ARCHIVED REPORTS_XR0004561 - Laserfiche WebLink

Home Browse Search

ATTACHMENT C FIELD AND LABORATORY PROCEDURES Chevron Service Station 9-1452, 334 East Main Street, Ripon, California WELL INSTALLATION ACTIVITIES Health and Safety As required by the Occupational Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910.120), and by California Occupational Health and Safety Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192), SECOR prepared a Site-Specific Health and Safety Plan for use during fieldwork. The field staff and contractors reviewed the Site-Specific Health and Safety Plan before beginning field operations at the site. Exploratory Drilling The soil borings were advanced using 8-inch hollow-stem auger drilling equipment to approximately 40 to 60 feet bgs. A SECOR representative using the Unified Soil Classifica- tion System (USCS) and standard geologic techniques logged continuous soil samples from the deep borings. Soil samples were collected continuously using a California-modified split-spoon sampler. Soil samples for chemical analysis were collected in five foot intervals below 40 feet bgs and retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in zip-lock bags. The samples were placed on ice for transport to the laboratory accompanied by chain-of-custody documentation. Down-hole drilling and sampling equipment was steam cleaned prior to and following the completion of each soil boring. Down hole sampling equipment was washed in a tri-sodium phosphate or alconox solution between samples. Groundwater Monitoring Well Installation The borings were converted to groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0.020-inch factory-slotted screen. Approxi- mately 15 feet of screen was placed in the bottom of each shallow boring and approximately five to ten feet of screen was placed in the bottom of each deep boring. A grade of sand appropriate to the screen size was placed in the annular space across the entire screened interval, and extends approximately 2 feet above the top of the screen for each well. A bentonite seal extends two feet above the sand pack. The monitoring wells were completed with neat cement from the bentonite seal to ground surface. The well casings were topped with a locking cap, and the well heads contained in watertight traffic rated, flush mounted well boxes. The boring logs show well construction details. _.. .......... .............� — _.