New Zealand mine: Second robot to resume search
Efforts to investigate the New Zealand mine where 29 people have been missing since an explosion on Friday have resumed after a new robot's arrival.
The first one to be sent down the Pike River mine on South Island broke down.
Engineers are also close to completing the drilling of a test shaft that will allow them to assess the air quality.
Earlier, the head of the police force said it was still not safe for rescue teams to go in, and that the situation was getting "bleaker by the hour".
"This is an extremely dangerous situation, I can't stress that enough," Police Commissioner Howard Broad told reporters.
He said the risk of a secondary explosion remained high.
But the chief executive of the mine's operator, Pike River Coal, insisted there was still hope that there were survivors.
"I think it's becoming obvious there's not 29 guys sitting together waiting to be rescued," Peter Whittall said.
"How many of them there are I don't know. But those are the ones we need to rescue, and those are the ones I'm waiting to see."
There has been no contact with the miners - 24 New Zealanders, two Australians, two Britons and a South African - since Friday.
Mr Whittall said the drilling of a bore hole into the mine is still 10m short of its target of 162m, and would be completed overnight.
His comments came after CCTV footage of the explosion - the cause of which has not been confirmed - was broadcast.
It showed stonedust being blown out of the entrance to the mine tunnel for several seconds after the explosion.
Mr Whittall said they know that the blast went on for a long time, and occurred 2.5km (1.55 miles) away from where the video was taken.
Each miner carried 30 minutes of oxygen, enough to reach oxygen stores in the mine that would allow them to survive for several days in spite of the build-up of carbon monoxide and methane.
While the men would reportedly have been carrying flasks of water, there is no food underground. Their cap lamps' batteries last 24 hours.