117_A1SandrockCDLF_MSEwall_App_Incompleteness_DIN28647_2017##.docx
Hi David:

As promised, attached please find the draft letter pertaining concerns from our end about the proposed MSE
wall construction at A-1 Sandrock C&DLF. The draft letter is serving as a tool for both sides to discuss in the
upcoming meeting and to reach some degree of consensuses about the wall construction and long-term
operations. Please contact me if you have any question of the draft comments. Have a wonderful day.

Ming Chao
Ming-Tai Chao, P.E.
Environmental Engineer
Permitting Branch, Solid Waste Section
NCDEQ, Division of Waste Management
(Mailing Address)
1646 Mail Service Center
Raleigh, NC 27699-1646

(Street Address)
Green Square, 217 West Jones Street
Raleigh, NC 27603
Tel. [phone]
[e-mail]
http://portal.ncdenr.org/web/wm/sw

E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties.

From: Chao, Ming‐tai  
Sent: Tuesday, November 28, 2017 11:08 AM 
To: 'Garrett, David' <[e-mail]> 
Cc: Mussler, Ed <[e-mail]> 
Subject: RE: [External] A‐1 Sandrock MSE wall 

HI David:

The meeting is set on schedule. Ed is reviewing the “comment” letter right now. After the letter is approved, I
will email it to you as discussion topics/agenda for the upcoming meeting so your side can respond, rebut,
rebuke, or discuss the solutions for the concerns.
2

Ming Chao
Ming-Tai Chao, P.E.
Environmental Engineer
Permitting Branch, Solid Waste Section
NCDEQ, Division of Waste Management
(Mailing Address)
1646 Mail Service Center
Raleigh, NC 27699-1646

(Street Address)
Green Square, 217 West Jones Street
Raleigh, NC 27603
Tel. [phone]
[e-mail]
http://portal.ncdenr.org/web/wm/sw

E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties.

From: Garrett, David [mailto:[e-mail]]  
Sent: Tuesday, November 28, 2017 9:58 AM 
To: Chao, Ming‐tai <[e-mail]>; Mussler, Ed <[e-mail]> 
Subject: [External] A‐1 Sandrock MSE wall 

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Checking to verify we’re still on schedule for a meeting on December 6 at 9 o’clock, your offices.     

David Garrett, PG, PE
Senior Engineer
Direct: 919-765-0070
Mobile: [phone]
www.woodplc.com

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Wheeler Environment & Infrastructure, Inc. (License #F-1253), a wholly owned subsidiary of John
Wood Group, plc. 

3

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ROY COOPER Governor MICHAEL S. REGAN
Secretary MICHAEL SCOTT
Director
Solid Waste Section

##, 2017 Mr. Ronnie E. Petty III A-1 Sandrock, Inc
2901 Bishop Road
Greensboro, NC 27406 Subject: (DRAFT) Determination of Completeness for a Permit Application A-1 Sandrock Construction and Demolition Debris Landfill (C&DLF)
Guilford County, North Carolina,
Permit No. 4117-CDLF-2008, Document ID No. (DIN) 28647 Dear Mr. Petty:
On September 29, 2017, the Solid Waste Section (SWS), Division of Waste Management
(DWM) received a permit application titled as “MSE Wall Permit to Construction and Facility Plan for A-1 Sandrock C&D Landfill (4117-CDLF-2008) Phase 2B (the Application) dated September 14, 2017. The Application is on behalf of A-1 Sandrock, Inc. prepared by AMEC Foster Wheeler Environmental & Infrastructure, Inc. (AMEC Foster Wheeler). Fitzpatrick
Engineering Associates (FEA), contracting A-1 Sandrock, Inc. designs the mechanically
stabilized earth wall (MSE wall). Pursuant to North Carolina General Statute (N.C.G.S.) 130A-295.8(e), the SWS conducted a review of the Application and determines: A. The Application is a new facility application, and the permit fee is required. It is evident
that the increment of the final gross capacity of the C&DLF, upon completing all four
stage walls around the landfill unit as described in the Facility Plan, will be ten percent
(10%) more than the originally approved one (2,240,000 cubic yards). This results in a
substantial amendment to the existing permit per N.C.G.S. 130A 294(b1), and the landfill
facility is considered a “New Facility” as defined in N.C.G.S. 130A-295.8(b)(1a).
Therefore, A-1 Sandrock, Inc. must pay the fee of $550 dollars, which is 10% of the
annual permit fee according to N.C.G.S. 150A 295.8(d2).

The fee of $550 dollars was received on October 16, 2017, and the SWS thanks A-1
Sandrock, Inc. for promptly sending the fee.

B. The Application states that the MSE wall design is according to the National Concrete
Masonry Association and the Federal Highway Administration (FHWA) methodology.
But the field inspection and performance monitoring, portions of the guidance documents
published by above-mentioned agency or trade organization are neither not referenced
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 2 of 18

nor appending to the Application. Without adequately and sufficiently conducting the
field inspection and performance monitoring is conclusively determined as the culprits of
the wall failure either partially or totally in the past. Please provide a state-of-art the field
inspection and performance monitoring plan for the wall construction and post-
construction performance monitoring in the revised Application.

C. The Application is incomplete. The Application requests an approval of new facility plan
of the landfill without changing the approved landfill gross capacity of 2,240, 000 cubic
yards (CY); gross capacity is defined in North Carolina Solid Waste Management Rule
(Rule) 15A NCAC 13B .0537(e)(2)(B). However, the Application only provides the first
stage MSE wall to enhance landfill operations and fails providing the comprehensive
landfill development which comprises four-stage walls. The Application fails to define
the comprehensive development of the C&DLF unit in the Facility Plan and to provide
completed plans associated with landfill engineering design, construction, operations, and
closure and post closure cares for each of the proposed MSE Wall, which are provided in
the comments below. Because the Application doesn’t include all required components
required by the Rules 15A NCAC 13B .0531et seq., the SWS determines that the
Application is incomplete. Pursuant to N.C.G.S. 130A-295.8(e), the SWS notifies A-1
Sandrock, Inc. that the following components stated below are required to complete the
application. Please be advised that a determination of completeness means that the
application includes all required components but does not mean that the required
components provide all the information that is required for the DWM to make a permit
decision on the application.

Facility Plan 1. The update Facility Plan must be prepared according to Rule 15A NCAC 13B .0537.
The submitted plan should be expanded to define the comprehensive development of the
landfill unit after each of the proposed stages of MSE walls are completed. If the content
in the previously approved plan is not changed, the minimum components of the updated
plan include the operation capacity and the estimate operating life at each stage of Stage
1 through 4, total gross capacity of the landfill, the active life of the landfill unit, soil
sources and quantity for covers (weekly cover and final cover system) and the wall
construction at each stage. The Facility Plan drawing(s) should pertain and present the
update facility plan information of the comprehensive landfill development for each of
the proposed stages of MSE walls are completely constructed.

2. Local government approval.
i. The increment of the proposed gross capacity of the C&DLF after four-stage
walls are completely constructed will be ten percent (10%) more than the
originally approved one. This increment will trigger the Substantial Amendment
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 3 of 18

to the Permit as defined in N.C.G.S. 130A 294(b1)(1)a.2; therefore, A-1
Sandrock, Inc. must complete a local governmental approval processes according
to 130A 294(b1)(4) and Rule 15A NCAC 13B .0536(c)(11).

ii. Additionally, the ten-year-term Franchise Agreement between A-1 Sandrock, Inc.
and Guilford County, North Carolina will expire on October 03, 2023, but the
service life expectance of the C&DLF will substantially last for decades after the
franchise term expires if the MSE walls are constructed. Pursuant to N.C.G.S.
130A 294(a2) & (a3) [Session Law 2017-211 Senate Bill 16], A-1Sandrock may
want to request Guilford County an approval of a new or extension of the existing
Franchise Agreement to preserve the proposed long-term landfill capacity.

iii. The landfill facility is in the Deep River Reservoir watershed (Section 5.1.2). The
proposed MSE wall is designed to permanently retain C&D wastes, and the
proposed Stage 1 wall alignment will be located approximately several hundred
feet away from Hickory Creek, a tributary of the Deep River Reservoir watershed.
The waste volume will increase significantly than the originally approved one due
to the wall height of about 40 feet above the existing grade. Should the wall fail,
the wastes likely roll into the immediately adjacent Sediment Basin # 1 and
Hickory Creek. Therefore, A-1 Sandrock, Inc. shall officially contact Guilford
County Department Planning and Development, Watershed Protection and
Stormwater Management or a government agency (such as Land Quality Section,
Dam Safety) which has the jurisdiction over the creek and watershed to determine
if an environmental impact study or remedial/response plan are required due to
the high wall retaining solid wastes. The approved document(s) must be a portion
of the Application.

3. (Section 1.2) Please address the following concerns:
i. In comparison with the approved waste footprint on the Facility Plan drawings of
the approved permit application, the waste foot print of the C&DLF shown on
Drawings E3 & E4 expands southwestward and encroaches/includes the areas on
the south side of the Sediment Basin # 1. The new encompassed area is not
approved waste footprint. If the change of waste footprint is approved by the
local government, A-1 Sandrock can submit the revised Facility Plan and new
waste disposal boundary for an approval; otherwise, revise the Drawings E-3 &
E-4 accordingly.

ii. The construction of Stage 1 MSE wall may impact/disturb the area on the west
side of the existing haul road. The Erosion and Sediment Control Permit issued
by the NC Land Quality Section may be subjected to modification. If the permit
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 4 of 18

modification deems required, the modified Erosion and Sediment Control Plan
should be appended to the Application.

4. (Section 1.2.2) Please address the following concerns:
i. This subsection states that “It is NOT anticipated that each wall increment beyond
the first lift (assumed 12 feet according to the narrative in this subsection) will
requires individual permitting by the SWS.” This statement or proposal violates
the Rules 15A NCAC 13B .0541 and .0201(d)(2). The Permit Approval To
Operate will be issued only if the rule-required CQA Report for that lift wall
section is reviewed and approved by the SWS. Please revise the statement
according to the rule requirements.

ii. A-1 Sandrock, Inc. intends to vegetative the exterior side the MSE wall
(vegetative facing) as described in this subsection.
a. What kind/type of vegetation is to be used for the wall facing unit? Should the
Technical Specification include the installation, establishment, replacement,
and long-tern cares of the vegetative facing unit of the wall?
b. Should the maintenance and care of the vegetation be a portion of the
Operations Plan and Post-Closure Care Plan?

5. (Section 1.3.3 or Section 2) Please provide the following supplemental documents to the
summary of subgrade soil stratifications and related strengths.
i. The drawing(s) to show locations of soil borings (with identifications) relative the
alignment of Stage 1 wall. The data (boring logs) of these selected soil borings
used for the MSE wall design must be appended to the Application.

ii. The drawing(s)/profiles to summarize
a. Soil and rock stratification,
b. Engineering character and strength,
c. Groundwater levels based on the results of subsurface investigation of the
selected soil borings for wall design and historical groundwater well
information.

iii. The reference(s)/document(s) used to generate the summary of subsurface
investigation.

6. (Section 1.3.4) For long-term and comprehensive landfill planning, the soil volume
analysis should estimate the quantity of soil to be used for landfill operations (rule-
required covers) and for wall construction at all four stages (must be met the
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 5 of 18

requirements in Appendix 3 of the Engineering Plan). Please address the concerns
below:
i. The detail calculations of the soil volume for constructing each of the four-stage
wall. The required soil quantity should be consistent to the operational sequence
stated in Section 1.2.2.

ii. The soil borrow location (on-site or off-site) and the AutoCAD calculations of
borrow volumes. If the Phase 3 (as described in Section 1.2.2) the landfill base
grade of the proposed Phase 3 of the C&DLF unit shall be submitted to the SWS
for a review and approval.

Engineering Plan
7. To integrate the proposed MSE wall into the landfill as a unit, it is imperative to design
leachate and stormwater separation devise/structure and/or a leachate collection/removal
system in the life cycle of the landfill for the following condition as mentioned in
Appendix 3 of the Application. The narratives of the storm water and leachate separation
and disposal approaches in accompany with detail drawings must be provide in the
Engineering Plan.

i. Stormwater separation devise/structure. This design and construction of this
structure must consider the approaches to prevent building up hydrostatic pressure
behind the wall (the wall area intimately contacts the waste) or “back drainage
zone design” and to facilitate internally drainage of any surface water and the
percolation through the wall material (the long-term permeability evaluation of
earthen material in the soil-reinforce zone) as recommended by FEA in Appendix
3. The design must conclude the following parameters which must be
incorporated into the CQA Plan and Technical Specification of the Application.
The minimum parameters are factor of safety, flow rate, thickness and hydraulic
conductivity or transmissivity for the proposed drainage material/medium, piping
size and material (if applicable), the outlet/exit design including energy
dissipater(s).
a. While the Stage 1 wall is constructing and the landfill (Phase 1 is inactive
and Phase 2 active) is operating.
b. After wall is completed but not reaching the final height and the first
waste load is placed to the landfill cell. The disposal sequence must also
be illustrated in the Engineering or Operation Plan drawings.
c. After the wall is reached final height and waste is placed above the height
of the perimeter drainage ditches.

Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 6 of 18

ii. If the installed stormwater and surface water measures can’t properly separate
from the waste disposal activities which generates leachate as defined in NCGS
130A-290.a(16a), the leachate collection and removal system and storage unit
must be properly designed and operated. The details of the design, construction,
operations, and closure and post-closure cares of the leachate collection and
removal system must be adequately and sufficiently addressed in the Application.

8. Building Code Requirements. A-1 Sandrock must contact the City of Greensboro (the
City) and/or Guilford County (the County) to request if the proposed wall design and
construction are required a local building permit. The written request and responses from
the local governments must be appended to the Application. Any building permit
requirements must be appended to the Application as well.

9. The Engineering Plan must provide or establish the criteria of acceptable displacement or
deformation of the constructed MSE wall [the lateral movements (direction along the
wall alignment – left to right and direction perpendicular to the wall - front to back) and
vertical movement – up (heave) or down (settlement) directions]. The instrumentation(s)
for the specified monitoring elements and triggering must be specified. The criteria as
the trigging of the emergency response plan shall be incorporated into the routine
inspection and monitoring activities (Comment Nos. B & 12, 34, 40, & 53) throughout
the landfill life (both active and post-closure periods).

10. The Engineering Plan should include a cost estimate to construct the MSE wall; the
breakdown cost, total cost, and unit cost per wall facing unit ($ per square feet) should be
available, which will be used as the basis to establish Financial Responsibility
(Comment No. 54) including both Financial Qualification and Financial Assurance of
the landfill (N.C.G.S. 130A-295.2).

11. The MSE wall design (in Appendix 3) is based on the data in Appendix 2 generated by
A-1 Sandrock, Inc. However, the data in Appendix 2 is collected for the landfill design
and not directly from the sub-surface investigations along the proposed wall alignment.
The geotechnical testing on soil samples (or confirmation testing results) from borings
along the proposed Stage 1 wall alignment should be conducted prior to wall
construction; the testing results must be used to compare the ones used in design in
Appendix 3. Adjustment or redesign a portion of or the entire walls may be warranted by
a professional engineer if the design parameters based on the confirmation soil testing
results vary significantly (as requested by FEA – Sections 2.1, 3.0 & 6.0, Appendix 3 of
the Engineering Plan). Therefore, A-1 Sandrock, Inc. should prepare a subsurface
investigation plan and soil testing program (the program), which should be appended to
the Engineering Plan.
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 7 of 18

i. The program must be prepared according to building codes or the FHWA
guidance for subsurface investigations for design/construction of a retaining wall
or a MSE wall. The program must be prepared by a Professional Engineer
registered in the State of North Carolina and reviewed and approved by the SWS.

ii. The program must be executed with ample time prior to the wall construction.

iii. The collected info and produced results (including conclusions and/or design
modification, as needed) from the program must be submitted to the SWS for a
review and approval and to the consultants contracted to A-1 Sandrock, Inc. for
modify the wall design as necessary.

12. The Engineering Plan shall include the technical specifications pertaining to the design
and performance of the landfill containment and environmental control systems including
the proposed MSE wall components and drainage networks [Rule 15A NCAC 13B
.0539]. Above mentioned tasks are excluded from the FEA’s scope of work for the MSE
wall design (Section 1.3, Appendix 3 of the Engineering Plan); therefore, A-1 Sandrock
must provide detail of surface water and seepage designs.

13. (Section 2.1) Per FHWA specification, the MSE wall backfill shall be compacted to a
specified compaction effort based on the distance from the wall facing. The second
paragraph proposes the “…compacted soil with a target maximum dry density of 90
percent…” shall be revised according to the FHWA specification. Additionally, the
specification of compaction effort in this Section is contradicting those in Sections 2.2
and 4.2.1.1.

14. (Section 2.1.1) The FHWA design and construction guidelines (Publication No. FHWA-
NHI-00-043) is used as one of the reference to design the MSE wall; The guidelines are
based on allowable stress design (ASD) procedures to conduct MSE wall design;
however, the design approaches in Appendix 2 and Appendix 3 of the Application are
based on load and resistance factor design (LRFD) procedures. Please clarify.

15. Please provide a summary of the testing requirements of the MSE walls as described in
the subsection 2.1.1. The referenced testing summary isn’t available in the Section 7 of
the Application.

16. Throughout the entire application document please use the consistent engineering
parameters for all calculations and analyses (settlement, slope stability, bearing capacity,
etc.) in Appendices 2 & 3. There is no reason that same material has different
engineering parameters. If A-1 Sandrock, Inc. insists this approach, the SWS demands
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 8 of 18

A-1 Sandrock, Inc. conduct a sensitive analysis by using lower and upper bound data on
each task conducted in Appendices 2 & 3.

17. (Section 2.1.1) The required minimum factor of safety for minimum reinforcement
length/wall height is 0.8 as described in Section 2.1.1, but the factor of 0.7 is used in
Appendix C1. Please clarify.

18. (Section 2.2) Please address the following concerns:
i. The on-site soil material classified as SM-ML and CL per Unified Soil
Classifications are nor suitable to use as fill material in the reinforcing zone of the
MSW wall according to Section 1.4 in Appendix 3. Please make clarification in
this Section how to use the earthen material in Phases 2B & 3 for selected fill
material for constructing the wall.

ii. Should this section add more info/specification related to the MSE wall
construction? For example, geosynthetic material, weld metal mesh, vegetative
supporting material, etc.

iii. Please provide the procedures/ sequences of the wall construction (referring
Drawing E5 & RW1 through RW-4).

iv. Any off-site borrow is required? How much the selected backfill must be obtained
from off-site borrow. How the borrow material can be confirmed to be suitable for
fill material inside the reinforced zone?

v. Will the 10% organic debris/material in the selected backfill material for the wall
construction meet the specification in Appendix 3? Why is the compaction effort
stated in this section different from that in Section 2.1?

19. (Section 2.4) The wall construction drawings must be part of the Application. The
Drawing E4 shows the wall width is variable and station is different from that in Drawing
E5. Please provide details of wall widths along the station.

20. (Section 2.5.1 Settlement, Page 16) Please provide the source of the referenced waste
density of 0.6 ton per cubic yard. Is the waste density compatible with that in the facility
annual report? Is the loading based on the final, not interim, in-place waste (show the
elevations of the bottom of the waste and of the top of the final cover)?
Appendix 2
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 9 of 18

21. (Appendix 2, Sections 3 & 4.2 & Appendix 2-A) The MSE wall will be seated on the top
of in-placed waste or embankment of the haul road, or haul road as shown on Drawing
E4. The haul road and embankment were not constructed by partial weather rock (PWR)
but compacted on-site soil as described in Section 2.2 of the Engineering Plan.
Throughout the entire application document, A-1 Sandrock must use the consistent
engineering parameters for all calculations and analyses (settlement, slope stability,
bearing capacity, sliding & overturning in Appendix 2 and MSE wall internal and
compound stability analysis in Appendix 3). It is not professional practice of using
different engineering parameters for the same selected materials or foundation strata to fit
in the pre-determined outcome. If A-1 Sandrock, Inc. intends to use this approach, the
SWS demands that A-1 Sandrock, Inc. conducts a sensitivity analysis on each task in
Appendix 2 and Appendix 3 by using all available lower- and upper-bound engineering
parameters – density/unit weight, shear strength, internal friction angles.

22. (Appendix 2, Section 4.2) Please provide the copy of the referenced AASHTO tables.
23. (Appendix 2, Section 5.1 & Facility Plan) According to the Facility Plan, the MSE wall
will be constructed by four (4) stages, but the information provided in Appendix 2-A
shows three (3) wall alignments/stages (?) (with three options of wall heights). Is there
contradicting info described in Facility Plan & Engineering Plan. Please explain.

24. (Appendix 2-B, Global Slope Stability Analyses)
i. Please provide the input data sheet for each round of analysis. The layout
drawing to show the critical slope (cross-sections) locations must be provide in
the Appendix 2-B.

ii. According the historical soil boring logs in Appendix 2-D, there are layers of
sandy silt, silty clay overlain the PWR as described in the Section 2.5.2.1 of the
Engineering Plan.
a. Why those layers inside the landfill waste footprint are eliminated from the
slope stability analysis?
b. Why groundwater table is not considered in the analysis?
c. The deep seated global stability analysis shall be conducted below the MSE
wall; although for the sake of simplicity, the wall unit is a block but the
foundation soil that supporting the wall is not PWR.

25. (Appendix 2-B Settlement Calculations) Please address the following concerns:
i. The soil boring log B-10 is not included in Appendix D.

ii. The consolidation test results are not available in Appendix 2-B.

Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 10 of 18

iii. Provide Hough’s method equations for sand and the selection processes of the
SPT values used in Hough’s method.

iv. Section 2.5.1 & Appendix 2-B of the Engineering Plan concluded that estimated
settlement of the foundation soil underneath the MSE wall of 0.51 feet (5/100) is
acceptable. But the Section 2.1 of Appendix 3 specified the settlement of the soil
underneath the wall shall not exceed 1/100. Please explain the discrepancy and
which one shall be used for the wall project.

26. (Appendix C1, LRFD External Forces Analysis) The external loading arrangement used
in Appendix C1 is different from the loading arrangement as shown on Drawing E5 and
Appendix 3, which shows that:
i. There is no surcharge on the MSE wall except the traffic load (uniform loading)
of 250 pounds per square feet as described in Section 2.0 of the Engineering Plan.

ii. The interim or final soil cover - back slope [3 (horizontal) to 1 (vertical)] of the
C&DLF is located on the backside of the wall, not over the entire wall width of
25 feet.

iii. The retained backfill shall include C&D waste (the solely purpose to build the
wall), not backfill material alone.

iv. The distance of water table, 5 feet, below the bottom of the wall is used, please
provide the reference. Is the data from a nearby monitoring water well? Will the
water level be impacted by the water levels in the Sediment Basin # 1, and nearby
Hickory Creek?

v. Soil parameters for the foundation soil are those for PWR; but the MSE wall will
be seated on the top of in-placed waste or embankment of the haul road, or haul
road as shown on Drawing E4. The haul road and embankment were not
constructed by PWR but compacted on-site soil as described in Section 2.2 of the
Engineering Plan. The input data are irrelevant and inconsistent to the site
conditions.

Based on the findings, the SWS does not think the results from the calculations for each
design wall heights -30, 50, and 60 feet in submitted Appendix C1 and Appendix 3 truly reflects the real field loading conditions that the proposed wall will be encountered. Appendix 3
Mr. Ronnie Petty III ##, 2017 DIN 28647 Page 11 of 18

27. (Appendix 3 MSE Wall Design Report) According to Section 4.2 in Appendix 2, the
retained backfill/C&D waste is a non-cohesive material (e.g. c’ = 0 psf). Additionally,
referring the Comment No. 20 that foundation soil for the wall including sandy/silty soil,
C&D wastes overlying the PWR. Therefore, the entire wall design is based on the
questionable geological and geotechnical information. The modification of the wall
design is possibly warranted.

28. (Section 2.2) Please provide a copy of the material data sheet/specification of the selected
geogrid, FortractTM made by Huesker.

29. (Section 2.4) Please address the following concerns:
i. The seasonal high ground water table for both C&DLF - Phases 1 & 2 areas are
previously confirmed by the 2002 Site Suitability Study Report and the Design
Hydrological Reports as stated in Section 2.5 of the Engineering Plan. The semi-
annual groundwater monitoring reports must be used for the water tale
degermation as well. A-1 Sandrock, Inc. must use the site-specific data to
determine if the groundwater level is greater than 0.66H. If not, the modification
of the wall design is warranted.

ii. The portion of the wall (Stage 1) is very closed to the existing Sediment Basin #1.
The highest water level in the basin must be considered for the wall design.
Especially, when the nearby creek is flooded, and water in the basin may not be
able to drain into the creek for several days which results in infiltration of surface
water/flood water into MSE wall reinforced fill zone (Section 2.4, Appendix 3 of
the Engineering Plan & refer Drawing No. 5, wall is embedded unknown depth
below the existing grade). The wall must design the worst scenario.

iii. (Section 2.4) The wall design should be revised by considering the seepage
generated from landfill leachate that is retained by the wall.

Construction Quality Assurance (CQA) Plan 30. In addition to the landfill construction, the CQA Plan and technical specifications that are
the same documents submitted previously should include construction quality assurance
and control and specifications associated with material and construction of the proposed
MSE wall including reinforcement, graduation & compaction requirements for the
selected fill material, and drainage media, etc.

31. Referring Comment No. 8, if the construction of the MSE wall requires to satisfy local
building codes, the CQA Plan and Technical Specifications must incorporate the code
requirements.
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32. (Section 4.1.2) What is the role and responsibilities of Fitzpatrick Engineering
Associates, PC in the MSE wall project?

33. (Section 4.2.1.3) The listed soil types which are generated from on-site borrows are not
entirely satisfactory use for the selected fill material (excluding fine-grained soils such as
SC, ML, CL, MH, & CH) inside the MSE wall reinforcing zone as described in Appendix
E, Appendix 3 of the Engineering Plan. A-1 Sandrock must produce a CQA Plan for the
material used in the MSE wall construction.

34. (Section 4.1.2.4) The MSE wall has geosynthetic component (geogrid) specified as
reinforcement; therefore, CQA Testing Firm should be both certified soil laboratory and
geosynthetic laboratory. And some tests on geosynthetic material are abiding by the
standardized method by other organization such as GRI. The testing methods and
frequencies are required in the CQA Plan and Technical Specifications. Please make the
necessary revision.
35. (Section 4.2) The CQA Plan, in a minimum, should address the inspection and oversight
of the MSE wall construction (referring Sections 1.2 & 3.0, Appendix 3 of the
Engineering Plan).
i. Who is responsible the inspection & oversight of the MSE wall construction?

ii. The inspection item/checklist & frequency, inspector qualification & authority,
inspection report and submittal

36. (Section 4.3) Please refer the pre-construction requirements stated in Section 3.0,
Appendix 3 of the Engineering Plan.

37. (Section 4.3) This section, in a minimum, should include the requirements for wall
foundation preparation & proof-rolling final grade with specified precision and survey
control, soil classification for fill material, compaction test, wall foundation approval
processes prior to proceeding next task of erecting a layer of wall, and approaches to
handle if a non-conformance foundation soil encounters.
38. Plesae provide the material and construction specification of the material to be used in the
“back drainage” design .
Operations Plan 39. (Section 5.2) The DWM Winston-Salem Regional office contact info has changed, the
correct info is shown below:
450 West Hanes Mill Road, Suite 300, Winston-Salem, NC 27105
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Phone: [phone] Fax: [phone]
40. (Section 5.3) The section may require some revisions to meet the current regulation
change such as a life-of-site permit and past ten years operation experiences.

41. (Section 5.7) Please provide additional info of inspection & monitoring associated with
MSE wall.
i. The constructed MSE wall including both structure components and stormwater
draining system shall be part of routine inspection and maintenance (I&M) tasks,
which shall be conducted by independent third-party according to the requested
I&M Plan for the constructed wall (referring Comment No. 9).

ii. The inspection, monitoring, and maintenance records/reports certified by a
Professional Engineer registered in the State of North Carolina shall be placed in
the operating record in Section 5.12.

42. (Section 5.11) Please describe if the C&DLF is subject to EPA Green House Reporting
requirements and status in the future landfill operation after each stage of wall is
completely constructed.

43. (Section 5.13) The Division Water Quality merged into the Division Water Resource.
Please make necessary correction.

44. (Section 5.14) The Contingency Plan should include the response action plan to handle
the following conditions if failure of the wall segment(s) occurs; in a minimum, the plan
should include, but not limited to the person(s) responsibility for cleanup and site
restoration, verbal and written notifications and timing to submit an incident report and
follow-up action plan to regulatory agencies, and coordination (including firm schedule
of each activity) of restoration of the wall segment(s), removal waste rolled out of waste
footprint, impacted area investigation and remediation, and routine waste disposal
activities if A-I Sandrock is allowed to assume the waste disposal activities.

45. (Sections 6.3 & 7.2) Please provide the correct references in the Application.
i. The reference (in Sections 6.3 and 7.2) for the hazardous waste definition is
incorrect.

ii. The Tables 6.1 and 7.1 are not available in the Application.

46. (Section 6.4.2) Please use the correct acronym of the NC DEQ instead of the NC DENR.
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47. (Table 6A) The wastewater treatment sludge shall be prohibited for treating or processing
at the Processing Facility.

48. (Section 7.3.2) There is no “on-site” waste transfer station in the landfill facility. Please
correct the typo.

49. (Table 7A) The exception for an industrial solid waste as referenced in Rule 15A NCAC
13B .0503(2)(d)(ii)(A) is irrelevant. An industrial solid waste shall not be disposed in a
C&DLF.

Closure and Post-Closure Plans
50. (Section 8.1) The referenced drawings in this subsection are nor consistent to the ones in
the Application. Drawing E-3 is likely show the interim cover of the landfill while Stage
1 wall is constructed.

51. (Section 8.2.2) The permit (DIN 284550) dated October 02, 2017 allows A-1 Sandrock,
Inc. to operate both Phases 1 & 2 of the C&DLF. The Phases1 & 2 encompasses 16-acre
waste boundary and have an approved operating capacity of 1,078,524 cubic yards.
Please update the data in this subsection.

52. (Section 8.3) Please provide additional information to the Post-Closure Plan:
i. The Plan should state how to routinely conduct the maintenance and care of the
vegetation established in the final cover system and facing unit of the wall.

ii. The Plan should detail the monitoring, inspection, repair of the wall during the
post-closure period. The SWS strongly recommend that A-1 Sandrock adopt the
guidance documents published by Federal Highway Administration (FHWA) or
State Department of Transportation (NCDOT) and the White Paper #19 issued by
Geosynthetic Institute (GRI) dated April 19, 2011.

iii. The costs related to each above-mentioned care activities that shall be conducted
by a independent third party must be added to the post closure cost estimate.

53. (Table 8A) Please explain why the unit cost for the following item is less than previously
approved cost estimate for site closure, the credible documents for supporting the cost
reduction must be provide in the Application:
i. VSL; ii. CSB, iii. Establish Vegetation.

54. (Section 8.3) Please address the following concerns:
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i. The Post Closure Plan must address the routine inspection, repair, maintenance
the constructed MSE walls. The emergency response plan for management
wastes and restoration the wall must be appended to the Post Closure Plan.

ii. (Section 8.3.1.3) The drawing MP-1 is likely a typo of Drawing M1/Sheet 11.

iii. The facing unit of the MSE wall is vegetation, please provide a care and
maintenance plan for the vegetative facing unit. The related cost must be added
to the post-closure cost estimate (Table 8C).

iv. (Table 8C) The number of ground water monitoring well is six (6), not five (5).

55. Financial Responsibility [NCGS 130A-295.2] According to Section 2 – Engineering
Plan, the design of MSE wall is based on the FHWA methodology and guidance
documents which state the service life for a long-term permanent retaining wall is
routinely about 75 years. Therefore, in addition to providing a financial assurance
mechanism(s) to cover costs of landfill unit closure, post-closure cares, groundwater
corrective action as needed, and potential assurance and corrective action for the C&DLF
facility, A-1 Sandrock, Inc. must provide:
i. Financial qualification to pay the costs of proper design, construction, operation,
and maintenance of the MSE wall.

ii. Financially responsible for
a. Repairing or replacing the entire walls – Stage 1 through Stage 4 around
the landfill. The costs should include waste removal and replacement
while repairing or replacing the entire walls when the 70-year service life
of the wall expires or the function of the wall is questionable or unsafe to a
human life or adversely damaging environment]), whichever comes first.
The latter is concluded and judged by a profession engineer registered in
the State of North Carolina throughout the routine inspection of the MSE
wall [see Comment No. 9]. The costs for this part should be the same
costs for construction of the wall plus additional costs for removing and
replacing wastes and restore the final cover system.
b. Remediation and cleanup the wastes (including wall materials) and
restoration of the wall in the event of a wall failure. According to GRI
Report No. 40, Dr. Robert Koerner reports “the cost of the remediation
varied from 1.05 times the original cost to 3.50 times. The rebuild case
history was 4.66 times the original cost.” The average costs for this part is
about twice the initial cost of wall construction.
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c. All above-mentioned costs shall be annually adjusted for inflation
according to NCGS 130A-295.2.
Drawings
56. Drawing Sheet 12- MSW Wall Monitoring Locations is not included in the Application.

57. Provide a drawing or drawings of final/interim cover layout which has referenced the
locations of the typical details of erosion and sediment control measures on Drawing EC1
through EC-3.

58. (Drawing E-5, MSE Wall Details) The details of cross-section at Station 26+00 must
include, but not limited to the following items as described in Appendix 2, Section 2.1.1
(on page 12):
i. Drainage systems/networks for surface water, leachate, seepage flow behind the
wall, toe drain (surface water) including various size piping and drainage media.
The hydraulic design of the drainage system must be appended to the Engineering
Plan. The material and construction specifications must be added to the CQA Plan
and the Technical Specification which must meet the requirements stated in
Section 4.0, Appendix 3 of the Engineering Plan.

ii. What is the toe slope of the foundation soil affront of the wall?

iii. The tensile strength of reinforcement is color-coded. For each color zone, please
tabulate the data of the reinforcement strength & length & vertical spacing,
thickness of the layer (by elevations amsl).

iv. The facing of the wall should be constructed with a 6-inch set back/stagger per
course (Section 1.2, Facility Plan). Please show the described setbacks on the
drawing.

v. The back-side of the wall, an earthen material will be backfilled and compacted
between C&D waste and reinforced zone of the wall.
a. Will this non-reinforced zone of the wall be built vertically? Please described
the construction procedures for construction of a 60-feet-tall non-reinforced
earthen wall in the Engineering Plan (same comment applicable to Sheet No.
RW-5 in Appendix 3).
b. Provide the dimensions of the non-reinforced zone of the wall – slopes, base
width, top width, in any (same comment applicable to Sheet No. RW-5 in
Appendix 3).
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c. According to the Facility Plan, the wall will be built vertically by 10 to 12 feet
life/layer per time (1.5-feet per course). In addition to providing the detail of
final cover system of the C&DLF related to the full-height wall, please
provide a typical detail/cross-section of each interim wall height (30 feet and
50 feet) with landfill operating grades.

vi. The details of wall connection details.

vii. What is the embedment depth of the MSE wall (same comment applicable to
Sheet No. RW-5 in Appendix 3)?

viii. The Profile of Stage 1 MSE wall is confusion. What the color code area means?

ix. The profile should be simplified by providing elevations of the existing grade, the
finish grade of foundation layer, the first 10-feet layer, second 10-feet layer, and
so on to the final layer of the Stage 1 wall (approximately 800 feet amsl).

x. A-1 Sandrock may want to verify and confirm if the guardrails installed on the
edge of the top of the wall are required to protect worker driving hauling trucks.
Equipment and/or machinery from fatal accident?

xi. The typical wall section adjacent to the Sediment Basin # 1 (including basin grade
and water level elevation) should be present on this drawing.

59. (Drawing EC-2, Landfill Gas Vent Detail)
i. Should there a layer of geotextile (density of x oz./square yard) to separate the NC
DOT # 57 washed stone from the compacted soil liner at the gas vent trench?

ii. What is the side slope of the gas trench?

iii. Gas pipe material specification is missing. PVC or HDPE, thickness, perforation
size and spacing, etc.

60. The layout, cross-sections, and detail drawings of the comprehensive landfill
development are required; the minimum info should include the landfill base grades
(relative to the rock stratum or seasonal high ground water table), the existing waste fill
grades, component of a MSE wall unit, leachate and stormwater separation devices,
interim grades of different phased landfill development in coordination with wall erection
at four different stages, and final grades of the landfill.

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Please submit a revised Application including a hard copy with a set of full-size drawings and an electronic copy (in pdf format) of the Application. The SWS will conduct the second-round review when the revised Application which incorporates all proper responses to the above-
mention comments. Thank you for your cooperation in this matter. If you have any questions of
the requested application components, please contact myself at 919-707-8251 [e-mail]. Sincerely,

Ming-Tai Chao, P.E. Division of Waste Management, NCDEQ

cc: David Garrett, P.G. P.E., AMEC Foster Wheeler Ed Mussler, Permitting Branch Supervisor Christin Ritter, DWM Susan Heim, DWM Deb Aja, DWM
Central Files