It could be several days before the body of 59-year-old Craig Butler is able to be recovered from the mine site where he was buried alive.

Key points: The NT Government was made aware of previous safety issues at the mine site

The NT Government was made aware of previous safety issues at the mine site The timeframe for recovering the body is unknown at this stage due to safety issues

The timeframe for recovering the body is unknown at this stage due to safety issues Unions have renewed calls for industrial manslaughter laws to come into effect

Assistant Commissioner Travis Wurst, who is heading up a taskforce investigating the incident, said about 48,000 tonnes of soil fell on the Darwin man after a pit wall collapsed at the Bootu Creek mine on Saturday.

"That was more than 72 hours ago and survivability for that person is very, very limited. It is likely that he has died as a consequence," he said.

The taskforce, combining NT Police, NT WorkSafe and the Department of Primary Industry and Resources (DPIR), converged on the site — 110 kilometres north of Tennant Creek.

Efforts at the mine have been held up by safety issues.

Initial inspections reported water seeping from a pit wall and unstable ground.

Mr Butler was working as a civil supervisor at a construction company in Darwin until earlier this year.

The ABC understands that one of his motivations for going to the mine was that it would give him more time with his family.

Mine site too unstable to begin recovering body

Assistant Commissioner Wurst said unfortunately it would take some time to start excavation work to retrieve the body, as the area was still considered too unstable.

"What that requires is expertise that has been brought in from elsewhere to assist," he said.

"It may be further days before we are actually able to achieve that.

"We need to bring this person home for the family."

Primary Industry and Resources Minister Paul Kirby said he had been made aware of previous incidents. ( Facebook: Straightouttabootu )

Primary Industry and Resources Minister Paul Kirby confirmed that the NT Government had been made aware of previous safety incidents at the site.

"We are aware of previous incidents that have taken place, some of those have been notified to my department. I am aware of that," he said.

"Incidents that have been notified or involved with WorkSafe, and subsequent investigations, I have no understanding of that. WorkSafe sits with a different minister."

Minister denies department failed to act

Mr Kirby refused to comment on the previous investigations but denied that his department had failed to act in time to prevent the tragedy.

"Every issue that comes to us, and comes to my department, is dealt with appropriately," he said.

"The magnitude of this operation is not something that we have seen for a long time in the Northern Territory."

Workers say safety concerns from previous slips, such this one from earlier in 2019, were not acted upon my OM Manganese. ( Supplied )

Following this latest incident, unions have renewed calls for industrial manslaughter laws and for the NT Government to review all mine operations to ensure safety was a priority.

Construction, Forestry, Maritime, Mining and Energy Union (CFMMEU) NT organiser Kane Lowth said he had been contacted by workers who had made allegations of previous wall slips.

"If that's the case we want to know one, what the company's done, and what the NT WorkSafe has done to make that right," he said.

The Bootu Creek mine was placed in administration in January 2016, before resuming operations in early 2017.

About 140 workers lost their jobs when the mine was mothballed, largely due to a drop in ore prices, and only returned to full production in 2018.

Police have said they would provide a report to the coroner.

Wall collapse 'should never have happened'

A former mine safety boss said the wall collapse should have never happened, and that it seemed like a preventable accident.

"People should not be working close to unsupported high walls or any wall that's not supported," said Stuart Bell, former commissioner for mine safety in Queensland.

Collapsed ground at Bootu Creek mine. ( Facebook: Straightouttabootu )

"There should be a zone in front of that wall that people are not allowed to be — if they have to be there, the wall needs to be supported in some way so it won't fall over."

Mr Bell said there was also technology used by many mines with pits to identify if walls were at risk of collapse, or if the ground was cracking.

"There's also radar technology that scans the walls of the pit all the time," he said.

The ABC contacted the mine for comment but was told that all queries should now go to NT Police.