Bristol, Virginia Based Alpha Natural Resources Is Expected To File For Bankruptcy Early This Week. Alpha Is The Biggest Miner Of U.S. Coal Used In Steelmaking And Is Struggling Amid The Worst Commodities Slump In More Than A Decade. Met Coal Prices Have Dropped 72 Percent Since 2011. The Decision To File For Bankruptcy Would Require The Company To Post Surety Bonds Or Similar Instruments To Cover 411-Million Dollars Of Potential Reclamation Liabilities.