Police say there's no evidence that the conveyor belt inside Pike River caused the second explosion that ended all hope for the 29 men inside.
An investigation was launched in 2018 after speculation that the conveyor belt had been restarted following the first explosion.
It was believed that this could have created a spark which ignited the methane in the mine, triggering the second blast.
If there were any survivors from the first blast, all hope of saving them ended then and police called off the rescue.
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But on Saturday, police announced the conclusion of their investigation. They said there was no evidence that the belt had been operated or started after the first explosion, and there was no link between the belt and the later explosions.
"Police have found no evidence to suggest that the conveyor belt was operated or started at any time after the first explosion on 19 November 2010, and no evidence of any causative link to the three subsequent explosions that occurred between 24 and 28 November 2010," their release states.
"Police found no evidence after consulting with experts that there was an explosive atmosphere of gas adjacent to the conveyor system or allied electrical circuits, and no evidence that the atmosphere at the grizzly, where the belt ends, was anything other than fresh air."
Official documents from the time show authorities considered turning it on to check if the mine was obstructed - or to give survivors a chance to ride it out.
A risk assessment show police and Pike River management were discussing it as an option, deeming it a "moderate risk".
And footage from inside the mine appeared to show a 'clunk' sound followed by the conveyor belt moving before the mine explodes.
Police say they examined the risk assessment documentation regarding the proposal to start the conveyor belt and say there is "no evidence that this proposal was supported or approved at any stage during the rescue phase, and no evidence that official authority to start the belt was issued by NZ Police or anyone else on 24 November 2010".
The Pike River families say the police report shows that the pursuit of justice is being taken seriously and urge anyone with evidence related to the mine disaster to come forward.
"The police have been clear that the re-entry of the drift has opened the door for more evidence to come to light and we are pleased they are making good on that," says Family Reference Group (FRG) member Anna Osborne.
"We are aware that members of the public may still be holding significant evidence. We urge anyone who has files, names, or any other form of evidence to bring it forward to the police now.
"We have waited nearly nine years for truth and justice, now that chance is here we must make sure we do everything we can to secure it. People who have evidence need to come forward."
Newshub.
