A non-injury roof fall occurred during rehabilitation work of the North mains. 18 steel arches had been installed between 6 and 5 x-cut in the #5 entry. A crib had been removed to allow more steel arches to be installed in the #5 xcut intersection. scoop brought to crib and arch, top started working 20 min later top fell. 6-8ft high, 35' long anf 18' wide.