The NWB (Northwest Breccia) occurrence is located near the head of a small southwest-flowing creek, north of the Finlay River and approximately 6.8 kilometres west of the west end of Budd Lake.
Regionally, the area is situated within a Mesozoic volcanic arc assemblage, which lies along the eastern margin of the Intermontane Belt, a northwest-trending belt of Paleozoic to Paleogene sediments, volcanics and intrusions bounded to the east by the Omineca Belt and to the west and southwest by the Sustut and Bowser basins.
Permian Asitka Group crystalline limestones are the oldest rocks exposed in the region. They are commonly in thrust contact with Upper Triassic Stuhini Group andesite flows and pyroclastic rocks, and marine sedimentary and volcanic rocks of the Lower to Middle Jurassic Hazelton Group. These rocks have been intruded by plutons and other bodies of the mainly granodiorite to quartz monzonite Early Jurassic Black Lake Suite and are in turn unconformably overlain by or faulted against Lower Jurassic calc-alkaline volcanics of the Toodoggone Formation (Hazelton Group).
The dominant structures in the area are steeply dipping faults that define a prominent regional northwest structural fabric trending 140 to 170 degrees. In turn, high-angle, northeast-striking faults (approximately 060 degrees) appear to truncate and displace northwest-striking faults. Collectively these faults form a boundary for variably rotated and tilted blocks underlain by monoclinal strata.
Locally, the area is underlain by undivided Lower to Middle Jurassic Hazelton Group volcanic rocks cut by feldspar porphyry dikes. A zone of argillic to advanced argillic alteration is largely exposed for approximately 1 kilometre in width and 5 to 6 kilometres in length between the NWB and Nub West (MINFILE 094E 242) quartz-alunite showing to the north.
Mineralization consists of chalcopyrite and malachite with gold and silver values associated with quartz, illite, muscovite and montmorillonite alteration minerals; locally, areas contain alunite, dickite or diaspore minerals. The mineralized zone has been identified over an area of approximately 90 metres in width and 225 metres in length. Vuggy silica and barite veins are reported to the east of the mineralized zone.
In 1988, a rock sample (no. 5) from the area assayed 0.10 gram per tonne gold and 4.3 grams per tonne silver (Assessment Report 18161).
In 1995, four talus grab samples (173180, 174957, 174964 and 174965) from the area yielded values from 0.125 to 0.700 gram per tonne gold (Assessment Report 24641).
In 1998, 12 rock samples from outcrop and subcrop yielded up to 1.035 grams per tonne gold, with seven of the samples yielding greater than 0.136 gram per tonne gold (Assessment Report 25908).
In 2003, 13 rock grab samples from the main Northwest Breccia zone yielded up to 1.04 grams per tonne gold and averaged 0.44 gram per tonne gold, whereas a chip sample assayed 0.93 gram per tonne gold over 0.5 metre (Assessment Report 27492). Another rock sample (133812), taken approximately 500 metres to the southwest from an area of argillic to advanced argillic alteration, assayed 0.94 gram per tonne gold (Assessment Report 27492).
In 2017, diamond drilling yielded intercepts of up to 0.182 per cent copper, 0.005 per cent molybdenum and 1.9 grams per tonne silver over 3 metres of hematized, epidote-pyrite-chlorite–altered intermediate porphyry dike with chlorite-magnetite-pyrite±chalcopyrite stringers in hole JY17001; 0.14 gram per tonne gold, 1.9 grams per tonne silver and 0.051 per cent zinc over 27.30 metres of quartz-pyrite–altered feldspar porphyritic andesite flows and interbedded tuffs in hole JY17002 and 0.557 per cent zinc over 88.32 metres, including 1.579 per cent zinc with 0.167 gram per tonne gold over 5.6 metres of chlorite-epidote-magnetite–altered intermediate porphyry dikes hosting stringers and blebs of sphalerite and pyrite in hole JY17003 (Assessment Report 37516).
Work History
In 1980 and 1981, Serem Ltd. completed programs of prospecting; geological mapping and rock, silt and soil sampling on the area as the Nub Mountain 1-5 claims. During 1987 through 1989, Toodoggone Gold Inc. completed programs of geological mapping, geochemical (heavy mineral, rock, silt and soil) sampling, trenching and a 248.0 line-kilometre airborne magnetic and electromagnetic survey on the area as the Fine 1-4 claims.
In 1995, Electrum Resource Corp. completed a program of rock sampling and photo-geological interpretation on the area.
During 1998 through 2004, Stealth Minerals Ltd. completed programs of prospecting, geological mapping, and rock, silt and soil sampling on the area as the Nub claims.
During 2016 through 2018, Amarc Resources Ltd. completed programs of soil and rock sampling, geological mapping, 115.0 line-kilometres of ground induced polarization surveying and 1940.0 line-kilometres of airborne magnetic surveying on the area as the Joy property.
