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Soil Liner Fill -- Summary of Permeability Test Results -Freeze-Thaw Cycling Test <br />Material Type Number of Freeze-Thaw <br />Cycles Mean Permeability (cm/sec) <br />SLC-29 (1996 Clay Source; 0 6 x 10-09 <br />bentonite-amended) <br />3 oa <br />1x10- <br /> 5 7 x 10-09 <br />Ironclad (1994-5 Clay 0 3 x 10-os <br />Source) <br />3 ~ <br />4 x 10- <br /> 5 8 x 10-10 <br />The three samples of the 1996 source of clay material, amended with 2 percent bentonite, <br />showed some scatter in the permeability values, and also showed a lower permeability in the <br />baseline state than did the Ironclad material. The average of the three permeability <br />measurements after the five freeze-thaw cycles was 7.1x19 cm/sec, a slight numeric increase <br />over the average measured prior to exposing the material to freeze-thaw cycles. <br />Testing of the Ironclad material was performed to provide a translation from the field <br />measurements of density and moisture content that previously demonstrated a lack of adverse <br />affect of freeze-thaw cycles under actual field conditions of no Drain Cover Fill. (That lack of <br />impact was reported in CC&V's letter of Apri124, 1996. The average permeability for the three <br />samples of the Ironclad material subjected to the freeze-thaw cycling showed a decrease in <br />permeability with increasing number of freeze-thaw cycles. <br />As you will note from the Attachment, each and every test provided a permeability that met the <br />specification for the pad of < Ix10'6 cm/sec. <br />I think you will agree that these measurements demonstrate the suitability of using the two-foot <br />Drain Cover Fill. It would appear that any Soil Liner Fill material meeting the technical <br />specifications approved to date would not undergo an adverse increase in permeability upon <br />cyclical freezing and thawing and that the permeability would always meet the design <br />specification. <br />The laboratory tests were conducted in accordance with the test protocol attached to our letter <br />of May 15th. Grain size distribution, moisture content, and density were monitored to ensure <br />these materials met all applicable specifications. The Attachment describes the testing in some <br />more detail. <br />2 <br />