The Jumbo adits are located about 500 metres north and 426 metres lower in elevation than the Sanquhar occurrence (082N 047) on the Tangier River valley side, 4.5 kilometres north of the Trans-Canada Highway and Illecillewaet Station of the Canadian Pacific Railway, 40 kilometres east-northeast of Revelstoke.

Bedrock in the vicinity of the adits consist of northwest striking, flat lying to steeply dipping black to dark greenish slates of the Lower Cambrian and younger Lardeau Group. Mineralization consisting of argentiferous galena and pyrite occurs primarily within a massive, vertical quartz vein ranging from 0.9 to 2.7 metres in width. The vein strikes 140 degrees, nearly parallel to the hostrock.

A grab sample from an adit analysed 1149.7 grams per tonne silver, 5.3 per cent lead and 6.15 per cent zinc (sphalerite is inferred from the assay results) (Assessment Report 14219).