The property lies within the Shuswap Metamorphic Complex along the northwestern margin of the Frenchman Cap Dome. The core of the dome is composed of a mixed paragneiss and orthogneiss succession of probable Aphebian age. The dome is mantled by unconformably overlying metasedimentary rocks consisting of quartzites, calcare- ous schists, marbles and pelitic schists and locally intruded by carbonatite.
The metasediments comprise the limbs of the Grace Mountain syncline, a tight isoclinal fold trending southeasterly.
The mineralized zones occur on both limbs of the syncline within the "Cottonbelt sequence", a heterogeneous package of dominantly calcareous rocks (Fieldwork, 1978). At the base of the Cottonbelt sequence is a buff-weathering carbonatite layer overlain by calcareous schists and a calcareous to relatively pure white quartzite. A distinctive grey-weathering, white limestone overlies the quartzite, which is overlain by interlayered mica- eous and calcareous schists and an impure grey-weathering crumbly limestone. The sulphide layer, enveloped by a thin layer of very siliceous calcareous schist and a garnet sillimanite schist, defines the top of the Cottonbelt sequence.
The stratabound mineralization comprises an oxide-sulphide layer traced intermittently through a strike length of 5 kilometres in the western (upper) limb (Cottonbelt zone) of the Grace Mountain syncline and 2 kilometres in the lower limb (Copper King and McLeod zones). It varies in thickness from a few tens of centimetres to approximately 2 metres. Mineralization generally consists of disseminated to massive coarse-grained sphalerite, magnetite, galena and minor pyrrhotite in a dark green, pyroxene-amphibole-quartz- garnet "skarn" rock or, as layers within a lighter coloured, more siliceous calcareous gneiss or as disseminated grains in a siliceous granular marble.
The McLeod zone lies about 460 metres northeast of the Cottonbelt zone (082M 086). The zone is intermittently exposed for a length of 600 metres. The hanging wall is chiefly dark biotite gneiss and the footwall crystalline limestone. Minera- lized sections of the zone contain galena, sphalerite and magne- tite with lesser pyrite and chalcopyrite. Twenty-one surface chip samples along the exposed length of the zone, returned an average of 5.37 per cent lead, 6.51 per cent zinc, 97 grams per tonne silver across an average of 1.4 metres (Property File Report by Allen, A.R., 1966).
Twenty-one surface chip samples along the exposed length of the zone, returned an average of 5.37 per cent lead, 6.51 per cent zinc, 92 grams per tonne silver across an average of 1.4 metres (Property File Report by Allen, A.R., 1966).
In 1951, a sample taken south east of the Bass shaft assayed 2.80 per cent lead, 2.50 per cent zinc and 68.6 grams per tonne silver over 76.2 centimetres (Williams, J.D. (2012-06-12): Technical Report on the Copper King – Cotton Belt Property).
In 2011, four samples (545640 through 545643) for the area of the Bass shaft yielded values from 4.48 to 19.96 per cent lead, 0.05 to 0.57 per cent zinc and 48 to 171 grams per tonne silver (Williams, J.D. (2012-06-12): Technical Report on the Copper King – Cotton Belt Property).
See Cottonbelt (Minfile 082M 086) for a completed exploration history of the area.
