Feasibility Study and Technical Report - Pretivm

to form a series of seemingly stratigraphy-parallel pods within the steeply-dippingpolylithic conglomerate, and immediately overlying fragmental volcanic rocks in the coreof the syncline. These pods appear to be spatially associated with intensely silicifiedzones that appear to have acted as pressure seals, which generated local overpressureconditions and subsequent depressurization by hydraulic and/or tectonic brecciation.While there is some indication of a hard boundary between the polylithic conglomerate,and underlying fine-grained volcano-sedimentary and porphyritic latite flow volcanic rocks(previously termed "Jurassic" and "Triassic", respectively) in places, the mineralizationcrosses this contact. Gold and silver mineralization statistics for the volcanic andvolcano-sedimentary rock units present in VOK are very similar, suggesting (along withvisual assessment) that they can be treated as part of the same population forestimation. The boundary between the mineralized domains in the polylithicconglomerate and underlying volcano-sedimentary and porphyritic flow volcanic rocks is ahard contact in places due to the unconformity on the boundary with a generally weaklymineralizedsiliceous unit along most of the contact. There are places where thissiliceous unit does not exist and the boundary is gradational, with the sub-verticalmineralized corridors crossing the contact (Figure 14.2). In these places a soft boundaryapproach was used for grade estimation.Recent geological interpretation has shown that the area previously covered by GalenaHill is actually an extension of VOK, and this area has now been incorporated into VOK.14.5.2 WEST ZONEWest Zone was interpreted for the April 2012 estimate using a nominal 0.3 g/t Au cut-offgrade (Olssen and Jones, 2012a). There are no high-grade corridors defined at WestZone.14.5.3 DOMAINS USED FOR MODELLINGAfter review of the grade distributions for the mineralized corridors and different rocktypes at VOK, Snowden chose to evaluate/model each mineralized corridor using hardboundaries, but combining the various lithologies within the mineralized corridor. Therewere some exceptions where the corridors were interpreted to cross the lithologicalboundaries, and these contacts were treated as soft.The surrounding low-grade (background) domain was estimated as a single domain usingsoft boundaries, but excluding the high-grade population from within the high-gradedomains.The mineralized corridors within VOK change orientation locally. This was addressed byusing a series of "search domains" with locally adjusted orientations applied forestimation. The boundaries between these search domains were treated as soft forestimation.West Zone was estimated using a single mineralized domain.Pretium Resources Inc. 14-4 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC