Conveyor belt didn't cause second Pike River mine blast - police

Twenty-nine men were killed in the Pike River mine blast. Photo / Alan Gibson

A police investigation has found no evidence that the Pike River conveyor belt caused a second explosion in the mine.

The second explosion ended all hope of a rescue attempt.

If there were any survivors from the first blast, all hope of saving them ended then and police called off the rescue.

A clunk sound in a video showing the second explosion led to speculation the mine's conveyor belt may have been turned on, creating a spark.

But police today announced it had concluded its investigation and found no evidence to suggest the conveyor belt was operated or started at any time after the first explosion on November 19, 2010, and no evidence of any causative link to the three subsequent explosions that occurred between November 24 and 28, 2010.

It found no evidence that anyone gained access to a CCTV-monitored hut near the mine portal where the conveyor belt was operated from.

Nor did it find that anyone with the required technical knowledge had accessed computer systems to deactivate audible alarms which would have sounded prior to the belt being started.

The police statement also said that, after consulting with experts, it was concluded there was no evidence there was an explosive atmosphere of gas adjacent to the conveyor belt system or allied electrical circuits.

Police met with the Pike River families today to inform them of the outcome of the inquiry.

The mining disaster claimed the lives of 29 men.

A planned re-entry of the mine this week was put on hold due to elevated oxygen levels at the far end of the drift.

In response to the outcome of the inquiry, Pike River families are calling for anyone with evidence related to the mine disaster to come forward as the investigation into the tragedy gathers steam.

Anna Osborne, a member of the Family Reference Group, said the report had given clarity to some claims that had been made.

Police have been clear that the re-entry of the drift has opened the door for more evidence to come to light and the group urged anyone with evidence to come forward.

"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."

People with information could alternatively contact the group - which represents 28 of the bereaved - families on pikeriverFRG@gmail.com or its standwithpike Facebook page.