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1� <br /> Technical Memorandum <br /> Liner Integrity Engineering Support ■ <br /> VLF2 Ore Stacking Recommendations <br /> NewFields Job No.475.0106.023 <br /> April 30,2018 <br /> crushes ore and places it on the pad, the stability analysis completed to date has assumed the <br /> crushed ore is the only material on the pad as a conservative assumption since crushed ore has <br /> a lower strength than the ROM. Additional studies have included mixing crushed ore with <br /> materials with a higher percent of fines, like tailings, to verify the stability of the facility. Based <br /> on these analyses, the recommendations have been to place the mixed tailings in the interior of <br /> the pad where the finer grained material doesn't pose a geotechnical risk. <br /> When the lift consists of blended tailings material, this material should be placed a <br /> minimum distance of 25' back from the final exposed slope (outside face)of each lift. <br /> As discussed in the documents listed in the background section, the placement of the tailings <br /> material should not be placed near the outside face of any slope due to the lower shear <br /> strength associated with the finer grained material. Keeping the tailings within the interior of <br /> the pad, a minimum of 25 feet from the outside face, minimizes geotechnical risks associated <br /> with loading of the pad. <br /> y The nominal ratio of materials placed on VLF2 is 10%tailings to 90%ore. <br /> The percent fines in the tailings and some crushed ore will effect of the overall shear strength <br /> and permeability of the pad. Based on the stability evaluations completed, and documented in <br /> the Non Agglomerated Tailings Strength Assessment and Stability Evaluation, keeping the <br /> overall ratio of the material placed in VLF2 to a mixture of 10% tailings to 90% ore, crushed <br /> and/or ROM material, has minimal effect on the strength and stability of the facility. <br /> The lift height shall be a minimum of 20' and a maximum height of 100' for crushed ore <br /> and ROM with less than 3 inch maximum size rocks. <br /> The 100' maximum height was developed during the initial loading of the VLF1 pad to prevent <br /> the operators developing an excessive slope at angle of repose on the pad. The combination of <br /> the 100' lift heights and benches allows the operators to develop the overall slopes that are <br /> outlined below without additional reshaping. Additionally, keeping the maximum slope height <br /> limited to 100' with material less than 3 inches minimizes the initial loading stresses on the <br /> Drain Cover Fill (DCF). <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 /> Page 2 <br />