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Work Plan Page 8 Former Manna Pro Site ' Project No 207 3 August 16, 1999 ' sample is retrieved it will be analyzed by an on site mobile lab The purpose of using a mobile lab will be to determine the distribution of hydrocarbons in the groundwater as the I boring is being advanced In this way, the appropriate total depth can be established The boring will be terminated at the point where the first groundwater sample is obtained which does not contain detectable levels of gasoline range Total Petroleum Hydrocarbons ' as Gasoline (TPH-G) or BTEX compounds The monitoring well, MWD-11, will be constructed using blank 2" Schedule 40 PVC ' casing extending from ground surface to approximately 5 feet above the base of the boring (estimated total depth between 60 and 120 feet below grade) The well screen will consist of 0 010" slotted 2" diameter schedule 40 PVC casing extending from the total depth to 5 feet above the total depth The filter pack will consist of#3 Monterey Sand extending from the total depth of the boring to ±10 feet above the total depth of the boring Approximately 4 feet of bentonite chips will extend from above the top of the filter pack From that point, to grade, the boring will be backfilled with cement grout A water tight locking J plug will be used to cap the casing and insure that surface water does not infiltrate into the well Finally, a traffic rated well box will be installed over the top of the well 3.4 Monitoring Well Development After the well sealing materials have set for at least 48 hours the MWD-11 well will be developed (using mechanical surging and pumping, or balling methods) until a clear stream of water is generated All development water will be containerized in 55 gallon DOT approved containers and stored on site until its disposal can be arranged At least 24 hours after development, the well will sampled using methods and protocols described below to Section 6 2 2 It is proposed that groundwater samples initially be collected from select wells on a quarterly basis for a period of one year and depth to water measurements be made from all of the wells on a monthly bans 3.5 Well Survey Upon construction, all new wells will be surveyed by a licensed surveyor to assure that the vertical and lateral position of the wells is accurately known, and that they are tied to a nearby bench mark The existing monitoring wells have never been tied to a bench mark, and moreover, inspection of the existing site map in comparison to what is on the 2937 Veneman Ave ,#B240 Geo-Phase Environmental Inc Phone(209) 569-0293 Modesto, CA 95356 Fax(209) 569-0295