FIELD DOCUMENTS_CASE 1 - Laserfiche WebLink

Home Browse Search

i ENVIRONMENTAL SCIENCE & ENGINEERING, INC. CONCORD, CALIFORNIA OFFICE STANDARD OPERATING PROCEDURE NO. 1 FOR SOIL BORINGS AND SOIL SAMPLING WITH HOLLOW-STEM AUGERS IN UNCONSOLIDATED FORMATIONS Environmental Science&Engineering,Inc.(ESE)typically drills soil borings using a truck-mounted,continuous- flight, hollow-stem auger drill rig. The 'dell rig is owned and operated by a drilling company possessing a valid State of California C-57 license. The soil borings are conducted under the direct supervision and guidance of an experienced ESE geologist. The ESE geologist logs each borehole during drilling in accordance with the Unified Soil Classification System (USCS). Additionally, the ESE geologist observes and notes the soil color, relative density or stiffness, moisture content, odor (if obvious) and organic content (if present). The ESE geologist will record all observations on geologic boring logs. Soil samples are collected during drilling at a minimum of five-foot intervals by driving an 18-inch long Modified California Split-spoon sampler(sampler),'lined with new,thin-wall brass sleeves,through the center of and ahead of the hollow stem augers, thus collecting a relatively undisturbed soil sample core. The brass sleeves are typically 2-inches in diameter and 6-inches in length. The sampler is driven by dropping a 140-pound hammer 30-inches onto rods attached to the top of the sampler, Soil sample depth intervals and the number of hammer. blows required to advance the sampler each six-inch interval are recorded by the ESE geologist on geologic boring logs. The ends of one brass sleeve are covered with Teflon sheeting,then covered with plastic end caps. The end caps are sealed to the brass sleeve using duct tape. Each sample is then labeled and placed on ice in a cooler for transport under chain of custody documentation to the designated analytical laboratory. A portion of the remaining soil in the sampler is placed in either a new Ziploe* bag or a clean Mason Jar* and set in direct sunlight to enhance the volatilization of any Volatile Organic Compounds (VOCs) present in the soil. After approximately 15-minutes that sample is screened for VOCs using a photoionization detector(PID). The PID measurements will be noted on they geologic boring logs. The PID provides qualitative data for use in selecting samples for laboratory analysis. Soil samples from the saturated zone(beneath the ground-water table) are collected as described above, are riot screened with the PID, and are not submitted to the analytical laboratory. The samples from,the saturated zone'are used for descriptive purposes. Soil samples from the saturated zone may be retained as described above.for physical analyses (grain size, permeability and porosity testing). p , If the soil boring is not going to be completed as.a well,then the boring is typically terminated upon penetrating the saturated soil horizon or until a predetermined interval of soil containing no evidence of contamination is. penetrated. This predetermined interval is typically:based upon site specific regulatory or client guidelines. The boring is then backfilled using either neat cement, neat cement and bentonite powder mixture (not exceeding . 5% bentonite), bentonite pellets, or a sand and cement mixture (not exceeding a 2:1 ratio of sand to cement). However, if the boring is to be completed as a monitoring well, then the boring is continued until either a competent, low estimated-permeability, lower confining soil layer is found or 10 to 15-feet of the saturated soil horizon is penetrated,whichever occurs first. If a low estimated-permeability soil layer is found,the soil boring will be advanced approximately five-feet into that layer to evaluate its competence as a lower confining layer, prior to the termination of that boring. All soil sampling equipment is cleaned between each sample collection event using an Alconoxo detergent and tap water solution followed by a tap water rinse. Additionally, all drilling equipment and soil sampling f equipment is cleaned between borings,using a high pressure steam cleaner,to prevent cross-contamination. All wash and rinse water is collected and contained onsite in Department of Transportation approved containers (typically 55-gallon drums) pending laboratory analysis and proper disposal/recycling. a ' F