EE HAD OUTSIDE MILL BDLG., TO MOVE 50W STACKER. MAINTANCE WAS FABRICATING NEW FLOORING FOR NEW CONVEYOR ACCESS. THEY BRIEFLY REMOVED FLOORING TO CUT & EDGE IN ORDER TO FIT. AREA WAS NOT PROPERLY TAPED OFF--EE WALKED BACK INTO MILL & FELL 4' INTO HOLE. SUFFERED GASH TO LEFT SHIN AREA.