FILE - This Aug. 22, 2006 file photo shows a coal mine seen from the air in northeast Wyoming near Gillette, Wyo. A spokesman for U.S. Sen. Lisa Murkowski said Friday, Feb. 8, 2013 that

 

              FILE - This Aug. 22, 2006 file photo shows a coal mine seen from the air in northeast Wyoming near Gillette, Wyo. A spokesman for U.S. Sen. Lisa Murkowski said Friday, Feb. 8, 2013 that
FILE - This Aug. 22, 2006 file photo shows a coal mine seen from the air in northeast Wyoming near Gillette, Wyo. A spokesman for U.S. Sen. Lisa Murkowski said Friday, Feb. 8, 2013 that federal review has so far found no evidence mining companies knowingly skirted royalty rules as they've increased coal exports to Asia. (AP Photo/Nati Harnik, File)