- Situated some 40m from A1, up valley and slightly higher up the east slope, the hole lies in an obvious E-W fault.
A 14m pitch drops into rift passage quickly choking to the east. To the west, a short walk reaches a 3m climb to a higher level, choking rapidly.
Thought by the Austrians to be one of a group of shafts numbered 36
in the Kataster, but the location of B1 relative to B4
, which is very near 36, precludes this interpretation. Unfortunately, B1 was not relocated in a search in 1990.