The hole cleared the way for a video camera to be lowered in an effort to provide the first answers to the miners' fate.
The hole, nearly 9 inches wide, reached the mine shaft between 2 and 3 a.m., said Bob Murray, chief of mine co-owner Murray Energy Corp. Crews were removing the heavy drill steel and planned send down the camera within a few hours.
There has been no word from the miners since the Crandall Canyon mine collapsed early Monday. A microphone lowered into a smaller hole yielded no sounds of life and an air sample taken through the 2-inch hole detected little oxygen.
However, officials remained hopeful that the six men trapped in the mine were still alive.