NEW YORK--(BUSINESS WIRE)--The addition of Alpha Natural Resources' approximately $2.3 billion of bond debt to the default tally drives Fitch Ratings' U.S. high yield metals/mining sector default rate up to 10% for the trailing 12-month period. Today's widely anticipated bankruptcy filing by Alpha is the latest in a series of defaults in the struggling metals/mining sector. Other recent coal bankruptcies include Walter Energy Inc. and Patriot Coal Corp, which filed its second chapter 11 bankrup