Johnson mine begins commercial output

The Johnson Camp copper mine near Benson, Ariz., has reached commercial production and will be operating at full capacity by mid- October, says owner Arimetco International (TSE). Ore from the mine is fed through a solvent-extraction electrowinning plant which Arimetco built at a capital cost of about US$3.2 million. Mining and milling costs are estimated to be 50 cents per lb. copper.

Mineralization at the Johnson mine is made up of both secondary copper oxides and acid soluble copper sulphides. The copper sulphides amount to about 37% of the total copper.

At full capacity, the mine will produce about 30,000 lb. of high- grade copper per day for a total annual production of about 11 million lb. Arimetco is expecting a mine life of about 12 years.

In Nevada, the company has recently received tentative approval to begin construction of a new heap leach facility at its 100% owned Yerrington copper mine near Reno, Nev. Arimetco says the new pad will quadruple the project’s heap leach area and will boost production by 25,000 lb. per day. Currently, the mine is operating at less than half capacity.