ARCHIVED REPORTS_XR0003170 - Laserfiche WebLink

Home Browse Search

A �r borings EB-4 , EB-5, and EB-6 (at 4 . 1 to 5. 3 ppb) , however, these ' may be "background" levels virtually unrelated to the fuel hydrocarbons present. ' RECOMMENDATIONS In consideration of the data acquired to date, Uriah proposes ' to advance five additional soil borings, each to a depth of 60 feet bgs. The placement of these borings is expected to complete the definition of the horizontal and vertical extent of contamination. Three of the borings will be extended to ' 70 feet bgs and converted to 2-inch diameter groundwater monitoring wells. Locations of the proposed borings are presented in Figure 2 . ' All soil borings will be advanced using 8--inch outside-diameter hollow-stem augers. The borings will be continuously logged ' using the Unified Soil Classification system and soil samples will be collected, preserved, transported, and analyzed as described above (with the exception of lead which may be deleted from the sampling regimen per DHS/EHD) . Additional soil samples ' may be collected at significant changes in lithology exposed in the three-inch diameter continuous core by driving one of the 6-inch brass tubes into the core by hand until the tube is completely filled, and then sealing and handling the sample tube as described above. ' Before sampling and coring, and between sampling and 5-foot continuous core intervals, the sampler and core barrel will be thoroughly scrubbed with Alconox solution, rinsed with tap water, and then rinsed again with distilled water. Augers will ' be steam cleaned prior to being brought on site and between borings. ' All borings in which monitoring wells will be installed will be advanced to a depth of 70 feet, or 10 feet past the deepest perceptible soil contamination. Wells will be screened from 70 feet to 50 feet bgs. If continuous coring shows no permeable beds between 70 and 65 feet bgs, the bottom 4 feet of the boring well be backfilled with Monterey Sand or neat cement, and the well will be constructed to a depth of 65 feet bgs, with the ' screened interval extending from 65 feet bgs to 45-50 feet bgs, except in those areas where the screened interval may be extended to permit the well to be fitted with packers and utilized for the extraction of hydrocarbon vapors during the remediation phase of this project. All wells will be 2-inch inside diameter unless stated otherwise. The annulus between the well casing and the edge of the boring will be filled with #2/12 Washed Monterey Sand to a depth of 49 feet bgs, sealed with '--inch pelletized bentonite hydrated with distilled water from 49 feet 5.