If you're on a site with a construction crew (as is common with rescue
excavations), ask the foreman. They usually have both experience and
knowledge of the necessary health & safety codes, etc.; they also often have
equipment and an interest in keeping people alive...

-----Original Message-----


Just to be clear, lots of people read this list that are students or
academics with no training in this stuff. Don't try this type of thing
unless you have gotten training. I don't do this, nor do I allow my students
to do so. The cowboys of science attitude is great until you have to live
the rest of your life knowing that a field school student, volunteer, or
crew person died because you were cavalier. 

Sorry to be a downer on this, but this really matters.