WORK PLANS - Laserfiche WebLink

Home Browse Search

Stattbec Well Deatmdlon Work Plan Stockton Charter Way Commingled Plume August 12, 2011 until 15 to 30 minutes after pumping. An electric airless paint sprayer will be used to allow a more controlled grout pumping rate. The electric sprayer could provide a flow rate of up to 0.5 gallons per minute (gpm) or about two liters per minute (L/min) with pressures adequate for grouting. The grout volume will be monitored during the grouting process to ensure that the grout has completely filled the channels. The three channels screened from 70 to 80 ft bgs (SMW-18-80) has an approximate total volume of 9,600 milliliters (mL) [40 ni multiplied by 80 ft long channel multiplied by three channels] or 2.54 gallons and the void space in the sand pack interval has an approximate total volume of 4.01 cubic foot (cu-ft) [0.79 cu-ft/ft multiplied by 17 ft long sand pack multiplied by 0.30 estimated porosity] or 30.0 gallons. CMT well SMW-18-80 will require approximately 32.54 gallons of grout. Applying the same considerations, CMT well SMW-18-120 will require approximately 28.62 gallons of grout (smaller volume required than SMW-18-80 due to shorter sand pack interval). It is not anticipated to lose grout through the subsurface surrounding the sand packs of both SMW-18-80 and SMW-18-120, which consists of sandy and clayey silts. If grout is pumped beyond the sand pack annulus (anticipated total grout volume is inadequate to fill channels and sand pack), the grout viscosity will be increased. If groundwater is expelled during the grouting process, it will be properly contained, characterized, and disposed. As suggested by the manufacturer, the quarter-inch diameter tubing will be left in place for each channel to avoid creating void space if the tubing was removed. After grouting the channels, a six-inch diameter borehole will be excavated around the CMT well casing to a depth of five ft bgs. The CMT well casing will be cut off and removed at five ft bgs. Additional grout will be added over the top of cut CMT well casing to form a mushroom grout cap/surface seal at five ft bgs. The borehole will be backfilled with engineering fill and resurfaced to match the existing grade. 3.6 Waste Disposal Soil cuttings, drilling fluids, and personal protective equipment (PPE) generated during drilling operations will be containerized in Department of Transportation (DOT)-approved 55-gallon drums and temporarily stored on the subject property pending characterization and disposal. Upon characterization, wastes will be transported by a disposal contractor to an appropriate disposal or treatment facility. 4.0 REPORTING Upon completion of the proposed scope of work, Stantec will prepare a report summarizing field activities and analytical results of the well destruction activities. The report will be submitted to ARCO, Chevron, Shell, Sara Lee, and the CRWQCB-CVR and will include tabulated field data, figures, appendices containing laboratory reports, copies of field notes, and conclusions and recommendations. Also per Assembly Bill 2886 requirements, Stantec will electronically upload the data obtained into the Regional Water Quality Control Board GeoTracker database. Stockton Charter Way Commingled Plume Well Destruction Work Plan.doc 5