The Oro occurrence is a shear zone exposed in a roadcut 300 metres east of Seventynine Creek, 2.8 kilometres southwest of the peak of Mount Crickmer.
The majority of the region is underlain by granodiorite to diorite intrusions of the Jurassic to Cretaceous Coast Plutonic Complex. Roof pendants of the Paleozoic Twin Island Group and Jurassic Harrison Lake Formation occur throughout the area. These are, locally, intruded by aplite and basaltic dikes.
In the area, mineralization was noted to occur in three distinct modes: 1) quartz-pyrite (± chalcopyrite and magnetite) stringers and veins up to 6 centimetres wide in unaltered quartz diorite, 2) quartz-pyrite lenses up to 0.40 metre wide in unaltered quartz diorite and 3) silicified or calc-silicate altered shear zones up to 3 metres wide containing pyrite and trace chalcopyrite.
The shear zone strikes 160 degrees and dips 80 degrees east and hosts sulphidic vuggy quartz veins up to 0.3 metre in width. In 1983, a diamond drill hole is reported to have yielded up to 1.7 grams per tonne gold over 10.05 metres (Assessment Report 16404, page 5). In 1987, a grab sample (9103) of massive sulphide from the shear zone assayed 2.32 grams per tonne gold, 22.4 gram per tonne silver and 0.2097 per cent copper (Assessment Report 16404, page 9).
Another showing, consisting of an extensive quartz vein of uncertain location, likely lying below the shear zone, strikes 125 to 135 degrees for 300 metres and dips 75 degrees southwest. The vein is bounded by a hangingwall of calcium-magnesium silicates and a footwall of slickensided greenstone. Mineralization consists of arsenopyrite, pyrite and chalcopyrite in a gangue of locally vuggy, fine-grained, banded grey and white quartz.
An unknown amount of high-grade, gold and silver production was reported for the 79 Hill and Blue Devil workings in 1938 and 1939. In 1939, a 612 kilogram bulk sample returned 62 grams of gold, 93 grams of silver, 2 kilograms of copper and 7 kilograms of lead. The workings lie in the vicinity of the above showings.
In 1938 and 1939, native gold was mined from the 79 Hill and Blue Devil workings, near the headwaters of Seventynine Creek between Alouette and Stave lakes. Prior to operations closing in 1939, some high-grade shipments were made from the mine. During 1976, the Spanar claims were staked 1500 metres south of Mount Crickmer. An old adit was subsequently relocated and extended approximately 5 metres. An induced polarization survey was also carried out. Between 1981 and 1987, Skyrocket Exploration and Resources Inc. held a large claim block between Stave and Alouette lakes. Exploration revealed spotty gold soil geochemical values; however, later that year a significant gold value was obtained from a major, northeast- trending shear zone. Follow-up sampling and percussion drilling work was done in and around Kearsley Creek in 1984. During 1988 and 1989, soil and rock sampling surveys were carried out on the Oro and Star claims by 007 Precious Metal Inc. In 1995, the area was prospected and sampled as the Crickmer claims. In 2008, the area was sampled and prospected as the Seventy Nine project by Crucible Resources.
