WORK PLANS - Laserfiche WebLink

Home Browse Search

0 28 August 2017 AdvancedGeo AGE Project No. 14-3096 Environmental Page 6 of 7 0 M"EM Grab groundwater samples will be collected from soil boring P-16 in the following water bearing zones: Zone A at approximately 30 feet bsg, Zone B at approximately 60 feet bsg, Zone C at approximately 90 feet bsg, and Zone D at approximately 115 feet bsg. Grab groundwater samples will be collected from soil boring MW-14 in the following water bearing zones: Zone A at approximately 30 feet bsg and Zone C at approximately 90 feet bsg. Grab groundwater samples will be collected using a HydroPunchTm sampling assembly loaded with a four-foot temporary perforated well screen. Each groundwater sample will be extracted by dedicated disposable polyethylene tubing through the hollow center of the push rods into the screen section. Following sample collection, samples will be transferred into four volatile organic analysis (VOAs) vials; all samples will be properly labeled and placed in a chilled container to be transported under chain of custody to a CDPH-certified laboratory for analysis of constituents listed in Section 2.5. 3.3. WELL COMPLETION AND ELEVATION SURVEY Upon backfilling with bentonite pellets to a depth of approximately 65 feet bsg, the soil boring (MW-14) will be single-completed as a groundwater monitoring well utilizing a 2- inch diameter, Schedule 40 PVC blank well casing and 0.010-inch slotted well screen installed from 50 feet to 65 feet bsg. A diagram of the proposed monitoring well construction is depicted in Figure 8. After installing the well casing in the soil boring, a filter pack material consisting of pre- washed #3 or a 2/12 Lonestar sand will be added through the augers from total depth to approximately 2 feet above the screened interval. Following placement of the filter pack, the well will be surged to assist in settling the filter pack. Additional sand will be added if settling occurs. A three-foot bentonite seal (i.e. bentonite pellets) will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the wells. The bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack. The bentonite pellets will be allowed to hydrate for the duration of time specified by the manufacture (i.e. 30 minutes), prior to grouting. The remaining annular space will be filled to within one foot of the ground surface with a cement grout. The grout mixture will consist of Type 1/11 Portland neat cement and not more than 3 gallons of water per 50-pound sack of cement. The grout will be placed by pouring or pumping through a tremie pipe or auger. A grouting inspection will be scheduled with San Joaquin County EHD personnel prior to any application of grout.