Officials say a rescue mission is under way for six miners trapped when their coal mine collapsed early Monday in the western U.S. state of Utah.
A mining company official told reporters that resuers know where the miners were located, but there has been no contact with them since the accident.
He said rescuers have been able to get no closer than 518 meters from where the miners are trapped. He said additional equipment is being brought in to help in the search.
Officials originally said the mine collapsed following a 4.0 magnitude earthquake in the area. But scientists now say the seismic measurements may have been recording the mine collapse.
Some information for this report was provided by AFP, AP and Reuters.