On August 7, a group of seven experienced cavers were in Crookshank Cave, Greenbrier County, West Virginia, preparing to survey beyond Lew's Last Climb, a 20 foot pitch. This climb had been rigged with a rope for ascending a few weeks earlier, with the rope tied off to a span of rock. As Tom Hay was ascending the span or "natural bridge", it partially disintegrated. Hay fell about ten feet and landed in a pool. He was soaked, but unhurt and left the cave accompanied by another caver.
NSS News, May 1981 (Part 2) V39N5, Page A15
Mike Dyas "Cave Accidents Reports" D.C. Speleograph 32:10 Oct. 1976 p. 11.
It seems obvious that the anchor had been improperly tested. The climber may have exerted more force than necessary by a jerkiness in his ascending method. Smooth, non-bouncy ascending exerts the least force on the anchor.