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DocuSign Envelope ID: F6E5B15D-6611-4749-BBCF-56530F14FFBD <br /> Work Plan&Cost Estimate for Remedial investigation—Monitor Well Installations <br /> ■ Hillsborough dump <br /> 1D No. NONCDO000483 <br /> -� Task Orders 483DP-7,8 and 9 <br /> purr <br /> S&ME Project No.4305-17-061 <br /> approved Standard Operating Procedures and Quality Assurance(SOP/QA) Manual(July 2070), previously <br /> approved by NCDEQ. <br /> Task 483DP-7 Work Plan/Proposal Preparation <br /> The following services were performed: <br /> Coordination with Orange County for Scope of Work guidance. <br /> Developed a drawing to present the proposed monitor well locations. <br /> Reviewed Groundwater Protection Rules for Orange County. <br /> U Solicited bids from subcontractors. <br /> Developed cost estimate spreadsheets. <br /> a Prepared field services schedule and task descriptions. <br /> Prepared this proposal and work plan. <br /> Task 483DP-8 Groundwater Assessment <br /> Subtask A Field Services <br /> Groundwater Protection Rules for Orange County and Proposal Assumptions <br /> Per the attached copy of Groundwater Protection Rules for Orange County(Rules), monitor wells that penetrate <br /> consolidated rock shall be subject to the Rules and require permits from the Orange County Health Department <br /> (OCHD) prior to construction. Most notably,the OCHD Rules require monitor wells (including temporary wells) <br /> that penetrate consolidated rock to be constructed with 6-inch steel outer casings and grouted. The placement of <br /> grout for each well must be visually inspected during construction in the field by OCHD staff. Likewise, <br /> abandonment of each well also requires inspection by OCHD staff. <br /> 5&ME previously installed 260 waste delineation borings at the site using hollow-stem augers. In general,rock <br /> was encountered at about eight feet below ground surface(bgs). Therefore,this proposal assumes most of the <br /> proposed wells will be subject to the OCHD Rules and require permits from OCHD. For budgeting purposes, bids <br /> received from drilling subcontractors include well construction methods in accordance the Rules and associated <br /> costs for using six-inch steel outer casings,allowing time for inspections, etc.,and using air-rotary drilling <br /> methods. Monitor well borings that encounter groundwater prior to encountering consolidated rock will not <br /> require air drilling,and will not require 6-inch steel outer casing. <br /> Monitor Well Installations <br /> Fifteen permanent groundwater monitor wells (MW-1 through MW-15)are proposed to be installed outside of <br /> the waste disposal area at the Locations shown on Figure 1. Borings will be advanced to an approximate depth of <br /> at least seven feet below the observed groundwater table(e.g. moist/wet conditions). This will be the termination <br /> depth of the borings and the depth to which the well screens will be installed. For budgeting purposes, a total of <br /> 340 feet of drilling depth is assumed. Monitor wells that penetrate consolidated rock will be constructed per the <br /> OCHD Rules, referenced above,with two-inch diameter, PVC well screens and casings within six-inch diameter <br /> steel outer casings. Well casings will be installed to approximately three feet above the ground surface(stick-up). <br /> For budgeting purposes,a total of 120 feet of steel casing is assumed. A sand pack will be installed in the boring <br /> March 5, 2019 2 <br />