Feasibility Study and Technical Report - Pretivm

Table 13.14 Sample Specific Gravity (2012)SampleIDSpecificGravityVOK-1 Master Composite 2.87VOK-2 Master Composite 2.83VOK-3 Master Composite 2.77VOK-4 Master Composite 2.80WZ-1 Master Composite 2.74WZ-2 Master Composite 2.76Table 13.15 Sample Specific Gravity (2009 to 2010)SampleIDSpecificGravitySampleIDSpecificGravitySU-4 2.79 SU-25 2.71SU-5 2.74 SU-27 2.74SU-6A 2.82 SU-032A 2.73SU-6B 2.84 SU-032B 2.73SU-10 2.76 SU-032C 2.72SU-19 2.76 SU-033 2.78SU-21A 2.75 SU-036A 2.82SU-21B 2.77 SU-036B 2.7813.3.8 FLOTATION TEST WORKPRIMARY GRIND SIZESince 2009, different primary grind sizes have been tested by Inspectorate on thevarious composite samples . PAX and A208 were used as collectors, methyl isobutylcarbinol (MIBC) was used as a frother, and copper sulphate was used as an activator.The head samples were pre-concentrated by centrifugal gravity separation followed bybulk flotation.In 2012, the optimum primary grind size was further evaluated using the processconditions developed by Inspectorate during the previous test programs. The primarygrind test sizes ranged from 80% passing 38 µm to 80% passing 114 µm. Figure 13.1and Figure 13.2 show therelationships between primary grind size and overall gold andsilver recoveries (gravity and flotation) .Pretium Resources Inc. 13-12 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC