The Prime Minister has poured cold water on any suggestion leaked footage from the Pike River Mine shows men deep inside the mine's drift, or that it was keep secret from families.
The footage shows a robot and two mine safety workers inside the Pike River Mine, about three months after the deadly 2010 disaster. Photo: Supplied
The footage, initially released by Newshub and also obtained by RNZ, shows a robot and two mine safety workers - who were wearing breathing gear - investigating inside the drift.
It was taken about three months after the November 2010 explosions in which 29 men were killed.
Family members of the victims, whose remains have been trapped in the mine since the disaster, said the leaked footage proved what they have always known - that re-entry was possible.
They also expressed dismay they had not been shown the footage until a few months ago.
That was rejected by Prime Minister Bill English, who said the families were shown excerpts of the "estimated 20 to 30 hours of footage" from the robot, during meetings in Christchurch and Greymouth in July 2011.
He said after those meetings all of the footage was passed on to the Pike River Royal Commission.
"The showing was to ensure the families were not caught off guard when the information was provided to the inquiry."
Mr English said police told him about 30 family members and supporters were at each meeting.
But they could not tell him exactly which family members attended, and which excerpts of the video were shown.
It was up to the police, the prime minister said, to explain the contradiction between the information they gave him today, and a statement issued last night stating the footage was not passed on "as it was assessed as having no evidential value".
In a subsequent statement, the police said the first statement "was based on a misunderstanding that the aired footage originated from the WA robot on 25 November 2010, not the one sent in on March 15 2011".
Deputy Police Commissioner Mike Clement said police had not sought to withhold anything they believed would be of interest to the families. The majority of the footage involved many hours of featureless tunnels, bore holes or indistinct imagery, he said.
Mine safety workers 'no further than two metres into the mine'
Mr English said any suggestion the two workers in the video footage were "deep inside the mine" or that they were in a "methane-rich environment and that the smoking or steaming robot countered expert assertions the mine was unsafe to enter" was also incorrect.
He said the Mines Rescue Trust has publicly stated the men were working in a container installed at the entrance of the mine.
"Where they were preparing the robot for its journey, the workers - they say - went no further than two metres into the mine during that operation.
"At the time the drift was inert because it had been pumped full of nitrogen."
A former mines rescue team member, Harold Gibbens, told Checkpoint with John Campbell the mine was structurally sound and the gas inside it now was also inert, because it was almost pure methane.
"The amount of gas that Pike River is currently holding, and the seals are obviously doing a very thorough job, it has completely enriched the atmosphere full of methane."
Mr Gibbens said, as long as oxygen was not introduced to the atmosphere, it would be safe to work in there.
Video 'irrelevant' to current risks - Solid Energy
Solid Energy, which has consistently said it is too dangerous to re-enter the mine, also rejected any suggestion the footage showed manned re-entry could be done safely.
Its chief executive, Tony King, said the workers in the footage were in the first few metres of the drift, which was very different to the risks associated with going deep into the mine's shaft.
He said the drift was filled with nitrogen at the time the video was made.
The fact there was no fire when the robot malfunctioned was "irrelevant to the risks associated with the drift now being filled with methane", he said.
There was nothing in the footage that contradicted the company's ultimate decision that manned re-entry of the mine was unsafe, Mr King said.
It was working with government agencies and the families on potential unmanned re-entry options.