Yellow Bluff is a steep, north trending gossanous cliff with 330 metres of vertical relief above the Taku River, approximately 9.5 kilometres upstream from the confluence of Taku and Tulsequah Rivers and 98 kilometres south of Atlin, B.C.
The Yellow Bluff consists of volcanic rocks altered and impregnated with sulphides (Geological Survey of Canada Memoir 248, page 55). Pyritic massive sulphide lenses are reported to occur with variable copper, lead, zinc, gold, and silver values that are associated with felsic volcanic rocks. The area stratigraphy has recently been reassigned to the Early Eocene Sloko Group and consists of andesitic feldspar porphyry flows and tuffs, coarse sediments to conglomerates, rhyolitic to dacitic flows and tuffs and coarse volcaniclastic and pyroclastic volcanic rocks. The strata across the bluff area strike at about 325 degrees. A Tertiary granitic dike strikes east-west through the strata.
In 1980, prospecting and a geochemical survey was conducted on the Yellow Bluff by Redfern Resources Ltd. and Comaplex Resources International Ltd. The Mud claim had been staked to cover a large pyritic alteration zone megascopically similar to the footwall alteration zone at the Tulsequah Chief Mine situated 9 kilometres to the northwest. Lintott describes a 1982 helicopter-borne, time-domain electromagnetic survey of the Yellow Bluff area which was completed for owner Comaplex Resources (Assessment Report 10719). The report identified a six-channel response as a probable massive sulphide located at the top of the cliff face. The cause of this anomaly which may reflect a concentration of massive sulphides, has not yet been explained. A 1987 exploration program of prospecting and mapping was initiated on Yellow Bluff by Northwind Ventures Ltd. who held the area as part of their Ericksen-Ashby option (Assessment Report 17310). An attempt was made to sample the entire section but because of the very siliceous rock, anchors could not be secured. Narrow sections of massive pyrite were encountered near the contact of the altered intrusion and rhyolite. This contact was interpreted as the potential cause of the six-channel anomaly previously mentioned. Rhyolite containing 5 to 10 per cent pyrite in fractures yielded an anomalous 0.52 parts per million silver. In 2006, Optima Minerals Inc. flew a geophysical crew in to conduct an induced polarization (IP) survey and limited prospecting. A chargeable high was found by the survey and was interpreted to be sulphide mineralization at 50 to 60 metres depth (Personal Communication, D. Mark, 2008).
In 2008, Optima Minerals completed a Mobile Metal Ion (MMI) soil survey that consisted of 99 samples carried out over two small grids within the northern part of the property. Samples were picked up every 25 meters on six lines, three to each grid, for a total of 2740 meters. The MMI survey revealed two anomalous zones that have been labeled A and B. Both anomalies appear to strike northeasterly and are anomalous in zinc, silver, lead, and cadmium that correlate with IP highs. A is also anomalous in copper. Anomaly A is the main high containing the strongest MMI results, especially zinc. The correlation therefore suggests that the mineralization extends in a northeast direction for a minimum 275 meters being open in both the northeast and southwest directions. Anomaly B appears to be parallel to anomaly A having a similar strike length of 250 meters.
In 2012, Optima Minerals Inc. had an interpretation done on the results of government-funded regional geochemistry sampling, specifically stream sediment type, that occur on and around the Yellow Bluff Property, as well as government-flown gravity surveys over the property (Assessment Report 34484).
