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5. Additional direct shear tests were performed subsequent to our July 8 letter, <br />and were presented in the August 17 letter. The stability analysis results <br />included in the August 17 letter used the measured friction angle (35 <br />degrees) and zero cohesion for the tailings, which is consistent with the <br />range of drained friction angle provided in Vick Table 2.8 for gold slimes. <br />6. <br />If there are further comments, please contact me. <br />Very truly yours, <br />measurements indicated an angle of internal friction which was higher than <br />published data; we used the upper limit of the published data. (continued in <br />item 5). <br />1- Z.14° <br />Ronald M. McO <br />Chairman & CEO <br />rmcomberActlthom <br />a. The configuration of the sand "layer" will be determined by the <br />flow characteristics of the cyclone sand at the time of <br />placement. In our August 17 letter, we used a 3:1 slope for the <br />inside and outside face of the sand. With the same strength <br />parameters used for both the sand and slime, the configuration <br />of the sand has no bearing on computed factors of safety <br />except for the outside slope of the tailings. We believe the 3:1 <br />outside slope is conservative, since literature suggests a 3:1 to <br />4:1 slope will actually occur. <br />b. See a. <br />c. See a. (Our rationale in the July letter was that the increased <br />fines content in the slime would justify some cohesion. Like Mr. <br />Cazier, we re- thought this assumption when we did our <br />supplemental analysis and eliminated the cohesion) <br />RMM /nt <br />(3 copies) <br />Attachment: Letter dated August 17, 2011 <br />via email: melderaunionmillinq.com <br />THE UNION MILLING COMPANY <br />TAILINGS POND EMBANKMENT AND FUTURE TAILINGS SLOPE <br />UNION MILL <br />CTL I T PROJECT NO. DN45,684 -130 <br />S:IPROJECTS1455000N45584 .000113013. Letters1L31DN45584. 130- L3.doc <br />2 <br />