The Castle occurrence is located approximately 20 kilometres east of the community of Dease Lake.
Regional mapping by the Geological Survey of Canada (Open File 2779) shows the Castle area to be mainly underlain by the Lower Jurassic Inklin Formation (Laberge Group) consisting of slate, greywacke, and conglomerate. Rocks of the Upper Permian to Jurassic Kutcho Formation may form part of the strata and these include basaltic to rhyolitic schist (flows, breccia, and crystal tuffs) and fine-grained volcanic sediments. Limestone of the Upper Triassic Sinwa Formation (reassigned to the Stuhini Group) is commonly argillaceous and is exposed locally.
Three types of mineralization have been identified as follows: 1) Finely banded chalcopyrite and sphalerite occur in small carbonate-epidote lenses and bands within a chlorite schist unit. Mineralization is apparently restricted to a zone 3 to 5 metres thick and less than 100 metres along strike. This zone is located on the west bank of Little Eagle River, directly opposite the mouth of Squaw Creek. 2) Small blebs of chalcopyrite and chalcocite occur associated with pockets of remobilized quartz in the area of the rhyolite unit. 3) Disseminated pyrite occurs in both rhyolite and conglomerate.
In 1996, a rock sample (547355) from a siliceous, sulphidic layer in chlorite schist containing chalcopyrite-pyrite as lenses and disseminated blebs yielded 9.33 per cent copper and 6 grams per tonne silver (Assessment Report 25093).
In 2018, two samples (Q932302 and Q932303) were taken from near the junction of the Little Eagle River and Squaw Creek. Weakly anomalous sample Q932302 consists of bleached boxwork after 3-5 per cent pyrite in an altered mafic schist associated with a 3-metre-wide foliation-parallel structure. Sample Q932303 is a select sample taken approximately 40 metres further downstream; mineralization consists of chalcopyrite, sphalerite, and pyrite associated with 3-10 millimetre irregular quartz-carbonate stringers over approximately 1 metre of weak mineralization. Select sample Q932303 assayed 1.26 per cent copper, 3.8 per cent zinc and 4.9 grams per tonne silver (Assessment Report 38012).
The first recorded work was in 1975 when the showings were first described. At that time, Noranda completed soil geochemistry and electromagnetic surveys. Noranda restaked the property in 1985 and did more prospecting and geophysical work. In 1991, the property was restaked and prospected as the Acme claims by M. Archambault. In 1996, the Funken and Groovin (104I 138) claims were staked by Antioch Investments Ltd. followed immediately by limited rock sampling; 27 samples were taken from mineralized float and outcrop.
No further mineral exploration was reported in the area prior to staking and geologic and geochemical studies of the TCS property by Attunga Holdings Inc. and Running Dog Resources Ltd. in 2017. The 2017 exploration program focused on a historic copper-zinc soil geochemical anomaly and a reported copper-zinc showing in Squaw Creek, with the collection of 10 rock samples, 11 silt samples, and 7 soil samples. In 2018, the TCS property was under option by Kutcho Copper Corp. from Running Dog Resources Ltd. and Attunga Holdings Inc. The 2018 exploration program followed up on the 2017 work that identified the claims as having potential to host volcanogenic massive sulphide mineralization similar to the Kutcho (104I 060) deposit 83 kilometres to the east-southeast. A total of 14 rock samples and 197 soil samples were taken.
