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1 <br /> • Soil in the next sample tube (where available) was used to describe the lithology <br /> and measure VOC concentrations Approximately half of the sample from the <br /> sample tube was removed and placed in a resealable plastic bag The plastic bag <br /> was set aside to allow VOCs, if present, to accumulate in the headspace above the <br /> sampled soil The headspace was then sampled using a portable PID The PID <br /> probe was inserted through a hole made in the plastic bag and the highest <br /> measurement encountered recorded on the boring log <br /> • Soil and wastewater generated during the field activities was contained in 55-gallon <br /> United Nations approved drums <br /> rWell Construction Procedures <br /> The monitoring wells were constructed of flush-jointed, threaded, 2-inch, <br /> Schedule 40 PVC casing The well casing was delivered to the site in factory <br /> plastic wrap The casing had rubber or Teflon O-ring gaskets at the joints <br />' • The slotted interval consists of 0 020-inch machined slots The filter pack consists <br /> of RMC Pacific 93 Sand The slot size and filter pack had been selected with the <br /> intent to minimize the amount of native lithologic and filter pack material entering <br /> the monitoring well <br /> • A bottom screw cap was placed on the bottom of the casing A 15-foot long (5-foot <br /> for MW-4RD) length of slotted casing was joined to the bottom screw cap Blank <br /> casing was used to construct the remainder of the wells <br /> C During placement of the filter pack, the well was suspended in the augers The <br /> augers were lifted 2 to 4 feet and the sand filter pack poured into the annulus The <br /> augers were then slowly lifted with sand filter pack placed "continuously" until the <br /> sand is approximately 2 feet above the top of the screen <br /> • The well was swabbed following placement of sand with a surge block Swabbing <br /> was conducted over the screened interval of the well casing, beginning at the <br /> bottom of the well Swabbing was conducted at least twice over the entire length <br /> of the well screen <br /> • An approximately 1 to 2 foot thick zone of bentonite was placed above the sand <br /> filter pack <br /> In MW-4R, an 18-foot thick zone of bentonite was placed between the sand filter <br /> pack of the deep well and the sand filter pack of the shallow well <br /> • The annulus above the bentonite was grouted with cement slurry placed by tremmie <br /> if significant water is present in the boring The cement grout should extend to a <br /> depth of approximately 1-foot bgs <br /> rj SHAW ENVIRONMENTAL,INC <br /> 41SACRFPIICOMMONISACDP120031PRJ188018800391A 3AE DOC <br /> B-2 <br />