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. A Cambria geologist supervised the drilling and described encountered soils using the Unified Soil Classification System and Munsell Color chart Encountered lithology 2s described on the exploratory boring logs presented in Appendix B Soil samples were collected for lrthologic description and chemical analysis from the borings at five- foot intervals during the first and third phases of drilling Soil samples selected for laboratory analysis were collected in brass tubes, covered with Teflon tape, capped, labeled, entered onto a Chain-of-Custody record, and stored in a cooler with ice The samples were transported to Sequoia Analytical (Sequoia) of Redwood City, California for analysis The soil samples were analyzed for Total Purgeable Petroleum Hydrocarbons (TPPH) according to EPA Method 8015 (Modified), and benzene, toluene, ethylbenzene, xylenes (BTEX), and methyl- tert►ary-butyl-ether according to EPA Method 8020 Soil Stockpile Soil and drilling mud generated during drilling activities were contained in bins Soil samples were collected from the bins and analyzed for TPPH, BTEX, and TTLC Iead The soil has been profiled to Forward Landfill in Manteca, California and was transported to the landfill in early February 1998 Conductor Casing Installation- The pilot holes were reamed out with a 17 5-inch diameter mud- rotary bit to predetermined depths based on the lithologic information from the CTA borings After reaming was completed, 12-inch diameter steel conductor casing was installed in the boring Centralizers welded onto the outside of the conductor casing were utilized to center the conductor in the bore hole After placing the conductor casing in the boring, it was then pushed 1 to 2 feet into native soil at the bottom of the boring The annulus between the boring and the conductor casing was sealed with cement grout The conductor casings were set at the following depths MW-12 was set at 56 fbg, MW-13 was set at 55 fbg, and MW-14 was set at 50 fbg Monitoring Well Installations Drilling inside of the conductor casings was performed with 10-inch diameter hollow stem auger drilling equipment to final depths of 86 5, 80 5, and 80 fbg, respectively Well screen was placed in MW-12 from 69 to 84 fbg MW-13 was screened from 68 to 78 fbg, and MW-14 was screened from 69 to 79 fbg All three wells were constructed of 4-inch diameter, threaded, Schedule 40 PVC well casing and 0 020-inch slot well screen Well construction included the placement of filter pack sand across the screened interval extending three feet above the top of the screened interval A two foot thick bentonite seal was placed above the sandpack followed by a cement-grout seal to grade Each well was secured with a locking well plug and a vault box Well completion details are presented in Table 1 and on the exploratory boring logs contained in Appendix B 240-0783 13