EE WAS BEGINNING HIS SHIFT BY PERFORMING PRE-SHIFT EXAM ON COAL TRUCK. HE HAD CLIMBED INTO THE CAB & STARTED THE ENGINE & BEGAN TO DISMOUNT THE TRUCK WHEN HIS FOOTING SLIPPED, RESULTING IN HIM FALLING FACE DOWN APPROX. 3'TO THE GROUND. HE WAS NOT USING 3 POINTS OF CONTACT & ALSO HAD CLEANING SUPPLIES IN HIS HAND. HE COMPLAINED OF PAIN TO HIS FOREHEAD & ELBOW. SPRAINED ELBOW.