The Caledonia occurrence is located on the east side of Rossiter Creek, 250 metres from its confluence with the Kaslo River, and 23.5 kilometres northwest of Kaslo, British Columbia. It has been a significant past producer in this area with intermittent recorded production totalling 10,013 tonnes mined, spanning 1914 to 1967. Recovery totalled 1,854,827 grams silver, 1990 grams gold, 1702 kilograms cadmium, 409,697 grams lead and 473,968 grams zinc. The reader should be aware that production figures listed in BC METAL MM00688 included production from the nearby Monte Christo (082KSW147) but have been separated here.
Silver-lead-zinc mineralization occurs in the Triassic Slocan Group, locally consisting primarily of black fissile phyllites with interbedded limestone, calcareous phyllites and brown gritty quartzites. The general structural trend is 310 degrees, dipping generally southwesterly. Greenstones and ultramafic rocks of the Permian Kaslo Group unconformably underlie the Slocan Group to the east, also hosting silver-lead-zinc mineralization. Satellite stocks, dikes and sills are generally correlative with the Nelson batholith to the immediate south. Late stage lamprophyre dikes are also common.
The Caledonia occurrence is composed of a mineralized fault- fissure zone striking 095 degrees and dipping 75 degrees south. It cuts across laminated, slaty rocks and three or more beds of limestone varying from 1 to 5 metres in thickness, of the Slocan Group. The limestone bed is exposed at the surface and has been traced northwesterly for several tens of metres, in which it is intersected by a number of small crossfractures striking a few degrees north of east and carrying little sulphide mineralization. Minor gold-bearing arsenopyrite was also noted in a few places.
The ore has resulted mainly from replacement of the limestone, but also in fractures in slate, cutting the limestone beds at almost right angles. Significant mineralization is composed of lenses of galena or galena-sphalerite-pyrite in a gangue of vein calcite and siderite with locally some quartz. Faulting along the hangingwall of the vein has abruptly terminated mineralization in limestone. The intersection of the vein with the widest limestone bed was the locus of an early mined orebody.
