NEW : President Bush says he and first lady are deeply saddened by the tragedy . Mine Safety and Health Administration chief : Tests showed underground oxygen levels were too low to sustain human life . We ' ve run out of options . The six miners have been trapped underground since August 6 . Seven bore holes drilled into the mine have found no signs of life .
NEW : President Bush says he and first lady are deeply saddened by the tragedy . Mine Safety and Health Administration chief : We ' ve run out of options . The six miners have been trapped underground since August 6 . Seven bore holes drilled into the mine have found no signs of life .