The Capoose developed prospect is situated south of Green Lake, approximately 9 kilometres east of Capoose Lake and 110 kilometres south-southeast of Burns Lake.
The Capoose region is predominantly underlain by Lower to Middle Jurassic volcanic and sedimentary rocks of the Hazelton Group. These assemblages are overlain by the Upper Cretaceous–Eocene Ootsa Lake Group and Miocene plateau basalt. Lower Jurassic rocks of the Hazelton Group in the northeastern part of the map sheet are intruded by a belt of granodiorite, diorite and quartz diorite plutons of the Late Triassic–Early Jurassic Topley Intrusions. Felsic plutons of probable Cretaceous age intrude Lower and Middle Jurassic Hazelton strata.
The Capoose prospect is underlain by moderately to steeply southwest dipping Hazelton Group andesite flows, andesite-dacite tuffs, and argillite/siltstone. These are intruded by quartz monzonite of the Capoose batholith that dips gently eastward to about a kilometre depth below the deposit. The batholith is mapped over a 7 by 18 kilometre area west of the deposit and spans the Late Jurassic to Late Cretaceous from its west to east margins. Apparent fragmental rhyolite sills with sheared contacts are the prime host of mineralization and are intensely altered with a silica-sericite-clay and garnet-bearing assemblage similar to the Blackwater deposit (093F 037). The sills or “undifferentiated silicified volcanics” cut across the biotite hornfels aureole at the upper contact of the batholith and based on garnet geochemistry are similar in age to the east margin of the batholith (Geological Fieldwork 1992 (Green and Diakow, 1993)).
The deposit is elongated north-northwest parallel to stratigraphy over an 850 by 1000 metres surface area, and dips to the west below 300 metres depth. Mineralization occurs as pyrite-sphalerite-galena-chalcopyrite-arsenopyrite disseminations, aggregates, and lesser veinlets. Precious metals occur as inclusions within the sulphides. Tetrahedrite, pyrrhotite, pyrargyrite, electrum and native gold occur as inclusions within the more abundant sulphides. Gold grade increases toward structural intersections with northwest trending linear features that are first derivative magnetic features. A late northeast dipping clay-altered rhyolite dike cuts mineralization, with later northeast trending faults offsetting the dike.
Analysis of alteration sericite crystal structure indicates higher temperatures than at the Blackwater deposit. Both andradite and spessartine garnets occur with the magmatic-to-hydrothermal transitional early potassic assemblage and have been subsequently replaced by sulphide. These mineralogical features along with the proximal and coeval nature of the sills to the batholith and structurally confined mineralization suggest the Capoose deposit represents a deeper, hotter feeder system to a Blackwater-style deposit.
In 2012, the resource was stated at 14.2 million tonnes grading 0.43 gram per tonne gold and 20.8 grams per tonne silver (Indicated); and 64.1 million tonnes grading 0.29 gram per tonne gold and 23.2 grams per tonne silver (Inferred) (Exploration and Mining in British Columbia 2013, page 24).
An updated Indicated resource estimate incorporating 2013 drilling program was, at a cut-off grade of 0.4 gram per tonne gold equivalent: 20.3 million tonnes at 0.50 gram per tonne gold and 22.4 grams per tonne silver; containing 9953 kilograms gold and 454,733 kilograms silver; an additional 29.3 million tonnes averaging 0.39 gram per tonne gold and 26.3 grams per tonne silver is classified as Inferred (Simpson and Rotert, 2014). The effective date of the estimate was December 31, 2013.
The Capoose deposit was discovered in 1970 by Rio Tinto Canadian Exploration Limited (later known as Riocanex). In 1973, Granges Exploration carried out a regional geochemical stream silt sampling program. Anomalous molybdenum, copper, lead, zinc and silver values were discovered on a portion of the Capoose property belonging to Riocanex. Riocanex allowed the claims to lapse in 1975, allowing Granges to stake claims over the anomalous area. The following year, Granges conducted grid establishment, geochemical soil sampling and magnetic geophysical surveying on the B and D claims. There was sufficient interest in the results from the D claim to return the following season and carry out further geochemical soil sampling, hand trenching and prospecting, as well as geochemical soil sampling on the E and F claims to the immediate south.
In 1978, Granges Exploration completed 20 percussion-drill holes totalling 551.03 metres on the D and E claims. Two of the holes intersected zones of marginal mineralization up to 27.4 metres in length, while several 3.05-metre sections of ore-grade mineralization were encountered in other holes. The following year, nine BQ diamond-drill holes totalling 1434.4 metres were completed on the E claim and an electromagnetic geophysical survey was carried out over the D and E claim areas. In 1980, 17 BQ diamond-drill holes totalling 3376.1 metres were completed around the E claim area.
In 1983, Granges completed an exploration program consisting of geochemical soil sampling and trenching on the B and D claims. In total, 136 soil samples were collected and two shallow trenches were blasted. A geological mapping program focussing on the D and E claim areas was carried out in 1985. Later that year, a small soil sampling and diamond drilling program was carried out immediately south of Green Lake on the B claim.
In 1996, Pan American Silver acquired the property from Granges Exploration and Cominco Limited. The claims were later allowed to lapse and the property was restaked by the Peregrine Syndicate in 2000. The property was staked by the Peregrine Syndicate in 2000 and work that year comprised the collection of rock and drill core. In total, 27 samples were collected (Assessment Report 26573).
Silver Quest Resources Ltd. later acquired the property as part of their Capoose project. In 2008, Silver Quest drilled 11 diamond-drill holes. Ten of the drillholes intersected zones of significant mineralization. The following year, a 193-sample geochemical soil survey was completed; as well an additional 13 diamond-drill holes totalling 1395 metres.
In 2009, Richfield optioned the Davidson property from Silver Quest Resources Ltd. (Silver Quest) and the Dave and Jarrit claims from private individuals. Richfield subsequently completed all of the earn-in requirements for these agreements resulting in it holding a 75 per cent interest in the Davidson property and 100 per cent interests in each of the Dave and Jarrit properties.
In 2010, Silver Quest Resources Ltd. carried out an exploration program consisting of diamond drilling and ground magnetic geophysical surveying. Silver Quest completed 37 core holes totalling 10,598 metres aimed at upgrading and expanding the gold-silver resource. Based on drilling up to 2010, a new resource estimation calculated the inferred mineral resource at 53.45 million tonnes in the inferred category grading 0.41 grams per tonne gold and 23.9 grams per tonne silver at a gold equivalent cutoff of 0.4 gram per tonne gold. One of the best holes drilled in 2010, D-10-127, intersected 0.74 gram per tonne gold and 9.37 grams per tonne silver over 301.5 metres. Significant zinc occurs throughout the 301.5 metre length, as demonstrated by sub-intervals of 0.74 per cent zinc over 48 metres, 0.75 per cent zinc over 26 metres and 0.43 per cent zinc over 26 metres (Information Circular 2011-1, page 27).
In 2011, Aeroquest Airborne conducted a 2594 line-kilometre airborne geophysical survey over the entire Capoose property (Assessment Report 32672).
In June 2011, New Gold acquired all of the issued and outstanding common shares of Richfield pursuant to a court approved plan of arrangement. In December 2011, New Gold acquired all of the issued and outstanding common shares of Geo Minerals Ltd. (Geo) and Silver Quest. New Gold subsequently amalgamated with Richfield, Geo and Silver Quest effective January 1, 2012 and became the direct operator of the Project. In March 2012, New Gold purchased the Auro Property from Gold Reach Resources Ltd. (Gold Reach). Several other private property purchases were also completed between 2012 and 2015.
In 2011 and 2012, New Gold collected 1828 till and 79 silt samples in the Blackwater deposit and Capoose prospect areas (Assessment Report 35158). In 2012, New Gold’s drilling at Capoose approached 11,000 metres in over 22 holes. Early assay results showed mineralization both within and beyond previously defined boundaries.
In May 2014, New Gold released a National Instrument (NI) 43-101 technical report on the Capoose project by R.G. Simpson and J.W Rotert. The mineralized zone (above 0.4 gram per tonne gold equivalent) is irregularly shaped and extends 825 by 715 metres along a north-south trend, with a vertical extent of over 500 metres (Information Circular 2015-1, page 15).