[who_is_daniel]

The original mine? There's nothing the mod changes that part of the game.
Have you talked to Emerson? He's standing near the mine entrance and you need to talk to him and get his permission first

Yes I talked to him before and afterwards but it made no difference. I checked all my mods and didn't find anything that could do it. I loaded one of my backups before I ever entered the area, and went in and talked with him and was able to get into the mine that time.  So whatever the problem was it seems to have resolved itself. The only thing I did differently between the first time I was there and when I tried it again was I had cleared the entire map before trying to enter the mine, whereas the second time I went straight to the mine entrance.