INTERNATIONAL ROBOTS: Top, the Australian robot and bottom, the America robot, both being brought in for the rescue operation at the Pike River Coal mine.
LATEST: Dramatic footage of a massive 52-second-long gas explosion has been shown to families of trapped West Coast coal miners.
Grey District mayor Tony Kokshoorn said the video of the explosion clip had made a significant impact on the families.
"It wasn't nice. There was a huge amount of force coming out of the front of the mine and it went for 52 seconds.
"It was continuous and the frightening thing is, it was probably up to 2.5km from the source. We are talking about what was being blown out of the exterior mine mouth. It's a shame - it was considerable force.
At a press conference currently underway Superintendent Gary Knowles said the likelihood of a rescue was diminishing. "The situation is bleak, it is grave", he said.
The families are extremely frustrated they can't send teams underground.
Kokshoorn said families were also told at a 4.30pm meeting that there was an Air Force Hercules that had landed at Greymouth, but not what was onboard.
"It is obviously something of importance and I found that a bit odd. But they know what they are doing."
Asked if the authorities were still talking rescue, he said: "Yes, but they are starting to temper this.
"This clip [of the explosion] went for 52 seconds and we consider that extremely long for a blast. What they are trying to say is it was a very large blast."
Told that the Prime Minister in the House today had used the word 'recovery' rather than 'rescue', Kokshoorn said: "We are not saying that, we are still talking rescue."
"Until we see fatalities, we do not accept that; or we look for some sort of a miracle.
"Until someone tells us otherwise, we have got to look at it from that angle."
Relatives were shown the footage at council offices during an update from the rescue team this afternoon.
A Government source said the presentation to families went well: "Nobody walked out".
The source said families were also given a further explanation of why rescue teams still can't enter the mine.
The footage is now to be shown to media at a press conference, and will be on Stuff shortly afterwards.
I read earlier rescuers will have to walk 2.5km underground to reach the first intersection of tunnels, and they don't know what they will find there ..
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