The Jo Anne occurrence is located on the north western slope of Mount Brooks, approximately 500 metres south east of Divers Lake.

Upper Cretaceous Nanaimo Group, Comox Formation sediments unconformably overlie Upper Triassic Vancouver Group, Karmutsen Formation basalt. Diorites of the Late Eocene to Early Oligocene Mount Washington Intrusive Suite have intruded along this contact resulting in some hornfelsing of the sediments and the development of diatreme breccias.

Disseminated to massive pyrrhotite, pyrite and chalcopyrite occur in hornfelsed Comox sandstones and siltstones. Crackled quartz diorite locally contains pyrite, arsenopyrite and chalcopyrite disseminated within the porous matrix of the sill-breccia complex, in association with chlorite, quartz and calcite. This cavity filling mineralization is considered to be epithermal in origin and similar in nature to the gold-bearing mineralization at nearby Mt. Washington (See 092F 116).

In 1984 and 1985, Iron River Resources completed programs of geological mapping, prospecting and rock and silt sampling. Grab samples of mineralized breccia assayed up to 1.0 per cent copper, 12.4 grams per tonne silver and 0.175 grams per tonne gold (sample JA2-849-4; Assessment Report 14595).

In 1986, BP Resources Canada, on the behalf of Iron River Resources, completed a program of geological mapping and rock sampling. A sample (JA2-858-1) of biotite bearing, leucocratic quartz diorite with disseminated, 5 to 10 per cent, chalcopyrite assayed 5.11 per cent copper, 0.116 per cent zinc, 35.9 grams per tonne silver and 0.21 grams per tonne gold (Assessment Report 14889). The location of this sample is unknown.

In 1987, Noranda Mining and Exploration completed a program of airborne electromagnetic and magnetic surveys, geological mapping and rock, silt and soil sampling on the area. A sample of siliceous breccia from the Cliff Breccia zone assayed 1.66 grams per tonne gold and greater than 1 per cent arsenic (Assessment Report 17096).