Listfolks:
 
I have to agree that even a 1.2 m deep pit can be dangerous. Many
years ago I was excavating an unlined privy pit in Baltimore out
in the Fells Point area.  The pit had been dug into extremely
sandy and poorly consolidated soil to a depth of about 4 feet
(chest-high).
 
We had bisected the pit, and I was sitting in the bottom of the
hole cleaning the profile of the unexcavated portion for a photo
when I heard a noise behind me. I turned and jumped to my feet
just in time to be buried up to my chest by the collapsing
subsoil.  I was able to get free only with assistance.
 
Ya just can't be too careful...
 
John
 
John P. McCarthy
Senior Research Fellow
Institute for Minnesota Archaeology/
Principal, Senior Archaeologist/Historian
IMA Consulting, Inc.