The Triune deposit is at the north end of Silver Cup Ridge. It covers the rugged peak and north and easterly facing slopes of Triune Mountain between 2100 and 2600 metres elevation. The Triune (L.5681), Revenge (L.5685), Silver Chief (L.5683), Enterprise (L.5682) crown grants and the Triune No. 1 tenure are in a cirque drained by Triune Creek, a northeasterly flowing tributary of Lardeau Creek. They are southeast of the Free Coinage [082KNW109] which is, in turn, southeast of the past producing Silver Cup mine [082KNW027]. All three properties are part of the same, fault-controlled, vein system.
The Triune was first owned by Messrs. Ferguson Bros., who leased it to Messrs. Lade Bros. and Gunn Bros. in 1900. The latter drove an 18.3 metres long crosscut that encountered the vein at a depth of 21.3 metres below surface and they continued to tunnel on the vein, which was 1.1 metres wide. Annual Reports show that they shipped 91 tonnes of hand-cobbed ore, later valued at "$12/gold", 11143 grams per tonne silver and 25 per cent lead. They shipped a further 86 tonnes the following year, returning "$18/gold", 13714 grams per tonne silver and 50 per cent lead. However, it is unclear how much was actually shipped in each year. The property was acquired by Metropolitan Gold and Silver Mining Company in 1901 and a shaft was sunk. The company also constructed a wire-line tramway from the mine down Triune Creek that year, but it was destroyed by an avalanche the following winter. Nevertheless, the mine saw further development and limited production through to 1905. At that time, the upper tunnel was 32 metres above the lower and a third adit was being driven further down the hill. The two levels were connected by a raise. The owners shipped a total of 424 tonnes of hand-cobbed ore to the Trail smelter between 1901 and 1905. The shipments returned approximately 30.8 grams per tonne gold, between 8571 and 13714 grams per tonne silver, and between 33 and 50 per cent lead. The property also appears to have produced a further 83 tonnes between 1916 and 1918. By then, a fourth adit had been driven and a new tramway had been built. Production came from the top three adits, which were driven into the cirque wall and now are difficult to get at. There is a section through the workings in the annual report for 1919.
Winslow Consolidated Limited owned the Triune property and milled some ore in 1939 and 1940, and A.F. Upton and D.A.Lougheed broke some ore in the #2 and #3 adits the same year. However, there was a legal dispute and it was not shipped. Thereafter, the property appears to have been dormant until Richrock Mines Limited acquired it from Burrard Mining and Devleopment Syndicate, in 1956, and started the next phase of exploration. In the 1960s, the company rebuilt the access road to the bottom adit and resumed trenching the vein. It also arranged for Dolmage Campbell and Associates to map the property, in 1969. The Trout Lake area is underlain by a thick succession of sedimentary and volcanic rocks of the Badshot Formation and Lardeau Group near the northern end of the Kootenay arc, an arcuate, north to northwest trending belt of Paleozoic and Mesozoic strata that is now classified as a distinct, pericratonic, terrane. The arc rocks are bordered by Precambrian quartzite in the east and they young to the west, where they are bounded by Jurassic-age intrusive complexes. They were deformed during the Antler orogeny in Devonian-Mississippian time and were refolded and faulted during the Columbian orogeny, in the Middle Jurassic. A large panel, the "Selkirk allochthon", was later offset to the northeast by dip-slip motion along the Columbia River Fault.
The Badshot Formation is composed of a thick Cambrian limestone that is a distinctive marker horizon in the Trout Lake area. It is underlain by Hamill Group quartzite and it is overlain by a younger assemblage of limestone, calcareous, graphitic and siliceous argillite and siltstone, sandstone, quartzite and conglomerate, and also mafic volcanic flows, tuffs and breccias, all of which belong to the Lardeau Group. The rocks are isoclinally folded and intensely deformed, but only weakly metamorphosed. They occur as intercalated beds of marble, quartzite and grey, green and black phyllite and schist. Fyles and Eastwood (EMPR BULL 45) subdivided the group into six formations (Index, Triune, Ajax, Sharon Creek, Jowett and Broadview) of which the lowermost (Index) and uppermost (Broadview) are the most widespread. The Triune (siliceous argillite), Ajax (quartzite) and Sharon Creek (siliceous argillite) are restricted to the Trout Lake area. The Jowett is a mafic volcanic unit.
The Triune claim straddles a major fault that cuts Lardeau Group strata north and south of Lardeau Creek. The eastern, hanging wall side of the fault is underlain green phyllite of the upper part of the Index Formation and by black, siliceous argillite and phyllite of the overlying Triune Formation. The assemblage is highly folded and deformed, and intruded by irregular, rusty weathering, dykes and plugs of diorite. The footwall side of the fault it underlain by phyllite of the Triune Formation. The rocks are highly schistose. The foliation displays the regional northwest strike and has a moderate to steep dip to the northeast.
The Triune vein is similar to one that hosts the Silver Cup past-producing mine [082KNW027] immediately to the northwest; however, they appear to be on separate but parallel structures. The full extent of the Triune lens is unknown; although it has been developed over 150 metres of strike length and 122 metres of vertical extent. It is exposed on a steep cliff and is hidden by overburden lower in the Triune basin. The vein is in a band of dark, siliceous slate that is bounded to the northeast by a massive greenstone unit and related phyllite. On the southwest side, it is bordered by grayish-green phyllite and carbonate altered black phyllite similar to that found southwest of the Silver Cup vein. The Triune vein consists of quartz and siderite with variable amounts of galena, pyrite, sphalerite, tetrahedrite and chalcopyrite. It is 0.61 to 2.44 metres wide, strikes 130 degrees and dips at 65 degrees to the northeast and contains mineralized shoots that rake steeply to the northeast. The main productive zone is 27.4 metres long and 3.0 metres wide and the upper workings were designed to exploit a lens 12.19 to 15.24 metres long and 1.22 to 1.52 metres wide shoot down to a depth of 61 metres.
Adit No. 1 was driven at 2331 metres elvation for 114.3 metres and is now closed. It encountered the vein at a depth of 21.3 metres below surface. At that elevation it was 1.07 metres wide and composed of three parts. It had a, 0.61 metre wide, low-grade core zone of honey-combed quartz and carbonate sandwiched between two high-grade zones enriched in galena and tetrahedrite. The hangwall zone was 0.15 metre wide and the footwall zone was 0.3 metre wide. Adit No. 2 is at 2299 metres elevation. It follows the vein for 86.9 metres and has 33.5 metres of crosscut. It encountered a large body of lower-grade mineralization. The average grade of about 31.7 tonnes of hand sacked and hand cobbed "middlings" from the No 2 portal is reported to be 17.14 grams per tonne gold, 1440 grams per tonne silver, 15 per cent lead and 6 per cent zinc. Old reports indicated that the vein assayed 0.17 grams per tonne gold and 668.6 grams per tonne silver over 1.83 metres on this level. Adit No. 3 is at 2252 metres and is 155 metres long. It too is inaccessible. There is a sub level between 3 and 4 and a raise connecting level 3, through the overlying workings, to the surface. These have also collapsed. Adit No. 4 is at 2211 metres elevation. It is 200 metres long may not have intersect the Triune vein. It may have cut a parallel structure, the Enterprise vein, instead. This bottom adit was in good condition in 1970. To the northwest of Adit No. 4, the Triune vein is covered by talus and may be cut by an intrusion.
There are three other veins in the area; however, they are largely covered by overburden. The Bullwheel vein is a rusty quartz zone that contains pods of pyrite and galena. It has been opened up by three adits connected by a raise. The Silver Cup vein has been traced into the Triune basin, where it is partially cut out by a diorite intrusion. The vein should be 30 metres into the hanging wall of the Triune vein. The Enterprise vein shows up as a quartz stringer zone 76.2 metres northwest of the No. 4 adit and may be exposed in it. It contains pyrite but is otherwise barren.
