Hopes of finding 29 men trapped in a New Zealand mine alive were rapidly fading today, with footage of the blast at the mine four days ago showing debris flung out of the shaft like a bullet from a gun.
Robots searching the men were inching forward but hopes for a rescue were running out fast and the agonising wait for families has begun to boil over.
One of the robots moved about one kilometre into horizontal mine tunnel while the other had moved further in and a third, more powerful and better equipped robot from Australia was being prepared to be sent in to the mine, officials said.
Police said the position of the miners after almost five days is grave and hopes of a rescue have diminished, but maintained that the presence of lethal methane gas still made it too dangerous to enter the Pike River Coal mine, as the rescuers could trigger a catastrophic second explosion.
"Until the environment is stable (so) that we can send men into the mine it's not going to happen," police commander Gary Knowles told Radio New Zealand.
But family members were openly expressing their frustration and anger at the time being taken.
"I've had a gutsful ... they need to go in and have a look," Geoff Valli, whose brother Keith Valli (62), is the oldest man trapped.
"It's time for men to do what men have got to do," he said.
Drilling of a 15 cm-wide (6-inch) shaft of 162 metres had broken through to the main mine tunnel, said Daniel Rockhouse, who had attended a briefing for family members.
Mr Rockhouse was one of two men to walk out of the mine after Friday's explosion, and his younger brother Ben (21), was one of those trapped.
"I've got all the hope in the world, and that's what I'm hanging on to."
Rescuers intend to monitor the air quality from the hole and lower cameras and sound devices to check for signs of life, as there have been no indications since the blast that the miners are still alive.
A camera has already been lowered down another existing narrow hole which provided air to one of the designated safe areas off the main mine shaft, which showed some damage from the blast but no signs of life. Seismic devices to detect any sounds of tapping on rocks or pipes have also found nothing.
Surveillance camera footage from the entrance to the coal mine showed the strength and duration of Friday's blast, which lasted nearly a minute.
The force of the blast down the 2.3 kilometre (1.4 mile) main tunnel was likened by the head of the mining company to the force of a bullet leaving a gun barrel.
The mayor of the Grey District said people were still clinging to hope.
"We have got families there hoping for a miracle and until someone shows us a body we are hoping for a miracle," Tony Kokshoorn said.
Aged 17 to 62, the trapped men each carried an emergency breathing kit, which would have given up to an hour's fresh air, and only the food and water they would have taken in with them for their shift.
Mr Rockhouse and one other man walked out of the mine with moderate injuries but were unable to help rescuers pinpoint where the other men, who include two Britons, two Australians and a South African, were likely to be.
Reuters