Kazakhstan's largest copper producer, Kazakhmys, on Thursday reported an 8% increase copper production in the first half of the year, but CEO Oleg Novachuk warned that output could be lower in the second-half of the year.

Interim copper cathode production increased to 170 000 t, as the company boosted output by processing previously mined ore, Novachuk said in a statement.

"Given the progress made in reducing stockpiles, output is likely to be lower in the second half, but we remain on track to meet our full year target," he said.

Kazakhmys temporarily suspended production at four high-cost mines in late 2008, when copper demand and prices dropped sharply, as a result of the global economic crisis. These mines produced around three-million tons of ore in during the first half of 2008.

However, the company's interim output benefited from recovery of production at South mine, in the Zhezkazgan complex, and the ramping up at Nurkazgan West, Karaganda region, which together added around 1,26-million tons.

Kazakhmys reported that more efficient management of the continuing operations, including the transfer of some equipment and personnel from the suspended mines, also helped to offset the reduction from the suspended mines. As a consequence, ore output in first half of 2009 declined by just 1,5-million tons, or 8%, compared to the first quarter of 2008.

The miner increased its ore output by 6% between the first and second quarters of the year, from 7,76-million tons to 8,25-million tons, with modest increases across all four regions.

The Karaganda region saw the most significant increase with the ramping up of Nurkazgan West underground mine, which began production in February.

Meanwhile, Kazakhmys said that gold production had also increased by 8% in the first six months of the year, when compared with the first half of 2008 to 679 000 oz of gold.

Gold metal in mined ore reduced during the first quarter following the temporary suspension of production at Abyz, Kosmurun and Akbastau mines. However, this did not affect half-year gold production, owing to a reduction of work in progress, particularly the processing of stockpiled gold rich Abyz ore.

First-half silver production increased by 10% to 9,14-million ounces.

Production of silver from own material increased by 10% in the first quarter and was 6% higher in the second quarter. There was a reduction in silver metal in mined ore, but this was significantly offset by lower levels of work in progress.

Zinc in concentrate output increased by 15% to 76 000 t, despite a decrease in zinc metal mined with the planned suspension of output at the Akbastau and Abyz mines.

It reported that zinc in concentrate production benefitted from the timing of receipts of material from third-party processors, the processing of stockpiled ore and improved recovery rates at concentrators. However, these benefits were mainly seen in the first quarter, as zinc concentrate production during the second quarter was 8% below figures reported in the first quarter, due to a decline in grades in the East Region, which led to lower zinc metal in ore.