TORONTO (miningweekly.com) – North America-focused base metals miner Thompson Creek Metals Company on Tuesday announced that the new Mount Milligan mine, in British Columbia, had started producing copper/gold concentrate, bringing the project that would diversify the company’s portfolio, another critical step closer to commercial status.
The project, which had been subject to delays as a result of worker shortages, winter weather and a 50% budget blowout, was now producing concentrate that would be stored at the site until the company started transporting it to an off-site treatment and refinement facility in the fourth quarter.
Adding copper and gold to the miner’s molybdenum portfolio would reduce the risk of relying on a single commodity.
The NYSE- and TSX-listed company said that since production started earlier this month, the mill had produced about 500 t of saleable concentrate with a specification of about 25% copper and 30 g/t gold.
During the present phased mill start-up, the throughput rate was between 1 500 t/h and 2 000 t/h. The processing plant was currently operating with one of the two ball mills. The second ball mill, along with its primary related flotation circuit and the pebble crusher, were still in the commissioning and start-up phase.
The copper/gold project’s costs spiralled about 50% from the initial estimate of C$915-million. Royalty company Royal Gold is entitled to buy 52.25% of gold produced at Mount Milligan for $435/oz under the terms of a streaming deal that Thompson Creek signed to obtain financing.
The project contains about six-million ounces of gold and about 2.1-billion pounds of copper in reserve.
The operation is expected to reach commercial production in the fourth quarter of this year, producing 60 000 t/d of ore over a 22-year mine life.