A number of mercury showings occur along the Pinchi Fault zone. The Pinchi Fault separates the Mississippian to Triassic Cache Creek Group from the Upper Triassic Takla Group. The fault has provided zones of permeability for the passage of mercury-bearing hydrothermal solutions in a number of places along its length. The origin of the mercury mineralization is not yet clear and in many places there are no obvious sources of heat or origin of the metals.
The Calex showings occur within an area underlain by the Mississippian to Triassic Cache Creek Group and Permian to Triassic Trembleur Intrusions. Both groups are represented in the area of the showings.
Mafic volcanics with minor shale and limestone and serpentinized peridotite have been intensely sheared and carbonatized to varying degrees. This carbonatization has, in places, resulted in the formation of massive ferrodolomite, widely replaced by cinnabar. Minor cinnabar is also associated with an erratic quartz vein stockwork.
HISTORY
During the war years carbonatized serpentine float containing cinnabar was discovered south of Murray Ridge on ground that in 1982 was covered by the Midnight claims (Assessment Report 11213). The Murray group of claims was staked in 1941 for The Consolidated Mining and Smelting Company of Canada Limited. Extensive stripping at the time was unable to locate the source of the float.
The D.A. group of 16 claims was located, on the showings by D. Rottackar in 1956, and acquired later in the year by Centennial Mines Ltd., which was controlled by Canadian Exploration, Limited. Later, in 1956, the "Centennial Showing", a zone of carbonate altered rock, was uncovered on the old Manson Creek Road. This showing is on the Midnight 3 claim of 1982, 120 metres south of the new Manson Creek highway. Exploration was carried out both north and south of the old Manson Creek road by Canadian Exploration Limited (subsequently becoming Placer Development Ltd). The target of exploration was cinnabar mineralization that was associated with the carbonate alteration. A total of 10 diamond drill holes were drilled in 1956. Some of the drill core was assayed for mercury, but no assays for gold were made. Most of the drill holes encountered heavily faulted ground. The drill core was transported from the property to Vancouver.
In 1965 the Centennial Showing was covered by the Calex claims. Darbar Exploration Limited trenched and stripped some of the carbonate zones south of the highway, The Sunshine property (093K 046), in 1965, covered the carbonate zones north of the highway, that are were on the Midnight 4 mineral claim in 1982.
The Calex and several other groups, totalling 21 recorded claims, were located on the showings by Messrs. Goodwin, Leggatt, and Vinedge, of Fort St. James, who incorporated a private company, Darbar Explorations Ltd., in June 1965. Bulldozer trenching and stripping was carried out near the Fort St. James-Manson Creek highway.
The Calex 1-4, LAP 2, 3, 4, 9, Hawk 1-5, Frog 1-4, and Wren 1-4 claims were owned in 1969 by L.A. Goodwin, E.D. Vinnedge, and R. Hall. The property was under option to Cominco Ltd. in 1969 who carried out geological mapping, 5,000 square feet of overburden stripping, and test pitting. The stripping was on the Calex 1 claim covered by the Midnight 3 claim in 1982.
In 1982, prospecting and sampling was concentrated upon the Midnight 3 and 4 mineral claims (owned by Murray Morrison) where trenching and stripping over carbonate altered zones by previous workers was extensive. In total, 35 rock samples were collected for geochemical analyses.
In 2000, William Welsh carried out limited prospecting and sampling at the Calex (Prospectors Assistance Program Report 2000-4).
In 2011, Nanton Nickel Corporation completed an exploration program including an airborne helicopter geophysical survey, reconnaissance mapping, prospecting and geochemical sampling over the property containing the occurrence. Four major, magnetic high anomalies were noted on the property. Noted rock sample MRR-23 graded 0.21 per cent nickel in the area immediately surrounding the occurrence (Assessment Report 32715).
In 2012, Nanton Nickel Corporation completed an exploration program including ground mapping, prospecting, soil and rock geochemical sampling and a petrographic study. Rock and soil sampling was not completed on the area immediately surrounding the occurrence.
