WHILE DRIVING UNIT RIG 42 ON THE NORTH DUMP, EE HIS A POTHOLE WITH L FRONT TIRE, WRENCHING HIS BACK. EE NOTIFIED SUPERVISOR AT END OF SHIFT, BUT REFUSED TO BE SEEN AT THAT TIME STATING HE WANT ED TO GO HOME AND SEE IF HE FELT BETTER. UPON RETURNING TO WORK THE FOLLOWING NIGHT, EE REPORT TO WORK THE NEXT NIGHT WITH COMPLAINT OF CONTINUED PAIN IN BACK, WAS SENT IMMEDIATELY TO THE HOS