Shares in FTSE 100-listed miner Antofagasta slumped today, dragging down the rest of the blue chip index, after the company said its full-year copper output will be "close to the lower end" of its forecast range.
Production rose across the board in the third quarter, with copper production rising 9.4 per cent year-on-year to 504,000 tonnes, while gold production jumped 13.6 per cent to 180,000 tonnes, the company said in a production update today.
But despite "strong productivity growth" over the quarter, this has not been enough to lift its 2016 outlook.
"Performance is expected to continue to improve during the final quarter of the year, with full year 2016 copper production expected to be close to the lower end of the original guidance range of 710,000 to 740,000 tonnes," said chief executive Ivan Arriagada.
Antofagasta previously warned it would be within this range in its half-year results in August. The group has suffered under the copper price rout this year, which reached an apex in January and have continued to trade low since.
Shares in the group, which has operations in Chile, Bolivia and Peru, were down 7.3 per cent to 501p in early afternoon trading. Antofagasta's stock fell around eight per cent on the open.
Read more: Antofagasta posts mixed production update
Arriagada, who has only been at the helm of the mining giant for six months, added:
Since becoming chief executive I have continued to focus our efforts on reducing costs and improving operational efficiencies…We now expect cash costs for the full year to be $1.25/lb, 5c/lb lower than previously guided.
As part of these efficiency programmes we have also reviewed our mine plans and wider operational activities to improve decision making and the accuracy of forecasting.
This has involved a rigorous assessment of our plans with a focus on profitable tonnes and a higher level of certainty without compromising safety or operational standards. Following this review, production in 2017 is expected to be in the range of 685,000 to 720,000 tonnes.