When the plugging work under way at the Pike River Mine is finally completed to make it safe enough to attempt a re-entry, Mines Rescue personnel will first have to haul debris out of the way, including four robots and a loader.
The first step in the $7.8 million re-entry operation began at the weekend as the military started removing gear from the top of the ventilation shaft. The shaft will then be sealed with concrete and another seal put in front of the rockfall - brought down 2.4km inside the mine, as a result of the November 2010 explosions - before the tunnel can be re-ventilated to allow Mines Rescue to walk in.
However, it could take up to six months to reach that stage.
Mines Rescue manager Trevor Watts said today the rescue team would remove the debris and equipment as they came across it.
"We will pull it out as we go.''
That also means the re-entry could take time - everyone stresses there are too many unknowns to know just how long - but Mines Rescue expects to be able to use machinery to pull out the broken-down machinery.
Although no one has been far inside the tunnel since the disaster, the series of four explosions that killed 29 men are expected to have taken their toll with other unseen devastation deep underground.
Known debris inside the mine is expected to include:
* Four robots.
* The loader which survivor Russell Smith was in. He tried to hide low behind its steel door to avoid the force of the blast. It is stuck 1590m inside the tunnel.
* Possibly parts of the conveyor
* Lots of debris between pit bottom and stone, where there was a lot of infrastructure.
Spokesman for some of the families, Bernie Monk, said he believed some of the bodies could be found close to the rockfall.
Police would also be involved in that phase of the operation, due to the investigation, but also in case any bodies were found.
He thinks once the experts get into the tunnel, it will happen fairly quickly, especially as Mines Rescue would not have to work in breathing apparatus once the mine atmosphere has been re-ventilated.
However, both Mr Monk and Mr Watts agreed there was no chance of going through the rockfall due to health and safety concerns.
"They would rather bore around it,'' Mr Monk said.