A ROOF FAILURE WAS DISCOVERED ON HG-17 APPROXIMATELY 4000' FROM FACE. THE FALL MEASURED 50' X 19' X 5'. LOCATED NEAR SPAD 16402 IN THE #1 ENTRY. ALL APPROACHES HAVE BEEN CRIBBED. THE AREA HAD PREVIOUSLY BEEN SUPPORTED BY 6' TORQUE TENSION BOLTS & CRIBBED DOWN RIGHT SIDE.