Technical Report for the Fort Knox Mine - Kinross Gold

Fort Knox Mine Technical Report17.2.9 Interpolation MethodologyThe “07d” block model was interpolated from MineSight Compass Multi-Run “06b IDW”developed in 2006. Gold grade is projected into model blocks from 30-foot benchcomposites with a series of interpolation runs using an ID 2 algorithm. In the first set ofinterpolations, the granitic host is modeled in the west, middle and east domains. Gold isinterpolated with 250x150x75-foot search radii for the granitic host in the west, middle,and east domains and 200x200x200 for the schist domain. In the second pass, whichoverwrites the first pass, gold is interpolated with 150x100x75-foot search radii for thegranitic host in the west, middle, and east domains and 110x110x110-foot search radiifor the schist domain. The domains were assigned “soft boundaries” between the granitedomains, allowing interpolation across the domain borders. However, the schist-granitedomain boundaries were “hard”, and so composites in the granite were not used ininterpolation of schist blocks, and vice-versa. The number of composites for a block is aminimum of 3 and maximum of 8. The maximum number of composites per hole is 4.The maximum 3-D search distance for composites greater than or equal to 0.300 ounceper ton gold was set at 25 feet.Schist blocks had their gold grades assigned a zero value. Operational experience hasshown that the very small zones of mineralized schist are difficult to identify during orecontrol. Therefore, it was considered appropriate to discard from the estimate any orecontained in the schist, which represented approximately 1% of the total ore.Drilling in 2007 added 41 holes to the 2007 “07d” model bringing the total number ofholes to 751 versus the 710 utilized in the 2006 “06b” model. The search parametersand variography generated for the 06b were utilized for the 07d model. Figure 17-4presents the 2006 histogram frequency plot and statistical summary of the interpolatedblock model grades for item “AUID” in the “07d” model.17.2.10 Search ParametersFGMI geologists and resource modelers established the ellipsoidal search directionsbased on blast hole and structural data in December 2004. The ellipsoidal search59