Too bad that precise details are not available. A TV story stated that he "lost control" midway in his rappel,which suggests something other than a free fall from fifty feet up, an event which is usually fatal (as in the cited article on figure eight/ carabiner breakage).

The rigging for the extraction intrigued me - much more elaborate and substantial than the set up we rigged for a similar mine shaft rescue many moons ago (1979s).
Geezer in Chief