The Rescue Shaft

The following steps are how the rescue shaft was drilled:
1. A 33 cm pilot hole was drilled down to the miners.
2. Then the hole was "reamed" with a larger drill that widened the diameter between 60 and 70cm.
3. The third step shows the rescue capsule getting lowered down to rescue the workers.

Below is the illustration of the method they used
to drill the rescue shaft.
The above information was extracted from the following website:http://www.bbc.co.uk/news/world-latin-america-11133018