A Chilean minister said Monday that a capsule which will lift 33 trapped miners out of a copper mine has descended to 610 meters underground, and the rescue operation is ready to start around midnight Tuesday.

The casing of the tunnel from where the trapped miners are expected to be brought to surface had been completed, Mining Minister Laurence Golborne told a press conference.

According to Health Minister Jaime Manalich, Golborne will name the first miner among four candidates who will ascend in the capsule. All of them have to be young, strong and endurable.

The first four miners are volunteers, and will be asked to report to ground-control about the function of the capsule, he added.

The miners have been trapped in a shelter 700 meters underground for more than two months after the collapse of the San Jose mine on Aug. 5.