The O.K. (L.678) occurrence is located at an elevation of 1067 metres on the east side of O.K. Mountain, approximately 2.4 kilometres west of Rossland. The I.X.L. (MINFILE 082FSW116) claim adjoins the O.K. occurrence to the east.
Regionally, the area is underlain by mudstone, siltstone, shale and fine clastic sedimentary rocks of the Carboniferous to Permian Mount Roberts Formation; basaltic volcanic rocks of the Lower Jurassic Elise Formation (Rossland Group) and trachytic volcanic rocks of the Eocene Marron Formation (Penticton Group). The sediments and volcanics have been intruded by syenitic to monzonitic rocks of the Eocene Coryell Plutonic Suite to the west and quartz monzonitic rocks of the Early Jurassic Rossland Plutonic Suite and granitic rocks of the Middle Jurassic Trail Pluton to the east.
The O.K. veins lie within greenstone and altered greenstone of the Lower Jurassic Elise Formation (Rossland Group). The mine workings pass into dark-grey siltstone and sandstone of the Carboniferous to Permian Mount Roberts Formation. These rocks lie adjacent to the northern contact of a body of serpentinite, probably Permian, which trends east and apparently dips steeply to the south. Many small shear zones along this contact suggest that it is an east-trending fault that is terminated by the Eocene Marron Formation on the west and the Jumbo fault on the east. It is reported that the gold-bearing quartz veins in the O.K. mine occur only in the greenstone and siltstone to the north and that those faults that trapped quartz and precious-metal-bearing solutions did not continue from the greenstone into the serpentinite.
A small intrusion of Middle Eocene Coryell biotite-monzonite was intersected in the lower O.K. adit. Mafic and lamprophyre dikes, most of which trend northward, are widely distributed. The lamprophyre dikes (which range up to 3.0 metres in width), occupy faults that cut the greenstone and monzonite, and in some places have slightly displaced the quartz veinlets.
The greenstone is very fine grained, dense and massive rock of dark-green to brownish hue. The original texture has been destroyed by both the development of chlorite and fibrous amphibole and by local silicification and serpentinization. It varies from a highly altered rock with small amounts of serpentine and magnetite to a mottled phase and then a phase that carries abundant, uniform serpentinite and magnetite. The typical massive serpentinite is a very dense black rock with cross-fibre asbestos infilling joints as 0.2-to 0.6-centimetre veinlets and light-green talc has developed in the immediate vicinity of the faults.
The veins are quartz carbonate fissures that range in width up to 0.6 metre and strike east with moderate to steep dip angles to the north. The veins host free gold, often visible to the naked eye, in mineable pockets that are very erratically distributed along the veins. The mineralized parts of the veins pinch and swell and change in attitude. Widths range from a few centimetres to 0.5 metre and up to 2 metres in places. The strongest mineralized zones are less than 100 metres long and have been developed for the same distance up dip. Other sulphides that occur in the quartz and ankeritic carbonate veins are pyrite, chalcopyrite and galena as well as malachite and azurite. Pyrite is widely disseminated in the hostrock.
In 2015, a combined indicated mineral resource for the I.X.L. (MINFILE 082FSW116), O.K. (MINFILE 082FSW117) and Midnight (MINFILE 082FSW119) occurrences was reported at 48 000 tonnes grading 6.0 grams per tonne gold and 3.0 grams per tonne silver with an additional inferred mineral resource of 8000 tonnes grading 7.7 grams per tonne gold and 2.0 grams per tonne silver (Assessment Report 35609).
The O.K. veins were mined in 1909 and from 1933 to 1939. A total of 293 tonnes of ore were mined and 17 916 grams gold, 14 991 grams silver, and 154 kilograms copper were recovered. Former workings include at least three adits, referred to as the O.K. Upper, Middle and Lower adits.
The O.K. claim (Lot 678) was located by J.Y. Cole in June 1892 and Crown-granted in 1896. Underground work by Mr. Cole & associates opened up a large pocket of quartz bearing high-grade free gold. The O.K. Gold Mining Company, a Spokane, Washington, company that was registered in BC in 1895, acquired the property and carried on mining operations until August 1897, when the affairs of the company were ordered to wind up. Most of the old underground workings were driven during the period 1893 to 1896 and include approximately 305 metres of crosscuts, drifts and raises in three adits.
During 1923 through 1944, lessees carried out some exploration work each year in search of the downward continuation of the O.K. veins or the extension of the I.X.L. (MINFILE 082FSW116) veins. In 1953, the O.K. claim was owned by Mrs. J. Pike, of California, and J. Wey and Mrs. Anabelle, of Seattle. In 1953 and 1956, some rehabilitation and exploration work was done by lessee M. Doran. Midnight Consolidated Mines Ltd. was organized in September 1956 to carry out exploration work on the O.K., I.X.L. and Midnight claims. A small amount of drifting was done on the O.K. claim before operations ceased in April 1957.
In 1993 and 1994, Matovich Mining Industries Ltd. completed a program of geological mapping, a 15.0 line-kilometre ground magnetic survey and 16 diamond drill holes, totalling 2210.0 metres, on the area. In 1996 and 1997, Minefinders Corp. Ltd., on the behalf of Matovich Mining Industries Ltd., completed a program of underground rehabilitation, mapping and sampling and seven diamond drill holes, totalling 877.8 metres, on the area.
In 2005, West High Yield Resources Ltd. completed a program of geological mapping and a 11.2 line-kilometre ground magnetic survey on the area. In 2014 and 2015, ground self-potential and VLF-EM surveys were completed.
