Tonnes of concrete poured into 'critically important' Pike River Mine air feed where miners could have gathered - Electrical expert

An expert investigating the Pike River mine disaster has claimed a mine manager pumped tonnes of concrete into a vital air feed, likely where the miners gathered after the first explosion, "completely obliterating" evidence.

Thursday marked the 10th anniversary of the 2010 coal mining accident on the West Coast which claimed the lives of 29 men.

Electrical expert Richard Healey, who spent two years helping the families investigate, appeared on Newshub Nation on Saturday claiming 350 cubic tonnes of concrete was poured into the mine.

"We have the invoices for the material, 105 tonnes shipped from Australia in seven shipping containers. We have eyewitness testimony from people who put material down the shaft, the process took three days. We know that the contract which was signed to do that specified that 350 cubic metres of material would be used."

He said it occurred in 2011, less than a year after the first explosion.

"The manager of the mine, who was the manager at the time of the first explosion, participated in a decision to pour 350 cubic metres of concrete down a shaft and into a fresh air base, completely obliterating all evidence," Healey said.

"So while everyone thought they were gathering concrete evidence, they were, in fact, covering the evidence in concrete."

Healey told host Simon Shepherd that there is "a lot of evidence" some of the miners survived the first explosion on November 19, 2010 and they likely would have gathered at the fresh air base. If they had, their bodies may now be entombed in concrete.

"We think there is a lot of evidence of survivability, for instance, the area where the police filled with concrete contains two self-rescue caches, one of which is open and is apparently empty. 

"Now we think that is pretty good evidence that someone was in there after the first explosion, so evidence of survivors, but we have much other evidence that would suggest that survivability was possible after the 17th."

He also revealed in the past week he had discovered a new pipeline discovery which may allow them to feed a camera into the area behind the rockfall.

"One of the things, which is incredibly frustrating for the families, is that there has been very little credible work done to see what is behind the rockfall. Now we have a god-given gift of a pipeline that goes into precisely that area," he said.

"Unfortunately, the history of Pike River doesn't lead me to believe that anyone will make a coherent effort to use that to insert a camera or robot into that area. It's important to remember... the area we are talking about is less than 50 metres from the back of the rockfall, an area which is critically important to us."

He told Newshub Nation the pipe is 30cm wide for much of its length, and then reduces to 20cm once it gets past the area they are interested in exploring.

"It's a good size pipe. You should remember that in 2017, Andrew Little signed off on a $3 million program to put a borehole down and run a Canadian built robot down a much smaller pipe."

He said the families of victims now hope the Pike River Recovery Agency, Police and Government will use the pipeline to at least establish whether or not the pipeline can be used to get a robot in behind the drift.

"The bottom line is, if there is one thing I think people should take away from this, 10 years has not solved this problem, they have not given us answers. Ten years has simply informed us about the questions we should be asking, and now is the time we should be answering those questions."