The Yuill vein is down slope from the Silver Cup [082KNW027] deposit. It is at approximately 1500 metres elevation on the west side of Cup Creek, which flows into Lardeau Creek. It is northwest of the Towser [082KNW028]. It appears to be on the lapsed Green State (L.4580) crown grant.
Not much is known about the early development of the property; however, George Yuill exposed the vein by sluicing in 1906. It was on strike with that at the Silver Cup [082KNW027] and, at that time, it was believed to be the same vein. There was some work done on the property by C.T. Porter of Spokane, in 1915. The partnership still owned the property in 1929 but it was still largely undeveloped.
In 1972, the Yuill, Towser [082KNW028] and Silver Cup [082KNW029] properties were part of a large land holding owned by True Blue Explorations Limited. The company exposed the Yuill vein by bulldozer trenching but did a limited amount of work on the property. In 1976, C.T. Exploranda Limited acquired the Yuill and Towser properties for its "Silver Chalice" Group. In 1978, it drove an adit on the Yuill at 1500 metres elevation. The workings comprised a crosscut of 84 metres and a drift of 200 metres along the vein. A 50.3 metres long section of the vein was reported to 1.85 grams per tonne gold, 411 grams per tonne silver, 2.96 per cent lead 3.17 per cent zinc across 0.91 metre. In 1981, the company reported a drift-indicated "probable" resource. The company diamond drilled the Yuill and Towser veins on the Y 1500 level and later drove a crosscut towards the projected location of the Silver Cup vein, which was thought to lie to the southwest. Goldfever Resources Limited took over and continued to explore the property in 1985. At that time there were reported to be five high-grade lead-zinc-gold oreshoots. The company raised on the No. 4 shoot and exposed a zone of "massive sulphide". A bulk sample was processed at the David Mineral's concentrator at Ainsworth and a shipment of 13.15 tonnes of concentrate was later sent to the smelter at Trail. It assayed 20.85 grams per tonne gold, 3622 grams per tonne silver, 0.57 per cent copper, 20.9 per cent lead and 19.7 per cent zinc. 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 Yuill claim is underlain by black siliceous argillite of the Triune Formation. The rocks are isoclinally folded, deformed and schistose and they conform to the regional northwest strike and moderate to steep northeast dip prevalent throughout the Silver Cup Ridge area. In 1929, the vein was described as being a quartz vein with a strike of 145 degrees and a dip of 70 degrees to the northeast. It was between 0.15 and 0.61 metre wide, and contained a sulphide shoot, 0.025 metre wide, that was principally composed of galena and pyrite. The sulphide was reported to be exceedingly rich in silver, assaying up to 61714 grams per tonne silver. The vein was re-exposed by bulldozer trenching in 1972 and found to be in a 12.2 metres wide zone of pyritic black schist. In 1978, C.T. Exploranda Limited drifted and diamond drilled on the Yuill and Towser veins on the Y 1500 level. Two short holes gave erratic results but the company reported good (up to 6.99 grams per tonne gold and 1373 grams per tonne silver over 0.46 metre) chip sample results across the Yuill vein. In 1985, Goldfever Resources Limited raised on the No. 4 shoot and exposed a zone of massive sulphide mineralization, 0.6 to 0.9 metre wide, which returned grades of up to 17.14 grams per tonne gold and 3428 grams per tonne silver.
In 1981, C.T. Exploranda reported a drift-indicated "probable" resource in four shoots over 0.91 metre of mining width of 6340 tonnes averaging 1.47 grams per tonne gold, 184.1 grams per tonne silver 2.72 per cent lead and 2.56 per cent zinc (R.W. Phendler, in C.T. Exploranda Ltd. Statement of Material Facts, 113/81).
