A 20 FT SECTION OF 4 INCH PLASTIC WATER LINE BECAME ENTANGLED IN THE CONT MINER CABLE AND 1 1/2' WATER LINE AS THE MINER WAS BEING TRAMMED ACROSS THE SECTION. THE MINER CABLE PULLED THE 4 INCH WATER LINE TO A POINT WHERE IT BECAME FOWLED ANDSTARTED TO BEND THE PIPE, THEN THE PIPE DISLODGED AND STRUCK THE INJURED BEHIND HIS RIGHT KNEE.