Technical Report for the Maricunga Gold Mine - Kinross Gold

Kinross Gold CorporationMaricunga Mine Technical Reportevaluate crush size sensitivity of the Pancho ore. Gold recovery increased incrementally (3%- 6%), by crushing from 15.9mm to 9.5mm in size. Gold recoveries obtained from bothcomposites were essentially the same at the 9.5mm and 6.3mm feed sizes.Column test gold recovery rates for the 2240, Pancho 6, CCT and Oxide composites wererapid, and gold extraction was substantially complete in about 25 days of leaching. Goldrecovery rates were slower, and gold extraction progressed at a slow, but significant rateafter 75 days of leaching, for the 1690, 1840, 1930 and 2140 composites. The slowest goldrecovery rates observed were for the 1840 Shallow and RHEVC composites.Column test cyanide consumptions generally were high, but were not as strongly correlatedto copper head grade, as seen during bottle roll testing. Column test cyanide consumptionstended to increase with increasing leach solution application, as normally expected forcolumn leach tests. Because some of the column test leach cycles were relatively long induration (>140 days), the resulting cyanide consumptions were relatively high. Averagecolumn test cyanide consumption (6.3mm feeds) was 2.39 kg NaCN/mt ore.Column test lime additions were made based on corresponding bottle roll test limerequirement data. Lime requirements for the drill core composites varied substantially. Initialcolumn test lime additions ranged from 1.8 to 13.0 kg/mt ore. Those lime additions weresufficient for maintaining protective alkalinity during leaching, for most of the composites.Minor pH control problems were encountered during leaching of the 2140 and 2240composites, and relatively small lime additions were made to the column test barrensolutions during leaching, to help control leaching pH. Severe pH control problems wereencountered during leaching of the Oxide and CCT composites, and the lime added duringleaching for pH control was equivalent to more than the lime added to the ore initially. Thehighest observed combined lime requirement was 41.1 kg/mt ore, for the Oxide composite9.5mm column feed. Higher initial lime additions should be evaluated for these ore types todetermine whether or not pH control will be a problem during commercial heap leaching.Overall, reagent consumption data indicate potential concerns during commercial heapleaching of the Pancho ore, with respect to high cyanide consumptions related to copperdissolution, and high lime consumptions related possibly to interaction with sulphatesnaturally occurring in the ore. Follow-up testing was recommended to better establish baserequirements for pH control during heap leaching of the higher lime consuming Pancho ores.70