ARCHIVED REPORTS XR0012752 - Laserfiche WebLink

Home Browse Search

i PA i 1 r APPENDIX A - 3 r Il\1VESTIGATIVE PROCEDURES i' Exploratory Soil Boring and Monitoring Well Installation The soil borings were drilled using hollow-stem auger drilling equipment, and logged by a PACIFIC geologist using the Unified Soil Classification System and standard geologic ; w techniques. Soil samples for logging and chemical analysis were collected ata maximum depth interval of 7-1/2 feet by advancing a California modified split-spoon sampler with brass sample liners into undisturbed soil beyond the tip of the auger. The ~- sampler was driven a maximum of 13 inches using a 140-pound hammer with a 30-inch drop. Soil samples for chemical analysis were retained in the brass liners, capped with i s � aluminum foil and plastic end.caps, and sealed in clean glass jars. The samples were placed on ice and transported to the laboratory accompanied by the appropriate chain- of-custody documentation. The drilling equipment was steam-cleaned after each boring. j Selected borings were converted to groundwater monitoring wells by the installation of l 3-inch diameter flush-threaded Schedule 40 PVC casing with 0.020-inch factory-slotted t screen. Graded 12x20 sand pack was placed in the annular space across the screened f interval, and the wells were surge-blocked to remove void spaces in the sand pack. A bentonite and concrete seal was placed from the top of the sand pack to the ground 1. ' surface. A Iocking cap and protective vault box were installed on the top of each well. s Well elevations were surveyed by a licensed surveyor to an accuracy of 0.01 foot, relative to the USGS mean sea level datura. i Organic Vapor Analysis Soil samples collected during drilling were analyzed in the field for ionizable organic compounds using the HNU Model PI-101 photo-ionization detector with a 10.2 eV t ring approximately 30 grams from an " lamp. The test procedure involves measu ¥ undisturbed soil sample, placing this sub-sample in a clean glass jar, and sealing the jar r ---— - ----- ------ ---- -- -------- - ---------- with aluminum foil secured under aring-type threaded-lid.. -lid. Jar is warmed-for -- 1.-F approximately 20 minutes, then the foil is pierced and the head-space within the jar is r .. 310010,REPORT:' A- 1 September 30,1991 E s