They said once drilling starts, it will take about 48 hours to reach the pair, who are facing their eighth night trapped underground.
Earlier on Tuesday, specialist mining equipment was brought to Tasmania's Beaconsfield Gold Mine, and the two men guided rescuers to the correct position and direction for the cutting machine, known as a raise borer.
Australian Workers Union deputy national president Paul Howes said blasting had been halted, and and there had been difficulties keeping open a narrow pipe punched through to Todd Russell and Brant Webb.
The two men are able to move about a metre outside the steel cage in which they were trapped throlugh a small door into a cavity created by the rock fall.
However the 1.2 metre height of the cage means the men cannot stand.
A hole big enough to insert a plastic pipe has been drilled to enable rescuers to get food such as biscuits and water and tablets and heat packs to the miners.
Other than drops of water from within the mine itself the food was the first they had eaten since a rockfall trapped them nearly one kilometre underground last Tuesday.
Bedding and a tarpaulin have been sent to them through the pipe, and there are said to be no problems with air quality.
Second shaft
A microphone that had been sent through to the men could not be used for a time, with the miners and their rescuers having to shout to each other.
Mine manager Matthew Gill said rescuers were continuing to dig a second mine shaft to reach the men. "This work has to proceed very carefully to try to avoid any further rockfalls," he told ABC radio.
"We are examining a range of specialist equipment brought in from around the state. We are still some time off being able to get them out."
Meanwhile AWU secretary Bill Shorten said the rescue could take another 48 hours.
Yesterday, authorities had estimated it could take 24 to 48 hours to bring Mr Webb, 37, and Mr Russell, 34, because the raise borer still has to be assembled.
Mr Shorten has told the Nine Network the raise borer was a less violent method of tunnelling through the last few metres to the men, who are in the 1.3 metre by 1.2 metre cage.
"They have been using explosives to blast. Now they're sufficiently close to the men that wouldn't be the appropriate way to go," Mr Shorten said.
"This is a form of tunnel boring ... it turns the rock in front of a machine into dirt. It's less violent on its impact to the environment around it so it causes less repercussions to the rock."
"They've got to get all the right equipment down the hole. I can't see how it can be quicker, so I think we have to be patient and calm, and make sure that all the right people are in the right place doing the right job," he said.
"In addition they've had a couple of naps, and they're in good physical and mental health, which is good news," he said. "Now it's just a hard slog, the union is confident that the management team and the workers are working very hard to rescue the blokes."