The Pluto showing is underlain by Lower Permian limestone of the Stikine Assemblage.

Base metal veins are 5 to 10 centimetres wide with a strike length of 10 to 15 metres and contain minor pyrite, chalcopyrite and sphalerite. A zone of brecciated limestone has also been noted; the mineralized zone of pyrite and chalcopyrite is less than 1 metre wide with a strike length of 10 metres. Sampling of these occurrences has yielded silver assays up to 418.3 grams per tonne (sample BA-4334), and up to 1.75 per cent copper, 1.77 per cent zinc, and 1.60 per cent lead, and with geochemical values of up to 1000 parts per million arsenic (Assessment Report 18555, 21061).

Refer to Trophy (Ptarmigan) (104G 053) for related details and a common work history.