While conducting his weekly airway examines the examiner identified a fall in old 3Lt.Panel. The fall was located outby spad 9895#2 intersection & fell up the #2 entry for approx.120'then Lt. handed thru CC into #1 & continued outby for 100'. The fall was 20'WX220'LX4-5'H supported w/4'fully grouted. Area will not be cleaned up has been dangered off and crib & timbers set.