The Rainy showing is close to Granby Bay on Observatory Inlet and near the historical mining town of Anyox.
The region is underlain by a roof pendant, consisting of volcanic and sedimentary rocks, within the Eocene Coast Plutonic Complex. These pendant rocks have been correlated with Middle-Upper Jurassic Hazelton Group rocks and overlying upper Middle to Upper Jurassic Bowser Lake Group sedimentary rocks (Geological Survey of Canada Open File 3453). The Hazelton rocks consist of variably chloritized pillow and massive andesite and basalt with minor mafic tuffs. The overlying Bowser Lake sediments consist of argillite, siltstone and sandstone with minor chert and limestone. There are two observable phases of folding in the area, an initial north-northeast trending phase followed by a later east-northeast trending phase.
The Rainy showing is a 10 metre wide mineralized shear zone that is exposed in a series of pits and cliffs on the southern, southeastern and eastern slopes of a small prominent hill in the area. The remains of an old prospecting/exploration camp probably date back to regional exploration programs of the early 1950s. The general trend of the mineralized shear is northeast; measured orientations have an average strike of 053 degrees with a 65 degree northwest dip. The hostrocks are massive to slightly stretched pillow basalts. However, in the area of mineralized shear (within 20 metres) the pillows are more elongate and stretched along the prominent foliation direction. The shear zone averages 10 metres in width and is characterized by strong sericitization and lesser pyrite. There is a large flat area downslope to the northeast with well-exposed bedrock that shows no evidence of the extension of the mineralized shear. This suggests that it may be cut off to the east by a fault.
The most significant sulphide mineralization is exposed in a trench on the south side of the hill, 30 metres east-northeast of a small pond. Here a narrow (10-15 centimetre wide) quartz vein with pyrite, sphalerite, pyrrhotite and traces of chalcopyrite is localized within the wider shear zone. This material was sampled for assay and yielded 0.2238 per cent zinc, 0.0119 per cent copper, 0.0003 per cent lead, 0.003 gram per tonne gold and 0.3 gram per tonne silver (D.J. Alldrick, B.C. Geological Survey, unpublished data, 1998).
In 2006, Kenrich-Eskay Mining Corp. completed a program of airborne electromagnetic and magnetic surveys, stream sediment and rock sampling, geological mapping and 50 diamond drill holes, totalling 14275 metres, on the area as the Coastal Copper project. Thirteen of the drill holes were completed on the Rainy area. Rock samples of vein hosted quartz and chalcopyrite with abundant malachite staining and trace native copper hosted by chloritized pillow basalts and brecciated basalts from the Lookout/Cashmore South area were reported to have yielded values up to 3.14 and 4.28 per cent copper (Harrison, D., McKinley, S. (2007-06-18): Technical Report on the Coastal Copper Project, Anyox Area).
