The mine extends as far as can be seen in the photo and then turns right. You can follow it for about 200 feet then it is suddenly dead.
I have thought it was a trial but there seems to be too much work for it to be only that. I couldn't determine what mineral might have come from it either and couldn't find any historical references.
It is also almost devoid of formations but there are a couple of long iron straws ...
🙂
Ian
A door, once opened, may be stepped through in either direction.