AN EE WAS DUMPING A LOAD OF STONE WHICH WAS BEING USED FOR THE CONSTRUCTIO0N OF A HAUL ROAD. WHILE DUMPING THE LOAD THE ENGINE STALLED, CAUSING THE ROCK TRUCK TO FREEWHEEL FORWARD DOWN A GRAD AND OVER AN EMBANKMENT APPROX. 15' HIGH. THE TRUCK OVERTURNED ONTO ITS RIGHT SIDE. THE EE'S INJURY OCCURRED WHILE DISMOUNTING THE VEHICLE.