London-listed Antofagasta has started repairs to the concentrate pipeline at Los Pelambres, in Chile, with access restrictions partially eased.
The copper miner said on Wednesday that the pipeline should be back in operation by the end of the month.
During the shutdown, the processing plant has been operating at lower rates of throughput, with concentrates being stockpiled at the plant. These would be transferred to the port between July and October using the spare capacity of the pipeline.
Antofagasta said that the full-year copper production would be at the bottom end of the original 660 000 t to 690 000 t guidance range.
A further update on the impact of the leak, first detected at the beginning of June, would be provided in the second-quarter production report on July 20.
The company said total expenditure to repair the pipeline and bring it back to normal operations was not expected to be material.