I grew up there in the 1970's and we went up on the mountain all the time. I didn't know you needed permission?? Is that semi-new? We found some big caverns, but nothing in them. Looking back I'm surprised we never ran into rattle snakes.
I think I know where the mine is. Me and my friends used to hike up the mountains all the time. We found certain things that are strange up there. Of course, you got your satanic graffiti. We found a chair that we assumed was from the crashed plane. And a weird spot we're the mine mite be but I'm not telling, ha!