ON APRIL 9, 2012, INJURED CLAIMED TO HAVE STRAINED HIS LEFT SHOULDER WHILE PULLING ON VALVE HANDLE ON PRIMARY COARSE SUMP LOCATED IN BASEMENT OF PREP. PLANT. INJURED DID NOT MISS WORK, BUT CO NTINUED TO HAVE PROBLEMS WITH SHOULDER. INJURED HAD SURGERY TO REPAIR ROTATOR CUFF, AND BEGAN MISSING WORK ON JUNE 10, 2013. THIS INJURY WAS NOT REPORTABLE UNTIL THIS DATE-(JUNE 10, 2013).