ARCHIVED REPORTS XR0000558 - Laserfiche WebLink

Home Browse Search

S E C O R FIELD AND LABORATORY PROCEDURES Health and Safety SECOR prepared a Site-Specific Health and Safety Plan 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). The Site-Specific Health and Safety Plan was reviewed by field staff and contractors before beginning field operations at the site. CPT Borings and Groundwater Sampling The CPT method consists of advancing a cone-tipped cylindrical probe (1.7 inches-in-diameter) into the ground while simultaneously measuring resistance to the penetration. The CPT method determines soil lithology by comparing the force (cone bearing pressure) required to advance the probe (Qt) to the friction ration (Rf). The Rf equals sleeve friction [Fs] divided by the probe tip load, times the penetration pore pressure [Ud]. Computer generated CPT logs were plotted in the field that provide a graphical log of subsurface soil lithology. A CPT test data report, which includes logs of all CPT technique, is submitted with the final report. CPT testing is performed in accordance with American Society of Testing and Materials (ASTM) Method D 5778-95 (Reapproved 2000). The CPT was performed inside a grout collar installed at the ground surface. The grout collar allows the CPT contractor to backfill the borings as the steel rods are retracted from the hole. Continuous grouting prevents cross-contamination of water bearing zones that can occur through an open . borehole. The borings were backfilled to surface grade. Grout mix used to backfill the borings was Portland cement with 5% bentonite. A concrete or asphalt patch was placed over the boreholes where applicable. Immediately adjacent to the CPT boreholes a second direct push borehole was advanced to collect discrete groundwater samples. Groundwater samples were collected using a hydropunchTm or similar technology by lowering a stainless steel or Teflon® bailer into accumulated groundwater in the borehole, then retrieving and transferring the water into laboratory supplied containers. Exploratory Drilling and Soil Sampling The soil borings were drilled using either 8-inch or 10-inch hollow-stem auger drilling equipment. Borings were logged by a SECOR representative using the Unified Soil Classification System and standard geologic techniques. Soil samples for logging were collected continuously from approximately 10 feet bgs to the bottom of each boring using CME Continuous-Core System with a 2.5-inch-inside diameter core barrel. All soil samples for chemical analysis were retained in brass, stainless steel, or plastic liners, capped with Teflon squares and plastic end caps, and sealed in zip- lock bags. Discrete groundwater samples were collected in selected intervals based on stratigraphy and field analytical data. The samples were placed on ice for transport to the laboratory accompanied by chain-of-custody documentation. All down-hole drilling and sampling equipment was steam- cleaned following the completion of the soil boring. Down-hole sampling equipment was washed in a tri-sodium phosphate or alconox solution between samples. Well Completion The borings were converted to groundwater monitoring wells by installing 2-inch diameter (MW-14, MW-16, MW-17), and 4-inch diameter (MW-15, MW-15D), flush-threaded, Schedule 40 PVC casing with 0.010-inch factory-slotted screen. The screen intervals were installed in each well as described in the proposed scope of work section of the work plan. An RMC ##2116 sand pack, or equivalent, was