A recently mined 30-foot cut taken through crosscut Belt to L1 Entry and cutting into the fully-supported L1 Entry experienced roof working and falling in the unsupported crosscut to a height of 24 that extended into the L1 Entry causing an unintentional roof fall in the supported L1 (4-foot FG Resin bolts) to a height of 42. Cave dimensions = 19 wide x 19 long x 42 high.