Mine experts offer $8m plan

An $8 million plan to get more evidence from the Pike River mine has been presented to the Government.

A group representing 23 families previously asked the Government to fully assess the risks and costs of recovering the main ventilation fan, considered a vital piece of evidence that may reveal the cause of the explosion that killed 29 men in 2010.

When the Government refused to spend any more money on the mine, the families asked a group of mining experts from around the world to develop a feasibility study for the project.

The Pike River Independent Technical Advisory Group, led by former chief mines inspector Tony Forster, presented the study to the Government yesterday. It said the recovery would cost $8m and take 12 weeks using standard mining techniques.

The Pike River Recovery Agency was tasked by the Government to complete a $50m re-entry of the mine’s access tunnel, or drift, which it achieved in February. It planned to hand the mine site over to the Department of Conservation in June.

Minister Responsible for Pike River Recovery Andrew Little previously said it was a ‘‘technically phenomenal’’ task to go past the roof fall at the end of the 2.3kilometre access tunnel because it was ‘‘inherently unstable’’.

The advisory group’s plan said the drift recovery team brought back new information that the roof fall was mainly coal rather than an extensive failure of the roof strata.

The furthest point the team reached was only a few metres from the junction to the main fan roadway. It said having the main fan underground was unusual in coal mining and there were multiple reports of problems with the fan in the weeks leading up to the explosion.

The group’s plan involved ‘‘conventional, well-proven mining techniques for excavating, supporting and stabilising the roof falls’’ by injecting a concrete-like foam into the void and supporting the roof with a new steel tunnel. It would be undertaken in fresh air using the agency’s existing ventilation system.

Little said he had not seen the plan yet, but the Government’s position had not changed as safety was a non-negotiable bottom line.