On Friday after the third explosion, ILN asked coal mining safety academic David Cliff whether each subsequent explosion made it harder to find out what happened with the first one.
“Absolutely,” he said, explaining that each explosion would destroy forensic evidence.
“Of course it’s going to make it more difficult.”
While the third explosion was smaller than the others and Cliff was hopeful that the reasons behind the first blast could still be uncovered, the fourth explosion on Sunday was considered the biggest so far.
The fifth explosion yesterday and subsequent fire underground is adding to concerns that evidence will be destroyed.
The bodies might also be vapourised given the extreme temperatures involved.
The possibility that the cause of the first explosion might remain unknown is another blow to the industry.
There are question marks over the sophistication of the gas monitoring at Pike River, plus over New Zealand’s safety regimes for underground mines, but methane explosions have a variety of possible causes.
The Pike River mining disaster is unique in that it was a hydro-mining operation, and also because of the sheer scale of the explosions for such a comparatively small underground coal mine.
But some aspects of the Pike River mine were not unique.
While it mined a gassy seam, there are gassier seams around the world and particularly in the Illawarra region of New South Wales.
It was here that in-seam drilling was pioneered for gas drainage purposes, which not only improved safety but increased development rates.
Pike River chief executive Peter Whittall started his career and rose up the ranks at Illawarra mines, and was certainly experienced in the perils of mining gassy seams.
Whittall has revealed there was an “unsafe” incident at the time of the first blast, but further details are yet to be disclosed.
But if this incident involved in-seam drilling, there could have been a possibility that Illawarra mines could have learned from the disaster.
If the cause was related to driving roadways, the lessons learned could have been far more encompassing for operations around the world.
It’s also possible that the unforeseen cause was related to hydro-mining, with anything learned likely to be of great assistance to Solid Energy’s Spring Creek mine in the country which also cuts coal using high-pressure water.
There are also fears that Pike’s ventilation system might have failed before the first explosion took place.
The Chilean rescue conundrum
With the miracle Chilean mine rescue still in people’s minds, expectations for more than the two survivors of the first blast were high in New Zealand.
But the situation at Pike River was completely different from the cave-in incident at the Chilean copper-gold mine.
The miners at Pike not only faced a gas explosion and its associated pressure wave, but the consequential loss of oxygen and a fatal surge in carbon monoxide.
Under the operation’s emergency procedures, miners must also make their own way out of the mine using self-contained self-rescuers, and there was no safety refuge chamber.
By Saturday morning the chances of any more survivors were slim, and the 29 missing miners were assumed to be dead after the second explosion last Wednesday.
But with three more explosions rocking the colliery since, Pike might be questioned for not sealing the mine from the surface after the second explosion, which was a clear indication there was still enough heated material and gas to fuel more explosions.
This action could have stabilised the atmosphere underground and offered more protection for the disaster scene and to aid later investigations.
Meanwhile, the mine could be inerted this week with the GAG unit supplied by Queensland Mines Rescue Services, but mine management is considering sealing the mine because of fears the coal is on fire underground.
Cliff is an associate professor at the University of Queensland’s Minerals Industry Safety and Health Centre and is highly experienced in fighting fires in underground coal mines.
