Laserfiche WebLink
1 <br /> Working To Restore Nature <br /> April 15, 1993 <br /> 1 ARCO Facility No 6020, Manteca, California <br /> FIELD INVESTIGATION <br /> i <br /> Field work performed at the site by RESNA on behalf of ARCO was conducted in <br /> accordance with RESNA Site Safety Plan No 30055-925 (November 10, 1992) and RESNA <br /> Work Plan No 30055-5 (November 6, 1992) <br /> i <br /> Soil Borings and_Sampling <br /> A geologist from RESNA was onsite November 18 through 21, 1992, to observe Westex <br /> Drilling of West Sacramento, California, drill six soil borings (B-8 through B-13) and <br /> construct four ground-water monitoring wells (MW-1 through MW-4) in four of the borings <br /> The soil boring locations were chosen to evaluate residual hydrocarbons in soil near the <br /> tank cavity, proposed tank cavity and dissolved hydrocarbons in ground water near the <br /> property boundaries The total depth of the soil borings ranged from 23-1/2 to 39-1/2 feet <br /> below grade <br /> Our geologist collected soil samples at 5-foot intervals for possible laboratory analyses and <br /> to evaluate the stratigraphy beneath the site Soil samples were identified using visual and <br /> manual methods and classified according to the Unified Soil CIassification System <br /> (Appendix A) Descriptions of materials encountered are presented in the Logs of Borings <br /> (Appendix A) <br /> The sediments encountered from the surface to approximately 16 feet below grade consist <br /> of sand From 16 to 29 feet below grade the sediments consist of silt with trace of clay, and <br /> from 29 feet below grade to the total depth explored sediments generally consist of sand <br /> 30055-5 <br /> 4 <br />