Pike River fire fully out - experts

Aerial photo of smoke coming from the Pike River Coal Mine portal, where up to 25-30 miners trapped underground after an explosion, Greymouth. Photo / NZPA

The fire which has been raging for days at the Pike River Coal mine is out, say Australians brought in to operate the GAG jet unit which has been pumping carbon dioxide into the mine.

"I'm not quite sure of what the police media are releasing at this stage but from our point of view of operating the GAG unit, we're very confident that the fire at the mine is out," said Wayne Hartley, the state manager for the Queensland Mines Rescue Service, which owns and operates the GAG Jet.

But this evening, police released a statement saying reports that the fire was out were "premature".

"Conditions are constantly changing and we are currently validating the information we have," said Superintendent Gary Knowles. "The mine is still very volatile and extremely hot.

"Test results change so quickly and we would need several days of validated results before we could conclude the fire was out."

Even if the fire is out, it does not mean a recovery team can go in any time soon.

Mr Hartley told the workers were now in the process of cooling the shaft - the long entrance way into the mine itself - and that may take some time.

"So the New Zealand mines rescue and, of course, New Zealand fire authorities, have assisted in getting water up to the shaft and they're currently cooling that shaft and that will go on for some time.

"We'll continue to do gas monitoring to confirm the environment of the mine and that we don't have any progressing problems or that anything is escalating or anything like that.

"So what we're trying to do now is validate that information that we have, that is, our indications are the fire is out and that will be done over the next 24 hours, continue to cool, to do the gas monitoring to confirm that.

"In order to progress to the next stage - the next stage would be to seal the mine and then allow it to cool.

"That's any of the coal that may have been on fire in the mine, that will all need to cool down."

Asked how long the cooling process will take, Mr Hartley replied "how long is a piece of string.

"I would think that they would be considering some time, that it may be after Christmas."

Asked, realistically, what the chances were of entering the mine again, he said: "Well, I'm always optimistic and I think there is certainly hope from the community, I think there would be hope from the management of the mine and I think there would be hope from the Government, that they could - we could - re-enter the mine.

"We certainly have the confidence and the optimism that it will be achievable."

Paramount on everyone's minds, however, was not risking injury to anyone going in.

"If we can stabilise this mine and stabilise the environment how we enter the mine will be a course of very intensive planning and risk management.

"Normally, when you stabilise the mine's environment and then you re-enter you virtually claim it back piece by piece and it might be 100 metres at a time or 200 metres at a time.

"That's the way mines' rescues teams are trained to reclaim a mine back and certainly the knowledge and the ability is there - it's whether the mine will allow us to do that."

One of the big worries about going in was that as soon as oxygen got into the mine the coal may start to go through some spontaneous combustion.

"The other condition is we don't know the roof structure or the rib structure of the mine after these events so we don't know what the condition of the mine is.

"So as we re-enter, it's done very cautiously, done with a huge amount of safety.

"We believe that we can re-enter the drift because that's all stone. That's the entrance which is 2.3 kilometres long. That in itself will take some time but we believe we can re-enter the mine and then all those experts would then come together and we would need to gather information to confirm the condition of the mine before we take any further steps."

Reclaiming the mine at 100 metres at a time is around three days work, at least in the beginning stages, he said.

"It's very hard to put a rule on it because what we do is we'll enter the mine and we will ventilate the first section and build a stopping and then we will continue to inert the next section, have the rescue crews go into the next section and build another stopping."

A stopping is a wall which seals that part of the mine off from the rest.

"Then we re-ventilate that, so we bring in ventilation systems to re-ventilate it and turn it back to normal air and take the first stopping down and then put more inert product in to gain the next portion of the mine and we progress a bit further and put another stopping up."

- with NZ Herald staff