The Tacheeda Lakes limestone prospect lies within a belt of lower Cambrian limestone and dolomite with minor quartzite and slate. The belt trends northwest for 41 kilometres and varies up to 5 kilometres in width.
Regionally, the area is underlain by a series of northwest-trending sediments including limestone, marble and calcareous sedimentary rocks of the Cambrian to Ordovician Kechika Group.
Limestone is exposed in an old rock quarry adjacent to the BC Railway line, just northeast of the isthmus separating the Tacheeda Lakes. Smaller exposures occur in a roadcut 130 metres northwest of the quarry. The limestone is estimated to be at or near surface in an 80- to 100-metre-wide area extending for 280 metres northwest of the quarry. Indistinct bedding at the quarry strikes 110 degrees and dips 50 degrees south; in a roadcut to the northwest it strikes 155 degrees and dips 45 degrees east.
The limestone is dark grey to black and very fine grained. The rock is cut by veins of creamy white calcite up to 0.5 metres wide. Nine chip samples taken perpendicular to the strike over widths of 5 metres averaged 94.1 per cent calcium carbonate (G. Klein, 1983, p. 6). The calcite veins were excluded from sampling because of their erratic nature. Probable (indicated) and possible (inferred) reserves are each estimated at 750 000 tonnes for a total of 1.5 million tonnes (G. Klein, 1983, p. 7).
Work History
B.C. Railway Co. initially quarried some of the limestone for railway ballast. Diamond Limestone Ltd. proposed developing the deposit to supply agricultural limestone. The deposit was mapped and sampled in 1983.
In 1986, Cominco Ltd. completed a program of geological mapping and geochemical (rock and silt) sampling on the area immediately south of the occurrence as the Tach 1 claim. This work centred on the exploration of possible carbonatite or kimberlite occurrences.
In 2011, International Montoro Resources Inc. completed a 1066.8-line-kilometre airborne magnetic and electromagnetic survey on the area as the Tacheeda property. This work was related to rare earth elements exploration.
