Harry Winston Diamond Corp said recovery at the Diavik mine in Canada's Northwest Territories was slightly less than its expectations in 2011.
The mine recovered 6.7 million carats of diamonds in 2011, compared with the company's forecast of 6.9 million carats due in part to lower-than-expected amounts of reprocessed ore, the diamond miner and retailer said in a statement.
In 2012, the Diavik mine is expected to produce 8.3 million carats.
Harry Winston also said its joint venture partner Rio Tinto Plc is reviewing a new mine life plan for the Diavik diamond mine.
The Diavik mine is operated by Diavik Diamond Mines, a unit of Rio Tinto of London. Harry Winston Diamond Ltd Partnership, owned by Harry Winston Diamond Corp, owns a 40 percent stake in the mine.