Shares in Antofagasta were down on the FTSE 100 in afternoon trading despite the miner reporting a near doubling of its net earnings in the half year ended 30 June.
Group turnover was reported as being up 49.5 per cent from the same period last year to $1.8 billion, while net earnings jumped 91.4 per cent to $451.2 million.
The group said that it would be raising its dividends by 17.6 per cent to 4.0 cents per share.
Copper production in the period increased by 15.9 per cent in the half year to just under 253,000 tonnes.
During the half year period Antofagasta agreed to the acquisition of a 40 per cent stake in the Nokomis copper-nickel-platinum group metal deposit.
Marcelo Awad, Chief Executive Officer of Antofagasta, said, "We had a very strong first half in 2010 with the successful completion of the Los Pelambres expansion bringing increased production, while costs have remained in line with expectations. Combined with the more positive pricing environment, this has resulted in significantly higher earnings compared with the first half of 2009. The Esperanza mine remains on track to commence operations during the fourth quarter of this year, and in 2011, the Group's annual production is expected to exceed 700,000 tonnes which represents an increase of approximately 60% from 2009 levels.
"Demand for commodities has remained strong so far this year and while prices could remain volatile, the medium term outlook remains positive. The Group is therefore well placed to benefit from its disciplined approach to investment and its strong financial position, which has enabled it to continue with its strategy of profitable and low cost growth through the economic cycle. Initiation of a prefeasibility study in the Sierra Gorda district following successful exploration results and the conclusion of the agreement for a stake in the Nokomis project are further significant steps for securing the longer-term potential of the Group for further growth.
"Given the Group's increased production profile, proven ability to deliver major expansion projects, promising exploration prospects and robust balance sheet, together with positive copper market fundamentals, we are well positioned to continue delivering value for our shareholders."
By 13:50 shares in Antofagasta were down 3.80 per cent on the FTSE 100 to 988.00 pence per share.