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CA ARNG Field Quality Assurance Project Plan may be lost. Hand augers equipped with 3 -inch diameter cylindrical stainless steel bits are used. Backfill hole with native material, or fill hole with cement grout, if required in the work plan or scope of work. 9.1.3 Subsurface Soil Sample Collection Procedures 9.1.3.1 For subsurface soil sampling, soil samples may be collected continuously from 6 inches to 10 feet bgs. Additional samples may be collected at 5 -foot intervals, or at a change in lithology, whichever is less, until groundwater is first encountered. Additional samples may be collected from the depth where groundwater is encountered to the borehole total depth (continuous coring may be required for some efforts). Depending on site-specific considerations, the soil samples collected may be used for lithologic description, archiving for later description, field screening for potential contamination, chemical analysis, and/or geotechnical analysis. The soil samples will be logged in the field by a qualified geologist/ hydrogeologist supervising the drilling. All samples will be described in accordance with the Unified Soil Classification System (USCS). Sample descriptions will be approved by the California Registered Geologist who supervised the rig geologist. Samples will be stored in labeled, air -tight plastic containers or stainless steel sleeves until they are needed for testing. Laboratory analyses will use equipment and methods described in EM -1110-2-1906 or ASTM manuals. Sample Collection During Drilling 9.1.3.2 To collect soil samples using the hollow -stem auger (HSA) drilling method, the pilot bit is removed and, if necessary, the inside of the hollow stem is cleaned out. Soil samples will be obtained by lowering a split -spoon sampler, fitted with stainless steel sleeves attached to the drill rods or wire -line to the bottom of the borehole. The split -spoon sampler will be driven into the undisturbed formation with a 140 -pound hammer repeatedly dropped from a height of approximately 30 inches. The number of times required for the hammer to drop to collect 6 inches of sample will be recorded to provide qualitative information regarding the density of the- material -encountered. The nominal -size- of the sample will be either 1.5 or 2.5 inches ID, 18 inches in length, and manufactured of stainless steel. 9.1.3.3 To collect soil core using the ARCH drilling method, the rotary drill is withdrawn, the outer casing is cleaned out, and a split -spoon sampler fitted with stainless-steel sleeves attached to the drill rods or wire -line is lowered to the bottom of the borehole. As with the HSA method, the split -spoon sampler will be driven into the undisturbed formation with a 140 -pound hammer repeatedly dropped from the height of approximately 30 inches. The number of times required for the hammer to drop to collect 6 inches of sample will be recorded to provide qualitative information regarding the density of the material encountered. The nominal size of the sampler will be either 1.5 or 2.5 inches ID, 18 inches in length, and manufactured out of stainless steel. 9.1.3.4 Three 6 -inch long stainless steel liners will be used inside the split -spoon samplers. Upon sample retrieval, the split -spoon sampler will be opened, soil materials will be inspected and lithologically logged, and plastic caps with Teflon® liners will be secured to each end of the stainless steel liners to be used for chemical analysis. Samples to be collected for volatile analysis may be collected using an Encore® sampling container or other specified collection procedure (Method SW5035). Only soils from the top liner, the leading end of the split -spoon, will be logged. The bottom and middle liners are designated for chemical and geotechnical analyses and will not be disturbed. Additional liners will be collected to provide sufficient sample quantity to provide duplicate and split soil samples. All sampling equipment will be decontaminated prior to each use. field QAPP.DOC 9-2 May 2000