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Work Plan Addendum to Install Compliance Groundwater Monitoring Wells Musco Family Olive Company Tracy California - MW-35 will be overdrilled to its full vertical extent,approximately 170 feet(ft) below ground surface (bgs).Over-drilling is a decommissioning technique used to physically remove an entire monitoring well, its sand pack and associated fill. Monitoring well MW-35 was installed using a hollow stem auger drill rig rotating 4.25-inch inner diameter,8-inch outer diameter augers.The construction details are summarized below: • A two-inch schedule 80 Polyvinyl Chloride(PVC)well casing and screen was installed to an approximate total depth of 170 feet bgs. • The screen interval was installed between approximately 150 ft bgs to 170 ft bgs with approximately 2 feet of sand installed above the screen interval(148 feet bgs to 150 feet bgs). • The bentonite seal was installed from approximately 144.5 feet bgs to approximately 148 feet bgs. • Portland cement grout seal was installed from approximately 1 foot bgs to approximately 144.5 feet bgs. A concrete surface completion was installed for a riser pipe completion. Prior to initiating the decommissioning activities,a depth to water measurement will be collected and the depth of the monitoring well will be confirmed. I The overdrilling of the monitoring well will be completed using a hollow stem auger drill rig that will rotate augers with a minimum outer diameter of 10-inches. The auger will be advanced to approximately 171 feet bgs,approximately one foot below the original bore depth.After completing the overdrilling, neat cement grout will be tremied through the hollow stem auger.The borehole will be grouted from the bottom up,as the augers are removed from the borehole.After full removal of the augers,the borehole will be topped off to account for settling of the grout. Monitoring Well MW-35R Installation Monitoring well MW-35R will be installed at the approximate location illustrated in Figure 2 using a hollow stem auger drill rig in accordance with the procedures described in the December 9, 2013 Work Plan, "Work Plan to Install Compliance Groundwater Monitoring Wells, Musco Family Olive Company, Tracy,California" ("the Well Installation Work Plan").The Central Valley Regional Water Quality Control Board(RWQCB)conditionally approved the Work Plan in a letter dated January 7,2014.A hollow stem auger drill rig was used to install MW-35 and therefore it is expected that this technology can be used for the installation of MW-35R. Monitoring Well MW-35R will be constructed as a two inch monitoring well following the specifications described in the Well Installation Work Plan. The drill bit will be advanced to first encountered groundwater and the screen interval will span the entire length of the water bearing zone,or a maximum screen length of 20 feet, unless the depth of the well is extended to 335 feet and dry conditions still are noted. In that scenario,the screen interval will be constructed in accordance with the contingency procedures discussed in the Well Installation Work Plan and provided below).After the desired depth of the borehole is reached,the auger will then be slowly removed from the borehole as the monitoring well casing,sand,bentonite, and/or grout are added from the bottom up.A threaded schedule 80,2-inch PVC groundwater monitoring well will then be constructed in accordance with the specifications provided in the Well Installation Work Plan. Terraphase Engineering Inc. Page 2 of 6