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0 GeoSyntec Consultants <br />On-site sandy lean clays will be used to construct the compacted clay liner. These <br />clays were used to construct the compacted clay liners within the base liners of WMU's <br />D-87, D-88, D-89 and the Eastern Ash Pit. Hydraulic conductivity values from field <br />testing for the Eastern Ash Pit typically ranged from 1 x 10-6 to 1 x 10-7 cm/s when <br />tested with air entry permeameters. These field tests are included with the CQA Plan in <br />Appendix C. The clay liner will be compacted to a minimum relative compaction of <br />90% (ASTM D1557), at a water content that will result in a hydraulic conductivity of 1 <br />X 10"6 cm/s or less. <br />If the on-site clays do not meet the hydraulic conductivity requirement of 1x10"6 <br />cm/s or less, an offsite clay (NARCO clay from Ione, CA) can be imported and <br />admixed with the on-site sandy lean clays for construction of the compacted clay liner. <br />This type of admixed clay liner has been used successfully in the construction of the <br />base liners for WMUs D-93, D-95, D-97, D-98, and D-99. A clay liner material <br />evaluation program was conducted in 1993 for the construction of the compacted clay <br />liner within D-93. When the on-site sandy clays were admixed with 25% NARCO clay, <br />and compacted to a minimum relative compaction of 90% at a water content of 2 to 5% <br />above optimum (ASTM D1557), a field hydraulic conductivity of 5 x 10-8 cm/s was <br />measured with a large-scale, sealed double ring infiltrometer (SDRI) installed through a <br />soil test pad. A copy of the clay liner material evaluation report for the admixed clay <br />liner, including the SDRI test result, is included with the CQA Plan in Appendix C. <br />J:\ALLIED\FORWARD\CLOSUREPLAN\REPORT 3-6 99.11.30 <br />I* <br />