The first of three drills has reached the 33 men trapped in a Chilean mine.
The breakthrough means the miners, who rescuers have been trying to extract before Christmas, might now be raised to the surface by early November.
The miners will be helping their own cause by clearing away the debris that falls into the mine as the drill bores through the mine's ceiling.
The rescue effort's lead engineer, Andre Sougarret, said the Schramm T-130 drill, dubbed Plan B, has reached a depth of 630m (2,070ft), arriving at an operations workshop in the mine above where the miners have holed up since a cave-in on August 5.
The drill has successfully tunnelled a hole 30cm (12in) in diameter that must now be widened to around 70cm (28in) so that rescue workers can lower down a rescue pod that will be used to hoist the miners up one by one through the narrow opening.
Rescue workers cautioned that they were still weeks away from freeing the 32 Chilean and one Bolivian miner who have become celebrities as Chileans follow the news of the rescue efforts.
Chilean President Sebastian Pinera is expected to visit the miners and their families on Saturday for a bicentennial celebration that has been planned between the family members on the surface and the miners down below.