The tragedy at the Pike River Coal mine would not have happened if New Zealand had maintained a mining inspector programme canned more than a decade ago, a mining expert says.
A chief inspector would have noticed the dangerous levels of gases pooling at the West Coast mine, and the 29 men who died in explosions from November 19 on would still be alive, New Zealand mine safety advisor Dave Feickert told NZPA.
Safety officials do monitor mines around the country, but the system was inferior to the inspector system that was used until the late 1990s, he said.
The chief inspector led efforts to save men at the explosion at the Huntly West mine in 1992. He succeeded, but the mine was destroyed.
"But nobody was injured. That was the last major explosion where that system was in operation, and it wasn't in operation at Pike River because it doesn't exist."
The critical aspect of the system was that inspectors would have been continually at the mine site and would see a dangerous situation developing.
"The mine was having a whole lot of gas problems...and what would have happened is the mine management would have called in the chief inspectors or specialist inspectors to give them advice on how to deal with the situation as it was developing.
"This wasn't just a one off, it was part of a whole pattern of gas problems they were having. We don't know exactly how the gas explosion occurred because nobody's been able to go in to have a look.
"But we do know enough about what had been going on in the months beforehand to know this was a distinct possibility."
Cutting the inspector programme in the late 1990s meant Pike River management were left isolated and not supported by specialist inspectors with experience in gas management, Mr Feickert said.
However, he stopped short of saying the safety procedures in the mine were ineffective.
"I'm not saying they were totally irresponsible. I'm saying they were very unsupported."
Mr Feickert is working with the Chinese government and companies on a mining safety programme.
"They have a lot more serious problems than we have in New Zealand, and I have to say they have a more effective inspectorate than we have at the moment. That's a bit of a sad comment really because they've gone forward and we've gone backwards."
An inspector at Pike River would have asked about draining the gas buildups before allowing men into the mine, then pushed for installing a proper drainage system, he said.
"A chief inspector and his inspectors would have said 'Look guys, get that sorted out otherwise there will be problems'."
It was not right that Prime Minister John Key was making decisions about mine safety because he was not an expert in the area, Mr Feickert said.
"No wonder the families of the 29 dead are furious. So they should be."
Mr Feickert was incorrect, a spokesman for the prime minister said. Mr Key did not make decisions about mine safety, agencies such as the police did, and the prime minister supported them in their decisions.