The Galena Hill area is underlain by rock of the Lower Jurassic Unuk River Formation, Hazelton Group. These rocks consist of sandstone, wackes and shale overlain by lapilli tuff of andesitic composition. The Brucejack fault and associated splay faults cut the country rock in a north-south to northwest direction. North of Brucejack Lake the fault system is bounded on the east by rock of the Lower Jurassic Betty Creek Formation, Hazelton Group. A variety of Jurassic hornblende syenites and alkali feldspar syenites occur in the area.

The Galena Hill galena-stockwork occurrence is a vein structure occurring within andesitic tuff breccia. It consists of a quartz and minor sulphide sheeted stockwork at its east end and a thick quartz vein at its west end. The eastern end, known as the Stockwork zone, is isolated from the western end, the Galena zone, by a till covered 100-metre gap.

The Galena Hll area is characterized by weak sericitic alteration. The thick quartz vein is mineralized mainly with fine disseminated pyrite, sphalerite, tetrahedrite and a trace of electrum. On the north side of the quartz vein, a halo of quartz, quartz-sulphide, and quartz veins with electrum has formed (Assessment Report 10698). Other reports also mention the occurrence of galena, chalcopyrite and native gold in quartz and barite veinlets (Fieldwork 1982).

Galena Hill is situated between the West Zone and Bridge Zone gold deposits on a prominent hill marked by widespread iron oxide staining of altered meta-andesites. The Galena Hill zone had been previously tested with 27 boreholes belonging to a number of different drilling programs, with half of the holes being less than 100 metres in length. Assays from these holes, together with detailed geological mapping and channel rock-sampling, indicate that at Galena Hill there is a system of mainly east-west trending quartz veins and quartz stockworks which define an envelope of hydrothermal alteration and mineralization that is at least 400 metres long and 300 rnetres wide (Technical Report and Preliminary Economic Assessment on the Brucejack Project by Wardrop for Pretium Resources Inc, June 3, 2011). In 2009, rather than target the larger quartz veins which locally contain high-grade gold and silver mineralization on surface, Silver Standard focused on testing for the potential of a low-grade, bulk-mineable deposit (Assessment Report 32074). This was done with eight relatively long (>400 metres) drill-holes. The majority of these boreholes passed through amygdaloidal and massive andesite flows, volcaniclastic deposits rich in lapilli-sized andesitic clasts and thin units of carbonaceous and cherty mudstones. A few holes intersected bodies of highly siliceous rock that were interpreted to be rhyolitic dikes and by others to be zones of pervasive and intense silicification. One drillhole, SU-005, yielded a 50-meter-long quartz vein intercept enriched in gold and silver along its margins, though it is likely that this intercept is at a low angle to the dip of the vein. As in the West zone, gold mineralization at Galena Hill is preferentially associated with quartz veins, although the sericite-altered, andesitic host rocks are typically mineralized with disseminated pyrite and have geochemically anomalous gold contents, generally in the 100-500 ppb gold range. In some veins, trace to minor amounts of native gold and electrum are accompanied by minor to occasionally substantial amounts of sphalerite, chalcopyrite and galena.

Drilling in 1982 intersected a sheeted stockwork with an apparent true thickness of 35 metres with an average assay of 2.4 grams per tonne gold. Assays up to 724.0 grams per tonne gold over 0.7 metres occur but the consistency of mineralization is not sustained (Bridge and Melnyk, 1983). Grab samples contain up to 1276.0 grams per tonne silver (Fieldwork 1982).

The highest grade obtained in 2009 intersected spectacularly rich gold mineralization. Drill hole SU-012 gave impressive assays of 16.95 kilograms gold per /tonne and 8.69 kilograms silver per tonne over an intercept length of 1.5 metres (Assessment Report 32074). This new zone appears to lie in a low gully between Galena Hill and Electrum zone. This small northwest trending linear is now known as The Valley of Kings (104B 199).

The 5.9 vein is part of a stockwork or sheeted vein zone occurring within weakly sericitic andesitic tuff-breccia in the northeastern area of the Galena Hill zone. The 5.9 vein is between 20 to 100 centimetres thick and up to 40 metres in length. This vein assayed 185.14 grams per tonne gold and 18617.0 grams per tonne silver over 20 centimetres (Bridge, D., Melnyk, W., 1983).

Refer to West (104B 193) for details of related mineralization and work history.