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6.2.4 Regrind Circuit <br />Prior to entering the leach circuit, the ground flotation concentrate will be sent to a <br />regrind mill to further reduce the particles to 25 microns in size to promote additional <br />gold liberation in the leach circuit. Like the initial grinding circuit, the regrind circuit <br />will operate in a continuous loop using a hydrocyclone to sort the particles according to <br />size. The hydrocyclone overflow, which is properly sized, will proceed to the leach <br />circuit while the underflow will return to the regrind mill for further grinding. <br />Before entering the leach circuit, water in the fine concentrate slurry will be removed so <br />the slurry will be thickened. The thickener allows the particles in the slurry to settle and <br />allows clear water to be captured and for re -use in the mill. This will decrease the <br />amount of fresh water needed to operate the grinding and flotation circuits. The <br />dewatered concentrate from the thickener will be pumped to the leach circuit. <br />6.2.5 Leach Circuit <br />The leach circuit will dissolve the gold in the fine concentrate slurry through the addition <br />of a dilute sodium cyanide solution and addition of lime to control the solution pH. <br />Recycled water from the leach or CIP circuits will be added to the slurry to reduce the <br />slurry density. This will occur in the same tank where the pH adjustment occurs. The <br />mill circuit will have two streams of recycled water: one stream of recycled water is that <br />solution where dilute sodium cyanide solution will be used and one stream of recycled <br />water is solution where dilute sodium cyanide will not be used. The mill will have these <br />two streams of recycled water to minimize the areas where sodium cyanide will be <br />present. From the pH adjustment tank, slurry will be directed by gravity to the first of six <br />leach tanks in a single train. Each tank will be fitted with an agitator to ensure the slurry <br />makes contact with the dilute sodium cyanide solution. Air will be introduced to each <br />tank to promote gold dissolution rates. The discharge from the last leach tank will flow <br />into the CIP circuit. <br />Cripple Creek & Victor Gold Mining Company <br />Cresson Project Mine Life Extension 2 <br />6 -6 <br />