Pike River is a name now synonymous with death. While the West Coast coal mine promised much, its explosive end killed 29 men and delivered very little coal.
Ahead of Solid Energy's decision this month on re-entry to the mine's main tunnel, Radio New Zealand chief reporter Gay Cavill considers what is proposed and the hurdles that remain.
Pike River Coal Limited was the new kid on the block.
In 2007, its total development costs were put at $207 million.
At its 2008 annual general meeting, the company was still talking the mine up. It was touted as a "special mine", with "the largest and most valuable hard coking coal deposit in the country" and "the lowest ash content in the world".
A peak workforce of about 150 people was contemplated for a seven-day, three-shift operation.
The plan was to deliver one million tonnes of low-ash, high-grade coking coal each year for 18 years to be used in the Chinese and Indian steel industries.
But the quality of the coal was lower than promised, far less coal than planned had been extracted by mid-2010, and coal prices were dropping.
At 3.45pm on 20 November 2010, Pike River Coal Mine exploded.
Watch the first explosion video, as supplied by police in November 2010
Re-entering the drift
Since the series of explosions ended on 24 November 2010, the furthest anyone has gone into the mine's drift (main tunnel) is 300 metres. A temporary seal has been put in at the 170 metre mark.
Three robots have been sent in, however, with one reaching as far as 1.5 kilometres up the tunnel.
A detailed plan for re-entering the drift has been prepared and has the approval of WorkSafe New Zealand and the Mines Rescue Service. The families of the men also believe it is a safe and viable plan.
According to Solid Energy, Stage 1 has been completed. Stage 2 has been completed to the point of being ready to place a temporary expanding foam (ROCSIL) plug in the drift. All the surface gear is in place for nitrogen injection and ventilating the drift.
Waiting for sign-off
One hurdle now remains before the plan can proceed and before any mine rescue staff can walk up the drift - and it is a major one.
The Solid Energy board has to sign off on heading back in, and it has serious safety concerns about the decision.
When Solid Energy bought the mine in July 2012, it agreed it would take all reasonable steps to recover the bodies as long as that can be "achieved safely, is technically feasible and is financially credible".
Solid Energy has said the atmosphere inside the drift is about 98 percent methane, which is explosive when present in a range from 5 to 15 percent of normal atmosphere.
Last month, Solid Energy CEO Dan Clifford said the company's legal advice was that there needed to be a second mine exit for a recovery to be done safely. He also said that the lack of one at Pike meant a re-entry attempt was now unlikely.
The next Solid Energy board meeting is set for 29 October but the company has said there could be a special meeting just to discuss the drift re-entry. It has said a decision on the re-entry will be made this month.
The families of the men have called for a delay to that decision while their experts study the documents on which the decision will be based.
Solid Energy has said it has not received a formal request to that effect.
Daniel Rockhouse's account
Why is the re-entry of the drift so important to the families, when most evidence suggests the 29 men were behind a large rockfall in the mine's main workings?
Daniel Rockhouse drew a plan of the mine from his hospital bed. He and electrician Russell Smith were the only two survivors among the men who had been underground.
His plan, presented to the Royal Commission into the Pike River Mine Tragedy, shows the last known positions of the men working underground.
The royal commission also heard evidence from Mattheus Strydom, who headed 1500 metres up the drift soon after the first explosion. He saw the light of a Juggernaut (mine vehicle). Nearby, he said, was a man lying on his back, arms outspread.
More evidence was given that three men - Conrad Adams, Riki Keane and John Hale - were in or near Spaghetti Junction, getting ready to come out of the mine on a drift runner. Some of the families believe the drift runner may be in the tunnel with the men's bodies on board.
The families believe it is crucial that re-entry of the tunnel goes ahead to look for any remains and to gather forensic evidence from inside the tunnel.
Re-entering the main mine workings
In July 2012, the Government, Solid Energy and Pike River Mine signed a deed covering body recovery.
Under the deed, Solid Energy is obliged to take all reasonable steps to recover the remains of the men from the main workings in the mine.
But the deed also includes an acknowledgement that if commercial mining does not go ahead, it is highly unlikely the men's remains will be recovered.
Solid Energy has not decided whether it will re-open Pike River as a commercial mining operation, and that decision could be many years away. After all, world coal prices are still low and it has a mining permit which does not expire until September 2037.
It bought the mine before the price of coking coal fell dramatically and before the financial issues it now has to deal with surfaced.
On top of falling coal prices, the royal commission has said an expensive exploration and geological assessment is needed before a return to commercial mining.
The rugged Paparoa Ranges, difficult access and the fact that the western edge of the mine permit area is a national park boundary are additional factors to be considered.
Mine workings - a step too far?
Getting back into the tunnel is proving difficult enough but getting into the main workings may be a step no-one is prepared to take, even to return loved ones to their families, if there are remains to return.
The first physical obstacle to re-entering the main mine workings is a huge rockfall which blocks the entrance to the area where the men's bodies are most likely to be found.
There is no way to know how stable the area is and whether there is the risk of further rocks falling if the debris is cleared away. There is also the risk of explosion and fire.
The drift is the only way in and out of the mine, and the only way to get to the rockfall and main mine workings beyond that.
If it is not considered safe to allow people to go up the drift, the bodies will lie forever where they fell and the mine is likely to be permanently sealed.