The Otto occurrence is located south of Campbell Creek, approximately 2.3 kilometres east of the north end of Leviathan Lake.

The area is underlain by quartzite and quartz arenite sedimentary rocks of the Lower Cambrian Hamill Group and mudstone, siltstone, shale and fine clastic sedimentary rocks of the Cambrian to Devonian Index Formation (Lardeau Group). These have been intruded by granodioritic rocks of an un-named Cretaceous intrusive to the south.

Locally, galena and sphalerite are reported to occur in small amounts replacing limestone bands (GSC Summary Report 1928). Starr reports that, on the Otto, a shear of considerable width occurs, parallel to the strata and is mineralized with pyrite and a little gold. The shear consisted of a soft gossan with some pyritic streaks. A sample over 90 centimetres from an open-cut assayed 2.74 grams per tonne gold and 30.8 grams per tonne silver (Property File - C.C. Starr [1926-10-15]: Report of Preliminary Examination of the Otto Group).

By 1926, four adits or tunnels had been developed over approximately 200 metres. In 1972, Canex completed a program of soil sampling. In 1979, Esperanza Explorations examined the area as the Step claim.

Later reports, in 1979, describe four adits or tunnels. The no.1 adit is 2.1 metres long in a re-crystallized limestone hosting rusty stained stringers and patches of pyrrhotite and pyrite with lesser sphalerite. The no. 2 adit was collapsed. The no.3 tunnel, extending for 27 metres, is in a re-crystallized carbonate with faint dark banding and some pegmatitic veining with galena-sphalerite seams, some massive, 1 to 15-centimetres wide. The no.4 tunnel is also collapsed but exposes a highly oxidized, 3-metre thick, sulphide layer with pyrrhotite, pyrite and disseminated sphalerite. Limonite and siderite are also reported.