MINER WAS RESTING ON HIS KNEES BESIDE THE ROOF BOLTER. AS HE STOOD UP, HE HEARD HIS LEFT KNEE ""POP"". ABOUT 3 HOURS LATER, IN THE LOCKER ROOM, HE NOTICED A SWOLLEN AREA (MARBLE SIZE KNOT) ON THE BACK SIDE OF HIS LEFT LEG IN THE BEND BEHINDHIS LEFT KNEE.