The Copper Cliff occurrence is located at an elevation of approximately 1900 metres on a northeast-facing slope approximately 2 kilometres southwest of The Pillar.
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 at the Copper Cliff occurrence, disseminated and stockwork chalcopyrite with minor bornite and pyrite mineralization associated with quartz and alkali feldspar is exposed over an area of 40 by 30 metres of chlorite-quartz-carbonate-sericite–altered lapilli tuff and felspar±biotite porphyritic monzonite. Malachite and hematite staining are also reported in the area. It is suggested that this represents an alkaline porphyry copper-type mineralization in a low-iron, high-copper system (Assessment Report 36861).
Another zone of mineralization, referred to as the Gossan C zone, is near the saddle of a north-south–trending ridge located approximately 400 metres to the northwest.
In 2005 and 2006, four samples (WGR05-A22, WGR05-A23, WG06-A14 and WG06-A15) from the Gossan C zone are reported to have yielded from 0.176 to 0.447 per cent copper, 0.144 to 2.160 per cent lead and 0.051 to 1.330 per cent zinc (Assessment Report 36861).
In 2016, 11 rock samples from the Copper Cliff occurrence yielded from 0.05 to 1.04 per cent copper and 2.8 to 23.9 grams per tonne silver, whereas a rock sample (W16R15) taken downslope from the Gossan C zone yielded 0.355 per cent copper (Assessment Report 36861).
Work History
The area has been historically explored in conjunction with the nearby Atlas East and West (MINFILE 094E 305 and 094E 213) occurrences to the west and the Lar (MINFILE 094E 217) and Black (MINFILE 094E 042) to the east.
During 2015 through 2020, Finlay Minerals Ltd. completed programs of prospecting; geological mapping; rock, silt and soil sampling; an 8.3 line-kilometre induced polarization survey and a 91.0 line-kilometre airborne magnetic survey on the area as the Pil property.