The Upper Big Branch mine explosion killed 29 miners . It is the worst mining disaster in the United States since 1900 . The mine had a spotty safety record . Tuesday 's ceremony will include state dignitaries and the victims ' families .
The Upper Big Branch mine explosion killed 29 men . It is the worst mining disaster in the United States since 1972 . The mine had a spotty safety record . Tuesday 's ceremony will include state dignitaries and the victims ' relatives .