EMPLOYEE WAS RIDING ON TOP OF A COAL AGE SCOOP, MODEL 488. THE SCOOP WAS GOING THROUGH A DIP AREA WITH UNEVEN BOTTOM. THE REAR OF THE SCOOP WAS SUDDENLY FORCED CLOSER TO THE ROOF BECAUSE OF THE UNEVEN BOTTOM AND DIP CAUSING EE TO BE CAUGHT BETWEEN AN AREA APPROXIMATELY 19"" HIGH CAUSING A FRACTURE OF THE L1 VERTEBRATE.