It is now thought a fire burning in the mine after a series of explosions is being fed by coal as well as gas, adding to the difficulty of making the mine safe enough to enter.
Pike River Coal mine chief executive believes it is "quite highly likely" part of a coal seam has caught fire "but that's not necessarily throughout the whole mine".
Efforts continued last night to use a GAG engine to starve the West Coast mine of oxygen, to allow rescue teams to try to find the men's bodies. It was hoped the machine would be in place for use between midnight and 1am today.
Mr Whittall said yesterday he did not know what condition the bodies of the miners would be in, but they could be some distance from the fire.
Asked about the families' hopes of getting bodies out, he said: "I'm sure there's still people in their inner hearts have some hope of even finding a [miner] tapping on a pipe or something.
"But I think largely there is a resignation now, obviously, to the total loss of life, and I think there's also a resignation amongst some that they may not get their family back as they wish they would."
Carol Rose, whose son Stuart Mudge is among the dead, said her family had never really had any hope of getting his body out of the mine.
"We accepted that almost from the beginning," she said.
"I'm of the opinion that [Mr Mudge's] got a very nice burial place. He's in a beautiful mountain.
"We are quite OK for him to stay there."
Mrs Rose said she and her family continued to follow developments in the retrieval effort closely, despite their views.
"There are a lot of people that really would like to get their loved ones back and for them we just hope they can get them back."
Superintendent Gary Knowles said police involved in the recovery operation were realists, and forensic experts were ready to help identify remains.
An Australian expert on mining explosions was due to arrive on the West Coast last night to assist with the recovery operation.
Mr Whittall said the GAG machine could require up to nine hours of use to be effective.
"We may have to redeploy the GAG again, and we may have to do it again and again, depending on what happens with the fire and how deep-seated it is."
The use of the GAG engine a jet engine producing water vapour was delayed yesterday morning when polyurethane used to seal the mine portal caught fire. The fire lasted about an hour but set back the use of the GAG by several hours, Mr Whittall said.
Asked yesterday about the possible reopening of the mine, Mr Whittall said he hoped the mine would not have to remain closed for the entire length of the wide-ranging royal commission of inquiry into the tragedy.
However, he accepted that inquiries by police, the coroner and the Department of Labour into the specifics of the Pike River mine incident would have to be completed before any reopening.
Prime Minister John Key has said men will not be going back into the mine to work until all parties consider it safe.
- The New Zealand Herald/NZPA
