Canadian Mining Journal

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COPPER: Copper North eyes agitated leach for Carmacks ore treatment

YUKON – Ongoing metallurgical tests of mineralized material from the Carmacks copper project point toward agitated leaching as the most economical process for the recovery of copper, gold and silver.



YUKON – Ongoing metallurgical tests of mineralized material from the Carmacks copper project point toward agitated leaching as the most economical process for the recovery of copper, gold and silver.

The Carmacks project, 220 km north of Whitehorse, is wholly owned by Copper North Mining of Vancouver. The company acquired the property in 2011 from Western Copper.

Processing will most likely include three-stage crushing to 80% passing minus 13 mm, followed by rod mill grinding to 1 to 2 mm. The ores are then placed in an agitated tank for leaching of copper oxides with weak sulphuric acid. Testing has indicated 84% recovery of total copper with leach times of 16 to 18 hours; however, the addition of waste heat from the sulphuric acid plant could further reduce the leach times. The leachate is pumped to the solvent extraction electrowinning (SX/EW) plant for recovery of cathode copper.

The solids from copper leaching will be washed and releached in a second set of agitated tanks with lime and cyanide. Gold and silver are recovered from the cyanide leachate by using a Merrill Crowe circuit followed by refining of a doré product.

Copper North says this metallurgical testing will form part of the Carmacks pre-feasibility study to be completed in mid-year.

Learn more about the Carmacks project in the latest corporate presentation at CopperNorthMining.com or by clicking here