mines
I prospect for gold as a hobby, and just want to say that mine a has many hidden dangers. too many to list but here are some, many vertical shafts may be covered by debris, rotted support timbers and rock, bad air, oderless toxic gas, old dynamite that has crystalized = nitro glycren (sp?) one SMALL vibration and your gone. I have seen cases of dynamite in mining districts just left there on the ground, with signs warning people to stay away. the stuff has become so unstable it can't be moved.
Be careful an enjoy. use the buddy system. take two light sources. Let someone on the outside know where you are going. If you see dynamite, stop, back away, do not make any noise. get out as quiet as you can.