The Willow Grouse past-producer is located is located on the north western slope of Mount Maguire, approximately 3 kilometres south east of Sooke.

The area is underlain by the Eocene Sooke Gabbro, which forms the basement of the Metchosin Volcanics and is composed of coarse-grained gabbro with about equal parts of bytownite and diopside and about 5 per cent olivine. dikes of leucogabbro contain up to 80 per cent bytownite. Local agmatization, amphibolitization and mineralization of the gabbro occurred later along shear zones.

Chalcopyrite with minor amounts of pyrite, pyrrhotite, magnetite and molybdenite are disseminated in a major shear zone that strikes from 040 to 050 degrees and is about 18 metres wide. It can be traced for more than 600 metres and shows on the surface as subparallel cliffs or scarps. Veins of coarse hornblende are abundant in the main workings, and hornblendite occurs at other places along the shear zone.

In the main zone there are several fissures and subsidiary shear zones, within which occur zones of enrichment varying from 1.5 to 6 metres in width. Copper values average about 8 per cent with a maximum as high as 18 per cent. The most important of these zones occurs on the Willow Grouse Crown grant where the mine workings are located. The length of this zone is about 45 metres and the width of the high-grade orebodies, of which there are three, are 1.8 metres, 4.6 metres and 6 metres, respectively. The general strike of these fissures is 040 degrees and the dip is about 70 degrees; but there is one fissure which strikes 177 degrees and dips 80 degrees that forms a junction with the others near the southern end of the mine workings and carries the richer portion of the orebodies.

The zone has been explored over a length of about 300 metres by an adit, a shaft and several opencuts and trenches. From 1915 to 1918, 1,282 tonnes of ore were mined, from which was produced 61,402 kilograms of copper, 8,740 grams of silver and 280 grams of gold (Mineral Policy data). The high-grade lenses have apparently been completely mined out.

A sample of massive chalcopyrite in altered mafic rock assayed 11 per cent copper, 0.30 per cent nickel, 0.30 per cent cobalt, 0.20 molybdenum and 0.2 per cent zinc (Huestis, 1948). Palladium ranges from trace up to 1.37 grams per tonne and gold and silver values run up to 0.34 and 8.57 grams per tonne respectively (Page, 1950).

In 1951, programs of geological mapping and ground geophysical surveys were completed on the area as the June, Lorna, Moffat and Pac claims.