On 7/03/06 an unintentional roof fall occurred on the #2 Unit, MMU-002, #1 return entry between #31xc & 32xc. This roof fall was located in the #1 entry and was supported with 6' anchor roof bolts. The roof fall measured 50' in length by 18' in width and 6 to 7' in thickness. The roof fall will not be cleaned up and all approaches have been cribbed off & flagged off.