Feasibility Study and Technical Report - Pretivm

y the Brucejack Fault as well as by many other similar late northerly-striking faults.Movement on the fault is probably complex and has been difficult to determine. A muchthicker section of Hazelton Group rocks on the east side of the fault suggestsconsiderable east-side-down displacement, which may be interpreted as reflecting postdepositionaldisplacement. Kirkham and Margolis (1995) indicate that the BrucejackFault appears to have an east-side down dip-slip displacement of greater than 500 mwith a dextral strike-slip component in the area north of the Snowfield Deposit, andapproximately 100 m of dextral strike-slip with uncertain dip-slip on the Property. Davieset al. (1994) noted that, northwest of Brucejack Lake, preserved slickenside and castelongation lineations on a steeply west-dipping surface indicate dip-slip offset ofpotentially between 700 m and 800 m with a reverse fault sense of movement (i.e. westsideup). Stratigraphic contacts a short distance northwest of the Brucejack Lake havebeen interpreted as indicating a possible strike separation of between 200 m to 300 m,and dip-slip displacement is likely less than in the north. In contrast, Britton and Alldrick(1988) considered that displacement on the Brucejack Fault was on the order of tens ofmetres. Elsewhere in the Sulphurets Mining Camp the northerly, north-easterly andnorth-westerly striking brittle faults, and rare east-west striking faults, display typicallysteep dips, steeply-plunging fault fabrics, and locally normal-dextral obliquedisplacements of up to tens of metres.The possibility that the Brucejack Fault structure was formed as a result of late brittledeformation re-activation of a pre-existing syn-depositional fault developed at or near avolcanic sub-basin margin during deposition of the lower Hazelton Group is beingconsidered based on recent fieldwork. If this hypothesis is correct then, given the spatialproximity of the fault to the alteration and contained mineralization zones on theBrucejack and Snowfield Properties (Figure 7.4), it may have partly controlled thehydrothermal alteration and mineralization in this part of the Sulphurets Mining Camp.Rocks of the Sulphurets Mining Camp were subjected to, at most, lower greenschistfacies metamorphism characterized by epidote, calcite, quartz, and chlorite, and theabsence of biotite, hornblende, and actinolite in andesitic volcanic rocks andsedimentary rocks outside of the areas of hydrothermal alteration. The peakmetamorphic temperature probably did not exceed 275°C (assuming a 3 km depth ofburial).7.3 PROPERTY GEOLOGYThe information in this section on the Property geology is summarized and updated fromthe work of Mr. Charles Greig, Senior Geologist for Pretivm, as presented in Olssen andJones (2012a).Geology on the Property can generally be characterized as a northerly trending, broadlyarcuate, concave-westward structural-stratigraphic belt of variably altered rocks. Thisbelt is bisected on the western side of the Property by a prominent topographiclineament, the Brucejack Fault (Figure 7.3 and Figure 7.4). To the south of BrucejackLake, the belt generally displays a north-easterly trend, rotating towards the northwestnorth of the lake. The arcuate trend is outlined by the stratified rocks and the intenselyPretium Resources Inc. 7-11 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC