Laserfiche WebLink
1# i <br /> Union Ice .'` <br /> " 2730 July 1991 <br /> 1k Al <br /> ! TABLE I and TABLE IIIrrgXrr rr9S,j;1 <br /> TABLE II4 <br /> "MW-8� and!'i "Monitoring Well 8", <br /> "EX-11 andj "Extraction Well 1" <br /> Boring logs ''EX-11 , "MW$" <br /> The nomenclature is confusing. The consultant must 'settle on one name for the <br /> extraction well and one name for the monitoring`}well ? I prefer that the names <br /> match the boring Togs; Extraction Well i or EX-1 and"Monitoring Well 8 or <br /> �F <br /> The site status is more difficult to summarize 4 an the missing reports and <br /> well nomenclature problem. I. have the following roblems with the <br /> investigation: p <br /> i <br /> 1. Wells MW-4S and MW-4D may be constructed improperly and it may not be <br /> possible to collect representative samplesifronithem. The log for well <br /> MW-4S indicated that concrete from adjacent wel'',11 MW-4D (ten feet away) <br /> is migrating into the boring for MW-4S. Concrete was observed on auger <br /> flights. I found no further explanation of this phenomenon in the file. <br /> What caused this? Was MW-4D pressure-grouted? ' Did the sand layer have <br /> anything to do with the movement of the concrete? Was an inordinate <br /> amount of concrete used during the constru'ction!:oof MW-4D? Was MW-4D <br /> properly grouted if concrete was found ten) feetjaway? Did the concrete <br /> interfere with the proper construction of MW-4S;? Was MW-4S developed <br /> properly? Were measurements of pH, EC, and temperature used to <br /> determine when ground water had stabilized. in MW-4S? (A high pH might <br /> indicate the, presence of fresh concrete. ) <br /> 2. Plates 4 and 7 in the 28 May 1991 Report show awater supply line that <br /> appears to run parallel and very close to MW -4S;� <br /> before reaching the`, and MW-4D but it is not <br /> clear if the line ends two wells. If the water line <br /> =does-pass ne4r7the W01—s;--is' it'possib`le­thAt"the 'concrete in MW-4S-was _•__. .,� <br /> from the water line? ,S <br /> 3. With soil saturated with- gasoline at abou0 16 feet and ground water <br /> occurring at the same depth, why does MW-4S not�dshow ground water <br /> contamination? <br /> 4. Why has MW-4D had contamination several times? ".If it was constructed <br /> properly, it should not be acting as a conduit for contamination from <br /> the upper aquifer to the lower aquifer. Are we therefore, to assume <br /> that contamination in sand at 16 feet has migrated through a clay layer <br /> to the lower aquifer in a sand layer encountered at 50 feet? <br /> 5. Plate 7 of the 28 May 1991 report shows 'a diagram of the excavation, <br /> indicating the locations and depths of soil samples. The plate <br /> indicates that the northern extension of the excavation was excavated to <br /> r <br />