All of the mines that I went into in this canyon,
Either side of the canyon
Are within about 1/2 mile from a very large Mission building!
Roughly, 45 x60' in length
I have a photo or two of the mission, I'll dig them up and post them!
A couple of the mines are right out the back door of the mission
AND!
I mean,
right out the back door...
One false step and
you're in the mine ! :P
They may even go under the floor of the mission,
As I did venture into one of them and the tunnel went down and then turned and was headed that direction!
Maybe a
storage area/room? :P
Also,
A couple of the mines are, right across the canyon/creek along the north wall, from the mission !
Plus!
There are no signs a road to any of the mines!
Which just reminded me,
That is a solid rock ledge, about 2' high that has a trail, foot traffic, that cut the outcropping all of the way to the ground!
Now!
It means that there was one heck of a lot of foot traffic over that ledge to cut a trail thru solid 2' of rock, that deep!

There is an explanation
to some of this traffic ...
At the very head of the canyon, and there is a well used trail, going a few miles due west, and then over the top, lies
The Virgin of Guadalupe Mine ! 
I'll post a photo of this also!