Roof fall discovered on the North Mains, outby section & loading points. Developement date: Nov. 2006, 300 ft. coverage. Area bolted with 6 ft double lock bolts - 7/8"" dia, grade 75, 8x8 inch roof plates with roof mat installed. Fall: 16 ft wide x 16 ft long x 10 ft high. No injuries, no equip involved, no ventilation or escapeway blockage. Notification made within 15 minutes.