Feasibility Study and Technical Report - Pretivm

8.0 DEPOSIT TYPESBased on the geological discussions presented in Section 7.0, the gold-silver quartz(± carbonate, barite, adularia) and minor base metal (galena, sphalerite, and rarechalcopyrite) veins and vein stockworks of the Brucejack Deposit are considered ashaving been formed in a transitional meso- to epithermal porphyry-associated quartzstockwork system in pervasively altered lower Hazelton Group rocks (quartz-sericite-pyritealteration as per the alteration zone of Sillitoe, 2010; Figure 8.1) between 192 Ma and184 Ma. Progressive development and telescoping of a porphyry system in the volcanicpile resulted in a widespread zonation of porphyry-style alteration and mineralization, andmultiple stages of vein and alteration overprinting. Gold concentration and subsequentdeposition probably occurred as a result of complex interactions between variousphysicochemical parameters (e.g. pressure, temperature, pH, activities of oxygen, sulphurand other volatiles, concentration of dissolved salts, differential permeability of thevolcanic pile) in the magmatic-heated seawater hydrothermal system developed abovethe pulsing porphyry system. Metal deposition was likely triggered by a combination ofstructural preparation, depressurization, cooling, phase separation, solution mixing, andfluid-host rock interactions. Geological, mineralization, and alteration features of theSnowfield Deposit (Armstrong et al. 2011) suggest that this deposit is more proximal tothe porphyry apophysis, most likely in the chlorite-sericite alteration zone of Sillitoe(2010) (Figure 8.1).Pretium Resources Inc. 8-1 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC