I just discovered that both the BLM and the NPS have training programs for entering abandoned mines. This is something I will definitely look into, because as much as I would like to investigate the underground workings of important mining sites, I would also like to live long enough to report whatever I might find.
Abandoned mines are frequently time capsules, often with remarkably well preserved artifacts. Mines that closed suddenly, with the workers not being warned that they were losing their jobs at the end of the shift, are especially good candidates for this. In addition, the shape of the underground workings can reveal much about the decisions that were made by a company attempting to follow a profitable ore body.
Anybody doing much historical archaeology in the far west is going to be dealing with old mines from time to time. (And anybody doing much CRM in Nevada is going to be dealing with new mines, but that’s a topic for a different post.)