ON 5/12/03 EE WAS BOUNCED AROUND IN A CAB OF A HYDRAULIC SHOVEL WHEN THE CENTER PIN BROKE CAUSING THE HOUSING TO SEPARATE FROM THE UNDERCARRIAGE. THE EE WAS TAKEN TO THE ER TO BE EVALUATED FOR LOW BACK PAIN. HE WAS DIAGNOSED WITH A MINOR LUMBAR STRAIN & RELEASED W/O RESTRICTIONS. DISCOMFORT DID NOT SUBSIDE & PAIN LATER DEVELOPED IN UPPER BACK BETWEEN SHOULDER BLADES.