The Arallu prospect claim is on Stobart Creek, on the west side of Silver Cup Ridge. Its precise location is uncertain. The trail to the Arallu passes within a kilometre of the Golden Crown [082KNW116] workings.

There is little information available on the Arallu, other than that there was 18.3 metres of tunneling done on the property in 1900, and that the lower adit had collapsed by 1918. 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 allochtho", 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 intensely deformed, but only weakly metamorphosed. They occur as intercalated beds of marble, quartzite and grey, green and black phyllite and schist. Fyles and Eastwood (EMPR BULL 45) subdivided the group into six formations (Index, Triune, Ajax, Sharon Creek, Jowett and Broadview) of which the lowermost (Index) and uppermost (Broadview) are the most widespread. The Triune (siliceous argillite), Ajax (quartzite) and Sharon Creek (siliceous argillite) are restricted to the Trout Lake area. The Jowett is a mafic volcanic unit.

The Arallu prospect is most likely underlain by deformed, grey, gritty, schistose sediments of the Broadview Formation. However, depending on it precise location, the tenure may have covered Jowett Formation mafic volcanic rocks. The rocks in the area are folded and display the northwest-oriented foliation and moderate to steep northeast dip found throughout the Silver Cup Ridge area.

There is no geological data available on the Arallu. However, the presence of a prospecting adit suggests that there was a vein of some description on the property. It most likely contained lead, zinc and silver.