Feasibility Study and Technical Report - Pretivm

Table 16.9Ground Support RecommendationsOpeningTypeMain accessdecline, ramps,and otherhaulage routesLeveldevelopmentIntersectionsCross Section(w by h, m)GroundSupport TypeLength(m)Spacing(m)ShotcreteEstimate(%) Additional Notes6 by 5.5 Back Fully-grouted #7 Dywidag 2.4 1.8 by 1.8 10 -Walls Fully-grouted #7 Dywidag 1.8 1.8 by 1.8 105 by 5.5 Back Swellex Pm12 1.8 1.8 by 1.8 10 Fully-grouted #7 Dywidag can be used in directWalls Swellex Pm12 1.8 1.8 by 1.8 10 substitution of Pm12 when desired for operationalefficiency.Back Pre-support: Fully-grouted 2.4 1.8 by 1.8 10 Welded wire mesh should be installed on the back and#7 Dywidagupper portion of each wall for all intersections with anIncludes 6 by 5, 5 by5, three-way, fourway,and herringbonelayoutsBack Long support: Coupled fullygrouted5.0 2.4 by 2.4 10#7 Dywidag or cableboltsWalls Fully-grouted #7 Dywidag 1.8 1.8 by 1.8 10effective span greater than 6 m. Strap consumptionestimate: 25% of pillars; 3 straps per pillar.Full-width 5 m high by 6 m wide Back Pre-support: Swellex Pm12 2.4 1.8 by 1.8 N/A All support must be installed prior to slashing.undercutspilotBack Long support: Bulbed cable 6 2.4 by 2.4 N/AboltsWalls - - - N/A15 m wide full Back Swellex Pm12 2.4 1.8 by 1.8 25 All support except for shotcrete must be installed as eachundercut (post-slash) Walls Swellex Pm12 2.4 1.8 by 1.8 25 lateral slash is developed (prior to full width exposure)Portal - Back Fully-grouted #7 Dywidag 1.8 0.8 by 0.8 100 1 m spaced steel sets in first 30 m and 100% coverage- Walls Fully-grouted #7 Dywidag 1.8 1.8 by 1.8 -with minimum 50 mm thick steel-fibre reinforcedshotcrete throughout the length of the portalRaises 3 by 3 All Fully-grouted #7 Dywidag 1.2 0.8 x 0.8 50 Staggered spacing. Reduced support may be feasible ifman-access is not permitted.Notes: Design factor of safety is 1.3.Wall bolts must extend down to within 1.5 m of sill (floor).Surface support should be installed when excavation intersects relatively poorer ground, faults, more persistent joints or narrower joint spacing, soft joint walls,groundwater seepage points, or “dead” sounding difficult to scale material.Use shotcrete estimate percentage for mesh cost estimating if mesh is preferred surface support.All estimates are provided for cost estimating purposes only.Pretium Resources Inc. 16-31 1291990200-REP-R0012-02Feasibility Study and Technical Report on the Brucejack Project, Stewart, BC