Mount Milligan mine, situated approximately 93 kilometres north of Fort St. James, will soon increase its process capacity by 2,500 tonnes of ore per day — to a daily throughput of more than 62,500 tonnes.
Commission of major equipment and components of the new circuit began in October, announced mine owner Thompson Creek Metals Company on Oct. 18.
As the mine continues to perform routine tests and commission all equipment, construction of its permanent secondary crushing circuit is expected to finish this fall.
“We are pleased to have commenced commissioning of the Mount Milligan permanent secondary crushing circuit and look forward to our first feed later this fall,” said Thompson Creek’s CEO and president Jacques Perron in a statement. “Total capital expenditures for the project are expected to be $50 - $55 million, which would be approximately $10 million below guidance.”
At the mine, copper and gold concentrates are produced through a water recycling technique, where the metals are separated from the mined ore by being floated towards the surface.
An expansion of the flotation circuit, with the addition of regrind capacity, is expected to improve gold and copper recoveries, according to the company. A new geometallurgical model is expected to allow operators to better manage the material to the mill, resulting in more efficient mill operations and better predictability.
Mount Milligan mine, along with all other Thompson Creek assets, was acquired by Toronto-based gold mining company Centerra Gold Inc. as of Oct. 20.
The arrangement includes changing Royal Gold, Inc’s streaming interest at the mine from 52.25 per cent gold stream to 35 per cent gold and 18.75 per cent copper.
“Because Centerra is primarily a gold mining company, all of our investors tend to look at us as a gold entity,” said John Pearson, Centerra’s vice president of investor relations. “So we thought that it would be good to maximize the gold exposure from Mount Milligan mine and repositions it as a world-class gold mine.”
Running 24 hours a day, Mount Milligan has been in its production phase since September of 2013 and has a mine-life of 22 years, with 2.2 billion pounds of copper and 5.7 million ounces of gold in proven and probable reserves.
Endako Mine, a molybdenum operation located west of Fraser Lake and previously owned by Thompson Creek, remains under care and maintenance until the molybdenum price is “much higher.”
“We retained the whole molly business as a separate business unit, with the Langeloth metallurgical facility in Pennsylvania generating cash profits that pay for care and maintenance in Endako,” Pearson said. “Right now it’s a cash-neutral business, and we’re just going to hang on to it and wait for a better time in the price cycle.”
In addition to Mount Milligan, Centerra’s assets include the Kumtor Mine in the Kyrgyz Republic in Central Asia and the Boroo Mine in Mongolia. Outside of Asia, the Canadian company also owns the Oksut Gold project in Turkey and is a joint venture partner in the Trans-Canada Project in the Geraldton-Beardmore Greenstone belt of Ontario.
“The acquisition will establish an operating base in Canada — one of the lowest risk mining jurisdictions in the world —which will complement our Canadian-based Greenstone project and provide for further flexibility to expand into the Americas,” said Centerra’s CEO Scott Perry in a statement.