EMPLOYEE WAS REMOVING A COVER FROM THE ROOF BOLTER TO WORK ON THE CABLE REEL. AS HE SLID THE COVER OUT OF THE WAY, THE COVER BEGAN TO SLIP OFF OF THE MACHINE. HE GRABBED THE COVER AS IT WAS SLIDING OFF AND TWISTED HIS BACK. SHORTLY AFTER THE INCIDENT HE BEGAN TO HAVE SPASMS IN HIS BACK AND WAS TRANSPORTED OUTSIDE.