Aug 16, 2011 (Dow Jones) -- Zambia's July copper output fell by 18% compared with last July, due to lower-than-expected output at a number of mines in the country, the Central Bank of Zambia said Tuesday.

"Some copper mines experienced lower recoveries during the month of July as a result of low-ore grades," a trade official told Dow Jones Newswires.

Copper output totaled 65,176 metric tons in the month, down from the 79,671 tons produced a year earlier, the bank's data showed. July copper exports also fell, by 12% to 67,507 tons.

July cobalt output fell by 5% to 571 tons compared with 599 tons produced last July.

July copper output brought Zambia's cumulative copper production since the start of the year to 472,891 tons, a 1.2% on-year fall from 478,734 tons.

Zambia is Africa's largest copper miner and the continent's second-largest cobalt producer after Congo.

The Bank of Zambia has forecast 2011 copper output at 900,000 tons, compared with around 820,000 tons in 2010, as a number of miners are expanding operations in the country to take advantage of strong copper prices.