An unintentional roof fall occurred on Unit 1 MMU (001) working section in the last open crosscut between #3 and #4 entries at the +1885 foot mark. The fall occurred due to the failure at just above the anchor point, slip broke out from the roof at approx. 5-6'. The fall measured approx. 18' w x 40'. 1x5-6'. h. The roof was orginally supported with 5' conventional type roof bolts.