I just visited there. It's on a mountainside between Luning and Mina, NV. There are some pics of the mine tunnel at intrepidexplorers dot org (not advertising for them...do a search there) and some video on youtube...search for 928_0230.MOV and you'll find some other posted vids of the mine and mill site. Two people were killed at the mill when it was operating and presumabely are the two marked graves (USGS topos) on the nearby trail....about a 1/2 mile south.
UC is using some of the tunnels for seismic recording. They have it wired with some high-tech sensors and a satellite dish uplink. You'll see it in the vids. Enjoy.
Intrepid Explorer