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GeoHydrologic Consultants, Inc The results are summarized in Table 2A with historic groundwater sample results and the ' sample results from the first quarter 2005 The results for the additional oxygenate data are summarized in Table 213 The laboratory reports and chain-of-custody documentation for these samples are included in Appendices E and F The distribution of the TPHg, benzene, and MTBE concentrations in groundwater is depicted in Figure 5A, 5B, and 5C, respectively 4.6 Well Development West Hazmat Drilling was contracted to develop eight existing on-site wells and the two ' newly installed wells (EW-5D and EW-5S) Development of the ten on-site wells was conducted on February 23 and 24, 2005 A stainless steel bailer was used to purge groundwater and remove silt from the wells which was operated by a cable winch using a ' truck-mounted development rig Depth to water and depth to bottom (both prior to and post development) were gauged and the purge water was stored on-site in DOT approved 55-gallon containers Wells EW-5D and EW-5S were developed by surging and bailing on Thursday February 24, 2005 Information concerning the well development is included in Table 3 ' 5.0 MULTI-PHASE EXTRACTION PILOT TESTS lie To determine the effectiveness of multi-phase extraction (combined vapor/groundwater extraction) and the proper spacing of wells for multi-phase extraction activities if this technology is selected as the remedial solution for the Site, a two-day pilot study was conducted on March 17 and 24, 2005 The tests consisted of two 8-hour multi-phase (vapor/groundwater) extraction pilot tests performed on extraction wells EW-5D and EW-5S on March 17 and March 24, respectively The results are summarized in the following subsections The MPE tests were conducted using a mobile vapor extraction test rig, supplied by TRC ' Alton Geoscience (TRC) of Irvine, California and a two-inch diameter variable speed Grunfos electrical submersible pump for extraction of liquids Liquids were discharged through a new garden house to a 4,000-gallon Baker Tank which was stored onsite ' pending analytical results and for proper disposal of purged groundwater The vapor extraction test rig had a flow rate capability of 313 actual cubic feet per minute ' (acfm at 60° F and 14 7 psi ) and total vacuum capable of 394 inches of water or up to 29 inches of mercury (in Hg) The test rig was equipped with a liquid knockout pot having an automatic transfer pump, manual and automatic dilution air control, a high-vacuum blower(powered by a separate mobile generator), and a propane fired thermal oxidizer for destruction of extracted vapors The tests were performed at maximum flow rates to arrive at a better understanding of airflow characteristics, radius of influence (ROI), ' effect of the vacuum on the water table, and changes in concentration at each well • ' roc 171 Not study Page 9