EE WAS JACKLEGGING IN SHAFT ZONE 3990 HEADING, FINISHING BOLTING THE BACK. EE DIDN'T FINISH THE BOLT ALL THE WAY BECAUSE HE NEEDED A LONGER DRIVER. EE WAS BACK DRIVING ON BOLT WHEN EE FELT A LOT OF WEIGHT ON HIS LEFT SIDE OF HIS BODY. THIS WEIGHT WAS A ROCK THAT CAME OUT OF FACE IN THE HEADING, RUSULTING IN AN INJURY TO HIS LEFT LEG ""KNEE"" & LOWER BACK STRAIN.