Graphic: Complex rescue at Pike River mine

Graphic by Phil Welch / Herald on Sunday

As rescue crews wait for the go-ahead to enter the stricken Pike River mine, it is becoming clear just how difficult and dangerous a rescue attempt could be.

Trevor Watts, general manager of New Zealand Mines rescue said the greatest concern was an "explosive atmosphere" in the mine.

"We have got to be certain that we're not going to compromise the safety of the miners we're trying to rescue," he said, "or the rescue teams that we're going to deploy underground."

"The logistics of deployment underground are quite vast. We're talking 2.5km from the portal to the first intersection in the mine that will have to be done on foot by the rescue teams - this is not like walking down to the local supermarket."

On the initial reconnaissance mission, rescuers will wear 14 kilogram 'rebreather' apparatus, plus carry between five and 10kg of additional equipment.

Watt underlined the challenge of moving around down in the mine, saying it could take the rescue teams up to two hours to make the 2.5km journey.

- NZ Herald staff