The Big Four occurrence is located 42 kilometres southwest of Telkwa, on a ridge east of the Telkwa River.

Mineralization is associated with quartz veining in a fine- grained granodioritic stock of the Eocene Nanika Intrusions. The contact with Lower Jurassic Hazelton Group volcanics of the Telkwa Formation occurs a short distance to the east. Several quartz veins, varying in width from 0.9 to 2.4 metres strike northwest in a light coloured, fine-grained granitic rock. The veins are mineralized with pyrite, chalcopyrite, galena, and sphalerite. A sample across 0.5 metres of mineralization at the bottom of a shaft assayed trace gold, 68.6 grams per tonne silver, trace copper, 34 per cent lead and 3.0 per cent zinc. About 1.8 tonnes of material was mined from a quartz vein which was fairly well mineralized over a width of 6.0 metres. A selected sample of the best mineralization assayed 0.69 grams per tonne gold, 246.9 grams per tonne silver, 36.3 per cent lead and 2.5 per cent copper (Minister of Mines Annual Report 1926, page 138).

The Big Four area was explored by D. Groot Logging Limited in 1981. This consisted of upgrading access to the property, cleaning out the main three areas of interest and the mapping and sampling of these zones. One of the twenty samples taken returned 3.4 grams per tonne gold, 120.7 grams per tonne silver, 0.14 per cent zinc, 7.3 per cent lead, 0.49 per cent copper; another sample returned 23.3 grams per tonne gold, 105.6 grams per tonne silver, 0.13 per cent zinc, 1.32 per cent lead and 0.41 per cent copper (Property File Rimfire Plecash, 1981).