It is currently making its first pass down with a 12.5-inch diameterhole to the roof of the 50-square-meter (500-square-foot) refuge at Level 100 (100 meters above sea level).
It is currently drilling a 17.5-inch diameterhole -- smaller than the 28 inches required to rescue the miners -- in an effort to realign after veering off course over the weekend.
Drilling a 2 or 3 foot hole can be done with normal equipment, while drilling a ten, fifty, or one hundred foot diameter vertical hole would require an entirely new invention.