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_~ <br />May Excavation and Dismal <br />Once the lab results are obtained, regression analysis will be applied to determine if a correlation <br />exists between the PID readings of solid media and corresponding lab tests for Diesel, 2,4-D, <br />Bromacil and Dicamba. It is likely that this will be the case. ]t is possible, however, that the more <br />rapid deterioration of 2,4-D upon exposure to air and moisture may not result in a predictable <br />corzelation for this contaminant compared with the PID readings, which are specific ambient <br />temperature headspace (ATH) tests of hydrocarbons related to the diesel fuel. If a correlation cannot <br />be developed for PID readings vs. 2,4-D concentration, the PID will be used to isolate any material <br />which could possibly have 2,4-D above 10 mg/Kg. The PID reading for this cutoff level will be <br />agreed upon with the DMG based on the results of the February lab analysis. Any material above this <br />cutoff level will be spread out in an 8 inch thickness over a 6 inch thickness of compacted clay. This <br />is described in detail in Item 2 (2) of the next section. Under the aerobic conditions, the material <br />should rapidly lower in 2,4-D concentration and will be laboratory tested on a 20 feet x 20 feet <br />spacing until the concentration is less than 10 mg/Kg. The material will then be hauled to the <br />disposal facility. <br />In the more likely case of a correlation existing for all contaminants, the ATH tests using the PID <br />would be used to guide the excavation and disposal planned for May ] 999. The correlation will show <br />what PID reading will equate to a 2,4-D concentration of ]0 mg/Kg or more. Such material will be <br />treated as described above. <br />May was selected to provide the earliest period when weather-related problems were not likely to <br />occur. For the May 1999 excavation, a front end loader will be used to excavate the minus'/:inch <br />road base pile. At least 6 small samples will be collected at random from each machine bucket and <br />combined to conduct the PID readings. Depending on the correlated concentration of 2,4-D, the <br />material will either be taken to the Eagle County disposal facility, left on site or treated on site and <br />then taken to the landfill. These alternatives are described in detail in Item 2. ~ <br />The bag house dust has already been disposed of, as described in Item 3 of the next section. <br />