The Lam showing is at the headwaters of Lamont (Nine Mile) Creek, about 8 kilometres west-northwest of the creek's confluence with Whipsaw Creek and 13.5 kilometres southwest of Princeton.

A small elliptical plug of diorite intrudes andesitic flows and agglomerates with minor dacitic tuffs and flows, of the Upper Triassic Nicola Group. The diorite plug is 600 metres long and up to 260 metres wide.

These rocks exhibit weak and erratic epidote and carbonate alteration. Some saussuritization of feldspars and chloritization of host rocks has occurred along fractures.

Pyrite is the most common sulphide, occurring primarily along fractures with limonite, but also disseminated, together with minor pyrrhotite, in the volcanics.

Chalcopyrite forms blebs and fine disseminations replacing mafic minerals in the gabbroic matrix of an intrusive breccia in the diorite plug, and isolated grains on altered fracture planes in the surrounding amygdaloidal and porphyritic andesite. Chalcopyrite is erratically distributed through the area and is of very low grade (less than 0.1 per cent). A sample of intrusive diorite breccia with chalcopyrite contained 0.0118 per cent copper and nil molybdenum (Assessment Report 5338, page 65, sample 8067).