ARCHIVED REPORTS XR0000041 - Laserfiche WebLink

Home Browse Search

. Mitchell Drilling installed filter packs of Monterey#3 graded and washed sand within the annular ' spaces between the well screens and boreholes, and two feet above the tops of the screened intervals (i e , 43 feet bgs) The driller surged and purged the wells, following the placement of the sand packs and prior to the installation of the well seals Periodic surging and purging continued ' until the amount of suspended sediment in the groundwater decreased and stabilized and/or until at least five well volumes had been removed Overlying the sand packs, Mitchell Drilling placed two-foot layers of hydrated bentonite s chi Y p within the annular spaces between the boreholes and the well casings Over the hydrated bentonite, surface seals of neat cement grout were installed The tops of the wells were secured with watertight caps and traffic-rated, flush-mount street boxes ' On December 13, 2002, Morrow Surveying (Land Surveyor License#5161) surveyed the newly- installed ewt -installed wellheads Morrow Surveying located the wells and other site features, and measured the elevations of the tops of the well casings to the nearest 0 01-foot, referenced to N G S Benchmark#H-745 The surveyor's report is included as Appendix B ' 2 2 2 Soil Sampling and Analysis '. During the drilling, undisturbed soil samples were collected at 5-foot intervals using a modified California split-spoon sampler lined with two-inch diameter by six-inch long stainless steel sample ' sleeves A Ramage Environmental geologist logged each of the undisturbed soil samples for hydrogeologic and lithologic characteristics according to the Unified Soil Classification System and screened each sample for organic vapors using a photoionization detector (PID) Based on field observation, and in consultation with the EHD inspector, a total of 15 soil samples ' were submitted for laboratory analysis Each sod sample was sealed with Teflon®film and plastic end caps, and transported in an iced cooler with chain-of-custody documentation to Excelchem ' Environmental Labs (Excelchem), a state of California-certified hazardous waste testing laboratory (Certification #2119) Excelchem analyzed each of the soil samples for Total Petroleum Hydrocarbons (TPH)-as het fuel, TPH-as-gasoline and benzene, toluene, ethylbenzene, ' xylenes (BTEX) by EPA Method 8020/8015M, and for methyl tertiary butyl ether (MTBE), di- isopropyl ether (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), and tertiary butanol (TBA) by EPA Method 8260B 1 8 1'