The Gum 1 occurrence is located on the southeastern end of Swansea Ridge, approximately 1.2 kilometres northwest of the junction of the Moyie River and Palmer Bar Creek.

The area is underlain by Helikian Purcell Supergroup rocks and Proterozoic Moyie intrusions. Four structural units were recognized. From top to bottom they are: overburden, cap rock consisting of bedded quartzite and argillite, diabase sill, and a lower sequence of bedded quartzite and argillite. The metasedimentary cap rock that overlies the sill and the metasediments underlying the sill belong to the Aldridge Formation (Helikian Purcell Supergroup). These rocks are predominantly composed of bedded quartzite, biotitic quartzite, and argillite. The rocks generally strike along the length of Swansea Ridge and dip roughly parallel to its northeast-facing slope. A Moyie diabase sill has intruded the Aldridge Formation and lies concordant with bedding. The rock is comprised of interlocking grains of unaltered plagioclase feldspar and hornblende. Two phases are recognized: a coarser grained phase at the top of the formation and a medium- grained phase in the middle and lower sections. The thickness of the sill is consistent across the length of the ridge and averages approximately 60 metres (true thickness).

Locally, a 0.5- to 1.0-metre-wide quartz-calcite vein occurs in the Moyie sill. The vein is mineralized with chalcopyrite, azurite, and malachite. A historic adit, approximately 15 metres long, has been driven along the vein (Assessment Report 21938).

In 1978, Cominco completed a program of geological mapping. In 1987 and 1991, Clifton Associates completed programs of geological mapping, a 24.0 line-kilometre ground magnetic survey, test pitting, bulk sampling and 13 diamond drill holes, totalling 1121.2 metres (Assessment Report 21938).

In 2013/2014, PJX Resources Inc began a large program of gravity and magnetic geophysical surveying to detect dense subsurface features (Assessment Report 34937); surveying continued into 2016 (Assessment Reports 34082, 34937, 35416, 36347). The gravity survey extended 10 kilometres beyond the West Basin property claim boundaries encompassing several MINFILE occurrences including the Smoker (Figure 8, Assessment Report 34082).

Refer to the Vine 1 developed prospect (082GSW050) for related geological and work history details.