Antofagasta joins other major miners - BHP Billiton,, and Rio Tinto - that have also signalled lower copper output this year.

"The physical copper market continues to look tight and the outlook for next year remains positive despite ongoing fears about disruptions to global trade," Chief Executive Officer Iván Arriagada said in a statement.

The London-listed company said it now expects copper production to be between 705,000 to 725,000 tonnes with strong production expected in the fourth quarter. The company had earlier forecast output at between 705,000 and 740,000 tonnes for the full year.

However, copper production in the third quarter of 188,3000 tonnes was about 4.3 percent higher than last year and 15.4 percent higher than second quarter as a result of higher production in all of its mines.

The copper miner said its net cash costs for third quarter fell about 15.3 percent sequentially to $1.27 per pound, as it cuts costs to fight inflation, and maintained full year cost guidance at $1.35 per pound.

The company now expects capital expenditures for the year to be lower than the $1 billion it previously forecast.

The miner also said it was investigating a contractor's fatal accident that occurred at its Los Pelambres mine in Chile in October.

(Reporting by Shariq Khan in Bengaluru; editing by Patrick Graham, Amrutha Gayathri)