The Gertrude showings are between 1900 and 2000 metres elevation on the east slope of Lake Creek, which flows to the south into the Lardeau River at Poplar Creek. The Gertrude (L.6804), and adjacent Jane (L.6806), Copper Queen (L.6807) and Free Milling (L.6808) claims were accessed by a trail that went up Sob (A.K.A. Gertrude) Creek, a tributary of the Duncan River, and over the divide into the Lake Creek drainage.
Gertrude tenure was expored by Gold Hills Exploration and Development Company in 1899. However, there is little record of the early work. The ground appears to have been covered by the Mabel, Maude, No.2 and Gertrude claims in 1926. By 1985, these tenures had also lapsed and a new set of Gertrude claims were staked by Silver State Resources Limited.
The Trout Lake area is underlain by a thick succession of sedimentary and volcanic rocks of the Badshot Formation and Lardeau Group near the northern end of the Kootenay arc, an arcuate, north to northwest trending belt of Paleozoic and Mesozoic strata that is now classified as a distinct, pericratonic, terrane. The arc rocks are bordered by Precambrian quartzite in the east and they young to the west, where they are bounded by Jurassic-age intrusive complexes. They were deformed during the Antler orogeny in Devonian-Mississippian time and were refolded and faulted during the Columbian orogeny, in the Middle Jurassic. A large panel, the "Selkirk allochthon", was later offset to the northeast by dip-slip motion along the Columbia River Fault.
The Badshot Formation is composed of a thick Cambrian limestone that is a distinctive marker horizon in the Trout Lake area. It is underlain by Hamill Group quartzite and it is overlain by a younger assemblage of limestone, calcareous, graphitic and siliceous argillite and siltstone, sandstone, quartzite and conglomerate, and also mafic volcanic flows, tuffs and breccias, all of which belong to the Lardeau Group. The rocks are isoclinally folded and schistose but only weakly metamorphosed. They strike to the northwest and dip steeply to the southwest.
The Gertrude area is underlain by schist and quartzite of the Marsh Adams Formation, Badshot limestone, and phyllite of the overlying Index Formation. The Badshot limestone is massive and thick bedded and, near its base, it has highly deformed elongated lenses of sericite-chlorite schist incorporated in it. These lenses are stratabound and locally highly pyritic, and Silver State Resources explored them for "massive sulphide". There is a 15.24 metres deep shaft and a caved adit on one of the pyritic lenses. In 1985, the company collected a channel sample across 2.0 metres of highly oxidized massive pyrite at the top of the shaft. It assayed 3.19 grams per tonne gold, 48.0 grams per tonne silver, 0.04 per cent lead and 0.03 per cent zinc. Samples from the dump assayed up to 12.1 grams per tonne gold.
Silver State also explored an undeformed shear-hosted quartz and carbonate vein that contains irregular lenses and disseminations of galena, chalcopyrite and sphalerite. The vein is 0.2 to 0.75 metre wide and was developed by a shallow shaft and several open cuts. The dominant sulphide in the vein is galena, which occurs as fine-grained seams, as cavity fillings and as course euhedral grains. Chalcopyrite occurs as irregular blebs within galena and is, in most cases oxidized to malachite or asurzite. Cavities are an important feature of the vein. They are filled with bands of galena and elongate ehuedral quartz crystals and indicate several episodes of mineralization in a near surface environment (EMPR ASS RPT 13937). Samples collected from trenches assayed up to 4.56 grams per tonne gold, 250 grams per tonne silver, 14.75 per cent lead, 0.98 per cent copper and 0.15 per cent zinc over the width of the vein. Limited soil geochemistry suggests that the vein has a strike length of at least 100 metres.
