The Monarch occurrence is located on the east bank of the Illiance River, about 17 kilometres northeast of Alice Arm. The area has been periodically explored since 1915 for copper, lead, silver and zinc.

The region is underlain by Lower Jurassic Hazelton Group volcanics and sediments situated on the east limb of the north-northwest trending Mount McGuire anticline. These rocks have been regionally metamorphosed to greenschist facies.

The Monarch showing consists of a quartz-carbonate-barite vein hosted in a shear zone in andesitic to rhyolitic sericite schists. The vein strikes 150 degrees for 40 metres and dips 58 degrees southwest. The vein is terminated on its north end by a northeast trending fault and on the south end by a west-striking fault which dips 50 degrees north. The vein varies in width from 1 metre on the north end to 20 metres in the central portion to 3 metres at its southern end.

Mineralization consists of galena, sphalerite, chalcopyrite, pyrite and tetrahedrite as veinlets, blebs and disseminations in a gangue of quartz-carbonate (ankerite or siderite), barite and brecciated wallrock. Resampling of old drill core (1968) resulted in an assay of 21.6 grams per tonne silver, 0.43 per cent copper, 1.09 per cent lead and 1.68 per cent zinc over 19.8 metres (Assessment Report 10115, page 11).

An adit was driven east for 56.7 metres in 1916 and 1918, about 33 metres below the showing, but failed to intersect the vein. Two holes drilled in 1967 are reported to have encountered only minor mineralization (Minister of Mines Annual Report 1967, page 49).