The Charlemont occurrence is located 25 kilometres southwest of Invermere in the Golden Mining Division. The occurrence is between Coppercrown and Toby creeks on the north face of Coppercrown Mountain.
The area is underlain by Proterozoic clastic sedimentary rocks and Cretaceous intrusive rocks. The occurrence is within the Dutch Creek Formation of the Proterozoic Purcell Supergroup. The Purcell Supergroup strata include the Aldridge, Creston, Kitchener, Dutch Creek and Mount Nelson formations (Paper 1990-1).
In the vicinity of the occurrence, rocks of the Kitchener and Dutch Creek formations have been further subdivided and assigned to the Van Creek and Gateway formations (Open File 1990-26).
The Dutch Creek Formation includes green and black laminated argillite, quartzite, siltstone and buff dolomitic siltstone. The Van Creek Formation consists mainly of coarse to medium grained, light grey to dark green quartzite, siltstone and silty argillite and correlates with the strata of the Lower Kitchener Formation.
The Gateway Formation consists of an interbedded sequence of quartzite, green siltstone and buff dolomite that correlates with the lower portion of the Dutch Creek Formation. The contact with the underlying Van Creek Formation is gradational or marked by the basaltic flows of the Nicol Creek Formation. The sedimentary rocks have undergone regional metamorphism to at least greenschist facies.
At the Charlemont occurrence, the Dutch Creek Formation which hosts the occurrences, consists of northwest trending, isoclinally folded, buff to cream coloured dolomite, siliceous dolomite and grey to black argillite crosscut by north-northwest trending shear zones.
Mineralization is of two principal types. The first of these consists of galena, sphalerite and tetrahedrite in quartz-carbonate veins which occur along steeply dipping, northwest-trending shears. This structure has been exposed through a series of trenches, pits and three small adits. The mineralized vein ranges in width from 0.1 to 1.0 metre. Surface trenches traced the mineralization for 70 metres laterally and 30 metres vertically. Near the surface, the vein material is very oxidized and stained with malachite and azurite. Fine-grained galena occurs as 2 to 10 centimetre wide vertical seams within the quartz-carbonate vein. Sphalerite occurs as fine euhedral disseminated grains within the gangue.
Adit 1 extends for 18.5 metres along a 25 centimetre wide shear hosting a quartz-carbonate vein. Adit 2 extends for 5 metres and is driven on the same structure as adit 1 but here the mineralization is as two conjugate veins, a 60 centimetre wide quartz vein at the portal and a 50 centimetre vein near the face. Adit 3 is caved but it is believed to be driven off the same structure as the other two adits (Assessment Report 13657).
The second type of mineralization consists of galena with abundant malachite and azurite staining on joint and fracture planes in blocky grey-green dolomite. This mineralization occurs 50 metres southwest of the vein exposed in the adits. The structure is at the contact between argillite and dolomite. It has been followed along strike for 120 metres and has an average width of 1.5 metres. A 1.5 metre channel sample across the best section of the mineralization assayed 120 grams per tonne silver and 3.65 per cent lead (Assessment Report 13657).
A total of 12 tonnes mined from the adits in 1907 produced 26,780 grams of silver and 5555 kilograms of lead.