Feasibility Study and Technical Report - Pretivm

Mineralized quartz (±carbonate, ±adularia) veins, vein networks, and vein stockworks inand around the various mineral deposits in the Sulphurets Mining Camp display clear andabundant evidence for significant post-mineralization deformation, including:• tight through isoclinally folded veins• rootless intrafolial folded veins• apparently ptygmatically folded veins in less competent and deformed hostrocks• boudinaged veins• rootless boudinaged veins hosting gold mineralization tracing out tight folds andterminating at the vein contacts• transposition of veins into foliation planes with extension cracks perpendicularto the foliation• pinch-and-swell deformed veins with cuspate and lobate margins wrapped bythe foliation• mesoscale folded stockworks• brecciated veins• fracture offset veins• other small-scale post-mineral deformation features.These features are visible on the microscope (including strained and partially recrystallizedquartz in veins and vein stockworks), hand-specimen, drill core, and outcropscales.Development of the McTagg anticlinorium effectively exposed older pre-Salmon RiverFormation rocks in the Sulphurets Mining Camp. Rocks of the Hazelton Group andBowser Lake Group, which are located on the eastern limb of the north-plunginganticlinorium, display moderate to steep dips towards the southeast, east, and northeast,indicative of an overall eastward tilting of the original strata and porphyry-associatedmineralization in this area as a result of the Late Jurassic to Late Cretaceous deformationevent.En echelon arrays of late shallow southeast-dipping (25° to 40°) veins with vertical orsteeply-oriented crystal fibres in thin crack-seal textures cut across foliated andunfoliated altered and mineralized rocks, mineralized veins, and unaltered rocksthroughout the region. Arrays of similarly late sigmoidally-folded veins with a top-to-thesoutheastsense of shear are also present. These late quartz veins have beeninterpreted as having formed during the southeast-vergent thrusting that produced theSulphurets and Mitchell thrusts in the eastern part of the anticlinorium.The Brucejack Fault is a late, steeply dipping, northerly striking brittle structure whichforms a distinct topographical feature in the centre of the Sulphurets Mining Camp(Figure 7.4). Pre-existing folds, thrust faults, alteration, and mineralization zones are cutPretium Resources Inc. 7-10 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC