EMPLOYEE WAS OPERATING A CAT D-10 DOZER IN RECLAMATION. AS HE WAS BACKING, THE DOZER RAN UPON A ROCK. THE ROCK SHATTERED ALLOWING THE DOZER TO SUDDENLY DROP, JOLTING THE EMPLOYEE IN THE OPERAT ORS SEAT. THE EMPLOYEE INITIALLY COMPLAINED OF NUMBNESS AND TINGLING DOWN HIS LEG. AS TIME PROGRESSED, HIS SYMPTOMS ALSO INCLUDED PAIN IN THE LOWER BACK. AS OF 10/23, EE IS OFF WORK DUE TO IN