The fall was discovered by the mine foreman & MSHA Inspector as they made 001 section on 3 east mains. The fall was approx. 20' wide x 20' long and was up to 5' thick in the middle. No ventilation, people, travel or equipment was effected. The fall was between the blocks of #2 & #3 entry across from spad # 2230. This mine had been idle since May.