by Going further into the Pike River coal mine is too hard and too expensive, Minister Responsible for Pike River Reentry Andrew Little says.
The ministers comments come even though no detailed technical assessment or cost analysis has been done.
Little said the Government was not willing to consider doing a risk assessment and cost analysis of recovering evidence from the mines main ventilation fan, which could hold clues about what caused the first explosion in the mine where 29 men were killed in 2010.
He said the mines geotechnical strata was inherently unstable and the technical challenge of getting past a roof fall blocking the mine workings would be phenomenal.
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He was responding to comments by New Zealand’s former chief mines inspector, Tony Forster, backing calls for the Government to consider examining the fan to try to confirm what happened and bring those responsible to account.
The fan was blocked by a roof fall, which Forster said was only 15 metres long, made of coal and could be removed using standard mining techniques.
The Pike River Recovery Agency reaching the roof fall 2.3km up the drift access tunnel.
The Pike River Recovery Agency’s mission was to complete a $50 million re-entry of the mines 2.3-kilometre access tunnel, which it achieved last month.
Some Pike River families have added their support to calls from fathers Bernie Monk and Dean Dunbar to go 30m further to the fan.
Little said the Government could not give an unlimited amount of money to the project.
As difficult as it is to say and accept, these families have been advised from the outset that this project does not have an unlimited budget. It has already been topped up twice to ensure we fulfil the agreed mandate.
Family members had been told it would cost between $60m to $100m to recover the mine workings, and widow Anna Osborne said that figure was too much to ask the Government for.
Former chief mines inspector Tony Forster says recovering more evidence in Pike River is feasible. (File photo)
However, agency chief executive Dave Gawn told Stuff that figure did not come from any detailed planning.
The agency did some very early, informal and internal, speculative, rough order of cost planning two years ago in order to estimate what it would cost to recover all of the mine workings and whilst $60m to $100m had been projected, it is very speculative, he said.
Agency chief operating officer Dinghy Pattinson previously said it was technically possible to get past the roof fall from a mining perspective, but cost and funding would be obstacles.
Little said technical engineering advice was provided to the agency by a range of experts from New Zealand and overseas.
When asked to provide evidence of the area’s instability and the technical difficulty of recovering the fan, he said the families were aware of the technical challenges and the state of the mine.
A map of the Pike River mine showing the extent of the roof fall in red and proximity to main fan.
Little said seeing how big the roof fall was, and what material it contained, would make no difference to how stable the mines roof was.
A roof fall is a roof fall it doesnt matter whether youve seen it with your own eyes, or its been recorded. The fact is, part of the drift has collapsed because the geotechnical strata is inherently unstable.
He said the agencys mandate was to recover the drift, so it could access an area called Pit bottom in stone, which could contain important electrical information.
The focus now is the forensic investigation to gather evidence, better evidence, to have a better chance of mounting a prosecution to hold someone to account for the deaths of these 29 men.
Forster said geotechnical reports and samples taken from a borehole directly above the centre of the roof fall showed it was supported by a stable 70-metre thick slab of island sandstone.
He acknowledged the coal collapse was unstable, but said he believed it could be supported by arch supports and cement a job that was not particularly difficult nor costly.
