The Rainbow occurrence is exposed in cliffs and several adits located on the south side of Birk Creek, approximately 2.4 kilometres northwest of the west end of North Barriere Lake.

The area is underlain by metavolcanic and lesser meta- sedimentary rocks of the Eagle Bay Formation of Devonian to Mississippian age. The volcanics include felsic tuffs and flows, metamorphosed to quartz-sericite schists and quartz- chlorite schists. The metavolcanics are intercalated with and overlain by limestone, graphitic argillite and phyllite.

The rocks trend northwest, with a prominent foliation dipping moderately to the southwest, and locally striking east-west with a moderate southwest dip.

Small stocks of fine-grained, porphyritic granodiorite to quartz diorite intrude the metavolcanics. The Cretaceous Baldy Batholith of quartz monzonite to granodiorite composi- tion lies north of the area.

The Rainbow showing is exposed in cliffs and several adits on the south side of Birk Creek. A 3.5 metre sulphide- rich section within generally contorted quartz-eye sericitic schist and carbonaceous quartz schist overlain by sulphide- poor sericite schist. The schists are in fault contact with limestone to the east. The sulphides occur as massive pods, up to 3 metres thick, of pyrite with minor chalcopyrite and as disseminated pyrite, galena, sphalerite and chalcopyrite.

Two other areas of mineralization, referred to as the E and F zones, are located approximately 350 metres west-southwest and 400 metres east of the main Rainbow zone, respectively, on the south bank of Birk Creek. A 15-metre adit located on the E zone is reported to expose a flatly dipping, bleached chlorite schist hosting streaks of pyrite with minor sphalerite, galena and chalcopyrite, up to 0.25 metre thick. A sample from this zone is reported to have yielded 0.68 gram per tonne gold, 0.9 per cent copper, 0.7 per cent lead and 1.3 per cent zinc over 1.0 metre, whereas another sample taken approximately 45 metres west of the adit yielded 27.4 grams per tonne silver, 0.7 per cent lead and 5.7 per cent zinc over 0.25 metre (Property File – unknown [unknown]: Report on the Iron Cap Group).

The F zone has been explored by a short (3.6 metre long) adit that follows a 0.05- to 0.65-metre wide massive to semi-massive band of pyrite with minor chalcopyrite.

During 1938 through 1940, it is reported that 234 tonnes grading 2.0 per cent copper, 57.0 grams per tonne silver and 28.0 grams per tonne gold were shipped from the lower Birk Creek (Copper Cliff [MINFILE 082M 220] occurrence; Assessment Report 21208). Some or all of this production may have come from the nearby Rainbow occurrence and its related workings.

In 1976, a grab sample of a massive pyrite lens assayed 3.08 per cent copper, 0.40 per cent lead, 0.22 per cent zinc and 13.4 grams per tonne silver, whereas a grab sample of the disseminated mineralization yielded 0.30 per cent copper, 0.60 per cent lead, 0.57 per cent zinc and 6.2 grams per tonne silver (Assessment Report 6202). Also at this time, chip samples from adit 7 yielded 0.75 per cent copper over 1.59 metres, whereas a chip sample from adit 6 yielded 0.45 per cent copper and 25.7 grams per tonne silver over 1.68 metres (Property File - Gower, S.C. [1976-11-01]: Geology Map of the Birk 1 and 2 Claims).

In 1978, diamond drilling on the ridge to the south of the Rainbow workings yielded intercepts including 0.30 per cent copper, 0.61 per cent lead, 1.40 per cent zinc and 13.7 grams per tonne silver over 1.0 metre (127.2 to 128.2 metres downhole) of dacite to andesite with chert fragments hosting pyrite and minor chalcopyrite, galena and sphalerite in hole BET-1 and 4.09 per cent copper, 10.6 grams per tonne silver and 0.34 gram per tonne gold over 0.5 metre (103.8 to 104.3 metres downhole) of a quartz vein hosting pyrite and chalcopyrite in hole BET-3 (Assessment Report 6879).

In 1990, a chip sample (VA12362) from the Rainbow occurrence yielded 0.22 gram per tonne gold, 8.4 grams per tonne silver, 0.564 per cent copper, 0.166 per cent lead and 0.302 per cent zinc over 0.60 metre (Assessment Report 21208).

Work History

The area has been explored since the early 1900s, and at least 10 adits and/or tunnels, 5 to 15 metres long, and a 48-metre long adit had been developed by the 1930s.

In 1951 and 1952, Kennco Explorations Ltd. completed programs of bio- and geochemical sampling, a 26.0 line-kilometre ground electromagnetic survey and seven diamond drill holes, totalling 550 metres, on the area as the Johnson property. In 1966, the Mining Corporation of Canada Ltd. explored the area.

During 1969 through 1972, Duncanex Resources Ltd. completed programs of soil sampling, geological mapping, geophysical surveys, trenching and seven diamond drillholes, totalling 711 metres, on the area. During 1976 through 1978, Cominco Ltd. completed a program of rock and soil sampling, geological mapping, trenching, 17.1 line-kilometres of ground electromagnetic and induced polarization surveys and six diamond drill holes, totalling 772.2 metres, on the area as the Bet 1-5 claims.

In 1982, Preussag Canada Ltd. completed a program of geological mapping, geochemical (rock and soil) sampling, a 12.5 line-kilometre electromagnetic survey and a lone drillhole, totalling 120 metres, on the Bet claims.

During 1989 through 1991, Falconbridge Ltd. completed programs of geochemical (rock and soil) sampling, geological mapping, 97.7 line-kilometres of combined ground magnetic, electromagnetic and induced polarization surveys, trenching and at least nine diamond drill holes, totalling 2619.2 metres, on the Bluff, Bet, Mac, Raven, Rust and Percy claims.

During 2005 through 2010, the area was prospected and (rock, silt and soil) sampled as the Stellar claims.