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26 November 2019 AdvancedGeo AGE Project Nos. 98-0448 and 04-1239 Environmental Page 2 of 3 Seventeen (17) of the groundwater monitoring wells, all of the soil-vapor extraction wells, and all of the air-sparge wells are single-completed with 2-inch diameter well casings in an 8-inch diameter borehole. One (1) of the groundwater monitoring wells (MW-4A, MW-413) is double completed with 2-inch diameter well casing in a 10-inch diameter borehole. Two (2) of the dual-phase extraction wells are single-completed with diameter 4-inch well casing in a 10-inch diameter borehole. Two of the dual-phase extraction wells are single-completed with 4-inch diameter well casings in a 12-inch borehole. The shallow soil-vapor well is single-completed with a Teflon tube in a 4-inch borehole. The site and the surrounding area are illustrated in Figure 1. Structures, soil borings and well locations are illustrated in Figures 2 and 3. Well construction details are summarized in Table 1. 2.0. PROCEDURES As required, a health and safety plan will be prepared in accordance with Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities (National Institute for Occupational Safety and Health Administration, U.S. Coast Guard and U.S. Environmental Protection Agency, 1985). Prior to drilling activities, each proposed drilling location will be clearly marked and utility clearance obtained through Underground Service Alert. A well abandonment/destruction permit will be obtained from the SCDHS; additionally, the SCDHS will be notified a minimum of 48-hours prior to commencement of well destruction activities. Prior to well destruction activities, all wells will be checked for total depth and well integrity using a Solinst water level meter. Any obstructions found in the well will be removed. AGE is proposing to destroy wells MW-1 though MW-9, MW-12, MW-13, MW-15 through MW-21, VW-1 though VW-6, AW-1 though AW5, DPE1 through DPE-4, and SV-1 by removing all material within the original boreholes utilizing over-drill techniques. The abandonment of these wells will be performed utilizing a track-mounted CME-75 high torque mobile drill rig. All thirty-four wells will be drilled-out to one foot deeper than the total depth of the wells utilizing hollow-stem augers of a diameter at least % inch larger than the original borehole. All original well construction materials will be removed (including well casing, screen, filter pack, and annular seal) by the drill rig to ensure that no residual contamination is sealed within the abandoned borehole nor a filter pack remaining to act as a vertical conduit. All thirty-four excavated borings will be completely backfilled to surface grade with a cement grout mixture (Portland type II) and covered with either a concrete or asphalt, depending on the surrounding surface material. The grout mixture will consist of a ratio of six gallons water for every 94-pound sack of Portland type II cement. The drill rig hollow stem augers will be utilized as a tremie pipe installation of the grout seal.