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Third Party Oversight 19 Weter, Weste & Lend, Inc. <br />San Luis Mine June 9, 1994 <br />' Figure 3 also demonstrates that although laboratory permeability values obtained from <br />tests conducted at relatively low (< 100 pcf) dry densities (SRK, 1994) are valid, they do not <br />I accurately reflect the quantity of compactive effort which was applied in the field as observed <br />by WWL. <br />According to BMRI's Technical Revision No. 16 (BMRI, 1993s1, permeability tests <br />indicated tailings values ranging from 1.9 x 10'8 to 5 x 10'' cmJsec. However, results from <br />WWL's review of available permeability data (included on Figure 3 and Table 5.1) show CPT <br />values for the tailings ranged from 1.9 x 10'5 to 5.9 x 10'8 cm/sec and piezocone values <br />ranged from 7.2 x 10'8 to 4.2 x 10'' cm/sec. The arithmetic and geometric means for the CPT <br />data are shown on Figure 3. Based on this data, a reasonable permeability coefficient for the <br />tailings would be between 2 x 10'8 and 4 x 10~B cm/sec. <br />5.5 DRAINAGE PIPE SPACING <br />In addition to the permeability of the drainage layer, drain spacing is critical to <br />controlling the height of head and minimizing the rate of seepage through the VLDPE liner. <br />DMG had expressed concerns after their initial site inspection that drains were being spaced <br />greater than the design value of 40 feet. Adequate spacing was verified during construction <br />oversight. <br /> <br /> <br />L~ <br /> <br />fir, <br />LJ <br />1 <br /> <br /> <br /> <br /> <br /> <br />