THE EXCAVATOR WAS LOCATED @ BASE OF A SHOT THAT WAS BLASTED THE PREVIOUS DAY, W/THE BOOM POSITIONED PARALLEL TO THE MUCK PILE & THE CAP RIGHT NEXT TO THE PILE. THE EE WAS USING THE HYD HAMMER TO BREAK SOME OVERSIZED ROCKS WHEN A ROCK SLID OFF THE SHOT & ROLLED INTO CAB OF MACHINE. CAB OF EXCAVATOR SUSTAINED DAMAGE & EE RECEIVED 6 STITCHES IN RIGHT LEG BELOW KNEE.