0105_CobleC&DLF_ResponsetoComment_FID1440645_20200804

August 4, 2020
Ming-Tai Chao, P.E.
Permitting Branch, Solid Waste Section
Division of Waste Management
North Carolina Department of Environmental Quality
1646 Mail Service Center
Raleigh, NC 27699-1646

RE: Revisions to the Facility and Closure Plans
Coble’s C&D Landfill
Permit No. 01-05-CDLF-1998
5833 Foster Store Road
Liberty, NC 27298
Project No. 2191087 Phase 02

Dear Ming:

Please find enclosed the revisions to the Facility Plan and Closure Plan submitted on June 24, 2020,
for the Phase 3A Partial Closure of the Coble’s C&D Landfill.

On behalf of Coble’s C&D Landfill, we would like to thank you in advance for reviewing the enclosed
response letter with the revised Facility and Closure Plans, and issuing a Permit to continue to operate
Phase 1, 2, and 3A. Please contact me at [phone] if you have any questions or comments.

Respectfully submitted,
LaBella Associates
Amy Davis, P.E.
Regional Manager, Waste & Recycling Division
Enclosure: Revised Facility Plan
Revised Closure Plan

Copy: Mr. Kent Coble

August 4, 2020
Ming-Tai Chao, P.E.
Environmental Engineer, Solid Waste Section
Division of Waste Management
North Carolina Department of Environmental Quality
Raleigh, NC

RE: 01-05-CDLF-1998 Permit Renewal Application Comments

Dear Ming:
LaBella has prepared responses to your comments received on July 28, 2020 on behalf of
Coble C&DLF. Responses are prepared for the comments 1 and 2 related to the revisions to
Facility Plan and Closure Plan. Responses to the comment 3 we have referred to Coble’s to
prepare the information you have requested. Section comments are repeated as they
appeared on the July 28, 2020 email, and our responses to the comments are in bold font
for clarity and ease of reading.

After reviewing the revised Facility Plan and Closure/Post-Closure Plan (FID 1427892), the
Solid Waste Section has few comments on the plans below:

1. Facility Plan – Section 2, Landfill Capacity
i. The approved gross capacity of the CDLF is of 6,935,903 cubic yards (CY). Per
Rule 15A NCAC 13B.0537(e)(2), gross capacity is defined as the volume of the
landfill calculated from the elevation of the initial waste placement through the
top of the final cover, including any periodic cover. Please revise the statement of
gross capacity by including the volume of the proposed 3-feet-thick final cover
system and revise the statements of the remaining waste volume and landfill
service life accordingly.

Section 2 has been revised.

2. Closure Cost Estimate
As stated in Section 2, the approved waste footprint of Phases 1, 2 & 3A is 18.3 acre in size, and the certified closed area is 14.6 acres in size (=4.2+0.9+3.9+5.6).
i. Please provide the consistent certified closed area (14.6 vs. 14.73 acres in size).

2

Phases 1, 2 and 3A waste footprints equal 18.3 acres.
Partially closed acreages total 14.6 acres.
Remaining open areas total 3.7 acres.

ii. The remaining active disposal area is 3.7 acres in size, not 3.6 acres.
Remaining open areas total 3.7 acres.

iii. Revise the closure cost estimates by using the correct quantity of 3.7 acres to
finalize the cost estimates for a closure.

Closure cost estimate has been revised according to 3.7 acre area.

iv. Add a note to the cost item of the earthen material to indicate the borrow
source(s).

Note to indicate borrow source has been added.

v. The cost estimate to close the sanitary landfill shall base on the cost of hiring a
third party to execute the approved tasks in accordance with the facility's closure
plan [Rule 15A NCAC 13B. 1802(a)(2)]. The unit cost for each cost item in the
closure cost estimate dated July 2020 is far less than that dated December 2019,
the side-by-side comparison of each unit cost is summarized below. Please
explain why the unit cost is reduced.

Cost item - Closure Unit Price
(12/2019)
Unit Price
(07/2020)
Difference
Mobilization 5,270 5,000 -270
18” Clay (10E-5 cm/sec) 6 3.5 -2.5
18” Field & Lab testing 2,418 2,294 -124
18” Vegetative Soil 4 3.5 -0.5
Seeding/Revegetation 1,581 1,500 -81
Gas Vent Installation 5,500 0 -5,500
E&S/Stormwater BMPs 85,000 0 -85,000
Survey 1,581 1,500 -81
Coble Sandrock C&D Landfill Permit 0105 CDFL 1998
C&D Waste Gross February 8, 2016 DIN 25405
Landfill
Phase
Footprint
(Acres)
Capacity
CY Permit Status
1 6.5(1)365,301 4.2 ac closed / 2.3 ac in active
2A 0.9(1)0.9 ac closed (1)
2B 4.6(1)3.9 ac closed / 0.7 ac incative
3A 6.3 570,662 5.6 ac closed /0.7 ac in active
320,000

3

An older version of the closure cost estimate has been replaced using the
costs provided in the December 2019 table.

3. Coble’s Sandrock, Inc. shall provide additional financial assurance (FA) / closure cost
estimate for each of the waste storage, treatment, and process units. Except those non-
disposal units listed in Rule 15A NCAC 13B. 1801(a) effective July 1, 2020, the
following non-disposal solid waste management units listed in the Operations Plan dated
August 2019, shall provide FA/closure cost estimate according to Rule 15A NCAC 13B.
1802(a)(1):
• Wood wastes including recovered from C&D waste stream – clean unpainted
lumber, plywood/engineering wood, pallets, woody components from destructed
mobile homes etc. (yard waste and land clearing and inert debris are excluded)

Wood waste is not stockpiled at the facility.

• Scrap tires.

Scrap tires are not stockpiled at the facility.

• Scrap metals including white goods, metal components from destructed mobile
homes.

Frequently sold metal crap is not stockpiled at the facility.

• Cardboard boxes.

Cardboard is not stockpiled at the facility.

• Post-consumer asphalt shingles,

Post-consumer asphalt shingles are not currently stockpiled at the facility.

• Any other recovered wastes stored on-site.
i. Pursuant to Rule 15A NCAC 13B .1802(a)(1), Coble’s Sandrock, Inc. shall
provide the FA and supporting calculations of the costs for closing each unit that
listed in the Operations Plan. The closure cost estimate shall be calculated by
multiplying
a. The maximum tonnage of waste (noted with dimensions of each stockpile)
permitted to be stored at the on-site location (noted with extent of storage unit
in square feet, square yards or acres) at any given day by
b. The cost per ton for a third party to remove the waste, transport it, and dispose
of it at the nearest facility permitted to receive such waste.

4
Coble reports that no stockpiles of lumber, plywood/engineering wood,
pallets, woody components from destructed mobile homes, or any other
materials listed above. Closure Plan Section 5 Cost Estimate for Closure
has not been revised to include stockpiled materials.

ii. Coble’s Sandrock, Inc. shall annually adjust the closure cost estimate and the
amount of financial assurance for inflation, establish and maintain financial
assurance for closure of the facility and according to Rules 15A NCAC 13B
.1802(b), (c) & (d).

Closure cost estimate and the amount of financial assurance for inflation will
be prepared annually.

Respectfully submitted,

LaBella Associates

Hannu Kemppinen
Sr. Project Consultant

Prepared For:
COBLE’S SANDROCK, INC.
5833 FOSTER STORE ROAD
LIBERTY, NORTH CAROLINA 27298

Submitted By:
LaBella Associates
2211 West Meadowview Rd.
Suite 101
Greensboro, NC 27407
336-323-0092
NC License No. C-0430

FACILITY PLAN
COBLE’S SANDROCK
CONSTRUCTION & DEMOLITION DEBRIS LANDFILL
PERMIT NO. 01-05
august 2019, revised August 2020
Project no. 2191087
II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
1
TABLE OF CONTENTS

FACILITY PLAN .................................................................................................................................1
1. Waste Stream ......................................................................................................................2
2. Landfill Capacity ..................................................................................................................3
3. Special Engineering Features ............................................................................................6
4. Partial Closure of the Landfill .............................................................................................7

FIGURES Site Location Map Partial Closure Survey Maps TABLES Table 1 Future Tonnage Projection DRAWINGS

Drawing FP-01 Facility Plan – Site Development
Drawing FP-02 Facility Plan – Proposed Final Contours
Drawing FP-03 Facility Plan – Facility Boundary Plat

APPENDICES
Appendix 1 Franchise Agreement
Appendix 2 Slope Stability

FACILITY PLAN

This facility plan defines the development of the Coble’s Sandrock C&D landfill property and
describes the permit of an existing facility. This plan includes drawings, which present the
long-term, general design concepts related to construction, operation, and closure of the
C&DLF unit(s). Additional solid waste management activities located at the C&DLF facility
are identified in the plan to meet the requirements of the SWMP .0537 Subchapter. The
facility plan defines the waste stream proposed for management at the C&DLF facility,
different types of landfill units or non-disposal activities included in the facility design, and
describe general waste acceptance procedures.

The facility will accept construction and demolition (C&D) debris, and other wastes similar to
those typically found in the accepted waste streams such as roofing shingle waste from the
manufacturer, waste building materials from mobile home manufacturers and wooden
pallets for disposal. No municipal solid waste, hazardous waste, industrial waste, liquid
waste, or waste not characterized as LCID or C&D, shall be accepted for disposal.

II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
2

The areal limits of the C&DLF unit(s), total capacity of the C&DLF unit(s), and the proposed
waste stream must be consistent with the Division's approval set forth in accordance with
Rule .0536 (a)(1). Revised Facility and Engineering Plans Drawings (FP-01, FP-02 and EP-
04, EP-05) provide the information required in Section .0537(d).

1. Waste Stream

Types of Waste Specified for Disposal: Only construction/demolition debris will be accepted
at the C&D landfill. Construction and demolition debris defined in NC General Statutes is
waste or debris resulting solely from construction, remodeling, repair, or the demolition of
pavement, buildings, or other structures.

Service Area: The Alamance County Franchise Agreement, provided in Appendix 1, limits the
service area to be served by the Coble’s Sandrock Landfill to customers within 25 miles
from the site. Existing customers outside the 25-mile service limitation are grandfathered
under the Franchise Agreement and Coble's Sandrock may continue to accept wastes from
these customers. Coble's Sandrock may also accept waste from new customers outside the
25-mile service area to replace existing customers outside the service area; however, first
priority in terms of disposal capacity is to be given to waste generated within Alamance
County.

The Counties from which the facility has previously taken waste include Alamance, Cabarrus,
Caswell, Chatham, Davidson, Forsyth, Green, Guilford, Lee, Orange, Randolph, Rockingham,
and Wake. Alamance County recognizes that the Coble Sandrock C&D landfill currently
accepts waste from customers outside the 25-mile radius, and these existing customers are
grandfathered under the Franchise Agreement. New customers outside the 25-mile radius
may be accepted to replace the existing customers in accordance with Section 4 of the
Franchise Agreement.

Segregation Management Procedures: Recyclable material are allowed to be segregated
from the waste stream and temporarily stored in containers or stockpiles prior to removal
from the site. Recyclable material may include wood, metals, concrete, plastic, cardboard,
and other materials with appropriate recycling markets. Scrap metal is removed from the
site frequently and taken to a metal recycling facility. Coble’s Sandrock deconstructs mobile
trailer homes at the working face of the C&D landfill. Identified C&D waste material
removed from the deconstruction process is placed into the landfill. The franchise
agreement requires monitoring waste and to reject any significant levels of asbestos.

The locations of the mobile trailer home deconstruction area and the recyclables storage
areas follow the location of the working face as it progresses across the landfill.

II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
3
Equipment: Coble Sandrock proposes to operate the following equipment at the C&D
landfill:
CAT 330 CL
CAT 973 Loader
CAT D8 Dozer
CAT Rubber Tire Loader
TREX off-road Truck
TREX Pan
TREMAC Shear Muncher
Precision Husky Tub Grinder
Power Screen Screener
Fuel Truck
Link Belt Trackhoe

Equipment may be added or deleted, depending condition to upgrade and on the volume of
waste accepted.

2. Landfill Capacity

Overall Facility Life
Gross airspace for waste, operational cover soil, intermediate cover material and final cover
for the entire facility is 6,935,903 cy. Approximately 324,279 cy of soil will be needed for
final cap (3 feet thick) construction. Assuming that 10% of the remaining volume will be
operational cover soil (661,162cy), 5,918,033 cy are available for waste material. Utilizing
in-place waste density of 1050 lbs/cy, the tonnage capacity of the landfill would be
approximately 3,106,968 tons. The in-place waste density stated above is within the typical
range of densities measured for C&D debris.

Based on excerpt from the historical record (Table 1), Coble’s C&D landfilled an average of
14,004.85 tons/year during the previous five-year period 2016-2020; cumulative in-place
waste volume as of July 2020 is 719,433 tons or 1,131,537 cy. Using the recent five-year
landfilled average, the remaining capacity calculates approximately 124,426 cy until 2023
in the permitted Phases 1-3A (1,255,963 cy). Subsequently, when permitted to operate,
Phase 3B added capacity 349,213 cy, the full date for Phases 1-3B is estimated until 2037
(1,605,176 cy).
Permitted capacities are shown in the below:

II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
4
Phase Acres Acres
(Revised)
Gross
Capacity (CY)
1 7.0 6.5 365,301
2 5.8 5.5 320,000
3A 6.3 6.3 570,662
3B 5.8 349,213
4 8.2 1,043,245
5 7.0 890,575
6 8.0 1,017,800
7 6.9 877,852
8 11.8 1,501,255
Totals 66.8 18.3 6,935,903
Permitted Capacity for each Phase
Permit Status
Approved for
development,
requires submittal
of PTC/PTO
PTO (9/30/1998)
PTO (5/20/2003)
PTO (4/29/2011)
PTC (1/30/2009)

Note in the permit that modified the waste footprints of Phase 1, 2A and 2B. The perimeter
road is constructed in the approved waste footprint of Phases 1 (0.5 acres), 2A (0.1 acres),
and 2B (0.2 acres). Since no waste has ever been disposed underneath the perimeter road,
the areas occupied by the road (approximately 0.8 acres in total) are excluded from the
originally approved waste footprint of 66.8 acres (DIN 24357). The gross capacities were
not reduced from the originally permitted volumes.

On the next page Table 1. Future Tonnage Projections are based on recent five-year average
tonnage landfilled.

II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
5

COBLE SANDROCK C&D LF
Annual
Report
Tons
Received
Waste in Place
(tons)
Air Space
Consumed
Annual (CY)
Air Space
Consumed
Cumulative
(CY)
Survey
Date
UF
(tn/cy)
Density
(lbs/cy)
Remaining
Capacity
each Phase
(CY)
Remaining
Capcity
Entire
Facility (CY)
Facility
Cumulative
(CY)
TABLE 1 - FUTURE TONNAGE PROJECTION

2014 11,046.38 639,454.44 16,558 958,539 6/13/2014 0.67 1334 297,424 5,977,364
2015 9,954.39 649,408.83 15,201 991,714 7/15/2015 0.65 1310 264,249 5,944,189
2016 14,891.36 664,300.19 30,281 1,021,995 6/28/2016 0.49 984 233,968 5,913,908
2017 13,539.15 677,839.34 30,316 1,052,311 7/25/2017 0.45 893 203,652 5,883,592
2018 12,411.09 690,250.43 23,640 1,075,951 6/21/2018 0.53 1050 180,012 5,859,952
2019 16,262.60 706,513.03 30,976 1,106,928 0.53 1050 149,035 5,828,975
2020 12,920.07 719,433.10 24,610 1,131,537 0.53 1050 124,426 5,804,366
2021 14,004.85 733,437.95 26,676 1,158,213 0.53 1050 97,750 5,777,690
2022 14,004.85 747,442.81 26,676 1,184,889 0.53 1050 71,074 5,751,014
2023 14,004.85 761,447.66 26,676 1,211,565 0.53 1050 44,398 5,724,338 Phase 3A
2024 14,004.85 775,452.52 26,676 1,238,241 0.53 1050 366,935 5,697,662 Phase 3B
2025 14,004.85 789,457.37 26,676 1,264,917 0.53 1050 340,259 5,670,986
2026 14,004.85 803,462.22 26,676 1,291,593 0.53 1050 313,583 5,644,310
2027 14,004.85 817,467.08 26,676 1,318,269 0.53 1050 286,907 5,617,634
2028 14,004.85 831,471.93 26,676 1,344,945 0.53 1050 260,231 5,590,958
2029 14,004.85 845,476.79 26,676 1,371,620 0.53 1050 233,556 5,564,283
2030 14,004.85 859,481.64 26,676 1,398,296 0.53 1050 206,880 5,537,607
2031 14,004.85 873,486.49 26,676 1,424,972 0.53 1050 180,204 5,510,931
2032 14,004.85 887,491.35 26,676 1,451,648 0.53 1050 153,528 5,484,255
2033 14,004.85 901,496.20 26,676 1,478,324 0.53 1050 126,852 5,457,579
2034 14,004.85 915,501.06 26,676 1,505,000 0.53 1050 100,176 5,430,903
2035 14,004.85 929,505.91 26,676 1,531,676 0.53 1050 73,500 5,404,227
2036 14,004.85 943,510.76 26,676 1,558,352 0.53 1050 46,824 5,377,551
2037 14,004.85 957,515.62 26,676 1,585,028 0.53 1050 20,148 5,350,875 Phase 3B
Note:Table is based on annual average tonnage of 14,004.85 landfilled from 2016 thru 2020.
Cumulative volume includes weekly cover soil.
Utilization factor 0.53 is representative for the industry .

Future phases 4-8 approved for development require permits to construct and operate.

Overall Facility Soil Balance
The base grading plan, including access roads, for the entire facility yields a net 1,537,784
cy of cut. Approximately 324,279 cy of soil will be needed for final cap (3 feet thick)
construction. Assuming 10% of the permitted landfill volume 693,590 cy of soil will be
needed for weekly cover soil material. Subtracting the estimated soil requirements from the
calculated available material leaves an excess of 519,914 cy of soil.

Phase 3B
To evaluate the air space requirement for a 5-year phase, assuming an average annual
tonnage of 14,004.85 tons/year, the projected total tonnage for the next 5-year phase is
70,024 tons. Assuming an average (UF 0.53 tn/cy) annual consumed air space of 37,112
cy/year, the projected cumulative volume for next 5-year phase would be 185,564 cy.
Closure cap soil volume for 3B is estimated 28,072 cy. Phase 3B permitted gross capacity is
II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
6
349,213 cu. Assuming the waste disposal at the recent five-year average rate, the capacity
would be reached some time during 2037 as shown in the Table 1.

Phase 3B has been under construction and the grading was completed in June 2019. In
order to keep active working face under 4 acres in accordance with the Permit to Operate,
Coble postpones the Phase 3B application of 5.8 acre footprint until later date. At that time
the 3B Construction report will be submitted to the Section for review and issuance for
Permit to Operate.

3. Special Engineering Features

Containment and Environmental Control Systems

Cap System:

The cap system is described from bottom to top in the following paragraphs.

Infiltration Barrier: The infiltration barrier is proposed to consist of either (1) 18 inches of
compacted soil with a permeability no greater than 1x10-5 cm/sec; or (2) a geosynthetic clay
liner. The low-permeability soil barrier, or the GCL, will lie directly above an intermediate soil
cover layer of at least 12 inches in thickness. GCL stability analysis and specifications are
included in Appendix 2 of this Plan.

Erosion Control Components (Protective Layer and Erosion Layer): A protective layer
consisting of at least 12 inches of local soil will be placed on top of the infiltration barrier.
The erosion and protective layers will not be heavily compacted to promote vegetative
growth.

Vegetative Cover: After placement of the protective layer, the area that has been closed will
be seeded with a grass mixture. Mulch and erosion control matting will be used as needed
to further minimize erosion and promote vegetative growth.

Leachate Management Systems:

Leachate collection and management systems are not designed or permitted for this
construction and demolition unlined waste disposal facility.

Base Liner Systems:

The base of the landfill is excavated to designed base grades and remaining native soil will
serve as the base of the landfill, with the condition that the upper two feet of the base soils
consist of the following soil types: SC, SM, ML, CL, MH, or CH (according to Unified Soil
Classification System).

II - Facility Plan Labella Associates, PC.
C&D LF 5-Year Permit Renewal/LOS August, 2019
Coble Sandrock, North Carolina Revised August 2020
7
Gas Management System:

Passive gas vents will be installed to a minimum depth of 10-feet below surface in the waste
mass at a frequency of one vent per acre.

4. Partial Closure of the Landfill

The west side of the landfill Phases 1 and 2 Coble closed in 2012-2013 and the CQA report
was submitted to the Section in August 2013. Coble continued the partial closure of Phase
3A in the areas 14 thru 17 since 2014 and completed the work in 2020. At completion of
the closure efforts, the partial closure CQA report includes the areas 12-17. Partial closure
surveys are included in the Figures attachment of this Plan. The financial assurance for the
C&D landfill will be revised in accordance with rule .01628.

END
COBLE SANDROCK C&D LF
Annual 
Report Tons Received Waste in Place 
(tons)
Air Space 
Consumed 
Annual (CY)  
Air Space 
Consumed 
Cumulative 
(CY)
Survey Date UF 
(tn/cy)
Density 
(lbs/cy)
Remaining 
Capacity each 
Phase (CY)
Remaining 
Capcity Entire 
Facility (CY)
Facility 
Cumulative 
(CY)
1998
1999 14,111.32       14,111.32         
2000 40,488.38       54,599.70         
2001 99,225.55       153,825.25       
2002 79,035.85       232,861.10       
2003 78,328.36       311,189.46       
2004 57,962.06       369,151.52       
2005 57,855.27       427,006.79       
2006 55,849.02       482,855.81       
2007 49,981.45       532,837.26       
2008 40,428.22       573,265.48        51,905 736,000 5/30/2008 0.78 1558 6,199,903       
2009 14,488.29       587,753.77        844,632 6,091,271       
2010 12,769.32       600,523.09        18,156 853,861 6/8/2010 0.70 1407 6,082,042       
2011 10,104.71       610,627.80       
2012 8,428.04         619,055.84       
2013 9,352.22         628,408.06       
2014 11,046.38       639,454.44        16,558 958,539 6/13/2014 0.67 1334 297,424           5,977,364       
2015 9,954.39         649,408.83        15,201 991,714 7/15/2015 0.65 1310 264,249           5,944,189       
2016 14,891.36       664,300.19        30,281 1,021,995 6/28/2016 0.49 984 233,968           5,913,908       
2017 13,539.15       677,839.34        30,316 1,052,311 7/25/2017 0.45 893 203,652           5,883,592       
2018 12,411.09       690,250.43        23,640 1,075,951 6/21/2018 0.53 1050 180,012           5,859,952       
2019 16,262.60       706,513.03        30,976 1,106,928 0.53 1050 149,035           5,828,975       
2020 12,920.07       719,433.10        24,610 1,131,537 0.53 1050 124,426           5,804,366       
2021 14,004.85       733,437.95        26,676 1,158,213 0.53 1050 97,750             5,777,690       
2022 14,004.85       747,442.81        26,676 1,184,889 0.53 1050 71,074             5,751,014       
2023 14,004.85       761,447.66        26,676 1,211,565 0.53 1050 44,398             5,724,338        Phase 3A
2024 14,004.85       775,452.52        26,676 1,238,241 0.53 1050 366,935           5,697,662        Phase 3B
2025 14,004.85       789,457.37        26,676 1,264,917 0.53 1050 340,259           5,670,986       
2026 14,004.85       803,462.22        26,676 1,291,593 0.53 1050 313,583           5,644,310       
2027 14,004.85       817,467.08        26,676 1,318,269 0.53 1050 286,907           5,617,634       
2028 14,004.85       831,471.93        26,676 1,344,945 0.53 1050 260,231           5,590,958       
2029 14,004.85       845,476.79        26,676 1,371,620 0.53 1050 233,556           5,564,283       
2030 14,004.85       859,481.64        26,676 1,398,296 0.53 1050 206,880           5,537,607       
2031 14,004.85       873,486.49        26,676 1,424,972 0.53 1050 180,204           5,510,931       
2032 14,004.85       887,491.35        26,676 1,451,648 0.53 1050 153,528           5,484,255       
2033 14,004.85       901,496.20        26,676 1,478,324 0.53 1050 126,852           5,457,579       
2034 14,004.85       915,501.06        26,676 1,505,000 0.53 1050 100,176           5,430,903       
2035 14,004.85       929,505.91        26,676 1,531,676 0.53 1050 73,500             5,404,227       
2036 14,004.85       943,510.76        26,676 1,558,352 0.53 1050 46,824             5,377,551       
2037 14,004.85       957,515.62        26,676 1,585,028 0.53 1050 20,148             5,350,875       Phase 3B
Note: Table is based on annual average tonnage of 14,004.85 landfilled from 2016 thru 2020.
Cumulative volume includes weekly cover soil.
Utilization factor 0.53 is representative for the industry .
TABLE 1 ‐ FUTURE TONNAGE PROJECTION
Prepared For:
COBLE’S SANDROCK, INC.
5833 FOSTER STORE ROAD
LIBERTY, NORTH CAROLINA 27298

Submitted By:
LaBella Associates
2211 West Meadowview Rd.
Suite 101
Greensboro, NC 27407
336-323-0092
NC License No. C-0430

CLOSURE & POST-CLOSURE CARE PLAN
COBLE’S SANDROCK
CONSTRUCTION & DEMOLITION DEBRIS LANDFILL
PERMIT NO. 01-05
august 2019, Revised august 2020
Project no. 2191087
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 1 August 2019
Coble’s Sandrock, North Carolina Revised August 2020

Contents

CLOSURE & POST-CLOSURE CARE PLAN .................................................................................................................... 2
CLOSURE ....................................................................................................................................................................... 2
1. Description of Cap System: ............................................................................................................................. 2
2. Closure Area ..................................................................................................................................................... 2
3. Waste Inventory ............................................................................................................................................... 3
4. Schedule .......................................................................................................................................................... 3
5. Cost Estimate for Closure................................................................................................................................ 4
6. Closure Certification ........................................................................................................................................ 4
7. Deed Recordation ............................................................................................................................................ 5
POST CLOSURE ......................................................................................................................................................... 5
1. Contact ............................................................................................................................................................. 5
2. Security ............................................................................................................................................................ 5
3. Post-Closure Maintenance .............................................................................................................................. 6
4. Inspection Plan ................................................................................................................................................ 6
5. Post-Closure Land Use .................................................................................................................................... 7
6. Post-Closure Cost Estimate .............................................................................................................................. 7

APPENDICES
APPENDIX A GROUNDWATER MONITORING WELL MAINTENANCE RECORD
APPENDIX B POST-CLOSURE INSPECTION RECORD
APPENDIX C METHANE MONITORNG TEST RECORD
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 2 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
CLOSURE & POST-CLOSURE CARE PLAN

CLOSURE

1. Description of Cap System:
The cap system to be used is designed to minimize infiltration and erosion. The cap system
will consist of:
• A low-permeability infiltration layer of at least 18 inches with a permeability not
greater than 1.0 x 10-5 cm/sec; or geosynthetic clay liner (GCL);
• An erosion layer that contains a minimum of 12 inches of earthen material that is
capable of sustaining native plant growth. Approved Alternate Cover Material (ACM)
mulch/soil mixture in accordance Operations Plan Section 4 Cover Materials
Requirements.

Construction of the cap system was prepared in accordance with Rule .0540 of this Section
and the following requirements:
(A) post-settlement surface slopes will be a minimum of five percent and a
maximum of 33 percent; and
(B) a gas venting or collection system will be installed below the low-
permeability barrier to minimize pressures exerted on the barrier.

The construction of the closure cap will be in accordance with the Volume 2 Application for
Permit to Construct Phase 3 and the specifications provided in Appendix IV. The Application
to Construct Phase 3 was approved by the SWS on 2/19/2009.

Procedures for Cap Installation
The construction of the cap will be in accordance with the specifications provided in
Appendix IV.

2. Closure Area

Portions of Phases 1, 2A/B and 3A are active for landfill operations. Summary table below
shows current status of the landfill phases open and closed acreages. Active landfill closure
applies to the top area of Phases 1 and 2A/B piggyback and 3A.

C&D LF Closure vs. Open Area Summary

Phase Permitted Revised
Footprint
Closed Open
1 7 6.5(1) 4.2 2.3
2A 1 0.9(1) 0.9 0
2B 4.8 4.6(1) 3.9 0.7
3A 6.3 6.3 5.6 0.7
1-3A 19.13 18.3 14.6 3.7

V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 3 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
Note in the permit modified the waste footprints of Phase 1, 2A and 2B. The perimeter road
is constructed in the approved waste footprint of Phases 1 (0.5 acres), 2A (0.1 acres), and
2B (0.2 acres). Since no waste has ever been disposed underneath the perimeter road, the
areas occupied by the road (approximately 0.8 acres in total) are excluded from the
originally approved waste footprint of 66.8 acres (DIN 24357).

3. Waste Inventory

As of July 2020 annual facility reporting, the cumulative tonnage received and landfilled was
719,433 tons since the beginning of operations (1999). At an average density of 1050
pounds/cubic yard, this equates to approximately 1,131,537 cubic yards of consumed
airspace.

4. Schedule

The Phases 1, 2 and 3A permitted capacity is 1,255,963 cy. Subtracting current
approximately consumed 1,131,537 cy of airspace, the balance is estimated 124,426 cubic
yards. The three-foot thick closure cap is expected to consume 4,840 cy/acre. Following
landfill Phase 1 and 2 closure of 9.13 acres and Phase 3A closure of 5.6 acres, the
remaining active area shown in the above table is approximately 3.7 acres. The remaining
area to be closed is expected to take 17,910 cy reducing landfilling airspace (124,426 –
17,910) to 106,516 cubic yards. Based on the recent five-year landfilled average of 26,676
cu/year the remaining airspace is estimated under 4 years or some time in 2023.

Prior to beginning final closure, Coble’s Sandrock must notify the Division that a Notice of
Intent to close the facility has been placed in the operating record.

Phase 3B is pending completion and permit to operate (PTO). Phases 4 through 8 approved
for future development require submittals of PTC/PTO applications.

The permitted C&DLF gross capacity of Phases 1-8 is 6,935,903 cy. As of July 2020 the
estimated consumed air space is 1,131,537 cy. The remaining gross balance leaves
5,804,366 cy for waste, weekly cover, and final cap.

Closure activities are proposed to begin within 30 days of final receipt of waste.
Construction of the closure cap is to be completed within 180 days following the initiation of
closure activities. The total length of the proposed closure period is 210 days following the
final receipt of waste.

Proposed Closure Milestones and Schedule
Milestone Proposed Schedule from the Date of
Final Receipt of Waste Testing of borrow sources Within 6 months prior to closure Grading of intermediate cover Within 30 to 60 days Placement of soil cap 30 to 150 days
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 4 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
Milestone Proposed Schedule from the Date of
Final Receipt of Waste Final inspection of cap by P.E. 150 to 180 days Construction of stormwater
controls
90 to 180 days
Seeding and mulching 150 to 180 days Preparation of survey plat 180 to 210 days Submittal of closure certification 180 to 210 days

5. Cost Estimate for Closure
Closure Cost Estimate for 3.7 Acres

6. Closure Certification

A professional engineer, registered in the State of North Carolina, will verify that the closure
has been completed in accordance with the Closure Plan. The contents of the signed
Certification Report will be as described below.

Permit renewal 2020
Open Area August 2020 3.7 acres
Areas 1, 2A/B and 3A 2020 FA
COMPONENT Qty UNITS UNIT COST ($)TOTAL ($)
Mobilization EA 5,270$ 5,270$
18" Clay (10E-5 cm/sec)8,954 CY 6$ 53,724$
18" Field & Lab testing AC 2,418$ 8,947$
18" Vegetative Soil 8,954 CY 4$ 35,816$
Seeding/Revegetation AC 1,581$ 5,850$
Gas Vent Installation 1/ac 10 EA 5,500$ 55,000$
E&S/Stormwater BMPs EA 85,000$ 85,000$
Survey EA 1,581$ 5,850$
Stockpiled Materials NA NA NA -$
Subtotal:255,456$
Engineering/CQA (~5%)12,773$
Contingency (~5%)12,773$
TOTAL 281,001$
Closure soil material assumed from on-site borrow.
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 5 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
Certification Reports:

The CQA report will contain the results of the construction quality assurance and
construction quality control testing results, descriptions of procedures, and results of
retesting. The CQA report will contain as-built drawings noting any deviation from the
approved engineering plans and will also contain a narrative including, but not limited to,
CQA daily reports with photographs of major project features, and documentation of
proceedings of all progress and troubleshooting meetings. The CQA report will be submitted
after completion of construction of the cap system in accordance with the requirements of
Rule .0543. The CQA report must bear the seal of the project engineer and a certification
that construction was completed in accordance with the CQA Plan and acceptable
engineering practices.

7. Deed Recordation

Following closure, the owner or operator will record a notation on the deed to the landfill
facility property at the local county Register of Deeds office, or some other instrument that is
normally examined during title search, and notify the Division that the notation has been
recorded and a copy has been placed in the operating record. The notation on the deed
shall in perpetuity notify any potential purchaser of the property that the land has been used
as a C&D landfill unit or facility and its use is restricted under the closure plan approved by
the Division.

POST CLOSURE

Post-closure activities must be conducted at the landfill for a period of 30 years following
closure of the landfill. However, the length of the period can be increased or decreased in
accordance with Division directives.

1. Contact

Coble’s Sandrock, Inc. will handle questions and/or problems, which might occur during the
post-closure care period.

CONTACT PERSON: Mr. Kent Coble
OWNER: Mr. Kent Coble
ADDRESS: 5833 Foster Store Road
Liberty, North Carolina 27298
PHONE NUMBER: [phone]
FAX: [phone]
2. Security

Control access to the site by the use of barriers and gates at roadway entrances. Maintain
these control devices throughout the post-closure care period, and inspected as part of the
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 6 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
monthly inspection program. Mark all barriers and gates clearly with signs stating the name
and nature of the facility and the person to contact in case of emergency or breach of
security.

3. Post-Closure Maintenance

Post-closure maintenance and monitoring will be conducted at the landfill for a period of 30
years after final closure. The Division may decrease the length of the post-closure period if
the owner or operator demonstrates that the reduced period is sufficient to protect human
health and the environment, and the Division approves this demonstration. The period
might be increased by the Division if the Division determines that the lengthened period is
necessary to protect human health and the environment.

Monitoring will include semi-annual sampling of groundwater and surface water, quarterly
gas monitoring, and quarterly inspection of the final cover and monitoring and control
systems. Maintenance needs identified through the monitoring program must be initiated
no later than 60 days after the discovery, and within 24 hours if a danger or eminent threat
to human health or the environment is indicated. Minor cap maintenance may be deferred
until there is a sufficient amount of work to justify the mobilization of equipment and
personnel.

Add soil to the cap as necessary to correct the effects of settlement and subsidence of the
landfill and to prevent run-on and run-off from eroding the final cap.

Protect and maintain stormwater control devices, surveyed benchmarks, groundwater
monitoring wells, surface water monitoring/sampling gauges and LFG wells.

If seeps are discovered, an investigation of why there is a seep and if the cap integrity has
been compromised shall be performed. If the clay cap has released leachate the cap will be
repaired and recompacted to closure CQA required levels and the vegetative layer will be
reestablished.

Mow vegetation twice per year. Cost for routine maintenance assumes 10% of the cap area
will require reseeding and fertilizing each year.

Maintain and repair security fencing, gates, and access roads as necessary.

4. Inspection Plan

Routine inspections will be conducted throughout the post-closure care period. These
inspections will be carried out quarterly unless problems are detected that indicate that
more frequent visits are warranted. Potential impacts to the public and environment will be
considered in determining the inspection frequency. Items to be included in the monthly
inspection will be as follows:

• Access and security control,
• Stormwater management,
• Erosion and sediment control,
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 7 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
• Edge markers of the landfill waste footprint/disposal boundary,
• Gas management,
• Groundwater and landfill gas monitoring systems, and
• Vector control.

The quarterly inspections will be carried out by someone properly trained and
knowledgeable about landfills, such as the landfill owner, operator or engineering
consultant. The results of the inspections will be documented in Post Closure Inspection
Form. If inspections indicate that repairs are necessary, repairs will be initiated as soon as
practicable.

If a leachate seep or outbreak is observed in the routine inspection tasks as noted in
Appendix B, a verbal notice to the SWS within 24 hours and within 15 days a written
notification with the assessment sampling plan must be submitted to the SWS. The
leachate releases assessment/sampling guidance that can be found in the following web
link should be appended to the plan:
https://edocs.deq.nc/gov/WasteManagement/0/edoc/1319075/MSW%20Leachate_Relea
ses_Sampling_Guide.pdf?searchid=22b91c58-be48-4f48-97ecae3766e88565

In addition to the routine quarterly inspections, special inspections will be performed and
documented after events, which may cause damage to the integrity of the landfill cover,
such as heavy rainfall. Inspection may also be necessary following written or verbal
complaints, vandalism or fires. Following special inspections, any necessary repairs will be
initiated as soon as practicable.

Maintain records of all inspections in the operating record.

5. Post-Closure Land Use

The primary land use for the site after closure of the landfill will be open dormant green
space. No raising of animals shall be allowed after final closure per Rule 15A NCAC 13B
.0543(f)(3) without written approval of DEQ.

6. Post-Closure Cost Estimate Update for 2020 (Table on next page)

V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 8 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
Post-Closure Cost Estimate Update for 2020

Notes:
1. All costs include labor by third party.
2. Water quality monitoring costs are estimated from 2019-2020 budgets.
3. Cost for groundwater wells assumes maintenance of each well every other year.
4. Cost for the gas probes assumes maintenance of each probe every other year.
5. Cost for routine maintenance assumes 1/10 of the cap area will require reseeding
and fertilizing each year.
6. Post Closure Care includes all permitted Phases 1, 2, 3A.
7. Future Phases issued PTO will be added to the closure & Post Closure Care Plans.

END

ITEM UNIT QUANTITY UNIT COST ANNUAL COST
INSPECTIONS/ RECORD KEEPING per trip 4 500.00$ 2,000.00$
MONITORING
Explosive gases (quarterly)per trip 4 400.00$ 1,600.00$
Groundwater/Surfacewater (semi-annually)
Sampling per trip 2 3,000.00$ 6,000.00$
Analysis per trip 2 3,000.00$ 6,000.00$
Reporting per trip 2 2,700.00$ 5,400.00$
Subtotal 19,000.00$
ROUTINE MAINTENANCE (third party)
Mowing ($35/acre) 2 times a year acre 36.6 1,281.00$ 46,884.60$
Reseeding & Fertilize(5)acre 1.8 1,500.00$ 2,700.00$
Vector and Rodent Control acre 18.3 25.00$ 457.50$
Subtotal 50,042.10$
WELL MAINTENANCE
Groundwater Wells lump sum 1 500.00$ 500.00$
Gas Detection Probes lump sum 1 250.00$ 250.00$
Subtotal 750.00$
CAP REPAIR lump sum 1 5,000.00$ 5,000.00$
TOTAL OF ABOVE ITEMS 76,792.10$
ENGINEERING --3%2,303.76$
CONTINGENCY --5%3,839.61$
Annual inflation factor
TOTAL ANNUAL POST-CLOSURE COST (IN 2019 DOLLARS)82,935.47$
TOTAL ANNUAL POST-CLOSURE COST (IN 2020 DOLLARS)1.017 84,345.37$
TOTAL 30 YEAR POST-CLOSURE COST (IN 2020 DOLLARS)2,530,361.13$
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 9 August 2019
Coble’s Sandrock, North Carolina Revised August 2020
APPENDIX A

GROUNDWATER MONITORING WELL MAINTENANCE RECORD

FACILITY: WELL #:

LOCATION: DATE:

INSPECTOR: COMPANY:

1. Is surface water diverted away from the wellhead?

2. Is the concrete pad still intact and free of cracks?

3. Has surface water runoff undercut the concrete pad?

4. Is the outer casing still secure and locked?

5. Is the well identification tag present and is it legible?

a. Does the well identification tag provide the following information:

 The well identification number?
 Drilling contractor name and registration number?
 Total depth of well?
 Depth to screen?
 A warning that the well is not for water supply and that the ground water
may contain hazardous materials.

6. Is the grout between the inner and outer well casings all the way to the ground surface?

7. Is the inner casing firmly grouted in place?

8. Are the inner and outer casings upright and unobstructed?

9. Is water collecting in the outer casing? Does a weep hole need to be bored in the outer
casing to provide drainage?

10. Is the monitoring well accessible by a four-wheel drive vehicle?

11. Have brush and weeds been trimmed so that the well is easy to locate and access?

12. Does the inner well casing have a vented cap?

13. Is the monitoring well visible and adequately protected from moving equipment?
V – Closure & Post-Closure Care Plan Labella Associates, PC C&D LF 5-Year Permit Renewal/LOS 10 August 2019
Coble’s Sandrock, North Carolina

APPENDIX B

POST-CLOSURE INSPECTION RECORD

FACILITY: WELL #:
LOCATION: DATE:

INSPECTOR: COMPANY:

1. Access and Security Control
o Is a notice prohibiting the further disposal of waste materials clearly visible at
the entrance to the facility? o Is the site adequately secured by means of gates, chains, berms, fences or
other security measures to prevent unauthorized entry? o Are the access roads to and within the site maintained to provide access to the
closed disposal area and to all monitoring points?

2. Erosion and Sediment Control
o Is the vegetation adequate to stabilize the site and prevent erosion?
o Are the erosion control measures adequate to prevent silt from leaving the site
and to prevent excessive on-site erosion?
o Do the sediment basins require cleaning out, as indicted by the level of
sediment buildup?

3. Drainage Control Requirements
o Are all areas adequately sloped to promote surface water runoff in a controlled
manner? o Are there areas of observed settlement, subsidence, and/or displacement of
the closure cap? o Are all drainage channels free of accumulated sediment?

4. Uncontrolled Escape of Leachate or Landfill Gas
o Are there any leachate seeps observed? o Are there any signs of uncontrolled releases of landfill gas?

5. Environmental Monitoring Systems
o Are all monitoring wells (gas and groundwater) properly maintained? (Note:
Complete the Groundwater Monitoring Well Maintenance Record during
semiannual sampling events.)

6. Miscellaneous
o Are all site benchmarks marked and evident? o Do vector control measures appear adequate?
V – Closure & Post-Closure Care Plan Labella Associates, PC
C&D LF 5-Year Permit Renewal/LOS 11 August 2019 Coble’s Sandrock, North Carolina

APPENDIX C

LANDFILLGAS MONITORING TEST REPORT

Facility:
Location:
Date of Test:
Weather Condition:
Temperature: Barometric Pressure:
Sampling Personnel:

Monitoring Point Description/Location Time
CH4 / H2S
Concentration
(% of LEL)

From:Kemppinen, Hannu
To:Chao, Ming-tai; Deanna Martin ([e-mail])
Cc:Joyce, Leonard; Davis, Amy; Bertolet, Larry; Stanley, Sherri; Kirchner, Chuck
Subject:[External] RE: Phase 3A Partial closure Report & Permit application - Phases 1-3, 01-05
Date:Tuesday, August 04, 2020 3:13:47 PM
Attachments:image005.emzimage011.pngimage013.pngimage014.pngimage015.pngimage007.pngimage009.pngimage010.png01-05_20200804 Coble C&DLF RTC2 .pdf
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an
attachment to [e-mail]
Ming;

On behalf of Coble’s C&D LF, Labella has prepared the attached document in response to your
email dated July 28, 2020.

Hannu Kemppinen, PG
LaBella Associates | Senior Project Manager

336-790-2252 direct336-323-0092 office
336-209-7156 mobile

From: Chao, Ming-tai <[e-mail]>
Sent: Tuesday, July 28, 2020 11:58
To: Deanna Martin ([e-mail]) <[e-mail]>
Cc: Joyce, Leonard <[e-mail]>; Davis, Amy <[e-mail]>; Bertolet, Larry
<[e-mail]>; Kemppinen, Hannu <[e-mail]>; Stanley, Sherri
<[e-mail]>; Kirchner, Chuck <[e-mail]>
Subject: RE: Phase 3A Partial closure Report & Permit application - Phases 1-3, 01-05

Dear Ms. Martin: FID 1429603I am sorry to hit the wrong button prior to completing the e-mail message. Please disregardthe previous message. Below are the completed ones.

The Solid Waste Section completes a review of the certified partial closure CQA Report (FID1416315 & 1427892) of the Coble’s C&DLF- Phases 1-3A, which is, on your behalf, preparedby LaBella, PC. The certified closure area is 5.6 acres in size. The CQA Report dated July2020 (FID 1427892) acknowledged that several tasks were deviated from the approved CQAplan & Technical Specification (DIN 4862) and made clarification on the concerned matters;therefore, the Solid Waste Section determines the CQA report is acceptable at this time. Thefinal CQA Report (FID 1427914) combining all comments, correspondences and the twoCQA reports is compiled and uploaded to the Laserfiche which can be found in the link: https://edocs.deq.nc.gov/WasteManagement/DocView.aspx?
id=1427914&dbid=0&repo=WasteManagement&searchid=2ea48973-d283-46a1-9974-659f17d80bcd.
After reviewing the revised Facility Plan and Closure/Post-Closure Plan (FID 1427892), theSolid Waste Section has few comments on the plans below:
1. Facility Plan – Section 2, Landfill Capacityi. The approved gross capacity of the CDLF is of 6,935,903 cubic yards (CY). Per Rule 15A NCAC 13B.0537(e)(2), gross capacity is defined as the volumeof the landfill calculated from the elevation of the initial waste placementthrough the top of the final cover, including any periodic cover. Please revisethe statement of gross capacity by including the volume of the proposed 3-feet-thick final cover system and revise the statements of the remaining wastevolume and landfill service life accordingly.
2. Closure Cost EstimateAs stated in Section 2, the approved waste footprint of Phases 1, 2 & 3A is 18.3 acre insize, and the certified closed area is 14.6 acres in size (=4.2+0.9+3.9+5.6). i. Please provide the consistent certified closed area (14.6 vs. 14.73 acres insize).ii. The remaining active disposal area is 3.7 acres in size, not 3.6 acres.iii. Revise the closure cost estimates by using the correct quantity of 3.7 acres tofinalize the cost estimates for a closure.iv. Add a note to the cost item of the earthen material to indicate the borrowsource(s).v. The cost estimate to close the sanitary landfill shall base on the cost of hiring athird party to execute the approved tasks in accordance with the facility'sclosure plan [Rule 15A NCAC 13B. 1802(a)(2)]. The unit cost for each costitem in the closure cost estimate dated July 2020 is far less than that datedDecember 2019, the side-by-side comparison of each unit cost is summarizedbelow. Please explain why the unit cost is reduced.Cost item - Closure Unit Price(12/2019)Unit Price(07/2020)Difference
Mobilization 5,270 5,000 -27018” Clay (10E-5 cm/sec)6 3.5 -2.5
18” Field & Lab testing 2,418 2,294 -124
18” Vegetative Soil 4 3.5 -0.5
Seeding/Revegetation 1,581 1,500 -81
Gas Vent Installation 5,500 0 -5,500E&S/Stormwater BMPs 85,000 0 -85,000
Survey 1,581 1,500 -81 3. Coble’s Sandrock, Inc. shall provide additional financial assurance (FA) / closure costestimate for each of the waste storage, treatment, and process units. Except those non-disposal units listed in Rule 15A NCAC 13B. 1801(a) effective July 1, 2020, thefollowing non-disposal solid waste management units listed in the Operations Plandated August 2019, shall provide FA/closure cost estimate according to Rule 15ANCAC 13B. 1802(a)(1):
· Wood wastes including recovered from C&D waste stream – clean unpaintedlumber, plywood/engineering wood, pallets, woody components fromdestructed mobile homes etc. (yard waste and land clearing and inert debris areexcluded)
· Scrap tires.
· Scrap metals including white goods, metal components from destructed mobilehomes.
· Cardboard boxes.
· Post-consumer asphalt shingles, and
· Any other recovered wastes stored on-site.
i. Pursuant to Rule 15A NCAC 13B .1802(a)(1), Coble’s Sandrock, Inc. shallprovide the FA and supporting calculations of the costs for closing each unitthat listed in the Operations Plan. The closure cost estimate shall be calculatedby multiplyinga. The maximum tonnage of waste (noted with dimensions of each stockpile)permitted to be stored at the on-site location (noted with extent of storageunit in square feet, square yards or acres) at any given day byb. The cost per ton for a third party to remove the waste, transport it, anddispose of it at the nearest facility permitted to receive such waste.ii. Coble’s Sandrock, Inc. shall annually adjust the closure cost estimate and theamount of financial assurance for inflation, establish and maintain financialassurance for closure of the facility and according to Rules 15A NCAC 13B.1802(b), (c) & (d). Please timely respond the comments. If you have any questions or request furtherclarifications on the comments, please contact me. Thanks.

From: Chao, Ming-tai
Sent: Tuesday, July 28, 2020 11:30 AM
To: Deanna Martin ([e-mail]) <[e-mail]>
Cc: Joyce, Leonard <[e-mail]>; Davis, Amy <[e-mail]>; Bertolet, Larry
<[e-mail]>; Kemppinen, Hannu <[e-mail]>; Stanley, Sherri
<[e-mail]>; Kirchner, Chuck <[e-mail]>
Subject: Phase 3A Partial closure Report & Permit application - Phases 1-3, 01-05

Dear Ms. Martin:
The Solid Waste Section completes a review of the certified partial closure CQA Report (FID1416315 & 1427892) of the Coble’s C&DLF- Phases 1-3A, which is, on your behalf, prepared
by LaBella, PC. The certified closure area is 5.6 acres in size. The CQA Report dated July
2020 (FID 1427892) acknowledged that several tasks are deviated from the approved CQAplan & Technical Specification (DIN 4862); therefore,

From: Kemppinen, Hannu <[e-mail]>
Sent: Friday, July 24, 2020 11:14 AM
To: Chao, Ming-tai <[e-mail]>; Stanley, Sherri <[e-mail]>
Cc: Deanna Martin ([e-mail]) <[e-mail]>; Joyce, Leonard
<[e-mail]>; Davis, Amy <[e-mail]>; Bertolet, Larry
<[e-mail]>
Subject: RE: [External] Comment_ 0105-CDFL-1998, 2020619 Phase 3A Partial closure Report

CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an
attachment to [e-mail]

Hi Ming:
On behalf of Coble’s CDLF, LaBella has prepared responses to the Phase 3A partial closure
report received on June 24, 2020. The attached document includes revisions to the 3A closure
report, Facility Plan and Closure & Post Closure Care Plan. We understand Coble will provide the
financial assurance mechanism based on the revised closure and post-closure care plans thru
their bonding company.

We hope these prepared documents combined in this submittal will provide all the information
to the Section to accept the 3A partial closure and prepare permit to continue operate the CDLF
landfill. Thank you for your assistance in the preparation of these documents.

Hannu Kemppinen, PG
LaBella Associates | Senior Project Manager

336-790-2252 direct
336-323-0092 office
336-209-7156 mobile

From: Chao, Ming-tai <[e-mail]>
Sent: Monday, July 20, 2020 12:41
To: Kemppinen, Hannu <[e-mail]>
Cc: Deanna Martin ([e-mail]) <[e-mail]>; Joyce, Leonard
<[e-mail]>; Davis, Amy <[e-mail]>; Bertolet, Larry
<[e-mail]>; Stanley, Sherri <[e-mail]>
Subject: RE: [External] Comment_ 0105-CDFL-1998, 2020619 Phase 3A Partial closure Report

Hi Hannu:
I knew that Coble closed out some Phase 3A landfill area as shown on the closure CQA report
dated June 2020. But the Phase 3 permit application including Facility and C&PC Plans mustreflect the latest changes which, as the basis, will be incorporated into the new permit
conditions. Attached is the latest Closure and Post-closure Plan (C&PC Plan) dated December2019 and prepared by LaBella, and you can see the inconsistent info existing in the plan.

I received a bond rider/FA amount effective 11/05/2019 which must be the same as theamounts in cost estimates in C/PC & PACA. Please let me know if you have any further
questions of the requests.

From: Kemppinen, Hannu <[e-mail]>
Sent: Monday, July 20, 2020 12:02 PM
To: Chao, Ming-tai <[e-mail]>
Cc: Deanna Martin ([e-mail]) <[e-mail]>; Joyce, Leonard
<[e-mail]>; Davis, Amy <[e-mail]>; Bertolet, Larry
<[e-mail]>
Subject: [External] Comment_ 0105-CDFL-1998, 2020619 Phase 3A Partial closure Report

CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an
attachment to [e-mail]

Ming,
While we are finalizing the Coble 3A closure submittal, and reviewing your (below) introduction
paragraph, we have questions needing clarification regarding “revised permit renewal
application and financial assurance mechanism.”

Responses to the permit renewal comments was submitted to the Section in November 1, 2019
and the attached response was received on January 2020 stating “two major issues prevent
permit being issued.”
1. Property deed information and financial assurance.
Coble provided the deed map on January 17, 2020, and it was acceptable to the
Section.
2. Financial assurance was said to be pending the Phase 3A partial closure until the
work would be completed, and then the FA would be revised.
We have revised closure and post closure plans to be submitted with the 3A Closure
report response letter submittal.

I had talked about the FA revision with Sarah Rice in March 2020 and it was our
understanding that the closure & post-closure plans and FA will be finalized after the
phase 3A closure was completed. Coble plans to continue the same financial
mechanism as in past with revised acreages closed and active operation.

Your advise will be much appreciated,

Hannu Kemppinen, PG
LaBella Associates | Senior Project Manager

336-790-2252 direct
336-323-0092 office
336-209-7156 mobile

From: Chao, Ming-tai <[e-mail]>
Sent: Wednesday, June 24, 2020 14:43
To: Deanna Coble Martin <[e-mail]>
Cc: Kirchner, Chuck <[e-mail]>; Stanley, Sherri <[e-mail]>;
Kemppinen, Hannu <[e-mail]>; Joyce, Leonard <[e-mail]>;
Davis, Amy <[e-mail]>
Subject: Comment_ 0105-CDFL-1998, 2020619 Phase 3A Partial closure Report

Dear Deanna:
FID 1416315
After completing a review of the June 2020 CQA report (FID 1416315) for a partialclosure of the Coble’s C&DLF, Permit No. 0105-CDLF-1998, the Solid Waste Section hasseveral comments below. Please respond the comments in writing and submit a final CQAreport for this 5.6-acre partial closure activity and the revised permit renewal applicationfor Phase 1 thru 3 of the C&DLF including and the rule-required financial assurancemechanism before July 24, 2020. If you have any problem to produce the requesteddocuments by the date of July 24, 2020 for a reasonable cause please contact myself for anew submittal date within five (5) working days (by June 30, 2020) after receiving this e-mail message. The existing permit (DIN 25405) for operating Coble’s C&DLF expired onSeptember 02, 2019, and the Solid Waste Section will revoke the permit and enforce thesite closure on September 02, 2020 if the requested documents/applications are notsubmitted in time for approval. This permit decision was originally sent to your attentionvia an e-mail message on January 08, 2020 (FID 1387209).

The comments on the 5.6 acre partial closure CQA Report are:
1. (Sections 1 & 2.2.4) The partial closure report (DIN 24357) and the Phase 3 renewalapplication dated December 2019 (FID 1378626) stated that the disposal area of 9.13acres was partially closed, not 9.8 acres. The total acreage of partial closure areas of theC&DLF shall be 14.73 acres (= 9.13+5.6). Please provide the correct closure acreage.

2. (Section 2.2) This Section states that “the surveyor verified the existing intermediatecover thickness to be a minimum of 12 inches prior to Coble commencing theconstruction of low permeability infiltration soil layer.” There are no survey data inAppendix 3 to confirm that the thicknesses of intermediate cover over the 5.6-acreclosure area meet the specified requirement. Please provide survey data.

3. (Section 2.2.1) According to the CQA plan (including Table 1) and TechnicalSpecifications of the approved Phase 3 PTC application dated March 2008 (DIN 4862),the report does not include the following testing results:
i. Construction and QA/QC testing results associated with the test pad of the 18-inch-thick infiltration layer [Sections 02218 & 02229 of the approvedTechnical Specifications (DIN 4862)].
ii. Please explain the discrepancy of number of tests described in Section 2.2.1and those shown in Appendices 1 & 2.
Test item Section 2.2.1 Appendices 1 & 2
K, from Shelby tube 18 18
K, from remold sample 2 1
PI NA 1
Standard Proctor NA one point method - 1
In-place density & moisturecontent (nuclear gauge)30 106 tested and 96passed
In-place density & moisturecontent (drive cylinder)18 21 tested and 19 passed
iii. The Engineering Plan and Technical Specification Sections 02224 & 02227and Table 1 (DIN 4862) require the final soil cover system pertaining aminimum friction angle of 26.6 degree by ASTM D4767. Please provide thetesting result in the CQA report.

4. (Section 2.2.2) The results of testing, per requirement listed in Table 1(DIN 4862), onthe protective soil layer/erosion layer are not available in the CQA report. Pleaseprovide the test results.

5. (Section 2.2.3)
i. The gas well diameter and the depth deviate from the approved ones (DIN17384). Please explain who approves the deviation and why the approval isacceptable by the Solid Waste Section.
ii. This Section states that “for the Phase 3A closure, Coble installed six passivegas vents in a C&D landfill, excavated pits thru the cover and infiltrationlayers to place perforated PVC pipes in the top layer of the waste.” Additionally, the photos in Appendix 2 clearly show that areas for installinggas vent were excavated after the final soil cover was completed installed. Thegas vent construction destroys the constructed soil cover; therefore, the soiltesting (including, but not limited to in-pace density & moisture content andhydraulic conductivity) on each lift per layer must be properly conducted todemonstrate the final cover is successfully restored.

6. (Appendix 1, page 9 of 207)
i. The maximum dry density for soil sample CL-1 (Lab ID 2020-019-001-001) is
95.6 pcf. Please correct the typo in the summary table including the % of thecompaction effort.
ii. According to Table 1 (DIN 4862), the following soil testing at the frequencyof one test per 10,000 CY is required, but the Lab testing results are notavailable in the CQA report. The required tests are:
Particle size (ASTM D422 & D1140), soil classification (ASTM D 2487),moisture content (ASTM D2216), PI (ASTM D4318), Standard Proctor(ASTM D698).

7. (Appendix 2, page 137 of 207) The in-place density test results at the Acre 13 (lift 1) &Acre 12 (Lift 3) that are summarized in Field Daily Report dated 11/26/14 failed to meetthe specified compaction effort - 95% maximum dry density.

8. (Appendix 2, page 150-151)
i. The in-place density test results at the Acre 13 (lift 3) are failed to meet thespecified compaction effort - 95% maximum dry density.
ii. The density results of sample DC-1 showed on the summary table areinconsistent to those in lab report on page 151.

9. (Appendix 3)
i. The survey points to measure the thickness of each layer of the final cover arenot available on the attached drawing sheets.
ii. The partial closure activities were not completed until March 09, 2020(Referring Section 2.2), but the as-built survey was certified by the licensedsurvey dated October 10, 2019. Why the as-built survey is permissible?

Please contact me if you have any question of the comments.

From: Chao, Ming-tai
Sent: Friday, June 19, 2020 2:57 PM
To: Deanna Coble Martin <[e-mail]>
Cc: Kirchner, Chuck <[e-mail]>; Stanley, Sherri <[e-mail]>;
Kemppinen, Hannu <[e-mail]>
Subject: RE: [External] 0105-CDFL-1998 2020619 Phase 3A Partial closure Report

Dear Mrs. Martin: The Solid Waste Section receives the electronic copy of the CQA report for Phase 3A partialclosure; this report is uploaded to Laserfiche with a FID 1416315. Have a wonderful day.

From: Kemppinen, Hannu <[e-mail]>
Sent: Friday, June 19, 2020 1:25 PM
To: Chao, Ming-tai <[e-mail]>
Cc: Deanna Martin ([e-mail]) <[e-mail]>;
[e-mail]; Joyce, Leonard <[e-mail]>
Subject: [External] 0105-CDFL-1998 2020619 Phase 3A Partial closure Report

CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an
attachment to [e-mail]

Ming,
On behalf Coble’s CDLF, LaBella has prepared the attached Phase 3A partial closure report for
the Solid Waste Section review. Following the partial closure certification by the Section, we will
update the landfill closure and post-closure care plans, and financial assurance. To prepare
these proposed updates, we have asked Coble to prepare the annual Solid Waste Report 2020
with annual tonnage data and updated survey. These data will be incorporated to update the
closure and post-closure care plans and the annual financial assurance in accordance with 13B
.0546.

Thank you for your assistance with the Coble’s CD landfill operations and finalizing the permit
renewal process that has been underway for quite some time. Should you have questions
regarding the submitted report, we are available to help and provide clarification.

Thank you and have a great summer weekend.

Hannu Kemppinen, PG
LaBella Associates | Senior Project Manager
336-790-2252 direct
336-323-0092 office
336-209-7156 mobile
2211 West Meadowview Road, Suite 101
Greensboro, NC 27407
labellapc.com [labellapc.com]