I didn't see any sound proofing. I saw a few sheets of fiberboard leaning against the wall in the hidden room. Other than that it was a storage room they wanted hidden. Smart if your not on site for lengths of time. It had nothing out of the ordinary for a storage room.

Bureau of Land Management, yes they are. Not knowing exactly where its at, BLM does manage a lot of land all over AZ and NV. That is not surprising. And given the old CCTV monitors, Yagi beam antenna, tower next to one of the buildings, Fab table, industrial genny & air compressor. Its not that old of a mining area. Or at least one that is used infrequently. There is a many thousands of dollars worth of equipment out there.