Families of 29 workers who died in the Pike River mine are relieved the mine is being re-entered at long last in an effort to recover the remains of their loved ones.
It is more than seven months since explosions in the West Coast mine left the 29 men dead, and experts are finally confident the gas levels are safe enough to go in today.
Images captured from cameras put inside the mine have suggested there may be bodies still intact inside.
"We are just really happy that finally it's started," said Neville Rockhouse, whose son Ben died in the mine. His other son Daniel got out alive.
"There is a sense of 'at long last'. It's been seven months and it's been rather arduous and very stressful ... and finally things are moving in the right direction."
Bernie Monk, who lost his son Michael, said he felt the re-entry should have begun months ago.
"But anyway, it's getting done now and I'm not going to argue about it. Everyone is now working together."
The re-entry will begin today when a New Zealand Mines Rescue team enter through the sea container and concrete air lock, carry out a reconnaissance about 200m inside, and then select the best place to build a temporary air seal.
Gas monitoring equipment will be set up inside the mine by a second team.
The gases will be drawn out by a ventilation fan. The air lock at the front entrance will then be removed and permanent ventilation doors will be installed.
Rescue workers can then work their way into the mine stage by stage, installing further seals as they go to keep the environment safe.
"Everybody at the mine and involved in the process is very keen to be getting on with it," said statutory mine manager Steve Ellis.
There has been speculation the operation to try to reach the remains could take up to two years.
Mr Ellis conceded it would take months.
But Mr Rockhouse said putting timeframes on the operation was guesswork.
It is still unclear who will pay for the costly operation to recover any remains, with the victims' families and their legal team looking to the Government after receivers took over at the mine and had no body recovery plan.
Prime Minister John Key has not ruled out giving taxpayer money to the venture, but says it would need to be a credible plan.
Mr Monk said the receivers, PricewaterhouseCoopers, want to prepare the mine for sale, and had committed to paying for re-entry until a rockfall 2.4km into the mine.