Laserfiche WebLink
r. August 6, 1991 <br /> ARCO Station No. 548 <br /> rt <br /> Locations of the proposed soil borings,vadose wells,and monitoring wells are shown on the <br /> proposed Soil Boring Location Map (Plate 4). The soil-boring locations were chosen to <br /> f <br /> s in the soil near the existing underground gasoline storage tanks and <br /> evaluate hydrocarbon <br /> waste-oil tank, near the dispenser islands, and near the property boundaries to evaluate <br /> whether hydrocarbons have migrated offsite. <br /> drill rig equipped with 8-inch- . <br /> Soil borings will be drilled with a CME-55 (or similar) g <br /> diameter, hollow-stem augers; borings will be reamed with 10-inch-diameter hollow-stem <br /> ll <br /> team- <br /> augers for monitoring-well installation, Auger flights and sampling equipment <br /> ' brQor csshole <br /> cleaned before use in each borehole to minimize the possibility of downhole <br /> and <br /> contamination. Drilling will be performed under the observation of a field geoloa�'St'stem <br /> the earth materials in the borings will be logged using the Unified Soil Classtficatiy <br /> as drilling progresses. The soil borings that will be converted to monitoring wells ill be <br /> to <br /> drilled to approximately 1Q feet below the first encountered ground water level or 5 feet <br /> any competent clay first water bearing zone. If <br /> layer (aquitard) encountered beneath the <br /> an aquitard is encountered, the boring will be terminated and backfilled to the top of the <br /> aquitard with bentonite before insialiing a groundwater monitoring well. <br /> During drilling of the first soil boring, soil samples will be collected every 5 iotaltdoethh <br /> upper water-bearing zone and every 2-1/2 feet m the water-bearing zone to the P <br /> of the boring to evaluate subsurface sediments and the extent and thickness of the upper <br /> water bearing zone. In the remaining borings, soil samples will be collewater surfa e{ <br /> intervals, obvious changes in soil stratigraphy, and just above the ground <br /> with <br /> Samples will be collected with a California-modified, split-spoon sampler eq ipu t above <br />° ± clean brass sleeves. Samples will be collected by advancing the auger to a pointJ <br /> the sampling depth and driving the sampler into the undisturbed soil. The sampler will be <br /> u <br /> 8 <br /> AGS 30004-4 <br />