Gold-bearing skarn in the Hedley camp is hosted in Upper Triassic Nicola Group rocks and is genetically related to the Early Jurassic Hedley Intrusions, a suite of subalkalic, calcalkaline dioritic intrusions. A series of facies changes recognized within the Nicola succession is related to deposition across a fracture- controlled basin margin; it is economically important as the gold mineralization in the Hedley district is lithologically, stratigraphically and structurally controlled. See Nickel Plate (092HSE038) for detailed regional and property geology.
The Candorado occurrence consists of two mill tailings piles from the historic Nickel Plate mine (092HSE038). The "old" (pile 3) and "new" (pile 4) tailings piles are located within Lot 2900 at the old Nickel Plate mill site along the Similkameen River. Pile 3 contains indicated reserves of 555,145 tonnes grading 1.206 grams per tonne gold, and pile 4 contains indicated reserves of 969,690 tonnes grading 1.522 grams per tonne gold. The tailings also contain lesser quantities of silver. A total of 1,524,835 tonnes of tailings grading 1.405 grams per tonne is available for processing (Assessment Report 15714). Pile 4 has now been mined out; Pile 3 is in the permitting stage for production (Candorado Mines Ltd., 1992, personal communication).
The tailings are comprised of oxidized and leached sulphidic sludge and slime. A potentially feasible means of processing the material appears to be in heap leaching pelletized tailings. Preliminary metallurgical tests of the tailings (cyanide agitation and agglomeration and short column leach tests) were performed (Assessment Report 15714).
In 1988 test production began; approximately 45,355 tonnes of agglomerated material were placed on leach pads (George Cross News Letter #179, 1988). Over 368,282 tonnes of tailings were mined, agglomerated and stacked on the leach pad in 1990. These tailings contain an average of 0.803 gram per tonne gold (George Cross News Letter #225, 1990).
Measured geological (proven) reserves at Candorado are 890,000 tonnes grading 1.37 grams per tonne gold (Open File 1992-1).
Candorado Operating Company Limited operated the Mascot Gold tailings project at a designed rate of 36,000 tonnes per month. The project closed later in the fall of 1995 (Information Circular 1995-9, page 10).