Summary:
The Brewery Creek deposits exhibit characteristics of both intrusion-related and epithermal type deposits. It is generally considered to be an alkalic intrusion-associated, gold deposit as most of the mineralization is concentrated within or proximal to the monzonites. Geological, geochemical, petrographic and fluid inclusion data indicates that original sill emplacement, first stage alteration and associated mineralization occurred at a relatively low temperature and high level within the crust. However, the presence of wispy-textured quartz veinlets, related to later shear zone deformation, indicates deposition at moderate to deep levels (Dunne, 1995), a common characteristic of epithermal type deposits (Poulsen,1996).
Historical production on the property occurred along the historical BCRT. The Brewery Creek District consists of numerous deposits, mineralized zones and past producing deposits both along this trend as well as within peripheral mineralized areas. Past producing areas within the BCRT include the Pacific, Blue, Canadian, Upper Fosters, and Kokanee, Golden and Lucky deposits. Additional to these, Mineral Resources have been defined for the Big Rock West, Big Rock East, Lower Fosters, Bohemian and Schooner deposits along the BCRT; the North Slope deposit north of the BCRT; Sleeman deposit east of the BCRT, and the Classic and Lone Star deposits south of the BCRT. Mineralized areas peripheral to the BCRT, including Moosehead, have not been considered for the purposes of this report.
Kokanee
The Kokanee deposit was mined by Viceroy from four pits; all pits were partially backfilled. The southern two pits remain mostly open while the northern two are almost entirely backfilled and reclaimed. The deposit is centrally located along the BCRT and formed in the thickest and most extensive part of the Cretaceous quartz monzonite sill complex. The deposit is ~1100 meters in length, ~40 meters wide, and ~190 meters down dip.
Mineralized material at Kokanee occurs primarily in the quartz monzonite sill complex and subordinately in siltstone and argillite. Observations of mineralized material exposed in pit walls shows millimeter-scale veinlets with ironoxide ± quartz fillings. The mineralized quartz monzonite typically contains several percent of evenly disseminated oxidized pyrite.
Golden
The Golden deposit lies immediately east of Kokanee and may be a faulted offset of Kokanee. It was mined by Viceroy from 4 pits; three were backfilled and reclaimed, the lowest and farthest south pit was not backfilled and remains in its fully mined state. The deposit is ~950 meters in length, ~30 meters wide, and ~150 meters down dip.
Golden, like Kokanee, is hosted by the thickest and most extensive part of the Cretaceous quartz monzonite sill complex. The K-feldspar component of quartz monzonite, both phenocryst and groundmass are altered to white clay.
Pacific
The Pacific deposit was mined by Viceroy; the pit was not backfilled and remains in its fully mined state. Pacific lies along the Reserve Trend, immediately east of the Classic Fault. The deposit is ~500 meters in length, ~50 meters wide, and ~300 meters down dip.
Pacific is the only deposit in the district that is hosted primarily by lower Paleozoic siltstone. Mineralization is generally tabular and follows a combination of shallow south dipping bedding and high-angle BCRT-parallel faults. Higher grade parts of the deposit are steeper along these faults. The deposit has been segmented by several post-mineralization northwest-trending dextral faults.
Blue
The Blue deposit was mined by Viceroy, and the pit was partially backfilled and reclaimed. Blue lies directly east of the Pacific deposit along the BCRT. A fault separates the two deposits; one possible restoration of displacement suggests that the two deposits may have been a single mineralizing system. The deposit is ~560 meters in length, ~45 meters wide, and ~200 meters down dip.
Blue is hosted primarily by Cretaceous quartz monzonite and subordinately by lower Paleozoic siltstone. Mineralization is generally tabular and follows the strike and dip of the sill complex. Unlike Pacific, the primary strike of the deposit lies along a series of northeast-trending faults. A strong discontinuity in stratigraphy, sill development, and mineralization occurs at the eastern end of the deposit. An area of poorly defined mineralization occurs immediately southeast of the deposit, suggesting a possible post-mineralization offset of the deposit along a northwest trending fault.
Lucky
The Lucky pit was mined by Viceroy, partially backfilled and reclaimed. The deposit occupies the northeastern-most segment of the BCRT. It is situated immediately west of the BohemianSchooner deposits and northeast of the Golden deposit. The deposit is ~550 meters in length, ~50 meters wide, and ~360 meters down dip.
Altered Cretaceous quartz monzonite that intrudes lower Earn Group sedimentary rocks host mineralized material at Lucky, similar to that at Bohemian-Schooner. Dominant mineralized trends typically strike 035° or 060° and dip moderately (-25 to -45) to the southeast. Mineralized material in the hanging wall is abruptly terminated to the northwest by Steel-formation sedimentary rocks at the footwall contact of a major 040° trending fault.
Bohemian-Schooner
The Bohemian-Schooner deposit and surrounding mineralized area was originally discovered by soil sampling, trenching and drilling in the 1990’s by Viceroy. The area remains unmined and is defined by 129 reverse-circulation drillholes and 122 core drillholes, totaling 23,385 meters. A linear distance of approximately 7 km separates the zone from the old heap leach pad. The Bohemian deposit is ~520 meters in length, ~50 meters wide, and ~160 meters down dip. The Schooner deposit is ~450 meters in length, ~50 meters wide, and ~160 meters down dip.
Gold mineralization at Bohemian/Schooner occurs primarily in clay-altered quartz monzonite sills and subordinately in adjacent siltstone. It occurs most commonly in association with strong argillic altered and locally silicified quartz monzonite. Sheeted and stockwork mm- to cm-scale quartzpyrite-arsenopyrite veins, commonly forming conjugate patterns in detail, cut the altered intrusion and occur in association with higher grade zones.
Canadian-Fosters
The Fosters mineralized resource area includes only the un-mined Lower Fosters deposit which lies approximately 3.5 km from the current heap leach pad. The Upper Fosters and Canadian deposits have been mined historically and are not part of this Mineral Resource. The Lower Fosters deposit (the only part of the complex reported in this study) is ~550 meters in length, ~30 meters wide, and ~260 meters down dip.
A large sill complex extends throughout the Canadian-Fosters area and hosts most of the known mineralization. It has a strike length of at least 1.2 km and a down-dip extent of at least 500 meters. It strikes 070° azimuth and dips approximately 20° southeast. The sill complex contains large interleaves of sedimentary strata and splits into a complex array of individual sills along strike and dip.
West and East Big Rock.
The West and East Big Rock deposits are the furthest westerly known occurrence in the district and are located approximately 1.2 km from the current heap leach pad. The West Big Rock deposit is ~650 meters in length, ~30 meters wide, and ~220 meters down dip. The East Big Rock deposit is ~640 meters in length, ~30 meters wide and ~180 meters down dip. Mineralization occurs primarily in limonite-altered quartz monzonite sills and subordinately in adjacent siliciclastic sedimentary strata.