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. Additional Investigation to Define the Extent of Groundwater Contamination Quik Stop Market No 121 Page 2 Service Alert (U S A ), and retaining a private line location firm Shallow Monitoring Well Installation The 2-inch diameter groundwater monitoring well, MW-11, was drilled with a truck-mounted, B-53 drill rig, using 8-inch outside diameter hollow stem augers, which were cleaned prior to use The boring for this well was advanced to dense, wet sand, which was encountered at approximately 30 feet A CCI geologist logged the borehole by collecting samples at 5-foot intervals to the bottom of each boring Upon retrieval,the sampler was disassembled into its component parts One or more of the brass liners was selected for chemical analysis The ends of the selected liners were sealed with Teflon sheets, capped with plastic caps, labeled, logged on a chain-of-custody form and stored in a chilled chest containing ice for preservation in the field and during transport to the analytical Iaboratory Each boring was logged using the Unified Soil Classification System, and drill cuttings were placed in approved Department of Transportation (D O T) drums and left at the site pending laboratory analysis of the soil Deep Well Installation Due to encountering massive flowing sands during previous deep drilling at the site, a mud-rotary drilling rig was used to install monitoring wells MW-9 and MW-10 to depths of 75 and 76 feet, respectively A Mobile Drill B-8 drilling rig was set-up for the well installations A 6 5 inch diameter drill bit was used to drill the borings Drilling fluid, consisting of barite gel and water was circulated through the drilling rods as the wells were drilled As the borehole advanced,drilling fluid was circulated through the drill string and bit to shore-up the side of the hole and to help clean out the hole prior to installing the well casing Once again, a CCI geologist logged the borehole by collecting samples at 10-foot intervals beginning at 30 feet and at selected intervals to the bottom of each boring The soil samples were collected by pulling the drill string out of the hole, attaching a sample tube and slide hammer, then running the sampling tube back to the bottom of the borehole Upon retrieval, the sampler was disassembled into its component parts One or more of the brass liners was selected for chemical analysis The ends of the selected liners were sealed with Teflon sheets, capped with plastic caps, labeled, logged on a chain-of-custody form and stored in a chilled chest containing ice for preservation in the field and during transport to the analytical laboratory It should be noted, once the final depth of the boring was reached, the drilling fluid was thinned out with water in order to allow easier installation of the monitoring well casing and to allow the sand pack to more easily drop down to the screen interval At the conclusion of drilling activity at each . well, all the drilling fluid was placed in 55-gallon drums, properly labeled and left at the site