During the first week of July, 1984, the De LaSalle Vocational School (Philadelphia) rigged the entrance drop of Hellhole Cave in West Virginia. This was left rigged overnight.
During the night, three Marines noticed this rigging, and one hand-over-handed down to the ledge forty feet below the lip (still over 100 feet to the floor). An instructor noticed this activity, rappelled down to the victim, put him in a seat harness and had the class pull him out.
NSS News, November 1985(Part 2) V43N11, Page 366
George Dasher Personal Communication July 24, 1984
No analysis has been done.