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Workplan for Interim Remediation&4`h Quarter 2000 Groundwater Monitoring Report k-6.01 Former Moore Petroleum Bulk Plant,549I F Street,Banta,California Page 3 of 9 PROPOSED REMEDIATION WELL INSTALLATIONS Apex proposes to drill four soil borings and convert three of the four borings into six inch diameter groundwater remediation wells RW-1, RW-2 and RW-3, (Figure 4). The fourth boring, (VEW-2) will be converted into a four inch diameter vapor extraction well. The three proposed. soil borings (RW-1, RW-2 and RW-3) will be drilled to an anticipated total depth of 30 feet below grade (bg) with the use of a hollow stem auger drill rig. The fourth boring (VEW-2) will be drilled to an anticipated total depth of 20 feet bg. Soil samples will be collected at five-foot intervals, obvious lithologic changes, or obvious hydrocarbon odors from each of the borings. All fieldwork will be conducted according to the Apex SOP included in Appendix B. MONITORING WELL CONVERSION .The one existing four inch diameter groundwater monitoring (MW-8)has a four inch conduit and daylights inside the vault box already. This four inch conduit runs from MW-8 to the back of the warehouse (Figure 4). This conduit was installed during the removal and excavation of the two former USTs located east of the office. Groundwater monitoring well MW-8 will also be referred as VEW-1. BORING AND WELL CONSTRUCTION REQUIREMENTS Prior to drilling, well permits will be obtained from the County and Underground Service Alert (USA) will be contacted for identification of buried utilities at or entering the project site from the public right-of-way. As.a further precaution against drilling into or through potential buried obstructions, the first five feet of each boring will be augured by hand. At a minimum, the wells will be constructed according to the standards found in the California Code of Regulations, Title 23, Section 2647 and 2648 and the California Department of Water Resources Bulletins 74-81 and 74-90. The four proposed wells will also be constructed according to the Apex SOP included in Appendix B and include 0.020-inch perforated casing. The filter pack will be placed from 2 feet above the screen interval to total depth. The bentonite seal will be placed from 2 to 4 feetabove the screen interval and a cement/bentonite slurry will be placed from near surface to 4 feet above the screen interval. The wells will be secured with a Q� Q locking, watertight cap. C �