The Rio claims cover a large area east and south of Spaist Mountain where outcrop is scarce. Mineralization is located mainly on the former Rio 75-80 claims straddling Skuhost Creek (Assessment Report 997).
The area is underlain by Upper Triassic to Lower Jurassic Guichon Creek batholith Bethsaida phase granodiorites. Occasional quartz-orthoclase dikes and one aplite dike have been mapped. Small, isolated diorite, gabbro and pyroxenite outcrops occur to the southwest in Chataway variety granodiorites (see Bin 1-28 (Noranda), 092ISW023).
Minor chalcopyrite, bornite and pyrite occur sporadically in epidote-quartz-calcite stringers in fractures. Percussion drilling to the south (holes P3-P5, P7) showed weak propylitic alteration with mostly no mineralization. Minor malachite and pyrite were reported in the first few metres of bedrock in drill hole P5. High feldspar content was noted in drill hole P7, furthest south from mineralized outcrop (Assessment Report 6611).
In 1965 and 1966, Rio Tinto Exploration Ltd. completed programs of soil sampling, geological mapping a ground magnetic survey on the area as the Rio claims. In 1969, High Point Mines Ltd. completed a 52.0 line-kilometre induced polarization survey on the area as the Deb claims.
In 1978, Lorado Mining Corp. Ltd. completed seven percussion drill holes, totalling 514.0 metres, and a 1 line-kilometre seismic survey on the area as the SV property. The following year, Lornex Mining Corp. Ltd. completed a program of trenching, 10 diamond drill holes, totalling 974.5 metres, and 5 percussion drill holes, totalling 74.7 metres, on the SV claims.
In 1982 and 1984, Norsemont Mining Co. Ltd. completed ground magnetic survey on the SV claims. In 1985, Norsemont Mining completed an airborne electromagnetic and magnetic survey on the SV 1-13 claims. In 1986, Teck Ex. completed a 52.5 line-kilometre induced polarization survey on the area as the SV 21-26.