THE WORKER WAS SERVICING THE RUBBER TIRE DOZER AT THE CENTRAL CRUSHER STOCKPILE. UPON FINISHING THE TASK, THE WORKER RETURNED TO THE LUBE TRUCK CAB BY PLACING BOTH FEET ON THE ACCESS STEP HOLD ING THE UPRIGHT GRAB IRON WITH HIS RIGHT HAND WHILE REACHING FOR THE TRUCK DOOR HANDLE WITH HIS LEFT HAND. HIS FEET SLIPPED & HE FELL APPROX. 3'TO THE GROUND STRIKING HIS LEFT SIDE.