SITE INFORMATION AND CORRESPONDENCE

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Jim Pinasco October 22, 1992 Page Two Comment 2 On page 3-10 regarding Well 1, the Draft Report states: "The cement bond and compensated density logs did not indicate the presence of void spaces or cement between the outside of the well casing and the formation. " GSU interprets that the variable density log for Well 1 appears to show few formation wave arrivals. This interpretation is made because all of the early arrival waves are parallel due to the uniform pipe transit-time. Formation signals are normally easily identified by their characteristic wiggly lines which are caused by the variation of formation transit time with depth (Brown and others, 1970) . Recommendation From evaluation of the variable density sonic log of Well 1, GSU interprets that the majority of the interval from 225 to 385 feet below ground surface (bgs) may have a micro-annulus outside the casing which should have been perforated and pressure grouted. In addition, it should be noted that the formation opposite this interval is recorded as clays on the lithologic log. Comment 3 On page 3-10 the Draft report states that the natural gamma and neutron logs indicated possible permeable zones at the following depths listed below, and that based on these results, it was decided to perforate these depth intervals: 152 to 163 feet below grade 205 to 217 feet below grade 506 to 511 feet below grade As stated in meetings before abandoning these wells, GSU interprets that perforating permeable units prior to grouting wells during decommissioning is counter productive. Excessive amounts of grout will likely have to be used to seal off these permeable units, and even if sealing off these permeable units is successful, the result is that the aquifer may be sealed, but that an annulus or micro-annulus may still exist in aquitard units, which interconnect aquifers. Page Three