The Joker prospect area is underlain by strongly jointed Iron Mask Hybrid unit diorite breccia and Cherry Creek unit diorite, monzodiorite and monzonite, of the Late Triassic-Early Jurassic Iron Mask batholith. Alteration is weak within the diorite breccia with variable concentrations of fracture-controlled epidote and carbonate. Moderate chlorite alteration is present throughout the unit. Albite is variable and ranges from locally moderate pervasive to absent. Mineralization is weak and erratic and consists of local pyrite, chalcopyrite and malachite. The Cherry Creek unit rocks also exhibit weak fracture-controlled epidote, carbonate and chlorite alteration. Potassic alteration is concentrated in the Joker adit area where disseminated mineralization consists of malachite, chalcopyrite, chalcocite, pyrite and bornite concentrated in a low angle fault and fracture system. Native copper was reported in 1955 diamond drilling by Commercial Minerals Limited. Local malachite and chalcopyrite mineralization and sporadic potassium feldspar and epidote alteration is found along the 200 metre plus long trench cut into the bank of Anderson Creek south from the adit. The average of six 0.5-metre chip samples over a total length of 3 metres from the Joker adit yielded 2.2 per cent copper (Assessment Report 6717).

Drilling in 1955 by Commercial Minerals Limited in a small area to the west of the Joker adit has indicated about 68,032 tonnes grading 0.6 per cent copper. The tonnage estimate is based on eighteen drillholes. Native copper and chalcocite is associated with specular hematite lenses. The zone occurs as a gently dipping zone of intense chlorite-albite alteration in syenodiorite. The zone averages 106 metres long, 36 metres wide and of varying thickness (Report by J.B. Prendergast, 1969 and C.F. Millar, 1966).

In 1955, Commercial Minerals Limited conducted a program of 1676 metres of diamond drilling and minor bulldozer trenching in the vicinity of the Joker adit. In 1965, Mineral Mountain Mines Ltd. completed 18 kilometres of magnetometer survey and 13.2 kilometres of VLF-EM survey on the Bee group of claims. In 1966, Fidelity Mining Investments Ltd. conducted a 21 kilometre induced polarization survey over the Pinnacle claim group which also covered the And (092INE124), Joker and Grey Mask (092INE016) showings. In 1968, Pinnacle Mines Limited took 1785 soil samples over the A, C, Cle and Pin claims which also covered the And, Grey Mask and Joker showings. In 1969, Pinnacle Mines Ltd. completed eight diamond-drill holes totalling 1111.9 metres to test induced polarization anomalies and surface showings; no report was filed. In 1972, geological mapping, soil sampling and 15.9 kilometres of ground magnetometer survey was undertaken on the large holding of JD claims on behalf of Flagstone Mines Ltd. The JD claims also covered the Joker, Grey Mask and And showings. In 1977, Cominco Ltd. conducted geological mapping and rock sampling on the Lark claims. In 1978, Cominco Ltd. completed 6.5 kilometres of induced polarization and ground magnetometer survey over the And/Lark claim group. In 1994, Teck Corporation completed six diamond-drill holes totalling 690.7 metres, 21 kilometres of VLF-EM and ground magnetometer surveys, geological mapping and soil sampling (389) on the Joke and Ace claims which cover the Joker, Grey Mask and Phil showings.