ARCHIVED REPORTS_XR0004599 - Laserfiche WebLink

Home Browse Search

1 CGeological r'ecknics lna Page 3 Dual Phase Extraction Pilot Test Report Project No 662 2 February 22,2005 below grade surface (bgs) [see Figures 2 Site Map & 3 Cross Section B —B'] Sand layers at a depth of 38 —48 feet beneath the former excavation act as a preferential pathway for the MTBE plume to migrate eastward In order to further define the extent of the MTBE plume, GTI proposed installing two additional monitoring wells (MW-5 & MW-6) with screened intervals that intercept the depth of the submerged plume ' 2.3 Soil Borings Prior to commencing work, a soil boringlmomtoring well permit was secured and the SICIEHD was notified at least 48 hours in advance The subsurface was cleared of underground utilities by notifying Underground Service Alert On October 26 & 27 V&W Drilling of Isleton, California mobilized to the site to 2004 install new monitoring wells MW-5 & MW-6 The locations of the wells were determined in the field based on proximity to CPT-7 and the location of overhead and underground utilities or alleysldnveways The borings were drilled using an 8.00-inch outside diameter continuous flight hollow stern auger Soil cuttings and drilling decontamination water were placed in DOT-17 approved 55 gallon drums and retained at the site until their disposal can be arranged 2.2 Soil Sampling Soil samples were collected for geological evaluation at 5-foot intervals in the borings A boring log providing sediment description using the Uniform Soil Classification System (USCS) and field observations was completed by GTI geologists working under the supervision of Mr Ray Kablanow, a Professional Geologist All soil samples were sealed with Teflon sheets, capped with plastic end caps, labeled and placed into a cooler at 4° Celsius for transport to the laboratory following Chain of Custody protocol Soil samples were collected using a 2 0 inch modified California split spoon sampler The following information was noted during borehole logging • Sediment type, including grain size, clay content and color • Moisture content • Visible evidence of contamination, i e , color change due to reduction of iron or discoloration from hydrocarbons and other pollutants • OVM(Organic Vapor Meter) readings Details on the geology encountered during the completion of the boreholes as well as the field observations of contamination are included in Section 5 3, Geology and Contaminant Distribution MW-5 & MW-6 The subsurface details in the borings are shown on the boring log included in Appendix B