Well, as a professional archaeologist I can say many of you are WAY of base here. It is almost impossible for a professional archaeologist to steal anything from a site or dig, though I'm sure it happens on a limited extent. Furthermore, once the artifacts are collected there is a very complicated and well-enforced recording system and chain-of-evidence system that prevents them from ever leaving the repository they are sent to- I.E. they are not sold, thrown away, etc as some of you have posted. All of the artifacts excavated in Arizona go to the UofA or NAU.
Why does this happen? Many of you have posted that they disappear into the vaults and basements never to be seen again. Nothing is farther from the truth. These artifacts are constantly being researched and studied by archaeologists, grad school students, and even the public. That is why they are collected- so we can learn something from them and hopefully teach future generations and living people what happened, how, why, when, where, etc. Once you remove an artifact from its surroundings (we call it context) it loses much of its value as a scientific object and just becomes an antique. That is why the laws are there- to protect the information potential. You would be stunned how much I can tell you about a single flake or a small site containing nothing but a few flakes if I see it in its original setting. But if you gather it up and put it in a bag and bring it to me I can only tell you half as much.
Why are they kept in repositories "or basements"? Because there isn't enough museum space to display them all. Almost anyone can actually view the artifacts if they have a valid reason- even the general public. Every artifact tells a story and a huge part of that story is the context in which it is found. In a lot of cases, the context is actually more important than the artifact itself. Archaeologists know a lot and are able to understand things that the general public usually cannot simply because they do this every day all day and have the knowledge base. That being said, some of the most interesting things I've ever seen have been brought to my attention by amatuers or just people wandering around.
So, as far as the LDM? What would I do if I found it? I consider myself a very ethical archaeologist and I've never stolen or sold anything I've ever found (which is an amazing amount of very VERY cool stuff). If I found the mine I would record and document every aspect of it- photos, gps coordinates, accurate maps, drawings, samples of the ore, notes, measurements, etc. and anonymously mail it to the UofA where it would be used as historical evidence and boost our knowledge of history. But before I sent that package, I'd mine every damn last bit of gold out of it. After all, in the case of a gold mine it isn't the gold that is important to history, but all the aspects of that mine- how it looks, how it is constructed, where it is, the trash that may be nearby, the size of the portal, the timbering methods, etc. You get the point.
Cornelius