2 MINERS WERE DOING REHAB WORK IN THE 440 A20 DRIFT WHEN THEY NOTICED THE BACK FLAKING A LITTLE.THEY STOPPED WORK & WERE EVAULATING THE GROUND WHEN THEY NOTICED THE BACK STARTING TO MOVE. THE BACK STARTED TO FALL AT THE LEFT SHOULDER OF THE DRIFT & THEN EVENTUALLY WORKED IT'S WAY ACROSS THE ENTIRE DRIFT. APPROX 12'W, 30'L, 5'-7' HIGH