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other types of probes are similar to those conducted last <br /> year by Dames & Moore Geologist in the Alden park area in <br /> Tracy. The probe area was formerly the site of an old oil <br /> storage reservoir facility that is now occupied by a city <br /> park and residential area. Dames & Moore took soil samples <br /> from the vadose zone to depth of approximately 9 feet,using <br /> adaptable hand-operated sampling equipment. The bore holes <br /> were about one-inch in diameter and were drilled into the <br /> ground under the supervision of registered geologists. The <br /> bore holes are then back-filled with bentonite pellet$ to <br /> seal the holes off. After analyzing the soil samples, Dames. <br /> & Moore designed and recommended the means for removing the <br /> hydrocarbon laden soil by way of soil venting through <br /> portable vacuum pumps. Dames & Moore completed their survey <br /> and turned over their recommendations to Chevron oil <br /> Corporation for implementation. <br /> Here's how the system works: a three-quarter inch carbon <br /> steel pipe is advanced into the ground to depths from 3 to <br /> 7 feet below grade. At that depth a carbon steel "drive <br /> tip" is driven an additional 3 to 5 inches more to expose <br /> the lower end of the pipe. The top of the steel pipe is <br /> then plugged with a special connector (hose-barb) , attached, <br /> and then encased in a regular irrigation valve box. The <br /> hose-barb in the plugged pipe is then connected to a vacuum <br /> well/pump near the probe site. vacuum pressure is then <br /> regulated, controlled, and measured in the removal of air <br /> samples from the various buried pipes. The operation is <br /> really a circulating system whereby soil venting effectively <br /> removes oil contaminates from the vadose zone by <br /> continuously drawing air through the ground and out through <br /> the vacuum well. The theory is to evaporate the oil spill <br /> area by air circulation. The piping is subsequently removed <br /> from the site within 3 months and the bore hole is back- <br /> filled with compacted soil . <br /> since this operation does not fall into the category of a <br /> water-well , cathodic protection well, or monitoring well as <br /> defined in (SB 1817) , a (C-57) Water Well Drilling license <br /> is not required for this operation. <br /> Soil sampling and testing is exempt under Business and <br /> Professions Code "1051 whereby geologists are exempt from the <br /> license law when acting solely in their official capacity. <br /> Temporary soil venting through a pumping operation is <br /> similiar to a well point system in dewatering a <br /> construction site as the apparatus is removed when the <br /> contruction is completed. A well point system or any other <br /> type of temporary dewatering system is exempt from <br /> licensure. <br /> Other types of bore holes discussed in our January 6 meeting <br /> were geophysical borings. By way of explanation, <br /> geophysical drilling is a process of drilling holes about 3 <br />