Feasibility Study and Technical Report - Pretivm

There is significant variation in metallurgical performance, which is possibly due tonugget effects; therefore, the projections were based on average data, summarized asfollows:• The gold and silver recoveries reporting to gold-silver doré were projected basedon the gravity concentration test results, GRG gravity circuit simulations, andexperience. It was assumed that the smelting recovery is 99.5%. The slag fromsmelting will be ground and tabled to recover gold-silver alloy grains, and thetable tailings will be blended with the flotation concentrate.• The gold and silver recoveries reporting to the gold-silver flotation concentratewere estimated using the average locked cycle test results achieved at a primarygrind size of 80% passing approximately 75 µm, and the regression equationsthat were derived from the plots of the variability test results.• The flotation concentrate grade was estimated by the sulphur grade of theconcentrates produced from the locked cycle tests.For materials with head grades beyond the range of the tested heads, the metal recoveryand concentrate grade estimates were assumed based on test results and experience.The projections are detailed in Table 13.36 for the VOK Zone mineralization and Table13.37 for the West Zone mineralization.Table 13.36Head Grade(g/t)Metallurgical Performance Projection – VOK ZoneGold and Silver Recovery(%)Doré - Gold< 0.5 = 00.5 to 9.99 = - 0.147*((Head Grade, g/t) 2 ) + 5.68*(Head Grade, g/t) - 1.2149.99 to 40 = 7.32*ln(Head Grade, g/t) + 24.012> 40 = 52Doré - Silver 400 = 1.0Flotation Concentration - Gold< 0.5 = 300.5 to 5.64 = 85.44*(Head Grade, g/t) 0.056 + 0.147*(Head Grade, g/t) 2 - 5.68*(Head Grade, g/t) + 2.65.64 to 9.99 = 1.18*ln(Head Grade, g/t) + 0.147*((Head Grade, g/t) 2 ) - 5.68*(Head Grade, g/t) + 94.6949.99 to 40 = - 6.14*ln(Head Grade, g/t) + 69.558> 40 = 46.5Flotation Concentration - Silver< 3.0 = 353.0 to 130 = 2.793*ln(Head Grade, g/t) - (34.643*((Head Grade, g/t) - 0.48 )) + 78.07130 to 400 = 90.5> 400 = 91.5Pretium Resources Inc. 13-54 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC