Jane,
Machine trenching once you found the features? I recommend against that
technique because it is so destructive it would render the collection valueless
due to breakage and mixing. Why not construct a single-wall building shell with
a corrugated steel roof to protect the site and excavate, then move the
shell over the next location. This would give you security and allow for
controlled archaeology methods. Another idea would be to seal the features you have
exposed to vandalism with temporary protective fill and perhaps post signs
warning of deadly chemicals or "flesh-eating germs" to keep the bottle hunters
away. Although I am sure others in the room would disagree, I think mechanical
trenching is only to be used to find features and not to do the actual
digging. Recordation of the context is everything in archaeology.
Ron May
Legacy 106, Inc.