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o <br /> 2. PROPOSED WORK <br /> EA has been contracted by Exxon to install groundwater monitoring <br /> wells near those wells that no longer contain sufficient water to <br /> sample. EA will collect soil samples from the borings for these <br /> wells and will continue to conduct quarterly water sampling at <br /> the site atter the wells have been installed and developed. <br /> EVAX has been contracted by Exxon to undertake a soil venting <br /> i ? remedial program at the site. EA understands that permitting and <br /> 9 <br /> reporting on the construction of the system will be handled <br /> separately by EVAX. <br /> � � l <br /> i 2. 1 INSTALLATION OF THREE GROUNDWATER MONITORING WELLS <br /> EA° w.i,11 dr.i` 1 andt...:sAmple .three,;so i1 borings and'install' three <br /> groundwater monitoring:,:rrells;_(MW6,::MW7;::'MWB )_.in::.the=borin"g"s. The <br /> wells will be located adjacent to the dry wells, MW3, MW4, and <br /> MW5, as shown in Figure B. The boring logs for these wells indi- <br /> t",�..� cate that wells MW4 and MWS were terminated in a unit described <br /> as clay or sandy clay (Figure 3 ) . MW3 was terminated in a unit ; <br /> described as fine sand (see boring logs, Appendix A) . The three <br /> , i <br /> t new wells will be screened from. 50 to 75 feet below ground level i <br /> so that they contain a 15-foot water column and approximately 10 <br /> feet of screen above the depth to water. This screened interval <br /> should allow for .effective sample collection with fluctuating <br /> groundwater levels during the foreseeable life of the monitoring . <br /> r wells. <br /> The wells will be constructed with 4--inch diameter Schedule 40, <br /> -flush-threaded PVC. The":well z screen` used Vill' be :0.01.0-inch <br /> 4 . factory-slotted PVC': The'_.well screen`'wil'l' be packed in'42/i 6' <br /> Lonestar- sand-� (or equivalent) to 1.-2 feet above the tap of the <br /> screen. A 1--2 foot thick Bentonite plug will be placed on top of <br /> the sand pack, and the remainder of the annular space will be <br /> backfilled to the surface with a neat cement grout mix. The <br /> e42/71050/7-90/tx 7 <br />