The re-entry – at 11.45 am today – is an emotional time for the lost miners’ families, who called for a rescue and then retrieval mission months ago.

High concentrations of carbon monoxide made it unsafe to re-enter until now, when a seal around the metal container which has acted as a portal into the mine was removed.

It may take many more months before the actual remains of the miners are found, if at all.

Three teams took it in turns to work in the mine today, with safety the paramount concern.

At about 100 metres in, mines rescue staff installed a monitoring point to monitor the mine gases remotely and build a temporary seal, a spokesperson for receiver PricewaterhouseCoopers said.

“The re-entry work is a continuation of the mine stabilisation work, which has been ongoing since the mine was handed to the receivers in January 2011,” the spokesperson said.

“It’s the start of what will be a long process to reach the bodies of the 29 men.

“It will be completed in stages.”

The work in the mine will continue this week and is expected to proceed unhindered by adverse weather.

The next phase of the re-entry process will be the construction of airtight seals along the entry tunnel to the mine.

Mine stabilisation work has been underway since January. Carbon monoxide levels plunged earlier this month, sparking hopes recovery crews could gain approval to re-enter the mine.

PwC then met with representatives of the company and rescue teams to assess a suitable re-entry timetable and plans to finalise stabilisation work at the mine.

The mine’s CO levels have fallen from about 6000 parts per million to below 1350ppm, bringing it close to the safe level of 1200ppm.

PwC’s John Fisk said oxygen levels in the mine were also rising and any decision to re-enter the mine would need to be approved by an expert panel, which included the Department of Labour and Mines Rescue.

Last month PwC reported gas levels, “mainly carbon monoxide”, had risen to such an extent that the mine was unstable.

Sealing work around the ventilation shaft has since been completed.