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May Day Idaho Mine Complex 112 (d) Permit Application <br />The proposed milling process is as follows: <br />• Two initial stages of crushing will be used: a jaw crusher as primary crusher and a <br />cone crusher as secondary crusher; <br />• A vibrating screen in closed circuit will complete the crushing circuit; <br />• The crushed rock will pass through a rod mill followed by a ball mill; <br />• 'The slurry from the ball mill will go into a slurry tank and then sent to a classifier; <br />• Following classification, heavier material will be returned to the mills and the <br />lighter material will be sent to the conditioner and flotation tanks; <br />• Concentrate will be collected for further processing at an off -site location; and <br />• 'Tailings will be transferred to the stope for disposal. <br />During the optimization phase, the following processes will be evaluated: <br />• Recovery Optimization: The rate of chemical addition during milling will be <br />evaluated to maximize gold recovery. The proposed chemicals and application <br />rates are presented below. On -site management of the chemicals is presented in <br />the Environmental Protection Plan (Exhibit T, Sections 6.4.20.5 -7). <br />• <br />• <br />:Process <br />Chemical <br />Proposed Application <br />Rate (lbs chemical /ton <br />ore <br />Rod Mill <br />Sodium Carbonate <br />3.0 <br />Sodium Silicate <br />0.25 <br />Flotation <br />Biodegradable Surfactant <br />1.0 <br />Potassium amyl xanthate <br />15 <br />Sodium alkyl <br />dithio hos hate <br />0.05 <br />Copper sulfate <br />0.05 <br />Frother <br />Polyglycol ethers <br />0.10 <br />• Water and Chemical Recovery: A description of project water requirements and <br />sources is provided in Exhibit G — Water Information. Preliminary design <br />provides for 75% water recovery from the tailings prior to disposal, which will <br />also keep a portion of the chemicals within the process. This design will be <br />verified during the optimization phase. Additionally, the effectiveness of water <br />recycling and water quality will be evaluated with respect to recycling <br />optimization and potential disposal requirements, as discussed in the <br />Environmental Protection Plan (Exhibit T, Sections 6.4.20.5 -7). <br />May Day Idaho Mine Complex 112(d) Permit Application <br />September 21, 2010 <br />