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*W� ..i <br /> • The boreholes will be vacuum cleared and/or hand augered to 4 or 8 feet. The boreholes <br /> will then be drilled with a truck-mounted rotary drill, using hollow-stem continuous- <br /> flight augers. The boreholes will have an outside diameter of 8 inches when completed. <br /> • Soil samples from the boreholes will be collected and logged at intervals of <br /> approximately 5 feet in the vadose zone and then continuously in the saturated zone to <br /> the total depth of the boreholes to characterize subsurface lithology. Selected soil <br /> samples will be retained for laboratory analysis based on significant lithologic changes <br /> _ and/or organic vapor analyzer measurements. <br /> • The exploratory boring will be completed to a depth of approximately 60 feet. Upon <br /> .. completion of soil sampling, the exploratory boring will be abandoned with a cement <br /> grout containing less than 5 percent pure sodium bentonite. <br /> �- • Each injection point borehole will be completed with two nested stainless steel injection <br /> points (one point for the potential injection of ozone and one point for the potential <br /> injection of hydrogen peroxide). The boreholes will be advanced to a depth of <br /> approximately 40 feet. The ozone point will be installed at a depth of approximately 39 <br /> feet, and the hydrogen peroxide point will be installed at a depth of approximately 31 <br /> feet. A proposed well construction diagram is shown in Figure 2. <br /> • Each ozone injection point will be completed with a 3-foot length of%-inch-diameter <br /> well screen/diffuser at the end of the casing. Each hydrogen peroxide injection point will <br /> be completed with a 1-foot section of 1/2.-inch-diameter stainless steel well screen. Each <br /> ozone point and hydrogen peroxide point will be installed with a sand pack placed from <br /> approximately 1 foot below the screened interval to a depth of approximately 2 feet <br /> above the top of the screened interval. A bentonite seal (approximately 2 feet thick) will <br /> be placed above the deeper sand pack and hydrated before the shallower sand pack is <br /> established. After the shallower sand pack is established an additional 2 feet of bentonite <br /> will be placed above the shallower sand pack and hydrated, followed by cement grout (or <br /> a grout/bentonite mixture) and completed with a protective, lockable access vault, which <br /> _ will be mounted flush to grade. The exploratory boring and injection well point <br /> installations will be completed in accordance with the drilling and well installation and <br /> sampling protocols described in Appendix A and in accordance with local regulations. <br /> • The injection points will be developed using a peristaltic pump or bailer until the water is <br /> free of silt and apparent turbidity. <br /> Selected soil samples will be analyzed for: <br /> • Total Petroleum Hydrocarbons as gasoline. <br /> • Benzene, toluene, ethylbenzene, and xylenes. <br /> • Methyl t-butyl ether, t-butyl alcohol, diisopropyl ether, ethyl t-butyl ether, t-amyl methyl <br /> ether, ethylene dibromide, and 1,2-dichloroethane. <br /> • Aluminum, antimony, arsenic, barium, beryllium, cadmium, calcium, chromium (III and <br /> VI), cobalt, copper, iron, lead, magnesium, manganese, mercury, molybdenum, nickel, <br /> G:\P ,CMM942\MASTER\W WWW\W CM2&C 2 <br />