The Dalvenie prospect is located on the east flank of Thenatlodi Mountain, about 32 kilometres southeast of the south end of Dease Lake.
The area of the Dalvenie prospect is underlain by the Upper Triassic to Lower Jurassic Stuhini Group. At the occurrence, the rocks are described as augite and plagioclase porphyry, andesite, basalt, tuff, breccia, argillite, quartzite, shale and minor thin beds of chert. The strata are intruded by an Alaskan-type ultramafic body, the Late Triassic Gnat Lake Ultramafite, consisting of hornblendite, hornblende clinopyroxenite and hornblende gabbro. Monzonitic to syenitic rocks of the Middle Jurassic Three Sisters Plutonic Suite outcrop to the immediate south.
Two parallel basalt dikes occur trending 016 degrees and dipping 75 degrees west. The dikes are about 1 metre thick and separated by 60 to 180 centimetres of sheared material. The dikes occur along a highly sheared fault zone which forms the main mineralized zone. The dikes and the mineralized zone have been traced along surface for 1146 metres. The maximum width of the zone is at least 9.75 metres wide.
The fault zone contains smoky grey quartz with abundant sulphide mineralization observed at three showings. Sulphides present include massive pyrite with blebs of chalcopyrite and arsenopyrite, and smears of bornite and hematite along fractures. Siderite, barite, magnetite, pyrrhotite and sphalerite have also been reported.
The wallrock of the mineralized zone is mainly the ultramafite but in the extreme southern part the wallrock is sedimentary. The wallrock is generally unmineralized but may contain sulphides locally. The basalt dikes are locally mineralized.
A weighted average of six chip samples yielded 1.19 per cent copper over 7.3 metres (Assessment Report 898). Another composite sample taken over 12.5 metres yielded 1.03 per cent copper (Assessment Report 897). A 1.22-metre chip yielded 1.37 grams per tonne gold (Assessment Report 898). A 1968 drillhole reportedly yielded 3.73 per cent copper and 4.80 grams per tonne gold over 1.5 metres (Assessment Report 19885).
The property was first staked in 1899. In 1935, the Dalvenie Syndicate acquired the property and the Dalvenie 2-9, Mac and New Deal 1-4 claims were subsequently Crown granted. Work in 1935 traced the mineralization for 360 metres by means of 13 shallow open cuts. In 1966, Copper Pass Mines Ltd. acquired the Crown grants and staked additional claims. Work completed in 1966 included geological mapping, induced polarization and soil geochemical surveys, trenching and some short X-ray diamond-drill holes. In 2005-06, the Dal 1-4 claims were prospected by G. Diakow, L. Sharp and R. Unrau. Outcrop was mapped and numerous trenches from earlier explorers were located and sampled; over 55 samples were collected and four were sent for analysis.
In 2011, BC Geological Survey crew members identified a polymictic breccia zone along the trace of the Dalvenie shear, and associated mineralization was sampled (Table 2, Fieldwork 2011). Two assay samples were taken about 2 metres apart and show the highly variable metal content of the prospect. A sulphide rich sample (11BVA11-62b) returned values of 0.57 gram per tonne gold, greater than 1 per cent arsenic, anomalous antimony and bismuth and slightly elevated copper and silver; an intensely silicified and sericitized sample (11BVA11-62a) contained 0.0535 per cent arsenic as well as slightly elevated antimony, bismuth and tungsten (Fieldwork 2011, page 114; Table 2, page 112). The survey crew conducted a mapping project in the vicinity of the Dalvenie (Figure 3a, Fieldwork 2011, page 102).
