A last-ditch bid to allow Mines Rescue to explore the Pike River Mine drift before it is sealed permanently has been abandoned, after families were told that gas levels were still extreme and that protesters would be arrested for impeding Solid Energy.

Some family members and supporters occupied the entrance road to the mine site, at Atarau, from Saturday through to Monday morning, when the quake caused a re-think.

They were pleading for one last look deep inside the drift - the tunnel leading into the mine - for the possibility of finding bodies of some of the 29 men who perished in the November 19, 2010 explosion.

Last night, Environment Minister Nick Smith met with the mine families in Greymouth.

"I have confirmed to the families that Solid Energy has completed the first phase of work for the permanent seal 30m into the drift. Solid Energy has a legal obligation to comply with an improvement notice issued by the High Hazards Unit of Work Safe New Zealand to complete a 'type C' seal by the end of November," Smith said in a statement issued late last night.

About a week of work was required to finish the seal.

Smith said there was no new information that had changed Solid Energy's view that safe re-entry was not possible.

Monitored methane levels in the drift beyond the new seal had been rapidly increasing and were approaching the levels in the remainder of the drift of 95 per cent.

"The mine is full of methane and is likely to have residual heat sources capable of triggering an explosion if there was a source of oxygen. There is the added risk of rockfalls," he said.

The mine had only one exit and that remained a fundamental flaw for the safety of any re-entry attempt.

Flames burn from a ventilation shaft above the Pike River mine. Photo / Supplied
Flames burn from a ventilation shaft above the Pike River mine. Photo / Supplied

"The Government has spent more than $5 million trying to find a safe way of re-entering the mine and we support the conclusion that it is not practically possible," Smith said.

In their statement today, Anna Osborne and Sonya Rockhouse said the meeting was "very heated".


"We have sadly come to the decision that we will stop our occupation at the Pike River gates due to us being told that if we impede Solid Energy's efforts to get through the gates to seal the mine we will be arrested," they said.

They thanked their supporters and said they were "eternally grateful".

"We are both incredibly heartbroken but Anna has a huge battle to fight with her health and right now this is a decision, hard as it was, we had to make," Rockhouse said, referring to Osborne's cancer battle.

Sonya Rockhouse at the entrance of the Pike River mine on Sunday. Photo / Supplied
Sonya Rockhouse at the entrance of the Pike River mine on Sunday. Photo / Supplied

"But we will be back and we will continue on for justice and accountability, even though when you are dealing with the Government the truth is very difficult to find."

Rockhouse said this morning the 'temporary' seal, stopped by the protesters' occupation, would actually be a 20m-thick solid concrete wall.

"We've been told a stainless steel wall was built 50m into the drift and then sprayed with concrete last Thursday. The next stage is to fill the mine-shaft completely from floor to ceiling with concrete, to a depth of at least 20m, then another wall over a metre thick to hold it.

"This is more than 100 concrete trucks' worth of concrete. It will be permanent."

She said both international experts and a local Mines Rescue expert had told them it was possible to get into the drift now to secure any human remains and evidence.

People can show their support by signing an on-line petition at www.standwithpike.nz.

- Greymouth Star