AN UNINTENTIONAL ROOF FALL OCCURRED ON THE UNIT 3 WORKING SECTION IN THE NO.3 ENTRY AT THE +9620 FOOT MARK. THE FALL OCCURRED BECAUSE THE ROCK BROKE AT & ABOVE THE ANCHOR POINT. THE AREA HAD BEEN SUPPORTED WITH 4', 5', & 6' CONVENTIONAL ROOF BOLTS. FALL MEASURED 30'X16'X4-6'. FALL AREA WILL BE CLEANED UP & SUPPORTED. SURROUNDING AREAS WILL BE CHECKED FOR ADVERSE CONDITIONS.