FILE – In this May 16, 1939 file photo, their day’s work done, miners who reported for duty for the Harlan Central Coal Company near Harlan, Ky., leave the mine under the guard of troops who escorted them through a picket line. The union era’s death knell sounded in Kentucky on Dec. 31, 2014, when Patriot Coal announced the closing of its Highland Mine. (AP Photo/Preston Stroup, File)