Flames in a ventilation shaft at the Pike River Coal mine have disappeared.
Police say a concrete pad around the shaft has been cooling since the flames disappeared, raising hopes that firefighters will be able to cap the vent.
Poisonous gas levels in the mine are also decreasing in the mine, with some areas registering as inert, they say.
West Coast Superintendent Gary Knowles says extinguishing the flames is "encouraging" progress.
It is a step towards putting out a coal fire that is stopping teams recovering 29 bodies from the mine, he says.
"This is an important step in allowing us to get a metal cap on the vent shaft.
"We will keep running the GAG machine. If we can get the cap on this it will help the GAG in putting out the fire inside the mine."
But he stressed entry to the mine is still a long way off. The Gorniczy Agregat Gasniczy (GAG) machine has now been running for six days.
"Even with all the expertise and resources available to us this is still an operation which will take weeks, if not months."
Chief Coroner Neil MacLean will visit the Pike River mine later today as part of his inquiry into the tragedy.
He is due to meet with families of the dead miners tomorrow.
Mr Knowles says he will give Mr MacLean a full briefing on the recovery operation at the mine.
Pike River chief executive Peter Whittall told Radio New Zealand this morning the blaze had been starved of oxygen and the methane has been displaced in the mine.
The level of carbon monoxide had been reduced from 30,000 to 40,000 parts per million, to "a few 1000 parts per million", he said.
Radio New Zealand reported the GAG cost about $10,000 an hour to run, using 15,000 litres of aviation fuel. There has been not yet been an agreement as to who will pay for the recovery operation.
- with NZ Herald staff
Flames from Pike River mine vent disappear
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