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Work Plan for Refined Plume Definition and Management of Floating Product-7500 W 11th 5t., Tracy, C,4. Page 63 lance powered by a towed air compressor and the extracted fluid will be stored and disposed in the manner described in Sections 9.2.1 through 9.2.3. 9.4.2.4 Additional Extraction Points If observations made in the array of wells installed to investigate the lateral extent of the .. floating product present on the plume of contaminated groundwater that is described in Section 8.0 show that it would be beneficial to extract LNAPL from areas additional to those accessible via extraction wells EW-1 through EW-3, that extraction can also be done. As has .. been detailed in Section 8.1, proposed groundwater-quality monitoring wells MW-13 and MW-15 will have 6-in. diameter casings. They are both easily accessible by a vacuum truck and can be purged of floating product using the same procedures as have been described herein for extraction of LNAPL from the three wells specifically designed for that purpose. 9.4.2.5 Schedule It is estimated that it will take approximately one month from the time implementation of Technology B - Pumping of LNAPL from Extraction Wells into Vacuum Trucks - is •— authorized to complete a final design, obtain monitoring well permits from the SJCEHD, encroachment permits for installation of extraction wells in public highways from the SJCPWD and to obtain the necessary bonds for those wells. We expect the drilling contractor to be able to mobilize to the field within three weeks of the necessary permits being obtained. Installation of the extraction wells will require two days •-"'� and, after a one week delay to permit concrete and grout to set; their development will require one day. After development, the groundwater will be allowed to stabilize for at least seven days before the thickness of floating product in the wells is measured. Based on the above-stated assumptions, the first extraction of LNAPL from the wells could occur within 60 days from the date authorization to construct the system is received. The schedule for later rounds of floating product extraction will be adjusted based upon the observed rate at which floating product accumulates in the wells following its periodic removal. For reasons of economy, after the first extraction of floating product from the extraction wells is initiated, the vacuum truck will be scheduled to the site at a frequency.a& no greater than once per week. However, based on the progress of interim measures at the site (see Section 9.2.4), it is expected that, as time passes, it,will be appropriate to reduce the frequency to monthly visits in order for sufficient floating product to accumulate in the wells to justify the cost of extraction. Later, it may be appropriate to reduce the evacuation frequency to a semi-annual or annual schedule. When floating product no longer appears in the extraction wells, samples of groundwater will `W be recovered from them on the same schedule as will prevail at that time for the general groundwater-quality monitoring program in place at the 7500 West Eleventh Street Site. When a sufficient record of groundwater quality in the extraction wells has been established (which will not be less than that obtained from four quarterly rounds of groundwater-quality �-+ monitoring), that data will be evaluated and, if appropriate, the extraction wells will be SJC