This mine shaft is a very imposing and eerie piece of motherlode history. It's interesting to look at, but don't inspect too closely. Those grates and fences are there to keep you at a safe distance.
There's a sign at the entrance giving a brief description of the Bunker Hill Mine. There's also a monument for the late Tina Ray Foligno. I've added links for more information about her connection to this site.
http://tspntv.com/news-videos/items/20799-parole-denied-to-convicted-murder-jack-sackrider
http://blogs.sacbee.com/crime/archives/2013/01/ask-sacto-911-crime-qa-what-happened-to-fiddletown-man-who-murdered-girlfri.html
While the mine shaft is cool to check out, the Figgy Forest is a much more fun (and safe) area to explore. I used to come to this location when I was a kid and "hang out" in the naturally grown fort-like structures of these trees. I hope this area fuels your imagination as it did my own.
Do be wary of the poison oak in this area.
Happy hunting!
Congratulations to winston4ever for FTF!