An unintentional roof fall occurred on unit 3 in the right side rooms @ 4+00 room #3 at station 28+70. The fall was at a 3 way intersection and mesured 18.5 feet x 20 feet x 6 feet. The fall was inby the tailpiece. The area had been bolted with 4 foot fully grouted roof bolts and is now timbered and cribbed off.