The top 90m (295ft) of an escape shaft at Chile's San Jose mine has been fully lined with metal tubing, reports say.
A winch and pulley will be installed and the shaft tested before the operation to extract the 33 trapped miners, expected to start on Wednesday.
The operation could take take up to 48 hours, with the rescue capsule taking up to 75 minutes per return trip, including getting miners in and out.
The men have been entombed since the mine partially collapsed on 5 August.
After 41 days of drilling and three separate rescue plans, engineers manning the "Plan B" drill finally broke through to the miners on Saturday morning, sparking celebrations across Chile.
The drill was driven away from the mine on Monday surrounded by crowds of photographers and cheers by hundreds of people across the site.
Engineers finished lining the top 90m (295ft) of the escape shaft with metal tubing by about 0900 Monday (1200 GMT).
They had originally planned to line down to 96m but were forced to stop short when they encountered problems in the final few metres.
The decision to stop six metres short of the planned depth would not affect the safety of the rescue shaft, officials said.
The casing will prevent rocks in the looser soil near the top of the shaft being dislodged and jamming the rescue capsule, named Phoenix.
Video examination of the shaft after Saturday's breakthrough convinced experts that they did not need to encase the whole tunnel, most of which was cleanly hewn from solid rock.
The next step is to install the winch and pulley, before going on to test the function of the capsule.
Above the ground, the helicopter flights which will deliver the men to hospital as they emerge are being rehearsed a final few times.
Tarpaulins have now been erected around the site of the Plan B drill, reports the BBC's Tim Willcox at the mine head.
They are restricting the view of the world's media, who have gathered in ever-growing numbers to report on what promises to be a rare good news with global appeal.
Some 1,000 journalists are already at the San Jose mine, our correspondent reports, with hundreds more expected in the next 48 hours.
The first four men to leave the mine have been selected by authorities, reports Chilean newspaper La Tercera. They have not been named but are thought to include some of the most psychologically stable and experienced of the miners - in case something goes wrong during the first few rescues.
Health Minister Jaime Manalich said some of the miners had shown a gallant spirit when he had spoken to them about the need to establish the order in which the men would leave.
"What was their reaction, the reaction of several of them? 'Yes minister, that's all good but I want to go last.' And then another one shows up, 'No, comrade, I had said that I would go last.' 'No, no, no. It's me,' would say another one.
"So I want to illustrate, through this anecdote from yesterday, that, in reality, they're maintaining a completely admirable spirit of solidarity, of comradeship," said the minister.
"There's no doubt that they will tell us later the details of this story from the entire time they were below, in the mine - that they've faced difficulties - but it's impressive how they themselves have managed things to maintain an enviable spirit which we all admire," he said.
Once out of the mine, the 33 men will find their world transformed from how they knew it back in August.
Aware that they will face intense media interest even as they attempt to reconnect with their families, Chile's government is offering six months of psychological and media support if they want it.
But they will be free to do as they please once they are released from hospital after medical tests.
"All of them will have to confront the media and fame, and will encounter families that aren't the same as when they were trapped," Mr Manalich told the Associated Press.
"All of them will live through very difficult situations of adaptation."