ARCHIVED REPORTS XR0010073 - Laserfiche WebLink

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February 2, 2001 Wright Environmental Services, Inc Page 2 FIELD SURVEY We scanned the investigation areas with the EMLL instrumentation for the presence of buried utilities or other metallic objects This reconnaissance scanning consisted of covering the accessible portions of the survey area with bidirectional traverses spaced approximately four feet apart The presence of reinforced concrete east of the welding building precluded the use of the EMLL metal detector in that area During the survey, Wright Environmental Services observed that an exposed pipe at the northwest comer of the welding building (see Plate 1) was of a different construction, having a slightly larger diameter, than the other cut-off pipes along the edge of the concrete apron We used the EMLL instrumentation to specifically explore for subsurface extensions of that pine, or potentially related UST's Following the EMLL, we obtained GPR data along primary traverses oriented east/west in the southern portion of the survey area as well as in the vicinity of tl ie southernmost trailer GPR traverses were oriented north/south to the west and north of the welding building These GPR traverses were spaced approximately 4 feet apart to allow for detection of relatively small UST's The resultant GPR records were analyzed for reflection pattems characteristic of UST's and other features that could represent potential contaminant sources Additional traverses were performed • perpendicular to the primary traverses over suspect areas that required further definition As with the EMLL method, the reinforced concrete east of the welding buiiaing limited the effectiveness of GPR in that area The locations of detected subsurface features were painted on the ground surface RESULTS The interpreted results of the geophysical investigation are presented on the geophysical survey map, Plate 1 This man also shows the locations of the GPR traverses ants above ground cultural features No UST-like ouned objects were detected within the limits of the geoohysical investigation area The significant objects that were detected are comprised of the following subsurface features one anomalous GPR area, one small EMLL anomaly representing isolated bune'd metal, and a section of a suspected vent line In the course of the UST search, we detected several additional utilities including a suspected water line, and four undifferentiated utilities (utilities of an undetermined tyoe or nature) Our interpretations regarding these items are discussed further below Subsurface Features The GFR anomaly, as referred to on Plate 1, was detected east of the muffler building We observed this feature on the GPR records as an area of aiscontinuous subsurface reflection patterns that may be indicative of burred debris It is located in the vicinity of the reported UST removals and may represent a backfilled area The metal detector did not produce a response • over this area, indicating that the GPR anomaly does not represent a metallic object such as a UST or drum GPR data from traverses across the EMLL anomaly, located north of the former welding building (and shown in blue with diagonal shading on Plate 1), indicate that it is probably due to small near surface metallic debris