Investors sent OZ Minerals Ltd shares tumbling more than seven per cent after the miner lowered its full-year gold production guidance and posted sharp falls in gold and copper quarterly production.
At 1530 AEST, Oz Minerals shares were 7.54% lower at $4.29, against a slight benchmark fall of 0.15%. Earlier Oz Minerals shares fell as low as $4.255.
In the three months to June 31, OZ Minerals produced 17,379 tonnes of copper concentrate, significantly lower than the 25,521 tonnes produced in the previous corresponding period.
In the same period, the group produced 31,018 ounces of gold, lower than the 34,475 ounces produced in the June 2012 quarter.
OZ Minerals reaffirmed its position that production in the year would be weighted towards the second half.
However, the miner did lower its full-year production guidance for gold production to between 120,000 ounces and 130,000 ounces. At the group's annual general meeting in May, gold production guidance was set at between 130,000 to 150,000 ounces of gold.
"Gold production will depend on the ore blend fed to the mill with preference given to copper ore because of its higher revenue contribution," the group said.
Full-year copper production guidance was maintained at a range between 82,000 tonnes and 88,000 tonnes.