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ri <br /> w� <br /> Harding Lawson Associates <br /> 4 HLA obtained well installation permits from the SJLHD on November 20, 1986. <br /> Four borings were drilled to depths between 20 and 26 feet, with drilling <br /> completed on November 24, 1986. The boring locations are as shown an Plate <br /> 1. Each boring was sampled at 5-foot intervals using a 2.5-inch-diameter <br /> Sprague & Henwood (S&H) sampler, Samples were retained in brass tubes' <br /> 6 inches long, sealed on either end with aluminum foil and tape. Plastic caps <br /> i <br /> w were then placed over the ends, and the samples were placed in a cooled ice <br /> 7 ,aJ <br /> chest. All sampling equipment was thoroughly cleaned in a solution of tri- <br /> s <br /> sodium phosphate and tap water, then rinser in distilled water' before and <br /> E after each sampling. Augers were steam cleaned prior to use and between <br /> ` borings in order to avoid crass-contamination between wells, All cuttings <br /> t <br /> g <br /> ii from drilling operations were stored in 55-gallon drums and left on site: <br /> F <br /> Detailed descriptions of the materials encountered in the.h:lrings are <br /> presented on the Logs of Borings, Plates 3 through 6. These Zags include the, <br /> blow counts of the S&H samplers, converted to Standard Penetration blow counts <br /> (N-values*). The soil materials are described in accordance with the Unified <br /> Sail Classification System shown on Plate 7. The samples were logged by our <br /> field.engineer and then turned over to Analytical Science Associates <br /> (ASA) in <br /> Emeryville, Ca' :fornia for chemical testing. i <br /> i <br /> Up an completion of drilling and sampling,.we installed 2-inch-diameter <br /> - Schedule 40 PVC well casing_;.r._near the bottom of-each-borehole. Well <br /> Standard penetration' N-values are defined as the number of blows of a i <br /> 140-pound hammer falling 30 inches required to advance a standard sampler <br /> IF 1 <br /> (2 inches O.D.` and 1.5 inches 1.D,)` the final 12 inches of an 18=inch <br /> f drive. The standard-hammer driving mechanism utilizes a cathead-drum and a <br /> " rope and pulley system. <br /> 6 <br /> '.t <br />