The specially designed bullet-shaped cage was lowered almost the entire length of the escape shaft without a hitch, Mining Minister Laurence Golborne told reporters.

Once the evacuations start, at midnight, it will take 48 hours to hoist the men up from inside the caved-in mine half a mile underground, he said.

Four rescuers will be lowered to help the miners prepare to return to the surface from the darkness of the tunnel they have been trapped in since the August 5 collapse at the gold and copper mine in the Atacama desert.

Rescue workers finished reinforcing the escape shaft on October 11. Engineers decided to line only part of the narrow, nearly 2,050 foot-long (625-meter) shaft with metal tubes, aiming to avoid any last-minute disaster.

Rescuers installed the tubes to diminish the risk of rocks breaking off the walls of the drill shaft and blocking the exit of the capsule, dubbed the "Phoenix" after the mythical bird reborn from its ashes.

President Sebastian Pinera, who has ordered a revamp of mine safety regulations in the wake of the accident, plans to visit the mine on October 12. One of the 33 miners is a Bolivian national and Bolivian President Evo Morales has vowed to visit the mine for his rescue.

Rescue officials said they would push ahead boring a separate shaft with a rig usually used to drill for oil as a back-up plan. They have halted a third drill.