The Little Susan mine, a Uranium mine near Hidden Splendor, is one of the best preserved in the area. The mine came into existing in 1976 by Torval Albrecht and Sons, and still contains several well preserved buidings.
This makes a good family hike. Navigation is straight forward, and the history of the mine itself, as well as the roads and other remnants are fascinating. After the first 20-30 minutes, there is little shade and no water, making this a fall, winter, or spring hike. History buffs will enjoy the ruins, others will enjoy the stunning views along the way.
It goes without saying, but never enter any of the mines. They are unstable and may contain poisonous gases.