Pike River: International mining experts send report to Government outlining plan to go further, costing $8 million

International mining experts have sent a report to the Government outlining a plan to go further into the Pike River mine where they believe human remains and critical evidence could be found.

An independent advisory group working with the families of the 29 men killed at Pike River in 2010 has just been sent to the Prime Minister, the Pike River Minister, Police, the Department of Labour, and families of the men.

It's estimated to cost up to $8 million and only take 12 weeks to complete.

Tony Forster, New Zealand's former chief mines inspector and the chair of the independent advisory group, says the plan they've come up with is "safe", "technically feasible" and "should have been done years ago".

Since that fateful day 10 years ago, there's been much deliberation, delay, and anger over the Pike River mine.

In February, re-entry teams reached a roof fall comprised of coal in the drift - a significant milestone.

But that's as far as the politicians want to go. The experts, however, say we could and should go further.

"My personal view is this job should have been done years ago. As a mining engineer, I have never understood why so much dithering has been carried out," Forster told Newshub.

The Government chose not to do a study into the possibility of going further - so Forster and his team, working for free, have done it for them.

"People are afraid to give the families an inch, in case they take a mile," Forster said. "Well, why shouldn't they take a mile? Their 29 loved ones are buried in this mine."

There are two roof falls blocking the mine tunnel. The falls are not rocks, as previously thought - but just coal. The plan would be to inject foam resin through holes from the surface to stabilise the two areas.

The main fan, where critical evidence could be found, is just around the corner from the second roof fall.

Mining crews would need to clear the coal from the tunnel. It's estimated both roof falls are 50 metres long.

The advisory group's plan shows steel frames would be inserted every metre along the tunnel to stabilise the roof, allowing access to the area where the main ventilation fan is positioned. It's thought the fan area would hold vital clues as to what happened.  

Pike River: International mining experts send report to Government outlining plan to go further, costing $8 million
Photo credit: Getty Images

Experts say the plan is both safe and relatively straightforward.

"None of the barriers are really technical," coal methane expert Dr David Creedy said. "The barriers are political and financial."

Steel frames would be inserted every metre to stabilise the roof, providing access to the main fan area - believed to be the site of the first explosion. The fan had been sparking prior to the blast.

Investigators for the family now believe a brass plate was removed from the fan in an attempt to fix it.

That could have allowed explosive gases to pass over the fan's unprotected electrics or arching could have happened inside the fan.

"My question would be; 'why wouldn't you want to look at that area? Why wouldn't you want to physically get to that area so you could carry out the necessary forensic testing?'" Forster asked.

Pike River: International mining experts send report to Government outlining plan to go further, costing $8 million
Photo credit: Getty Images

Parts of the fan - a control panel which went missing and a circuit board part were also lost, and a huge bit of the fan's covering were all blown from the area.

"If we don't get to that underground fan, no one involved in the manslaughter of 29 men will ever end up in a court of law," said Dean Dunbar, whose son Joseph was killed in the explosion. "That's my opinion."

According to the families' experts, reaching the fan area could also lead to the discovery of human remains.

"We owe that both to them and to their families - to bring them to the surface just as a casualty on the battlefield is brought back for a decent burial," Dr Creedy said.

In total, $50 million has been spent on the drift recovery but $8 million more could provide the answers and accountability that have eluded everyone for so many years.

Police said their criminal investigation is ongoing and confirmed to Newshub they plan to drill six boreholes at the mine to enable digital scanning and photography inside the mine. This will cost an estimated $3 million and "this cost will be met within the existing police budget".

Forster said he supports the work police are doing but emphasised that drilling boreholes will not allow police to recover any physical evidence. Police agreed they won't be able to take items of interest out of the mine.

Forster was particularly worried drilling a borehole into the fan area could itself cause a roof fall. 

He said this "was possibly the worst place to drill" as it was an area he and others say the vital evidence may exist.