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Technical Memorandum 1 <br /> Liner Integrity Engineering Support ■ <br /> VLF2 Ore Stacking Recommendations <br /> Newl'ields Job No.475.0106.023 <br /> April 30,2018 <br /> The lift height shall be a minimum of 20' and a maximum height of 50' for ROM with <br /> greater than 3 inch maximum size rocks. <br /> To minimize the potential energy falling onto the DCF from the larger particle sizes, material <br /> with a diameter greater than 3 inches, it is recommended the maximum lift height be reduced <br /> to 50'. This is a common lift height observed in the industry where ROM material is being <br /> placed on heap leach pads. <br /> The 20' minimum lift height recommendation was developed to minimize the force transferred <br /> to the DCF and geomembrane from a loaded haul trucks. <br /> y When ore is being placed directly over the DCF, the material should always be placed in <br /> an uphill direction. <br /> When ore is being placed directly over the DCF, the advancement of material should always be <br /> in an uphill direction. This is an industry standard practice. Most damage observed to the <br /> geomembrane liner during stacking operations happens when ore is placed on a pad in a <br /> downhill direction. <br /> The overall slopes, which includes the bench width and the slope of the ore, shall have <br /> the following operational slopes based on a 100 foot lift thickness: <br /> o On ore slope against up-sloping ground is 1.6(H):1(V), a bench with a minimum <br /> width of 20' is required between the crest of the lower lift and the toe of the <br /> new lift. <br /> o Ore Slopes against down-sloping ground is 2.5(H):1(V), a bench with a minimum <br /> width of 110' is required between the crest of the lower lift and the toe of the <br /> new lift. <br /> o Ore Slopes above the Pregnant Solution Storage Area (PSSA) is 2.5(H):1(V), a <br /> bench with a minimum width of 110' is required between the crest of the lower <br /> lift and the toe of the new lift. <br /> o Ore slopes above the Mill Platform were designed to be 2.0(H):1(V), a bench with <br /> a minimum width of 60' is required between the crest of the lower lift and the <br /> toe of the new lift. <br /> Table 1 below summarizes the above guidelines information. <br /> Page 3 <br />