Chile-based miner Antofagasta said copper production jumped 9.4 per cent compared with the previous year while gold production dropped.
In its first quarter production report for 2017, the miner said copper output rose to 171,900 tonnes due to higher production at its Centinela mine and its Antucoya mine operating at full capacity.
Copper fell by 16.4 per cent compared with the previous quarter due to lower than expected grades.
Gold production fell six per cent to 53,300 ounces compared with the previous year, or a whopping 41.5 per cent lower than the previous quarter due to lower grades at Centinela.
Chief executive Ivan Arriagada said: "We reassert our guidance for the year of 685,000 to 720,000 tonnes of copper at a cash cost before by-product credits of $1.55 per pound and a net cash cost of $1.30 per pound."
Analysts at Berenberg said the results were slightly below their expectations and tracking at the bottom end of the 2017 annual guidance.
Yesterday, Goldman Sachs downgraded Antofagasta and a number of other miners to a sell rating due a poor outlook for certain commodities, including near-term risks to the price of copper, causing its shares to dip.