Toxic gas levels remained too high today to start a rescue of 29 men trapped in a New Zealand coal mine for nearly three days.
Drilling continued on a new shaft to test air quality.
There has been no contact with the miners since an explosion ripped through the Pike River colliery on the rugged west coast of New Zealand's South Island on Friday afternoon, with authorities saying the gas level made it too dangerous to enter the mine.
'The risk of a secondary explosion is paramount in the minds of the rescue people,' the chairman of the mine company John Dow told Radio New Zealand.
'They need to know what that environment is like and that it's safe for the rescuers to go in...it's a delicate situation.'
An explosion of naturally occurring methane gas is thought to have caused the explosion. High levels of gas have been detected near mine ventilation shafts.
Drilling of the new 15cm shaft on a steep hillside above the mine started this evening (New Zealand time) and went through the night.
It was reported to be about halfway down the 150m estimated depth to reach an area of the tunnel closer to where the trapped miners might be.
Authorities have said that it is possible that the miners have survived the blast and are in an area where the air is cleaner.
Tests on the air quality are being conducted every 30 minutes at the mine's shafts, but the toxic gas levels have been fluctuating. They needed to be falling to allow rescue teams to go in.
Families and friends of the trapped men were to be briefed on the progress, although Mr Dow said there was not too much new to tell them.
However, the Grey District mayor said emotions were running high and people were frustrated at the slow pace of the rescue.
'It's a crunch, crunch day today, we've got to get some resolution, some movement forward because the desperation is turning to grief,' Tony Kokshoorn said.
The trapped men range in age from 17 to 62 and include two Britons, two Australians and a South African. Two men escaped from the mine after the blast with moderate injuries.
The weather in the mountains in which the mine is situated was generally fine and sunny for the first time in several days.
The isolated mine has been dug about 2.3km horizontally into a mountain range, with the trapped men believed to be most of the way inside.
30 rescuers, including Australian experts, are ready to go, but it has been estimated that it would take them around two hours to walk over the uneven ground and through dark, smoke-filled tunnels.
