The Mac copper occurrence is situated on the Mac 51 claim, on a steep, north-facing slope 1 kilometre west of Magnum Creek, 7 kilometres northwest of Mount Roosevelt in the mountainous Muskwa Ranges of the Northern Rocky Mountains (Assessment Report 3535, Map 3; Geology, Exploration and Mining in British Columbia 1971).
The occurrence is in a region known as the Muskwa Anticlinorium, a major north-northwest–trending structure characterized by moderate folding and thrust faulting. The structure consists of Middle Proterozoic (Helikian) rocks of the Muskwa Assemblage, as well as Paleozoic rocks (Geological Survey of Canada Map 1343A; Geological Society of America, Geology of North America, Volume G-2, pages 111, 639). All belong to Ancestral North America (Geological Survey of Canada Map 1713A). Northeast- to northwest-trending Proterozoic diabase dikes are common in the region.
The area occurs in the Aida Formation of the Muskwa Assemblage, which comprises slate, dolomitic and calcareous slate, dolostone and minor limestone (Assessment Report 3535; Geology, Exploration and Mining in British Columbia 1971; Geological Survey of Canada Memoir 373). Rocks in the area are generally folded, but around the showing bedding strikes approximately 280 degrees and dips 15 degrees south. Slaty cleavage strikes northwest and dips moderately southwest. The rocks are intruded by dark-green, fine-grained diabase dikes that range from 1 to 30 metres in thickness. In this area they strike northeast and dip 70 degrees northwest.
The Mac occurrence is centred on a zone of mineralized, quartz vein breccia in silicified sedimentary rocks, at the intersection of a north-northwest–striking shear-hosted vein and a northeast-striking vein-dike system. The breccia zone is approximately 7.5 by 7.5 metres, and is intruded by a network of diabase stringers, demonstrating that, here at least, dike intrusion post-dated veining and mineralization. The breccia is well mineralized with chalcopyrite and lesser pyrite. A 4.5-metre chip sample in the breccia zone assayed 6.18 per cent copper (Assessment Report 3535). The dikes may also be weakly mineralized.
To the north, the mineralization extends along a shear zone for approximately 180 metres as a sheeted, quartz-ankerite vein, 1 to 2 metres wide, with chalcopyrite and pyrite (Geology, Exploration and Mining in British Columbia 1971, page 87). It strikes 350 degrees and dips 70 degrees west. A 0.75-metre chip sample here assayed 1.52 per cent copper (Assessment Report 3535). Still farther north, the vein gets thinner and more sparsely mineralized, before dying out.
The Mac occurrence is on strike with the Magnum Mine zone, 3 kilometres to the north-northeast, but they are apparently not connected (Assessment Report 3535).
Work History
In 1971, Churchill Copper Corp. Ltd. completed a geological mapping program on the area as the Mac, Don and ME claims. In 1979 and 1980, Halferdahl & Associates Ltd. completed a regional program of soil sampling on the area as the Tuchodi property.
In 2005, Twenty-Seven Capital Corp. completed a regionally extensive program of geochemical (rock, silt and soil) sampling and a 9002.0 line-kilometre airborne magnetic survey on the area as the Muskwa property. Also in 2005, Action Minerals Inc. and Aries Resource Corp. completed a program of prospecting on the area as the Lucky Lady claims of the Trident Copper project. In 2006, Bradford Mineral Explorations Ltd. conducted 4467.0 line-kilometres airborne magnetic and electromagnetic surveys on the area as the Trident property.
During 2017 through 2019, Fabled Copper Corp. completed programs of prospecting, geological mapping, rock sampling and a ground electromagnetic survey on the area as the Churchkey property. In 2021, Fable Copper Corp. completed a program prospecting, rock sampling and UAV photogrammetry surveys on the Church-Key-Neil property. Five float samples (D723261 through D723265) from the Mac occurrence area yielded from 4.39 to 19.60 per cent copper (Assessment Report 39913).
