LIFTING A 300 LB METAL BOX TO BE INSTALLED IN CHUTE WITH BACK HOE BUCKET & CHAIN. BOX WAS NOT HANGING STRAIGHT AFTER PICKING IT UP 3 FT., ATTEMPTED TO STRAIGHTEN BOX WHEN THE BACK END CAME LOO SE, BOX SLID DOWN LEG & STRUCK TOP OF RIGHT FOOT, BREAKING 1 BONE & CHIPPING ANOTHER.