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<br />retained on the 1" screen and may not have been larger than 1'fz inches -then: was no 1~/z inch <br />screen in use at the time.). <br />To demonstrate the effect of the oversize material in the soil liner fill on permeability, liner test <br />fills were constructed and in-situ permeability tests were performed. The permeability tests were <br />performed using a sealed single ring infiltrometer ("SSRI"). The SSRI, as you know, is <br />commonly used to measure in-situ permeability. Three test fills were constructed using the same <br />equipment that will be used during full scale construction of the soil liner at tte leach pad. The <br />first test fill was constructed with a combination of material that had been processed through the <br />pug mill and borrowed from the unprocessed stockpile. The pug mill was the first attempt to <br />process the tailing which proved unsuccessful. The pug has since been demobilized from the <br />site and replaced with a screening plant. The second and third pads were constructed with <br />material that had been processed through the screening plant. The third pacl was constructed <br />because the second pad had been consumed by attempts to successfully seat the SSRI. <br />The coefficients of permeability for the five tests are summarized in Table 1..Four "acceptable" <br />permeability tests were performed on the three test fills. The results of perm;ability Tests No. <br />1,2,3, and 5 give a range of permeability values that are consistent (Table 1). However, the <br />coefficient of permeability ("k") calculated from data collected during Test N~~. 4 indicated that <br />"k" was two orders of magnitude higher than any other test result. The soils technician who <br />performed the test believes the SSRI may have been leaking around the base. (Four additional <br />SSRI tests were attempted on the three pads but were unsuccessful as the seal between the soil <br />and the bottom of the ring failed during the test.) <br />TABLE 1. Coefficients of Permeability <br />TEST NO. COEFFICIENT OF <br />PERMEABILI'''Y <br />(k) cm/sec <br />1 1.9 x 10-8 <br />2 7.8 x 10.9 <br />3 1.4 x 10-8 <br />4' 2.4 x 105 <br />5 1.1 x 10-8 <br />' Test data not used because SSRI appeared to be leaking around base. <br />The geometric mean of the four "acceptable" tests is 1.2 x 10-8 cm/sec. Tie subject permit <br />requires that the Ironclad soil liner must be constructed from materials that achieve a coefficient <br />of permeability of less than 1 x l0a cm/sec. Thus the tests demonstrate aln•ost two orders of <br />magnitude lower permeability than required by the approved specifications. The data collection <br />