The Federation of Copper Workers (FTC) said in a statement there had been “alarming” numbers of coronavirus infections at several of the country’s mines. Measures to tame the spread of the virus had been insufficient, the federation said.

“If it is necessary to halt work in those areas … until sanitary conditions are adequate to protect mine workers, we are ready to do so,” the federation said in the statement.

FTC President Patricio Elgueta said the group had received “a series of complaints” from union leaders at Codelco’s sprawling Chuquicamata copper mine in northern Chile, alleging the miner had failed to protect worker health.

Codelco did not immediately respond to requests for comment.

The FTC reported a mine worker at Chuquicamata died last week from covid-19, the respiratory disease caused by the novel coronavirus. Shortly afterward, Chile’s mining minister, Baldo Prokurica, called on the company “to adopt all necessary measures to protect the life and health of workers.”

Chile is in the throes of the coronavirus outbreak, with new cases cresting at 5,000 a day and deaths from the disease surpassing 2,000. But output from the country’s mines has gone largely unscathed.

Codelco told Reuters in May its production and sales remained in line with projections, even as it had been forced to suspend construction on some projects and third-party contract work since the virus hit Chile in March.