Mining officials in the western U.S. state of Utah say rescue workers have drilled to the underground chamber where six coal miners are believed to be trapped after a cave-in.
At a news conference early Friday, mine owner Robert Murray said a small hole has been drilled through the rock, creating an opening to establish communication with the miners.
Murray says that while there has been no noise from inside the chamber, air quality readings suggest there is sufficient oxygen to sustain human life if the miners survived the collapse.
Engineers are drilling a larger hole wide enough to accommodate food and water, but are hours away from reaching the underground chamber.
It could still be up to a week or more before rescue workers reach the trapped miners.
It is not clear whether an earthquake or seismic activity caused or contributed to the mine collapse.