Technical Report for the Fort Knox Mine - Kinross Gold

Fort Knox Mine Technical Report17.2.13 Metallurgical RecoveryMetallurgical recovery is calculated for each model block and is based on a graderecoverycurve discussed in Section 16, Table 16-1. The following formula is applied todetermine the recovery for ore sent to the mill:Recovery % = (0.0411 * LN (Grade + 0.002) + 1.046) * 100The following formula is applied to determine the recovery for ore sent to the heap leachpad:Gold recovery at time t (days) = 0.65 - 1/ (0.03t + 1/0.65)17.2.14 Model ChecksThe interpolated gold grades in the block model are checked in detail against bothexploration and blasthole production drilling on both plan and sectional views using theMineSight software visualization tools. This checking has led to refinements ofinterpolation parameters to obtain a better fit with grade patterns in drilling data. Themodel and production reconciliation is also discussed in Section 17.4.17.2.15 Resource and Reserve ClassificationMeasured, Indicated, Inferred ResourcesAll model blocks with interpolated grade are assigned a confidence category identifier.The “anisotropically adjusted” distance to the nearest hole, number of composites andnumber of holes is stored during the interpolation using anisotropic ratios correspondingto the search ellipsoids. Only one drill hole was required to interpolate a block, andtherefore, the variables used to distinguish potential “Measured” blocks from “Indicated”block were the anisotropically adjusted distance to the nearest drill hole, and the numberof holes in the interpolation. The variable used to distinguish potential “Indicated” blocksfrom “Inferred” blocks was the anisotropically adjusted distance to the nearest drill hole.Resources are also limited by gold price and are exclusive of reserves. Distancerequirements to the nearest sample for each domain are listed in Table 17-4.62