The Billy Mack showing is located on Morley Creek on the south slope of Wilauks Mountain, 5.0 kilometres east-northeast of Alice Arm. The area has been extensively explored for zinc and silver in the past.
The region is underlain by an assemblage of volcanics and sediments comprising the Upper Triassic Stuhini Group, the Lower Jurassic Hazelton Group and the Middle Jurassic to Upper Cretaceous Bowser Lake Group. This assemblage has been folded into a north-northwest trending anticline (Mount McGuire anticline) and regionally metamorphosed to greenschist facies.
The Billy Mack showing comprises various occurrences hosted in Stuhini Group calcareous argillite on the west limb of the Mount McGuire anticline. The main showing consists of a banded vein, 4.6 to 6.1 metres wide, with inclusions of brecciated argillite. The vein strikes northeast for 76 metres along a bluff on the south side of a tributary of Morley Creek and dips 30 degrees southeast. Mineralization, best developed within 1.2 to 1.5 metres of the footwall, consists of sparse streaks of sphalerite and minor pyrite in a gangue of quartz and calcite.
About 100 metres to the northeast, a nearly horizontal 3.7 metre wide body of quartz and calcite outcrops on either side of the tributary. The vein, also containing brecciated fragments of argillite, dips 20 to 25 degrees east and strikes north. Mineralization consists of sphalerite and it is likely that this vein was on the Maple Leaf and Kent claims in 1918. North of the main showing and about 37 metres below it in the creek bottom, a 2.4 metre wide banded and brecciated vein is exposed in a trench. The vein, striking 068 degrees and dipping 55 degrees north, is mineralized with sphalerite and pyrite. A grab sample assayed nil gold, nil silver and 4.0 per cent zinc (Minister of Mines Annual Report 1931, page 39).
In 1931, the property was owned by J. Peacock, T. Calfa, and associates, of Alice Arm. A cabin was situated at 587 metres elevation on the main McGrath Mountain trail. At 542 metres elevation in the creek bottom, a tunnel has been driven about 15 metres on a banded and brecciated vein about 2.4 metres wide in shattered argillite. Not much mineralization was evident in the tunnel, which may possibly be heading northerly of the main structure and reportedly should be turned west or to the left. During the 1931 season this tunnel was continued and encouraging zinc mineralization is reported to have been again encountered.
