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3.0 PRELIMINARY ASSESSMENT <br />At B88's request, Dames & Moore conducted a preliminary site assessment of the Montgomery <br />Pit facility on November 11 and 12, 1998. During the site assessment, Dames & Moore <br />performed initial site reconnaissance, mapped the major features of the facility, prepared a <br />photographic record of the site assessment, and collected environmental samples. A schematic <br />site plan of the Montgomery Pit facility prepared during the site assessment is presented in <br />Figure 2. The assessment photographic record is presented in Appendix A of this SAP. <br />' On Thursday, November 12, 1998, Dames & Moore personnel collected samples of <br />environmental media and process residuals potentially affected by the released chemicals. <br />Grab samples were collected from the remaining minus'/: inch road base stockpile, the minus <br />'/+ inch road base stockpile, and the hot plant bag house. One composite sample was also <br />collected from a small stockpile of washed sand. <br />' The minus'/: inch and minus '/. inch road base piles were screened with direct reading field <br />instruments prior to collecting the grab samples. The field screening technique consisted of <br />ambient temperature headspace (ATH) tests performed at established intervals around the <br />stockpiles. Dames 8 Moore selected this screening method based on the MSDS indicating the <br />released weed killer consisted mainly of petroleum hydrocarbons, i.e. diesel fuel. The ATH <br />screening technique was used to provide a qualitative estimate of the diesel fuel concentrations <br />' within the piles, thereby also indicating which materials were potentially affected by the released <br />weed killer. <br />' ATH screening samples were collected by establishing transects around the perimeters of the <br />piles with sampling points at 20-foot intervals. Approximately 4 ounces of road base were <br />collected at each sampling point. Samples were placed in clean plastic bags, placed inside <br />Dames & Moore's vehicle, and allowed to equilibrate to the ambient temperature inside the <br />vehicle (approximately 60° F.). The sample bags were then tested using aphoto-ionization <br />detector (PID) calibrated to a standard calibration gas consisting of 100 parts per million (ppm) <br />iso-butylene in air. A total of 12 ATH samples were collected and tested from the minus '/~ inch <br />pile and 8 from the minus'/. inch pile. Based on the ATH testing results, only 1 of the 20 <br />screening samples appeared to be affected by petroleum hydrocarbons. These results <br />indicated the affected materials were confined to a small portion of the remaining minus'/~ road <br />base pile. Dames 8 Moore collected samples for laboratory analysis from each road base pile. <br />After screening the stockpiles, grab samples were collected from the areas exhibiting the <br />highest ATH test results from each pile. These samples were submitted for laboratory testing. <br />During the preliminary assessment, Dames & Moore also collected wipe samples from <br />containers identified as the sources of the released chemicals. The purpose of collecting and <br />analyzing these samples was to confirm the presence and identity of the released substances. <br />This initial sampling activity was not designed to characterize the extent of possibly affected <br />media. The chemical identification information gathered during this visit was intended for use in <br />1 preparing this detailed SAP. <br />Preliminary assessment samples were analyzed by Evergreen Analytical Laboratories, Inc. in <br />_ Wheat Ridge, Colorado. Analytical parameters included the following: <br />• Chlorinated and phenoxy acid weed killers by EPA Method 8150 <br />' B&B Excavating, Inc., Edwards, Colorado December 17, 1998 <br />Montgomery Pit Facility 39210-003-034 <br />Draft Sampling and Analysis Plan 9 DAMES 8 MOORS <br />