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HomeMy WebLinkAboutNCD024900987_20230424_Holcomb Creosote Company_Remedial Action Work PlanRemedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 Final REMEDIAL ACTION WORK PLAN Holcomb Creosote Company Site, Yadkinville, Yadkin County, North Carolina April 24, 2023 Prepared for Environmental Protection Agency Atlanta Federal Center 61 Forsyth Street, SW Atlanta, Georgia 30303 Prepared by Environmental Restoration, LLC 1666 Fabick Drive St. Louis, Missouri 63026 Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 TABLE OF CONTENTS 1. Introduction ........................................................................................................................ 1-1 1.1 Proposed Action ............................................................................................................. 1-1 1.2 Project Objectives .......................................................................................................... 1-1 2. Background ........................................................................................................................ 2-2 2.1 Site History ..................................................................................................................... 2-2 2.2 Previous Investigations .................................................................................................. 2-3 2.2.1. Soil Contamination .............................................................................................. 2-4 3. Project Overview ................................................................................................................ 3-5 3.1 Soil Remedy Components.............................................................................................. 3-5 3.2 Groundwater Remedy Components ............................................................................. 3-5 4. Remedial Action Activities ................................................................................................ 4-5 4.1 Pre-Mobilization Activities ........................................................................................... 4-6 4.1.1. Procurement ......................................................................................................... 4-6 4.1.2. Submittals ............................................................................................................. 4-7 4.2 Mobilization and Site Preparation ............................................................................... 4-8 4.2.1. Temporary Field Office and Support Facilities ................................................ 4-8 4.2.2. Clearing and Grubbing ....................................................................................... 4-9 4.2.3. Survey Data and Property Boundaries .............................................................. 4-9 4.2.4. Utilities .................................................................................................................. 4-9 4.2.5. Establish Work Zones ....................................................................................... 4-10 4.2.6. Stabilize Construction Entrance ....................................................................... 4-11 4.2.7. Stabilize Access and Haul Roads ...................................................................... 4-11 4.2.8. Erosion Control Measures ................................................................................ 4-11 4.2.9. Site Security and Fencing .................................................................................. 4-12 4.2.10. Equipment Decontamination .......................................................................... 4-12 4.2.11. Waste Management ......................................................................................... 4-12 4.3 Demolition Activities .................................................................................................... 4-12 4.3.2. Lead Stabilization Activities ............................................................................. 4-14 4.3.3. Structure and Site Demolition .......................................................................... 4-15 4.3.4. Well Abandonment ............................................................................................ 4-16 4.4 Transportation and Disposal (T&D) Operations ...................................................... 4-18 4.4.1. Recycling ............................................................................................................. 4-18 4.4.2. C&D Building Debris / Trash ........................................................................... 4-19 4.4.3. Transformer ....................................................................................................... 4-19 4.4.4. ACM -Asbestos Contaminated Material ......................................................... 4-19 4.4.5. Lead ..................................................................................................................... 4-19 4.4.6. Injection Soil Borings [If Needed] .................................................................... 4-19 4.4.7. Manifest Tracking & CERLCA Reporting ..................................................... 4-19 4.5 Groundwater Injection Activities -Phase 1................................................................ 4-20 4.5.1. Injection Procedures, Locations, and Depths .................................................. 4-20 4.5.2. Materials for Injections ..................................................................................... 4-22 4.5.3. Injection Dosage ................................................................................................. 4-22 4.5.4. Surveying ............................................................................................................ 4-23 4.6 Soil Excavation and On-site Consolidation ............................................................... 4-23 Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4.6.1. Soil Excavation Delineation .............................................................................. 4-23 4.6.2. Temporary Soil Stockpile Construction .......................................................... 4-24 4.6.3. Excavation -Clean Overburden ........................................................................ 4-24 4.6.4. Excavation -Contaminated Soil ........................................................................ 4-24 4.6.5. Consolidation ...................................................................................................... 4-24 4.6.6. As-Excavated Survey ......................................................................................... 4-25 4.6.7. Rough Grade Backfill and Compaction ........................................................... 4-25 4.6.8. Restoration ......................................................................................................... 4-26 4.7 NAPL-Impacted Soil Stabilization ............................................................................. 4-27 4.7.1. Mix Design .......................................................................................................... 4-27 4.7.2. Soil Stabilization Process ................................................................................... 4-27 4.7.3. NAPL Soil Inside Containment Cell ................................................................ 4-27 4.7.4. NAPL Soil Outside Containment Cell ............................................................. 4-28 4.7.5. Solidification QC Testing .................................................................................. 4-28 4.8 Construction of Engineered Cap ................................................................................ 4-28 4.8.1. Liner System Installation .................................................................................. 4-29 4.8.2. 18” Soil Layer ..................................................................................................... 4-30 4.8.3. 6” Topsoil ............................................................................................................ 4-31 4.8.4. Install Rip Rap / Drainage Features ................................................................ 4-31 4.8.5. As-built Survey of Cap/Containment ............................................................... 4-31 4.9 Site Restoration Activities ........................................................................................... 4-32 4.9.1. Containment Cell ............................................................................................... 4-32 4.9.2. ISS Locations ...................................................................................................... 4-32 4.9.3. Fence Installation ............................................................................................... 4-33 4.9.4. Surveys ................................................................................................................ 4-33 4.10 Demobilization.............................................................................................................. 4-33 4.11 GROUNDWATER INJECTION ACTIVITIES -PHASE 2 .................................... 4-33 5. Remedial Action report ................................................................................................... 5-34 6. References ......................................................................................................................... 6-35 TABLES 3-1 Cleanup Levels 4-1 Groundwater Treatment Locations and Quantities FIGURES 2-1 Site Location 2-2 Site Facility Plan 3-1 Project Schedule 4-1 Temporary Site Facilities Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 LIST OF APPENDICES Appendix A Contractor Quality Control Plan Appendix B Erosion and Stormwater Control Plan Appendix C Final Remedial Design Soil Excavation and Solidification/Stabilization Drawings Appendix D Final Remedial Design Groundwater Injection Drawings Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 1-1 1. INTRODUCTION This document was prepared by Environmental Restoration, LLC (ER LLC) for the U.S. Environmental Protection Agency, Region 4 – under its Emergency and Rapid Response Services (ERRS) contract, Contract No. 68HE0421D0015, Task Order No. 68HE0422F0073, in accordance with the order for supplies and services dated August 10, 2022 authorizing remedial action as part of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Remedial Action at the Holcomb Creosote Company (HCC) Site located in Yadkinville, Yadkin County, North Carolina. 1.1 PROPOSED ACTION This remedial action is being conducted in accordance with the ERRS IV Fair Opportunity Submission Request (FOSR) and Statement of Work for the Holcomb Creosote Site (HCC) dated June 14, 2022, the attached 90% Soil Remedial Design for HCC and 30% Groundwater Remedial Design for HCC, with ER’s Proposal for the FOSR, dated July 8, 2022 and in accordance with the Record of Decision for the Holcomb Creosote Company Superfund Site, dated August 2018 (ROD). The Final 100% Soil Remedial Design Holcomb Creosote Company Site (Soil RD) and Final 100% Groundwater Remedial Design Holcomb Creosote Company Site (Groundwater RD), prepared by HydroGeoLogic, Inc (HGL) and dated December 2021 and August 2022, respectively were subsequently made available to ER. Every effort has been made to conform with these finalized documents. The remainder of this document will address the means, methods, procedures, and general guidelines to perform this action. 1.2 PROJECT OBJECTIVES The objective of this project is implementation of the selected remedy, which is a combination of excavation of contaminated soil/sediment, disposal in an on-site containment cell, in-situ solidification/stabilization of NAPL impacted soil, and in-situ treatment of groundwater using In-Situ Chemical Oxidation (ISCO) to reduce Contaminants of Concern (COCs) to below cleanup levels. According to the ROD, based on the information available, the EPA and the North Carolina Department of Environmental Quality (NCDEQ) believe that the Selected Remedy satisfies the following statutory requirements of CERCLA Section 121(b): 1) protects human health and the environment; 2) complies with applicable or relevant and appropriate requirements (ARARs); 3) is cost effective; 4) utilizes permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable; and 5) satisfies the preference for treatment as a principal element. The Selected Remedy will achieve substantial risk reduction in a reasonable time frame. The remedial activities including excavation, treatment where appropriate and disposal in the containment cell will take place within the area of concern. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 2-2 Quality control requirements for the HCC Remedial Action are addressed in the Project Contractor Quality Control (CQC) Plan, presented as Appendix A of this document. The CQC reflects company commitment to quality and is the blueprint for ensuring quality deliverables for the Remedial Action. The CQC identifies requirements and assigns responsibilities for ensuring that the project objectives are met. To do this, it describes or references the controls, quality procedures and processes, and guidelines to be followed. 2. BACKGROUND The HCC Site is located at 5016 U.S. Highway 601, just north of Yadkinville in Yadkin County, North Carolina (Figure 2.1). The geographic coordinates of the Site, as measured near the former concrete storage pit, are latitude 36.1579° North and longitude 80.6752° West. The office building and storage building, located on the western portion of the property along U.S. Highway 601, are the only structures remaining at the Site. Structures formerly located on HCC included the creosote storage tanks, pressure treatment vessel, drip pad and sump, canopy covering the drip pad, concrete storage pit, steel settling tank, distillation evaporator, and untreated and treated wood storage areas. The location of these Site features within the former operations area is shown in Figure 2.2. HCC conducted wood treating operations on the property from 1951 to 2009. In 2011, HCC was referred to EPA’s Superfund program to address known and potentially hazardous waste contamination under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The Site was placed on the National Priorities List in 2012. 2.1 SITE HISTORY From 1951 to 2009, HCC operated a wood treating facility on the Site property. HCC manufactured pressure-treated posts and lumber using creosote coal tar solutions. During facility operations, wood products were placed into a pressurized treatment vessel and heated with steam to open the pores of the wood and remove sap and resin. After an allotted time, the vessel was vented to decrease the interior pressure, and a vacuum was drawn to remove moisture. Following application of the vacuum, creosote was forced into the pores of the wood. The vapor stream from the treatment vessel was passed through a condenser, where the water and creosote mixture was then liquefied. After treatment, condensate from the condenser and from depressurization of the treatment vessel was pumped to a concrete-lined settling tank (i.e., the concrete storage pit). This liquid was pumped from the concrete storage pit to a steel settling tank, where the solids settled to the bottom. The liquids were then pumped to an unlined surface impoundment for storage and evaporation. After treatment, the wood was transported to a drip pad immediately south of the treatment vessel, where it was allowed to drip dry. In the early 1990s, HCC reportedly ceased using the drip pad; instead, the wood was allowed to dry inside the treatment vessel and was then moved to a transfer area located at the end of the treatment vessel. The transfer area measured approximately 25 feet (ft) by 100 ft and consisted of soil and gravel over a plastic liner and covered by a metal roof. One 55-gallon sump was located at each end of the treatment vessel to contain any spills that occurred when the treatment vessel doors were opened. Spilled creosote was pumped back into the treatment vessel to contain any spills that occurred when the treatment vessel doors were opened. Spilled creosote was pumped back into the treatment vessel. A catch basin was also located at the end of the treatment vessel where the treated lumber was removed. The treatment vessel was cleaned Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 2-3 from time to time to remove buildup of creosote and solids. This sludge-like waste was removed and placed in 55-gallon containers that were stored in the drum storage area until they were shipped off Site for disposal. The surface impoundment, located at the southeastern corner of the facility, reportedly was 30 ft by 60 ft by 6 ft deep (approximately 80,000-gallon capacity) and was used by HCC to store liquid waste until 1983. The surface impoundment contained waste classified as EPA hazardous waste K001: “bottom sediment sludge from the treatment of wastewaters from wood preserving processes that use creosote and/or pentachlorophenol.” Before 1981, HCC constructed a 0.587-acre land farm on the east side of an unnamed tributary of North Deep Creek, east of the operations area. Residual liquids from the surface impoundment were pumped to the land farm, where an irrigation system was used to spray liquids onto the land surface. The land farm was utilized when weather conditions did not allow for evaporation in the surface impoundment and when the surface impoundment was near its storage capacity. From 1982 to 1983, the land farm was used as a remediation unit for disposal of K001-contaminated sludge and wastewater removed during closure of the surface impoundment. 2.2 PREVIOUS INVESTIGATIONS Groundwater monitoring at the HCC site began in 1982 with the installation of three monitoring wells in the shallow regolith aquifer beneath the HCC site. Groundwater assessment was initiated to determine the magnitude and extent of creosote-related contamination. Following closure of the surface impoundment and construction of the land farm, additional wells were installed in the downgradient (southeast) comer of the surface impoundment and around the land farm perimeter. Testing of these wells indicated contamination; therefore, the groundwater assessment was expanded. A Corrective Action Plan was prepared in 1996, containing a proposed remedial design (RD) to limit the migration of the hazardous constituents in the groundwater system that had resulted from releases from the hazardous waste management units, namely the surface impoundment, land farm, and drip pad. Wells were sampled annually from 1995 to 2005. Wells located within the backfilled surface impoundment and just east of the former impoundment contained the highest concentrations of site-related contaminants throughout the 10-year sampling history. These primarily included Polycyclic aromatic hydrocarbons (PAHs) and petroleum volatile organic compounds (VOCs), potentially originating from the historical use and storage of creosote and/or diesel oil at the HCC site. PAH sampling results indicated exceedances of the appropriate Safe Drinking Water Act Maximum Contaminant Levels (MCLs), North Carolina groundwater quality standards, and/or background concentrations. In November 2009, the NCDEQ conducted a SI of the HCC site and noted several areas of concern including the treatment vessel, 55-gal sump, catch basin, transfer area and underlying soils, concrete storage pit, aboveground storage tanks (ASTs), and approximately 30 55-gal containers. Several NOVs were issued by the NCDEQ. In January 2011, the EPA conducted a removal site evaluation, during which the EPA noted heavily stained soil throughout the process area; waste creosote and process sludge in the concrete storage pit; a leaking 1,000-gal above-ground storage tank (AST); two 10,000-gal creosote tanks containing approximately 5,600 and 8,500 gal of creosote, respectively; and a visible sheen in the Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 2-4 unnamed tributary of North Deep Creek. The investigation led to the EPA initiating an ER to mitigate the ongoing release of hazardous substances (ER activities were conducted from January 22, 2011 to September 27, 2011). In May 2011, the EPA conducted an SI at the HCC site. The EPA collected surface soil samples within the suspected footprint of the former surface impoundment and the area of the former land farm. Sediment samples were also collected from the unnamed tributary of North Deep Creek. Sample results indicated high concentrations of PAHs in the site soils and sediments. In August 2011, the EPA Region 4 Science and Ecosystem Support Division (SESD) conducted a wetlands delineation study at the HCC site. An EPA-led Remedial Investigation (RI) was conducted for the Site between 2012 and 2017. The following subsections present a summary of the nature and extent of contamination at the Site as characterized by the RI. 2.2.1. Soil Contamination Semi volatile organic compounds (SVOCs), mainly PAHs, are present in soils throughout the former operations area, land farm, and the southern portion of the unnamed tributary before entering the wetlands. Benzo(a)pyrene and naphthalene are the main COCs in soil. The extent of soil contamination is generally defined by the extent of naphthalene exceeding its Site-specific groundwater protection value of 180 micrograms per kilogram (μg/kg). The extent and depth of soil contamination presented in the RI was updated with additional data collected during the pre- RD field investigations and can be found in the Final Soil Data Evaluation and Conceptual Site Model Update Technical Memorandum and Section 3.3 of the Soil RD report. Sediment Sediment samples were collected during the RI from Dobbins Pond, the unnamed tributary, and the wetlands. The only COC identified in sediment was total PAHs. Only one sediment sample, HCSD47 located just south of the land farm in the unnamed tributary north of the wetlands, exceeded the maximum acceptable toxicant concentration of 198 milligrams per kilogram (mg/kg) total PAHs calculated from Site-specific soil invertebrate toxicity testing. Groundwater Naphthalene is the main COC in the groundwater; however, there are co-mingled plumes of other COCs including dibenzofuran, cobalt, manganese, iron, and 2-methylnaphthalene. Groundwater contamination is most prevalent in the saprolite and partially weathered rock (PWR) in the area between the east and southeast sides of the main building and west side of the unnamed tributary. There is very little groundwater contamination near the land farm or in the bedrock. The extent of groundwater contamination is generally defined by the extent of naphthalene exceeding its North Carolina groundwater standard of 6 micrograms per liter. The extent of groundwater contamination presented in the RI was updated with additional data collected during the pre-RD field investigations and can be found in the Soil RD and Groundwater RD Reports. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-5 3. PROJECT OVERVIEW This section provides an overview of the soil and groundwater RA components, describes the technical parameters upon which the design will be based, and identifies the requirements and standards upon which the remedial action is based. The EPA issued ROD, dated August 2018, established cleanup levels for soil, sediment, and groundwater, and selected a remedy for the Site. The Site cleanup levels are summarized in Table 3-1. The selected remedy components addressed by this RAWP include demolition of onsite structures in addition to soil and groundwater components. 3.1 SOIL REMEDY COMPONENTS • Excavation of contaminated soil outside of the previously closed and capped land farm and surface impoundment areas and proposed containment area, within an Area of Contamination (AOC), as required to mitigate human exposure and additional leaching of contaminants into the surficial aquifer. The excavated areas will be backfilled with uncontaminated soil obtained from an off-Site borrow source. The excavated wetlands will be restored. • Consolidation of excavated soil into an on-site capped containment cell which is proposed to be located within the former operations area. Excavated soils/sediments impacted with non-aqueous phase liquid (NAPL) will be treated within the containment area using in situ solidification/stabilization (ISS) technology to reduce the mobility of COCs by eliminating free liquids and to stabilize the containment cell. The proposed containment cell will be capped using an RCRA-type multi-layered cap that meets the RCRA Subtitle C landfill requirements for a final cover. • Maintenance of the existing RCRA caps over the closed land farm and surface impoundment including regrading to establish adequate thickness, repair, and revegetation. These areas also will be fenced to restrict access. A review of Site conditions and risks will be conducted every five years if contamination remains on site above levels that allow for unlimited use and unrestricted exposure. The caps will be inspected at least annually, and repairs made when needed. 3.2 GROUNDWATER REMEDY COMPONENTS • Although the ROD initially called for both ISCO and ISEB components to the groundwater remedy, based on the pilot test observations, HGL determined that the RA component of ISCO is not needed and that the HCC Site groundwater can be treated solely with ISEB. • Aerobic in situ enhanced bioremediation (ISEB), using the reagent PermeOx® Ultra, a calcium peroxide, calcium hydroxide mixture, will be implemented. The goal of the in-situ treatments is the restoration of groundwater throughout the plume beyond the waste management areas to attain federal and more stringent state drinking water standards based on the designated beneficial use of the aquifer as a potential drinking water source. 4. REMEDIAL ACTION ACTIVITIES The objective of this project is implementation of the selected remedy, which is a combination of Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-6 groundwater injection of ISEB reagents, excavation of contaminated soil/sediment, disposal in an on-site containment cell, and in-situ solidification/stabilization of NAPL impacted soil to reduce COCs to below cleanup levels. 4.1 PRE-MOBILIZATION ACTIVITIES 4.1.1. Procurement Prior to mobilization, ERwill have commenced procurement of necessary resources to complete the Statement of Work (SOW.) ER has or will contact vendors of selected services to solicit, and document, competitive quotes for services and/or supplies. Request for Quotations (RFQ) will be submitted to vendors based on the specific site need and if value will exceed $10,000. The table below identifies items ER anticipates will be needed to complete the SOW. This list provides a summary of these items and the procurement process to obtain the services and supplies. If the final award has been made the Vendor’s name is included. Item Service or Supplies Vendor Surveyor Topographical / As-builts Competitive Procurement -RFQ Security Services On-site Security Competitive Procurement -RFQ Fence Subcontractor Fence / Gate Competitive Procurement -RFQ Injection Subcontractor Injection of reagent per RD Competitive Procurement-Geologic Exploration Injection Reagent PermeOx Ultra Evonik -Sole Source Proprietary Erosion Supplier Erosion Control Materials Competitive Procurement Cement Supplier Portland Cement Competitive Procurement -RFQ Geophysical Subcontractor Compaction Testing Competitive Procurement -RFQ Laboratory Sample Analysis Competitive Procurement Sanitation Subcontractor Sanitation units / hand wash Competitive Procurement Electrical Subcontractor Install Temp. Electric Service Competitive Procurement Transportation and Disposal Debris—trees / brush Competitive Procurement -RFQ Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-7 C&D -Building/Concrete Competitive Procurement – AWMSI to WM Great Oak Landfill ACM Competitive Procurement – First Piedmont Corp Landfill Transformer Competitive Procurement – Emerald Transformer Lead Competitive Procurement – AWMSI to WM Emelle Equipment Excavator/s Competitive Procurement -RFQ Dozer Competitive Procurement -RFQ Water Truck Competitive Procurement -RFQ Off-road Dumps-tracked Competitive Procurement -RFQ Office / Storage Trailers Competitive Procurement Skid Steer->10k Competitive Procurement Brush cat attachment Competitive Procurement Water Truck-2,000gal [min.] Competitive Procurement Hauling Subcontractor Backfill Competitive Procurement -RFQ Topsoil Competitive Procurement -RFQ Rock Competitive Procurement -RFQ Fuel Subcontractor Fuel / Temporary Storage Tank Competitive Procurement -RFQ Liner Subcontractor Liner Installation Competitive Procurement-RFQ 4.1.2. Submittals During the pre-mobilization period, the ER project team will prepare and submit for approval the following deliverables: • Project Health and Safety Plan (HASP) -Submitted 1/4/23 (pending approval) • Construction Quality Control (CQC) Plan -Submitted 1/4/23 (pending approval) • Remedial Action Work Plan (RAWP) -Submitted herein. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-8 o Project Schedule (Contained within the RAWP) • Requests for Quotations (RFQ), Bid Analyses, and Consent Packages -as required. Upon mobilization and throughout the duration of the task order period of performance, ER will submit to EPA contract and task order specific deliverables as required. These items include but are not limited to the following: • Daily Work Orders • Removal Cost Management System (RCMS) 1900-55s • Personnel COI • CERCLA Off-site Disposal Reports • Subcontract Consent Requests 4.2 MOBILIZATION AND SITE PREPARATION ER will begin mobilization and site setup as coordinated and approved by EPA. It is anticipated to begin site mobilization on March 20, 2023, or upon approval of all project deliverables. ER anticipates one mobilization for RD Phase 1 operations and a second mobilization for the RD Phase 2 injection operations. On-site resources, personnel and equipment, will fluctuate based on the tasks being performed, with resources being mobilized and demobilized to minimize cost and maximize on-site utilization. The following provides details on the mobilization and site preparation tasks prior to injection and excavated soil operations. 4.2.1. Temporary Field Office and Support Facilities Upon mobilization, ER will set up a command post area on site utilizing the former parking lot areas. The trailer will be placed near the entrance to the site, north of the access to Hwy 601 and adjacent to the work areas. This area will consist of office and storage trailers [Conex boxes], laydown area for equipment, material storage, and appropriate sanitation facilities. ER will install power from an installed meter pole to power the command post area. A single shared office trailer will be designated for EPA, HGL, and state officials, with a second trailer for ER on-site staff. The locations of the temporary field offices and support facilities are depicted on Figure 4-1. An area of the command post will be designated as a storage area for a Conex box for routine supplies and small equipment storage and include an area for a aboveground storage tank [>500gals] for diesel. The fuel storage tank shall have secondary premanufactured containment provided by the fuel supplier, which can contain a minimum of 100 percent of the tank(s) volume and can contain any potential spills during filling or while stored. In accordance with Section 01 57 19 Section 3.7.4 of the RD Specifications, ER will Maintain spill cleanup equipment and materials at the work site. A spill kit consisting of an 85-gallon salvage drum containing 5” boom and two bails of absorbent pads will be staged adjacent to the storage tank. ER will conduct all release response, notification and clean-up in accordance with the Section. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-9 4.2.2. Clearing and Grubbing The site is overgrown with kudzu and various smaller trees and brush. ER will utilize a combination of a >10,000 pound tracked skid steer with a brush cat attachment to clear the kudzu and smaller brush from the estimated 1.4 acres required to be cleared for site operations per the RD and as determined during the Site visit. Trees will be removed using a chainsaw with crew members dressed in appropriate PPE and with an excavator w/thumb. As stated, larger trees outside the cap containment footprint will be addressed on a case-by-case basis to determine if removal is required to allow designated tasks to be completed in those areas. At this time, no large trees were identified as needing to remain from the site visit, but confirmation will be done to ensure if any large trees can remain prior to commencing clearing operations. Any trees to remain will be marked with banner guard and reviewed with the crew prior to starting work. The area to be cleared is indicated on the Soil RD Drawing C-101. All wood and vegetative waste material generated from clearing and grubbing operations will be disposed of off-site an approved local disposal facility. Waste materials will be loaded into transport vehicles utilizing an excavator/skid steer as appropriate and shipped for off-site disposal. 4.2.3. Survey Data and Property Boundaries ER has subcontracted with Donaldson, Garrett and Associates, Inc. (DGA) to perform the necessary surveying tasks at the Site. DGA will complete an initial topographical and boundary survey as required to confirm the site footprint. Once initial survey requirements are completed, DGA will be used to identify excavation areas, proposed cap location/footprint, and for installation of stormwater controls and erosion control features. 4.2.4. Utilities Electricity, water, and sanitation facilities will be required during the RA activities: • Temporary electrical power will be installed during site preparation activities for the office trailers. Each office trailer will require 100-ampere (amp), 220 volts (V) alternating current (AC) service. ER has established an account with the local electrical utility with intent to access the on-site power pole and pole transformers. A local electrical subcontractor will install the power to the trailer by installing a temporary power pole drop with service panel and provide an outside service outlet for additional electrical usage support. • Water for the project will be obtained from the Yadkin County Water Department (YCWD) at the water treatment plant. YCWD does not allow the use of hydrant meters to supply water. ER has established an account with YCWD and plans on using a water truck, minimum 2,000gal capacity, to transport water to the site as needed. A temporary storage tank will be staged on-site to support site operations and provide sufficient water during peak usage periods for project tasks, (excavation, stabilization, and dust suppression during dry conditions.) The mobilization and use of a storage tank will eliminate time lost accessing the remote water filling operation each time the truck needs to be refilled at the YCWD plant. • Potable sanitation facilities (portable toilets and hand wash station) will be placed on-site adjacent to the trailers for use by on-site personnel. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-10 4.2.4.1. Utility Locate ER will contact North Carolina one-call 811 services to locate all site utilities and maintain an active dig ticket before drilling and any excavation or intrusive field work. Excavations made with power-driven equipment is not permitted within 3 feet of known Government-owned utilities or subsurface construction. For work immediately adjacent to, or for excavations near, any identified utility or other buried obstruction, hand excavation or “potholing” will be performed by ER crew personnel with hand tools until the obstruction is uncovered or until clearance for the new grade is assured. If any buried utilities are uncovered, ER will address those on a case-by-case basis and provide the necessary precautions to ensure a safe work zone. 4.2.5. Establish Work Zones The Site is an abandoned facility. Coordination with existing on-site operations by others will not be required. Coordination activities with the site owner will be performed by EPA. Survey control points will be established and documented prior to the start of intrusive work. The proposed work limits will be surveyed and staked prior to the start of work, and all critical utilities, wells, and other structures within those proposed work limits or adjacent to proposed access routes should be adequately located and marked so that they are clearly visible to site personnel. Temporary barriers will be erected as needed to protect sensitive areas. Designated areas within work zones will be established to reduce the accidental spread of hazardous substances by workers or equipment from the contaminated areas to the clean areas. ER personnel will confine work activities to the appropriate areas, thereby minimizing the likelihood of accidental exposure; and facilitate the location and evacuation of personnel in case of an emergency. To accomplish this, the site will be divided into as many zones as necessary to ensure minimal employee exposure to hazardous substances. At a minimum, three zones will be identified: • The Exclusion Zone (EZ) • The Contamination Reduction Zone (CRZ), and • the Support Zone (SZ). Movement of personnel and equipment between these zones should be minimized and restricted to specific access control points to prevent cross contamination from contaminated areas to clean areas. The soil excavation areas, cap construction area, ISS, and S/S areas are shown on RD Drawings C-211 to C-311. Site controls will be set up during implementation of the remedial activities. The following materials may be used to barricade construction areas/mark work zones and control traffic when necessary (such as heavy equipment offloading): • Temporary fence. • High visibility tape, rope, or chains. • Signage. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-11 • Traffic cones/barriers; and • A spotter, where appropriate. 4.2.6. Stabilize Construction Entrance A stabilized construction entrance will be installed as per Soil RD Drawing C-401 and C-641. ER will cut the subgrade down to a minimal depth of 6-inches, install filter fabric subbase and place stone. ER will utilize a tracked skid steer to aid with construction of this entrance. ER will erect both, trucks entering and men working signage along this entrance area. The construction entrance will be maintained throughout the life of the project and replenished with stone as needed. 4.2.7. Stabilize Access and Haul Roads Temporary access roads will be required to transport contaminated soil within the project area and import clean fill from off site to backfill previously excavated contaminated areas. Soil RD Drawing C-401 shows the proposed access and haul routes with ER providing acknowledgment or alternate routing in their plan submittals. As specified in Section 31 00 0 0 of the RD Specification The material for aggregate shall meet the requirements for "base course or larger as specified in the North Carolina Department of Transportation (NCDOT) Standard Specifications for Roads and Structures. All existing roads off site shall be maintained in equal to or better than pre-RA condition. Provisions for traffic control when trucks are entering or leaving the Site shall be made in accordance with North Carolina Department of Transportation (NCDOT) requirements. 4.2.8. Erosion Control Measures Stormwater management and erosion control measures are described in the Site Erosion Control Plan, located in Appendix B of this document. ER will use appropriate engineering measures for control of dust, stormwater, erosion, and equipment decontamination runoff as necessary during all excavation, hauling, placement and loading/ unloading operations. Environmental controls shall be in place prior to any intrusive work in contaminated areas. Erosion control measures will consist of a construction entrance, silt fence, transitory soil berms/drain piping and diversion ditches, waddle logs, straw bales, stone check dams and stoned piping outfall protection. These items will be installed with ground personnel, walk behind trencher, excavator and tracked skid steer. ER will repair, replace, and move transitory erosion controls throughout the project as needed. ER will all conduct erosion control checks after each rain event and document any malfunctions and repairs that may be necessary. Engineering controls will be designed to suppress visible dust above limits specified in ER’s HASP and Air Quality Monitoring Plan. The specific requirements for the Air Quality Monitoring Plan are included in Section 01 57 19 of the specifications. ER will be responsible for applying a suppressing agent (clean water or other approved agent) on all work and transportation surfaces, stockpiles, and in the stabilization area in accordance with a preventive schedule contained in the RA Work Plan. ER will perform fugitive dust monitoring during performance of the work, which is outlined in the Site Air Monitoring Plan. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-12 4.2.9. Site Security and Fencing The Site is unsecured and located in a visible area along U.S. Highway 601 and therefore may be susceptible to theft and/or vandalism. ER will be responsible for the security of equipment and materials, providing and installing temporary orange safety fencing and poly jersey barriers around equipment and material storage areas, and utilizing a security service, to prevent theft and vandalism if necessary. 4.2.9.1. Equipment & Material Storage ER will provide a single, lockable Conex box for storage of everyday items, such as hand tools, equipment maintenance items, erosion control items and ancillary items. The Conex box will be located close to the onsite job trailers in the support zone and will remain outside the work zone. The construction related equipment (excavator's, dozer, dump trucks, skid steer, etc.) will remain inside the exclusion zone. 4.2.9.2. Frontage Road and Entrance Gate ER will be responsible for the security of equipment and materials. ER will provide and install temporary plastic safety fencing along the frontage of the site and where appropriate, in addition to utilizing a security service, to prevent theft and vandalism. 4.2.9.3. Site Security Through competitive procurement, ER will has identified a local subcontractor to provide security service during non-working hours at the site. It is anticipated the security company will provide staffing from 1730 to 0700 Monday-Friday and 24hrs [all day] Saturday and Sunday. This schedule could change if the site's scheduled requirements change. Security will be provided with a list of site personnel to contact in case of any issues or circumstances at the site that requires notification. 4.2.10. Equipment Decontamination A temporary decontamination pad will be constructed in designated work areas, or in a central location, prior to beginning the work. Contaminated equipment will be decontaminated by washing with steam or high-pressure water until visible traces of soil are removed. Decontamination water will be collected, stored, analyzed, and treated (if necessary) by ER prior to transport and disposal at an approved facility. The decontamination area will have secondary containment. Equipment traffic patterns in work and non-work areas should be coordinated to minimize the amount of traffic in contaminated areas. Wheel washes should also be used at each exit from the Site to minimize sediment tracking onto roadways. 4.2.11. Waste Management Waste generated during the RA is expected to include unused soil samples or cores, contaminated PPE, and sampling devices. Soil IDW will be placed under the cap (if it has not been constructed yet); remaining IDW will be placed into 55-gallon drums and stored on site for future disposal by ER. The IDW staging location will be determined by ER and approved by the RPM. Drums will be stored on pallets, properly secured, and covered with tarps. 4.3 DEMOLITION ACTIVITIES This section of the RA Work Plan is intended to describe procedures for demolition, removal of demolished materials, disposition of materials specified to be salvaged, coordination with other Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-13 work in progress, disconnection of utility services, and a detailed description of means and methods to be used for each operation, and of the proposed sequence of operations. Before the start of demolition activities, a walk-through of the planned demolition area will be performed to assess and identify any potential for the presence of demolition-related hazardous materials. Lead and asbestos containing material will be properly removed and disposed of based on local, state, and federal guidelines before the building is demolished. This may include additional lead and asbestos sampling to identify all hazardous materials requiring disposal. According to the EPA’s and North Carolina’s regulatory definition, lead-based paint was not identified in the Site building during the RD lead inspection. However, lead-containing paint/materials were identified. Demolition activities are indicated on the demolition drawing (C-111). The building was tested and found to contain asbestos containing material (ACM) and lead based paint (LBP) during previous assessment activities and will be handled accordingly. 4.3.1.1. ACM Work Zone The asbestos inspection report from One Source Environmental dated April 20, 2020, page-1 asbestos results indicated that the following items tested positive for the presence of ACM: a. Window putty on four steel windows, b. Roofing materials on the flat roof portion of the building, c. Grey-black tar placed around the chimney on the flat roof, d. Grey-black tar placed around pipe intrusions through the lower metal roof, and e. Tar located under part of the flat roof. ACM will be properly removed and disposed of based on local, state, and federal guidelines before the building is demolished. As mentioned, this may require additional lead and asbestos characterization sampling to identify all hazardous materials requiring disposal. The ACM work zone will consist primarily of the cinder block office portion of the structure. 4.3.1.2. ACM Work Practices ER will first submit an Asbestos Permit Application and Notification for Demolition Renovation Form 3768 that will be submitted through NCDHHS. This will be submitted prior to abatement of the asbestos from the building prior to demolition, physical demolition of the building, and to notify the state on the TSCA landfill planned for use for demolition wastes and debris generated during demolition. A waste tracking log will be maintained during the off-site T&D of ACM shipped from the site and will be available for review. Additionally, prior to mobilization, disposal procurement will have been completed for the ACM, spent PPE, and construction and demolition (C&D) debris, with award to a CERCLA-approved disposal facility, First Piedmont Corporation Landfill in Ringgold, Virginia. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-14 Vendor-supplied roll-off containers will be used for collecting and shipping ACM removed from the site building. The roll-off box will be double-lined with (6) mil polyethylene and each layer will be of sufficient width to overlap the container. This additional width allows the top polyethylene cover to be properly secured and Department of Transportation (DOT) shipping labels affixed to the top polyethylene cover. Once the waste is secured, the box bows will be re-installed, and the roll-top tarp deployed and secured to the box. The roll-off box will be labeled with the generator name and address, approved profile number and date of waste accumulation. The container will be labeled per 29 CFR 1910.1001(j)4(i), with “Danger” and “Possible Cancer and Lung Disease Hazard” prior to use. To the extent possible, office furnishings, debris and ancillary items inside the office space will be removed to the warehouse area. Personnel will install a decontamination station for controlled entry into, and exit from, the building interior, which will be designated as the EZ. This will also include placement of asbestos caution tape around the building with OSHA required warning signs posted and in place prior to beginning work. All personnel entering the EZ, including workers, supervisory personnel, or approved visitors, will be required to comply with EPA Level C personal protection equipment (PPE) protocols, which includes use of impervious outer coveralls, disposable boot covers, double gloves, and a full-face APR, using HEPA filtered P100 cartridges. An entry log will be maintained for all personnel and approved visitors entering the EZ, with all personnel properly trained for entry into the building per CFR 1926.1101. ACM abatement will involve pre-wetting all surfaces with an approved wetting agent and always maintaining work surfaces and the waste being removed in a damp condition with hand actuated pump sprayers. ER will lay down 2-layers of 6-mil poly under each abatement area to collect any potential ACM items that may fall. This poly sheeting will be collected and bagged as each work area is completed. A scissor lift may be utilized to gain access to the office roof and warehouse parapet. The built-up roofing will have to be saw cut and will have a HEPA vacuum attachment for collection of airborne dust that may be generated. Flashing will be removed manually by scraping and prying to the extent possible. The windows will first be HEPA vacuumed and then unfastened from their frames and removed in their entirety. Waste collected will be placed inside 6-mil polyethylene drum liners and double-bagged or double wrapped in 6-mil poly sheeting. A variety of miscellaneous building materials, such as roofing felt, flashing, brick, roofing tar with metal sheeting and window glazing will be collected, properly bagged, and removed prior to demolition. 4.3.2. Lead Stabilization Activities The lead-based paint inspection report from One Source Environmental dated April 20, 2020 results indicated that the following items tested positive for the presence of lead-based paint: a. Ceramic tile glazing in the building’s bathroom b. Exterior door casing and metal awning support (painted surfaces) c. Exterior sheet metal wall- side “B” (silver paint areas) Lead containing materials will be properly stabilized and disposed of based on local, state, and federal guidelines before the building is demolished. Lead-containing paint was found on several Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-15 interior and exterior painted surfaces throughout the building and in the glazed ceramic tiles in the bathroom. Only the three (3) identified items (a, b, c) above will be resampled for TCLP (Toxicity Characteristic Leaching Procedure) analysis post-abatement for determining the final disposition of waste into a landfill. If these items pass the TCLP analysis, they will go out as C&D waste and not require any special disposal as hazardous waste. At a minimum, the lead related items work area will be wetted with a lead Lockdown agent before the demolition process. If the TCLP analysis fails, then ER will assume these items will need to be handled as a special waste and will be removed as part of a selective demolition process prior to structural demolition. ER will establish and demarcate a work zone around these areas prior to abatement. ER will utilize HEPA filtered vacuuming equipment with a UL 586 filter system capable of collecting and retaining lead contaminated particulates. A high efficiency particulate filter demonstrates at least 99.97 percent efficiency with 0.3 micron or larger size particles. A layer of 6-mil poly sheeting will be placed on the flooring/ground beneath each elevated work area. These pieces of poly sheeting will be removed after completing each work area. All poly, cleaning items, rags and PPE will be bagged for disposal. The surfaces will be vacuumed to removal any lead dust, the surface wet wiped and the surface wet wiped again. After the TCLP results, ER will then remove any remaining lead impacted items in their entirety and put them into a separate roll off container. The roll-off box will be double-lined with (6) mil polyethylene and each layer will be of sufficient width to overlap the container. This additional width allows the top polyethylene cover to be properly secured and DOT shipping labels affixed to the top polyethylene cover. Once the waste is secured, the box bows will be re-installed, and the roll-top tarp deployed and secured to the box for transportation and disposal to a properly permitted and CERCLA-approved Subtitle “C’ landfill. ER may elect to package the waste into small containers if the quantities warrant it. 4.3.3. Structure and Site Demolition Once all pre-demolition abatement operations are complete, and the building has been prepared, demolition operations will commence. Any light ballasts, electrical wiring, conduit, or instrumentation control panels that remain inside the building will be removed prior to demolition. The structure will be thoroughly wet, and water fog will be used during demolition of the building, foundation, or other physical features. The building will be carefully demolished using a hydraulic excavator and thumb, working downwind away from the SZ. C&D debris generated will be kept in a damp condition prior to loading into demolition roll-off boxes and transported off-site for disposal. The building will be demolished in a top-down approach. The metal siding and roofing to the extent possible will be pulled from the wooden rafters and wall sub-slates. There is approximately 1400 linear feet of metal fencing that surrounds the closed surface impoundment, closed land farm area and runs across the property that will be removed as per demolition drawing C-111. ER will segregate the metals from the other C&D related items and put them into respective piles. These piles will be loaded into trucks/trailers or roll-offs for disposal and recycling. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-16 Additionally, there may be a septic tank on the property. If ER can locate this septic tank, ER will have the septic tank pumped out with a vacuum truck and then remove the tank. The razed concrete tank and septic lines will be put in a roll off for disposal at the landfill. Upon completion of razing activities, the concrete slab at grade will be left and handled separately, see 4.3.3.1 below for a more detailed description of concrete demolition activities. ER will utilize a hydraulic excavator w/thumb, skid steer and a water truck w/water hoses during the performance of the structural razing. If present, the site transformer will be uncoupled from the building prior to demolition and carefully staged inside a secure containment area, pending disposal. The transformer is assumed to be containing > 500 ppm PCB oil and is regulated under TSCA as a PCB transformer. This assumption is based on the age of the building, likely age of the transformer, and when the business was operational. The transformer and contents will be transported off-site for disposal with Emerald Transformer PM, LLC, (Emerald) in Twinsburg, Ohio, a Region 5 CERCLA approved TSCA facility. Emerald Transformer will supply a flatbed trailer with secondary containment to set the transformer into for transportation to their facility. ER will load the transformer with a forked skid steer or possibly an off-road forklift depending on the transformer's weight. Note: the transformer was not found onsite at the time of RA mobilization and is believed to have been stolen. 4.3.3.1. Concrete Foundation Removal The concrete slab structure will be thoroughly wetted, and a water fog will be used during demolition of the slab and foundation features, to prevent the spread of dust and debris. The concrete will be carefully demolished using a hydraulic excavator w/concrete hammer/breaker for rendering and removal of foundations or other enforced portions of the structure. A second excavator will be utilized to handle and pull up broken concrete, with any voids created from the footers being backfilled with onsite stockpiled soils The broken concrete will be temporarily staged in piles until the building footprint has been razed. If the septic tank can be located when removing the concrete, it will also be loaded out with the other concrete. Concrete debris generated will be kept in a damp condition prior to loading into dump trucks/trailers for transport off-site for recycling. ER will utilize a hydraulic excavator w/thumb and a concrete breaker, skid steer and a water truck w/water hoses during the performance of the concrete razing. 4.3.4. Well Abandonment Monitoring and/or recovery wells that are abandoned will be subject to the reporting requirements as found in Title 15A, Chapter 2C, Section 0113 of the North Carolina Administrative Code. This requires all abandonment procedures to be completed by a North Carolina certified well contractor and a record of abandonment, Form GW-30, to be submitted to the state within thirty (30) days of the specific well being abandoned. For wells greater than twenty (20’) feet in depth, and for wells other than water supply wells, including temporary wells, monitoring wells, or test borings, the following abandonment procedures will be followed: • If the well penetrates the water table, the well must be abandoned by filling with a bentonite or cement-type grout. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-17 • The bentonite or cement grout will extend five (5) feet below the bottom of the well casing or ten (10) feet or greater below the top of the consolidated rock formation, if applicable • If a well casing is not removed, the bentonite or cement-type grout will extend from the top of the casing string to the surface. • If the casing string is removed, bentonite or cement fill material will be installed to the surface. The following wells in the remediation area will be abandoned: • MW-5 • MW-21 • MW-24 • MW-25 • MW-26, • MW-27, • MW-28, • MW-30, • MW-31, • MW-32, • MW-33, • MW-45, • MW-48, • MW-49, • MW-50, • MW-52, • MW-53. and • The onsite supply well (wells slated for abandonment are shown on Drawing C-111 of the Soil RD). Well abandonment will be completed by Geologic Exploration, a licensed North Carolina Driller. Wells will be abandoned in accordance with EPA and NCDEQ requirements. Wells in shallow excavation-only (not stabilized) areas will be preserved. Soil cuttings and rinse/development water generated from well abandonment operations will be collected, containerized, and consolidated into the containment cell once constructed. Four saprolite monitoring wells will be specifically retained for future monitoring of the containment cell: • MW-22, • MW-23, • MW-55 and • MW-56. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-18 4.4 TRANSPORTATION AND DISPOSAL (T&D) OPERATIONS ER has solicited and awarded subcontracts for the T&D of waste materials identified at the site to CERLCA approved TSDFs. ER’s T&D Coordinator has coordinated with the selected TSDFs to ensure all certifications and regulatory requirements have been met. The table below identifies the waste stream and selected TSDF with confirmation from the EPA Regional Offsite CERCLA Contact verifying acceptability of the TSDF. The subsections below identify known waste streams at the site requiring off-site T&D and the approach to each. 4.4.1. Recycling ER has provided alternative disposal avenues for three waste streams from the site; • Vegetation-Trees / Brush • Concrete • Scrap Metal All recyclable materials will be loaded with the excavator/skid steer as appropriate into staged transport containers for off-site shipment to locally permitted recycling facilities to be recycled / reused. Vegetation will be ground and used as mulch, concrete will be crushed and used as road aggregate, and scrap metal will be smelted. Concrete and scrap will be decontaminated as appropriate with dry methods and/or with high pressure wash as necessary utilizing the equipment decontamnation station. Decontamination water will be captured and reused as dust suppression with EPA approval in contaminated soil excavation or on-site stabilization operations. Waste Stream TSDF EPA ROCC Vegetation -Trees / Brush Andrews Farm Landfill -Recycling Not Applicable -recycling C&D -Building Debris AWMSI to WM Great Oak Landfill Raj Aiyar -R4 RROC C&D -Concrete SOAR- Smart Onsite Aggregate Recycling Not Applicable -recycling ACM First Piedmont Corp Landfill Raj Aiyar -R4 RROC Transformer Emerald Transformer William Damico -R5 RROC Lead AWMSI to WM Emelle Raj Aiyar -R4 RROC Scrap Metal Local Recycler Not Applicable -recycling Trash (Office/Misc.) AWMSI to WM Great Oak Landfill Raj Aiyar -R4 RROC Soil Borings-Phase 2 Injection TBD-contingent on Phase 2 Injection TBD Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-19 4.4.2. C&D Building Debris / Trash All building demolition debris will be loaded with the excavator/skid steer as appropriate into staged tri-axle dump trucks for off-site shipment to locally permitted landfill for final disposal. All loads will be covered prior to transport off-site to the CERCLA approved TSDF (Transportation, Storage, and Disposal Facility). A roll off box will be staged onsite for the collection of waste items associated with the injection work, soil stabilization, damaged erosion control items, and other trash generated during the project. The roll off box will be emptied as needed throughout the life of the project. 4.4.3. Transformer The Transformer has been profiled into an approved TSDF for final disposal. Transformer will be packaged meeting all DOT and TSDF requirements. The Transformer will be secured to a pallet and staged for T&D. The palletized Transformer will be loaded on a flatbed semi-trailer equipped with a metal spill containment "tray" for off-site shipment to an approved facility. The transformer will be properly labeled “Caution contains PCBs” per 40 CFR 761 and the transport placarded per 49 CFR § 172.504. 4.4.4. ACM -Asbestos Contaminated Material All identified ACM material will be removed and placed into a staged double lined roll off with appropriate signage and labeling. The roll off will be shipped off-site to a TSCA approved facility for final disposal. ACM abatement supervisor will have current North Carolina asbestos site supervisor accreditation for ACM abatement. All ACM abatement personnel will be trained in accordance with North Carolina asbestos abatement regulations. 4.4.5. Lead If analysis indicates lead above regulatory limits, ER will package the lead contaminated materials into lined cubic yard boxes and staged for T&D. Off-site T&D will be completed to a CERCLA approved hazardous waste approved TSDF via van trailer. 4.4.6. Injection Soil Borings [If Needed] The initial mobilization for ISEB injections will be conducted exclusively with DPT and for this reason will not require disposal of any remediation waste, other than trash. During the second ISEB injection mobilization, injection points within the stabilization area are expected to require the use of rotasonic drilling to advance the injection tooling. Cuttings from rotasonic drilling will be drummed and sampled for waste characteristics. ER will procure T&D services for this waste stream. The drummed drill cuttings will then be profiled and disposed of at an approved CERCLA disposal facility. 4.4.7. Manifest Tracking & CERLCA Reporting As stated, ER’s T&D Coordinator will arrange the T&D of the waste materials in coordination with the ER Response Manage (RM). Selected TSDFs will provide all necessary manifest documentation including applicable land ban forms as required. All CERLCA verifications have been received and local recycling facilities verified in compliance with their oversight regulatory agency. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-20 4.5 GROUNDWATER INJECTION ACTIVITIES -PHASE 1 Drilling subcontractor, Geologic Exploration of Statesville, NC, will mobilize to the HCC site and conduct mixing and injection of ISEB amendments to treat the approximately 2,640,000 gallons of contaminated groundwater identified in the RI/FS and Groundwater RD. ER will direct and oversee the groundwater injection activities. The ISEB amendments will be injected into the subsurface to increase the population and health of indigenous microorganisms capable of metabolizing contaminants and thereby treating contaminated groundwater. ISEB will be implemented in both the saprolite and PWR groundwater. During injections, field observations with regard to injection volumes, required injection pressure, and daylighting to ensure that the 6-foot radius-of-influence (ROI) presented in the groundwater RD is being met. In the event that the 6-foot ROI isn’t achievable based upon field data, HGL, EPA, and the NCDEQ will be consulted to update the injection approach. 4.5.1. Injection Procedures, Locations, and Depths ER has subcontracted with drilling subcontractor Geologic Exploration to provide personnel and equipment to conduct direct push drilling and injection of ISEB amendments into the subsurface to increase the population and health of indigenous microorganisms capable of metabolizing contaminants and thereby treating contaminated groundwater. ISEB will be implemented in both the saprolite and PWR groundwater. It is anticipated that two GeoProbe 7822 (or equivalent) will work concurrently with additional personnel performing injectant mixing. Injectant will be mixed in two (2) 350-gallon 45° cone bottom poly tanks with Generac 2” chemical rates centrifugal pumps for circulation of the slurry. The slurry will be injected using 1” diaphragm pumps. The injection steps will be as follows: a. Fill a 350-gallon tank with the correct volume of water. b. Begin circulation pump. c. Add injectant material to tank. d. Check ratio of water to injection material for correct percentages e. While material is being mixed, Driller will advance injection tooling to desired depth. Once all hoses are connected, rods will be pulled up to the first interval depth. f. Once the product is mixed thoroughly, driller will proceed to inject material via manifold at the specified flow rate. g. When target volume is achieved, rods will be extracted to the next interval and pumping will continue. h. A spotter will be used when injecting near the creek to insure that any daylighting with the potential to impact surface water will be quickly mitigated. During the Holcomb Creosote Groundwater Remedial Design (RD) calcium peroxide slurry was successfully injected into the saprolite by DPT. Calcium peroxide slurry injections into the PWR were not evaluated. A difficulty with the RA ISEB implementation at the HCC Site will be injection into the PWR. Calcium peroxide slurries can only be injected via open boreholes; injection wells are not viable for delivery of the slurry. In an injection well, slurry solids would Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-21 bridge the well screen and undistributed slurry solids would settle and fill the well. However, DPT borings have been successfully advanced to the upper layers of the PWR at the Site. Primary Remedial Action ISEB treatment areas and locations are presented on Sheet C-02 of the Groundwater RD. This drawing labels each injection point for ease of reference. The approximate ISEB injection intervals are included on Table 4-1 of this document. These intervals are estimates from the RD, based on expected PWR depths and water table depths. Actual injection intervals will be determined in the field based on DPT refusal depths encountered and water levels measured in nearby monitoring wells, in accordance with the procedures discussed below. The ISS intervals are also considered, and ISS depth intervals are not included in ISEB in the ISEB treatment intervals. Injection points were not called for in the RD between MW43 and the fence line due to the steep slope in this area. In the former operations area, the saprolite and PWR ISEB treatment areas are approximately the same and cover an area of 8,060 square ft. Within and near the closed surface impoundment, the PWR high concentration groundwater plume is larger than the one in the saprolite; therefore, the PWR treatment area is larger than the saprolite treatment area. The proposed saprolite treatment area for the closed impoundment plume is 8,060 square ft. The PWR treatment area includes the 8,060-square-foot area for the saprolite and an additional 9,360 square ft to the southeast, for a total treatment area of 17,420 square ft. In areas where both the saprolite and PWR are treated by DPT injection, the vertical extent of the ISEB treatment will be from the water table to the depth of DPT refusal. This interval is expected to treat the entire saturated thickness of the saprolite and up to approximately the upper 5 ft of the PWR. At each location, DPT rods fitted with an expendable steel point will be driven to refusal. The expendable point will be ejected, and injection will proceed from the bottom up in 2 ft intervals to the water table, or until uncontrolled daylighting or water table mounding occurs. The depth to the water table will be determined by measuring water levels in nearby monitoring wells. Depth to water varies significantly at the Site due to changes in ground surface elevation. In areas with shallow groundwater, injections may need to be stopped deeper than planned in cases of excessive mounding and daylighting. If excessive daylighting or water table mounding occurs at multiple injection points within the same area, injection equipment will be moved to another area of the Site to allow subsidence of the water table before returning to finish the injection. Since a safety factor of 1.5 was used in the dosing calculations, the minimum amount of PermeOx® Ultra required for each injection point is 2/3 of the total included in the specifications. DPT refusal depths are expected to vary due to Site topography. Approximate injection intervals for combined saprolite and PWR locations are as follows: • In the former operations area, DPT refusal depths encountered within the ISEB treatment area ranged from 16 ft Bgs to the east to 32 ft Bgs to the west near the Site buildings. Depth to groundwater varies seasonally, but ranges from near ground surface adjacent to the unnamed tributary to up to approximately 11 ft Bgs near the Site buildings. As presented in Table 4-1, an average treatment interval thickness of approximately 20 ft is expected. • In the closed impoundment area, DPT refusal depths encountered within the ISEB treatment area ranged from 22 to 30 ft Bgs, and the depth to water ranges from Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-22 approximately 1 to 4 ft Bgs. As presented in Table 4-1, an average treatment interval thickness of about 26 ft is expected. • The southeast portion of the former operations treatment area, downgradient of saprolite monitoring well MW 27, includes only saprolite treatment. As presented in Table 4-1, the treatment interval in this area is from approximately 5 to 17 ft Bgs. Bottom-up injection procedures will be followed in this area as described for the combined saprolite/PWR locations, with the exception that the DPT rods will be advanced to the target treatment depth instead of refusal. • The northwest portion of the former operations treatment area toward PWR monitoring well MW-50 includes only PWR treatment. Based on Table 4-1, I treatment interval in this area is anticipated to be between approximately 21 and 26 ft Bgs. At the PWR only injection locations, the DPT rods will be advanced to refusal, and injection will occur over two 2-ft intervals above the refusal depth. • The southeast portion of the closed impoundment treatment area includes only PWR treatment. As presented in Table 4-1, the treatment interval near MW-44 is anticipated to be between approximately 33 and 38 ft Bgs. The locations downslope of MW-44 to the northeast, along the unnamed tributary, and those closer to the closed impoundment will likely encounter refusal at shallower depths. At the PWR-only injection locations, the DPT rods will be advanced to refusal, and injection will occur over two 2-ft intervals above the refusal depth. 4.5.2. Materials for Injections The material that will be injected to promote aerobic bioremediation is PermeOx® Ultra, manufactured by Evonik, as the ISEB injection amendment. PermeOx® Ultra contains 75% by weight calcium peroxide and 25% by weight calcium hydroxide and reacts with water to generate 18% by weight oxygen over a period of up to 1 year. A total quantity of 51,000 lbs of PermeOx® Ultra will be required for the primary ISEB injection treatment which ER will procure from Evonik corporation. The injection material will be delivered to the HCC site in 1-ton supersacks. The drilling subcontractor will mix the injectant onsite, in powder form, with potable water to create a slurry for subsurface injection. 4.5.3. Injection Dosage To achieve a 10% pore volume displacement, the PermeOx® Ultra will be injected with approximately 27 gallons of dilution water per foot of treatment interval in both ISEB treatment areas. This will result in PermeOx® Ultra injection concentrations of 7.0% by weight for the former operations area and 8.5% by weight for the closed impoundment area. The PWR-only injections at the former operations area and down gradient of the closed impoundment area will be implemented with 7.0% by weight PermeOx® Ultra solution at 27 gallons per foot due to the lower COC concentrations present in these areas. The total PermeOx® Ultra saprolite demand from the dosing calculations is 36,324 lbs. The saprolite depth intervals used for the dosing calculations were revised based on the saprolite intervals in Table 4-1 of the RD, yielding a revised total PermeOx® Ultra saprolite demand of 37,850 lbs. Approximately 127 ft of the saprolite injection intervals will instead be treated by ISS, reducing the total PermeOx® Ultra saprolite demand to 35,397 lbs. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-23 The total PermeOx® Ultra needed for the initial, primary injection is 51,000 lbs., which includes approximately 22,100 lbs. for the operations area and PWR only locations and 28,900 lbs. for the closed impoundment locations. Water for mixing and decontamination will not be available onsite. The subcontractor will be required to carry water from the Yadkinville County water treatment plant located approximately 5 miles south of the site on US-601. Injection volumes will be recorded for each injection location by depth and dosage. Occurrence of daylighting will also be recorded. 4.5.4. Surveying Prior to commencing injection activities, injection locations will be staked in the field by a crew from DGA, the subcontracted North Carolina licensed surveyor. The locations will be based on the grid layout depicted in figure C-02 of the Groundwater RD. Any deviations from the layout presented in the figure will be presented to HGL and approved by EPA. 4.6 SOIL EXCAVATION AND ON-SITE CONSOLIDATION Concurrent with well abandonment operations, a pre-excavation survey will be completed to establish excavation, staging, and containment cell locations, within the Area of Contamination (AOC). This survey will coincide with marking and clearing utilities. Marked utilities will be “pot-holed” to help determine both depth, direction, and existing condition of the utility prior to conducting excavations. This allows for utilities that are in areas of concern to be protected prior to subsequent operations in the AOC. Once surveys are complete, with all site areas identified and marked, site access and haul roads will be constructed and/or existing roads improved. The containment cell will be staked, and the area intended for use cleared of sharp stones, excess vegetation, and foreign materials. Excavations to remove clean overburden will begin with the material that is removed staged to a designated stockpile area for subsequent reuse. The material to be used as general fill will be loosely sorted once excavated to remove stones, rock, or other debris prior to use. At this time any depressions from the building demolition footer removals will be backfilled to grade. Once the clean fill material is excavated and staged for subsequent re-use, excavations of certain contaminated soil areas lying outside the proposed locations of the containment cell, the existing closed surface impoundment, and land treatment unit will begin. The excavated soil, and potential over excavation material, will be staged for placement in the containment cell. Once all surveying and/or sampling is completed, excavation areas outside the containment cell, inside the AOC, will be backfilled, compacted, and lightly graded. A combination of hydraulic excavator and tracked dump truck will be utilized for this process. 4.6.1. Soil Excavation Delineation ER will layout proposed excavation areas with a combination of wooden survey stakes and spray paint to aid in a visual delineation of the proposed excavation areas. An as-excavated survey will be conducted to record depths and elevations from the host grids once excavations are completed. The proposed excavation areas are presented in Drawing c-200 of the Soil RD. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-24 4.6.2. Temporary Soil Stockpile Construction Designated clean soil will be stockpiled in areas of uncontaminated material (a clean soil stockpile area is depicted on Soil RD Drawings C-201, C-202, C-301, and C-601). Contaminated soil will be temporarily stockpiled on an existing contaminated area wherever possible or upon a liner. The final location of the temporary soil stockpile staging areas will be determined by ER, as approved by EPA. Stockpiles shall be constructed in accordance with Section 02 61 13, Subsection 3.6.1 of the soil RD. 4.6.3. Excavation -Clean Overburden Excavations to remove clean overburden will begin with the material that is removed staged to a designated stockpile area for subsequent reuse. Excavation will start at the furthest area and work its way towards the designated stockpile area. The material to be used as general fill will be loosely sorted once excavated to remove stones, rock, or other debris prior to use. A combination of hydraulic excavator and tracked dump truck to move the soils to the staging area will be utilized. A tracked skid steer will be used to shape the stockpile footprint. Clean soil area excavations and depths are presented in Drawing C-201 of the Soil RD. 4.6.4. Excavation -Contaminated Soil Once the clean fill material is excavated and staged for subsequent re-use, excavations of certain contaminated soil areas lying outside the proposed locations of the containment cell, the existing closed surface impoundment, and land treatment unit will begin. The excavated soil, and potential over excavation material, will be staged for placement in the containment cell. An as-excavated survey will be conducted to record depths and elevations from the host grids once excavations are completed. Once all surveying and/or sampling is completed, excavation areas outside the containment cell, inside the AOC, will be backfilled, compacted, and lightly graded. 4.6.5. Consolidation ER will consolidate excavated soils into the containment cell by utilization of a hydraulic excavator to remove in-situ soils and cast them either directly into the cell footprint if proximity allows or loading onto a tracked dump truck and delivering spoils to the cell area. Soils placed inside the cell footprint will be rough graded with a dozer to a predetermined depth of 1 ft or less. Spoils placed inside the containment cell will be placed on the south end and worked north to the high end of the cell footprint. ER will consolidate overburden soils to the designated stockpile area in much the same way. An excavator will direct load spoils into a tracked dump truck that will deliver it to the staging area. Once dumped it will be shaped and maintained by a tracked skid steer. 4.6.5.1. Compaction Testing ER will place backfill in successive horizontal layers of loose material not more than 8 inches in depth and compact to at least 90 percent laboratory maximum density. Backfill material will be within the range of +/- 2 percent of optimum moisture content at the time of compaction. ER will subcontract a geotechnical subcontractor to conduct compaction testing to verify that 90% compaction has been met. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-25 Finish compaction will be achieved by sheepsfoot rollers, or other approved equipment. Compaction will be verified by either test procedure ASTM D698 (Proctor) or ASTM D6938 (Nuclear Density). 4.6.6. As-Excavated Survey An as-excavated topographic survey will be conducted by DGA to record depths and elevations from the excavated areas once excavations are completed and verify that the extent of excavation outlined in the Soil RD has been met. 4.6.7. Rough Grade Backfill and Compaction Once all surveying and/or sampling is completed, excavation areas outside the containment cell, inside the AOC, will be backfilled with clean material, compacted, and lightly graded. 4.6.7.1. Excavated Areas After excavation limits have been achieved, and there are no indications of remaining soil impacts (based on field observations) and/or confirmatory sampling has demonstrated that soil cleanup levels have been achieved, the excavated areas will be backfilled with clean granular fill and graded per Soil RD Drawing C-311. Satisfactory backfill will meet the parameters described in soil RD specification Section 31 00 00 Subsections 1.2.1 and 1.2.2. ER will provide a clean testing certificate from the fill supplier. Backfill activities will include: • Backfill will meet location and requirements shown on plans and specifications. • Backfill will be compacted to 90 percent compaction in 12-inch lifts. In accordance with Section 31 00 00 Subsection 3.5.1 of the soil RD, ER will scarify the surface to a depth of 6 inches before the fill is started and plow, step, bench, or break-up sloped surfaces steeper than 1 vertical to 4 horizontal so that the fill material will bond with the existing material. 4.6.7.1.1. Finish Grade Within two feet of ground surface, stockpiled clean material from the site and additional offsite borrow (if necessary) will be emplaced to bring the excavated areas to finish grade. Additional backfill activities will include: • Erosion protection rock will be placed in drainage ditches to restore the flow line elevation of the ditches to match the revised invert elevations of culverts as shown in the plans. • The final backfill and surface elevation grading will be verified by post-construction surveys. 4.6.7.2. Cap Area The top of the cap system will be sloped to drain to the perimeter of the containment cell. The drainage system will consist of a continuous geonet layer to promote drainage off the 40-mil HDPE top geomembrane liner. The geonet will include a bonded geotextile filter to separate the drainage net from the overlying soil. The geonet will be extended past the limits of the cap system to terminate in rip rap at the toe of the slope (see detail Drawing C-601). The rip rap will protect the Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-26 toe of the cover soil and the terminated end of the drainage net. The discharge from the geonet system will be collected at the perimeter of the containment cell and directed to natural drainage. The soil cover will consist of a total of 24-inches of clean fill obtained from approved off s sources. Fill sources may be blended to achieve an optimum composition. The first 18-inch-thick layer of protective soil will be compacted over the geonet that overlies the composite liner system. The top of the soil cover will be sloped a minimum of 1 percent to drain rainwater off the capped area. The edges of the cell will be sloped at maximum of 4:1 or 25 percent. A 6-inch-thick topsoil layer will then be placed on the ground surface and vegetated to complete the 24-inch total thickness. The soil cover is designed to prevent erosion on the cap and assumes no future use for development (for example, building foundations or major roads). ER will identify the source of the topsoil to be used as the soil cover. A layer of construction fencing, or other brightly colored material, should be placed 6 inches above the drainage layer to visually alert anyone disturbing the soil above the capping system. ER will sample all potential source material for priority pollutants to determine that there is no contamination within the topsoil fill material. 4.6.7.2.1. As-built Survey Donaldson, Garrett and Associates, the Subcontracted NC land surveyor, will be tasked to produce a post-construction topographic survey to verify the final backfill and surface elevation grading of the containment area. The as-built survey measurements will include a listing of all horizontal coordinates and vertical elevations for each point surveyed and a listing of the horizontal coordinates (recorded in feet, North Carolina State Plane Coordinate System, NAD 1983) and vertical elevations (recorded in feet, National Geodetic Vertical Datum 1988) for the benchmark shall be surveyed such that: All vertical elevations shall be tied to one established site benchmark, to the nearest one-hundredth of a foot (+ 0.01 feet). All control information shall be based on the surveys conducted on the ground. The survey will be of third order accuracy or better. All horizontal coordinates including one site benchmark shall be tied to the North Carolina State Plane coordinate system (NAD 1983) and recorded to the nearest one-hundredth of a foot (+ 0.01 feet). The survey shall be of third order accuracy or better. 4.6.8. Restoration Restoration activities will include seeding and planting vegetation as specified in the Soil RD. This may include restoration of the wetlands and tributary if excavation is necessary in those areas. Additionally, areas of excavation will be re-vegetated to control erosion. Fencing around both the land farm cap and closed impoundment will be removed and reinstalled as necessary. 4.6.8.1. Wetlands and Tributary Restoration If determined to be necessary, the wetland and on-site tributary bed area will be addressed, excavated, and restored once all excavations outside the containment cell area, inside the AOC, are complete. Any spoil accumulations from the wetland and/or tributary bank and bed areas will be further consolidated with the contaminated soils from the AOC. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-27 4.6.8.2. Excavated Areas Excavated areas will be seeded with grass and native vegetation. ER will coordinate with the North Carolina Office of Erosion and Sediment Control and the Yadkin Soil and Water Conservation District Office to determine appropriate seed types, mixture, and purity requirements for temporary and permanent seeding. Seed will be selected to maximize native species and applied by ER using a broadcast spreader, or equivalent. 4.7 NAPL-IMPACTED SOIL STABILIZATION The following subsections will detail ER’s approach to the soil stabilization of the NAPL impacted soil at the site following RD guidelines. 4.7.1. Mix Design Treatment of the contaminated soils will be conducted using a stabilization recipe of 12% water and 8% Portland cement following RD specifications. This mix design will be evaluated for effectiveness and adjusted as necessary based on the current characteristic parameters of the specific grids being stabilized, and in combination with the results of bench scale tests conducted for quality control (QC) purposes. Any field adjustments will be approved by the EPA TOCOR prior to implementation. 4.7.2. Soil Stabilization Process ER will utilize the excavator to mix the impacted soils based on the volume of soils converted to an equivalent weight quantity and the calculated amount of Portland cement added incrementally to the mixing process to treat the volume of soil to the required soil to cement ratio. Portland cement will be added via Super Sacs to measure the appropriate quantity of Portland cement needed for the calculated weight of the treatment area. Water will be added to activate the Portland cement within the soil matrix, with the excavator bucket used to mix the components together until a homogeneous mix is achieved. Duration of the mixing will be in direct correlation to the volume of soil to be treated and the visual inspection of the mixed material to ensure a thorough mix. 4.7.3. NAPL Soil Inside Containment Cell Stabilization of NAPL contaminated soil areas will begin in areas-C & D identified inside the proposed containment cell footprint. Non-NAPL soils will be removed and stockpiled in the south end of the cell footprint for placement after the stabilization of NAPL soils. NAPL soils inside the cell will be treated in situ or in the constructed stabilization pit following RD specifications. For the NAPL soils found below the water table, each excavation will be visually inspected for water intrusion as excavation commences and to remove as much soil as possible in these areas below the water table for treatment in the stabilization pit. The excavation goal would be to remove all the NAPL soils but the bottom 3-5ft in these in situ areas. This interval will be stabilized in place using the stabilization process as identified in 4.7.2 based on the known location and calculated weight of the soil to be treated. Treating the bottom 3-5ft in this manner will allow thorough mixing of this material. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-28 However, treating in situ at a thickness of greater than 5ft will be problematic due to the inability to obtain a homogeneous mixture of a thicker, taller column of NAPL contaminated materials. As stated, ER will monitor conditions below the water table to implement the best approach to thoroughly treat the material according to site specifications. ER will coordinate any deviations with the EPA on-site TOCOR prior to any changes being made. ISS and S/S areas and depths are presented in soil RD Drawing C-301. 4.7.4. NAPL Soil Outside Containment Cell Stabilization of NAPL contaminated soil areas outside the containment cell will be in areas-A, B, E, F, & G. Non-NAPL soils will be removed and stockpiled in the south end of the cell footprint for placement after the stabilization of NAPL soils. NAPL soil outside the cell will be treated in- situ or in the constructed stabilization pit in the containment cell. For the NAPL soils below the water table, excavations will be visually inspected for any water intrusions as the excavation commences in these areas and remove as much soil as possible below the water table for treatment in the stabilization pit. The goal would be to remove all the NAPL but the bottom 3-5ft of the in-situ areas. NAPL soils treated in the stabilization pit may be returned to the appropriate excavation area or added to stabilized material within the containment cell, if appropriate. The materials in each stabilization area which is not excavated to the stabilization pit will be stabilized in place using the stabilization process as identified in 4.7.2, based on the known locations and calculated weights of the soil to be treated in those areas. As stated in 4.7.3, ER will follow the same guideline for treating in situ at a thickness greater than 5ft. ISS and S/S areas and depths are presented in soil RD Drawing C-301. 4.7.5. Solidification QC Testing Quality control samples for laboratory testing of UCS will be performed on mixed and cured samples at a frequency of 2 samples per mixing zone. In total, (12) QC samples will be collected by ER and analyzed for unconfined compressive strength (UCS) and permeability by HGL. For each sampling event, ER will prepare the minimum number of replicate sample molds for UCS testing at 7, 14, and 28 days, and preserve samples for permeability testing at 14 and 28 days. Quality control samples for laboratory testing of UCS will be performed on mixed and cured samples at a frequency of 2 samples per in situ solidification mixing zones (6 zones: Area A; Area B; Areas C & D; Area E; Areas F & G; and the stabilization pit), for a total of 12 samples for the total volume of soils to be treated with S/S of 1,678 bcy (approximately one sample per every 140 bcy). Additional quality control samples will be collected and tested in the field by ER daily during solidification operations to ensure other field parameters are consistent between cells, such as slump, viscosity, and density. 4.8 CONSTRUCTION OF ENGINEERED CAP Once grid excavations, transport of excavated spoils from areas in AOC outside the containment cell location into the containment cell, and stabilization of NAPL contaminated soils inside the Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-29 containment cell have been completed, construction of the consolidation cell cap will begin. This would occur once the as-built survey is complete and no further preparation work for the cell’s base location is required prior to construction. The bottom of the containment cap should be well graded and be smooth and free of any remaining rock or debris to prevent punctures to the liner once installed. After completion of ISS and containment cell construction, ER will re-install selected monitoring wells abandoned during the soil RA. Abandoned monitoring wells MW-25, MW-26, MW-27, MW-28, MW-48, and MW-49 will be replaced. Replacement well MW-48 will be moved approximately 25 feet to the south to be out of the ISS area. Replacement monitoring wells within the footprint of the containment cell (MW-25, MW-26, and MW-48) will be installed after the soil is placed in the containment area and graded, but before the liner is installed. These wells will have boots that will be sealed to the containment cell liner. 4.8.1. Liner System Installation ER will contract a specialty subcontractor to install the engineered cap and liner system. The cap will be constructed using the following materials, with material seams welded and pressure-tested: • An initial layer of geosynthetic clay (GCL) – composed of bentonite to protect the liner from tears or punctures and swells/hydrates in the presence of free liquids. • A layer of 40 mil HDPE black textured • A layer of 250 mil drainage geo-composite • Final layer of GCL – to limit rainwater infiltration reaching cap geo-composite and HDPE liner, loosely hand graded. The cover system for the containment cell will be constructed at a slope 4:1 horizontal/vertical. The containment cell will be generally flat across the top of the mound with drainage as shown on the Drawings. Remedial Design Drawing C-331 shows the final grading plan and references cross section details. The top of the cap system will be sloped to drain to the perimeter of the containment cell. The drainage system will consist of continuous geonet to promote drainage off the 40-mil HDPE top geomembrane liner. Soil subgrade surface preparation will be performed in accordance with Section 31 00 00 of the soil RD specification. Rocks larger than 1/2 inch in diameter and any other material which could damage the GCL will be removed from the surface on which GCL is to be placed. Construction equipment tire or track deformations beneath the GCL will not be greater than 1.0 inch in depth. Each day during placement of GCL, the QC Inspector and installer will inspect the surface on which GCL is to be placed and certify in writing that the surface is acceptable. GCL will be installed as soon as practical after completion and approval of the subgrade preparation. Rolls will be delivered to the work area in their original packaging. Immediately prior to deployment, the packaging will be carefully removed without damaging the GCL. GCL which has been hydrated prior to being covered by an overlying geomembrane or a minimum of 18 inches of cover soil will be removed and replaced. Hydrated GCL is defined as having become soft as determined by squeezing the material with finger pressure or material which has exhibited swelling. Construction equipment may be used to deploy GCL. On side slopes, GCL will be Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-30 anchored at the top and deployed down the slope to minimize wrinkles. Dragging of GCL panels over the ground surface will be minimized. The QC Inspector has the option of requiring the use of a slip sheet. Deployed GCL panels shall lie flat on the subgrade surface, with no wrinkles or folds. Where anchor trenches will be placed as shown on drawing C-331 of the soil RD. The front edge of the trench shall be rounded so as to eliminate sharp corners that could damage the GCL. The GCL shall extend down the front wall and across the bottom of the anchor trench. Soils used for backfill shall have a maximum particle size of 1.0 inch and shall be placed in two lifts. Compaction and testing requirements are described in Section 31 00 00 of the soil RD Specification. 4.8.1.1. Drainage System Concurrent with placement of the geo-composite drainage layer, drainage controls will be constructed by the liner construction subcontractor. The purpose of the drainage system is to direct rainwater run-on away from the cap. The drainage geo-composite will be extended past the limits of the cap system to terminate in rip rap at the toe of the slope. The rip rap will protect the toe of the cover soil and the terminated end of the drainage net. The discharge from the geonet system will be collected at the perimeter of the containment cell and directed to natural drainage. This water will never have been in contact with the contaminated soil in the containment cell. Drainage layer installation requirements are described soil RD specification Section 31 05 20 Subsections 3.1.1 through 3.1.5 4.8.1.2. Anchor Trench Anchor shelves will be excavated along each cell boundary by ER using a compact excavator, to a depth and dimensions of at least 24” deep by 18’ wide. Once the liner is in place and secured, the anchor shelf will be backfilled with a minimum of 4” competent clay and compacted, in accordance with soil RD drawing C-601. Additional backfill material may include any remaining clean overburden, off-site borrow and gravel. The anchor trench will be dug with an excavator to the design depth, and subsequent backfill will be placed and graded with a tracked skid steer. The compaction will be performed with a vibratory plate compactor or similar device. 4.8.1.3. 40mil Liner Install The specialty subcontractor will mobilize to the site and furnish and install 38,000 SF of GCL, 40 Mil HDPE Black Textured Liner, and FabriNet 250 Mil double sided 6oz (drainage geocomposite). The HDPE liner will be unrolled onto containment cell in continuous sheets. The seams between sheets of the HDPE liner will be welded and pressure tested by the subcontractor. The top of the cap system will be sloped to drain to the perimeter of the containment cell. The drainage system will consist of continuous geonet to promote drainage off the 40-mil HDPE on top of the geomembrane liner. The net includes a bonded geotextile filter to separate the net from the overlying soil. The geonet will be extended past the limits of the cap system to terminate in rip rap at the toe of the slope. The rip rap will protect the toe of the cover soil and the terminated end of the drainage net. 4.8.2. 18” Soil Layer Once an electric leaks survey of the containment cap has been completed and any punch-list items identified and addressed, clean, granular fill material will begin to be placed on the cap liner. A Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-31 total of eighteen (18) inches of off-site fill will be used and added in six (6) inch lifts, graded, and compacted in accordance with soil RD specification Section 02 56 13 Subsection 3.8 and Section 02 66 00 Subsections 3.2.1 and 3.2.1.1. Care will be used to protect the liner from damage. Any foreign vegetative debris, rocks, or other materials will be removed between lifts, as necessary. ER will provide a clean testing certificate from the fill supplier. 4.8.2.1. Compaction The 18” backfill layer and anchor trench will be compacted to 90% of the maximum Standard Proctor Density compaction in 12-inch lifts. Finish compaction will be achieved by sheepsfoot rollers, or other approved equipment. Compaction will be verified by either test procedure ASTM D698 (Proctor) or ASTM D6938 (Nuclear Density). Compaction testing will be performed at a frequency of once per 10,000 square feet per lift. Compaction efforts will be performed with a dozer and if additional efforts are needed a designated sheepsfoot roller will be utilized. ER will subcontract a geotechnical subcontractor to conduct compaction testing to verify that 90% compaction has been met. Any lift not passing initial testing will be re-rolled to achieve the desired result. If an area is too wet to pass, ER may have to perform an undercut of an area and place a drier material to get the proper compaction. ER may elect to till the surface and aerate in lieu of undercut, if possible, then respread once moisture has diminished. 4.8.3. 6” Topsoil A secondary six (6) inch borrow layer will be added, with the final layer graded and compacted. This layer will be lightly tilled and aerated to allow for populating the top of the cap with a combination of native grasses and vegetation. The topsoil will be dumped directly from the delivery truck, if possible, onto the subgrade surface. A dozer with be utilized to spread the topsoil to the design thickness. 4.8.4. Install Rip Rap / Drainage Features Once the cap has been installed, riprap will be placed to limit erosion along the cap perimeter and serve to provide secondary bedding/anchoring of the cap. This material will also serve to capture/collect wood and leaves before they can affect stormwater drainage pathways and collection sumps. A perimeter swale will be constructed to direct stormwater runoff during heavy rain events and minimize the amount of entrained sediment in the storm water from leaving the site. The swale’s dimensions may vary based on topography but would normally involve installation of the swale to a depth of six (6) inches and a width of three (3) feet. The rip-rap material will be placed with an excavator bucket onto the prepared subgrade or may need to be placed with a track skid steer depending on terrain or space restrictions. Rip-rap placement will be conducted in accordance with soil RD specification Section 31 00 00 Subsection 3.7.1.1. The riprap will then be spread to the design thickness with the excavator bucket, ER ground personnel will fill in the void spots by hand to have an even and uniform appearance. 4.8.5. As-built Survey of Cap/Containment Donaldson, Garrett and Associates, the Subcontracted NC land surveyor, will be tasked to produce a post-construction topographic survey of the capped containment cell. The containment cell as- built survey will include identification of the cell boundary, surface elevation grading of the containment area and pertinent site features such as drainage features. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-32 4.9 SITE RESTORATION ACTIVITIES Upon completion of the project, ER will remove all signs, barricades, haul roads, temporary fences, and any other temporary structures from the site. After removal of trailers, materials, and equipment from within the site area. ER will restore areas used during the performance of the contract to the original, or better, condition. ER will remove gravel used to traverse grassed areas and restore the area to its original condition. All soil excavation areas will be seeded with grass per the plans and specifications. If wetlands are determined to need to be excavated due to final delineation in the southeast of the site during pre-RA field investigations, they will be restored. ER will coordinate with the North Carolina Office of Erosion and Sediment Control and Yadkin Soil and Water Conservation District Office to determine appropriate seed types, mixture, and purity requirements for temporary and permanent seeding. Seed will be selected to maximize native species and applied by ER using a broadcast spreader, or equivalent. The portion of the 2-foot clay layer covering the closed surface impoundment which will be disturbed by excavation activities will be replaced, as depicted in drawing C-311 of the soil RD. A 1-ft thick vegetative layer (topsoil and grass) will be added to the land farm cap. Additionally, the closed surface impoundment cap will be graded as needed so that water runs off the area instead of collecting and a 6-inch-thick vegetative layer will be added (topsoil and grass), as shown on Soil RD Drawing C-311. ER will select vegetation resistant to the invasive kudzu vines growing on the Site. 4.9.1. Containment Cell Restoration of the cap area and final grading of the land-farm cap and surface impoundment will involve use of various grass, such as mountain oak grass, red fescue, and bermuda grass blends. A blended grass seed mix will provide year-round erosion cover and improve soil stability. Small trees that are native to the area, such as dogwood, redbud, and red cedar may be planted, along with a variety of shrubs (under 4’), such as holly, boxwood, and hydrangea will be used for additional erosion control and stabilization. In accordance with soil RD specification Section 02 66 00 Subsection 1.3, only small trees having shallow root structures will be chosen, in order to prevent their penetration into the drainage layer. 4.9.1.1. O&M Watering Containment Cell Only Restored areas will be watered to help establish the grass and vegetative cover in the containment cell area only. Compost erosion features, such as waddles or erosion mats, will be installed to filter wood, debris, or eroded soils will be installed and in place prior to final restoration, planting, and seeding. 4.9.2. ISS Locations ISS areas will be seeded with grass per the plans and specifications. ER will coordinate with the North Carolina Office of Erosion and Sediment Control and Yadkin Soil and Water Conservation District Office to determine appropriate seed types, mixture, and purity requirements for temporary and permanent seeding. Seed will be selected to maximize native species and applied by ER using a broadcast spreader, or equivalent. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 4-33 4.9.3. Fence Installation Concurrent with restoration of the cap, and repairs to the surface impoundment and land-treatment unit areas, ER will subcontract a fence company to install a permanent six (6) foot tall, chain-link fence around the site, with posts cemented in place. Fence posts will be installed and leveled. Any surface obstructions, such as wood, rock, or other materials will be removed from the final fence area. Posts will be allowed to cure overnight prior to installing the remainder of the fence panels. A permanent swing gate will be installed, with sufficient width to allow a twenty (20) foot opening for larger trucks and equipment anticipated for use in the secondary ISEB treatment. A padlock will be installed on the outer fence with keys retained by ER and the RPM, and/or other parties as directed by the RPM. Fence materianls and construction will be in accorcdance with soil RD specification Section 32 31 13 and Drawings C-602 and C-603. 4.9.4. Surveys ER will task DGA, the subcontracted land surveyor to provide a final, as-built survey of the HCC Site at the conclusion of the Remedial Action construction. The final Site survey will include identification of the property boundaries, pertinent site features including, but not limited to, buildings, roadways, utility poles, streams and other drainage features, areas covered with concrete, locations of benchmarks, and locations of utilities, and as-built features of the construction including, but not limited to, injection points, and monitoring wells. 4.9.4.1. As Built Survey of Site [without cap] ER will task DGA to produce an as-built topographic survey that will be produced of the three-acre site property, excluding the capped containment cell. This survey will identify the property boundaries and pertinent site features related to the excavations. 4.10 DEMOBILIZATION ER will request a walk-through within 14 days of the project completion date to establish a possible punch list of items necessary to complete prior to a final walk-through and acceptance. After any punch list items have been addressed, ER will request a final walk through with all parties for approval and site acceptance prior to ER’s departure from site. At that time ER will begin to demobilize any remaining equipment, materials, trailers, electrical disconnects, storage units, etc. 4.11 GROUNDWATER INJECTION ACTIVITIES -PHASE 2 Following the initial primary ISEB treatment, monitoring wells within and near the ISEB treatment areas will be sampled quarterly during the first year (two events) to evaluate the effectiveness of the injections in distributing ISEB amendments in the subsurface. The soil RA will be completed in approximately six months following the initial primary ISEB treatment. Monitoring wells abandoned during the soil RA will be re-installed as part of the soil RA site restoration activities. Therefore, the first quarterly performance monitoring will occur at least six months following the initial primary ISEB treatment. Following the two quarterly performance monitoring events, the results will be evaluated by HGL and EPA to determine whether additional ISEB injections are needed, or if additional monitoring may be required prior to making the decision. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 5-34 It is anticipated that secondary ISEB Treatment would be limited in scope to a subset of injection locations selected by EPA, NCDEQ, and HGL. Injection locations selected for secondary ISEB treatment located outside the solidification areas would be conducted using DPT. However, it is anticipated that locations for reinjection within the footprint of solidification remediation areas would be conducted using rotary sonic drilling. The planning for the secondary treatment event and the procurement of ISEB amendment and injection subcontractor will be performed by ER based on the quarterly monitoring results and subsequent recommendations. 5. REMEDIAL ACTION REPORT ER will complete all Task Order and Contract reporting requirements and submit per appropriate delivery dates and deadlines. This includes the submittal of a Final Remedial Action Report following the guideline document provided within the FOSR. This report will be compiled as site work progresses and will be amended as necessary to meet any specific EPA request/s. ER will Prepare the report in accordance with guidance document EPA 542-B-98-007 and include the following report elements: • Executive Summary • Type of Action o Period of Operation o Quantity of Material Treated During Application o Performance Objectives o Site Logistics/Contacts • Matrix and Contaminant Description o Matrix Identification o Site Geology/Stratigraphy o Contaminant Characterization o Contaminant Properties o Nature and Extent of the Contaminants o Matrix Characteristics Affecting Treatment Cost or Performance • Treatment System Description o Primary Treatment Technology Types o Supplemental Treatment Technology Types o Timeline o Operating Parameters Affecting Treatment Cost or Performance • Treatment System Performance o Treatment Performance Data o Data Assessment and Deviations from Standard Performance o Material Balances o Target Contaminant and Operating Conditions o Target Contaminant and Removal Efficiencies o Characteristics of Treated Material • Performance Data Quality Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 6-35 • Remedial Action Cost o HTRW - Remedial Action Work Breakdown Structure o Pre-Treatment Costs o Costs Directly Associated with Treatment o Post-Treatment Costs • Regulatory/Institutional Issues • Observations and Lessons Learned o Cost Observations and Lessons Learned o Performance Observations and Lessons Learned o Other Observations and Lessons Learned 6. REFERENCES U.S. Environmental Protection Agency (EPA), 2018. Record of Decision, Holcomb Creosote Company Superfund Site. August. EPA, 1995. Remedial Design/Remedial ActionHandbook. OSWER 9355.0-04B, EPA 540/R-95/059. June. EPA, 1992. Remedial Action Report Guidance. OSWER 9355.0-39FS. June. HydroGeoLogic, Inc (HGL), 2021. Final Soil Remedial Design, Holcomb Creosote Company Site. December. HydroGeoLogic, Inc (HGL), 2021. Pre-Final (90%) Soil Remedial Design, Holcomb Creosote Company Site. March. HydroGeoLogic, Inc (HGL), 2022. Final Groundwater Remedial Design, Holcomb Creosote Company Site. August. HydroGeoLogic, Inc (HGL), 2022. Final Groundwater Remedial Design, Holcomb Creosote Company Site. August. Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 6-36 Tables Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 6-37 Table 3-1 Cleanup Levels Remedial Action Work Plan Holcomb Creosote Company Site, Yadkinville, Yadkin County, NC Contaminant of Concern Groundwater Cleanup Level (μg/L) Soil Cleanup Level (μg/kg) Sediment Cleanup Level (mg/kg) Basis Cobalt 9 NA NA Noncancer hazard Quotient=1 Iron 20,256 NA NA North Carolina Groundwater Standard Manganese 694 NA NA Noncancer hazard Quotient=1 1,1-Biphenyl 400 NA NA North Carolina Interim Maximum Allowable Concentration 2-Methylnaphthalene 30 NA NA North Carolina Groundwater Standards (groundwater) / Site-specific groundwater protection calculation (soil) Acenaphthalene 1,736 NA NA Dibenzofuran 28 NA NA Naphthalene 6 180 NA Benzo(a)pyrene TEQ 0.005 NA NA Ethylbenzene 600 NA NA Total PAHs NA NA 198 Maximum Acceptable Toxicant Concentration Table 4‐1 Groundwater Treatment Locations and Quantities  Remedial Action Work Plan  Holcomb Creosote Company Site, Yadkinville, Yadkin County, NC Injection Point Top of Injection (ft bgs) Bottom of Injection (ft bgs) Treatment  Feet Estimated  Gallons of  Injectant Slurry Concentration  of Injectant Estimated lbs  of Injectant  Powder A1 21 26 5 135 7.0% 704 A2 22 27 5 135 7.0% 704 A3 12 29 17 459 7.0% 2394 A4 13 31 18 486 7.0% 2535 B1 21 26 5 135 7.0% 704 B2 12 29 17 459 7.0% 2394 B3 12 32 20 540 7.0% 2817 B4 12 32 20 540 7.0% 2817 B5 13 31 18 486 7.0% 2535 C1 12 26 14 378 7.0% 1972 C2 12 30 18 486 7.0% 2535 C3 12 33 21 567 7.0% 2958 C4 12 33 21 567 7.0% 2958 C5 12 32 20 540 7.0% 2817 C6 12 31 19 513 7.0% 2676 D1 9 31 22 594 7.0% 3099 D2 10 33 23 621 7.0% 3240 D3 12 33 21 567 7.0% 2958 D4 11 32 21 567 7.0% 2958 D5 11 31 20 540 7.0% 2817 D6 11 31 20 540 7.0% 2817 E1 12 31 19 513 7.0% 2676 E2 9 31 22 594 7.0% 3099 E3 9 30 21 567 7.0% 2958 E4 10 29 19 513 7.0% 2676 E5 14 28 14 378 7.0% 1972 E6 10 29 19 513 7.0% 2676 F1 12 27 15 405 7.0% 2113 F2 8 27 19 513 7.0% 2676 F3 8 27 19 513 7.0% 2676 F4 8 28 20 540 7.0% 2817 F5 14 28 14 378 7.0% 1972 F6 8 29 21 567 7.0% 2958 G1 6 27 21 567 7.0% 2958 G2 6 27 21 567 7.0% 2958 G3 7 28 21 567 7.0% 2958 G4 7 30 23 621 7.0% 3240 G5 7 31 24 648 7.0% 3380 G6 7 30 23 621 7.0% 3240 G13 8 31 23 621 8.5% 3240 G14 8 31 23 621 8.5% 3240 G15 7 31 24 648 8.5% 3380 G16 27 32 5 135 7.0% 704 G17 28 33 5 135 7.0% 704 G18 29 34 5 135 7.0% 704 Table 4‐1 Groundwater Treatment Locations and Quantities  Remedial Action Work Plan  Holcomb Creosote Company Site, Yadkinville, Yadkin County, NC Injection Point Top of Injection (ft bgs) Bottom of Injection (ft bgs) Treatment  Feet Estimated  Gallons of  Injectant Slurry Concentration  of Injectant Estimated lbs  of Injectant  Powder H2 6 27 21 567 7.0% 2958 H3 6 28 22 594 7.0% 3099 H4 8 30 22 594 7.0% 3099 H5 8 31 23 621 7.0% 3240 H6 6 30 24 648 7.0% 3380 H12 16 30 14 378 8.5% 1972 H13 6 29 23 621 8.5% 3240 H14 6 29 23 621 8.5% 3240 H15 6 29 23 621 8.5% 3240 H16 25 30 5 135 7.0% 704 H17 26 31 5 135 7.0% 704 H18 27 32 5 135 7.0% 704 H19 28 33 5 135 7.0% 704 H20 29 34 5 135 7.0% 704 I2 5 25 20 540 7.0% 2817 I3 8 23 15 405 7.0% 2113 I4 8 22 14 378 7.0% 1972 I5 8 24 16 432 7.0% 2254 I6 5 25 20 540 7.0% 2817 I12 16 28 12 324 8.5% 1690 I13 16 28 12 324 8.5% 1690 I14 16 27 11 297 8.5% 1549 I15 5 28 23 621 8.5% 3240 I16 5 28 23 621 8.5% 3240 I17 24 29 5 135 7.0% 704 I18 25 30 5 135 7.0% 704 I19 26 31 5 135 7.0% 704 I20 27 32 5 135 7.0% 704 I21 29 34 5 135 7.0% 704 J3 5 18 13 351 7.0% 1831 J4 8 18 10 270 7.0% 1409 J5 8 17 9 243 7.0% 1268 J6 8 19 11 297 7.0% 1549 J12 16 28 12 324 8.5% 1690 J13 16 27 11 297 8.5% 1549 J14 16 27 11 297 8.5% 1549 J15 5 27 22 594 8.5% 3099 J16 5 28 23 621 8.5% 3240 J17 5 28 23 621 8.5% 3240 J18 24 29 5 135 7.0% 704 J19 25 30 5 135 7.0% 704 J20 27 32 5 135 7.0% 704 J21 28 33 5 135 7.0% 704 K4 5 15 10 270 7.0% 1409 K5 5 17 12 324 7.0% 1690 Table 4‐1 Groundwater Treatment Locations and Quantities  Remedial Action Work Plan  Holcomb Creosote Company Site, Yadkinville, Yadkin County, NC Injection Point Top of Injection (ft bgs) Bottom of Injection (ft bgs) Treatment  Feet Estimated  Gallons of  Injectant Slurry Concentration  of Injectant Estimated lbs  of Injectant  Powder K6 8 16 8 216 7.0% 1127 K12 4 28 24 648 8.5% 3380 K13 5 28 23 621 8.5% 3240 K14 5 28 23 621 8.5% 3240 K15 5 28 23 621 8.5% 3240 K16 5 29 24 648 8.5% 3380 K17 5 29 24 648 8.5% 3380 K18 25 30 5 135 7.0% 704 K19 25 30 5 135 7.0% 704 K20 26 31 5 135 7.0% 704 K21 28 33 5 135 7.0% 704 L13 3 29 26 702 8.5% 3662 L14 4 29 25 675 8.5% 3521 L15 4 30 26 702 8.5% 3662 L16 5 30 25 675 8.5% 3521 L17 5 30 25 675 8.5% 3521 L18 26 31 5 135 7.0% 704 L19 26 31 5 135 7.0% 704 L20 27 32 5 135 7.0% 704 L21 28 33 5 135 7.0% 704 L22 29 34 5 135 7.0% 704 M13 2 28 26 702 8.5% 3662 M14 3 30 27 729 8.5% 3803 M15 4 30 26 702 8.5% 3662 M16 4 31 27 729 8.5% 3803 M17 5 31 26 702 8.5% 3662 M18 27 32 5 135 7.0% 704 M19 28 33 5 135 7.0% 704 M20 29 34 5 135 7.0% 704 M21 30 35 5 135 7.0% 704 M22 31 36 5 135 7.0% 704 N14 2 29 27 729 8.5% 3803 N15 2 30 28 756 8.5% 3944 N16 3 31 28 756 8.5% 3944 N17 4 32 28 756 8.5% 3944 N18 28 33 5 135 7.0% 704 N19 29 34 5 135 7.0% 704 N20 30 35 5 135 7.0% 704 N21 32 37 5 135 7.0% 704 N22 33 38 5 135 7.0% 704 N23 35 40 5 135 7.0% 704 O14 1 29 28 756 8.5% 3944 O15 1 30 29 783 8.5% 4085 O16 2 31 29 783 8.5% 4085 O17 3 32 29 783 8.5% 4085 Table 4‐1 Groundwater Treatment Locations and Quantities  Remedial Action Work Plan  Holcomb Creosote Company Site, Yadkinville, Yadkin County, NC Injection Point Top of Injection (ft bgs) Bottom of Injection (ft bgs) Treatment  Feet Estimated  Gallons of  Injectant Slurry Concentration  of Injectant Estimated lbs  of Injectant  Powder O18 4 33 29 783 8.5% 4085 O19 30 35 5 135 7.0% 704 O20 31 36 5 135 7.0% 704 O21 33 38 5 135 7.0% 704 O22 35 40 5 135 7.0% 704 O23 37 42 5 135 7.0% 704 P15 1 30 29 783 8.5% 4085 P16 2 31 29 783 8.5% 4085 P17 3 32 29 783 8.5% 4085 P18 4 34 30 810 8.5% 4226 P19 31 36 5 135 7.0% 704 P20 33 38 5 135 7.0% 704 P21 35 40 5 135 7.0% 704 P22 37 42 5 135 7.0% 704 P23 39 44 5 135 7.0% 704 P24 40 45 5 135 7.0% 704 Q18 4 35 31 837 8.5% 4366 Q21 36 41 5 135 7.0% 704 Q22 38 43 5 135 7.0% 704 Q23 40 45 5 135 7.0% 704 Q24 42 47 5 135 7.0% 704 R16 1 32 31 837 8.5% 4366 R17 2 33 31 837 8.5% 4366 R22 40 45 5 135 7.0% 704 R23 42 47 5 135 7.0% 704 R24 43 48 5 135 7.0% 704 R25 45 50 5 135 7.0% 704 S16 2 32 30 810 8.5% 4226 S17 2 34 32 864 8.5% 4507 S18 3 36 33 891 8.5% 4648 S19 33 38 5 135 7.0% 704 S23 44 49 5 135 7.0% 704 S24 46 51 5 135 7.0% 704 S25 47 52 5 135 7.0% 704 T16 2 33 31 837 8.5% 4366 T17 3 35 32 864 8.5% 4507 T18 4 37 33 891 8.5% 4648 T20 41 46 5 135 7.0% 704 T24 47 52 5 135 7.0% 704 U21 44 49 5 135 7.0% 704 U22 46 51 5 135 7.0% 704 V23 47 52 5 135 7.0% 704 Remedial Action Work Plan for Holcomb Creosote Company Site Contract Task Order No. 68HE0422F0073 April 2023 6-38 Figures DobbinsPondHaire RoadS hugart's M ill R oad£¤601Lake Hill DriveLas Brisas DriveLakewood TrailDobbins Mill RoadFigure 2-1 Site LocationLegendER - Remedial Action Work PlanHolcomb Creosote Site—Yadkinville, North Carolina0450900225Feet³\Source: HGL—Groundwater Remedial Design ArcGIS Online Imagery/Streets Map^_HolcombCreosote SiteNORTHCAROLINAStatewide Location£¤601£¤421HolcombCreosote SiteGeneral Location021MilesHolcomb Creosote Property Boundary D D D D D DDDDDDDDDDDDDDDDD D D D DDDD DDDDDDDDDDDDDDD D D D D £¤601Drip Pad(removed)StorageOfficeTreatment Vessel(removed)Distillation Evaporator(removed)FormerDrum Storage AreaConcrete Pit(removed)Creosote Work Tank(removed)Creosote Storage Tank(removed)Gasoline UST(removed)Steel Settling Tank(removed)Overflow CreosoteStorage Tank(removed)Diesel Tank(removed)U n a me d T r ib u ta r yFigure 2-2Site Facility PlanLegendER - Remedial Action Work PlanHolcomb Creosote Site—Yadkinville, North Carolina06012030Feet³\Source: HGL—Groundwater Remedial Design ArcGIS Online Imagery (Clarity)Note:UST=underground storage tankFenceDSurface Water CourseWetlandsLandfarm (closed)Existing StructureFormer StructureSurface Impoundment (closed) ID WBS Task NameDuration StartFinish Predecesso00Project Schedule Factor 1 and 2261 daysMon 12/5/22Mon 12/4/2311On-Site Activities (General Conditions)186 daysMon 3/20/23Mon 12/4/2322Phase 1 - Injection #1, Soil Excavation and Consolidation, NAPL- Soil Stabilization140 daysMon 3/20/23Fri 9/29/2332.1Procurement65 daysMon 12/5/22Fri 3/3/2342.1.1Procurement of Subcontractor50 daysMon 12/5/22Fri 2/10/2352.1.2Submittals Review and Approval, Pre-Construction Meetin15 daysMon 2/13/23Fri 3/3/23462.2Mobilization and Site Preparation11 daysMon 3/20/23Mon 4/3/2372.2.1Mobilization1 dayMon 3/20/23Mon 3/20/23582.2.2Temporary Facilities, Erosion Controls, SW Ditches/Berms, and Temporary Roads7 daysTue 3/21/23Wed 3/29/23792.2.3Site Clearing and Utilities3 daysThu 3/30/23Mon 4/3/238102.3Demolition Activities14 daysTue 4/4/23Fri 4/21/23112.3.1Lead and ACM Abatement Activities4 daysTue 4/4/23Fri 4/7/239122.3.2Structure Demo5 daysMon 4/17/23Fri 4/21/2311132.4Transportation and Disposal Ops19 daysTue 4/4/23Fri 4/28/23142.4.1Recycling1 dayTue 4/4/23Tue 4/4/23152.4.2C&D Building Debris5 daysMon 4/17/23Fri 4/21/2311162.4.3Transformer (missing from site/presumed stolen)3 daysMon 4/17/23Wed 4/19/2311172.4.4ACM4 daysTue 4/4/23Fri 4/7/239182.4.5Lead4 daysTue 4/4/23Fri 4/7/239192.4.6Manifest Tracking and CERLCA Reporting1 dayMon 4/24/23Mon 4/24/2312202.4.7Surveying3 daysWed 4/19/23Fri 4/21/2319212.4.8Well Abandonment5 daysMon 4/24/23Fri 4/28/2320222.5Injection #129 daysMon 4/17/23Thu 5/25/23232.5.1Driller Mob + Set-up Activities 3 daysMon 4/17/23Wed 4/19/23242.5.2Injection Dosage26 daysThu 4/20/23Thu 5/25/2323252.6Soil Excavation and On-site Consolidation61 daysFri 5/26/23Fri 8/18/23262.6.1Soil Excavation Delineation5 daysFri 5/26/23Thu 6/1/2324272.6.2Temporary Soil Stockpile Construction5 daysFri 6/2/23Thu 6/8/2326AugSepOctNovDecJanFebMarAprMayJunJulAugSepOctNovDecJan2022Qtr 4, 2022Qtr 1, 2023Qtr 2, 2023Qtr 3, 2023Qtr 4, 2023Qtr 1, 2Page 1 ID WBS Task Name Duration Start Finish Predecesso282.6.3Excavation - Clean Overburden7 daysFri 6/9/23Mon 6/19/2327,26292.6.4Excavation - Contaminated Soil30 daysTue 6/20/23Mon 7/31/2328302.6.5Consolidation/Containment Cell Stabilization35 daysTue 6/20/23Mon 8/7/2328312.6.6As-Excavated Survey1 dayTue 8/8/23Tue 8/8/2330322.6.7Rough Grade and Backfill Compaction4 daysWed 8/9/23Mon 8/14/2331332.6.8Restoration4 daysTue 8/15/23Fri 8/18/2332342.7NAPL- Impacted Soil Stabilization20 daysMon 8/21/23Fri 9/15/23352.7.1Soil Stabilization Process10 daysMon 8/21/23Fri 9/1/23362.7.2NAPL Soil Stabilization Outside Containment Cell10 daysMon 9/4/23Fri 9/15/2335372.7.3Solidification QC Testing20 daysMon 8/21/23Fri 9/15/23383Phase 2 - Cap Construction and Site Restoration56 daysMon 9/18/23Mon 12/4/23393.1Procurement10 daysMon 3/6/23Fri 3/17/23403.1.1Submittals Review and Approval for Phase 210 daysMon 3/6/23Fri 3/17/23413.2Cap Construction28 daysMon 9/18/23Wed 10/25/23423.2.1Subcontractor Mob1 dayMon 9/18/23Mon 9/18/2337433.2.2Liner System Installation7 daysTue 9/19/23Wed 9/27/2342443.2.318" Soil Layer10 daysThu 9/28/23Wed 10/11/2343453.2.46" Topsoil3 daysThu 10/12/23Mon 10/16/2344463.2.5Install Rip-Rap/ Drainage Features5 daysTue 10/17/23Mon 10/23/2345473.2.6As-Built Survey of Cap/Containment 2 daysTue 10/24/23Wed 10/25/2346483.3Site Restoration23 daysThu 10/26/23Mon 11/27/23493.3.1Land Farm and Former Impoundment10 daysThu 10/26/23Wed 11/8/2346503.3.2Containment Cell (Hydroseed)1 dayThu 11/9/23Thu 11/9/2349513.3.3ISS Locations (Hydroseed)2 daysFri 11/10/23Mon 11/13/2350523.3.4Fence/Gate Installation10 daysTue 11/14/23Mon 11/27/2351533.3.5As-Built Surveys5 daysThu 10/26/23Wed 11/1/23543.4Demobilization5 daysTue 11/28/23Mon 12/4/2352AugSepOctNovDecJanFebMarAprMayJunJulAugSepOctNovDecJan2022Qtr 4, 2022Qtr 1, 2023Qtr 2, 2023Qtr 3, 2023Qtr 4, 2023Qtr 1, 2Page 2