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La <br />Musco Olive Products -2- 31 October 1991 <br />Pond B CQA <br />4. Testing of liner construction was limited to nuclear gage determinations. <br />The enclosed Table 1 contains a recommended frequency for testing clay <br />liners in a construction quality assurance program. Tests for grain size <br />analysis, lab permeabilities, Atterberg limits and moisture/density tests <br />were not done on the clay liner. <br />One of the more important tests which was not completed is a density test to <br />provide a backup to the nuclear gage. We have seen cases where the nuclear <br />gage was improperly calibrated, or not adjusted for the soil used in <br />construction. By calibration we refer to the operators' knowledge of which <br />moisture density curve accurately reflects the clay being placed. This <br />curve can change during a construction project due to the heterogeneity of <br />soils. Sometimes the moisture content measured by the nuclear gage is not <br />corrected or adjusted to the oven -dried value so that the probe measurement <br />is "free" moisture and not water bound in the clay structure. The type of <br />calibration referred to in Addendum No. 1, while important, is not of <br />concern to us. Proper CQA tests are needed to verify proper operation of <br />the nuclear gage. <br />Sand cone and oven dried moisture contents are routinely used to verify <br />nuclear gage results. This type of verification is required for clay caps <br />in landfills. See CCR, Title 14. The clay cap at a landfill is very <br />similar in construction and function to the clay liner of pond B. <br />Recommended clay liner testing frequency specifications are published in <br />EPA/600/2-88/052. <br />Due to the above deficiencies, I cannot concur completely with KSA's determination that <br />the Pond B clay liner was constructed to Chapter 15 requirements. However, Pond B may <br />very well actually meet Chapter 15 requirements due to the following: <br />1. As demonstrated in the Design and Operation Report, there is a sufficient quantity <br />of clay soils on site, which when properly constructed, meet the 10-6 cm/sec <br />permeability requirement. <br />2. During staff inspections, observations of the clay liner construction indicate <br />that the contractors followed standard construction practices and the liner <br />appeared to be constructed without defects. <br />3. We have no reason to believe that the clay liner would not have a field <br />permeability of 10-6 cm/sec and meet Chapter 15 requirements. <br />4. The clay liner is overlain with a 45 mil hypalon liner and LCRS. The CQA Report <br />demonstrated that both systems meet the performance standards of Chapter 15. The <br />LCRS will be monitored on a daily basis and results will be submitted on a monthly <br />basis. Also, the LCRS will be tested annually to ensure that it is working <br />properly. <br />Based on these four items, I recommend that we accept the clay liner as being <br />constructed properly; however, we should strongly indicate that this type of CQA Report <br />will not be accepted in the future. <br />`- <br />