Management at Tasmania's Mt Lyell copper mine say they are unable to confirm if two workers killed in a 30-metre fall were wearing safety harnesses.
Operator Copper Mines of Tasmania (CMT) says police have instructed them to not discuss the specifics of the accident, which resulted in the deaths of 45-year-old Craig Gleeson and 25-year-old Alistair Michael Lucas.
"We do use those (harnesses)," CMT general manager Scot Clyde told reporters in Queenstown.
"I really can't comment on the circumstances of it as yet."
Police had already signalled the question of whether harnesses were worn would be central to the investigation.
Workplace Standards officers remained at the site attempting to piece together what happened 600 metres beneath the surface as the two men carried out maintenance on Monday morning.
Mining operations remained suspended indefinitely.
Mr Clyde defended the industry's safety record, saying it had been a major priority in recent years.
"They're difficult questions to answer in terms of what you mean by safety," he said.
"Like the rest of the industry within Tasmania and Australia, there's been a huge focus certainly over the last 10 years in terms of improving safety by way of systems of culture and engaging people in that."
The Australian Manufacturing Workers' Union has said safety at the mine was not previously a major concern.
Mr Gleeson had been employed at the mine since 1999 and Mr Lucas since 2011.
Both had young families and relatives also employed at the mine.
Mr Clyde said he had known both personally.
"They were good workers, nicely natured, part of a very closely-knit team," he said.
"The guys worked in really well together, socialised together, played sports together.
"It's a fairly small site ... we tend to get to know people pretty well."
Employees were being encouraged to attend the site for counselling or take time off work if they needed it.
Mr Clyde said he had spoken to the families of both men.
"Devastated probably just doesn't begin to describe it," he said.
