Sixty-five miles east of the sun-drenched city of Tucson, Arizona, lies the historic copper mine, Johnson Camp. Active on and off since the 1970s, the mine is being resurrected in response to a booming copper market. As material is extracted at the mine, it will be separated into different piles; oxide copper in one pile and primary sulphide copper in another. The former will be sent to one portion of the heap leach pad for conventional oxide leaching using hydrometallurgy. The sulphides will leach using novel technology developed over three decades by Rio Tinto. Johnson Camp, now operated by Gunnison, will be the ... (full story)