On a trip to Ruth Cave on Monday, July 29, cavers were working on a dig in the Cricket Room. They were bringing rocks down by tying webbing around them and pulling. Chris Brinker had one "watermelon sized" rock fall unexpectedly, narrowly missing his head. They aborted the dig at that point.
NSS News, December 1992 (Part 2) V50N12, Page 347-348.
John Chenger "July 29, Ruth Cave, Huntingdon County, PA" The Loyalhanna Troglodye, (5) 1, Fall 1991, p 22.
No analysis has been done.