The Empire occurrence is located at an elevation of approximately 1670 metres on a north-facing slope, approximately 650 metres south of the west end of Calling Lake.
The area is underlain by Bethsaida phase granodiorite to quartz monzonite of the Upper Triassic to Lower Jurassic Guichon Creek Batholith. Ovoid quartz eyes and euhedral biotite "books" with minor hornblende are characteristic. Bethsaida rocks are intruded by quartz-feldspar porphyry dikes up to 30 metres wide and numerous aplite dikes up to 5 centimetres wide. Guichon variety quartz diorite outcrops to the southwest.
Intrusive contacts to the west and regional faulting define a prominent structural trend striking 010 degrees. A distinct second set of shearing strikes 045 to 065 degrees. Mineralization is localized along faulting and is of higher grade and in larger bodies in the latter set. Jointing is well developed and varies in density, being more numerous close to faulting.
At the Empire occurrence, an inclined and a vertical shaft are spaced 24 metres apart in the widest part (60 metres) of an altered shear zone. The altered shear zone pinches and swells along strike for approximately 185 metres. The shear strikes 050 degrees and dips very steeply to the southeast. To the northeast, the zone narrows to less than 15 metres before being obscured by overburden. Alteration associated with fracturing consists of intense sericitization with silicification and widespread malachite staining. Mineralization, primarily bornite with minor chalcopyrite, is structurally controlled and occurs in thin quartz veins and as blebs, fracture-fillings and disseminations in silicified, sericitized porphyry.
In 1956, a channel sample across the mineralized fault zone assayed 2.6 per cent copper over 0.4 metre, whereas chip samples over a 4.5 by 1.65 metre area of fracture-controlled mineralization yielded 0.35 per cent copper (Assessment Report 170).
In 1963, representative samples from the dumps assayed from 0.65 to 1.13 per cent copper (Assessment Report 490).
Several hundred metres to the north of the Empire occurrence and workings, near the common corner of the former Nancy 3,4, 5 and 6 claims, a trench exposes a 15-metre wide zone at the southeast end of the trench, comprising a granodiorite with occasional bands of sericitic porphyry and several small shears. Mineralization comprises chalcopyrite and malachite in narrow quartz veins and stringers, as fracture fillings and in a 38-centimetre wide fault zone.
Work History
An inclined and a vertical shaft, dating to the early 1900s, have been developed on the occurrence. The inclined shaft is reported to be approximately 10.5 metre long, whereas the vertical shaft is approximately 15.6 metres deep. Minor crosscutting was completed in both shafts.
In 1956, Laco Mines Ltd. completed a program of geological mapping and trenching on the area as the Dominion, Nancy, Starnes and Terry claims of the Laco property.
In 1960 and 1961, Royal Canadian Ventures Ltd. completed a program of geological mapping and a ground magnetic survey on the area as the Bon, Call, Cana and Royal claims. In 1963, Buttle Lake Mining Co. Ltd. completed a program of geological mapping and a 2.2 line-kilometre ground magnetic survey on the Empire claim. In 1965, Cominco Ltd. completed a 12.8 line-kilometre ground magnetic survey, geological mapping and trenching on the Nancy, B.L. and Tom claims.
In 1966, Royal Canadian Ventures Ltd. completed a program of geological mapping, soil sampling and a 19.0 line-kilometre induced polarization survey on the area as the Cana, RC and Royal claims. In 1969, Great Plain Development Ltd. completed a 27.0 line-kilometre ground magnetic survey on the claims.
In 1970, Great Plains Development Co. Ltd. completed a 16.3 line-kilometre induced polarization survey on the Royal claims.
In 1980, Cominco Ltd. completed 60.0 line-kilometres of ground magnetometer and induced polarization surveys on the area as the Island property. The following year, 22.9 line-kilometres of induced polarization surveys were completed on the property.
