I was just looking for some mines around here. I know a few up in the Mojave Desert, but that's quite a drive. 4x4 access only would be a plus for the fun value, but it's not nessasary. Rock crawling isn't exactly my thing and I am more of an epediton/exploring type guy. Just thought I'd throw this out. I didn't want to pollute the other SD thread.

 

Oriflamme Canyon is a fun run with accsess to an abandoned mine. I've driven by the mine but never stopped to check it out. Its right off the 78 by Banner. You'll pass by some active mines. Don't check those out or the'll shoot you as the signs say. There are also some abandoned mines down by In Ko Pah off the I8. There are some nice SoCal trail books out there that have tons of info on mines (among other things) and the trails that lead to to them.

 

There is also Calcite Mine.

 

http://www.4wdtrips.net/

These guys do tons of exploring. Some are from SD and may know about mine sites around here.