ARCHIVED REPORTS XR0006857 - Laserfiche WebLink

Home Browse Search

r six inch lengths, and the sampler is advance. The first six inches are utilized to set the sampler, and subsequent blow counts are recorded per six inch increment. The sampler is withdrawn from the augers and boring and removed for sample evaluation, screening, and containment for laboratory analysis. The rod or hammer is replaced in the hole, with a bit plug and the boring is advanced to total depth. Borehole Closure After the boring is advanced to total depth and pertinent data recorded, the hole is grouted shut in accordance with local or State of California requirements. Shallow borings may be grouted by emplacing a neat-cement/bentonite grout directly into 1 the hole. This procedure may be utilized where all of the following are evident: 1 .) the hole is open to total depth, and this is verified by weighted tape measure 2.) approval of the regulatory agency has been secured 3.) the boring is shallower than 20 feet 1 Where the above conditions are not met, grout is emplaced through the augers, or pressure pumped through a tremie pipe. Sample Collection Ii Soil samples are collected utilizing a decontaminated modified California sampler ("split-spoon"). Typical samplers contain three, two-inch LD by six-inch long brass sample sleeves. Longer samplers up to 48-inches long utilizing acrylic core barrels are available and useful in coring bedrock samples with HSA equipment. The sampler is opened at the surface and the three sleeves are removed. The bottom sleeve is sealed immediately with Teflon sheeting, capped with plastic caps, and sealed with packaging tape. A unique sample number is assigned to the sample. The sample number shall include the boring or well number, the depth, the date, a site address and the samplers initials. This information is sufficient in most cases to provide stand-alone information in sample identification and chain-of-custody. This sample is then immediately placed on ice in an iced cooler in the possession of the sampler for relinquishment to the analytical laboratory. The middle of the three sleeves, and material form the sampler nose is evaluated by the geologist for volatile soil vapors, soil classification and sieve analysis, where needed.