Feasibility Study and Technical Report - Pretivm

Table 14.7Parameters to Describe Density ContinuityStructure 1 Structure 2Orientation Nugget Sill Range Sill RangeOmni-directional 0.05 0.47 20 0.48 10014.9 ESTABLISHMENT OF BLOCK MODELSA Datamine block model with cell dimensions of 10 mE by10 mN by10 mRL was coded toreflect the surface topography, base of overburden, lithological contacts, and themineralization domains. This block model was used for estimation of the density, lowgradedomains and the low-grade mineralized population within the high-grade domainsat VOK and the majority of West Zone.Within the well informed portion of West Zone, with close spaced drilling of around 5 mby 5 m to 10 m by 10 m, the parent cell size was reduced to 5 mE by 5 mN by 5 mRL forestimation of the background grades and low-grade mineralized population.Two small scale discretized block models were created for the multiple indicator krigingestimates so that these point estimates could be subsequently re-blocked to take intoaccount the correct degree of smoothing at the final block size. The discretized blockmodels have parent cells sizes of 2.5 mE by 2.5 mN by 2.5 mRL for VOK and the majorityof West Zone and 1.25 mE and 1.25 mN by 1.25 mRL for the well informed portions ofWest Zone.14.10 GRADE INTERPOLATION PARAMETERS14.10.1 HIGH-GRADE DOMAINS - LOW-GRADE POPULATIONThe lower-grade population, within the high-grade domains, was estimated using ordinarykriging into 10 m by 10 m by 10 m parent blocks for VOK and most of West Zone. In thewell informed portion of West Zone a 5 m by 5 m by 5 m parent block was used.At VOK, the mineralized corridors were estimated with hard boundaries for estimation,except where the corridors merge together. A series of "search domains" with locallyadjusted orientations applied for estimation to account for the local variability in theorientation of the corridors. The boundaries between these search domains were treatedas soft for estimation.For the West Zone, the high-grade domains were treated as a single domain forestimation for each area.Gold and silver grades were interpolated using 1.5 m composites with all data above thepopulation threshold removed (5 g/t Au and 50 g/t Ag for VOK, and 5 g/t Au and 300 g/tAg for West Zone). Estimation parameters were established from the variographyPretium Resources Inc. 14-13 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC