ARCHIVED REPORTS XR0012541 - Laserfiche WebLink

Home Browse Search

F 4 FIELD INVESTIGATION The first phase of the field investigation program �;as based Primarily on that proposed (and approved by both Anheuser- Busch, and the San Joaquin Local Health District) in the Contamination Assessment Plan, dated June, 1987 (ESE, 1987 ) . burin the 9 field investigation program, which took place ! during the week of Jul y 6,- 19a7, the first monitor cell, t-tt4-1 , located northeast Of the excavation :area was installed. St 's approximate location is shown in Figure 47.1 ,. with a scaled {� sketch oxesented in the ,"operdix. The second phase of the investigation took place from i ; September 3 through September 8, and included the installation Of 1114--•2 and 111-4-3, whose locations are similarly shown in Figure 4-1 . - D.lrirg w.Pll construction, soil and ground eater samples were "y cc,lluctec; for lithologic description and chemical analyses . E Sampling methodology and field investigation results are summarized in the following sections. 4 . 1 METHODOLOGY 4 . 1 . 1 PhaseI i. Dcring PI- ase I, one monitor •well was constructed using mud rotary techniques.q s. Mud rotary drilling was aelerted over hollow stem techniques because flowing sand, firer,- suspected in the area (based on ESE' s drilling e;?perience within, a 1.0 mile radius of the site ) . Because rotary drilling stabilizes the walls of the wells, pxeveAtin9 s.a ands from m flowing ng upwards-,r d c- , a,c was presumed that this technique would have the :�dvantaJe of assuring a true, depth di-wrete sample from the depth of interest.' 11ud-rotary similarly accommodates the installation y !. of a larger, 4 inch diameter well , which may prove advantageous if site remediation is required. The mud rotary a1 , r