The Raft showing is located about 18 kilometres east of Alberni Inlet and 23 kilometres southeast of Port Alberni.
The area is underlain mainly by basalt, pillowed basalt, basaltic tuff and agglomerate of the Devonian Duck Lake Formation, Sicker Group. The basaltic rocks are intruded by numerous white feldspar porphyritic sills. As well, small bodies of diorite, quartz diorite and granodiorite of the Early to Middle Jurassic Island Plutonic Suite occur in the area. The volcanics have been folded into a north-northwest trending syncline-anticline pair and are cut by a major similar trending regional shear zone up to 400 metres wide.
A quartz filled shear zone in the basalt contains massive pyrite and minor chalcopyrite. A sample assayed 2.08 per cent copper (Assessment Report 14993).
A massive sulphide zone, measuring 0.7 metres wide and 8 metres long, occurs in the basalt, 800 metres north of the mineralized shear zone. It comprises siliceous bands with pyrite and minor chalcopyrite. A grab sample assayed 0.138 per cent copper (Assessment Report 13954). The basalts, which are locally saussuritized, epidotized and chloritized, also contain disseminations and stringers of pyrite. Two outcrop samples assayed 0.15 per cent copper and 0.657 per cent zinc respectively (Assessment Report 13954). These are located 800 metres southeast of the massive sulphide zone. Disseminated pyrite also occurs in dacite sills with associated quartz veins intruding the basalts. A sample assayed 0.43 per cent copper and 5.6 grams per tonne silver (Assessment Report 14993). Gold values have been obtained from float samples.
The area was first explored by Gunnex Ltd. between 1963 and 1966. This work involved regional silt sampling and prospecting. In 1983, Lode Resources completed a program of geological mapping and silt and soil sampling. In 1985 and 1986, a program of geological mapping, prospecting and rock and soil sampling was completed by Vanwin Resources Corporation. A VLF-EM survey was also completed around this time. In 2011, Gold Ridge Explorations Inc. completed a regional program of litho-geochemical sampling, helicopter-borne versatile time domain electromagnetic (VTEM) and aeromagnetic geophysical surveys, totalling 34 square kilometres, on the area as the Columbia Shear property. In 2012 and 2013, Golden Peak Minerals Inc. completed programs of geological mapping, geochemical (soil, rock and silt) sampling and a 24.35 line-kilometre ground magnetometer survey on the area. In 2017, New Point Exploration Corp. completed a program of rock, soil, silt and moss mat sampling on the area as the Columbia Shear property.
