The Red Dog occurrence is located in the northern headwaters of the Goodspeed River, approximately 7 kilometres west of the western end of Nahwitti Lake.
Regionally, the area is underlain by northwest-trending belts of basaltic volcanics and carbonate sedimentary rocks of the Upper Triassic Karmutsen and Quatsino formations (Vancouver Group) and mafic volcanics and sediments of the Upper Triassic to Lower Jurassic Bonanza Group (Holberg volcanic unit, Nahwitti River wacke and Parsons Bay Formation). These volcanic and sedimentary rocks have been intruded by granodioritic rocks of the Early to Middle Jurassic Island Plutonic Suite.
Locally, andesitic to basaltic flows, bedded tuff, massive tuff, lapilli tuff and tuff breccia of the Bonanza Group are intruded by diorite, quartz diorite and quartz feldspar porphyry of the “Red Dog” porphyry stock (Island Plutonic Suite). On the northeast side of the property, the Bonanza rocks are metamorphosed to hornblende-biotite hornfels in contact zones with silicification and hydrothermal alteration in shear zones. On the southwest side, the Bonanza rocks have either been intensely silicified and brecciated or show alteration to pyrophyllite, pyrite, sericite, zeolite and kaolinite. Abrupt differences in alteration appear to be related to a series of east-orientated normal faults that down-step stratigraphy and alteration to the south.
Two zones of mineralization, referred to as the Red Dog and Slide zones, have been identified in altered Bonanza volcanics along the southern contact of the Red Dog porphyry stock. Alteration immediately south of the intrusive, over distances of 100 to 300 metres, varies from potassic to intermediate argillic and consists of biotite and hydrothermal magnetite with overprinting of chlorite and sericite. The alteration zone contains variable amounts of pyrite and chalcopyrite with minor bornite and molybdenite. Further to the south, potassic and intermediate argillic alterations are in contact with advanced argillic alteration containing pyrophyllite, dickite, silica and pyrite.
At the Red Dog zone, a quartz magnetite breccia hosted by Bonanza Group rocks and adjacent to feldspar porphyry dikes hosts sporadic chalcocite, bornite, chalcopyrite and molybdenite mineralization.
The Slide zone, located approximately 400 metres east of the Red Dog zone, is hosted by altered Bonanza Group rocks with biotite hornfels and local sericite-chlorite overprinting. Mineralization consists of disseminated and fracture-filling pyrite and chalcopyrite. Molybdenite occurs along joints, fractures and in quartz-sericite veins associated with shear zones. Northeast-trending, steeply dipping, late trachyte dikes cut the mineralization.
In 1982, diamond drilling yielded intercepts of 0.325 per cent copper, 0.005 per cent molybdenum and 0.35 gram per tonne gold over 60.0 metres in hole EC-131; 0.362 per cent copper and 0.56 gram per tonne gold over 37.8 metres in hole EC-132; 0.330 per cent copper and 0.53 gram per tonne gold over 120.0 metres in hole EC-132A; 0.285 per cent copper and 0.36 gram per tonne gold over 72.0 metres and 0.426 per cent copper, 0.013 per cent molybdenum and 0.60 gram per tonne gold over a 42.0 metres in hole EC-133; 0.494 per cent copper, 0.012 per cent molybdenum and 0.96 gram per tonne gold over 22.2 metres in hole EC-135 and 0.555 per cent copper with 1.2 grams per tonne gold over 37.8 metres in hole EC-143 (Assessment Reports 10982 and 11048).
In 1988, drillhole 88-1A averaged 0.44 per cent copper and 0.48 grams per tonne gold over 146 metres (George Cross News Letter #183, 1988). Other drillholes yielded intercepts of 0.611 per cent copper and 0.60 gram per tonne gold over 71.4 metres (hole 88-2) and 0.334 per cent copper with 0.24 gram per tonne gold over 39.0 metres (hole 88-4; Assessment Report 18023).
In 1990, diamond drilling yielded intercepts of 0.33 per cent copper with 0.32 gram per tonne gold over 12.0 metres in DDH 90-2; 0.39 per cent copper with 0.65 gram per tonne gold over 171.0 metres in DDH 90-3; 0.31 per cent copper with 0.45 gram per tonne gold over 110.3 metres in DDH 90-4; 0.31 per cent copper with 1.55 grams per tonne gold over 84.0 metres in DDH 90-9 and 0.35 per cent copper with 0.61 gram per tonne gold over 84.5 metres in DDH 90-10 (Assessment Report 20610).
In 1991, diamond drill yielded intercepts of 0.34 per cent copper and 0.51 gram per tonne gold over 67.6 metres in DDH 91-3; 0.43 per cent copper with 0.67 gram per tonne gold over 83.0 metres in DDH 91-5; 0.61 per cent copper with 0.75 gram per tonne gold over 87.0 metres in DDH 91-6 and 0.51 per cent copper with 0.56 gram per tonne gold over 151.0 metres in DDH 91-8 (Assessment Report 21352).
In 2016, diamond drilling of the Red Dog zone, in areas of previous drilling, yielded intercepts of 0.31 per cent copper with 0.47 gram per tonne gold over 198.5 metres in hole RD16-01, 0.33 per cent copper with 0.52 gram per tonne gold over 146.0 metres in hole RD16-02, 0.30 per cent copper with 0.55 gram per tonne gold over 70.8 metres in hole RD16-03 and 0.30 per cent copper with 0.41 gram per tonne gold over 122.0 metres in hole RD16-06 (Assessment Report 36316).
In 1992, drill-indicated, mineable openpit reserves were 25 million tonnes grading 0.35 per cent copper, 0.44 gram per tonne gold and 0.006 per cent molybdenum (MDAP - Crew Natural Resources, Prospectus, 1992).
During 1965 through 1976, programs of soil and rock sampling, geological mapping, ground geophysical surveys and at least 24 diamond drill holes were completed on the area. In 1977, BHP-Utah Mines completed six diamond drill holes, totalling 906.0 metres, on the Expo and Hep claims to the southeast.
In 1982 and 1983, BHP-Utah Mines completed programs of rock and soil sampling, a ground induced polarization survey and 17 diamond drill holes, totalling 2502.5 metres, on the area. In 1988, Crew Natural resources Ltd. completed four diamond drill holes, totalling 1041.8 metres. Also at this time, Moraga Resources Ltd. and BHP-Utah Mines completed a program of geological mapping and rock sampling on the area. In 1989, a further program of rock and soil sampling, geological mapping and seven diamond drill holes, totalling 764.4 metres, were completed. In 1990 and 1991, Morega Resources Ltd. and Crew Natural Resources completed 19 diamond drill holes, totalling 3091.5 metres, on the area.
In 1997, Jordex Resources Inc. completed a 156.1 line-kilometre airborne geophysical survey on the area on behalf of Moraga Resources Ltd.
In 2005, Luminar Resources Corp. completed a program of rock, silt and soil sampling, geological mapping, a 2687.0 line-kilometre airborne electromagnetic survey and 18 diamond drill holes, totalling 3154.0 metres, on the area.
In 2015, Northisle Copper and Gold Inc. optioned the Red Dog property and completed a program of rock and soil sampling and geological mapping. The following year, seven diamond drill holes, totalling 1112.1 metres, on the property. This work confirmed historical drill results and indicated that the main intrusive phase associated with mineralization was the ‘Rose’ porphyry, which is a granite porphyry. Other drillholes to test for a deeply buried porphyry system to the south and southeast were unsuccessful, with drillholes being lost in a major west-striking fault zone.
In 2017, North Isle Copper and Gold Inc. conducted a program of prospecting and spectral analysis to the east of the known zones of mineralization as the Red Dog East property. Later that year, six diamond drill holes, totalling 1848.0 metres, were completed on the North Island property. The lone drillhole on the Red Dog zone was lost short of the target depth.