EE WAS DRIVING A FUEL TRUCK FROM ONE STAGING AREA TO THE NEXT. HE SIGNALED A RIGHT HAND TURN, COMMENCED TO THE TURN, WHEN A FOLLOWING COAL TRUCK ATTEMPTED TO PASS STRIKING THE RIGHT SIDE OF TH E TRUCK. THE COAL TRUCK MISTOOK THE SIGNAL FOR AN AUTHORIZED TO PASS. PRODUCTION EQUIP MONITORS CH 20, COAL TRUCKS CH 23.