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".,�'��_- .�- �� �'���3,-s. �� ��„ � '� - e�� `��`-�''`_'ter�z � �.._��-�,-�=ir.:� _ .. � .__ A..:-�` �= `��'.�-� �r •.e,�e�; -.4�"-a' a-r.::�sS.dFII� <br /> *� � w"a"r"o r �Syn+.<� '��..� ` '. A,�.,,.' ' '',Af' ��•$�s�. � �'i+k�x ��� ^.,.Mw- ,�:..,�., ���^.-t� r � 'P, _ J �^� <br /> F <br /> May 17, 1991 <br /> rvice Station No. 2168. Stockton, California AGS 31009r into the soil through the hollow center of the auger. The sampler will be driven <br /> with a standard 140-pound hammer dropped 30 ;;riches. The number of blows <br /> required to drive the sampler each successive 6-inch interval will be counted and recorded <br /> on the held boring log to give an indication: of soil consistency. Soil samples will be <br /> collected,identifi,14 and evaluated for relative levels of gasoline hydrocarbons using a PID <br /> `s when appropriate. Examples of the Field Boring Log, the Unified Soil Classification <br /> System, and Log or Boring are included in Appendix C to this work plan. <br /> samples collected for ossible chemical analysis will be promptly sealed with aluminum <br /> 1 4 <br /> foil, plastic caps, and tape. ey will then be labeled and placed in iced storage for <br /> transport to the analytics laboratory. A Chain of Custody Record will be initiated by the <br /> field geologist and will accompany the soil samples to the laboratory. An example of the <br /> Chain of Custody Record is also included in Appendix C. After the borings are terminated, <br /> the borings will be backfilled with a slurry of cement, bentonite, and water. <br /> r <br /> -CoMloct <br /> 'o a r-Extraction ells D.� / <br /> f r 412�� <br /> We will observe the driller construct three 4-inch vapor-extraction wells in the <br /> borings drilled near the proposed tank cavity. 11The wells will be constructed of thread- <br /> jointed,4-inch-diameter schedule PVC casing I o chemical cements,glues,or solvents will <br /> be used in well cotrstruction. The scree ed portion of the wells will consist of factory- <br /> perforated casing with 0.020-inch-wid slots. The interval between 10 and 25 flet below <br /> grade will be screened using slotte casings. No_3 sand will be placed in the annular space <br /> opposite the screen to approxi ately 1 font above the top of the slotted casing. A 2-foot <br /> bentonite plug will be placed above the sand pack, and a cement-bentonite sherry will be <br /> 9 <br />