EE WAS PASSING BY THE FACE OF N12 & Z WHEN HE NOTICED A 35 FT DIAMETER, 20 FT THICK SECTION OF THE BACK HAD FALLEN. HE IMMEDIATELY NOTIFIED MANAGEMENT AND IN TURN MSHA WAS CALLED IMMEDIATELY. THE AREA HAS BEEN BEAMED OFF AND A GEOLOGICAL ENGINEER HAS BEEN CALLED TO EVALUATE.