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. . • Mr. Greg Basso -4- 1-1 July 1989 Mr. Tom Woodward and include a required minimum number of tests for small construction areas and test pads. The CQA program does not address quality control of synthetic material used in WMU construction. This deficiency needs to be corrected. The CQA plan fails to discuss the use of nuclear gage density and moisture content measurements during liner construction. These tests should be included in the CQA table described above. Laboratory oven -dried moisture contents of the compacted soils need to be determined to verify the nuclear gage moisture measurements. Nuclear gage density, measure- ments should be verified with sand cone or similar tests. Daily calibration data for the nuclear gage should be submitted with final construction reports. Spot checks for plasticity index and moisture content are proposed as part of the liner construction CQA in order to monitor changes in soil properties. variations in soil properties such as visual appearance, grain size distribu- tion, optimum moisture and maximum dry density should also be spot checked. The criteria by which variations in each parameter are judged significant need to be explicitly defined in the CQA plan. A single ring infiltrometer is proposed for field permeabil- ity testing. The type of single ring infiltrometer needs to be specified and justification for its use needs to be provided. Our concerns include the small surface area of the liner typically measured by single ring devices and the potential to overlook macroscopic hydraulic defects. The small number of proposed tests may not identify permeability variation in the test pad or completed liner. Record drawings of the subgrade elevations and finished liner need to be provided in the final construction report. We understand that you would like to coordinate construction of WMU D89 with the closure activities on WMU A this summer. Please provide a revised WMU D89 construction plan and CQA plan at least 2 weeks prior to the start of D89 construc- tion. Failure to do so may result in violation of the facility's WDRs.