A report by Sonami, which represents copper miners across Chile, the world's largest producer, said the realities of the coronavirus were forcing companies to weigh tough decisions.

"We have seen miners go from providing information about the disease and taking preventive measures to halting projects already underway," the association said in a statement sent to Reuters. "A decrease in production is already being contemplated in some companies."

Large companies have reduced the workforce at their mines by up to 30% in a bid to cut contagion risks while others, such as state-run giant Codelco [CODEL.UL], the world's largest copper miner, have suspended expansion and improvement projects. 

Sonami said the small and medium-sized companies it represents had been particularly hard-hit since they do not have the financial resources behind them of multinational giants such as BHP, Anglo American, and Antofagasta.

Anglo American told Reuters it would announce any eventual impact on production, but said it "believed that (the impact) would be minimal considering that it could continue processing stock-piled mineral."

Antofagasta said the temporary reduction in its workforce to date had had a "limited" impact on production but that it planned to review its annual output projections in its first quarter report.

Codelco and BHP did not respond to requests for comment.

Sonami said that some medium-sized miners, already hard hit by softening global copper prices, had begun temporarily closing operations.

On Friday the Chilean government reported 3,737 confirmed cases of coronavirus and 22 deaths from COVID-19 to date.

(Reporting by Fabian Cambero, writing by Aislinn Laing; Editing by Chizu Nomiyama and Rosalba O'Brien)

By Fabian Cambero