EMPLOYEE STATES THAT HE HAD TRAMMED THE COAL-HAULER TO THE SECTION DUMPING POINT AND WAS RETURNING TO THE FACE OF THE NO.2 ENTRY. HE STATES THAT HE WAS BACKING DOWN THE NO 2 ENTRY WHEN HE RAN OVER A ROCK IN THE ROADWAY. THE BOUNCE OF THE COAL-HAULER CAUSED HIM TO COME OUT OF HIS SEAT AND BACK DOWN. HE STATED THAT HIS LOWER BACK HURT AND THE PAIN SPREAD TO HIS SHOULDERS & LEFT ARM.