The Harriet Lake phosphate occurrence is located in a north-trending creek valley, approximately 1.6 kilometres east-southeast of Mount Salter.

Regionally, the area is underlain by a series of generally north-trending sedimentary rocks including dolomitic carbonate rocks of the Mississippian Etherington, Mount Head and Livingstone Formations (Rundle Group) and Pennsylvanian to Permian Rocky Mountain Group, fine clastic sedimentary rocks of the Triassic Spray River Group, undivided sedimentary rocks of the Jurassic Fernie Formation and undivided sedimentary rocks of the Jurassic to Cretaceous Kootenay Group.

Locally, at the Harriet Lake showing, steeply dipping shale and phosphorite of the Jurassic Fernie Formation unconformably overlie siltstone of the Triassic Sulphur Mountain Formation (Spray River Group). The phosphorite is pelletal, has an exposed thickness of 0.55 metre and contains 13.8 per cent P2O5 (Open File 1987-16). It occurs at the base of the Fernie Group.

Work History

In 2023, Fertox International Organic Inc. conducted a minor program of prospecting and rock sampling on the area as part of the Mt. Lyne Trend property.